• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.757-759
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• 2004

무선 통신 기술이 급속히 발전하면서 이동 중 데이터 통신이 가능하도록 하기 위한 연구가 활발하게 이루어지고 있다. 본 논문에서는 효율적인 이동성 제공 방안으로 멀티캐스트 기반 이동성 제공 방안을 제안하고 모의실험을 통하여 TCP 트래픽에 대한 성능을 분석하였다. 본 논문에서 제안한 방안은 이동 단말이 외부 도메인 내에서 핸드오프 시 자신의 위치 갱신을 멀티캐스트 그룹에 조인하는 방법으로 바인딩 갱신에 따른 추가적인 신호를 지역 내에서 처리함으로써 Mobile IPv6와 Hierarchical Mobile IPv6 보다 TCP 처리율을 높임을 알 수 있었다.

• Journal of the Korean Society for Library and Information Science
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• v.34 no.3
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• pp.5-23
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• 2000

The purpose of this study is to explore ways to imporve bookmobile operations by investigating bookmobiles' operating status and users' behavior in DaeJeon City. Concerning the bookmobiles operated in 32 areas of DaeJeon City, the suitability of visiting area and staying hours, the correlation between users' circumstances and lending aspects, the effects of bookloan shop in the same area, etc. are analyzed, and for the improvement of bookmobile operations, the utilization of volunteers, the connection with the main libraries' collection, the development of service programs, the strengthening of publicity activities, etc. are proposed.

• Journal of the Korean Regional Science Association
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• v.32 no.1
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• pp.83-103
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• 2016

This study aims to analyze the determinants of residential location choice for the inter-urban migrants in the Seoul metropolitan area. In doing so, we have built a discrete choice model, using household sample data from the 2010 Korea Population and Housing Census. We classified households, which made a intra-urban movement during the last five years, into four groups: 1) movers from Seoul (central city) to Gyunggi-Incheon (suburban), 2) movers from Gyunggi-Incheon to Seoul, 3) Intra-Seoul movers, and 4) intra-Gyunggi-Incheon movers. The analysis findings can be summarized as follows. First, significant differences in the determinants of residential location choice were found among different types of movers. Second, movers from Gyunggi- Incheon to Seoul were likely to choose small housings with fewer rooms, indicating that their housing choices were forced rather than voluntary due to high housing prices in Seoul. Third, all types of movers have a high preference for the neighborhood with a good accessibility by public transit including subway. Lastly, neighborhood amenity was also an important attracting factors for the intra-urban migrants in Seoul.

• Journal of Internet Computing and Services
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• v.21 no.1
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• pp.71-78
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• 2020

Recently, as the issue of gentrification emerges, it becomes important to understand the dynamics of local commercial district, which plays the important role for facilitating the local economy and building the community in a city. This paper attempts to provide the framework for systemically analyzing and understanding the local commercial district. Then, this paper empirically analyzes the patterns of sales and flow of floating population by focusing on two representative local commercial districts in Seoul. In addition, the floating population data from telecommunication bases is further modeled with Markov chain for systemically understanding the local commercial districts. Finally, the transition patterns and consumption amounts of floating population are comprehensively analyzed for providing the implications on the evolutions of local commercial districts in a city. We expect that findings of our study could contribute to the economic growth of local commercial district, which could lead to the continuous development of city economy.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.38-42
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• 2011

토석류는 산간지역에서 발생할 수 있는 가장 위험한 자연재해 중 하나로 입자-유체 혼합물인 토석류가 중력에 의해 매우 빠른 속도로 이동하는 현상을 의미한다. 산간지역에서의 토석류 발생은 도로의 횡단 배수 구조물의 통수능을 저하시키게 되며 그 결과 도로의 유실 등 막대한 피해를 발생시킨다. 잠재적인 토석류 발생 지역에서의 피해 저감을 위해서는 진보된 설계 기준이 마련되어야 하며 이를 위해 토석류의 횡단 배수구조물 내에서 토석류의 동적 거동 특성을 파악하는 것이 선행되어야 할 것이다. 이번 연구에서는 수리 실험을 통하여 횡단 배수구조물 내에서 토석류의 퇴적 특성을 파악하고자 한다. 수리 실험 장비는 폭이 일정한 사각형 수로로 접근 수로와 하류부 수로로 구성되어 있으며 접근수로의 상단부에서 일정한 유량의 토석류를 연속적으로 유입시켜 경사가 급변하는 하류부 수로 내에서의 토석류 퇴적 특성을 파악하였다. 실험 결과로 토석류의 거동 특성은 토석류의 체적 농도, 입자의 특성, 그리고 접근수로와 하류부 수로의 바닥 경사에 종속됨을 정량적으로 알 수 있었다. 또한, 토석류의 체적 농도나 수로 바닥경사 등과는 상관없이 토석류의 퇴적은 하류부 수로의 종단부인 자유 낙하 지점에서부터 시작되었고 시간이 경과함에 따라 퇴적 지점이 접근 수로 쪽으로 이동하며 퇴적량이 크게 증가하는 현상을 보였다. 이 때, 하류부 수로 내 퇴적된 토석류는 약 $12{\sim}15^{\circ}$의 경사를 보였다.

