• Applied Chemistry for Engineering
• /
• v.23 no.3
• /
• pp.297-301
• /
• 2012

Microbial fuel cell (MFC) is the major of bio-electrochemical system which can convert biomass spontaneously into electricity through the metabolic activity of the microorganisms. In this study, we used an activated sludge as a microbial inoculum and then investigated the feasibility of using dairy wastewater as a possible substrate for generating electricity in MFC. To examine the performance of MFC as power generator, the characteristics on cell potentials, power density, cyclic voltammetric analysis and sustainable power estimation were evaluated for dairy wastewater. The maximum power density of $40\;mW/m^2$was achieved when the dairy wastewater containing 2650 mg/L COD was used, leading to the removal of 88% of the COD. The results from this study demonstrate the feasibility of using MFC technology to generate electricity while simultaneously treating dairy wastewater effectively.

• Journal of Navigation and Port Research
• /
• v.30 no.8 s.114
• /
• pp.617-622
• /
• 2006

Gamcheon Harbor was developed to cope with increased freight demand of Busan port and supplement function of the north port. Because container wharf is opened to 1997 as well as general wharf, present maximum 50,000DWT class containerships have been incoming and outgoing. However, In Gamcheon port, small size ships such as fishing boats, miscellaneous boats account for 50 percent of the traffic and a public marine products wholesale market that is building on the north wharf will open in 2008. Therefore, it needs to grasp future year traffic volume before establishing operation plan for port management. Also, analysis on crossing situation risk is required because the breakwater entrance in Gamcheon Harbor is narrow and the crossed passing of ship is ever-present at breakwater front. Thus the traffic volume in the future was presumed and quantitative analysis was achieved on crossing situation though simulations with the traffic volume.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.20 no.1
• /
• pp.26-33
• /
• 2012

Competition between air transportation and railways has grown fiercer in major countries around the world with the rise of high-speed railways. In South Korea, air passenger travel has been rapidly decreasing since the initial launch of the Seoul-Pusan KTX line in 2004 and second opening that followed in 2010. Further expansion of the high-speed railway is expected. At present, research efforts to verify the validity of constructing an underwater express railway tunnel between Ho-nam and Jeju Island are taking place. Considering the possible high speed railway connection between Seoul and Jeju Island, this thesis has analyzed the choice behavior of existing passengers of the major and low-cost carriers. For this, Stated Preference (SP) research has been performed for three variables, including fare, travel time and the number of runs, to estimate the substitution rate of each of the three variables. Binomial Logit Model has been estimated with the obtained data. The estimation of the model has found that airline passengers of major and low-cost carriers are willing to pay approximately 7,200 KRW and 5,000 KRW, respectively, to reduce travel time by one hour. If the number of runs in one day increases, it has been estimated that the passengers are willing to pay additional fares of about 390 KRW and 30 KRW, respectively. On the other hand, the substitution rate between the number of runs and the travel time was found to be somewhat insignificant. If the construction of the Seoul-Jeju line progresses in the future, this study could be used as preliminary data for determining fares, travel time and the number of runs.

• Health Policy and Management
• /
• v.16 no.1
• /
• pp.95-116
• /
• 2006

According to rapid increase of the population of senior citizens, there has been growing concern of Long-Tenn Care(LTC) services recently. Long-Tenn Care services, however, haven't been established systematically in Korea and the supply of LTC services is not sufficient despite the increase in the current social demand. This study aims to estimate the 'Willingness to Pay(WTP)' for LTC insurance which the government plans to introduce by means of social insurance, using Contingent Valuation Method(CYM). In addition, this study analyzes the factors affecting WTP for LTC insurance. An interview survey was carried out to derive WTP for LTC from 450 people who lived in Seoul aged 20 and above during the period from 16th to 21st of June 2003. Double-Bounded Dichotomous Choice Method was applied among several CVMs available to estimate both use value and no-use value of goods. There was pilot survey carried out prior to the main survey. The results show that the average monthly. WTP for LTC provided in home and residential setting is 18,192Won and 19,293Won, respectively. In the case of home care, WTP goes higher depending on reliability of LTC insurance policy and need for LTC insurance, as well as marital status, education and average monthly income. On the contrary, WTP is conversely affected by higher age and higher bids. In the case of institutional care, the factors affecting WTP are similar to those of home care, except age. This study followed NOAA's suggestions generally and the value derived through survey could be reliable. However, there can be the least bias in the process of survey because the CVM should be used under the supposed circumstances. Despite those limitations, it can be concluded that the amount the citizens are willing to pay for LTC is high enough to meet the costs needed to provide LTC.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.321-326
• /
• 2001

