Showing papers on "Orthogonal array published in 2001"

Design of Experiments Using The Taguchi Approach: 16 Steps to Product and Process Improvement

Abstract: What is design of experiments and Taguchi approach definition and measurement of quality common experiments and methods of analyses experiment designs using orthogonal arrays experiments with 2-level factors only experiments with 3-level and 4-level factors analysis of variance (ANOVA) experiments to study interactions between factors experiments design with mixed level factors combination designs strategies for robust design analysis using signal to noise ratios(S/N) results comprising of multiple criteria of evaluations quantification of variation reduction and performance improvement effective experiment preparation and planning example case studies.

Optimal and orthogonal Latin hypercube designs for computer experiments

Abstract: SUMMARY Latin hypercube designs are often used in computer experiments as they ensure that few design points are redundant when there is effect sparsity. In this paper, designs suitable for factor screening are presented and they are shown to be efficient in terms of runs required per factor as well as having optimal and orthogonal properties. Designs orthogonal under full second-order models are also constructed.

A quality study on the excimer laser micromachining of electro-thermal-compliant micro devices

Abstract: The objective of this research is to improve the quality of the KrF excimer laser micromachining of metal and silicon in fabricating electro-thermal-compliant (ETC) micro devices. The ETC devices combine the actuator and the mechanism into one monolithic compliant continuum and enable a range of mechanical manipulation tasks at micron scale. An efficient method for optimizing the process parameters in laser micromachining, using the orthogonal array-based experimental design method, is presented in this paper. The feed rate of the XY stage, the laser pulse frequency, the discharge voltage and the number of passes were used as the control parameters. The roughness of the machined edge was used as the primary indicator of cutting performance. The roughness of the edges was computed automatically from the optical image of the machined samples. The heat-affected zone, kerf width and rate of cutting depth (depth per one pass) were used as additional quality indicators. The orthogonal array method enabled the optimization of the control parameters by reducing the required number of experiments compared to the traditional full factorial experiment. Furthermore, machining in a liquid environment improved the quality and eliminated more debris and recast compared to machining in the air.

Space-Time Diversity Using Orthogonal and Amicable Orthogonal Designs

Abstract: In this paper we consider the utilization of multiple transmitter and receiver antennas for space-time diversity. The optimal SNR scheme, which also provides the best diversity, is outlined. This scheme however involves a reduction in the data rate. Coding schemes are then presented which not only achieve the optimal SNR but also mitigate the reduction of data rate. The proposed schemes are based on the theory of Orthogonal Designs and Amicable Orthogonal Designs.

Sixteen run designs of high projectivity for factor screening

Abstract: A two level orthogonal array design for n observations with k factors and of projectivity P provides an (n, k, P) factor screen for which every projection into P space produces a complete 2 P factorial, possibly with certain points replicated. Box and Tyssedal [1] rigorously investigated the screening properties of such designs derived from fractional factorials and Plackett Burman orthogonal arrays (OA's). For example, they showed that these always provided (12, 11, 3) and (20, 19, 3) screens, but for 16 runs only a (16, 8, 3) screen could be generated. In this paper it is shown that designs derived from a different class of OA's due to Hall [2] can produce sixteen run designs that can screen a larger number of factors and that in particular (16, 12, 3) screens and also a (16, 14, 3) screen can be obtained.

Taguchi concepts and their applications in marine and offshore safety studies

Abstract: Taguchi concepts have been developed into an engineering method of quality improvement referred to as Quality Engineering in Japan and as Robust Design in the West, which is a disciplined engineering process that seeks to find the best trade-off of a product design. A safety optimization framework using Taguchi concepts is proposed in this paper. An example is used to demonstrate the application of the framework in maritime safety studies. Following a brief review of Taguchi concepts and techniques used in Robust Design, this paper discusses how the Taguchi concepts such as 'quality loss function', 'signal-to-noise ratio', 'orthogonal arrays', 'degree of freedom' and 'analysis of variance' may be synthesized in maritime safety engineering studies. Brainstorming, an integral part of the Taguchi philosophy, is also briefly discussed. Orthogonal arrays are used to study many parameters simultaneously with a minimum of time and resources to produce an overall picture for more detailed safety-based design and ...

Some new HSOLSSOMs of types hn and 1m u1

Abstract: In this paper, two new direct construction methods are given for holey self-orthogonal Latin squares with a symmetric orthogonal mate (HSOLSSOMs). Some new HSOLSSOMs using already known methods are also given. The known existence results for HSOLSSOMs of types 1mu1 and hn are improved; for type 1mu1 there remain just four possible exceptions with u odd and 3 ≤ u ≤ 15; for type hn, there are just two possible exceptions remaining, for (h, n) = (6, 12) and (6, 18). As a byproduct, the known existence results for three holey mutually orthogonal Latin squares (3 HMOLS) are also improved. © 2001 John Wiley & Sons, Inc. J Combin Designs 9: 435–444, 2001

Analysis of orthogonal array experiments using the multivariate orthogonal regression method

Abstract: A multivariate orthogonal regression method is presented for analyzing data from orthogonal array experiments. The least squares method is used to fit data with an orthogonal polynomial regression model to obtain the same statistical test results as..

