Sea ice in the western Antarctic Peninsula （WAP） region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice changes affec...Sea ice in the western Antarctic Peninsula （WAP） region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice changes affect ocean stratification and freshwater balance and in turn impact every component of the polar marine ecosystem. Long-term observations from the WAP nearshore and offshore regions show a pattern of chlorophyll （Chl） variability with three to five years of negative Chl anomalies interrupted by one or two years of positive anomalies （high and low Chl regimes）. Both field observations and results from an inverse food-web model show that these high and low Chl regimes differed significantly from each other, with high primary productivity and net community production （NCP） and other rates associated with the high Chl years and low rates with low Chl years. Gross primary production rates （GPP） averaged 30 mmolC.m^-2.d^-1 in the low Chl years and 100 mmolC.m-2.d1 in the high Chl years. Both large and small phytoplankton were more abundant and more productive in high Chl years than in low Chl years. Similarly, krill were more important as grazers in high Chl years, but did not differ from microzooplankton in high or low Chl years. Microzooplankton did not differ between high and low Chl years. Net community production differed significantly between high and low Chl years, but mobilized a similar proportion of GPP in both high and low Chl years. The composition of the NCP was uniform in high and low Chl years. These results emphasize the importance of microbial components in the WAP plankton system and suggest that food webs dominated by small phytoplankton can have pathways that funnel production into NCP, and likely, export.展开更多
As the increasing popularity and complexity of Web applications and the emergence of their new characteristics, the testing and maintenance of large, complex Web applications are becoming more complex and difficult. W...As the increasing popularity and complexity of Web applications and the emergence of their new characteristics, the testing and maintenance of large, complex Web applications are becoming more complex and difficult. Web applications generally contain lots of pages and are used by enormous users. Statistical testing is an effective way of ensuring their quality. Web usage can be accurately described by Markov chain which has been proved to be an ideal model for software statistical testing. The results of unit testing can be utilized in the latter stages, which is an important strategy for bottom-to-top integration testing, and the other improvement of extended Markov chain model (EMM) is to present the error type vector which is treated as a part of page node. this paper also proposes the algorithm for generating test cases of usage paths. Finally, optional usage reliability evaluation methods and an incremental usability regression testing model for testing and evaluation are presented. Key words statistical testing - evaluation for Web usability - extended Markov chain model (EMM) - Web log mining - reliability evaluation CLC number TP311. 5 Foundation item: Supported by the National Defence Research Project (No. 41315. 9. 2) and National Science and Technology Plan (2001BA102A04-02-03)Biography: MAO Cheng-ying (1978-), male, Ph.D. candidate, research direction: software testing. Research direction: advanced database system, software testing, component technology and data mining.展开更多
A formal model representing the navigation behavior of a Web application as the Kripke structure is proposed and an approach that applies model checking to test case generation is presented. The Object Relation Diagra...A formal model representing the navigation behavior of a Web application as the Kripke structure is proposed and an approach that applies model checking to test case generation is presented. The Object Relation Diagram as the object model is employed to describe the object structure of a Web application design and can be translated into the behavior model. A key problem of model checking-based test generation for a Web application is how to construct a set of trap properties that intend to cause the violations of model checking against the behavior model and output of counterexamples used to construct the test sequences. We give an algorithm that derives trap properties from the object model with respect to node and edge coverage criteria.展开更多
In this paper, a model based colored Petri net （CPN） to provide semantic support for web service composition is proposed, and the reliability and maintainability of composite services are improved. The composite con...In this paper, a model based colored Petri net （CPN） to provide semantic support for web service composition is proposed, and the reliability and maintainability of composite services are improved. The composite constructs in the model are sequence, concurrent, choice, loop and replace. The web service is formally defined by a CPN. A closed composing algebra is defined to obtain a framework which enables declarative composition of web services. Availability, confidentiality, and integrity of composite service are analyzed within the framework of the model based CPN.展开更多
