• Title/Summary/Keyword: Functional connectivity network

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Theory of Network city and perspective on development of the Yeongnam region (네트워크도시 이론과 영남권 지역의 발전 전망)

  • Choi, Byung-Doo
    • 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.

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Cocaine-induced Changes in Functional Connectivities between Simultaneously Recorded Single Neurons in the SI Cortex and the VPL Thalamus of Conscious Rats

  • Shin, Hyung-Cheul;Park, Hyoung-Jin;Oh, Yang-Seok;Chapin, John K.
    • The Korean Journal of Physiology
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    • v.27 no.1
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    • pp.79-91
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    • 1993
  • The present study was carried out to determine the effects of cocaine (0.25, 1.0, 10.0 mg/kg, i.p.) on the interactions between spontaneously active neurons within ensembles of simultaneously recorded neurons in the primary somatosensory cortex (Sl, n= 20) and the ventroposterolateral (VPL, n= 16) thalamic nucleus of awake rats. Spike triggered cross correlation histograms were constructed between pairs of simultaneously recorded neurons. Among 101 neuronal pairs analyzed, 22.7% showed correlations indicative of various functional connections among the cortical cells, two corticothalamic interactions and one thalamocortical excitatory interaction. There were also 15 cofiring activities among SI cortical cells. These functional connectivities appeared to be modulated (weakened, abolished, or strengthened) during the 5 to 30 min following cocaine injection. The effects of saline were tested as a control, but it did not appear to alter the functional connectivities. In general, cocaine-induced changes of the functional interactions were mainly due to the concomitant alterations of the uncorrelated background discharges. These results suggest that the biphasic effects of cocaine on the spontaneously established neural networks among the SI cortical and the VPL thalamic cells of conscious rat were mainly indirect. However, various changes of the functional interactions by different doses of cocaine appeared to be a possible neural network mechanism for the cocaine induced modulation of afferent somatosensory transmission.

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Determination of Emergency Evacuation Roads Considering Road Network Function and Connectivity (도로네트워크 기능 및 연결성을 고려한 긴급대피교통로 선정)

  • Noh, Yunseung;Do, Myungsik
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.13 no.6
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    • pp.34-42
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    • 2014
  • This study is a fundamental research to determine the emergency evacuation roads considering road network function and connectivity. First of all, the functional aspects of the road networks are analyzed in the target area, Sejong city, by using degree centrality(DC) and closeness centrality(CC) from GIS based database. Secondly, how network connectivity makes a change in user's travel pattern and travel time and how it affects the whole network are analyzed using TransCAD simulation program. Finally, after performing cluster analysis of index, first and second emergency evacuation roads are determined by judging the characteristics of clusters. The results of this research will be helpful for making a decision to diminish secondary damages when confronting unexpected disasters.

Corridor and Network Analyses of Forest Bird Habitats in a Metropolitan Area of South Korea (수도권 지역 산림성 조류 서식지의 통로와 연결망 분석)

  • Kang, Wanmo;Park, Chan-Ryul
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.17 no.3
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    • pp.191-201
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    • 2015
  • Measuring and mapping connectivity among habitats is a key component of sustainable urban planning and design process. In this study, we examined how functional corridors connect forest bird habitats in a metropolitan area of Korea using graph theory-based techniques. High-quality forest habitat was defined as a function of forest cover, presence of residential areas, and road networks. We then constructed a network of high-quality forest habitats using the FunConn (functional connectivity) tools, and computed metrics ($T_i$) of patch importance based on the minimum ($Q_1$) and the 25th percentile ($Q_{25}$) rank least-cost distance values. We investigated the relative influence of two values of patch importance on forest bird species richness. As a result, the patch importance index based on the $Q_{25}$ effective distance threshold was most positively correlated with species richness (P < 0.001) after controlling for the area effect. Thus, using the $Q_{25}$ effective distance threshold, we mapped not only the locations of important habitat patches and functional corridors, but also the network backbone of forest bird habitats. The network developed in this study can help guide urban planning for biodiversity conservation.

