• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 제5회 박판성형 SYMPOSIUM
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• pp.55-60
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• 2006

Draw-bead is applied to control the material flow in a stamping process and improve the product quality by controlling the draw-bead restraining force (DBRF). Actual die design depends mostly on the trial-and-error method without calculating the optimum DBRF. Die design with the predicted value of DBRF can be utilized at the tryout stage effectively reducing the cost of the product development. For the prediction of DBRF, a simulation-based prediction model of the circular draw-bead is developed using the Box-Behnken design with selected shape parameters such as the bead height, the shoulder radius and the sheet thickness. The value of DBRF obtained from each design case by analysis is approximated by a second order regression equation. This equation can be utilized to the calculation of the restraining force and the determination of the draw-bead shape as a prediction model. For the evaluation of the prediction model, the optimum design of DBRF in sheet metal forming is carried out using response surface methodology. The suitable type of the draw-bead is suggested based on the optimum values of DBRF. The prediction model of the circular draw-bead proposes the design method of the draw-bead shape. The present procedure provides a guideline in the tool design stage for sheet metal forming to reduce the cost of the product development.

• 대한토목학회논문집
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• 제29권3D호
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• pp.399-408
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• 2009

우리나라 건설사업은 점차 대형화되고 복잡화되는 가운데 예산 및 원가절감에 대한 압박도 점차 높아지고 있다. 이러한 가운데 정부와 공공발주기관들은 경제성 및 품질 향상에 부응하기 위한 발주자 주도의 원가관리기법인 '설계VE(Value Engineering)'을 도입하기 위해 노력해왔다. 국토해양부는 2000년 3월 건설기술관리법시행령을 통해 총공사비 500억원 이상의 1종 시설물 공사에 대하여 설계VE를 의무화하였고 2006년 1월부터는 총공사비 100억원 이상 공사로 그 대상을 확대하였다. 또한 정부는 '경영혁신기본법'과 '공공기관운영에관한법률' 제정을 통해 공공발주기관의 경영혁신 필요성을 제고하고 있어 설계VE의 도입 필요성은 더욱 증가하고 있다. 이에 본 연구는 공공발주기관의 설계VE 성공과 매우 밀접한 7개 부문 총 19개의 핵심성공요인(Critical Success Factors, CSFs)을 도출하고, 10개의 주요기능을 도출한 후 프로세스 모델링기법을 활용하여 공공발주기관의 개선된 설계VE 프로세스를 제시하였다. 연구에서 제시된 프로세스는 공공발주기관인 G사의 사례 연구를 통해 그 효과를 확인하였다. 본 연구결과는 설계VE를 이미 시행하고 있거나 새로 도입하고자 하는 정부, 지방자치단체 및 기타 공기업들이 보다 효과적인 설계VE 프로세스를 도입하는데 활용될 수 있을 것으로 기대된다.

• 환경영향평가
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• 제27권2호
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• pp.181-193
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• 2018

