• 한국IT서비스학회지
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• 제13권4호
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• pp.169-188
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• 2014

Recently the complexity and difficulty of the IT projects are increasing due to technological and environmental risks, resulting in the adoption of PMO(Project Management Office) onto IT project management practices, including public area projects. For example, the Korean government regulated the application of PMO onto large scale public IT projects. However, since there has been no reliable method to estimate the cost to execute PMOs, a PMO cost evaluation model to support the budget and cost planning of PMO projects is required. Thus, the purpose of this research is to develop a systematic cost evaluation model for PMO projects. We identified the dimensions that determine the PMO execution cost to be the scale of the subject project, the technical difficulty level of the subject project, and the tasks to be executed in the PMO project. Based on the determinants, the PMO execution cost model were developed from historical data and experts opinion. Upon verification, the validity of the developed model has high level of consistency compared with their experiences of real PMO project costs.

• 한국안전학회지
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• 제17권1호
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• pp.68-71
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• 2002

A research on accident loss calculation for polyol process without safety management activities, and safety cost estimation using process risk assessment has been implemented. In order to estimate a magnitude of loss, accident scenarios were made by combining result made from HAZOP Study method with accident possibility analysis results implemented with FTA. Also effect assessment was implement for accident consequence of each scenario. And minimum possible loss cost has been calculated when safety investment do or not. Result from cost-benefit analysis was shown as approximately \335 billion(=USS44,000 billion), as cost after subtracting safety management cost from minimum possible loss cost.

• Structural Engineering and Mechanics
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• 제33권5호
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• pp.561-572
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• 2009

Nowadays, Eurocodes have become the reference standards for silo design within the European Union. They include new procedures for load assessment and structural verifications aiming to design safer silos. However, many silo manufacturers are still reluctant to use them (or at least all their prescriptions) because of the loss of competitiveness they are experiencing in comparison with former standards. This paper shows how steel cost of flat-bottomed circular silos varies when different silo geometries and stored materials are considered. The influence of critical structural verifications on steel costs, such as buckling of the silo wall, were also analyzed and some conclusions and practical recommendations for silo designers were proposed.

• 한국안전학회지
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• 제24권6호
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• pp.79-85
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• 2009

This study presents an algorithm to select the best alternative plane among various bridge superstructure types(Steel box girder, Rational girder, PSC-I girder) using Value Engineering(VE). Economical efficiency, landscape, constructability, maintenance, stability, function of bridge superstructure were taken into consideration in the designing of bridge. Economical efficiency was evaluated for each alternative plan with optimal design considering Life Cycle Cost(LCC). Repair and rehabilitation histories and some factors were set to get reasonable results. In the application of Analytic Hierarchy Process(AHP), consistency of Pairwise Comparisons Matrix was evaluated and the best plan was determined.

• Structural Engineering and Mechanics
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• 제48권3호
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• pp.309-331
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• 2013

An integrated superelement concept is proposed to improve the computational efficiency when analyzing structural responses during progressive collapses of large-scale structures, such as multi-storey reinforced concrete buildings. While the proposed methodology is straightforward and can be implemented into an existing finite element program with little effort, it is able to significantly reduce the computational cost without the loss of any critical information of the structural responses. Compared with the models without superelement, significant saving in computational cost and satisfactory prediction accuracy can be obtained with the proposed approach.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.226-230
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• 2013

In the tall building construction, the slab formwork largely impacts on construction cost. Because productivity of a slab formwork is influenced by a number of and the efficiency of equipment, using the equipment-based construction method, an appropriate equipment input planning is crucial for the productivity. Meanwhile, the general equipment input planning is conducted by intuition based on experience due to the lack of equipment productivity data. Thus, this study develop a simulation model to analyze table formwork productivity and to propose an optimum equipment input plan that reflects the construction process, based on the full consideration of the economic factors. This study developed a simulation model by using CYCLONE and the data for the model was collected by measuring the duration of each unit activity in the tall building where table forms were applied. It is expected that a simulation model helps users to make better decision on the equipment input planning of slab formwork.

• 로봇학회논문지
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• 제7권2호
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• pp.150-159
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• 2012

In this paper, we propose a cost-aware Rapidly-exploring Random Tree (RRT) path planning algorithm for mobile robots. A mobile robot is presented with a cost map of the field of interest and assigned to move from one location to another. As a robot moves, the robot is penalized by the cost at its current location according to the cost map. The overall cost of the robot is determined by the trajectory of the robot. The goal of the proposed cost-aware RRT algorithm is to find a trajectory with the minimal cost. The cost map of the field can represent environmental parameters, such as temperature, humidity, chemical concentration, wireless signal strength, and stealthiness. For example, if the cost map represents packet drop rates at different locations, the minimum cost path between two locations is the path with the best possible communication, which is desirable when a robot operates under the environment with weak wireless signals. The proposed cost-aware RRT algorithm extends the basic RRT algorithm by considering the cost map when extending a motion segment. We show that the proposed algorithm gives an outstanding performance compared to the basic RRT method. We also demonstrate that the use of rejection sampling can give better results through extensive simulation.

