• Communications for Statistical Applications and Methods
• /
• v.17 no.6
• /
• pp.755-765
• /
• 2010

For classification problems on mixture distribution, a threshold based on cost functions is optimal from the viewpoint of a minimum expected cost. Assuming that there is no cost information, we propose cost ratios in the expected cost corresponding to thresholds where the total accuracy and the true rate are maximized to explain the relation of these cost ratios minimizing the expected cost. Other cost ratios are also proposed by comparing the normalized expected costs when classification accuracy is maximized. The values of these cost ratios are located between two cost ratios for the expected costs based on classification accuracies, and converge to that of the minimum expected cost. This work suggests two cost ratios: one is minimized by the expected cost and the normalized expected cost, and the other in the expected cost and the normalized expected cost functions that are maximized classification accuracies. We discuss their compatibility based on the relation of these cost ratios.

• Korean Journal of Construction Engineering and Management
• /
• v.9 no.6
• /
• pp.216-224
• /
• 2008

Recently, most developed countries use the evaluation system about Life Cycle Cost(LCC), and KOREA is beginning to introduce the system to reduce construction expenses. And the introduction of "Technical Proposal Type Bid", which is a new procurement method of Korea government, has made needs for the price-valuation way to evaluate facilities LCC. These days, LCC has been being evaluated by BTL and turnkey project in KOREA, which is suffering from difficulties in evaluating it, because evaluation elements and standards are vague. In addition, LCC evaluation in public construction business except BTL and turnkey is not carried out. Therefore, this paper is to develop a new evaluation index to evaluate LCC both systematically and objectively. The results of this paper are as followings. (1) Necessity and problem analysis of LCC evaluation index, (2) LCC evaluation index deduction from the technical report and question analysis, (3) Application and evaluation method suggestion to practice.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.733-739
• /
• 2011

B2S(Ballasted track To Slab track) that is track system has been first developed in 2004 with foundation of rich experience and know-how of subway track upkeep and mending of facilities in 36 years to improve an existence pebble track at a concrete track. 'B2S' is admitted technology through patent registration in the domestic and Europe and it's made by a factory and put together at field, so it's able to construct precisely and to reduce a construction period. In addition, safety, the ecological balance and durability are excellent, and walking, cleaning, etc. has the advantage of easy maintenance. 'B2S' is currently laying 27.7km at Seoulmetro as of end of 2010 standard, but it'll be expected to be applied to a domestic Metro more from now on. It is possible to classify the total cost resolution structure of B2S system by R&D cost, test production and experiment cost, the initial facility cost, maintenance cost, disposal cost. In this research, it seems useful for selection evaluation which considered the life cycle cost or economics of the concrete track structure by analyzing an initial cost of facilities.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.400-405
• /
• 2011

The total length of Korean urban railways reaches 1,200km. Urban railway used to be installed with ballasted tracks by reason of low cost at the time of construction, slab tracks are now being installed due to the reasons of the improvement in safety, lengthening service life and more economical method in terms of maintenance. The length rate of slab tracks has exceeded 70% of the domestic urban railways with the methods ranging from STEDEF, LVT, ALT, Eidan-type, B2S to RHEDA. This study surveyed the share of domestic slab tracks, and compared and evaluated the input cost at the initial stage by the types of slab tracks. Construction processes have been standardized by the existing design documents and calculated the initial input cost for the length of 1km of a hypothetical straight line. Cost breakdown structure was evaluated as materials cost, construction cost, equipment cost, indirect cost, etc. It is expected that this study will be used in selection & evaluation which is considering the economic feasibility of slab tracks.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2011.04a
• /
• pp.172-175
• /
• 2011

Financial supports for housing for the disabled is limited since a certain amount of budget needs to be distributed for a number of disabled families. Therefore, it is important to fund renovation for the disabled effectively and properly. Financial and administrative supports for the renovation which intended to improve housing conditions in terms of accessibility (barrier free) and comfort needs to be implemented with larger outcome and smaller budget. The purpose of this study was to investigate various factor such as renovation cost and renovation elements, influence satisfaction of residents with disabilities. Participants of this study are limited to the recipients of financial supports for housing renovation and refurbishment from City of Seoul and Ministry of Heal and Welfare. A total of 155 cases were analyzed using post occupancy survey and analysis of project cost data. Overall, more cost were used for modification for housing condition improvement than the cost for removal of architectural barriers. Renovation cost differences were not apparent among the type and extent of an individual's disabilities. Instead existing housing type and physical condition for the housing affects cost for renovation more significantly. Overall the renovation cost is positively related to resident's satisfaction using regression analysis.

