Extended Objective-Oriented Sequential Sampling Method for Robust Design of Complex Systems Against Design Uncertainty

2012 ◽  
Author(s):  
Siliang Zhang ◽  
Ping Zhu ◽  
Paul D. Arendt ◽  
Wei Chen
Keyword(s):  
Complex Systems ◽  
Robust Design ◽  
Sampling Method ◽  
Sequential Sampling ◽  
Robust Solution ◽  
Design Variables ◽  
Crashworthiness Design ◽  
The One ◽  
Uncertainty In Design ◽  
Sequential Strategy

In robust design of complex systems, metamodeling techniques are commonly used to replace expensive computer simulations. To improve the sampling efficiency, efforts have been made towards developing objective-oriented sequential sampling methods for deterministic problems. In this paper, an extended objective-oriented sequential sampling method is proposed for robust design, with an emphasis on those problems with uncertainty in design variables. The method involves quantitative assessment of the effects of metamodeling uncertainty on the robust responses, as well as a sequential strategy of choosing samples to adaptively improve the predicted robust response. To validate the benefits of the sequential strategy, two mathematical examples are illustrated first. This is followed by an automotive crashworthiness design example, a highly expensive and non-linear problem. Results show that the proposed method can mitigate the effect of both metamodeling uncertainty and design uncertainty, and more efficiently identify the robust solution compared to the one-stage sampling approach that is commonly used in practice.

On Sequential Sampling for Global Metamodeling in Engineering Design

2002 ◽  
Author(s):  
Ruichen Jin ◽  
Wei Chen ◽  
Agus Sudjianto
Keyword(s):  
Complex Systems ◽  
Engineering Design ◽  
Sequential Sampling ◽  
Test Problems ◽  
Sampling Strategies ◽  
General Applicability ◽  
One Stage ◽  
Computationally Expensive ◽  
The One ◽  
Global Metamodeling

Approximation models (also known as metamodels) have been widely used in engineering design to facilitate analysis and optimization of complex systems that involve computationally expensive simulation programs. The accuracy of metamodels is directly related to the sampling strategies used. Our goal in this paper is to investigate the general applicability of sequential sampling for creating global metamodels. Various sequential sampling approaches are reviewed and new approaches are proposed. The performances of these approaches are investigated against that of the one-stage approach using a set of test problems with a variety of features. The potential usages of sequential sampling strategies are also discussed.

scholarly journals Reliability-Based Robust Design Optimization of Structures Considering Uncertainty in Design Variables

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shujuan Wang ◽  
Qiuyang Li ◽  
Gordon J. Savage
Keyword(s):  
Sensitivity Analysis ◽  
Design Optimization ◽  
Robust Design ◽  
Structural Reliability ◽  
Computational Cost ◽  
Optimization Process ◽  
Robust Design Optimization ◽  
Global Approximation ◽  
Design Variables ◽  
Uncertainty In Design

This paper investigates the structural design optimization to cover both the reliability and robustness under uncertainty in design variables. The main objective is to improve the efficiency of the optimization process. To address this problem, a hybrid reliability-based robust design optimization (RRDO) method is proposed. Prior to the design optimization, the Sobol sensitivity analysis is used for selecting key design variables and providing response variance as well, resulting in significantly reduced computational complexity. The single-loop algorithm is employed to guarantee the structural reliability, allowing fast optimization process. In the case of robust design, the weighting factor balances the response performance and variance with respect to the uncertainty in design variables. The main contribution of this paper is that the proposed method applies the RRDO strategy with the usage of global approximation and the Sobol sensitivity analysis, leading to the reduced computational cost. A structural example is given to illustrate the performance of the proposed method.

scholarly journals Critical Investigation of the Combined Compliance Average and Spreading Measures in the Robust Topology Optimization with Uncertain Loading Magnitude and Direction

2020 ◽  
Author(s):  
Anikó Csébfalvi
Keyword(s):  
Topology Optimization ◽  
Robust Design ◽  
Response Variable ◽  
Robust Solution ◽  
Robust Approach ◽  
Robust Topology Optimization ◽  
Design Variables ◽  
Bridge Problem ◽  
Creative Contribution

The paper critically investigates the role of the combined compliance average and spreading measures in the volume-constrained continuous robust topology optimization with uncertain loading magnitude and direction. In the robust topology optimization the generally expected and most popular robustness measure is the expected compliance, In the expectancy oriented approach, the compliance increment which is needed to get the robust design is an implicitly defined response variable. In order to open the possibility of the creative contribution of the designer to the best robust design searching process, this measure is sometimes combined with a spreading-oriented measure, which may be the variance or standard deviation. The best weighting schema can be done by a try-and-error-like algorithm in which the weights are design variables and the compliance-increment remains an implicitly defined response variable. In this paper, it will be shown that all of the compliance oriented approaches which are based on a single or combined statistical measure can be replaced by a new compliance-function-shape-oriented robust approach in which the allowed-compliance-increment will be an explicitly defined design variable and for a given increment value the robust solution will be the theoretically best one. A popular volume-constrained symmetric bridge problem with uncertain loading magnitude and direction will be presented to demonstrate the viability and efficiency of the proposed robust approach.

