A non-canonical example to support P is not equal to NP

The more unambiguous statement of the P versus NP problem and the judgement of its hardness, are the key ways to find the full proof of the P versus NP problem. There are two sub-problems in the P versus NP problem. The first is the classifications of different mathematical problems (languages), and the second is the distinction between a non-deterministic Turing machine (NTM) and a deterministic Turing machine (DTM). The process of an NTM can be a power set of the corresponding DTM, which proves that the states of an NTM can be a power set of the corresponding DTM. If combining this viewpoint with Cantor’s theorem, it is shown that an NTM is not equipotent to a DTM. This means that "generating the power set P(A) of a set A" is a non-canonical example to support that P is not equal to NP.     

论学习交往的教育意义、分类及对策

交往是人们普遍的存在方式和发展方式;教育作为一种促进人的发展的特殊社会实践活动,更典型地体现了人类活动的这种特点。因而教育不仅是要学生学会维持其生存和发展的知识技能,更需要使学生学会与人交往。在教育视野中,不仅要注意“交往”的工具性价值,同样应看到它的目的性价值,即把交往当作学生学习的目的,只有这样才能培养出全面和谐发展的人。     

中学生数学归纳推理的发展研究

发展学生的归纳推理能力是数学课程的重要目标.初中生数学归纳推理的发展状况为:信息表征的类型随着知识量的增加而增加;归纳猜想随年级的升高而呈现缓慢增长趋势;假设检验随年级的增长并不显著;归纳推理与演绎推理在各年级中的发展不均衡.因此,在教学中加强归纳推理的教育与心理研究是十分必要也是刻不容缓的.     

语篇理解中三种推论理论的评析

语篇理解有三种推论理论:构成主义范式、最低限要求者假说和语义后搜索理论。每种理论都产生于不同背景下,支持其理论的实验数据也不同。了解每种理论使用条件和其局限范围,合理评析每种理论的优缺点,是正确应用三种推论理论前提。     

经济法主体与民法主体的比较研究

民法主体规范的不科学现状 ,对经济法主体理论的建立形成了障碍。文章从几个基本假设入手 ,试分析了经济法与民法在立法的本位、价值取向、作用等各方面的差异性 ,从而为经济法主体理论的建立提供了帮助。     

浅析二难推理

二难推理是假言选言推理中的一种形式,是一种特殊的辩论工具.传统逻辑学认为二难推理是由两个或两个以上的充分条件假言判断和一个选言肢数与假言判断个数相等的相容选言判断作前提推出一个简单判断或选言判断的推理形式.然而,二难推理的假言前提不仅有充分条件,而且有必要条件和充要条件;选言前提有相容的,也有不相容的.二难推理共有28种有效推理形式.     

二语语用能力发展的相关理论模式述评

近年来,第二语言语用能力发展的研究正日益受到关注。社会文化理论和注意假设分别从社交和认知层面解释了在二语环境下语用能力的习得规律和习得环境,同时,该领域的研究成果对我国外语教学带来了启迪,但两种理论模式也存在着各自的局限性。     

狭义相对论中的“时钟假设”和“长度假设”

分析了狭义相对论中的钟慢效应和尺缩效应只与速度有关而与加速度无关。     

Analysis of tensioned membrane structures considering cable sliding

In routine design of tensioned membrane st ructures, the membrane is gen erally modeled using space membrane elements and the cables by space cable eleme nts, with no sliding allowed between the membrane and the cables. On the other h and, large deflections are expected and sliding between the membrane and the cab les is inevitable. In the present paper, the general finite element code ABAQUS was employed to investigate the influence of cable sliding on membrane surface o n the structural behavior. Three analysis models were devised to fulfill this pu rpose: (1) The membrane element shares nodes with the cable element; (2) The cab le can slide on the membrane surface freely (without friction) and (3) The cable can slide on the membrane surface, but with friction between the cable and the membrane. The sliding problem is modeled using a surface-based contact algorithm . The results from three analysis models are compared, showing that cable slidin g has only little influence on the structure shape and on the stress distributio ns in the membrane. The main influence of cable sliding may be its effect on the dynamic behavior of tensioned membrane structures.     

圆柱蜗杆传动计算机辅助分析与仿真

本文以计算机图学中曲线曲面理论为基础,以数值方法代替解析方法,将三维空间啮合问题简化为三维平面啮合问题,对磨削加工圆柱蜗杆传动的设计,预测并分析各种啮合质量,正确选择各种设计参数等项进行了研究,并形成了相应软件包.