• 산업경영시스템학회지
• /
• 제17권30호
• /
• pp.51-57
• /
• 1994

This paper considers the problem of equipment replacement A equipment replacement problem is treated in a thchnological development environment. Our model assumes that the costs associated with the presently available thchnology and future technology is known, but the appearance times of future technology is uncertain. A cost model is presented, and method is suggested for finding the optimal operating time for replacement A numerical example is shown.

• 대한전기학회논문지
• /
• 제31권7호
• /
• pp.1-10
• /
• 1982

This paper derives the algorithm to estimate the operating cost, its marginal cost, and the reliability indices for the long term planning of power system. Treating the load duration curve and the system in the stochastic sense takes the place of the inverted load duration curve, effective load duration curve, and the numerical integration in the conventional methods. The time and accuracy of computation are substantially improved due to the fact that all expressions are represented by simple analytic form instead of the existing recursive form.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
• /
• pp.107-114
• /
• 2000

As one of the strategies to sustain the maximum output with the total minimum cost, huge plants worldwide, such as steel mills, refineries, petrochemical plants, and etc., may and will plan and implement the minimization of operating and maintenance costs for their own. This paper is to review the foreign cases of energy savings through lubrication improvements as one of the actions for that purpose and summarize their directions, and also to look at one such local test case.

• International Journal of Railway
• /
• 제2권4호
• /
• pp.139-146
• /
• 2009

Vehicle braking in non-electrified rail systems wastes energy. Advanced flywheel technology presents a way to capture and reuse this braking energy to improve vehicle efficiency and so reduce the operating costs and environmental impact of diesel trains. This paper highlights the suitability of flywheels for rail vehicle applications, and proposes a novel mechanical transmission system to apply regenerative braking using a flywheel energy storage device. A computational model is used to illustrate the operation and potential benefits of the energy storage system.

• 전기전자학회논문지
• /
• 제23권1호
• /
• pp.310-313
• /
• 2019

This paper used the majority function to digitally filter back-electromotive force as an explanation of the Brushless DC MOTOR control algorithm. The cause and improvement of motor noise, which are operating in close proximity to high frequency sources, did not use conventional low pass filter and comparator elements. Also, they repeatedly output a noise-free BEMF signal for the input value of the majority detection filtering. These filtering steps can help reduce costs and minimize the area of a PCB by requiring relatively little hardware.

• IEIE Transactions on Smart Processing and Computing
• /
• 제6권3호
• /
• pp.158-167
• /
• 2017

Internet-based social and interactive video applications have become major constituents of the envisaged applications for next-generation multimedia networks. However, inherently dynamic network conditions, together with varying user expectations, pose many challenges for resource allocation mechanisms for such applications. Yet, in addition to addressing these challenges, service providers must also consider how to mitigate their operational costs (e.g., energy costs, equipment costs) while satisfying the end-user quality of service (QoS) expectations. This paper proposes a heuristic solution to the problem, where the energy incurred by the applications, and the monetary costs associated with the service infrastructure, are minimized while simultaneously maximizing the average end-user QoS. We evaluate the performance of the proposed solution in terms of serving probability, i.e., the likelihood of being able to allocate resources to groups of users, the computation time of the resource allocation process, and the adaptability and sensitivity to dynamic network conditions. The proposed method demonstrates improvements in serving probability of up to 27%, in comparison with greedy resource allocation schemes, and a several-orders-of-magnitude reduction in computation time, compared to the linear programming approach, which significantly reduces the service-interrupted user percentage when operating under variable network conditions.

