• Ocean Systems Engineering
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• 제9권3호
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• pp.261-285
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• 2019

Nowadays in offshore industry there are emerging hazards with vague property such as act of terrorism, act of war, unforeseen natural disasters such as tsunami, etc. Therefore industry professionals such as offshore energy insurers, safety engineers and risk managers in order to determine the failure rates and frequencies for the potential hazards where there is no data available, they need to use an appropriate method to overcome this difficulty. Furthermore in conventional risk based analysis models such as when using a fault tree analysis, hazards with vague properties are normally waived and ignored. In other word in previous situations only a traditional probability based fault tree analysis could be implemented. To overcome this shortcoming fuzzy set theory is applied to fault tree analysis to combine the known and unknown data in which the pre-combined result will be determined under a fuzzy environment. This has been fulfilled by integration of a generic bow-tie based risk analysis model into the risk assessment phase of the Risk Management (RM) cycles as a backbone of the phase. For this reason Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) are used to analyse one of the significant risk factors associated in offshore terminals. This process will eventually help the insurers and risk managers in marine and offshore industries to investigate the potential hazards more in detail if there is vagueness. For this purpose a case study of offshore terminal while coinciding with the nature of the Caspian Sea was decided to be examined.

• 한국환경과학회지
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• 제25권1호
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• pp.99-105
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• 2016

In this paper, a groundwater hydrological study of the Gyeongju well during the Silla period is conducted to investigate how sufficiently the Gyeongju well supplied water demand at the time. It is assumed that the current geology and soil condition in Gyeongju remain similar to the Silla period. Also, the land use and land coverage during the Silla period is estimated based on the current land condition in Gyeongju. Precipitation during the Silla period is analyzed using precipitation data from 1984 to 2014 provided by Gyeonju weather station. Precipitation analysis is applied based on 3 different scenarios; precipitation intensity during the Silla period was Case (1) the same as, Case (2) 30% more, and Case (3) 30% less than the precipitation intensity of the last decade (2005~2014). Furthermore, to observe the use of the well in Gyeongju during droughts, the following condition(Case (4)) is also considered; ten year drought during the Silla period was the same as the ten year drought from 1984 to 2014. Available amount of groundwater development is analyzed using NRCS-CN method. The results show that the potential amount of groundwater in Gyeongju during Silla era was for Case (1) $62,825,272m^3/year$, Case (2) $93,606,567m^3/year$, Case (3) $32,277,298m^3/year$, and Case (4)$32,870,896m^3/year$. Also, it has been shown that $45,260,000m^3$ of groundwater were required to supply to all households in Gyeongju during Silla era. Therefore, if the precipitation intensity during Silla era was similar with the last decade, the groundwater would provide enough supply to all households in Gyeongju. However, in the case that the precipitation intensity during Silla era was 30% less than the last decade or a ten year drought happened, it is predicted that the water use in Gyeongju would have been limited.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.52-63
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• 2008

The side collision reconstruction algorithm is developed using three dimensional car crash analysis. Medium size passenger car is modeled for finite element analysis. Total 24 side collision configurations, four different speed and six different angle, are set up for making side collision database. Deformation index and degree index are built up for each collision case. Deformation index is a kind of deformation estimate averaging displacement of side door of crashed car from finite element analysis result. Angle index is constructed measuring deformed angle of crashing car. There are two kinds of angle index, one is measured at driver's side and the other is measured at passenger's side. Also a collision analysis information in side of cars is used for giving a basis for scientific and practical reason in a reconstruction of the car accident. The analysis program, LS-DYNA3D is utilized for finite element analysis program for a collision analysis. Those database are used for side collision reconstruction. Side collision reconstruction algorithm is developed, and applied to find the collision conditions before the accident occurs. Three example collision cases are tried to check the effectiveness of the algorithm. Deformation index and angle index is extracted for the case from the analysis result. Deformation index is compared to the established database, and estimated collision speed and angle are introduced by interpolation function. Angle index is used to select a specific collision condition from the several available conditions. The collision condition found by reconstruction algorithm shows good match with original condition within 10% error for speed and angle. As a result, the calculation from the reconstruction of the situation is reproducing the situation well. The performance in this study can be used in many ways for practical field using deformation index and degree index. Other different collision situations may be set up for extending the scope of this study in the future.

