异步电路验证算法

异步电路因不受时钟偏差的限制而逐渐成为电路设计研究的热点 .发展自动化的验证工具已成为确保大规模异步电路质量和性能的关键 .其核心课题就是建立异步电路的验证算法 .该文整理列举了基于多种数学模型的验证算法 ,如逻辑模型、代数模型、符号模型、数值模型和几何模型的验证算法 ,并从应用的角度将现有的异步电路验证算法分为两类 ,分别是事件时序分析类算法和状态空间搜索类算法 ,从算法的理论基础、应用背景、模型结构、图形描述、适用范围、算法复杂度编程复杂度等多个角度作了比较研究 ,给出了部分代表算法的应用算例 ,最后总结了在实际问题中选择验证算法的原则     

Micropneumatic Digital Logic Structures for Integrated Microdevice Computation and Control

It is shown that microfabricated polydimethylsiloxane membrane valve structures can be configured to function as transistors in pneumatic digital logic circuits. Using the analogy with metal-oxide-semiconductor field-effect transistor circuits, networks of pneumatically actuated microvalves are designed to produce pneumatic digital logic gates (AND, OR, NOT, NAND, and XOR). These logic gates are combined to form 4- and 8-bit ripple-carry adders as a demonstration of their universal pneumatic computing capabilities. Signal propagation through these pneumatic circuits is characterized, and an amplifier circuit is demonstrated for improved signal transduction. Propagation of pneumatic carry information through the 8-bit adder is complete within 1.1 s, demonstrating the feasibility of integrated temporal control of pneumatic actuation systems. Integrated pneumatic logical systems reduce the number of off-chip controllers required for lab-on-a-chip and microelectromechanical system devices, allowing greater complexity and portability. This technology also enables the development of digital pneumatic computing and logic systems that are immune to electromagnetic interference.     

Microfluidic integrated circuits for signal processing using analogous relationship between pneumatic microvalve and MOSFET

In this paper, a new concept and potential demonstration of functional microfluidic integrated circuits using MEMS technology are presented. The fluidic integrated circuits were constructed utilizing analogous relationship between MOSFET and pneumatic microvalve with a diaphragm structure. The signal transmitted through the circuit is the fluidic signal, that is, the pressure or the flow-rate of the fluid. The pneumatic microvalve in this study is expressed by small-signal equivalent model similar to that of a MOSFET. Small signal behavior of microfluidic integrated circuits can be expected using the model, if the parameters in the model are extracted properly from fabricated microvalves. As an example of a fluidic circuit, pressure inverting amplifiers including integrated two microvalves were fabricated and evaluated. As a result, they showed sharp pressure transfer curves similar to MOS inverter circuits. A maximum pressure gain of 32.0 dB was obtained, and it can be used for pressure amplification in analog applications. In addition, they can be used as pressure inverter logic circuits for digital applications. Although the theory and design environment of the new microvalve circuit technology have not been established yet, multifunctional fluidic analog and digital circuits can be realized for special application fields different from electronic integrated circuits.     

A web-based computer-aided pneumatic circuit design software

A web-based collaborative pneumatic software is created to assist users on the computer-aided pneumatic circuit design. The software is developed in the form of Java application and Java applet. Therefore, it can be used in any computer with Java virtual machine or be accessed by a web browser over the internet.This software allows user to conduct pneumatic circuit design by (1) applying the circuit components on menu bar to draw the pneumatic devices, (2) connecting the devices with signal lines, (3) filling in the parameters for all the devices and finally, (4) simulating the designed circuit. To provide better simulation results for each device, separate threads are used to perform continuous scans to each component. Therefore, the actions of the pneumatic devices and circuits can be simulated throughout the design phases. The circuit design results can be saved either on each local disk for Java application users or on web-based databases for collaborative users.During a collaborative mode, the user who owns the token will dominate the circuit design process while the other users can only monitor the consequences. The token can be passed around the users on a collaborative scheme.Since the software is designed in Java, all pneumatic devices were designed as component based objects to allow user defined devices to be incorporated into the software in a systematic way.     

