Array Pattern Optimization for Steerable Circular Isotropic Antenna Array Using Cat Swarm Optimization Algorithm

In this paper the steerable isotropic circular array antenna is designed for reducing the side lobe level (SLL) using evolutionary optimization technique. The optimization techniques particle swarm optimization and cat swarm optimization algorithm are used to reduce the SLL as well as to steer the main beam in specific direction. In this design of steerable circular arrays the amplitude excitations are optimized. Obtained results show that the maximum peak of SLL of the resultant patterns are as per requirement. This paper present a good performance in the array factor response and suppressed SLL for different number of array elements with different steering angle of the main beam using evolutionary optimization technique.     

Implementation of a decoupled optimization technique for design ofswitching regulators using genetic algorithms

This paper presents an implementation of a decoupled optimization technique for design of switching regulators using genetic algorithms (GAs). The optimization process entails the selection of component values in a switching regulator, in order to meet the static and dynamic requirements. Although the proposed method inherits characteristics of evolutionary computations that involve randomness, recombination, and survival of the fittest, it does not perform a whole-circuit optimization. Thus, intensive computations, that are usually found in stochastic optimization techniques can be avoided. Similar to many design approaches for power electronics circuits, a regulator is decoupled into two components, namely the power conversion stage (PCS) and the feedback network (FN). The PCS is optimized with the required static characteristics, whilst the FN is optimized with the required static and dynamic behaviors of the whole system. Systematic optimization procedures are described and the technique is illustrated with the design of a buck regulator with overcurrent protection. The predicted results are compared with the published results available in the literature and are verified with experimental measurements     

Optimizing Zero-Forcing Precoders for MIMO Broadcast Systems

In this paper, we develop optimization techniques for linear zero-forcing (ZF) multiple-input, multiple-output (MIMO) broadcast (BC) precoders. A computationally efficient technique based on QR-update algorithms for implementing this optimization is then proposed. The application of the proposed ZF precoders and decoders to systems with both large and small numbers of users is considered. The proposed optimization technique is also shown to perform very well in conjunction with nonlinear Tomlinson--Harashima precoding. Both coded and uncoded performances are considered.     

IC优化设计的参数抽样效益折衷算法

本文对效益函数进行了扩展,提出了IC最优化设计的参数抽样效益折衷方法,较好地解决了IC统计多目标优化非劣解的协调问题,得到了一种改进的Monte Carlo成品率最优化设计方法.     

k-out-of-m system availability with minimum-costallocation spares

An optimization method for determining the number of spare units that should be allocated to a k-out-of-m system to minimize the system-spares cost yet attain the specified system availability is presented. The objective function for optimization is a nonlinear integer type. The optimization method is a variation of the simplex search technique used for continuous functions. The optimization problem is cast in a form that minimizes the system-spares cost, with the required system availability as an inequality constraint. Results obtained by using the proposed optimization technique, as well as the computation time required for optimization, are compared to those for methods developed specifically for dealing with nonlinear integer problems. The method is simple, easy to implement, and yet very effective in dealing with the spare allocation problem for k-out-of-m:F systems     

Design and optimization of double-RESURF high-voltage lateral devices for a manufacturable process

A simple method for determining the optimal charge balance and processing window of double-reduced surface field (RESURF) lateral devices is presented. The technique is based on the use of simple two test structures that are widely used in ICs, no special test structures are required. The optimal processing window is determined from the bounds over which RESURF is maintainable, and hence, high breakdown voltage is achievable. Using the technique, device designers can set and choose the process conditions of the device's critical layers to yield a manufacturable process prior to actual device layout, and therefore preserves the ability for layout design optimization independent of process optimization. The proposed technique also maximizes the benefits of double-RESURF processing for achieving the lowest on-resistance while maintaining the desired breakdown voltage. Using the technique, the process design and optimization guidelines for a double-RESURF LDMOS built in a high voltage IC technology are discussed and supported with experimental results.     

