• 한국기계가공학회지
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• 제8권3호
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• pp.27-32
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• 2009

In this study, static and dynamic stability estimations on the diecutter with finite element modelling were carried out to be creased and cut away printed sheet exactly. To cut away the sheet exactly, the large force should be pressured on diecutter. And which affects not only the quality of produced sheets but also the stability of diecutter. The analyses with and without the tare of diecutter were carried out with NASTRAN software on applying 400 ton force to its top and moving table respectively. It was known that maximum von-Mises stress of 221 Mpa in diecutter was occurred at the toggle, and it was smaller than the yield stress of 280 Mpa. And maximum deformation of 0.75 mm was occurred at the top table. The natural frequencies of 41, 102, 108, 115, and 134 Hz for the 1st, 2nd, 3rd, 4th and 5th mode, which had been determined by numerical simulation, were not coincided with the max. speeds of motor and moving table of 29 and 2 Hz. And which was verified by vibration test. Therefore it may be estimated that the structure of the diecutter is statically and dynamically stable.

• 복식
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• 제57권7호
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• pp.1-14
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• 2007

This study investigates the differences between the satisfaction factors of store characteristics depending on on-line clothing store type and its satisfaction index. The collected data were analyzed by using SPSS 10.0 software with various techniques such as paired t-test, T-test, Cronbach's ${\alpha}$ reliability and factor analysis that use principal component analysis and Varimax orthogonal rotation were used. The results are summarized as follows: 1. By categorizing the level of on-line store characteristics satisfaction depending on its type, clarifies the differences between its satisfaction. The satisfaction rank of general merchandise store was as followed: searching and approaching system, buying process service, screen-displayed design, product, store credit. On the other hand, the satisfaction rank of general store was as followed: screen-displayed design, store credit, buying process service. 2. By analyzing the difference of satisfaction depending on the store type, it was found that general merchandise store was more satisfied with screen-displayed design, approaching and searching, whole payment process, the safety of payment and shipping service, security service when compared to specialty store. It was also found that specialty store was more satisfied with the variety of product, update of rare items, quality and price of product. 3. By analyzing the difference between the type of on-line clothing store satisfaction depending on age, in the case of general merchandise store, the result showed that people in their thirties were more satisfied with buying process service, store credit, customer management system when compared to twenties. In the case of specialty store, the result showed that people in their twenties were more satisfied with customer management service when compared to thirties, and when it came to buying process service, it was vice versa.

• Journal of Biosystems Engineering
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• 제43권3호
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• pp.229-236
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• 2018

Purpose: Makgeolli is a traditional alcoholic beverage made from rice with a fermentation starter called "nuruk." The concentration of alcohol in makgeolli depends on the temperature of the fermentation tank. It is important to monitor the alcohol concentration to manage the makgeolli production process. Methods: Data were collected from 84 makgeolli fermentation tanks over a year period. Independent variables included the temperatures of the tanks and the room where the tanks were located, as well as the quantity, acidity, and water concentration of the source. Software for the multilayer perceptron model (MLP) was written in Python using the Scikit-learn library. Results: Many models were created for which the optimization converged within 100 iterations, and their coefficients of determination $R^2$ were considerably high. The coefficient of determination $R^2$ of the best model with the training set and the test set were 0.94 and 0.93, respectively. The fact that the difference between them was very small indicated that the model was not overfitted. The maximum and minimum error was approximately 2% and the total MSE was 0.078%. Conclusions: The MLP model could help predict the alcohol concentration and to control the production process of makgeolli. In future research, the optimization of the production process will be studied based on the model.