Simplified symbolic transfer function factorization using combined artificial bee colony and simulated annealing

Symbolic circuit analysis inherits the exponential growth of transfer function complexity with the circuit size. Therefore, symbolic simplification is an NP-hard problem. Although many simplification techniques have been presented, the simplified transfer functions are not written in a factorized form, and consequently, it is difficult to assess the contribution of poles and zeros on the circuit behavior. In this paper, a swarm intelligence based methodology is presented for the simplified factorized symbolic analysis of analog circuits. In this method, an extension of the root splitting technique is utilized to rewrite the expanded transfer function of the circuit into a factorized form comprising DC-gain, poles, and zeros. Then, the derived factorized transfer function is simplified using a hybrid Global and Local search algorithm based on Artificial Bee Colony and Simulated Annealing (named GLABCSA). The objective function is defined to minimize the complexity of the symbolic factorized transfer function while minimizing the DC-gain error and pole/zero displacements. The presented approach has been successfully developed in MATLAB. The program can derive the simplified factorized symbolic transfer function automatically from the input text netlist of the circuit. Symbolic and numerical results over two analog amplifiers are given to illustrate the efficiency of the presented methodology.     

Modeling selective attention using a neuromorphic analog VLSI device

Attentional mechanisms are required to overcome the problem of flooding a limited processing capacity system with information. They are present in biological sensory systems and can be a useful engineering tool for artificial visual systems. In this article we present a hardware model of a selective attention mechanism implemented on a very large-scale integration (VLSI) chip, using analog neuromorphic circuits. The chip exploits a spike-based representation to receive, process, and transmit signals. It can be used as a transceiver module for building multichip neuromorphic vision systems. We describe the circuits that carry out the main processing stages of the selective attention mechanism and provide experimental data for each circuit. We demonstrate the expected behavior of the model at the system level by stimulating the chip with both artificially generated control signals and signals obtained from a saliency map, computed from an image containing several salient features.     

Symbolic manipulation CAD of control engineering by using REDUCE

Computer aided design (CAD) is an indispensable tool for control engineering. Recently various CAD systems have been developed by using numerical computation languages, but these are not capable of treating symbolic computation. However, control theories provide many symbolic computation algorithms. This study develops a new CAD system which can perform symbolic manipulation, based on REDUCE 3.2. It is shown that this CAD system can be applied to wider problems than the conventional ones, by means of two examples.     

Linear nearest neighbor optimization in quantum circuits: a multiobjective perspective

Several current implementations of quantum circuits rely on the linear nearest neighbor restriction, which only allows interaction between adjacent qubits. Most methods that address the process of converting a generic circuit to an equivalent circuit which satisfies this restriction, minimize the number of additional SWAP gates required by this process. Moreover, most methods which address this problem are designed for 1D circuits. Considering the new and promising proposals for 2D quantum circuits, what we propose is a new perspective on this problem, namely that it can be seen as a multiobjective optimization problem. To test our hypothesis, we developed a multiobjective evolutionary algorithm that solves this problem by considering two objectives: minimizing the size of the 2D grid where the circuit is placed, and minimizing the number of additional SWAP gates. Of the methods designed for 2D circuits, only one considers different grid sizes which are much larger than strictly necessary. Consequently, our algorithm makes considerations which other methods do not make, since it naturally finds the grid which requires fewer SWAP gates for the circuit conversion, whether it is one-dimensional or two-dimensional. Our experimental results indicate that allowing a larger grid size results in fewer additional SWAP gates in about 73% of the tested circuits. Additionally, the average improvement we found when using larger grid sizes is about 30%, while the best improvement over using the smallest possible grid is 63.8%.     

