• Journal of Information Processing Systems
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• 제13권6호
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• pp.1544-1553
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• 2017

The network coding mechanism has attracted much attention because of its advantage of enhanced network throughput which is a desirable characteristic especially in a multi-hop wireless network with limited link capacity such as the device-to-device (D2D) communication network of 5G. COPE proposes to use the XOR-based network coding in the two-hop wireless network topology. For multi-hop wireless networks, the Distributed Coding-Aware Routing (DCAR) mechanism was proposed, in which the coding conditions for two flows intersecting at an intermediate node are defined and the routing metric to improve the coding opportunity by preferring those routes with longer queues is designed. Because the routes with longer queues may increase the delay, DCAR is inefficient in delivering real-time multimedia traffic flows. In this paper, we propose a network coding-aware routing protocol for multi-hop wireless networks that enhances DCAR by considering traffic load distribution and link quality. From this, we can achieve higher network throughput and lower end-to-end delay at the same time for the proper delivery of time-sensitive data flow. The Qualnet-based simulation results show that our proposed scheme outperforms DCAR in terms of throughput and delay.

• 한국도로학회논문집
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• 제18권1호
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• pp.1-11
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• 2016

PURPOSES : This study estimated the load effect of a single heavy truck to develop a live load model for the design and assessment of bridges located on an expressway with a limited truck entry weight. METHODS : The statistical estimation methods for the live load effect acting on a bridge by a heavy vehicle are reviewed, and applications using the actual measurement data for trucks traveling on an expressway are presented. The weight estimation of a single vehicle and its effect on a bridge are fundamental elements in the construction of a live load model. Two statistical estimation methods for the application of extrapolation in a probabilistic study and an additional estimation method that adopts the extreme value theory are reviewed. RESULTS : The proposed methods are applied to the traffic data measured on an expressway. All of the estimation methods yield similar results using the data measured when the weight limit has been relatively well observed because of the rigid enforcement of the weight regulation. On the other hand, when the estimations are made using overweight traffic data, the resulting values differ with the estimation method. CONCLUSIONS : The estimation methods based on the extreme distribution theory and the modified procedure presented in this paper can yield reasonable values for the maximum weight of a single truck, which can be applied in both the design and evaluation of a bridge on an expressway.

• 조명전기설비학회논문지
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• 제29권1호
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• pp.37-46
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• 2015

In order to charge EVs, they have to be connected to distribution system. Therefore, if unprecedented numbers of EVs are connected to power systems, it could result in deterioration of power quality, overload, and other system problems. In this paper, the effects of voltage sag on the distribution system due to the connection of EVs is evaluated by considering related field data of Republic of Korea such as the number of gasoline-fueled vehicles, seasonal load of power system and the monthly and daily real-time traffic volume. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP).

• 한국통신학회논문지
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• 제28권11B호
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• pp.1038-1049
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• 2003

트래픽 부하 측정은 네트웍 트래픽 엔지니어링의 기반이 된다. 그러나 고속 링크에서 트래픽 부하 정보를 얻기 위해 모든 패킷을 측정하는 것은, 라우터의 패킷 포워딩 성능을 저해시키므로 확장성이 결여된다. 이에 따라 샘플링 기법이 트래픽 측정의 대안으로 제시되었다. 샘플링은 라우터의 성능 저해를 최소화시킬 수 있으나 샘플링으로 예측되는 트래픽 부하는 실제 트래픽 부하와 차이를 보이게 되며, 이와 같은 오류가 제한되지 못한다면 측정값을 기반으로 하는 응용들에 부영향을 미치게 된다. 본 논문에서는 샘플링 오류를 오류 허용범위 내로 제한시킬 수 있는 적응성 있는 패킷 샘플링 기법을 제안한다. 제안 기법은 수학적 분석을 통해 얻어진 부하 예측 오류에 영향을 미치는 주요 트래픽 파라메터를 각 블록의 시작마다 예측하여 샘플링 확률을 동적으로 적응시킨다. 본 논문에서는 또한 실제 측정된 인터넷 트래픽을 이용하여 제안 기법의 확장성과 성능을 검증하였다

• 한국통신학회논문지
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• 제28권1A호
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• pp.1-6
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• 2003

We propose a mathematical model to analyze the performance of TD-CDMA/TDD systems in terms of call blocking probability and then find the optimum time-slot switching-point at the smallest call blocking probability considering asymmetrical traffic load distribution for various kinds of service applications.

