• Title, Summary, Keyword: UPC

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UPC Schemes on the Frame Relay/ATM Interworking in ATM Networks (FR/ATM 연동에서의 UPC 방식)

  • Nam, Yun-Seok;Park, Won-Sik
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.11
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    • pp.3108-3115
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    • 1999
  • Frame relay needs UPC function for the multiplexed logical connections to prevent malicious user traffic from incoming to network, to guarantee the QoS of conformed user traffic, and to protect the normal operation of network system. On the FR/ATM interworking in ATM networks, the UPC may be conducted either by cell-based ATM UPC or frame-based FR UPC. Frames come into and traverse ATm networks by segmentation to ATM cells. Of course, FR QoS should be guaranteed in spite of segmentation and reassembly in ATM networks. In this paper, we compared the QoS of cell-based ATM UPC and frame-based FR UPC in terms of analysis and simulation in case of ingress of excess traffic over negotiated traffic parameters at user-to-network interface. Also we studied frame-based UPC schemes including window-based FR UPC and frame-based VSA which is an ATM UPC algorithm recommended by ITU-T. We described introductions to frame relay including frame structure and FR/ATM interworking, FR traffic parameters and their relationship, comparison of FR QoS between frame-based FR UPC and cell-based ATM UPC, comparison of FR UPC schemes, necessities of egress traffic control, and conclusions.

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An Effective Hybrid UPC Algorithm for the Traffic Control of ATM Networks (ATM 망의 트래픽 제어를 위한 효율적인 하이브리드 UPC 알고리즘)

  • 윤석현
    • Journal of the Korea Society of Computer and Information
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    • v.5 no.3
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    • pp.112-118
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    • 2000
  • In this paper, a hybrid UPC algorithm is proposed, which combines the representative Leaky Bucket UPC algorithm with the EWMA window algorithm in the ATM network and then its performance Is evaluated. The hybrid UPC algorithm is made up of Leaky Bucket and EWMA, which control the Peak bit rate and the mean bit rate, respectively. According to the result of the simulation using BONeS with the On/off traffic source model. it is revealed that the proposed UPC algorithm has superior performance to the existing Leaky Bucket UPC algorithm with regard to both the cell loss rate and the buffer size.

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UPC 방식 분석

  • Sin, Seong-Mun;Lee, Jong-Hyeop;Choe, Mun-Gi
    • ETRI Journal
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    • v.14 no.4
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    • pp.258-270
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    • 1992
  • It is indispensable to control the service traffic for maximizing the advantages of ATM. This paper introduces the scheme of the an ATM traffic control and investigates the UPC(Usage Parameter Control) algorithms of the ATM-traffic. We have extracted the considerations on UPC algorithms and described the definition of the performance. We also have searched the way to choose the most appropriate UPC method considering the UPC's environments. As a result, we proposed the reliable UPC method that is applicable to B-ISDN, based on the comparison of the performance and the implementation of each.

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Computational modeling of cracking of concrete in strong discontinuity settings

  • Oliver, J.;Huespe, A.;Pulido, M.D.G.;Blanco, S.
    • Computers and Concrete
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    • v.1 no.1
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    • pp.61-76
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    • 2004
  • The paper is devoted to present the Continuum Strong Discontinuity Approach (CSDA) and to examine its capabilities for modeling cracking of concrete. After introducing the main ingredients of the CSDA, an isotropic continuum damage model, which distinguishes tension and compression states, is used to implicitly induce a projected traction separation-law that rules the cracking phenomena. Criteria for onset and propagation of material failure and specific finite elements with embedded discontinuities are also briefly sketched. Finally, some representative numerical simulations of cracking, in plain and reinforced concrete specimens, using the CSDA are presented.

Strategy for An Adaptive UPC Algorithm with Buffer Threshold in ATM Network (버퍼 지연을 고려한 ATM 망의 적응적 UPC 알고리즘의 기법)

  • An, Ok-Jeong;Chae, Gi-Jun
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.1
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    • pp.224-236
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    • 1997
  • In order to control the flow of traffic in ATM networks and optimize the usage of network resources, an appropriate control mechanism is necessary to cope with congestion or prevent degradation of network performance caused by congestion. While the conventional UPC algorithm provides only unstable preventive function unrelated with the state of networks and is unable to recover congestion, the proposed adaptive UPC algorithm supervises the situation of ATM networks using the information from OAM cell. Then the monitor of the proposed adaptive UPC algorithm controls leaky rate and buffer threshold value according to QOS. Therefore, the proposed algorithm can cope with congestion as well as prevent and react sensitively to buffer delay. In proportion to the diversity of traffic and the increase of transmission rate in networks, the adaptive UPC-BT algorithm proposed in this paper can be effectively used in ATM networks with wide applications. This paper shows that the proposed algorithm efficiently uses in ATM networks with application. This paper shows that the proposed algorithm efficiently use network resources and provides QOS to users for various kinds of traffics by comparing with conventional UPC algorithms.

