ICWS 2006

Semantic Interoperability of Web Services - Challenges and Experiences

Meenakshi Nagarajan,Kunal Verma,Amit P. Sheth,John Miller,Jon Lathem — 9/03/2007 04:58

With the rising popularity of Web services, both academia and industry have invested considerably in Web service description standards, discovery, and composition techniques. The standards based approach utilized by Web services has supported interoperability at the syntax level. However, issues of structural and semantic heterogeneity between messages exchanged by Web services are far more complex and crucial to interoperability. It is for these reasons that we recognize the value that schema/data mappings bring to Web service descriptions. In this paper, we examine challenges to interoperability; classify the types of heterogeneities that can occur between interacting services and present a possible solution for data mediation using the mapping support provided by WSDL-S, the extensibility features of WSDL and the popular SOAP engine, Axis 2. buy now

An Approach for Specifying Capability ofWeb Services based on Environment Ontology

Puwei Wang,Zhi Jin,Lin Liu — 1/10/2007 20:00

Capability specification is key problem for Web service discovery. Conventional one-step process based capability specification has its limitations. This paper proposes an approach for semantic behavior-based capability specification of Web service to stride over the limitations. Meta-level environment ontology is proposed to provide formal and sharable specifications of environment resources in a particular domain. For each environment resource, there is a corresponding hierarchical state machine specifying its dynamic characteristics. Then, effects on the environment resources are modelled with the hierarchical state machines. On the basis of the environment ontology, forest-structured communicating hierarchical state machines (FCHM) are defined and expected to be semantics of capability specification of Web services, which can be derived from the effects that Web services impose on their environments. buy now

Metadata-Based XML Serialization for Embedded C++

Szabolcs Payrits,Péter Dornbach,István Zólyomi — 1/29/2007 00:30

Mapping XML document schemas and Web Service interfaces to programming languages has an important role in effective creation of quality Web Service implementations. This paper presents a novel way to map XML data to the C++ programming language with emphasis on use in mobile and embedded systems. The proposed solution offers more flexibility and more compact code that is critical in embedded environments. The paper describes the concept and the architecture of the solution and compares it with existing solutions. buy now

A Cooperative and Adaptive System for Caching Web Service Responses in MANETs

Hassan Artail,Hasan Al-Asadi — 1/10/2007 20:13

This paper proposes a new model for caching Web service response data in a mobile ad hoc network (MANET). The aim is to enable any node joining the Ad Hoc network to either contribute services to other nodes or to consume services offered by other nodes. This model attempts to coordinate the service discovery and service use processes while maintaining minimal communication among nodes. The system comprises Proxy Caches (PCs), for acting as the interface to remote Web services and the internally cached service responses, Request Directories (RDs) for caching the cache keys that act as indexes to the responses, and finally, the Caching Nodes (CNs) that cache the responses. The CNs are the mobile nodes that requested the cached responses while the RDs are the ones that store the cache keys generated from the submitted requests and hold pointers to the CNs that store the responses. The PCs, RDs, and CNs are added (assigned) based on need according to capability criteria. Experimental results show the superiority of the system over non-caching and illustrate its performance in terms of delay and load versus hit ratio, which is a function of the system’s caching capacity. buy now

A Lightweight Framework forWeb Services Invocation over Bluetooth

Vincenzo Auletta,Carlo Blundo,Emiliano De Cristofaro,Guerriero Raimato — 12/20/2006 15:33

We present an experiment relative to the use of Bluetooth wireless technology to provide network support for midlet applications accessing Web Services. We refer to the most common architecture used to invoke Web Services, where a client and a server exchange SOAP messages using HTTP as the transport protocol. To the best of our knowledge, there is no implemented support for executing a HTTP POST operation over a Bluetooth channel. Therefore, to guarantee the independence of the application from the type of communication channel used, in this paper, we deal with the problem of designing a framework allowing a Java application programmer to directly interface Web Services from a mobile device using a Bluetooth connection. This paper presents a proof of concept of how Bluetooth technology can be used to design, develop, and deploy Web Services-based applications. According to our experiments, programming interfaces like Blue Cove and kSOAP, despite being still under development, are mature enough to be used as the underlying technologies for Web Services invocation over Bluetooth in a real world application.buy now

DSCWeaver: Synchronization-Constraint Aspect Extension to Procedural Process Specification Languages

Qinyi Wu,Calton Pu,Akhil Sahai,Roger Barga,Gueyoung Jung — 1/10/2007 20:21

BPEL is emerging as an open-standards language for Web service composition. However, its procedural style can lead to inflexible and tangled code for managing a crosscutting aspect — synchronization constraints that define permissible sequences of execution for activities in a process. In this paper, we present DSCWeaver, a tool that enables a synchronization-aspect extension to BPEL. It uses DSCL, a synchronization expression language, to specify constraints. DSCL has the desirable features of declarative syntax, fine granularity, and validation support. A designer can use DSCL to describe and validate the synchronization behavior and rely on DSCWeaver to generate BPEL code. We demonstrate the advantages of our approach in a service deployment process and evaluate its performance using two metrics: Lines of Code (LoC) and Places to Visit (PtV). Evaluation results show that our approach can effectively reduce development effort of process designers while providing performance competitive to un-woven BPEL code. buy now

Workflow discovery: the problem, a case study from e-Science and a graph-based solution

Antoon Goderis,Peter Li,Carole Goble — 12/20/2006 15:31

Much has been written on the promise of Web service discovery and (semi-) automated composition. In this discussion, the value to practitioners of discovering and reusing existing service compositions, captured in workflows, is mostly ignored. This paper presents one solution to workflow discovery. Through a survey with 21 scientists and developers from the myGrid workflow environment, workflow discovery requirements are elicited. Through a user experiment with 13 scientists, an attempt is made to build a gold standard for workflow ranking. Through the design and implementation of a workflow discovery tool, a mechanism for ranking workflow fragments is provided based on graph sub-isomorphism matching. The tool evaluation, drawing on a corpus of 89 public workflows from bioinformatics and the results of the user experiment, finds that the average human ranking can largely be reproduced. buy now

Indexing Business Processes based on Annotated Finite State Automata

Bendick Mahleko,Andreas Wombacher — 12/20/2006 15:29

The existing service discovery infrastructure with UDDI as the de facto standard, is limited in that it does not support more complex searching based on matching business processes. Two business processes match if they agree on their simple services, their processesing order as well as any mandatory or optional requirements for the service. This matching semanctics can be formalized by modelling business processes as annotated finite state autamata (aFSAs) and deciding emptiness of intersection aFSA. Computing the intersection of aFSAs and deciding emptiness are computationally expensive, being more than quadratic on the number of states and transistions, thus does not scale for large service repositories. This paper presents an approach for indexing and matching business processes modeled as aFSAs, for the purpose of service directory. Evaluation of this approach shows a preformance gain of several orders of magnitude over sequential matching and linear complexity with regard to the data size. buy now

Reliable Messaging for BPEL Processes

Anis Charfi,Benjamin Schmeling,Mira Mezini — 12/20/2006 15:28

There are currently two specifications that address reliable messaging in Web Services: WS-ReliableMessaging and WS-Reliability. Both specifications consider the general case of Web Services as being black boxes with WSDL interfaces. In this paper, we address the reliable messaging requirements of Composite Web Services in BPEL. In such Web Services, the BPEL programmer sees not only the WSDL interface but also the implementation, i.e., the process definition. BPEL processes have several reliable messaging requirements, which cannot be supported by current reliable messaging specifications. The most challenging of those requirements is to support ordered message delivery between many endpoints. Current reliable messaging specifications support only reliable messaging between two endpoints. This paper presents several approaches to support multi-party reliable messaging and introduces a reliable messaging Web Service for BPEL that is integrated with a BPEL engine by using a process container framework. This Web Service supports the reliable messaging requirements of BPEL processes and its implementation is based on Sandesha, which is an open source implementation of WS-ReliableMessaging. buy now

From BPMN Process Models to BPEL Web Services

Chun Ouyang,Marlon Dumas,Arthur H.M. ter Hofstede,Wil M.P. van der Aalst — 12/20/2006 15:26

The Business Process Modelling Notation (BPMN) is a graph-oriented language in which control and action nodes can be connected almost arbitrarily. It is supported by various modelling tools but so far no systems can directly execute BPMN models. The Business Process Execution Language for Web Services (BPEL) on the other hand is a mainly block-structured language supported by several execution platforms. In the current setting, mapping BPMN models to BPEL code is a necessary step towards unified and standards-based business process development environments. It turns out that this mapping is challenging from a scientific viewpoint as BPMN and BPEL represent two fundamentally different classes of languages. Existing methods for mapping BPMN to BPEL impose limitations on the structure of the source model. This paper proposes a technique that overcomes these limitations. Beyond its direct relevance in the context of BPMN and BPEL, this technique addresses difficult problems that arise generally when translating between flow-based languages with parallelism. buy now

Access Control and Authorization Constraints for WS-BPEL

Elisa Bertino,Jason Crampton,Federica Paci — 12/20/2006 15:26

Computerized workflow systems have attracted considerable research interest in the last fifteen years. More recently, there have been several XML-based languages proposed for specifying and orchestrating business processes, culminating in WS-BPEL. A significant omission from WSBPEL is the ability to specify authorization information associating users with activities in the business process and authorization constraints on the execution of activities such as separation of duty. In this paper, we address these deficiencies by developing the RBAC-WS-BPEL and BPCL languages. The first of these provides for the specification of authorization information associated with a business process specified in WS-BPEL, while BPCL provides for the articulation of authorization constraints. buy now

Towards Service-Oriented Ontology-Based Coordination

Thierry Moyaux,Ben Lithgow Smith,Shamimabi Paurobally — 12/20/2006 15:23

Coordination is a central problem in distributed computing. The aim is towards flexible coordination, managed at run-time, in open, dynamic environments. This approach would benefit from an explicit common vocabulary for coordination and hence, in a previous paper, we modelled coordination in an ontology, describing the activities carried out and the interdependencies among these activities. The purpose of this paper is to show how such an ontology can be used alongside a set of rules to perform coordination by managing the interdependencies among activities. The ontology and rules can then be used to provide a general purpose coordination tool in the form of a web service. buy now

Optimal Adaptation in Web Processes with Coordination Constraints

Kunal Verma,Prashant Doshi,Karthik Gomadam,John Miller,Amit Sheth — 12/20/2006 15:23

We present methods for optimally adapting Web processes to exogenous events while preserving inter-service constraints that necessitate coordination. For example, in a supply chain process, orders placed by a manufacturer may get delayed in arriving. In response to this event, the manufacturer has the choice of either waiting out the delay or changing the supplier. Additionally, there may be compatibility constraints between the different orders, thereby introducing the problem of coordination between them if the manufacturer chooses to change the suppliers. We focus on formulating the decision making models of the managers, who must adapt to external events while satisfying the coordination constraints, using Markov decision processes. Our methods range from being centralized and globally optimal in their adaptation but not scalable, to decentralized that is suboptimal but scalable to multiple managers. We also develop a hybrid approach that improves on the performance of the decentralized approach with a minimal loss of optimality. buy now

WSBen: A Web Services Discovery and Composition Benchmark

Seog-Chan Oh,Hyunyoung Kil,Dongwon Lee,Soundar R. T. Kumara — 12/20/2006 15:20

A novel benchmark, WSBen, for testing web services discovery and composition is presented. WSBen includes: (1) A collection of synthetic web services (WSDL) files with diverse characteristics and sizes; (2) Test discovery and composition queries and solutions; and (3) External files for statistical analysis and AI planners. Users can fine-tune the generated WSDL files using various parameters such as skewness or matching type. It is our hope that WSBen will provide useful insights for researchers evaluating the performance of web services discovery and composition algorithms and softwares. buy now

Exploring Remote Object Coherence in XMLWeb Services

Robert van Engelen,Madhusudhan Govindaraju,Wei Zhang — 12/20/2006 15:20

Object-level coherence in distributed applications and systems has been studied extensively. Object coherence in platform-specific and tightly-coupled systems is achieved with binary serialization protocols to ensure data structures and object graphs are safely transmitted, manipulated, and stored. On the opposite side of the spectrum are platform-neutral Web services that embrace XML as a serialization protocol for building loosely coupled systems. The advantages of XML to connect heterogeneous systems are plenty, but rendering programming-language specific data structures and object graphs in text form incurs a performance hit and presents challenges for systems that require object coherence. Achieving the latter goal poses difficulties by a phenomenon that is sometimes referred to as the "impedance mismatch" between programming language data types and XML schema types. This paper examines the problem, debunks the O/X-mismatch controversy, and presents a mix of static/dynamic algorithms for accurate XML serialization. Experimental results show that the implementation in C/C++ is efficient and competitive to binary protocols. Application of the approach to other programming languages, such as Java, is also discussed. buy now

