11,159 research outputs found

    Sharing with Caution: Managing Parking Spaces in Vehicular Networks

    Get PDF
    By exchanging events in a vehicular ad hoc network (VANET), drivers can receive interesting information while driving. For example, they can be informed of available parking spaces in their vicinity. A suitable protocol is needed to disseminate the events efficiently within the area where they are relevant. Moreover, in such a competitive context where each vehicle may be interested in a resource, it is crucial not to communicate that resource to each driver in the vicinity. Otherwise, those drivers would waste time trying to reach a parking space and only one of them would be fulfilled, which would lead to a poor satisfaction in the system. To solve this problem, we detail in this paper a reservation protocol that efficiently allocates parking spaces in vehicular ad hoc networks and avoids the competition among the vehicles. We have integrated our protocol within VESPA, a system that we have designed for vehicles to share information in VANETs. An experimental evaluation is provided, which proves the usefulness and benefits of our reservation protocol in both parking lots and urban scenarios. Besides, we present an in-depth study of the state of the art on this topic, that shows the interest and the originality of our approach

    Smart city services over a future Internet platform based on Internet of Things and cloud: the smart parking case

    Get PDF
    Enhancing the effectiveness of city services and assisting on a more sustainable development of cities are two of the crucial drivers of the smart city concept. This paper portrays a field trial that leverages an internet of things (IoT) platform intended for bringing value to existing and future smart city infrastructures. The paper highlights how IoT creates the basis permitting integration of current vertical city services into an all-encompassing system, which opens new horizons for the progress of the effectiveness and sustainability of our cities. Additionally, the paper describes a field trial on provisioning of real time data about available parking places both indoor and outdoor. The trial has been carried out at Santander’s (Spain) downtown area. The trial takes advantage of both available open data sets as well as of a large-scale IoT infrastructure. The trial is a showcase on how added-value services can be created on top of the proposed architecture.This work has been partially funded by the research project SmartSantander, under FP7-ICT-2009-5 of the 7th Framework Programme of the European Community. This work has been supported by the Spanish government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the project ADVICE “Dynamic provisioning of connectivity in high density 5G wireless scenarios” (TEC2015-71329-C2-1-R)

    The myth of domain-independent persistence

    Get PDF
    The frame problem can be reduced to the problem of inferring the non-existence of causes for change. This paper concerns how these non-existence inferences are made, and shows how many popular approaches lack generality because they rely on a domain-independent assumption of occurrence omniscience. Also, this paper shows how to represent and use appropriate domain-dependent knowledge in three successively more expressive versions, where the causal theories are deductive, non-monotonic, and statistical

    A Methodology for Assessing the Urban Supply of On-street Delivery Bays

    Get PDF
    The loading and unloading operations carried out by transport and logistics operators have a strong impact on city mobility if they are not performed correctly. If loading/unloading bays, i.e., delivery bays (DB), are not available for freight vehicle operations, operators may opt to double park or park on the sidewalk where there is no strong enforcement of these laws, with significant impact on congestion. This paper proposes a methodology for verifying and designing the number of delivery bays needed for freight vehicles for not interfere with cars or pedestrians. The methodology consists of two stages: in the first stage, an initial estimation is made using queueing theory. Subsequently, in the second stage, using such tentative scenario, in order to take into account the system stochasticity involving different entities, a discrete event simulation is performed to more realistically verify and upgrade (if necessary) the number of delivery bays to obtain the expected outcomes. The methodology was applied in the inner area of Santander (Spain). The study area was subdivided into 29 zones where the methodology was applied individually. The results indicated that none of these zones currently have an optimal number of delivery bays to satisfy demand. In some zones, there is an excess of delivery bays, although in most of them, there is a deficit which can cause significant impacts on traffic. The method proposed can be an effective tool to be used by city planners for improving freight operations in urban areas limiting the negative impacts produced in terms of internal and external costs

    Harmonizing Climate Change Mitigation and Adaptation in Transportation and Land-Use Planning in California Cities

