• 지역연구
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• 제15권2호
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• pp.75-102
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• 1999

This paper attempts at analyzing the urban dynamics in Northeast Asia by looking at major forces transforming the regional structure of Northeast Asia. Trade and foreign direct invest-ment are identified as two principal channels of increasing economic interdependence in the region. In addition, macro development strategy and infrastructure policy are another set of determining factors for changes in the regional structure of Northeast Asia. To examine the role of cities and inter-city linkages, the paper first tries to identify major urban centers and urban hierarchy in Northeast Asia. Secondly, it examines the prospects for inter-city network formation. Against these anticipated changes in the regional structure and inter-city networks in Northeast Asia, the paper discusses about the future of Korea as well as the role of Koran cities in the regional economy of Northeast Asia.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4759-4780
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• 2017

Full Dimension multiple input multiple output (FD-MIMO) architecture employs a planar array design at the Base Station (BS) to provide high order multi-user MIMO (MU-MIMO) via simultaneous data transmission to large number of users. With FD-MIMO, the BS can also adjust the beam direction in both elevation and azimuth direction to concentrate the energy on the user of interests while minimizing the interference leakage to co-scheduled users in the same cell or users in the neighboring cells. In a typical highly populated macrocell environment, modelling the elevation angular characteristics of three-dimensional (3D) channel is critical to understanding the performance limits of the FD-MIMO system. In this paper, we study the throughput performance of FD-MIMO system with varying elevation angular spread and inter-element spacing using a 3D spatial channel model. Our results show that for a typical urban scenario, horizontal beamforming with correlated antenna spacing achieves optimal performance but by restricting the spread of elevation angles of departure, elevation beamforming achieves high array gain with wide inter-element spacing. We also realize significant gains due to spatial array processing via modelling the elevation domain and varying the inter-element spacing for both the transmitter and receiver.

• 국토계획
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• 제54권3호
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• pp.15-26
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• 2019

The development of science and transportation technology leads to the increase of inter - city networks that play an important role in urban growth. Overall, numerous studies based on network theory pay attention to positive effects of urban network on urban growth. However, some studies have pointed out the negative effects of inter-city interactions such as straw effects. This implies that the network between cities may not be positively correlated with urban growth, and that the direction of the influence may vary from a certain threshold, such as the marginal utility curve. In this context, the purpose of this study is to measure the impacts of network with central city on urban growth in the capital region and examine the relationship between urban network and growth. Two multiple regression models are employed with changes in population and employment as dependent variables. The urban network index and other control variables are used as independent variables. Especially, the urban network indexes are used in quadratic forms to examine non linear relations with urban growth such U-shape or an inverted U-shape. The results show that the relationships between networks with the central city and urban growth are not a simple linear, and the influence can be changed from the critical point.

• 대한원격탐사학회지
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• 제17권2호
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• pp.111-119
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• 2001

This study analyzes time variability of the normalized difference vegetation index (NDVI), the leaf area index (LAI) and surface temperature (Ts) estimated from AVHRR data collected from across the Korean peninsula from 1981 to 1994. In the present study, LAI defined as vegetation density, as a function of NDVI applied for the vegetation types and Ts defined by the split-window formulation of Becker and Li (1990) with emissivity of a function of NDVI, are used. Results of the inter-annual, intra-annual and intra-seasonal variabilities in Korea show: (1) Inter-annual variability of NDVI is generally larger in the southem and eastern parts of the peninsula than in the western part. This large variability results from the significant mean variation. (2) Inter-annual variability of Ts is larger in the areas of smaller NDVI. This result shows that the NDVI play a small role in emissivity. (3) Inter-annual variability of LAI is larger in the regions of higher elevation and urban areas. Changes in LAI are unlikely to be associated with NDVI changes. (4) Changes in NDVI and Ts are likely dominant in July and are relatively small in spring and fall. (5) Urban effect would be obvious on the time-varying properties of NDVI and Ts in Seoul and the northern part of Taejon, where NDVI decreases and Ts increases with a significant magnitude.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.591-592
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• 2007

