Document Server@UHasselt
(3.246 recursos)
Repository of the University of Hasselt containing publications in the fields of statistics, computer science, information strategies and material from the Institute for behavioural sciences.
Mostrando recursos 1 - 20 de 197
1.
A model for identifying and ranking dangerous accident locations: a case study in Flanders - BRIJS, Tom; VAN DEN BOSSCHE, Filip; WETS, Geert; Karlis, D.
These days, road safety has become a major concern in most modern societies. In this respect, the determination of road locations that are more dangerous than others (black spots or also called sites with promise) can help in better scheduling road safety policies. The present paper proposes a multivariate model to identify and rank sites according to their total expected cost to the society. Bayesian estimation of the model via a Markov Chain Monte Carlo approach is discussed in this paper. To illustrate the proposed model, accident data from 23,184 accident locations in Flanders (Belgium) are used and a cost...
3.
Frequency and Severity of Belgian Road Traffic Accidents Studied by State-Space Methods - HERMANS, Elke; WETS, Geert; VAN DEN BOSSCHE, Filip
In this paper we investigate the monthly frequency and severitiy of road traffic accidents in Belgium from 1974 to 1999. We describe the trend in the time series, quantify the impact of explanatory variables, and make predictions. We found that laws and concerning seat belts, speed, and alcohol have proven succesful. Furthermore, road safety increases with freezing temperatures while sun has the opposite effect, and precipitation and thunderstorms particularly influence accidents with light injuries. Economic conditions have a limited impact. State-space methodology is used throughout the analysis. We compared the results of this study with those of earlier research that...
4.
Ecological inference and spatial heterogeneity: an entropy-based distributionally weighted regression approach - PEETERS, Ludo; Chasco, C.
In this article we compare two competing approaches to ecological modelling using test data. The first approach is based on the "traditional" method of Ordinary Least Squares (OLS), assuming constancy of parameters across disaggregated spatial units (spatial homogeneity). The second (new) approach is based on the method of Generalised Cross-Entropy (GCE), assuming varying parameters (spatial heterogeneity). The latter approach is designated as entropy-based "distributionally weighted regression" (DWR).....
5.
Modelling and optimising the inland waterway network in Belgium - CARIS, An; JANSSENS, Gerrit; Macharis, C.
In this paper the main idea of my PhD research is described. We aim to analyze the operational performance of intermodal networks including inland navigation. The intermodal hinterland network of the port of Antwerp serves as the real-world application on our study. Characteristics of the inland waterway network in Belgium are discussed. From this description our research objectives are further formulated. The research methodology comprises three phases. The first phase of the research aims at gaining an insight into modelling techniques in the field of operations research applicable to intermodal transport. The second phase consists of designing a discrete event...
6.
Toenemend vermogen, topsnelheid en gewicht van auto's en de productaansprakelijkheid van de autoconstructeurs - De Mol, J; Lavrysen, L; VLASSENROOT, Sven
Binnen het onderzoeksveld verkeersveiligheid is er erg beperkt onderzoek naar het toenemend
vermogen, topsnelheid, gewicht, hoogte en breedte van voertuigen. Nochtans hebben
deze factoren een invloed op verkeersveiligheid en leefmilieu. Uit een vergelijkend onderzoek (1983, 1993, 1999, 2004) van de meest verkochte merken en
modellen in België wordt aangetoond dat wagens steeds maar meer vermogen hebben,
steeds zwaarder worden, steeds sneller kunnen rijden. Het toenemende vermogen en snelheid
staat haaks op de pogingen om de snelheid van voertuigen onder controle te houden. Alhoewel
de snelheidsmaxima in Europa meestal niet boven 130 km/uur gaan, worden wagens
aangeboden met een vermogen en topsnelheid die dit ruim overschrijden. Deze hoge...
7.
Interpreting Logistical Performances using Trellis displays - DE VOS, Daniella; Van Hoof, K; Van Landeghem, H
For the past two years we are working on benchmarking performance data to explore the potential
value of knowledge discovery methods in databases for information access. Many of these data are still very
under analysed. In particlular we are interested in exploiting machine-learning systems using an inductive
supervised approach to predict a companys logistical performance related to its past financial state.
