On one boundary problem for nonlinear stationary controlled system

The object of study is nonlinear stationary controlled system of ordinary differential equations with constant disturbance in the right part. The problem of constructing the synthesising control function providing the transfer of this system from the initial state to the origin is considered. The sufficiently simple for numerical implementation algorithm of solution of the above-mentioned problem is obtained. It is shown that for local null controllability of the considered system, it is sufficient that the conditions of the Kalman's type were satisfied. In addition, the estimates restricting the choice of initial conditions and external disturbances under which the transfer is guaranteed are obtained. The main idea of the method of construction of the desired control function consists in reducing the original problem to stabilisation of a special kind linear non-stationary system and solving the Cauchy problem for an auxiliary system of ordinary differential equations closed by stabilising control. The simplicity of the realisation of this algorithm is determined by the construction of the auxiliary system and its stabilisation that could be obtained by analytical methods. The effectiveness of the method is illustrated by solving the problem of crane control and its numerical simulation.     

四分之一波长间距阵抗拖船干扰研究

为改善拖曳线列阵声呐的尾向探测能力,降低拖船噪声对半波长间距阵尾向探测性能的制约,本文关注四分之一波长间距阵对连续波信号和带限噪声的响应。研究表明,四分之一波长间距阵具有非对称的端向指向性,与半波长间距阵相比有约20 d B的空间抑制能力,能有效抑制拖船辐射噪声干扰。本文还提出用零陷权组合传感器构成四分之一波长间距阵,理论上其抗拖船噪声干扰的效果比四分之一波长间距阵更好。     

Exploiting array manipulation habits to optimize garbage collection and type flow analysis

A widespread practice to implement a flexible array is to consider the storage area into two parts: the used area, which is already available for read/write operations, and the supply area, which is used in case of enlargement of the array. The main purpose of the supply area is to avoid as much as possible the reallocation of the whole storage area in case of enlargement. As the supply area is not used by the application, the main idea of the paper is to convey the information to the garbage collector, making it possible to avoid completely the marking of the supply area. We also present a simple method to analyze the types of objects, which are stored in an array as well as the possible presence of NULL values within the array. This allows us to better specialize the work of the garbage collector when marking the used area, and also, by transitivity, to improve overall results for type analysis of all expressions of the source code. After introducing several abstract data types, which represent the main arrays concerned by our technique (i.e., zero or variable indexing, circular arrays and hash maps), we measure its impact during the bootstrap of two compilers whose libraries are equipped with these abstract data types. We then measure, on various software products we have not written, the frequency of certain habits of manipulation of arrays, to assess the validity of our approach. Copyright © 2014 John Wiley & Sons, Ltd.     

What are the fundamental facts of a comparison of two treatments' outcomes?

Responds to comments by Stefan G. Hofmann (see record 2011-19228-003), Edward A. Wise (see record 2011-19228-004), Michael J. Lambert (see record 2011-19228-005), and William H. Gottdiener (see record 2011-19228-006) on the authors original article "Statistical significance testing and clinical trials" (see record 2011-19228-002). The original article is one very narrowly focused effort at studying the implications of relying on the null hypothesis significance test (NHST) for determining which psychotherapy randomized clinical trial (RCT) findings to take seriously for clinical purposes. Although there are several approaches for faulting the NHST, the matter is important and complicated enough to justify dealing, in detail, with one approach at a time. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

一种基于遗传算法的唯相位宽零陷波束赋形方法

传统阵列方向图宽零陷形成技术需要对阵元施加复加权或者阵元位置扰动等复杂操作,实际实现比较困难。提出了一种基于遗传算法的唯相位波束赋形方法,针对宽零陷特点,结合均匀线阵方向图数学模型,设计一种适应度函数,优化阵元相位扰动值,最终获得符合要求的宽零陷阵列方向图。仿真结果表明,该方法可以在唯相位条件下形成较深的宽零陷,且零陷较平坦,收敛速度较快,稳健性较好。     

一种秩基于降秩共轭梯度法的零陷加宽技术

在自适应阵列处理技术中,零陷加宽技术常用于增强自适应权和数据失配时的鲁棒性,但该技术同时会带来计算量的增加。将零陷加宽技术引入到降秩共轭梯度法中,提出了基于降秩共轭法的零陷加宽技术。相比于常规的零陷加宽技术,该方法有效地降低了计算量。计算机仿真表明,小快拍条件下新算法的干扰抑制性能优于常规零陷加宽法。     

Killeen's (2005) prep coefficient: Logical and mathematical problems.

In his article, “An alternative to null-hypothesis significance tests,” Killeen (2005) urged the discipline to abandon the practice of pobs-based null hypothesis testing and to quantify the signal-to-noise characteristics of experimental outcomes with replication probabilities. He described the coefficient that he invented, prep, as the probability of obtaining “an effect of the same sign as that found in an original experiment” (Killeen, 2005, p. 346). The journal Psychological Science quickly came to encourage researchers to employ prep, rather than pobs, in the reporting of their experimental findings. In the current article, we (a) establish that Killeen's derivation of prep contains an error, the result of which is that prep is not, in fact, the probability that Killeen set out to derive; (b) establish that prep is not a replication probability of any kind but, rather, is a quasi-power coefficient; and (c) suggest that Killeen has mischaracterized both the relationship between replication probabilities and statistical inference, and the kinds of claims that are licensed by knowledge of the value assumed by the replication probability that he attempted to derive. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Wide null control of symmetric linear antenna array using novel particle swarm optimization

In this article, the method of nullifying the radiation pattern of a symmetric linear antenna array in a particular direction is propounded using an evolutionary swarm intelligence technique, Novel particle swarm optimization (NPSO). Particle swarm optimization with constriction factor approach (PSOCFA) is also adopted to compare the NPSO based results. Single or multiple wide nulls are achieved by optimum perturbations of elements current amplitude weights to have symmetric nulls about the main beam. Different numerical examples are presented to illustrate the capability of NPSO for pattern synthesis with a prescribed wide nulls locations and depths. Further, the peak Sidelobe Levels are also reduces when compared to a uniformly excited array having equal number of elements. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

一种稳健的零陷扩展算法

协方差矩阵求逆算法具有在强干扰条件下提取弱期望的优良性能。但算法受幅相误差影响明显,且干扰方向处的零陷宽度很窄,当干扰方向变化时会导致抑制干扰能力下降。文章利用快速测向给出的信号示向度,运用最大似然迭代估计出各信源对应方向的实际方向向量值。再利用导数约束条件对协方差矩阵求逆算法的目标函数进行约束,从而使零陷宽度得以扩展且鲁棒性增强。仿真实验验证了算法的有效性。