• 제어로봇시스템학회논문지
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• 제5권8호
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• pp.907-913
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• 1999

For an automated transportation system like PRT(Personal Rapid Transit) system or IVHS, an efficient vehicle-merging algorithm is required for smooth operation of the network. For management of merging, collision avoidance between vehicles, ride comfort, and the effect on traffic should be considered. This paper proposes an unmanned vehicle-merging algorithm that consists of two procedures. First, a longitudinal control algorithm is designed to keep a safe headway between vehicles in a single lane. Secondly, 'vacant slot and ghost vehicle' concept is introduced and a decision algorithm is designed to determine the sequence of vehicles entering a converging section considering energy consumption, ride comfort, and total traffic flow. The sequencing algorithm is based on fuzzy rules and the membership functions are determined first by an intuitive method and then trained by a learning method using a neural network. The vehicle-merging algorithm is shown to be effective through simulations based on a PRT model.

• 전기전자학회논문지
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• 제5권1호
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• pp.35-42
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• 2001

This paper deals with an architecture of network-based control system using the CAN(Controller Area Network) protocol and its traffic analysis. It is difficult to determine an optimal network-based control architecture for a specific AGV(Autonomous Guided Vehicle) system with a manipulator arm. The fixed number of periodic messages to be occurred is pre-defined in the system. To determine whether the proposed system architecture is effective or not, we perform traffic analysis for the real-time communication of all messages. Through simulations, the range of transmission speed is found satisfying required conditions and the permissible number of additional sensors is investigated for improving the system performance, when the sampling periods of analog sensors are determined under fixed condition that the transmission speed is over 500Kbps.

• 한국통신학회논문지
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• 제25권9A호
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• pp.1299-1305
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• 2000

도래할 B-ISDN 환경하에서 중추적 역할을 할 ATM의 실현을 위해서는 다중매체의 통화유량을 최적하에 제어할 수 있는 방법이 제시되어야 한다. 그러나 다중매체 통화유량의 특성이 완전히 밝혀지지 못한 상태에서 ATM의 제어, 특히 최적한 폭주제어의 실현은 난제로 남아있다. 그러므로 본 논문에서는 다중매체 통화유량 모델을 시변비선형함수라 가정하고 이를 실시간 추정하기 위해 병렬로 연결된 3중의 신경망 모델을 제시하며 모의실험을 통해 시변비선형함수를 추정하여 ATM의 폭주제어에 이용될 수 있는 가능성을 보인다.

• 인터넷정보학회논문지
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• 제4권2호
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• pp.39-45
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• 2003

네트워크에서 QoS를 지원하기 위한 적응제어 구조를 개발하기 위해서는 대역폭 할당에 따른 전송율 응답특성을 모델링하는 것이 필수적이다. 본 연구에서는 네트워크의 대역폭 할당에 따른 전송율의 동적 특성을 구현하는 "동적 시스템 모델"을 제안하고 적응 피드백 제어 구조를 제안된 모델에 적용시켜 시뮬레이션 및 모델의 최적화를 수행하였다.적화를 수행하였다.

• Journal of Communications and Networks
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• 제14권3호
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• pp.310-318
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• 2012

Detecting intrusion attacks accurately and rapidly in wireless networks is one of the most challenging security problems. Intrusion attacks of various types can be detected by the change in traffic flow that they induce. Wireless industrial networks based on the wireless networks for industrial automation-process automation (WIA-PA) standard use a superframe to schedule network communications. We propose an intrusion detection system for WIA-PA networks. After modeling and analyzing traffic flow data by time-sequence techniques, we propose a data traffic prediction model based on autoregressive moving average (ARMA) using the time series data. The model can quickly and precisely predict network traffic. We initialized the model with data traffic measurements taken by a 16-channel analyzer. Test results show that our scheme can effectively detect intrusion attacks, improve the overall network performance, and prolong the network lifetime.

