基于自适应免疫进化算法的逻辑电路设计*

针对现有进化算法在进行逻辑电路设计时存在的进化缓慢和容易陷入局部解等问题,提出一种自适应免疫进化算法（adaptive immune evolutionary algorithm,AIEA）。该算法引入了免疫记忆机制和抗体差异调节算子,能够很好地保证个体的多样性,有利于跳出局部最优解;通过采用自适应交叉率和变异率,提高了算法的搜索能力和收敛速度。通过与多目标进化算法（MOEA）、简单免疫算法（SIA）的实验比较,证明了该自适应免疫进化算法的有效性。     

A new mutation operator for evolutionary airfoil design

A new mutation operator, ℳ _ijn , capable of operating on a set of adjacent bits in one single step, is introduced. Its features are examined and compared against those of the classical bit–flip mutation. A simple Evolutionary Algorithm, ℳ–EA, based only on selection and ℳ _ijn , is described. This algorithm is used for the solution of an industrial problem, the Inverse Airfoil Design optimization, characterized by high search time to achieve satisfying solutions, and its performance is compared against that offered by a classical binary Genetic Algorithm. The experiments show for our algorithm a noticeable reduction in the time needed to reach a solution of acceptable quality, thus they prove the effectiveness of the proposed operator and its superiority to GAs for the problem at hand.     

On the use of energy minimization for CA based analysis in elasticity

There has been recent interest in exploring alternative computational models for structural analysis that are better suited for a design environment requiring repetitive analysis. The need for such models is brought about by significant increases in computer processing speeds, realized primarily through parallel processing. To take full advantage of such parallel machines, however, the computational approach itself must be revisited from a totally different perspective; parallelization of inherently serial paradigms is subject to limitations introduced by a requirement of information coordination. The cellular automata (CA) model of decentralized computations provides one such approach which is ideally tailored for parallel computers. The proposed paper examines the applicability of the cellular automata model in problems of 2-D elasticity. The focus of the paper is in the use of a genetic algorithm based optimization process to derive the rules for local interaction required in evolving the cellular automata. Received August 28, 2000     

Damage-reduction-based structural optimum design for seismic RC frames

The development of structural seismic design is briefly reviewed with an emphasis on different conceptual approaches and their success in practical engineering applications. The concept of damage-reduction-based seismic design is proposed, in which the whole structural system is either physically or functionally designed as two parts, the main-function part and the damage-reduction part. The main-function part satisfies the serviceability requirements of the structural system. The damage-reduction part is composed of several damage-reduction elements, which work under hazard loads to ensure the safety of the main-function part, and further maintain the serviceability of the structural system by specific damage-reduction techniques or even by failure of damage-reduction elements. The formulation of damage-reduction-based optimum design for seismic structures is presented and some related issues are addressed, including a simplified approach to reliability analysis, the evaluation of the structural loss expectation, and the modified enumeration method. Numerical examples of RC frames are examined. The results show that several measures of structural seismic performance, including the life-cycle cost, severe earthquake action, and the story-drift reliability index of the weakest story, can be improved by damage-reduction-based design compared with conventional design.     

基于指标结构基因模型的评价驱动型产品设计

针对产品方案设计中用户反馈信息处理、转化问题,提出了交互式产品设计方法,建立了以用户交互式评价为核心的"指标-结构-基因"产品设计模型。该模型应用模糊集与粗糙集理论处理用户评价信息;利用灰色系统理论,应用层次分析法建立评价指标体系,实现由指标体系到产品结构的转换;采用遗传算法,通过产品结构基因编码,根据用户交互式评价,获得产品进化设计方案。以某企业婴儿手推车产品方案设计为例,阐述了应用该方法进行产品方案设计的一般步骤。     

