• Title/Summary/Keyword: 스케쥴러

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A Joint Power Allocation and Scheduling Algorithm for CDMA-based High-rate Packet Data Systems (CDMA기반 고속 패킷 데이터 전송 시스템을 위한 전력제어가 결합된 스케쥴링 알고리즘)

  • Koo In-Soo;Kim Ki-Seon
    • Journal of Internet Computing and Services
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    • v.7 no.3
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    • pp.41-51
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    • 2006
  • In the case of CDMA-based packet data systems such as 1xEV-DO which are designed to support high rate services, BSs transmit data packets with a maximum power based on time multiplexing mode such that only one user can be serviced at a time. In this paper, we propose a joint power allocation and scheduling algorithm for 1xEV-DO-like systems in which we adopt a code division multiplexing (CDM) transmission method in the downlink common channel in order to utilize channel orthogonality such that we can serve more than one user at a time slot especially when there exist remaining resources after serving the firstly selected user by the scheduler. Simulation results demonstrate that the proposed scheme can improve the performances of conventional schemes such as the maximum rate and the proportional fair algorithms.

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A Real-Time Performance Enhancement Scheme for Ethernet-based DAVIC Residential Network (이더네트 기반 DAVIC 주거망에서의 실시간 성능향상 기법)

  • Lee, Jung-Hoon;Kim, Sung-Baik;Kim, Tae-Woong
    • Journal of KIISE:Information Networking
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    • v.27 no.2
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    • pp.197-205
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    • 2000
  • This paper proposes and evaluates a scheme which enhances real-time performance on the Ethernet-based residential network where cable length is very short and most of traffic passes through a specific device. The scheme aims at enhancing deadline meet ratio of the real-time traffic, for example, video stream by means of applying the functionalities such as queue discrimination and early packet discard as well as maintaining network load properly. The design includes the description on hardware interfaces along with the software modules such as scheduler, device driver and connection manager. The simulation results via SMPL suggest that the proposed network can be used as a cost-effective residential network. We also measure the permissible bandwidth for non-real-time traffic without degrading the performance of real-time traffic.

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The Design of Process-Engine for Distributed Workflow Management System based on Web (웹기반 분산워크플로우 관리시스템의 프로세스 엔진 설계)

  • Lee, Heon;Park, Kyoo-Seok
    • Journal of Korea Multimedia Society
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    • v.4 no.5
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    • pp.377-389
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    • 2001
  • It has a tendency to build Workflow Systems based on the web with the spread of web environment. The important function in Workflow Systems are to automatize job flow according to the predefined regulations, procedures or conditions. Hence, there needs to consider excluding passive jobs, supporting GUI and a migratory information processing for information flow. Distributed Workflow System for workflow of a distributed service system should perform transfer control and Fault-Tolerance between tasks based on process logic, and real time processing. However, the existing mail systems being used are just for transmission and it doesn't fit to automatize job flow. To solve the matter, there needs a Distributed Workflow Engine to design workflow and automatize its control. In this paper, we design a web browser with graphic interface using web mail, a browser creating a script code for a procedural performance. Also, we design a Process-engine has a Preprocessor which tolerates process scheduler for task transaction or server node's faults on distributed environment. The proposed system enhances the reliability and usability of a system reduces the cost rather than a workflow system based on database, for they execute as proxy for a server's fault or suers' absence.

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The Development of Kernel-based Monitoring System for Grid Application (커널 기반 그리드 응용 모니터링 시스템의 개발)

  • Kim Tae-Kyung;Kim Dong-Su;Byeon Ok-Hwan;Chung Tai M.
    • The KIPS Transactions:PartC
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    • v.11C no.6 s.95
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    • pp.821-828
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    • 2004
  • To analyze the usage information of system and network resources to the each grid application by measuring the real time traffic and calculating the statistic information, we suggested the kernel-based monitoring methods by researching the efficient monitoring method. This method use small system resourcesand measure the monitoring information accurately with less delay than the usual packet capture methods such as tcpdump. Also we implemented the monitoring systems which can monitor the used resources of system and network for grid application using the suggested kernel-based monitoring method. This research can give the useful information to the development of grid application and to grid network scheduler which can assign the proper resources to the grid application to perform efficiently. Network administrator can decide whether the expansion of network is required or not using the monitoring information.

The Customer Premise Platform for Processing Multimedia Data on the ATM network (ATM망의 멀티미디어 데이터 처리를 위한 가입자단 플랫폼)

  • Kim Yunhong;Son Yoonsik
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.2 s.332
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    • pp.89-96
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    • 2005
  • In this paper, we propose a customer premise platform for processing multimedia data service on the ATM network. The proposed platform has a specific AAL2 processor that includes AAL2 protocol and scheduler algorithm so as to off-load large potion of burden from host processor and make it easy to process multimedia data from the ATM network in real time compared with conventional platform in which AAL/ATM tasks are processed by software. The ATS scheduler that is implemented based on 2-level time slot ring provides a simple and efficient method for scheduling data of VBR-rt, UBR and CBR traffics. TMS320C5402 DSP is used to process voice-related tasks such as voice compression and voice packet manupulation and AAL2 processor is implemented on $0.35\;{\mu}m$ process line. We implemented the customer premise equipment for VoDSL service and tested the proposed platform on a test bed network. The experimental results show that the proposed equipment has the call success rate of $97\%$ at least and provides voice service of toll-qualify.

