• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.407-417
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• 2000

To estimate the longitudinal dispersion coefficient at the downstream of Jungrang-River, the undistorted 1/20 scale hydraulic model was used in this study. Experiments were conducted for dry season discharge, and Rhodamine B was used as a tracer. The relationship curve between concentration and conductivity of Rhodamine B was otained by laboratory test, and the conductivity which was measured in hydraulic model was converted to concentration using this curve. The longitudinal dispersion coefficient was calculated using the relationship between the peak concentration and the time to peak concentration. The results of this study were compared with the calculated values by the empirical equations for the longitudinal dispersion coefficient and with the field data. The results of comparison show that Parker's equation underestimates, and Liu'g equation and Iwasa and Aya's one overestimate, and McQuivey and Keefer's equations, Fischer's one, Magazine's one, and Seo and Cheong's one predict relatively well. The measured data sets were relatively close to the observed ones in natural river. The longitudinal dispersion coefficient at the downstream of Jungrang-River was estimated $10\textrm{m}^2/s$.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.268-272
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• 2007

우리나라는 아시아몬순지역에 속하면서 수도작을 주로 하는 지역으로 오래전부터 저수지나 보를 만들어 농업용수를 공급하여 왔으며, 이러한 농업용수의 사용에 대해서는 관행적으로 수리권을 보호해왔다. 그러나 최근 그동안 안정적으로 보호되던 농업용수의 기득 수리권에 대한 재검토와 농업용수의 이용에 따른 사회 경제적 요소의 편익을 기준으로 하는 물 이용의 우선순위 재조정논의가 제기되고 있는데 이는 국가전체 물 수요와 농촌지역사회의 변화 등에 기인한 것이다. 농업용수의 개발과 이용이 기존의 농업생산기반 확충 위주에서 농촌 삶의 질 향상 차원의 농촌 개발로 농업 농촌정책의 방향이 전환되고 있으며, 이와 더불어 농촌의 생활용수, 환경용수, 관광용수, 지역용수 등 농업용수 외의 수자원 수요가 증대하고 있다. 즉 지금까지 농업용수는 주로 농촌의 관개용수 위주로 개발 공급되어 왔으나 농촌지역의 생활양식의 변화 및 생활수준의 향상과 더불어 위생적이고 편리한 생활용수 및 공업용수 등 다양한 목적의 농업(농촌)용수의 수요가 증대 되고 있고 이러한 추세가 지속될 것으로 예상된다. 또한 기계화 영농, 직파 재배 등 영농방식의 변화에 따라 농업용수의 수요가 증가되고 있으며, 농업으로 인한 환경오염을 경감시킬 수 있는 환경친화적인 농업이 요구되고 있어 농촌지역의 한정된 수자원을 합리적으로 이용하여 21세기 물부족 사태에 대비할 필요성이 대두되고 있다. 우리나라에서도 이미 낙동강, 영산강, 섬진강 유역과 남부 해안 및 도서지역의 가뭄이 심각해지는 등 물 부족 문제로 국토 균형개발이 곤란해지는 문제가 발생하고 있다. 이러한 여건 변화 속에서 지속가능발전위원회의 제67회 국정과제보고회의(2005년 10월 19일)에서는 농업용수 10% 절약 대책과 유역단위의 통합적 물 관리를 요구하게 되었다. 우리나라는 현실적으로 매년 홍수 피해가 발생하고 있지만, 다른 한편 인구밀도가 높고 1인당 가용 수자원이 상대적으로 적기 때문에 국지적 물 부족 문제를 경험하고 있다. 최근 국제적으로도 농업용수의 물 낭비 최소화와 절약 노력 및 타 분야 물 수요 증대에 대한 대응 능력 제고가 매우 중요한 과제로 부각되고 있다. 2006년 3월 멕시코에서 개최된 제4차 세계 물 포럼에서 국제 강 네트워크는 "세계 물 위기의 주범은 농경지", "농민들은 모든 물 위기 논의에서 핵심"이라고 주장하고, 전 프랑스 총리 미셀 로카르는 "...관개시설에 큰 문제점이 있고 덜 조방적 농업을 하도록 농민들을 설득해야 한다. 이는 전체 농경법을 바꾸는 문제..."(segye.com, 2006. 3. 19)라고 주장하는 등 세계 물 문제 해결을 위해서는 농업용수의 효율적 이용 관리가 중요함을 강조하였다. 본 연구는 이러한 국내외 여건 및 정책 환경 변화에 적극적으로 대처하고 물 분쟁에 따른 갈등해소 전략 수립과 효율적인 물 배분 및 이용을 위한 기초연구로서 농업용수 수리권과 관련된 법 및 제도를 분석하였다.

