• Title/Summary/Keyword: Suitable Model

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Thermal Stress Analysis of a Fuel Cell Stack using an Orthotropic Material Model (복합재료 연료전지 스택의 열응력 해석)

  • Jeon Ji Hoon;Hwang Woonbong;Um Sukkee;Kim Soowhan;Lim Tae Won
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.206-209
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    • 2004
  • Mechanical behavior of a fuel stack was studied using an orthotropic material model. The fuel stack is essentially composed of a bipolar plate (BP), a gasket, an end plate, a membrane electrolyte assembly (MEA), and a gas diffusion layer (GDL). Each component is fastened with a suitable pressure. It is important to maintain a suitable contact pressure distribution of BP, because it influences the power efficiency of the fuel cell stack. When it is exposed to high temperature, its behavior must be stable. Hence, we performed stress analysis at high temperature as well as at room temperature. At high temperature, the contact pressure distribution becomes poor. Many patents have shown that using an elastomer can overcome this phenomena. Its effect was also studied. By using an elastomer, we found a good contact pressure distribution at high temperature as well as at room temperature.

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A Basic Study on the Geobag System for Urgent Restoration of the Collapsed Roadbed (강우로 유실된 철도노반 긴급복구를 위한 지오백시스템 개발 기초연구)

  • 조삼덕;황선근;이대영;이광우
    • Journal of the Korean Geotechnical Society
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    • v.19 no.2
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    • pp.255-265
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    • 2003
  • A series of laboratory tests were performed to evaluate engineering properties of geobag system which is used for urgent restoration of the collapsed roadbed. In this study, the suitable geobag size was proposed as 44cm wide and 66cm long, and the suitable filling ratio of geobag was also proposed as 80% through the static loading tests. Also a series of model tests were carried out to investigate the characteristics of the engineering behavior and the distribution of earth pressure of the geobag roadbed under static and dynamic loading.

The Analysis of life distribution for Light Source using degradation Tests of Luminous Flux (광속의 열화시험을 이용한 광원의 수명분포 분석)

  • Lee, S.H.;Shin, S.W.;Cho, M.R.;Hwang, M.K.;Yang, S.Y.
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.11a
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    • pp.161-165
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    • 2005
  • In this paper, we observed degradation characteristics of luminous flux for new light source. Because degradation tests can be a useful tool for assessing the reliability when few or even no failures are expected in a life tests. And we use a simple random coefficient degradation model to induce most suitable equation of degradation. As a result, exponential distribution and equation is best suitable model for new light source.

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A Study on the Establishment of Masterplanner Operating Model for Residents' Participation Regeneration Project in Old Settlements of Downtown Jeju (제주시 원도심 주민참여형 재생사업의 총괄계획가 운영 모델 수립에 관한 연구)

  • Yang, Gun;Yi, Sang-Ho;Baek, Seung-Heon
    • Journal of the Korean Institute of Rural Architecture
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    • v.17 no.3
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    • pp.37-44
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    • 2015
  • The purpose of this study is to find important factors for establishment of masterplanner operating model in residents' participation regeneration project suitable for small provincial city compared with Seoul city's which were already operated these days. The study showed the following results: 1) Conditions required for masterplanners are professional, regionality, sustainability, balance, independence. 2) Regionality and professionality can be guaranteed by expert-recommendation and perform manual suitable for character of project and regional conditions. 3) Conditions required for masterplanners are applied flexibly depending on the size and duration of project.

A Study on Determine CONWIP(Constant Work In Process) System Model in the Dynamic Environment (동적환경하에서의 CONWIP(Constant Work In Process) 시스템 모델설정에 관한 연구)

  • 송관배;박재현;강경식
    • Journal of the Korea Safety Management & Science
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    • v.5 no.4
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    • pp.209-217
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    • 2003
  • The traditional Kanban needs a lot of preconditions for fitting conditions of dynamic production processing environment. The traditional Kanban isn't suitable conditions of dynamic production processing environment. Therefore conditions of dynamic production processing environment is needed more stable system. This study is describe CONWIP system such as suitable in dynamic production processing environment. Most Pull system is a Kanban system than use Kanban cards or signal for production management and inventory control. The object of Kanban system is reducing inventory between shop-floor that can reduce inventiry cost. If the system reduce the number of Kanban cards would be reduce the working process WIP, can be reduced and can be found all potential problem of production between shop-floors. This study apply to CONWIP system model for Korean industrial companies.

SERVICE QUALITY EVALUATION INDICATORS FOR ASP-BASED PROJECT MANAGEMENT INFORMATION SYSTEM

  • Lee, Seul-Ki;Yu, Jung-Ho;Kim, Chang-Duk
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.1453-1462
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    • 2009
  • It is very important for performance of information system that we make an effort to raise user's satisfaction by continuously grasping user's requirement by evaluation of PMIS based on ASP service quality and reflecting this to information system. However, It is lack that developments of suitable evaluation index of PMIS based on ASP service quality. Hereupon, In this study, we propose the evaluation indicators. First, The evaluation area is classified by form the foundation of D & M IS Success Model (2003); system quality, information quality, service quality. Second, The detail evaluation item which include considerations which are gotten through investigation of the construction industry and PMIS based on ASP is grouping by form the foundation SERVQUAL which is a service quality evaluation tool proposed PZB(1988). It is suitable to evaluate PMIS based on ASP service quality in construction industry and able to evaluate various aspects.

