• 대한기계학회논문집
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• 제16권2호
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• pp.236-247
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• 1992

Optimization has been developed to minimize the cost function while satisfying constraints. Nonlinear Programming method is used as a tool for the optimization. Usually, cost and constraint function calculations are required in the engineering applications, but those calculations are extremely expensive. Especially, the function and sensitivity analyses cause a bottleneck in structural optimization which utilizes the Finite Element Method. Also, when the functions are quite noisy, the informations do not carry out proper role in the optimization process. An algorithm called "Second-order Approximation Method" has been proposed to overcome the difficulties recently. The cost and constraint functions are approximated by the second-order Taylor series expansion on a nominal points in the algorithm. An optimal design problem is defined with the approximated functions and the approximated problem is solved by a nonlinear programming numerical algorithm. The solution is included in a candidate point set which is evaluated for a new nominal point. Since the functions are approximated only by the function values, sensitivity informations are not needed. One-dimensional line search is unnecessary due to the fact that the nonlinear algorithm handles the approximated functions. In this research, the method is analyzed and the performance is evaluated. Several mathematical problems are created and some standard engineering problems are selected for the evaluation. Through numerical results, applicabilities of the algorithm to large scale and complex problems are presented.presented.

• KIEE International Transactions on Power Engineering
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• 제5A권3호
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• pp.228-234
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• 2005

This paper presents the evaluation of reactive power pricing through the control of generator voltages under the assumption that the reactive power market has been transformed into the real power market. By applying the concept of economic dispatch, which minimizes the total cost of real power generation to reactive power generation, the algorithm for implementing reactive power pricing is proposed to determine the optimum voltage profiles of generators. It consists of reactive power voltage equation, the objective function that minimizes the total cost of reactive power generation, and linear analysis of inequality constraints in relation to the load voltages. From this algorithm, the total cost of the reactive power generation can be yielded to the minimum value within network constraints as the range of load voltages. This may provide the fair and reasonable price information for reactive power generation in the deregulated electricity market. The proposed algorithm has been tested on the IEEE 14-bus system using MATLAB.

• 패션비즈니스
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• 제26권1호
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• pp.53-67
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• 2022

The purpose of this study was to compare the appearance similarity between a 3D virtual wedding dress, and a model wearing real dress, and production efficiency, and the possibility of achieving similar results with 3D digital technology. Five wedding dresses for small weddings under the theme of 'Dream Series', were designed and produced in virtual and real dresses to quantitatively compare and analyze the appearance similarity and production efficiency. Experts compared the appearance similarity on the silhouettes, colors, materials, and details, and production efficiency was compared with time and cost. Based on our results, 3D virtual images of four out of the five dresses were similar to the real images. Our efficiency evaluation results showed that the manufacturing time was 45.4% shorter, and the manufacturing cost was 46.1% less than the existing method. This indicated that the wedding dress manufacturing process using 3D virtual software was time and cost saving competitive. Our results also confirmed that 3D virtual software technology has the potential to increase the efficiency of designing and production, and therefore an increase in competitiveness and sales of wedding dresses. Furthermore, 3D technology allows consumers to select and order wedding dresses online through 3D virtual software. This is a great advantage, and it highlights the significance of this research study.

• 한국건축시공학회지
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• 제13권6호
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• pp.585-593
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• 2013

본 연구에서는 건축물의 전생애주기 동안의 경제적 비용과 환경적 비용을 합리적이고 종합적으로 평가할 수 있는 효용성 높은 LCC-LCA 종합분석 모델을 제안하고, 이를 실제사례에 적용하고 기존의 분석방법들과 비교하여 에너지 절감측면이 부가된 본 모델의 유효성을 검증하고자 한다. 개선된 LCC 분석과 일반적인 LCC 분석을 실시하여, 각 대안의 연간 소요되는 누적비용을 산출한 결과 모두 동일하게 경과년수 20년을 기점으로 손익분기점이 발생하였다. LCC 분석의 모든 평가항목을 적용하지 않고 가중치 및 영향도가 높은 평가항목들을 선별하여 경제성 평가를 수행하는 것이 보다 효율적임을 알 수 있다. 개선된 LCC 분석을 통해 각 대안별 소요되는 누적비용을 산출한 결과 경과년수 20년을 기점으로 손익분기점이 발생하였으며, 개선된 LCC-LCA 종합분석을 적용한 경우 개선된 LCC 분석 결과에 비해 손익분기점이 10년이 단축되었다. 이는 비용적 측면과 환경적 측면을 모두 고려하는 것이 보다 객관적인 대안의 선택이 가능한 것으로 나타났다. 실제 건축물에 활용하기 위한 개선된 LCC-LCA 종합분석의 평가항목은 경제성 평가 시 영향도 및 가중치가 높은 평가항목의 선별을 통해 일반적인 LCC 분석의 모든 평가항목을 적용하지 않고 선별한 평가항목들을 비용 산출하여 경제성 평가를 실시하는 것이 합리적인 평가 방법으로 사료된다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.423-426
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• 2002

