• 전기학회논문지
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• 제58권6호
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• pp.1057-1064
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• 2009

This paper introduces a new approach based on a quantum-inspired evolutionary algorithm (QEA) to solve unit commitment (UC) problems. The UC problem is a complicated nonlinear and mixed-integer combinatorial optimization problem with heavy constraints. This paper proposes a bounded quantum evolutionary algorithm (BQEA) to effectively solve the UC problems. The proposed BQEA adopts both the bounded rotation gate, which is simplified and improved to prevent premature convergence and increase the global search ability, and the increasing rotation angle approach to improve the search performance of the conventional QEA. Furthermore, it includes heuristic-based constraint treatment techniques to deal with the minimum up/down time and spinning reserve constraints in the UC problems. Since the excessive spinning reserve can incur high operation costs, the unit de-commitment strategy is also introduced to improve the solution quality. To demonstrate the performance of the proposed BQEA, it is applied to the large-scale power systems of up to 100-unit with 24-hour demand.

• 한국태양에너지학회 논문집
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• 제39권1호
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• pp.67-76
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• 2019

A ground source heat pump (GSHP) system can stable system operation by using underground heat source and has high reliability for energy production. However, wide-spread of the GSHP system is delayed to high initial investment costs. In previous studies, horizontal and unit-type ground heat exchanger (GHX) have developed to overcome disadvantages such as high initial cost. However, these performances of GHXs are greatly influenced by climate and weather conditions. It is necessary to analyze the performance of GHX according to the ground temperature change in the installation site. In this study, the ground temperature of each installation site confirmed and performance of unit-type GHX quantitatively analyzed by numerical analysis. As the result, the performance of the unit type GHX was 33.9 W/m in Seoul, 34.2 W/m in Daejeon, and 37.2 W/m in Busan.The result showed the difference performance of GHX according to local climate was maximum of 9.7%.

• Journal of Hospice and Palliative Care
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• 제10권1호
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• pp.29-34
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• 2007

목적: 본 연구는 위암과 폐암 말기로 진단받고 동일 병원에 입원하여 호스피스 대상자와 비대상자로 치료를 받다가 사망한 환자 114명을 대상으로 사망시점부터 14일 전까지의 진료비를 분석하여 양 대상을 비교하는데 있다. 방법: 진료비 분석에 대한 후향적 조사연구 설계로서 진료비 분석에 대한 도구는 C 대학 K 병원의 진료비 계산서 영수증을 기초로 하여 작성된 11개 항목에 대한 각각의 진료비 및 총액이었다. 결과: 호스피스 대상자의 진료비가 비 호스피스 대상자에 비해 낮았는데 특히 고단위 영양제, 마약성 진통제, 간호처치료, 방사선 검사, 혈액검사항목에서 통계적으로 유의하게 낮았다. 또한 호스피스 대상자 중에서는 호스피스 전담의의 유무에 따라 진료비의 총액에는 차이가 없었으나 기타 진통제 항목에서 전담의가 있었던 시기가 전담의가 없었던 시기에 비해 진료비용이 유의하게 높았다. 결론: 본 연구결과 동일기간 내 호스피스 대상자의 진료비용이 비 대상자에 비해 약 53%에 지나지 않음을 알 수 있어 범국가적인 차원의 호스피스 제도화 도입이 시급하다고 본다.

• 농업과학연구
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• 제43권4호
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• pp.603-611
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• 2016

The aim of this study was to analyze the contribution factors (backfat thickness, eye muscle area, carcass weight, marbling score, and feeding period) affecting meat unit price (South-Korean Won / Kg of meat). The best slaughtering age to maximize unit price was also assumed. All data used in this study were acquired from the Korea Institute for Animal Products Quality Evaluation from 2010 to 2014. Contributions to the estimated unit price of cows by the following factors, backfat thickness, eye muscle area, carcass weights, feeding period, and marbling score were 2.65%, 0.04%, 1.58%, 1.58%, and 95.72%, respectively. Contribution to estimated unit price of steers by the same factors (backfat thickness, eye muscle area, carcass weights, feeding period, and marbling score) were 7.88%, 1.24%, 0.07%, 90.81%, and 95.72%, respectively. Slaughtering ages ranged from 26 to 36 months and the data were separated into each month for an 11 month period. The unit price of meat from Hanwoo slaughtered at 30 months was highest among groups. The lowest unit price was observed in the group belonging to the Hanwoo slaughtered at 36 months. In conclusion, of all contributing factors, marbling score affected unit price the most. Based on our results, it is recommended that the optimal slaughtering age be set at 30 months to maximize unit price. Moreover, the feeding of beef cattle past 30 months of age is not recommended because of the increase in feeding costs.