Smart sustainable city is that uses the technology to transform their core systems and optimize the exploitation of limited resources;it is a knowledge-based system that provides real-time insights to stakeholders. As...Smart sustainable city is that uses the technology to transform their core systems and optimize the exploitation of limited resources;it is a knowledge-based system that provides real-time insights to stakeholders. As a result of the challenges facing the cities of the Gaza Strip regarding population growth, lack of resources, increased demand for materials, the siege imposed on the Gaza Strip for more than twelve years, the smart city approach can contribute to mitigating these challenges and creating opportunities and solutions for many of these problems. Thus, this study aims to promote sustainable urban development through the adoption of smart city approaches using the city’s 3D representation and analysis capabilities to reflect and define the current situation and formulate a future vision using GIS and Building Information Modeling (BIM) considering Sheikh Hamad city as a case study. This involves developing a GIS web-based 3D model of the urban landscape of the city and creating a geometric descriptive database that includes the various elements of the city such as buildings, services and other facilities. The constructed database is to be automatically updated and can be used to facilitate documentation, transparency and help in decision-making process. The 3D smart city can also benefit stakeholders, government officials, private sectors as well as the city citizens. Therefore, urban services will be more efficient, and the cities of the Gaza Strip will be able to achieve sustainable development and competition in difficult economic, environmental and social conditions. This study recommends the use of BIM and GIS technologies in the transformation to a smart city concept as well as the rehabilitation of existing cadres to enable them to use those technologies to achieve the goal of improving the quality of life and facilitating the daily lives of people.展开更多
Software engineering＇s lifecycle models havc proven to be very important for traditional software development. However, can these models be applied to the development of Web-based applications as well？ In recent yea...Software engineering＇s lifecycle models havc proven to be very important for traditional software development. However, can these models be applied to the development of Web-based applications as well？ In recent years, Web-based applications have become more and more complicated and a lot of efforts have been placed on introducing new technologies such as J2EE, PhP, and .NET, etc., which have been universally accepted as the development technologies for Web-based applications. However, there is no universally accepted process model for the development of Web-based applications. Moreover, shaping the process model for small medium-sized enterprises （SMEs）, which have limited resources, has been relatively neglected. Based on our previous work, this paper presents an expanded lifecycle process model for the development of Web-based applications in SMEs. It consists of three sets of processes, i.e., requirement processes, development processes, and evolution processes. Particularly, the post-delivery evolution processes are important to SMEs to develop and maintain quality web applications with limited resources and time.展开更多
Web-services are highly distributed programs, and concurrent software is notoriously error-prone. Model checking is a powerful technique to find bugs in concurrent systems. However, the existing model checkers have no...Web-services are highly distributed programs, and concurrent software is notoriously error-prone. Model checking is a powerful technique to find bugs in concurrent systems. However, the existing model checkers have no enough ability to support for the programming languages and communication mechanisms used for Web services. We propose to use Kripke structures as means of modeling Web service. This paper presents an automated way to extract formal models from programs implementing Web services using predicate abstraction for abstract model checking. The abstract models are checked by means of a model checker that implements automatic abstraction refinement. These results enable the verification of the applications that implement Web services.展开更多
The paper proposes a conference control model between a web server and a telecom application server,referred to as the Conference Directed Graph(CDG) ,and describes an asynchronous communication mechanism between them...The paper proposes a conference control model between a web server and a telecom application server,referred to as the Conference Directed Graph(CDG) ,and describes an asynchronous communication mechanism between them. The Corba Interface Definition Language(IDL) interfaces are defined,and a message sequence chart is illustrated. This web conference control model provides conference users with a new approach to manage and control a conference and the participants. The performance of the system prototype is analyzed and verified in the 863 project named "The Multi-media and Mobile Services Enabled Soft-switch System".展开更多
In recent years, web technology carried on growing and at same time, the number of internet users increased significantly in number. Today, a Web server is capable of processing millions of requests per day, but durin...In recent years, web technology carried on growing and at same time, the number of internet users increased significantly in number. Today, a Web server is capable of processing millions of requests per day, but during the peak period may collapse and becomes critical causing unavailability of the services offered by the servers. That is why Web server performance is a topic of great interest to many researchers. In this paper, we evaluate experimentally the impact of JSP and PHP dynamic content technology: JSP and PHP with access to a database of performance data of Apache Web server. Using the “ApacheBench” performance measurement tool, the approach is to compare the performances of four different configurations of a Web server, such as: Apache Web server implementing JSP technology with access to PostgreSQL database, Apache using PHP technology with the PostgreSQL as database, Apache Web server using the JSP technology with access to MySQL database, finally Apache and PHP with DBMS MySQL. At the end of this article, we also present a Simulink model of Web server performance based on the simple M/M/1 queue. During the modeling, the MATLAB software was used.展开更多