Developing a Selection Model for Interactive Web Services

Shuchao Wan,Jun Wei,Jingyu Song,Heqing Guan — 12/20/2006 15:17

Traditional web services are function oriented, where various developed standards mainly assist business applications to expose their functional descriptions, but each service consumer is required to develop different presentation logics for the same business logic respectively. Although works on the Interactive Web Service (IWS) make some progress and achieve the result of WSRP, researchers keep on making efforts to encapsulate user interface with the functional interface so as to present available information of content and facilitate the direct interactions between users and back-end services. Regarding IWS this paradigm of web services, service selection will shift focus from function orientation to presentation orientation. This paper proposes a novel IWS description model with the extension of an element -View and its three sub-elements including presentation, content and interaction, with which IWS can be described more completely and accurately. Based on the description model, an IWS selection model with matching rules is developed, which can meet diverse selection requirements of service consumers at multiple levels and aspects. buy now

Semantic Modeling and Design Patterns for Asynchronous Events in Web Service Interaction

Li Li,Wu Chou,Feng Liu,Dan Zhuo — 12/20/2006 15:16

This paper proposes a conceptual model for modeling static and dynamic event sources by reusing the information in WSDL. A set-theoretic semantics for event subscription is introduced, based on which two metrics, recall and precision, are proposed to measure the accuracy of event subscriptions. We discuss the accuracy of several event subscription strategies under the framework of current web service event subscription standard proposals (WS-Eventing and WS-Notification). Four major types of event broker design patterns are discussed based on two visibility/reachability factors: if sink knows the source and if source can deliver events directly to the sink. The implication on the broker state and message routing is studied in this analysis. A prototype implementation indicated that these design patterns are feasible. buy now

PWSSec: Process for Web Services Security

C. Gutierrez,E. Fernandez-Medina,M. Piattini — 12/20/2006 15:16

In the last few years, the field of Web Services (WS) security has evolved rapidly producing an impressive number of WS-based security standards. This fact has caused that organizations are still reticent about adopting technologies based on this paradigm due to the learning curve necessary to integrate security into their practical deployments. In this paper, we present PWSSec (Process for Web Services Security) as a process that enables the integration of a set of specific stages into the traditional phases of WS-based systems development providing them with security. PWSSec is composed of three stages, WSSecReq (Web Services Security Requirements), WSSecArch (Web Services Security Architecture) and WSSecTech (Web Services Security Technologies) that allow the specification of WS-specific security requirements, the definition of the WS-based security architecture and the identification of the security standards that the security architecture must deploy, respectively. buy now

A Table-Driven Streaming XML Parsing Methodology for High-Performance Web Services

Wei Zhang,Robert van Engelen — 12/20/2006 15:13

This paper presents a table-driven streaming XML parsing methodology, called TDX. TDX expedites XML parsing by pre-recording the states of an XML parser in tabular form and by utilizing an efficient runtime streaming parsing engine based on a push-down automaton. The parsing tables are automatically produced from the XML schemas of a WSDL service description. Because the schema constraints are pre-encoded in a parsing table, the approach effectively implements a schema-specific XML parsing technique that combines parsing and validation into a single pass. This significantly increases the performance of XML Web services, which results in better response time and may reduce the impact of the flash-crowd effect. To implement TDX, we developed a parser construction toolkit to automatically construct parsers in C code from WSDLs and XML schemas. We applied the toolkit to an example Web services application and measured the raw performance compared to popular high-performance parsers written in C/C++, such as eXpat, gSOAP, and Xerces. The performance results show that TDX can be an order of magnitude faster. buy now

Run-Time Monitoring of Instances and Classes of Web Service Compositions

Fabio Barbon,Paolo Traverso,Marco Pistore,Michele Trainotti — 12/20/2006 14:48

The run-time monitoring of web service compositions has been widely acknowledged as a significant and challenging problem. In this paper, we propose a novel solution to the problem of monitoring web services implemented in BPEL. We devise an architecture that clearly separates the business logic of a web service from its monitoring functionality. The architecture supports both "instance monitors" that deal with the execution of a single instance of BPEL process, as well as "class monitors" that report aggregated information about all the instances of a BPEL process. We also define a language for the specification of instance and class monitors. The language allows for specifying boolean, statistic, and time-related properties. Finally, we devise a technique for the automatic translation of all these kinds of monitors to Java programs. buy now

Compressing SOAP Messages by using Pushdown Automata

Christian Werner,Carsten Buschmann,Ylva Brandt,Stefan Fischer — 12/20/2006 14:18

In environments with limited network bandwidth or resource-constrained computing devices the high amount of protocol overhead caused by SOAP is disadvantageous. Therefore, recent research work concentrated on more compact, binary representations of XML data. However, due to the special characteristics of SOAP communication most of these approaches are not applicable in the field of web services. First, we give a detailed overview of the latest developments in the field of XML data compression. Then we will introduce a new approach for compressing SOAP data which utilizes information on the structure of the data from an XML Schema or WSDL document to generate a single custom pushdown automaton. This cannot only be used as a highly efficient validating parser but also as a compressor: its transitions are tagged with short binary identifiers which replace XML tags during compression. This approach leads to extremely compact data representations as well as low memory and CPU utilization. Buy now

SEMAPLAN: Combining Planning with Semantic Matching to Achieve Web Service Composition

12/20/2006 14:18

In this paper, we present a novel algorithm to compose Web services in the presence of semantic ambiguity by combining semantic matching and AI planning algorithms. Specifically, we use cues from domain-independent and domain-specific ontologies to compute an overall semantic similarity score between ambiguous terms. This semantic similarity score is used by AI planning algorithms to guide the searching process when composing services. Experimental results indicate that planning with semantic matching produces better results than planning or semantic matching alone. The solution is suitable for semi-automated composition tools or directory browsers. buy now

Message from the General Chairs

12/15/2006 13:56

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.89

Program Committee

12/15/2006 14:24

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.106

User Feedback-Based Refinement for Web Services Retrieval using Multiple Instance Learning

Yanzhen Zou,Liangjie Zhang,Lu Zhang,Bing Xie,Hong Mei — 12/15/2006 14:49

A critical step in the process of reusing existing WSDLspecified components is the discovery of potentially relevant Web Services. Traditional category based Web Service retrieval usually can achieve good recall but worse precision because some semantically relevant Web Services are not actually relevant as they cannot provide suitable interfaces. In this paper, we present an interactive Web Services retrieval mechanism to refine the coarse retrieval results set in category based retrieval. In the refinement, the signature matching of Web Services that concerning the structure of operation specifications is investigated from a multi-instances view. In detail, each Web Service is represented as a bag in multiple instance learning, while each operation in this Web Service is regarded as an instance. This representation lies in that a user regards a service as useful if at least one operation provided by this Web Service is useful. Experimental results show that our approach can improve the retrieval performance significantly: It can gain 83% precision in average after two rounds of user relevance feedback.buy now

Process Mining, Discovery, and Integration using Distance Measures

Joonsoo Bae,Ling Liu,James Caverlee,William B. Rouse — 1/10/2007 20:34

Business processes continue to play an important role in today’s service-oriented enterprise computing systems. Mining, discovering, and integrating processoriented services has attracted growing attention in the recent year. In this paper we present a quantitative approach to modeling and capturing the similarity and dissimilarity between different process designs. We derive the similarity measures by analyzing the process dependency graphs of the participating workflow processes. We first convert each process dependency graph into a normalized process matrix. Then we calculate the metric space distance between the normalized matrices. This distance measure can be used as a quantitative and qualitative tool in process mining, process merging, and process clustering, and ultimately it can reduce or minimize the costs involved in design, analysis, and evolution of workflow systems. buy now

Security Conscious Web Service Composition

Barbara Carminati,Elena Ferrari,Patrick C. K. Hung — 12/20/2006 11:07

A Web service is a software system designed to support interoperable application-to-application interactions over the Internet. Web services are based on a set of XML standards, such as Web Services Description Language (WSDL), Simple Object Access Protocol (SOAP) and Universal Description, Discovery and Integration (UDDI). Recently, there has been a growing interest in Web service composition, and some languages (e.g., WSBPEL, BPML) for modeling the composition have been proposed. In this paper, we focus on security constraints of Web service composition, which have not been deeply investigated so far. We propose a method for modeling security constraints and a brokered architecture to build composite Web services according to the specified security constraints.buy now

Representation, Verification, and Computation of Timed Properties in Web

Raman Kazhamiakin,Paritosh Pandya,Marco Pistore — 1/10/2007 20:39

In this paper we address the problem of qualitative and quantitative analysis of timing aspects of Web service compositions defined as a set of BPEL4WS processes. We introduce a formalism, called Web Service Timed State Transition Systems (WSTTS), to capture the timed behavior of the composite web services. We also exploit an interval temporal logic to express complex timed assumptions and requirements on the system’s behavior. Building on top of this formalization, we provide techniques and tools for modelchecking BPEL4WS compositions against time-related requirements. We also present a symbolic algorithm that can be used to compute duration bounds of behavioral intervals that satisfy such requirements. We perform a preliminary experimental evaluation of our approach and tools with the help of an e-Government case study. buy now

Service Congestion: The Problem, and an Optimized Service Composition Architecture as a Solution

Hans Albrecht Schmid — 12/15/2006 14:17

Web services have many important advantages. But their great drawback, the invocation overhead, has not been a research focus. So far, only invocations of simple Web services were considered. But Web service composition may create additional performance problems. Our measurements demonstrate that Web service composition may reduce the maximal load of a system drastically. The reduction quotient increases quasi-exponentially with the number of service compositions. We call that phenomenon "service congestion" since it is not due to the combined payload of the composed services. Such detrimental performance effects can not be tolerated in many areas. For that reason, we propose an optimized service composition architecture as a solution. This service component architecture uses service connectors on top of standard Web service middleware. It optimizes automatically the local invocation of services with a Lookup & Service bus. The result is that no service congestion occurs since local service invocations have the cost of local calls.buy now

WIP: Web Service Initiation Protocol for Multimedia and Voice Communication over IP

Wu Chou,Li Li,Feng Liu — 12/15/2006 14:18

In this paper, we present WIP - Web Service Initiation Protocol for multimedia and voice communication over IP. WIP is an entirely web service based communication protocol, consisting of a set of web service operations for initiating and establishing converged (e.g. multimedia, IM, voice, etc.) communication services over IP. It inherits the principle of separation signaling and media transmission of SIP (Session Initiation Protocol); but it relies on a single web service stack to provide a full featured communication signaling protocol. WIP opens a new paradigm of web service based VoIP communication, which is extensible and can be easily integrated in end-to-end SOA solutions. The generic web service approach used in WIP overcomes many limitations which would be otherwise difficult to achieve in non-web service based communication methods used today. WIP is based on two-way, full duplex web service interaction. The communication signaling establishment in WIP is through web service interactions, and the media negotiation in WIP is modeled as a special web service "event" subscription, which is fully extensible for various media needs. The signaling messages of WIP are encoded in the standard based SOAP message envelops which can be carried by multiple transport protocols, including HTTP. WIP supports both P2P (peer-to-peer) and B2B (back-to-back) broker mode communication services. A prototype research system has been implemented, and the results indicate that WIP, as a full web service based communication protocol, is both feasible and advantageous.buy now

Communication Web Services Composition and Integration

Claudio Venezia,Paolo Falcarin — 12/15/2006 14:19

Nowadays, the development of services that span over both the Internet and telephony networks is driving significant efforts towards the integration of services offered by IT providers with telecom operators ones .Web Services have often been recommended for providing, composing and realizing Telecom services but introducing them means facing up with several challenges. This work sharpens benefits and drawbacks of Web Service applications within a Telecom environment focusing in particular on JAIN SLEE architecture, which defines a standard environment targeted at communication-based applications..buy now

Investigating Web Services Composition Applied to Network Management

12/15/2006 14:20

The composition of network management information is a feature widely required but poorly supported in traditional management technologies. Recently, Web services for network management has been enabling the investigation of more sophisticate management solutions, even though some concerns related to the Web services performance have been initially exposed, but quickly disappeared after the first research results. In this paper we show that Web services technologies have more to offer to the network management discipline than just bridging established network management protocols and Web services protocols. Particularly we explore the possibility of using Web services composition applied to network management. If successful, Web services composition can bring to network management the solution for some key problems yet to be solved, such as retrieving the information from several different devices and yet being able to use a simple and fast interface at the manager side. We present Web services composition for network management considering two approaches: in the first one a single network device needs to be contacted and its information composed; in the second one, many devices need to be contacted and the information retrieved from them need to be composed. We show that using proper tools we can not only really use Web services composition for network management, but also that such use can be integrated with traditional management technologies that are unlike to be abandoned in short and mid terms.buy now

