D. Millard, H. Davis, Y. Howard, L. Gilbert, R. Walters, Noura Abbas, G. Wills
Service-Oriented Architectures (SOAs) are increasingly deployed to achieve distributed systems that are modular, flexible and extensible. Designing for a SOA can be difficult, however. There are issues involving the granularity of the cooperating services, and there are no currently accepted conventions for describing a service or its interactions at an abstract level. This paper presents the Service Responsibility and Interaction Design Method (SRI-DM), an agile approach for engineering a Web Service design, based on capturing a scenario as a use-case, factoring this into a set of Service Responsibility and Collaboration Cards, and constructing a Sequence diagram illustrating their interactions in fulfilling the scenario. The paper presents the notation for each step and describes with the aid of an example how this process is used to create a service design within the domain of e-assessment.
{"title":"The Service Responsibility and Interaction Design Method: Using an Agile Approach for Web Service Design","authors":"D. Millard, H. Davis, Y. Howard, L. Gilbert, R. Walters, Noura Abbas, G. Wills","doi":"10.1109/ECOWS.2007.25","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.25","url":null,"abstract":"Service-Oriented Architectures (SOAs) are increasingly deployed to achieve distributed systems that are modular, flexible and extensible. Designing for a SOA can be difficult, however. There are issues involving the granularity of the cooperating services, and there are no currently accepted conventions for describing a service or its interactions at an abstract level. This paper presents the Service Responsibility and Interaction Design Method (SRI-DM), an agile approach for engineering a Web Service design, based on capturing a scenario as a use-case, factoring this into a set of Service Responsibility and Collaboration Cards, and constructing a Sequence diagram illustrating their interactions in fulfilling the scenario. The paper presents the notation for each step and describes with the aid of an example how this process is used to create a service design within the domain of e-assessment.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127336050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is concerned with the adaptive execution of workflows on resources consisting of a pool of machines and a pool of alternative web services. The hierarchical nature of workflows enables adaptation at multiple levels. In this work, adaptivity is concerned with changing the mapping of services to machines and workflow invocations to services, in order to meet the requirements of both user and provider. Specifically, a third-party workflow engine (ActiveBPEL) has been wrapped to supportmapping at these two levels. Results of experiments using the prototype within a cluster environment are presented which demon- strate a benefit from adapting in response to changes of user load and to changes in the pool of alternative services available during a workload. The experiments include a range of adaptivity scenarios and show that, by selection of an appropriate policy, a significant gain can be made.
{"title":"Experiments Towards Adaptation of Concurrent Workflows","authors":"Jim Smith, P. Watson","doi":"10.1109/ECOWS.2007.23","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.23","url":null,"abstract":"This paper is concerned with the adaptive execution of workflows on resources consisting of a pool of machines and a pool of alternative web services. The hierarchical nature of workflows enables adaptation at multiple levels. In this work, adaptivity is concerned with changing the mapping of services to machines and workflow invocations to services, in order to meet the requirements of both user and provider. Specifically, a third-party workflow engine (ActiveBPEL) has been wrapped to supportmapping at these two levels. Results of experiments using the prototype within a cluster environment are presented which demon- strate a benefit from adapting in response to changes of user load and to changes in the pool of alternative services available during a workload. The experiments include a range of adaptivity scenarios and show that, by selection of an appropriate policy, a significant gain can be made.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130222236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Web service discovery requires matching techniques for comparing and selecting web service descriptions based on user constraints. Semantic-based approaches achieve higher recall than other approaches (such as syntax-based approaches), because they employ ontological reasoning mechanisms to match syntactically heterogeneous descriptions. However, existing semantic-based approaches are not scalable as they perform an exhaustive search to locate composite services that conform to global constraints. This paper proposes a semantic-based matching technique that locates composite services. It relates attributes of services to a common attribute to ensure that they have the same scope. This enables the assigned values to be compared and evaluated against a given global constraint. Conforming composite services are located in polynomial time with a three-dimensional data structure that indexes services based on their types, attributes and the assigned values. Simulation results indicate that the proposed approach achieves higher recall than syntax-based approaches and is more scalable than existing semantic-based approaches.