As the web-server based business is rapidly developed and popularized, how to evaluate and improve the reliability of web-servers has been extremely important. Although a large num- ber of software reliability growth ...As the web-server based business is rapidly developed and popularized, how to evaluate and improve the reliability of web-servers has been extremely important. Although a large num- ber of software reliability growth models （SRGMs）, including those combined with multiple change-points （CPs）, have been available, these conventional SRGMs cannot be directly applied to web soft- ware reliability analysis because of the complex web operational profile. To characterize the web operational profile precisely, it should be realized that the workload of a web server is normally non-homogeneous and often observed with the pattern of random impulsive shocks. A web software reliability model with random im- pulsive shocks and its statistical analysis method are developed. In the proposed model, the web server workload is characterized by a geometric Brownian motion process. Based on a real data set from IIS server logs of ICRMS website （www.icrms.cn）, the proposed model is demonstrated to be powerful for estimating impulsive shocks and web software reliability.展开更多
Web service （WS） is an emerging software technology, especially acting an important role in cloud computing. The WS choreography description language （WS-CDL） is the standard for modeling the observable behavior o...Web service （WS） is an emerging software technology, especially acting an important role in cloud computing. The WS choreography description language （WS-CDL） is the standard for modeling the observable behavior of WS composition across multiple participants from a global point of view. However, it lacks of a formal semantics and could easily lead to misunderstanding and different implementations. In this paper, the WS-CDL based specifications are formally extracted in a communicating sequential process supporting a formal approach to checking WS models. In addition, formalisms and model checking are explicitly illustrated through a simple but non-trivial example with the help of model checker process analysis toolkit （PAT）.展开更多
A novel semantic model of Web service descrip tion and discovery was proposed through an extension for profile model of Web ontology language for services （OWL-S） in this paper. Similarity matching of Web services w...A novel semantic model of Web service descrip tion and discovery was proposed through an extension for profile model of Web ontology language for services （OWL-S） in this paper. Similarity matching of Web services was implemented through computing weighted summation of semantic similarity value based on specific domain ontology and dynamical satisfy extent evaluation for quality of service （QoS）. Experiments show that the provided semantic matching model is efficient.展开更多
Model checking techniques have been widely used in verifying web service compositions to ensure the trustworthi- ness. However, little research has focused on testing web services. Based on the research of model check...Model checking techniques have been widely used in verifying web service compositions to ensure the trustworthi- ness. However, little research has focused on testing web services. Based on the research of model checking techniques~ we propose a model checking based approach for testing web service composition which is described by using the web services choreography description language （WS-CDL）. According to worldwide web consortium （W3C） candidate recommendation, the WS-CDL specification provides a language for characterizing interactions between distinct web services using XML. Since the behaviors of web service composition are asynchronous, distributed, low-coupled and platform independent, we employ the guarded automata （GA） model for specifying the composition described in WS-CDL and using the simple promela interpreter （SPIN） model checker for detecting the collaborations of web services. Test cases can be transformed from counterexamples generated by SPIN using adequacy criteria. In this paper we apply the transition coverage criterion for generating counterex- amples. To illustrate our approach, we set ＂E-commerce service system＂ as an example for demonstrating how test cases can be generated using SPIN for compositions specified in WS-CDL.展开更多
