• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.189-197
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• 2004

The thermal rating of an overhead conductor, which is the maximum allowable current, is generally calculated on the basis of heat balance equation found in IEEE P738 standard. This is given as a function of the weather conditions such as air temperature, wind speed, wind direction, and sun heat. Wind speed among such weather parameters is strongly affected on determining the line rating when it appears very low level. Therefore there may occur inaccuracy since most anemometers used in line rating monitor systems may show low resolutions and stall speed performance. In this paper, we introduce a new methodology for determining the dynamic line rating in overhead transmission lines, without using my anemometer. It was shown that wind speed can be estimated by the temperatures of 2 indirect conductors, and through experimental study, the dynamic line rating obtained by the estimated wind speed was very closely that of weather model.

• International Journal of Highway Engineering
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• v.18 no.5
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• pp.127-134
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• 2016

PURPOSES : Visibility of lanes on the road improves as retro-reflectivity rises. This helps reduce traffic accidents at nighttime or in bad weather. This study aimed to evaluate the effects of improved visibility on reduction of traffic accidents when the color of the lane in the median of the highway was changed from yellow to white. METHODS : In order to evaluate the accident reduction effect of the white left shoulder line, Hauer (1997)'s Comparison-Group method was chosen as an analysis methodology. The JungBu-2 highway, which is equipped with the white left shoulder line and is in trial operation, was chosen as a target for analysis. Data of accidents for 10 months before and after installation was collected and analyzed. In addition to the number of accidents, the types of accidents were classified into nighttime accidents, accidents in bad weather, and median collisions. The accident reduction effect of improved visibility of lanes was analyzed. RESULTS : The analysis' finding showed that installation of the white left shoulder line decreased the number of accidents by 28%. Moreover, improvement in visibility was effective in reducing nighttime accidents by 67.63%, accidents in bad weather by 55.19%, and median collisions by 48.55%. CONCLUSIONS : Based on the analysis' results in this study, it was concluded that white left shoulder line on the freeway contributed to reduce traffic accidents, especially nighttime accidents, accidents in bad weather, and median collisions.

• Journal of Environmental Impact Assessment
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• v.15 no.6
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• pp.373-383
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• 2006

The spatial mapping of risk is very useful data in planning for disaster preparedness. This research presents a methodology for making the landslide life risk map in the Boeun area which had considerable landslide damage following heavy rain in August, 1998. We have developed a three-stage procedure in spatial data analysis not only to estimate the probability of the occurrence of the natural hazardous events but also to evaluate the uncertainty of the estimators of that probability. The three-stage procedure consists of: (i)construction of a hazard prediction map of "future" hazardous events; (ii) validation of prediction results and estimation of the probability of occurrence for each predicted hazard level; and (iii) generation of risk maps with the introduction of human life factors representing assumed or established vulnerability levels by combining the prediction map in the first stage and the estimated probabilities in the second stage with human life data. The significance of the landslide susceptibility map was evaluated by computing a prediction rate curve. It is used that the Bayesian prediction model and the case study results (the landslide susceptibility map and prediction rate curve) can be prepared for prevention of future landslide life risk map. Data from the Bayesian model-based landslide susceptibility map and prediction ratio curves were used together with human rife data to draft future landslide life risk maps. Results reveal that individual pixels had low risks, but the total risk death toll was estimated at 3.14 people. In particular, the dangerous areas involving an estimated 1/100 people were shown to have the highest risk among all research-target areas. Three people were killed in this area when landslides occurred in 1998. Thus, this risk map can deliver factual damage situation prediction to policy decision-makers, and subsequently can be used as useful data in preventing disasters. In particular, drafting of maps on landslide risk in various steps will enable one to forecast the occurrence of disasters.

