• Title/Summary/Keyword: congestion management

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Improvement and Comparative Study of Control Theory-based AQM Methods for Networks with Realistic Traffic

  • Bigdeli, N.;Haeri, M.;Pakravan, M.R.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.767-771
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    • 2004
  • In this paper the performance of some control theory-based Active Queue Management (AQM) methods are improved and investigated through simulation. The simulation scenario is considered to be closely realistic, in which the traffic is mainly due to http sessions. The results show the best performance of PID controller with respect to the others in good queue regulation as well as high link utilization and low delay metrics.

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Incidental finding of an extensive oropharyngeal mass in magnetic resonance imaging of a patient with temporomandibular disorder: A case report

  • Omolehinwa, Temitope T.;Mupparapu, Mel;Akintoye, Sunday O.
    • Imaging Science in Dentistry
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    • v.46 no.4
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    • pp.285-290
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    • 2016
  • In this report, we describe the incidental finding of an oropharyngeal mass in a patient who presented with a chief complaint of temporomandibular pain. The patient was initially evaluated by an otorhinolaryngologist for complaints of headaches, earache, and sinus congestion. Due to worsening headaches and trismus, he was further referred for the management of temporomandibular disorder. The clinical evaluation was uneventful except for limited mouth opening (trismus). An advanced radiological evaluation using magnetic resonance imaging revealed a mass in the nasopharyngeal/oropharyngeal region. The mass occupied the masticatory space and extended superioinferiorly from the skull base to the mandible. A diagnostic biopsy of the lesion revealed a long­standing human papilloma virus (HPV­16)­positive squamous cell carcinoma of the oropharynx. This case illustrates the need for the timely radiological evaluation of seemingly innocuous orofacial pain.

Traffic Flow Analysis Methodology Using the Discrete Event Modeling and Simulation (이산 사건 모델링 및 시뮬레이션을 이용한 교통 흐름 분석 방법론)

  • 이자옥;지승도
    • Journal of Korean Society of Transportation
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    • v.14 no.1
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    • pp.101-116
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    • 1996
  • Increased attention has been paid in recent years to the need of traffic management for alleviating urban traffic congestion. This paper presents a discrete event modeling and simulation framework for analyzing the traffic flow. Traffic simulation models can be classified as being either microscopic and macroscopic models. The discrete event modeling and simulation technique can be basically employed to describe the macroscopic traffic simulation model. To do this, we have employed the System Entity Structure/Model Base (SES/MB) framework which integrates the dynamic-based formalism of simulation with the symbolic formalism of AI. The SES/MB framework supports to hierarchical, modular discrete event modeling and simulation environment. We also adopt the Symbolic DEVS (Discrete Event System Specification) to developed the automated analysis methodology for generating optimal signal light policy. Several simulation tests will demonstrates the techniques.

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An Optimal Incentive-Compatible Pricing for Congestible Networks (혼잡이 있는 네트워크를 위한 동기 유발 가격)

  • Kim, Yong-Jae
    • Asia pacific journal of information systems
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    • v.7 no.3
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    • pp.109-124
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    • 1997
  • Pricing information services, where congestion can threaten the efficient operation of information systems, has been studied in economics and information systems literature, Recent explosion of the Internet ana proliferation of multimedia content over the Internet have rekindled the research interest in designing pricing schedules for differentiated information services, In order for the information system to effectively serve users having heterogeneous needs, pricing rules for discriminated services should be considered. At the same time, when individual users' interest does not align with that of the organization that individual users belong to, organization-wide pricing policy should be devised to improve the value of the services rendered by the system. This paper, using a priority queuing model, addresses the need for such on incentive-compatible pricing for different information services.

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Acute Respiratory Insufficiency Following Blunt Chest Trauma -2 Case Report- (흉부손상에 병발한 급성호흡부전증 -2예 보고-)

  • Wang, Young Pil;Lee, Hong Kyun
    • Journal of Chest Surgery
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    • v.9 no.2
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    • pp.148-156
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    • 1976
  • Acute respiratory failure has become an increasingly frequent cause of death following shock or trauma. Interstitial or diffuse alveolar edema, as chief pathophysiologic change of acute respiratory insufficiency, can be the result of sepsis, fat embolism, cardiac failure, lung congestion, and oxygen toxicity. These pulmonary problems are extremely difficult to treat without early recognition of their development and aggressive management. If the treatment is delayed, the progressive respiratory failure is almost uniformly fatal. Authors have experienced two cases of acute respiratory insufficiency following the blunt chest trauma, which were healed uneventfully. Literatures were briefly reviewed.

