Large Fork-Join Queues with Nearly Deterministic Arrival and Service Times

In this paper, we study an N server fork-join queue with nearly deterministic arrival and service times. Specifically, we present a fluid limit for the maximum queue length as [Formula: see text]. This fluid limit depends on the initial number of tasks. In order to prove these results, we develop extreme value theory and diffusion approximations for the queue lengths.

Traffic Simulation, Optimization and Evaluation of Adjacent Intersections Based on VISSIM Model

This paper mainly aims at alleviating the traffic congestion on urban roads and analyzes the traffic at adjacent intersections. First, the paper briefly introduced the VISSIM model, and then selected the traffic situation at the intersection of Weibin road and Fengcheng first road and the intersection of Weibin road and Fengcheng second road in Weiyang district of Xi’an city as research objects to simulate. Fanally, on the premise of basic meet the actual conditions, the optimization of channelization and signal timing at the intersection reduces the maximum queue length and the average stopping times of vehicles, so that the traffic of the section can run efficiently and smoothly, and provides an effective experiment for the optimization of the intersection.

Evaluation of the Operational Performance of Continuous Green T-Intersection under Different Levels of Congestion

The main objective of this paper is to evaluate and compare the operational efficiency of a conventional signalized T-intersection with an unconventional Continues Green T-intersection under different congestion levels. The analysis was performed using Synchro.8 micro-simulation software. A total of 48 hypothetical scenarios, 24 scenarios for each design, were created by changing the approach volumes and turning percentages on the major / minor intersecting roadways to reflect different levels of congestion that may occur on any urban intersection. Total intersection delay, Level of Service, maximum queue length and volume-to-capacity ratio (v/c) were the measures of effectiveness used for comparison purposes. These performance measures were selected because they demonstrated the overall efficiency of the intersection design. The simulation results showed that the Continuous Green T-intersection operates the best under stable traffic conditions and that it is not an effective solution for signalized T-intersections under heavy traffic volume.

Bid-Based Priority Signal Control in a Connected Environment: Concept

Though the loss of time is considered equivalent to opportunity loss, little research has been conducted in the field of signal control that accounts for individual differences in subjective opportunity loss. Because bids reflect the subjective valuation of opportunity loss, this paper introduces the concept of a bid-based priority signal control that accommodates indeterministic characteristics of queue formation in a connected environment and addresses several key elements of such a concept. Within this conception, drivers can bid for their desired signal indication. Based on these bids, an algorithm extends a green interval as long as the cumulative opportunity loss observed in stopped movements remains less than the value that would be lost through the termination of that green interval. The effects of this new type of control on user benefit and queueing delay were assessed using the asymmetric simple exclusion process. Simulation results showed that the bid-based priority signal control produced a greater subjective user benefit when measured in relation to a pre-timed control with a similar green interval. In addition, the bid-based priority signal kept the average maximum queue length relatively equal to its pre-timed equivalent. The bid-based priority signal control also balanced out the expected values of user benefit in conflicting movements. Bid-based signal priority control was recommended for further study to investigate the effects of bidding distributions on effectiveness and queue length in high-fidelity microsimulations.

Pengaruh Pelican Crossing terhadap Panjang Antrian dan Tundaan Kendaraan di Ruas Jalan Asia Afrika Kota Bandung (Hal. 18-27)

ABSTRAKPelican crossing merupakan jenis penyeberangan yang dioperasikan oleh penyeberang jalan yang bertujuan memberikan keselamatan kepada penyeberang. Tujuan dari penelitian ini adalah menentukan jenis penyeberangan dan mencari pemodelan tundaan dan panjang antrian akibat pelican crossing di jalan Asia Afrika Bandung. Data penelitian ini adalah frekuensi penyeberangan, jumlah penyeberang, jumlah kendaraan terhenti, arus lalu lintas, tundaan dan panjang antrian kendaraan. Analisis penentuan jenis penyeberangan menggunakan perhitungan PV2 dan analisis pemodelan tundaan dan panjang antrian menggunakan regresi linier berganda. Dari perhitungan PV2 didapatkan hasil PV2=2,49*109 yang berarti termasuk kepada jenis penyeberangan pelikan dengan lapak tunggu. Model yang mewakili hubungan antara panjang antrian (Y) dengan jumlah kendaraan terhenti (X1) dan frekuensi penyeberangan (X2) adalah Y=2,201 + 3,203X1 + 3,510X2. Model yang mewakili hubungan antara tundaan (Y) dengan variabel bebas yang sama adalah Y=0,709 + 2,656X1 + 7,645. Panjang antrian maksimum sebesar 78,072 meter dan tundaan maksimum sebesar 89,826 detik.Kata kunci: pelican crossing, panjang antrian, tundaanABSTRACTPelican crossing is a type of pedestrian cross which is operated by pedestrian with purpose is to give safety for the crosser. The aim of this study are to determine the type of crossing and find the model of delay and queue length because of pelican crossing at Asia Afrika Street Bandung. The data of this study are crossing frequency, amount of crossers, amount of stopped vehicle, traffic flow, delay and queue length vehicle. Analysis for the type of the crossing obtained by calculation of and analysis of model delay and queue length are use multiple regression. The result from the calculation of PV2 is PV2=2,49*109 which is the type of the crossing is pelican with protector. The represent model of relation between the queue length (Y) with amount of stopped vehicle and crossing frequency (X2) is Y=2,201 + 3,203X1 + 3,510X2.The represent model of relation between delay (Y) with same dependent variable is Y=0,709 + 2,656X1 + 7,645. The maximum queue length is 78,072 meters and the delay maximum is 89,826 seconds.Keyword: pelican crossing, the queue length, delay

A Modified Total Crossing Time Model of Bidirectional Pedestrians at Signalized Crosswalks

Since crosswalk width and pedestrian green time directly affect the safety of signalized crosswalks, modeling an exact total crossing time model to estimate those two variables is imperative. The total crossing time needed by a group of pedestrians to cross a signalized crosswalk contains the discharge time and the crossing time. The discharge time depends primarily on the maximum queue length, which is determined by pedestrian arrival rate, red interval, waiting position distribution, and the crosswalk width. Crossing time increases when interactions between bidirectional pedestrian flows become more serious. Thus, quantifying the impacts of the start-up process on the discharge time and the effects of the interactions on the crossing time is a prerequisite for optimizing the design of signalized crosswalks. This paper establishes a modified total crossing time model consisting of modified pedestrian discharge and crossing time. Discharge time is modeled by applying traffic wave theory, and crossing time is modeled based on drag force theory. The proposed models provide guidance for the design of crosswalk width and pedestrian green intervals.

Queuing Game Theory Based Optimal Routing Scheme for Heterogeneous Users over Space Information Networks

An optimal routing scheme in space information networks was presented to balance network loads for heterogeneous users. According to the competition among the nodes, the model was built based on queuing game theory. The virtual routing platform was in charge of resources allocation and route selection. It got user’s gain to decide which node the user joined in. Owning to the existing of heterogeneous users, an optimal admission fee needed to be obtained to avoid congestion. In our model, firstly, the whole welfare of the system was formulated. Then the optimal admission fee was calculated through maximizing the whole welfare. Meanwhile, the average maximum queue length was generated to set the buffer space of the node. At last, a routing factor was introduced into the route algorithm in order that the optimal routing could be selected by heterogeneous users. As a result, the system welfare reaches the maximum.