Abstract: A system and method for permitting variable information rates and improved error performance using orthogonal or near-orthogonal codes is disclosed. This is achieved by simultaneously transmitting two or more Walsh code words from a given orthogonal code set and/or by transmitting multiple shorter orthogonal codewords sequentially such that their combined length equals the original codeword. It should be emphasized that the present invention can be used with any orthogonal or near-orthogonal code set.

Abstract: This paper is concerned with designing experiments under the assumption that an analysis strategy is used that considers interactions in addition to main effects. A criterion which averages an approximation to As-efficiency over lower-dimensional projections of the design is introduced to compare designs. A columnwise design procedure is used to construct three-level designs for six factors in 18 runs. The projection efficiencies of these designs are explored and compared with designs obtained from the L 18 orthogonal array. Results are also given for designs with 14 and 17 runs.

Abstract: We consider a production system with finite buffers and arbitrary topology where service time is subject to interruptions in one of three ways, viz. machine breakdown, machine vacations or N‐policy. We develop a unified approximation (analytical) methodology to calculate the throughput of the system using queueing networks together with decomposition, isolation and expansion techniques. The methodology is rigorously tested covering a large experimental region. Orthogonal arrays are used to design the experiments in order to keep the number of experiments manageable. The results obtained using the approximation methodology are compared to the simulation results. The t‐tests carried out to investigate the differences between the two results show that they are statistically insignificant. Finally, we test the methodology by applying it to several arbitrary topology networks. The results show that the performance of the approximation methodology is consistent, robust and produces excellent results in a variety of experimental conditions.

Abstract: Taguchi experiments are designed and carried out with five critical factors that influence the solder bumping of a 200 mm (8") wafer by stencil printing method These factors are: paste types (type 3 and type 4), squeeze forces (9 and 12 lbs), snap-off heights (0 and 5 mils), aperture shapes (square and circle), and aspect ratios (25 and 275) They are varied to form a two-level L8 orthogonal array experiment Analysis of mean (ANOM) and analysis of variance (ANOVA) are used to choose the most influential factors After fixing the most influential factors, a two-level L4 orthogonal array experiment is followed to optimize the other material and process parameters Important results are summarized in this paper which could be very useful for wafer bumping with stencil printing method

Abstract: Methods of generating orthogonal codes are presented and applied in CDMA systems These methods are used in the constructing of codes of all possible lengths up to 256 We also present orthogonal codes generated by Kronecker matrix products, called extended orthogonal codes which are used in concatenating orthogonal sequences This approach allows individual users as well as groups of users (forming microcells, cell-sectors or beams), to be separated orthogonally In addition, we examine complex, polyphase and other orthogonal code designs

Abstract: This paper describes a design optimization procedure based on a genetic algorithm combined with the finite element method. It adopts the concepts of Orthogonal Array for design parameter settings, and Signal-to-Noise Ratio (S/N) for evaluating the individual fitness. Taking advantage of the unique features of genetic algorithms, the robust solution is achieved by a rapid global search. The approach is applied to the robust design problem of a magnet actuator to demonstrate its effectiveness.

Abstract: A method for generating a memory of various sizes and configurations uses a plurality of banks. The banks are selected to meet memory requirements and size constraints and are arranged in an orthogonal array. Critical paths are minimized using commercially available software.

Abstract: The known methods for constructing complete sets of mutually orthogonal frequency squares all yield one of two parameter sets. We show that almost all these constructions can be derived from one basic design theory construction.

Abstract: [This abstract is based on the author's abstract.] There was a high defect level (about 6000 ppm) are a plant that makes printed circuit assemblies through the wave soldering process. Because of the high defect level, 100% inspection and much rewo..

