• 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.

• 한국컴퓨터정보학회논문지
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• 제4권4호
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• pp.140-147
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• 1999

ABR(Available Bit Rate) 서비스는 ATM(Asynchronous Transfer Mode)망에서 guranteed 서비스에 의해 사용되고 있지 않는 여분의망 자원을 보다 효율적으로 사용키 위해 최대 전송률이 높고 burst한 특성을 지닌 응용들을 best effort 형태로 지원해주는 서비스이다. ATM 망에서 ABR 흐름제어를 위해 사용되는 스위치는 폭주상태 정보만 제공하는 EFCI(Explicit Forward Congestion Indication)스위치와 fair rate를 source에게 제공하는 ER(Explicit Rate)스위치로 구분할 수 있다. 본 논문에서는 ATM망에서 ABR 서비스를 위하여 EFCI 스위치와 ER 스위치가 ATM망에서 혼용되어 사용될 경우 ABR트래픽을 효율적으로 처리하기 위한 스위칭운용기술에 대해서 분석하였다.

• 한국경영과학회지
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• 제32권3호
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• pp.63-80
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• 2007

This study is a generalization of 'stable dynamics' recently suggested by Nesterov and de Palma[29]. Stable dynamics is a new model which describes and provides a stable state of congestion in urban transportation networks. In comparison with user equilibrium model that is common in analyzing transportation networks, stable dynamics requires few parameters and is coincident with intuitions and observations on the congestion. Therefore it is expected to be an useful analysis tool for transportation planners. An equilibrium in stable dynamics needs only maximum flow in each arc and Wardrop[33] Principle. In this study, we generalize the stable dynamics into the model with multiple traffic classes. We classify the traffic into the types of vehicle such as cars, buses and trucks. Driving behaviors classified by age, sex and income-level can also be classes. We develop an equilibrium with multiple traffic classes. We can find the equilibrium by solving the well-known network problem, multicommodity minimum cost network flow problem.

• 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.

• 한국멀티미디어학회논문지
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• 제11권12호
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• pp.1716-1721
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• 2008

Currently, Wireless Networks have some nice characteristics such as multi-hop, multi-channel, multi-radio, etc but these kinds of resources are not fully used. The most difficulty to solve this issue is to solve mixed integer optimization. This paper proposes a method to solve a class of mixed integer optimization for wireless networks by using AMPL modeling language with CPLEX solver. The result of method is scheduling and congestion control in multi-channel multi-radio wireless networks.

• International Journal of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.1-7
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• 2023

TCP is considered a major candidate transport protocol even for constrained IoT networks due to its ability to integrate into the existing network infrastructures. Since TCP implementations such as uIP TCP often allow only a single TCP segment per connection to be unacknowledged at any given time due to resource constraints, the congestion control relies only on RTO management. In our previous work, to address the problem that uIP TCP performs poorly particularly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe, we proposed a RTO scheme for uIP TCP and validated the performance through Cooja simulation. In this study, we investigate the effect of other factors that were not considered in our previous work. More specifically, the effect of traffic intensity, the degree of the hidden terminal problem, and RDC is investigated by varying the offered load and the transmission range, and the RDC channel check rate. Simulation results imply that we need to further investigate how to improve TCP performance when the radio duty cycling mechanism is used.

• 한국재난정보학회:학술대회논문집
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• 한국재난정보학회 2023년 정기학술대회 논문집
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• pp.259-260
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• 2023

The rapid urbanization and modernization observed in countries like Myanmar have led to significant concerns regarding traffic congestion, especially in urban areas. This study focuses on the analysis and revitalization of urban transport in selected areas of Myanmar. The core of urban transportation planning lies in travel forecasting, which employs models to predict future traffic patterns and guide decisions related to road capacity, transit services, and land use policies. Travel demand modeling involves a series of mathematical models that simulate traveler behavior and decision-making within a transportation system, including highways, transit options, and policies. The paper offers an overview of the traditional four-step transportation modeling system, utilizing a simplified transport network in the context of Mandalay City, Myanmar.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1758-1763
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• 2004

This paper focuses on congestion control for ATM network with uncertain time-variant delays. The time-variant delays can be distinguished into two distinct components. The first one is represented by time-variant queueing delays in the intermediate switches that are occurred in the return paths of RM cells. The next one is a forward path delay. It is solved by the VBR model which quantifies the data propagation from the sources to the switch. Robust $H_8$ control is studied for solving congestion problem with norm-bounded time-varying uncertain parameters. The suitable robust $H_8$ controller is obtained from the solution of a convex optimization problem through LMI technique.

• 대한교통학회지
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• 제14권3호
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• pp.27-44
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• 1996

The purpose of the thesis is providing a new formulation for the transit assignment problem. The existing models dealing with the transit assignment problem don't consider the congestion effects due to the insufficient capacity of transit vehicles. Besides, these models don't provide solutions satisfying the Wardrop's user equilibrium conditions. The congestion effects are considered to be concentrated at the transit stops. For the transit lines, the waiting times at the transit stops are dependent on the passenger flows. The new model suggests the route section cost function analogous to the link performance function of the auto assignment to reflect the congestion effects in congested transit network. With the asymmetric cost function, the variational inequality programming is used to obtain the solutions satisfying Wardrop's condition. The diagonalization algorithm is introduced to solve this model. Finally, the results are compared with those of EMME/2.

• 한국통신학회논문지
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• 제33권9B호
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• pp.767-774
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• 2008

유비쿼터스 센서 네트워크 기술의 발전과 더불어 모바일 노드들 간의 통신에 대한 요구가 증가하고 있다. 기존 TCP를 MANET에 적용하였을 때, 링크의 단절, 경과의 재설정 및 네트워크 파티션 현상이 TCP로 하여금 혼잡으로 인식하게 한다. 그 결과, TCP는 성능저하를 보인다. 본 논문에서는 크로스레이어 디자인을 이용하여 MANET에 적합한 TCP를 설계하고 ns2로 분석하였다.