• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.90-93
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• 2016

본 논문에서는 Sub-GHz band module을 Drone에 탑재하여 Drone과 전원공유로 Node(Drone)간 Low power and Long range Ad-hoc communication을 할 수 있는 방법을 제안하고자 한다. 또한 이동성이 있는 Node(Drone)의 Low power and Long range communication을 위해서 Drone에 적합한 Asynchronous MAC (medium access control) protocol을 비교분석하여 적용하였다. 본 고에서는 무선 센서 네트워크의 응용 범위가 확대되면서 고정된 인프라 없이 Drone간에 실시간 정보를 통신 할 수 있게 하고 사람의 이동이 어렵고 위험한 재난지역, 방사선노출지역 또는 우천시 유인기와 사람의 접근이 불가능한 지역을 Drone이 대신 이동하여 인명피해를 줄이고 안전하게 필요한 데이터를 수집하여 상황관제실로 전송하는 서비스를 제공하고자 한다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.123-124
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• 2003

산업의 발달로 인한 대기오염의 심각화 현상은 국지적인 현상을 뛰어넘어 지역적인 문제로까지 확산되고 있다. 황사 현상의 경우만 하더라도 이제는 한국, 중국, 일본 만의 문제가 아닌 미국 서부해안까지도 그 영향을 받는 것으로 보고 되고 있다. 이처럼 국가간 장거리 이동오염물질의 관측 및 평가에 즈음하여 우리나라에서도 중국 및 일본과 함께 동북아시아 지역에서의 장거리 이동오염물질에 대한 연구를 활발히 진행하고 있다. (중략)

• Journal of the Korean association of regional geographers
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• v.11 no.2
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• pp.169-186
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• 2005

This paper has focused on the geographical patterns of migrations and the influence of housing value(apartment) per pyung on the migrations within the one city(Seoul) for 1995$\sim$2003. The migration flows which are composed of the origin, the destination and the number of migrants, are examined at the administrative gu and dong level. As most migrations occur among adjacent gus and dongs, short-distance migration is prominent But there is a tendency for the short-distance migrations to occur between specific regions. Since the economic crisis of 1997 out of which Korea was rescued by IMF, differentiation of housing price is so evident that residental relocation is selective among dongs. It seems that the differentiation of housing price has begun to facilitate the relocation of households. Certain social groups are excluded from high-quality residences, as they cannot afford the high price. The number of migrants between dongs is closely related to the variation of the housing value per pyung within dongs. The short-distance migration may reflect this phenomena simultaneously. It seems that the intra-urban migrations in Seoul play a important role to produce and reinforce the residential segregation.

• Journal of the Korean Regional Science Association
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• v.35 no.2
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• pp.49-57
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• 2019

The young generation in life cycle that social position is rapidly changing is play an important role in a regional development because they can increase social and natural population in the region. This study analyzed the relationship between the movement of young generation and the regional characteristics including housing market characteristics in Seoul. As the results, the movement of young generation was influenced by commuting distance and location of jobs as the gravity model has suggested. In addition, housing supply and housing price (or Jeonse price) is an important factor for the movement of young generation. It can be inferred that the more price gap such as Jeonse price and housing supply gap are increased, the more out-migration of young generation in Seoul is increased. However, the housing demand of young generation in employment centers will be increased because jobs contribute to increasing the inflow of young people. Therefore, the policies of central and Seoul government that supply housing in job rich and high accessibility areas are needed for young generation. In addition, if public housing and affordable housing are supplied in the other areas, it can contribute to reduce the out-migration of young people in Seoul.

• Journal of the Korean Regional Science Association
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• v.40 no.2
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• pp.21-38
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• 2024

Understanding the interrelationship between regional population dynamics and cultivated land is crucial for promoting regional economic vitality and enhancing food security. While prior research often addressed population migration and changes in crop area separately, this study employs a Panel Vector Auto Regression Model to examine the dynamic interaction between regional population shifts, changes in crop area, and the influx of foreign workers in agriculture. The results reveal a reciprocal relationship between population influx and crop area, indicating a negative impact on each other. Moreover, the analysis demonstrates that an expansion in crop area, particularly in field cultivation, significantly correlates with an increase in foreign workers. These findings underscore the mutual influence of labor shortages and diminished land availability in agriculture, with the influx of foreign workers potentially offering a positive impact on addressing structural challenges in rural areas.

• Journal of Labour Economics
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• v.41 no.2
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• pp.61-88
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• 2018

This paper examines the impact of internal migration on wage growth among college graduates using Propensity Score Matching methods. We define migration as moving between Seoul Metropolitan Area (SMA) and non-SMA based on the locations of graduates' first and second jobs. We also take the direction of migration into account for examining the wage premium in SMA. In order to estimate the impact of migration on wage growth, we use the Graduate Occupational Mobility Survey (2010GOMS) coupled with other supplementary data such as College Scholastic Ability Test score and local characteristic variables. The results reveals that graduates moving from SMA to non-SMA do not experience significant wage growth. However, we find that graduates moving from non-SMA to SMA experience an increase in their monthly wage about 170,000~186,000 KRW on average (9.5~10.3% of their monthly wage on the first job).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8B
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• pp.762-770
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• 2004

