• Title/Summary/Keyword: iterative methodology

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A Research into the Characteristics of Fashion/Textile Design Practice-Led PhD Theses in the UK (영국의 패션, 텍스타일 디자인 실기 주도(Practice-led) 박사 논문에 관한 특성 연구)

  • Kim, Hye Eun
    • Journal of the Korean Society of Costume
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    • v.65 no.6
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    • pp.48-62
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    • 2015
  • Practice is essential in art and design. Through practice, artists gain tacit knowledge that is hard to acquire from conventional academic studies. This paper characterizes practice-led research in the study of fashion and textile design through the investigation of practice-led research theses in the UK. According to relevant literature, which includes four exemplary case studies, the following features can be drawn: First, the methodology is different in each case and the use of practice is unconventional. Second, the research is not always aimed at making products. Third, the structure follows an iterative process. Fourth, the ratios of theory and practice are different and various theories are used. Fifth, a personal journal or diary is used for reflection as a major aid to research. Lastly, the process should be recorded by a thorough academic method. Practice-led research can have unexpected outcomes in theory and practice. It can be a good option for fashion practice research to develop a better evaluation method and reduce the gap between subjectivity and objectivity.

A Study on the Dimension of Quality Metrics for Information Systems Development and Success : An Application of Information Processing Theory

  • An, Joon M.
    • The Journal of Information Technology and Database
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    • v.3 no.2
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    • pp.97-118
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    • 1996
  • Information systems quality engineering is one of the most problematic areas in practice and research, and needs cooperative efforts between practice and theory [Glass, 1996]. A model for evaluating the quality of system development process and ensuing success is proposed based on information processing theory of project unit design. A nomological net among a set of quality variables is identified from prior research in the areas of organization science, software engineering, and management information systems. More specifically, system development success was modelled as a function of project complexity, system development modelling environment, user participation, project unit structure, resource availability, and the level of iterative nature of development methodology. Based on the model developed from the information processing theory of project unit design in organization science. appropriate quality metrics for each variable in the proposed model are matched. In this way, a framework of relevant systems development and success quality metrics for controlling systems development processes and ensuing success is proposed. The causal relationships among the constructs in the proposed model are proposed as future empirical research for academicians and as managerial tools for quality managers. The framework and propositions help quality manager to select more parsimonious quality metrics for controlling information systems development processes and project success in an integrated way. Also this model can be utilized for evaluating software quality assurance programmes, which are developed and marketed by many vendors.

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End-mill Modeling and Manufacturing Methodology via Cutting Simulation (Cutting Simulation을 이용한 End-milling Cutter의 모델링 및 제작에 관한 연구)

  • Kim Jae-Hyun;Kim Jong-Han;Ko Tae-Jo;Park Jung-Whan
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.6 s.183
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    • pp.151-159
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    • 2006
  • This paper describes a design process of end-milling cutters: solid model of the designed cutter is constructed along with computation of cutter geometry, and the wheel geometry as well as wheel positioning data f3r fabricating end-mills with required cutter geometry is calculated. In the process, the main idea is to use the cutting simulation method by which the machined shape of an end-milling cutter is obtained via Boolean operation between a given grinding wheel and a cylindrical workpiece (raw stock). Major design parameters of a cutter such as rake angle, inner radius can be verified by interrogating the section profile of its solid model. We studied relations between various dimensional parameters and proposed an iterative approach to obtain the required geometry of a grinding wheel and the CL data for machining an end-milling cutter satisfying the design parameters. This research has been implemented on a commercial CAD system by use of the API function programming, and is currently used by a tool maker in Korea. It can eliminate producing a physical prototype during the design stage, and it can be used for virtual cutting test and analysis as well.

