• 한국항해항만학회지
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• 제28권4호
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• pp.285-291
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• 2004

The productivity of container terminal is determined by its various operation methods. This paper aims at finding out the factors to enhance the productivity of container handling of quay crane, using simulation technique. Three levels of decision making in terminal operation, strategy, and tactics and operation are selected for defining parameters of simulation The result of the simulation and test shows that the significant factors to improve the productivity are the stack height of container, block dispersion and the distance in yard planning for shipment. Decision making in the operation level, however, is of significance in the mixed condition of strategic and tactical level. The result shows meaningful guidelines in decision making under strategic, tactical and operation level.

• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.363-370
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• 2003

This paper presents the analysis of the load transfer capacity and study of conductor size for variable contingencies in distribution systems. The operation capacity of feeders was changed to improve operation efficiency in KEPCO, considerations for contingencies are still based on the previous capacity. In order to cope with the changes such as operation capacity, it is necessary to study whether the present "contingency support criteria" is reasonable or not, also to confirm the whether the present criteria should be improved or not. We analyze the load transfer capacity and conductor size on a distribution system for contingency levels such as the substation-level, bank-level, feeder-level, and zone-level.one-level.

• 농업생명과학연구
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• 제53권1호
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• pp.117-126
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• 2019

본 연구는 수평 원통형 퇴비화 장치를 이용하여 퇴비를 생산할 때, 폐사축을 동시에 처리할 수 있는 가능성 여부를 판단하기 위하여 실험을 진행하였다. 그 결과 중금속의 경우, 아연의 함유량이 일반 운전의 일부 측정구와 폐사축 운전의 전체 측정구에서 허용함유량 보다 초과하는 것으로 나타났다. 특히 폐사축 운전의 경우, 구리 함량도 일반 운전에 비해 높게 나타났다. 우드칩 운전의 경우, 모든 중금속이 허용치보다 낮게 나타났으며, 구리, 카드뮴 및 비소의 경우는 폐사축 운전과 유사하거나 동일 수준으로 나타났다. 단지 니켈의 함유량이 29.5~63.8% 정도로써 일반 및 폐사축 운전에서 각각 9.3~18.0% 및 15.8~18.0% 정도 함유한 것에 비해 상대적으로 높게 나타났다. 그리고 크롬의 경우도 14.2~31.9% 정도로서 일반 및 폐사축 운전에 비해 상대적으로 높게 나타났다. 통합 운전의 경우도 모든 중금속이 허용치보다 낮게 나타났으며, 구리와 아연의 함유량은 각각 34.9~54.5% 및 53.1~75.9% 정도로서 우드침 운전의 경우인 48.9~52.6% 및 64.6~85.9% 정도와 유사하였다. 그리고 우드칩 운전에서 다소 높게 나타났던 크롬과 니켈의 함량도 안정화 된 것으로 나타났다. 함수율은 폐사축 운전의 경우, 평균 및 최종치가 60.7% 및 49.6% 정도로서 평균치가 권장치인 55.0% 보다 다소 높게 나타났지만, 최종 함수율은 권장치인 55.0% 보다 낮게 나타났다. 통합 운전의 경우, 평균 및 최종 함수율이 각각 29.2% 및 18.6% 정도로서 4개의 운전 중에 상대적으로 가장 낮게 나타났다. 그리고 운전별로 다소차이는 있지만, 전체적으로 권장치인 55.0% 보다 낮게 나타났다. C/N비의 경우, 폐사축 운전에서 상대적으로 가장 낮게 나타났고, 일반 운전에서 가장 높게 나타났다. 운전별로 보면, C/N비의 평균치가 13.7~20.3 정도의 범위이고, 전체평균이 18.3 정도로서 전체적으로 적정치인 30.0 이하를 유지하였다.

• 한국농공학회논문집
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• 제64권4호
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• pp.11-20
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• 2022

Currently, the operation rule of agricultural reservoirs in case of drought events follows the drought forecast warning standard of agricultural water supply. However, it is difficult to preemptively manage drought in individual reservoirs because drought forecasting standards are set according to average reservoir storage ratio such as 70%, 60%, 50%, and 40%. The equal standards based on average water level across the country could not reflect the actual drought situation in the region. In this study, we proposed the improvement of drought operation rule for agricultural reservoirs based on the percentile approach using past water level of each reservoir. The percentile approach is applied to monitor drought conditions and determine drought criteria in the U.S. Drought Monitoring (USDM). We applied the drought operation rule to reservoir storage rate in extreme 2017 spring drought year, the one of the most climatologically driest spring seasons over the 1961-2021 period of record. We counted frequency of each drought criteria which are existing and developed operation rules to compare drought operation rule determining the actual drought conditions during 2016-2017. As a result of comparing the current standard and the percentile standard with SPI6, the percentile standard showed severe-level when SPI6 showed severe drought condition, but the current standard fell short of the results. Results can be used to improve the drought operation criteria of drought events that better reflects the actual drought conditions in agricultural reservoirs.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.196-197
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• 2014

Low carbon construction is an important operation management goal such as cost, time, and quality in construction community. This paper introduces a system which measures the variability of carbon dioxide amounts. First, this system allows creating construction operation models of which the level of detail is breakdown into the work task level. Second, the system implements sensitivity analysis along with a ranges of resources that are allocated in an operation model. It facilitates to find the optimal resource combination using the operation performances such as the amount of emissions, operation completion time, and cost. Lastly, it identifies the best fit probability distribution functions of performance criteria given a certain resource combination. It allows project manager to query the percentages to complete the operation within a limitation specified by the system users.

