11,991 research outputs found
Developing and Deploying a Taxi Price Comparison Mobile App in the Wild: Insights and Challenges.
As modern transportation systems become more complex, there is need for
mobile applications that allow travelers to navigate efficiently in cities. In
taxi transport the recent proliferation of Uber has introduced new norms
including a flexible pricing scheme where journey costs can change rapidly
depending on passenger demand and driver supply. To make informed choices on
the most appropriate provider for their journeys, travelers need access to
knowledge about provider pricing in real time. To this end, we developed
OpenStreetcab a mobile application that offers advice on taxi transport
comparing provider prices. We describe its development and deployment in two
cities, London and New York, and analyse thousands of user journey queries to
compare the price patterns of Uber against major local taxi providers. We have
observed large heterogeneity across the taxi transport markets in the two
cities. This motivated us to perform a price validation and measurement
experiment on the ground comparing Uber and Black Cabs in London. The
experimental results reveal interesting insights: not only they confirm
feedback on pricing and service quality received by professional drivers users,
but also they reveal the tradeoffs between prices and journey times between
taxi providers. With respect to journey times in particular, we show how
experienced taxi drivers, in the majority of the cases, are able to navigate
faster to a destination compared to drivers who rely on modern navigation
systems. We provide evidence that this advantage becomes stronger in the centre
of a city where urban density is high
Adoption of vehicular ad hoc networking protocols by networked robots
This paper focuses on the utilization of wireless networking in the robotics domain. Many researchers have already equipped their robots with wireless communication capabilities, stimulated by the observation that multi-robot systems tend to have several advantages over their single-robot counterparts. Typically, this integration of wireless communication is tackled in a quite pragmatic manner, only a few authors presented novel Robotic Ad Hoc Network (RANET) protocols that were designed specifically with robotic use cases in mind. This is in sharp contrast with the domain of vehicular ad hoc networks (VANET). This observation is the starting point of this paper. If the results of previous efforts focusing on VANET protocols could be reused in the RANET domain, this could lead to rapid progress in the field of networked robots. To investigate this possibility, this paper provides a thorough overview of the related work in the domain of robotic and vehicular ad hoc networks. Based on this information, an exhaustive list of requirements is defined for both types. It is concluded that the most significant difference lies in the fact that VANET protocols are oriented towards low throughput messaging, while RANET protocols have to support high throughput media streaming as well. Although not always with equal importance, all other defined requirements are valid for both protocols. This leads to the conclusion that cross-fertilization between them is an appealing approach for future RANET research. To support such developments, this paper concludes with the definition of an appropriate working plan
Time Slot Management in Attended Home Delivery
Many e-tailers providing attended home delivery, especially e-grocers, offer narrow delivery time slots to ensure satisfactory customer service. The choice of delivery time slots has to balance marketing and operational considerations, which results in a complex planning problem. We study the problem of selecting the set of time slots to offer in each of the zip codes in a service region. The selection needs to facilitate cost-effective delivery routes, but also needs to ensure an acceptable level of service to the customer. We present two fully-automated approaches that are capable of producing high-quality delivery time slot offerings in a reasonable amount of time. Computational experiments reveal the value of these approaches and the impact of the environment on the underlying trade-offs.integer programming;vehicle routing;continuous approximation;e-grocery;home delivery;time slots
Agent-based simulation framework for the taxi sector modeling
Taxi services account for a significant part of the daily trips in most cities around the world. These services are regulated by a central authority, which usually monitors the performance of the taxi services provision and defines the policies applied to the taxi sector. In order to support policy makers, fleet managers and individual taxi drivers, there is a need for developing models to understand the behavior of these markets. Most of the models developed for analyzing the taxi market are based on econometric measurements and do not account for the spatial distribution of both taxi demand and supply. Only few simulation models are able to better understand the operational characteristics of the taxi market. This paper presents a framework for the development of agent based taxi simulation models. It is aimed at assessing policy makers, taxi fleet managers and individual drivers in the definition of the optimum operation mode and the number of vehicles.Peer ReviewedPostprint (published version
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Informatisation of transport process using GPS navigation system
