• Title/Summary/Keyword: 확률제어

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Performance Analysis of Call Admission Control Scheme with Bandwidth Borrowing and Bandwidth Reservation in GEO based Integrated Satellite Network (GEO 기반 위성 네트워크에서의 대역폭 빌림 방법과 대역폭 예약 방법을 이용한 호 수락 제어 성능 분석)

  • Hong, Tae-Cheol;Gang, Gun-Seok;An, Do-Seop;Lee, Ho-Jin
    • Journal of Satellite, Information and Communications
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    • v.1 no.1
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    • pp.12-19
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    • 2006
  • In this paper, we propose the bandwidth borrowing scheme which improves the performance of the cal admission control of the integrated GEO satellite networks. In general, target transmission rates of communications and streaming services are fixed, but data services do not have the target transmission rates. Therefore, we can control the transmission rates for data services flexibly according to the system loading situation. When the available bandwidth of the system is insufficient, the bandwidth borrowing scheme gives the bandwidth to request real time services by the transmission rates control of data services through packet scheduler. We make the queueing model for our system model and demonstrate the results through simulations. The simulation results show that there is a 8.7-35.2 dB gain at the total blocking probability according to the use of bandwidth borrowing scheme.

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A Study on Comparative Analysis of Urban Flood Reduction Measures in Major cities of Northeast Asia (동북아시아 주요도시 홍수 저감대책 비교분석에 관한 연구)

  • Kang, Ho Yeong;Xu, Geng Xin;Park, Kyung Mi;Moon, Young Il
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.605-605
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    • 2015
  • 최근 지구온난화로 인해 전 세계적으로 기상이변이 발생하여 강우량과 집중호우 발생빈도가 증가하는 추세이다. 특히 동북아시아 지역은 인구밀도가 높아 강우량 및 집중호우 발생빈도 증가에 따른 도시홍수 발생확률이 높으며 홍수피해가 가중될 수 있다. 또한 도심지에 위치한 하천의 외수위 상승 및 배수시설 설계빈도 이상의 강우의 발생빈도가 증가하여, 기존 홍수방어대책으로는 제어하기 어려운 실정이다. "수자원장기종합계획(2011~2020), 2011, 국토해양부"에 따르면 기상청의 한반도 장기 미래 전망을 21세기말(2071년~2100년)에 대해 한국 평년 기온은 $4^{\circ}C$정도 상승하고, 강우량도 증가할 것으로 전망하고 있다. 따라서 도심지에 위치한 하천의 외수위 상승 및 배수실 설계빈도 이상의 강우가 빈번히 발생하여 기존 홍수방어대책으로는 제어하기 어려운 실정이다. 본 연구에서는 연구 대상지역인 서울, 북경, 도쿄 지역의 과거 도시홍수 사례의 비교분석을 통하여 집중호우 빈발, 기존 방재시설물의 기후변화 대응능력 부족, 저지대지역 지형적 영향, 무분별한 도시개발로 인한 도시지역 불투수면적의 증가, 고령화와 재해취약계층 등 여러 가지 도시홍수 재해 영향인자들을 제시하였다. 앞으로 도시홍수 발생의 근본 원인 파악 및 홍수관리 효과를 최대화 시킬 수 있는 대책 설립에 대한 연구가 필수적이다. 본 연구에서는 동북아시아 지역 도시홍수로 인한 인명 재산 피해를 최소화하기 위해 기존 한국, 중국, 일본 삼국의 주요 도시별 홍수에 대한 구조적 비구조적 방어대책을 종합하고 비교분석을 실시하였다. 향후, 국내외 도시홍수 저감대책 수립을 위한 참고자료로 활용될 수 있을 것으로 기대된다.

