• Title/Summary/Keyword: Protection systems

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A Comparative Study on Protected Area Management in South Korea, Japan and China (한·일·중 3국의 보호지역 관리 비교연구)

  • Lee, Min-Ju;Lee, Gwan-Gyu;Sung, Hyun-Chan;Lee, Dong-Kun;Lee, Hyun-Woo;Kim, Joon-Soon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.16 no.1
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    • pp.71-82
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    • 2013
  • This study has been carried out with the purpose of coming up with suggestions for designation of domestic protection areas and improvement of their management through a comparative analysis of the systems of management of the protection areas in South Korea, Japan and China. Starting with the designation of natural reserves in 1962, South Korea has prepared legal systems for preserving ecosystems and biodiversity, while continuing to designate protected areas. As the state has so far monopolized the designation and management of all South Korean protection areas that take up 10.8% of its entire land area (as of Dec. 2011), with such persisting issues as multiple designations of one and the same area for protection, overlapping management authorities, and management of privately owned land in the protection areas. In Japan, which has protected area sizes and relevant legal systems similar to those in South Korea, the state provides the basic framework for management, while delegating most of the duties related to direct operation and management to specific municipalities. China, with an integrated administrative management of protected areas, has related government offices and municipalities responsible for the designation and management of individual protected areas. South Korea needs to provide a legally based support system that would further enhance the value of areal protection and contribute to the promotion of local economy and community.

An Efficient UEP Transmission Scheme for MIMO-OFDM Systems (MIMO-OFDM 시스템을 위한 효율적인 UEP 전송기법 제안)

  • Lee, Heun-Chul;Lee, Byeong-Si;Sundberg, Carl-Erik W.;Lee, In-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.5C
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    • pp.469-477
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    • 2007
  • Most multimedia source coders exhibit unequal bit error sensitivity. Efficient transmission system design should therefore incorporate the use of matching unequal error protection (UEP). In this paper, we present and evaluate a flexible space-time coding system with unequal error protection. Multiple transmit and receive antennas and bit-interleaved coded modulation techniques are used combined with rate compatible punctured convolutional codes. A near optimum iterative receiver is employed with a multiple-in multiple-out inverse mapper and a MAP decoder as component decoders. We illustrate how the UEP system gain can be achieved either as a power or bandwidth gain compared to the equal error protection system (EEP) for the identical source and equal overall quality for both the UEP and EEP systems. An example with two/three transmit and two receive antennas using BPSK modulation is given for the block fading channel.

Trade-off between Resource Efficiency and Fast Protection for Shared Mesh Protection

  • Cho, Choong-hee
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.7
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    • pp.2568-2588
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    • 2021
  • Shared mesh protection (SMP) protects traffic against failures occurring in a working path, as with linear protection, and allows resource sharing of protection paths with different endpoints. The SMP mechanism coordinates multiple protection paths that require shared resources when failures occur on multiple working paths. When multiple failures occur in SMP networks sharing limited resources, activation can fail because some of the resources in the protection path are already in use. In this case, a node confirming that a resource is not available has the option to wait until the resource is available or to withdraw activation of the protection path. In this study, we recognize that the protection switching time and the number of protected services can be different, depending on which option is used for SMP networks. Moreover, we propose a detailed design for the implementation of SMP by considering options and algorithms that are commonly needed for network nodes. A simulation shows the performance of an SMP system implemented with the proposed design and utilizing two options. The results demonstrate that resource utilization can be increased or protection switching time can be shortened depending on the option selected by the network administrator.

Development of Current-based Compact Digital Protective Relay for Induction Motor Protection (중용량 전동기보호를 위한 전류형 디지털 보호계전기 개발)

  • Jung, Jong-Jin;Kim, Joong-Pyo;Shin, Jong-Han;Park, Jang-Soo
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.140-142
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    • 2005
  • This paper describes the current- based compact digital motor protective relay for low and high voltage induction motors, which are widely used in industrial and commercial power systems. The existing protective relays for motor protection had only overload, short circuit, reverse phase, open circuit and grounding protective elements, and measurement, start/stop control function. But in present day, for automation system, various functions are required, especially motor management and sequence control function and more. To meet these requirements, we developed an economic current-based compact digital motor protective relay which had various function to control, manage and monitor the induction motor.

