• Journal of Integrative Natural Science
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• v.9 no.3
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• pp.206-214
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• 2016

The basic goal of software development is to produce high quality software at low cost. Therefore, when to stop software testing and release the software product is a significant point in the software development. The software cost model is an effective tool used to help software developers control costs and determine the release time. In this paper, we discuss the cost model to apply all 6 models with consideration of time to remove errors, cost of removing each error and risk cost due to software failure. We show the impact of cost coefficients and parameter values on the expected total cost by changing the values and comparing the optimal release times.

• Journal of Gifted/Talented Education
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• v.23 no.1
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• pp.49-65
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• 2013

The purpose of this study is to investigate the longitudinal impact of the engagement of private tutoring on student achievement and the influence of the engagement of gifted education on the effect of private tutoring by applying hierarchical linear growth modeling technique on the KELS (Korean Education Longitudinal Study) data. For the analysis, we used KELS data including the score of Mathematics achievement from 2005 to 2007 in order to get useful variables like whether or not to engage private tutoring, weekly time and monthly cost of private tutoring, the experience of gifted education, gender, prior achievement of 6th grade, parents' monthly income, internal motivation and self-efficacy. The sample consisted of 4,435 7th graders from Korean middle schools who were included in the KELS and have the data available to a significant dataset having no missing values include. The result suggest that the private tutoring experience predicted students' high Mathematics achievement and the interaction between grade and private tutoring time and cost has negative impact on the mathematics achievement. In contrast, it was found that the experience of gifted education has negative impact on the growth of mathematics achievement, but positive impact on the effect of private tutoring cost on the mathematics achievement. In other words, the experience of gifted education shows affirmative impact on the effect of private tutoring cost on the mathematics achievement indirectly. On the basis of this results, we discussed deeply the effect of private tutoring on the Mathematics achievement and the influence and its meaning of the experience of gifted education on the effect of private tutoring.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.598-603
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• 2002

The floor impact noise in apartment buildings has been known as the most sensitively recognized environmental noise. Therefore. inhabitants perceptual evaluation of floor impact noises was investigated by a questionnaire survey. It was found that the respondents perceive the floor impact noises from the upper nor as a constant noise level. However, if there is any child on the upper floor. the respondents felt Its noise as a harshly grating level. It was also found that the larger the respondents house is. the higher their wanted level of noise isolation is. Moreover, it was revealed that the main source of the floor impact noise from the upper floor is a child at the age from six to seven. The results could be used as fundamental data for the research on impact sources and new regulations that fit to Korean perceptual aspects and characteristics.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.217-224
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• 2002

This paper is proposed a reasonable method for determining the dynamic properties, the impact factors caused by traffic loads on highway bridges. In addition, the impact factors obtained in previous inspection reports were classified by the span length of the bridge, kind of bridge and type of bridge and the result of the impact factor was adjusted by a statistical method and presented problems. Also, the method for determining the impact factor using traffic load is proposed and the proposed method is compared with the specification code. The method estimating the impact factors due to the traffic loads can efficiently recognize the response of the structure by providing the impact factors and help to save the investigation cost, and also it can be used for the maintenance of structures using the usual test of bridges.

• Journal of Advanced Navigation Technology
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• v.16 no.6
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• pp.1065-1079
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• 2012

This research is done with the objectives to examine and to identify how the main factors of airline services, which become fundamentals for airline customers to select their favorite one, affect their customer satisfaction and their customer preference, with a focus on adjustable influence of converting cost. The survey has been conducted with the population of the airline customers who use international airlines through Incheon International Airport and processed with the objectives to verify the influence of the main factors of airline services to customer satisfaction and customer preference and also to collect the verified data for adjustable influence of converting cost between customer satisfaction and customer preference, and its results are as follows: Firstly, airline services have significant impact on their customer satisfaction. Secondly, they also have significant impact on their customer preference, Thirdly, the converting cost between both of customer satisfaction and customer preference to airline services doesn't involve the adjustable function in consecutive cost nor in learning cost but it does involve the one in sunk cost.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.8
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• pp.1209-1215
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• 2015

