15,208 research outputs found
The DSR-deformed relativistic symmetries and the relative locality of 3D quantum gravity
Over the last decade there were significant advances in the understanding of
quantum gravity coupled to point particles in 3D (2+1-dimensional) spacetime.
Most notably it is emerging that the theory can be effectively described as a
theory of free particles on a momentum space with anti-deSitter geometry and
with noncommutative spacetime coordinates of the type . We here show
that the recently proposed relative-locality curved-momentum-space framework is
ideally suited for accommodating these structures characteristic of 3D quantum
gravity. Through this we obtain an intuitive characterization of the
DSR-deformed Poincar\'e symmetries of 3D quantum gravity, and find that the
associated relative spacetime locality is of the type producing dual-gravity
lensing.Comment: LaTex, 12 pages, 3 figure
Scalable Layer-2/Layer-3 Multistage Switching Architectures for Software Routers
Software routers are becoming an important alternative to proprietary and expensive network devices, because they exploit the economy of scale of the PC market and open-source software. When considering maximum performance in terms of throughput, PC-based routers suffer from limitations stemming from the single PC architecture, e.g., limited bus bandwidth, and high memory access latency. To overcome these limitations, in this paper we present a multistage architecture that combines a layer-2 load-balancer front-end and a layer-3 routing back-end, interconnected by standard Ethernet switches. Both the front-end and the back-end are implemented using standard PCs and open- source software. After describing the architecture, evaluation is performed on a lab test-bed, to show its scalability. While the proposed solution allows to increase performance of PC- based routers, it also allows to distribute packet manipulation functionalities, and to automatically recover from component failures
Effective Transportation Demand Management: The Results of Combining Parking Pricing, Transit Incentives, and Transportation Management in a Commercial District of Portland, Oregon
The Lloyd District is a high-density commercial and residential district located a short distance from downtown Portland, Oregon. Parking and transportation problems in the District have been a source of increasing contention for nearly a decade. As a result. in September of 1997. the City of Portland implemented a Lloyd District Partnership Plan, which consists of a number of elements aimed at curbing SOY use for the commute to and from the District. This plan included parking pricing in the form of meters, w\u27here on-street parking had previously been free: discounted transit passes: and other transportation demand management (TOM) strategies.
This research assesses the effects of these strategics on travel and parking behavior, with an emphasis on the relationship between parking pricing and mode choice. A random sample of I 000 employees in the Lloyd District was surveyed about their travel and parking behavior before and after the installation of the new meters.
This research finds that during the one year that had elapsed between the implementation of the Lloyd District transportation management programs and the survey information collected by this study, the drive-alone mode for the trip to work by employees in the Lloyd District had decreased by 7 percent. For the District as a whole. the drive-alone commute share is now about 56 percent. The program·s strategies that have emerged as the most significant in effecting this decrease arc the installation of the meters and the discounted transit pass program
Evaluation of the Lloyd District Parking Programs, City of Portland: The Impacts of Parking Pricing and Transportation Management Association Programs in a High-Density, Mixed-Use District
This is the final report of the Lloyd District transportation management program and the subsequent survey.
During the one year that had elapsed between the implementation of the Lloyd District transportation and management programs and the survey information collected in this study, the drive alone mode for the trip to work by employees in the Lloyd District had decreased by 7 percent. For the District as a whole, the drive alone commute share is about 56 percent. These are remarkable achievements
Kennedy, 60 Minutes, and Roger Rabbit: Understanding Conspiracy-Theory Explanations of The Decline of Urban Mass Transit
This paper will review the history of the GM Conspiracy Myth, as well as what legal theorists refer to as the facts in the case. The legal explanation of what really happened goes only so far, though. The whole story about the decline of mass transit in the U.S. is a story about the failure of public policy and about conflict among competing constituencies in the transportation policy process. This paper will very briefly discuss this failure and this conflict and will then conclude with a consideration of - or at least a hypothesis for - the endurance of the GM Conspiracy Myth
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