The usability of an interface is a fundamental issue to elucidate. Many researchers argued that many usability results and recommendations lack empirical and experimental data. In this research, the usability of the w...The usability of an interface is a fundamental issue to elucidate. Many researchers argued that many usability results and recommendations lack empirical and experimental data. In this research, the usability of the web pages is evaluated using several carefully selected statistical models. Universities web pages are chosen as subjects for this work for ease of comparison and ease of collecting data. A series of experiments has been conducted to investigate into the usability and design of the universities web pages. Prototype web pages have been developed according to the structured methodologies of web pages design and usability. Universities web pages were evaluated together with the prototype web pages using a questionnaire which was designed according to the Human Computer Interactions (HCI) heuristics. Nine (users) respondents’ variables and 14 web pages variables (items) were studied. Stringent statistical analysis was adopted to extract the required information to form the data acquired, and augmented interpretation of the statistical results was followed. The results showed that the analysis of variance (ANOVA) procedure showed there were significant differences among the universities web pages regarding most of the 23 items studied. Duncan Multiple Range Test (DMRT) showed that the prototype usability performed significantly better regarding most of the items. The correlation analysis showed significant positive and negative correlations between many items. The regression analysis revealed that the most significant factors (items) that contributed to the best model of the universities web pages design and usability were: multimedia in the web pages, the web pages icons (alone) organisation and design, and graphics attractiveness. The results showed some of the limitations of some heuristics used in conventional interface systems design and proposed some additional heuristics in web pages design and usability.展开更多
The emerging Model-Driven Engineering (MDE) paradigm advocates the use of models as first-class citizens in the software development process, while artifacts such as documentation and source-code can be quickly produc...The emerging Model-Driven Engineering (MDE) paradigm advocates the use of models as first-class citizens in the software development process, while artifacts such as documentation and source-code can be quickly produced from those models by using automated transformations. Even though many MDE-oriented approaches, languages and tools have been developed in the recent past, there is no standard that concretely defines a specific sequence of steps to obtain a functional software system from a model. Thus, the existing approaches present numerous differences among themselves, because each one handles the problems inherent to software development in its own way. This paper presents and discusses a reference model for the comparative study of current MDE approaches in the scope of web-application development. This reference model focuses on relevant aspects such as modeling language scope (domain, business-logic, user-interface), usage of patterns, separation of concerns, model transformations, tool support, and deployment details like web-platform independence and traditional programming required. The ultimate goal of this paper is to determine the aspects that will be of greater importance in future web-oriented MDE languages.展开更多
Model-Driven Engineering (MDE) by reframing software development as the transformation of high-level models, promises lots of gains to Software Engineering in terms of productivity, quality and reusability. Although a...Model-Driven Engineering (MDE) by reframing software development as the transformation of high-level models, promises lots of gains to Software Engineering in terms of productivity, quality and reusability. Although a number of empirical studies have established the reality of these gains, there are still lots of reluctances toward the adoption of MDE in practice. This resistance can be explained by several technological and social factors among which a natural scepticism toward novel approaches. In this paper we attempt to provide arguments to help alleviate this scepticism by conducting an assessment of a MDE approach. Our goal is to show that although this MDE is novel, it retains similarities with the conventional Software Engineering approach while automating aspects of it.展开更多
基金supported by NSF Polar Programs awards ANT-1344502 and PLR-1440435 to HWD at Lamont-Doherty Earth ObservatorySFS and SCD were supported partly by Woods Hole Oceanographic Institution
文摘Sea ice in the western Antarctic Peninsula （WAP） region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice changes affect ocean stratification and freshwater balance and in turn impact every component of the polar marine ecosystem. Long-term observations from the WAP nearshore and offshore regions show a pattern of chlorophyll （Chl） variability with three to five years of negative Chl anomalies interrupted by one or two years of positive anomalies （high and low Chl regimes）. Both field observations and results from an inverse food-web model show that these high and low Chl regimes differed significantly from each other, with high primary productivity and net community production （NCP） and other rates associated with the high Chl years and low rates with low Chl years. Gross primary production rates （GPP） averaged 30 mmolC.m^-2.d^-1 in the low Chl years and 100 mmolC.m-2.d1 in the high Chl years. Both large and small phytoplankton were more abundant and more productive in high Chl years than in low Chl years. Similarly, krill were more important as grazers in high Chl years, but did not differ from microzooplankton in high or low Chl years. Microzooplankton did not differ between high and low Chl years. Net community production differed significantly between high and low Chl years, but mobilized a similar proportion of GPP in both high and low Chl years. The composition of the NCP was uniform in high and low Chl years. These results emphasize the importance of microbial components in the WAP plankton system and suggest that food webs dominated by small phytoplankton can have pathways that funnel production into NCP, and likely, export.