• Korean Business Review
• /
• v.3
• /
• pp.183-210
• /
• 1990

In this study traditional depreciation method has been analysed carefully and then compared with the depreciation on current cost basis for the purpose of reviewing the basic theory underlying depreciation on current cost basis in view of the current situation demanding new method of depreciation. In this treatise the inevitability of rejecting the basic theory of depreciation and traditional depreciation method has been treated. Furthermore the probable consequence when such refutation of traditional depreciation occurs is studied. How to resolve such problems and what is the basis for claiming for depreciation on current cost basis have been also analysed. Through this analysis and research the following conclusions have been drawn: 1. For the purpose of complete recovery of invested capital depreciation on current cost basis is demanded. 2. For the purpose of undertaking realistic profit computation and accounting to apply to comparison and analysis of business operation depreciation on current cost basis is required. 3. When the feasibility of depreciation on current cost basis is guaranteed' then depreciation on current cost basis can be promoted. 4. Depreciation on current cost basis should be studied from the standpoint of evaluation position.

• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.3
• /
• pp.299-312
• /
• 2016

The main objective of this paper is to develop computer simulation program for performance evaluation and cost estimation of a reverse osmosis (RO) and pressure-retarded osmosis (PRO) hybrid process to propose guidelines for its economic competitiveness use in the field. A solution-diffusion model modified with film theory and a simple cost model was applied to the simulation program. Using the simulation program, the effects of various factors, including the Operating conditions, membrane properties, and cost parameters on the RO and RO-PRO hybrid process performance and cost were examined. The simulation results showed that the RO-PRO hybrid process can be economically competitive with the RO process when electricity cost is more than 0.2 $/kWh, the PRO membrane cost is same as RO membrane cost, the power density is more than $8W/m^2$ and PRO recovery is same as 1/(1-RO recovery).

• KIEE International Transactions on Power Engineering
• /
• v.5A no.3
• /
• pp.303-308
• /
• 2005

The restructure of the electrical power industry is accompanied by the extension of the electrical power exchange. One of the key pieces of information used to determine how much power can be transferred through the network is known as available transfer capability (ATC). The traditional ATC deterministic approach is based on the severest case and it involves a complex procedure. Therefore, a novel approach for A TC calculation is proposed using cost optimization in this paper. The Jeju Island interconnected HVDC system has inland KEPCO (Korean Electric Power Corporation) systems, and its demand is increasing at the rate of about $\10[%]$ annually. To supply this increasing demand, the capability of the HVDC system must be enlarged. This paper proposes the optimal transfer capability of the HVDC system between Haenam in the inland and Jeju in Cheju Island through cost optimization. The cost optimization is based on generating cost in Jeju Island, transfer cost through Jeju-Haenam HVDC system and outage cost with one depth (N-1 contingency).

• Journal of the Korean Solar Energy Society
• /
• v.31 no.3
• /
• pp.29-35
• /
• 2011

This study draws economic expense factors according to the influence of generation resulted from slipstream and the arrangement of the complex when arranging and designing the complex for offshore windpower development as a model of 50MW offshore wind farm and conducts economics analysis. According to the result of the analysis, O (Optimize) arrangement was the one that has the highest generation for having the best windpower resources in terms of design and being least affected by slipstream; however, the arrangement requires expensive submarine cables and high installation cost. Therefore, according to the analysis of economics, it was thought that 50MW complex should have less economics as BC ratio 0.95 than the series arrangement of main wind direction and I+80 series arrangement would be rather more economical. This economics evaluation provides comparison according to the arrangement of the development complex considering the uncertainty of the electricity price and gross construction cost. And it is expected that the result of economics evaluation would greatly differ by installation capacity, and the reason is that the cost of electric infrastructure takes up a higher portion than the gross construction cost of the development complex. The only way to compensate this part is to make the windpower development complex larger. It seems that it will be necessary to enhance spot applicability to evaluate economics afterwards and pay consistent attention to and conduct follow-up research on the economics evaluation of the complex construction.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.11 no.3 s.55
• /
• pp.11-21
• /
• 2007

Potential damage and losses associated with structural systems caused by earthquake can be reduced by application of seismic design to the structures. Because the building cost required for seismic design is generally higher than the cost for non-seismic design, the application of seismic design must be justified considering both seismic performance and cost. This paper presents a risk-based fiamework for evaluation and comparison of seismic performance of structures such that necessary data can be supplied for decision making on seismic design. Seismic fragility curve is utilized for seismic risk assessment of structures, and the process for decision analysis on adaptation of seismic design is presented based on the equivalent cost model.