Interactivity within large-scale brain network recruited for retrieval of temporally organized events (시간적 일화기억인출에 관여하는 뇌기능연결성 연구)

  • Nah, Yoonjin;Lee, Jonghyun;Han, Sanghoon
    • Korean Journal of Cognitive Science
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    • v.29 no.3
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    • pp.161-192
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    • 2018
  • Retrieving temporal information of encoded events is one of the core control processes in episodic memory. Despite much prior neuroimaging research on episodic retrieval, little is known about how large-scale connectivity patterns are involved in the retrieval of sequentially organized episodes. Task-related functional connectivity multivariate pattern analysis was used to distinguish the different sequential retrieval. In this study, participants performed temporal episodic memory tasks in which they were required to retrieve the encoded items in either the forward or backward direction. While separately parsed local networks did not yield substantial efficiency in classification performance, the large-scale patterns of interactivity across the cortical and sub-cortical brain regions implicated in both the cognitive control of memory and goal-directed cognitive processes encompassing lateral and medial prefrontal regions, inferior parietal lobules, middle temporal gyrus, and caudate yielded high discriminative power in classification of temporal retrieval processes. These findings demonstrate that mnemonic control processes across cortical and subcortical regions are recruited to re-experience temporally-linked series of memoranda in episodic memory and are mirrored in the qualitatively distinct global network patterns of functional connectivity.

Analysis of Wildlife Moving Route with Landscape Characteristics (경관의 특성에 따른 동물의 이동경로에 관한 연구)

  • Lee, Dong-Kun;Park, Chan;Song, Won-Kyong
    • Journal of Environmental Impact Assessment
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    • v.17 no.2
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    • pp.133-141
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    • 2008
  • The loss, alteration, and fragmentation of habitat have led to a reduction of biodiversity. The growing awareness of the negative effects of habitat fragmentation on natural systems has resulted in conservation strategy that is concerned with not only population and habitat level but also ecosystem and landscape level. Especially, ecological network to link core areas or major habitat patches is one of the most important issues. Recently, landscape connectivity is increasingly used in decision making for fragmented landscape management in order to conserve the biodiversity in the regional scale. The objective of this study was to find potential forest as a ecological corridor in Go-yang city, Gyung-gi province using cost-distance modelling method that can measure connectivity based on animal movement. 'Least cost-distance' modelling based on functional connectivity can be useful to establish ecological network and biodiversity conservation plan. This method calculates the distance modified with the cost to move between habitat patches based on detailed geographical information on the landscape as well as behavioural aspects of the animal movement. The least cost-distance models are based on two biologically assumptions: (1) dispersers have complete knowledge of their surroundings, and (2) they do select the least cost route from this information. As a result of this study, we can find wildlife moving route for biodiversity conservation. The result is very useful for long-term aspect of biodiversity conservation plan in regional scale, because this is reflection of geographical information and behavioural aspects of the animal movement.

Evaluating the Criteria and Weight Value for Ecological Network Connectivity of Baekdudaegan Mountain Range on Taebaeksan National Park (태백산국립공원 백두대간 생태축 연결을 위한 평가항목 및 가중치 설정)

  • Shin, Geehoon;Kim, Hye-Ri;Jang, Su-Rim;Kim, Hak-Yoon;Rho, Paikho
    • Korean Journal of Environment and Ecology
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    • v.33 no.3
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    • pp.292-302
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    • 2019
  • This study conducted a hierarchy analysis based on a questionnaire survey of experts in park management, ecosystem survey, and ecological environment planning to establish evaluation items and a weighing value of each item to develop ecological connectivity in Baekdudaegan mountain range neighboring the Taebaeksan National Park using the AHP approach. We selected four high-level evaluation indexes and 13 low-level evaluation indexes through literature review and interview with the people in the field and calculated weights for each question through the consistency analysis. The analysis showed that increasing the ecological value was the most important item with the index of 0.474 among the high-level evaluation items, followed by the mitigation of human-nature conflict at 0.247, participation by local residents at 0.165, and the economic perspective at 0.114. Among the low-level evaluation indexes, the movement route of wildlife was the highest at 0.116, followed by the connectivity of landscape ecological patch at 0.112, and functional habitat at 0.099. The comparison of the evaluation items in each working group and the weight factors showed that the movement route of wildlife was the most important at 0.116 in ecosystem survey, the functional habitat was the most important at 0.110 in park management, and the regional preservation and distribution of resources was the most important at 0.123 in ecological environment planning. The results of this study is useful to identify evaluation items for developing ecological network with a diverse source of the actual environmental data in the Taebaeksan National Park.

