The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by...The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element（FE） simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology（RSM）.The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components.展开更多
Due to the fact that the existing web service description methods cannot address the issue of service reuse of various levels of granularity, the concept of service component is introduced, which packages together web...Due to the fact that the existing web service description methods cannot address the issue of service reuse of various levels of granularity, the concept of service component is introduced, which packages together web services and choreography, and their operations and properties are presented in a consistent and uniform manner. Service components are published externally as normal web services and can thus be employed by webbased applications. In order to improve reusability and testability of service components, the concept of composition pattern is also proposed, which presents the relationships among service components. The relationships and relationship compositions have a rigorous semantic, so that composite components can be validated at the configuration stage. The composition patterns support to integrate service components of various levels of granularity. Experience indicates that the application assembly can effectively be conducted by understanding, selecting, and reusing components easily.展开更多
如何充分利用原有系统的资源,建立开放灵活、低代价的系统已成为信息化建设的关键。面向服务的体系结构(SOA)为解决分布式环境中软件重用、扩展和提高软件开发效率提供了解决方案。W eb Serv ices是构建SOA的核心技术,服务是SOA的基本单...如何充分利用原有系统的资源,建立开放灵活、低代价的系统已成为信息化建设的关键。面向服务的体系结构(SOA)为解决分布式环境中软件重用、扩展和提高软件开发效率提供了解决方案。W eb Serv ices是构建SOA的核心技术,服务是SOA的基本单元;采用基于W eb serv ice B ind ing与Java Com ponent的SCA规范构建SOA,能自然有效地实现服务间的松散耦合。结合电信项目开发探讨了SOA的有关概念与技术,并给出了在国产L inux环境下基于W eb serv ice B ind ing和Java Com ponent的SCA规范构建SOA的部分实现。展开更多
Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractic...Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractical for users to specify quantitative and exact preferences. Moreover, due to that Quality of Service (QoS) attributes are often interrelated, existing Web service selection approaches which employ weighted summation of QoS attribute values to compute the overall QoS of Web services may produce inaccurate results, since they do not take correlations among QoS attributes into account. To resolve these problems, a Web service selection framework considering user's preference priority is proposed, which incorporates a searching mechanism with QoS range setting to identify services satisfying the user's QoS constraints. With the identified service candidates, based on the idea of Principal Component Analysis (PCA), an algorithm of Web service selection named PCA-WSS (Web Service Selection based on PCA) is proposed, which can eliminate the correlations among QoS attributes and compute the overall QoS of Web services accurately. After computing the overall QoS for each service, the algorithm ranks the Web service candidates based on their overall QoS and recommends services with top QoS values to users. Finally, the effectiveness and feasibility of our approach are validated by experiments, i.e. the selected Web service by our approach is given high average evaluation than other ones by users and the time cost of PCA-WSS algorithm is not affected acutely by the number of service candidates.展开更多
Geographic information system(GIS)technology is a combination of computer’s graphic and database to store and process spatial information.According to the users’ demands,GIS exports the exact geographic information ...Geographic information system(GIS)technology is a combination of computer’s graphic and database to store and process spatial information.According to the users’ demands,GIS exports the exact geographic information and related in- formation for users with map and description through associating geographic place and related attributes.Based on the existing pop- ular technology,this paper presents a distributed web GIS application based on component technology and fractal image compres- sion.It presents the basic framework of the proposed system at first,and then discusses the key technology of implementing this sys- tem;finally it designs a three-layer WEB GIS instance using VC++ATL based on Geo Beans.The example suggests the proposed design is correct,feasible and valid.展开更多
基金the support of the National Natural Science Foundation of China(Nos.51605388,51675433)111 Project(B08040)+2 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NWPU)in China(Grant No.131-QP-2015)the Fundamental Research Funds for the Central Universitiesthe Open Research Fund of State Key Laboratory of Materials Processing and Die&Mold Technology at Huazhong University of Science and Technology
文摘The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element（FE） simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology（RSM）.The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components.
基金The National Basic Research Program of China (973Program) (No.1999032710).
文摘Due to the fact that the existing web service description methods cannot address the issue of service reuse of various levels of granularity, the concept of service component is introduced, which packages together web services and choreography, and their operations and properties are presented in a consistent and uniform manner. Service components are published externally as normal web services and can thus be employed by webbased applications. In order to improve reusability and testability of service components, the concept of composition pattern is also proposed, which presents the relationships among service components. The relationships and relationship compositions have a rigorous semantic, so that composite components can be validated at the configuration stage. The composition patterns support to integrate service components of various levels of granularity. Experience indicates that the application assembly can effectively be conducted by understanding, selecting, and reusing components easily.
文摘如何充分利用原有系统的资源,建立开放灵活、低代价的系统已成为信息化建设的关键。面向服务的体系结构(SOA)为解决分布式环境中软件重用、扩展和提高软件开发效率提供了解决方案。W eb Serv ices是构建SOA的核心技术,服务是SOA的基本单元;采用基于W eb serv ice B ind ing与Java Com ponent的SCA规范构建SOA,能自然有效地实现服务间的松散耦合。结合电信项目开发探讨了SOA的有关概念与技术,并给出了在国产L inux环境下基于W eb serv ice B ind ing和Java Com ponent的SCA规范构建SOA的部分实现。
基金Supported by the National Natural Science Foundation of China(No.90818004and61100054)Program for New Century Excellent Talents in University(No.NCET-10-0140)+1 种基金Excellent Youth Foundation of Hunan Scientific Committee(No.11JJ1011)Scientific Research Fundof Hunan Educational Committee(No.09K085and11B048)
文摘Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractical for users to specify quantitative and exact preferences. Moreover, due to that Quality of Service (QoS) attributes are often interrelated, existing Web service selection approaches which employ weighted summation of QoS attribute values to compute the overall QoS of Web services may produce inaccurate results, since they do not take correlations among QoS attributes into account. To resolve these problems, a Web service selection framework considering user's preference priority is proposed, which incorporates a searching mechanism with QoS range setting to identify services satisfying the user's QoS constraints. With the identified service candidates, based on the idea of Principal Component Analysis (PCA), an algorithm of Web service selection named PCA-WSS (Web Service Selection based on PCA) is proposed, which can eliminate the correlations among QoS attributes and compute the overall QoS of Web services accurately. After computing the overall QoS for each service, the algorithm ranks the Web service candidates based on their overall QoS and recommends services with top QoS values to users. Finally, the effectiveness and feasibility of our approach are validated by experiments, i.e. the selected Web service by our approach is given high average evaluation than other ones by users and the time cost of PCA-WSS algorithm is not affected acutely by the number of service candidates.
文摘Geographic information system(GIS)technology is a combination of computer’s graphic and database to store and process spatial information.According to the users’ demands,GIS exports the exact geographic information and related in- formation for users with map and description through associating geographic place and related attributes.Based on the existing pop- ular technology,this paper presents a distributed web GIS application based on component technology and fractal image compres- sion.It presents the basic framework of the proposed system at first,and then discusses the key technology of implementing this sys- tem;finally it designs a three-layer WEB GIS instance using VC++ATL based on Geo Beans.The example suggests the proposed design is correct,feasible and valid.
