• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.167-177
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• 2010

This study proposes a methodology for assessing the improvement of network connectivity of transport hubs. Extending a previously developed model that measures the connectivity of a node in transportation networks, we define two quantities called the supplied connectivity and the experienced connectivity. Using these quantities, we provide a systematic procedure for analyzing the network connectivity of a transport hub and also suggest criteria for determining whether a given project is effective in improving the network connectivity of the transport hub. The application of the methodology to a test site produces reasonable results, and as such it is expected that the methodology can be used for various transport hubs in the national road network. Once enough data from the application of the methodology are accumulated, a further study on the level of service in terms of network connectivity needs to be followed.

• Journal of Korean Society of Transportation
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• v.28 no.3
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• pp.85-98
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• 2010

As transit networks are becoming more multimodal, the concept of connectivity of transit networks becomes important. This study aims to develop a quantitative model for measuring the connectivity of multimodal transit networks. To that end, we select, as evaluation measures of a transit line, its length, capacity, and speed. We then define the connecting power of a transit line as the product of those measures. The degree centrality of a node, which is a widely used centrality measure in social network analysis, is employed with appropriate modifications suited for transit networks. Using the degree centrality of a transit stop and the connecting powers of transit lines serving the transit stop, we develop an index quantifying the level of connectivity of the transit stop. From the connectivity indexes of transit stops, we derive the connectivity index of a transit line as well as an area of a multimodal transit network. In addition, we present a method to evaluate the connectivity of a transfer center using the connectivity indexes of transit stops and passenger acceptance rate functions. A case study shows that the connectivity evaluation model developed in this study takes well into consideration characteristics of multimodal transit networks, adequately measures the connectivity of transit stops, lines, and areas, and furthermore can be used in determining the level of service of transfer centers.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.129-139
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• 2010

This study proposes a model for measuring the connectivity of nodes in road networks. The connectivity index between two nodes is characterized by the number of routes, degree of circuitousness, design speed, and route capacity between the nodes. The connectivity index of a node is then defined as the weighted average of the connectivity indexes between the node and other nodes under consideration. The weighting factor between two nodes is determined by the travel demand and distance between them. The application of the model to a toy network shows that it reasonably well quantifies the level of connectivity of nodes in the network. If flow of rail networks can be measured in the same scale as that of road networks and the capacity of rail links can be estimated, the model proposed in this paper could be applied to intermodal transportation networks as well.

• Journal of the Korean association of regional geographers
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• v.21 no.1
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• pp.1-20
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• 2015

This paper is to provide some suggestions to complement and extend theory of network city, and to consider preliminarily its applicability for development of the Yeongnam region, exploring its normative implications for urban and regional policy and its significance of empirical research. In order to resolve some limitations and problems of network city theory and of empirical research, we need to reconsider systematically analysis methods, to extend indices of connectivity, to reconfirm normative characters inherent in network city theory, to suggest the constitution of cooperative governance, and to develop policies for embedding functional connectivity into internal community. In a preliminary analysis of Yeongnam region on the basis of network city theory, it is not clear whether the urban system of the region is entirely a type of network city, even though it seems to be close to network city. However, in order for the Yeongnam region to orient towards network city, we can point out importance of policy issues such as expansion of transportation and communication infrastructure, strengthening of economic connectivity, constitution of cooperative governance, and local embeddedness of functional network within the region.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.4
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• pp.718-742
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• 2014

The capitalist economic process of glocalization and development of transportation and communication technology have led us to the significance of network city as well as concepts of global city, megacity region, etc. Network city theory pursues development of both individual cities and of the region of those cities through strengthening of mutual connectivity among them with specialized industries. On the basis of network city theory, this paper is to analyze specialized industries of cities and connectivity among them in the Youngnam region in S. Korea. It uses the methods of locational quotient, locational Gini coefficient, and shift-share method to analyze specialized industries of cities, and correspondence analysis, global and local Moran's I to examine connectivity among cities. As results, it can be identified that each city in the Youngnam region has its own specialized industries different from each others, but it seems not easy to grasp the overall extent of connectivity among them, partly because of the limitations of applied analysis methods and partly because of a lack of connectivity among cities themselves.