Since lamb is a commodity, producers cannot control the price of the product they sell. Therefore, managing production costs is a necessity. We explored the study of elasticities as a tool for basing decision-making in sheep production, and aimed at investigating the composition and elasticities of lamb production costs, and their influence on the performance of the activity. A representative sheep production farm, designed in a panel meeting, was the base for calculation of lamb production cost. We then performed studies of: i) costs composition, and ii) cost elasticities for prices of inputs and for zootechnical indicators. Variable costs represented 64.15% of total cost, while 21.66% were represented by operational fixed costs, and 14.19% by the income of the factors. As for elasticities to input prices, the opportunity cost of land was the item to which production cost was more sensitive: a 1% increase in its price would cause a 0.2666% increase in lamb cost. Meanwhile, the impact of increasing any technical indicator was significantly higher than the impact of rising input prices. A 1% increase in weight at slaughter, for example, would reduce total cost in 0.91%. The greatest obstacle to economic viability of sheep production under the observed conditions is low technical efficiency. Increased production costs are more related to deficient zootechnical indexes than to high expenses.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1165-1171
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• 2015

Due to the increasing trend of operation and maintenance cost (O&M cost) of infrastructure, the accurate estimation of O&M cost is crucial part to the government. Recent literatures pointed out that gradual climate changes such as average temperature changes, average precipitation changes, and etc. have significant impact on infrastructure O&M cost. This research is intended to develop a long-term O&M cost prediction model of road facilities by considering the impacts of average temperature changes. For this end, the climate change scenarios of Intergovernmental Panel on Climate Change (IPCC)'s $5^{th}$ report are adopted to structure the impact of average temperature changes by using binomial lattice model. The proposed framework is expected to regional government in supporting decisions for road O&M cost.

• Journal of Environmental Impact Assessment
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• v.7 no.1
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• pp.109-116
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• 1998

As of July 1997, the registered number of automobiles exceeded 10 million and Korean auto industry produced 2,850,000 cars. Many environmentalists warn that the passenger cars are not sustainable urban transportation system in large cities. The cars produce about 80% of air pollutants, and consume 30% of petroleum imported. For the past 30 years the administration increased the road system, but the length of road per car is decreased from 813m in 1965 to 9m in 1995. The cost of traffic congestion was estimated to be \14.7 trillion in 1996, and is feared to increase without changing the present transportation system. The undesirable impact of cars include the casualties from traffic accidents, insurance loss, and separation of human relatioships. To construct sustainable urban transportation system, three principles should be followed. The first principle is to make the urban streets walkable for the people. The second principle is to encourage bicycling. Roads and traffic systems should be designed to let bicylces travel safely. The third principle is to supply more buses and construct integrated transportation system based on buses. The subway system is too expensive to construct and without the support of a well-organized bus system it may not work efficiently. The Brazilian city of Curitiba has constructed a very efficient bus system only with 1/80 of the estimated cost of subway system. The car-oriented transportation system does not seem to be an envrironmentally sustainable transportation system in most of the Korean cities.

• Journal of Environmental Impact Assessment
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• v.14 no.6
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• pp.443-453
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• 2005

For the purpose of the comparative environmental estimation of the incineration processes for domestic wastes, environmental impacts for several incineration processes for one ton of domestic wastes have been estimated by employing life cycle assessment as the environmental impact assessment method. The scheme of minimum production of environmental pollutants has been considered for three different incineration processes. The evaluation for latent influence on environment was carried out by using CML(Center of Environmental Science) method which was developed by University of Leyden in Netherlands based on the equivalency factor suggested by Korea Accreditation Board. The result of life cycle assessment has showed that the total cost analysis according to the amount of incinerating waste was dependent on the operating conditions of incineration process. In addition, the annual running cost for the incineration of one ton of wastes was estimated to be negatively dependent on the amount of wastes. The degree of environmental pollution was mainly due to the kinds of the wastes rather than by the amount of wastes.

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.271-279
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• 2015

Global warming has pressured companies to put a greater emphasis on environment management which allows them to reduce environmental impact and costs of their operations. In Korea, the coal-fired power plants take a large account of electricity generation at 31.7% of the total electricity usage in 2014. Thus, environmental impact of coal-fired power plants is significant. This paper illustrated how to compute environmental impact and costs in electricity generation at a coal-fired power plant using MFCA methodology. Compared to the traditional accounting, an advantage of MFCA is to provide information on electricity generation costs and environmental wastes incurring throughout the production process of electricity. Based on MFCA, the coal-fired power plant was able to reduce production cost of electricity by 52.3%, and environmental wastes by 47.7%. As a result, MFCA seemed to be an effective tool in environmental management for power plants.