• Journal of Digital Convergence
• /
• v.10 no.2
• /
• pp.171-182
• /
• 2012

The many companies and developers develop new mobile applications for serving to users. But, most of it is disappeared in a brief. Because Many applications weren't satisfy the needs of user. In this paper, it analysis to reason short life of mobile application in the smart terminals and mobile applications. Therefore, we develop dynamic user usability analysis system of applications to solve the problem. User usability analysis method is surveyed users and masters at present and then occurs high cost. In this paper, we develop dynamic user usability analysis system for real users. If usage of mobile applications upgrading, benefit of developers increased and serviced target contents to users.

• Economic and Environmental Geology
• /
• v.42 no.2
• /
• pp.133-141
• /
• 2009

For economic impact analysis on a R&D project of high-yield groundwater development in Jeju conducted by KIGAM from 2004 to 2007, benefit/cost ratio(BCR), net present value(NPV), and internal rate of return(IRR) were calculated by contingent valuation method(CVM), production function analysis, domestic water market analysis and technology factor analysis. Measurable direct impact parameters among the major outputs of this R&D project consisted the estimation 4 high-yield and high mineral groundwater reserve in Jeju. Annual use of the reserve by piped water and bottled water was estimated as 12.23 million ton and its monetary value was calculated as 293.4 million dollar in 2006 year value applied of 5.5% discount rate. Economic impact of this R&D project in NPV of year 2006, with applying a discount rate of 5.5%, was identified and estimated as 13.66 million dollar in NPV, 4.05 points in BCR, and 22.74% in IRR, respectively. Additional early launch benefit was 5.58 million dollar. Even increased of the 1% discount rate, NPV of this R&D project was also positive as 12.18 million dollar and BCR was 3.71.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.5
• /
• pp.960-967
• /
• 2009

Power supply system of electric railway has a diversity of safety problems since it should supply high electric power to the trains moving high speed with a lot of passengers on board. This paper provides a risk assessment approach to safety management of the electric railway facilities. Construction of database from field accident information, risk assessment and management of the risk are carried out systematically to ensure the safety. The risk assessment includes hazard identification, cause analysis by FTA(Fault Tree Analysis), consequence analysis by EVA(Event Tree Analysis), and loss analysis. In terms of the severity and the probability of the accidents deduced by these analyses, the risk of the accidents is assessed by using a risk matrix designed for electric railway facilities. Based on the risk assessment, possible risk mitigation options are identified and evaluated by analyzing their impact on the risk reduction and their cost benefit ratio. The long-term safety of the electric railway facilities can be ensured by renewal of the risk assessment and the risk mitigation option analysis with continuous accident database update. The proposed approach is applied to the electric railway facilities of Korean railway based on the accident data from 2002 to 2008.

• Journal of Navigation and Port Research
• /
• v.34 no.3
• /
• pp.213-220
• /
• 2010

Following the application of Formal Safety Assessment(FSA) to bulk carriers, crude oil tankers and large passenger ships, an urgent need to consider the safety of general cargo ships has recently been raised through the International Maritime Organization(IMO)(IMO, 2006a), and related FSA studies are being carried out by International Association of Classification Societies(IACS) as a preparatory work for the discussion on the issue of general cargo ship safety in the IMO committee. FSA is a structured and systematic methodology which is based on the techniques of risk analysis and cost benefit assessment to assist in the decision-making process, and aims at enhancing maritime safety, including protection of life, health, the marine environment and property. FSA can be used as a tool to facilitate the development of regulatory changes equitable to the various parties, with a view to aiding the achievement of consensus, and to help in the evaluation of new regulations and in making a comparison between existing and possibly improved regulations(IMO, 2007). This study aims at verifying the usefulness of FSA methods as a tool to conduct a safety assessment of general cargo ships flying the Korean flag, and providing useful information on 'the safety of general cargo ships' for IMO committee's discussion on the matter at a future session. FSA comprises five steps, however, steps 1(Hazard identification) and 2 (Risk analysis) from the FSA study for the Korean-flagged general cargo ships are discussed in this paper.

• Journal of Biomedical Engineering Research
• /
• v.28 no.3
• /
• pp.355-362
• /
• 2007

Diabetes mellitus can cause devastating complications, which often result in disability and death, and diabetic nephropathy is a leading cause of death in people with diabetes. In this study, we tried to predict the onset of diabetic nephropathy from an irregular and unbalanced diabetic dataset. We collected clinical data from 292 patients with type 2 diabetes and performed preprocessing to extract 184 features to resolve the irregularity of the dataset. We compared several feature selection methods, such as ReliefF and sensitivity analysis, to remove redundant features and improve the classification performance. We also compared learning methods with support vector machine, such as equal cost learning and cost-sensitive learning to tackle the unbalanced problem in the dataset. The best classifier with the 39 selected features gave 0.969 of the area under the curve by receiver operation characteristics analysis, which represents that our method can predict diabetic nephropathy with high generalization performance from an irregular and unbalanced dataset, and physicians can benefit from it for predicting diabetic nephropathy.