Current situations, such as IMF crisis, WTO agreement and decrease of construction market, demand changes to construction companies. To meet the situation, they focus on the value of the intangible assets to improve their competitive power. In Korea, Various institutes estimate the construction company in accordance with their Purposes. But their estimating method has limitations to know the potential value of the company because they don't much concentrate on characteristics of construction industry and intangible assets. This study was peformed to introduce the methodology of estimating intangible assets of company and to show the state of intangible asset of major construction companies in Korea. Market Capitalization Method(MCM) was used to calculate intangible assets and all data are based on Annual Business Report.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.5
• /
• pp.604-610
• /
• 2018

Recently, due to the rapid growth of the leisure industry, demand for small-scale flotation and mooring pontoon platforms has been increasing rapidly. Standard rules for the design and structural safety of such structures have become necessary. This paper provides criteria that can be referenced when designing pontoon platforms, and also introduces structural safety evaluation procedures. In this study, the structural safety and stability of a 15-meter pontoon platform were investigated through structural design and finite element analysis. For platforms of less than 10 meters in length, a simple structural calculation can be used, but for platforms over 10 meters, a detailed structural strength review must be considered to meet safety guidelines defined in existing regulations. The structural strength of the initial design was examined and its structural safety was verified. For future research, it is an evaluative system was developed that can be used to examine the various loading conditions during design.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.56 no.5
• /
• pp.1-9
• /
• 2014

The DIROM (Daily Irrigation Reservoir Operation Model) was modified to estimate amounts of water release from reservoirs, considering customary irrigation water management practices, such as water supply for puddling and transplanting paddy rice from seeding beds and mid-season drainage. The applicability of the modified model was investigated by simulating amounts of water release from three study reservoirs: Hwamae, Ogi, and Doya Reservoirs. In terms of annual amounts of water release, the relative errors between the observed and simulated values in 2012 and 2013 ranged -26.20 % to 10.28 % and 4.90 % to 30.06 %, respectively; in case of reservoir water levels, the RMSE values ranged 0.45 m to 1.34 m and 0.40 m to 1.27 m, respectively. Also, it was revealed that the model provided better simulation results for monthly water releases than the original model. In addition, the model presented better performance in simulating 10-day amounts of water release from April to June. However, the model had still significant errors in the simulation results from July to September because the reservoirs were practically operated to adapt to water management circumstances. Finally, it is concluded that the modified DIROM can estimate the amounts of water release from reservoirs, reflecting irrigation water management customs in paddy-field districts. To achieve higher prediction accuracy of the model, it is necessary to incorporate practical reservoir operation rules into the model.

• Journal of Korea Technology Innovation Society
• /
• v.14 no.3
• /
• pp.578-598
• /
• 2011

This study estimates the value of photovoltaic core material technology, which is getting attention as a clean energy source. The estimation is based on the real option pricing model (ROPM). This study has two main contributions. The first is in the methodology. The process of modeling volatility, which is the most complicated stage in ROPM, is greatly simplified by using the stock price as a covariate representing the volatility of the real option's basic asset. The second contribution is the application of technology. In this study, the economic value of poly-silicon, a core material in the photovoltaic industry and recently surging in demand, is evaluated as a manufacturing technology. In a case study of a company in the photovoltaic industry, the stochastic process of a basic asset follows geometric Brownian motion (GBM), and the option value of firm A's poly-silicon manufacturing technology is estimated at 3.4 trillion won.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.6
• /
• pp.30-40
• /
• 2014

The demand of underground structure such as box culvert for electric power transmission is increasing more and more, and the service life extension of these structures is very important. Recent observations in field and experimental evidences show that even steel in concrete can be corroded by carbonation reaction of cover concrete. Carbonation-induced corrosion in concrete may often occur in a high carbon dioxide environment. In this study, the risk of carbonation of box culverts in our nation was evaluated by measuring the carbonation rate and concrete cover depth in field. Then, the service life due to carbonation at the cover depth was calculated by in situ information and the Monte Carlo simulation in a probabilistic way. Additionally, the accelerated carbonation test for the cracked beam specimen was executed and the crack effect owing to the carbonation process on the service life of box culvert was numerically investigated via Monte Carlo simulation based on the experimental results.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.4
• /
• pp.969-977
• /
• 2016

Climate change affects the growth of crops which were planted especially in fields, and it becomes more important to use climate data to predict the yields of the major vagetables. The variation of the crop products caused by climate change is one of the significant factors for the discrepancy of the demand and supply, and leads to the price instability. In this paper, using a panel regression model, we predicted the garlic yields with the weather conditions of different regions. More specifically we used the panel data of the several climate variables for 15 main garlic production areas from 2006 to 2015. Seven variables (average temperature, average maximum temperature, average minimum temperature, average surface temperature, cumulative precipitation, average relative humidity, cumulative duration time of sunshine) for each month were considered, and most significant 7 variables were selected from the total 84 variables by the stepwise regression. The random effects model was chosen by the Hausman test. The average maximum temperature (January), the cumulative precipitation (March, October), the cumulative duration time of sunshine (April, October) were chosen among the variables as the significant climate variables of the model