• 한국환경과학회지
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• 제25권3호
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• pp.439-446
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• 2016

Domestic sewerage treatment plant is operated by activated sludge method and its modified method by using microorganism. In most cases, a method of using microorganism is directly controlled by the operator based on individual judgment through factors of DO, pH and ORP. In addition, under aerobic condition in bioreactor, energy consumption including excessive air injection is learned to be somewhat plenty. In order to solve this problem, in most of the process, improvement of internal recycling and activated environmental factor of microorganism were researched extensively. However, as factors are changed depending on various conditions, it is not sufficient as an indicator of judgment. As such, a research on operation of bioreactor that measures metabolic change in short time by directly measuring activated condition of microorganism using NADH fluorometer is required in reality.It is considered that the method like this could supplement problem of energy consumption being occurred in the existing treatment method and operational optimization of bioreactor would be enabled by controlling optimal air volume. Therefore, in this study, in order to obtain optimal operational indicator of bioreactor, proper air volume control test was performed and through batch test and site evaluation, possibility of NADH sensor being utilized as operational control indicator of bioreactor is intended to be analyzed. In order to compare with measured value, DO, ORP that are operational control indicator of existing bioreactor were used. As MLSS concentration was increased through batch test, NADH value was increased and site evaluation also showed similar tendency to batch test. Resultantly, it could be confirmed that changing level of NADH fluorometer was a sensor that could measure bioreactor condition effectively and optimized scale of bioreactor is considered to be utilized.

• 한국항해항만학회지
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• 제44권3호
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• pp.181-186
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• 2020

지금까지 컨테이너 자동화 터미널의 설계 및 운영 모델 개발은 주로 수출입 화물의 양적·하 기능에 특화된 서구 항만을 대상으로 수행되었기 때문에, 부산항처럼 다양한 On-Dock 서비스가 요구되는 컨테이너 항만에서는 자동화 터미널의 도입과 운영에 많은 제약이 따른다. 이에 본 연구의 목적은 부산항을 사례로 현재 컨테이너 물동량 구조와 터미널 내부 운영 특성을 진단하고, 기존 자동화 터미널 운영 모델의 부분적인 변경을 통해 효과적인 공컨테이너 관리와 함께 터미널 운영비용을 절감하는 방안을 제시하는 것이다. 기존 수직 배열 자동화 컨테이너 터미널에 '인터체인지 이송 모델'을 적용하여 시뮬레이션 한 결과, 수정된 운영 모델은 구내 이송장비를 추가로 투입해야 하는 불리함에도 불구하고 기존 운영 모델 대비 최대 22%의 TAT 단축과 함께 연간 터미널 매출의 9.4%에 달하는 운영비용 절감이 가능한 것으로 나타났다.

• 대기
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• 제31권5호
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• pp.563-576
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• 2021

The performance of East Asian summer monsoon is assessed for GC2 and GC3.1, which are climate change models of the current and next climate prediction system in the Korea Meteorological Administration (KMA), GloSea5 and GloSea6. The most pronounced characteristics of GC models are strong monsoon trough and the weakening of the Western North Pacific Subtropical High (WNPSH). These are related to the weakening of the southwesterly wind and resulting weak monsoon band toward the Korean Peninsula. The GC3.1 is known to have improved the model configuration version compared to GC2, such as cloud physics and ocean parameters. We can confirm that the overall improvements of GC3.1 against GC2, especially in pressure, 850 hPa wind fields, and vertical wind shear. Also, the precipitation band stagnant in the south of 30°N in late spring is improved, therefore the biases of rainy onset and withdrawal on the Korean Peninsula are reduced by 2~4 pentad. We also investigate the impact of initialization in comparison with GloSea5 hindcast. Compared with GCs, hindcast results show better simulation within 1 month lead time, especially in pressure and 850 hPa wind fields, which can be expected to the improvement of WNPSH. Therefore, it is expected that the simulation performance of WNPSH will be improved in the result of applying the initialization of GloSea6.

• 품질경영학회지
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• 제47권1호
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• pp.139-150
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• 2019

Purpose: LST-II is a special naval ship to carry out landing operations by transporting tanks, armored vehicles and military vehicles. Bad weather, maximum wave height of 4-5 m, caused damage to the LCM cradles while the LST-II No.O ship was moving to Thailand for training in February 2016. Methods: Based on the results of the field check, DTaQ conducted a study on the causes analysis and improvement measures. Results: The improvement plan that was derived was verified through a structural analysis and the improvement plan was applied to the follow-up ships. Conclusion: The improvement of LCM cradle has increased the safety of the crew and landing forces, and improved the operational efficiency.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.63-72
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• 2017

