• 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 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 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.

• Information and Communications Magazine
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• v.33 no.3
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• pp.46-52
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• 2016

통합공공용 주파수로 분배된LTE(Long Term Evolution) 718~728Mhz(상향) 및 773~783MHz(하향)에서 재난안전 통신망, 철도무선 통신망, 차세대 해상무선 통신망 등과 같은 LTE기반의 공공통신망(Public Network, 이하 공공망)이 상호 공존하여 사용하는 방안에 대하여 연구하였다. 두 개 이상의 복수의 LTE 네트워크가 동일 주파수를 사용하여 서비스하는 경우 통신 커버리지가 겹치는 영역에서의 간섭은 불가피하다. 셀 간 간섭에 의하여Mission Critical한 요구사항이 중요시되는 공공망에서의 품질 열화가 야기되며, 경우에 따라 심각한 상황을 초래할 수 있다. 본고에서는 국내 공공망의 현황을 살펴보고 네트워크 공유방식에 대한 기술 및 표준화 동향, 그리고 해외의 사례를 알아보았다. 국내 통합공공용 주파수에서 동일 주파수를 사용하게 될 공공망 간의 간섭을 최소화 하여 네트워크를 구축 및 연계를 위해서 개별 공공망간의 네트워크를 공유하는 방안을 고려하였다. 국내 공공망의 효율적인 네트워크 연계를 위해서는 개별 공공망의 서비스 특성과 내부 환경을 반영 할 수 있는 연계 방식이 추가적으로 필요하다.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.269-283
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• 2023

Based on daily data from January 4, 2016 to September 27, 2022, the impact of extreme movements of BDI on shipping companies' network connectivity was analyzed using CoVaR network connectivity. The main results and policy implications are as follows. First, according to the copula model results, the Student-t copula was selected as the most suitable model for COSCO, HMM, HRAG, MAERSK, and WAN. EVER was selected as a time-varying Gumbel copula, and YANG was selected as a time-varying rotated-Gumbel copula. Second, as a result of analysis using the TVP-VAR model, the linkage between shipping companies tended to increase when the BDI turned into an extreme risk state. In the comparison of net connectivity, the roles of COSCO and EVER changed. In addition, in the analysis of net pairwise connectivity, it was found that the change in the extreme risk state of BDI also affected the connectivity of shipping companies. In particular, EVER, WAN, and COSCO showed large changes. Taken together, the extreme fluctuations in BDI changed the role of Asian shipping companies, intensifying competition among shipping companies and strengthening risk delivery. It was confirmed that BDI has a great influence on the network connectivity of shipping companies and has an important influence on the stability of the stock market network. Therefore, the results of this study should consider not only the connectivity of shipping companies according to market conditions, but also the connectivity in extreme situations.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.823-826
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• 2008

This paper shows linkage management for external services. There are many services for specific entities such as DBLP and OntoWorld. OntoFrame, as a Semantic Web-based research information service portal, aims at one-stop service in ways that it connects external services with hyperlinks. For managing the linkage, linkage rules are manually edited by human administrators and automatically verified and tested by linkage management system. It consists of linkage rule management, linkage rule verification, linkage test, and dynamic link generation. Linkage rule management creates and edits linkage rules to connect external services on the Web. After finished rule editing and verification step, linkage management invokes linkage test with entity list. Only valid links are visible to enable users to click on our system, and thus it increases user's reliability on the system.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.177-179
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• 2003

기존 자연녹지인 앞산, 금호강/낙동강, 와룡산과 대상지내 산재해 있는 공원녹지를 연결하여 환상형(環狀形)의 그린네트워크를 형성하였다. 그린네트워크 조성에 따른 기존 자연녹지와 공원녹지 사이의 연계 방안으로 도시내 오픈스페이스인 학교용지를 선택하고 이를 연결하는 방안을 제시하였다 공원녹지의 위치상 1면이상이 도로와 접하고 있어 이를 연계하기 위한 가로공간의 녹화를 추진하여 녹지축을 연결하는 방안을 제시하였다. 또한, 도시내 자연녹지 중 도시하천의 역할을 분석하여 본 결과, 대상지내 그린네트워크를 조성하기 위해서는 하천변을 녹화하는 계획을 추진하여야할 것으로 사료된다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.275-277
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• 2018

친수 네트워크 개발은 기존 어촌지역 자원과 연계한 새로운 어촌체험콘텐츠 및 주민문화복지프로그램을 개발할 수 있는 의의를 가진다. 본 연구에서는 경남 어촌체험마을방문객 증가에 대응하고, 어민들 삶의 질을 향상 시킬 수 있는 어촌지역의 친수 네트워크 개발 방안을 연구하였다.

• 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.