• 한국환경과학회지
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• 제16권5호
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• pp.561-569
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• 2007

This study used SCS-CN method to estimate the real recharge of the study area which is one of the most reasonable techniques to estimate groundwater recharge when there is no available runoff data in a watershed. From the results of tile real recharge analysis for the study area using SCS-CN method, it was analyzed that the year 1994 when the drought was severe shotted the lowest recharge of 106.3mm with recharge rate of 12.4%, and the highest recharge of 285.6mm with recharge rate of 21.8% occurred in 1990. Yearly average recharge of 213.2mm was obtained, and tile average recharge rate was 16.9%/year. KOG-FLOW model which has powerful post process functions consists of setting environments for input parameters in Korean language, and help function is added to each input data. Detailed information for each parameter is displayed when the icon is placed on the input parameters, and geologic boundaries or initial head data for each layer can be set easily on work sheet. The relative errors (R. E.) for each model's observed values and calculated values are $0.156{\sim}0.432$ in case of KOG-FLOW, and $0.451{\sim}1.175$ in case of WINFLOW, therefore it is known that KOG-FLOW model developed in this study produced results compared to observed head values.

• 수면정신생리
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• 제5권2호
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• pp.210-215
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• 1998

OSA(Obstructive Sleep Apnea) is a condition with repeated obstruction of the upper airway while sleeping. This obstruction of the upper airway may result if sleep-induced physiologic change in muscle activity is superimposed on various structural defects of the upper airway. Macroglossia, micrognathia, retrognathia, and decreased airway lumen have all been implicated in OSA. There are a variety of surgical and nonsurgical treatment modalities currently available for OSA. Recently the uvulopalatopharyngoplasty has achieved widespread use, but success rates vary and long-term effects are still unknown. Current nonsurgical treatment methods can be cumbersome and uncomfortable with variable responses. For this case. we diagnosed as OSA by using polysomnographic analysis and cephalometric analysis, and delivered intraoral removable appliance which is more conservative, reversible and easy to use for patient. And we got results that Apnea Index(AI) decreased from 14.4 to 3.1, Total Respiratory Disturbance Index(Total RDI) decreased from 18.1 to 7.0 and removal of chronic headache in daytime.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.285-287
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• 2005

During fabrication of deck house block in passenger ships, the problem of unexpected large deformation and distortion frequently occurs. In this case, line and spot heating method were widely used to correct the distortion of thin plate structure. Spot heating was especially used for the case under 5mm thickness. Few papers are available on the working conditions of spot heating method but only little information on deformation control. In this study, evaluation was carried out on the temperature distribution of spot heating methods using FEA and practical experiments for various heating time. IIn FEA, heat input model was established using Tsuji's double Gaussian heat input mode (Tsuji, I., 1988). This model was verified by comparing with experimental data. Also radial shrinkage and angular distortion due to spot heating were determined and compared with experimental results. Thermo elasto-plastic analysis was performed using commercial FE code, MSC/MARC. Radial shrinkage and angular distortion were measured using 3D measuring apparatus. Based on these results, simplified analysis model for deformation by spot heating was established.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.1032-1037
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• 2003

Although the holes on the shell case are very important fer the acoustic performance, it is difficult to solve the problem because the case includes thin bodies. Hence, in the past, only the method of trial and error, which depends on the engineer's intuition and experience, was available fur the design of holes. Many researchers have tried to solve the thin-body acoustic problems, since the conventional boundary element method (BEM ) using the Helmholtz integral equation fails to yield a reliable solution fer the numerical modelling of radiation anti scattering of sound from thin bodies. In the area of the analysis of thin-body acoustic problem, three approaches are generally used; the multi-domain BEM, the indirect variational BEM, and the normal derivative integral equation And there has been just a f9w study reported on the design optimization for the acoustic radiation problems by using only the conventional BEM. For the thin-body acoustics, however, no further study in the optimization fields has been reported. In this research, the normal derivative integral equation is adopted as an analysis formulation in the thin-body acoustics, and then used fur the optimization. The analytical approaches for the design of holes are proposed by using a topology optimization technique and a genetic algorithm. The proposed approaches are implemented and validated using numerical examples.