• Journal of Korea Water Resources Association
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• v.43 no.11
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• pp.995-1009
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• 2010

Accelerated soil erosion due to extreme climate change, such as increased rainfall intensity, and human-induced environmental changes, is a widely recognized problem. Existing soil erosion models are generally based on the gross erosion concept to compute annual upland soil loss in tons per acre per year. However, such models are not suitable for event-based simulations of erosion and deposition in time and space. Recent advances in computer geographic information system (GIS) technologies have allowed hydrologists to develop physically based models, and the trend in erosion prediction is towards process-based models, instead of conceptually lumped models. This study aims to propose an effective and robust distributed rainfall-sediment yield-runoff model consisting of basic element modules: a rainfall-runoff module based on the kinematic wave method for subsurface and surface flow, and a runoff-sediment yield-runoff model based on the unit stream power method. The model was tested on the Cheoncheon catchment, upstream of the Yongdam dam using hydrological data for three extreme flood events due to typhoons. The model provided acceptable simulation results with respect to both discharge and sediment discharge even though the simulated sedigraphs were underestimated, compared to observations. The spatial distribution of erosion and deposition demonstrated that eroded sediment loads were deposited in the cells along the channel network, which have a short overland flow length and a gentle local slope while the erosion rate increased as rainfall became larger. Additionally, spatially heterogeneous rainfall intensity, dependant on Thiessen polygons, led to spatially-distinct erosion and deposition patterns.

• Land and Housing Review
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• v.3 no.4
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• pp.343-355
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• 2012

The purpose of this paper is to propose reasonable improvements of demand estimation methods of commercial site through the case study. Thus, we investigated the problems and limitation of demand estimation methods and process applied to primary and secondary new towns in Korea. And we suggested the way to reduce error of demand estimation and to raise its objectivity. The result of case analysis is as follows; firstly, it was insufficient to consider location, hierarchy and change of land use like mixed-use development in commercial site. Secondly, improper comparable group or operated relevant index data in the same light were selected the aggregated unit requirement method such as comparative analogy method and planning guidelines. Thirdly, there were many cases that demand estimation value was amended arbitrarily, and it tends to occur a serious reliability problem. Therefore, to improve these problems and to make better use of demand estimation hereafter are required the sublation of arbitrary commercial sphere's settings, the making of comparative group considered development conditions, and putting forward objective revision basis.

• Journal of Chest Surgery
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• v.41 no.1
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• pp.49-54
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• 2008

Background: Aortic diseases tend to involve the entire aorta. Hence, there is the constant possibility of the need for a secondary operation at the remnant aorta. This study analyzed our cases of secondary aortic surgery in order to determine its characteristics and problems. Material and Method: Between April 2003 and June 2007, 12 patients (6 male and 6 female) underwent thoracoabdominal aortic replacement as a secondary aortic operation. Their clinical courses were analyzed. Four of the patients underwent lower thoracobadominal aortic replacement under the normothermic femorofemoral bypass, and the others underwent an entire thoracobdominal aortic replacement under deep hypothermic circulatory arrest. Result: There was no death or paraplegia. As local complications, there were 3 cases of wound infection and 2 cases of an immediate reoperation caused by bleeding and one case of delayed wound. revision for a contaminated perigraft hematoma. As a systemic complication, there was one case of renal insufficiency, which required hemodialysis and one case of respiratory insufficiency that needed prolonged ventilator care. The mean admission period was $30{\pm}21$ days. All the patients were followed up for $626{\pm}542$ days without reoperation or other problems. Conclusion: Using properly selected patients and a careful approach, thoracoabdominal aortic replacement can be performed safely as a secondary aortic surgery.