The application of optimization techniques in the study of Schottky-barrier devices

In this paper, we discuss a numerical optimization technique which may be used to study the effect of interface states on the terminal characteristics of Schottky-barrier devices. The numerical technique is based on the minimization of the sum of residuals obtained by comparing accurate experimental data with a generalized theoretical model. The analysis used in the present study is based on Heine's model and takes the interfacial charges into account. The terminal characteristics of Au-Si Schottky-barrier devices are studied and analyzed. Information regarding interface state density, barrier height, etc., is obtained by using the optimization procedure in conjunction with the current-voltage and capacitance-voltage characteristics of these devices. Consistent values for the device parameters have been obtained through the utilization of the optimization technique.     

Design, modeling, and optimization of mechanically reconfigurableaperture antennas

The work in this study develops the framework for placement and actuation of novel reconfigurable dual-offset contour beam reflector antennas (DCBRA). Toward that end, the methodology for the antennas' design is defined. In addition, two separate optimization problems are stated and solved: actuator position optimization and actuation value optimization. For the former, a method termed as greatest error suppression method is proposed where the position of each actuator is decided one by one after each evaluation of the error between the desired subreflector shape and the actual subreflector shape. For the second problem, a mathematical analysis shows that there exists only one optimal configuration. Two optimization techniques are used for the second problem: the simulated annealing algorithm and a simple univariate optimization technique. The univariate technique always generates the same optimal configuration for different initial configurations and it gives the low bound in the evaluation of the error. The simulated annealing algorithm is a stochastic technique used to search for global optimum point. Finally, as an example the results of the proposed optimization techniques are presented for the generation of a subreflector shape corresponding to the geographical outline of Brazil     

Synthesis of Optimal Sum and Difference Patterns from Time Modulated Hexagonal Planar Arrays

An efficient array synthesis technique is developed for the design of optimal monopulse antennas in time modulated planar arrays with triangular lattices and hexagonal boundaries. Major emphasis is laid on the realization of low sidelobe array patterns from uniform amplitude excitations, and the inherent sideband radiations in time modulated arrays are suppressed to a sufficient low level. The synthesis technique implements the differential evolution strategy (DES) as the optimization tool, and a fast computation method based on 2D Fast Fourier Transform (FFT) is employed to speed up the optimization. Numerical results show that with the aid of the time modulation technique, the sum, difference, and double-difference patterns are obtainable from an array with fixed uniform amplitude excitations, thus demonstrating the effectiveness and validity of the proposed technique.     

A new formulation technique for local torque optimization ofredundant manipulators

A new formulation technique called “torque-based formulation” for the local torque optimization of redundant manipulators is introduced in this paper. The formulation based on joint torques makes the pseudoinverse and recursive techniques possible to local torque optimization. The local torque optimization approaches that are formulated on the basis of the proposed formulation technique are simple in formulation and are efficient in computational cost. Equivalence between the proposed solutions for local torque optimization and the conventional solutions is also proven analytically     

Space-time correlation theory for information-carrying signals

A theory is presented for the analysis and optimization of systems which process electromagnetic fields carrying information. The theory is thus intended for use primarily by communications and radar engineers. The definitions are motivated by a fundamental requirement that the input-output space-time mutual information transfer be a maximum. The theory can be applied to problems involving nonstationary and nonergodic processes in space and time. The technique proposed is particularly useful in the analysis and optimization of controlled systems carrying man-made information, such as radar and communications. System optimization is carried out by maximization of the trans-correlation function with respect to the variable parameters of the system. The transcorrelation function is a space- and time-averaged correlation function between the desired and the actual system outputs. The optimization technique is applied to the problem of an antenna embedded in a nonstationary medium, such as a hot plasma. The amplitude and phase shading of the array are the variable parameters chosen for optimization of the system, and medium effects, background (object) noise, receiver noise, etc., are considered.     

Applying material optimization to fracture mechanics analysis to improve the reliability of the plastic IC package in reflow soldering process

To prevent crack propagation in a plastic small outline J-lead package with a dimpled diepad under an IR soldering process, parametric study and optimization with respect to material properties are done. The main design variables among all material properties are determined from the parametric study. Their optimized values are determined by applying a constraint optimization technique to the IC package.     

An Optimization Technique for Lumped-Distributed Two Ports

A frequency domain direct efficient analysis and an optimization technique of a large class of lumped-distributed networks containing active elements are presented. Sensitivity and Hessian matrix calculations are performed using truncated Taylor series expansion of two-port parameters of subnetworks. An interactive computer program was developed to demonstrate the application of the method. Examples of network optimization are included to illustrate the powerfuless of the technique.     

