172 research outputs found
Transportation investments in the Philadelphia metropolitan area: who benefits? Who pays? And what are the consequences?
No full textIn this paper, the author examines the geographic distribution of transportation investments as well as the question of who pays for the investments in the Philadelphia metropolitan area, focusing on differences between the city and its surrounding Pennsylvania suburban counties. The author presents estimates of total, per capita, and per user benefits of highway investments, as well as fees generated by highway users at the county level. The author also examines the combined highway and transit investments in the suburbs as a whole and in the city. ; There are three central findings in this analysis: (1) Highway capital expenditures in the Greater Philadelphia region are significantly higher on a per capita basis in the Pennsylvania suburbs than in the city of Philadelphia. Over the 10 years from 1986-1995, expenditures benefiting suburban residents are estimated to be 424 per capita. (2) Total highway user fees generated differ significantly across communities because of different auto ownership rates. Users fees do not, however, have differential effects on the attractiveness of communities because the user fees that individual drivers pay are the same across communities. (3) The per user differences between Philadelphia and its suburbs are smaller than per capita differences. Per user differences affect the degree to which car travel is favored in the city versus the suburbs, but it does not capture the location effects of investment in transportation infrastructure. ; The difference in per capita expenditures is likely to have a significant effect on the competitive position of the city of Philadelphia relative to its suburbs. Highway investments have provided an economically significant, although not overwhelming, incentive for suburban rather than city locations for people and firms. The author estimates that the highway investment differential reduces employment in the city by about 40,000 jobs.Local transit ; Philadelphia (Pa.)
A Real-time Service Oriented Infrastructure
No full textThe advancements in distributed computing have driven the emergence of service-based infrastructures that allow for on-demand provision of ICT assets. Taking into consideration the complexity of distributed environments, significant challenges exist in providing and managing the offered on-demand resources with the required level of Quality of Service (QoS), especially for real-time interactive and streaming applications. In this paper we propose an approach for providing real-time QoS guarantees by enhancing service oriented infrastructures with coherent and consistent real-time attributes at various levels (application, network, storage, processing). The approach considers the full lifecycle of service-based systems including service engineering, Service Level Agreement (SLA) negotiation and management, service provisioning and monitoring. QoS parameters at application, platform and infrastructure levels are given specific attention as the basis for provisioning policies in the context of temporal constraint
Virtualised e-Learning with Real-Time Guarantees on the IRMOS Platform1
No full textIn this paper we focus on how Quality of Service guarantees are provided to virtualised applications in the Cloud Computing infrastructure that is being developed in the context of the IRMOS1 European Project. Provisioning of proper timeliness guarantees to distributed real-time applications involves the careful use of real-time scheduling mechanisms at the virtual-machine hypervisor level, of QoS-aware networking protocols and of proper design methodologies and tools for stochastic modelling of the application. The paper focuses on how we applied these techniques to a case-study involving a real e- Learning mobile content delivery application that has been integrated into the IRMOS platform and its achieved performanc
Execution and Resource Management in QoS-Aware Virtualized Infrastructures
No full textBoth real-time systems and virtualization have been important research topics for quite some time now. Having competing goals, research on the correlation of these topics has started only recently. This chapter overviews recent results in the research literature on virtualized large-scale systems and soft real-time systems. These concepts constitute the fundamental background over which the execution environment of any large-scale service-oriented real-time architecture for highly interactive, distributed, and virtualized applications will be built in the future. While many aspects covered in this chapter have already been adopted in commercial products, others are still under intensive investigation in research labs all over the world
Monitoring and metering on the cloud
No full textReal-time systems are of importance to a large number of university laboratories and research institutes worldwide, and without the proper integration of real-time into distributed computing, institutions simply could not function. Achieving Real-Time in Distributed Computing: From Grids to Clouds offers over 400 accounts from a wide range of specific research efforts. Major focus is given to the need for methodologies, tools, and architectures for complex distributed systems that address the practical issues of performance guarantees, timed execution, real-time management of resources, synchronized communication under various load conditions, satisfaction of QoS constraints, and dealing with the trade-offs between these aspect
Cavitation in a bulb turbine
No full textThe flow in a horizontal shaft bulb turbine is calculated as a two-phase flow with a commercial Computational Fluid Dynamics (CFD-)-code including cavitation model. The results are compared with experimental results achieved at a closed loop test rig for model turbines. On the model test rig, for a certain operating point (i.e.volume flow, net head, blade angle, guide vane opening) the pressure behind the turbine is lowered (i.e. the Thomacoefficient s is lowered) and the efficiency of the turbine is recorded. The measured values can be depicted in a so-called s?break curve or h-s?diagram. Usually, the efficiency is independent of the Thoma-coefficient up to a certain value. When lowering the Thoma-coefficient below this value the efficiency will drop rapidly. Visual observations of the different cavitation conditions complete the experiment. In analogy, several calculations are done for different Thoma-coefficients s and the corresponding hydraulic losses of the runner are evaluated quantitatively. Besides, the fraction of water vapour as an indication of the size of the cavitation cavity is analyzed qualitatively. The experimentally and the numerically obtained results are compared and show a good agreement. Especially the drop in efficiency can be calculated with satisfying accuracy. This drop in efficiency is of high practical importance since it is one criterion to determine the admissible cavitation in a bulbturbine. The visual impression of the cavitation in the CFDanalysis is well in accordance with the observed cavitation bubbles recorded on sketches and/or photographs.http://deepblue.lib.umich.edu/bitstream/2027.42/84277/1/CAV2009-final91.pd
