• Journal of Communications and Networks
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• 제8권4호
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• pp.432-441
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• 2006

As the community antenna television (CATV) networks becomes ubiquitous, instead of constructing an entirely new broadband network infrastructure, it has emerged as one of the rapid and economic technologies to interconnecting heterogeneous network to provide broadband access to subscribers. How to support ubiquitous real-time multimedia applications, especially in a heavy traffic environment, becomes a critical issue in modern CATV networks. In this paper, we propose a time guaranteed and efficient upstream minislots allocation algorithm for supporting quality-of-service (QoS) traffic over data over cable service interface specification (DOCSIS) CATV networks to fulfill the needs of realtime interactive services, such as video telephony, video on demand (VOD), distance learning, and so on. The proposed adaptive fast expansion algorithm and the loading statistics with dynamic swapping algorithm have been shown to perform better than that of the multimedia cable network system (MCNS) DOCSIS.

• 한국멀티미디어학회논문지
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• 제16권7호
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• pp.862-869
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• 2013

In order to support a cell-independent traffic asymmetry, the conventional TDD system cannot avoid crossed time slot (CTS) interference. Moreover, the TDD/FDD hierarchical overlay cellular systems is taken into account as a generally accepted cell model in a heterogeneous radio environment. In this paper, we propose an interference resolving radio resource allocation technique in a TDD-OFDMA cellular system that overlays a FDD-CDMA cell. In our proposed scheme, we exploit under-used FDD-CDMA uplink resource by TDD mobile abiding by a region based time slot(TS) allocation which in turn mitigates CTS interference considerably. It is demonstrated that combined with under-used resource utilization scheme based on mobile's location, the proposed technique can reduce CTS interference considerably and support the asymmetric traffic in TDD system.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 가을 학술발표논문집 Vol.34 No.2 (A)
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• pp.130-131
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• 2007

Wireless Sensor Network typically incorporates diverse applications within the same network. A sensor node may have multiple sensors i.e. light, temperature, seismic etc with different transmission characteristics. Each application has different characteristics and requirements in terms of transmission rates, bandwidth, packet loss and delay demands may be initiated towards the sink. In this paper we propose Heterogeneous Traffic Oriented Rate Control Protocol (HTRCP) which ensures efficient rate control for diverse applications according to the priority specified by the sink. Moreover. HTRCP ensures the node priority based hop by hop dynamic rate adjustment for high link utilization.

• ETRI Journal
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• 제28권3호
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• pp.311-319
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• 2006

This paper presents a terminal-assisted frame-based packet reservation multiple access (TAF-PRMA) protocol, which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA-based broadband access networks. In order to achieve a differentiated quality-of-service (QoS) guarantee for individual service plus maximal system resource utilization, TAF-PRMA independently controls the random access parameters such as the lengths of the access regions dedicated to respective service traffic and the corresponding permission probabilities, on a frame-by-frame basis. In addition, we have adopted a terminal-assisted random access mechanism where the voice terminal readjusts a global permission probability from the central controller in order to handle the 'fair access' issue resulting from distributed queuing problems inherent in the access network. Our extensive simulation results indicate that TAF-PRMA achieves significant improvements in terms of voice capacity, delay, and fairness over most of the existing medium access control (MAC) schemes for integrated services.

• International Journal of Computer Science & Network Security
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• 제21권3호
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• pp.1-10
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• 2021

In recent decades, the heterogeneous and dynamic behavior of Internet traffic has placed new demands on the adaptive resource allocation of the optical network infrastructure. However, the advent of multifiber elastic optical networks has led to a higher degree of spectrum fragmentation than conventional flexible grid networks due to the dynamic and random establishment and removal of optical connections. In this paper, we propose heuristic routing and dynamic slot allocation algorithms to minimize spectrum fragmentation and reduce the probability of blocking future connection requests by considering the power consumption in elastic multifiber elastic optical networks.

• 한국항행학회논문지
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• 제12권1호
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• pp.46-53
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• 2008

지능형 교통 체계(ITS: Intelligent Transport Systems)는 기존의 교통에 정보통신, 전기 및 전자, 기계, 제어 동의 기술을 접목시켜 도로 및 교통 체계의 안전 및 운영 효율을 극대화하여 교통 문제를 해결하는 시스템이다. 현재 대량의 교통 원시 데이터를 위해 시스템을 통합하는 문제는 다른 소스데이터 간의 표현상의 이질성 및 데이터의 양과 다양성 그리고 소스의 자동화와 서로 다른 성능 등 몇 가지 문제에 직면해 있다. 본 논문에서는 고속도로 교통관리시스템과 우회도로 교통정보시스템에서 수집되는 이질적인 대용량 교통데이터의 데이터웨어하우스를 구축하기 위해 상용 도구를 활용해 추출 및 적재하는 방안을 기술한다. 또한, 고품질 교통데이터를 제공하기 위한 통합 품질관리 기법을 적용하여 평가 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.178-202
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• 2012

