基于滑动窗口的连续无线网络编码

根据无线单跳广播网络的特点,提出一种基于滑动窗口的网络编码方案——NCBSW,在待重传数据分组矩阵中设计一个按时间顺序滑动的编码窗口并在其中选择参与网络编码的分组,同时保证编码分组的可解性,从而减少数据分组的重传次数和传送时延。仿真分析结果表明：相对于NCWBR方案,NCBSW方案在数据分组的重传次数、传送时延和网络开销以及节点能耗等方面的性能更优。     

A method for parametrized contingency‐constrained optimal power flow (PCCOPF)

This paper presents a method for Parametrized Contingency Constrained Optimal Power Flow (PCCOPF) whose formulation can discriminate unpreventable contingencies, determine the existence of feasible solutions for postcontingencies, and analyze the feasible solution for the contingencies in terms of static sense. The proposed formulation is based on parametrized contingency constraints in which each contingency parameter represents the achievement ratio of each selected contingency. In the formulation, not only parametrized contingency constraints are given by a set of equality constraints which is modified power flow equations, but also the objective is maximization of the sum of the achievement ratios of selected contingencies. Since contingency parameters are treated as decision variables in the proposed method, the information on unsolvability with respect to each contingency can be efficiently obtained. The feasibility and effectiveness of the proposed method are demonstrated on test problems with 4‐bus and 71‐bus systems. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 21–31, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10182     

Strong solvability of interval max-plus systems and applications to optimal control

This paper considers the strong solvability of interval max-plus systems. The solvable entry and solvable interval are introduced to establish the necessary and sufficient condition for strong solvability of interval max-plus systems. It is proved that such a criterion is equivalent to the criterion proposed by Cechlárová and Cuninghame-Green. The interval strong solution of interval max-plus systems is described and the necessary and sufficient condition for uniquely strong solvability is given. The method of testing strong solvability of interval max-plus systems is constructive and leads to an effective algorithm. To illustrate our results, a workshop optimal control problem is addressed.     

On two linearized difference schemes for Burgers’ equation

Burgers’ equation can model several physical phenomena. In the first part of this work, we derive a three-level linearized difference scheme for Burgers’ equation, which is then proved to be energy conservative, unique solvable and unconditionally convergent in the maximum norm by the energy method combining with the inductive method. In the second part of the work, we prove the L_∞ unconditional convergence of a two-level linearized difference scheme for Burgers’ equation proposed by Sheng [A new difference scheme for Burgers equation, J. Jiangsu Normal Univ. 30 (2012), pp. 39–43], which was proved previously conditionally convergent.     

相场法模拟热耦合强度对纯Ni枝晶生长的影响

基于Karma的薄界面极限相场模型,研究了相场和温度场耦合强度对过冷纯Ni熔体中枝晶生长行为的影响。模拟结果表明:随着热耦合强度的减弱,相场受温度场的影响作用减弱,固-液相界面前沿扰动变大,主枝出现二次枝晶并逐渐发达粗化,其粗化方式由缩颈熔断向枝晶臂合并方式转变。同时,枝晶尖端的生长速率增大、曲率半径减小。瞬态过程中枝晶尖端生长速度大于稳态生长速度,随着生长过程的进行,枝晶尖端生长速度逐渐降低,直至达到稳态值,计算结果与微观可解理论吻合良好。     

关于Diophantine方程x~3-5~3=3py~2

设p是给定的素数,运用初等数论方法证明了方程x3-53=3py2有适合gcd(x,y)=1的正整数解(x,y)的充要条件是p=Q(27a4+45a2+25),其中a是正整数,Q(27a4+45a2+25)是27a4+45a2+25的无平方因子部分.由此可知,当p≠7或13(mod30)时,该方程没有适合gcd(x,y)=1的正整数解(x,y).     

Pre‐arrangement of solvability,complexity, stability and quality of GPC systems

A design problem of generalized predictive control (GPC) of plants characterized by discrete‐time models with a non‐zero transportation‐delay is considered. Conditions for the existence of the solution of the problem in terms of relevant design parameters (tuning knobs) are proposed and the system characteristics are discussed. Several design hints suitable for such plant models are proposed. Consequently, it is shown that by a suitable choice of the GPC tuning knobs a definite pre‐arrangement of the solvability, complexity, stability and quality (including robustness) of the resultant GPC control systems can be achieved. Some numerical examples are also given to illustrate the design problem and proposed methodology. Copyright © 2002 John Wiley & Sons, Ltd.     

基于最小不匹配函数的低压减载算法研究

为了恢复故障后潮流的可解性，提出了一个新的算法用来决定最小负荷减载问题。应用Damped Newton-Raphson法，以潮流方程的不匹配函数最小为优化目标，来识别弱节点，以确定最佳减载策略；将求解最小不匹配函数获得的最弱节点电压设为已知量，将负荷减载节点的负荷承载系数作为一个新的未知量，以计算修改后的最小不匹配函数，估计最小负荷减载量，并应用简单的P-V曲线法对估计结果进行修正，以提高计算精度。通过New-England 39节点系统和IEEE 30节点系统算例表明，此算法简单有效，易于实现。     

广义线性系统综述

系统地论述了广义线性系统的发展和研究现状,包括可解性、能控能观性、正则化、脉冲消除、观测器设计、故障检测.比较详细地对广义线性系统的特殊问题如能控能观性和脉冲消除等进行了阐述.讨论了目前研究中存在的问题及将来的研究方向.     

DSolving: a novel and efficient intelligent algorithm for large-scale sliding puzzles

Abstract

Sliding puzzles are classic and ancient intellectual problems. Since the amount of states in a sliding puzzle equals to the factorial of the number of tiles including the blank tile, traditional algorithms are only effective for small-scale ones, e.g. 8-puzzle. This article proposes a novel and efficient algorithm called DSolving for large-scale sliding puzzles. DSolving adopts direct solving manner. It does not need to store the intermediate states. Therefore, theoretically, it can solve any scale sliding puzzle. For general number tiles except the after-mentioned ones, DSolving adopts an efficient method to quickly move them to their target locations along shortest paths. For the top-right 3 × 2 corner sub-puzzles beginning with the last two positions in each row, DSolving constructs a state transition table (STT), which can ensure those two number tiles in the top-right corner be moved and placed correctly. The last two rows of tiles are considered as several 2 × 3 sub-puzzles, and another STT is constructed to solve these 2 × 3 sub-puzzles. These two STTs reduce corresponding problems to simple table-look-up operations. Experimental results show that DSolving exhibits high time-efficiency and stability. It takes only 4–5 ms to solve a random instance of 20 × 20 sliding puzzle on a general personal computer.