Performance Distribution Analysis and Robust Design

2000 ◽  
Vol 123 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Jianmin Zhu ◽  
Kwun-Lon Ting
Keyword(s):  
Robust Design ◽  
Robust Parameter Design ◽  
Distribution Analysis ◽  
Performance Space ◽  
Sensitivity Distribution ◽  
Performance Sensitivity ◽  
Design Variables ◽  
Robust Parameter ◽  
Performance Distribution ◽  
Feasible Space

The paper presents the theory of performance sensitivity distribution and a novel robust parameter design technique. In the theory, a Jacobian matrix describes the effect of the component tolerance to the system performance, and the performance distribution is characterized in the variation space by a set of eigenvalues and eigenvectors. Thus, the feasible performance space is depicted as an ellipsoid. The size, shape, and orientation of the ellipsoid describe the quantity as well as quality of the feasible space and, therefore, the performance sensitivity distribution against the tolerance variation. The robustness of a design is evaluated by comparing the fitness between the ellipsoid feasible space and the tolerance space, which is a block, through a set of quantitative and qualitative indexes. The robust design can then be determined. The design approach is demonstrated in a mechanism design problem. Because of the generality of the analysis theory, the method can be used in any design situation as long as the relationship between the performance and design variables can be expressed analytically.

A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

2021 ◽  
pp. 1748006X2110661
Author(s):  
Zunling Du ◽  
Yimin Zhang
Keyword(s):  
Energy Conversion ◽  
Robust Design ◽  
Design Method ◽  
Design Stage ◽  
Structure Parameters ◽  
Time Varying ◽  
Design Variables ◽  
Reliability Method ◽  
Overall Efficiency ◽  
Axial Piston

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

scholarly journals Differences in Entrepreneurial Skills of College Students in the Mexican Intercultural Context

2016 ◽  
Vol 11 (7) ◽  
pp. 120
Author(s):  
Marco Alberto Nunez Ramirez ◽  
Teodoro Rafael Wendlandt Amezaga ◽  
Maria Trinidad Alvarez Medina ◽  
Jorge Ortega Arreola
Keyword(s):  
Higher Education ◽  
College Students ◽  
Data Analysis ◽  
Empirical Evidence ◽  
Sampling Method ◽  
Educational Programs ◽  
Sustainable Rural Development ◽  
Indigenous Students ◽  
Entrepreneurial Skills ◽  
The One

The purpose of this study is to describe the development of entrepreneurial skills of college students in the intercultural context of Mexico. By a non-probability sampling method, a sample of 120 students from an intercultural institution of higher education in the Southeastern Mexico was selected, from which two groups (<em>Indigenous</em> and <em>Mestizos</em>) were obtained to perform the corresponding statistical analyses. The first group was integrated by indigenous students (<em>n </em>= 55) and the second group by mestizos (<em>n </em>= 65). For data analysis, the Student <em>t </em>test and one-way analysis of variance (ANOVA) were used. The results showed no significant differences in the entrepreneurial skills between both groups. However, significant differences were obtained when considering the educational programs offered by the intercultural institution, where the program in sustainable rural development was the one that obtained a higher level regarding the development of entrepreneurial skills. This research contributes with empirical evidence to the knowledge on interculturality in this country.

scholarly journals Resiliensi Keluarga yang Memiliki Anak Tunagrahita: Bagaimana Peran Koherensi Keluarga?

2020 ◽  
Vol 8 (1) ◽  
pp. 101-111
Author(s):  
Alifah Nuke Febrianty ◽  
Alabanyo Brebahama ◽  
Melok Roro Kinanthi
Keyword(s):  
Intellectual Disability ◽  
Sense Of Coherence ◽  
Daily Living ◽  
Sampling Method ◽  
Family Resilience ◽  
Purposive Sampling ◽  
Regression Test ◽  
Positive Perspective ◽  
The One