현재 우리나라에서는 건설공사비 산출방식을 실적공사비 적산제도로 전환하기 위한 기반을 마련 중에 있다. 실적공사비 적산제도가 원활하게 시행되기 위해서는 이에 필요한 각종 실적자료가 필요하다. 공사비 지수는 이러한 실적자료의 하나로서 외곽의 경우에는 정부 및 민간기관에서 공사비 지수를 제공해 주고 있지만, 국내의 경우는 도로공사를 제외하고는 건설공사에서 적용할 수 있는 공사비 지수가 공표되지 않고 있는 실정이다. 공사비 지수는 건설공사의 입찰가 분석, 단가 및 공사비 조정, 공사비 예측을 위해 사용하는 것으로, 본 연구에서는 단지조성공사 설계내역서 22개를 표본으로 하여 우리나라와 영국에서 사용되고 있는 공사비 지수 작성기준을 비교하여 국내의 공사비 지수 산출방식의 문제점을 분석하였으며, 그 개선방안과 함께 단지공사용 공사비 지수를 작성하여 제시하였다.

• 전기학회논문지
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• 제59권4호
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• pp.679-685
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• 2010

As the electrical power industry is restructured, the electrical power exchange is becoming extended. One of the key information used to determine how much power can be transferred through the network is known as available transfer capability (ATC). To calculate ATC, traditional deterministic approach is based on the severest case, but the approach has the complexity of procedure. Therefore, novel approach for ATC calculation is proposed using cost-optimization method, well-being method and risk-benefit method in this paper. This paper proposes the optimal transfer capability of HVDC system between mainland and a separated island in Korea through these three methods. These methods will consider production cost, wheeling charge through HVDC system and outage cost with one depth (N-1 contingency).

• 가정과삶의질연구
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• 제18권1호
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• pp.43-52
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• 2000

The purpose of this study was to investigate the levels of subjective cost-of-living and its determinants. 328 housewives who live in Seoul were selected as the sample of this study and surveyed by questionnaire method. Results showed that the mean value of subjective cost-of living was 1,280 thousand won for the poverty level of living 1,990 thousand won for the standard level of living and 3,020 thousand won for the sufficient level of living. The determinants of the level very with the level of the living however the actual level of consumption expenditures and the education level of respondents were positively related with all three levels of the subjective cost-of-living while the self evaluation for own life was negatively related with them.

• 한국건축시공학회지
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• 제1권1호
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• pp.135-142
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• 2001

This study is for the investigation of form using the aluminum-compound metal frame(Aluminum frame reinforced panel : AFR panel) which is improved in the capacity in the wall-concrete structure in steal of using the existing form which has problems such as, excessive exposure of cement, the loss of labor when it is constructed or disjointed, and it's economical efficiency compared with that of EURO Form. AFR panel passes the KS F 8006 test, and as a result of field test, it's displacement is satisfied with Specification. And using AFR panel is more economical than that of EURO Form because saving labor cost which plays a major part in cost saving in formwork is more effective in retrenching total cost than increment of material cost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.686-687
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• 2011

In this paper, the method on calculating benefits of combined heat and power is introduced for standard evaluation in electrical power system. This paper calculates benefits about new national viewpoint and viewpoint of independent power producers and assesses benefits of combined heat and power in Korea and In Seoul national capital area. Benefit costs are composed of avoid cost of centralized generation, line upgrading adjustment, loss adjustment and electrical power trade cost per year in earlier study, in addition trade cost of CO2, construction cost of combined heat and power for accurate calculation. Benefit of combined heat and power is calculated by simulation results of real electrical power system.

• 대한산업공학회지
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• 제27권3호
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• pp.297-304
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• 2001

Procurement decisions for inspection equipment are often made heavily based on the initial purchase price instead of the effects of inspection cost, equipment calibration and utilization over the lifetime. Cost of ownership(COO) models that take into account all of these cost factors together have been developed focusing on a single quality characteristic. In modern manufacturing environment, inspection equipment often can deal with more than one quality characteristic simultaneously. In this paper, we propose the revised COO model for the economic evaluation of the inspection equipment that can accommodate multiple quality characteristics. We also employ an engineering economy model to compare equipments with different life span. Software is developed for handy comparison of the COO of alternative equipments along with sensitivity analysis far the optimal procurement decision.