• Journal of Korea Water Resources Association
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• v.42 no.6
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• pp.457-464
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• 2009

This paper proposes methodologies for analyzing the accuracy of the proportional hazards model in predicting consecutive break times of water mains and estimating the time interval for economical water main replacement. By using the survival functions that are based on the proportional hazards models a criterion for the prediction of the consecutive pipe breaks is determined so that the prediction errors are minimized. The criterion to predict pipe break times are determined as the survival probability of 0.70 and only the models for the third through the seventh break are analyzed to be reliable for predicting break times for the case study pipes. Subsequently, the criterion and the estimated lower and upper bound survival functions of consecutive breaks are used in predicting the lower and upper bounds of the 95% confidence interval of future break times of an example water main. Two General Pipe Break Prediction Models(GPBMs) are estimated for an example pipe using the two series of recorded and predicted lower and upper bound break times. The threshold break rate is coupled with the two GPBMs and solved for time to obtain the economical replacement time interval.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.6
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• pp.599-612
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• 2013

This study aims to investigate an economical efficiency of two excavation methods with respect to the room-and-pillar method for the underground space and conventional excavation method, i.e. 2-arch tunnelling method. For feasibility study, an excavation cost for both room-and-pillar method and 2-arch tunnelling method was estimated when the same space in operation was required. It was assumed that properties of reinforcements and rock were adopted from literatures. However, an excavation shape of the room-and-pillar method was assumed not to be the rectangular shape which is a general type in the room-and-pillar method but to be an arch shape in order to compare with the conventional excavation method (2-arch tunnelling) and to achieve the maximum bearing capacity of the structure during excavation. Consequently, the wider space in use or required and the better condition of rock we assumed, the more economical advantage we have in the room-and-pillar method than the 2-arch tunnelling method.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.1
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• pp.12-20
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• 2013

This aim of this study is to support the value criteria that citizen evaluate themselves it when they found modern heritages in their town. To understand the changing of value criteria for the cultural heritage, we have to begin from early 20 century that were, however, diversified after 80's. As a result, early they evaluated with the architectural and aesthetic value mainly, after they evaluated with the social-cultural value and academical value, and nowadays they try to include the economical value and educational value. So this study rearranged and divided that value with the preservation and using value. The preservation value include the historical value, aesthetic value, social-cultural value and academical value, and the using value include the economical value and educational value. The criteria, however, don't have the equal importance, This study try to redefine relative importance score with paired comparison. As a result, Historical value is proved that most important criteria, but aesthetic value got the score lower than social-cultural value, and similar with academical values. And in using values, economical value and educational value got the low score. It means that if some researcher insist about the importance of economical value, it should evaluate lower than preservation values. This study insist that we have to include diversified values and that values have relatives score. Actually, now we mostly evaluate with the architecture and aesthetic values about modern heritage, so we are losing a lot of modern heritage. If we include the diversified values, social-cultural, academical and educational value, we can conserve our important modern heritage and revitalizing town with tourism of historical heritage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.809-819
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• 2004

In this paper, in order to exclude the expansion of M/W relay frequency or its new frequency assignment possibly, we analyzed a possibility of substituting M/W system by B-WLL or optical fiber network regarding service quality and economical points. To define the target of service quality, pre-condition and analysis method for the selected media have been derived to compare each other. E1 transmission with BER 10$^{-1}$ was chosen as a reference capacity, and service distance was calculated f3r the selected media as a function of availability. Also from the economical point we considered 3 systems such as optical fiber, M/W, and B-WLL based upon basic system structure, and analyzed them for various line configurations of fiber optic and B-WLL according to service period, system capacity, transmission distance, and data rate. It was confirmed that B-WLL can provide quality of service with 99.999 % availability within 1.6 km cell radius, and for optical fiber substitution, the leased fiber conduit on an electric pole is more economical than M/W system irrespective of service period, but in case of directly digging for underground conduit, it turned out ineffective regardless of cabling duct types.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.286-299
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• 1998

This study was conducted to do a comparative analysis of hunting system in 16 OECD(Organization for Economic Co-operation and Development) countries. Hunting is one of the most advanced types for developing natural resources, esp. wildlife, which is one of major products from forest. There are two types of hunting system ; Revier and/or License System, around most countries which have traditional advanced hunting and higher hunter population. Licence system, which is chosen in Korea, is less efficient ways of hunting for maximizing economical value and wildlife management than Revier system does. Adopting better system for much more efficient economical condition from hunting in Korea in a future is a ultimate goal in this study. The first step for the goal is an analysis of these two system among 16 OECD countries ; United State, Japan, Germany, France, etc. Comparative researches in hunting regulations such as number of hunters, hunter ratio to population, hunting bags, game species, seasons, ammunition and hunting permit are a next step for adopting developed hunting system in Korea. Korea has a smallest hunter ratio to population (1/2,463) among 16 OECD centuries and economical value lead by hunting is estimated still very low. Revier system is a popular one in most OECD countries except United State, Japan, etc, which is useful for wildlife management and maximizing economical value of hunting. And usually rifles are permitted for big game hunting. Hunting examination and/or insurance are compulsory for achieving hunting permit. Depend on game species, yearly hunting bag and season are constructed in most OECD countries.