Composing Business Processes with Partial Observable Problem Space in Web Services Environments

Yuhong Yan,Yong Liang,Han Liang — 12/15/2006 14:22

Composing business processes from individual services can be viewed as a planning problem in which a planner determines the execution orders of services in a process. Most existing Web Service composition research considers connecting Web Services into a business process. We argue that most existing Web Services are informative Web Services that are not the actual business services, but give the parameters of their correspondent business services. The planning problem is not only to select the proper business services, but also to determine the parameters of the business services which affect the ordering of the business services. Furthermore, it is not possible to extract all information from informative Web Services through queries. The planner has to work with the problem space that is not fully enumerable. This paper presents a method to optimize planning results with incompletely observed problem space. Genetic Algorithms (GA) help to navigate the incompletely observed problem space. At each loop of GA, Web Service data are queried and a new sub problem space is built. The planner works with the sub problem space and calculates all feasible plans. The plans are evaluated by GA in fitness function and the best plans are kept for the next loop of GA. The fitness function of GA reflects domain-dependent user preferences. The selected final plan is an optimized feasible plan though global optimization is not guaranteed.buy now

Technical Steering Committee

12/15/2006 14:22

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.129

Adaptation inWeb Service Composition and Execution

Girish Chafle,Koustuv Dasgupta,Arun Kumar,Sumit Mittal,Biplav Srivastava — 12/15/2006 14:25

Web services simplify enterprise application integration by facilitating reuse of existing components for creating new services. In a dynamic environment, it is imperative to design a Web Service Composition and Execution (WSCE) system that adapts to failure of component services or changes in their QoS offerings. In this paper, we motivate a staged approach for adaptive WSCE (A-WSCE) that cleanly separates the functional and non-functional requirements of a new service, and enables different environmental changes to be absorbed at different stages of composition and execution. We use Synthy, a prototype service creation environment, to implement our solution and demonstrate its effectiveness.buy now

Process Guided Service Composition in Building SoA Solutions:A Data Driven Approach

Wei Tan,Zhong Tian,Fangyan Rao,Li Wang,Ru Fang — 12/15/2006 14:28

Solution design has been more of an art than an engineering discipline. Lots of researchers and practitioners have proposed and exercised different kinds of approaches with varied success. Most of these methods seem to have focused on building new solutions from scratch. However, enterprise solutions today are mostly built on top of an existing IT infrastructure. The notion of SoA is trying to pave a way to integrate heterogeneous components together to meet new business needs. When a new requirement is given to a system developer in the form of business processes, it would be ideal if s/he can make the best of existing services for many reasons. In this paper we propose a data driven approach to provide service composition guidance to implement the given requirement. Based on the relations among business domain data and service domain data, we can generate additional data mediations according to three composition rules. With these data relations and composition rules, we give a formal approach to devise choreography of services from current service portfolio, plus additional data mediation artifacts to realize a given requirement. Our work can be seen as an effort to bridge the gap between business and service domain.buy now

A Web Services Secure Conversation Establishment Protocol Based on Forwarded Trust

Jun Wang — 12/15/2006 14:28

In large distributed monitoring and management systems that involve a large number of entities across multiple trust domains, the problem of establishing a secure conversation effectively between any two entities is outstanding when these two entities do not have a direct trust relationship. In this paper, we present a conversation establishment protocol that uses forwarded trust relationships to solve this problem. In this protocol, Security Assertion Markup Language (SAML) based Authentication assertions are used to encapsulate the conversation context as well as the conversation target identity authentication information into a secure context token. Our protocol is conformant to the emerging Web services standards of WS-Trust and WSSecureConversation. The implementation of this framework on Java platform and its application to secure a Web services based Grid monitoring system are presented.buy now

Preventing Service Oriented Denial of Service (PreSODoS): A Proposed Approach

Srinivas Padmanabhuni,Vineet Singh,K M Senthil Kumar,Abhishek Chatterjee — 12/15/2006 14:29

Today Web services have grown in context of both business to business (B2B) and business to customer (B2C) applications. Web services are the most popular mode of implementing Service Oriented Architecture (SOA). With this growth and acceptance in the industry, the role of security is crucial. Most of the existing security mechanisms in Web services like XML encryption[4], digital signatures[3], user tokens etc. provide security on one basic assumption that source of the request is legitimate. But a typical Denial of Service attacker can use these sources as reflectors and play around with the contents of a Web service body to create an attack scenario. In this paper, we propose PreSODoS - a framework to detect and prevent XML based Denial of Service (XDoS) attacks on Web services based applications. The framework relies on content introspection to detect any XDoS possibility. We use a Patricia Trie based representation so that the schemas and the request messages can be compared and validated in a performance efficient manner. PreSODoS is capable of detecting any repetitive request message and sense an attack scenario and trigger corresponding prevention mechanisms. buy now

Adding Authentication to Model Driven Security

Fumiko Satoh,Yuichi Nakamura,Koichi Ono — 12/15/2006 14:31

As Service-Oriented Architecture has become popular, security has been a critical issue in multiple security domains using the WS-Security framework. The authentication requirements depend on the application semantics, but configuring authentication is very difficult for someone who is not a security expert, such as an application developer, because it is necessary to understand platform-specific security features and authentication mechanisms. To resolve these difficulties, we propose a framework for platformindependent security configuration based on the Model Driven Architecture. In this paper, we introduce a security qualifier, which is an abstract annotation for specifying authenticated identity on a platform-independent model, and a Security Infrastructure Model which is a model including the platform information required for creating security policies. These ideas make authentication configuration possible without understanding the platform-specific information, such as the federation of the security domain and the relationships of trust between the servers. Our framework allows a non-security expert to configure security easily. We show how to configure the authentication for an ID propagation scenario and discuss advantages of our framework compared to existing tools.buy now

Towards a Reliable Distributed Web Service Execution Engine

Xinfeng Ye — 12/15/2006 14:31

This paper presents an approach for providing a reliable distributed Web Service Execution Engine. Instead of using a Web Service Execution Engine running on a single host to conduct the execution of a composite service, the responsibility of conducting the execution of the composite service has been delegated to the service providers that are chosen to provide the main functionalities of the tasks in the composite service. The operations of the tasks are represented as a set of XML-based notations. The notations are platform independent. Thus, they can be (a) retrieved by service providers based on different platforms, and, (b) interpreted and executed by the service providers. The approach also provides a mechanism for coping with possible failure in the system.buy now

High Performance Web Services Based on Service-Specific SOAP Processor

Lei Li,Chunlei Niu,Ningjiang Chen,Jun Wei — 12/15/2006 14:35

Web services, with an emphasis on open standards and flexibility, can provide benefits over existing capital markets integration practices. However, Web services must first meet certain technical requirements including performance, security and so on. SOAP, based on Extensible Markup Language (XML), inherits not only the advantages of XML, but its relatively poor performance. This makes SOAP a poor choice for many highperformance web services. In this paper, we propose a new approach to improve Web services performance. Focusing on avoiding traditional XML parsing and Java reflection at runtime, we create a service-specific SOAP processor to accelerate execution. Through our experiments in this paper, we observed that our approach obtained about a treble performance gain (maximum) by incorporating the SOAP processor into the SOAP engine.buy now

Panel Session 4: Mobile Web Services Trend Perspectives

12/15/2006 14:35

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.101

Analysis of Transport Optimization Techniques

Kevin J. Ma,Radim Bartos — 12/15/2006 14:36

The popularity of Web-based transactions and the need for more sophisticated content distribution methods has helped to fuel the rapid growth of Web Service adoption, specifically, HTTP-bound Web Services. Secure and efficient content delivery has long been a requirement of traditional Web-based distribution schemes, and existing the Web infrastructure provides numerous options for securing and optimizing HTTP. Two exemplary technologies are SSL/TLS and HTTP compression. While efforts to solidify the more granular WSSecurity standards are ongoing, and methods for XML message compression schemes continue to be investigated, HTTP provides an interim solution, supporting transactional security and message compression. The SSL/TLS and HTTP compression technologies have become commoditized and pervasive. And with the trend in content delivery toward hardware offload for these functions, modern data centers have begun to raise the bar for performance. In this paper, we examine three different paradigms for implementing SSL/TLS and HTTP compression: softwarebased functionality, server-resident hardware accelerators, and centralized network-resident hardware accelerators. We discuss the trade-offs between the two different offload techniques (i.e., PCI accelerator vs. network proxy) and explore their relationship to the current performance activities, in the field of Web Services. In analyzing the results for SSL/TLS offload, and the effects of compression, in conjunction with SSL/TLS, we draw parallels with the efforts of WS-Security and XML message compression. Although optimizations for software-based cryptography will continue to advance, the potential for hardware-based acceleration should not be overlooked. We discuss our results and address deployment scenarios for optimizingWeb-based transactions, and the future optimization of Web Service transactions.buy now

A Quality- and Cost-based Selection Model for Multimedia Service Composition in Mobile Environments

Wolf-Tilo Balke,Jorg Diederich — 1/10/2007 20:44

When moving from monolithic applications towards service-oriented multimedia frameworks, the composition of Web services to form complex multimedia workflows becomes a demanding problem. Especially mobile devices require a flexible composition strategy as they often have to move computationally complex or power-demanding tasks to powerful servers. Such a strategy also has to consider the changing environment due to movements of the device and it has to adapt to device-specific characteristics, e.g., the current battery level. Hence, mobile devices experience problems beyond the mere question of services’ availability or successful execution. We propose the E2Mon algorithm that monitors the execution chain of Web services and gracefully recovers from failures of individual services and network-specific or device-specific alarms. The sophisticated control flow dynamically chooses the quality-optimal and cost-optimal composition of available services handling both successive and parallel service execution. buy now

TARGET: Two-way Web Service Router Gateway

Feng Liu,Gesan Wang,Wu Chou,Lookman Fazal,Li Li — 1/10/2007 20:53

In this paper, we present the approach and architecture of TARGET: Two-way Web Service Router Gateway, for two-way web service interaction crossing enterprise domain and firewall. It provides a full support for asynchronous outbound operation and event notification in communication services. TARGET addresses an acute issue for internet applications that today’s enterprise NATs and firewalls only allow outbound HTTP request from the inside to the outside and block any request from the outside to the inside, which is a serious problem for two-way web services. TARGET is a generic solution to allow two-way web service interaction to traverse legitimately through NATs and strictly configured firewalls; and it is based on two-way SOAP message tunneling, service local registry, and service routing to bridge two-way web service interaction. A research TARGET system has been implemented and applied to real time communication services, e.g. conferencing. Extensive experiments on TARGET are performed, and its performance with various sizes of SOAP messages is studied. The applicability and feasibility of TARGET for two-way web service interaction is verified. buy now

On Encrypting and Signing Binary XML Messages in the Wireless Environment

Jaakko Kangasharju,Tancred Lindholm,Sasu Tarkoma — 12/15/2006 14:39

In the wireless world there has recently been much interest in alternate serialization formats for XML data, mostly driven by the weak capabilities of both devices and networks. However, an alternate serialization format is not easily made compatible with XML security features such as encryption and signing. We consider here ways to integrate an alternate format with security, and present a solution that we see as a viable alternative. In addition to this, we present extensive performance measurements, including ones on a mobile phone, on the effect of an alternate format when using XML-based security. These measurements indicate that, in the wireless world, reducing message sizes is the most pressing concern, and that processing efficiency gains of an alternate format are a much lesser concern.buy now

Measuring Privacy Protection in Web Services

George Yee — 12/20/2006 10:58

The growth of the Internet has been accompanied by the growth of web services (e.g. e-commerce, ehealth) leading to the need to protect the personal privacy of web service users. However, it is also important to be able to measure a web service in terms of how well it protects personal privacy. Such a capability would benefit both users and developers. Users would benefit from being able to choose (assuming that such measures were made public) the service that has the greatest ability to protect user privacy (this would in turn encourage web service providers to pay more attention to privacy). Developers would benefit by being able to incrementally measure and modify their services during development until certain target levels of privacy protection are reached. This paper presents an approach for measuring how well a web service protects personal privacy and illustrates the approach with an example.buy now

