• Title/Summary/Keyword: network cities

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Developing Cyber-Compact City Strategies for Sustainable Transportation (지속가능교통을 위한 사이버 압축도시 개발 방안 연구)

  • Choo, Sang-Ho;Sung, Hyun-Gon
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.10 no.1
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    • pp.112-123
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    • 2011
  • This study focused on developing strategies of cyber-compact city, combining compact city with information and communications technologies(ICTs), in order to enhance sustainable transportation. The cyber-compact city development is defined as a development that is able to reduce travel by ICTs and encourage people to use transit or non-motorized vehicles such as bicycles for ICT-induced travel (especially, discretionary travel) by compact and mixed land use. It can be achieved with combining cyber and compact strategies with respect to network, node, and area. For example, ICT network may use transit network facility, a transfer station may be a hub of ICTs, and transit influenced zone may work with ICT service area. We proposed three cohesive strategies for the cyber-compact city based on literature review and case studies on cyber and compact cities. The first strategy is a cohesion between public transportation and telecommunication network by centering on the two for national and urban spatial linkage structure. That is, cities or urban centers and its peripheral areas can be connected by rail network, and extra space of railway network can be used for constructing telecommunication network infrastructure. The second strategy is a cohesion between public transportation node and telecommunication node by building up regional and urban telecommunication centers near to or at main railway stations. For this strategy, telework centers and communication service centers should be established mainly at transfer stations. The third strategy is a cohesion between public transportation impact zone and telecommunication impact zone as transit oriented development.

The Periodical Trend of Urban Regeneration through Mass Media - Focused on the 1920s and 1990s - (매스미디어를 통해 본 도시재생의 시대적 동향 - 1920년대~1990년대를 중심으로 -)

  • Kim, Sa-rang;Lee, Jeong
    • Journal of the Korean Institute of Landscape Architecture
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    • v.47 no.2
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    • pp.28-48
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    • 2019
  • This research is aimed at identifying the perception associated with urban regeneration and predicting policy implications of future directions by analyzing the trend of urban regeneration depicted in the mass media by utilizing SNA (Semantic-Network Analysis) techniques. As the number of articles has increased, it is noted through analysis that the interrelationships between social phenomena and issues have combined to form the meaning of urban regeneration. Overall, 'urban' and 'regeneration' keywords also appeared at different periods, with 'urban' closely related to 'regeneration' starting in 1970 when urbanization was becoming more prevalent. It was analyzed that the frequency of 'urban' appeared more frequently in the early 1990s, while the frequency of 'rural' decreased sharply. Until the 1990s, the slums and the recession that appeared as side effects of urban problem-solving policies were mostly concentrated in cities. Policy discussions were conducted with the goal of improving the physical environment of cities rather than concentrating on the surrounding rural areas. The distributions of the keywords 'development' and 'regeneration' have increased quantitatively since the 1970s, and urban polarization has exploded due to the development of the external growth of cities, mirroring the trend of accelerated environmental threats. In particular, the keywords for 'regeneration' emerged mainly related to environmental problems, which led to the need for urban regeneration, and environmentally and ecologically friendly development. The emergence of "urban," "regeneration" and "environment" as keywords having to do with urban regeneration grew in the 1990s. This suggests that urban regeneration is now linked to "environment", as that has become a social issue.

Voltage Stability Prediction on Power System Network via Enhanced Hybrid Particle Swarm Artificial Neural Network

