• 대한토목학회논문집
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• 제33권5호
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• pp.2081-2091
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• 2013

최근, 엔지니어링의 실무에서 토목 시설물의 설계 및 유지관리 단계를 위한 효과적인 생애주기비용(Life Cycle Cost; LCC) 산정 방법의 실무적인 적용에 대한 요구가 높아지고 있다. 이와 같이, 21세기에 들어 엔지니어링의 최적 의사결정의 실무적 문제에 가치공학과 더불어 생애주기비용 분석은 새로운 패러다임으로 주목받고 있지만 이러한 연구 개발의 괄목할만한 진보에도 불구하고, 대부분의 설계단계 생애주기비용 분석은 확정적, 확률적 분석기법에 그치고 있고 적용 가능한 구조물도 일반 교량에 국한되어 있다. 따라서 본 논문은 설계단계 생애주기비용 분석에 대한 실용적이고 합리적인 신뢰성해석 기반 성능저하 모델을 고려하여 기존의 분석방법을 업데이트하는 분석 방법론을 개발하고 이를 특수교인 사장교에 적용하는데 목적이 있다. 이에 현재가치의 합으로 표현되는 직/간접 유지관리비용을 기존 방법과는 다르게 기대 성능저하모델에 바탕을 둔 최적 유지관리 시나리오를 통한 생애주기비용 분석 기법으로 제시하였다. 마지막으로 본 논문에서 제안한 업데이트된 생애주기비용 분석의 방법론을 실제 고속도로 사장교 건설 프로젝트의 설계단계 의사결정 문제에 적용하여 합리적이고 체계적인 분석 방법 및 최적의사결정과정을 제시하였다.

• 대한토목학회논문집
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• 제35권1호
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• pp.93-99
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• 2015

본 연구는 RC 휨부재에서 동일한 안전율을 갖으면서 경제성을 확보할 수 있는 휨 철근비를 결정하는 방법에 관한 실용적 연구이다. 재료비 및 인건비를 고려하여 공사비 함수를 구성하였고, 최저공사비를 유도하는 경제적 휨 철근비를 결정하는 식을 제안하였다. 제안식을 통해 단철근보의 최적 철근비는 0.65~1.0%를 추천하였다.

• 대한산업공학회지
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• 제35권1호
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• pp.73-86
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• 2009

This paper discusses a method of determining the optimal design of a block. A horizontal layout of blocks is assumed in which transfer points are located at a side of the block. Each block has several transfer points (TPs) each of which is assigned to a group of adjacent bays and located at the center of the assigned group. The goal is to find the optimal size of a block and the optimal number of TPs while minimizing the total cost consisting of the fixed and operational cost of yard cranes (YCs), the operational cost of internal trucks, and the installation cost of TPs. Constraints on the maximum expected system time of trucks are imposed for the optimization. Formulas for estimating handling operation cycle times of a YC are derived analytically. Numerical experiments are conducted to illustrate optimal block designs for a given set of data.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.25-30
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• 1999

This paper covers the development of a highly portable and low cost SPOT image data receiving system. We followed two design approaches. One is the software-based approach by which most of the real-time processing is handled by software. With the complete software-based design, it is simple to add a function for receiving any additional satellite data. Satellite-specific format handlers including error correction, decompression and decryption can easily be accommodated. On the other approach. we used a general hardware platform, IBM-PC and a low cost SCSI RAID (Redundant Away of Independent Disks), and therefore, we can make a low cost system.

• 한국경영과학회지
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• 제22권3호
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• pp.23-36
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• 1997

In the design of telecommunication network, the network configuration using hubbing topology is useful for designing and managing the network efficiently : i. e. all of central offices (COs) are grouped into clusters. Each cluster has one hub consisting of large-scale transmission facilities like digital cross-connect systems and ATMs. In clustering process, the community of interest and geographical factor should be considered. However, there exists a tradeoff between two factors. One is to minimize total link costs for geographical factor and the other is to maximize the total intra-cluster traffics for community of interest. Hence, this can be solved by multiobjective linear programming techniques. In this paper, the problem under considerations is formulated as two p-median subproblems taking into considerations total costs and total intra-traffics, respectively. Then we propose the algorithm to solve the problem based on the concept of cost-traffic tradeoff. The algorithm enables to identify efficient cost-traffic tradeoff pairs. An illustration is also presented.

