• Title/Summary/Keyword: queueing analysis

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Empirical Evaluation of BIM Coordinator Performance using Queuing Model in Construction Phase (대기행렬 모형을 활용한 시공단계 BIM 코디네이터 업무 성과 분석)

  • Ham, Nam-Hyuk;Yuh, Ok-Kyung;Ji, Kyu-Hyun
    • Journal of KIBIM
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    • v.8 no.3
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    • pp.31-42
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    • 2018
  • This study focuses on the BIM request for information(RFI) processing performance and quantitatively analyzes the performance of the BIM coordinator and the loss due to the waiting of the project participants. For these purposes, a method to quantitatively evaluate the performance of the BIM coordinator was proposed using a queueing model. For the verification, two projects in which BIM was applied in the construction phase were selected, and the BIM RFI data were collected through the analysis of the BIM monthly report and BIM coordinator work log of each project. In addition, the BIM input personnel, labor cost, and productivity data were collected through interviews with the experts of the case projects. The analysis of the BIM RFI processing performance of the BIM coordinator using the queueing model exhibited on a probabilistic basis that the waiting status of the project participants could vary depending on the preliminary BIM application to the design verification as well as the input number and level of the BIM coordinator personnel. In addition, the loss cost due to the waiting of the project participants was analyzed using the number of BIM RFIs waiting to be processed in the queueing system. Finally, the economic feasibility analysis for the optimal BIM coordinator input was performed considering the loss cost. The results of this study can be used to make decisions about the optimal BIM coordinator input and can provide grounds for the BIM return on investment (ROI) analysis considering the waiting cost of the project participants.

An Analysis of the Port Transportation System (항만운송시스템의 분석에 관한 연구)

  • 이철영;문성혁
    • Journal of the Korean Institute of Navigation
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    • v.7 no.1
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    • pp.1-32
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    • 1983
  • The delay due to congestion has recently attracted widespread attention with the analysis of over-all operation at the port. But, the complexity of the situation is evident in view of the large number of factors which impinge on the considerable end. Queueing theory is applicable to a large scale transportation system which is associated with arrivals of vessels in a large port. The attempt of this paper is to make an extensive analysis of the port transport system and its economic implications from the viewpoint that port is one of the physical distribution facilities and a kind of queueing system which includes ships and cargoes as port customer. By analyzing the real data on the Port of Pusan, it is known that this port can be represented as a set of multi-channel with identical setof Poisson arrival and Erlang service time, and also it is confirmed that the following formula is suitable to calculate the mean delay in this port, namely, $W_4={\frac{\rho}{\lambda(1-\rho)} {\frac{e_N(\rho{\cdot}N)}{D_{N-1}(\rho{\cdot}N)}$ where, ${\lambda}$: mean arrival rate $\mu$: mean servicing rate; N: number of servicing channel; ${\rho}$: utillization rate (${\lambda}/N{\mu}$) $e_N$: the Poisson function Coming to grips with the essentials of the cost of delay due to congestion, a simple ship journey cost model is adopted and the operating profit sensitivity to variation in port time is examined, and for purpose of a future development for port princing service the marginal cost is approximately calculated on the basis of queueing theory.

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Performance Analysis of a WCSFQ (Weighted Core-Stateless Fair Queueing)-like Space Priority Policy for ATM nodes (ATM 노드를 위한 WCSFQ-유사 공간 우선순위 정책의 성능분석)

  • Kang, Koo-Hong
    • The KIPS Transactions:PartC
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    • v.12C no.5 s.101
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    • pp.687-694
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    • 2005
  • In ATM and W networks, high Priority Packets should be selectively favored over low Priority Packets in case of congestion. For this purpose, we introduce a space priority policy for ATM nodes in this paper which is very similar to the weighted core-stateless fair queueing(WCSFQ) in IP nodes. We also analyze the loss probabilities for different classes of cells for MMPP/D/1/K with a threshold level, and discuss the numerical results. The numerical results illustrate that the WCSFQ scheme can be used to support the differentiated services in ATM or IP nodes.

Excess Bandwidth Hierarchical Fair Queueing Using Excess Bandwidth Consumer Queue (잉여 대역폭 소비 큐를 이용한 계층적 잉여 대역폭 페어 큐잉)

  • 김영한;추호철
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.12
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    • pp.1-8
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    • 2003
  • Scheduling technology is one of the most important elements required to support the Quality of service (QoS) in the Internet and a lot of scheduling algorithms have been developed. However, most of these algorithms ire not flexible to distribute the excess bandwidth. In order to provide flexibility for distributing the excess bandwidth, we proposed excess bandwidth fair queueing (EBFQ) algorithm with relatively low complexity. In this paper, we propose the new extension to this EBFQ algorithm for the hierarchical fair queueing system. This extension can be naturally applied to the existing hierarchical algorithm and simultaneously provide the same level of fairness. Through the simulation and analysis, we verify it.

A System Analysis of a Controllable Queueing Model Operating under the {T:Min(T,N)} Policy (조정가능한 대기모형에 {T:Min(T,N)} 운용방침이 적용되었을 때의 시스템분석)

  • Rhee, Hahn-Kyou
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.1
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    • pp.21-29
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    • 2015
  • A steady-state controllable M/G/1 queueing model operating under the {T:Min(T,N)} policy is considered where the {T:Min(T,N)} policy is defined as the next busy period will be initiated either after T time units elapsed from the end of the previous busy period if at least one customer arrives at the system during that time period, or after T time units elapsed without a customer' arrival, the time instant when Nth customer arrives at the system or T time units elapsed with at least one customer arrives at the system whichever comes first. After deriving the necessary system characteristics including the expected number of customers in the system, the expected length of busy period and so on, the total expected cost function per unit time for the system operation is constructed to determine the optimal operating policy. To do so, the cost elements associated with such system characteristics including the customers' waiting cost in the system and the server's removal and activating cost are defined. Then, procedures to determine the optimal values of the decision variables included in the operating policy are provided based on minimizing the total expected cost function per unit time to operate the queueing system under considerations.