• 대한조선학회지
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• 제17권4호
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• pp.1-11
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• 1980

Stiffened plates are commonly used as a component of ship's structures. Most frequently symmetrically stiffened plates are used, but some of stern structures and any specified parts are often constructed with eccentrically stiffened plates. The problems of these eccentrically stiffened plates have been studied rarely, and the results of eccentricity effect of eccentrically stiffened plates are not available. This paper deals with the analysis of eccentrically stiffened plates in the linear elastic range. The derivation of the stiffness matrix was carried out by finite element method for which the isoparametric element was adopted. To show the effect of eccentricity, the deflection at the center under the uniformly distributed and the concentrated load of simply supported and clamped plate models are computed respectively in accordance with the eccentricity of the stiffener. As shown in the results of computations, the eccentricity effect of concentrated load case is greater than that of distributed load case and that of simply supported boundary condition is greater than that of clamped boundary condition. The higher eccentricity of stiffener is, the smaller the effect of stiffener becomes, therefore scantling of eccentrically stiffened plates should be considerably greater than those of symmetrically stiffened plates.

• 한국실내디자인학회논문집
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• 제17권4호
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• pp.42-49
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• 2008

Design concepts of light can be divided into two respects, visual plastic and metaphysical meaning. The current research focuses on the second respect. The meaning of light is abstract characteristics(for example, divinity, spirituality, or image) ultimately expressed by visual plastic. Because it makes architectural space abundant, it have been expressed frequently in architectural space until now. The purpose of this paper is to conceptualize and explain and arrange the meanings of light in the category that have been expressed in architectural space from ancient to current. The method of this study is content analysis and case study, and this is supplement by theoretical consideration on the meaning of light(relationship between perception and meaning, elements to form meaning etc.). This study consists of three steps. Firstly, through the content analysis of existing literature and documents, 17 meanings of light are confirmed. Secondly, these 17 meanings are defined and explained in 3 categories(symbolic, esthetic, and experiential character). Thirdly, they are additionally explained and articulated by case study. In the result, various meanings of light that have been fragmentarily expressed in architectural space until now is clearly arranged at a glance. Those suggested design concepts will be basic conferential material, available to the interior designers and students who want to utilize the organised study concepts.

• 한방비만학회지
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• 제13권2호
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• pp.58-65
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• 2013

Objectives: The objective of this study was to analyse the methods being used to control food intake and physical activity in RCTs of human obesity. Methods: A total of 21 randomized controlled trials (RCTs) were investigated. Nine of which were domestic studies from "http://oasis.kiom.re.kr" and the other of which were foreign studies from systematic reviews of RCTs on herbal medicine for treatment of human obesity. Results: According to domestic studies, "low calorie diet" were recommended in five cases of the domestic studies, "maintain current dietary habit" were recommended in two and no information on diet was two. Considering the seven cases where the information on diet was available, patients' food intake were checked at every visit in six cases. Only two cases among the six had been dropped owing to the violation of dietary habit by patients. Exercises were prohibited in two cases, "maintain current level of phisical activity" were recommended in three cases and, from the rest, no information was available. The level of physical activity were not strictly controlled by any means hence no drop out. According to foreign studies, "low calorie diet" were recommended in two cases, "very low calorie diet (less than 700 kcal/day)" in one case, "maintain current dietary habit" in two cases, "do not eat fat" in two cases and no information was available in the rest five cases. Exercises which concerns spending about 300 kcal/day was recommended in one case, "moderate exercise" were recommended in three cases, "maintain current level of physical activity" were recommended in three cases and no information available in the rest five cases. Conclusions: In order to improve the accuracy of RCT, for the dietary side, researchers should record patient food intake at every visit by means of 24-hour dietary recall methods. This can be supplemented by multiple choice survey that are designed to help patients to diagnose themselves more accurately leading to less bias. For the exercise side, it is highly recommended to confine the exercises to walking only so as to quantify the amount of physical activity more easily by using pedometer.