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Analysis of Surge Behavior and Protection Method in the Underground Distribution Systems with Branch Lines (분기선로가 포함된 지중배전계통에서 서지특성 해석 및 보호방안에 관한 연구)

  • Lee, Jang-Geun;Lee, Jong-Beom;Lee, Jae-Bong;Kim, Byoung-Sook
    • Proceedings of the KIEE Conference
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    • 2006.11a
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    • pp.148-150
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    • 2006
  • This paper describes the overvoltage at the branch line in underground distribution systems when the direct lightning surge strikes on conductor of overhead line. Distribution systems are very complex because it includes many branch lines, transformers, switches and so on. Therefore model system consists of overhead distribution lines, underground cable include branch lines, lightning source and switches. Analysis are performed using EMTP to understand and evaluate the surge behavior on branch lines considering various conditions in underground distribution systems. Simulation results show overvoltage with location in various cases. It is evaluated that result will be used to establish protection methods in actual underground distribution systems.

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Design and Implementation of Digital Motor Control Center Including Load Control Function (부하제어 기능을 갖는 디지털형 전동기제어반의 설계 및 구현)

  • 우천희;강신준;이덕규;구영모;김학배;이성환
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.7
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    • pp.868-875
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    • 1999
  • In this paper, digital motor control center using protection relay is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which have various load environments and capacities in power systems. Digital motor control center is employed by power supervisory control systems without separate remote terminal unit and transducers adding communicational ability. Also we develope a maximum demand controller to control the load effectively at peak status and a power factor controller to minimize real power losses and improve the power factor. Therefore, when using the developed controller, real time computation is possible by loading DSP in hardware and applying real-time kernel which can convert each algorithm to task module.

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A Study on Analysis Method of Underwater Electric Field Signature due to Ship's Corrosion and Corrosion Protection System (선체 부식 및 부식 방지장치에 의한 수중 전기장 신호 해석 방안 연구)

  • Chung, Hyun-Ju;Yang, Chang-Seob;Jeon, Jae-Jin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.11 no.2
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    • pp.43-52
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    • 2008
  • The galvanic corrosion of a vessel, or systems fitted to minimize the ship's corrosion such as ICCP (Impressed Current Cathodic Protection) system and sacrificial anodes, can lead to significant electrical current flow in the sea. The presence of vessel's current sources associated with corrosion will give rise to detectable electric field surrounding the vessel and can put it at risk from mine threats. For this reason, it is necessary to design corrosion protection systems so that they don't only prevent a hull corrosion but also minimize the electric field signature. In this paper, we describe theoretical backgrounds of underwater electric field signature due to corrosion and corrosion protection system on naval vessels and analysis results of the electric field according to the ship's hull and it's propeller coating damage and ICCP anode displacement.

A Study on the Reactor Protection System Composed of ASICs

  • Kim, Sung;Kim, Seog-Nam;Han, Sang-Joon
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.11a
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    • pp.191-196
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    • 1996
  • The potential value of the Application Specific Integrated Circuits(ASIC's) in safety systems of Nuclear Power Plants(NPP's) is being increasingly recognized because they are essentially hardwired circuitry on a chip, the reliability of the system can be proved more easily than that of software based systems which is difficult in point of software V&V(Verification and Validation). There are two types of ASIC, one is a full customized type, the other is a half customized type. PLD(Programmable Logic Device) used in this paper is a half customized ASIC which is a device consisting of blocks of logic connected with programmable interconnections that are customized in the package by end users. This paper describes the RPS(Reactor Protection System) composed of ASICs which provides emergency shutdown of the reactor to protect the core and the pressure boundary of RCS(Reactor Coolant System) in NPP's. The RPS is largely composed of five logic blocks, each of them was implemented in one PLD, as the followings. A). Bistable Logic B). Matrix Logic C).Initiation Logic D). MMI(Man Machine Interface) Logic E). Test Logic.

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Apparatus on Corrosion Protection and Marine Corrosion of Ship (선박의 해양 부식과 부식방지 장치)

  • Kim, Seong-Jong
    • Journal of Surface Science and Engineering
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    • v.44 no.3
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    • pp.105-116
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    • 2011
  • Ships and offshore structures are exposed to harsh marine environments, and maintenance and repair are becoming increasingly important to the industry and the economy. The major corrosion phenomenons of metals and alloys in marine environment are pitting corrosion, stress corrosion cracking, crevice corrosion, fatigue corrosion, cavitation-erosion and etc. due to the effect of chloride ions and is quite serious. Methods of protection against corrosion can generally be divided into two groups: anodic protection and cathodic protection. Anodic protection is limited to the passivity characteristics of a material in its environment, while cathodic protection can apply methods such as sacrificial anode cathodic protection and impressed current cathodic protection. Sacrificial anode methods using Al and Zn alloys are widely used for marine structures and vessels intended for use in seawater. Impressed current cathodic protection methods are also widely used in marine environments, but tend to generate problems related to hydrogen embrittlement caused by hydrogen gas generation. Therefore, it is important to the proper maintenance and operation of the various corrosion protection systems for ship in the harsh marine environment.