• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1964_1965
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• 2009

최근 경제성장과 함께 생활수준의 향상으로 인하여 홈 게이트웨이는 디지털 홈 가전기기에 초고속 통신망 접속 기능을 제공하며 각종 기기들을 하나로 네트워크화 하는 중요한 기능을 담당하게 된다. 전력선 통신은 전력선을 매체로 하기 때문에 신규선로의 포설 없이 가전기기 및 정보화 서비스 모뎀들의 네트워크화에 용이할 뿐만 아니라 커버리지 확장에도 뛰어나서 디지털 가전, 원격검침, 전력설비 감시제어, 국가 재난 감시 시스템 등의 기본 통신 방식으로 가장 유력한 기술로써 디지털 가전을 포함한 유비쿼터스 전기설비 네트워크 구성에서 필수적 기술로 채택되고 있기 때문에 지능형 홈 네트워크, 전력IT 부가 서비스, 설비감시 네트워크, 유비쿼터스 네트워크 관련 기술에 대한 파급 효과가 매우 크며, 디지털 가전의 기본 통신 방식으로 가장 유력한 기술로써 디지털 가전 구성에서 필수적 기술로 채택되고 있다. 본 연구에서는 전력선통신모뎀을 이용하여 가전기기의 전력 소비를 감지할 수 있는 센서를 내장한 전력선 통신기반의 전력 감시 모듈을 개발하여 실시간 원격 모니터링을 통해 소비전력 패턴을 작성한다. 그리고 전력감시 모듈에 연결된 가전기기의 소비전력 패턴 분석을 통해 전력소비 이상 유무를 감지할 수 있는 알고리즘을 개발, 탑재하여 이상 유무를 판단하고 전력소비가 급증할 시 자동으로 전력을 차단하여 화재나 누전의 위험을 방지한다. 이에 본 연구는 전력감시 및 이상전력 차단기능을 갖는 저전력 전력선통신 모뎀 개발에 관한 것이다.

• Journal of the Korea Computer Industry Society
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• v.3 no.12
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• pp.1651-1658
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• 2002

Recently power cable used generally in Korea, because installation is very simple and it has high stability. It confirms to the requirements of IEEE std. 404-1993 by factory testing, but many problems of insulated cable systems are caused by internal defects of the joint part which have to be mounted ensile. Especially, fault rates are arise from impurities or voids. A suitable solution for a monitoring of power cable during the after-laying test and service is partial discharge detection. The artificial defects between cable joint(EPR) and insulator(XLPE) interface are considered in this research to investigating the partial discharge characteristics. ${\varphi}$-q-n properties were detected using data acquisition system and Maximum charge($q_{max}$), repetition rate(${\={n}$), average charge(${\={q}$), Unbalance rate of ${\={n}$ and ${\={q}$ are calculated in order to analysis partial discharge properties quantitatively from this statistic value.

• Geotechnical Engineering
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• v.9 no.3
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• pp.23-34
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• 1993

Model pile teats, using large calibration chamber in which the stress state and the relative density can be controlled, were performed in order to study on the effect of soil condition on the behavior of open-ended steel pipe pile. The model pipe pile was made up of two pipes to separately measure each component of bearing capacity of open -ended steel pipe pile. According to the tests results, pile plugging and driving resistance of the pile installed in sand were primarily dependent on the horizontal stress and the relative density. Plug bearing capacity, outside skin fricition and total bearing capacity were also mainly dependent on the horizontal stress and relative density. Moreover, the ratio of the horizontal stress acting on the outside wall of open -ended pipe pile after installation to the original horizontal stress was not nearly affected by original value of horizontal stress. It is bigger than one in the case of dense deposit, equal to one for medium deposit, and smaller than one for very loose deposit. It seems to be mainly dependent on the relative density for a given soil.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.79-87
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• 2003

Underground flexible pipes for electric cables are subject to external loads and surrounding soil pressure. Particularly, strain of flexible pipes is of great concern in terms of safety and maintenance of electric cables. In this paper, stress and strain of flexible pipes with two types of installation gap, ie, l0cm and naught, were compared to investigate the structural integrity of pipes from actual field test. The effect of degree of compaction and burial depth were also investigated to simulate the variety of construction situation. The results of the field test show that the strain criteria were satisfied under the burial depths of 80cm, 100cm and 120cm regardless of installation gap.

• Information and Communications Magazine
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• v.11 no.2
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• pp.77-89
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• 1994

High speed optical fiber transmission technology has been remarkably improved during the past 20 years. This paper presents recent research status and future technological issues for the future information society, that is, the Tb/s transmission by frequency division multiplexing and the ultra long-distance by optical soliton transmission. Erbium-doped fiber amplifier and recent optical technology have brought optical transmission system of up to 10 Gb/s to the point of commercialization. Taking into account the future super information highway, that is, B-ISDN network, ultra wide-band picture-based information can be provided for many subscribers via existing optical fiber cables. However, to achieve the high speed transmission, the technologies must be developed not only for transmission lines but also for transmission nodes. Since the conventional signal transmission/processing technique using electronics has the limit in its speed, novel photonic technology is being developed for this purpose. On the other hand, optical solitons propagate stably through optical fibers, without pulse broadening effect of the fiber dispersion. Since the pulse broadening effect becomes serious as the transmission speed increases, optical solitons is the important technologies to realize the high speed, long distance transmission.