• Computers and Concrete
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• v.26 no.3
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• pp.203-211
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• 2020

Turkey is located in one of the most seismically active regions of in Europe. The majority of the population living in big cities are at high seismic risk due to insufficient structural resistance of the existing buildings. Such a seismic risk brings the need for a comprehensive seismic evaluation based on the risk analysis in Turkey. Determining the seismic resistance level of existing building stock against the earthquakes is the first step to reduce the damages in a possible earthquake. Recently in January 2020, the Elazig earthquake brought the importance of the issue again in the public. However, the excessive amount of building stock, labor, and resource problems made the implementation phase almost impossible and revealed the necessity to carry out alternative studies on this issue. This study aims for a detailed investigation of residential buildings in Antalya, Turkey. The approach proposed here can be considered an improved state of building survey methods previously identified in Turkey's Design Code. Antalya, Turkey's fifth most populous city, with a population over 2.5 Million, was investigated as divided into sub-regions to understand the vulnerability, and a threshold value found for the study area. In this study, 26,610 reinforced concrete buildings between 1 to 7 stories in Antalya were examined by using the rapid visual assessment method. A specific threshold value for the city of Antalya was determined with the second level examination and statistical methods carried out in the determined sub-region. With the micro zonation process, regions below the threshold value are defined as the priority areas that need to be examined in detail. The developed methodology can be easily calibrated for application in other cities and can be used to determine new threshold values for those cities.

• The Journal of Industrial Distribution & Business
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• v.10 no.1
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• pp.69-76
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• 2019

Purpose - The purpose of this paper is to empirically investigate the effectiveness of Offcial Development Assistance (ODA) in recipient countries' economy. ODA is designed to mitigate poverty and stimulate economic growth in the developing countries. We classify total ODA into bilateral ODA and multilateral ODA depending on the number of donor countries. If the ODA flows from one donor country to one recipient country, it is classified as bilateral ODA. If the multiple countries simultaneously become donor countries through the international organizations such as United Nations and World Bank, it is classified as multilateral ODA. This paper compares the effect of bilateral ODA and multilateral ODA in determining recipient countries' economic development, and tries to provide policy implications to Korean ODA. Research design, data, and methodology - Our primary explanatory variables are bilateral and multilateral ODA. Private credit in recipient countries is adopted as additional explanatory variables to capture the level of financial development in recipient countries. We measure the ODA effectiveness using economic growth and quality of life of the recipient countries as the dependent variable. We collect 142 recipient countries' data from OECD statistics, during the period from 1970-2014. Panel least squares estimation with country fixed effect is employed as the empirical model. Results - Our results support that ODA variable has a negatively significant impact on recipient countries' economic growth, while it is positively correlated with human development index. Recipient countries' private credit is positively correlated with economic growth and human development index. The interaction variable of ODA and financial development turns out to be significant in general. We find that the positive effect of ODA depends on recipient countries' financial market development and this effect is stronger in multilateral aid than bilateral one. Conclusions - From the analysis, we have confirmed that the recipient countries financial development is the necessity condition to achieve positive effect of ODA. Based on these results, we suggest that Korean government should increase the share of multilateral funding and pay attention to recipient countries' financial market development to maximize the effectiveness of ODA.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.2
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• pp.245-256
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• 2016

Prediction of TBM performance is very important for machine selection, and for reliable estimation of construction cost and period. The purpose of this research is to analyze the evaluation process of various prediction models for TBM performance and applied methodology. Based on the solid literature review since 2000, a classification system of TBM performance prediction model is proposed in this study. Classification system suggested in this study can be divided into two stages: selection of input parameter and application of prediction techniques. We also analyzed input and output parameters for prediction model and frequency of use. Lastly, the future research and development trend of TBM performance prediction is suggested.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.223-230
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• 2011

According to EMEP/EEA Emission Inventory Guidebook, the emissions produced by vehicle in cold start phase should be calculated differently compared to hot start phase. In this study, considering this driving cycle, more appropriate procedures for estimating Environmental Benefits was suggested. Using Tier 3 standard, all links within the impact area were included in estimating emissions. Traffic volume and travel distance were analyzed using EMME/3 software. For application of the procedures in this study, the case study was carried out with real transportation project. As a result, the Environment-Benefits increased by 30%. If the methodology suggested in this study is applied to feasibility study it will help to activate the investment of the environment-friendly modes like railway in the future.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.924-934
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• 2014