A Framework for Building Privacy-Conscious Composite Web Services

Wei Xu,V.N. Venkatakrishnan,R. Sekar,I.V. Ramakrishnan — 12/20/2006 11:04

The rapid growth of web applications has prompted increasing interest in the area of composite web services that involve several service providers. The potential for such composite web services can be realized only if consumer privacy concerns are satisfactorily addressed. In this paper, we propose a framework that addresses consumer privacy concerns in the context of highly customizable composite web services. Our approach involves service producers exchanging their terms-of-use with consumers in the form of "models". Our framework provides automated techniques for checking these models at the consumer site for compliance of consumer privacy policies. In the event of a policy violation, our framework supports automatic generation of "obligations" that the consumer generates for the composite service. These obligations are automatically enforced through a dynamic program analysis approach on the web service composition code. We illustrate our approach with the implementation of two example services.buy now

Expressing and Reasoning about Service Contracts in Service-Oriented Computing

1/10/2007 21:07

The Web Services and Service-Oriented Architectures (SOA) vision [6] is about building large-scale distributed applications by composing coarse-grained autonomous services in a flexible architecture that can adapt to changing business requirements. These services interact by exchanging one-way messages through standardised message processing and transport protocols. This vision is being driven by economic imperatives for integration and automation across administrative and organisational boundaries. Service contracts play a critical role in SOA. They describe the functionality a service exposes to other services on the network. A contract defines the outgoing and incoming messages the service can send and receive, and the order in which they are sent and received (messaging behaviour). It provides developers and tools with the metadata to compose services into service-oriented applications. This paper presents a concise yet expressive model for service contracts to describe messaging behaviour. The idea is simple: we use Boolean conditions to specify when a message can be sent and received, where the conditions refer only to other messages in the service contract that is, conditions only refer to a service’s externalised messaging state and not to internal state. buy now

Situated Web Service: Context-Aware Approach to High-Speed Web Service Communication

Ikuo Matsumura,Toru Ishida,Yohei Murakami,Yoshiyuki Fujishiro — 12/20/2006 16:38

A framework is proposed to improve Web Service performance based on context-aware communication. Two key ideas are introduced to represent a client context; (1) available protocols that the client can handle, and (2) operation usage that shows how the client uses Web Service operations. We call our context aware approach a Situated Web Service (SiWS). We implemented and evaluated the SiWS and found that the overall performance was improved if more than three Web Services were executed between context changes. buy now

Analyzing XML Parser Memory Characteristics: Experiments towards ImprovingWeb Services Performance

Gang WANG,Cheng XU,Ying LI,Ying CHEN — 1/10/2007 21:25

XML plays an important role in building enterprise applications. However, most of the XML-based applications, particularly the emerging web services, suffer from low performance caused by XML processing and thus bring negative user experience in terms of response time. We argue that by reducing the considerable overhead in garbage collection the XML processing performance can be improved. We begin by conducting a set of experiments to understand the XML parser’s memory characteristics, such as heap composition, object size and type distributions, object lifetime, and so on. Then, we get the valuable findings for improving performance that XML processing, which violates the weak generational hypothesis, is an memory allocation intensive workload in which most objects are small and long-lived. The findings can benefit the design of XML parsing specific GC and related tools designed to improve XML processing performance for web services. buy now

Improving the performance of XML based technologies by caching and reusing information

Francesco Lelli,Gaetano Maron,Salvatore Orlando — 12/20/2006 16:43

The growing synergy between Web Services and Gridbased technologies is enabling profound, dynamic interactions between applications dispersed in geographic, institutional, and conceptual space. Such deep interoperability requires the simplicity, robustness, and extensibility for which XML has been conceived, making it a natural lingua franca for the network. Along with these advantages, there is a degree of inefficiency that may limit the applicability of XML. Firstly, we investigate the limitations of XML for highperformance and high-interactive distributed computing. Our experimental results clearly show that focusing on parsers, that are routinely used for desterilize XML messages exchanged in these system, we can improve the performance of a generic the end to end web services based solution. Secondly we present a new parser, the Cache Parser, which uses a cache to reduce the parsing time sender and receiver side, by reusing information related to previously parsed documents/messages similar to the one under examination. Finally, we will show how our fast parser can improve the global throughput of any application based on Web or Grid Services, or also JAXP-RPC. Experimental results demonstrate that our algorithm is 25 times faster than the fastest algorithm in the market and, if used in a WS scenario, can dramatically increase the number of requests per second handled by a server (up to 150% of improvement) bringing it close to a system that does not use xml at all. buy now

Mapping Service Level Agreements in 3-tier settings

Siva Gurumurth,Parul A. Mittal,Amit A. Nanavati,Dipanjan Chakraborty — 1/10/2007 21:40

A telecom operator ("service provider",SP) offers various services to subscribed customers by partnering with various third party providers ("content provider",CP). The SP acts as a liaison between subscribers and partners. One of the main functions of the SP, therefore, is to match the "demand" of the subscribers with the "supply" of the CPs. Such a matching is a prerequisite for efficient service selection while ensuring customer satisfaction, and is useful for optimisation, such as resource allocation and load balancing. The "demand" requirements and "supply" guarantees can be concretized using Service Level Agreements (SLAs). SLAs can be expressed formally using standards such as WSLA or WS-Agreement. We present a system that automates the task of finding a matching between these two sets, subscriber-SP and SP-CP, of SLAs. First, the SLAs are normalised to a common denominator, then composed if required, and finally the matching engine computes and outputs the map. The matching algorithm, which is of central importance, compares logical expressions involving predicates. The logical expressions are first converted into CNFform, and instead of naive O(m × n) comparisons, we develop a more efficient approach to solve the problem. As a proof-of-concept, we have implemented a prototype as an Eclipse plugin. buy now

Toward UML Profiles for Web Services and their Extra-Functional Properties

Guadalupe Ortiz,Juan Hern??ndez — 12/20/2006 17:22

Web Service technologies offer a successful way for interoperability among applications. Now it is important to face how to model systems based on service functionality and also how to add extra-functional properties to them. This is the reason why we propose first of all a versatile and simple UML profile based on the Service Component Architecture specification for modeling services and, secondly, a new UML profile is proposed in order to model and reuse extra-functional properties in the named models. Besides, the property profile provides enough information to enable property code and description generation at a later stage. buy now

Early Capacity Testing of an Enterprise Service Bus

Ken Ueno,Michiaki Tatsubori — 1/10/2007 21:33

An enterprise service-oriented architecture is typically realized on a messaging infrastructure called an Enterprise Service Bus (ESB). An ESB is a bus which delivers messages from service requesters to service providers. Since it sits between the service requesters and providers, it is not appropriate to use any existing capacity planning methodology for servers, such as modeling, to estimate an ESB’s capacity. There are programs which run on an ESB called mediation modules. Their functionalities vary and depend on how people use the ESB. This creates difficulties for capacity planning and performance evaluation. This paper proposes a performance evaluation methodology and techniques for ESBs. We actually run the ESB on a real machine while providing a pseudo-environment around it. In order to ease setting up the environment we provide ultra-light service requestors and service providers for the ESB under test. We show that the proposed mock environment can be set up with practical hardware resources available at the time of hardware resource assessment. Our experimental results showed that the testing results with our mock environment are equivalent to the results in the real environment. buy now

Exploring Perturbation Based Testing for Web Services

Lourival F. Júnior de Almeida,Silvia R. Vergilio — 2/06/2007 21:43

Web Service is a modern technology commonly used to integrate software projects among different platforms, operating systems or even programming languages. This distributed and heterogeneous nature complicates the testing activity which is, in general, expensive and effort demanding. Adequate and cost effective testing methods are needed for Web Services. An extended approach based on XML messages perturbation has been introduced to test pairs of Web Services. Perturbation operators produce modified XML messages, which are used as test cases. This work explores the use of such promising approach by introducing new perturbation operators for SOAP messages and describing a supporting tool, named SMAT-WS. An experimental study was accomplished with this tool. The obtained results allow an evaluation of the perturbation operators regarding cost and efficacy.buy now

An Approach to Exception Handling for Service-Oriented Systems

Yue Qiang,Wang Hao,Zha Li,Li Wei,Xu Zhi-wei — 12/20/2006 11:15

This paper sets out key issues of exception handling that relate to identifying, analyzing and dealing with an exception in service-oriented systems. Then required concepts, basic structures and algorithms for the Ml-Eh are discussed. The new concepts include the super-space of exception definitions, the meta-definition mode, and components in an exception message. The main characteristics of the Ml-Eh are a uniform definition mode, dynamical extensibility, and abilities of configurable analyses and encapsulations, and a message-level combination. Finally, implementation and evaluation of the mechanism is given. buy now

A Flexible and Efficient Approach to Reconcile Different Web Services-based Event Notification Specifications

Yi Huang,Dennis Gannon — 12/20/2006 11:16

Event notification plays an important role in the orchestration of distributed systems. Web services-based event notification is an important step to achieve an interoperable messaging system on the Internet scale. However, different incompatible specifications have been proposed to specify the Web services interfaces for Web services-based event notification systems. The WS-Eventing specification and the WS-Notification specifications are two major initiatives. WSMessenger is our implementation of both specifications. A mediation approach is used to reconcile the differences between these two specifications. In this paper, we propose a "Normalization-Processing-Customization" (NPC) model for mediation among competing Web services and show how this model is used in WS-Messenger to reconcile the incompatibility between these two specifications. The NPC model is flexible and scalable. The mediation implementation in WS-Messenger is efficient with a very small overhead.buy now

Using constraint hierarchies to support QoS-guided service composition

Ying Guan,Aditya K. Ghose,Zheng Lu — 12/20/2006 11:17

A key impediment to the widespread adoption of web services is the is the relatively limited set of tools available to deal with Quality-of-Service (QoS) factors [12]. QoS factors pose several difficult challenges in how they may be articulated. While the functional requirements of a service can be represented as predicates to be satisfied by the target system, QoS factors are effectively statements of objectives to be maximized or minimized. QoS requirements occur naturally as local specifications of preference. Dealing with QoS factors is therefore a multi-objective optimization problem. In effect, these objectives are never fully satisfied, but satisficed to varying degrees. In evaluating alternative design decisions, we need to trade-off varying degrees of satisfaction of potentially mutually contradictory non-functional requirements. One key contribution of this work is the use of the constraint hierarchies framework from hierarchical constraint logic programming framework in dealing with Quality of Service(QoS) factors . We show how QoS factors can be formulated as soft constraints and how the machinery associated with constraint hierarchies can be used to evaluate the alternative trade-offs involved in seeking to satisfy a set of QoS factors that might pull in different directions. We apply also this approach to the problem of reasoning about web service selection and composition, and establish that significant value can be derived from such an exercise.buy now

Implementing a Flexible Compensation Mechanism for Business Processes in Web Service Environment

Zaihan Yang,Chengfei Liu — 12/20/2006 11:18

Web services have been emerging as a promising technology for business process integrations. Due to their long-duration and loosely coupled properties, Web service based applications require transactional support beyond traditional transactions. Some web service standards have been proposed to deal with the transaction aspect of Web service applications. Compensation is a commonly used mechanism in these standards for backward recovery. However, the compensation mechanism usually adopted is too fixed and cannot satisfy the various requirements of different applications. In this paper, we first analyse the compensation protocol of current standards. Then we enrich the protocol by allowing flexible compensation and extend our proposed multiple-compensation mechanism in web service environment. The implementation of the extended compensation mechanism is discussed and the incorporation of the mechanism into current standards is also addressed.buy now

Dynamic Regeneration of Workflow Specification with Access Control Requirements in MANET

Casey K. Fung,Patrick C. K. Hung,William M. Kearns,Stephen A. Uczekaj — 12/20/2006 11:19

Distributed software systems are the basis for innovative applications. The key for achieving survivable and maintainable distributed systems is agility because the nondeterministic nature of distribution would otherwise leave the system uncontrollable, especially in emerging mobile ad-hoc networks. A mobile ad-hoc network (MANET) is based on a self-organizing and rapidly deployed network of mobile services to collaborate without using any pre-existing fixed network infrastructure. Survivability is defined as the capability of a service to fulfill its mission in a timely manner, even in the presence of attacks, failures, or accidents. There are four key survivability properties: resistance, recognition, recovery and adaptation. Recovery, a hallmark of survivability, is the capability to maintain critical components and resource during attack, limit the extent of damage, and restore full services following attack. Exception handling is a way to deals with the recovery aspect of survivability. Resistance can be viewed as the process of limiting access to critical and vulnerable resources only to authorized users, programs, processes, or other systems. This paper bridges the analysis of secure business process and its recovery aspect in terms of exception handling in the context of access control requirements. We propose an integrated approach to engineer a survivable distributed system through dynamic regeneration of workflow specifications in the context of Business Process Execution Language for Web Services (BPEL) and eXtensible Access Control Markup Language (XACML).buy now

