• Title/Summary/Keyword: Priority-based control

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Design and Analsis of a high speed switching system with two priority (두개의 우선 순위를 가지는 고속 스윗칭 시스템의 설계 및 성능 분석)

  • Hong, Yo-Hun;Choe, Jin-Sik;Jeon, Mun-Seok
    • The KIPS Transactions:PartC
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    • v.8C no.6
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    • pp.793-805
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    • 2001
  • In the recent priority system, high-priority packet will be served first and low-priority packet will be served when there isn\`t any high-priority packet in the system. By the way, even high-priority packet can be blocked by HOL (Head of Line) contention in the input queueing System. Therefore, the whole switching performance can be improved by serving low-priority packet even though high-priority packet is blocked. In this paper, we study the performance of preemptive priority in an input queueing switch for high speed switch system. The analysis of this switching system is taken into account of the influence of priority scheduling and the window scheme for head-of-line contention. We derive queue length distribution, delay and maximum throughput for the switching system based on these control schemes. Because of the service dependencies between inputs, an exact analysis of this switching system is intractable. Consequently, we provide an approximate analysis based on some independence assumption and the flow conservation rule. We use an equivalent queueing system to estimate the service capability seen by each input. In case of the preemptive priority policy without considering a window scheme, we extend the approximation technique used by Chen and Guerin [1] to obtain more accurate results. Moreover, we also propose newly a window scheme that is appropriate for the preemptive priority switching system in view of implementation and operation. It can improve the total system throughput and delay performance of low priority packets. We also analyze this window scheme using an equivalent queueing system and compare the performance results with that without the window scheme. Numerical results are compared with simulations.

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A Packet Loss Control Scheme based on Network Conditions and Data Priority (네트워크 상태와 데이타 중요도에 기반한 패킷 손실 제어 기법)

  • Park, Tae-Uk;Chung, Ki-Dong
    • Journal of KIISE:Information Networking
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    • v.31 no.1
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    • pp.1-10
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    • 2004
  • This study discusses Application-layer FEC using erasure codes. Because of the simple decoding process, erasure codes are used effectively in Application-layer FEC to deal with Packet-level errors. The large number of parity packets makes the loss rate to be small, but causes the network congestion to be worse. Thus, a redundancy control algorithm that can adjust the number of parity packets depending on network conditions is necessary. In addition, it is natural that high-priority frames such as I frames should produce more parity packets than low-priority frames such as P and B frames. In this paper, we propose a redundancy control algorithm that can adjust the amount of redundancy depending on the network conditions and depending on data priority, and test the performance in simple links and congestion links.

Prioritized Packet Reservation CDMA Protocolfor Integrated Voice and Data Services (CDMA 망에서의 음성 및 데이터 통합 서비스를 위한 우선권 기반의 패킷 예약 접속 프로토콜)

  • Kim, Yong-Jin;Kang, Chung-Gu
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.1
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    • pp.32-43
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    • 2000
  • In this paper, we investigate the existing medium access control (MAC) protocols to integrate the voice and data services in packet-based CDMA networks and furthermore, propose a new approach to circumvent the operational limits inherent in them. We propose the $P^2R$-CDMA (Prioritized Packet Reservation Code Division Multiple Access) protocol for the uplink in the synchronous multi-code CDMA system, which employs the centralized frame-based slot reservation along with the dynamic slot assignment in the base station using the QoS-oriented dynamic priority of individual terminal. The simulation results show that, as compared with the existing scheme based on the adaptive permission probability control (APC), the proposed approach can significantly improve the system capacity while guaranteeing the real-time requirement of voice service.

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Traffic control issues for ATM networks (ATM 망에 대한 트래픽 제어의 문제점 분석)

  • 최영철;조유제;최문기
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1991.10a
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    • pp.179-182
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    • 1991
  • In this paper, we survey traffic control issues for the B-ISDN based on the ATM. We first investigate traffic descriptors to represent the characteristics of various ATM traffics in a standardized form. Also, we examine key issues related to the connection admission control, usage parameter control, network parameter control, priority control, and congestion control.

An Efficient Rate Control Protocol for Wireless Sensor Network Handling Diverse Traffic

  • Monowar, Muhammad Mostafa;Rahman, Md. Obaidur;Hong, Choong-Seon
    • Proceedings of the Korean Information Science Society Conference
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    • 2007.10a
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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.

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Analysis of traffic control policies in the voice-date integrated cellular CDMA mobile network (음성 및 데이터가 혼합된 CDMA 셀룰러 망에서의 트래픽 제어 분석 방법)

  • Yoon, Bok-Sik;Lee, Nam-Jun;Lee, Dong-Kie;Lie, Chang-Hoon
    • Journal of Korean Institute of Industrial Engineers
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    • v.22 no.4
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    • pp.771-788
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    • 1996
  • A CDMA-based cellular mobile telecommunication system has already been developed and is expected to provide more stable mobile communication services for much more users than traditional analog mobile systems. As a natural course of development, the CDMA mobile system is expected to provide ISDN services in the near future. In this paper, we analyze several traffic control policies for the voice-data integrated traffic in the cellular CDMA system. We first select four admission control policies which take differences in traffic and QOS characteristics between voice and data into account, and then develop modelling and analysis techniques, which can be used directly to analyze the chosen control policies. Our approach is based on so-called threshold model. Numerical computation results obtained under the typical traffic situation are also given. Through these computation results we could tentatively conclude that the cutoff priority policy, which can provide the priority for handoff voice cells while effectively utilizing unused channels, seems to be most effective among the four policies.