A mutual energy formulation for optimal structural design

This paper presents a variational formulation for the design of elastic structures where the function to be minimized by the optimal design, i.e. the objective, is expressed in abstract form. The resulting statement of necessary conditions is uniformly applicable for all admissible objectives. Both state and adjoint state variables appear directly in the problem statement, and all objectives and the arguments of constraints are scalars. The adjoint pair of state variables appear in symmetric roles via the expression termed “mutual energy". Application of the generalized formulation is demonstrated by treatment of the following examples: design to minimize the maximum value of displacement or to minimize a global measure of stress, design for generalized compliance, design where self-weight is taken into account, and multicriterion design. Received April 28, 2000     

一种基于演化计算的在线手写签名验证算法实现

提出了基于演化计算的在线手写签名验证算法。该算法将参考签名分割成曲线段,以一定长度的搜索窗在测试签名曲线上进行动态搜索,实现与参考签名曲线段自适应的动态分割与匹配。在算法中引进了演化计算中的分级和加速技术,使算法的搜索速度和匹配效果有了一定程度的提高。实验结果表明了该算法的有效性。     

基于均匀设计的中心引力优化算法

中心引力优化（Central Force Optimization,CFO）算法是一种新型多维搜索确定型启发式优化算法,但由于它的初始探测器（Probe）计算复杂而导致CFO算法运行时间过长。针对初始探测器计算复杂问题,提出一种均匀设计方法,依此方法提出了基于均匀设计的CFO算法。将提出的CFO算法应用到典型测试函数中,并与CFO算法进行比较。数值结果表明,该算法保证寻优能力同时减少了CFO算法的运行时间,从而提高了CFO算法的效率。     

A new dynamical evolutionary algorithm based on statistical mechanics

In this paper,a new dynamical evolutionary algorithm(DEA) is presented based on the theory of statistical mechanics.The novelty of this kind of dynamical evolutionary algorithm is that all individuals in a population(called particles in a dynamical system)are running and searching with their population evolving driven by a new selecting mechanism.This mechanism simulates the principle of molecular dynamics,which is easy to design and implement.A basic theoretical analysis for the dynamical evolutionary algorithm is given and as a consequence two stopping criteria of the algorithm are derived from the principle of energy minimization and the law of entropy increasing.In order to verify the effectiveness of the scheme,DEA is applied to sloving some typical numerical function minimization problems which are poorly solved by traditional evolutionary algorithms.The experimental results show that EAT is fast and reliable.     

Integration of topology and shape optimization for design of structural components

This paper presents an integrated approach that supports the topology optimization and CAD-based shape optimization. The main contribution of the paper is using the geometric reconstruction technique that is mathematically sound and error bounded for creating solid models of the topologically optimized structures with smooth geometric boundary. This geometric reconstruction method extends the integration to 3-D applications. In addition, commercial Computer-Aided Design (CAD), finite element analysis (FEA), optimization, and application software tools are incorporated to support the integrated optimization process. The integration is carried out by first converting the geometry of the topologically optimized structure into smooth and parametric B-spline curves and surfaces. The B-spline curves and surfaces are then imported into a parametric CAD environment to build solid models of the structure. The control point movements of the B-spline curves or surfaces are defined as design variables for shape optimization, in which CAD-based design velocity field computations, design sensitivity analysis (DSA), and nonlinear programming are performed. Both 2-D plane stress and 3-D solid examples are presented to demonstrate the proposed approach. Received January 27, 2000 Communicated by J. Sobieski     

A new look at ESO and BESO optimization methods

The “hard-kill” optimization methods such as evolutionary structural optimization (ESO) and bidirectional evolutionary structural optimization (BESO) may result in a nonoptimal design (Zhou and Rozvany in Struct Multidisc Optim 21:80–83, 2001) when these methods are implemented and used inadequately. This note further examines this important problem and shows that failure of ESO may occur when a prescribed boundary support is broken for a statically indeterminate structure. When a boundary support is broken, the structural system could be completely changed from the one originally defined in the initial design and even BESO would not be able to rectify the nonoptimal design. To avoid this problem, it is imperative that the prescribed boundary conditions for the structure be checked and maintained at each iteration during the optimization process. Several simple procedures for solving this problem are suggested. The benchmark problem proposed by Zhou and Rozvany (Struct Multidisc Optim 21:80–83, 2001) is revisited, and it is shown that the highly nonoptimal design can be easily avoided.     