E Role-based Decomposition of Business Processes using BPEL

Rania Khalaf,Frank Leymann — 12/20/2006 11:20

This paper addresses role-based decomposition of a business process model (based on a subset of WS-BPEL, using explicit data link)s. A mechanism is presented for partitioning a business process so that each partition can be enacted by a different participant. An important goal is to disconnect the partitioning itself from the design of the business process, simplifying the reassignment of activities to different entities. The result is several (compliant) BPEL processes, one for each participant, as well as the information needed to wire them together at deployment time and ensuring correct instance-level connections at runtime. We present details of partitioning and successfully running a sample process with three participants.buy now

Differential QoS support in Web Services Management

Abdelkarim Erradi,Srinivas Padmanabhuni,Niranjan Varadharajan — 1/10/2007 21:56

The variation of contexts in which a Web service could be used and the resulting variation in Quality of Service (QoS) expectations makes a clear case for further research to extend Web services management platforms with more sophisticated control mechanisms to cater for differentiated service offerings. However, most Web services platforms are based on a best-effort model, which treats all requests uniformly, without any type of service differentiation or prioritization. This paper presents WS-DiffServ, a service differentiation middleware based on prioritization which leverages service requestor profile to classify service requests. We first explore the typical generic requirements of a differential QoS support in Web services management. We then present in detail the design of a priority based differentiated responsiveness platform for Web services. buy now

A Model-driven WSDL Extension for Describing the QoS ofWeb Services

Andrea D’Ambrogio — 1/10/2007 22:07

Web services are the building blocks of the emerging computing paradigm based on service-oriented architectures. A web service is a self-describing, open component that supports rapid composition of distributed applications. Web service definitions are used to describe the service capabilities in terms of the operations of the service and the input and output messages for each operation. Such definitions are expressed in XML by use of the Web Service Definition Language (WSDL). Unfortunately, a WSDL description only addresses the functional aspects of a web service without containing any useful description of non-functional or quality of service (QoS) characteristics. This paper introduces a lightweight WSDL extension for the description of QoS characteristics of a web service. The extension is carried out as a metamodel transformation, according to principles and standards recommended by the Model Driven Architecture (MDA). The WSDL metamodel is introduced and then transformed into the Q-WSDL (QoS-enabled WSDL) metamodel. The proposed Q-WSDL extension can effectively be used to specify QoS requirements, to establish service level agreements (SLA), to add QoS-oriented characteristics when querying registries of web services and to support the automated mapping from WSDL documents to Q-WSDL ones and from UML models to Q-WSDL web services.buy now

QoS Explorer: A Tool for Exploring QoS in Composed Services

Conrad Hughes,Jamie Hillman — 12/20/2006 11:24

This paper presents QoS Explorer, an interactive tool we have developed which predicts quality of service (QoS) of a workflow from the QoS characteristics of its constituents, even when the relationships involved are complex. This facilitates design and instantiation of workflows to satisfy QoS constraints, as it enables the user to discover and focus effort on the aspects of a workflow which most affect their primary QoS concerns, thus improving efficiency of workflow development. Further, the underlying model we use is more sophisticated than those of similar recent work [13, 2, 18], and includes processing of entire statistical distributions and probabilistic states (instead of the simple numeric constants used elsewhere) to model such nonconstant variables as execution time.buy now

Business Process Development based on Web Services: a Web Information System for Medical Image Management and Processing

Valeria de Castro,Marcos López Sanz,Esperanza Marcos — 1/10/2007 22:12

Innovation in technologies such as XML and Web Services, has led to an interest in business processes. Consequently, several languages for the execution of business processes have been created. Nevertheless, as these languages cannot be used in the early stages of the development process of Web information systems (WIS), it is necessary to include methodologies that allow the systems analysts to understand the business process as well as to model the services composition. This work presents a process for the business process development based on Web Services, which starts with the identification of the services that will be offered to the user and ends with the definition of a service composition model. This process is illustrated by means of a WIS for the management of medical images that we have taken as a case study. Because it is one of the most widely used for Web services composition, we have chosen the BPEL4WS language for the implementation of the business processes. However, we have found several limitations in such language which are also described in this paper. buy now

Bootstrapping Performance and Dependability Attributes ofWeb Services

Florian Rosenberg,Christian Platzer,Schahram Dustdar — 12/20/2006 15:13

Recently, Web services gain momentum for developing flexible service-oriented architectures. Quality of service (QoS) issues are currently not part of the Web service standard stack, although non-functional attributes like performance, dependability or cost and payment play an important role for service discovery, selection, and composition. A lot of research is dedicated to different QoS models, at the same time omitting a way to specify how QoS parameters (esp. the performance related aspects) are assessed, evaluated and constantly monitored. Our contribution in this paper comprises a) an evaluation approach for QoS attributes of Web services, which works completely serviceand provider independent, b) a method to analyze Web service interactions by using our evaluation tool and extract important QoS information without any knowledge about the service implementation. Furthermore, our implementation allows assessing performance specific values (such as latency or service processing time) that usually require access to the server which hosts the service. The result of the evaluation process can be used to enrich existing Web service descriptions with a set of up-to-date QoS attributes, therefore, making it a valuable instrument for Web service selection. buy now

An SOA-based Framework for Instrument Management for Large-scale Observing Systems (USArray Case Study)

12/20/2006 11:27

Large-scale observing systems are poised to become the dominant means of study for a variety of natural phenomena. These systems are comprised of hundreds to thousands of instruments that must be queried, managed, and shared in a scalable fashion. Services-oriented architectures (SOAs) are widely recognized as the preferred framework for building scalable and extensible cyberinfrastructure. By applying SOA concepts, we created a framework for organizing observing system resources. Guided by this framework, we developed web services, custom workflow applications, and an integrated user interface of monitors and controls for managing instruments in large-scale sensor network observing systems. In this paper we present our approach and discuss its application to the NSF EarthScope USArray large-scale seismic observing system.buy now

Opal: SimpleWeb Services Wrappers for Scientific Applications

12/20/2006 11:28

The Grid-based infrastructure enables large-scale scientific applications to be run on distributed resources and coupled in innovative ways. However, in practice, Grid resources are not very easy to use for the end-users who have to learn how to generate security credentials, stage inputs and outputs, access Grid-based schedulers, and install complex client software. There is an imminent need to provide transparent access to these resources so that the endusers are shielded from the complicated details, and free to concentrate on their domain science. Scientific applications wrapped as Web services alleviate some of these problems by hiding the complexities of the back-end security and computational infrastructure, only exposing a simple SOAP API that can be accessed programmatically by applicationspecific user interfaces. However, writing the application services that access Grid resources can be quite complicated, especially if it has to be replicated for every application. In this paper, we present Opal which is a toolkit for wrapping scientific applications as Web services in a matter of hours, providing features such as scheduling, standardsbased Grid security and data management in an easy-to-use and configurable manner.buy now

Axis2, Middleware for Next Generation Web Services

12/20/2006 11:32

Axis2, the next generation of Apache Web Services middleware, is an effort to re-architecture Apache Web Service stack to incorporate the changes in Web Services. Among many improvements, Axis2 provides first class Messaging and SOAP extension supports together with a novel lightweight streaming based XML processing Model. The architecture is build on top of a simple and extensible core that provides the basic abstractions for the rest of the system. We present the design and the thought process behind the key abstractions by breaking down the architecture in to three topics, XML Processing Model, Extensible SOAP processing model and Messaging Framework. This Paper explains the overall architecture while concentrating on the three topics, and demonstrate how they all fit together to yield Axis2.buy now

Service-Oriented Order-to-Cash Solution with Business RSS Information Exchange Framework

Liang-Jie Zhang,Abdul Allam,Cesar A. Gonzales — 2/05/2007 19:33

For period of time customers have demand for more reusable and manageable service-oriented components for Order-to-Cash (O2C) solution so they can be easily re-configured and managed to adapt to business changes quickly. In this paper, we present a serviceoriented business process optimization model that minimizes potential revenue leakage through process improvements. We introduce service componentization approach to decompose business processes to identify re-usable services in SOA solution context. We adopt Really-Simple-Syndication (RSS) technology to realize a collaborative dispute management solution based on Service-Oriented Architecture (SOA). The proposed approach can help streamline the dispute management process with revenue increase and higher customer satisfaction.buy now

O2C-ppt.pdf

Adapting Legacy Home Appliances to Home Network Systems UsingWeb Services

Masahide Nakamura,Akihiro Tanaka,Hiroshi Igaki,Haruaki Tamada,Ken-ichi Matsumoto — 12/20/2006 11:34

This paper presents a framework that adapts the conventional home electric appliances with the infrared remote controls (legacy appliances) to the emerging home network system (HNS). The proposed method extensively uses the concept of service-oriented architecture to improve programmable interoperability among multi-vendor appliances. We first prepare APIs that assist a PC to send infrared signals to the appliances. We then aggregate the APIs within self-contained service components, so that each of the component achieves a logical feature independent of device(or vendor)-specific operations. The service components are finally exported to the HNS as Web services. Thus, the legacy appliances can be used as distributed components with open interfaces. To demonstrate the effectiveness, we also implement an actual HNS and integrated services with multi-vendor legacy appliances.buy? now

Decomposition and Abstraction of Web Applications for Web Service Extraction and Composition

Michiaki Tatsubori,Kenichi Takashi — 12/20/2006 11:35

There are large demands for re-engineering humanoriented Web application systems for use as machineoriented Web application systems, which are called Web Services. This paper describes a framework named H2W, which can be used for constructing Web Service wrappers from existing, multi-paged Web applications. H2Ws contribution is mainly for service extraction, rather than for the widely studied problem of data extraction. For the framework, we propose a page-transition- based decomposition model and a page access abstraction model with context propagation. With the proposed decomposition and abstraction, developers can flexibly compose a Web Service wrapper oftheir intent by describing a simple worwow program incorporating the advantages of previous work on Web data extraction. We show three successful wrapper application examples with H2 W for real world Web applications.buy now

Decentralized Orchestration of CompositeWeb Services

Walter Binder,Ion Constantinescu,Boi Faltings — 12/20/2006 11:36

Traditional, centralized orchestration of composite web services often leads to inefficient routing of messages. To solve this problem, we present a novel scheme to execute composite web services in a fully decentralized way. We introduce service invocation triggers, a lightweight infrastructure that routes messages directly from the producing service to the consuming one, enabling fully decentralized orchestration. An evaluation confirms that decentralized orchestration can significantly reduce the network traffic when compared with centralized orchestration.buy now

A Two Steps Method For Analyzing Dependency of Business Services On IT Services Within A Service Life Cycle

Hong Cai — 12/20/2006 11:37

In order to meet the dynamic business environment, the alignment of business services and IT services has long been a challenge to both business and IT people. In this paper, a graph centric, two-phase analysis and design method for service system is proposed which is based on the recent evolutions in these fields like Service Oriented Architecture (SOA). The method proposed in this paper views a service system comprising of business services and IT services as a layered complex system and uses matrices to represent the interactions between different layers. The method could help decision makers to analyze the impact of service changes during service design period. This could also facilitate the design of a more flexible IT service system reacting to business changes. The aim of this paper is to seek balance among different parts of a service system, and to provide a holistic view of the system for different role players. Results from this paper could give service designers some insights on how to design an Enterprise Service Bus (ESB) in the SOA architecture of an enterprise.buy now

Towards Aspect-based Modeling of Self-Healing Web Services

G. Kouadri Most??faoui,Z. Maamar,N. C. Narendra,Ph. Thiran — 12/20/2006 11:39

The dynamic nature of the business world shows the continuous pressure to reduce expenses, increase revenues, and remain competitive. This calls for a rapid reaction to the market trends, a rapid handling of user needs, and a rapid understanding of forthcoming challenges. To support businesses in the process of reaching these goals, Web services need to be selfaware of the environment in which they operate and self-healing so they can recover to normal levels of operation after disturbances.buy now

Model Driven Design of Distribution Patterns forWeb Service Compositions

Ronan Barrett,Claus Pahl — 12/20/2006 11:41

Increasingly, distributed systems are being constructed by composing a number of components, often legacy applications exposed using Web service interfaces. There are a number of architectural configurations or distribution patterns, which express how such systems are to be deployed. However, the amount of code required to realise these distribution patterns is considerable. Here, we propose a novel Model Driven Architecture using UML 2.0, which takes existing Web service interfaces as its input and generates an executable Web service composition, based on a distribution pattern chosen by the software architect.buy now