Benchmarking assessments produce a broad heterogeneous collection of data difficult in analysing and
which goes beyond the classical framework in providing measurable information. So there is a need to
describe more complex units or concepts. There is a need for carriers of aggregated information and...
8.
The Application of Uninorms in Importance-Performance Analysis - DEPAIRE, Benoit; Van Hoof, K; WETS, Geert
In the field of marketing, Importance-Performance Analysis is a useful technique for evaluating the elements of a marketing program. The importance dimension of this technique is often determined in a regression based approach. However, this approach has certain problems and limitations. A new approach, based on uninorms, is suggested. This article shows that the uninorm approach possesses several strengths for this type of analysis and matches particularly well with the customer satisfaction theory.
9.
Describing the evolution in the number of highway deaths by a decomposition in exposure, accident risk and fatal risk - HERMANS, Elke; WETS, Geert; VAN DEN BOSSCHE, Filip
The general purpose of this research is to improve the insight in road safety on Belgian
highways by means of a layered model. In this study, the monthly number of persons killed
on highways in Belgium will be decomposed in three parts, namely exposure, accident risk
and fatal risk. The evolution in these three dimensions will be investigated separately. More
specifically, for each dimension a descriptive and explanatory analysis will reveal the most
optimal unobserved components model. The separate analysis of each dimension may reveal
different underlying developments. We will study the impact of meteorological, socioeconomic,
legislative and calendar factors on exposure, accident risk and fatal risk....
10.
The Impact of Weather Conditions on Road Safety Investigated on an Hourly Basis - HERMANS, Elke; BRIJS, Tom; Stiers, T; Offermans, C
In this paper we investigate the impact of several weather conditions on the hourly number of crashes in the Netherlands during 2002. The impact of 17 climatic factors, belonging to the categories wind, temperature, sunshine, precipitation, weather image and visibility is quantified and compared with results from other research. The following could be concluded: an increase in maximum wind gust causes an increase in the number of crashes. Global radiation and sunshine duration both have a significant negative impact on road safety. Of all categorical weather indicators, presence of precipitation had the most significant impact. Moreover, the impact of precipitation...
11.
Impact of 30 km/h zone introduction on vehicle exhaust emissions in urban areas - Int Panis, L; BECKX, Carolien; Broeckx, Steven
One of the most common traffic management schemes used in Belgium today is the conversion of entire districts, streets or street sections into 30 km/h zones. This is usually done in residential areas where the previous speed limit was 50 km/h. These measures, aimed at increasing traffic safety, are usually seen or even promoted as beneficial to the environment because of reduced fuel consumption and emissions. These claims however are unsubstantiated and stem from the believe that speed reduction measures in urban areas have similar benefits as those on highways. In contrast to this popular believe, wide spread emission estimation...
12.
Urban air quality and traffic in flemish cities - Int Panis, L; BECKX, Carolien; Van Poppel, M
Op 26 juni 2005 stelde minister Peeters de modellen CAR en MOBILEE voor aan de
pers en de Vlaamse steden en gemeenten. Met het CAR-model dat het Vlaams Gewest
gratis aanbiedt kunnen steden en gemeenten voortaan zelf een eerste ruwe inschatting
maken van de effecten van lokaal verkeer op de luchtkwaliteit in een straat. CAR werd
ontwikkeld in het zog van het strategisch VITO-project MOBILEE (een samentrekking
van mobiliteit en leefbaarheid). Tussen 2002 en 2005 heeft een multidisciplinair team
onder leiding van VITO gewerkt aan de ontwikkeling van de methodologie en de
opbouw van het MOBILEE model. Op een systematische en consistente manier worden
alle milieu-effecten van een...
13.
The optimization of activity-travel sequences by means of reinforcement learning - JANSSENS, Davy; Lan, Y; WETS, Geert; Chen, G
Given a sequence of activities and transport modes,
this paper evaluates the use of a Reinforcement
Machine Learning technique. The technique simulates
time and location allocation for a given set of
sequences and enables the prediction of a more
complete and consistent activity pattern. A computer
code has been established to automate the process and
has been validated on empirical data.
14.
Allocating time and location information to activity-travel patterns through reinforcement learning - JANSSENS, Davy; Lan, Y.; WETS, Geert; Chen, G.
