• International Journal of Internet, Broadcasting and Communication
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• 제8권1호
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• pp.53-63
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• 2016

This paper applies WiMedia UWB network into a wireless ship area network (WSAN) so as to support high-quality multimedia services on board and reliable instrument control information as well, since the need for mixed high-quality video traffic and shipboard control data traffic is essential for a high-cost valued digital ship. Thus, in this paper, prioritized contention access (PCA) and distributed reservation protocol (DRP) based on WiMedia UWB (ECMA-368) MAC protocols are combined and proposed to such mixed traffic environment, by varying the portions of superframe according to traffic type. It is shown that the proposed WiMedia UWB MAC protocol can provide reliable mixed video and shipboard control data traffic as well.

• 한국인터넷방송통신학회논문지
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• 제12권5호
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• pp.61-66
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• 2012

본 논문은 운행중 차량에서 센싱된 교통정보를 차량간 ad-hoc 무선 통신망을 통하여 상호 전달하며, 그 중 3G망과 같은 인프라 네트워크와 연동이 가능한 극히 소수의 게이트웨이 차량이 있어 수집된 교통정보를 교통정보 서비스 센터의 서버로 전송하고 센터에서는 분석된 정보를 FM 라디오 주파수를 통해 방송하여 교통정보 서비스를 제공하는 시스템에 관하여 제안한다. 제안 시스템은 정보수집을 위한 별도의 도로 인프라 설비뿐만 아니라 별도의 교통정보 검지장치나 프로빙(Probing) 카를 이용하지 않고도 광범위한 지역의 교통상황에 대한 정보를 수집, 분석할 수 있으며 이를 토대로 정확하고 빠른 교통상황 정보를 각 운전자에게 제공할 수 있다. 본 논문에서 차량간 방송전파방식으로 무선채널로 운용하고 3G 또는 LTE 망과 같은 인프라구조 네트워크와 게이트웨이 시스템을 구현하고 ns-3로 성능을 분석한다.

• Journal of Communications and Networks
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• 제18권5호
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• pp.818-825
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• 2016

Network management and anomaly detection are challenges in high-speed networks due to the high volume of packets that has to be analysed. Flow-based analysis is a scalable method which reduces the high volume of network traffic by dividing it into flows. As sampling methods are extensively used in flow generators such as NetFlow, the impact of sampling on the performance of flow-based analysis needs to be investigated. Monitoring using sampled traffic is a well-studied research area, however, the impact of sampling on flow-based anomaly detection is a poorly researched area. This paper investigates flow sampling methods and shows that these methods have negative impact on flow-based anomaly detection. Therefore, we propose an efficient probabilistic flow sampling method that can preserve flow traffic distribution. The proposed sampling method takes into account two flow features: Destination IP address and octet. The destination IP addresses are sampled based on the number of received bytes. Our method provides efficient sampled traffic which has the required traffic features for both flow-based anomaly detection and monitoring. The proposed sampling method is evaluated using a number of generated flow-based datasets. The results show improvement in preserved malicious flows.

• 한국전자통신학회논문지
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• 제5권1호
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• pp.44-50
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• 2010

무선 센서 네트워크는 다수의 센서 노드로 구성되며, 센서 노드들의 협력 작업을 통해 하나의 공통 작업을 수행한다. WSN 의 트래픽은 주기적인 모니터링 트래픽, 이벤트 발생 트래픽 및 쿼리 기반 트래픽으로 분류된다. 주기적인 트래픽은 발생 빈도는 낮지만, 다수의 센서노드들이 일정한 간격으로 트래픽을 생성하기 때문에 전체 트래픽 관점에서 볼 때 많은 비중을 차지하고 있다. 본 논문에서는 이러한 주기적 트래픽에 대해 에너지 효율적으로 처리하는 네트워크 프로토콜의 트래픽 제어 알고리즘을 제안하고, 이에 대한 성능 분석을 수행한다.

• Journal of Communications and Networks
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• 제18권1호
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• pp.123-131
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• 2016

The high-availability seamless redundancy (HSR) protocol is one of the most important redundancy IEC standards that has garnered a great deal of attention because it offers a redundancy with zero recovery time, which is a feature that is required by most of the modern substation, smart grid, and industrial field applications. However, the HSR protocol consumes a lot of network bandwidth compared to the Ethernet standard. This is due to the duplication process for every sent frame in the HSR networks. In this paper, a novel algorithm known as the reducing multicast traffic (RMT) is presented to reduce the unnecessary redundant multicast traffic in HSR networks by limiting the spreading of the multicast traffic to only the rings that have members associated with that traffic instead of spreading the traffic into all the network parts, as occurs in the standard HSR protocol. The mathematical and the simulation analyses show that the RMT algorithm offers a traffic reduction percentage with a range of about 60-87% compared to the standard HSR protocol. Consequently, the RMT algorithm will increase the network performance by freeing more bandwidth so as to reduce HSR network congestion and also to minimize any intervention from the network administrator that would be required when using traditional traffic filtering techniques.

