• Journal of Korean Society of Transportation
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• v.19 no.3
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• pp.7-18
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• 2001

The pedestrian signal systems operating presently could provide more time for the pedestrian to cross the street than the previous system, but it would increase the cycle length and cause longer delays at the signalized intersections. For instance, more than 80% of traffic signals would have to have the cycle length increased by 10sec in Daegu Metropolitan areas. Therefore. the purpose of this study is to propose a pedestrian traffic signal time that not only maintains the safety of the pedestrian but also reduces the traffic cycle length. The proposed pedestrian signal time is set to enable enough time for the elderly to cross and the flashing time is set low enough to deter the ordinary person. This new pedestrian signal time can reduce the traffic cycle length at intersections and prevent the Pedestrian crossing during flashing time. In addition to the flashing green should be changed to flashing red to warn the pedestrian he should not begin crossing as opposed to the flashing green which suggest he could cross. In this study, the speed of 1.1m/sec and 0.85m/sec are applied to the new proposed signal time for normal and elderly person respectively after analyzing data collected at Daegu Metropolitan area.

• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.35-47
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• 2008

The low flow analysis is an important part in water resources engineering. Also, the results of low flow frequency analysis can be used for design of reservoir storage, water supply planning and design, waste-load allocation, and maintenance of quantity and quality of water for irrigation and wild life conservation. Especially, for identification of the uncertainty in frequency analysis, the Bayesian approach is applied and compared with conventional methodologies in at-site low flow frequency analysis. In the first manuscript, the theoretical background for the Bayesian MCMC (Bayesian Markov Chain Monte Carlo) method and Metropolis-Hasting algorithm are studied. Two types of the prior distribution, a non-data- based and a data-based prior distributions are developed and compared to perform the Bayesian MCMC method. It can be suggested that the results of a data-based prior distribution is more effective than those of a non-data-based prior distribution. The acceptance rate of the algorithm is computed to assess the effectiveness of the developed algorithm. In the second manuscript, the Bayesian MCMC method using a data-based prior distribution and MLE(Maximum Likelihood Estimation) using a quadratic approximation are performed for the at-site low flow frequency analysis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.407-414
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• 2010

The fairway within the area of Yul-do and Songdo located near the Myeongnyang-sudo approaches south of Mokpo harbor is well guided by traffic separation scheme and other navigational aids. However, that part of the waterways where Yul-do is located sits at the cross-roads of marine traffic and is subjected to some potential risks in the voyage navigation: the effect of climatic phenomenon, the disregard of most ships in using the western sector of the fairway creating a congestion in the eastern sector, and lastly, the disadvantageous erect of the location and height of Yul-do island that hinders good lookout. This study investigates the environmental conditions that prevailed in the area in the span of 5-year period and the marine traffic situation taken from the data within the 72-hour period The navigational hazards and marine casualties are also be presented. The results are analyzed and are made the basis of a proposal for an improved separation of traffic. Thereafter, an evaluation is carried out by using the components of marine traffic flow simulation and ES modeling index. It is evaluated through simulation by the use of full-mission ship handling simulator.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.85-90
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• 2005

Inundation of Transformer Vault breaks out every summer season in low-tying downtown and low-tying shore by localized heavy rain, typhoon and tidal wave. In case inundation of Transformer Vault, it occurs a great economic loss owing to recovery time and events of electric shock occur by inundation electrical facility. So we need installation plan of Transformer Vault in common flood area for preventing from economic loss and equipment events. Therefore we research distribution of 22.9[kV] Transformer Vault in common flood of the country and analyze field condition about flood protection plan. And we analyze regulation or law relating to the flood protection counterplan of US, England, Australia. This paper will be used to present a reform proposal of electrical related law about flood protection of existing Transformer Vault. Also we present considering facts at the time Transformer Vault installation in common flood area.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.163-198
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• 2000

This study aim was to propose plant taxa as an alternative proposal for the purpose of solving many kinds of difficulties occurred in the floral item of environmental impact assessment (EIA) used to date. Plant taxa presented here for environmental assessment can probably be useful in understanding the excellence of natural environment to specific regional space as well as in determining the order of priority as to species preservation. These taxa, selected by the floristic analysis with distributional range, can be classified into five degrees: the fifth degree, characterized by the discontinuous and/or isolated distribution, includes 83 taxa, 76 genera, 41 families; the fourth degree, occurred in only one subprovince as southern and northern plants, includes 314 taxa, 217 genera, 78 families; the third degree, two subprovinces as southern and northern plants, includes 307 taxa, 223 genera, 93 families; the second degree, generally distributed more than 1,000 meter in altitude, a whole subprovince, includes 109 taxa, 92 genera, 43 families; the first degree, at least three subprovinces, includes 258 taxa, 207 genera, 91 families. The taxa mentioned here environmental assessment, therefore, summed up to 1,071 taxa, 559 genera, 142 families from the Korean flora. It is suggested that the taxa belonging to the fifth degree might structually have by far extinctive possibility in respond to environmental damage comparing with other degrees, simply because these have narrow distributional ranges. [Floristics, Korean flora, Geographical distribution, Natural environment, Environmental assessment, Plant taxa].