• 제어로봇시스템학회논문지
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• 제9권5호
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• pp.407-412
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• 2003

An effective methodology is .reported for determining the optimal capacity (lot-size) of batch processing and storage networks which include material recycle or reprocessing streams. We assume that any given storage unit can store one material type which can be purchased from suppliers, be internally produced, internally consumed and/or sold to customers. We further assume that a storage unit is connected to all processing stages that use or produce the material to which that storage unit is dedicated. Each processing stage transforms a set of feedstock materials or intermediates into a set of products with constant conversion factors. The objective for optimization is to minimize the total cost composed of raw material procurement, setup and inventory holding costs as well as the capital costs of processing stages and storage units. A novel production and inventory analysis formulation, the PSW(Periodic Square Wave) model, provides useful expressions for the upper/lower bounds and average level of the storage inventory hold-up. The expressions for the Kuhn-Tucker conditions of the optimization problem can be reduced to two subproblems. The first yields analytical solutions for determining batch sizes while the second is a separable concave minimization network flow subproblem whose solution yields the average material flow rates through the networks. For the special case in which the number of storage is equal to the number of process stages and raw materials storage units, a complete analytical solution for average flow rates can be derived. The analytical solution for the multistage, strictly sequential batch-storage network case can also be obtained via this approach. The principal contribution of this study is thus the generalization and the extension to non-sequential networks with recycle streams. An illustrative example is presented to demonstrate the results obtainable using this approach.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1859-1864
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• 2004

An effective methodology is reported for the optimal design of multisite batch production/transportation and storage networks under uncertain demand forecasting. We assume that any given storage unit can store one material type which can be purchased from suppliers, internally produced, internally consumed, transported to or from other plant sites and/or sold to customers. We further assume that a storage unit is connected to all processing and transportation stages that consume/produce or move the material to which that storage unit is dedicated. Each processing stage transforms a set of feedstock materials or intermediates into a set of products with constant conversion factors. A batch transportation process can transfer one material or multiple materials at once between plant sites. The objective for optimization is to minimize the probability averaged total cost composed of raw material procurement, processing setup, transportation setup and inventory holding costs as well as the capital costs of processing stages and storage units. A novel production and inventory analysis formulation, the PSW(Periodic Square Wave) model, provides useful expressions for the upper/lower bounds and average level of the storage inventory. The expressions for the Kuhn-Tucker conditions of the optimization problem can be reduced to two sub-problems. The first yields analytical solutions for determining lot sizes while the second is a separable concave minimization network flow subproblem whose solution yields the average material flow rates through the networks for the given demand forecast scenario. The result of this study will contribute to the optimal design and operation of large-scale supply chain system.

• 한국주거학회논문집
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• 제25권1호
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• pp.51-61
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• 2014

The purpose of this study was to explore housing characteristics of young single- or two-person households in the U.S. metropolitan urban areas and determinants of their housing cost burden. Total 764 single-person households, 744 two-person households and 424 households with three or more persons were selected from the 2011 American Housing Survey public-use microdata for the study based on specific sampling criteria. The major findings are as follows: (1) In comparisons with larger households, single- or two-person households were characterized to be headed by younger householders, to have less income, and to have a greater proportion of households living in central cities of metropolitan areas, renting housing units, living in smaller size units or multifamily structures; (3) housing cost of single- or two-person households were significantly less than a larger households while housing costs per unit square footage (SQFT) of single- or two-person households was significantly greater; (4) regardless of the household size, there are many household headed by young college graduates paying too much of their income for housing, and single-person households were found to have the greatest housing cost burden; and (5) a linear combination of low-income status, monthly housing costs per unit SQFT, annual household income, and unit SQFT per person was found to be most efficient to predict single- or two-person households with housing cost burden.

