• Title/Summary/Keyword: Uniform traffic

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A Fuzzy Traffic Controller Considering the spillback on the Multiple Crossroads

  • Kim, Young-Sik
    • Journal of the Korean Institute of Intelligent Systems
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    • v.13 no.6
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    • pp.722-728
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    • 2003
  • In this paper, we propose a fuzzy traffic controller of Sugeno`s fuzzy model so as to model the nonlinear characteristics of controlling the traffic light. It use a degree of the traffic congestion of the preceding roads as an input so that it can cope with traffic congestion appropriately, which causes the loss of fuel and our discomfort. First, in order to construct fuzzy traffic controller of Sugeno`s fuzzy model, we model the control process of the traffic light by using Mamdani`s fuzzy model, which has the uniform membership functions of the same size and shape. Second, we make Mamdani`s fuzzy model with the non-uniform membership functions so that it can exactly reflect the knowledge of experts and operators. Last, we construct the fuzzy traffic controller of Sugeno`s fuzzy model by learning from the input/output data, which is retrieved from Mamdani`s fuzzy model with the non-uniform membership functions. We compared and analyzed the fixed traffic light controller, the fuzzy traffic controller of Mamdani`s fuzzy model and the fuzzy traffic controller of Sugeno`s fuzzy model by using the delay time and the proportion of the entered vehicles to the occurred vehicles. As a result of comparison, the fuzzy traffic controller of Sugeno`s fuzzy model showed the best performance.

Fuzzy Traffic Controller of Sugeno′s Model

  • Kim, Young-Sik;Lee, Jae-Hoon;Park, Wan-Kyoo;Lee, Sung-Joo
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.664-667
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    • 2003
  • We propose a frizzy traffic controller of Sugeno's fuzzy model so as to model the nonlinear characteristics of controlling the traffic light. It uses a degree of the traffic congestion of the preceding roads as an input so that it can cope with traffic congestion appropriately, which causes the loss of fuel and our discomfort. In order to construct fuzzy traffic controller of Sugeno's fuzzy model we first model the control process of the traffic light by using Mamdani's fuzzy model, which has the uniform membership functions of the same size and shape. Next we make Mamdani's fuzzy model with the non-uniform membership functions so that it can exactly reflect the knowledge of experts and operators. Lastly, we construct the fuzzy traffic controller of Sugeno's fuzzy model by learning from the input/output data, which is retrieved from Mamdani's fuzzy model with the non-uniform membership functions. We compared and analyzed the service level of the traffic light controllers by using the delay time. As a result of comparison, the fuzzy traffic controller of Sugeno's fuzzy model shows the best service level of them.

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Effects of Non-Uniform Traffic Distribution on the Capacity of Reverse Link CDMA System

  • Cho, Choon-Geun;Ann, Jong-Hoon;Tchah, Kyun-Hyon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.12A
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    • pp.1828-1835
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    • 2000
  • In this paper, we analyzed the other-cell interference characteristics for various non-uniform traffic distributions and their effects on the capacity of multi-cell CDMA system. We consider three different traffic distributions, i.e., linear, exponential and Gaussian traffic distribution with distribution parameters. Changing the distribution parameter, we can obtain the center-focused distributions or uniform distributions for each model. From the results of other-cell interference calculation we can see that the other-cell interference decreases, as the user concentrates on the base station. Also using frequency reuse efficiency indicating the capacity reduction of a multi-cell system when compared to a single cell system, we evaluate the effect of traffic distribution on the reverse link CDMA capacity. For linear case, the capacity of multi-cell system is reduced to 0.637∼0.867 times that of single cell system. On the other hand, for both exponential and Gaussian cases, the capacity under a multi-cell environment is equal to 70∼100% of that under a single cell. Therefore, we conclude that the average capacity of multi-cell CDMA system are increased when users are likely to be at near the cell base station due to reduced total other-cell interference and decreased when users exist at near the cell edge regardless of traffic distribution models.

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Approximate Analysis of MAC Protocol with Multiple Self-tokens in a Slotted Ring

  • Sakuta, Makoto;Sasase, Iwao
    • Journal of Communications and Networks
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    • v.5 no.3
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    • pp.249-257
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    • 2003
  • Ring networks are very commonly exploited among local area and metropolitan area networks (LAN/MAN), whereas cells or small fixed-size packets are widely used in synchronized ring networks. In this paper, we present an analytical method for evaluating the delay-throughput performance of a MAC protocol with multiple self-tokens in a slotted ring network under uniform traffic. In our analysis, we introduce the stationary probability, which indicates the number of packets in a node. Also, it is assumed that each node has a sufficiently large amount of self-tokens, and a slotted ring has the symmetry. The analytical results with respect to delay-throughput performance have similar values to computer simulated ones. Furthermore, in order to achieve fair access under non-uniform traffic, we propose an adaptive MAC protocol, where the number of self-tokens in a node dynamically varies, based on the number of packets transmitted within a specified period. In the proposed protocol, when the number of packets transmitted by a node within a specified period is larger than a specified threshold, the node decreases the number of self-tokens in a per-node distributed method. That results in creating free slots in the ring, thus all nodes can obtain an equal opportunity to transmit into the ring. Performance results obtained by computer simulation show that our proposed protocol can maintain throughput fairness under non-uniform traffic.

