• 대한설비공학회지:설비저널
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• 제19권2호
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• pp.67-81
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• 1990

The objective of this is to develop a practical software package to calculate annual energy consumption of HVAC (Heating Ventilating, and Air Conditioning) System in a building. It can quickly estimate loads and energy consumption, and have a function of economic analysis through the estimation of operating cost. Techniques of save energy consumption used in a building are necessary from the stage of design process to operation. The single most significant task is on HVAC Systems. Their installation costs, and related operating costs have enormous influence upon initial and maintenance costs. HVAC designers and engineers now have a wide variety of software choices available, but only a few of them have been developed in this country and no source program has been disclosed. Neither load culculation nor estimation of energy consumption is systematically made by the domestic HVAC design firms. Even though computer improved over the years with a trend of large scale load calculation and system selection through simulaion, the utilization of software nowadays does not make good progress due to lack of working environment. Therefore, it is necessary to develop a practical software package with which load calculation can be made with ease and kind manner. This study concerns the development of a software package which makes it possible to design HVAC system and save energy consumption in operation. The algorithm used in this program is a Modified Bin Method widely known as a simplified energy analysis means.

• 한국축산시설환경학회지
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• 제2권1호
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• pp.27-39
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• 1996

낙농 전업농의 최적 기계장치 모델을 설정하는데 필요한 자료를 수집하고자 경기도 낙농가 중 사육규모 별로 經産牛 30두 미만, 30~50두, 50두 이상 각 5농가씩 15농가를 현지 방문하였다. 작업공정별 작업방법, 노동투하시간, 작업 비용 분석자료를 조사, 분석하고 관련 자료들을 수집하여, 經産牛 30두 내외규모, 40두 내외규모, 50두 내외규모에서의 최소 작업비용 기계장치 사육체계를 설정하여 우리나라의 절반 이상 낙농가에서 이용하고 있는 繫留式 牛舍, 양동이식 착유기 중심의 관행 작업 체계와 비교 분석한 결과는 다음과 같다. 1. 관행작업체계에서는 가족 노동 1.5인 기준 년 2,700시간으로 經産牛 15두까지 사육 가능하며, 이 때 필요한 총작업비용은 734천원/년ㆍ두로 산출되었다. 2. 繫留式 牛舍에서 최소작업비용을 구한 결과 호퍼식 농후사료 급여, 워터컵 급수, 파이프 라인 착유, 반크리너 분뇨청소에서는 經産牛 28두까지 사육 가능한 것으로 나타났으며, 총작업 비용은 520천원/년ㆍ두로 산출되었다. 3. 放飼式 牛舍는 繫留式 牛舍 보다 30두 내외로 사육하는 경우에는 총작업 비용이 더 높았다. 放飼式 牛舍의 최소 작업비용체계는 1열$\times$5두식 헤링본 착유실 착유, 농후사료 자동급여, 무가온보온급수, 스키로더 분뇨청소의 체계로, 經産牛 30두까지 사육 가능한 것으로 나타났으며, 총 작업 비용은 582천원/년ㆍ두로 나타났다. 4. 放飼式 牛舍 40두 내외 규모에서의 최소 작업비용체계는 2열$\times$4두식 헤링본 착유실 착유, 농후사료자동급여, 무가온보온급수, 스크레퍼 분뇨청소 체계로, 經産牛 41두까지 사육 가능하고 작업 비용은 501천원/년ㆍ두로 나타났다. 5. 放飼式 牛舍 50두 내외 규모에서의 최소 작업비용체계는 2열$\times$3두식 탠덤 착유실, 농후사료 자동급여, 무가온 보온급수, 스크레퍼 분뇨청소체계로, 經産牛 52두까지 사육가능하고 작업 비용은 500천원/두로 나타났다.

• 전기학회논문지
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• 제59권5호
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• pp.871-881
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• 2010

In the uniform price electricity market or bilateral electricity market, the energy transactions in which the network is not considered and ISO's system operation costs which ISO try to minimize are settled separately. In this paper, transmission loss, one of the ISO's system operation costs, was dealt. The conventional marginal loss allocation method gives economic signals but three aspects have to be considered; excessiveness, arbitrariness and cross-subsidy. In this paper, marginal loss compensation efficiency method was suggested which consider those aspects of the conventional marginal loss allocation method. Also the characteristics of the marginal loss compensation efficiency were analyzed in the appendixes. And simple 2-bus system and IEEE 14 bus system were used to explain these characteristics.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1623-1629
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• 2010

The high speed rolling stock system considerably belongs to a special industry which requires large-scale investment cost but the recovery term is long. Therefore, to guarantee risk and possibility of technological success in initial investment, tools concerned with various expecting methods like life cycle costs analysis and credibility management are used. In view of this characteristics, the cases on cost structure for HSR RS previously invested should be studied and the method to appropriately allocate the life cycle of each sub-system like arrangement unit, electric device, braking device, door and car body should be realized. Moreover, the environmental aspects of main manufacturer and parts supplier can be checked. This study, through the case study for HSR cost structure in introduction and operational stage of KTX, aims to seek for the method to adapt to environmental changes like EU railway industry of which object is to acquire global market competitiveness by integrating manufacturing and operation of RS and the regulation and operation of IRIS which is performed in Europe.