• Information and Communications Magazine
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• v.15 no.7
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• pp.75-94
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• 1998

In this paper, HFC CATV networks are introduced. HFC CATV networks are currently considered as a most effective and plausible solution for subscriber access networks in the information superhighway, among others such as ADSL and B-WLL. The advantages of HFC CATV networks include its broad upstream and downstream channel bandwidths, much wider than PSTN's and its readiness. The HFC CATV networks are already well spread among the general subscribers in Korea. This fact will shorten the installation period and significantly reduce its cost. In addition, The structure and channel environment of the HFC CATV networks are introduced. At the same time, in this paper included are major problems in the HFC CATV networks and the solutions for these problems. Also discussed are data transmission, medium access control, IEEE802.14, and MCNS for standardizations. Moreover, additional telecommunications service activities in both Korea and other countries, using HFC CATV networks are also included. The topics which are covered in detail are the ones such as interoperation between HFC CATV networks and trunk line and the digital transmission performance test for the CATV networks. In the performance test, it is concluded that HFC CATV networks can satisfy the QoS for various additional services if the number of the subscribers in a cell is limited to less than 500 and other minor requirements are satisfied. Based on all these discussions and conclusions, HFC CATV networks are suggested in this paper for the subscriber access networks of the so called information superhighway.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.279-280
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• 2009

최근 경세성장과 함께 생활수준의 향상으로 인하여 에너지 수요는 매년 증가하고 있으며 그 중에서 하나인 전력수요도 역시 급격히 늘어나고 있는 추세이다. 이와 더불어 투자자원 및 입지확보의 어려움, 환경제약의 문제로 전력 공급의 어려움은 날로 증가되고 있다. 따라서 수요증가를 전력공급 능력의 증진뿐만 아니라 수요관리 측면에서도 필요성이 대두되고 있다. 전력선 통신은 전력선을 매체로 하기 때문에 신규선로의 포설 없이 가전기기 및 정보화 서비스 모뎀들의 네트워크화에 용이할 뿐만 아니라 커버리지 확장에도 뛰어나서 디지털 가전, 원격검침, 전력설비 감시제어, 국가 재난 감시 시스템 등의 기본 통신 방식으로 가장 유력한 기술로써 디지털 가전을 포함한 유비쿼터스 전기설비 네트워크 구성에서 필수적 기술로 채택되고 있기 때문에 지능형 홈 네트워크, 전력IT 부가서비스, 설비감시 네트워크, 유비쿼터스 네트워크 관련 기술에 대한 파급 효과가 매우 크며, 디지털 가전의 기본 통신 방식으로 가장 유력한 기술로써 디지털 가전 구성에서 필수적 기술로 채택되고 있기 때문에 지능형 홈 네트워크 관련 기술에 대한 파급 효과가 매우 크다. 본 연구에서는 전력선통신모뎀을 이용하여 가전기기의 전력 소비를 감지할 수 있는 센서를 내장한 전력선 통신기반의 전력 감시 모듈을 개발하여 실시간 원격 모니터링을 통해 소비전력 패턴을 작성한다. 그리고 전력감시 모듈에 연결된 가전기기의 소비전력 패턴 분석을 통해 전력소비 이상 유무를 감지할 수 있는 알고리즘을 개발, 탑재하여 이상유무를 판단하고 전력소비가 급증할 시 자동으로 전력을 차단하여 화재나 누전의 위험을 방지한다. 이에 본 연구는 전력선통신을 이용하여 전력소비감시 및 이상전력차단에 관한 연구에 관한 것이다.

• Journal of Digital Contents Society
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• v.17 no.4
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• pp.257-263
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• 2016

Cable drum schedule is the final step for the electrical equipment of the power plant, and is assigned cables to efficiently cable drum. In this paper, we have implemented an automated program which cables are scheduled in accordance with the capacity of the cable drum for each cable code. Proposed cable drum schedule was applied to the dynamic programming algorithm to effectively solve the optimization problem, and the implemented program is conducted so as to verify the proposed model. The experiment results show that implemented program eliminates the errors that can occur existing method, so we were able to reduce the design time of cable drum schedule. Cables for the electrical equipment of the power plant is designed to at least 2 million units or more. Thus the automation program to provide applies, it is considered that the design time of the cable drum schedule can be greatly reduced without serious error.

• Geotechnical Engineering
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• v.12 no.5
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• pp.89-102
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• 1996

In order to investigate the characteristics of pressure drainage for geotextile, small-scale model tests were carried out for the horizontal and vertical geotextile drain to accelerate consolidation of foundation under embankment for the purpose of foundation reinforcement. According to the result of this study, the accumulative drainage discharge is found to increase as compressive stress of geotextile increases with logarithmic function. The drainage discharge under each step of compressive stress linearly increases with the increase of hydraulic head and its increasing rate is smaller when the compressive stress is higher. The drainage discharge shows to be greater when the number of geoteztile layers is more and the foundation material is finer. The relationship between transmissivity of geogextile and drainage discharge has positive correlation and the rate of increase is appeared to be the same regardless of foundation material and hydraulic head. And it proves that the drainage capacity of geotextile drain is determined by the transmissivity of geoteztile.

• Journal of the Korean Geotechnical Society
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• v.20 no.4
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• pp.29-38
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• 2004

A finite element nonlinear stress-deformation model with multi-interface element is applied to the stability analysis of waste landfill slope. Strength parameters of waste and geosynthetic materials are obtained from the triaxial test of waste and the direct shear test of geosynthetics, respectively. The landfill models used for the numerical models are fit to regulations of the Korean waste management law. The results of the strength tests showed linear behavior for the waste and nonlinear behavior for the eosynthectic materials. The stability analysis with multi-interface element for the geosynthetic materials in the liner system showed large shear stress and slippage at the boundary of the foundation and the slope of the waste fill. This analysis verified the necessity of multi-interface analysis for waste landfills with composite liners.