• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.2
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• pp.53-64
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• 2018

This study aims to quantitatively evaluate the conservation priorities of unexecuted urban parks in Seoul both from an ecological and public perspective. To this end, two methodologies, ecological network analysis based on graph and circuit theory and accessibility analysis, were employed in order to assess ecological connectivity of and public accessibility to unexecuted parks, respectively. This study applied linkage-mapping methods (shortest path and current flow betweenness centrality) of connectivity analysis to an integrated map of landscape permeability. The population-weighted accessibility to unexecuted parks was measured based on a negative exponential distance decay function. As a result, for both ecological connectivity and accessibility, Gwanaksan, Suraksan, and Bulamsan urban natural parks are found to be the most important (rank 1-3) to be conserved. For these sites, inner park areas with conservation priorities for connectivity and accessibility were identified. The findings of the study can be used for giving conservation priority to the unexecuted urban parks in terms of long-term sustainable urban planning.

• Spatial Information Research
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• v.20 no.5
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• pp.77-89
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• 2012

Walking is the most basic personal mobility and its importance and concern is ever increasing with the highlighting of a new paradigm, such as transit oriented development, sustainable development and revitalization of green transport. The existing analytical research on pedestrian network is using a pedestrian's moving distance to a destination and integration in space syntax theory as its representative accessibility factors. However, the uniplanar network moving distance fails to reflect topographic characteristics, so the moving distance could show a similar result value in case of the regions for analysis that have a similar network structure to each other. Accordingly, the aim of this study is to suggest a new analytical methodology on pedestrian network accessibility in consideration of the grade in pedestrian sections and a pedestrian's size. this study, in its analysis of a uniplanar pedestrian network moving distance, analyzed the pedestrian network moving distance in consideration of the grade in pedestrian sections, and even the pedestrian network moving distance in consideration of a pedestrian's size, and suggested the methodology on pedestrian network accessibility analysis in consideration of a more substantive pedestrian's characteristics. It is hoped that the methodology used by this study will be used as the methodology on pedestrian network analysis which can reflect topographic characteristics in the pedestrian network analysis, and take a more substantive pedestrian's movement into account.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.4
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• pp.335-349
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• 2018

This study analyzes the effect of the changes in traffic environments such as transportation speeds on the time-distance accessibility for the public transportation passengers. To do this, we use passenger transaction databases of the Seoul metropolitan public transportation system: one week for each of the three years (2011, 2013, and 2015). These big data contain the information about time and space on the traffic trajectories of every passenger. In this study, the time-distances of links between subway stations and bus stops of the public transportation system at each time are calculated based on the actual travel time extracted from the traffic-card transaction database. The changes in the time-distance accessibility of the integrated transportation network from the experimental results can be summarized in two aspects. First, the accessibility tends to decline as the year goes by. This is because the transportation network becomes more complicated and then the average moving speed of the vehicles is lowered. Second, the accessibility tends to increase on the weekend in the analysis of accessibility changes by day. This tendency is because the bus speeds on bus routes on the weekend are faster than other days. In order to analyze the accessibility changes, we illustrate graphs of the vehicle speeds and the numbers of passengers by year and day.

• Journal of Korea Spatial Information System Society
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• v.9 no.3
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• pp.25-33
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• 2007

The local governments of major cities in Korea are giving focus on public transportation to reduce congestion and improve accessibility in city areas. In this regards, the proper measurement of accessibility is now a key policy requirement for reorganizing the public transport network. Public transport routing problems, however, are considered to be highly complicated since a multi-mode travel generates different combinations of accessibility. While most of the previous research efforts on measuring transport accessibility are found at zone-levels, an alternative approach at a finer scale such as bus links and stops is presented in this study. We proposes a method to compute the optimal route choice of origin-destination pairs and measure the accessibility of the chosen modes combination based on topological configuration. The genetic algorithm is used for the computation of the journey paths, whereas the space syntax theory is used for the accessibility. This study used node-link data in GIS instead of axial lines which are manually drawn in space syntax. The resulting accessibilities of bus stops are calibrated by O-D survey data and the proposed process is tested on a CBD of Seoul.

• Health Policy and Management
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• v.27 no.4
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• pp.315-323
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• 2017

Background: This study was purposed to analyze the effect of spatial accessibility to the psychiatry department in general hospital on the outpatient visit of mental patients. Methods: Data was provided from the Statistics Korea and Statistical Geographic Information Service, National Health Insurance Service, Health Insurance Review and Assessment Service, and Korea Transport Institute in 2015. The study regions were 103 administrative regions such as Si and Gu. The 103 regions had at least one general hospitals with a psychiatry department. The number of outpatient visit of mental patients in regions was used as the dependent variable. Spatial accessibility to mental general hospital was used as the independent variable. Control variables included such as demographic, economic, and health medical factors. This study used network analysis and multi-variate regression analysis. Network analysis by ArcGIS ver. 10.0 (ESRI, Redlands, CA, USA) was used to evaluate the average travel time and travel distance in Korea. Multi-variate regression analysis was conducted by SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA). Results: Travel distance and time had significant effects on the number of outpatient visits in mental patients in general hospital. Average travel time and travel distance had negative effects on the number of visits. Variables such as (number of total population, percentage of aged population over 65, and number of mental general hospital) had significant effects on the number of visit in mental patients. Conclusion: Health policy makers will need to consider the spatial accessibility to the mental healthcare organization in conducting regional health planning.