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Initial Investigation on Consolidation with Adaptive Dynamic Threshold for ABR Multicast Connections in ATM Networks (비동기 전송모드 망의 점대다중점연결을 위한 적응동적임계치기반 병합알고리즘)

  • Shin, Soung-Wook;Cho, Kwang-Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.11
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    • pp.962-966
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    • 2001
  • The major problem at a branch point for point-to-multipoint available bit rate(ABR) services in asynchronous transfer mode (ATM) networks is how to consolidate backward resource management(BRM) cells from each branch for a multicast connection. In this paper, we propose an efficient feedback consolidation algorithm based on an adaptive dynamic threshold(ADT) to eliminate the consolidation noise and the reduce the consolidation delay. The main idea of the ADT algorithm lies in that each branch point estimates the ABR traffic condition of the network through the virtual queue estimation and the transmission threshold of the queue level in branch points is adaptively controlled according to the estimation. Simulation results show that the proposed ADT algorithm can achieve a faster response in congestion status and a higher link utilization compared with the previous works.

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An Efficient Multicast Algorithm for ATM Networks (ATM 망을 위한 효과적인 멀티캐스트 알고리즘)

  • 천상훈;곽경섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.6B
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    • pp.1108-1112
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    • 1999
  • In this paper, we propose an efficient ABR multicast algorithm for ATM networks. In ABR multicast algorithim, the feedback consolidation is necessary to avoid excessive backward resource management (BRM) cells and to aggregate the information from BRM cells received from each branch. The proposed scheme is shown to achieve fast transient response to the congestion status on a branch as well as effectively eliminate the consolidation noise through system simulation.

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INVESTIGATION OF MARINE TRAFFIC IN THE ADJACENT OF SAIGON - VUNGTAU FAIRWAY TO MANAGE MARINE SAFETY

  • Thanh, Nguyen Xuan;Park, Young-Soo;Park, Jin-Soo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2012.06a
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    • pp.52-54
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    • 2012
  • Saigon-Vungtau fairway is the main and the most important fairway of the major economic areas: Ho Chi Minh City, Dong Nai Province and Ba Ria-Vung Tau Province in Vietnam. In last 5 years, 80% of accidents happened on the fairway were caused by collision and contact/impact. This presentation study on marine traffic investigation in the adjacent of the fairway to find out problems related to marine traffic for improving Marine Traffic Safety Management in this area.

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Information Exchange Protocol Design for Decentralized Congestion Management (분권화 된 송전선로 혼잡관리를 위한 정보공유 프로토콜 개발)

  • Jeong, Jae-Woo;Song, Sung-Hwan;Yoon, Yong-Tae;Moon, Seung-Il
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.386-387
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    • 2006
  • 전력시스템은 기존에 수직통합체제에서 벗어나 시장이라는 운영체제로 발전되고 있다. 이는 시스템의 불안정한 요소를 증가시키고 있으며, 이에 따라 시장체제 하에서 송전선로의 혼잡관리는 시스템을 안정적으로 운영될 수 있게 하는 중요한 요소 중의 하나로 간주되고 있다. 현재 사용되고 있는 최적조류계산(OPF) 방법은 송전선로 혼잡을 직접적으로 해결할 수 있는 방법이지만, 그 계산에 있어 시장 참여자들의 세부적인 정보의 공개를 요구하기 때문에 경쟁 시장체제에는 적당한 방법이 아니다. 따라서 본 논문에서는 시장 체제에 적합토록 제한된 정보 하에서 분권화 된 계산을 통한 혼잡관리 방식과 이에 따라 필요한 정보공유 프로토콜을 제안하겠다. 제안된 방법은 간단한 3모선 시뮬레이션을 통해 검증토록 하겠다.

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Grounding Resistance Measurement and Analysis of Building Structures for Applying as Safety Earthing (보호접지로 활용하기 위한 건축물 구조체의 접지저항 측정분석)

  • Oh, Se-Jung;Kim, Chan-O
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.8
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    • pp.50-55
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    • 2012
  • Grounding is very important for electrical safety. But it is very difficult to secure enough space for the installation and management of grounding in the city because of the congestion of the buildings. Therefore, to solve this problem, this paper suggest structure-grounding application taking advantage of building structure as protective grounding. And, to verify its feasibility, this paper shows the result to measure and analyze grounding-resistance of structure for 12 buildings mainly structed in the city.