• 한국통신학회논문지
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• 제19권2호
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• pp.354-363
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• 1994

본 논문은 광대역 ISDN에서 음성 서비스를 효율적으로 제공하는 방법에 관한 연구이다. 음성은 그 특성상 유음구간과 북음구간으로 나누어지며, 음성활성검출에 의하여 실제로 말을 하는 동안만 전송이 이루어질 수 있도록 음성 트래픽을 발생한다. 본 논문에서는 ATM통신망에서 음성을 음성활성검출과 삽입(Embedded) ADPCM으로 코딩하고, 멀티플렉서에서 셀 폐기를 통하여 트래픽을 제어하는 알고리즘에 관하여 연구하였다. 트래픽 제어는 버퍼에 임계값을 주어, 버퍼의 상태가 임계값을 초과하는 경우에 낮은 우선순위를 갖는 음성 셀을 폐기하는 셀 폐기 알고리즘을 사용하였다. 셀 손실 확률, 큐 크기, 평균지연등을 성능분석 파라메터로 설정하고, 트래픽 제어 알고리즘의 성능을 평가하기 위하여 컴퓨터 시뮬레이션하였다. 이를 통하여 센 폐기방식에 의한 트래픽 제어가 음성의 질을 많이 저하시키지 않으면서도 트래픽 제어를 하지 않을 때에 비하여 전송 대역 이득을 향상시킨다는 것을 확인하였다.

• 제어로봇시스템학회논문지
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• 제13권4호
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• pp.352-357
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• 2007

This paper deals with modeling method and application of Fuzzy Discrete Event System(FDES). FDES have characteristics which Crisp Discrete Event System(CDES) can't deals with and is constituted with the events that is determined by vague and uncertain judgement like biomedical or traffic control. We proposed Real-time Fuzzy Temporal Logic Framework(RFTLF) to model Fuzzy Discrete Event System. It combines Temporal Logic Framework with Fuzzy Theory. We represented the model of traffic signal systems for intersection to have the property of Fuzzy Discrete Event System with Real-time Fuzzy Temporal Logic Framework and designed a traffic signal controller for smooth traffic flow. Moreover, we proposed the method to find the minimum-time route to reach the desired destination with information obtained in each intersection. In order to evaluate the performance of Real-time Fuzzy Temporal Logic Framework model proposed in this paper, we simulated unit-time extension traffic signal controller model of the latest signal control method on the same condition.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.294-297
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• 2006

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• 한국통신학회논문지
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• 제29권7B호
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• pp.641-649
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• 2004

홈 네트워크에서 다양한 응용(application) 트래픽(traffic) 간의 차등화 된 서비스를 제공하기 위해서 트래픽 변화에 따라 적응적으로 우선순위(priority)를 재할당하는 알고리즘을 제안하고, FPGA를 이용하여 구현하였다. 제안된 구조는 QoS를 위한 부가적인 시그널링 프로토콜이 없이도 네트워크 트래픽 조절이 가능하도록 설계되었고, 또한 홈 네트워크 트래픽을 그 특징에 따라 제어 데이터 트래픽, 일반 인터넷이나 데이터 트래픽, 그리고 멀티미디어 데이터 트래픽으로 분류하고 이를 네트워크 트래픽 상황에 적응적으로 차등화 서비스를 제공할 수 있도록 설계되었다. 시뮬레이션을 통하여 제시한 알고리즘의 성능을 검증하고 FPGA구현을 통하여 실현가능성을 제시하였다.

• 한국군사과학기술학회지
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• 제22권3호
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• pp.369-381
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• 2019

As tactical networks are gradually shifting toward IP-based flexible operation for diversified battlefield services, QoS(Quality-of-Service) coordination for service differentiation becomes essential to overcome the heterogeneous and scarce networking resources limitations. QoS coordination for tactical network traffic should be able to monitor and react the dynamic changes in underlying network topology and service priorities. In this paper, by adopting the emerging cloud-native service mesh concept into tactical network context, we study the feasibility of intelligent QoS coordination by employing tactical service mesh(TSM) as an additional layer to support enhanced traffic quality monitoring and control. The additional TSM layer can leverage distributed service-mesh proxies at tactical mesh WAN(Wide Area Network) nodes so that service-aware differentiated QoS coordination can be effectively designed and integrated with TSM-assisted traffic monitoring and control. Also, by validating the feasibility of TSM layer for QoS coordination with miniaturized experimental setup, we show the potential of the proposed approach with several approximated battlefield traffics over a simulated TSM-enabled tactical network.