Implementation and TCP Performance Measurement of RED scheduler using NetFPGA platform (NetFPGA 플랫폼 기반 RED스케줄러 구현 및 TCP 성능평가)

  • Oh, Min-Kyung;Min, Seok-Hong;Kim, Byung-Chul;Lee, Jae-Yong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.3
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    • pp.27-36
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    • 2012
  • With the increase of various user's requirements, lots of interesting applications on the Internet have been emerging recently. However, Internet has many limitations for providing upcoming new services because it was only designed to provide basic connectivity between research networks and simplified forwarding functions at the first time. Internet has many problems in the aspects of routing scalability, mobility, security and QoS, so lots of researches are being actively performed in many countries to solve these problems. In this paper, we implement RED(Random Early Detection) scheduler using NetFPGA platform and local testbed to provide active queue management. Using the implemented RED scheduler, packets are dropped according to the specified drop probability, so Global Synchronization coming from simultaneous TCP segment losses in a congestion condition can be prevented. With the comparison to the Drop-Tail scheme in the basic router, we show TCP performance can be enhanced in the congestion situation using the NetFPGA-based RED scheduler.

Design and Implementation of National Supercomputing Service Framework (국가 슈퍼컴퓨팅 서비스 프레임워크의 설계 및 구현)

  • Yu, Jung-Lok;Byun, Hee-Jung;Kim, Han-Gi
    • KIISE Transactions on Computing Practices
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    • v.22 no.12
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    • pp.663-674
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    • 2016
  • Traditional supercomputing services suffer from limited accessibility and low utilization in that users(researchers) may perform computational executions only using terminal-based command line interfaces. To address this problem, in this paper, we provide the design and implementation details of National supercomputing service framework. The proposed framework supports all the fundamental primitive functions such as user management/authentication, heterogeneous computing resource management, HPC (High Performance Computing) job management, etc. so that it enables various 3rd-party applications to be newly built on top of the proposed framework. Our framework also provides Web-based RESTful OpenAPIs and the abstraction interfaces of job schedulers (as well as bundle scheduler plug-ins, for example, LoadLeveler, Open Grid Scheduler, TORQUE) in order to easily integrate the broad spectrum of heterogeneous computing clusters. To show and validate the effectiveness of the proposed framework, we describe the best practice scenario of high energy physics Lattice-QCD as an example application.

A Modified Proportional Scheduler and Evaluation Method (수정 비례 지분 스케쥴러 및 평가법 설계)

  • 김현철;박정석
    • Journal of Internet Computing and Services
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    • v.3 no.2
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    • pp.15-26
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    • 2002
  • Since multimedia data such as video and audio data are displayed within a certain time constraint, their computation and manipulation should be handled under limited condition. Traditional real-time scheduling algorithms could net be directly applicable, because they are not suitable for multimedia scheduling applications which support many clients at the same time. Rate Regulating Proportional Share Scheduling Algorithm is a scheduling algorithm considered the time constraint of the multimedia data. This scheduling algorithm uses a rate regulator which prevents tasks from receiving more resource than its share in a given period. But this algorithm loses fairness, and does not show graceful degradation of performance under overloaded situation, This paper proposes a new modified algorithm. namely Modified Proportional Share Scheduling Algorithm considering the characteristics of multimedia data such as its continuity and time dependency, Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and the reduction in the number of context switching, Furthermore, a new evaluation method is proposed which can evaluate the flexibility of scheduling algorithm.

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A Scheduler for Multimedia Data and Evaluation Method (멀티미디어 데이터를 위한 스케쥴러 및 평가법 설계)

  • 유명련;김현철
    • Journal of the Institute of Convergence Signal Processing
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    • v.3 no.2
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    • pp.1-7
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    • 2002
  • Since multimedia data such as video and audio data are displayed within a certain time constraint, their computation and manipulation should be handled under limited condition. Traditional real-time scheduling algorithms could not be directly applicable, because they are not suitable for multimedia scheduling applications which support many clients at the same time. Rate Regulating Proportional Share Scheduling Algorithm is a scheduling algorithm considered the time constraint of the multimedia data. This scheduling algorithm uses a rate regulator which prevents tasks from receiving more resource than its share in a given period. But this algorithm loses fairness, and does not show graceful degradation of performance under overloaded situation. This paper proposes a new modified algorithm, namely Modified Proportional Share Scheduling Algorithm considering the characteristics of multimedia data such as its continuity and time dependency. Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and the reduction in the number of context switching. Furthermore, a new evaluation method is proposed which can evaluate the flexibility of scheduling algorithm.

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Rate-Monotonic Scheduler with Extended Schedulability Inspection for Hard Real-Time Tesk (경성 실시간 태스크를 위한 확장된 스케줄 가능성 검사를 갖는 비율단조 스케줄러)

  • 신동헌;조수현;김영학;김태형
    • The Journal of the Korea Contents Association
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    • v.4 no.2
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    • pp.50-60
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    • 2004
  • Recently, most of the embedded system is required not only many functions but also real-time characteristics in purpose. In the hard real-time system, especially, strict deadline of periodic task can affect the performance of the system. In this paper, we design and implement the scheduler based on RM(Rate-Monotonic) rule. This scheduler makes feasible patterns based on EDF(Earliest deadline first) rule with extended schedulability inspection before execution, for periodic task-set that has high CPU utilization and then, execute periodic task-set depended on feasible patterns. The feasible pattern formed into EDF rule is capable of the efficiency of CPU up to 100 percentage and by the referenced execution of the feasible pattern is possible of removing the red-time scheduling overhead that is the defect of the order of dynamic assignment rule.

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