General decomposition of incompletely specified sequential machines with multi-state behavior realization

This paper is devoted to decomposition of sequential machines, discrete functions and relations. Sequential machine decomposition consists in representation of a given machine as a network of collaborating partial machines that together realize behavior of the given machine. A good understanding of possible decomposition structures and of conditions under which the corresponding structures exist is a prerequisite for any adequate circuit or system synthesis. The paper discusses the theory of general decomposition of incompletely specified sequential machines with multi-state behavior realization. The central point of this theory is a constructive theorem on the existence of the general decomposition structures and conditions under which the corresponding structures exist. The theory of general decomposition presented in this paper is the most general known theory of the binary, multi-valued and symbolic sequential and combinational discrete network structures. The correct circuit generator defined by the general decomposition theorem covers all other known structural models of sequential and combinational circuits as its special cases. Using this theory, in recent years we developed a number of effective and efficient methods and EDA tools for sequential and combinational circuit synthesis that consistently construct much better circuits than other academic and commercial state-of-the-art synthesis tools. This demonstrates the practical soundness of our theory. This theory can be applied to any sort of binary, multi-valued and symbolic systems expressed as networks of relations, functions or sequential machines, and can be very useful in such fields as circuit and architecture synthesis of VLSI systems, knowledge engineering, machine learning, neural network training, pattern analysis, etc.     

Dynamically changing the logical behavior of the microcomputerinterface

Industrial programmable controllers and hardware simulators currently use the software method of direct logic simulation. In this method, programs contain the logical functions of several Boolean variables that are encoded directly. Each combinational circuit expressed by a group of Boolean equations requires an independent program. An alternative solution for the software implementation of the Boolean equations, named the product terms method, is presented. This method features the use of a single program to implement any multiple-output combinational circuit. To make the distinction between different circuits, a block of data defines each circuit. The product method is extended to synchronous sequential circuits, for which two tables are used. One table determines the next state of the combinational circuit, and the second table determines the outputs. An expert system has been developed to generate the table used in the product terms by interpreting the symbolic Boolean equations supplied by the user. The implementation and testing of the method are described     

Symbolic Feedback Control for Navigation

We discuss the generation of symbolic feedback control sequences for navigating a sparsely-described and uncertain environment, together with the problem of sensing landmarks sufficiently well to make feedback meaningful. We explore the use of a symbolic control approach for mitigating the lack of a detailed map of the environment and for reducing the complexity associated with finding control laws which steer a control system between distant locations. Under our language-based approach, control inputs take the form of symbolic strings. The decision process that generates those strings is guided by estimates of the vehicle's location within a set of important landmarks and by the statistical effectiveness of each string. This arrangement, and in particular the symbolic nature of the control set, allows us to formulate and solve a class of optimal navigation problems which would be exceedingly difficult to handle if approached at the level of sensors and actuators. Our approach is illustrated in a series of numerical indoor navigation experiments.     

单片机80C51在变电站自动减载控制系统中的应用研究

由于拉闸限电,使用电单位内一些较重要部门的供电也不能得到保障。本系统即使用单片微处理器80C51设计一个应用于10Kv/0.4Kv系统的自动减载装置。此装置能在变电站用电总负荷超标时自动断开一条或多条非重要负荷的供电线路,使本站的用电总负荷被限制在一个给定的容量范围之内。这样可以使上一级变电站不至于因用电紧张而拉闸。     

A unified symbolic evaluation framework for parallelizing compilers

The quality of many optimizations and analyses of parallelizing compilers depends significantly on the ability to evaluate symbolic expressions and on the amount of information available about program variables at arbitrary program points. In this paper, we describe an effective and unified symbolic evaluation framework that statically determines the values of variables and symbolic expressions, assumptions about and constraints between variable values, and the condition under which control flow reaches a program statement. We introduce the program context, a novel representation for comprehensive and compact control and data flow analysis information. Program contexts are described as first order logic formulas, which allows us to use public domain software for standard symbolic manipulation. Computations are represented as algebraic expressions defined over a program's problem size. Our symbolic evaluation techniques comprise accurate modeling of assignment and input/output statements, branches, loops, recurrences, arrays, and procedures. All of our techniques target both linear, as well as nonlinear, expressions and constraints. Efficiency of symbolic evaluation is highly improved by aggressive simplification techniques. A variety of examples, including program verification, dependence analysis, array privatization, communication vectorization, and elimination of redundant communication, are used to illustrate the effectiveness of our approach. We present results from a preliminary implementation of our framework, which is used as part of a parallelizing compiler that demonstrates the potential performance gains achievable by employing symbolic evaluation to support program parallelization.     