본 연구는 구상나무(Abies koreana) 분포지를 대상으로 AHP (Analytic Hierarchy Process)기법을 적용한 InVEST모델을 사용하여 서식처 질 분석과 탄소고정량 추정을 통한 경제적 가치 평가를 하였다. 구상나무는 국내 고유종으로 장차 국가의 생물 주권 확립에 따라 핵심요소로 작용하고 있음에 따라 구상나무의 보존을 위해 연구대상지를 구상나무의 분포지인 한라산, 지리산, 소백산국립공원으로 선정하였다. InVEST모델 선행연구에서 시사한 한계점인 국내 입력자료가 없어 해외문헌의 값을 차용하여 정확성이 떨어지는 부분을 보완하기 위해 AHP기법을 적용하여 입력자료로 하였으며, 시나리오 분석을 위해 1980, 1990, 2000년을 기준으로 모델링을 하였다. 결과는 한라산국립공원이 가장 큰 서식처 질의 변화양상을 보였으며, 1980년은 $0.96{\pm}0.14$, 1990년은 $0.97{\pm}0.14$, 2000년은 $0.94{\pm}0.17$로 감소하는 것으로 도출되었다. 소백산국립공원의 구상나무의 분포지인 아고산지대의 변화가 가장 큰 곳으로, 서식처 질은 0.98, 0.98, 0.97로 감소하였다. 연구대상지 중 지리산국립공원의 서식처 질은 0.98, 0.99, 0.99로 가장 잘 보존된 곳으로 도출되었다. 그리고 경제적 가치환산 결과, 한라산은 1,928만 달러 손실, 소백산은 803만 달러 손실로 추정되었다. 결과적으로 국내 고유종인 구상나무가 제공하는 생태계서비스의 서식처 질과 경제적 가치추정을 통해 정량적인 값을 도출하였다. 생태계서비스 모델로 특정지역의 서식처 질 분석을 통한 정성적인 변화와 경제적 가치 환산을 통한 정량적인 값의 제시가 가능함을 확인할 수 있었다. 생태계서비스의 가치를 평가를 통해 보존지역의 개발과 같은 외부요인으로부터의 변화예측을 통한 객관적인 평가로 지속가능한 자연자원의 이용과 생태계 보전을 증진하는 방향으로 유도할 수 있는 방안으로 적용이 가능하다고 사료된다.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.644-651
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on water quality such as turbidity, temperature, pH and alkalinity. However, the process of chemical reaction to improve water quality (e.g., turbidity) by chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts using Jar-test data. In this paper, a systematic control strategy is proposed to derive the optimum dosage of coagulant, PAC(Polymerized Aluminium Chloride), using Jar-test results. A neural network model is developed for coagulant dosing and purifying process by means of six input variables (turbidity, temperature, pH, alkalinity of raw water, PAC feed rate, turbidity in flocculation) and one output variable, while considering the relationships to the reaction of coagulation and flocculation. The model is utilized to derive the optimum coagulant dosage (in the sense of minimizing turbidity of water in flocculator). The ability of the proposed control scheme validated through the field test has proved to be of considerable practical value.

• 한국환경과학회지
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• 제6권6호
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• pp.563-578
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• 1997

The purpose of this study is to suggest the estimation model of' amenity environment' by Perceived Envionmental Quality Index(PEQI) model. A questionnaire survey was carried out for 연e study area of Taegu-Kyungbuk region. Sampling size was 838(427 of Taegu and 411 of Kyungbuk residents by stratified sampling of each region's(7 Gu for Tae-gu, 7 Cities 61 Gun far Kyungbuk) population. The survey was done during Sep. to Nov, of 1996. The suggested model was composed of four estimation categories and 16 Indicators. The four categories were 'Cleanness 61 Quietness', 'Naturalness & Harmony', 'Beauty 61 Comfort' and 'Environmental Conservation Efforts'. And each category has several individual Indicators. The weighted means of satisfaction were different by each region. Suseong-gu, Dalseogu, Joong-gu(Taegu), Bumcheon, Andong, and Cheondo(Kyungbuk) showed high enoronmental satisfaction, but Dong-gu. Seo-gu(taegu), Youngcheon, and Pohang(Kyungbuk) showed lower environmental satisfaction. By Analytic Hierarchy Process(AHP) of weighting values for each categorirs, 'Enoronmental Conservation Efforts' was estimated as the most Important(value of 0.367), and 'Naturalness 61 Harmony'(0. 242),'Clenness & guletness'(0.225), and 'Beauty & Comfort'(0.166) were Important respectively. Total PEQI's were estimated as 48.0 for Taegu, and 53.3 for Kyungbuk. PEQI's for each regions were between 46.2(Dong-gu) and 59.9(Kimcheon). The validity of the suggested model was verined by factor analysis. The four factors were identnied as the same categories and indicators. Finally, The LISREL+7 model was suggested as estimauon model of 'Amenity Environment' for Taegu-Kyungbuk region.

• 상하수도학회지
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• 제30권5호
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• pp.579-586
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• 2016

In many countries in order to manage corrosion of water treatment process, it is currently using Langelier index (LI). However, management of the Larson's ratio (LR) to compare corrosion management and LI which can be generated by the water treatment process is required. In this study, in order to ensure data LR, factors associated with the actual corrosion resistance of water treatment plant was measured. Using the measured data, the model equation can be estimated alkalinity, and using the statutory water quality data, LR and alkalinity is estimated. At comparison of the measured value and estimated value of alkalinity, it appeared in $R^2$ = 0.629, using the statutory water quality data and estimated alkalinity model, LR and alkalinity (Whole water treatment plants : 472) is estimated. Concentration of estimated alkalinity is 0.5 mg/L to 107.5 mg/L (average : 23.2 mg/L), and LR is 0.1 to 10 (average : 1.3). At tendency to corrosion of investigated LR, "No metal tendency" (>0.5) is 39 water treatment plants, 8.26 %, and "corrosion metal tendency" is 433 water treatment plants, 91.74%.