본 논문에서는 공정분석, 작업분석 및 동작분석을 핵심으로 하는 고전적 IE기법들을 응용하여 자동차 부품 제조현장의 운영효율성 향상을 추구하는 절차를 제안하고 구체적 적용 사례를 보인다. 제안한 운영효율성 향상 절차는 사례기업인 L사의 차량전장부품 제조 사업부에서 공정개선팀을 구성하여 개발한 고유의 절차이며, 운영효율성의 척도로는 라인밸런스효율(Balance Efficiency)과 생산능력(Production Capacity)을 사용하였다. 개발한 절차는 제조 현장의 현상을 분석하고, 문제점을 해결하는 개선안을 도출하며, 도출된 각 대안을 평가하고 최종안을 선정하여 현장에 구현함으로써 생산성 향상을 달성하는 일반적 절차를 따르고 있다. 각 단계에 사용한 방법 중 낭비요소를 찾아내는 단계에 사용되는 기능분석과 대안 평가에 적용되는 R&R(Risk & Return)평가 기법은 사례기업인 L사에서 개발한 고유의 방법인데, 특히 R&R평가 기법은 응용성과 확장가능성이 큰 기법이므로 상세히 기술한다. 개발한 절차는 여러 공정에 적용하여 개선효과를 보았는데, 본 논문에서는 구체적 사례로서 개발한 절차를 전자식 조향시스템(EPS)의 핵심 부품인 EPS모터 제조 공정에 적용한 과정과 결과를 보인다. 개선절차를 적용하여 EPS모터 제조 공정을 개선한 결과 라인밸런스효율을 7.06% 높이고 생산능력을 15.5% 증대시킴으로써 운영효율성 향상을 달성하였다.

• Journal of Biosystems Engineering
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• 제12권2호
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• pp.28-37
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• 1987

Operation of rice whiteners has been depending on operator's experience only and very limitted data are available for operational criteria of rice whiteners in Korea. With developments of new rice varieties and with a tendency of automation of machine operations for precision control, operational criteria depending on physical characteristics of rice grains arc required for an improvement of milled rice recovery and the performance of rice whitening systems. An experimental study was conducted to identify operational criteria of a rice whitening system consisted with an abrasive-aerated whitener developed newly and a frictional-aerated whitener being used commercially. Further, comparisons were made between the performance of the rice whitening system adopted for this study and a commercial system used in small scale milling plants. Results of this study are summarized as follows: 1. Total number of passes necessary for the final white rice in the combined whitening system depended exclusively on the counter pressure level of the frictional whitener successive to the abrasive whitener. 2. The counter pressure required for whitening Japonica type rice variety (Akibare) was higher by about 1.6 times than that for Japonica type (Pung-san), when other conditions were kept at the same. 3. Radial pressure in the whitening chamber of the frictional whitener should be maintained between 1.5 to $2.1kg/cm^2$ for the completion of whitening within 5 to 3 passes regardless of rice varieties. Hence, it was found that the radial pressure in the whitening chamber could be used as an operational criteria to control the counter pressure level. 4. The following regression equation was found between radial pressure($R_p$) in whitening chamber and electric power consumption of the whitening system: $$EPC=-0.545\;R^2_p+1.277\;R_p+0.874[KWH/100kg]$$ 5. The following multiple regression equation was found among radial pressure ($R_p$), counter pressure ($C_p$), and bioyield point ($B_i$), length (L) and width (W) of brown rice. $$R_p/(B_i/W^2)=0.547\{C_p/(B_i/W^2)\}^{0.365}(L/W)^{0.120}(R^2=0.9897)$$ 6. The milled rice recovery and machine efficiency (kg/KWH) from the combined whitening system were higher by about 2.0% point and by 15 to 27% point than those from the conventional system, respectively.

• 항공우주시스템공학회지
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• 제1권3호
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• pp.13-20
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• 2007

The objective of this study is to investigate endurance test of localization part for T-50 aircraft engine. Major localization parts of the engine (F404-STW-102) was performed using Accelerated Simulated Mission Engine Test. The purpose of this test is to evaluate of quality demonstration capability, to verify design of engine localization parts, and to improvement safety and operation rate of T-50 advanced trainer by finding out operational problems in production phase and fixing it.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2016년도 춘계학술대회
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• pp.95-98
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• 2016

It is true that Aircraft accident investigation organization of Republic of Korea does not have independent role structurally and administratively. Also, in the event of an aviation accident it does not take the appropriate response and post-institutional measures for victims and their families support. With aware of this fact and to improvement this research paper present approach direction and suggestion of issues and implications for those by researching the operational practices of the United State's Victim Family support.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.36-41
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• 1988

Analog and Digital Speed Control Systems have mutually complementary properties. Analog System has good dynamic characteristics and moderate steady-state accuracy and can be implemented economically with operational a ampliers. Digital System, on the contray, has good static accuracy, but relatively poor dynamic property. So, a hybrid system which uses both digital and analog control can have good static and dynamic characteristics. In this paper, it is shown that a simple digital controller can improve steady-state accuracy of existing analog control system satisfactorily, and some design criteria are presented also.

• 경영과학
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• 제8권1호
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• pp.27-39
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• 1991

This paper describes the instructional flexible manufacturing system(FMS) laboratory facility at Virginia Polytechnic Institute(VPI) which is directed at problems and issues in the design, implementation and control of computer integrated manufacturing systems. It begins with a configuration and an operational description of FMS laboratory facilities. Next, relevant curricula in manufacturing systems design and control, which can use the FMS laboratory for instructional purpose, are introduced, A computer simulation can be used as an excellent tool for analysis prior to implementation of FMS as well as an on-going improvement tool. A brief survey of simulation languages is lastly included.