In the last 10 years the digital music contents market has grown rapidly. However digital music contents product and services are not managed with product planning and price policy considered customer attitude and digital music contents values. This study is to define the value properties of digital music contents services based on streaming and download as genre, price, sound quality, and usage appliance, and suggest the strategic market price and service composition of digital music contents service by customer attitudes about the value properties. The research used the conjoint analysis methodology based on the hedonic price model and collected 405 questionaries by users of Korean digital music contents services to the analysis. Hence 'sound quality' in download platform, and 'appliance' in streaming platform were the elements to evaluate the customer attitude. The results present the music contents productions and companies have to provide the differentiated services and price by the value properties of user preference in the market.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.400-403
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• 2015

BACKGROUND/OBJECTIVES: By the year 2050, thirty-eight percent of the Korean population will be over the age of 65. Health care costs for Koreans over age 65 reached 15.4 trillion Korean won in 2011, accounting for a third of the total health care costs for the population. Chronic degenerative diseases, including coronary heart disease (CHD), drive long-term health care costs at an alarming annual rate. In the elderly population, loss of independence is one of the main reasons for this increase in health care costs. Korean heath policies place a high priority on the prevention of CHD because it is a major cause of morbidity and mortality. SUBJECTS/METHODS: This evidence-based study aims to the estimate potential health care cost savings resulting from the daily intake of omega-3 fatty acid supplementation. Potential cost savings associated with a reduced risk of CHD and the medical costs potentially avoided through risk reduction, including hospitalizations and physician services, were estimated using a Congressional Budget Office cost accounting methodology. RESULTS: The estimate of the seven-year (2005-2011) net savings in medical costs resulting from a reduction in the incidence of CHD among the elderly population through the daily use of omega-3 fatty acids was approximately 210 billion Korean won. Approximately 92,997 hospitalizations due to CHD could be avoided over the seven years. CONCLUSIONS: Our findings suggest that omega-3 supplementation in older individuals may yield substantial cost-savings by reducing the risk of CHD. It should be noted that additional health and cost benefits need to be revisited and re-evaluated as more is known about possible data sources or as new data become available.

• Journal of Distribution Science
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• v.16 no.4
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• pp.83-88
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• 2018

Purpose - This study conducts an empirical analysis on gasoline pricing of Korean retail gas stations focusing on spatial effects. Unlike previous studies, the study uses an official land price for a proxy of the importance of location, and also allows the spatial effects from other competing gas stations as well. Research design, data, and methodology - In collection of data, we obtain more abundant data than those of previous studies. The gasoline prices used in the study are 909,084 observations as daily data from January 1 to July 31 of the year 2016. A proxy for the land price is collected by linking official public land price data with address information on each gas station. For the estimation, the study employs the Panel Spatial Dubin Model to make the best use of the collected location information. Results - As expected, spatial properties of gas stations have significant effects on the gasoline price. As the price per square meter increases by 100 thousands won, the price of gasoline rises 9 won per liter. Among other characteristics, the price increases by 16 won per liter if the station has a convenience store, and about 5 won if it has a car wash service. Gasoline price in Singapore accounted for 26% of variations in domestic gasoline prices. SK Energy and GS Caltex are the top brands in terms of price. The study also finds prices and other important properties of competing gas stations have significant effects on others' prices. Prices of competing gas station have a positive relationship with those of others. If a competing gas station raises the price, the gas station also raises the price, and lowering the price lower the price. Among brands, GS Caltex has the greatest downward pressure on nearby gas stations. Conclusions - The study confirms that location value of gas stations affect their gasoline prices, and the prices of the competing gas stations also have a significant effects on their prices. It suggests that the prices in the competing retail areas tend to be synchronized with each other.