文摘As the increasing popularity and complexity of Web applications and the emergence of their new characteristics, the testing and maintenance of large, complex Web applications are becoming more complex and difficult. Web applications generally contain lots of pages and are used by enormous users. Statistical testing is an effective way of ensuring their quality. Web usage can be accurately described by Markov chain which has been proved to be an ideal model for software statistical testing. The results of unit testing can be utilized in the latter stages, which is an important strategy for bottom-to-top integration testing, and the other improvement of extended Markov chain model (EMM) is to present the error type vector which is treated as a part of page node. this paper also proposes the algorithm for generating test cases of usage paths. Finally, optional usage reliability evaluation methods and an incremental usability regression testing model for testing and evaluation are presented. Key words statistical testing - evaluation for Web usability - extended Markov chain model (EMM) - Web log mining - reliability evaluation CLC number TP311. 5 Foundation item: Supported by the National Defence Research Project (No. 41315. 9. 2) and National Science and Technology Plan (2001BA102A04-02-03)Biography: MAO Cheng-ying (1978-), male, Ph.D. candidate, research direction: software testing. Research direction: advanced database system, software testing, component technology and data mining.
基金Supported by the National Natural Science Foundation of China (60673115)the National Basic Research Program of China (973 Program) (2002CB312001)the Open Foundation of State Key Laboratory of Soft-ware Engineering (SKLSE05-13)
文摘A formal model representing the navigation behavior of a Web application as the Kripke structure is proposed and an approach that applies model checking to test case generation is presented. The Object Relation Diagram as the object model is employed to describe the object structure of a Web application design and can be translated into the behavior model. A key problem of model checking-based test generation for a Web application is how to construct a set of trap properties that intend to cause the violations of model checking against the behavior model and output of counterexamples used to construct the test sequences. We give an algorithm that derives trap properties from the object model with respect to node and edge coverage criteria.
基金Project supported by the National Natural Science Foundation of China （Grant No.60403027）
文摘In this paper, a model based colored Petri net （CPN） to provide semantic support for web service composition is proposed, and the reliability and maintainability of composite services are improved. The composite constructs in the model are sequence, concurrent, choice, loop and replace. The web service is formally defined by a CPN. A closed composing algebra is defined to obtain a framework which enables declarative composition of web services. Availability, confidentiality, and integrity of composite service are analyzed within the framework of the model based CPN.
文摘Smart sustainable city is that uses the technology to transform their core systems and optimize the exploitation of limited resources;it is a knowledge-based system that provides real-time insights to stakeholders. As a result of the challenges facing the cities of the Gaza Strip regarding population growth, lack of resources, increased demand for materials, the siege imposed on the Gaza Strip for more than twelve years, the smart city approach can contribute to mitigating these challenges and creating opportunities and solutions for many of these problems. Thus, this study aims to promote sustainable urban development through the adoption of smart city approaches using the city’s 3D representation and analysis capabilities to reflect and define the current situation and formulate a future vision using GIS and Building Information Modeling (BIM) considering Sheikh Hamad city as a case study. This involves developing a GIS web-based 3D model of the urban landscape of the city and creating a geometric descriptive database that includes the various elements of the city such as buildings, services and other facilities. The constructed database is to be automatically updated and can be used to facilitate documentation, transparency and help in decision-making process. The 3D smart city can also benefit stakeholders, government officials, private sectors as well as the city citizens. Therefore, urban services will be more efficient, and the cities of the Gaza Strip will be able to achieve sustainable development and competition in difficult economic, environmental and social conditions. This study recommends the use of BIM and GIS technologies in the transformation to a smart city concept as well as the rehabilitation of existing cadres to enable them to use those technologies to achieve the goal of improving the quality of life and facilitating the daily lives of people.
文摘Software engineering＇s lifecycle models havc proven to be very important for traditional software development. However, can these models be applied to the development of Web-based applications as well？ In recent years, Web-based applications have become more and more complicated and a lot of efforts have been placed on introducing new technologies such as J2EE, PhP, and .NET, etc., which have been universally accepted as the development technologies for Web-based applications. However, there is no universally accepted process model for the development of Web-based applications. Moreover, shaping the process model for small medium-sized enterprises （SMEs）, which have limited resources, has been relatively neglected. Based on our previous work, this paper presents an expanded lifecycle process model for the development of Web-based applications in SMEs. It consists of three sets of processes, i.e., requirement processes, development processes, and evolution processes. Particularly, the post-delivery evolution processes are important to SMEs to develop and maintain quality web applications with limited resources and time.
