Abstract

This study uses regression analysis to evaluate long-run traffic management system performance. Three important traffic management systems in the Twin Cities metro area - Ramp Metering, Variable Message Signs (VMS), and Freeway Service Patrol (the Highway Helper Program) were evaluated with multiple regression models to predict link speed and incident rate. We find that ramp meters increase freeway link speed and reduce incident rate. Freeway Service Patrols increase link speed when incidents are present. The results for variable message signs are ambiguous. Document type: Part of book or chapter of book

Abstract

The performance and reliability of the Internet depend, in large part, on the operation of the underlying routing protocols. Today’s IP routing protocols compute paths based on the network topology and configuration parameters, without regard to the current traffic load on the routers and links. The responsibility for adapting the paths to the prevailing traffic falls to the network operators and management systems. This chapter discusses the modeling and computational challenges of optimizing the tunable parameters, starting with conventional intradomain routing protocols that compute shortest paths as the sum of configurable link weights. Then, we consider the problem of optimizing the interdomain routing policies that control the flow of traffic from one network to another. Optimization based on local search has proven quite effective in grappling with the complexity of the routing protocols and the diversity of the performance objectives, and tools based on local search are in wide use in today’s large IP networks. Document type: Part of book or chapter of book

Abstract

A risk-based fault tree analysis method has been developed at the Pacific Northwest Laboratory (PNL) for analysis of nuclear fuel cycle operations. This methodology was developed for the Department of Energy (DOE) as a risk analysis tool for evaluating high level waste management systems. A computer package consisting of three programs was written at that time to assist in the performance of risk assessment: ACORN (draws fault trees), MFAULT (analyzes fault trees), and RAFT (calculates risk). This methodology evaluates release consequences and estimates the frequency of occurrence of these consequences. This document describes an additional risk calculating code which can be used in conjunction with two of the three codes for transportation risk assessment. TRECII modifies the definition of risk used in RAFT (prob. x release) to accommodate release consequences in terms of fatalities. Throughout this report risk shall be defined as probability times consequences (fatalities are one possible health effect consequence). This methodology has been applied to a variety of energy material transportation systems. Typically the material shipped has been radioactive, although some adaptation to fossil fuels has occurred. The approach is normally applied to truck or train transport systems with some adaptation to pipelines and aircraft. TRECII ismore » designed to be used primarily in conjunction with MFAULT; however, with a moderate amount of effort by the user, it can be implemented independent of the risk analysis package developed at PNL. Code description and user instructions necessary for the implementation of the TRECII program are provided.« le Document type: Report

Abstract

The next big step in the evolution of the automotive industry is the introduction of electric vehicles (EV), however has associated limitations of autonomy and in conjunction with this limitation, extended charging times, very few points of charging and smart electricity grids very embryonic. In this context, is requires a very rigorous planning of daily use of the EV. Thus, this work presents an information system that aims to help the driver in the daily use of the EV in order to deal with the charging problem, minimizing the problem of anxiety to achive the objectives through the continuous monitoring of the autonomy of the vehicle and the timely submission of relevant information related to charging process, also allowing the storage the energy transactions for later analysis and further improvements. Similarly, given the limitations of the electrical distribution network and taking into account N simultaneous charging process a management system is proposed to deal with this problem, in order to limit the total power consumed in each moment. Fundação para a Ciência e a Tecnologia (FCT)