  • Lim, Zi-Jie;Mustafa, Mohd Wazir;Jamian, Jasrul Jamani
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.877-887
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    • 2015
  • Rapid development of cities with constant increasing load and deregulation in electricity market had forced the transmission lines to operate near their threshold capacity and can easily lead to voltage instability and caused system breakdown. To prevent such catastrophe from happening, accurate readings of voltage stability condition is required so that preventive equipment and operators can execute security procedures to restore system condition to normal. This paper introduced Enhanced Hybrid Particle Swarm Optimization algorithm to estimate the voltage stability condition which utilized Fast Voltage Stability Index (FVSI) to indicate how far or close is the power system network to the collapse point when the reactive load in the system increases because reactive load gives the highest impact to the stability of the system as it varies. Particle Swarm Optimization (PSO) had been combined with the ANN to form the Enhanced Hybrid PSO-ANN (EHPSO-ANN) algorithm that worked accurately as a prediction algorithm. The proposed algorithm reduced serious local minima convergence of ANN but also maintaining the fast convergence speed of PSO. The results show that the hybrid algorithm has greater prediction accuracy than those comparing algorithms. High generalization ability was found in the proposed algorithm.

Isolated-Word Recognition Using Neural Network and Hidden Markov Model (Neural-HMM을 이용한 고립단어 인식)

  • 김연수;김창석
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.11
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    • pp.1199-1205
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    • 1992
  • In this paper, a Korean word recognition method which usese Neural Network and Hidden Markov Models(HMM) is proposed to improve a recognition rate with a small amount of learning data. The method reduces the fluctuation due to personal differences which is a problem to a HMM recognition system. In this method, effective recognizer is designed by the complement of each recognition result of the Hidden Markov Models(HMM) and Neural Network. In order to evaluate this model, word recognition experiment is carried out for 28 cities which is DDD area names uttered by two male and a female in twenties. As a result of testing HMM with 8 state, codeword is 64, the recognition rate 91[%], as a result of testing Neural network(NN) with 64 codeword the recognition rate is 89[%]. Finally, as a result of testing NN-HMM with 64 codeword which the best condition in former tests, the recognition rate is 95[%].

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Constructing a Green Network and Wind Corridor to Alleviate the Urban Heat-Island (도시열섬현상 완화를 위한 녹지네트워크 및 바람길 구축)

  • Cha, Jae-Gyu;Jung, Eung-Ho;Ryu, Ji-Won;Kim, Dae-Wuk
    • Journal of the Korean Association of Geographic Information Studies
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    • v.10 no.1
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    • pp.102-112
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    • 2007
  • Like other organic beings, modern cities change every day. Unlike in the past, changes of space which have been taking place in concentrated spaces during short periods of time have worsened the environment of cities creating environmental problems. In particular, the urban heat-island phenomenon, which is caused by changes in using the earth's surface, has emerged as a key social issue along with health problems and economic difficulties. The Green Network has been introduced as an urban planning approach to solve the urban heat-island phenomenon. This study suggests constructing a Green Network through analyzing the urban heat island phenomenon, land cover classification, and linkage possibility with the Green Network and wind corridors by researching Jung-Gu, and Nam-Gu in Daegu Metropolitan City. In conclusion, this study presented the construction of a broad and detailed Green Network of object areas by assigning Apsan to the southern area and mountain area as the core, two areas of Nam-Gu and six areas of Jung-Gu such as Duryu Park and, Dalsung Park as footholds and other school land and park facility areas as footholds-to-be areas. In particular, Camp Walker, which is connected with Apsan, is not only a foothold but connected to the core, is necessary to preserve after being transferred from the U.S. Army. In addition, assigning the Susung Bridge area of Jung-Gu and the Camp Walker area of Nam-Gu as the wind corridor areas is recommended.

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Street Transit Network Analysis and Evaluation (노면 대중교통노선 평가틀 구축에 관한 연구)

  • Shin, Yong Eun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.4D
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    • pp.477-483
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    • 2008
  • If designed properly, street transit systems can provide many useful functions with the flexibility of serving an unlimited range of locations throughout an urban area. Over the last decades urban regions of Korea cities have seen rapidly changing travel patterns and urban conditions. Under this circumstance transit planners need frequent evaluations of its street transit routes so as to restructure or modify them rationally. It should be noted that the changing network influences passengers, operators, as well as the city itself. However, there is no proper framework with which to evaluate the street transit network comprehensively. This paper develops and provides a framework including criteria and indicators for evaluating street transit networks. Five criteria, such as network size, network structure, service requirements, efficiency of operation and the relationship to the city are presented. A number of indicators and measures representing each criteria are then suggested. As a practical example, an analysis and comparison of three minibus networks in Busan are presented, utilizing the developed measures and indicators. The results of this study will be of great use for planners responsible for transit route planning, particularly for planning of new or analysis of existing routes; their comparison with routes/networks of various cities.