• 산업경영시스템학회지
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• 제17권32호
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• pp.1-6
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• 1994

Many vehicle routing methods have been suggested, which minimize the routing distances of vehicles to reduce the total transportation cost. In describing a distribution network, we have stated that it is basically a system or a set of locations that, receive or store material plus the routes that connect these locations. Whether the network is spread over some geographic region or is whitin a single facility, the definition remains the same. Implicit in this definition, however, is that both the locations and the transportation between these locations must be considered in any decisions regarding the design of the operation of the overall network. The purpose of this paper is optimal layout using transportation quantity and distance in the total system operation. And we minimize the sum of load-carrier costs and spur costs in this flow network.

• 전기학회논문지
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• 제57권2호
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• pp.164-171
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• 2008

This paper proposes the planning method for placement of capacitors in a distribution system. The main objectives in the planning for capacitor allocation are the reduction of installation costs and electric power loss. In the proposed method, the life time of each device is considered in calculating installation costs, and the optimal operation status of devices is found by genetic algorithm. Then, the optimal numbers and locations are determined based on the optimal operation status. Simulation results in the 69-bus distribution system show that the proposed method performs better than conventional methods.

• 한국경영과학회지
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• 제25권2호
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• pp.1-10
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• 2000

With every passing month a number of new virtual enterprises emerge on the internet. Many companies have responded to the idea of distributed manufacturing in which the value adding activities comprising a finished product are dispersed geographically in a remote place. This study suggests an idea for selecting suppliers in a distributed manufacturing environment which enables machining companies to share their capacities. A mathematical model is constructed to show how to minimize the sum of the operation and transportation costs based on alternative process plans considering several kinds of operation characteristics in the real world. Four heuristic algorithms are developed to get an optimal or near-optimal solution using tabu search since the model is proven NP-hard. Example problems are tested to illustrate their procedure and performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.153-155
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• 2004

Various problems such as the increase of the power loss and the voltage instability may often occur in the case of low load power factor. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power a troublesome problem, so that the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is used for determining the locations of reactive power compensation devices effectively and for enhancing the load power factor appropriately. In addition, the integrated costs are used for determining the value of the load power factor from the point of view of the economic operation. It is shown through the application to a large-scale power system that the system power factor can be enhanced effectively and appropriately using the load power factor sensitivity and integrated costs.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.129-145
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• 2020

The article presents a systematic approach to design of marine navigation channels parameters resulting from manoeuvring and operational safety. Relations between the parameters of waterway system elements and the conditions of safe ship operation have been determined and the objective function of waterway parameters' optimization problems has been minimized with respect to variables of construction and operation costs. These costs have been functionally associated to variables of channel width at the bottom and fairway depth. The method of fairway's width computation at specified safe depth at the preliminary and detailed stages of waterway design has been proposed. The results of this method application have been illustrated with two examples: 1. The modernization of Szczecin-Swinoujscie fairway aimed at accepting vessels of 60,000 DWT capacity. 2. Construction of an approach channel leading to a newly built container terminal in Swinoujscie harbour (Poland), handling ocean-going container ships of 20,000 TEU capacity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권4호
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• pp.923-948
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• 2013

The main concern in mobile peer-to-peer (P2P) networks is security because jamming or eavesdropping on a wireless link is much easier than on a wired one and such damage can be incurred without physical access or contact. In particular, authentication has increasingly become a requirement in mobile P2P environments. This paper presents a new mutual authentication mechanism which requires less storage space and maintains a high level of security in mobile P2P networks. The proposed mechanism improves efficiency by avoiding the use of centralized entities and is designed to be agile in terms of both reliability and low-cost implementation. The mechanism suggested in the simulation evaluates the function costs occurring in authentication between the devices under mobile P2P network environment comparing to existing method in terms of basic operation costs, traffic costs, communications costs, storage costs and scalability. The simulation results show that the proposed mechanism provides high authentication with low cryptography processing overhead.