• Title/Summary/Keyword: Simulator level

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Efficient Resource Allocation Technique for LTE-Advanced based Interference Avoidance of Heterogeneous Network (LTE-Advanced 기반 이기종 네트워크 시스템의 간섭회피를 위한 효율적인 자원할당 기법)

  • Jang, Sung-Won;Seong, Hyeon-Kyeong
    • Journal of the Institute of Convergence Signal Processing
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    • v.17 no.1
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    • pp.46-52
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    • 2016
  • LTE-Advanced system consisting of the number of cells in the cellular environment because it is built to allow efficient use of limited frequency resources of adjacent cell interference avoidance should be considered. Transition services in accordance with the development of the mobile communication technology, wireless multimedia content from voice-centric mobile communications services and causing a lot of mobile data traffic, such as smart phones and tablet terminals spread of a data-driven surge in mobile data traffic base stations in urban areas by increasing became a reality that can not be prevented. In this paper, we propose a new Hybrid resource allocation technique for improving the performance of the cell boundary and analyzed the performance of the proposed new techniques to perform the simulation using LTE-Advanced system level simulator based on 19cell of cellular system model.

The Classification of Congestion and Wireless Losses for TCP Segments Using ROTT (상대전송지연시간을 이용한 TCP 세그먼트의 혼잡 손실과 무선 손실 구분 알고리즘)

  • Shin, Kwang-Sik;Lee, Bo-Ram;Kim, Ki-Won;Jang, Mun-Suck;Yoon, Wan-Oh;Choi, Sang-Bang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.8A
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    • pp.858-870
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    • 2007
  • TCP is popular protocol for reliable data delivery in the Internet. In recent years, wireless environments with transmission errors are becoming more common. Therefore, there is significant interest in using TCP over wireless links. Previous works have shown that, unless the protocol is modified, TCP may perform poorly on paths that include a wireless link subject to transmission errors. The reason for this is the implicit assumption in TCP that all packet losses are due to congestion which causes unnecessary reduction of transmission rate when the cause of packet losses are wireless transmission errors. In this paper, we propose a new LDA that monitors the network congestion level using ROTT. And we evaluate the performance of our scheme and compare with TCP Veno, Spike scheme with NS2(Network Simulator 2). In the result of our experiment, our scheme reduces the packet loss misclassification to maximum 55% of other schemes. And the results of another simulation show that our scheme raise its transmission rate with the fairness preserved.

Power Optimization Method Using Peak Current Modeling for NAND Flash-based Storage Devices (낸드 플래시 기반 저장장치의 피크 전류 모델링을 이용한 전력 최적화 기법 연구)

  • Won, Samkyu;Chung, Eui-Young
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.1
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    • pp.43-50
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    • 2016
  • NAND flash based storage devices adopts multi-channel and multi-way architecture to improve performance using parallel operation of multiple NAND devices. However, multiple NAND devices consume higher current and peak power overlap problem influences on the system stability and data reliability. In this paper, current waveform is measured for erase, program and read operations, peak current and model is defined by profiling method, and estimated probability of peak current overlap among NAND devices. Also, system level TLM simulator is developed to analyze peak overlap phenomenon depending on various simulation scenario. In order to remove peak overlapping, token-ring based simple power management method is applied in the simulation experiments. The optimal peak overlap ratio is proposed to minimize performance degradation based on relationship between peak current overlapping and system performance.

IDS Performance on MANET with Packet Aggregation Transmissions (패킷취합전송이 있는 MANET에서 IDS 성능)

  • Kim, Young-Dong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.6
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    • pp.695-701
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    • 2014
  • Blackhole attacks having a unauthorized change of routing data will cause critical effects for transmission performance. The transmission performance will be improved to the a certain level by using or having IDS(Intrusion Detection System)/IPS(Intrusion Prevention System) as countermeasures to blackhole attacks. In this papar, the effects of IDS to ene-to-end performance of packet aggregation transmission are analyzed on MANET(Mobile Ad-hoc Network) with IDS under blackhole attacks. MANET simulator based on NS-2 is used to analyze performance parameters as MOS, connection ratio, delay and packet loss rate as standard performance parameters, an another performance factor which is suggested in this paper. VoIP(Voice over Internet Protocol) traffics, one of voice services, is used for performance analysis. A suggestion for IDS implementation on MANET with packet aggregations under blackhole is shown as one of results.

End-to-End Performance of Packet Aggregation Transmission on MANET under DDoS Attacks (DDoS 공격이 있는 MANET에서 패킷취합전송의 종단간 성능)

  • Kim, Young-Dong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.6
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    • pp.689-694
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    • 2014
  • DDoS attacks on MANET makes disable any node which support network function, cause critical results as a stopping of entire network service or separation to some parts. Packet aggregation, which gather some pieces of short length into a certain length of data, improves transmission performances on MANETs. In this paper, some effects on transmission performance of packet aggregation transmission be caused by DDoS Attacks are measured and analyzed in point of end-to-end level. MANET simulator, based on NS-2, is used for measurement end-to-end performances. MOS, connection rate, delay and packet loss rate is used as performance parameters. VoIP traffic is used for object service measurement. Finally, it is suggested that number of packet aggregation is more then 4 for keeping the transmission quality over MANETs under DDoS attacks.