• Archives of design research
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• v.14 no.3
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• pp.59-68
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• 2001

The design on magazine advertisement has been developed and investigated in various fields, but the matter of properties has been inattentive in advertisement. Therefore, this study is to clarify the role of advertisement properties and the application tendency of it through the case study of the magazines for woman in Korea, and to analyze the relationship among the characteristic of manufactured goods for advertising, visual effects, copy-writing and the advertisement properties. The results of the study are as follows ; 1 . It is important to choose the discriminative property compared to the competitive company and to consider the purpose of advertisement from the beginning of idea developing. 2. Leading the photo artist to the photo working corresponding to the purpose of advertisement is critical point in advertisement design process. 3. After the photographing, it should be investigated from the designer's point of view. The presentation strategies on the application of advertisement properties are as follows, ·Conform the subject of advertisement massage. ·Choose the advertisement properties considered the relationship between manufactured goods for advertising and properties. ·Consider the properties as the supporting tool in bringing manufactured goods for advertising into relief. The pertinent application of advertisement properties is able to attract public attention and to increase the worthy of advertisement. Therefore, the prudent trial and experiment on it is needed.

• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.79-93
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• 2009

For developing the location based service which is individualized and specialized according to the characteristic of the users, the spatio-temporal pattern mining for extracting the meaningful and useful patterns among the various patterns of the mobile object on the spatio-temporal area is needed. Thus, in this paper, as the practical application toward the development of the location based service in which it is able to apply to the real life through the pattern mining from the huge historical data of mobile object, we are proposed STOMP(using Frequency of sequence and Weight) that is the new mining method for extracting the patterns with spatial and temporal constraint based on the problems of mining the optimal moving pattern which are defined in STOMP(F)[25]. Proposed method is the pattern mining method compositively using weighted value(weights) (a distance, the time, a cost, and etc) for our previous research(STOMP(F)[25]) that it uses only the pattern frequent occurrence. As to, it is the method determining the moving pattern in which the pattern frequent occurrence is above special threshold and the weight is most a little bit required among moving patterns of the object as the optimal path. And also, it can search the optimal path more accurate and faster than existing methods($A^*$, Dijkstra algorithm) or with only using pattern frequent occurrence due to less accesses to nodes by using the heuristic moving history.

• Journal of Internet Computing and Services
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• v.19 no.1
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• pp.49-66
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• 2018

This research explores a value chain structure of VR-AR media including user's perception, uses, and evaluation. The purpose of this research focused on factor analysis and the relationship among user's VR-AR adoption motivations and utilities. This research explores correlation between personal value and using motivation. This study was to identify the value structure of respondent on VR-AR usages based on means-end chain theory. The research used structured APT laddering questions and 251 data was analysed. Through such analysis, category difference by stage and relationship difference were identified and hierarchical value map was compared. There are four different value ladders: first is attributes, functional consequences, psychological consequences, and final value. This study is based on the analysis of the value chain structure factors that affect VR and AR use behavior (attributes, functional benefits, psychological benefits, use value), 'Hierarchical Value Map' between users' The purpose of the model is to construct a model. For this, 'means-end chain theory' was applied to measure the causal relationship between personal value and VR related use behavior. In order to solve this research problem, 135 people were analyzed through the structured questionnaire using the AR and VR content fitness measure and the second APT laddering, and the use of VR-AR : 1) Functional benefits; 2) Psychological benefits; 3) Means to reach value, 4) Objective value chain structure was identified. The results show that VR users tried to smooth the social life through the new virtual reality audiovisual element, the newness of experience, fun, and pleasure through the departure of reality, vividness of experience, and leading fashion. The AR fitness was a game and a new program, and the value of interacting with other people and the value of 'periwinkle' played an important role through the vividness and peripheral interaction of AR, It was an important choice. The important basic values of users' VR and AR selection were correlated with psychological attributes of interaction with others, achievement, happiness and favorable values.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.426-439
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• 1999

