Search results for "Estimation"

Valuing Freight Transport Time using Transport Demand Modelling: A Bibliographical Review

2011

The value of time for freight transport is of major importance in infrastructure-related cost–benefit analysis and yet its study has been largely neglected when compared with its passenger counterpart. In fact, one of the attributes that could decide the profitability of a project is how much can be saved if freight vehicles use new infrastructure. Despite being the primary benefit of most investments in transport infrastructure, researchers have not yet reached agreement over either the size or the nature of the values of time that should be used when evaluating projects. This article provides a review of the estimation of freight value of time through transport demand modelling and extant…

Estimations comparées de trends logistiques

1980

Référence interne : 80029

2013

Abstract. It has become possible to retrieve the global, long-term trends of trace gases that are important to atmospheric chemistry, climate, and air quality from satellite data records that span more than a decade. However, many of the satellite remote sensing techniques produce measurements that have variable sensitivity to the vertical profiles of atmospheric gases. In the case of constrained retrievals like optimal estimation, this leads to a varying amount of a priori information in the retrieval and is represented by an averaging kernel (AK). In this study, we investigate to what extent the estimation of trends from retrieved data can be biased by temporal changes of averaging kernel…

Are there returns from university location in a state-funded university system?

2013

Abstract A location in an economically active, high-amenity region could in many ways be a significant advantage for a university and its students and thus could also be positively linked to students' subsequent earnings. Based on this hypothesis, the present study empirically examines the effect of university location choice on earnings in Finland, focusing on the following question: To what extent does the choice of university location explain the observed positive early-career earnings premium for students graduating from the Helsinki metropolitan area rather than from one of the nine other university cities? The results suggest that no positive average earnings premium exists for metro …

Urban runoff modelling uncertainty: Comparison among Bayesian and pseudo-Bayesian methods

2009

Urban stormwater quality modelling plays a central role in evaluation of the quality of the receiving water body. However, the complexity of the physical processes that must be simulated and the limited amount of data available for calibration may lead to high uncertainty in the model results. This study was conducted to assess modelling uncertainty associated with catchment surface pollution evaluation. Eight models were compared based on the results of a case study in which there was limited data available for calibration. Uncertainty analysis was then conducted using three different methods: the Bayesian Monte Carlo method, the GLUE pseudo-Bayesian method and the GLUE method revised by m…

D-Optimal Design for Parameter Estimation in Discrete-Time Nonlinear Dynamic Systems

2012

Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/296701 An optimal input design method for parameter estimation in a discrete-time nonlinear system is presented in the paper to improve the observability and identification precision of model parameters. Determinant of the information matrix is used as the criterion function which is generally a nonconvex function about the input signals to be designed. To avoid the locally optimizing problem, a randomized designmethod is proposed bywhich a globally optimizing test plan other than input signals may be obtained. Then the randomized design ca…

A Study of the Influence of Shadowing on the Statistical Properties of the Capacity of Mobile Radio Channels

2008

Article from the journal: Wireless Personal Communications The original publication is available at www.springerlink.com : http://dx.doi.org/10.1007/s11277-008-9545-7 This paper studies the influence of shadowing on the statistical properties of the channel capacity. The problem is addressed by using a Suzuki process as an appropriate statistical channel model for land mobile terrestrial channels. Using this model, exact solutions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the channel capacity are derived. The results are studied for different levels of shadowing, corresponding to diff…

Indicators for sustainable pedestrian mobility

2012

Pedestrians walk everyday to satisfy their basic necessities. They need an environment that reflects their requirements and expectations, in other words "liveable" as much as possible. So we should offer tools that could allow a complete and clear evaluation of the existing walking environment, taking into account both pedestrian requirements and urban environment schemes. To measure pedestrian mobility performance we usually use indicators, which measure performances and grant a quick estimation of progress. Indicators are universally acknowledged synthetic and standard parameters that should help policy makers gauge whether things are going in the right direction or not. They should be ou…

Velocity estimation in wideband mobile stations equipped with multiple antennas

2009

©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/VETECS.2009.5073907 A new method is proposed for estimating the velocity of wideband mobile stations (MSs) equipped with multiple antennas. The MS speed is determined using the well-known relationship between the direction-of-arrivals (DOAs) and the Doppler frequency shifts experienced by the mult…

2021

Abstract Reliable patient-specific ventricular repolarization times (RTs) can identify regions of functional block or afterdepolarizations, indicating arrhythmogenic cardiac tissue and the risk of sudden cardiac death. Unipolar electrograms (UEs) record electric potentials, and the Wyatt method has been shown to be accurate for estimating RT from a UE. High-pass filtering is an important step in processing UEs, however, it is known to distort the T-wave phase of the UE, which may compromise the accuracy of the Wyatt method. The aim of this study was to examine the effects of high-pass filtering, and improve RT estimates derived from filtered UEs. We first generated a comprehensive set of UE…