Design of a Double-Faced Window Printed Antenna for Aircraft Applications (항공기용 양면 인쇄형 글래스 안테나 설계)

  • Byun, Gang-Il;Han, Wone-Keun;Choo, Ho-Sung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.2
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    • pp.131-139
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    • 2011
  • In this paper, we propose a double-faced window printed antenna for aircraft applications. The proposed antenna structure consists of a feeding line and a multi-loop radiator located on different sides of the window to use the limited given-area effectively. The proposed antenna is optimized by the genetic algorithm in conjunction with the FEKO EM simulator. The optimized antenna is built and installed on a 1/10 sized KUH-Surion mock-up and antenna performances such as the reflection coefficient and the radiation patterns are measured. The optimized antenna shows a half power matching bandwidth of about 33 % at 60 MHz and an average bore-sight gain of about -3.49 dBi. To verify the reception capability of the optimized antenna, we simulated the received power according to a flight scenario. The result confirms that the optimized antenna shows a minimum received power level above -60 dBm at a range of 200 km, which is similar to the pole antenna that is currently used as a FM voice antenna for KUH-Surion.

Ontology-based User Intention Recognition for Proactive Planning of Intelligent Robot Behavior (지능형로봇 행동의 능동적 계획수립을 위한 온톨로지 기반 사용자 의도인식)

  • Jeon, Ho-Cheol;Choi, Joong-Min
    • Journal of the Korean Institute of Intelligent Systems
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    • v.21 no.1
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    • pp.86-99
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    • 2011
  • Due to the uncertainty of intention recognition for behaviors of users, the intention is differently recognized according to the situation for the same behavior by the same user, the accuracy of user intention recognition by minimizing the uncertainty is able to be improved. This paper suggests a novel ontology-based method to recognize user intentions, and able to minimize the uncertainties that are the obstacles against the precise recognition of user intention. This approach creates ontology for user intention, makes a hierarchy and relationship among user intentions by using RuleML as well as Dynamic Bayesian Network, and improves the accuracy of user intention recognition by using the defined RuleML as well as the gathered sensor data such as temperature, humidity, vision, and auditory. To evaluate the performance of robot proactive planning mechanism, we developed a simulator, carried out some experiments to measure the accuracy of user intention recognition for all possible situations, and analyzed and detailed described the results. The result of our experiments represented relatively high level the accuracy of user intention recognition. On the other hand, the result of experiments tells us the fact that the actions including the uncertainty get in the way the precise user intention recognition.

AGV System Operating Scheme based on Grid Level Control in Automated Terminal (그리드 단위의 제어에 기반한 자동화 터미널의 AGV 시스템 운영 방안)

  • Lee, Yong-Hwan;Park, Eun-Kyung;Park, Tae-Jin;Ryu, Kwang-Ryel;Kim, Kap-Hwan
    • Journal of Navigation and Port Research
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    • v.27 no.2
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    • pp.223-231
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    • 2003
  • In this paper, we present a scheme for developing a simulator which verify the AGV system operation in automated container terminal. First of all, we propose a guide path in automated terminal considering AGV productivity and present a traffic control scheme in a such guide path. Generally, the AGV system can be controlled by zone control scheme, but there are no flexibility and use simple operation. In this paper, we propose and use grid based control scheme to improve the flexibility of the AGV movement. Lastly, we construct the simulation environment which can do similar to that of real task and ease the modification and improvement of the control logics.

Fault Detection Sensitivity of a Data-driven Empirical Model for the Nuclear Power Plant Instruments (데이터 기반 경험적 모델의 원전 계측기 고장검출 민감도 평가)

  • Hur, Seop;Kim, Jae-Hwan;Kim, Jung-Taek;Oh, In-Sock;Park, Jae-Chang;Kim, Chang-Hwoi
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.5
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    • pp.836-842
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    • 2016
  • When an accident occurs in the nuclear power plant, the faulted information might mislead to the high possibility of aggravating the accident. At the Fukushima accident, the operators misunderstood that there was no core exposure despite in the processing of core damage, because the instrument information of the reactor water level was provided to the operators optimistically other than the actual situation. Thus, this misunderstanding actually caused to much confusions on the rapid countermeasure on the accident, and then resulted in multiplying the accident propagation. It is necessary to be equipped with the function that informs operators the status of instrument integrity in real time. If plant operators verify that the instruments are working properly during accident conditions, they are able to make a decision more safely. In this study, we have performed various tests for the fault detection sensitivity of an data-driven empirical model to review the usability of the model in the accident conditions. The test was performed by using simulation data from the compact nuclear simulator that is numerically simulated to PWR type nuclear power plant. As a result of the test, the proposed model has shown good performance for detecting the specified instrument faults during normal plant conditions. Although the instrument fault detection sensitivity during plant accident conditions is lower than that during normal condition, the data-drive empirical model can be detected an instrument fault during early stage of plant accidents.

Synchronized One-to-many Media Streaming employing Server-Client Coordinated Adaptive Playout Control (적응형 재생제어를 이용한 동기화된 일대다 미디어 스트리밍)

  • Jo, Jin-Yong;Kim, Jong-Won
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.5C
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    • pp.493-505
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    • 2003
  • A new inter-client synchronization framework for multicast media streaming is proposed employing a server-client coordinated adaptive playout control. The proposed adaptive player controls the playback speed of audio and video by adopting the time-scale modification of audio. Based on the overall synchronization status as well as the buffer occupancy level, the playout speed of each client is manipulated within a perceptually tolerable range. Additionally, the server implicitly helps increasing the time available for retransmission while the clients perform an interactive error recovery mechanism with the assistance of playout control. The network-simulator based simulations show that the proposed framework can reduce the playout discontinuity without degrading the media quality, and thus mitigate the client heterogeneity.