综合业务城域网IEEE802.5预约级协议改进策略

预约是局域网(LAN)中常见的存取方式,尤其以环形LAN的IEEE802.5预约级协议著称。为了在综合业务的环形城域网(MAN)中利用预约级协议,必须考虑综合业务的特点,对IEEE802.5预约级协议进行改进。其出发点是既要尽可能保证高优先级信息能提前预约,又要防止出现低优先级信息(特别是最低优先级信息)长时间得不到发送的局面。该文提出的高预约级中断策略,比较合理地解决了这一问题。其实质是在合理范围内牺牲高优先级业务的服务质量,换来部分提高低优先级业务的服务质量。模拟实验表明,改进后的IEEE802.5预约级策略适合于综合业务MAN的利用。     

Fermi surface nesting and possibility of orbital ordering in FeO

Remarkable inter-band nesting in FeO Fermi surface, hints to examine energy of orbitally ordered states, which turn out to be more stable. We propose this method as a general scheme to check for possibility of orbital ordering in first principle calculations, and demonstrate it for known examples, LiVO₂ and LaMnO₃.     

多品种小批量元器件的统计过程控制

针对国内许多元器件生产企业普遍存在的多品种小批量订货情况,如何使小批量产品保持大批量产品同样的质量和可靠性成为要研究的问题。文章介绍了统计过程控制技术原理及评价流程,分析了多品种小批量元器件生产存在的数据量不足和工艺参数嵌套性的统计问题,并给出了解决方法,依据嵌套回归的数学统计原理,以元器件生产中广泛采用的电镀工序为例,应用嵌套回归控制图对镀层厚度参数进行数据分析处理,以判断工序过程是否处于统计受控状态。     

Length distributions of edges in planar stationary and isotropic STIT tessellations

Stationary and isotropic random tessellations of the euclidean plane are studied which have the characteristic property to be stable with respect to iteration (or nesting), STIT for short. Since their cells are not in a face-to-face position, three different types of linear segments appear. For all the types the distribution of the length of the typical segment is given. The text was submitted by the authors in English.     

DMA接口支持板的设计

DMA技术在提高数据传送速率方面有着重要作用,特别是对于高速率数据传送。目前计算机少有支持存储器与外设之间DMA传送的商用扩展板。为此,本文介绍了用于某气象雷达计算机终端与信号处理之间高速数据传送的DMA接口支持板的设计思路和实现方法,并给出了软件流程图和汇编程序。     

用于雷达信号处理模块化的控制程序的设计

介绍在模块化研究中。如何利用C Builder来编制功能模块控制界面,并通过PC机与单片机的串行通信.完成对各模块的实时控制,以达到系统控制的目的。     

Orthogonal Partitions in Designed Experiments

A survey is given of the statistical theory of orthogonal partitions on a finite set. Orthogonality, closure under suprema, and one trivial partition give an orthogonal decomposition of the corresponding vector space into subspaces indexed by the partitions. These conditions plus uniformity, closure under infima and the other trivial partition give association schemes. Examples covered by the theory include Latin squares, orthogonal arrays, semilattices of subgroups, and partitions defined by the ancestral subsets of a partially ordered set (the poset block structures).Isomorphism, equivalence and duality are discussed, and the automorphism groups given in some cases. Finally, the ideas are illustrated by some examples of real experiments.Dedicated to Hanfried Lenz on the occasion of his 80th birthday.     

在MPC555中实现从RAM的快速引导

介绍了PowerPC系列微处理器的异常和中断。同时以MPC555为例对嵌入式系统从ROM和RAM中的引导特点及技术实现方法进行了比较 ,给出了MPC555从RAM快速引导的实现方法     

小批次元器件SPC过程中嵌套回归方法研究

元器件企业都存在订货量小、批次多的情况,在保证订货任务完成的情况下,如何能向用户提交这些元器件生产过程的质量波动数据,是需要解决的问题。该文主要基于嵌套回归的数学统计原理,以混合集成电路印刷工艺为例,对膜厚参数进行嵌套回归的统一化处理,结果表明应用嵌套回归数学方法处理后生成的控制图能比应用传统控制图更能真实地反映工艺受...     

A RECTANGULAR SHELL ELEMENT FORMULATION WITH A NEW MULTI-RESOLUTION ANALYSIS

A multi-resolution rectangular shell element with membrane-bending based on the Kirchhoff-Love theory is proposed. The multi-resolution analysis （MRA） framework is formulated out of a mutually nesting displacement subspace sequence, whose basis functions are constructed of scaling and shifting on the element domain of basic node shape functions. The basic node shape functions are constructed from shifting to other three quadrants around a specific node of a basic element in one quadrant and joining the corresponding node shape functions of four elements at the specific node. The MRA endows the proposed element with the resolution level （RL） to adjust the element node number, thus modulating structural analysis accuracy accordingly. The node shape functions of Kronecker delta property make the treatment of element boundary condition quite convenient and enable the stiffness matrix and the loading column vectors of the proposed element to be automatically acquired through quadraturing around nodes in RL adjusting. As a result, the traditional 4-node rectangular shell element is a mono-resolution one and also a special case of the proposed element. The accuracy of a structural analysis is actually determined by the RL, not by the mesh. The simplicity and clarity of node shape function formulation with the Kronecker delta property, and the rational MRA enable the proposed element method to be implemented more rationally, easily and efficiently than the conventional mono-resolution rectangular shell element method or other corresponding MRA methods.