Study of a new local update scheme for cellular automata in structural design

This paper investigates an improved local update scheme for cellular automata (CA) applied to structural design. Local analysis and design rules are derived for equilibrium and minimum compliance design. The new update scheme consists of repeating analysis and optimality-based design rules locally. The benefits of this approach are demonstrated through a series of systematic experiments. Truss topology design problems of various sizes are used based on the Gauss–Seidel and the Jacobi iteration modes. Experiments show the robust convergence of the approach as compared to an earlier CA implementation. The approach is also extended to a plate problem.     

基于多目标进化算法的WCDMA功率优化配置研究

在注重导频功率配置的基础上,研究了用户业务功率、同步信道功率和寻呼信道功率的配置,建立了小区的用户容量和前反链路差模型。对该模型,利用多目标进化算法对WCDMA功率进行了优化配置,得出了系统较优配置的一系列功率值。根据用户的满意度,建立了确定导频功率和用户业务功率的准则模型,选出了最优功率配置值。     

Oxygen sensors based on a new design concept for amperometric solid state devices

A new design for all-solid amperometric detectors was tested as an oxygen sensor in the 1%–25% v/v concentration range. The design consisted of both the working (WEs) and counter electrodes (CEs) being vacuum-deposited as non-porous Au layers on the same face of a Nafion® membrane and in contact with the gas sample. Both a three-electrode device (the reference electrode being a strip of Ag/AgCl inserted between the two Au layers) and a two-electrode one were tested. In the former case, the sensor exhibited good linearity with oxygen concentration, response times comparable to a commercial sensor but a strong dependence on humidity. The origin of the latter is not due to ohmic losses but rather to the loss of catalytic activity with decreasing water contact in the polymer. The two-electrode device exhibits signal saturation at high oxygen concentrations, which is interpreted by limitations imposed by the CE reactivity. In both cases, oxygen reduction led to an exponential current rise over a wide potential range indicating very high mass transport rates and implying that the electroactive gas reacts at the line formed by the gas/solid electrolyte/metal layer interface.     

最优实验设计的改进随机进化算法

详细阐述构造最优实验设计的原始随机进化算法,并在原始算法的基础上,拓展广度搜索,改进深度搜索,以提高最优实验设计的计算速度。通过不同规模和不同优化准则的拉丁超立方体最优实验设计,验证改进算法的应用效果。算例分析表明,改进算法能够比原始算法节省约30%～60%的机时完成最优实验设计,而且改进算法对应于优化准则的最优值与原始算法最优值的差别仅为1%～3%。可见,改进算法能够兼顾最优实验设计的计算时间和优化质量,明显提高最优实验设计的构造效率。     

A unifying view for stack filter design based on graph search methods

Stack filters are operators that commute with the thresholding operation, i.e., thresholding a signal, applying the binary filter on each thresholded binary signals, and then summing up (stacking) the results yields the same result as applying the multi-level (gray-scale) filter on the original signal. Several approaches for designing optimal stack filters from training data, where optimality is characterized in terms of costs based on input-output joint observations, have been proposed. This work considers stack filter design from training data under a general statistical framework developed in the context of morphological image operator design. This framework (1) provides a common point of view for distinct design approaches, being useful for comparative analysis or for emphasizing differences, (2) clearly answers the issue of why binary signals from different threshold levels, although following distinct distributions, can be pooled together in the cost estimation process, and (3) helps to show that several stack filter design approaches based on lattice diagrams search methods share a common underlying formulation.     

基于BIM模型的结构设计审查方法研究

建筑信息模型(BIM)作为建筑工程的数字化表达,正在成为实现建筑全生命期信息化、工业化和智能化的重要手段.以BIM模型作为设计交付成果是未来建筑设计领域发展趋势.然而,现阶段建筑结构设计的审查工作还是以人工手动审查为主,普遍存在主观、效率偏低且易出差错等问题.因此,以框架结构模型审查为实例,通过关系数据库方法解析BIM...