Performance Relation Analysis of CLR, Buffer Capacity and Delay Time in the ATM Access Node (ATM 접속노드에서 셀 손실율과 버퍼용량 및 지연시간의 상관관계 분석)

  • 이하철;이병섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.10C
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    • pp.945-950
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    • 2002
  • In this paper the performance evaluations on Asynchronous Transfer Mode(ATM) access node are performed in the ATM access network which consists of access node and channel. The performance factors of access node are Cell Loss Ratio(CLR), buffer capacity and delay time. Both the ATM cell-scale queueing model and burst-scale queueing model are considered as the traffic model of access node for various traffic types such as Constant Bit Rate(CBR), Variable Bit Rate(VBR) and random traffic in the ATM access networks. Based on these situations, the relation of CLR, buffer capacity and delay time is analyzed in the ATM access node.

Efficient Packet Scheduling Algorithm using Virtual Start Time for High-Speed Packet Networks (고속 패킷망에서 효율적인 가상 시작 시간 기반 패킷 스케줄링 알고리즘)

  • Ko, Nam-Seok;Gwak, Dong-Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.3B
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    • pp.171-182
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    • 2003
  • In this paper, we propose an efficient and simple fair queueing algorithm, called Minimum Possible Virtual Start Time Fair Queueing (MPSFQ), which has O(1) complexity for the virtual time computation while it has good delay and fairness properties. The key idea of MPSFQ is that it has an easy system virtual time recalibration method while it follows a rate-proportional property. MPSFQ algorithm recalibrates system virtual time to the minimum possible virtual start time of all backlogged sessions. We will show our algorithm has good delay and fairness properties by analysis.

Analysis of a Wireless Transmitter Model Considering Retransmission for Real Time Traffic (재전송을 고려한 무선 전송 단에서 실시간 데이터 전송 모델의 분석)

  • Kim, Tae-Yong;Kim, Young-Yong
    • Proceedings of the KIEE Conference
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    • 2005.05a
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    • pp.215-217
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    • 2005
  • There are two types of packet loss probabilities used in both the network layer and the physical layer within the wireless transmitter such as a queueing discard probability and transmission loss probability. We analyze these loss performances in order to guarantee Quality of Service (QoS) which is the basic of the future network. The queuing loss probability is caused by a maximum allowable delay time and the transmission loss probability is caused by a wireless channel error. These two types of packet loss probabilities are not easily analyzed due to recursive feedback which, originates as a result at a queueing delay and a number of retransmission attempts. We consider a wireless transmitter to a M/D/1 queueing model. We configurate the model to have a finite-size FIFO buffer in order to analyze the real-time traffic streams. Then we present the approaches used for evaluating the loss probabilities of this M/D/1/K queueing model. To analyze the two types of probabilities which have mutual feedbacks with each other, we drive the solutions recursively. The validity and accuracy of the analysis are confirmed by the computer simulation. From the following solutions, we suggest a minimum of 'a Maximum Allowable Delay Time' for real-time traffic in order to initially guarantee the QoS. Finally, we analyze the required service rate for each type utilizing real-time traffic and we apply our valuable analysis to a N-user's wireless network in order to get the fundamental information (types of supportable real-type traffics, types of supportable QoS, supportable maximum number of users) for network design.

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A Workflow Time Analysis Applying the Queueing Model (대기행렬모형에 의한 워크플로우 시간분석)

  • Park, Jinsoo
    • Journal of the Korea Society for Simulation
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    • v.23 no.3
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    • pp.1-9
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    • 2014
  • Traditional workflow time analyses have been performed treating an activity as an independent M/M/1queueing system. Using the general forms of performance measures in the M/M/1 system, various aspects of analyses can be performed. Especially, on the time analysis of an AND structure in a workflow system, the mean system sojourn time can be formalized by applying the performance measures of M/M/1 system. In the real workflow system, the AND structure cannot be described correctly under the assumption of independent M/M/1 systems. To overcome this limitation, this research makes the assumption that the all activities for a task starts simultaneously. In this situation, the theoretical solution can be derived using the performance measures of the M/G/1 system. In addition, the simulation modeling method will be proposed to analyze the AND structure of a real workflow system. Finally, some numerical results from the theoretical solutions and simulation models will be provided for verification. The main performance measures used in this research are mean queueing time and mean sojourn time.

QUEUEING ANALYSIS OF GATED-EXHAUSTIVE VACATION SYSTEM FOR DBA SCHEME IN AN EPON

  • HAN DONG HWAN;PARK CHUL GEUN
    • Journal of applied mathematics & informatics
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    • v.17 no.1_2_3
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    • pp.547-557
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    • 2005
  • In this paper, we investigate the packet delay distribution of a dynamic bandwidth allocation(DBA) scheme in an Ethernet passive optical network(EPON). We focus on the gated-exhaustive vacation system. We assume that input packets arrive at an optical network unit(ONU) according to general interarrival distribution. We use a discrete time queueing model in order to find the packet delay distribution of the gated-exhaustive system with the primary transmission queue and the secondary input queue. We give some numerical examples to investigate the mean packet delays of the proposed queueing model to analyze the DBA scheme in an EPON.