• Title, Summary, Keyword: 평균 반환 시간

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Analysis of Average Waiting Time and Average Turnaround Time in Web Environment (웹 환경에서의 평균 대기 시간 및 평균 반환 시간의 분석)

  • Lee, Yong-Jin
    • The KIPS Transactions:PartC
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    • v.9C no.6
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    • pp.865-874
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    • 2002
  • HTTP (HyperText Transfer Protocol) is a transfer protocol used by the World Wide Web distributed hypermedia system to retrieve the objects. Because HTTP is a connection oriented protocol, it uses TCP (Transmission control Protocol) as a transport layer. But it is known that HTTP interacts with TCP badly. it is discussed about factors affecting the performance or HTTP over TCP, the transaction time obtained by the per-transaction TCP connections for HTTP access and the TCP slow-start overheads, and the transaction time for T-TCP (Transaction TCP) which is one or methods improving the performance or HTTP over TCP. Average waiting time and average turnaround time are important parameters to satisfy QoS (Quality of Service) of end users. Formulas for calculating two parameters are derived. Such formulas can be used for the environment in which each TCP or T-TCP transaction time is same or different. Some experiments and computational experiences indicate that the proposed formulas are well acted, can be applied to the environment which the extension of bandwidth is necessary, and time characteristics of T-TCP are superior to that of TCP. Also, the load distribution method of web server based on the combination of bandwidths is discussed to reduce average waiting time and average turnaround time.

Design of an Efficient PC Cluster using a Very Large Idle PCs on Internet (인터넷상의 대규모 유휴 PC들을 사용한 효율적인 PC Cluster의 설계)

  • 김영균;최종욱;김용호;오길호
    • Proceedings of the Korean Information Science Society Conference
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    • pp.223-225
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    • 2002
  • 본 논문에서는 인터넷 상에서 대규모의 유휴 PC들을 연산에 활용하는 PC Cluster시스템에 대해 연구하였다. 인터넷상의 노드는 i)이질적이고, ii)각 노드의 신뢰성이 확보되지 않는 특징을 갖는다. 또한 각각의 노드는 iii)지역 작업을 가질 수 있다. 작업 할당시 연산에 참여하는 노드의 이력 정보와 유휴상태를 함께 고려하여 작업을 할당함으로서 i), ii)를 고려한 PC클러스터링 방법을 제안하였다. 작업 할당시 노드의 이전 작업들의 처리에 대한신뢰성과, 작업 반환 시간을 고려하여 작업을 노드에 할당함으로써 신뢰성이 떨어지는 노드와 평균 반환 시간이 상대적으로 다른 노드들에 비해 큰 노드에 대해서 작업 할당을 가능한 줄임으로써 전체 작업의 신뢰성을 높일 수 있고 평균 작업 반환 시간을 단축시킬 수 있다. 제안한 방법에서는 iii)의 지역 작업을 가질 수 있는 인터넷상의 서로 다른 성능의 이질적인PC로 Cluster를 구축할 경우 보다 적합한 Self-Scheduling을 사용함으로서 효율적으로 작업할당이 가능하도록 하였다. 제안한 방법은 지역 작업을 갖고 있는 인터넷상의 대규모 PC들로 구성된 신뢰성 있는 PC클러스터 구축을 가능하도록 한다.

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Autonomic Period Determination for Variable Rate Limiter of Virus Throttling (바이러스 감속기의 가변 비율 제한기를 위한 자율적 주기 결정)

  • Shim, Jae-Hong;Sohn, Jang-Wan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.1C
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    • pp.67-77
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    • 2007
  • Virus throttling technique, one of many early worm detection techniques, detects Internet worm propagation by limiting connect requests within a certain ratio. The typical virus throttling controls the period of rate limiter autonomically by utilizing weighted average delay queue length to reduce connection delay time without hanving a large effect on worm detection time. In the existing virus throttling research, a minimum period of variable rate limiter is fired and a turning point which is a point that the period of rate limiter has been being decreased and starts to be increased is also fixed. However, these two performance factors have different effects on worm detection time and connection delay. In this paper, we analyze the effect of minimum period and turning point of variable rate limiter, and then propose an algorithm which determines values of performance factors by referencing current traffic pattern. Through deep experiments, it is verified that the proposed technique is more efficient in respect of reducing worm detection time and connection delay than the existing virus throttling which fixed the performance factors.