• Steel and Composite Structures
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• 제2권1호
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• pp.67-84
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• 2002

Traffic decks of steel or composite motorway bridges sometimes provide the opportunity of using the composite action between an existing steel deck and a reinforced concrete plate (RC plate) in the process of rehabilitation, i.e., to increase the load-carrying capacity of the deck for concentrated traffic loads. The steel decks may be orthotropic decks or also unstiffened steel plates, which during the rehabilitation are connected with the RC plate by shear studs, such developing an improved local load distribution by the joint behaviour of the two plate elements. Investigations carried out, both experimentally and numerically, were performed in order to quantitatively assess the combined static behaviour and to qualitatively verify the usability of the structure for dynamic loading. The paper reports on the testing, the numerical simulation as well as the comparison of the results. Conclusions drawn for practical design indicated that the static behaviour of these structures may be very efficient and can also be analysed numerically. Further, the results gave evidence of a highly robust behaviour under fatigue equivalent cyclic traffic loading.

• 한국정보통신학회논문지
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• 제9권6호
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• pp.1387-1394
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• 2005

본 논문에서는 다중 셀룰러 CDMA 환경에서 비균일 트래픽 특성을 가진 지능정보 처리를 위한 호 수락제어 기법을 제안하고, 이 기법의 성능을 분석한다. CDMA 시스템에서는 각 셀에서 동시에 통화할 수 있는 이동 가입자들의 수는 각 기지국이 수신하는 총 간섭량에 따라 제약을 받고, 또한 서비스 받는 이동 가입자의 수는 각 기지국마다 균일하지 않게 분포될 수 있다. 본 논문에서는 이러한 환경에서 비균일 트래픽 특성의 지능정보 처리용량을 높이기 위해 등가대역 개념을 이용한 호 수락 제어 기법을 사용하며, 신규 호의 차단율(blocking rate) 및 핸드오프 호의 절단율(dropping rate)을 감소시키기 위해 각 셀의 대역폭을 가변시켜 신규 호와 핸드오프 호를 처리한다. 실험결과 다중 셀룰러 CDMA 환경에 제안한 호 제어 기법을 적용함으로써 이동 가입자의 수용 용량을 증가시킬 수 있음을 확인하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.269-273
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• 2004

This paper presents a comparative performance analysis of a network accelerator model based on M/M/l queuing system. It assumes the Poisson distribution as its input traffic load. The decoding delay is employed as a performance analysis measure. Simulation results based on the proposed model show only $15\%$ differences with respect to actual measurements on field traffic for BCM5820 accelerator device. The performance analysis model provides with reasonable hardware structure of network servers, and can be used to span design spaces statistically.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• 정보보호학회논문지
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• 제14권4호
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• pp.141-148
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• 2004

본 논문에서는 IPSec 가속기의 성능분석 모델을 제안한다. 제안된 성능분석은 큐잉 모델링을 기반으로 하고 트래픽로드는 포아송 분포를 채택하였다. 성능분석 시 새로운 파라미터로 디코딩지연을 정의하여 시뮬레이션에 이용하였다. 제안된 모델을 이용하여 IPSec 가속장치인 BCM5820의 성능을 분석한 결과, 장비를 통해 실측된 결과와 15% 정도의 차이만을 나타내었다. 제안된 모델을 이용한 성능분석 결과는 IPSec 가속기의 최대성능을 유지하기 위한 서버내의 하드웨어들의 적합한 구조를 제시하고 나아가 고속 네트워크 컴퓨터의 통계적 설계공간탐색에 이용될 수 있다.