• 한국지역지리학회지
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• 제21권1호
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• pp.39-61
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• 2015

이 논문은 도시 연계성에 관한 문헌들을 검토한 후 다중심도시지역의 개념과 분석기법을 제시하고, 이를 활용하여 영남권 도시들 간 화물통행량을 분석하여 도시 연계성과 다중심성을 고찰하고자 한다. 분석 결과, 영남권의 도시 네트워크는 흐름의 대칭성(즉 유입과 유출 통행량의 차이)에 있어 도시별로 상당한 차이를 보이지만, 엔트로피 지수로 보면 상대적으로 분산적인 흐름을 나타내고 있다. 또한 지배력 지수로 보면, 영남권 도시네트워크는 수도권에 비해 훨씬 다중심적(즉 비계층적) 특성을 보인다. 그러나 부산과 울산은 상대적으로 지배력 지수가 높고 이 도시들에 의존하는 연계도시들이 많은 반면, 대구는 지배력 지수가 상대적으로 낮고, 의존적 연계도시들의 수도 적게 나타난다. 결론적으로 제조업 부문별 화물 네트워크는 1위 도시인 부산을 중심으로 흐름이 집중하는 양상을 보이지만, 전반적으로 영남권 도시지역은 다중심도시지역의 특성을 상당히 보인다는 점에서, 다중심적 지역발전 정책이 권장될 수 있다.

• 한국환경생태학회:학술대회논문집
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• 한국환경생태학회 2006년도 정기총회 및 학술논문발표회
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• pp.157-161
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• 2006

• 한국항만학회지
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• 제8권1호
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• pp.49-63
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• 1994

The introduction of high speed railway system a significant impact on the conventional inter-urban transport systems by inducing a significant traffic from the existing modes as well as generating a new traffic. It is also closely related to intra-urban transport systems as the inter-urban traffic has its origin and destination in a city. In the context of mode choice, for high speed transport systems, it has been argued that the accessibility is the most important attribute conceived by users. Thus this study attempts to analysis the importance of the accessibility for the planned high speed railway systems particularly with respect to the location of Busan Station. For this Stated-Preference approach, which is considered appropriate for such study, is adopted, and disaggregate binary logit models for mode choice between the high speed railway and air service in Busan-Seoul corridor are developed. The elasticities for cost and service variables are also derived. The results disclose that cost is the most important which is inconsistent with most previous studies ; accessibility has considerable impact on the choice ; and frequency however has a little impacts. Concerning location of the high speed railway station the results suggest that the longer the access distance is, the more important the accessibility is. This implies that the connection of reliable access transport services such as underground are essential between the terminal and urban center.

• 대한교통학회지
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• 제13권2호
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• pp.5-18
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• 1995

The aims of this study is to analyzed determinants of work-trip satisfaction degrees in six major metropolitan areas. and to derive urban policy implications. As is well -known, the main determinant of travel satisfaction degree is travel time. However, other factors such as travel mode, psychological factor, and priority in residential location choice are also significant ones. The findings imply that transportation problems are deeply related with housing problems in urban areas. This results provides an evidence of the nature of urban problems, i.e. inter-connectiveness among urban problems. Therefore, this study emphasizes that all urban problems should be treated with careful consideration of other related-urban problems.

• Journal of Communications and Networks
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• 제16권6호
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• pp.645-655
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• 2014

Latency, an identified element of Internet protocol (IP) mobility protocol execution, can reduce handover performance in mobile networks. Although the performance can be improved by applying an effective network-based IP mobility scheme in place of the traditional host-based alternatives, the existing inter-domain extensions of network-based IP mobility continue to suffer from an extended handover latency. This paper proposes a new inter-domain network-based IP mobility scheme based on node movement prediction. The proposed scheme accelerates the handover by preparing the future domain of the mobile node in a proactive manner. Analytical and simulation-based evaluations confirm improved performance of the proposed scheme in terms of handover latency and packet loss compared with existing schemes.