Constraint based program analysis is widely used in program validation, program vulnerability analysis, etc. This paper proposes a temporal correlation function to protect programs from analysis. The temporal correlat...Constraint based program analysis is widely used in program validation, program vulnerability analysis, etc. This paper proposes a temporal correlation function to protect programs from analysis. The temporal correlation function can be applied to resist against both static and dynamic function summary and eoncolie testing. What＇ s more, the temporal correlation function can produce different outputs even with same input. This feature can be used to damage the premise of function summary as well as prevent concolie testing process to run the new branch with new input. Experiment results show that this method can reduce efficiency and path coverage of concolic testing, while greatly in- creasing the difficulty of constraint based program analysis.展开更多
Considered a crucial skill in the 21st century,collaborative problem solving(CPS)has been an essential development task for preschool children.This study analyzes preschool children’s discourse in the project-based l...Considered a crucial skill in the 21st century,collaborative problem solving(CPS)has been an essential development task for preschool children.This study analyzes preschool children’s discourse in the project-based learning(PBL)process and presents the following findings.Firstly,in the collaborative dimension,the frequency of children’s discourse on establishing and maintaining shared understanding(U)and taking appropriate action to solve the problem(A)is relatively high,while that on establishing and maintaining team organization(O)is relatively low.Secondly,in the problem solving dimension,the frequency of children’s discourse on planning and executing(P&E)is the highest,while that on monitoring and reflecting(M&R)is the lowest.Thirdly,in terms of turn taking patterns,self-selection accounts for a significantly higher proportion than allocation and continuation.Overall,preschool children’s CPS is characterized by loose collaboration and multilinear problem solving.They are usually keener to strive for opportunities to express their views but lack attention to others’speeches.At the same time,they can constantly come up with new problem solving plans and actions but rarely reflect on their feasibility and actual effects.In addition to children’s collaborative role,teachers’intervention can also impact the CPS processes.Therefore,teachers are recommended to provide children with opportunities for CPS and strengthen monitoring,guidance,and support in children’s CPS processes to facilitate better child engagement in CPS.展开更多
聚焦于球铰链定位压紧装置,运用发明问题解决理论(theory of inventive problem solving,TRIZ)展开创新设计。首先分析传统球铰链生产工艺存在的问题,实现自动化替代创新设计专用球铰链定位压紧装置,通过因果分析得出该装置达到预计效...聚焦于球铰链定位压紧装置,运用发明问题解决理论(theory of inventive problem solving,TRIZ)展开创新设计。首先分析传统球铰链生产工艺存在的问题,实现自动化替代创新设计专用球铰链定位压紧装置,通过因果分析得出该装置达到预计效果将面临的技术难点,基于TRIZ理论的矛盾分析、物场分析等方法,确定技术矛盾与物理矛盾关键要点,挖掘出创新解的方法。通过TRIZ工具引导,提出一系列创新设计方案,涵盖球座精准定位结构设计和球压盖随动定位结构设计。经实验验证与实际应用效果评估,设计的球铰链定位压紧装置满足定位精度需求,能实现稳定均匀的压紧力输出,有效改善了操作的便捷性,提高了生产效率,为相关领域球铰链定位压紧作业提供了更优的解决方案。展开更多
有源滤波器(Active Power Filter,APF)是近年来提出的新型无功、谐波补偿装置。文章介绍了有源滤波器的原理、结构,有源滤波装置的发展,各种有源滤波装置的特性及其在电力系统中的应用。目前有源滤波器研究工作的关键是进一步提高有源...有源滤波器(Active Power Filter,APF)是近年来提出的新型无功、谐波补偿装置。文章介绍了有源滤波器的原理、结构,有源滤波装置的发展,各种有源滤波装置的特性及其在电力系统中的应用。目前有源滤波器研究工作的关键是进一步提高有源滤波器在生产实践中的应用水平,促进科研成果向工业成型产品的快速转化。展开更多
基金Supported by the National Natural Science Foundation of China(No.61121061)National Key Technology R&D Program(No.2012BAH38B02,2012BAH06B00)
文摘Constraint based program analysis is widely used in program validation, program vulnerability analysis, etc. This paper proposes a temporal correlation function to protect programs from analysis. The temporal correlation function can be applied to resist against both static and dynamic function summary and eoncolie testing. What＇ s more, the temporal correlation function can produce different outputs even with same input. This feature can be used to damage the premise of function summary as well as prevent concolie testing process to run the new branch with new input. Experiment results show that this method can reduce efficiency and path coverage of concolic testing, while greatly in- creasing the difficulty of constraint based program analysis.
基金funded by the Zhejiang Provincial Educational Science Planning Project“Reconstructing Young Children’s Learning Experience:Research on the Construction and Practice of Sustainable Development Curriculum in Kindergarten”(No.2020SCG202).
文摘Considered a crucial skill in the 21st century,collaborative problem solving(CPS)has been an essential development task for preschool children.This study analyzes preschool children’s discourse in the project-based learning(PBL)process and presents the following findings.Firstly,in the collaborative dimension,the frequency of children’s discourse on establishing and maintaining shared understanding(U)and taking appropriate action to solve the problem(A)is relatively high,while that on establishing and maintaining team organization(O)is relatively low.Secondly,in the problem solving dimension,the frequency of children’s discourse on planning and executing(P&E)is the highest,while that on monitoring and reflecting(M&R)is the lowest.Thirdly,in terms of turn taking patterns,self-selection accounts for a significantly higher proportion than allocation and continuation.Overall,preschool children’s CPS is characterized by loose collaboration and multilinear problem solving.They are usually keener to strive for opportunities to express their views but lack attention to others’speeches.At the same time,they can constantly come up with new problem solving plans and actions but rarely reflect on their feasibility and actual effects.In addition to children’s collaborative role,teachers’intervention can also impact the CPS processes.Therefore,teachers are recommended to provide children with opportunities for CPS and strengthen monitoring,guidance,and support in children’s CPS processes to facilitate better child engagement in CPS.
文摘聚焦于球铰链定位压紧装置,运用发明问题解决理论(theory of inventive problem solving,TRIZ)展开创新设计。首先分析传统球铰链生产工艺存在的问题,实现自动化替代创新设计专用球铰链定位压紧装置,通过因果分析得出该装置达到预计效果将面临的技术难点,基于TRIZ理论的矛盾分析、物场分析等方法,确定技术矛盾与物理矛盾关键要点,挖掘出创新解的方法。通过TRIZ工具引导,提出一系列创新设计方案,涵盖球座精准定位结构设计和球压盖随动定位结构设计。经实验验证与实际应用效果评估,设计的球铰链定位压紧装置满足定位精度需求,能实现稳定均匀的压紧力输出,有效改善了操作的便捷性,提高了生产效率,为相关领域球铰链定位压紧作业提供了更优的解决方案。
文摘有源滤波器(Active Power Filter,APF)是近年来提出的新型无功、谐波补偿装置。文章介绍了有源滤波器的原理、结构,有源滤波装置的发展,各种有源滤波装置的特性及其在电力系统中的应用。目前有源滤波器研究工作的关键是进一步提高有源滤波器在生产实践中的应用水平,促进科研成果向工业成型产品的快速转化。
