• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.6 s.107
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• pp.14-22
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• 2005

The purpose of this paper is to assess conservation value of forests and cultivated areas from the landscape ecological point of view. The main focus of landscape ecology estimates the reciprocal relationships between spatial patterns and ecological processes. This paper sets the criteria for conservation value and classify the conservation value based on the criteria. Forests and cultivated areas in Seo-Gu, Incheon Metropolitan City was selected as the case study area. In this research, factors such as patch size and connectivity have been selected in order to consider the landscape ecological aspect, gradient for the environmental physics aspect and to consider the environment-ecological aspect, grade of environmental-oriented land suitability analysis Map developed by the ROK Ministry of Environment has been utilized. GIS methodologies have been adopted to calculate the relationships among the above variables. Through literature review, the following evaluation criteria have been adopted: (1) based on island biogeography and metapopulation dynamics theory, patch size criteria are set 2ha and 10ha; (2) connectivity was set the degree of connection with surrounding grids; and (3) gradient of 20 degrees. Conclusively, this paper suggests that local conditions, landscape ecology and physical environment aspects should be considered to develop an estimation framework of the conservation value.

• Korean Journal of Biological Psychiatry
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• v.24 no.2
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• pp.68-74
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• 2017

Objectives It is well known that problem drinking is associated with alterations of brain structures and functions. Brain functions related to alcohol consumption can be determined by the resting state functional connectivity in various resting state networks (RSNs). This study aims to ascertain the alcohol effect on the structures forming predetermined RSNs by assessing their cortical thickness. Methods Twenty-six abstinent male patients with alcohol dependence and the same number of age-matched healthy control were recruited from an inpatient mental hospital and community. All participants underwent a 3T MRI scan. Averaged cortical thickness of areas constituting 7 RSNs were determined by using FreeSurfer with Yeo atlas derived from cortical parcellation estimated by intrinsic functional connectivity. Results There were significant group differences of mean cortical thicknesses (Cohen's d, corrected p) in ventral attention (1.01, < 0.01), dorsal attention (0.93, 0.01), somatomotor (0.90, 0.01), and visual (0.88, 0.02) networks. We could not find significant group differences in the default mode network. There were also significant group differences of gray matter volumes corrected by head size across the all networks. However, there were no group differences of surface area in each network. Conclusions There are differences in degree and pattern of structural recovery after abstinence across areas forming RSNs. Considering the previous observation that group differences of functional connectivity were significant only in networks related to task-positive networks such as dorsal attention and cognitive control networks, we can explain recovery pattern of cognition and emotion related to the default mode network and the mechanisms for craving and relapse associated with task-positive networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1256-1275
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• 2014

As one of the new self-organizing and self-configuration broadband networks, wireless mesh networks are being increasingly attractive. In order to solve the load balancing problem in wireless mesh networks, this paper proposes a novel multi-path routing algorithm based on clustering (Cluster_MMesh) for wireless mesh networks. In the clustering stage, on the basis of the maximum connectivity clustering algorithm and k-hop clustering algorithm, according to the idea of maximum connectivity, a new concept of node connectivity degree is proposed in this paper, which can make the selection of cluster head more simple and reasonable. While clustering, the node which has less expected load in the candidate border gateway node set will be selected as the border gateway node. In the multi-path routing establishment stage, we use the intra-clustering multi-path routing algorithm and inter-clustering multi-path routing algorithm to establish multi-path routing from the source node to the destination node. At last, in the traffic allocation stage, we will use the virtual disjoint multi-path model (Vdmp) to allocate the network traffic. Simulation results show that the Cluster_MMesh routing algorithm can help increase the packet delivery rate, reduce the average end to end delay, and improve the network performance.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.412-420
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• 2011

