• 한국주거학회논문집
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• 제13권6호
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• pp.89-99
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• 2002

The purpose of this research is to analyze the characteristics of flow rate distribution in hot-water piping networks in the apartment building. A 14-story apartment house was selected as a sample building and analyzed numerically by Hardy-Cross method. Two different piping networks, one has three vertical zones and the other of a single zone with automatic balancing valves, were compared. Some of research results are as follows; As the temperature of supply hot-water increases, the flow rate of it does by buoyancy effect, but this effect is not found in the piping network with automatic balancing valves. Non-uniformity in hot-water flow distributions to all stories in the piping system of single vertical zone can be completely reformed by the installation of either manually operated or automatic balancing valves in every story.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.199-202
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• 1997

We are developing computer integrated polysomnography system. This system integrates conventional polysomnography with computer for data management, automatic analysis, scoring, and data transmission. In the first stage, we have developed the signal interface and user interface for the manual scoring and data management. For the automatic scoring of sleep stage, we have developed the protocol and have applied the analytic method in its primitive form. In the second stage we will develope a partially automatic scoring system, and finalize the fully automatic system in the final third stage.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.314-320
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• 1998

Wear debris morphology is closely related to the wear mode and mechanism occured. Image recognition of wear debris is, therefore, a powerful tool in wear monitoring. But it has usually required expert's experience and the results could be too subjective. Development of automatic tools for wear debris recognition is needed to solve this problem. In this work, an algorithm for automatic wear debris recognition was suggested and implemented by PC base software. The presented method defined a characteristic 3-dimensional feature space where typical types of wear debris were separately located by the knowledge-based system and compared the similarity of object wear debris concerned. The 3-dimensional feature space was obtained from multiple feature vectors by using a multi-dimensional scaling technique. The results showed that the presented automatic wear debris recognition was satisfactory in many cases application.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1882-1887
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• 2002

This study is to develop a automatic design program of mechanical elements as the integrated system which can create automatically 3-dimensional solid and surface model using visualLISP. By the applying developed system to CAE system, the following objects are realized. At first, constructing the library of automatic design program for unexperienced design engineer, the 3-dimensional modeling of mechanical elements can be obtained easily. at second, the 3-dimensional model for ratchet wheel design is created by finete element model of CAE system and the optimal design condition of key way.

• Tribology and Lubricants
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• 제15권2호
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• pp.206-211
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• 1999

Wear debris morphology is closely related to the wear mode and mechanism occured. Image recognition of wear debris is, therefore, a powerful tool in wear monitoring. But it has usually required expert's experience and the results could be too subjective. Development of automatic tools for wear debris recognition is needed to solve this problem. In this work, an algorithm for automatic wear debris recognition was suggested and implemented by PC base software. The presented method defined a characteristic 3-dimensional feature space where typical types of wear debris were separately located by the knowledge-based system and compared the similarity of object wear debris concerned. The 3-dimensional feature space was obtained from multiple feature vectors by using a multi-dimensional scaling technique. The results showed that the presented automatic wear debris recognition was satisfactory in many cases application.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.359-369
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• 1999

The paper describes the study of concurrent subspace optimization(CSSO) for coupled multidisciplinary design optimization (MDO) techniques in mechanical systems. This method is a solution to large scale coupled multidisciplinary system, wherein the original problem is decomposed into a set of smaller, more tractable subproblems. Key elements in CSSO are consisted of global sensitivity equation(GSE), subspace optimization (SSO), optimum sensitivity analysis(OSA), and coordination optimization problem(COP) so as to inquiry valanced design solutions finally, Automatic differentiation has an ability to provide a robust sensitivity solution, and have shown the numerical numerical effectiveness over finite difference schemes wherein the perturbed step size in design variable is required. The present paper will develop the automatic differentiation based concurrent subspace optimization(AD-CSSO) in MDO. An automatic differentiation tool in FORTRAN(ADIFOR) will be employed to evaluate sensitivities. The use of exact function derivatives in GSE, OSA and COP makes Possible to enhance the numerical accuracy during the iterative design process. The paper discusses how much influence on final optimal design compared with traditional all-in-one approach, finite difference based CSSO and AD-CSSO applying coupled design variables.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1995년도 VTS and IBS 95 The Korean Institute of Navigation 1995년도
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• pp.153-165
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• 1995