Tunagrahita merupakan salah satu jenis disabilitas yang membuat penyandangnya memiliki inteligensi jauh di bawah rata-rata serta kemampuan bina bantu diri yang terbatas. Hambatan tersebut membuat anak tunagrahita menjadi kurang mandiri sehingga orang tua harus memberikan perhatian serta bantuan yang lebih besar dibandingkan dengan anak pada umumnya. Hal inilah yang dapat menjadi stressor bagi keluarga terutama ibu yang merupakan caregiver utama pada anak karena ibulah yang paling banyak meluangkan waktu untuk pengasuhan sang anak. Oleh karena itu dibutuhkan ketangguhan keluarga dalam menghadapi masalah terkait kehadiran anak tunagrahita. Resiliensi keluarga dianggap sukses bila keluarga dapat bertahan dari kesulitan dan mengambil makna dari kesulitan yang dihadapi. Salah satu cara untuk dapat resilien adalah dengan mengembangkan pandangan positif saat menghadapi masalah yang disebut juga sebagai koherensi keluarga. Penelitian ini bertujuan untuk mengetahui sejauh mana peran koherensi keluarga terhadap resiliensi keluarga yang memiliki anak tunagrahita dari perspektif ibu. Partisipan pada penelitian ini sebanyak 60 orang ibu yang memiliki anak tunagrahita, berdomisili di wilayah Jakarta, Bogor, Depok, Tangerang, dan Bekasi yang dipilih menggunakan metode  purposive sampling ­. Alat ukur yang digunakan yaitu Walsh Family Resilience Questionnaire (WFRQ) untuk mengukur resiliensi keluarga dan Family Sense of Coherence Scale (FSOCS) untuk mengukur family sense of coherence. Berdasarkan hasil uji regresi, didapatkan hasil bahwa family sense of coherence berperan secara signifikan (p 0,05) terhadap resiliensi keluarga (R-square= 0,235). Hal ini berarti koherensi keluarga berperan sebesar 23,5% terhadap resiliensi keluarga dan 76,5% lainnya dipengaruhi oleh faktor lain. Terkait dengan hal ini, upaya meningkatkan resiliensi keluarga dapat dilakukan dengan membantu keluarga mengembangkan perspektif positif dalam melihat situasi yang terjadi, menumbuhkan optimisme, dan mengedukasi keluarga untuk dapat memanfaatkan sumber daya di sekitarnya untuk membantu atasi situasi. Intellectual disability is the one of disability in which the individu has intellectual far below the average, and limitation in activity daily living. This limitation makes the children with intellectual disability have low autonomy cause parents should give care and assitaant more then usual. This condition can be the one of stressor for family, especially for the mother as caregiver who give more time to practice parenting for their children. So, family resillience is very important to face the emergence of intellectual disability children in family. In order to be resillient, a family should have positive perspective when facing the problem, called sense of coherence. The purpose of this research is finding the role of family sense of coherence towards family resillience among family who has intellectual disability children. The participant of this research is 60 mothers who have intellectual disability children and live in Jakarta, Bogor, Depok, Tangerang, and Bekasi (Jabodetabek). The participants is selected by using purposive sampling method. This research uesd Family Resilience Questionnaire (WFRQ) to measure family resillience, and Family Sense of Coherence Scale (FSOCS) to measure family sense of corerence. Based on regression test, family sense of corerence has significant role towards family resilience (R Square = 0,235, p 0,05). It meanse that family sense of coherence gives contribution about 23,5 % to family resillience, and 76,5 % influenced by another factors. As the conslusion, family can be more resillient if it develops positive perspective when facing problem, build optimism, and use every resources wisely in order to solve problem. 

PEST MANAGEMENT OF DOUGLAS-FIR TUSSOCK MOTH (LEPIDOPTERA: LYMANTRIIDAE): A SEQUENTIAL SAMPLING METHOD TO DETERMINE EGG MASS DENSITY

1984 ◽  
Vol 116 (7) ◽  
pp. 1041-1049 ◽  
Author(s):  
R. F. Shepherd ◽  
I. S. Otvos ◽  
R. J. Chorney
Keyword(s):  
Sampling Method ◽  
Mass Density ◽  
Sequential Sampling ◽  
Douglas Fir ◽  
Egg Mass ◽  
Tussock Moth ◽  
Incipient Stage ◽  
Orgyia Pseudotsugata ◽  
Detection Tool ◽  
Variability Data

AbstractA sequential egg-mass sample system for Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough (Lepidoptera: Lymantriidae), was designed, based on visual scanning of the lower branches of Douglas-fir trees, Pseudotsuga menziesii (Mirb.) Franco. A branch was removed from each quadrant from the upper, middle and lower crown level, and from the lowest whorl of a total of 59 non-defoliated trees in 10 areas. No consistent trend in egg-mass density per branch could be found between crown levels and no level proved superior as a representative of the tree. Therefore, the lower whorl of branches was selected for survey purposes because of sampling efficiency. Sample stop lines were determined from egg-mass density and variability data collected on 55 sites and subsequent defoliation estimates were related to these densities. The system is designed as an early detection tool to be used only in non-defoliated stands at the incipient stage of an impending outbreak.

Robust Design by Matching the Design With Manufacturing Variation Patterns

1994 ◽  
Author(s):  
Jyh-Cheng Yu ◽  
Kosuke Ishii
Keyword(s):  
Robust Optimization ◽  
Robust Design ◽  
Optimization Procedure ◽  
Theoretical Development ◽  
Future Application ◽  
Design Variables ◽  
Performance Variation ◽  
Heat Treated ◽  
Variation Patterns ◽  
Manufacturing Variation

Abstract This paper deals with robust design problems in which variations on design variables have significant correlation. Manufacturing errors often affect design variables with characteristic patterns, that is, the variations are coupled. Robust optimization seeks designs with optimal and robust performance. Designers should match the design to the Manufacturing Variation Patterns (MVP) in the constrained robust optimization procedure. This study focuses on matching the variation patterns found in typical manufacturing processes. It uses quadrature experimental design to approximate the performance variation within the patterns. We redefine the robust constraint activity for designs using MVP and propose our procedure to search for the robust feasible designs. Theoretical development of manufacturing variation matching leads to our case study of heat treated shaft design with minimum dimensional distortion. The paper also outlines our future application in injection molding gear design and challenge in the identification of nonlinear correlated MVP.

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