• Journal of Climate Change Research
• /
• v.6 no.2
• /
• pp.73-85
• /
• 2015

With 12 environmental basic facilities (EBF) in Busan, each business place's present situation of the operation of new and renewable energy as well as the feasibility to establish additional systems of utilizing solar energy (photovoltaic power generation system [PPGS] and solar heating system [SHS]) were investigated. Currently, with the environmental basic facilities, the new and renewable energies (such as, waste heat, biogas, PPGS, SHS, and small hydro power) can produce 195 GWh per year as electric power unit. Among the energy sources, except waste heat, biogas (154 GWh/yr) appears as the highest. Next, PPGS is the second most widely used system and produces 5,560 MWh/yr at 11 business places. Through a field survey, it appears that 19 business places of total 27 places at 12 EBFs have good locational conditions and they need an introduction of PPGS. Through it, it is investigated that it would be possible to produce 5,311 MWh/yr and to reduce $2,348tCO_2/yr$. And, it is identified that SHS can be additionally introduced in only 4 EBFs. This can reduce energy cost as much as one ten million won/yr and green-house gas as much as $28tCO_2/yr$. A cost-benefic analysis shows that the use of governmental support or private investment can be the most efficient way, when PPGS and SHS are introduced in EBFs.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.1
• /
• pp.49-55
• /
• 2010

The objectives of this study are to analyze the energy independence plan and to propose a suitable sewage treatment plant in Korea. The total amount of electricity consumption for public sewage treatment plant was estimated as 1,812 GWh in 2007. It was estimated that total 16 sewage treatment plants with renewable energy systems produced electricity of 15 GWh per year, which could replace 0.8% of total electricity used for sewage treatment. It was found that domestic sewage treatment plants with power generation plants by digestion gas were installed in 7 places and produced electricity of 13 GWh per year. It was also found that the power generation plants by digestion gas were the most cost-effective for sewage treatment plant out of the renewable energy systems based on the benefit-cost analysis.

• Journal of Applied Tourism Food and Beverage Management and Research
• /
• v.9
• /
• pp.213-242
• /
• 1998

Even in the best of economic environments, restaurants menu pricing is a serious concern to those in the food service industry. During times of rapid inflation, closer government regulation of compensation practices, and limited gains in worker productivity, the decisions regarding the proper charge for menu items become increasingly important. In addition to many operational and managerial factors, an important ingredient in the food service enterprise's success is its ability to meet the market by providing the value expected. The contribution-margin approach to pricing described above is familiar to cost accountants, who will also recognize that it admits of much elaboration before it can become a tool for day-to-day decisions. But the system probably has the greatest promise for multi-unit companies, where the cost benefit ratio of additional refinements improves in proportion to the number of operations. For example, the analysis required to specify the demand function better becomes less expensive if the findings can be applied to the pricing structure of numerous units. In any of its many adaptations, the essence of the integrated menu pricing system remains its ability to bring together the relevant revenues and costs with the operator's sense of the market and competitive environment to suggest prices that maximize profits.

• Management Science and Financial Engineering
• /
• v.10 no.1
• /
• pp.25-41
• /
• 2004

There have been many studies to build a model that can help investors construct optimal portfolio. Most of the previous models, however, are based upon the path-breaking Markowitz model (1959) which is a quantitative model. One of the most important problems with that kind of quantitative model is that, in reality, most of the investors use not only quantitative, but also qualitative information when they select their optimal portfolio. Since collecting both types of information from the markets are time consuming and expensive, making a set of target assets smaller, without suffering heavy loss in the rate of return, would attract investors. To extract only desired assets among all available assets, we need knowledge that identifies investors' preference for the risk of the assets. This study suggests two-layer decision-making rules capable of identifying an investor's risk preference and an architecture applying them to a quantitative portfolio model based on risk and expected return. Our knowledge-based portfolio system is to build an investor's preference-oriented portfolio. The empirical tests using the data from Korean capital markets show the results that our model contributes significantly to the construction of a better portfolio in the perspective of an investor's benefit/cost ratio than that produced by the existing portfolio models.

• Journal of the Korean Solar Energy Society
• /
• v.32 no.2
• /
• pp.11-18
• /
• 2012

Diesel fuel is expensive because transportation to remote areas adds extra cost, and it causes air pollution by engine exhaust. Providing a feasible economical and environmental solution to diesel generators is important. A hybrid system of renewable plants and diesel generators can benefit islands or other isolated communities and increase fuel savings. Renewable energy is, however, a natural source that produces a fluctuating power output. In this paper, hybrid power system of the marado lighthouse is proposed to supply stable power in the stand-alone hybrid power system. The proposed hybrid power system consists of the diesel generator, wind turbine, photovoltaic, fuel cell, and battery bank. To decrease the carbon emissions and find the optimization, the cost analysis of hybrid system is simulated using HOMER program and the optimized hybrid power system is designed.