• Title/Summary/Keyword: Re-transmission

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A Study on Optimum Design of Worm Gear Reducer Output Pinion (웜기어 감속기 출력 피니언의 최적설계에 관한 연구)

  • Lee, Dong Gyu;Zhen, Qin;Kim, Lae Sung;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.6
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    • pp.153-158
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    • 2017
  • Reducer is a device to transmit and change torque and speed from drive shaft to driven shaft with excellent transmission efficiency, and it is widely used in many areas today. Reduction gear consists of two axes, gear, bearing supporting axes, and housing. The simplest method to transmit rotation or power to multiple axes is to attach circular plates to two axes and contact each other. However, in this case, if increasing number of rotations or if contact pressure is small, because of slipping, it cannot transmit power. For problems for the current reducer case, it is heavy and its assembling and repair is difficult. In addition, there are few studies about manufacturing and performance testing of worm gear reducer, causing lack of the foundation to improve the product competition and the performance.

GA-based Optimal Reactive Power Dispatch Taking Account of Transmission Loss Re-distribution and Voltage Dependent Load Models (송전손실 재분배와 전압의존형 부하모델을 적용한 GA기반의 무효전력 최적배분)

  • Chae, Myung-Suk;Lee, Myung-Hwan;Kim, Byung-Seop;Shin, Joong-Rin
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.350-353
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    • 2000
  • This paper presents an algorithm for Optimal Reactive Power Dispatch(ORPD) problem based on genetic algorithm. Optimal reactive power dispatch is particularized to the minimization of transmission line losses by suitable selection of generator reactive power outputs and transformer tap settings. To reduce system loss and improve voltage profile, two methods, Loss Re-Distribution Algorithm (LRDA) and Voltage Dependent Load Model (VDLM), are applied to ORPD. The proposed methods have been evaluated on the IEEE 30 bus system. Each of results have been compared with result of load flow.

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GA-Based ORPD considering Transmission Losses Re-Distribution (송전손실 재분배를 고려한 유전 알고리즘 기반의 무효전력 최적배분)

  • Chae, Myung-Suck;Lee, Myung-Hwan;Kim, Byung-Seop;Shin, Joong-Rin
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.190-192
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    • 1999
  • This paper presents an algorithm for optimal reactive power dispatch problem based on genetic algorithm. Optimal reactive power dispatch is particularized to the minimization of transmission line losses by suitable selection of generator reactive power outputs and transformer tap settings. To attain for the objective, in this paper, loss re-distribution algorithm(LRDA) is applied to ORPD. The proposed method has been evaluated on the IEEE 30 bus system. Results of the application of the method are compared with a simple genetic algorithm.

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Meanings and Issues of Broadcasting Area (방송 권역의 의미와 쟁점에 대한 연구)

  • Kim, Dae-Ho
    • Korean journal of communication and information
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    • v.19
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    • pp.65-93
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    • 2002
  • This research deals with meanings and issues of 'broadcasting area' in which trans-regional broadcasting media such as satellite broadcasting and webcasting provoked. The issues around broadcasting area have raised the examination of fundamental broadcasting philosophy in Korea, i.e. establishment of broadcasting area intends to foster new media development? or protect local culture and local journalism? After assessing current criticisms around the broadcasting area, this study particularly addresses re-transmission outside the broadcasting area, satellite broadcaster's re-transmission of terrestrial channels, and widening of broadcasting area. This research argues that broadcasting area has lost its raison-etre due to the advent of new communication technology, even though it was maintained to protect regional broadcasting stations. Therefore it argues that now is the right time to change the broadcasting area in the digital media era. This approach could strengthen the competitiveness of regional broadcasting stations and solve the rows surrounding broadcasting areas.