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Implementation of Exclusive OR-Based Video Streaming System (배타적 논리합 기반 비디오 스트리밍 시스템의 구현)

  • Lee, Jeong-Min;Ban, Tae-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.7
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    • pp.1091-1097
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    • 2022
  • In this paper, we implement the eXclusive OR-based Cast (XC) system that is a video streaming system using exclusive OR operations, and measure various performance metrics in wireless local area network (WLAN) environments. In addition, we investigate the performance improvement of the XC system considering various practical video streaming environments, while conventional studies analyzed the performance of XC through computer simulations in limited environments. To this end, we propose new control messages such as STR_REQ_MSG (SRM) that clients transmit to a video streaming server and STR_CON_MSG (SCM) that is used for the video streaming server to control the clients, and develop a new protocol by using the new control messages. According to the various measurement results using the implemented XC system, XC video streaming system can reduce the consumption of network bandwidth by 8.6% on average and up to 25% compared to the conventional video streaming system. In addition, the outage probability can be also reduced up to 76%.

QoS-Aware Call Admission Control for Multimedia over CDMA Network (CDMA 무선망상의 멀티미디어 서비스를 위한 QoS 제공 호 제어 기법)

  • 정용찬;정세정;신지태
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.12
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    • pp.106-115
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    • 2003
  • Diverse multimedia services will be deployed at hand on 3G-and-beyond multi-service CDMA systems in order to satisfy different quality of service (QoS) according to traffic types. In order to use appropriate resources efficiently the call admission control (CAC) as a major resource control mechanism needs to be used to take care of efficient utilization of limited resources. In this paper, we propose a QoS-aware CAC (QCAC) that is enabled to provide service fairness and service differentiation in accordance with priority order and that applies the different thresholds in received power considering different QoS requirements such as different bit error rates (BER) when adopting total received power as the ceil load estimation. The proposed QCAC calculates the different thresholds of the different traffic types based on different required BER applies it for admission policy, and can get service fairness and differentiation in terms of call dropping probability as a main performance metric. The QCAC is aware of the QoS requirement per traffic type and allows admission discrimination according to traffic types in order to minimize the probability of QoS violation. Also the CAC needs to consider the resource allocation schemes such as complete sharing (CS), complete partitioning (CP), and priority sharing(PS) in order to provide fairness and service differentiation among traffic types. Among them, PS is closely related with the proposed QCAC having differently calculated threshold per each traffic type according to traffic priority orders.

Optimal design of nonlinear damping system for seismically-excited adjacent structures using multi-objective genetic algorithm integrated with stochastic linearization method (추계학적 선형화 방법 및 다목적 유전자 알고리즘을 이용한 지진하중을 받는 인접 구조물에 대한 비선형 감쇠시스템의 최적 설계)

  • Ok, Seung-Yong;Song, Jun-Ho;Koh, Hyun-Moo;Park, Kwan-Soon
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.6
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    • pp.1-14
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    • 2007
  • Optimal design method of nonlinear damping system for seismic response control of adjacent structures is studied in this paper. The objective functions of the optimal design are defined by structural response and total amount of the dampers. In order to obtain a solution minimizing two mutually conflicting objective functions simultaneously, multi-objective optimization technique based on genetic algorithm is adopted. In addition, stochastic linearization method is embedded into the multi-objective framework to efficiently estimate the seismic responses of the adjacent structures interconnected by nonlinear hysteretic dampers without performing nonlinear time-history analyses. As a numerical example to demonstrate the effectiveness of the proposed technique, 20-story and 10-story buildings are considered and MR dampers of which hysteretic behaviors vary with the magnitude of the input voltage are considered as nonlinear hysteretic damper interconnecting two adjacent buildings. The proposed approach can provide the optimal number and capacities of the MR dampers, which turned out to be more economical than the uniform distribution system while maintaining similar control performance. The proposed damper system is verified to show more stable performance in terms of the pounding probability between two adjacent buildings. The applicability of the proposed method to the design problem for optimally placing semi-active control system is examined as well.

Development of Indoor Navigation Control System for Swarm Multiple AR.Drone's (실내 환경에서의 AR.Drone 군집 비행 시스템 개발)

  • Moon, SungTae;Cho, Dong-Hyun;Han, Sang-Hyuck;Rew, DongYoung;Gong, HyunCheol
    • Aerospace Engineering and Technology
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    • v.13 no.1
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    • pp.166-173
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    • 2014
  • Recently, small quadcopters have been widely used in various areas ranging from military to entertainment applications because interest in the quadcopter increases. Especially, the research on swarm flight which control quadcopters simultaneously without any collision can increase success probability of a important mission. In addition the swarm flight can be applied for demonstrating choreographed aerial maneuvers such as dancing and playing musical instruments. In this paper, we introduce multiple AR.Drone control system based on motion capture for indoor environment in which quadcopters can recognize current position each other and perform scenario based mission.