• 대한산업공학회지
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• 제32권2호
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• pp.104-110
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• 2006

When a new facility such as automobile assembly line is designed, computer simulation is often used to estimate its actual throughput level. If it falls short of the target throughput level, then the design must be modified to increase the throughput capacity. For complex facilities having parallel processes and network of material flows, the modification procedure is not trivial. Even if the capacity of a particular bottleneck process is increased, the target throughput may not be achieved because the bottleneck may move to another process. Furthermore, each process has a different set of options with different cost to increase the capacity. In this study, we present a systematic procedure of determining the cost-effective set of options which achieves the target throughput.

• 품질경영학회지
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• 제40권2호
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• pp.117-125
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• 2012

For the highly reliable products, an accelerated degradation test (ADT) is a useful tool which has been employed in industry to obtain reliability-related information within an affordable amount of time and cost. In an ADT, as all other reliability tests, it is important to carefully design the ADT beforehand to obtain estimates of the quantities of interest as precisely as possible. In this paper, optimal ADTs are developed assuming that the constant-stress loading method is employed and the degradation characteristic follows a Wiener process. Under the constraint that the total cost does not exceed a pre-specified budget, the stress levels, the number of test units allocated to each stress level and the number of measurement (termination time) are determined such that the asymptotic variance of the maximum likelihood estimator of the q-th quantile of the lifetime distribution at the use condition is minimized.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.518-525
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• 2009

The bi-directional high pressure pile load test(BDH PLT) which is a kind of pile load tests was conducted to find out a reasonable design procedure of large-diameter drilled shafts of large-size building structures. The behaviors of bearing capacity and settlement of the large-diameter drilled shafts were analyzed and the results obtained from BDH PLT were also compared with those obtained from the equations suggested in the specification. In case of the reasonable design procedure adopted, the construction cost could be saved at least 15 ~ 28%. It could be concluded that BDH PLT should be needed for the foundation construction cost reduction of the high-rise building structures.

• 산업경영시스템학회지
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• 제20권43호
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• pp.249-263
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• 1997

This paper addresses the parts route selection and economic design in flexible manufactuirng system (FMS). Parts are processed through several stage workstations according to operation sequences. The machine of each workstation can do multiple operation functions. And the operation stage of a part can be processed in several workstations, which are non-identical in functional performance. The objective of this paper is to determine the processing routes of parts, number of machine at each workstation, number of vehicle and makespan time. Two models are suggested. One is assumed that the operation stage of parts can be processed at the only one among several available workstations. Other is assumed that the operation stage of parts is allowed to be processed at several workstations. Parts are transported by automated guided vehicles (AGVs). The decision criteria is to minimize the sum of processing cost, travel cost, setup cost and overhead cost. The formulation of models is represented. A solution algorithm is suggested, and a numerical example is shown.

• 산업공학
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• 제14권2호
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• pp.205-209
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• 2001

The number of tunnel has fast increased with the rapid expansion of highway network. Tunnel should be designed to provide for drivers both safety and pleasant driving conditions. In this perspective, the design for tunnel lightning is very important in order to provide its safety, pleasantness, and cost-efficienty of maintenance, all of which should be considered and analyzed for a better tunnel lighting. This paper attempts to compare the low-pressure sodium lamp, which has usually been used for tunnel lighting, with the fluorescent lamp, which we consider as an alternative for the former. In an effort to determine the number of lamps to meet the required illuminance in the tunnel, this research employs a simulation technique which would allow us to conjecture, with the aid of basic model, the life cycle cost for illumination per each tunnel. This analysis is expected to provide a basic method and related information for tunnel development and design.