• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.283-292
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• 2013

This paper aims to propose a new steps of hypothesis testing using analysis process and improvement process in the six sigma DMAIC. The six sigma implementation models proposed in this paper consist of six steps. The first step is to establish a research hypothesis by specification directionality and FBP(Falsibility By Popper). The second step is to translate the research hypothesis such as RHAT(Research Hypothesis Absent Type) and RHPT(Research Hypothesis Present Type) into statistical hypothesis such as $H_0$(Null Hypothesis) and $H_1$(Alternative Hypothesis). The third step is to implement statistical hypothesis testing by PBC(Proof By Contradiction) and proper sample size. The fourth step is to interpret the result of statistical hypothesis test. The fifth step is to establish the best conditions of product and process conditions by experimental optimization and interval estimation. The sixth step is to draw a conclusion by considering practical significance and statistical significance. Important for both quality practitioners and academicians, case analysis on six sigma projects with implementation guidelines are provided.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.139-146
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• 2000

This paper presents a prototype for structural analysis and design system by use of the STEP concepts for the representation and exchange of information on framed steel structures, and also integrates the product model of steel structures of AP 230, geometric and topological information of Part 42, and detailed Finite Element Analysis information of Part 104 into an unified system. Thus, the STEP-based system makes engineering information more clearable and exchangeable between computer applications than any other conventional methods. This system may be further extended to incorporate other computer applications for detailed engineering and manufacturing information on steel structures.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.179-189
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• 2007

Every purchase a customer makes builds patterns about how products are purchased together. The process of finding these patterns, called market basket analysis, is composed of two steps in the Microsoft Association Algorithm. The first step is to find frequent item-sets. The second step which requires much less time than the first step does is to generate association rules based on frequent item-sets. Even though the first step, finding frequent item-sets, is the core part of market basket analysis, when applied to Online Analytical Processing(OLAP) cubes it always raises several points such as longitudinal analysis becomes impossible and many unpractical transactions are built up. In this paper, a new OLAP cube structures designing method which makes longitudinal analysis be possible and also makes only real customers' purchase patterns be identified is proposed for market basket analysis.

• Advances in aircraft and spacecraft science
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• v.5 no.3
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• pp.385-400
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• 2018

In this paper dynamic behavior (modal analysis and dynamic transient response) of a novel sandwich T-joint is numerically and experimentally investigated. An epoxy adhesive is selected for bonding purpose and making the step wise graded behavior of adhesive region. The effect of the step graded behavior of the adhesive zone on dynamic behavior of a sandwich T-joint is numerically studied. Finite element analysis (FEA) of the T-joints with carbon fiber reinforced polymer (CFRP) face-sheets is performed by ABAQUS 6.12-1 FEM code software. Modal analysis and dynamic half-sine transient response of the sandwich T-joint are presented in this paper. Two verification processes employed to verify the dynamic modeling of the manufactured sandwich panels and T-joint modeling. It has been shown that the step wise graded adhesive zone cases have changed the second natural frequency by about 5%. Also, it has been shown that the different arranges in the step wise graded adhesive zone significantly affect the maximum stresses due to transient dynamic loading by 1112% decrease in maximum peel stress and 691.9% decrease in maximum shear stress on the adhesive region.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.4
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• pp.43-50
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• 2006

The objective of this research is to select the most effective technique from AMT (Advanced Manufacturing Technologies) and IMP (Innovative Management Practices) for improving manufacturing performance in shipbuilding enterprises. The research consists of several principal steps. The first step is to design critical criteria in evaluating manufacturing performance in shipbuilding enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP (Analytic Hierarchy Process) structure using the critical criteria, sub-criteria and techniques from AMT and IMP. The fourth step is to develope the pairwise comparison matrix by each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique from AMT and IMP by using AHP analysis. The results of AHP analysis did not show clear difference in priority between techniques of AMT and IMP in terms of manufacturing performance of the shipbuilding enterprise. Thus, each critical criterion was assigned modified weights and examined the priority change of techniques by conducting performance sensitivity analysis.