• 한국산학기술학회논문지
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• 제5권5호
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• pp.442-446
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• 2004

스웨이징(swaging)제조 공정의 컴퓨터 시뮬레이션에 관한 연구를 수행하기 위하여 상용 소프트웨어를 사용하였다. 시행오차를 통하여 획득한 경험에 기반을 두어 튜브 스웨이징 공정의 시뮬레이션이 이루어졌으며, 변형 경화 지수(strain hardening exponent) n과 소성계수(plastic modulus) K는 튜브재료의 실제 인장 측정 시험을 통하여 얻어졌다. 두 종류의 서로 다른 다이와 튜브 형상을 사용하여 비교하였다. 전처리는 HyperMesh(r), 해석은 LS-DYNA(r), 후처리는 LS-TAURUS(r)를의 상용 소프트웨어를 사용하였으며, 본 연구에서 얻어진 결과들을 문헌에서 이용 가능한 결과들과 비교하였다.

• 한국항공우주학회지
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• 제30권7호
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• pp.1-10
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• 2002

설계 순기의 단축, 개발 비용의 절감, 제품 성능의 향상을 목적으로 하는 MDO(Multidisciplinary Design Optimization)의 적용이 가능한 프레임워크의 개발을 위하여 해석 자원의 통합 방안, 해석 및 최적화 과정의 관리 방안과 이를 위한 소프트웨어 구조를 제시하였다. 중앙집중식 DBMS(Data Base Management System)을 채택하였으며, 해석 코드의 통합 방안으로 DLL(Dynamic Link Library)을 이용하는 방법과 입출력 파일을 이용하는 방안을 제시하였다. 해석 및 최적화 과정과 데이터 흐름을 관리하는 방안으로 Graphic Programming의 개념을 도입하였다. 간단한 수치 예제와 삼차원 패널 코드를 이용한 항공기 날개의 형상 최적화에 적용하여 제시한 방안의 타당성을 검증하였다.

• International Journal of Contents
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• 제11권1호
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• pp.41-51
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• 2015

Management systems for electronic library have been developed on the basis of Client/Server or ASP framework in domestic market for a long time. Therefore, both service provider and user suffer from their high cost and effort in management, maintenance, and repairing of software as well as hardware. Recently in addition, mobile devices like smartphone and tablet PC are frequently used as terminal devices to access computers through the Internet or other networks, sophisticatedly customized or personalized interface for n-screen service became more important issue these days. In this paper, we propose a new scheme of integrated management system for electronic library based on SaaS and Web Standard. We design and implement the proposed scheme applying Electronic Cabinet Guidelines for Web Standard and Universal Code System. Hosted application management style and software on demand style service models based on SaaS are basically applied to develop the management system. Moreover, a newly improved concept of duplication check algorithm in a hierarchical evaluation process is presented and a personalized interface based on web standard is applied to implement the system. Algorithms of duplication check for journal, volume/number, and paper are hierarchically presented with their logic flows. Total framework of our development obeys the standard feature of Electronic Cabinet Guidelines offered by Korea government so that we can accomplish standard of application software, quality improvement of total software, and reusability extension. Scope of our development includes core services of library automation system such as acquisition, list-up, loan-and-return, and their related services. We focus on interoperation compatibility between elementary sub-systems throughout complex network and structural features. Reanalyzing and standardizing each part of the system under the concept on the cloud of service, we construct an integrated development environment for generating, test, operation, and maintenance. Finally, performance analyses are performed about resource usability of server, memory amount used, and response time of server etc. As a result of measurements fulfilled over 5 times at different test points and using different data, the average response time is about 62.9 seconds for 100 clients, which takes about 0.629 seconds per client on the average. We can expect this result makes it possible to operate the system in real-time level proof. Resource usability and memory occupation are also good and moderate comparing to the conventional systems. As total verification tests, we present a simple proof to obey Electronic Cabinet Guidelines and a record of TTA authentication test for topics about SaaS maturity, performance, and application program features.