A Formal Model forWeb Service Choreography Description Language (WS-CDL)

12/20/2006 11:42

We propose a language CDL as a formal model of simplified WS-CDL. The operational semantics of CDL is given, and static validation and verification of choreographies is studied. Some properties of the proposed model are verified using the SPIN model-checker, which illustrates the potential usage and benefits of the formal model.buy now

A Method for Formal Verification of Service Interoperability

Stanislav Pokraev,Dick Quartel,Maarten W. A. Steen,Manfred Reichert — 1/10/2007 22:17

Service interoperability is a major obstacle in realizing the SOA vision. Interoperability is the capability of multiple, autonomous and heterogeneous systems to use each other’s services effectively. It is about the meaningful sharing of functionality and information that leads to the achievement of a common goal. In this paper we identify requirements for semantic and pragmatic interoperability. We further propose a method for assessing whether a composite system meets these requirements. buy now

A Unified Approach for the Discovery of Web and Peer-to-Peer Services

M. Pantazoglou,A. Tsalgatidou,G. Athanasopoulos,T. Pilioura — 12/20/2006 11:47

As the web service technology matures, other computing paradigms such as peer-to-peer gradually adopt the service-oriented approach and are beginning to expose functionality as services. Hence there will soon be a need for integration of these heterogeneous services, for the development of service-oriented applications. The first step to accomplish this is to establish a unified approach for service discovery. In this paper, we briefly present a query language along with its enacting service search engine which is used for effectively discovering web and p2p services in a unified manner.buy now

Community-Based Service Discovery

Christopher A. Perryea,Sam Chung — 12/20/2006 11:48

This paper presents a novel approach to expedite a service discovery process. Since current service discovery approaches do not assume any preprocessing when service providers publish services into a service registry, service composition occurs at discovery time. Also, easily reusing a composed service for future discovery has not been considered. In this paper, instead of considering a service registry as a set of published services, we build a service knowledge base at publication time, which we call a service community. The service community consists of a set of service populations and their relationships in composition. A service population is a set of services in which the input and output parameters of all services are semantically equivalent. These pre-composed services will expedite the on demand service discovery process. Also a newly composed service is injected into the service community, and easily reused for future discoveries.buy now

Inferring, Validating, and Coordinating the Commitments in aWorkflow

Jiangbo Dang,Michael N. Huhns — 12/20/2006 11:49

A workflow can be represented as a set of Web services and a specification for the control and data flows among these services. It can also be represented as a colored Petri net (CPN), which is a graphical and mathematical modeling tool. In multiagent systems (MAS), a workflow is a dynamic set of tasks performed by a set of agents to reach a shared goal. We show herein that commitments among agents can be used to model a workflow and coordinate their execution of it. This paper presents methodologies to map an OWL-S model for a workflow to a CPN, and then to infer commitments and causal relationships from the CPN graph. With our methodologies, agents can collaboratively enact a workflow through commitment-based formalisms.buy now

ComposingWeb Services with Nondeterministic Behavior

Daniela Berardi,Giuseppe De Giacomo,Massimo Mecella,Diego Calvanese — 12/20/2006 11:50

The promise of Web services is to enable the composition of new distributed applications/solutions: when no available service can satisfy a client request, (parts of) available services can be composed and orchestrated in order to satisfy such a request. Service composition involves two different issues: the synthesis, in order to synthesize, either manually or automatically, a specification of how coordinating the component services to fulfill the client request, and the orchestration, i.e., how executing the previous obtained specification by suitably supervising and monitoring both the control flow and the data flow among the involved services.buy now

Grounding OWL-S in WSDL-S

Massimo Paolucci,Matthias Wagner — 12/20/2006 11:51

WSDL-S and OWL-S are semantic Web services languages that both aim at enriching WSDL with semantic annotation. In this paper, we analyze the similarities and differences between the two languages aiming at showing how OWL-S annotations could take advantage of WSDL-S annotations. In the process, we discover and analyze representational trade-offs between the two languages.buy now

Quantitative Trust Based on Actions

Chao Wang,Chi-Hung Chi — 12/20/2006 15:10

In this paper, we propose an automatic, self-adaptive trust model for component-based Service-Oriented Architecture that is based on Bayesian model. The focus of this model is the "quantitative trust on action". Both the computation model and its updating mechanism are given. Through our implementation of this model using Monte-Carlo algorithm, we show the feasibility and practicability of our proposal as well as its ability to rectify any unfair advertisement and to track the capability of highly dynamic service. buy now

Recovery Policies for Enhancing Web Services Reliability

Abdelkarim Erradi,Piyush Maheshwari,Vladimir Tosic — 12/20/2006 15:12

Web services are gaining acceptance as a standards-based approach for integrating loosely coupled services often distributed over a network. Hence, achieving high levels of reliability and availability in spite of service or infrastructure failures poses unique set of challenges. However, current Web services middleware provide limited constructs for specifying faults detection and recovery actions. Additionally, faults-handling logic often gets scattered and tangled with the service logic. Consequently, this negatively impacts maintainability and adaptability. To address these requirements for reliable and fault tolerant Web services execution, we propose a set extensible recovery policies to declaratively specify how to handle and recover from typical faults in Web services composition. The identified constructs were incorporated into a lightweight service management middleware named MASC (Manageable and Adaptive Service Composition) to transparently enact the fault management policies and facilitate the monitoring, configuration and control of managed services. Several experimental results with a service based supply chain management system illustrate the effectiveness of our approach to providing reliable and uninterrupted services. buy now

Fortified Web Services Contracts for Trusted Components

Avi Jencmen,Amiram Yehudai — 12/20/2006 11:53

Web services provide a standard means of interoperating between different software applications, running on a variety of platforms and/or frameworks. While the concepts of Web services are aimed at providing a standard means to support interoperable machine-to-machine interaction over a network, they do not solve the problem of trust between service requesters and providers. A Trusted Component is defined as a reusable software element possessing specified and guaranteed property qualities. The highly reusable nature of a Web service emphasizes the need for a "trust ensuring" mechanism between the requester and the provider of the service.buy now

Adaptive Service Agreement and Process Management

12/20/2006 11:54

The ASAPM project aims at developing new techniques, mechanisms and software solutions for enablement of flexible, dynamic and robust management of serviceoriented application provision processes to ensure collective functionality, end-to-end QoS and stateful coordination of complex services.buy now

Easy SOA: Rapid Prototyping environment withWeb Services for End Users

Takayuki Yamaizumi,Takashi Sakairi,Masaki Wakao,Hideaki Shinomi,Samuel Adams — 1/10/2007 22:24

This paper describes Easy SOA. Easy SOA is a rapid prototyping model for SOA based on Ad hoc Development and Integration tool for End Users (ADIEU). With ADIEU, end users can prototype their Web applications and Web Services rapidly by putting ’cards’ into a ’sheet’ constructed on a Web browser. Easy SOA realizes a prototype development model for Service Oriented Architecture (SOA) as well as for Web applications and Web Services using ADIEU. buy now

A Two-Layered Software Architecture for Distributed Workflow Coordination over Web Services

Janaka Balasooriya,Jaimini Joshi,Sushil K. Prasad,Shamkant Navathe — 12/20/2006 11:56

The current state of the art of workflows over web services employs a centralized composite process to coordinate the constituent web services. Therefore, the coordinator process is complex, less scalable, and bulky. This paper introduces an architecture and a technique for distributing the centralized coordination logic of traditional workflows by (i) extending the stateless web services into self-coordinating entities using coordinator proxy objects, and (ii) creating a workflow over these entities by interconnecting them into a distributed network of objects using web bond primitives. Previously, we have developed web bond primitives to enforce interdependencies among autonomous entities. We have designed and prototyped our BondFlow system, which provides a platform to configure such distributed workflows, producing coordination components with footprint small enough (around 150 KB) to be executed on a handheld.buy now

A Semantic Web Services Approach Towards Automated Software Engineering

Ulrich Dinger,Roy Oberhauser,Christian Reichel — 12/20/2006 12:01

The growing complexity of software, combined with demands for greater productivity and shorter cycles, creates an increasing demand for more automation and integration within the software engineering (SE) domain. When viewed holistically, the heterogeneous nature, implicit feature cross-dependencies, and manual administration of the toolchain infrastructure results in unnecessary complexity, inefficiencies, and reduced reliability for the SE process. A common infrastructure is missing that provides an interoperable and distributed tool environment, addresses feature dependency selection, and automates toolchain workflow composition and execution. To address these challenges, this paper explores the practicality of a unifying Semantic Web Services approach towards Automated Software Engineering (SWS-ASE).buy now

SOA and the Enterprise -- Lessons from the City

Rajeev Mahajan — 12/20/2006 13:07

Enterprise wide rather than departmental focus differentiates SOA from the earlier legacy technologies like Client Server and Object Oriented Programming. This enterprise focus not only includes the IT personnel, but also the business personnel into the broader SOA ecosystem. This paper presents lessons learnt from three years of SOA implementation at a large City Government in the US from an enterprise wide application perspective.buy now

Runtime Integration of Reconfigurable Hardware in Service-Oriented Grids

M. Smith,B. Klose,R. Ewerth,T. Friese,M. Engel,B. Freisleben — 12/20/2006 13:10

In service-oriented Grid computing, great emphasis is placed on platform independence and cross-platform interoperability, at the price of a performance overhead incurred by the middleware and the high level programming languages typically utilized for developing software services. Reconfigurable hardware has been used in many areas of computing to improve the performance of applications by realizing performance critical parts in hardware. Typically, this is done in an application specific way, creating a custom solution for the project at hand for a specific reconfigurable hardware system. In this paper, we introduce a generic architecture in which Grid services can be dynamically transformed and run on reconfigurable hardware in a dynamic environment in which different types of reconfigurable hardware systems are present. Three approaches - static design time integration, dynamic run time integration and transparent dynamic run time integration - are presented for integrating such on-demand "hardware services" into a service-oriented Grid environment.buy now

A Transaction Model for Service Grid Environment and Implementation Considerations

Jinlei Jiang,Guangwen Yang,Meilin Shi — 12/20/2006 13:13

Transaction concept plays a key role in business success. However, existing transaction models are not applicable in service grid environment. Though many new models have been suggested, they still have some deficiencies, e.g., major extension to services are required, and they are hard to implement, to name a few. In this paper, a new model is proposed based on the analysis of existing work and the characteristics of service grid environment. Besides, model implementation issues are also covered.buy now

UsingWeb Services for Configuration and Deployment according to the CDDLM Standard

12/20/2006 13:14

As Web Services and Service Oriented Architectures are adopted, it is increasingly important to have standard and interoperable means to deploy and configure Web Services. Within the Global Grid Forum, HP, NEC, and Softricity have been developing a standard for Configuration Description, Deployment, and Lifecycle Management (CDDLM). In order to prove its feasibility, reference implementations are being developed. This paper describes an independent reference implementation of CDDLM and the experience in using Web Services for deployment in a standardized manner. Our main contributions are: the lessons learned in implementing this WS-based standard and an architecture for implementing CDDLM.buy now

Task Delegation in Active Web Intermediary Network

Chi-Hung Chi,Lin Liu,Xiaoyin Yu — 1/10/2007 22:33

In this paper, we formalize the concept of a delegation network for web intermediaries and present formal semantics for the responsibility of these actors. Key properties of the network are proven and method to judge an actor’s responsibility is given. This work is important because it determines the accuracy of task execution and the feasibility of content reuse in the network. buy now

Taming Web Services in the Wild

Daniel R. Kahan,Michael F. Nowlan,M. Brian Blake — 12/20/2006 13:17

Service-oriented computing (SOC) enables organizations and individual users to discover openlyaccessible capabilities realized as services over the Internet. Research in this area focuses on techniques for managing the messages that flow into and out of these services to ultimately compose higher-level functions. In our work, we investigate the nature of message definitions by analyzing real, fully-operational web services currently available on the Internet (i.e., from the wild). By leveraging insights into how real web service messages are defined, we develop enhanced syntactical methods to best aggregate these messages and ultimately the web services.buy now