{"title":"Matching Strictly Dependent Global Constraints for Composite Web Services","authors":"N. Gooneratne, Zahir Tari, James Harland","doi":"10.1109/ECOWS.2007.7","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.7","url":null,"abstract":"Web service discovery requires matching techniques for comparing and selecting web service descriptions based on user constraints. Semantic-based approaches achieve higher recall than other approaches (such as syntax-based approaches), because they employ ontological reasoning mechanisms to match syntactically heterogeneous descriptions. However, existing semantic-based approaches are not scalable as they perform an exhaustive search to locate composite services that conform to global constraints. This paper proposes a semantic-based matching technique that locates composite services. It relates attributes of services to a common attribute to ensure that they have the same scope. This enables the assigned values to be compared and evaluated against a given global constraint. Conforming composite services are located in polynomial time with a three-dimensional data structure that indexes services based on their types, attributes and the assigned values. Simulation results indicate that the proposed approach achieves higher recall than syntax-based approaches and is more scalable than existing semantic-based approaches.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132195944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the ubiquitous era, for Web services to become a universal communication paradigm, mobile devices enabled with Web services should be considered as an equal participant of the service-oriented architecture. Here, mobile devices play the role of clients, providers, or even brokers. To establish a distributed application framework on a P2P network environment, this paper presents a light-weight framework for hosting Web services on mobile devices. The proposed framework contains several built-in functionalities such as the processing of SOAP messages, the execution and migration of services, the management of context and service directory, and the publishing and discovery of services. To evaluate the performance of the proposed mobile Web service framework, a real-world scenario has been tested on physical devices connected by Bluetooth.
{"title":"A Light-weight Framework for Hosting Web Services on Mobile Devices","authors":"Yeon-Seok Kim, Kyong-Ho Lee","doi":"10.1109/ECOWS.2007.4","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.4","url":null,"abstract":"In the ubiquitous era, for Web services to become a universal communication paradigm, mobile devices enabled with Web services should be considered as an equal participant of the service-oriented architecture. Here, mobile devices play the role of clients, providers, or even brokers. To establish a distributed application framework on a P2P network environment, this paper presents a light-weight framework for hosting Web services on mobile devices. The proposed framework contains several built-in functionalities such as the processing of SOAP messages, the execution and migration of services, the management of context and service directory, and the publishing and discovery of services. To evaluate the performance of the proposed mobile Web service framework, a real-world scenario has been tested on physical devices connected by Bluetooth.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132310371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MASC (Manageable and Adaptive Service Compositions)1* is a policy-based middleware for monitoring and control of composite Web services execution. The monitorable requirements are specified in the WS-Policy4MASC language that extends WS-Policy by defining new types of monitoring and control policy assertions. This paper focuses on MASC monitoring capabilities to detect business exceptions and runtime faults. Our solutions are complementary to the existing approaches and provide: synchronous and asynchronous monitoring both at the SOAP messaging layer and the process orchestration layer, greater diversity of monitoring and control constructs, as well as the externalization of monitoring and adaptation actions from definitions of business processes. We implemented a MASC proof-of-concept prototype and evaluated it on monitoring and adaptation scenarios from a stock trading case study. Our performance studies indicate that MASC overhead and scalability are acceptable.
{"title":"WS-Policy based Monitoring of Composite Web Services","authors":"A. Erradi, P. Maheshwari, V. Tosic","doi":"10.1109/ECOWS.2007.31","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.31","url":null,"abstract":"MASC (Manageable and Adaptive Service Compositions)1* is a policy-based middleware for monitoring and control of composite Web services execution. The monitorable requirements are specified in the WS-Policy4MASC language that extends WS-Policy by defining new types of monitoring and control policy assertions. This paper focuses on MASC monitoring capabilities to detect business exceptions and runtime faults. Our solutions are complementary to the existing approaches and provide: synchronous and asynchronous monitoring both at the SOAP messaging layer and the process orchestration layer, greater diversity of monitoring and control constructs, as well as the externalization of monitoring and adaptation actions from definitions of business processes. We implemented a MASC proof-of-concept prototype and evaluated it on monitoring and adaptation scenarios from a stock trading case study. Our performance studies indicate that MASC overhead and scalability are acceptable.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114370955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cryptographically signed email has been widely used to provide the end-to-end authentication, integrity and non-repudiation. PGP mail and S/MIME have the significant drawback that the headers are unauthentic. DKIM protects specified headers, however, only between the sending server and the receiver. These lead to possible impersonation attacks and profiling of the email communication, and encourage spam and phishing activities. Furthermore, none of the currently available security mechanisms supports signature generation over partial email content by distinct signers, which might be useful in commercial scenarios. In order to handle these problems we suggest a new approach which can be considered as an advanced email security mechanism based on the popular XML technology. Our approach supersedes currently available email security standards in the sense of the higher flexibility and security, and can be transported via Web Services easily.