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Implementation of UPC algorithm in ATM network (ATM망에서의 UPC 알고리즘 구현)

  • 이요섭;조태경;최명렬
    • Proceedings of the Korean Information Science Society Conference
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    • pp.88-90
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    • 2002
  • 본 논문에서는 ATM 망의 트래픽 제어 기능 중의 하나인 UPC(Usage Parameter Control) 알고리즘을 제안하고 VHDL을 이용하여 칩(chip)을 구현하였다. 제안한 알고리즘은 우선순위가 높은 셀의 손실을 최소로 하고, 트래픽의 다중화 및 역다중화 과정에서 발생되는 트래픽의 군집성을 해소할 수 있다는 장점을 갖고 있다. 구현한 칩은 입력 모듈과 UPC 모듈, 출력 모듈의 3부분으로 이루어지며, 편의상, UPC 모듈에서는 커넥션 테이블의 index를 VCI(Virtual channel Identifier)와 동일하게 할당하였다. 또한 UPC 모듈의VSA(Virtual Scheduling Algorithm)블럭에서 셀의 도착시간을 계수하는 카운터가 랩-어라운드(wrap-around)할 때 생기는 VSA의 오류를 보정하여 구현하였다.

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Dynamic Spacer UPC Algorithm Adopting Token Bucket for Traffic Control in ATM Network (토큰 버킷을 적용한 다이나믹 스페이서 UPC 알고리즘)

  • Park, Yong-Goun;Hahn, Hern-Soo
    • Proceedings of the Korean Society of Computer Information Conference
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    • pp.39-45
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    • 2008
  • ATM망에서 트래픽의 버스트니스를 완화하기 위한 UPC(Usage Parameter Control) 알고리즘을 제안한다. 기존의 다이나믹 스페이서는 그린 토큰이 축적되어 있을 경우 도착하는 셀을 스페이서와 상관없이 네트워크로 셀을 유입시키는 동적인 스페이서 기능을 수행함으로써 CDV(Cell Delay Variation)에 의한 셀을 위반셀로 구별하지 못하고 그대로 통과시키는 단점이 있다. 즉 스페이서 기능을 사용하지 않음으로써 버스트니스해 질 수 있다. 따라서 본 논문에서는 버스트니스를 완화하기 위한 토큰 버킷을 다이나믹 스페이서 이전에 사용함으로써 다이나믹 스페이서의 버스트니스를 완화시키는 토큰 버킷을 적용한 다이나믹 스페이서 UPC 알고리즘을 제안한다.

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Performance Analysis of the UPC/NPC Algorithm for Guaranteed QoS in ATM Networks

  • Kim, Yong-Jin;Kim, Jang-Kyung;Lee, Young-Hee;Park, Chee-Hang
    • ETRI Journal
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    • v.20 no.3
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    • pp.251-271
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    • 1998
  • It is well known that if usage parameter control/network parameter control (UPC/NPC) functions are used together with a cell loss priority control scheme in ATM networks, the measurement phasing problem can occur. This makes it difficult for a network provider to define and commit the cell loss ratio as a QoS parameter. To solve the problem, we propose a new UPC/NPC algorithm. By using the proposed UPC/NPC algorithm, we can define the cell loss ratios for CLP = 0 and CLP = 0+1 cell streams without the measurement phasing problem under any conditions. We analyzed the performance of the proposed UPC/NPC algorithm. Using a discrete time model for the UPC/NPC architecture with a discrete-time semi-Markov process (DSMP) input model, we obtained the cell discarding probabilities of CLP = 0 and CLP = 0+1 cells streams and showed that more CLP = 0 cells are accepted compared to what was proposed in ITU-T.

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Identification and Functional Characterization of a Cryptococcus neoformans UPC2 Homolog

  • Kim, Nam-Kyun;Han, Kyung-Hwan;Jung, Won-Hee
    • Mycobiology
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    • v.38 no.3
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    • pp.215-218
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    • 2010
  • Azoles are currently the most widely used class of antifungal drugs clinically, and are effective for treating fungal infections. Target site of azoles is ergosterol biosynthesis in fungal cell membrane, which is absent in the mammalian host. However, the development of resistance to azole treatments in the fungal pathogen has become a significant challenge. Here, we report the identification and functional characterization of a UPC2 homolog in the human pathogen Cryptococcus neoformans. UPC2 plays roles in ergosterol biosynthesis, which is also affected by the availability of iron in Saccharomyces cerevisiae and Candida albicans. C. neoformans mutants lacking UPC2 were constructed, and a number of phenotypic characteristics, including antifungal susceptibility and iron utilization, were analyzed. No differences were found between the mutant phenotypes and wild type, suggesting that the role of C. neoformans UPC2 homolog may be different from those in S. cerevisiae and C. albicans, and that the gene may have a yet unknown function.

Scalable Path Computation Flooding Approach for PCE-Based Multi-domain Networks

  • Perello, Jordi;Hernandez-Sola, Guillem;Agraz, Fernando;Spadaro, Salvatore;Comellas, Jaume
    • ETRI Journal
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    • v.32 no.4
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    • pp.622-625
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    • 2010
  • In this letter, we assess the scalability of a path computation flooding (PCF) approach to compute optimal end-to-end inter-domain paths in a path computation element-based multi-domain network. PCF yields a drastically reduced network blocking probability compared to a blind per-domain path computation but introduces significant network control overhead and path computation complexity. In view of this, we introduce and compare an alternative low overhead PCF (LoPCF) solution. From the obtained results, LoPCF leads to similar blocking probabilities to PCF while exhibiting around 50% path computation complexity and network control overhead reduction.