Virtualised e-Learning on the IRMOS real-time cloud
No full textProviding proper timeliness guarantees to distributed soft real-time applications in a virtualised infrastructure involves the careful use of various techniques at different levels, ranging from real-time scheduling mechanisms at the virtual-machine hypervisor level and QoS-aware protocols at the network level, to proper design methodologies and tools for stochastic modelling and runtime provisioning of the applications. This paper describes the way these techniques were combined to provide strong quality of service guarantees to interactive soft real-time applications in the Cloud Computing infrastructure that has been developed in the context of the IRMOS European Project. The efficiency of the developed infrastructure is demonstrated by two real interactive e-Learning applications, an e-Learning mobile content delivery application and a virtual world e-Learning application, both of which have been integrated into the IRMOS platfor
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Session B2: An Overview of the Ice Harbor Turbine Replacement Project
No full textPresenting Author Bio:
Mr. Ahmann is a Senior Hydraulic Engineer for the US Army Corps of Engineers’ Walla-Walla District. He is a registered professional engineer and has been involved with the hydraulic design of fish passage improvements at the USACE hydropower projects for 18 years. Martin is the senior technical lead for the USACE Turbine Survival Program, which was established to improve turbine operations and design for safer fish passage throughout the Federal Columbia River Hydropower System (FCRPS). He is also the Walla Walla District’s lead hydraulic engineer for the Ice Harbor turbine design and replacement project.Abstract: In March of 2010 the US Army Corps of Engineers’ (USACE) awarded a contract to Voith Hydro to design and supply new turbine runners for installation at the Ice Harbor Lock and Dam located on the Lower Snake River within the State of Washington, USA. The contract included design and supply of both a fixed and an adjustable blade turbine runner for replacement of two failing units within the six unit powerhouse. The new turbine runners were to be designed for “safer” fish passage as a primary goal, and increased efficiency as a secondary goal. The hydraulic design of both runner types was a collaborative effort by the USACE’s Walla Walla District (NWW), Engineer Research and Development Center (ERDC), Hydroelectric Design Center (HDC), National Marine Fisheries Service (NMFS) and Voith Hydro. The design criteria and the design evaluation process were developed by the USACE over years of both field and laboratory research through the Turbine Survival Program. The two runner types were designed through an iterative process of Computational Fluid Dynamic Model analysis, performance model testing for power, efficiency and cavitation, and physical hydraulic model testing for evaluation of the turbine passage environment. This presentation provides a broad overview of the research, design criteria and guidelines, the design and evaluation process, and future biological field testing efforts supporting the Ice Harbor turbine runner replacement project
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Session B3: Replacement Turbine Design for Improved Fish Passage at Ice Harbor
No full textPresenting Author Bio: Dr. Jason Foust is employed by Voith Hydro, Inc. in York, Pennsylvania. After completing his graduate studies in Experimental Fluid mechanics, he began working as a hydraulic engineer. Since that time, Dr. Foust has focused on design and testing for turbine rehabilitation projects. In addition to his design responsibilities, he has also been involved in the development of environmentally friendly hydro turbines in regard to turbine aeration and fish passage.Abstract: In the summer of 2014, an extensive hydraulic development was completed for replacement fixed and adjustable blade turbines for the US Army Corps of Engineers’ (USACE) Ice Harbor Lock and Dam. During the hydraulic design phase, fish passage considerations made up the primary evaluation criteria, including minimum pressures, shear, flow quality, and blade strike. Expected fish passage characteristics for each set of proposed geometries were evaluated using both Computational Fluid Dynamic (CFD) calculations and physical model testing. Turbine performance characteristics, such as power and efficiency, were also considered as secondary evaluation criteria. For both machine types, several design and test loops were completed. At the end of each iteration, the design team, consisting of engineers and biologists from the USACE, Voith Hydro, and the National Marine Fisheries Service (NMFS), evaluated the results and identified aspects of the fish passage environment that could be improved. As the design process neared completion, final improvements to the overall fish passage environment involved making compromises between the individual design criteria. The current paper presents computational and model test results to illustrate the detailed design and evaluation process, including the trade-offs that were made leading up to the selection of the final prototype fixed blade turbine geometry. Comparison of the fish passage evaluations for the fixed blade solution with those of the existing Ice Harbor Kaplan geometry shows significant potential for fish passage improvement
Closed-loop velocity control for an AGV equipped with a modified Voith-Schneider-Drive
No full textS.10.1-10.14Today state-of-the-art movement of automated guided vehicles is mostly unidirectional which needs more space in curves and decreases the flexibility and mutability of such systems in warehouse or facilities. With this focus a new omnidirectional drive concept for Automated Guided Vehicles (AGV) was developed at the Fraunhofer IML. The concept of the Voith-Schneider ship drive is the control of the velocity and the position of an AGV. Mechanical parameters have a major impact on the directional stability. Because of these reasons a close loop control is a strong condition for precise velocity and position control. The rotional and translational velocity closed-loop control is exemplarily realized by 6 degrees of freedom MEMS IMU. Further focus of research was the optimization of maneuverability and energy consumption
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