基金the National Natural Science Foundation of China (60663005, 60563005)the Natural Science Foundation of Guangxi Province (0542036, 0728093, 0728089)
文摘Web-services are highly distributed programs, and concurrent software is notoriously error-prone. Model checking is a powerful technique to find bugs in concurrent systems. However, the existing model checkers have no enough ability to support for the programming languages and communication mechanisms used for Web services. We propose to use Kripke structures as means of modeling Web service. This paper presents an automated way to extract formal models from programs implementing Web services using predicate abstraction for abstract model checking. The abstract models are checked by means of a model checker that implements automatic abstraction refinement. These results enable the verification of the applications that implement Web services.
基金the National High-Tech Research and De-velopment Plan of China (No.2001AA121021)the Na-tional Research Foundation for the Doctoral Program of Higher Education of China (No.20020013004)+2 种基金the Na-tional Grand Fundamental Research 973 Program of China (No.2003CB314806)the National Natural Science Foundation for Distinguished Young Scholars of China (No.60125101)the Cheung Kong Scholar’s Program and the Promotion Project for Creative Teams of the Ministry of Education (Networking Theory and Tech-nology in Telecommunication) (No.IRT0410).
文摘The paper proposes a conference control model between a web server and a telecom application server,referred to as the Conference Directed Graph(CDG) ,and describes an asynchronous communication mechanism between them. The Corba Interface Definition Language(IDL) interfaces are defined,and a message sequence chart is illustrated. This web conference control model provides conference users with a new approach to manage and control a conference and the participants. The performance of the system prototype is analyzed and verified in the 863 project named "The Multi-media and Mobile Services Enabled Soft-switch System".
文摘In recent years, web technology carried on growing and at same time, the number of internet users increased significantly in number. Today, a Web server is capable of processing millions of requests per day, but during the peak period may collapse and becomes critical causing unavailability of the services offered by the servers. That is why Web server performance is a topic of great interest to many researchers. In this paper, we evaluate experimentally the impact of JSP and PHP dynamic content technology: JSP and PHP with access to a database of performance data of Apache Web server. Using the “ApacheBench” performance measurement tool, the approach is to compare the performances of four different configurations of a Web server, such as: Apache Web server implementing JSP technology with access to PostgreSQL database, Apache using PHP technology with the PostgreSQL as database, Apache Web server using the JSP technology with access to MySQL database, finally Apache and PHP with DBMS MySQL. At the end of this article, we also present a Simulink model of Web server performance based on the simple M/M/1 queue. During the modeling, the MATLAB software was used.
基金supported by the International Technology Cooperation Project of Guizhou Province(QianKeHeWaiGZi[2012]7052)the National Scientific Research Project for Statistics(2012LZ054)
文摘As the web-server based business is rapidly developed and popularized, how to evaluate and improve the reliability of web-servers has been extremely important. Although a large num- ber of software reliability growth models （SRGMs）, including those combined with multiple change-points （CPs）, have been available, these conventional SRGMs cannot be directly applied to web soft- ware reliability analysis because of the complex web operational profile. To characterize the web operational profile precisely, it should be realized that the workload of a web server is normally non-homogeneous and often observed with the pattern of random impulsive shocks. A web software reliability model with random im- pulsive shocks and its statistical analysis method are developed. In the proposed model, the web server workload is characterized by a geometric Brownian motion process. Based on a real data set from IIS server logs of ICRMS website （www.icrms.cn）, the proposed model is demonstrated to be powerful for estimating impulsive shocks and web software reliability.
基金supported by the Shanghai Leading Academic Discipline Project (Grant No.J50103)
文摘Web service （WS） is an emerging software technology, especially acting an important role in cloud computing. The WS choreography description language （WS-CDL） is the standard for modeling the observable behavior of WS composition across multiple participants from a global point of view. However, it lacks of a formal semantics and could easily lead to misunderstanding and different implementations. In this paper, the WS-CDL based specifications are formally extracted in a communicating sequential process supporting a formal approach to checking WS models. In addition, formalisms and model checking are explicitly illustrated through a simple but non-trivial example with the help of model checker process analysis toolkit （PAT）.
基金Supported by Foundation of High Tech Project ofJiangsu (BG2004034)
文摘A novel semantic model of Web service descrip tion and discovery was proposed through an extension for profile model of Web ontology language for services （OWL-S） in this paper. Similarity matching of Web services was implemented through computing weighted summation of semantic similarity value based on specific domain ontology and dynamical satisfy extent evaluation for quality of service （QoS）. Experiments show that the provided semantic matching model is efficient.