Abstract: A recent theorem of Schmid and Lawrence establishes an equivalence between (T, M, S)-nets and ordered orthogonal arrays. This leads naturally to a search both for constructions and for bounds on the size of an ordered orthogonal array. Subsequently, Martin and Stinson used the theory of association schemes to derive such a bound via linear programming. In practice, this involves large-scale computation and issues of numerical accuracy immediately arise. We propose a hybrid technique which gives lower bounds — obtained in exact arithmetic — on the number of rows in an ordered orthogonal array. The main result of the paper is a table showing the implications of these bounds for the study of (T, M, S)-nets.

Abstract: A methodology based on the coupling of experimental design and a modified simplex method is proposed for the optimization of a new flow injection-kinetic system for the spectrophotometric determination of Os (IV) with m-acetylchlorophosphonazo, which has for the first time been used as chromogenic reagent in the quantitative analysis of this element. An orthogonal array design is utilized to design the experimental protocol, in which six variables are varied simultaneously, and obtain the initial simplex using 25 experiments. A modified simplex method is applied to continuously optimize the data of the orthogonal array design; the search for optimum conditions of 6 variables using the modified simplex method required only 25 experiments. The efficiency and simplicity of the coupling of the experimental design and the modified simplex method are attractive for the development of new analytical methods. The method has been applied to the determination of Os (IV) in a refined ore as well as in a secondary alloy and provided satisfactory results.

Abstract: This paper proposes an optimal design scheme to improve the muffler’s capacity of noise reduction of the exhaust system by combining the Taguchi method and a fractional factorial design. As a measuring tool for the performance of a muffler, the performance prediction software which is developed by Oh, Lee and Lee (1996) is used, In the first stage of a design, the length and radius of each component of the current muffler system are selected as control factors. Then, theL 18 table of orthogonal arrays is adopted to extract the effective main factors. In the second stage, the fractional factorial design is adopted to take interactions into consideration, which theL 18 table of orthogonal arrays can not consider. For an optimal design, theL 27 table of orthogonal arrays with main and interaction effects is proposed and the noise factors such as temperature, background noise and humidity are analyzed for more efficient design simultaneously.

Abstract: It is well-known that all orthogonal arrays of the form OA(N;t+1;2;t) are decomposable into ‚ orthogonal arrays of strength t and index 1. While the same is not generally true when s = 3, we will show that all simple orthogonal arrays of the form OA(N;t + 1;3;t) are also decomposable into orthogonal arrays of strength t and index 1.

Abstract: A controller synthesis algorithm is developed in this paper. The algorithm employs the genetic algorithm for parameter optimization and Taguchi method for the planning of trials in applying the genetic algorithms. The resulting two-phase algorithm explores the orthogonal array in Taguchi method to conduct a series of experiments so that key parameters pertaining to the control factors, noise factors, and quality factors can be determined. In the first phase, a matrix-type experiment is conducted to determine the configuration for parameter optimization. The second phase then applies parameter optimization method to determine the controller parameter that leads to robust performance. The combined two-phase approach is effective and efficient in controller synthesis. The proposed algorithm is applied to a control-design benchmark problem. The resulting design is shown to have a superior performance to other existing controllers.

Abstract: The local search with orthogonal design of experiment in its neighborhood determination (ODLS) outperforms the local search with the conventional neighborhood when the objective function includes noise. This models practical optimization problems that contains uncontrolled or unobserved variables. ODLS is robust and e cient since it shares all evaluations for direction determination of each variable. We illustrate the characteristics and demonstrate its performance in simple quadratic function plus random noise, and discuss their improved parallel processing capability from the conventional local search.