본 논문에서는 웹(World Wide Web)에서 사용자가 손쉽고 편리하게 이용할 수 있는 멀티미디어 대중교통 안내시스템 개발 경험을 소개한다. 개발된 시스템은 클라이언트와 서버 시스템, 경로탐색 시스템, 교통정보 저장 시스템, 노선 및 정류장 관리 시스템으로 구성되어 있다. 클라이언트에서 작동되는 사용자 인터페이스는 직관적으로 이해가 쉽고, 사용이 편리하며 인터액티브한 멀티미디어 대중 교통안내 서비스를 제공한다. 서버 시스템은 교통정보 수집 시스템으로부터 입력되는 데이타와, 경로탐색 시스템, 교통정보 저장 시스템과 연동되어 클라이언트의 요구사항을 처리하고 그 결과를 사용자에게 돌려준다. 수정된 A* 알고리즘을 이용하는 경로탐색 시스템은 최적경로를 탐색하며, 교통정보 저장 시스템은 현재 교통상황, 정류장, 노선, 지도 등의 정보를 저장한다. 노선 및 정류장 관리시스템은 시스템 관리자가 노선 또는 정류장 관리를 서버 화면의 지도상에서 효율적으로 수행할 수 있는 도구이다. 본 논문에서 다루는 대중교통 안내시스템은 Java로 구현하였기 때문에 확장과 이식이 용이하며, 시스템 유지보수 비용이 적게 드는 장점을 가지고 있다. 그리고, 웹 브라우저가 동작되는 환경에서는 어디서나 쉽게 접근이 가능하며 향후 구축될 Intelligent Transportation Systems(ITS)의 한 모듈로써 바로 작동될 수 있을 뿐만 아니라, 현재 인터넷상에서 제공되는 다양한 서비스와도 연동이 가능하다.Abstract This paper introduces our experience for developing a public transportation guidance system, which facilitates the World-Wide Web(WWW) to provide users with easier access and use. The proposed system is composed of four subsystems: client/server system, path search system, traffic data storage system, and traffic raw-data management system. The user interface in clients utilizes Java to furnish users with multimedia data accessibility and interactivity. The server processes clients' requests based on the traffic data coming from remote sensing devices and interacts with the path search system and traffic data storage system to provide users with the results. The path search system, which uses a modified A* algorithm, produces optimal solutions based on dynamic traffic data. The traffic data storage system stores the current traffic information together with the geographical information about the b$us_way routes. The traffic raw-data management system is a graphical user interface which enables the system manager to handle the traffic information easily on the map in the terminal screen. The system has considerable benefits such as portability, scalability, and flexibility since it is implemented using Java. Also, it can be extended to an integrated Intelligent Transportation Systems(ITS) which includes a variety of information on the Internet as well as traffic information.n.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5314-5324
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• 2015

The present study was intended to measure the relationship between job stress and job satisfaction among nurses working for a general hospitals. The self-administered questionnaires were given to 312 nurses during the period from February 25 to March 16, 2013. As a results, the level of job satisfaction of subjects was significantly lower in high group than low group in job demand, but it was significantly lower in low group than high group in job control, supervisor support and coworker support. In correlations, job satisfaction were found to be in a negative correlation with job demand, whereas in positive correlation with job control, supervisor and coworker support. In logistic analysis, the odds ratio of job satisfaction on job demand were significantly increased in the high group than in low group, but job control supervisor and coworker support were significantly decreased in the high group than in low group. In hierarchial multiple regression analysis, the affecting factors to the job satisfaction was selected variables such as educational background, work station, subject satisfaction of work, career choice motives, turnover experience, job stress contents(job demand, job control, supervisor support and coworker support). especially, job stress contents was significantly increased of explanatory power of job satisfaction. It suggested that the level of job satisfaction got more power by addition of job stress contents.