In this paper, we first survey cross-layer architectures for Wireless Sensor Networks (WSNs) and Wireless Multimedia Sensor Networks (WMSNs). Afterwards, we propose a novel cross-layer architecture for QoS provisioning in clustered and multi-hop based WMSNs. The proposed architecture provides support for multiple network-based applications on a single sensor node. For supporting multiple applications on a single node, an area in memory is reserved where each application can store its network protocols settings. Furthermore, the proposed cross-layer architecture supports heterogeneous flows by classifying WMSN traffic into six traffic classes. The architecture incorporates a service differentiation module for QoS provisioning in WMSNs. The service differentiation module defines the forwarding behavior corresponding to each traffic class. The forwarding behavior is primarily determined by the priority of the traffic class, moreover the service differentiation module allocates bandwidth to each traffic class with goals to maximize network utilization and avoid starvation of low priority flows. The proposal incorporates the congestion detection and control algorithm. Upon detection of congestion, the congested node makes an estimate of the data rate that should be used by the node itself and its one-hop away upstream nodes. While estimating the data rate, the congested node considers the characteristics of different traffic classes along with their total bandwidth usage. The architecture uses a shared database to enable cross-layer interactions. Application's network protocol settings and the interaction with the shared database is done through a cross-layer optimization middleware.

• 대한토목학회논문집
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• 제29권4D호
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• pp.443-450
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• 2009

A연속류도로는 교통량-속도-밀도 간에 상호 밀접한 관계가 있기 때문에 연결로교통류가 본선에 합류하게 되면 속도나 밀도가 변할 뿐만 아니라 이들 간의 상관관계를 나타내는 모형식도 달라진다. 따라서, 본 연구는 합류영향권역에서 시공간적으로 연속된 교통자료를 이용하여 속도-밀도 변수간의 상관관계 변화구간을 파악하고, 구간별 변화내용을 분석하였다. 분석결과, 상류 및 합류구간에서는 "Underwood"모형의 지수형태를 보이며, 합류구간을 통과한 하류구간에서는 "Greenshields"모형의 직선형태를 나타내었다. 속도-밀도 상관관계가 변화된 하류변화구간은 연결로와 접속한 3차로의 합류 종점부를 기점으로 하류 100m~500m 범위에서 내측차로로 갈수록 점차 하류방향으로 이동하는 현상을 보였다. 또한, 상류구간, 합류구간, 하류변화구간은 속도-밀도 모형에서 자유속도(상수)와 혼잡밀도에 대한 자유속도비(기울기)가 통계적으로 서로 다른 이질적인 교통류로 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.4703-4723
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• 2018

In recent years, dense small cell network has been deployed to address the challenge that has resulted from the unprecendented growth of mobile data traffic and users. It has proven to be a cost efficeient solution to offload traffic from macro-cells. Software defined heterogeneous wireless network can decouple the control plane from the data plane. The control signal goes through the macro-cell while the data traffic can be offloaded by small cells. In this paper, we propose a framework for cell virtualization and user association in order to satisfy versatile requirements of multiple tenants. In the proposed framework, we propose an interference graph partioning based virtual-cell association and customized physical-cell association for multi-homed users in a software defined small cell network. The proposed user association scheme includes 3 steps: initialization, virtual-cell association and physical-cell association. Simulation results show that the proposed virtual-cell association outperforms the other schemes. For physical-cell association, the results on resource utilization and user fairness are examined for mobile users and infrastructure providers.

• 대한전자공학회논문지SD
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• 제48권9호
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• pp.40-49
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• 2011

다양한 컴포넌트의 집적과 저전력 정책에 대한 연구가 활발했던 시스템 온 칩 설계 분야에서는 최근 들어 집적되는 컴포넌트의 수가 늘어나고 특성이 다양해짐에 따라 이들의 인터커넥션 문제가 새로운 이슈로 주목받고 있다. 시스템 온 칩이 주목받기 시작한 이후로 컴포넌트들의 구성에 따른 성능을 평가하기 위한 각종 시뮬레이터의 개발이 진행되어 왔으며, 효율적인 컴포넌트간의 인터커넥션 설계를 위한 시뮬레이션 환경도 개발이 진행되어 이들을 이용한 성능 평가가 실제 설계에 반영되고 있다. 대부분의 시뮬레이션 환경은 시스템 온 칩의 성능을 테스트하는 데 있어서 수학적 확률 함수를 기반으로 한 트래픽을 사용하고 있으나, 이는 실제 칩의 동작을 테스트하기에는 한계가 있다. 따라서 실질적인 칩의 테스트를 위하여 시스템 상에서의 동작을 정확하게 모사할 수 있는 시뮬레이터의 필요성이 고조되고 있으나, 실제로 이러한 트래픽 생성 방법을 적용한 시뮬레이터는 전무한 실정이다. 이에 본 논문에서는 멀티 프로세서 시스템 온 칩 상에서 수학적 확률 모델은 물론 실제 시스템의 동작을 모사하는 시뮬레이션이 가능한 트래픽 생성 방법을 제안한다. 본 논문에서 제안된 트래픽 생성법은 실제 응용프로그램의 특성을 반영할 수 있도록 트래픽을 생성하므로 수학적 확률 함수를 이용한 트래픽 생성법보다 실제 동작에 가까운 시뮬레이션을 진행할 수 있으며 이는 인터커넥션에 따른 시스템의 성능을 실효적으로 비교할 수 있는 환경을 제공한다. 본 논문에서는 시뮬레이션을 통해 제안된 트래픽 생성법과 수학적 확률 함수를 이용한 트래픽 생성법의 차이를 비교하여 제안된 생성법의 이점에 대해 알아본다.