Abstract: INTRODUCTION This paper describes the development of a generic multidisciplinary design optimization tool, which enables any user to mount his or her application program on top of the tool to perform an optimized system design without having to do all the required work in performing multidisciplinary design optimization. This optimum design tool uses the simulation-based approach, in lieu of the traditional search-based approach. The generic tool is written in Microsoft Excel, which combines three different techniques: Taguchi techniques, fuzzy logic and neural networks, into one platform. This tool is designed to be user-friendly and interactive. It is also flexible enough to allow the user to easily switch between single and multiple objective optimizations, and between local and global optimizations, at any time. Furthermore, the user can place a preference weight on each objective. Two types of optimization programs are available to the user. The first one is for the case when the user does not have a database containing input-output pairs. The second one assumes that the user already has such database, and as soon as an optimum design is found, the user has a choice to fine-tune it by slightly changing some design parameter values. * Professor, Mechanical Engineering Department f Research Scientist Copyright © 2000 by the American Institute of Aeronautics and Astronautics, Inc. No copyright is asserted in the United States under Title 17, U.S. code. The U.S. Government has a royaltyfree license to exercise all rights under the copyright claimed herein for Governmental purposes. All other rights are reserved by the copyright owner. The emerging field of Multidisciplinary Design Optimization (MDO) seeks to improve design methodology to rapidly and efficiently explore multipledimension design spaces with the goal of increasing system performance significantly, thereby reducing endproduct cost substantially. Search-based and simulation-based are the two major system design approaches. The former is traditional and mathematical, and has been existing for a long time. The optimum solution has to do with the selected starting point, and the optimization method used. A possibility of divergence in solution seeking is a major drawback in this approach. In contrast, the simulationbased approach uses the analysis and evaluation of a candidate solution, and the assessment of the degree to which the candidate satisfies the requirement. This optimum design tool uses the simulation-based approach'. With this new approach, the optimum solution can be obtained in real time. This powerful tool combines Taguchi techniques, fuzzy logic and neural networks in one platform. Traditionally, global optimization is much more difficult and time consuming to perform using the search-based approach. A common searching technique in global optimization is known as multi-start, in which the user keeps changing the starting point until no better solution can be found. In contrast, the presented design American Institute of Aeronautics and Astronautics (c)2000 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization. tool can easily perform global optimization as well as local optimization. In local optimization, the user can specify the allowable range from the design baseline. With the simulation-based approach, global optimization is merely a special case of local optimization. COMBINING THE THREE TECHNIQUES FOR OPTIMIZATION In this work, the simulation-based optimization is accomplished by combining Taguchi techniques, fuzzy logic and neural networks. They are briefly described below (A) Taguchi Techniques The Taguchi techniques developed by Dr. Taguchi are cost driven and highly efficient in their ability to extract relatively large amount of information from small experiments'. Taguchi has created a transformation of the repetition data to another value, which is a measure of the variation present. This transformation is the signal-to-noise (S/N) ratio. By examining the S/N ratios, the relative parameter significance can be determined, which provides a basis for parameter settings in optimization later. Table I Taguchi's Orthogonal Array L27 (3) The basic tools used to obtain the information are orthogonal arrays and linear graphs. Three valuable pieces of information are generated from a Taguchi analysis: 1. Which factors or parameters are significant to the output (or objective functions) 2. The relative significance of those factors 3. Which direction for levels of those factors will lead to further improvement or optimization to the design An orthogonal array contains the number of experimental runs, the number of levels of each input parameter, and the number of columns in the array. In an orthogonal array, every input parameter is placed in one of the columns. Table I shows an example of a Taguchi's orthogonal array, L2?(3), which can be used for up to 13 parameters with 3 levels (such as 1 for low, 2 for medium, and 3 for high). In this case, only a total of 27 runs or experiments are needed to identify the significant parameters. (i| 1 1 1 1 1 1 1 1 1 1 1 ff 1 1 1 1 2 2 2 2 2 2 2 111 1 1 1 1 3 3 3 3 3 3 3 1 2 2 2 1 1 1 2 2 2 3 1 2 2 2 2 2 2 3 3 3 1 1 2 2 2 3 3 3 1 1 1 2 i p 1 3 3 3 1 1 1 3 3 3 2 ltj!f 1 3 3 3 2 2 2 1 1 1 3 ( • 1 3 3 3 3 3 3 2 2 2 1 2 1 2 3 1 2 3 1 2 3 1 |fl< 2 1 2 3 2 3 1 2 3 1 2 illl 2 1 2 3 3 1 2 3 1 2 3 2 2 3 1 1 2 3 2 3 1 3 •Jl 2 2 3 1 2 3 1 3 1 2 1 <1|| 2 2 3 1 3 1 2 1 2 3 2 • 2 3 1 2 1 2 3 3 1 2 2 2 3 1 2 2 3 1 1 2 3 3 ; 2 3 1 2 3 1 2 2 3 1 1 : 3 1 3 2 1 3 2 1 3 2 1 3 1 3 2 2 1 3 2 1 3 2 3 1 3 2 3 2 1 3 2 1 3 3 2 1 3 1 3 2 2 1 3 3 3 2 1 3 2 1 3 3 2 1 1 111! 3 2 1 3 3 2 1 1 3 2 2 ll|l 3 3 2 1 1 3 2 3 2 1 2 I|ji 3 3 2 1 2 1 3 1 3 2 3 3 3 2 1 3 2 1 2 1 3 1 2 2 3 3 1 1