A Framework for Intelligent Web Services: Combined HTN and CSP Approach

Incheon Paik,Daisuke Maruyama,Michael N. Huhns — 1/10/2007 22:42

Solving general real-life problems requires a set of appropriate services to be composed via planning, scheduled, and then executed. Web service composition is the most difficult aspect and is our focus. In this paper, we describe a new framework for intelligent semantic Web services that supports the planning and scheduling aspects by a combined HTN planner and CSP. The framework covers all of the procedures needed to deal with a user’s request, including domain analysis of the request, task flow decisions and CSP creation by the planner, and solving the CSP by a distributed CSP solver. buy now

Bridging Trust Relationships with Web Service Enhancements

Zhengping Wu,Alfred C. Weaver — 12/20/2006 15:08

With the development of web technology and distributed systems, online collaborations are becoming more common and more demanding. Web services now provide standard mechanisms to enable online interactions. Yet security, privacy and trust-related protection mechanisms for web services need additional development. In an interconnected network environment, physical connections with proper security protections are required for bridging two autonomous networks. Likewise, collaborating organizations need mechanisms for bridging extant relationships among cooperating parties that provide proper protection for privacy and trust. A trust establishment mechanism for web services must therefore ensure privacy and owner control at all times due to the subjectivity of trust relationships. This paper describes an indirect trust establishment mechanism to bridge and build new trust relationships from extant trust relationships providing privacy protection and owner control simultaneously. buy now

A Service-Oriented Trust Management Model on Application Server

Minghui ZHOU,Hong MEI — 1/10/2007 22:49

In the service-oriented architecture, the components deployed on application servers are published as web services. Though many researches focus on how to authorize at the web service level currently, there is little work involving the authorization gap between the service and its component implementation. This paper tries to bridge the gap by proposing a service-oriented trust management model, which expands the application server’s capability to deal with more complex trust relationship between service users and services, and supplies a flexible trust management mechanism to integrate authentication and authorization together. Moreover, the model provides a finer granularity access control, sustains delegation between users, and has a certain extent reasoning capability. The model has been implemented in a J2EE application server, and the experiment has demonstrated that the model has high flexibility and scalability. buy now

Adding OWL-S Support to the Existing UDDI Infrastructure

Jim Luo,Bruce Montrose,Anya Kim,Amitabh Khashnobish,Myong Kang — 12/20/2006 15:07

Although Universal, Description, Discovery and Integration (UDDI) is the de jure Web service registry standard, it is not suitable for handling semantic markups due to its flat data model and limited search capabilities. In this paper, we introduce an approach to support semantic service descriptions and queries using registries that conform to the UDDI Version 3 specification. Specifically, we present a scheme that allows users to store OWL-S service descriptions in the UDDI data model and use that information to perform semantic query processing. Our approach does not require any modification to the existing UDDI registries. The add-on modules only reside on the client-side machines that wish to take advantage of the semantic capabilities. This approach is completely backward compatible and can integrate seamlessly into the existing Service-Oriented Architecture (SOA) infrastructure. buy now

Behavioral matchmaking for service retrieval

Daniela Grigori,Juan Carlos Corrales,Mokrane Bouzeghoub — 12/20/2006 15:04

The capability to easily find useful services (software applications, software components, scientific computations) becomes increasingly critical in several fields. Current approaches for services retrieval are mostly limited to the matching of their inputs/outputs. Recent works have demonstrated that this approach is not sufficient to discover relevant components. In this paper we argue that, in many situations, the service discovery should be based on the specification of service behavior (in particular, the conversation protocol). The idea behind is to develop matching techniques that operate on behavior models and allow delivery of partial matches and evaluation of semantic distance between these matches and the user requirements. Consequently, even if a service satisfying exactly the user requirements does not exist, the most similar ones will be retrieved and proposed for reuse by extension or modification. To do so, we reduce the problem of behavioral matching to a graph matching problem and we adapt existing algorithms for this purpose. A prototype is presented (available as a web service) which takes as input two conversation protocols and evaluates the semantic distance between them; the prototype provides also the script of edit operations that can be used to alter the first model to render it identical with the second one. buy now

Transforming OWL-S Process Model into EDFA for Service Discovery

Lihui Lei,Zhenhua Duan — 12/20/2006 15:03

Current web services standards do not well support automatically discovering and selecting services that can be safely integrated with existing components. Semantic matching of service specifications based on the behaviors of web services, i.e., the ways a client may interact with the service, can be used to solve the problem. Therefore, the transformation of the OWL-S process model specifying the behaviors of web services into an extended deterministic finite state automaton (EDFA) is presented in this paper. The automata describe web services in a more accurate way: the nodes represent states maintained by services; the state transitions labelled by binary-tuples (input, output) rather than letters represent communication activities of services; moreover, the automaton structures describe the temporal sequences of communication activities that represents the behaviors of web services.The compatibility of web services can be evaluated with testing the emptiness of the languages accepted by EDFAs. buy now

Automated Syntactic Medation forWeb Service Integration

Martin Szomszor,Terry R. Payne,Luc Moreau — 12/20/2006 15:01

As the Web Services and Grid community adopt Semantic Web technology, we observe a shift towards higherlevel workflow composition and service discovery practices. While this provides excellent functionality to non-expert users, more sophisticated middleware is required to hide the details of service invocation and service integration. An investigation of a common Bioinformatics use case reveals that the execution of high-level workflow designs requires additional processing to harmonise syntactically incompatible service interfaces. In this paper, we present an architecture to support the automatic reconciliation of data formats in such Web Service worklflows. The mediation of data is driven by ontologies that encapsulate the information contained in heterogeneous data structures supplying a common, conceptual data representation. Data conversion is carried out by a Configurable Mediator component, consuming mappings between XML schemas and OWL ontologies. We describe our system and give examples of our mapping language against the background of a Bioinformatics use case. buy now

Strategic Web-Service Agreements

Sudarshan S. Chawathe — 1/10/2007 23:02

This paper addresses issues of strategy in Webservice composition, and inter-site collaboration in general. The results are useful for both human and artificial agents of a site who are responsible for determining Web-service agreements that are most profitable for that site. We discuss three specific questions in this area. (1) How should the profit resulting from a composition of Web-services be divided among the participants? (2) How can we counter the risk of serviceproviders misrepresenting their services in an attempt to gain a larger share of the profit? (3) Are stable configurations guaranteed or feasible when each service-provider’s decisions on how to collaborate (permit compositions) are guided solely by the goal of maximizing its profit? buy now

Keynote Speaker 1: Web Services at Amazon.com

12/15/2006 14:28

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.82

Keynote Speaker 2: Business Drivers for Services Computing

12/15/2006 14:30

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.83

Keynote Speaker 3: Service Computing: The AppExchange Platform

12/15/2006 14:31

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.84

Panel Session 1: Software and Services: Where Do They Meet?

12/15/2006 14:33

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.98

Tutorial 2: SOA Services and Solutions

12/15/2006 14:37

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.137

Tutorial 3: Automatic Web Service Composition

12/15/2006 14:39

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.138

Tutorial 4: Web Services on Rails: Using Ruby and Rails for Web Services Development and Mashups

12/15/2006 14:40

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.139

Tutorial 5: Business Agility and Process Management

12/15/2006 14:40

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.140

Tutorial 6: Security in SOA and Web Services

12/15/2006 14:41

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.141

Modelling and Solving QoS Composition Problem Using Fuzzy DisCSP

Xuan Thang Nguyen,Ryszard Kowalczyk,Manh Tan Phan — 12/20/2006 14:33

Web service compositions have attracted considerable efforts in the context of supporting enterprise application integrations. For a composite service, in addition to its functional requirements, QoS requirements are important and deserve a special attention. The central question to a QoS composition problem is how to compose a service from different subcomponent services so that its overall QoS can satisfy certain requirements. In this paper, we propose an agent-based method using Fuzzy Distributed Constraint Satisfaction Problem (Fuzzy DisCSP) techniques to solve this problem. We show that by using the composition structures, local constraints can be constructed and used with DisCSP. We also present an a new algorithm called the Fuzzy constraint satisfaction Algorithm for Distributed Environment (FADE) to solve the problem and discuss our experiment in building a prototypical system to prove the feasibility of our approach. buy now

Discovering and Improving Recovery Mechanisms of CompositeWeb Services

Sami Bhiri,Walid Gaaloul,Claude Godart — 12/20/2006 14:57

One of the main challenges that encounter Web services is how to ensure reliable compositions. In this paper we present an approach that starts from a composite service effective executions to improve its reliability. Basically, we propose a set of mining techniques to discover its model and its transactional behavior from an event based log. Then, based on this mining step, we use a set of rules to improve its recovery mechanisms. buy now

IntegratingWeb Services and Messaging

Ignacio Silva-Lepe,Michael J. Ward,Francisco Curbera — 12/20/2006 14:59

Web Services and Messaging, as application-toapplication communication paradigms, have so far been considered separately, with independent programming models and supporting middleware. Different efforts are now introducing messaging notions such as asynchrony, greater consumer cardinality, and looser coupling between web services. This trend will likely result in an extension of the web services programming model. It is not clear, however, that this extension will adhere to a pre-planned approach. A coherent approach requires a thorough integration of the web services and messaging paradigms. This paper proposes one such approach which, in addition to supporting the current style of web services interactions, allows the incorporation of messaging-style interactions under a common programming model. These messaging-style interactions include asynchronous request-response, oneway multi-consumer interactions, and even multiple-choice point-to-point interactions, common in message queuing systems. This paper also elaborates on a model for oneway multi-consumer interactions that integrates the publish/ subscribe mode of messaging into the web services programming model. A primary motivation for our approach is to take advantage of key messaging features, while exerting as small an impact as possible on the web services programming model. buy now

Augmenting Web Services Composition with Transactional Requirements

Frederic Montagut,Refik Molva — 12/20/2006 14:57

Current Web services composition approaches do not take into account transactional requirements defined by designers. The transactional challenges raised by the composition of Web services are twofold: relaxed atomicity and dynamicity. In this paper, we propose a new process to automate the design of transactional composite Web services. Our solution enables the composition ofWeb services not only according to functional requirements but also to transactional ones defined using the Acceptable Termination States model. The resulting composite Web service is compliant with the consistency requirements expressed by designers and its execution can easily be coordinated using the coordination rules provided as an outcome of our approach. buy now

Static Verification of Control and Data inWeb Service Compositions

Raman Kazhamiakin,Marco Pistore — 12/20/2006 14:54

The data exchanged among the web services participating to a composition are clearly very relevant for a correct behavior of the composition. Nevertheless, most of the approaches existing in the literature for the static verification of web service compositions ignore data, or require very small ranges to be associated to the data types. In this paper, we propose an approach for the verification of web service compositions that takes into account the data flows among the component process. The approach exploits abstraction techniques for modeling those aspects of data that are relevant for the correctness of the composition and hiding the aspects that are irrelevant. We show that building the right abstraction corresponds to defining those assumptions on the data manipulations performed by the component services which are crucial for the correctness of the composition.buy now

Message from the Program Chairs

12/15/2006 14:10

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.90

Message from the Application Services and Industry Track Chair

12/15/2006 14:11

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.88

IEEE Computer Society Technical Committee on Services Computing

12/15/2006 14:14

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.71

Conference Officers

12/15/2006 14:17

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.47

External Reviewers

12/15/2006 14:25

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.64

Panel Session 2: Web Services - A View from the Top

12/15/2006 14:34

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.99

Panel Session 3: Event-Driven Architectures and Complex Event Processing

12/15/2006 14:35

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.100

Tutorial 1: SOA and Web Services

12/15/2006 14:36

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.136

Automatic Matchmaking of Web Services

Sudhir Agarwal,Rudi Studer — 12/20/2006 14:22

Web services help in achieving increased automation across organizational boundaries. In this paper, we present an approach for annotating WSDL documents with semantically rich descriptions. We also present an algorithm that considers such annotations in addition to just the types of input and output parameters. Our matchmaking algorithm not only returns match/no-match answers but in case of a match a set of conditions under which a web service offers the desired functionality. buy now

Flex-SwA: Flexible Exchange of Binary Data Based on SOAP Messages with Attachments

Steffen Heinzl,Markus Mathes,Thomas Friese,Matthew Smith,Bernd Freisleben, — 12/20/2006 14:17

SOAP is the standard protocol for message exchange in web service environments. As an XML-based protocol, SOAP is not suitable for the transmission of large amounts of binary data. This fact has been addressed by the SOAP Messages with Attachments specification, which regulates the transfer of a SOAP message together with an arbitrary number of binary attachments composed within a MIME multipart/related message. Although this leads to a reduction of transmission overhead, web service communication using SOAP Messages with Attachments still lacks communication and processing flexibility. In this paper, we present a novel and more flexible way of handling attachments in SOAP-based web service environments. In contrast to SOAP Messages with Attachments, our approach offers message forwarding without additional communication cost and demand-driven evaluation and transmission of binary data, thus providing the opportunity to save time by overlapping service execution and data transmission. Buy now