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.3
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• pp.1-8
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• 2008

The purpose of this study is to understand the conflicts that occurred in the rural village's joint management project. This study examined the perception of conflicts among people working in agricultural related fields. A questionnaire survey was given to collected data from people who participated in nation-wide resrvice training course programs. The content of the questionnaire consisted of the factors of conflict in a rural village and the details recognized by general farmers. The data was collected from October 15 to 23, 2007. 206 samples were used for final analysis from a total of 240 samples. Frequency analysis and T-test between variables were conducted by SPSS 14.0. The results suggest that farmers have a negative perception of the business partnership. Proposal for business partnerships should be avoided because of the conflicts between partners. Accordingly, as farmers don't recognize that their joint project is a business partnership, the likehood of a conflict in the agricultural joint business operation and management is contained. Conflicts mainly exist between a village leader and villagers. The main reasons for conflicts are a lack of interest and lack of communal homogeneity, and lack of methodology to share the benefit of business. It will be necessary to understand the aspects of future conflicts in order to manage joint projects ill agricultural experience villages.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.299-309
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• 2006

Due to the rapid development in mobile communication technologies, the usage of mobile devices such as cell phone or PDA becomes increasingly popular. As different devices require different applications, various new services are being developed to satisfy the needs. One of the popular services under heavy demand is the Location-based Service (LBS) that exploits the spatial information of moving objects per temporal changes. In order to support LBS efficiently, it is necessary to be able to index and query well a large amount of spatio-temporal information of moving objects. Therefore, in this paper, we investigate how such location information of moving objects can be efficiently stored and indexed. In particular, we propose a novel location encoding method based on hierarchical administrative district information. Our proposal is different from conventional approaches where moving objects are often expressed as geometric points in two dimensional space, (x,y). Instead, in ours, moving objects are encoded as one dimensional points by both administrative district as well as road information. Our method is especially useful for monitoring traffic situation or tracing location of moving objects through approximate spatial queries.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.9
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• pp.667-674
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• 2014

A ship's propulsion shafting system is subjected to varying magnitudes of intermittent loadings that pose great risks such as failure. Consequently, the dynamic characteristic of a propulsion shafting system must be designed to withstand the resonance that occurs during operation. This resonance results from hydrodynamic interaction between the propeller and fluid. For ice-class vessels, this interaction takes place between the propeller and ice. Producing load- and resonance-induced stresses, the propeller-ice interaction is the primary source of excitation, making it a major focus in the design requirements of propulsion shafting systems. This paper examines the transient torsional vibration response of the propulsion shafting system of an ice-class research vessel. The propulsion train is composed of an electric motor, flexible coupling, spherical gears, and a propeller configuration. In this paper, the theoretical analysis of transient torsional vibration and propeller-ice interaction loading is first discussed, followed by an explanation of the actual transient torsional vibration measurements. Measurement data for the analysis were compared with an applied estimation factor for the propulsion shafting design torque limit, and they were evaluated using an existing international standard. Addressing the transient torsional vibration of a propulsion shafting system with an electric motor, this paper also illustrates the influence of flexible coupling stiffness design on resulting resonance. Lastly, the paper concludes with a proposal to further study the existence of negative torque on a gear train and its overall effect on propulsion shafting systems.

• Journal of Society of Preventive Korean Medicine
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• v.3 no.2
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• pp.55-77
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• 1999

Oriental Medical Service established foundation that Oriental medical clinic can take part in industrial health service by being specified industrial calamity medical treatment organ, but research which develope program that Oriental Medical Service approach on the occupational disease and industrial health only dealt in the Western Medical System was insufficient. So we studied on theoretical foundation and basic bearing about .program of oriental medical health examination in the workplace, it is based on explanation and assessment reformed by western medicine. We reached the conclusion as follows, 1. We must reconsider the concept that mind of Oriental medicine is preventive medicine, and assess positively result of social medicine. 2. Importance of industrial health is being enlarged in the category of health care. 3. Western medical health in including industrial health have faced much problems at this time, we can search by alternative proposal grafting on Oriental Medicine. 4. Oriental medical participation in the industrial health have various benefits at side satisfaction of workers, effect of prevention, efficiency of cost, and increasing rate of medical treatment and return to workplace of workers with industrial calamity. 5. We must consider Oriental Medical Health Examination as one way of health management program of workers, not as formality. 6. The advantage of Oriental Medical Health Examination can increase ability of individual health management in preventive medicine and the production in workers' health management.

• Journal of Korean Society of Transportation
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• v.34 no.5
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• pp.421-436
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• 2016

Public-Private-Partnerships tend to be committed high project development cost and recover the cost through future revenue during the operation period. In general, long-term concession can bring on more revenue to private investors, but short-term concession less revenue due to the short recovering opportunities. The concession period is usually determined by government in advance or by the private sectors's proposal although it is a very crucial factor for the PPPs. Accurate traffic forecasting should be most important in planing and evaluating the operation period in that the forecasted traffic determines the project revenue with user fees in PPPs. In this regards, governments and the private investors are required to consider the traffic forecast risk when determining concession period. This study proposed a model for the optimal concession period in the PPPs transportation projects. Monte Carlo simulation was performed to find out the optimal concession period while traffic forecast uncertainty is considered as a project risk under the expected return of the private sector. The simulation results showed that the optimal concession periods are 17 years and 21 years at 5.5% and 7% discount level, respectively. This study result can be applied for the private investors and/or any other concerned decision makers for PPPs projects to set up a more resonable concession period.