Hyperbolic regression analysis for kinetics, electrophoresis, ELISA, RIA, Bradford, Lowry, and other applications

Hyperbolic regression analysis is an effective method for fitting experimental data points obtained from a variety of experiments in molecular biology, including enzyme kinetics, agarose gel electrophoresis of DNA fragments, SDS-polyacrylamide gel electrophoresis of proteins, enzyme-linked immunosorbent assays (ELISA), radioimmunoassays (RIA), Bradford protein quantitation assays, Lowry protein assays, and other applications. Hyperbolic regression yields excellent fitted curves without the biases that are introduced by carrying out linear regression on double reciprocal coordinates, and it produces one simple equation, encompassing all the data points, that can be used easily in a pocket calculator to estimate the values of unknown samples from the known standards.     

Pointcuts, advice, refinements, and collaborations: similarities, differences, and synergies

Aspect-oriented programming (AOP) is a novel programming paradigm that aims at modularizing complex software. It embraces several mechanisms including (1) pointcuts and advice as well as (2) refinements and collaborations. Though all these mechanisms deal with crosscutting concerns, i.e., a special class of design and implementation problems that challenge traditional programming paradigms, they do so in different ways. In this article we explore their relationship and their impact on modularity, which is an important prerequisite for reliable and maintainable software. Our exploration helps researchers and practitioners to understand their differences and exposes which mechanism is best used for which problem.     

Louis Kruh,Cryptologist, Editor,Activist

Abstract

The double transposition cipher was considered to be one of the most secure types of manual ciphers. It was extensively used in both World Wars and during the Cold War. In 1999, Otto Leiberich, the former head of the German federal office for information security, suggested that a double transposition challenge be published with specific parameters designed to ensure its security. Such a challenge was published by Klaus Schmeh in 2007. In November 2013, the authors solved the challenge using a ciphertext-only hill climbing attack. They also solved the challenge using a dictionary attack. In this article, they describe both methods, which are based on a “divide-and-conquer” approach. They additionally discuss the impact of their solutions with respect to the general security of the double transposition cipher.     

基于模糊PID参数自整定的细胞培养箱温度控制算法

针对细胞培养箱温度控制具有非线性、时滞性、易受干扰且难以建立精确的数学模型的特点,传统的PID控制方法对于快速维持系统箱内温度稳定存在一定的局限性。提出了以温度误差和误差变化率为控制输入,培养箱内温度为控制量的模糊PID参数自整定的温度控制算法,实现了对PID参数的实时在线修正。实验表明,该模糊PID参数自整定温度控制算法,温度从26℃上升到目标温度37℃,建立稳态的时间为2890s,温度超调极小。系统温度控制精度为±0.05℃,并在相同型号的细胞培养箱上同样得到验证。在控制稳定性方面获得了比传统PID控制更好的控温效果,稳定快,极小超调,温度控制精度高,能满足细胞培养箱温度控制的要求。     

Slope Intervals,Generalized Gradients,Semigradients, Slant Derivatives,and Csets

Many practical optimization problems are nonsmooth, and derivative-type methods cannot be applied. To overcome this difficulty, there are different concepts to replace the derivative of a function f : : interval slopes, semigradients, generalized gradients, and slant derivatives are some examples. These approaches generalize the success of convex analysis, and are effective in optimization. However, with the exception of interval slopes, it is not clear how to automatically compute these; having a general analogue to the chain rule, interval slopes can be computed with automatic differentiation techniques. In this paper we study the relationships among these approaches for nonsmooth Lipschitz optimization problems in finite dimensional Euclidean spaces. Inclusion theorems concerning the equivalence of these concepts when there exist one sided derivatives in one dimension and in multidimensional cases are proved separately. Valid enclosures are produced. Under containment set (cset) theory, for instance, the cset of the gradient of a locally Lipschitz function f near x is included in its generalized gradient.     

教学、创新、就业应行才至——更好、更积极、更深入地履行实践

现今,高校的实践活动越来越多,覆盖面越来越广,分类也越来越细。大学生刚入校有社会实践,到了大二、大三有专业实践,临近毕业还有就业实践。高校学生实践,正处于历史上发展最快的时期。如何更好、更快、更深入地发展实践,本期思维碰撞栏目将从教学改革方面谈起,为学生实践能力的培养寻找更有效的实践之道。     

Across disciplines: risk, design, method, process, and tools

In the search for solutions to make software development more predictable and controllable, one often looks for parallels in other disciplines such as architecture, bridge construction, and so on. The article looks at software development from the perspective of the electrical industry. Inspired by their management tradition, ATH techniek b.v. has learned to apply proven management techniques to software development. Simple and commonsense principles yield excellent results; for instance, developers reduced risk by estimating project effort using two different measures and by controlling execution. Comparing the software development processes with what goes on in the rest of the company or another application domain can be instructive     

Electronic Markets, Hierarchies, Hubs, and Intermediaries

The impact of information technologies on organizations is difficult to predict, although critical for developing comprehensive organizational strategies. Much of the difficulty is traceable to the treatment of all information technologies as a single factor, when in fact different technologies may have drastically different impacts on the organization. Specifically, the distinction between two general classes of technologies, communication and information processing technologies, is studied. An analytical model is developed to show that these two classes of technologies have exactly the opposite impacts on the organization. Moreover, the impact also depends on the organization, and its existing structure. Communication intensive and processing intensive organizational structures are distinguished and they are shown to be impacted differently by information technologies. An analytical framework is developed to show a continuum of organizational structures, depending on their relative communication and processing intensity, and the effect of various technologies is shown to be to move the organization along that continuum. Communication and information processing technologies are shown to move the organization in opposing directions. Finally, the analytical framework is shown to be robust and valid under a wide variety of conditions, covering most real life organizations.     

Phrenology, astrology, risk, and product quality

Engineering is the act of making intelligent tradeoffs and compromises among conflicting and sometimes mutually exclusive goals. To improve product performance, the die size might need to increase, which diminishes the chip's economic attractiveness. Assessing risk and product quality is not an exact science. Nevertheless, the computing industry's future rests as much on our success in achieving product quality as it does in continuing to innovate in circuits and microarchitectures     

Mandalas,screws, pears,and Klein bottles

The goal of this article is to present an informal introduction and tutorial on the production of aesthetically pleasing solid models. The article is intended for the nonmathematical reader interested in computer art. Simple generating formulas and recipes are included.