• Title/Summary/Keyword: Traffic density

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Changes in Demographic and Housing Characteristics of New Towns in Korea: Focused on Five New Towns in Seoul Metropolitan Area (우리나라 신도시의 인구 및 주거특성 변화: 분당, 일산 등 1기 신도시를 중심으로)

  • Yoon, Jeong-Joong;Kim, Eun-Mi
    • Land and Housing Review
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    • v.5 no.4
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    • pp.235-246
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    • 2014
  • In the late 1980s, 5 new towns such as Bundang, Ilsan, Pyeongchon, Sanborn, Jungdong were constructed to solve housing problems and to disperse functions concentrated within Seoul. As the city got matured, it began to appear the initial signs of urban problems such as aging of high rise-density apartment sites, traffic congestion, lack of parking spaces and aging of infrastructure. Therefore, in order to cope with urban problems, it is very important to apprehend the process of urban growth, its change and the feature of physical/human elements. So, the purpose of this thesis is to analyze the changes in housing and population characteristics for past 20 years by use of Census data from 1995 to 2010. First, the new town's goal of population and housing plan at the time of construction was analyzed how it was achieved, and it is close to the performance of the goal. And the trend of changes in the population and household characteristics was analyzed by every five year's data. As the result of analysis, it shows socio-demographic changes such as aged and elderly population growth, rapid increase in one generation's household and single person household, highly educated city, monthly rent household's increase and charter household's reduction. Results of this analysis can be utilized to aforethought management of new towns. But it is required more sustained and systematic urban monitoring and data analysis because the one-off analysis of the city's characteristics alone is difficult enough to grasp them.

An Experimental Study About a Net-Type External Prestress Strengthening Method for Slab Bridges (네트형 외부 긴장재에 의한 슬래브교 보강 실험)

  • Han, Man Yop;Kang, Tae Heon;Choi, Sok Hwan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.5
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    • pp.136-149
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    • 2011
  • Large portion of the domestic bridges are slab bridges reflecting the geographical characteristic of the country, where exists lots of inclines and small winding brooks. Many of the slab bridges are damaged and superannuated as they become obsolete. Deterioration is accelerated when the traffic density becomes large and heavy vehicles pass frequently. A strengthening method for deteriorated slab bridges was studied in this work. The examined net-type strengthening method uses both longitudinal and transverse prestressing for strengthening. In this way, the deflection at the center of the slab can be better controlled, and consequently, the slab is more efficiently strengthened. Three slab specimens were fabricated for the experimental test and subjected to three different loading conditions, and the load bearing capacities and deflections of slabs were examined. Flexural stiffness of slabs increased by 30.7~107.3%, and deflection of slabs decreased by 27.6~52.2% after net-type strengthening. The net-type prestressing is efficient to the strengthening for the center of a slab, and its efficiency is also valid under eccentric loadings. Since extra prestress forces can be added in the future, if necessary, the net-type strengthening system is advantagous for the maintenance and repair of slab bridges.

A Performance Analysis of an Adaptive Sector Cell System using the Measured Urban Wireless Channel Data (도심 무선채널의 실측데이터를 이용한 적응 섹터 셀 시스템의 성능분석)

  • Ko, Hak-Lim;Park, Byeong-Hoon;Lee, Jong-Heon
    • Journal of the Institute of Convergence Signal Processing
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    • v.9 no.1
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    • pp.24-30
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    • 2008
  • In this paper we analyze the performance of an adaptive sector cell system, which is adopted to maintain the traffic balance between sectors and to utilize the cell resources effectively, using the data collected from real channel environments. In the data measurements, we transmitted the QPSK modulated signal with carrier frequency of 1.95GHz and received the signals using the 8x4 array antenna equipped on the top of buildings in the urban area. We analyzed the angular distribution and the delay spread of a user signal and analyzed angular distribution of mobile users in a cell using the collected data. Also, we propose the vector channel modeling using the estimated pdf(probability distribution function) of the analyzing results. Through the proposed channel modeling the improvement of the call blocking rate was analyzed when using the adaptive sector cell system, and computer simulations show that the call blocking rate of the adaptive sector cell system was much lower than that of the fixed sector cell system. Additionally, it shows that the call blocking rate increases severely in the fixed sector cell system while the difference of the call blocking rate was smaller in the adaptive sector cell system, as the user density of the spatial distribution increases.

