Algorithmic synthesis of a combinational adder of decimal digits encoded by the Johnson-Mobius code

Methods are considered of construction of a combinational adder of decimal digits encoded by the Johnson-Mobius code. An algorithmic method of decimal adder synthesis is proposed. An implementation of such an adder using quantum-dot cellular automata is described. The successful computer simulation of an adder is executed. An evaluation is given of the construction and time parameters in comparison with a traditional binary-decimal four-bit adder.     

高速数字系统中信号完整性和传输延时分析

在高速数字系统设计中，信号完整性(SI)问题以及互连延迟引起的时序问题至关重要。详细分析推导了高速数字系统中各信号的信号完整性和传输延时约束关系，通过一个实例，给出了如何应用约束条件的具体方法。     

数字通道传输延迟时间测量方法研究

在集成电路测试领域,传输延迟时间tPD是一个非常重要的参数,其不仅反映集成电路对信号的响应速度,也是集成电路测试系统交流参数测量准确的重要影响因素。详细分析了集成电路测试系统传输延迟时间产生的原因,及其对待测器件交流参数测量结果的影响。提出了基于时域反射技术的集成电路测试系统数字通道传输延迟测量方法,并在泰瑞达J750EX集成电路测试系统上进行了实验验证。通过对实验数据的分析,表明该方法能有效测量数字通道传输延迟时间,提高集成电路测试系统交流参数测量准确度。     

基于FPGA的B码同步信号源的设计

Cyclone是Altera公司推出的低价格、高容量的FPGA,具有多达20 060个逻辑单元和173个可使用的I/O管脚.IRIG-B码是标准时间码格式之一,广泛应用于靶场时间信息的传递和各系统的信号同步.利用FPGA和高精度频率源设计的同步信号源,将同步信号精度由原来的200 ns提高到10 ns,并实现了系统的小型化、模块化.结果表明,该系统运行稳定,调试方便,具有较强的抗干扰能力和实际应用价值.     

On the principle of reduction for the nonlinear delay systems

Results were presented enabling one to reduce the problem equilibrium stability for multidimensional delay systems to a similar problem for more than one system of lower dimensionality. The results were established using fixed-sign (degenerate) Lyapunov functions and the limiting systems. The latter were constructed under more general assumptions about the right-hand side of the system than those used traditionally.     

Application of static analyses for state-space reduction to the microcontroller binary code

This paper describes the application of two abstraction techniques, namely dead variable reduction and path reduction, to the microcontroller binary code in order to tackle the state-explosion problem in model checking. These abstraction techniques are based on static analyses, which have to cope with the peculiarities of the binary code such as hardware dependencies, interrupts, recursion, and globally accessible memory locations. An interprocedural static analysis framework is presented that handles these peculiarities. Based on this framework, extensions of dead variable reduction and path reduction are detailed. A case study using several microcontroller programs is presented in order to demonstrate the efficiency of the described abstraction techniques.     

基于LabVIEW的UWT语音信号降噪处理

在LabVIEW软件平台下,应用UWT(非降采样小波变换)算法设计一新型处理软件,该软件集合了db5、coif5、sym5等三种不同正交小波的信号分解、阈值去噪和信号重构算法,并使用该软件成功地还原了一带噪语音信号,得出在强噪声背景下,该小波变换算法具有良好的保留语音原信号特性且降噪效果优越的结论。     

The politics of the code

This article explores the software behind the interface of the programs we use in composition classrooms—the principles of Structured Programming (SP), file structure, and some other significant issues in programming—and places the production of software in a cultural context. Programming protocol is shaped by two major strands: the profit imperative and the hierarchical structure of corporate America. The assumptions and procedures of Structured Programming are critiqued, and hypertext, structured programming, and natural-language writing are compared. This article suggests that writing instructors think about ways to customize programs used in their composition classes and to understand the implications and limitations of the necromancy of software.     

QR code based color image cryptography for the secured transmission of ECG signal

Multimedia Tools and Applications - The paper presents a novel QR code based color image steganography to facilitate remote transmission of ECG signal along with patient diagnosis data. The...     

Chattering reduction of sliding mode control by low‐pass filtering the control signal

The conventional approach to reducing control signal chattering in sliding mode control is to use the boundary layer design. However, when there is high‐level measurement noise, the boundary layer design becomes ineffective in chattering reduction. This paper, therefore, proposes a new design for chattering reduction by low‐pass filtering the control signal. The new design is non‐trivial since it requires estimation of the sliding variable via a disturbance estimator. The new sliding mode control has the same performance as the boundary layer design in noise‐free environments, and outperforms the boundary layer design in noisy environments. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

室内非视距环境超宽带信号传播特性研究

基于时域射线跟踪方法对室内超宽带信号传播进行了仿真和分析。设计了一种应用于室内带金属家具非视距环境的超宽带信号信道仿真模型,用以分析和描述超宽带信号经室内反射、透射和绕射传播后的时域电场强度,同时比较分析了仿真得到的视距传播和非视距传播中的多径传播、功率时延分布等传播参数。仿真结果可以为室内复杂环境中超宽带无线通信网络覆盖与优化提供理论依据。     

A comparative study on the intensity and harmfulness of late propagation in near-miss code clones