{"title":"Secure Emails in XML Format Using Web Services","authors":"L. Liao, Jörg Schwenk","doi":"10.1109/ECOWS.2007.12","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.12","url":null,"abstract":"Cryptographically signed email has been widely used to provide the end-to-end authentication, integrity and non-repudiation. PGP mail and S/MIME have the significant drawback that the headers are unauthentic. DKIM protects specified headers, however, only between the sending server and the receiver. These lead to possible impersonation attacks and profiling of the email communication, and encourage spam and phishing activities. Furthermore, none of the currently available security mechanisms supports signature generation over partial email content by distinct signers, which might be useful in commercial scenarios. In order to handle these problems we suggest a new approach which can be considered as an advanced email security mechanism based on the popular XML technology. Our approach supersedes currently available email security standards in the sense of the higher flexibility and security, and can be transported via Web Services easily.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117313336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The process of repairing Web Service failures may be connected to the nature of the fault that caused the error generating the failure. The selection strategy for composed services repair may be drawn from an analysis on temporal behavior of the fault, assessing if fault is transient, intermittent or permanent. The repair process strictly depends on the permanence type of faults, as substitution is applied with permanent faults, while retry is chosen with transient faults and the retry period is to be determined. In this paper we propose a methodology and a tool for learning the repair strategies of Web Services to automatically select repair actions. This methodology is able to incrementally learn its knowledge of repairs, as faults are repaired. Thus, it is at runtime possible to achieve adaptability according to the current fault features and to the history of the previously performed repair actions. This learning technique and the strategy selection are based on a Bayesian classification of faults in permanent, intermittent and transient, followed by a comparative analysis between current fault features and previously classified faults features which suggests which repair strategy has to be applied. Therefore, this methodology includes the ability to learn autonomously both model parameters, which are useful to determine the fault type, and repair strategies which are successful and proper for a particular fault.
{"title":"Automatic Learning of Repair Strategies for Web Services","authors":"B. Pernici, A. Rosati","doi":"10.1109/ECOWS.2007.13","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.13","url":null,"abstract":"The process of repairing Web Service failures may be connected to the nature of the fault that caused the error generating the failure. The selection strategy for composed services repair may be drawn from an analysis on temporal behavior of the fault, assessing if fault is transient, intermittent or permanent. The repair process strictly depends on the permanence type of faults, as substitution is applied with permanent faults, while retry is chosen with transient faults and the retry period is to be determined. In this paper we propose a methodology and a tool for learning the repair strategies of Web Services to automatically select repair actions. This methodology is able to incrementally learn its knowledge of repairs, as faults are repaired. Thus, it is at runtime possible to achieve adaptability according to the current fault features and to the history of the previously performed repair actions. This learning technique and the strategy selection are based on a Bayesian classification of faults in permanent, intermittent and transient, followed by a comparative analysis between current fault features and previously classified faults features which suggests which repair strategy has to be applied. Therefore, this methodology includes the ability to learn autonomously both model parameters, which are useful to determine the fault type, and repair strategies which are successful and proper for a particular fault.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130006123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arun Mukhija, A. Dingwall-Smith, David S. Rosenblum
A major advantage offered by Web services technologies is the ability to dynamically discover and invoke services. This ability is particularly important for operations of many applications executing in open dynamic environments. The QoS properties of the required and provided services play a significant role in dynamic discovery and invocation of services in open dynamic environments. In this paper, we discuss our approach to QoS specification and service provider selection, in the context of our work on the Dino project. The service provider selection algorithm used in Dino takes into account the relative benefit offered by a provider with respect to the requester-specified QoS criteria, and the trustworthiness of the provider. We explain our approach using an example from the automotive domain.