New Optimization Strategy for Chemical Mechanical Polishing Process

Abstract: In this study, a systematic approach to achieve a globally optimal Chemical Mechanical Polishing (CMP) process is carried out. In this new approach, the orthogonal array technique adopted from the Taguchi method is used to realize an efficiently experimental design. The RBFNF neural-fuzzy network is then applied to model the complex CMP process. The signal-to-noise ratio (S/N) analysis (ANOVA) technique used in the conventional Taguchi method is also implemented to obtain the local optimum process parameters. The globally optimal parameters are successively acquired in terms of the trained RBFNF network. In order to increase CMP throughput, a two-stage optimal strategy is also proposed. Experimental results demonstrate that the two-stage strategy performs better than the original approach even though the total processing time is reduced by 1/6.

Theory & Methods: Cutting Experimental Designs into Blocks

Abstract: Summary Most experimental material in agriculture and industry is heterogeneous in nature and therefore its statistical analysis benefits from blocking. Many experiments are restricted in time or space, and again blocking is useful. This paper adopts the idea of orthogonal blocking of Box & Hunter (1957) and applies it to optimal blocking designs. This approach is then compared with the determinant-based approach described in the literature for constructing block designs.

A simulated air bearing analysis by design of experiments and its applications in optimization

Abstract: This study presents an air-bearing design procedure by using Taguchi's Design of Experiments (TDE) to simulate the analysis of systems without adequate models. Instead of taking data from experiments, the performance of air bearings is obtained by an empirical verified numerical model. This arrangement eliminates the errors inevitably introduced in tests. When comparing with full factorial analysis, the number of tests is significantly reduced by using TDE in the demonstrated study. The optimum set of the variables predicted by TDE is numerically verified in the cases investigated. The analysis of orthogonal arrays consisting of three levels shows better performance prediction than the two levels analysis. The straightforward and easy to use procedure can be applied conjunction with numerical optimization technique to give an excellent start-point to minimize search time in a multi-variable design as illustrated in this report. Presented as a Society of Tribologists and Lubrication Engineers Paper at the ...

Dynamic bandwidth allocation in a satellite communication network

Abstract: Our work deals with ATM satellite communications networks employing DAMA, whose algorithm must be efficient and robust. Its efficiency ensures a fast response to a connection's demand for bandwidth. Its robustness ensures satisfaction of the connection's required QoS and its integrity under unpredictable traffic burstiness. Computational practicality dictates that only heuristic DAMA algorithms be implemented in an ATM satellite communications system. But these heuristic algorithms need be validated and benchmarked before they are fielded. In this work, we employ the orthogonal array experiment (or the Taguchi method) to allocate bandwidth in a satellite communications network. We also validate and benchmark the Taguchi assignments with the results obtained by mathematical optimization. This benchmarking process allows us to quantitatively assess the performance of our approach and is recommended to be employed when developing heuristic algorithms. The close agreement between the results produced by the orthogonal array experiment method and the conventional integer programming solution methods underscores the feasibility of the orthogonal array experiment approach.

Development of an Optimization Algorithm Using Orthogonal Arrays in Discrete Design Space

Abstract: The structural optimization have been carried out in the continuous design space or in the discrete design space. Methods fur discrete variables such as genetic algorithms , are extremely expensive in computational cost. In this research, an iterative optimization algorithm using orthogonal arrays is developed for design in discrete space. An orthogonal array is selected on a discrete des inn space and levels are selected from candidate values. Matrix experiments with the orthogonal array are conducted. New results of matrix experiments are obtained with penalty functions leer constraints. A new design is determined from analysis of means(ANOM). An orthogonal array is defined around the new values and matrix experiments are conducted. The final optimum design is found from iterative process. The suggested algorithm has been applied to various problems such as truss and frame type structures. The results are compared with those from a genetic algorithm and discussed.

Design method for high reliable flip chip BGA package

Abstract: An efficient design method for flip chip ball grid array (BGA) packages has been developed. This method uses design of experiment (DOE), a series of finite element (FE) stress analyses based on an orthogonal array used in DOE, and statistical analysis. By using this method to design a BGA package having 1600 pins, the warpage of the optimum packaging structure is very small and all of the reliability demands are satisfied.