• 한국시뮬레이션학회논문지
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• 제24권4호
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• pp.35-41
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• 2015

자동포용 주퇴복좌장치는 사격충격을 흡수하기 위한 목적으로 개발된 장치이다. 만약 자동포에서 탄자가 발사 될 때 발생하는 매우 높은 수준의 사격충격을 흡수하지 못한다면 반동에 의하여 정밀한 타격은 불가능해진다. 본 연구에서는 이러한 역할을 하는 주퇴복좌장치의 해석모델을 멀티도메인 소프트웨어를 활용하여 개발하고 검증하는 것을 다룬다. 연구의 진행과정은 다음과 같다. 우선 설계의도를 파악하여 해석모델을 개발하고 기본적인 감쇠특성을 확인한다. 그리고 필드테스트에서 얻은 사격충격력을 해석모델에 부여하여 필드테스트와 동일한 환경을 해석도구 상에 구축한다. 최종적으로 주퇴복좌장치의 내부압력과 포신의 변위를 필드테스트 결과와 비교하여 멀티도메인 소프트웨어를 활용한 주퇴복좌장치의 해석모델이 유효성을 갖는지를 검증한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.269-274
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• 2001

This research covers the development of new technique for composite injection molding of high stiffness Sabot. An analysis of polymer resin is performed by means of making test specimen mold and doing test with accordance of ASTM test guidelines. Structural analysis and simulation of injection molding process are carried out in order not only to estimate but also to predict the characteristics of molding stresses what both product and structure of mold may have. For structural analysis software, Moldflow and LS-dyna are used and universal test machine is utilized for evaluating performance of sabot. Cases of adopting this material to sabot are not announced yet in domestic academic world. In addition to that, materials for polymer-metal mixed injection molding are imported on the whole due to deficient level of domestic technology. Therefore, this new developed injection molding technique using PEI material can make it available to ensure the technology of making mold, injection and design. Finally, this technique may be applicable to another sabot having different radius of warheads from now on.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.295-298
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• 2005

This paper is concerned with the precision material property measurement of a micro metal thin foil that is used in MEMS technology. Since these MEMS components require great precision and accuracy, evaluation of reliability such as the lift cycle endurance test, impact test, and residual stress test is necessary for these components. However, in practice, real reliability tests are not easy to perform due to consideration of various factors. Rather than actual testing, it would be much easier to evaluate the reliability of components by the analytical approach. Although the analytical method is utilized by software tools, it is obviously necessary to acquire fundamental properties of materials through real test methods. In this paper, the oriented mechanical properties of aluminum thin foil are measured by nano scale material property measurement system.

• 한국정보전자통신기술학회논문지
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• 제9권3호
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• pp.278-284
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• 2016

소프트웨어 개발과정에서 소프트웨어 신뢰성은 매우 중요한 이슈이다. 소프트웨어 고장분석을 위한 무한고장 비동질적인 포아송과정에서 고장발생률이 상수이거나, 단조 증가 또는 단조 감소하는 패턴을 가질 수 있다. 본 논문에서는 수리시점에서도 고장이 발생할 상황을 반영하는 무한고장 NHPP모형들을 비교 제시하였다. 소프트웨어 경제, 경영, 보험수리분야에서 많이 사용되는 선형 위험률분포의 절편모수에 근거한 무한고장 소프트웨어 신뢰성모형에 대한 비교문제를 제시하였다. 그 결과 절편모수가 비교적 큰 경우가 효율적으로 나타났다. 그리고 모수 추정법은 최우추정법을 이용하였고 모형선택은 평균제곱오차와 결정계수를 이용하였다. 본 연구에서 제안된 방법은 선형 위험률분포의 절편모수를 고려한 모형도 신뢰성 측면에서 효율적이기 때문에 (결정계수가 90% 이상) 이 분야에서 기존 모형의 하나의 대안으로 사용할 수 있음을 확인 할 수 있었다. 이 연구를 통하여 소프트웨어 개발자들은 다양한 수명분포의 절편모수를 고려함으로서 소프트웨어 고장형태에 대한 사전지식을 파악하는데 도움을 줄 수 있으리라 사료 된다.