• 자원ㆍ환경경제연구
• /
• 제23권3호
• /
• pp.497-513
• /
• 2014

비용을 보상하는 원가규제 방식으로 알려진 투자보수율 규제 또는 총괄원가주의 규제의 경우 피규제자는 비용을 부풀리려는 유인을 갖게 마련이다. 그런데 생산공장별 원가를 규제자가 파악하고 이들 간의 경쟁을 유도하는 경우에는 단기적으로 '수인의 딜레마' 상황이 나타나 원가 과대보고와는 방향이 다른 원가 과소보고 방향으로의 비용왜곡 요인이 발생할 수 있다. 변동비 반영 전력시장의 경우 발전기의 운전시간이 늘어날수록 실제변동비와 등록변동비 간의 차이는 점점 커지게 되지만 복합화력 발전사들은 가동률과 발전량을 높게 유지하기 위해 등록변동비를 유지시키려는 전략적 선택을 할 수 있다. 그 결과 궁극적으로 수익성이 악화되고 신규설비에 대한 투자를 유도하지 못하며 설비예비율은 적정 이하로 떨어지는 '수인의 딜레마' 상황이 나타날 수 있다. 이에 따라 발전사들의 자기변동비가 실제 효율과 유사하도록 관련 규정을 개정할 필요가 있다.

• 가정간호학회지
• /
• 제10권1호
• /
• pp.52-57
• /
• 2003

The purpose of this study was to evaluate appropriateness of home health care travel cost. For the evaluation, investigated the operating costs of vehicles used by home care nurses and then were components of home care nurses's annual salaries. Travel costs were then calculated based on actual travel expenses of home health care service. Actual data of 23 hospital-based home care agencies between July, 2002 to December, 2002 were collected for the analysis of the travel costs. The results of this study are : 1) For home visit, 65% of home care agencies turned out to be using only hospital owned cars, and 17.1% be depending purely on home care nurses' cars. On average, 1.9 cars used for home visit. 2) Out of 89 agencies, 23 agencies responded to the travel cost survey. Total maintenance cost of a car per month was 381,457 won. 3) Average per visit personal expenses of home care nurses during travel time turned out to be 7,124won assuming 8 working hours per day, 4 visits per day, and 30 minuets of travel time for each visit. 4) Total home health care travel cost per visit was 12,069 won, which was the sum of actually paid travel cost of 4,945 won and personal expenses during travel time of 7,124. In conclusion. we reckon that current compensation price of home care nurses' travel is inappropriate because total home health care travel costs of 12,069 won per visit turned out to be 2.1 times of currently prevailing standard compensation price of 5,830 per visit.

• 한국건축시공학회지
• /
• 제16권2호
• /
• pp.141-149
• /
• 2016

기존의 대기전력차단시스템의 단점을 극복하고자 최근 지능형 대기전력 제어시스템이 개발되기에 이르렀다. 하지만 기존의 시스템 보다 투자금액이 높은 문제로 도입에 대한 타당성 검토가 필요하다. 이에 본 연구에서는 LCCA 및 LCA를 이용하여 경제적 측면 및 환경적 측면을 종합적으로 분석하여 도입의 타당성을 검토하였다. 또한 결과의 신뢰성을 확보하기 위하여 민감도 분석을 실시하였다.

• 방송공학회논문지
• /
• 제25권6호
• /
• pp.922-934
• /
• 2020

재능거래 플랫폼은 프로그램 코딩이나 미디어 콘텐츠 제작(동영상, 음악, 발표자료 등), 디자인, 학습, 수리 등의 거래를 중개하는 플랫폼이다. 기존 재능거래 플랫폼은 서버-클라이언트 모델 기반의 서비스를 제공하여, 서버를 운영하는 비용과 거래에 대한 중재 인건비가 발생하여 이용자들이 높은 서비스 수수료를 부담하는 단점이 있다. 본 논문은 이더리움 플랫폼 기반 분산앱(dApp)으로 시스템을 통해 거래 정보를 블록에 올려 서버 및 데이터베이스 운영 비용을 절감하는 방법을 제안한다. 아울러 스마트콘트랙트를 통해 거래 중재자 인건비를 절감하여 거래수수료를 낮추는 방법을 제안한다. 블록체인 기반 재능거래 플랫폼과 기존 재능거래 플랫폼의 비용 처리 절차 및 거래수수료의 크기를 비교 분석한다.