• Journal of Korea Technology Innovation Society
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• v.16 no.4
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• pp.883-912
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• 2013

This study examines network compositions of convergent research relationships in the field of high-tech convergence technology and investigates the relational linkages among various research fields. A network analysis was performed to evaluate the High-Tech Convergence Technology Development Program, a convergent research funding program of the National Research Foundation of Korea (NRF); the dataset covered the 2009-2011 period. The analytical results reveal the hidden network structure of convergent research relationships and demonstrate that the formation of convergent research might be enhanced by interdependent pressures placed on various research fields but also by accumulated research capabilities that each of these fields possessed and which could be used to converge specialized and heterogeneous research areas and interests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.559-569
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• 2016

This study examined flow between regions based on the spatial structure of the territory and characterized the flow patterns by analyzing regional networks via transportation connectivity. To accomplish this, transportation connectivity of the entire nation was examined using 2010 national express bus OD data from the Korea Transport Database. After the initial analysis, 2010 car OD data describing networks in seven regions (125 cities and districts), Gangwon-do, Gyeongsangnam-do, Gyeongsangbuk-do, Jeollanam-do, Jeollabuk-do, Chungcheong-do and Seoul, were analyzed to identify transportation connectivity. The results revealed that Korea has strong triangular-belt-shaped transportation connectivity that connects among metropolitan areas in the Jeolla and Gyeongsang areas. Particular zones are set by regional characteristics and functional connectivity for each zone. The results of this study will be useful as a basic material to establish development strategies and customized regional policy development, as well as balanced development.

• Journal of the Korean association of regional geographers
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• v.21 no.1
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• pp.39-61
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• 2015

This paper reviews literature on urban connectivity, and reconsiders the concept of polycentric urban region and its analysis methods, and then, applying them, explores the inter-city flight connectivity and polycentricity in the Yeongnam Region. As results of analysis, it has been identified that the entropy index shows a relatively dispersing pattern of the urban network of the region, and that the dominance index reveals a more polycentric (that is, less hierarchic) character of the region than that of the Capital Region, while some differences are found among individual cities in the symmetry of connectivity and the dominance and/or dependence index. Even though flows of products in textile, basic metals, and automobile industries in sub-divisions of manufacture appear a pattern of concentring into the first central city, the urban network of the Yeongnam Region in general can be characterized as a polycentrism, and policy for polycentric regional development would be suggested.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.123-130
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• 2017

The district heating system has been successfully implemented with higher efficiency levels of energy production and reduction of carbon emissions during heat generation. Traditionally the system consisted of small number of production and demand sites, but, recently it has evolved into a network with large number of sites interconnected each other. By connecting multiple sites into a network, heat from low-cost production sites can be supplied to distant demand sites so as to lower the total operation cost. In this study, we simulate and analyze distict heating networks focused on critical links. a critical link is defined as a link in which capacity is fully utilized. If a newtork has critical links, then those cricial links become bottlenecks and it is difficult to improve the overall network efficiency.

• Journal of Korea Water Resources Association
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• v.44 no.12
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• pp.1001-1013
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• 2011

Development of an optimal water supply system considering water quantity, quality, and economical efficiency is needed to decide optimal available area by combine water supply systems in overlapped area where are more than 2 water sources. The EPAnet and the KModSim were coupled to develop optimal network model. The developed network model was calibrated by measured data from water supply system in Geoje City, Korea in 2007 which have three water sources such as Sadeong booster pumping station, Guchun dam reservoir and Yoncho dam reservoir. The optimum network model was validated by operating results of 2011 to assess the economically optimized service area and optimal pump combination under the given hydraulic operating rules developed in this study. The developed model can be applied into designing water supply systems and operating rules for the conjunctive operation since the model can give the optimal solution satisfied with water quantity, economical efficiency and quality.