603 research outputs found
A two-stage route optimization algorithm for light aircraft transport systems
No full textThis paper presents a route optimization algorithm for light aircraft operating under visual flight rules. The problem aims at finding a minimum-duration, collision-free route in three spatial dimensions with possible aircraft maneuvers. The optimal route takes into account the aircraft kinodynamic characteristics and its interaction with external wind. A data processing approach is presented to recast the flying environment as a series of polyhedrons based on which a mixed-integer linear model is formulated. A two-stage route optimization model is then introduced to solve real-life instances. Computational experiments depict the efficiency of this approach.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and Logistic
The Impact of Collaborative Scheduling and Routing for Interconnected Logistics: A European Case Study
No full textInterconnected logistics system can play an important role towards having a more sustainable green freight transport. Recently, after introducing the concept of Physical Internet (PI), researchers have started to explore the opportunities and challenges that a collaborative and interconnected network could create in different aspects of the supply chain. In this research, we study the last mile delivery as well as vehicle dispatching problems under the assumptions of collaborative supply chain networks while assuming that modularized boxes are applied inside the network from the provider to the final customer. Our research aims at proposing a more efficient resource planning with the minimal number of empty vehicle movements running on roads that ultimately leads to decrease carbon dioxide emission. The assumptions have been tested and verified using real data coming from a major retail company in Europe.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and Logistic
Effect of Real-Time Truck Arrival Information on the Resilience of Slot Management Systems
No full textTraffic congestion is uncertain and undesirable in logistics and leads to arrival uncertainty at downstream locations engendering disruptions. This paper considers a loading facility that uses Truck Appointment System (TAS) for slot management and faces incoming truck arrival uncertainty due to traffic congestion. Due to the recent advancements in cyber-physical systems, we propose an adaptive system that uses the real-time truck Estimated Time of Arrival (ETA) data to make informed decisions. We develop an integer mathematical model to represent the adaptive behavior that determines the optimal reschedules by minimizing the average truck waiting time. We developed a simulation model of the adaptive system and reported the estimated benefits from our initial experiments.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and LogisticsTransport and Plannin
Gender differences in the evaluation of a risky technology
No full textResearch has been done on the gender differences in the evaluation of nanotechnology by Dutch TU Delft students. The research was executed using a questionnaire which was designed to examine if there are gender differences in the judgement of nanotechnology and if so, which variables play a significant role in this causal relations. Based on the factor analyses of the collected data, structural equation models (SEM) were estimated for the data of the whole sample, for the data of men and for the data of women. The analyses included the following 15 variables: gender, level of science education, studying nanotechnology, age, evaluation of nanotechnology, health and environmental effects, economical benefits, costs, level of trust in the government, level of trust in the industry’s concern with the environment, level of trust in the industry’s concern with safety, positive affect, negative affect, subjective knowledge, objective knowledge. The estimated SEMs showed that there is a significant gender difference in the evaluation of nanotechnology, as men evaluate nanotechnology more positive than women. This gender difference is largely explained by the variable on the expected effects of nanotechnology on health and environment. Other variables that have a significant effect on the evaluation of nanotechnology in the overall model are: age, gender, education, if the respondent has studied nanotechnology, trust in the industry’s concern with the environment. It was also found that the variable gender affects several relations between variables, meaning that the relation between these variables is different for men and women. The variables of which the direct relation with the evaluation of nanotechnology is affected by gender are ‘trust in the industry’s concern with the environment’, ‘expected costs’ and ‘studying nanotechnology’. The outcomes of this research suggest that it is essential to include women in the boards of the development of risky technologies. Women are for example less positive about the effects of nanotechnology on the health and environment, indicating that women pay more attention to the negative effects of the technology which makes them essential for responsible innovation. The results furthermore indicate that future research on the evaluation of risky technologies should take the underlying relations and variables into account because gender can influence the relations between the variables which results in different SEM’s for men and women.Technology, Policy and ManagementEthics/Philosophy of TechnologyMO
A Time-use Model for the Automated Vehicle-era