• 대한토목학회논문집
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• 제33권2호
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• pp.781-790
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• 2013

본 연구에서는 평균건설단가를 적용하여 개략 공사비를 산출하는 기존 방식에서 벗어나 대표공종을 이용한 입력변수 도출 모델을 구축하여 기본설계단계에서 고려되어지는 여러 입력변수들을 활용하여 P.S.C(Prestressed Concrete) Box Girder 교량에서 널리 활용되고 있는 I.L.M(Incremental Launching Method) 공법에 연구 모델을 적용하고자 한다. 2000년부터 설계된 공사비 데이터와 설계자료 등을 분석하여 상부공사 중 총 공사비대비 누적비율 95%이상을 차지하는 공종을 대표공종으로 도출하였다. 각 대표공종의 하위공종에 대한 내역 분기를 실시하여 각 항목들의 Database를 구축하였다. 본 연구에서는 다각적인 측면에서 개략공사비 산정 모델을 개발 및 제시하였으며, 사용자 입장에서 보다 쉽게 접근할 수 있도록 대표공종을 기초로 단위물량을 사용한 개략공사비 산정모델(I)과 상관성이 높은 입력변수를 선택한 개략공사비 산정모델(II)과 상관계수 0.6이상의 입력변수들을 모두 포함하는 다중회귀분석을 통한 개략공사비 산정모델(III)을 제시한다. 실제 총공사비와 본 연구에서 제시하는 개략공사비 산정모델들을 비교하고, 신뢰성을 검증함으로써 현재 국내에서 사용되는 산정방법에 비해 정밀도 측면에서 효율적인 공사비 관리방법을 제시한다.

• 한국환경복원기술학회지
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• 제25권4호
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• pp.15-31
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• 2022

The Green Purification Unit System (GPUS) is a green infrastructure facility applicable to the roadside to reduce particulate matter from road traffic. This study introduces two types of GPUS (type1 and type2) and assesses the performance and maintenance costs of each of them. The GPUS's performance analysis used the data collected in November 2021 after the installation of the GPUS type1 and type2 at the study site in Suwon. The changes in the particulate matter concentration near the GPUS were measured. The maintenance cost of GPUS type1 and type2 was assessed by calculating the initial installation cost and the management and repair cost after installation. The results of the performance analysis showed that the GPUS type1, which was manufactured by combining plants and electric dust collectors, had a superior particulate matter reduction performance. In particular, type1 produced a greater effect of particulate matter reduction in the time with a high concentration (50㎍/m³ or higher) of particulate matter due to the operation of electric dust collectors. GPUS type2, which was designed in the form of a plant wall without applying an electric dust collector, showed lower reduction performance than type1 but showed sufficiently improved performance compared to the existing band green area. Meanwhile, the GPUS type1 had three times higher costs for the initial installation than GPUS type2. In terms of costs for managing and repairing, it was evaluated that type1 would be slightly more costly than type2. Finally, this study discussed the applicability of two types of GPUS based on the result of the analysis of their particulate matter performance and maintenance cost at the same time. Since GPUS type2 has a cheaper cost than type1, it could be more economical. However, in the area suffering a high concentration of particulate matter, GPUS type1 would be more effective than type2. Therefore, the choice of GPUS types should rely on the status of particulate matter concentration in the area where GPUS is being installed.

• Computers and Concrete
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• 제12권6호
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• pp.755-774
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• 2013

Considering the well known environmental issues of cement manufacturing (direct and indirect levels of $CO_2$ emissions), clinker replacement by supplementary cementing materials (SCM) can be a very promising first step in reducing considerably the associated emissions. However, such a reduction is possible up to a particular level of SCM utilization, influenced by the rate of its pozzolanic reaction. In this study a (4-step) structured methodology is proposed in order to be able to further adjust the concrete mix design of a particular SCM, in achieving additional reduction of the associated levels of $CO_2$ emissions and being at the same time accepted from a derived concrete strength and service life point of view. On this note, the aim of this study is twofold. To evaluate the environmental contribution of each concrete component and to provide the best possible mix design configuration, balanced between the principles of sustainability (low environmental cost) and durability (accepted concrete strength and service life ). It is shown that such a balance can be achieved, by utilising SCM by-products in the concrete mix, reducing in this way the fixed environmental emissions without compromising the long-term safety and durability of the structure.