Abstract

This chapter presents an overview of changes in transport taxation in European countries to promote more sustainable transport. A number of changes in the framework of car taxation have resulted in some useful environmental gains. However, these changes are limited because the transport tax system has been designed to produce a substantial income from internal-combustion-engine vehicles in an easily administered form. A major restructuring of transport taxation is required to fully address a different goal – that of stimulating improvements to environmental performance. A generalised road user charging-based system could be the way forward. Such a system is now seen by several European countries and some USA states as the transport taxation regime for the 21st century. \\ud \\ud Tax regime change is emerging onto the transport policy agenda as a vital long-term strategy. Largely by default, transport policy-makers are coming to realise that road taxation regime change is inevitable if traffic and congestion management is to be a reality. The way we taxed vehicles and fuel in the 20th century is simply not appropriate for the transport challenges we face today. Document type: Part of book or chapter of book

Abstract

The assessment of uninterrupted traffic flow is traditionally based on empirical methods. We develop some analytic queueing models based on traffic counts and we model the behavior of traffic flows as a function of some of the most relevant determinants. These analytic models allow for parameterized experiments, which pave the way towards our research objectives: assessing what-if scenarios and sensitivity analysis for traffic management, congestion control, traffic design and the environmental impact of road traffic (e.g. emission models). The impact of some crucial modelling parameters is studied in detail and links with the broader research objectives are given. We illustrate our results for a highway, based on counted traffic flows in Flanders.

Abstract

Schemes described in the literature on network congestion management are in general based on queue management. Also it is widely accepted that Poisson model is not sufficient to characterize the traffic in current Internet. With this in view, in this paper, an attempt has been made by proposing a modified RED (random early detection) algorithm for traffic congestion management in IP networks with self-similar input. "We first present the basic scheme of RED as proposed by Floyd et.al., for the Poisson input model, and then explain the modification to the algorithm that we propose for a self similar IP traffic input. We take into consideration the probability values corresponding to the average queue lengths for computing the marking/dropping probability. Verification of the equation proposed vis-a-vis that of Floyd has been done by taking simulated values available for self-similar traffic. Results are tabulated and graphically shown. It has also been shown that under certain conditions, our modified equation for the marking probability, reduces to the one proposed by Floyd.

Abstract

Distributed energy resources (DERs), like electric vehicles (EVs), can offer valuable services to power systems, such as enabling renewable energy to the electricity producer and providing ancillary services to the system operator. However, these new DERs may challenge the distribution grid due to insufficient capacity in peak hours. This paper aims to coordinate the valuable services and operation constraints of three actors: the EV owner, the Fleet operator (FO) and the Distribution system operator (DSO), considering the individual EV owner’s driving requirement, the charging cost of EV and thermal limits of cables and transformers in a distribution grid capacity market framework. Firstly, a theoretical market framework is described. Within this framework, FOs who represent their customer’s (EV owners) interests will centrally guarantee the EV owners’ driving requirements and procure the energy for their vehicles with lower cost. The congestion problem will be solved by a coordination between DSO and FOs through a distribution grid capacity market scheme. Then, a mathematical formulation of the market scheme is presented. Further, some case studies are shown to illustrate the effectiveness of the proposed solutions.

Abstract

In this paper, we discuss employing a server in a router, the architecture of which is based on policy, for congestion management of IP traffic in Diffserv networks. We exploit the congestion information and employ that information to manipulate the network level parameters to adapt the traffic according to the current congestion state of the network. The congestion monitors interact with the policy server, which, depending on the network state, decides the policy/rules that should be enforced by the Diffserv network. The implementation of the selected policies typically leads to accepting, remarking or dropping the IP traffic packets entering the network. We have also indicated how these modules could functionally be used to generate and store appropriate rules based on policies for congestion management. Since the system will now be rule based, there is a need for policing action to monitor traffic and enforce these rules when congestion sets in, and we propose mobile agents accomplishing this job. Index Terms: Quality of service, IP Networks Congestion Management, Self-similar input, Policy based rules, Mobile Agents.

Abstract

In an IP network, if the source rates are increased beyond the service rates of the routers, then queues of packets waiting to be routed at the buffers, build up and exceed the buffering capacity of these routers leading to packets getting dropped. This results in low throughput and congestion collapse. In such networks, an AQM mechanism manages queue lengths in buffers and enables the end-systems to react to such losses by reducing their packet rate, avoiding severe congestion. Random Early Detection (RED) is one of the first AQM mechanisms to be used to avoid congestion in this manner. In this paper, the existing Normal and Gentle RED algorithms of Floyd as well as the justification for the proposed modified exponential RED algorithm have been discussed along with the results obtained on the functioning of the algorithms. Functioning of the algorithm proposed has also been tested using ns2 Simulator.

Abstract

Schemes described in the literature on network congestion management are in general based on queue management. Also it is widely accepted that Poisson model is not sufficient to characterize the traffic in current Internet. In this paper, we present the details of some simulation studies carried out on an alternate RED (random early detection) algorithm for traffic congestion management in IP networks having self similar input. We first discuss the basic scheme of normal as proposed by Floyd et al., for the Poisson input model, and then explain a new AQM proposed by us. Our modification to the RED algorithm takes into consideration probability values corresponding to the average queue lengths for computing the marking/dropping probability. Verification of the algorithms proposed vis-a-vis that of Floyd as well as the ones proposed by us, has been done by simulating self-similar traffic. Results of the verification have been discussed in the paper