This study was conducted to quantitatively analyze the temporal change of green space network at multi-scales from 1975 to 2006 with the application of graph theory in Seoul, Korea. Remarkable change of connectivity was detected in green space networks at the scale ranging from 1,000 ~ 1,600 m during 30 years. Green spaces and their networks have been restoring after 1990 since forest areas had been fragmented in 1975. In 2006, we identified the important core habitat areas that can sustain diverse wildlife species and stepping stones composed of small patches that can link these core habitat areas. Green spaces showed high correlation with the relative importance value of green space connectivity. So, this study could graphically represent green space networks of Seoul City. Green spaces of core areas distributed at the northern and southern boundary, and those of stepping stones possessing the high value of betweenness centrality consisted at the middle, eastern and western boundary. These results indicate that green space network can be graphically and quantitatively explained by degree centrality, betweenness centrality and relative importance value of connectivity with the application of graph theory.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.56-67
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• 2005

Rapid and reckless economical development is causing nationwide deforestation; more and more forest is being developed to be used as a base for economic advancement. While benefiting the national economy, this destruction of forest is creating a serious problem in the National Land Plan. To solve this problem, it is imperative to understand the current condition of damaged forest and make an environment-friendly plan. This paper explains the principles of spatial plan and sets the criteria for the plan, such as patch size, connectivity, and edge of the Landscape Ecology. The paper assesses the conservational value of area that are currently being developed or planned to be developed to figure out the current environmental situation. This conservational value was verified by the field survey. The result of assessment appears that the patch size of the major mountains in site is over 1,000ha and edge is located widely beside roads. The area of the high connectivity is located agriculture area in valley or narrow roads. The research shows that the patch size is related to biodiversity the larger the patch size, the more populated the species are. The research also reveals the conservational value indicated by degree of connection to forest, difference in the structure of vegetation between core area and edge area, and effects of surrounding environment. In further study, we will assess other criteria of conservation value, such as patch shape and fragmentation to the Landscape Ecology, and apply those criteria in biological aspects of the spatial plan.

• Journal of the Korea Society for Simulation
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• v.27 no.4
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• pp.9-18
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• 2018

This paper proposes new algorithms of accessibility indices to analyze the connectivity of the Korean highway network. First of all, we find a transportation network that presents Korea's highway network in graphs in 2011 and 2017. And we analyze and compare the nation's highway network in 2011 and 2017 using concepts such as associated number, the relative distance, the accessibility, the degree of connectivity, the index of dispersion, the diameter of graph theory. To do this, an algorithm is presented which can easily obtain various accessibility indices from a given transportation network. Using the simulation results of this study, we can find city that is the center of traffic in the highway transportation network. In addition, cities that are included in the network but are relatively underdeveloped can be found and used as basic data for enhancing the connectivity of the nationwide traffic in the future. Moreover, the proposed algorithms of accessibility indices, which are modeled on highway transport networks, can help identify the accessibility space structure of each city and provide criteria for efficient and reasonable selection of alternatives in various regional planning processes, including transportation.

• The Journal of Engineering Geology
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• v.24 no.2
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• pp.179-189
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• 2014

We analyzed the three-dimensional distribution of micropores and internal structures in both fresh and weathered granite using micro-focus X-ray computed tomography (micro-CT). Results show that the pore radius in fresh granite is mostly in the range of $17-50{\mu}m$, the throat radius is in the range of $5-25{\mu}m$, and the coordination number (CN) of pores is less than 10. In contrast, the pore radius in weathered granite is mostly in the range of $20-80{\mu}m$, the throat radius is in the range of $8-30{\mu}m$, and the CN is less than 12. In general, a positive linear relationship exists between pore radius and CN. In addition, both the size and the density of pores increase with an increasing degree of rock weathering. The size of the throats that connect the pores also increases with an increasing degree of weathering, which induces fracture propagation in rocks. Micro-CT is a powerful and versatile approach for investigating the three-dimensional distributions of pores and fracture structures in rocks, and for quantitatively assessing the degree of pore connectivity.