基金Project supported by the Open Foundation of State Key Laboratory of Software Engineering(Grant No.SKLSE20080712)the National Natural Science Foundation of China(Grant No.60970007)+2 种基金the National Basic Research Program of China(Grant No.2007CB310800)the Shanghai Leading Academic Discipline Project(Grant No.J50103)the Science and Technology Commission of Shanghai Municipality(Grant No.09DZ2272600)
文摘Model checking techniques have been widely used in verifying web service compositions to ensure the trustworthi- ness. However, little research has focused on testing web services. Based on the research of model checking techniques~ we propose a model checking based approach for testing web service composition which is described by using the web services choreography description language （WS-CDL）. According to worldwide web consortium （W3C） candidate recommendation, the WS-CDL specification provides a language for characterizing interactions between distinct web services using XML. Since the behaviors of web service composition are asynchronous, distributed, low-coupled and platform independent, we employ the guarded automata （GA） model for specifying the composition described in WS-CDL and using the simple promela interpreter （SPIN） model checker for detecting the collaborations of web services. Test cases can be transformed from counterexamples generated by SPIN using adequacy criteria. In this paper we apply the transition coverage criterion for generating counterex- amples. To illustrate our approach, we set ＂E-commerce service system＂ as an example for demonstrating how test cases can be generated using SPIN for compositions specified in WS-CDL.
文摘The usability of an interface is a fundamental issue to elucidate. Many researchers argued that many usability results and recommendations lack empirical and experimental data. In this research, the usability of the web pages is evaluated using several carefully selected statistical models. Universities web pages are chosen as subjects for this work for ease of comparison and ease of collecting data. A series of experiments has been conducted to investigate into the usability and design of the universities web pages. Prototype web pages have been developed according to the structured methodologies of web pages design and usability. Universities web pages were evaluated together with the prototype web pages using a questionnaire which was designed according to the Human Computer Interactions (HCI) heuristics. Nine (users) respondents’ variables and 14 web pages variables (items) were studied. Stringent statistical analysis was adopted to extract the required information to form the data acquired, and augmented interpretation of the statistical results was followed. The results showed that the analysis of variance (ANOVA) procedure showed there were significant differences among the universities web pages regarding most of the 23 items studied. Duncan Multiple Range Test (DMRT) showed that the prototype usability performed significantly better regarding most of the items. The correlation analysis showed significant positive and negative correlations between many items. The regression analysis revealed that the most significant factors (items) that contributed to the best model of the universities web pages design and usability were: multimedia in the web pages, the web pages icons (alone) organisation and design, and graphics attractiveness. The results showed some of the limitations of some heuristics used in conventional interface systems design and proposed some additional heuristics in web pages design and usability.
文摘The emerging Model-Driven Engineering (MDE) paradigm advocates the use of models as first-class citizens in the software development process, while artifacts such as documentation and source-code can be quickly produced from those models by using automated transformations. Even though many MDE-oriented approaches, languages and tools have been developed in the recent past, there is no standard that concretely defines a specific sequence of steps to obtain a functional software system from a model. Thus, the existing approaches present numerous differences among themselves, because each one handles the problems inherent to software development in its own way. This paper presents and discusses a reference model for the comparative study of current MDE approaches in the scope of web-application development. This reference model focuses on relevant aspects such as modeling language scope (domain, business-logic, user-interface), usage of patterns, separation of concerns, model transformations, tool support, and deployment details like web-platform independence and traditional programming required. The ultimate goal of this paper is to determine the aspects that will be of greater importance in future web-oriented MDE languages.
文摘Model-Driven Engineering (MDE) by reframing software development as the transformation of high-level models, promises lots of gains to Software Engineering in terms of productivity, quality and reusability. Although a number of empirical studies have established the reality of these gains, there are still lots of reluctances toward the adoption of MDE in practice. This resistance can be explained by several technological and social factors among which a natural scepticism toward novel approaches. In this paper we attempt to provide arguments to help alleviate this scepticism by conducting an assessment of a MDE approach. Our goal is to show that although this MDE is novel, it retains similarities with the conventional Software Engineering approach while automating aspects of it.