• Journal of Communications and Networks
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• 제6권3호
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• pp.269-279
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• 2004

A new online multi-layer integrated routing (MLIR) scheme that combines IP (electrical) layer routing with WDM (optical) layer routing is investigated. It is a highly efficient and cost-effective routing scheme viable for the next generation integrated optical Internet. A new simplified weighted graph model for the integrated optical Internet consisted of optical routers with multi-granularity optical-electrical hybrid switching capability is firstly proposed. Then, based on the proposed graph model, we develop an online integrated routing scheme called differentiated weighted fair algorithm (DWFA) employing adaptive admission control (routing) strategies with the motivation of service/bandwidth differentiation, which can jointly solve multi-layer routing problem by simply applying the minimal weighted path computation algorithm. The major objective of DWFA is fourfold: 1) Quality of service (QoS) routing for traffic requests with various priorities; 2) blocking fairness for traffic requests with various bandwidth granularities; 3) adaptive routing according to the policy parameters from service provider; 4) lower computational complexity. Simulation results show that DWFA performs better than traditional overlay routing schemes such as optical-first-routing (OFR) and electrical-first-routing (EFR), in terms of traffic blocking ratio, traffic blocking fairness, average traffic logical hop counts, and global network resource utilization. It has been proved that the DWFA is a simple, comprehensive, and practical scheme of integrated routing in optical Internet for service providers.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권4호
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• pp.269-276
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• 2013

Information and communication technology (ICT) is a promising solution for mitigating road traffic congestion. ICT allows road users and vehicles to be managed based on real-time road status information. In Tanzania, traffic congestion causes losses of TZS 655 billion per year. The main objective of this study was to develop an optimal approach for integrating real-time road information (RRI) to mitigate traffic congestion. Our research survey focused on three cities that are highly affected by traffic congestion, i.e., Arusha, Mwanza, and Dar es Salaam. The results showed that ICT is not yet utilized fully to solve road traffic congestion. Thus, we established a possible approach for Tanzania based on an analysis of road traffic data provided by organizations responsible for road traffic management and road users. Furthermore, we evaluated the available road information management techniques to test their suitability for use in Tanzania. Using the floating car data technique, fuzzy logic was implemented for real-time traffic level detection and decision making. Based on this solution, we propose a RRI system architecture, which considers the effective utilization of readily available communication technology in Tanzania.

• 한국정보전자통신기술학회논문지
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• 제11권6호
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• pp.751-756
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• 2018

본 연구는 입력 영상에서 교통 신호등을 검출하고, 신호등의 색상을 인식하며, 신호를 판별하여 무인 자율주행 차량이나 ITS(Intelligent Transportation System)에 적용할 수 있는 신호등 색상 인식 알고리즘을 제안하였다. 제안된 알고리즘은 교통신호등을 검출하기 위해 CEA(Canny Edge Algorithm)를 이용하여 외곽선을 추출하였고, 신호등의 색상을 인식하고 정확도를 높이기 위하여 HCT(Hough Circle Transform)를 적용하였다. 제안된 방법으로 주행도로상에서 획득한 스트림 영상에 적용한 결과, 우수한 신호등 색상 인식률을 확인할 수 있었다. 특히 입력영상에서 신호등이 존재할만한 ROI(Region Of Interest)로 구분하여 연산시간을 줄일 수 있었고, 신호등과 유사한 영역이라도 원이 검출되지 않거나 HSV 공간에서 V값이 낮아 후보영역에서 탈락시킴으로써 인식률의 정확도를 높일 수 있었다.

• 한국항행학회논문지
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• 제3권1호
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• pp.60-68
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• 1999

본 논문에서는 교통정보 수집용 영상검지기를 위한 새로운 배경생성 방법을 제안한다. 입력되는 영상열의 화소위치별 모든 밝기값을 평균 또는 빈도 계산과정에 참여시키는 기존의 배경생성방법은 차량의 정체가 잦은 경우에 좋지 않은 결과를 보인다. 이러한 단점을 개선하기 위해서 배경생성 과정에 하이레벨 정보인 차량의 탑지결과를 반영하였다. 차량으로 탐지되지 않은 영상부분만을 배경생성 과정에 참여시켰으며 실험을 통해서 새로 제안한 배경생성 방법이 종전 방법에 비해 차량의 정체가 잦은 경우에도 더 견고하게 차량 탐지를 할 수 있는 배경을 생성할 수 있었다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.476-481
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• 2009

In this paper, we propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as the transmitter, and on-vehicle high-speed camera as the receiver. The LEDs in the transmitter are emitted with 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. The images from the high-speed camera are processed to get luminance value of each LED in the transmitter. For this purpose, first transmitter should be found, then it should be tracked for each frame, and the luminance value of each LED in the transmitter should be captured. In our previous work, transmitter was found by getting the subtraction of two consecutive frames. In this paper, we mainly introduce an algorithm to detect the found transmitter in consecutive frames. Experimental results using appropriate images showed the effectiveness of the proposal