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A MODEL OF RISK MANAGEMENT PLAN AND SYSTEM FOR THE CONSTRUCTION PHASE

  • Seon-Gyoo Kim;Chan-Jeong Park ;Moon-Serk Yang;Jin-Bong Kim ;Hyung-John Shin
    • International conference on construction engineering and project management
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    • 2005.10a
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    • pp.341-346
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    • 2005
  • After the IMF shock, some major construction companies in Korea have been motivated to avoid and mitigate various risk factors which could be critical and catastrophic events to corporate revenue and organization internally or externally. It means that they are trying to introduce and set up a risk management plan and system suitable to their organization and culture. L construction co. ltd. is one of major construction companies that have been searching methodologies or technologies to manage various risk factors surrounding corporate marketing and project operation. This paper presents an unique approach to develop a model of risk management plan and system suitable to L construction itself focused on the construction phase.

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Selecting Machine Learning Model Based on Natural Language Processing for Shanghanlun Diagnostic System Classification (자연어 처리 기반 『상한론(傷寒論)』 변병진단체계(辨病診斷體系) 분류를 위한 기계학습 모델 선정)

  • Young-Nam Kim
    • 대한상한금궤의학회지
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    • v.14 no.1
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    • pp.41-50
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    • 2022
  • Objective : The purpose of this study is to explore the most suitable machine learning model algorithm for Shanghanlun diagnostic system classification using natural language processing (NLP). Methods : A total of 201 data items were collected from 『Shanghanlun』 and 『Clinical Shanghanlun』, 'Taeyangbyeong-gyeolhyung' and 'Eumyangyeokchahunobokbyeong' were excluded to prevent oversampling or undersampling. Data were pretreated using a twitter Korean tokenizer and trained by logistic regression, ridge regression, lasso regression, naive bayes classifier, decision tree, and random forest algorithms. The accuracy of the models were compared. Results : As a result of machine learning, ridge regression and naive Bayes classifier showed an accuracy of 0.843, logistic regression and random forest showed an accuracy of 0.804, and decision tree showed an accuracy of 0.745, while lasso regression showed an accuracy of 0.608. Conclusions : Ridge regression and naive Bayes classifier are suitable NLP machine learning models for the Shanghanlun diagnostic system classification.

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Development of Bivalve Culture Management System based on GIS for Oyster Aquaculture in GeojeHansan Bay (거제한산만 굴 양식장에 대한 GIS 기반 어장관리시스템 개발)

  • Cho, Yoon-Sik;Hong, Sok-Jin;Kim, Hyung-Chul;Choi, Woo-Jeung;Lee, Won-Chan;Lee, Suk-Mo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.16 no.1
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    • pp.11-20
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    • 2010
  • Oyster production is playing an important role in domestic aquaculture, but facing some problems such as exports decrease, a slowdown in domestic demand and marine environmental deterioration. In order to obtain the suitable and sustainable oyster production, suitable sites selection is an important step in oyster aquaculture. This study was conducted to identify the suitable sites for lunging culture of oyster using Geographic Information System(GIS)-based multi-criteria evaluation methods. Most of the parameters were extracted by Inverse Distance Weighted(IDW) methods in GIS and eight parameters were grouped into two basic sub-models for oyster aquaculture, namely oyster growth sub-model(Sea Temperature, Salinity, Hydrodynamics, Chlorophyll-a) and environment sub-model(Bottom DO, TOC, Sediment AVS, Benthic Diversity). Suitability scores were ranked on a scale from 1(leased suitable) and 8(most suitable), and about 80.1% of the total potential area had the highest scores 5 and 6. These areas were shown to have the optimum condition for oyster culture in GeojeHansan Bay. This method to identify suitable sites for oyster culture may be used to develop bivalve culture management system for supporting a decision making.

A Study on Wildlife Habitat Suitability Modeling for Goral (Nemorhaedus caudatus raddeanus) in Seoraksan National Park (설악산 산양을 대상으로 한 야생동물 서식지 적합성 모형에 관한 연구)

  • Seo, Chang Wan;Choi, Tae Young;Choi, Yun Soo;Kim, Dong Young
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.11 no.3
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    • pp.28-38
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    • 2008
  • The purpose of this study are to compare existing presence-absence predictive models and to predict suitable habitat for Goral (Nemorhaedus caudatus raddeanus) that is an endangered and protected species in Seoraksan national park using the best model among existing predictive models. The methods of this study are as follows. First, 375 location data and 9 environmental data layers were implemented to build a model. Secondly, 4 existing presence-absence models : Generalized Linear Model (GLM), Generalized Addictive Model (GAM), Classification and Regression Tree (CART), and Artificial Neural Network (ANN) were tested to predict the Goal habitat. Thirdly, ROC (Receiver Operating Characteristic) and Kappa statistics were used to calculate a model performance. Lastly, we verified models and created habitat suitability maps. The ROC AUC (Area Under the Curve) and Kappa values were 0.697/0.266 (GLM), 0.729/0.313 (GAM), 0.776/0.453 (CART), and 0.858/0.559 (ANN). Therefore, ANN was selected as the best model among 4 models. The models showed that elevation, slope, and distance to stream were the significant factors for Goal habitat. The ratio of predicted area of ANN using a threshold was 31.29%, but the area decreased when human effect was considered. We need to investigate the difference of various models to build a suitable wildlife habitat model under a given condition.