Quantum Mechanics on Finite Groups

Although a few new results are presented, this is mainly a review article on the relationship between finite-dimensional quantum mechanics and finite groups. The main motivation for this discussion is the hidden subgroup problem of quantum computation theory. A unifying role is played by a mathematical structure that we call a Hilbert ^*-algebra. After reviewing material on unitary representations of finite groups we discuss a generalized quantum Fourier transform. We close with a presentation concerning position-momentum measurements in this framework.     

一种新的交通网络设计优化算法

交通网络设计问题是研究如何用定量的方法在已有交通网络上添加或扩容某些路段的问题.文章在回顾交通网络设计问题文献的基础上,提出了基于图论网络优化思想的解决该类问题的一种新思路,给出了启发式算法,并进行了算法复杂性分析,最后通过算例验证了其有效性.     

排序问题P2|prmp|Cmax在中断—重复模型下的调度

对于传统的中断-恢复模型下的P2｜prmp｜Cmax问题，已有最优调度规则。但中断-恢复模型并不是一般意义下的中断模型。在某些情况下，被中断的任务不能被简单的恢复加工，而是在该任务被重新加工之前必须有一定的延迟时间。延迟可能是该项任务的一部分（或者是全部）需要返工的时间。本文在研究了排序问题P2｜prmp｜Cmax在中断-重复模型下的调度，指出对于选择哪一个任务被中断的问题是NP—hard的；而对于如何处理被中断的任务的问题，指出当被中断任务的最初被加工时间由Xj增加为Xj＋△xj=Xj/（1-1/2aj）时，可使得两台处理机的时间表长相等，从而达到最优。最优时间表长为：Cmax^＊=1/2n∑j=1pj＋ajxj/（2-aj）。最后给出了在中断-重复模型下的调度规则。     

An efficient explicit framework for determining the lowest structural buckling load using Dynamic Relaxation method

This paper develops an e?cient explicit algorithm for calculating buckling load of structures. Here, the modified Dynamic Relaxation method is utilized so that the first structural buckling load is achieved. The proposed algorithm does not require solving any eigenvalue problem and runs by full vector and iterative operations. Moreover, the suggested procedure is general so that it could be utilized for both symmetric and unsymmetric structures without any additional calculations. For numerical verification, some columns and portal frames are analyzed and the calculated buckling loads are compared with the exact solution and other available approaches. Results show that the proposed algorithm has suitable accuracy and e?ciency that is useful for determining the lowest buckling load of each structure. Moreover, the effect of initial imperfection and time step size on the suggested framework is studies numerically.     

Organic Stereochemistry. Part 1. Symmetry Elements and Operations,Classification of Stereoisomers

This review initiates a general presentation of the principles of stereochemistry with special reference to medicinal compounds. The format is essentially identical with that of a previous Series of seven reviews on the Metabolism of Drugs and Other Xenobiotics published between October 2006 and October 2009 by B. T. and Stefanie Krämer in Chemistry & Biodiversity. Here, there will be eight reviews published in Helvetica Chimica Acta, to be grouped and published in book form together with some additional material. Part 1 introduces this new series by presenting and illustrating basic concepts on which the edifice of stereochemistry is built. At the most basic level of such foundations, we find symmetry as presented here in terms of its elements, operations, and point groups. This is followed by a classification of isomeric molecular structures, as well as a classification of steric relationships between molecular fragments.     

Analysis of quota assignment and time block duration in multi-block appointment systems

The objective of this study is to propose performance evaluatorsand optimizers for the quota appointment system in many hospitalsand clinics used to smooth the patient flow. This type of queueingsystem with finite population and controlled arrivals is studiedon a single server with exponential service time. Given a targetwaiting time set by the hospital, the quota assignment givingthe minimum chance of underachievement in each time block isderived using a dynamic programming approach. This enables exactcalculations of performance measures of expected waiting time,server overtime and congestion measured in headcount. The optimaltime block duration, in addition to the quota assignment, isexamined using an extended dynamic programming formulation.Special cases of absentees, late arrivals and re-entry patientsare then incorporated into the basic model. Performance measuresare evaluated through two approaches, according to the prioritiesof treatment for the special cases.     

Minimal clones generated by majority operations

The minimal majority functions of the four-element set are determined. Received October 10, 1997; accepted in final form February 8, 2000.     

Flexibility across and flexibility within: The domain of integer addition and subtraction

To better understand the role that flexibility plays in students’ success on integer addition and subtraction problems, we examined students’ flexibility when solving open number sentences. We define flexibility as the degree to which a learner uses more than one strategy to solve a single task when prompted, as well as the degree to which a learner changes strategies when solving a range of tasks to accommodate task differences. We introduce the categorizations of flexibility within and flexibility across to distinguish these two ways of operationalizing flexibility. We examined flexibility and performance within and among three groups of students — 2nd and 4th graders who had negative numbers in their numerical domains, 7th graders, and college-track 11th graders. Profiles of five students are shared to provide insight in relation to the quantitative findings.     

一些双联运算图的规范拉普拉斯谱

研究了基于剖分图、Q-图、R-图和全图的双联运算图的四类变型,给出了它们的规范拉普拉斯谱.所得结果推广了关于图的联运算的一些已有结果.