• Journal of Korea Port Economic Association
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• v.39 no.2
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• pp.15-23
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• 2023

In a situation where the necessity and importance of ESG management is increasing recently, it is judged that selecting important ESG-related variables for container terminals, which are the bases of export and import logistics, among various variables of ESG evaluation agencies will help to establish ESG management strategies for container terminals which led us to proceed with this study. The results of word network analysis are summarized as follows. The weighed degree, that is, the AWD of Environmental management(E) variables, is obtained in the order of Environmental Protection Investment(54), Environmental Awareness Education(45), Work Team Structure(31), Environmental certification(32). Page Ranks, the order of centrality and connectivity index is Environmental Awareness Education(0.0765), Employee Engagement(0.0765), Environmental Protection Investment(0.0761), Work Team Composition(0.0761), and Environmental certification(0.0761). The AWD(Average Weighed Degree) of the Social Responsibility Management(S) variables, followed by Protecting workers' human rights and contributing to local communities(68), Safety Education(63), Safety certification(59), and Responding to infectious diseases(40). Orders by Page Ranks, centrality and connectivity Index, are Protecting workers' human rights and contributing to local communities(0.165), Safety Education(0.153), Safety Certification(0.144) and Responding to infectious diseases(0.102). The AWD of Governance and Ethical management(G) variables, followed by Anti-corruption(27), Transparent management(24), Mutual cooperation between stakeholders(19), and Sustainability reporting(9). Page Ranks, the order of centrality and connectivity index is the Anti Corruption(0.241), Transparent management(0.216), Mutual cooperation between stakeholders(0.174), Directors' roles and responsibilities(0.105), Shareholder protection(0.097) and Sustainability Report(0.096).

• Journal of Korea Water Resources Association
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• v.47 no.4
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• pp.397-409
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• 2014

In this study, the assessment scheme has been developed to evaluate the ecological function of rivers which were changed by the river improvement project. The evaluating factors are composed of physical structure in river channels and ecological connectivity in river areas, and each value of the factors is quantified based on 4 and 2 variables, respectably. This scheme was applied to past (1918, before artificial river improvement) and present Mankyung River area. A GIS model was adopted for calculating, analysing, and presenting river ecological conditions using the 204 grids and 7 reaches in study area. Comparison results show that the evaluation grade was decreased in both factors after river improvement. The main causes of lower grade (from II to IV) for physical structure are the river straightening and crossing structures. The reduction (from II to III) in ecological connectivity grade effected by linear fragmentation due to roads and rails is found to be greater than areal fragmentation due to land-use. In particular, it is also found that a high degree of ecological connectivity in 1918 was distributed along the river, but that one in 2007 showed a tendency to scatter because of the construction of levee and increase of urbanized area.

• Journal of Navigation and Port Research
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• v.41 no.3
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• pp.155-164
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• 2017

While many countries are implementing various policies regarding the logistics network in Eurasia, China has presented "the Belt and Road" Initiative, a development strategy that focuses on connectivity and close cooperation between China and Eurasia. With more than 60 countries participating in the project, China is expected to have a major influence on logistical infrastructure development in Eurasia. This study analyzed the railway stations network using social network analysis (SNA) methodology. We collected data from major railway lines in Eurasia (TAR, TEN-T, TRACECA, GMS) and established a network of 994 railway stations in 65 countries. This study presented the general characteristics of major railway stations from the perspective of SNA and compared the Chinese network with Eurasian networks. To review the railway networks in China and Eurasia, the top 30 stations were selected based on degree centrality and betweenness centrality. Top "degree centrality" stations included Bangkok (Thailand), Tbilisi (Georgia), Baku (Azerbaijan), Kunming (China), and Bucharest (Romania). Top "betweenness centrality" stations were Baku and Alyat (Azerbaijan), Baoji and Turpan (China), Qarshi (Uzbekistan), and Kas (Turkey). In China, Kunming, Nanning, and Gejiu stations have higher degree centrality while betweenness centrality was higher in Baoji, Kunming, and Lanzhou stations. "The Belt and Road" project advocated by China envisions expansion of transportation infrastructure connections throughout Eurasia, but more emphasis is likely to be placed on connectivity that benefits China. In this regard, studies on key bases of international logistics need to consider relative significance within the Chinese network.