• Journal of the Ergonomics Society of Korea
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• v.26 no.4
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• pp.103-111
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• 2007

The purpose of this study is to categorize and analyze the body shape of obese Korean men that are needed for industrial design. Using the anthropometric data that were surveyed through the 5^th Size Korea project, this study was conducted in four steps mostly through the multivariate statistical analysis. In the first step, Broca, BMI, WHR indices are used to define obesity and select obese men from Korean adults and teens. After 34 human anthropometric variables are supposed to be related to obesity were extracted through an expect survey. In the second step, a factor analysis was executed for those human anthropometric variables. Through this analysis, we obtained the human body factors that are related to the representation of obesity. Then the third step, we used a cluster analysis from the result of the factor analysis. And ANOVA analysis was also conducted to obtain the critical obese human anthropometric variables. In the final step, we found the characteristics of the body types of obese men according to clusters and ages. The body types of obese men classified in the study are expected to be applied to product design for clothing, furniture, automobile packaging, etc.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.1
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• pp.23-30
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• 2022

This study proposed a simplified finite element analysis procedure for designing the nonstructural masonry wall in the out-of-plane direction. The proposed method is a two-step elastic analysis procedure by bilinearizing the behavior of the masonry wall. The first step analysis was conducted with initial stiffness representing the behavior up to the effective-yield point, and the second step analysis was conducted with post-yield stiffness. In addition, the orthotropic material property of the masonry was considered in the FE analysis. The maximum load was estimated as the sum of the maximum loads in the first and second step analyses. The maximum load was converted into the moment coefficients and compared with those from the yield line method applied in Eurocode 6. The moment coefficients calculated through the proposed procedure showed a good match with those from the yield line method with less than 6% differences.

• Structural Engineering and Mechanics
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• v.45 no.4
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• pp.521-542
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• 2013

In this study a truss model is used for the geometrically nonlinear static and dynamic analysis of a thin shallow arch subject to snap-through. Thanks to the very simple geometry of a truss, the equilibrium conditions can be easily written and the global stiffness matrix can be easily updated with respect to the deformed structure, within each step of the analysis. A very coarse discretization is applied; so, in a very simple way, the high frequency modes are suppressed from the beginning and there is no need to develop a complicated reduced-order technique. Two short computer programs have been developed for the geometrically nonlinear static analysis by displacement control of a plane truss model of a structure as well as for its dynamic analysis by the step-by-step time integration algorithm of trapezoidal rule, combined with a predictor-corrector technique. These two short, fully documented computer programs are applied on the geometrically nonlinear static and dynamic analysis of a specific thin shallow arch subject to snap-through.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.130-135
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• 2003

This paper presents the method for structure borne noise analysis of a flexible body in multibody system. The proposed method is the superposition method using flexible muitibody dynamic analysis and finite element one. This method is executed in 3 steps. In the la step, time dependent quantities such as dynamic loads, modal coordinates ana gross body motion of the flexible body are calculated efficiently through flexible multibody dynamic analysis. And frequency response functions are computed using Fourier transforms of those time dependent quantities. In the 2$\^$nd/ step, acoustic pressure coefficients are obtained through structure-acoustic coupling analysis by finite element analysis. In the final step, frequency responses of acoustic pressure at the acoustic nodes are recovered through linear superposition of frequency response functions with acoustic pressure coefficients. The accuracy of the proposed method is verified in the numerical example of a simple car model.

• Korean Journal of Computational Design and Engineering
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• v.12 no.5
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• pp.366-375
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• 2007

Although the STEP modularization is the major development methodology for STEP Application Protocol, there have been few studies on the STEP Modularization in Korea. The necessity of STEP Modularization research has been raised continuously. In addition, the importance became larger and larger because most of newly developing APs, including AP241, are developed using modularization approach. The object of this study is to investigate the basic structure and contents of AEC facilities related Application Modules using STEP Modularization. This study examines 1) the technical analysis regarding STEP Modularization, 2) application modules development regarding civil engineering elements of AP241; Aec_faciliteis_classification", "Aec_civil_item", and "Aec_civil_componet", 3) the developed application modules verification, and 4) the implementation methodology suggestion for application modules and modular AP.