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A Tree-Based Routing Algorithm Considering An Optimization for Efficient Link-Cost Estimation in Military WSN Environments (무선 센서 네트워크에서 링크 비용 최적화를 고려한 감시·정찰 환경의 트리 기반 라우팅 알고리즘에 대한 연구)

  • Kong, Joon-Ik;Lee, Jae-Ho;Kang, Ji-Heon;Eom, Doo-Seop
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.8B
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    • pp.637-646
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    • 2012
  • Recently, Wireless Sensor Networks (WSNs) are used in many applications. When sensor nodes are deployed on special areas, where humans have any difficulties to get in, the nodes form network topology themselves. By using the sensor nodes, users are able to obtain environmental information. Due to the lack of the battery capability, sensor nodes should be efficiently managed with energy consumption in WSNs. In specific applications (e.g. in intrusion detections), intruders tend to occur unexpectedly. For the energy efficiency in the applications, an appropriate algorithm is strongly required. In this paper, we propose tree-based routing algorithm for the specific applications, which based on the intrusion detection. In addition, In order to decrease traffic density, the proposed algorithm provides enhanced method considering link cost and load balance, and it establishes efficient links amongst the sensor nodes. Simultaneously, by using the proposed scheme, parent and child nodes are (re-)defined. Furthermore, efficient routing table management facilitates to improve energy efficiency especially in the limited power source. In order to apply a realistic military environment, in this paper, we design three scenarios according to an intruder's moving direction; (1) the intruder is passing along a path where sensor nodes have been already deployed. (2) the intruders are crossing the path. (3) the intruders, who are moving as (1)'s scenario, are certainly deviating from the middle of the path. In conclusion, through the simulation results, we obtain the performance results in terms of latency and energy consumption, and analyze them. Finally, we validate our algorithm is highly able to adapt on such the application environments.

A Study on the Present Status and Improving Measure of Sea Charts (해도의 사용실태 조사와 개선방안에 관한 연구)

  • 나송진;정재용;박진수
    • Journal of the Korean Institute of Navigation
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    • v.24 no.1
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    • pp.1-12
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    • 2000
  • The ships over the certain navigation area or her length are required to carry charts under the relevant laws. Charts are indispensible to the ships and fishing vessel, because their crew should know the water depth and location of obstacle in order to avoid danger in the navigation and fishing area. But it was found that many ships do not carry proper charts onboard according to the research marine accidents files of marine accident inquiry agency, and questionnaire survey. Consequently, many ships run aground on the coast and port. This study examined the present status of the coastal ship and the fishing vessels, and explained some problems in the aspect of the covering area, the place, the number of the selling agent and adjoining chart, as well as the geographical and traffic density, the crew on board the ship's characteristics, and so on. In this study we propose the way to solve the problem. firstly, the category of the fishing vessel which should carry the chart on bard under the related laws are required to be lowered to 10 gross tons. Besides a ship inspector should examine if the charts covering the area where to navigate even when the temporary inspection is done are carried on board property. Secondly, the inspection body or the controlling office of ship's entry and departure should check throughly whether the ships concerned carry the chart on board. Thirdly the fishing vessels should used the fishing charts, and the body concerned should train the offices about how to use chart, especiany the difference between Tokyo datum and WGS-84 datum. Fourthly the customized chart such as an atlas like a map, a calenda-type chart, a small chart, as a coated chart needs to be publish for the safety of small ship and fishing vessel. Fifthly, it is advisable to draw a recommended course in the route where the coastal navigate mainly and in the narrow channel, The adjoining area should be improved, as well as the qualify of the chart paper. Sixthly, publication of additional new chart in the southern part of East Sea, the eastern part of South Sea, the western part of South Sea and middle part of Yellow Sea near Incheon port should be thought over. Seventhly, the number of chart selling agent should be increased for the sake of purchaser in proportion to the number of port, and small correction of charts in selling agent must be carried out completely.