A study on the improvement method of the stress field analysis in a domain composed of dissimilar materials (이종재료로 구성된 영역의 응력장 해석 개선방안 연구)

  • Song, Kee-Nam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.11
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    • pp.1844-1851
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    • 1997
  • Displacement fields and interface stresses are obtained by modifying the potential energy functional with a penalty function which enforces the continuity of stresses at the interface of two-materials. Based on the displacement field and the interface stresses, a new methodology to generate a continuous stress field over the entire domain including the interface of the dissimilar materials has been proposed by combining the L$^{2}$ projection method of stress-smoothing and the Loubignac's iterative method of improving the displacement field. Stress analysis was carried out on two examples which are made of highly dissimilar materials. As a result of the analysis, it is found that the proposed method provides improved continuity of the stress field over the entire domain as well as predicting accurate nodal stresses at the interface. In contrast, the conventional displacement-based finite element method provides significant stress discontinuties at the interfaces. In addition, it was found that the total strain energy evaluated from the improved continuous stress field converge to the exact value as increasing the number of iterations in the proposed method.

Bid-based Direct Load Control Framework Under Electricity Markets (전력시장 환경하에 입찰기반의 직접부하제어 운영방안)

  • Lee, Ho-Chul;Song, Sung-Hwan;Yoon, Yong-Tae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.3
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    • pp.455-461
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    • 2009
  • This paper proposes Direct Load Control(DLC) operation scheme using a bidding system and the methodology to value proper quantity decided by the DLC program, which is a kind of resources for stabilization of electricity market price during peak times by managing consumer electricity demand. Since DLC program in Korea is based on the contract with the customers participating in this program, it is difficult to anticipate voluntary participation. That is, incentive for participants in DLC program is insufficient. To cope with this point, it is necessary to develop a new market mechanism and market compatible operation scheme for DLC programs. DLC market mechanism is deemed to be equipped with iterative bidding system, independent operation from energy market, and interactive with bidding information on energy market. With this market mechanism, it is important to find the optimal operation point of DLC allowing for the factors of stabilizing the electricity market price and compensating DLC implementation. This paper focuses on the mathematical approaches for the bid-based DLC operation scheme and examines several scenarios for the following technical justifications: 1) stabilization of electricity market price during peak times, 2) elasticity of demand.

Structural Design for Vibration Reduction in Brushless DC Stator

  • Jafarboland, Mehrdad;Farahabadi, Hossein Bagherian
    • Journal of Electrical Engineering and Technology
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    • v.12 no.5
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    • pp.1842-1850
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    • 2017
  • Reducing the noise and vibration of the BLDC motors is very essential for some special applications. In this paper, a new structural design is introduced to increase the natural frequencies of the stator in BLDC motors as increasing the natural frequencies can reduce the severe effects of the structural resonances, including high levels of noise and vibration. The design is based on placing a single hole on definite regions at the stator cross sectional area (each region contains one tooth and its upper parts in the stator yoke) in an optimum way by which the natural frequencies at different modes are shifted to the higher values. The optimum diameter and locations for the holes are extracted by the Response Surface Methodology (RSM) and the modal analyses in the iterative process are done by Finite Element Method (FEM). Moreover, the motor performance by the optimum stator structure is analyzed by FEM and compared with the prototype motor. Preventing the stator magnetic saturation and the motor cogging torque enhancement are the two constraints of the optimization problem. The optimal structural design method is applied experimentally and the validity of the design method is confirmed by the simulated and experimental results.

Multi-Physics Simulations of Fluidelastic Instability for Tube Bundles in Cross-Flow (유체-구조 상호작용을 적용한 튜브다발의 유체탄성불안정성 과도적 전산해석)

  • Lee, Min-Hyung;Kim, Yong-Chan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.2
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    • pp.174-180
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    • 2004
  • Failure of tube bundles due to excessive flow-induced vibrations continues to affect the performance of nuclear power plant Early experimental studies concentrated on rigid structures and later investigators dealt with elastic structures because of their importance in many engineering fields. On the other hand, much less numerical work has been carried out, because of the numerical complexity associated with the problem. Conventional approaches usually decoupled the flow solution from the structural problem. The present numerical study proposes the methodology in analyzing the fluidelastic instability occurring in tube bundles by coupling the Computational fluid Dynamics (C%) with the tube equation of motions. The motion of the structures is modeled by a spring-damper-mass system that allows transnational motion in two directions (a two-degree-of-freedom system). The fluid motion and the cylinder response are solved in an iterative way, so that the interaction between the fluid and the structure can be accounted for property. The aim of the present work is to predict the fluidelstic instability of tube bundles and the associated phenomena, such as the response of the cylinder, the unsteady lift and drag on the cylinder, the vortex shedding frequency.