Borrowing and Returning Mechanism for Fairness Control of DQOB-SR on Clinet-Server Environments. (클라이언트-서버 환경에서 슬롯 재사용 분산-큐 이중-버스의 공정성 제어를 위한 빌림과 반환 방식)

  • Kim, Jeong-Hong;Kwon, Oh-Seok
    • Journal of KIISE:Information Networking
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    • v.28 no.3
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    • pp.435-446
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    • 2001
  • In this paper, a new fairness control method is proposed to distribute DQDB-SR (Distributed-Queue Dual-Bus with Slot Reuse) network bandwidth fairly to all stations on client-server environments. By using an access limit that follows a characteristic of client-sever load patterns and a bandwidth borrowing and returning mechanism, the proposed mechanism imparts fairness bandwidth control capability to DQDB-SR. To implement the proposed mechanism, we find the optimal placement of erasure nodes that maximizes network capacity for DQDB-SR, and calculate the access limit. At overload conditions, simulation results show that the proposed mechanism does not deteriorate network throughput, and outperforms other fairness control mechanisms in a success rate and an average packet transfer delay.

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Analysis of Transient Characteristics of Load Sharing Algorithm (부하공유 알고리즘의 과도특성 해석)

  • 박세명
    • Proceedings of the Korea Society for Simulation Conference
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    • pp.15-15
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    • 1993
  • 기존의 부하공유에 대한 연구에서는 제안된 방법의 성능을 검증하기 위해서 각 처리기의 부하가 동일한 경우(homogeneous workload)와 각 처리기의 부하가 상이한 경우(heterogeneous workload)에 대해서 실험을 하고 있다. 처리기의 부하가 상이한 경우를 실험하기 위해서는 시스템내의 처리기중에서 부하를 발생시키는 처리기의 갯수, 처리기의 부하를 고부하, 저부하로 나뉘어질때 고부하 처리기의 비율, 그리고 각 처리기의 처리속도가 상이한 경우에 일정한 처리속도를 갖는 처리기의 비율의 변화에 따른 알고리즘의 성능을 평가하고 있다. 그러나 기존의 실험은 안정상태(steady state)의 경우에만 한정되어 있어 하루중 시간대에 따라서 처리기의 부하가 증감하는 현상을 보이는 실시스템의 환경을 정확히 반영하기는 어렵우므로 실험환경이 변화하는 시점, 즉 과도상태(transient state)에 대한 알고리즘의 분석이 필요하다. 본 연구에서는 각 처리기의 부하, 또는 시스템의 부하가 일시적으로 증가,또는 감소하는 과도상태하에서 기존의 부하공유 알고리즘의 동작 특성을 실험을 통해서 분석하였다. 이를 위해 기존의 부하공유 알고리즘중에서 송신자-시작, 수신자-시작, 그리고 송수신자-시작 알고리즘을 대상 알고리즘으로 선정하였으며, 성능평가를 위해서는 제출된 작업의 작업반환시간, 각 처리기에서 대기중인 작업의 평균 갯수와 표준편차를 이용하였다.

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A Light Weighted Robust Korean Morphological Analyzer for Korean-to-English Mobile Translator (한영 모바일 번역기를 위한 강건하고 경량화된 한국어 형태소 분석기)

  • Yuh, Sang-Hwa
    • Journal of the Korea Society of Computer and Information
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    • v.14 no.2
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    • pp.191-199
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    • 2009
  • In this paper we present a light weighted robust Korean morphological analyzer for mobile devices such as mobile phones, smart phones, and PDA phones. Such mobile devices are not suitable for natural language interfaces for their low CPU performance and memory restriction. In order to overcome the difficulties we propose 1) an online analysis by using Key Event Handler mechanism, 2) and a robust analysis of the Korean sentences with spacing errors without its correction pre-processing. We adapt the proposed Korean analyzer to a Korean-English mobile translator, which shows 5.8% memory usage reduction and 19.0% enhancement of average response time.