• The Korean Journal of Health Service Management
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• v.13 no.1
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• pp.15-30
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• 2019

Objectives: This study aimed to analyze people's accessibility to medical institutions providing national gastric cancer screening services in Gangwon-do using a geographic information system(GIS). Methods: To assess the spatial accessibility, network analysis was applied. Two types of network analysis-Service area analysis and origin-destination cost matrix(OD-cost matrix)-were applied to create network dataset. Results: The results of the analysis of the service area revealed that it took more than 60 minutes each to reach tertiary hospitals and general hospitals from 74.4% and 9.6% of Gangwon-do areas, respectively. Similarly, it took more than 60 minutes each to reach hospitals and clinics from 4.2% and 3.4% of Gangwon-do areas, respectively. The results of the OD-cost revealed that there were large regional variations in distance and time taken to reach the medical institutions. Conclusions: there were regional variations of spatial accessibility between Si and Gun in Gangwon-do.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.4
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• pp.539-555
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• 2015

This study proposes the methodology for measuring the time-distance accessibility on the Seoul bus system based on the T-card transaction databases and analyzes the results. T-card transaction databases contain the time/space information of each passenger's locations and times of the departure, transfers, and destination. We introduce the bus network graph and develop the algorithms for time-distance accessibility measurement. We account the average speed based on each passenger's get-in and getoff information in the T-card data as well as the average transfer time from the trip chain transactions. Employing the modified Floyd APSP algorithm, the shortest time distance between each pair of bus stops has been accounted. The graph-theoretic nodal accessibility has been given by the sum of the inverse time distance to all other nodes on the network. The results and spatial patterns are analyzed. This study is the first attempt to measure the time-distance accessibility for such a large transport network as the Seoul bus system consists of 34,934 bus stops on the 600 bus routes, and each bus route can have different properties in terms of speed limit, number of lanes, and traffic signal systems, and thus has great significance in the accessibility measurement studies.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1715-1720
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• 2011

Studies suggested an increase in the competitiveness and roles of mainline railways like speed and accessibility improvement, as a fundamental direction of the National Transport Network Plan. At this point, topics presented especially for strengthening the role of human and environment centered transportation: as to the greatly improved speed competitiveness, there are an operational speed above 180km/h ~ 200km/h and traveling within 2 ~ 3 hours among big cities. As to accessibility improvement, there are accessibility to main railway stations within 30 minutes, and the improvement of accessibility, safety, eco-friendliness, amenity etc. As a part of these suggestions, field specific plans were proposed for the establishment of expressed mainline railway network in Korea such as train's, civil structures, trolley lines etc. In this paper we analyzed the conventional lines and systems to figure out whether to change details in terms of H/W of signaling system. Additionally, we reviewed the compatibility or difference of signalling system depending on train's speed. With this result, we deduced the number of virtual blocks specific to the speed of 180km/h, 200km/h and 230km/h, which were showed for the speed improvement considering each variable like blocks, braking distance etc. In this way, we suggested the railway signal system establishment plan considering safety operation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2150-2156
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• 2010

We focus on the network itself and its ability to enable efficient and effective information flow. All networks are complex to a greater degree, including military command and control systems operating in a network-centric environment. It requires to understand the nature of complexity, what its effects are, and how to quantify them. In this paper, we present the beneficial effects of information accessibility and network-based redundancy into a single metric.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.4
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• pp.513-525
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• 2019

In Seoul, the subway system has been in use since 1974 and is the most frequently used travel mode accounting for approximately 40% of passenger journeys in 2015. As such the subway system is widely adopted by people and therefore, can have great impacts on their everyday life. However, it is easily noted that transit resources are not distributed spatially uniform, in other words, not all parts of the city gain the same benefits from their networks. This study aims to examine the inequity of spatial distribution of subway networks based on accessibility. Accessibility of subway networks are calculated based on the time-distance between stations and then equity is measured using the Gini index. Resulted map of subway accessibility shows that the benefits are not evenly distributed in Seoul with a pattern of highly accessible core - less accessible periphery areas. Also the subway accessibility network has fairer distribution against the employees' distribution rather than the distribution of general population or possibly transit dependent groups.