• 산업공학
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• 제16권spc호
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• pp.116-122
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• 2003

We analyze how much employees' work abilities and overall satisfaction on the job or corporate influence on the productivity and customer satisfaction in the service industry, which is characterized by simultaneity, heterogeneity, intangibility and etc. Employees always encounter customers in process of the service. So, the employees' attitudes and behaviors have direct influences on the service quality or satisfaction which customers perceive. Also, employees' satisfaction or work abilities can lead to increase or decrease the productivity. To grasp and demonstrate the cause and effect relationship, we firstly measure the degrees of employee satisfaction organized by 11 factors through survey, and also measure employees' overall satisfaction, organizational commitment and productivity. Secondly, we define service value as the employee's objective measure index and collect it with the data related to customer satisfaction. Based on the collected data, thirdly we define how the relationship among the employee satisfaction, the productivity, the service value and the customer satisfaction are affected by the employees' work abilities and overall satisfaction with SEM(Structural Equation Model). And finally, we classify employees according to their abilities and the degrees of satisfaction respectively and suggest important strategies to manage them effectively.

• KIEAE Journal
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• 제9권3호
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• pp.29-36
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• 2009

Interior material covering as the final process of house-building, critically influences not only aesthetic character but also air quality of indoor space. Wall covering today, however, caused a serious social problem because of chemicals contained in the industrial wallpaper and artificial glue. In this context, Korean traditional wall covering of Han-ji can be an alternative model due to it's ecological character. Recently 'Hanok' attracts public attention, since society and people become to appreciate the unique beauty and value of our traditional culture. The values include natural beauty, emotional character, and environment-friendliness. Recognizing this, this paper intended to scrutinize the operating process of Han-ji as an interior finish material. Historical research method was employed, tracing the related articles in old literature and interviewing with the witness of the experienced expert. Thereby, healthier and unique aesthetic indoor environment can be expected to be sustainable along with the rich cultural life of ancestors.

• 대한산업공학회지
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• 제24권3호
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• pp.359-365
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• 1998

An economic process monitoring procedure is presented when the major quality characteristic of the item is dichotomous. Every item is inspected and decided whether it is conforming or not. If an item is found to be nonconforming, the previous number of the successive conforming items is compared with a predetermined number r to check the process for existence of any assignable cause of variation. A cost model is constructed on the basis of costs of inspection, illegal signal, undetected out-of-control state and corrective action. By minimizing the expected total cost per unit time, the optimal value of r is obtained. The effects of cost coefficients are studied numerically.

• 한국식품저장유통학회지
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• 제10권3호
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• pp.314-319
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• 2003

가지의 수출 경쟁력 향상을 위한 한 방안으로 수출용 가지품종인 축양품종을 염가공품으로 개발하기 위하여 염절임 공정을 최적화하였다. 염절임 시간, 절임온도, 염농도를 독립변수로 하고 절임 후 수분함량, 염도, 표면과 내부의 색도 등을 종속변수로 하여, 중심합성계획법으로 실험을 설계하여 최적조건을 얻고자 하였다. 수립된 이차회귀모형으로 예측식을 수립할 수 있었으며 특히 수분함량이나 염도, 표면과 내부의 L과 b 값에 대하여 높은 적합도를 보여 최적조건을 수립하기 위한 제한 변수로 선정하였다. 염농도를 중심점(30%)에서 고정시켜서 얻은 절임시간과 온도는 각각 5.5-6.5일과 13-17$^{\circ}C$였으며, 이때의 종속변수의 제한 요건으로는 수분함량 84%이하, 염도 14%이하 표면 L 값 10-20, b값 0 이하, 내부 L 값은 70-75, b 값이 16-18이었다.