Contact reactions of guide surfaces of assembly interfaces lead to the decreasing of theirs lateral and angular misalignments. The focus of this paper is the development of algorithms for computation of guide surfaces...Contact reactions of guide surfaces of assembly interfaces lead to the decreasing of theirs lateral and angular misalignments. The focus of this paper is the development of algorithms for computation of guide surfaces contact forces with acceptable engineering accuracy for real time simulation of assembly operations. Therefore, each complex guide surface is described as a set of contacting elements. Each contacting element for one＇s part can be represented by a finite set of geometric primitives which geometry is described by low order algebraic equations. So contact conditions and geometric parameters for all pairs of primitives are determined by analytical expressions. Math models are developed for two classes of contact interaction. The first class includes all cases when each contacting surface has several degrees of freedom of motion. Therefore, contact reactions introduced into differential equations of motion are calculated by using contacting elements penetrations, stiffness and damping parameters. The second class corresponds to all cases when one of contacting surfaces has insignificant inertia and only one degree of freedom of relative displacement counteracted by a spring. Here contact reactions are calculated from spring tension with any practical accuracy. This is very useful in some practical applications. Presented algorithms provide real time simulation together with some approaches for reduction of redundant comnutations.展开更多
In shared-memory bus-based multiprocessors, when the number of processors grows, the processors spend an increasing amount of time waiting for access to the bus (and shared memory). This contention reduces the perform...In shared-memory bus-based multiprocessors, when the number of processors grows, the processors spend an increasing amount of time waiting for access to the bus (and shared memory). This contention reduces the performance of processors and imposes a limitation of the number of processors that can be used efficiently in bus-based systems. Since the multi-processor’s performance depends upon many parameters which affect the performance in different ways, timed Petri nets are used to model shared-memory bus-based multiprocessors at the instruction execution level, and the developed models are used to study how the performance of processors changes with the number of processors in the system. The results illustrate very well the restriction on the number of processors imposed by the shared bus. All performance characteristics presented in this paper are obtained by discrete-event simulation of Petri net models.展开更多
随着5G(5th generation mobile networks)技术的日益成熟和普及,其高速率、低时延、大连接的特点为大专旅游教学带来了前所未有的新机遇。本文旨在探讨基于5G技术的大专旅游教学系统的设计与实现方法,以提高教学质量,满足现代旅游教育...随着5G(5th generation mobile networks)技术的日益成熟和普及,其高速率、低时延、大连接的特点为大专旅游教学带来了前所未有的新机遇。本文旨在探讨基于5G技术的大专旅游教学系统的设计与实现方法,以提高教学质量,满足现代旅游教育的需求。系统结合旅游学科的特点,通过5G技术实现教学资源共享、实时互动与协作学习,为大专旅游教学提供了有效的技术支持。展开更多
文摘Contact reactions of guide surfaces of assembly interfaces lead to the decreasing of theirs lateral and angular misalignments. The focus of this paper is the development of algorithms for computation of guide surfaces contact forces with acceptable engineering accuracy for real time simulation of assembly operations. Therefore, each complex guide surface is described as a set of contacting elements. Each contacting element for one＇s part can be represented by a finite set of geometric primitives which geometry is described by low order algebraic equations. So contact conditions and geometric parameters for all pairs of primitives are determined by analytical expressions. Math models are developed for two classes of contact interaction. The first class includes all cases when each contacting surface has several degrees of freedom of motion. Therefore, contact reactions introduced into differential equations of motion are calculated by using contacting elements penetrations, stiffness and damping parameters. The second class corresponds to all cases when one of contacting surfaces has insignificant inertia and only one degree of freedom of relative displacement counteracted by a spring. Here contact reactions are calculated from spring tension with any practical accuracy. This is very useful in some practical applications. Presented algorithms provide real time simulation together with some approaches for reduction of redundant comnutations.
文摘In shared-memory bus-based multiprocessors, when the number of processors grows, the processors spend an increasing amount of time waiting for access to the bus (and shared memory). This contention reduces the performance of processors and imposes a limitation of the number of processors that can be used efficiently in bus-based systems. Since the multi-processor’s performance depends upon many parameters which affect the performance in different ways, timed Petri nets are used to model shared-memory bus-based multiprocessors at the instruction execution level, and the developed models are used to study how the performance of processors changes with the number of processors in the system. The results illustrate very well the restriction on the number of processors imposed by the shared bus. All performance characteristics presented in this paper are obtained by discrete-event simulation of Petri net models.
文摘随着5G(5th generation mobile networks)技术的日益成熟和普及,其高速率、低时延、大连接的特点为大专旅游教学带来了前所未有的新机遇。本文旨在探讨基于5G技术的大专旅游教学系统的设计与实现方法,以提高教学质量,满足现代旅游教育的需求。系统结合旅游学科的特点,通过5G技术实现教学资源共享、实时互动与协作学习,为大专旅游教学提供了有效的技术支持。