When an automatic course-keeping is introduced as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit(or telemotor unit) steering gear ship dynamics and magnetic or gyro compass. We derive the mathematical model of each element of the automatic steering system. We provide a method of theoretical analysis on propulsive energy loss related to automatic steering of ships inthe open seas taking account of the on-off mechanism of power unit. Also we paid attention to dead band mechanism of autopilot device which is normally called weather adjustment. Next we make numerical calculation of the effects of autopilot control constants ont he propulsive energy loss for two kinds of ship a fishing boat and an ore carrier. Realistic sea and wind disturbances are employed in the calculation.

• 한국지리정보학회지
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• 제17권3호
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• pp.68-81
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• 2014

본 연구에서는 지점강우를 면적평균강우로 변환하는데 이용되는 DA(Depth-area)관계를 보다 효율적이고 정확하게 구축할 수 있는 자동 DAD분석기법을 국내의 유역에 적용하고 그 성능을 평가하는데 목적이 있다. 우선, 제안된 자동 DAD분석기법에는 격자기반의 공간강우분포를 호우중심으로부터 추적하는 방법으로 Box-tracking, Point-tracking, Advanced point-tracking으로 구분된다. 세 가지 방법을 용담댐 유역에서 발생한 호우 중 대표적인 10개의 호우사상에 대하여 적용한 결과, Advanced point-tracking을 적용하였을 경우가 다중호우중심을 가진 각 호우분포 형상을 정확히 고려하고, 보다 정확한 누적 시간별 누적 면적별 면적최대강우량(MAAR)을 산정할 수 있음을 확인하였다. 게다가, Advanced point-tracking이 선정된 여러 개의 호우중심으로부터 면적증가에 따른 각각의 MAAR을 동시에 산정하고 비교할 수 있어, 이에 따른 오차를 효과적으로 감소시킬 수 있음을 확인하였다. 마지막으로, 용담댐 유역의 10개의 호우사상에 대한 DAD 분석을 토대로 해당 유역의 DAD곡선을 누적시간별로 추출하였다.

• 소성∙가공
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• 제28권3호
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• pp.115-122
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• 2019

In this paper, finite element analysis of an automatic five-stage precision cold forging process of a yoke, a steering part of a passenger's car, is conducted with emphasis on spring back analysis at the yoke-forming stage and its experimental verification is subsequently made. An elastoplastic finite element method with MINI-element technique employed for the analysis of the entire process is explained. There is emphasis that the thin film of material formed between the punch and die in the stage may result to some errors especially in elastoplastic finite element analysis of spring back due to frequent remeshing. The numerical robustness of the spring back analysis in regards to remeshing is hence shown first through investigation into its effect on the predicted spring back. Experimental measurement of displacement due to spring back is carried out for comparison with the predicted results, and they are in a qualitative agreement with each other.

• 한국의류학회지
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• 제20권1호
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• pp.54-65
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• 1996

The purposes of this study were 1) to present the optimum slacks pattern for young men, 2) to develope a methodology to draft basic slacks pattern using AutoCAD The total crotch legth and the shape of the crutch line were determined by anthropometric data analysis. The total crotch length was calculated with the waist girth, the hip girth and the crotch length measurements. The anthropometric data utilized for this procedure was National Anthropometric Survey of Korea, 1992. And multidimensional anthropometric measurements were carried out for 6 male college students between the age of 18 to 24. The subjects were measured with the Martin's anthropometer and the sliding gauge. Mean, standard deviation and t-test were performed for statistical analysis of the data. The automatic drafting method was programmed by AutoLISP in AutoCAD. The automatic drafting was based on the Muller's slacks pattern drafting method, the measurements of slacks construction components and the curve of crotch line. The crotch line was drafted using of the arc function in AutoCAD. The total crotch length was calcuated using the multiple regression equation. The experimental pattern developed to accomodate individual body wleasurements expected to produce customized apparel production in QRS(Quick Response System) production system.