Exact or nearly similar code fragments in a software system’s source code are referred to as code clones. It is often the case that updates (i.e., changes) to a code clone will need to be propagated to its related code clones to preserve their similarity and to maintain source code consistency. When there is a delay in propagating the changes (possibly because the developer is unaware of the related cloned code), the system might behave incorrectly. A delay in propagating a change is referred to as ‘late propagation,’ and a number of studies have investigated this phenomenon. However, these studies did not investigate the intensity of late propagation nor how late propagation differs by clone type. In this research, we investigate late propagation separately for each of the three clone types (Type 1, Type 2, and Type 3). According to our experimental results on thousands of revisions of eight diverse subject systems written in two programming languages, late propagation occurs more frequently in Type 3 clones compared with the other two clone types. More importantly, there is a higher probability that Type 3 clones will experience buggy late propagations compared with the other two clone types. Also, we discovered that block clones are more involved in late propagation than method clones. Refactoring and tracking of Similarity Preserving Change Pattern (SPCP) clones (i.e., the clone fragments that evolve following a SPCP) can help us minimize the occurrences of late propagation in clones.     

The dynamic stresses induced by the propagation of skew cracks

Skew crack propagation in an elastic medium due to the application of transient in-plane and anti-plane loads is investigated. For the anti-plane loading the motion of the crack is purely of mode III type, whereas in the case of in-plane loading a mixed mode type of fracture takes place in which both modes I and II occur. The method of solution is numerical and is based on a certain time-dependent transformation which maps the physical plane of the crack into an auxiliary plane in which the crack propagates collinearly with its propagating tip appearing always at the origin of the moving coordinate system. The transformed equations of motion are approximated by an implicit, three-level, finite difference system of equations of second-order accuracy, whose stability analysis is discussed. The reliability of the proposed method of solution is examined in several situations in which analytical results are known, and satisfactory agreement is achieved. Extension to smoothly curving cracks is discussed.     

室内有金属家具环境超宽带信号传播特性研究

超宽带信号传播特性是超宽带信道理论的重要组成部分。基于时域射线跟踪方法对有金属家具的室内复杂环境中超宽带信号传播特性进行了研究,全面考虑了包括直射、反射、绕射和透射的多径传播机制,仿真获得了接收功率、均方根时延扩展等传播特性。仿真结果表明:(1)金属家具的存在使得接收功率和均方根时延扩展普遍降低;(2)在非视距传播中高次反射与绕射的作用明显,不可忽略。仿真结果可以为室内复杂环境中超宽带无线通信网络覆盖与优化提供理论依据。     

基于AT89S51单片机的PWM专用信号发生器的设计

介绍一种脉冲涡流无损检测系统所使用的多波形专用PWM信号发生器的设计。该信号发生器以单片机为核心控制单元,通过对外围芯片的控制来实现对输出波形的频率、电压幅值、占空比的连续调节,并能对运行信号参数进行实时显示。经实验验证,该信号发生器便于观察和调节,完全满足脉冲涡流检测系统所需激励信号的要求。     

基于AT89S51单片机的PWM专用信号发生器的设计

介绍一种脉冲涡流无损检测系统所使用的多波形专用PWM信号发生器的设计.该信号发生器以单片机为核心控制单元,通过对外围芯片的控制来实现对输出波形的频率、电压幅值、占空比的连续调节,并能对运行信号参数进行实时显示.经实验验证,该信号发生器便于观察和调节,完全满足脉冲涡流检测系统所需激励信号的要求.     

Genetic code optimality studied by means of simulated evolution and within the coevolution theory of the canonical code organization

We have studied the canonical genetic code optimality by means of simulated evolution. A genetic algorithm is used to search for better adapted hypothetical codes and as a method to guess the difficulty in finding such alternative codes. Such analysis is performed within the coevolution theory of the genetic code organization. We have studied the progression of the canonical genetic code optimality within such theory, considering a possible scenario of a previous code with two-letter codons as well as the current organization of the canonical code. Moreover, we have analysed the particular optimality and progression of adaptability of the individual nucleotide bases.     

A theoretical model of axon guidance by the Robo code

After crossing the midline, different populations of commissural axons in Drosophila target specific longitudinal pathways at different distances from the midline. It has recently been shown that this choice of lateral position is governed by the particular combination of Robo receptors expressed by these axons, presumably in response to a gradient of Slit released by the midline. Here we propose a simple theoretical model of this combinatorial coding scheme. The principal results of the model are that purely quantitative rather than qualitative differences between the different Robo receptors are sufficient to account for the effects observed following removal or ectopic expression of specific Robo receptors, and that the steepness of the Slit gradient in vivo must exceed a certain minimum for the results observed experimentally to be consistent.     

Power reduction of micro‐electro‐mechanical system shutter display by temporal smoothing of image signal

Power reduction technique for micro‐electro‐mechanical system (MEMS) shutter display employing a time‐division pulse‐width‐modulation gray scale expression method has been proposed. By temporally smoothing the column data signal, transition frequency between open and closed states of the MEMS shutter decreases, resulting in power reduction. In order to suppress color distortion due to the smoothing, the number of smoothing subfield is limited. In addition, the number of smoothing subfield is adjusted for each pixel after calculating color difference between the original and smoothed pixels. Simulated experiments show about 20% reduction of the transition number of MEMS shutter state when the color‐difference tolerance is 0.8 and the maximum number of smoothing subfield is 3.