• Journal of the Korea Institute of Building Construction
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• v.9 no.6
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• pp.161-168
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• 2009

In an architectural construction, underground construction is a critical path forming a major part of the total construction period and cost, and particularly in big cities, its size has been increasing every year. A basement wall currently constructed in the field needs a large functional work force, and the construction is under progress by the Euroform and Soldier system, which is disadvantageous in terms of the construction period. Therefore, in this research, non-supporting forms which are applicable to the buildings construction were developed, based on the non-supporting forms partly used in some civil engineering works. In addition, the size of a form was assumed and its economical efficiency was compared to that of the Euroform and Soldier system which is used most in construction fields, and the results were analyzed. The study results showed that the construction cost of composite non-supporting forms was higher than that of the Euroform and Soldier system by about 8%, and the construction cost of non-composite non-supporting forms were lower than that of the Euroform and Soldier system by about 9%. However, in the case of composite non-supporting forms, the amount of concrete and reinforcing rods remarkably decreased in structural construction, so it has the effect of an economical cost reduction compared to the construction cost of existing walls by about 35%

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.296-312
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• 2011

Korea has been suffering from financial hardship with low birth rate and rapid growing of advanced aged people because low economic growth and low interest rate have continued after IMF foreign-exchange crisis. Under these circumstances, it is necessary for the middle-aged people to have well-prepared retirement plan in the sense of physical, psychological, social and economical preparedness. The study intends to find out how the occupation and activity characteristics affect the physical, psychological, social and economical preparation for their remaining old age. For the purpose, questionnaires were collected from 344 middle-aged people working in private companies, public offices and small-business owners in metropolitan and Chungcheong province. The findings are as follows: First, they were physically well-prepared, as they thought their leisure activity was more important, their occupational role was more stable and they were old and healthy. Second, Women had notion about their occupation if they kept a good relationship with their colleagues. And they were psychologically prepared well as they valued their leisure activities. Third, if they perceived their occupations as stable and had more social and leisure activities, they were socially well-prepared. Fourth, Although the level of economical preparation depends on their wealth, the occupation and activity characteristics had no effect on the economical preparation. These findings imply that the retirement preparation as a recent social issue has been influenced by the nature of occupation and activity and suggest that the definite policy and program will be required for the retirement preparation of the middle-aged people from various aspects.

• Journal of Agricultural Extension & Community Development
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• v.3 no.2
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• pp.197-209
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• 1996

Bangladesh that is known as the poorest country of the world has the large land of fertile soil and very good environment to live, even though we think she may be very bad to live. People being habituated to that good environment, the population explosion made the people to be starven, but the treatment has been simple support without deep analysis of the root of poverty. As the result it is general that the poverty is severer and severer in spite of continuous support. For the last century Korea changed from the country of poverty and despair to that of development and hope, to be model mid vision of under development countries including Bangladesh. At this point it is necessary to look back the way of development to help them to solve their poverty problem. That is the goal of this project, and this thesis is the result of it. It is evaluated for the 1st 5 years work of the project to apply the result to the next 5 years plan. This project had been proceeded from 1. Jul. 1990 to 30. Jun. 1995 at Chilmari area of Bangladesh, with teaching and training to wake up the mentality of the people, demonstration farming and cooperative association. It was proceeded as the Agriculture project of KDAB(Korean Development Association in Bangladesh, an NGO registered to Bangladesh) supported by Good Neighbors, KOICA and many churches and individuals. Especially the teaching and training work was proceeded as the branch of the Canaan Farmer`s School of Korea with instruction and support. After the basic survey for project, the confirmation of working place and the preparation of training facility, 10 times of long term training(3 months worse, boarding) was completed, with many times of short term training, informal training, demonstration farm, various demonstrating works. The results of the work are understanding of the not of problem by participatory observation, making plan to solve it, getting the trust from the people and beginning the practical work with the trainees for development of economy and living situation. The biggest problem of Bangladesh is being understood losing the desire to solve the poverty problem and the self-confidence to be able to do it. It is the conclusion that after solving the problem of thought and mentality, the education, technology and money can be effective for development. So the 1st 5 year project is evaluated as the basic work to analyse the root of problem, to chance mentality of people and to search income source. The next goal is to promote practical living level of people. For that it is necessary to develope die mentality of people including responsibility and self-confidence by teaching and training, to educate cooperative association and technology for economical development, to proceed integrated rural development work with economical development, educational improvement and reformation of environment. It is very important result that they decided to grow poultry for main economical source of Chilmari area, to do economical development work by joint operation of poultry through cooperative association.

• Korean Journal of Culture and Social Issue
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• v.13 no.2
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• pp.1-15
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• 2007

The purpose of this study is to find how the factors of "Grief of loss" affect on the subjective well-being of elderly('the satisfaction with life', 'the positive affect', 'the negative affect). One hundred of subjects, over age 65, participated in the survey and we could find that the "Grief of loss" was composed of four sub-factors('economical loss', 'loss from being parted by death', 'loss of physical functions', 'loss of relations'). These four sub-factors of "Grief of loss" showed negative correlations with the scores of the satisfaction with life. However, three other sub-factors except 'loss from being parted by death' showed negative correlations with the scores of 'the positive affect'. On the other hand, other three sub-factors except 'economical loss' showed positive correlations with the scores of 'the negative affect'. Especially, the 'economical loss' was affecting on 'the negative affect' and 'the positive affect' significantly. Also, 'loss of relations' was affecting on both 'the negative affect' and 'the satisfaction with life''. Two out of the four sub-factors, 'economical loss' and 'loss from being parted by death', showed no significant effects on the subjective well-being. This results insists us that the emotional supports, especially from their offspring, are truly important for elderly to overcome their Grief of loss('loss of physical functions', 'loss of relations')

• Polymer Science and Technology
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• v.18 no.5
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• pp.465-474
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• 2007