• Journal of Community Nutrition
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• 제8권3호
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• pp.127-133
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• 2006

This study attempted to investigate and compare the level of needs and expected benefits of information technology(IT) applications in restaurant operation from managerial and employee levels. Self-competence levels, education and training needs, and the company IT application levels were evaluated. The respondents for the study were the staff of full-service, mid-scale restaurants owned by a firm. Among the respondents, 17.6% were in managerial level(managers) and 82.4% were in employee level(employees). The results of this study indicated that compared to employees, managers perceived more in-depth that IT is beneficial and is needed in restaurant operation. Both groups rated IT as very much needed and beneficial to restaurant operation. However, managers rated their own technological competence significantly higher than the employees did. Both groups expressed the desire for IT training and education although the managers' needs were stronger than the other group. The company's IT application level was assessed by the managers and employees at a slightly higher than average score on a 5-point scale, showing no difference between the groups. The study findings show that the respondents perceived the IT needs and benefits than the present IT application level of restaurants, which suggests more IT applications be adopted to the restaurant operations.

• 전력전자학회논문지
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• 제19권4호
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• pp.376-382
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• 2014

This paper proposes the pulse width modulation (PWM) control strategy for low-speed operation in the three-level neutral-point-clamped (NPC) inverters based on the bootstrap gate drive circuit. As a purpose of the cost reduction, several papers have paid attention to the bootstrap circuit applied to the three-level NPC inverter. However, the bootstrap gate driver IC cannot generate the gate signal to the IGBT for low-speed operation, because the bootstrap capacitor voltage decreases under the threshold level. For low-speed operation, the dipolar and partial-dipolar modulations can be the effective solution. However, these modulations have drawbacks in terms of the switching loss and THD. Therefore, this paper proposes the PWM control strategy to operate the inverter at low-speed and to minimize the switching loss and harmonics. The experimental results are presented to verify the validity on the proposed method.

• 융합경영연구
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• 제7권1호
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• pp.1-14
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• 2019

Purpose - Currently, the economic globalization has become a common channel for China's enterprise to perform the international economic activities. Due to this background, this paper tries to analyze the influence of internationalization level on operation performance of enterprises. Research design, data, and Methodology - This paper aims at 296 companies going listed in Shanghai Stock Exchange and Shenzhen Stock Exchange. The data about the listed companies during the 12 years from 2005 to 2016 have been collected. Relevant theories, including the theory of comparative advantage, monopolistic advantage and product life cycle in developed countries as well as the small scale technology and state on localized technological capacities in developing countries, have been summarized to provide theoretical basis for the influence of international operation on operation performance of the enterprises. Moreover, the current status of international operation of China's enterprises, including the dynamic cause of the internationalization of China's enterprises, its competitive advantage and disadvantage as well as the interest and potential risk of the internationalization, have been also analyzed. Results - Via adopting the panel data to conduct an empirical analysis, It can be found that the relationship between international operation level and operation performance of China's enterprises can be expressed as the S-curve of declining, rising and declining again. Conclusions - This paper has taken the lead in using Ohlson corporate value model to fill the gap in the relevant researches in China. It can also provide guidance for the international operation of China's enterprises. Meanwhile, the two systems for international operation and performance evaluation index have been put forward. The performance of international operation can be classified as financial performance or corporate value so that the operation effect of those China's enterprises going abroad can be better evaluated.

• 한국수자원학회논문집
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• 제45권9호
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• pp.959-968
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• 2012

주운수로 홍수기 수위 산정을 위하여 미 공병단에서 개발한 HEC-RAS 모형을 적용하였다. 아라뱃길은 다양한 수리구조물의 조작을 통하여 선박운항 및 홍수처리가 이루어지며 유입홍수, 한강수위, 그리고 서해조위 변동과 연계하여 귤현보, 서해배수문, 체절수문, 그리고 배수펌프장등의 대표적인 구조물 운영을 지원할 수 있는 홍수위 계산모형이 필요하다. 특히 서해배수문의 개도를 결정하기 위하여 외조위와 내수위 변동을 동시에 고려한 수문운영이 필요하여 HEC-RAS의 Rule-script 기능을 적용하여 이러한 특성을 반영하였다. 모형의 검보정을 위하여 2010년 9월 홍수사상을 적용하였으며 모형으로부터 계산된 수위값과 관측된 수위값이 서로 잘 일치함을 확인하였다. 본 연구에서 구축된 HEC-RAS모형은 홍수기 주운수로 운영에 기여할 것으로 판단된다.

• 한국경영과학회지
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• 제17권3호
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• pp.27-46
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• 1992

This paper considers an (r, Q) policy for operation of a multipurpose facility. It is assumed that whenever the inventory level falls below r, the model starts to produce the fixed amount of Q. The facility can be utilized for extra production during idle periods, that is, when the inventory level is still greater than r right after a main production operation is terminated or an extra production operation is finished. But, whenever the facility is in operation for an extra production, the operation can not be terminated for the main production even though the inventory level falls below r. In the model, the demand for the product is assumed to arrive according to a compound Poisson process and the processing time required to produce a product is assumed to follow an arbitary distribution. Similarly, the orders for the extra production is assumed to accur in a Poisson process are the extra production processing time is assumed to follow an arbitrary distribution. It is further assumed that unsatisfied demands are backordered and the expected comulative amount of demands is less than that of production during each production period. Under a cost structure which includes a setup/ production cost, a linear holding cost, a linear backorder cost, a linear extra production lost sale cost, and a linear extra production profit, an expression for the expected cost per unit time for a given (r, Q) policy is obtained, and using a convex property of the cost function, a procedure to find the optimal (r, Q) policy is presented.