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Evaluating genetic diversity and identifying priority conservation for seven Tibetan pig populations in China based on the mtDNA D-loop

  • Ge, Qianyun;Gao, Caixia;Cai, Yuan;Jiao, Ting;Quan, Jinqiang;Guo, Yongbo;Zheng, Wangshan;Zhao, Shengguo
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.12
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    • pp.1905-1911
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    • 2020
  • Objective: Tibetan pigs, an excellent species unique to China, face serious threats, which in turn affects the development and utilization of the outstanding advantages of plateau hypoxia adaptability and reduces their genetic diversity. Therefore, a discussion of measures to conserve this genetic resource is necessary. The method, based on genetic diversity, genetic divergence and total genetic contribution rate of population, reflects the priority conservation order and varies depending on the three different purposes of conservation. Methods: We analyzed mitochondrial DNA control region (D-loop) variation in 1,201 individuals from nine Tibetan pig populations across five provinces and downloaded 564 mtDNA D-loop sequences from three indigenous pig breeds in Qinghai, Sichuan, and Yunnan Provinces distributed near the Tibetan pigs. Results: We analyzed three different aspects: Changdu Tibetan pigs have the highest genetic diversity, and from the perspective of genetic diversity, the priority conservation is Changdu Tibetan pigs. Hezuo Tibetan pigs have the highest genetic contribution, so the priority conservation is Hezuo Tibetan pigs in the genetic contribution aspect. Rkaze Tibetan pigs were severely affected by indigenous pig breeds, so if considering from the perspective of introgression, the priority conservation is Rkaze Tibetan pigs. Conclusion: This study evaluated genetic diversity and comprehensively assessed conservation priority from three different aspects in nine Tibetan pig populations.

Task Reconstruction Method for Real-Time Singularity Avoidance for Robotic Manipulators : Dynamic Task Priority Based Analysis (로봇 매니플레이터의 실시간 특이점 회피를 위한 작업 재구성법: 동적 작업 우선도에 기초한 해석)

  • 김진현;최영진
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.10
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    • pp.855-868
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    • 2004
  • There are several types of singularities in controlling robotic manipulators: kinematic singularity, algorithmic singularity, semi-kinematic singularity, semi-algorithmic singularity, and representation singularity. The kinematic and algorithmic singularities have been investigated intensively because they are not predictable or difficult to avoid. The problem with these singularities is an unnecessary performance reduction in non-singular region and the difficulty in performance tuning. Tn this paper, we propose a method of avoiding kinematic and algorithmic singularities by applying a task reconstruction approach while maximizing the task performance by calculating singularity measures. The proposed method is implemented by removing the component approaching the singularity calculated by using singularity measure in real time. The outstanding feature of the proposed task reconstruction method (TR-method) is that it is based on a local task reconstruction as opposed to the local joint reconstruction of many other approaches. And, this method has dynamic task priority assignment feature which ensures the system stability under singular regions owing to the change of task priority. The TR-method enables us to increase the task controller gain to improve the task performance whereas this increase can destabilize the system for the conventional algorithms in real experiments. In addition, the physical meaning of tuning parameters is very straightforward. Hence, we can maximize task performance even near the singular region while simultaneously obtaining the singularity-free motion. The advantage of the proposed method is experimentally tested by using the 7-dof spatial manipulator, and the result shows that the new method improves the performance several times over the existing algorithms.

Performance Analysis of a Congestion cControl Mechanism Based on Active-WRED Under Multi-classes Traffic (멀티클래스 서비스 환경에서 Active-WRED 기반의 혼잡 제어 메커니즘 및 성능 분석)

  • Kim, Hyun-Jong;Kim, Jong-Chan;Choi, Seong-Gon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.45 no.5
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    • pp.125-133
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    • 2008
  • In this paper, we propose active queue management mechanism (Active-WRED) to guarantee quality of the high priority service class in multi-class traffic service environment. In congestion situation, this mechanism increases drop probability of low priority traffic and reduces the drop probability of the high priority traffic, therefore it can improve the quality of the high priority service. In order to analyze the performance of our mechanism we introduce the stochastic analysis of a discrete-time queueing systems for the performance evaluation of the Active Queue Management (AQM) based congestion control mechanism called Weighted Random Early Detection (WRED) using a two-state Markov-Modulated Bernoulli arrival process (MMBP-2) as the traffic source. A two-dimensional discrete-time Harkov chain is introduced to model the Active-WRED mechanism for two traffic classes (Guaranteed Service and Best Effort Service) where each dimension corresponds to a traffic class with its own parameters.