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A Name-based Service Discovering Mechanism for Efficient Service Delivery in IoT (IoT에서 효율적인 서비스 제공을 위한 이름 기반 서비스 탐색 메커니즘)

  • Cho, Kuk-Hyun;Kim, Jung-Jae;Ryu, Minwoo;Cha, Si-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.6
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    • pp.46-54
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    • 2018
  • The Internet of Things (IoT) is an environment in which various devices provide services to users through communications. Because of the nature of the IoT, data are stored and distributed in heterogeneous information systems. In this situation, IoT end applications should be able to access data without having information on where the data are or what the type of storage is. This mechanism is called Service Discovery (SD). However, some problems arise, since the current SD architectures search for data in physical devices. First, turnaround time increases from searching for services based on physical location. Second, there is a need for a data structure to manage devices and services separately. These increase the administrator's service configuration complexity. As a result, the device-oriented SD structure is not suitable to the IoT. Therefore, we propose an SD structure called Name-based Service-centric Service Discovery (NSSD). NSSD provides name-based centralized SD and uses the IoT edge gateway as a cache server to speed up service discovery. Simulation results show that NSSD provides about twice the improvement in average turnaround time, compared to existing domain name system and distributed hash table SD architectures.

Efficient Data Scheduling considering number of Spatial query of Client in Wireless Broadcast Environments (무선방송환경에서 클라이언트의 공간질의 수를 고려한 효율적인 데이터 스케줄링)

  • Song, Doohee;Park, Kwangjin
    • Journal of Internet Computing and Services
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    • v.15 no.2
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    • pp.33-39
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    • 2014
  • How to transfer spatial data from server to client in wireless broadcasting environment is shown as following: A server arranges data information that client wants and transfers data by one-dimensional array for broadcasting cycle. Client listens data transferred by the server and returns resulted value only to server. Recently number of users using location-based services is increasing alongside number of objects, and data volume is changing into large amount. Large volume of data in wireless broadcasting environment may increase query time of client. Therefore, we propose Client based Data Scheduling (CDS) for efficient data scheduling in wireless broadcasting environment. CDS divides map and then calculates total sum of objects for each grid by considering number of objects and data size within divided grids. It carries out data scheduling by applying hot-cold method considering total data size of objects for each grid and number of client. It's proved that CDS reduces average query processing time for client compared to existing method.

Processing of ρ-intersect Operation on RDF Data Using Suffix Array (RDF 데이터에서 접미사 배열을 이용한 ρ-intersect 연산의 처리)

  • Kim, Sung-Wan;Kim, Youn-Hee
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.7
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    • pp.95-103
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    • 2011
  • The actual utilization of Semantic Web technology which aims to provide more intelligent and automated service for information retrieval over the Web becomes gradually reality. RDF is widely used as the one of standard formats to present and manage the voluminous data on the Web. Efficient query processing on RDF data, therefore, is one of the ongoing research topics. Retrieving resources having a specific association from a given resource is the typical query processing type and several researches for this have done. However the most of previous researches have not fully considered discovering the complex relationship among resources such as returning the association between resources as the query processing result. This paper introduces the indexing and query processing for ${\rho}$-intersect operation which is one of the semantic association retrieval types. It includes an indexing scheme using suffix array and optimal processing approaches for handling ${\rho}$-intersect operation. The experimental evaluations shows that the average execution times for the proposed approach is 3~7 times faster than the previous approach.

A File System for User Special Functions using Speed-based Prefetch in Embedded Multimedia Systems (임베디드 멀티미디어 재생기에서 속도기반 미리읽기를 이용한 사용자기능 지원 파일시스템)

  • Choe, Tae-Young;Yoon, Hyeon-Ju
    • Journal of KIISE:Computing Practices and Letters
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    • v.14 no.7
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    • pp.625-635
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    • 2008
  • Portable multimedia players have some different properties compared to general multimedia file server. Some of those properties are single user ownership, relatively low hardware performance, I/O burst by user special functions, and short software development cycles. Though suitable for processing multiple user requests at a time, the general multimedia file systems are not efficient for special user functions such as fast forwards/backwards. Soml' methods has been proposed to improve the performance and functionality, which the application programs give prediction hints to the file system. Unfortunately, they require the modification of all applications and recompilation. In this paper, we present a file system that efficiently supports user special functions in embedded multimedia systems using file block allocation, buffer-cache, and prefetch. A prefetch algorithm, SPRA (SPeed-based PRefetch Algorithm) predicts the next block using I/O patterns instead of hints from applications and it is resident in the file system, so doesn't affect application development process. From the experimental file system implementation and comparison with Linux readahead-based algorithms, the proposed system shows $4.29%{\sim}52.63%$ turnaround time and 1.01 to 3,09 times throughput in average.