More restrictive Gray codes for some classes of pattern avoiding permutations

In a recent article [W.M.B. Dukes, M.F. Flanagan, T. Mansour, V. Vajnovszki, Combinatorial Gray codes for classes of pattern avoiding permutations, Theoret. Comput. Sci. 396 (2008) 35-49], Dukes, Flanagan, Mansour and Vajnovszki present Gray codes for several families of pattern avoiding permutations. In their Gray codes two consecutive objects differ in at most four or five positions, which is not optimal. In this paper, we present a unified construction in order to refine their results (or to find other Gray codes). In particular, we obtain more restrictive Gray codes for the two Wilf classes of Catalan permutations of length n; two consecutive objects differ in at most two or three positions which is optimal for n odd. Other refinements have been found for permutation sets enumerated by the numbers of Schröder, Pell, even index Fibonacci numbers and the central binomial coefficients. A general efficient generating algorithm is also given.     

Pseudo-Riemann-Stieltjes integral

An extension of the classical Riemann-Stieltjes integral to the field of pseudo-analysis is being investigated through this paper. Core of the construction presented here consists of generalized pseudo-operations given by monotone generating function.     

利用发电机组排气或余热进行供热及供冷的探讨

为合理使用能源,保护环境,介绍了利用发电机组排气或余热进行供热及制冷的5种方案.结合我国当前的的能源状况,分析了利用汽轮机、燃气轮机、内燃机等排气或余热进行热电联产及热电冷联产的适用情况及适用地区.     

排序算法与全排列生成算法研究

引入排序计算树和排列枚举树的概念,研究某些排序算法和全排列生成算法之间的关系,由插入排序算法直接导出了一个全排列生成算法,也由一个全排列生成算法导出了一个排序算法.     

THEORY OF HELICOID OF SPHERICAL HOB

ＴＨＥＯＲＹＯＦＨＥＬＩＣＯＩＤＯＦＳＰＨＥＲＩＣＡＬＨＯＢＴＨＥＯＲＹＯＦＨＥＬＩＣＯＩＤＯＦＳＰＨＥＲＩＣＡＬＨＯＢＣｕｉｙｕｎｑｉ；ＨｕＺｈａｎｑｉ（ＹａｎｓｈａｎＵｎｉｖｅｒｓｉｔｙ）ＡｂｓｔｒａｃｔＴｈｅｍｅｃｈａｎｉｓｍｏｆｓｐｈｅｒｉｃ...     

提高三峡机组运行可靠性的途径

2003年7月三峡机组顺利投产，极大地缓解了全国的“电荒”局面。然而，机组投产初期运行可靠性较低，强迫停运次数较多，给电力系统稳定运行造成了一定的影响。经分析，三峡主机运行稳定可靠，造成强迫停机的主要原因是机组辅助系统设计不合理、自动化元器件故障率高等。针对这一问题，三峡工程的运行和技术管理人员提出并实施了60余项反事故技改措施，优化、完善了机组保护和控制逻辑，有效地提高了机组运行可靠性。     

玫瑰线及其应用研究

根据基本玫瑰线方程,详细地分析了玫瑰线的参数特性及其对玫瑰线几何结构的影响,提出了玫瑰线的生成规则.只要简单选择n和θ参数,就可方便地生成所需的玫瑰线,并通过MATLAB编程,显示了各种形状的玫瑰线效果,并介绍了玫瑰线在图案设计中的应用.