The Roles of Frontal Cortex in Primary Insomnia : Findings from Functional Magnetic Resonance Imaging Studies (일차성 불면증에서 전두엽의 역할 : 기능적 자기공명영상 연구)

  • Kim, Bori;Park, Su Hyun;Cho, Han Byul;Kim, Jungyoon
    • Korean Journal of Biological Psychiatry
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    • v.25 no.1
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    • pp.1-8
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    • 2018
  • Insomnia is a common sleep-related symptom which occurs in many populations, however, the neural mechanism underlying insomnia is not yet known. The hyperarousal model explains the neural mechanism of insomnia to some extent, and the frontal cortex dysfunction has been known to be related to primary insomnia. In this review, we discuss studies that applied resting state and/or task-related functional magnetic resonance imaging to demonstrate the deficits/dysfunctions of functional activation and network in primary insomnia. Empirical evidence of the hyperarousal model and proposed relation between the frontal cortex and other brain regions in primary insomnia are examined. Reviewing these studies could provide critical insights regarding the pathophysiology, brain network and cerebral activation in insomnia and the development of novel methodologies for the diagnosis and treatment of insomnia.

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Brain Connectivity Analysis using 18F-FDG-PET and 11C-PIB-PET Images of Normal Aging and Mild Cognitive Impairment Participants (정상 노화군과 경도인지장애 환자군의 18F-FDG-PET과 11C-PIB-PET 영상을 이용한 뇌 연결망 분석)

  • Son, S.J.;Park, H.
    • Journal of Biomedical Engineering Research
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    • v.35 no.3
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    • pp.68-74
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    • 2014
  • Recent research on mild cognitive impairment (MCI) has shown that cognitive and memory decline in this disease is accompanied by disruptive changes in the brain functional network. However, there have been no graph-theoretical studies using $^{11}C$-PIB PET data of the Alzheimer's Disease or mild cognitive impairment. In this study, we acquired $^{18}F$-FDG PET and $^{11}C$-PIB PET images of twenty-four normal aging control participants and thirty individuals with MCI from ADNI (Alzheimer's Disease Neuroimaging Initiative) database. Brain networks were constructed by thresholding binary correlation matrices using graph theoretical approaches. Both normal control and MCI group showed small-world property in $^{11}C$-PIB PET images as well as $^{18}F$-FDG PET images. $^{11}C$-PIB PET images showed significant difference between NC (normal control) and MCI over large range of sparsity values. This result will enable us to further analyze the brain using established graph-theoretical approaches for $^{11}C$-PIB PET images.

Design of In-situ Self-diagnosable Smart Controller for Integrated Algae Monitoring System

  • Lee, Sung Hwa;Mariappan, Vinayagam;Won, Dong Chan;Shin, Jaekwon;Yang, Seungyoun
    • International Journal of Advanced Culture Technology
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    • v.5 no.1
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    • pp.64-69
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    • 2017
  • The rapid growth of algae occurs can induce the algae bloom when nutrients are supplied from anthropogenic sources such as fertilizer, animal waste or sewage in runoff the water currents or upwelling naturally. The algae blooms creates the human health problem in the environment as well as in the water resource managers including hypoxic dead zones and harmful toxins and pose challenges to water treatment systems. The algal blooms in the source water in water treatment systems affects the drinking water taste & odor while clogging or damaging filtration systems and putting a strain on the systems designed to remove algal toxins from the source water. This paper propose the emerging In-Situ self-diagnosable smart algae sensing device with wireless connectivity for smart remote monitoring and control. In this research, we developed the In-Site Algae diagnosable sensing device with wireless sensor network (WSN) connectivity with Optical Biological Sensor and environmental sensor to monitor the water treatment systems. The proposed system emulated in real-time on the water treatment plant and functional evaluation parameters are presented as part of the conceptual proof to the proposed research.