16,414 research outputs found

    The Economics of Multi-Hop Ride Sharing - Creating New Mobility Networks Through IS

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    Ride sharing allows to share costs of traveling by car, e.g., for fuel or highway tolls. Furthermore, it reduces congestion and emissions by making better use of vehicle capacities. Ride sharing is hence beneficial for drivers, riders, as well as society. While the concept has existed for decades, ubiquity of digital and mobile technology and user habituation to peer-to-peer services and electronic markets have resulted in particular growth in recent years. This paper explores the novel idea of multi-hop ride sharing and illustrates how information systems can leverage its potential. Based on empirical ride sharing data, we provide a quantitative analysis of the structure and the economics of electronic ride sharing markets. We explore the potential and competitiveness of multi-hop ride sharing and analyze its implications for platform operators. We find that multi-hop ride sharing proves competitive against other modes of transportation and has the potential to greatly increase ride availability and city connectedness, especially under high reliability requirements. To fully realize this potential, platform operators should implement multi-hop search, assume active control of pricing and booking processes, improve coordination of transfers, enhance data services, and try to expand their market share

    An Analysis of issues against the adoption of Dynamic Carpooling

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    Using a private car is a transportation system very common in industrialized countries. However, it causes different problems such as overuse of oil, traffic jams causing earth pollution, health problems and an inefficient use of personal time. One possible solution to these problems is carpooling, i.e. sharing a trip on a private car of a driver with one or more passengers. Carpooling would reduce the number of cars on streets hence providing worldwide environmental, economical and social benefits. The matching of drivers and passengers can be facilitated by information and communication technologies. Typically, a driver inserts on a web-site the availability of empty seats on his/her car for a planned trip and potential passengers can search for trips and contact the drivers. This process is slow and can be appropriate for long trips planned days in advance. We call this static carpooling and we note it is not used frequently by people even if there are already many web-sites offering this service and in fact the only real open challenge is widespread adoption. Dynamic carpooling, on the other hand, takes advantage of the recent and increasing adoption of Internet-connected geo-aware mobile devices for enabling impromptu trip opportunities. Passengers request trips directly on the street and can find a suitable ride in just few minutes. Currently there are no dynamic carpooling systems widely used. Every attempt to create and organize such systems failed. This paper reviews the state of the art of dynamic carpooling. It identifies the most important issues against the adoption of dynamic carpooling systems and the proposed solutions for such issues. It proposes a first input on solving the problem of mass-adopting dynamic carpooling systems.Comment: 10 pages, whitepaper, extracted from B.Sc. thesis "Dycapo: On the creation of an open-source Server and a Protocol for Dynamic Carpooling" (Daniel Graziotin, 2010

    ATP: a Datacenter Approximate Transmission Protocol

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    Many datacenter applications such as machine learning and streaming systems do not need the complete set of data to perform their computation. Current approximate applications in datacenters run on a reliable network layer like TCP. To improve performance, they either let sender select a subset of data and transmit them to the receiver or transmit all the data and let receiver drop some of them. These approaches are network oblivious and unnecessarily transmit more data, affecting both application runtime and network bandwidth usage. On the other hand, running approximate application on a lossy network with UDP cannot guarantee the accuracy of application computation. We propose to run approximate applications on a lossy network and to allow packet loss in a controlled manner. Specifically, we designed a new network protocol called Approximate Transmission Protocol, or ATP, for datacenter approximate applications. ATP opportunistically exploits available network bandwidth as much as possible, while performing a loss-based rate control algorithm to avoid bandwidth waste and re-transmission. It also ensures bandwidth fair sharing across flows and improves accurate applications' performance by leaving more switch buffer space to accurate flows. We evaluated ATP with both simulation and real implementation using two macro-benchmarks and two real applications, Apache Kafka and Flink. Our evaluation results show that ATP reduces application runtime by 13.9% to 74.6% compared to a TCP-based solution that drops packets at sender, and it improves accuracy by up to 94.0% compared to UDP

    Suspension Testing of 3 Heavy Vehicles - Methodology and Preliminary Frequency Analysis

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    Three air-sprung heavy vehicles (HVs) were instrumented and tested on typical suburban and highway road sections at typical operational speeds. The vehicles used were a tri-axle semi-trailer towed with a prime mover, an interstate coach with 3 axles and a school bus with 2 axles. The air springs (air bags) of the axle/axle group of interest were configured such that they could be connected using either standard longitudinal air lines or an innovative suspension system comprising larger-than-standard longitudinal air lines. Data for dynamic forces on axles, wheels and chassis were gathered for the purposes of: analysis of the relative performance of the HVs for the two sizes of air lines; informing the QUT/Main Roads project Heavy vehicle suspensions – testing and analysis; and providing a reference source for future projects. This reports sets down the methodology and preliminary results of the testing carried out. Accordingly, Fast-Fourier plots are provided to show indicative frequency spectra for HV axles, wheel forces and air springs during typical use. The results are documented in Appendices 3 to 5. There appears to be little or no correlation between dynamic forces in the air springs and the wheel forces in the HVs tested. Axle-hop at frequencies between 10-15 Hz predominated for unsprung masses in the HV suspensions tested. Air-spring forces are present in the sub-1.0 Hz to approximately 2 Hz frequency range. With the qualification that only one set of data from each test speed is presented herein, in general, the peaks in the frequency spectra of the body-bounce forces and wheel forces were reduced for the tests with the larger longitudinal air lines. More research needs to be done on the load sharing mechanisms between axles on air-sprung HVs. In particular, how and whether improved load sharing can be effected and whether better load sharing between axles will reduce dynamic wheel and chassis forces. This last point, in particular, in relation to the varied dynamic measures used by the HV testing community to compare different suspension types

    Spartan Daily, September 25, 2003

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    Volume 121, Issue 20https://scholarworks.sjsu.edu/spartandaily/9886/thumbnail.jp
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