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Performance Analysis of an Adaptive Sector System for Terrestrial Station in Ad-hoc Communication System Between Vessels (선박 간 ad-hoc 통신 시스템에서 육상국용 적응 섹터 시스템의 성능 분석)

  • Lee, Hyung-beom;Kim, Seung-geun;Kim, Jun-ho;Kim, Min-sang;Ko, Hak-lim;Im, Tae-ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.2
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    • pp.263-268
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    • 2016
  • A rapid increase of data amount, used in ship-to-ship transmission of safety and logistics information, ships in the inland sea have trouble transmitting real-time information transmission due to an increase in traffic load caused by data transmitted by land station and offshore ships. In this study, therefore, communication is carried out by adaptively controlling the detailed beam width based on the distribution of offshore ships in land station durable in marine environment. Then after the adaptive sector system enabling real-time communication support between ships concentrated in an inland sea and land station is applied, the performance verification is conducted based on the respective Call Blocking Rates of an omnidirectional antenna, fisted sector system, and adaptive sector system. The performance verification result shows that adaptive sector system has better performance than the fixed sector system as the density of ship, q value, increases, and that the smaller the beam width is, the better performance of adaptive sector system will be.

Access Frequency Based Selective Buffer Cache Management Strategy For Multimedia News Data (접근 요청 빈도에 기반한 멀티미디어 뉴스 데이터의 선별적 버퍼 캐쉬 관리 전략)

  • Park, Yong-Un;Seo, Won-Il;Jeong, Gi-Dong
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.9
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    • pp.2524-2532
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    • 1999
  • In this paper, we present a new buffer pool management scheme designed for video type news objects to build a cost-effective News On Demand storage server for serving users requests beyond the limitation of disk bandwidth. In a News On Demand Server where many of users request for video type news objects have to be serviced keeping their playback deadline, the maximum numbers of concurrent users are limited by the maximum disk bandwidth the server provides. With our proposed buffer cache management scheme, a requested data is checked to see whether or not it is worthy of caching by checking its average arrival interval and current disk traffic density. Subsequently, only granted news objects are permitted to get into the buffer pool, where buffer allocation is made not on the block basis but on the object basis. We evaluated the performance of our proposed caching algorithm through simulation. As a result of the simulation, we show that by using this caching scheme to support users requests for real time news data, compared with serving those requests only by disks, 30% of extra requests are served without additional cost increase.

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A geographical study of the Korean Tobacoo forming region (韓國 煙草載培地域의 地理學的 硏究)

