Diffusion approximations and associated heavy-traffic Emit theorems have now become basic tools of queuing theory; e.g., see Gelenbe and Mitrani [3, Chapter 4], Kleinrock [8, Chapter 2]," Newell [12, Chapter 6] and references there. Under heavy-traffic condiuons, diffusion approximations are identified and justified by the heavy-traffic limit theorems: the diffusion process is obtained as the l...

We develop a diffusion approximation for the queue-length stochastic process in the G/GI/n/m queueing model (having a general arrival process, independent and identically distributed service times with a general distribution, n servers, and m extra waiting spaces). We use the steady-state distribution of that diffusion process to obtain approximations for steady-state performance measures of th...

Absfrucf -Retransmission policies are presented for the decentralized control of a multiaccess packet-switched broadcast channel. The policies have a simple recurSiYe form yielding a Markov description of the system. Finite average delay is achieved for an infinite-population Poisson arrival model for any rate X < e ’ . It is proposed that the goal of retransmission policies should be to...

Based on a unified analysis of both pure and slotted ALOHA systems, a new control algorithm for ALOHA systems is proposed. A feature of great practical importance is the algorithm’s automatic adjustment to changes in average traffic intensity or the (finite or infinite) number of active stations in the system. In addition, the algorithm has a low-complexity implementation. Computer simulations,...

Network clustering algorithms are typically based only on the topology information of the network. In this paper, we introduce traffic as a quantity representing the intensity of the relationship among nodes in the network, regardless of their connectivity, and propose an evolutionary clustering algorithm, based on the application of genetic operators and capable of exploiting the traffic infor...

Ji introduced his team’s workload prediction model and scheduling method for the purpose of isolating the performance of user traffic from system background work. He first introduced the tiered storage system and then explained that scheduling background work may flush out the user working set in the fast tier and therefore impact the performance of user traffic. Then he showed how their Markov...

Direct video measurements of surface street truck traffic at eleven intersections and line segments in communities adjacent to southern California ports document that volumes of portrelated trucks often reach 400-600 per hour for several hours, immediately upwind of ‘sensitive’ land uses such as schools, open-field parks and residences. The diurnal fluctuation of trucks on surface streets varie...

Driving simulators are used to conduct experiments on driver behavior, road design, and vehicle characteristics, etc. The results of the experiments often depend on traffic conditions. One example is the evaluation of cellular phones and how they affect driving behavior. It is clear that the ability to use phones when driving depends on traffic intensity and composition, and that realistic expe...

By applying visual analytics techniques to vehicle traffic data, we found a way to visualize and study the relationships between the traffic intensity and movement speed on links of a spatially abstracted transportation network. We observed that the traffic intensities and speeds in an abstracted network are interrelated in the same way as they are in a detailed street network at the level of s...

Data on vehicle operating conditions have been recorded by a specially equipped car. while circulating through Naples on several typical routes. during rush hours. Traffic was defined in terms of parts of movements between two consecutive stops ("kinematic sequences"). characterized by a number of kinematic variables. such as mean velocity. driving and idling time. gear ratio. number of peaks. ...