Abstract: The design of experiment(DOE) is getting more attention in the engineering community since it is easy to understand and apply. Recently, engineering designers are adopting DOE with orthogonal arrays when they want to design products in a discrete design space. In this research, a design flow with orthogonal arrays is defined for structural design according to the general DOE. The design problem is defined as a general structural optimization problem. Sensitivity information is evaluated by the analysis of variance(ANOVA), and an optimum design is determined from analysis of means(ANOM). Interactions between design variables are investigated to achieve additivity which should be valid in DOE. When strong interactions exit, a method is proposed. Some methods to consider the problem are suggested.

Abstract: In the traditional approach to experimentation, experimenters may vary one factor or variable, keeping all other factors in the experiment fixed. This is also called the one-factor-at-a-time approach to experimentation. Here a factor refers to a controlled or uncontrolled variable where influence upon a response (or output) is studied during the experiment [1]. A factor can be either qualitative (i.e. different detergents, machines, vendors, catalysts and so on) or quantitative (i.e. pressure, time, temperature, speed and so on).

Abstract: The design process of the motor driven tilt/telescopic steering column is established by axiomatic design approach in conceptual design stage. By selecting independent design variables for improvin g performance of the steering system, each detailed design can be carried out independently. In the detailed design, the safety in crash environment and vibration reduction are considered. An occupant analysis code SAFE(Safety Analysis For occupant crash Environment) is utilized to simulate the body block test. Segments, contact ellipsoids and spring-damper elements are used to model the steering column in SAFE. The model is verified by the result of the body block test. After the model is validated, the energy absorbing components are designed using an orthogonal array. Occupant analyses are performed for the cases of the orthogonal array. Final design is determined for the minimum occupant injury. For vibrational analysis, a finite element model of the steering column is defined for the modal analysis. The model is validated by the vibration experiment. Size and shape variables are selected for the optimization process. An optimization is conducted to minimize the weight subjected to various constraints

Abstract: Taguchi experiments are designed and carried out with five critical factors that influence the solder bumping of a 200 mm (8 in) wafer by stencil printing method. These factors are: paste types, squeeze forces, snap-off heights, aperture shapes, and aspect ratios. They are varied to form a two-level L8 orthogonal array experiment. Analysis of mean (ANOM) and analysis of variance (ANOVA) are used to choose the most influential factors. After fixing the most influential factors, a two-level L4 orthogonal array experiment is followed to optimize the remaining material and process parameters. Important results are summarized in this paper which could be very useful for wafer bumping with stencil printing method.

Abstract: Testers face the challenge of doing as much testing as possible within the available, and usually constrained, schedule. It is not practical to exhaustively test all combinations of system test cases. There are methods that generate a small subset of test cases that provide good coverage of the test domain. This paper discusses the author's experience with two such methods—Taguchi (orthogonal array) techniques and the Combinatorial Design Method (CDM). The CDM has proven to be more flexible for system level testing of commercial satellite ground systems.