With rapid advances in wireless communication technologies and with the advent of the smaller and high-performance mobile handsets nowadays, many researches are actively performed for providing seamless communications while mobile nodes are roaming around. As real-time application programs are more prevalent, it is very important to manage mobility of mobile nodes efficiently. In this paper, we propose a localized mobility support scheme that is based on the Mobile IPv6 by IETF. The proposed scheme enhances functionalities in mobile nodes and only uses signaling messages of Mobile IPv6. The performance of the proposed scheme is evaluated through analytical model and simulations. According to the results of the evaluation, the proposed scheme provides better performance than Mobile IPv6 in terms of packet losses and TCP throughput by localizing the binding update messages inside the foreign domain during handoffs and reducing binding update time.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.438-449
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• 2014

This paper is aimed to study on residential choice after retirement. For this reason, this study is analyzed in three aspects ; the factors of residential choice, preferred house types and scales, the characterization of residential mobility. This study reached several conclusions. Firstly, Korea baby boomers are likely to select their residence with different factors after retirement, and they are likely to choose their residence in the view of comfort and convenience. Secondly, apartment resident ratio is shown to be reduced after retirement, and the preference for the country houses and town houses is shown to be increased. Thirdly, the baby boomers don't reduce their residential scale in batches, while they are to show a different appearance depending on the retention scale of housing. Fourthly, The 62.4% of Korean baby boomers is to plan move their residences after retirement, 52.3% of movers, more than half of them, is to go to the different residential area. Fifth, it is analyzed that different variables are to influence on the local and regional of residential mobility of the baby boomers in Korea.

• Journal of KIISE:Software and Applications
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• v.35 no.5
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• pp.281-287
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• 2008

Data transfers occur during the execution time of a Java program, from constant to variable, from variable to other variable and so on. Data are located in memory and hence data transfer requires access to memory. As memory access generates both time delay and energy consumption it is absolutely necessary to know the data transfer overheads incurred among different paths not only to write an efficient program but also to build a high-performance Java virtual machine. In this paper we classify Java memory into three different regions, constant, local variable, and field, and then investigate data transfer overheads among these regions. The result says that the transfer between local variables incur the least overhead usually, while the transfer between fields incur the most. The difference of overheads reaches up to a double. Optimization techniques like JIT reduces the data transfer overhead dramatically. It is observed that the overhead is reduced from 14 to 27 times for the case of Hotspot JVM.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.341-341
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• 2020

서울시는 '10년, '11년, '18년의 기록적인 호우로 인해 막대한 재산피해를 기록하였다. 이로 인해 서울시는 수재해 최소화 대책의 필요성을 인지하여 방재시설물 확충 등의 구조적 대책과 함께 침수지역 예측, 호우 영향 예보와 관련된 비구조적 대책 수립을 위해 노력하고 있다. 그 일환으로 '18년에 『서울시 강한 비구름 유입경로 및 침수위험도 예측 용역』을 수행하였으며 이를 통해 레이더 기반의 비구름 이동경로 추정 기술, 침수시나리오 기반의 침수위험지역 추정기술 등을 적용한 서울시 도시침수 예측시스템을 개발하였다. 그러나 침수피해에 선제적으로 대응하기 위해서는 실시간으로 예측강우정보를 생산하고 이를 통해 침수위험지역을 추정하는 기술이 필요하다. 이에 본 연구를 통해 예측강우정보 생산 기술 적용, 예측강우정보를 이용한 실시간 침수위험지역 추정 기술 개발을 수행하여 서울시 도시침수 예측시스템을 고도화하였다. 예측강우정보의 경우 현재 기상청에서 광역 단위 호우특보 및 읍면동 단위 동네예보를 통해 제공되고 있지만, 풍수해 업무에 적용하기에는 제한적이며, 실시간 침수위험지역 추정의 경우 침수해석모델의 모의시간, 라이센스 등의 문제로 인해 한계를 보이고 있는 실정이다. 따라서 본 연구에서는 레이더 실황강우정보를 활용한 이류모델 기반의 예측강우정보 생산 기술을 적용하여 풍수해 업무 적용이 용이하도록 하였으며, 예측강우정보를 이용한 최적 침수시나리오 추정 기술 개발을 통해 실시간 침수위험지역 추정이 가능하도록 하였다. 서울시 도시침수 예측시스템은 25개 자치구를 대상으로 강우량, 호우이동경로, 침수 정보를 제공하고 있다. 강우정보는 기상청 및 SK-TechX 기반의 10분 및 1시간 단위 AWS 관측정보, 이류모델 기반 10분 단위 레이더 예측정보, 국지예보모델 기반 1시간 단위 LDAPS 예측정보를 제공하며. 호우이동경로는 레이더 실황강우정보와 LDAPS 바람장을 이용하여 서울시 및 수도권 지역의 10분 단위 1시간 예측경로를 제공한다. 침수정보는 실시간으로 레이더 예측강우정보를 이용하여 최적의 침수시나리오를 추정하여 격자 단위 상세 침수정보와 시군구 단위 침수위험지도를 제공한다. 본 시스템을 통해 실시간 침수위험지역 확인이 가능해짐에 따라 서울시의 효율적인 풍수해 업무 지원이 가능할 것으로 판단된다.