Clique Facets of the Orthogonal Latin Squares Polytope É

Abstract: Since 1782, when Euler addressed the question of existence of a pair of Orthogonal Latin Squares (OLS) by stating his famous conjecture ([8, 9, 13]), these structures have remained an active area of research due to their theoretical properties as well as their applications in a variety of fields. In the current work we consider the polyhedral aspects of OLS. In particular we establish the dimension of the OLS polytope, describe all cliques of the underlying intersection graph and categorize them into three classes. For two of these classes we show that the related inequalities have Chvatal rank two and both are facet defining. For each such class, we give a separation algorithm of the lowest possible complexity, i.e. linear in the number of variables.

Device optimization using response surface methodology with orthogonal arrays

Abstract: An optimization technique that expands the application of response surface methodology (RSM) of conventional design-of-experiments techniques into the utilization of the Taguchi method's orthogonal arrays is proposed to improve the efficiency of RSM. A case study of NMOS device-window check of threshold voltage is used to illustrate the implementation of this method.

Design Optimization on Cost Basis Using Orthogonal Arrays

Abstract: This paper describes the approach used in a cost optimization study for a single-stage-to-orbit launch vehicle. Taguchi's experimental designs called orthogonal arrays are utilized for efficiently studying the effect of different material and technology options on design, development, test and evaluation cost. The results suggest that the approach taken facilitates rapid evaluation on a cost basis early in the design phase and may lead to reduced project costs.

Improved time-frequency synthesis using array manifolds

Abstract: The source array manifold can be used to improve signal synthesis from the Wigner-Ville distribution (WVD). In the proposed approach, the inner products of source array vectors translate into weighting factors that reduce the crossterms between the source signals, and thus yield improved synthesis. Orthogonal array manifold vectors remove any interaction between their respective source waveforms in the time-frequency (t-f) domain. For Gaussian channel and omni-directional antennas, the spatial signature estimation and the quality of the synthesized signals impinging on a multi-antenna receiver depend on the angular separation of the sources as well as the source t-f characteristics. Evaluations of the proposed technique in terms of performance and computations are provided.

Fuzzy control algorithm for multi-objective problems by using orthogonal array and its application to an AMB system

Abstract: A new fuzzy logic control design algorithm suitable for multiobjective control problems is proposed based on the orthogonal array that is widely used for design of experiments in statistics and industrial engineering. The essence of the algorithm is to introduce an n-th order certainty factor for each rule defined from its F-value, in order to effectively exclude the less confident rules and rate the rules. The proposed algorithm with multiobjective decision table (MODT) is found to be capable of detection of inconsistency and the rule classification, reduction and modification. It is also shown that the algorithm can be successfully applied to the fuzzy controller design of a rigid rotor-active magnetic bearing (AMB) system with model uncertainties.

자동차 옆문 충격빔의 최적설계

Abstract: As the solution of the automotive frontal crashworthiness is settled, side impact problem becomes challengeable. The door stiffness is the most important factor for the side impact. Generally, researches have been conducted on the assembled door. A side impact door beam is installed in a door to protect occupants from the side impact. The research is only concentrated on the side impact beam and a side impact beam is designed. The cross section is defined to have an elliptic shape. An optimization problem is defined to minimize the weight of the structure while various constraints are satisfied. Design variables are the radii and the thickness of the ellipsoid. The analysis of the side impact is carried out by the nonlinear finite element method. The optimization problem is solved by two methods. An orthogonal array is established around the existing design. Since the radii are included in the design variable set, a finite element model is made for each row of the array. Firstly, the formulated problem is solved by an algorithm which can handle constraints with orthogonal arrays. Secondly, the response surface method (RSM) is utilized. The functions are approximated by the information from the orthogonal array. Both methods can obtain better designs than the current one.

Gendex: NOA Module for Constructing Orthogonal and Near-Orthogonal Arrays and Main Effect Plans

Abstract: The NOA module of the Gendex toolkit may be used to obtain 2-level main effect plans for 2 to 128 factors, for constructing orthogonal or near-orthogonal arrays, and for constructing supersaturated fractional replicates of a complete factorial In addition, a 2level main effect plan may be augmented with single degree of freedom contrasts for a k-level factor with this module An explanation of the steps to construct a plan is given Several examples are presented to illustrate various features of the NOA module

Construction of Lower Discrepancy OA-Based Latin Hypercube Designs

Abstract: In this paper, using uniform design and orthogonal array we give a method of constructing lower discrepancy OA-based Latin hypercube designs. The designs constructed by this method have not only good uniformity and also orthogonality. Another advantage is that design point sets of large size can constructed. Also, this paper give some uniform design tables and these designs are better than existing uniform designs.

Simultaneous Optimization of Multiple Responses to the Combined Array

Abstract: In the Taguchi parameter design, the product-array approach using orthogonal arrays is mainly used. However, it often requires an excessive number of experiments. An alternative approach, which is called the combined-array approach, was suggested by Welch et al (1990) and studied by Vining and Myers (1990) and others. In these studies, only single respouse variable was considered. We propose how to simultaneously optimize multiple responses when there are correlations among responses.