Enhancing the Convergence Speed of Space Mapping Technique in Cylinder Conformal Antennas Optimization

Space mapping (SM) technique is applied in conformal antenna design. The main idea of this technique is to map the coarse model of a planar layer structure microstip antenna to fine structure of a conformal antenna including platform through space mapping. This technique is very suitable for conformal antenna optimization where long computational time is required to achieve an accurate solution. As the convergence speed of this technique is related to the response functions, some response functions are researching for accelerating the optimization. Two examples are studied to validate the advantages of the feasible response functions for accelerating the convergence speed of SM technique.     

Optimizing ZF Precoders for MIMO Broadcast Systems

In this paper, we develop optimization techniques for linear zero-forcing (ZF) multiple-input multiple-output (MIMO) broadcast (BC) precoders. A computationally efficient technique based on QR-update algorithms for implementing this optimization is then proposed. The application of the proposed ZF precoders and decoders to both large and small (in terms of the number of users) systems is considered. It is also shown that the proposed optimization technique is robust, and performs very well with nonlinear Tomlinson--Harashima precoding. Both coded and uncoded performances are considered.      

Performance optimization of CMOS second generation current conveyors using a multi-swarm algorithm

This paper proposes an enhanced variant of the particle swarm optimization technique PSO-2S, and its application to analogue circuit performance optimization. For comparison reasons, we focus on performance optimization of a second generation CMOS current conveyor, for different bias current values. It is worth noting that the approach can be easily adapted to deal with other types of circuits. The paper shows that PSO-2S achieves better results than three other well-known optimization techniques, namely bacterial foraging optimization technique (BFO), PSO and differential evolution (DE).     

Application of boundary-tracking gradient-method for optimizingspares cost for k-out-of-n:G systems

This paper presents an application of a classical method of steepest-descent optimization coupled with a boundary-tracking technique to solve the integer spare allocation problem for k-out-of-n:G systems. The objective function for the optimization is linear and subject to a nonlinear availability constraint. The constrained problem is solved in an unconstrained manner using a multiple-gradient technique. The search along the function gradient (unit cost) aims to locate the desired optimum on the constraint boundary. A recovery move to the feasible region is carried out if the search strays into the unfeasible region. Upon re-entry into the feasible region, a new base point for the new search direction is found along the vector sum of the gradient of the objective function and the violated constraint at the recovery point. Results for this boundary tracking multi-dimensional gradient optimization method are compared with enhanced simplical optimization and other methods developed specifically for solving integer problems. The authors' tests are carried out on systems of various numbers of subsystems. The results show appreciable improvement in execution time when compared to their earlier integer simplical optimization methods and to the Sasaki method. The improvement in CPU times is presented for comparison     

Bandwidth Optimization by Dielectric Loading

The known theory of dielectrically loaded rectangular waveguides is combined with appropriate optimization procedures to yield optimal bandwidth design. The minimal acceptable power handling capacity and/or the maximal allowed losses are used as contraints. Alternatively, power handling capacity or losses may be considered as the desired optimization targets. The numerical determination of the relevant cutoff frequencies is carried out by the efficient mode-matching technique as well as the more generally applicable moment solution. Alternative search algorithms are used and compared. Results of the optimization process are given a simple physical interpretation.     

混合搜索策略及其在VLSI冗余最优分配中的应用

容错技术对于提高VLSI电路的可靠性和成品率十分重要。为实现容错，系统必须提供冗余。本文利用模拟退火、禁忌搜索等现代优化算法求解VLSI系统中基于全局冗余的最优分配问题，并在此基础上提出结合两者优势的混合搜索策略TS^2A。实验结果表明，该方法在搜索质量上优于单一的优化方法。     

Optimization of unidirectional interdigital transducers via the scanning window technique

An original procedure for optimization of single-phase unidirectional interdigital transducers of surface acoustic waves (SAWs) is described. These transducers are designed for RF filters with low levels of the insertion loss and the triple-transit signal. The optimization algorithm is based on the so-called scanning window technique. Unlike most methods published in the literature, this technique optimizes not continuous (analog) weighting functions of the SAW sources and reflectors but the sequence of base electrode cells; i.e., the technique directly optimizes the transducer topology.