热力学数据库符号运算系统研究与实现

为了解决热力学数据库符号运算问题,本文分析Matlab混合编程方法,构建基于Matlab引擎和Web Service的热力学数据库符号运算系统,简化热力学数据库实现符号运算的过程,同时也实现异构热力学数据库与热力学数据库符号运算系统的集成。     

Emitter-couple logic circuit design based on the threshold-arithmetic algebraic system

Based on the threshold-arithmetic algebraic system which has been proposed for current-mode circuit design,we propose a systematic methodology for emitter-couple logic(ECL)circuit design.Compared to the traditional methodologies and the theory of differential current switches,the proposed methodology uses the HE map and the characteristics of the internal current signals of ECL circuits to determine the external voltage signals.The operations of the HE map are direct and simple,and the current signals are easy to add or subtract,which make this methodology more flexible,direct,and effective,and make it possible to design arbitrary binary and multi-valued logic functions.Two example circuits are designed and simulated by HSPICE using 0.18μm TSMC technology.Simulation results confirm the validity of the proposed methodology.     

A Fully-Automated Electron Beam Test System for VLSI Circuits

A fully automated, stroboscopic electrobeam test system that analyzes the behavior of logic VLSI circuits, this system consists of a stroboscopic electron-beam tester combined with an LSI CAD system. LSI circuit design data, read from the CAD system, provides a designed map. The host computer performs interconnection pattern recognition by superimposing this map onto an observed stroboscopic SEM image. Then, once the circuit nodes for voltage waveform measurements are automatically determined on the superimposed map. Next, the electron beam is positioned on the actual circuit-under-test wires. These automatic processes result in measured waveforms, which are displayed on the host computer terminal. This system has been applied to a 2.3K-gate logic LSI circuits, and has been successful in locating the critical path. This system, coupled with the recently developed fault diagnostic electron-beam tester, Finder, constitutes a unified electron-beam test system.     

符号模拟

符号模拟将模拟验证从布尔值扩展到符号领域，是集成电路验证行业中的重要分支。符号方法将符号值加到待验证电路的基本输入端，依次计算每个结点的布尔函数，直到在电路的输出端得到由这些初始符号变量组成的布尔表达式，并判断其是否具有所期望的特征。该文介绍了符号模拟的发展过程、基本技术及其所面临的BDD爆炸问题，并对消除该问题的两种技术：近似值法和参数方法，进行了讨论。介绍了具有一定自动机处理能力的符号轨迹评价方法。     

Dynamic routing and admission control for virtual circuit networks

The dynamic joint routing and admission control problem in multiple class multiple source-destination virtual circuit networks is considered. A nonlinear dynamic queueing model for virtual circuit networks that considers the dynamic interaction among the virtual circuit and packet processes is introduced. Then a multi-objective cost function of rejecting and maintaining virtual circuits, as well as of delaying and servicing packets is defined. The combined problem is formulated as an optimal control problem. Necessary optimality conditions are provided by Pontryagin's maximum principle. Sufficient optimality conditions based on the convexity of the Hamiltonian function are also given. For the finite horizon, the optimal controls can be found after numerically solving a Two-Point Boundary-Value Problem. For the longrun stationary equilibrium, the state-dependent routing and admission controls are derived.This work was supported by the National Science Foundation under Grant DMC-8452002 together with matching funds from AT&T Information Systems.     

基于混沌电路的模拟式阵列触觉传感器A öD 转换电路

本文利用混沌帐篷映射电路对小信号敏感及非线性变换的独特性能 ,提出了一种新颖的适用于模拟式阵列触觉传感器的 A / D转换电路 ,具有调理放大和 A/ D转换功能一体化优点 ,并且电路简单、易于集成实现 ,可实现多路触觉信号的同时采样和 A / D转换