Nonlinear interaction analysis of infilled frame-foundation beam-homogeneous soil system

  • Hora, M.S.
    • Coupled systems mechanics
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    • v.3 no.3
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    • pp.267-289
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    • 2014
  • A proper physical modeling of infilled building frame-foundation beam-soil mass interaction system is needed to predict more realistic and accurate structural behavior under static vertical loading. This is achieved via finite element method considering the superstructure, foundation and soil mass as a single integral compatible structural unit. The physical modelling is achieved via use of finite element method, which requires the use of variety of isoparametric elements with different degrees of freedom. The unbounded domain of the soil mass has been discretized with coupled finite-infinite elements to achieve computational economy. The nonlinearity of soil mass plays an important role in the redistribution of forces in the superstructure. The nonlinear behaviour of the soil mass is modeled using hyperbolic model. The incremental-iterative nonlinear solution algorithm has been adopted for carrying out the nonlinear elastic interaction analysis of a two-bay two-storey infilled building frame. The frame and the infill have been considered to behave in linear elastic manner, whereas the subsoil in nonlinear elastic manner. In this paper, the computational methodology adopted for nonlinear soil-structure interaction analysis of infilled frame-foundation-soil system has been presented.

Interactive 3D Pattern Design Using Real-time Pattern Deformation and Relative Human Body Coordinate System (실시간 패턴 변형과 인체 상대좌표계를 이용한 대화형 3D 패턴 디자인)

  • Sul, In-Hwan;Han, Hyun-Sook;Nam, Yun-Ja;Park, Chang-Kyu
    • Fashion & Textile Research Journal
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    • v.12 no.5
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    • pp.582-590
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    • 2010
  • Garment design needs an iterative manipulation of 2D patterns to generate a final sloper. Traditionally there have been two kinds of design methodologies such as the flat pattern method and the pattern draping method. But today, it is possible to combine the advantages from the two methods due to the realistic cloth simulation techniques. We devised a new garment design system which starts from 3D initial drape simulation result and then modifies the garment by editing the 2D flat patterns synchronously. With this interactive methodology using real-time pattern deformation technique, the designer can freely change a pattern shape by watching its 3D outlook in real-time. Also the final garment data were given relative coordinates with respect to the human anthropometric feature points detected by an automatic body feature detection algorithm. Using the relative human body coordinate system, the final garments can be re-used to an arbitrary body data without repositioning in the drape simulation. A female shirt was used for an example and a 3D body scan data was used for an illustration of the feature point detection algorithm.

A Study of Machining Error Compensation for Tool Deflection in Side-Cutting Processes using Micro End-mill (측면가공에서 마이크로 엔드밀의 공구변형에 의한 절삭가공오차 보상에 관한 연구)

  • Jeon, Du-Seong;Seo, Tae-Il;Yoon, Gil-Sang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.128-134
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    • 2008
  • This paper presents a machining error compensation methodology due to deflection of micro cutting tools in side cutting processes. Generally in order to compensate for tool deflection errors it is necessary to carry out a series of simulations, cutting force prediction, tool deflection estimation and compensation method. These can induce numerous calculations and expensive costs. This study proposes an improved approach which can compensate for machining errors without simulation processes concerning prediction of cutting force and tool deflection. Based on SEM images of test cutting specimens, polynomial relationships between machining errors and corrected tool positions were induced. Taking into account changes of cutting conditions caused by tool position variation, an iterative algorithm was applied in order to determine corrected tool position. Experimental works were carried out to validate the proposed approach. Comparing machining errors of nominal cutting with those of compensated cutting, overall machining errors could be remarkably reduced.