High speed rail-air links : some lessons from the French case (고속철도와 항공기의 연계체계 : 프랑스 사례와 시사점)

  • 이경철;문대섭;정병현
    • Proceedings of the KSR Conference
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    • 2002.05a
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    • pp.111-115
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    • 2002
  • The TGV has been developed in a competition with the domestic air transport. But recently, with congestion, do-regulation of air transport and with the increase of number of cities served by the TGV, operators of rail and air transport are looking for a complementarity between the two modes. In this paper, we'll analyse the background and development of high-speed rail-air links in France for a development plan of high speed transportation network in a national level in Korea.

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A Study on Data Inference using Machine Learning in WSN Environment (무선 센서 네트워크 환경에서 기계 학습을 이용한 데이터 추론에 관한 연구)

  • Jung, Yong-Jin;Cho, Kyoung-Woo;Oh, Chang-Heon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.05a
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    • pp.571-573
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    • 2018
  • The loss of data collected from the sensor node in the wireless sensor network environment is caused by the hidden node of the sensor node and power shortage. In order to solve these problems, researches have been actively carried out to maintain the network effectively, but there is no study on the situation where the maintenance of the network is impossible. Therefore, research is needed to infer lost data in situations where network maintenance is impossible. In this paper, use particulate matter data of specific cities to deduce lost data. Analyze the accumulated data through machine learning and identify the possibility of inferring lost data.

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Applying the Space Syntax Technique to the Network of Public Transportation (Space Syntax 기법의 대중교통망 적용 방안에 관한 연구)

  • Jun, Chul-Min
    • Journal of Korean Society for Geospatial Information Science
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    • v.12 no.2 s.29
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    • pp.73-77
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    • 2004
  • Due to the traffic congestion of the city and public transportation-oriented policies in large cities, public transportation is receiving attention and being used increasingly. However, relatively less research on the design and distribution of public transportation network and limitations in quantitative approaches have made implementation and operation practically difficult. Over- or under-supply of transportation routes caused unbalanced connectivity among areas and, thus, differences in time, expenses and metal burden of users traveling the same distances. On the other hand, the Space Syntax theory, originally designed to calculate the connectivity of urban or architectural spaces, helps generate quantitative connectivity of whole space simply based on the spacial structure. This study modified the original Space Syntax algorithm to fit the public transportation problem and showed how it is applied to a transportation network by creating an artificial GIS network.

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A Study on the Fault Current Characteristics for the Utility Application of HTS Power cable (초전도 전력케이블의 전력계통 적용을 위한 고장전류 특성에 관한 연구)

  • Kim, Jae-Ho;Park, Min-Won;Sim, Ki-Deok;Cho, Jeon-Wook;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.75-76
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    • 2007
  • Several kinds of High Temperature Superconducting(HTS) power cables have already been developed and evaluated for use in the utility power network. HTS power cable is expected to be used as a very powerful energy delivery system supplying electric power for densely populated cities in the near future, because HTS power cable is capable of the high current density delivery with low AC loss and the size effect comparing with the conventional cable whose capacity is same. Before applying the HTS power cable to real utility network system analysis should be carried out by some simulation tools. Hereby the electrical power system analysis is very important for the practical use of HTS power devices. In this paper, authors propose a real-time simulation method which incorporates a real HTS tapes into the simulated 22.9kV utility power network system using Real Time Digital Simulator(RTDS). For the simulation analysis, a test sample of HTS tapes was actually manufactured, and the transient phenomenon of HTS power cable system was analyzed in the simulated utility power network.

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