程序设计中递归思想教学方法探讨

递归思想是程序设计中一种非常重要、有效的思想。许多有趣的算法可以用几行简单的递归函数来表达。然而学生在学习递归函数由于对其执行过程不了解,对递归思想似懂非懂,难以设计正确的递归函数。本文介绍自己在教授此内容时的几点经验,希望与同行共同探讨.     

递归程序的转换技术

提出了一种实用的递归程序转换技术,它可以方便地把递归函数转换成与之等价的非递归形式,已在DPS8/49机上实现。     

自底向上记录式Hanoi塔非递归算法

Hanoi塔问题的经典递归算法虽然代码量小,但时间复杂度却是指数级的,而且难以理解。该文基于Hanoi塔问题的递归思想,构造出Hanoi塔的树模型,仔细分析递归函数的调用参数和语句执行时盘子移动的顺序,巧妙地找到两者之间的对应关系,从而提出一种新的自底向上非递归算法。该算法逐一地记录下n从1开始时盘子从源柱到目标柱时经历过的移动轨迹,进而直接应用到n+1个盘子的移动问题。实验结果表明,该算法对应的代码易读且高效,时间复杂度降为O(n),是对Hanoi塔问题的非递归算法研究的进一步实践与探讨。     

递归函数浅析

介绍了递归函数和函数的递归调用概念，分析了汉诺塔问题函数的递归调用过程，并对递归和迭代进行了简要的比较     

递归算法在C/C＋＋程序设计中的描述与实现

递归是函数实现的一个很重要的环节，对许多复杂的问题，递归能提供简单、自然的解法。本文在对递归的概念进行介绍的基础上，重点讨论了递归的程序设计方法，并分析了递归函数的调用和回溯过程。     

基于有限递归和μ-算子的α-递归论

根据Ｂｌｕｍ，Ｓｈｕｂ和Ｓｍａｌｅ定义实数环上的计算模型中将递归和μ－算子限制在自然数上这一特点，提出了基于自然数上的递归定义和μ－算子。研究了在可允许序数α－上定义的可计算函数－弱α－递归函数的弱α－递归论的基本性质及其与α－递归论的差别，证明了每个弱α－递归函数是以自然数为参量关于取值α上的变量的多项式函数，并且每个弱α－递归可枚举集与自然数集的交集是递归可枚举的。     

一般递归函数定义中极小化次数问题的研究

研究了定义递归函数过程中极小化运算的次数问题，证实了任意一个递归函数可以从初始子数出发，经有限次复合，递归和至多一次极小化运算而得到。这一结论对计算复杂性理论有明显的意义。     

递归算法非递归化的一般规律

尽管递归算法具有结构简练、清晰、可读性强、正确性容易得到证明等优点，但递归算法在执行过程中会耗费太多时间和空间。为了追求算法的时空效率，特别是使用不支持递归的程序语言的情况下，必须将递归算法转化为非递归算法，问题才能得到有效解决。为此，给出了递归算法转化为非递归算法的一般方法，并以Hanoi塔问题、二叉树的中序遍历问题为例进行了详细地分析。     

关于Grzegorczyk第九问题

本文通过引进二重递归函数类的一种分层{Y_n}_(n∈∞),证明了借助于本原函数(后继函数、零函数和投影函数)以及原始递归和复合运算,如果仅增加有限多个二重递归函数作为开始函数,则不足以产生全体二重递归函数。     

λ－可定义函数的构造性解

λ－可定义函数的构造性解朱一清（东南大学计算机科学与工程系，南京２１００１８）根据Ｋｌｅｅｎｅ定理，凡λ－可定义的数论函数均是递归函数，反之亦然．因此，常借助于递归函数和递归定义来描述一个λ－可定义函数．一个λ－可定义的函数是λ－项所组成的集合中的一...     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that