• 제어로봇시스템학회논문지
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• 제10권6호
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• pp.537-544
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• 2004

An effective methodology is reported for determining the optimal lot size of batch processing and storage networks which include uncertain demand forecasting. We assume that any given storage unit can store one material type which can be purchased from suppliers, internally produced, infernally consumed, transported to or from other sites and/or sold to customers. We further assume that a storage unit is connected to all processing and transportation stages that consume/produce or move the material to which that storage unit is dedicated. Each processing stage transforms a set of feedstock materials or intermediates into a set of products with constant conversion factors. A batch transportation process can transfer one material or multiple materials at once between sites. The objective for optimization is to minimize the probability averaged total cost composed of raw material procurement, processing setup, transportation setup and inventory holding costs as well as the capital costs of processing stages and storage units. A novel production and inventory analysis formulation, the PSW(Periodic Square Wave) model, provides useful expressions for the upper/lower bounds and average level of the storage inventory. The expressions for the Kuhn-Tucker conditions of the optimization problem can be reduced to two sub-problems. The first yields analytical solutions for determining lot sires while the second is a separable concave minimization network flow subproblem whose solution yields the average material flow rates through the networks for the given demand forecast scenario. The result of this study will contribute to the optimal design and operation of the global supply chain.

• 대한교통학회지
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• 제35권4호
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• pp.292-306
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• 2017

교통 소음비용은 피해비용 접근법 또는 회피비용 접근법으로 평가할 수 있다. 본 연구는 피해비용 접근법을 바탕으로 소음의 외부비용을 산정하는 방안을 제시하였다. 이를 위하여 네 가지를 검토하였다. 첫째, 한국의 실정에 맞는 소음피해 비용 원단위 41,737-601,910 원/(인 년)를 도출하였다. 둘째, 소음도 예측식을 이용하여 소음 영향권을 설정하였다. 셋째, 소음 영향권 내에서 소음에 노출된 인구와 실제 피해인구 비율의 곱으로 소음피해 인구를 추산하였다. 마지막으로 소음의 피해비용을 산출하는 과정을 간소하게 하는 소음 피해비용과 소음도간 관계식을 제시하였다. 이를 바탕으로 피해비용 접근법과 회피비용 접근법으로 소음저감 편익을 산출하고 비교함으로써 피해비용 접근법이 회피비용 접근법보다 이론적 정합성과 정책적 신뢰성이 높은 방법론임을 확인하였다.

• 대한교통학회지
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• 제28권5호
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• pp.43-54
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• 2010

본 연구에서는 현행 버스 서비스 평가체계를 보완하고 선행연구에 비해 합리적인 분석결과를 도출하기 위해 유익 유해산출물을 모두 반영한 수정 BCC 모형을 이용하여 2009년 서울시 113개 간선버스노선의 효율성을 추정하였다. 분석대상은 총 보유비와 총 가동비, 중앙차로 정류장수 비율과 타노선과의 중복길이를 사용하여 유익산출물인 총 승객수와 서비스 만족도 점수, 그리고 유해산출물인 CO2 배출량을 산출하는 형태로 상정하였다. 분석결과 유해산출물을 함께 반영한 모형이 유익산출물만을 반영한 모형에 비해 합리적인 결과를 도출하는 것으로 나타났다. 서울시 간선버스노선은 총 보유비와 총 가동비, 그리고 타노선과의 중복길이를 평균적으로 약 10% 감소할 수 있으며, 중앙차로 정류장수 비율은 약 160% 증가시킬 수 있는 것으로 분석되었다. 한편 효율성에 영향을 미치는 결정요인을 분석하기 위한 토빗회귀분석을 수행한 결과 총 보유비와 중앙차로 정류장수 비율이 통계적으로 유의미성을 확보하였다.