Calculation of Reasonable Equivalent Uniform Pressure Height and Lateral Earth Pressure Characteristics of Retaining Structures (옹벽에 작용하는 수평토압 특성 분석 및 합리적인 등가상재하중 높이 산정)

  • Lee, Kicheol;Chung, Moon-Kyung;Seo, Seunghwan;Kim, Dongwook
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.4
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    • pp.139-149
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    • 2019
  • For retaining wall designs, horizontal earth pressure induced by traffic loads over the walls is calculated based on equivalent uniform pressure height. The AASHTO LRFD design standards propose equivalent uniform pressure height of traffic loads; however, the equivalent uniform pressure height is calibrated using the US standard trucks. As the domestic standard trucks are different from the US standard trucks, in this study, new domestic equivalent uniform pressure height is proposed using the Boussinesq theory varying vehicle directions, Poisson's ratios of pavement layers, and retaining wall height. The proposed equivalent uniform pressure heights are generally higher than those proposed by the AASHTO design standards because the axle loads and their densities of two domestic standard trucks are higher than those of the US standard trucks. The most highest equivalent uniform pressure height was found for traffic direction perpendicular to longitudinal direction of retaining wall.

A New Traffic Load Shedding Scheme in Microcellular CDMA with Uniform and Non-uniform Traffic Load

  • Park, Woo-Goo;Rhee, Ja-Gan;Lee, Hu;Lee, Sang-Ho
    • Journal of Electrical Engineering and information Science
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    • v.2 no.5
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    • pp.33-39
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    • 1997
  • In this paper we proposed a new traffic load shedding scheme which maximizes the throughput of traffic control by decreasing the load of the hot-spot cell using minimum load cell selection (MLCS) algorithm and deployed control flow of calls to define characteristic for hadoff region. we compared the performance of the random shedding approach with that of the proposed algorithm. The results of simulation show that MLCS algorithm minimizes the cal blocking rate under a high-density traffic compared to the random shedding scheme.

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Performance Analysis of the MPEG Video Multiplexer Considering Traffic Periodicity in Frame Level (프레임 단위의 트래픽 주기성을 고려한 MPEG 비디오 멀티플렉서의 성능 분석)

  • Kang, Jin-Kyu;Lie, Chang-Hoon
    • Journal of Korean Institute of Industrial Engineers
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    • v.22 no.3
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    • pp.387-398
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    • 1996
  • In this study the cell arrival processes from pre-buffer into multiplexer for MPEG(Motion Picture Experts Group) coding video sources are analyzed with consideration of the traffic periodicity in frame level. The analysis is performed by introducing the two arrival models, that is, periodic on/off source model and periodic uniform arrival model. Modulated $N^*D$/D/1 queueing system is utilized in periodic on/off source model, while ${\Sigma}{N_i}^*D_i$/D/1 queueing system is used in periodic uniform arrival model. The presented models are validated by comparing with computer simulations. Numerical results for periodic uniform arrival model are shown to be very accurate, but those of periodic on/off source model are shown to be inaccurate as the number of sources are increased.

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ASYMPTOTIC MAXIMUM PACKET SWITCH THROUGHPUT UNDER NONUNIFORM TRAFFIC

  • JEONG-HUN PARK
    • Management Science and Financial Engineering
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    • v.4 no.2
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    • pp.43-58
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    • 1998
  • Packet switch is a key component in high speed digital networks. This paper investigates congestion phenomena in the packet switching with input buffers. For large value of switch size N, mathematical models have been developed to analyze asymptotic maximum switch throughput under nonuniform traffic. Simulation study has also been done for small values of finite N. The rapid convergence of the switch performance with finite switch size to asymptotic solutions implies that asymptotic analytical solutions approximate very closely to maximum throughputs for reasonably large but finite N. Numerical examples show that non-uniformity in traffic pattern could result in serious degradation in packet switch performance, while the maximum switch throughput is 0.586 when the traffic load is uniform over the output trunks. Window scheduling policy seems to work only when the traffic is relatively uniformly distributed. As traffic non-uniformity increases, the effect of window size on throughput is getting mediocre.

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Traffic Grooming Algorithm for Maximizing Throughput in WDM Multi-Ring Networks (WDM 멀티링에서 전송효율을 최대화하기 위한 트래픽 그루밍 알고리즘)

  • Yoon, Seung-Jin;Lim, Chul-Soo
    • Journal of IKEEE
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    • v.15 no.2
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    • pp.157-163
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    • 2011
  • In this paper, novel traffic groomming algorithms are proposed with a primary goal for maximizing throughput in WDM Multi-ring networks. To achieve this goal, we design four network topologys that are ITG, STG, MTG, PMTG and simulate the throughput in uniform traffic environments. From this methods, we proposed novel traffic groomming algorithms to maximize throughput in WDM Multi-ring networks.

Comparative Performance Study of WDM Packet Switch for Different Traffic Arrival Approach

  • Reza, Ahmed Galib;Lim, Hyo-Taek
    • Journal of information and communication convergence engineering
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    • v.9 no.5
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    • pp.551-555
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    • 2011
  • Optical packet switching is a promising technology, which can integrate both data and optical network. In this paper, we present a comparative study of various traffic arrival approaches in WDM packet switches. The comparison is made based on packet loss rate and average delay under uniform and self-similar Pareto traffic. Computer simulations are performed in order to obtain the switch performance metrics. Study shows that burstiness of data traffic has a strong negative impact in the performance of WDM packet switches.