Priority Parameters Research Articles

Theoretical approach to selection of basic parameters for double-purpose vehicles

Since multipurpose vehicles relate both to transport and traction classes of machines, the approaches to selecting values of their main parameters are different. According to a new method of determining basic characteristics of modifications, a vehicle should he considered as a truck-trailer system. By analysis of the forces acting on the system, design relationships for defining the rational values for models of double-purpose vehicles families are found. The priority parameters are maximum engine speed in the typical operating conditions and external resistance values to be overcome for the transport and traction-transport vehicles, and maximum hook power and hook force for the traction modifications.

A Pseudo-Bayesian ALOHA algorithm with mixed priorities

In reservation-based multiple access protocols, before obtaining a contention-free access to the channel, a mobile terminal must wait for its request packet to be successfully sent to the base station. A pseudo-Bayesian ALOHA algorithm with multiple priorities is proposed in this paper to reduce the waiting time of delay sensitive request packets in a multimedia environment. Packets are transmitted in each slot according to a transmission probability based on the channel history and a priority parameter assigned to their respective priority class. An adaptation of the slotted protocol to the framed environment proposed for wireless ATM is also described. Simulation results are presented to show that the protocol offers a significant delay improvement for high priority packets with both Poisson and self-similar traffic while low priority packets only experience a slight performance degradation.

Comparison of statistical procedures in analytic hierarchy process using a ranking test

Several statistical procedures for estimation of the priority parameters in the setup of the Analytic Hierarchy Process (AHP) exist in the literature. The purpose of this article is to make appropriate comparisons of such statistical methods. Pairwise comparison matrices are simulated using different statistical distributions of the error part used in the procedures. Priority parameters are estimated for each simulated pairwise comparison matrix using the method suggested. Standard nonparametric statistical procedures are applied to check whether the order of the priority estimates is consistent with that of their parameter values irrespective of the choice of particular statistical procedure. Statistical procedures based on the reciprocal matrices are also compared with the eigenvalue method.

Binomial-gated service: a method for effective operation and optimization of polling systems

The binomial-gated service, designed for cyclic polling systems, is proposed as a new service method. The important properties of this method are: (1) it allows one to prioritize the system queues using a set of priorities, and (2) it is mathematically analyzable. The method can be implemented in the token ring network and in many other communications systems. The nonsymmetric cyclic-polling system with binomial-gated service is analyzed and equation sets are derived from which the expected delay figures can be calculated numerically. A pseudoconservation law for nonsymmetric systems and a closed-form mean-delay expression for fully symmetric systems are derived as well. The effect of the priority parameters on the system performance is demonstrated in numerical examples. >

Comparative performance of voice/data local area networks

Using simulation, a network-independent framework compares the performance of contention-based Ethernet and two contention-free round-robin schemes, namely Expressnet and the IEEE 802.4 token bus. Two priority mechanisms for voice/data traffic on round-robin networks are studied: the alternating-rounds mechanism of the Expressnet, and the token rotation timer mechanism of the token bus, which restricts access rights based on the time taken for a token to make one round. It is shown that the deterministic schemes almost always perform better than the contention-based scheme. Design issues such as the choice of minimum voice packet length, priority parameters, and voice encoding rate are investigated. An important aspect that is noted is the accurate characterization of performance over a wide region of the design space of voice/data networks.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>