• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6B
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• pp.623-629
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• 2009

In this research, the process of developing software products to users in transfer by considering the warranty period to determine the timing of the release period is a comparative study of models. For the results of demonstration, exponential software reliability model increases the warranty period, the higher the initial period, but shows almost a similar release. In contrast, the optimal release time of imperfect debugging software reliability model, lower the initial warranty period, but the pattern is expected to rise slightly larger. The proposed model, extreme value distribution model, pattern of the optimal release time gradually increase, have a form that can be drawn. These research results through, warranty period and release the software developers understand the relationship between the optimal time for software development by using advance information could do is feed.

• International Journal of Human Ecology
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• v.6 no.1
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• pp.17-28
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• 2005

This study examines factors determining contemporary Chinese households' food away from home (FAFH) expenditures using Becker's household production theory. Data came from the 2000 urban household survey in Guangdong Province, collected by National Bureau of Statistics (NBS) of China. It was revealed that the contemporary urban Chinese wives also substitute their household work by time-saving product, FAFH, as Becker's household production theory postulated. This suggests the important role of time-value (opportunity cost) in determining household FAFH expenditure across the cultures.

• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.239-250
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• 2014

The purpose of this research is to implement and develop the Economic Cost Driver Size(ECDS) extended model to determine the optimal cash driver size with measurement complexity cost and allocation fail cost. ECDS model can be used to seek both measurement accuracy and time efficiency of the Activity-Base Costing (ABC). The study also develops Activity Priority Number (APN) to evaluate the importance of nonvalue-added activities improvement and to determine the representative cost driver of value-added activities when applying ECDS model. APN consists of Severity Priority Number (SPN), Undetectablitiy Priority Number (UPN) and Occurrence Priority Number (OPN). APN can be obtained from lower-stream activity, current activity, upper-stream activity in terms of hierarchical dependency of SIPOC (Supplier, Input, Process, Output, and Customer). In order to seek both efficiency of invested capital and reduction of overhead cost, the paper proposes the integrated ABC and Economic Value Added (EVA) model using redesigned ABC-based statement of comprehensive income and EVA-based statement of financial position. For a better understanding of the proposed ABC-EVA integrated model, numerical examples are demonstrated in this paper. Cost drivers of ABC and capital drivers of EVA in the proposed model can be used to reduce activity overhead cost from ABC-based statement of comprehensive income and to lessen activity capital charge from EVA-based statement of financial position.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.274-277
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• 2006

The EAC(Estimate at Completion) among existing methods, which estimate cost and time effectively, help managers anticipate changeable several results at the point of $15{\sim}30%$ in the project progress. However, this method may cause such some problems as not to consider the periodically changing circumstances caused by construction risks or uncertainties which can affect the cost and time in the project, and to regard collected and accumulated data only as a single value when predicting the results on the progress. Accordingly, it is very difficult to accept the even small range of variability based on the anticipation of EAC. Consequently, the study focuses on the possibility methodology to anticipate time and cost accurately on the way to utilize EVMS(Earned Value Management System), and also suggest the way to perform the right estimation of EAC as considering various risks and uncertainties in construction projects.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.456-459
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• 2002

It is lately issued studies on EVMS(Earned Value Management System) throughout construction industry, which is management system integrating cost and schedule effectively. So identifying importance and circumstance of introducing EVMS, CPI(Cost Performance Index) and SPI(Schedule Performance Index), which are critical components on schedule introducing EVMS, calculate and it intends to analyze the trend and problem of cost and time throughout project management, applying various statistical data analysis method.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.259-262
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• 2015

Due to the labor-intensiveness, high investment cost, long execution time, frequent change orders, and many stakeholders in a BIM project, a BIM manager is bound to face a lot of risks to make decisions in cost managing process. Since the productivity of a BIM team will affect the execution cost, this study investigates a simple method of assessing the productivity of a BIM team using the working timesheet records of the team. In this research, the productivity of a BIM team is defined as the effective working floor area (in square meters) of BIM uses per labor-time (in man-months) spent by the team. After the applicability of this method is tested by regression analysis using data from 5 real BIM projects in the construction phase, it is found that the simple productivity definition adopted in the method, although easy-to-implement, does not produce a statistically constant productivity value. More research is therefore needed in the future to devise better indicator(s) for assessing the productivity of a BIM team.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.542-549
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• 2005

Naval ships are complex weapon systems which play the integrated performance by system integration of many kinds of weapon systems and their leading ships are usually not disposed after test and evaluation but militarised. Then, strict project management is required for naval ship building projects by identifying problems early and by taking prefer measures in time against unexpected situations encountered in the process of the projects. EVMS is a project management system which can manage the schedule and the budget of a project concurrently and estimate the project's time duration and the cost at project completion. In this paper, the applicability and usefulness of WMS is studied for a assumed navai ship building project, in the environment of monetary fluctuations such as price index, wage increase rate and exchange rate.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.263-268
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• 2005

Nowadays, the vessel size is tending to be bigger and bigger, so port facilities are following this trend, which has been shown inthe competition of Hub-Port among the main ports such as Port of Busan and Port of Shanghai. But there are limited numbers of large container vessels and $70\%$ of the call ships at Busan port are middle and small sized ships which are less than 20,000ton. So we need to consider the handling facilities for these sized ships, but it has disregarded. In this paper, we estimate the optimum level of crane and labor according to vessel's size by container handling cost value reflecting size of vessel; size and number of crane and labor structure.

• Communications for Statistical Applications and Methods
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• v.15 no.6
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• pp.909-923
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• 2008

This paper considers the replacement model and the preventive maintenance model following the expiration of combination warranty for a repairable system. If the system fails after the combination warranty is expired, then it is minimally repaired at each failure. The criterion used to determine the optimal replacement policy and the optimal preventive maintenance policy is the overall value function based on the expected cost rate per unit time and the expected downtime per unit time. The numerical examples are presented for illustrative purpose when the failure time follows a Weibull distribution.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1528-1533
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• 2009

Infrastructure is provided to the user through long-term project period and large-scale working expenses. Existing facilities are getting old as time goes by. Accordingly, proper maintenance is required and generally more maintenance cost than initial invested cost is needed during life cycle. Therefore, a specific plan that just increases the value of facilities is required by evaluating performance of facilities and inputting minimum maintenance cost. Value engineering that increases the value of object by systemically analyzing Life Cycle Costs and function is actively promoted at the design phase of construction. These efforts can increase the performance of facilities at the maintenance phase of infrastructure. This study is to search how to evaluate the performance of Roadway by utilizing function analysis, as a core part of VE in the maintenance phase. In order to this a new evaluation criteria were proposed by adding an evaluation items to the existing criteria through the research of old documents, status of roadway maintenance and function analysis of VE. The results of this study may promote the effective performance evaluation to determine a resolution of roadway congestion in future. A succeeding study using the proposed evaluation criteria will be required.