Nowadays, internal business processes are one of the crucial factors of firms’ competitive advantage achievement, which is becoming increasingly important, not only on local but also on global markets. Firms’ performance improvement depends to a large extent on its flexibility, adjustability and especially ability to manage internal business processes. Hence, use of information technology is among the fundamental elements of business process change, which not only improve competitiveness but also assure long term development and growth of the firm. For all these reasons, the main purpose of this article is firstly to establish that use of information technology is feasible in all industries, explain what possible obstacles for successful informatisation are, and which are major advantages after its implementation. Secondly, within theoretical aspect we present broaden view of informatisation in logistics, whilst practical example illustrates successful informatisation of transport process with adoption of GPS (Global Positioning System) in a transport firm. Furthermore, in this article we are also introducing a case study of three transport firms describing process flow before and after implementation identifying enhanced information quality, service quality and communication as a foremost advantages and achievements after informatisatio
Multistage Switching Architectures for Software Routers
Software routers based on personal computer (PC) architectures are becoming an important alternative to proprietary and expensive network devices. However, software routers suffer from many limitations of the PC architecture, including, among others, limited bus and central processing unit (CPU) bandwidth, high memory access latency, limited scalability in terms of number of network interface cards, and lack of resilience mechanisms. Multistage PC-based architectures can be an interesting alternative since they permit us to i) increase the performance of single software routers, ii) scale router size, iii) distribute packet manipulation and control functionality, iv) recover from single-component failures, and v) incrementally upgrade router performance. We propose a specific multistage architecture, exploiting PC-based routers as switching elements, to build a high-speed, largesize,scalable, and reliable software router. A small-scale prototype of the multistage router is currently up and running in our labs, and performance evaluation is under wa
Trade-throughs in European cross-traded equities after transaction costs – empirical evidence for the EURO STOXX 50
This paper investigates the accuracy and heterogeneity of output growth and inflation forecasts during the current and the four preceding NBER-dated U.S. recessions. We generate forecasts from six different models of the U.S. economy and compare them to professional forecasts from the Federal Reserve’s Greenbook and the Survey of Professional Forecasters (SPF). The model parameters and model forecasts are derived from historical data vintages so as to ensure comparability to historical forecasts by professionals. The mean model forecast comes surprisingly close to the mean SPF and Greenbook forecasts in terms of accuracy even though the models only make use of a small number of data series. Model forecasts compare particularly well to professional forecasts at a horizon of three to four quarters and during recoveries. The extent of forecast heterogeneity is similar for model and professional forecasts but varies substantially over time. Thus, forecast heterogeneity constitutes a potentially important source of economic fluctuations. While the particular reasons for diversity in professional forecasts are not observable, the diversity in model forecasts can be traced to different modeling assumptions, information sets and parameter estimates. JEL Classification: G14, G15, G2
Vehicular Networks with Infrastructure: Modeling, Simulation and Testbed
This thesis focuses on Vehicular Networks with Infrastructure. In the examined scenarios, vehicular nodes (e.g., cars, buses) can communicate with infrastructure roadside units (RSUs) providing continuous or intermittent coverage of an urban road topology. Different aspects related to the design of new applications for Vehicular Networks are investigated through modeling, simulation and testing on real field. In particular, the thesis: i) provides a feasible multi-hop routing solution for maintaining connectivity among RSUs, forming the wireless mesh infrastructure, and moving vehicles; ii) explains how to combine the UHF and the traditional 5-GHz bands to design and implement a new high-capacity high-efficiency Content Downloading using disjoint control and service channels; iii) studies new RSUs deployment strategies for Content Dissemination and Downloading in urban and suburban scenarios with different vehicles mobility models and traffic densities; iv) defines an optimization problem to minimize the average travel delay perceived by the drivers, spreading different traffic flows over the surface roads in a urban scenario; v) exploits the concept of Nash equilibrium in the game-theory approach to efficiently guide electric vehicles drivers' towards the charging stations. Moreover, the thesis emphasizes the importance of using realistic mobility models, as well as reasonable signal propagation models for vehicular networks. Simplistic assumptions drive to trivial mathematical analysis and shorter simulations, but they frequently produce misleading results. Thus, testing the proposed solutions in the real field and collecting measurements is a good way to double-check the correctness of our studie
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