The Effects of DC Offset on the Performance of Direct-Conversion Mobile Receiver in WCDMA System (WCDMA 시스템 직접변환 단말기 수신기에서 DC 오프셋에 의한 성능영향)

  • 이일규
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.7
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    • pp.730-735
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    • 2004
  • This paper describes what brings about DC offset and the impact or the DC offset on the performance or direct-conversion mobile receiver in WCDMA system. The performance degradation of $E_{b}/N_{o}$ due to the DC offset is presented through simulation result. Direct-conversion RF Transceiver which has the function of DC offset control is implemented and then applied to the WCDMA test-bed for the performance evaluation. The receiver performance degradation of $E_{c}/I_{o}$ is evaluated and analyzed by varying DC offset value. The practical test showed the minimum requirement of DC offset value to meet system performance.

Characteristics of Parameters for the Distribution of fatigue Crack Growth Lives wider Constant Stress Intensity factor Control (일정 응력확대계수 제어하의 피로균열전파수명 분포의 파라메터 특성)

  • 김선진
    • Journal of Ocean Engineering and Technology
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    • v.17 no.2
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    • pp.54-59
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    • 2003
  • The characteristics of the parameters for the probability distribution of fatigue crack growth life, using the non-Gaussian random process simulation method is investigated. In this paper, the material resistance to fatigue crack growth is treated as a spatial random process, which varies randomly on the crack surface. Using the previous experimental data, the crack length equals the number of cycle curves that are simulated. The results are obtained for constant stress intensity factor range conditions with stress ratios of R=0.2, three specimen thickness of 6, 12 and 18mm, and the four stress intensity level. The probability distribution function of fatigue crack growth life seems to follow the 3-parameter Wiubull,, showing a slight dependence on specimen thickness and stress intensity level. The shape parameter, $\alpha$, does not show the dependency of thickness and stress intensity level, but the scale parameter, $\beta$, and location parameter, ${\gamma}$, are decreased by increasing the specimen thickness and stress intensity level. The slope for the stress intensity level is larger than the specimen thickness.

Design and Development of Underwater Drone for Fish Farm Growth Environment Management (양식장 생육 환경관리를 위한 수중 드론 설계 및 개발)

  • Yoo, Seung-Hyeok;Ju, Yeong-Tae;Kim, Jong-Sil;Kim, Eung-Kon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.5
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    • pp.959-966
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    • 2020
  • With the growing importance of the fishery industry and the rapid growth of the aquaculture industry, research on smart farms through ICT convergence in the aquaculture field is in progress. To enable monitoring of the growing environment at the farm site, an underwater drone drive unit, an image collection device, an integrated controller for posture stabilization, and a remote control device capable of controlling and controlling drones through real-time underwater images were proposed, and design, development, and tests were conducted. By utilizing underwater drones, it is possible to replace the supply and demand of manpower and high-cost work in the aquaculture industry, and to manage fish farms in a stable manner by reducing the probability of farming deaths.

Reliability Analysis of the 2-Dimensional Ring-Banyan Network (2차원 링-밴얀 망의 신뢰성 분석)

  • Park, Jae-Hyun
    • Journal of KIISE:Information Networking
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    • v.34 no.4
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    • pp.256-261
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    • 2007
  • 2-Dimensional Ring-banyan network is a high-performance fault-tolerant switching network using a deflection self-routing. The throughput of the switching network is better than that of Cyclic Banyan network under non-uniform traffic. In this paper, we present an analytic reliability analysis of the fault-tolerant switching network. We present the Mean-Time-to-Failure that is calculated by using probabilistic model. This model also takes into account a hardware complexity. In case of $16\;{\times}\;16$ size, the presented switching network is 1.275 times more reliable than Hui's switching network. And it is 1.510 times more reliable than Hui's network in case of $64\;{\times}\;64$ size.