  • ;Kim, Kwang Ja
    • Journal of the Korean Geographical Society
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    • v.21
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    • pp.16-37
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    • 1980
  • The purpose of this study is to clarify how the Korean tobacco farming region has been geographically formed by natural and cultural environments, and to examine and cultural environments, and to examine whether it can be recognized as a major part of agricultultural regions. The questions asked in this study are associated with the spatial diffusion of tobacco cultivation, the patterns and processes of the farming region from 1900 to 1960, and the regional characteristics of the concentrated farming area since 1960. The study is inductively approached and most data used were collected from old records and field works. The delineation of the tobacco farming region was derived by applying the concept of the uniform region. Tobacco was introduced through Japan during the years of Kwang Hae Kun (1616-1622). According to the old records, three places, Waekwan, Dongrae, and Ulsan, were the first tobacco raising areas. In the 1700's the well-known tobacco farming regions were scattered all around the nation in places like Jinan, Samdeung, Seongcheon, Gangdong, Yeongweol and Yeongyang. This distributon pattern suggests that tobacco farming in Korea developed spatially along main traffic routes before the 1700's. Untill the 1920's the pattern of tobacco regions was relatively static. Since the 1920's, it has shown a pattern of concentration in the Choongbuk province, where the new highly productive yellow tobacco has been introduced. It was not until the 1960's that yellow tobacco instead of the native variety came to be cultivated all over the country. In the 1960's, the tobacco farming region tended to be concentrated and localized in north western Choongnam, northern Cheonbuk, Choongbuk, and Kyeongbuk including Cheongsong, Andong, and Yeongyang. Since 1970, tobacco production has declined in some of the former major areas of cultivation in terms of its density, while there have appeared highly concentrated areas in Cheongsong and Andong, centered around Yeongyand. There has also emerged a secondary major concentrated area along the coast including such places as Kochang, Yeongkwang and Mooan. The appearance of the Yeongyang tobacco area as the most important core region can be described as follows; at first this area has the disadvantage of being in competition with other places for selling cash crops besides tobacco, because it is located in a mountain zone and it is far from the major metropolises of Seoul and Pusan. Thus has been formed the farming mentality that agricultural management makes the most profit on farming tobacco because tobacco is stable in price and selling routes. As a result of this longstanding belief, these areas (Yeongyang, Cheongsong and Andong) have developed into tobacco concentrated regions. Finally, the tobacco concentrated regions of Korea have changed through time. The factors affecting this change have been the kind of tobacco grown, the monopoly system, agricultural techniques and the expansion of arable land through the clearing of slopes. In conclusion, the research indicates that the localized and concentrated patterns of tobacco cultivation are geographically typical. Thus, recognition of tobacco farming region is important to understanding the agricultural region of Korea as a whole.

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Complement of the Interlocking Logic of ATS for Heterogenous Railway Signaling Systems (이종 철도신호시스템을 위한 기존 자동열차정지 연동로직의 보완)

  • Jeong, Rag-Gyo;Kim, Baek-Hyun;Kang, Seok-Won;Byun, Yeun-Sub;Park, Geon-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.10
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    • pp.702-708
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    • 2016
  • The railway signaling system has evolved to maximize its safety and maintainability based on the experiences in the construction and operation of railway systems. The newly developed systems was established to cope with the changes in an operating environment. In the process of a transition to the new system, both the existing ATS (Automatic Train Stop) and new ATP/ATO (Automatic Train Protection/Automatic Train Operation) systems are operating simultaneously in parallel. In this situation, modifications of the conditions of the interlocking diagram and logic are necessarily required on the existing ATS systems due to the frequent improvements in signaling equipment. This paper reports the enhancement of safety and operational efficiency of the system through an improvement of the security and the interlocking conditions of the existing ATS systems. The independent display of signals for each track was ensured to avoid giving the effect of On/Off signals for the selected track on the opposite side, and the security was improved by adjusting the position and interlocking conditions. In addition, the increased traffic density of railway systems was achieved by removing the unnecessary conditions and detailed signal display, which resulted in enhanced operational efficiency.

A Study on Security Requirements for 5G Base Station (5G 기지국에 대한 보안성평가기준 연구)

  • Hong, Paul;Kim, Yejun;Cho, Kwangsoo;Kim, Seungjoo
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.31 no.5
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    • pp.919-939
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    • 2021
  • As a next-generation communication technology, 5G networks are capable of handling large amounts of traffic based on higher speeds, shorter communication delays, and higher connectivity compared to 4G networks. In this 5G network environment, base stations are installed all over the city at high density due to their characteristics, and are connected to user terminals to provide services. Therefore, if the base station is damaged by a malicious attacker, it is expected to cause great damage to users and society as a whole. So the need for secure communication equipment such as 5G base stations has emerged. Therefore, in this paper, we propose the security functional requirements derived using threat modeling, a systematic methodology for 5G base stations, and the security assurance requirements at the level that can cope with the backdoor issues. The security requirements proposed in this paper can be used for base station design and development to construct a secure network environment as a security evaluation standard for 5G base stations.