Search results for "GEM"
showing 10 items of 19240 documents
Automatic Identification System data - potential resource for marine vessels drift studies in the Baltic Sea
2020
Automatic Identification System (AIS) has been employed for increasing the safety at the sea. Nowadays general information about the marine traffic can be tracked in operational mode using www.marinetraffic.com web portal. Additional information can be purchased for commercial and research purposes. Our study highlights a possibility to study the drift using an additional information available at www.marinetraffic.com - selected data on vessel position during its status “not under command”, which corresponds to the drifting vessels. Trajectories of the drift from AIS have been compared with mathematically modeled point-wise drifter paths. Copernicus Marine Environmental Monitoring Service's…
Impact of decision horizon on post-prognostics maintenance and missions scheduling: a railways case study
2021
International audience; In this paper, we propose a study of the decision horizon duration for rolling stock mission assignment and maintenance planning in a prognostics and health management (PHM) context. The aim is to determine the best decision horizon duration that allows the con- struction of a suitable schedule that assigns railway vehicles to missions and integrates required maintenance operations accord- ing to the current and future health of the vehicles. A genetic algorithm is used to minimize the overall cost of the joint schedule as a function of the decision horizon. The results are compared to three proposed heuristics to study the influence of the resolution method on the d…
The facility location problem with capacity transfers
2020
Abstract This paper explores the concept of capacity transfer in the context of capacitated facility location problems. This is accomplished by assuming that facilities with surplus capacity/production can cooperate with those facing shortage by transferring part of that capacity/production. Such a transfer incurs a cost that nonetheless may be compensated by savings both in the installation costs and in the distribution costs. Mixed-integer mathematical programming models are proposed for the problem. A distinction is made between the case in which the triangle inequality holds for the transfer costs and the case in which it does not. We present compact models, which are enhanced with vali…
Some personal views on the current state and the future of locational analysis
1998
In this paper a group of participants of the 12th European Summer Institute which took place in Tenerife, Spain in June 1995 present their views on the state of the art and the future trends in Locational Analysis. The issues discussed include modeling aspects in discrete Location Theory, the influence of the distance function, the relation between discrete, network and continuous location, heuristic techniques, the state of technology and undesirable facility location. Some general questions are stated regarding the applicability of location models, promising research directions and the way technology affects the development of solution techniques.
‘Tool port’ to ‘landlord port’: a game theory approach to analyse gains from governance model transformation
2018
This study investigates potential port users’ surplus and terminal operators’ profits due to transforming port governance from the ‘tool port’ model to the ‘landlord port’ model. Although the landl...
From bus to tramway: Is there an economic impact of substituting a rapid mass transit system? An empirical investigation accounting for anticipation …
2018
Abstract Hedonic pricing models and price equations have been extensively used to retrieve the implicit prices of urban externalities through real estate markets. Many applications have been devoted to investigating the impact of new mass transit systems, such as rail infrastructures. However, the implementation of such infrastructures usually takes some time and markets can react with an anticipation effect that can vary according to the different development phases. Moreover, the impact may be different if it acts as a substitute to existing rapid transit services. This paper focuses on the impact of substituting bus rapid transit (BRT) for light rail transit (LRT) services, taking into a…
Messages beyond the phone: Processing variable message signs while attending hands-free phone calls.
2021
We examined the effects of different types of cognitive distraction coming from a hands-free phone conversation on the processing of information provided by variable message signs (VMS), on driving performance indicators, and on a physiological index of mental effort (heart rate). Participants drove a route in a driving simulator and had to respond to VMS messages under three conditions: no-distraction, visuospatial distraction (attending phone calls with questions inducing visuospatial processing), and conceptual distraction (attending phone calls with questions requiring semantic memory). Results showed more errors responding to VMS messages in the visuospatial distraction condition. In a…
Effectiveness and user acceptance of infotainment-lockouts: A driving simulator study
2019
Abstract Lockout is a system-initiated distraction mitigation strategy that renders certain features of in-vehicle information systems (IVISs) non operable while the vehicle is in motion. The aim of this driving simulator study was to examine the influence of lockouts on driving performance and user acceptance. Overall, 52 participants performed six tasks with fully unlocked, partially locked, and completely locked IVIS. Within a repeated-measures design, we assessed user acceptance. As participants were free to decide where to conduct a secondary task, we could only analyse driving performance of 26 drivers. After each driving section, the participants rated the respective system with resp…
Does higher technical efficiency induce a higher service level? A paradox association in the context of port operations
2020
Abstract Researchers and practitioners are benchmarking technical efficiency of ports and exploring the drivers of high efficiency. Paradoxically, this study argues that high technical efficiency (TE = 1) is not always essential, but an optimal level needs to be achieved while balancing the port service level. This study applies data envelopment analysis (DEA) and free disposal hull (FDH) methods to perform efficiency rankings of 38 container terminals from 17 different ports in 12 Asian countries. Four terminals are technically efficient (TE = 1) in all frontier approaches, thereof one Bangladeshi, one Chinese, one Indian and one Vietnamese. Furthermore, this study presents a case study co…
GIS Infomobility for Travellers
2016
Geographical Information Systems (GIS) are essential systems to support decisions on territorial and environmental aspects. But they not always have been properly used for this purpose. Only in recent years GIS have been getting better used for the planning, management and control of the territory. The application of GIS to the transport sector has become relevant both for management and decision-making in support of Public Administration (PA) and citizens. GIS are particularly useful for roads and routing graphs management capabilities as well as for searching the most suitable path. The results achieved in this research activity aimed to evaluate different road graphs, proprietary and fre…