Computational grids (CGs) aim to offer pervasive access to a diverse collection of geographically distributed resources owned by different serf-interested agents or organizations. These agents may manipulate the res...Computational grids (CGs) aim to offer pervasive access to a diverse collection of geographically distributed resources owned by different serf-interested agents or organizations. These agents may manipulate the resource allocation algorithm in their own benefit, and their selfish behavior may lead to severe performance degradation and poor efficiency. In this paper, game theory is introduced to solve the problem of barging for resource collection in heterogeneous distributed systems. By using the Cournot model that is an important model in static and complete information games, the algorithm is optimized in order to maximize the benefit. It can be seen that the approach is more suitable to the real situation and has practical use. Validity of the solutions is shown.展开更多
Purpose:Preserving and caring for nature in a sustainable way has long been part of Swedish preschool practice.However,recently has it been explicitly referenced in the Swedish preschool curriculum with the goal of in...Purpose:Preserving and caring for nature in a sustainable way has long been part of Swedish preschool practice.However,recently has it been explicitly referenced in the Swedish preschool curriculum with the goal of incorporating sustainability holistically and coherently in all areas of children’s daily preschool experiences through play,care,and education.Research has revealed a potential roadblock to achieving this goal;the difficulty connecting the three inextricably linked dimensions of sustainability:ecological,social-cultural,and economic.The purpose is to generate knowledge about preschool teachers’professional understanding of education for sustainable development(ESD)in early childhood education(ECE)by implementing and enhancing the operationalization of such work in four Swedish preschools.Design/Approach/Methods:The design of the study rests on the involvement of teachers in work where they created sustainability activities supported by the Environmental Rating Scale for Sustainable Development in Early Childhood(ERS-SDEC).The data consist of teachers’narratives and interviews,and a qualitative content analysis is used from which a number of themes emerged.Findings:The initial interviews foregrounded three themes:the value of collective resources,the wonders of nature,and a global world.At the end of the project,the teachers’expressions of their practice revealed three qualitatively transformed themes:broadened awareness of sustainability,ecology embracing culture,and expanded perspectives,as factors of ESD.Originality/Value:Teachers did increase their awareness of working with children and expressed a strength in using each other as collective resources.By that,their professional understandings of ESD in preschool developed.展开更多
Despite the availability of garbage collectors, programmers must manually manage non-memory finite system resources such as file descriptors. Resource leaks can gradually consume all available resources and cause prog...Despite the availability of garbage collectors, programmers must manually manage non-memory finite system resources such as file descriptors. Resource leaks can gradually consume all available resources and cause programs to raise resource exhaustion exceptions. However, programmers commonly provide no effective recovery approach for resource exhaustion exceptions, which often causes programs to halt without completing their tasks. In this paper, we propose to automatically recover programs from resource exhaustion exceptions caused by resource leaks. We transform programs to catch resource exhaustion exceptions, collect leaked resources, and then retry the failure code. A resource collector is designed to identify leaked resources and safely release them. We implement our approach for Java programs. Experimental results show that our approach can successfully handle resource exhaustion exceptions caused by reported resource leaks and allow programs to complete their tasks with an average execution time increase of 2.52% and negligible bytecode size increase.展开更多
基金Project supported by the Science Foundation of Shanghai Municipal Commission of Science and Technology(Grant No.00JC14052)
文摘Computational grids (CGs) aim to offer pervasive access to a diverse collection of geographically distributed resources owned by different serf-interested agents or organizations. These agents may manipulate the resource allocation algorithm in their own benefit, and their selfish behavior may lead to severe performance degradation and poor efficiency. In this paper, game theory is introduced to solve the problem of barging for resource collection in heterogeneous distributed systems. By using the Cournot model that is an important model in static and complete information games, the algorithm is optimized in order to maximize the benefit. It can be seen that the approach is more suitable to the real situation and has practical use. Validity of the solutions is shown.
文摘Purpose:Preserving and caring for nature in a sustainable way has long been part of Swedish preschool practice.However,recently has it been explicitly referenced in the Swedish preschool curriculum with the goal of incorporating sustainability holistically and coherently in all areas of children’s daily preschool experiences through play,care,and education.Research has revealed a potential roadblock to achieving this goal;the difficulty connecting the three inextricably linked dimensions of sustainability:ecological,social-cultural,and economic.The purpose is to generate knowledge about preschool teachers’professional understanding of education for sustainable development(ESD)in early childhood education(ECE)by implementing and enhancing the operationalization of such work in four Swedish preschools.Design/Approach/Methods:The design of the study rests on the involvement of teachers in work where they created sustainability activities supported by the Environmental Rating Scale for Sustainable Development in Early Childhood(ERS-SDEC).The data consist of teachers’narratives and interviews,and a qualitative content analysis is used from which a number of themes emerged.Findings:The initial interviews foregrounded three themes:the value of collective resources,the wonders of nature,and a global world.At the end of the project,the teachers’expressions of their practice revealed three qualitatively transformed themes:broadened awareness of sustainability,ecology embracing culture,and expanded perspectives,as factors of ESD.Originality/Value:Teachers did increase their awareness of working with children and expressed a strength in using each other as collective resources.By that,their professional understandings of ESD in preschool developed.
基金supported by the National Natural Science Foundation of China(Nos.61379054 and 91318301)the National High-Tech R&D Program(863)of China(No.2012AA011201)
文摘Despite the availability of garbage collectors, programmers must manually manage non-memory finite system resources such as file descriptors. Resource leaks can gradually consume all available resources and cause programs to raise resource exhaustion exceptions. However, programmers commonly provide no effective recovery approach for resource exhaustion exceptions, which often causes programs to halt without completing their tasks. In this paper, we propose to automatically recover programs from resource exhaustion exceptions caused by resource leaks. We transform programs to catch resource exhaustion exceptions, collect leaked resources, and then retry the failure code. A resource collector is designed to identify leaked resources and safely release them. We implement our approach for Java programs. Experimental results show that our approach can successfully handle resource exhaustion exceptions caused by reported resource leaks and allow programs to complete their tasks with an average execution time increase of 2.52% and negligible bytecode size increase.