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Wireless Security Transmission Using Algorithm of Multiple-Key Exchange (다중 키 교환 알고리즘을 이용한 무선 보안 전송 기법)

  • Ryu, Dong-Ju;Kim, Gwang-Hyun;Noh, Bong-Nam
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.2
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    • pp.807-810
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    • 2005
  • Constructed network test environment of wireless base for confidentiality guarantee of data and safe transmission that is transmited at Mobile node of Wireless Network environment in this paper. And, progressed research about IKEv2's Multiple-Key Exchange mechanism for efficient security transmission that use IPSec that is built-in to basis to IPv6 of Mobile environment. Have several key to single terminal to solve that is seam at hand off packet transmission process of Mobile Node in Wireless Network and Re-setting for Key and Re-exchange problem that happen frequently and studied technology that move. Key exchange protocol that is used for an experiment loads basically in MIPv6 and used IKEv2 protocol that is used for management and distribution of reliable encryption key between both end. Using network simulator of SSFNet(Scalable Simulation Framework Network Models) in this paper Key exchange delay value of IKEv2's security transmission analyzing comparison Performance measure and studied about problem and improvement way accordingly.

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Epidemiological Characteristics of Re-emerging Vivax Malaria in the Republic of Korea (1993-2017)

  • Bahk, Young Yil;Lee, Hyeong-Woo;Na, Byoung-Kuk;Kim, Jeonga;Jin, Kyoung;Hong, Yeong Seon;Kim, Tong-Soo
    • Parasites, Hosts and Diseases
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    • v.56 no.6
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    • pp.531-543
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    • 2018
  • Historically, Plasmodium vivax malaria has been one of the most highly endemic parasitic diseases in the Korean Peninsula. Until the 1970s, vivax malaria was rarely directly lethal and was controlled through the Korean Government Program administered by the National Malaria Eradication Service in association with the World Health Organization's Global Malaria Eradication Program. Vivax malaria has re-emerged in 1993 near the Demilitarized Zone between South and North Korea and has since become an endemic infectious disease that now poses a serious public health threat through local transmission in the Republic of Korea. This review presents major lessons learned from past and current malaria research, including epidemiological and biological characteristics of the re-emergent disease, and considers some interesting patterns of diversity. Among other features, this review highlights temporal changes in the genetic makeup of the parasitic population, patient demographic features, and spatial distribution of cases, which all provide insight into the factors contributing to local transmission. The data indicate that vivax malaria in Korea is not expanding exponentially. However, continued surveillance is needed to prevent future resurgence.

A Study for Stress Distribution of the High-voltage Transmission Tower Under Wind Forces (풍하중이 작용하는 고용량 송전철탑의 해석을 통한 응력 분포 고찰)

  • Chang, Jin-Won;Kim, Seung-Jun;Park, Jong-Sub;Kang, Young-Jong
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.75-78
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    • 2007
  • The structural methodology in designing a transmission tower have been performed to assume a simple truss behavior. But there're quite differences between a simple truss behavior and a real one. A suitable explanation for a structural stability can be expressed as a semi-rigid connection instead of the assumed hinged connection. This study proposes an alternative structural analysis modelling strategy for the transmission tower design. Proposed element models are truss element model, beam element model, and combined beam-truss element model. The static finite element analysis shows that there's a moment distribution between a mainpost member and the other bracing member.

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Design of Service-adaptive Tactical Data Transmission Protocol for Satellite Communications (위성통신을 위한 서비스 적응적인 전술 데이터 전송 프로토콜 설계)

  • Kim, Sujeong;Lee, Sooho
    • Journal of Satellite, Information and Communications
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    • v.11 no.3
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    • pp.72-79
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    • 2016
  • In this paper, we propose a Service-adaptive Tactical Data Transmission Protocol (STTS) based on Satellite Communications with narrow bandwidth. STTS is designed to provide additional field for scalability and scheduler for reliability of transport stream protocol based on digital broadcasting standard, DVB-S and DVB-S2. It is also verified the effects of lost data packets with narrow bandwidth through the simulator by traffic model and re-transmission of critical data, and checked the design considerations based on STTS system.

16×2.5 Gb/s WDM transmission over 10,880 km using forward error correction (40 Gb/s (16×2.5 Gb/s WDM 신호의 10,880 km 전송실험)

  • 정윤철;전상배;정환석;윤천주;박근주
    • Korean Journal of Optics and Photonics
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    • v.13 no.2
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    • pp.113-116
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    • 2002
  • We demonstrate 16 ch.$\times$2.5 Gb/s WDM transmission over 10,880 km using a re-circulating loop and forward error correction (FEC) code. The performances of all 16 channels were measured to be lower than 10$^{-10}$ .