Lightweight Checkpointing for Faster SOAP Deserialization

Nayef Abu-Ghazaleh,Michael J. Lewis, — 12/20/2006 14:17

Differential Deserialization (DDS) is an optimization technique that exploits similarities between incoming SOAP messages to reduce deserialization time. DDS works by checkpointing the state of the SOAP deserializer at various points while deserializing a message, and using those checkpoints to avoid full deserialization of similar messages. DDS can improve performance in many cases, but its benefit is limited by the potentially significant memory and processing overhead associated with its checkpointing mechanism. Differential checkpointing (DCP) substantially reduces memory use, but still requires significant processing overhead. In this paper, we introduce lightweight checkpointing (LCP), a checkpointing approach that significantly reduces the cost of both DDS and DCP, in terms of both memory use and processing time. LCP statically determines locations in the incoming message where it would be most efficient to create checkpoints. LCP creates checkpoints much faster than both our original DDS checkpointing mechanism and our DCP approach. LCP also has significantly smaller memory requirements. For example, in some of our test cases, LCP requires only 10% of the memory that DCP requires, and only 3% of the memory that our original approach required. In terms of processing time, deserialization with LCP is approximately 50% to 60% faster than without differential deserialization, when approximately half the message is unchanged from the previous message. Buy now

Semantic-Driven Matchmaking of Web Services Using Case-Based Reasoning

Taha Osman,Dhavalkumar Thakker,David Al-Dabass, — 12/20/2006 14:18

With the rapid proliferation of Web services as the medium of choice to securely publish application services beyond the firewall, the importance of accurate, yet flexible matchmaking of similar services gains importance both for the human user and for dynamic composition engines . In this paper, we present a novel approach that utilizes the case based reasoning methodology for modelling dynamic Web service discovery and matchmaking. Our framework considers Web services execution experiences in the decision making process and is highly adaptable to the service requester constraints. The framework also utilises OWL semantic descriptions extensively for implementing both the components of the CBR engine and the matchmaking profile of the Web services. Buy now

Heuristics for QoS-aware Web Service Composition

Rainer Berbner,Michael Spahn,Nicolas Repp,Oliver Heckmann,Ralf Steinmetz — 12/20/2006 14:53

This paper discusses the Quality of Service (QoS)- aware composition of Web Services. The work is based on the assumption that for each task in a workflow a set of alternative Web Services with similar functionality is available and that these Web Services have different QoS parameters and costs. This leads to the general optimization problem of how to select Web Services for each task so that the overall QoS and cost requirements of the composition are satisfied. Current proposals use exact algorithms or complex heuristics (e.g. genetic algorithms) to solve this problem. An actual implementation of a workflow engine (like our WSQoSX architecture), however, has to be able to solve these optimization problems in real-time and under heavy load. Therefore, we present a heuristic that performs extremely well while providing excellent (almost optimal) solutions. Using simulations, we show that in most cases our heuristic is able to calculate solutions that come as close as 99% to the optimal solution while taking less than 2% of the time of a standard exact algorithm. Further, we also investigate how much and under which circumstances the solution obtained by our heuristic can be further improved by other heuristics.buy now

Extensible Web Services Architecture for Notification in Large-Scale Systems

Krzysztof Ostrowski,Ken Birman — 12/20/2006 15:42

Existing web services notification and eventing standards are useful in many applications, but they have serious limitations precluding large-scale deployments: it is impossible to use IP multicast or for recipients to forward messages to others and scalable notification trees must be setup manually. We propose1 a design free of such limitations that could serve as a basis for extending or complementing these standards. The approach emerges from our prior work on QSM [1], a new web services eventing platform that can scale to extremely large environments. buy now

A Service-oriented Middleware for Runtime Web Services Interoperability (

Eric Wohlstadter,Stefan Tai,Thomas Mikalsen,Judah Diament,Isabelle Rouvellou — 12/20/2006 15:42

A major goal of service-oriented architectures is to enable software interoperability in heterogeneous and dynamic environments. Web services standards and protocols aim to support this goal and middleware systems implementing these standards and protocols consequently are needed. Maintenance and administration of middleware is made difficult due to variations in standards and their constant evolution. In this paper, we introduce a new service-oriented middleware architecture for runtime Web services interoperability. Different from other middleware systems our approach applies service-oriented computing principles on the middleware layer, thereby establishing an on-demand model for middleware features. Clients can use middleware as services, dynamically discovering and using the services as interoperability requirements are determined. Further, middleware as services allows middleware to be provided and managed separately from its clients. We present the policy-based programming model, architecture, and details of our middleware, and discuss new challenges that arise in this context, such as distribution of middleware services. The approach is validated through a scenario integrating web service transaction middleware. buy now

A Mixed Initiative Approach to Semantic Web Service Discovery and Composition: SAPa??s Guided Procedures Framework

Jinghai Rao,Dimitar Dimitrov,Paul Hofmann,Norman Sadeh — 1/10/2007 23:10

A central element of emerging Service Oriented Architectures (SOA) is the ability to develop new applications by composing enterprise functionality encapsulated in the form of services – whether within a given organization or across multiple ones. Semantic service annotations, including annotations of both functional and non-functional attributes, offer the prospect of facilitating this process and of producing higher quality solutions. A significant body of work in this area has aimed to fully automate this process, while assuming that all services already have rich and accurate annotations, In this article, we argue that this assumption is often unrealistic. Instead, we describe a mixed initiative framework for semantic web service discovery and composition that aims at flexibly interleaving human decision making and automated functionality in environments where annotations may be incomplete and even inconsistent. An initial version of this framework has been implemented in SAP’s Guided Procedures, a key element of SAP’s Enterperise Service Architecture (ESA). buy now

A Lightweight Software Design Process for Web Services Workflows

M. Brian Blake — 1/11/2007 00:16

Service-oriented computing (SOC) suggests that many open, network-accessible services will be available over the Internet for organizations to incorporate into their own processes. Developing new software systems by composing an organization’s local services and externally-available web services is conceptually different from system development supported by traditional software engineering lifecycles. Consumer organizations typically have no control over the quality and/or consistency of the external services that they incorporate, thus top-down software development lifecycles are impractical. Software architects and designers will require agile, lightweight processes to evaluate tradeoffs in system design based on the "estimated" responsiveness of external services coupled with known performance of local services. We introduce a model-driven software engineering approach for designing systems (i.e. workflows of web services) under these circumstances and a corresponding simulation-based evaluation tool. buy now

Web Services versus Distributed Objects: A Case Study of Performance and Interface Design

William R. Cook,Janel Barfield — 12/20/2006 15:47

Web services are promoted as a new model for distributed systems, yet many skeptics see them as simply a poor implementation of traditional remote procedure calls (RPC) or distributed objects. Previous comparisons support the skeptics: web services are shown to be significantly slower than RPC, and they lack features like automatic proxies. However, these studies are biased because they are based on an RPC communication style. Web services support a document-oriented style of communication that performs well even in the face of the high latency found in internet or business transactions. We investigate these issues by comparing the design and implementation of a small file server application implemented using RMI and web services. For this application, using the most straightforward implementation in both technologies, web services outperform RMI when accessing multiple/deeply nested files, especially over highlatency channels. However, the default web services interfaces are awkward to use, so we develop a technique for wrapping the web service to make it as easy to use as the distributed object implementation. The same wrappers are then used to implement the document-oriented communication style in RMI, which improves performance but significantly complicates the design. This case study provides a more detailed comparison of the relationship between web services and distributed objects. buy now

A Framework for Collecting Provenance in Data-Centric Scientific Workflows

Yogesh L. Simmhan,Beth Plale,Dennis Gannon — 12/20/2006 15:48

The increasing ability for the earth sciences to sense the world around us is resulting in a growing need for datadriven applications that are under the control of data-centric workflows composed of grid- and web- services. The focus of our work is on provenance collection for these workflows, necessary to validate the workflow and to determine quality of generated data products. The challenge we address is to record uniform and usable provenance metadata that meets the domain needs while minimizing the modification burden on the service authors and the performance overhead on the workflow engine and the services. The framework, based on a loosely-coupled publish-subscribe architecture for propagating provenance activities, satisfies the needs of detailed provenance collection while a performance evaluation of a prototype finds a minimal performance overhead (in the range of 1% for an eight service workflow using 271 data products). buy now

Evaluation and Modeling of Web Services Performance

Shiping Chen,Bo Yan,John Zic,Ren Liu,Alex Ng — 12/20/2006 15:50

While web services have been widely accepted as a platform-independent services-oriented technology, its performance remains a concern due to the verbosity and inefficiency inherent from using text-based XML. This paper presents a study of web services performance by evaluating the current implementations of web services and comparing them with a number of alternative technologies. This study gives a picture of the current web services performance behaviors and develops a simple performance model that can be used to estimate web services latencies. buy now

BizCast: Business Process Performance Model with Workload Overlap Analysis

Seiichi Koizumi,Shigeru Hosono,Satoru Fujita — 1/11/2007 01:38

In today's fast and ever changing business environments, it is very important to quickly adapt business processes to new business requirements, and to optimize their performance. From this viewpoint, business process performance prediction plays a key role in directing the business. Previous studies have shown that a network queuing model is able to predict the business process performance. In order to do this, the model requires details of the service’s inside behavior. This paper presents a business process performance model called ‘BizCast’, which enables us to estimate business process execution time under any given condition and not to require details of the service’s inside behavior. We especially focus on the overlap between business process instances to predict the performance based on the outside behavior. Prototype evaluation of the service model for supply chain services shows high accuracy, which is, at least, almost 0.9 correlation coefficient. buy now

Modelling End-to-end Quality-of-Service for Transaction-Based Services in Multi-Domain Environments

R.D. van der Mei,H.B. Meeuwissen — 12/20/2006 15:53

Next-generation service offerings will integrate information from multiple interconnected servers. For the commercial success of these services, the ability to deliver good end-to-end Quality-of-Service (QoS) is crucial. Today, no mature solutions exist for the problem of realizing high and guaranteed end-to-end QoS for transaction-based services in multi-domain environments. Service Level Agreements (SLAs) are a well-recognized concept to obtain QoS guarantees, but currently no satisfactory solutions exist for SPs to determine the set of combinations of per-domain SLAs that they need to negotiate with the other domain owners to deliver the desired end-to-end QoS. To this end, in this paper we introduce the new concept called SLA negotiation space, i.e. the set of combinations of per-domain SLAs that SPs need to negotiate with other domain owners to realize desired end-to-end QoS levels. In addition, to identify the SLA negotiation space, we propose a modelling framework to quantify the complex relation between the per-domain SLA parameters and the end-to-end QoS. The practical usefulness of our results is demonstrated by a realistic example.buy now

Proactive Service Discovery and Execution Using Agents

M. Brian Blake,David H. Fado,Gregory A. Mack — 12/20/2006 16:06

Service-oriented computing (SOC) suggests that the Internet will be an open repository of many modular capabilities realized as web services. Organizations may be able to leverage this SOC paradigm if their employees are able to ubiquitously incorporate such capabilities and their resulting information into their daily practices. It is impractical to assume that human users will be able to search vast distributed repositories at real-time. In addition, automated search tools may invasively present too much information. This paper presents an architecture, Software Agent-Based Groupware using Eservices (SAGE), that incorporates the use of intelligent agents to integrate human users with web services. SAGE provides background search and discovery approaches thus enabling human users to exploit service-based capabilities that were previously too time-consuming to locate and integrate. We present a multi-agent system where each agent learns the rule-based preferences of a human user and manages the incorporation of web services. buy now

Trust-based Resource Allocation in Web Services

Kaiqi Xiong,Harry Perros — 12/20/2006 16:16

With the number of e-Business applications dramatically increasing, service level agreement (SLA) will play an important part in Web services. A SLA is a combination of several quality of services (QoS), such as security, performance, and availability, agreed between a customer and a service provider. Most existing research addresses only one QoS metric, and in the case of the response time, the average time to process and complete a job is typically used. In this paper, we study trustworthiness, percentile response time and availability. We consider all these qualities for a trust-based resource allocation problem which typically arises in Web services applications. We formulate the trust-based resource allocation problem as an optimization problem under SLA constraints, and we solve it using an efficient numerical procedure.buy now

Author Index

12/20/2006 16:57

Full Article Text: DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/ICWS.2006.33