• Journal of the Korean Geographical Society
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• v.41 no.5 s.116
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• pp.582-599
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• 2006

Due to the growing popularity of mobile information technology, more people, especially in the general public, have access to computerized geospatial information systems for wayfinding tasks or urban navigation. One of the problems with the current services is that, whether the users are exploring or navigating, whether they are travelers who are totally new to a region or long-term residents who have a fair amount of regional knowledge, the same method is applied and the direction are given in the same way. However, spatial knowledge for a given urban region expands in proportion to residency. Urban navigation is highly dependent on cognitive mental images, which is developed through spatial experience and social communication. Thus, the wayfinding service for a regional community can be highly supported, using well-known regional places. This research is to develop the framework for urban navigation within a regional community. The concept of communal ontology is proposed to aid in urban regional navigation. The experimental work was implemented with case study to collect regional landmarks, develop the ontological model and represent it with formal structure. The final product of this study will provide the geographical information of a region to the other agent and be the fundamental information structure for cognitive urban regional navigation.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.11
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• pp.545-561
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• 2007

Location management and message delivery protocol is fundamental to the further development of mobile agent systems in a multi-region mobile agent computing environment in order to control mobile agents and guarantee message delivery between them. However, previous works have some problems when they are applied to a multi-region mobile agent computing environment. First, the cost of location management and message delivery is increased relatively. Second, a tracking problem arises. finally, cloned mobile agents and parent-child mobile agents do not get dealt with respect to location management and message delivery. In this paper, we present a HB (Home-Blackboard) protocol, which is a new location management and message delivery protocol in a multi-region mobile agent computing environment. The HB protocol places a region server in each region and manages the location of mobile agents by using intra-region migration and inter-region migration. It also places a blackboard in each region server and delivers messages to mobile agents when a region server receives location update form them. The HB protocol can decrease the cost of location update and message passing and solve the tracking problem with low communication cost. Also, this protocol deals with the location management and message passing of cloned mobile agents and parent-child mobile agents, so that it can guarantee message delivery of these mobile agents and pass messages without passing duplicate messages.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.815-821
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• 1994

Short-term fading in a mobile radio channel is mainly caused by multipath reflected wave by local scatterers or natural obstacles surrounding a mobile unit. In this paper, we analyze probability density function(PDF), level crossing rate(LCR) and widths and depths of fades for the measured field strength data in Seoul and Daejeon areas. As a result, the satatistical distribution of signal variations within any small area with the constant mean value becomes the Rayleigh distribution The variation of fade depths is small regardless of the environment such as urban, suburban. etc. However, the variation of fade widths is large with the change of circumstantial structures and environment. the maximum level crossing rate is obtained near the mean value.

• KOREAN POULTRY JOURNAL
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• v.40 no.6 s.464
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• pp.101-103
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• 2008

본고에서는 AI 종식이후 농가들이 재입식 절차요령에 대한 궁금증을 풀어주고자 "가축질병 위기대응 실무메뉴얼" 에 실린 사후관리와 재입식 요령을 바탕으로 정리하여 게재하였다. HPAI가 발생한 위험지역 내에서 다시 재입식을 하기 위해서는 최소한 3개월 정도가 소요된다. 즉, AI의 최대 잠복기가 3주이기 때문에 최종 살처분이 이루어진 이후 추가 발생이 없으면 3주후에 위험지역은 경계지역으로 전환되고, 이후 1달간의 상황을 지켜본 후 이상이 없으면 이동제한 조치가 추가로 해제된다. 이동제한 조치가 풀렸다고 해서 AI발생지역에서 재입식이 가능한 것은 아니다. 이동제한 조치가 풀린뒤 21일간의 입식시험을 거쳐야 하고 시험사육뒤 검역원에 21일간의 정밀검사를 받은 후에 비로소 입식을 할 수 있다. 이 모든 것은 추가 발생이 되지 않는다는 전제에 이루어진다. 따라서 지난 5월 12일 경남 양산지역에서 마지막 발생되었으므로 3km이내 가금산물을 모두 폐기처리 한 5월 22일부터 최소 3개월이 흐른 8월 20일 경에야 비로소 입식을 할 수 있을 전망이다. AI 청정화도 이 시기 전후에 이루어질 것으로 보인다.

• Journal of the Korean Regional Science Association
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• v.39 no.3
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• pp.49-63
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• 2023

This study investigates the occupational mobility patterns of young wage employees at the local level of the labor market and empirically examines the interplay between worker-level and local labor market-level determinants between 2010 and 2020. The 4th to 14th waves of the Youth Panel 2007 were integrated with the Korea Network for Occupations and Workers and the Local Area Labor Force Survey for estimation using hierarchical linear model. Our results indicate that Gross Regional Domestic Product per capita is key determinant of occupational upward mobility. Also, Estimates of employment size, population density, and the unemployment rate of local labor market have different effects depending on the education level and occupational location of youth workers, suggesting that the effects of structural factors of local labor market may not be distributed equally among all youth wage workers. The findings have policy implications regarding the recent rise in inequality and polarization in local labor markets.