{"title":"QoS-Aware Service Composition in Dino","authors":"Arun Mukhija, A. Dingwall-Smith, David S. Rosenblum","doi":"10.1109/ECOWS.2007.24","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.24","url":null,"abstract":"A major advantage offered by Web services technologies is the ability to dynamically discover and invoke services. This ability is particularly important for operations of many applications executing in open dynamic environments. The QoS properties of the required and provided services play a significant role in dynamic discovery and invocation of services in open dynamic environments. In this paper, we discuss our approach to QoS specification and service provider selection, in the context of our work on the Dino project. The service provider selection algorithm used in Dino takes into account the relative benefit offered by a provider with respect to the requester-specified QoS criteria, and the trustworthiness of the provider. We explain our approach using an example from the automotive domain.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133227269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Web services are often employed to create wide distributed evolvable applications from existing components that constitute a service-based software system. Services-Oriented Architectures promote loose coupling, services distribution, dynamicity and agility and introduce new engineering issues. As services involved in a SOA are remote and autonomous services, the SOA designer does not control them and unpredictable behaviour can occur. Services orchestration is a key issue in order to fit expectations and reach objectives. Thus, Service-Oriented Architectures have to be designed, analized and deployed with rigor in order to be plainly useful and quality aware. Orchestration languages (BPEL4WS, BPML, etc.) fail in some points due to the lack of formalization and expressiveness, particularly when addressing service-based architecture maintenance and evolution. This paper presents Diapason, a formal framework that allows us to formally support SOA design, ckecking, execution and evolution.
{"title":"A Formal Framework For Building, Checking And Evolving Service Oriented Architectures","authors":"H. Verjus, Frédéric Pourraz","doi":"10.1109/ECOWS.2007.18","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.18","url":null,"abstract":"Web services are often employed to create wide distributed evolvable applications from existing components that constitute a service-based software system. Services-Oriented Architectures promote loose coupling, services distribution, dynamicity and agility and introduce new engineering issues. As services involved in a SOA are remote and autonomous services, the SOA designer does not control them and unpredictable behaviour can occur. Services orchestration is a key issue in order to fit expectations and reach objectives. Thus, Service-Oriented Architectures have to be designed, analized and deployed with rigor in order to be plainly useful and quality aware. Orchestration languages (BPEL4WS, BPML, etc.) fail in some points due to the lack of formalization and expressiveness, particularly when addressing service-based architecture maintenance and evolution. This paper presents Diapason, a formal framework that allows us to formally support SOA design, ckecking, execution and evolution.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125139714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For improved flexibility and concurrent usage existing transaction management models for Web services relax the isolation property of Web service-based transactions. Correctness of the concurrent execution then has to be ensured by commit order-preserving transaction schedulers. However, local schedulers of service providers typically do take into account neither time constraints for committing the whole transaction, nor the individual services' constraints when scheduling decisions are made. This often leads to an unnecessary blocking of transactions by (possibly long-running) others. In this paper, we propose a novel nonblocking scheduling mechanism that is used prior to the actual service invocations. Its aim is to reach an agreement between the client and all participating providers on what transaction processing times have to be expected, accepted, and guaranteed. This enables service consumers to find a set of best suited providers fitting their deadlines. Service providers on the other hand can benefit from the proposed mechanism due to the now possible intelligent scheduling of service invocations for best throughput. In fact, our experiments show a significant improvement in terms of overall throughput, service chain completions and resources' utilization.
{"title":"Nonblocking Scheduling for Web Service Transactions","authors":"N. Gooneratne, Z. Tari, James Harland","doi":"10.1109/ECOWS.2007.15","DOIUrl":"https://doi.org/10.1109/ECOWS.2007.15","url":null,"abstract":"For improved flexibility and concurrent usage existing transaction management models for Web services relax the isolation property of Web service-based transactions. Correctness of the concurrent execution then has to be ensured by commit order-preserving transaction schedulers. However, local schedulers of service providers typically do take into account neither time constraints for committing the whole transaction, nor the individual services' constraints when scheduling decisions are made. This often leads to an unnecessary blocking of transactions by (possibly long-running) others. In this paper, we propose a novel nonblocking scheduling mechanism that is used prior to the actual service invocations. Its aim is to reach an agreement between the client and all participating providers on what transaction processing times have to be expected, accepted, and guaranteed. This enables service consumers to find a set of best suited providers fitting their deadlines. Service providers on the other hand can benefit from the proposed mechanism due to the now possible intelligent scheduling of service invocations for best throughput. In fact, our experiments show a significant improvement in terms of overall throughput, service chain completions and resources' utilization.","PeriodicalId":436126,"journal":{"name":"Fifth European Conference on Web Services (ECOWS'07)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129619641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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