No full textAutomated Vehicles (AVs) offer their users a possibility to perform new non-driving activities while being on the way. The effects of this opportunity on travel choices and travel demand have mostly been conceptualised and modelled via a reduced penalty associated with (in-vehicle) travel time. This approach invariably leads to a prediction of more car-travel. However, we argue that reductions in the size of the travel time penalty are only a crude proxy for the variety of changes in time-use and travel patterns that are likely to occur at the advent of AVs. For example, performing activities in an AV can save time and in this way enable the execution of other activities within a day. Activities in an AV may also eliminate or generate a need for some other activities and travel. This may lead to an increase, or decrease in travel time, depending on the traveller’s preferences, schedule, and local accessibility. Neglecting these dynamics is likely to bias forecasts of travel demand and travel behaviour in the AV-era. In this paper, we present an optimisation model which rigorously captures the time-use effects of travellers’ ability to perform on-board activities. Using a series of worked out examples, we test the face validity of the model and demonstrate how it can be used to predict travel choices in the AV-era.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and Logistic
Spacematrix: Space, Density and Urban Form - revised edition
No full textSpacematrix explores the potential of urban density as a tool for urban planning and design.This revised and extended edition of Meta Berghauser Pont and Per Haupt’s 2010 volume includes an extensive analysis of the relations between density, urban form and performance – a prerequisite for understanding and successfully predicting the effects of specific designs and planning proposals. The density database that is an integral part of the book has been expanded and now includes 142 examples from five capitals in Europe as well as examples from Asia.Berghauser Pont and Haupt demystify the use of concepts such as ‘urbanity’, ‘compact city’ and ‘park city’ by challenging the reliability of such concepts and critically examining the possibility of redefining them through quantification using multiple density measures.Spacematrix is of interest to professionals working in the field of urbanism, such as architects, urban planners and designers, as well as developers, economists, engineers and policymakers. It also offers researchers a method to quantitatively describe urban form and connect this to a wide range of performances.OLD Urban Composition
Theoretical test for the work "Hinterland freight transportation replanning model under the framework of synchromodality".
No full textWe build a replanning model for hinterland freight transportation. To test the difficulties of solving the model, we test it with more theoretical cases. The dataset is shared on this open platform for the reviewer and readers to check
Modal wavefront correctors based on nematic liquid crystals
No full textModal wavefront correctors are active optical components for the compensation of aberrated optical wavefronts in a smooth and continuous way. They are traditionally represented by membrane and continuous faceplate deformable mirrors. This thesis is dedicated to the investigation and development of modal wavefront correctors based on nematic liquid crystals. The thesis introduces a new method for evaluating the average static correction performance of a wavefront corrector applied to compensation of random phase aberrations. Statistics of the random wavefronts are described by Kolmogorov's theory. The method allows a comparison of the static correction performances of different types of deformable mirrors and different actuator structures. A range of modal liquid crystal (LC) devices is considered, including adaptive spherical and cylindrical LC lenses and three different types of multi-element wavefront correctors. The research is focused on electro-optics of the devices, consideration of potentially useful control modes, development of algorithms of optimization and control, and alternative technologies for modal addressing of LCs. A control algorithm and software have been developed for a system for practical calibration of modal LC lenses. Feasibility of control using several degrees of freedom per actuator is demonstrated for both adaptive LC lenses and multi-element modal wavefront correctors. Two new approaches to forming of the modal-type phase profiles in LC layers are considered. The first one is based on spreading of the electric field in a thick dielectric substrate and the second one is based on a passive resistive network formed in a semiconductor silicon substrate. These approaches are illustrated with practically implemented devices. Comparison of the new technologies to a previously studied one is presented.Electrical Engineering, Mathematics and Computer Scienc
Assessing people travel behavior using GPS and open data to validate neighbourhoods characteristics
No full textWith the help of technologies such as GPS tracks, GIS and open data is now possible to study people travel behaviour in a new way. Nowadays, large datasets can be easily handled thanks to databases and better visualized using GIS. Moreover, the availability of GPS data, open data and VGI makes accessible a lot of new information, which was not obtainable before. This research is about the analysis of mobility patterns in different neighbourhoods in three cities in the Netherlands. The study is based on the validation of mobility theoretical performances by the actual performances measured through the analysis of GPS logs of households, who live in the neighbourhoods. A series of spatial indicators based on proximity, density and accessibility are computed in order to assess the theoretical performances of the neighbourhoods. To achieve this task, information about built environment characteristics and infrastructure networks is retrieved from OpenStreetMap, and other datasets. In the end the neighbourhoods are classified into five classes, according to the different levels of performances in terms of sustainable mobility. In such a way, it is possible to better understand the key factors that influence actual people travel patterns, providing policy makers with accurate information about the real movement of people.OLD Urban DesignOLD Department of GIS Technolog
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