Given a sequence of activities and transport modes, for which a framework has been provided
in previous work, this paper evaluates the use of a Reinforcement Machine Learning
technique. The technique simulates time and location allocation for these predicted sequences
and enables the prediction of a more complete and consistent activity pattern. The main
contributions of the paper to the current state-of-the art are the allocation of location
information in the simulation of activity-travel patterns as well as the application towards
realistic empirical data, the non-restriction to a given number of activities and the
incorporation of realistic travel times. Furthermore, the time and location allocation problem
were treated...
15.
A two-dimensional extension of Allen's temporal logic as an intelligent support for the solution of packing problems - JANSSENS, Gerrit
Inland vessels move goods along canals and rivers and
they visit ports. Due to tides on the rivers, the vessels
make use of locks to enter ports or canals. From a port
management point of view, a fast access to and from
the port and high utilisation of a lock are important
objectives. The policy to access the lock works as
follows. Vessels wait in front of the lock. A port
administrator assigns a place in the lock based on the
knowledge of the vessels dimensions. As such, there
is no FIFO-discipline, but a group-FIFO-discipline,
i.e. if n vessels are allowed to the lock, they are the
first n vessels in...
16.
Dynamic activity-travel diary data collection using a GPS-enabled personal digital assistant - KOCHAN, Bruno; BELLEMANS, Tom; JANSSENS, Davy; WETS, Geert
Activity-based transportation models have set the standard for modelling
travel demand for the last decade. It seems common practice nowadays to collect the
data to estimate these activity-based transportation models by means of activitytravel
diaries. This paper presents a general functional framework of an advanced
activity-travel diary data collection application to be deployed on a GPS-enabled
personal digital assistant (PDA). The different modules, which are the building
blocks of the application, will be scrutinized as well.
17.
Analysing success criteria for ict projects - Milis, K.; VANHOOF, Koen
Since the 1960's many authors accepted the triple constraints (time, cost, specification) as
a standard measure of success and this still appears to be extremely important in
evaluating the success of ICT (information communication technology) projects.
However, an ICT project cannot always be seen as a complete success or a complete
failure. Moreover, the parties involved may perceive the terms success or failure
differently.
A quasi-experiment (gaming) was developed in order to determine the measures for
success used by the different parties involved to judge an ICT project. The results of this
quasi experiment were analysed using aggregation theory and validated by probabilistic
feature models. In general the figures...
18.
Aiming for parsimony in the sequential analysis of activity-diary data - MOONS, Elke; WETS, Geert
This paper aims at a better understanding in the impact of simplification in a sequential analysis of activity-diary data using a feature selection method. To this effect, the predictive performance of the Albatross model, which incorporates nine different facets of activity-travel behaviour, based on the original full decision trees is compared with the performance of the model based on trimmed decision trees. The more parsimonious models are derived by first using a feature selection method to determine the irrelevant variables which are then left out of the further model building process. The results indicate that significantly smaller decision trees can...
19.
Setting up a continuous panel for collecting travelling information: discussion on methodological issues - MOONS, Elke; WETS, Geert
Modelling travel behaviour has always been a major area of concern in transportation research. Since
1950, due to the rapid increase in car ownership and car use in Western Europe and in the US;
several models of transport mode, route choice and destination have been used by transportation
planners. Some drawbacks of these first models are clearly the focus on individual trips, where the
interrelationships (spatial, temporal, intra-household) between trips and their characteristics are
ignored. This clearly shows why household travel data is a critical component of the travel-demand
forecasting process. The data are typically generated through a household-based survey in which a
sample of the population...
20.
A Solution Method for the Time Slot Assignment Problem in SS/TDMA Systems with Intersatellite Links - Nyambo, B.M.; JANSSENS, Gerrit
The time slot assignment problem (TSAP) is considered in a cluster of satellite-switched time-division multiple access (SS/TDMA) satellite systems with inter-satellite links. The TSAP is formulated as a graph coloring problem and leads to an integer programming formulation. Efforts are made to solve the problem by solving continuous linear programming methods and by rounding continuous values as integer optimal values. The interactive solution approach is satisfactory for real world problems.
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