    Get PDF
    Abstract: Recent extreme weather events in California—wildfires, drought, and flooding—make abundantly clear the need to plan effective responses to both the causes and the consequences of climate change. A central challenge for climate planning efforts has been identifying transportation and land-use (TLU) strategies that simultaneously reduce greenhouse gas emissions (“mitigation”) and adapt communities so that they will be less affected by the adverse impacts of climate change (“adaptation”). Sets of policies that collectively address both mitigation and adaptation are known as “integrated actions.” This study explores municipal climate planning in California to determine whether cities incorporate integrated actions into their plans, assess the potential drivers of conflict between mitigation and adaptation in municipal plans, and identify ways the State of California can help cities more effectively incorporate integrated actions. The study methods consisted of a detailed analysis of climate planning documents from 23 California cities with particularly long histories of climate planning, plus interviews with 25 local, regional, and state officials who work on municipal climate planning. The authors found that some cities did adopt packages of integrated actions, and, promisingly, two cities with recently updated climate plans explicitly focused on the need for integrated actions. However, most cities addressed climate mitigation and adaptation in separate efforts, potentially reducing synergies between the two types of action and even creating conflicts. Since the first generation of climate action plans focused primarily on mitigation of greenhouse gases (GHGs), adaptation strategies have not yet been effectively or fully combined into mitigation plans in many cities. Also, a cross-comparison of plan content and interview data suggests that cities often had sets of policies that could potentially create conflicts—mitigation policies that would undermine adaptation capacity, and vice versa. In addition, where a city did adopt integrated actions, these efforts are typically not labeled as such, nor do the policies appear within the same policy document. The study findings suggest promising steps that both municipal and state governments can take to support integrated TLU actions at the local level. For example, cities can proactively link the content in climate mitigation and adaptation plans—a process that will require building the capacity for cross-collaboration between the various departments in charge of developing, implementing, and monitoring climate-related plans. As for the state government, it can provide funding specifically for planning and implementing integrated actions, offer technical support to help municipalities adopt programs and projects that produce integrated mitigation and adaptation benefits, and fund research in the area of integrated actions

    A methodology for assessing the urban supply of on-street delivery bays

    Get PDF
    ABSTRACT: The loading and unloading operations carried out by transport and logistics operators have a strong impact on city mobility if they are not performed correctly. If loading/unloading bays, i.e., delivery bays (DB), are not available for freight vehicle operations, operators may opt to double park or park on the sidewalk where there is no strong enforcement of these laws, with significant impact on congestion. This paper proposes a methodology for verifying and designing the number of delivery bays needed for freight vehicles for not interfere with cars or pedestrians. The methodology consists of two stages: in the first stage, an initial estimation is made using queueing theory. Subsequently, in the second stage, using such tentative scenario, in order to take into account the system stochasticity involving different entities, a discrete event simulation is performed to more realistically verify and upgrade (if necessary) the number of delivery bays to obtain the expected outcomes. The methodology was applied in the inner area of Santander (Spain). The study area was subdivided into 29 zones where the methodology was applied individually. The results indicated that none of these zones currently have an optimal number of delivery bays to satisfy demand. In some zones, there is an excess of delivery bays, although in most of them, there is a deficit which can cause significant impacts on traffic. The method proposed can be an effective tool to be used by city planners for improving freight operations in urban areas limiting the negative impacts produced in terms of internal and external costs

    Evaluating the Effect of Smart Parking Technology on Campus Parking System Efficiency using Discrete Event Simulation

    Get PDF
    This study was conducted to investigate the effect of smart parking systems (SPS) on parking search times (PST) in large parking lots. SPSs are systems that disseminate real-time parking spot availability to drivers searching for parking. The literature review revealed discrete event simulation (DES) to be a suitable tool for studying the dynamic behavior in parking lots. The parking lot selected for data collection was a university parking lot with 234 spaces. The data collected included arrival rates, departure rates, the geometric properties of the parking lot, preferred parking search strategies, and driving speeds. Arena 13.9, by Rockwell Automation, Inc, was selected as the modeling software. The base model was built from observed parking search strategies (PSS) of drivers. The model was validated using a t-test for independent samples to compare the PSTs of the base model and actual parking lot. Once the base model was verified and validated, the logic was altered to reflect (PSS) (IV) with real-time parking availability (i.e. simulating the presence of an SPS). The PSTs (DV) for the base and experimental models were compared using a t-test for independent samples. It was found that SPSs reduce PSTs by an average of 11 seconds. This shows great potential for a multi-lot SPS that might save a larger amount of time and harmful vehicle emissions
    • …
    corecore