2,204 research outputs found

    User’s Manual for Dynamic Programming for Highway Safety Improvement Program

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    The term, dynamic programming, was first used by Bellman to represent the mathematical theory of a multistage decision process. Dynamic programming is applied to allocate expenditures so that maximum benefits result. Three types of applications of dynamic programming are single-stage, multistage, and multistage with a time factor. Single-stage programming is used to evaluate a single project having several alternatives. Multistage programming involves selection of several projects having several alternatives. Multistage dynamic programming with a time factor is used where several projects and alternatives are considered and where various time periods are involved. The Alabama Highway Department did considerable work on the application of dynamic programming to the optimization of budget allocation for the spot-safety- improvement program. Significant modifications were incorporated into the Alabama procedures to make it applicable to the spot-safety-improvement program in Kentucky (3). That procedure was adapted to Kentucky\u27s needs and has been used periodically to select projects for the safety improvement program. Another application of dynamic programming in Kentucky has been for the selection of projects for resurfacing. With hundreds of candidate projects recommended for resurfacing each year, it is difficult to select projects that will yield the greatest benefits to the driving public. Prior to the application of dynamic programming to resurfacing projects, it was necessary to develop reliable means of calculating benefits derived from roadway resurfacing. Further use of the dynamic programming process in Kentucky has been for the development of a means to priority rank safety improvements for interstate and toll road facilities. Separate reports were prepared to document the procedures used for the interstate system and the toll road system. As was the case with other applications of dynamic programming, the major task was determination of benefits expected from each improvement. For both the interstate and toll road programs, all benefits were estimated to be the result of accident reductions associated with the improvements. The program described herein is designed specifically for highway projects. Program development was done in 1974 and several modifications have been made since then. Additional modifications were performed during the preparation of this user\u27s manual to make the program easier to use. A current listing of the program is in Appendix A

    A Supersymmetric Flipped SU(5) Intersecting Brane World

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    We construct an N=1 supersymmetric three-family flipped SU(5) model from type IIA orientifolds on T6/(Z2Ă—Z2)T^6/(\Z_2\times \Z_2) with D6-branes intersecting at general angles. The spectrum contains a complete grand unified and electroweak Higgs sector. In addition, it contains extra exotic matter both in bi-fundamental and vector-like representations as well as two copies of matter in the symmetric representation of SU(5).Comment: 17 pages, 3 tables, v2 published in Phys.Lett.

    Using assignment data to analyse a blended information literacy intervention: a quantitative approach

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    This research sought to determine whether a blended information literacy learning and teaching intervention could statistically significantly enhance undergraduates’ information discernment compared to standard face-to-face delivery. A mixture of face-to-face and online activities, including online social media learning, was used. Three interventions were designed to develop the information literacies of first-year undergraduates studying Sport and Exercise at Staffordshire University and focused on one aspect of information literacy: the ability to evaluate source material effectively. An analysis was devised where written evaluations of found information for an assessment were converted into numerical scores and then measured statistically. This helped to evaluate the efficacy of the interventions and provided data for further analysis. An insight into how the information literacy pedagogical intervention and the cognitive processes involved in enabling participants to interact critically with information is provided. The intervention which incorporated social media learning proved to be the most successful learning and teaching approach. The data indicated that undergraduate students’ information literacy can be developed. However, additional long-term data is required to establish whether this intervention would have a lasting impact

    The application of passive sampler (DGT) technology for improved understanding of metal behaviour at a marine disposal site

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    Metal behaviour and availability at a contaminated dredge material disposal site within UK waters has been investigated using Diffusive Gradient in Thin films (DGT) passive sampling technology. Three stations representing contrasting history and presence of maintenance dredge disposal, including a control station outside the disposal site, have been studied and depth profiles of fluxes of different metals (Fe, Mn, Pb, Cu, Cd, Cr, Ni, Zn) to the binding gel (Chelex 100) have been derived. Higher flux rates and shallower mobilisation of metals (Mn and Fe) to the binding gel were observed at the disposal stations compared to the control station. Here we describe metal mobilization at different depths, linking the remobilization of Fe2+ and Mn2+ to the sediment (re)supply of other heavy metals of interest with a focus on Cd, Ni and Pb and as they are on the Water Framework Directive (WFD) list of priority substances and OSPAR list of priority pollutants. Results showed that Cd, Pb and Ni exhibited signs of resupply at the sediment-water interface (SWI). There was a potential increased mobilisation and source to the water column of Pb and Ni at the disposal site stations, but there was no Cd source, despite higher total loadings. This information has the potential to improve our current understanding of metal cycles at disposal sites. This work can be used as an indication of likely metal bioavailability and also assist in determining whether the sites act as sources or sinks of heavy metals. This information could assist disposal site monitoring and dredge material licensing

    Concorde noise-induced building vibrations John F. Kennedy International Airport

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    The outdoor and indoor noise levels resulting from aircraft flyovers and certain nonaircraft events were recorded at six home sites along with the associated vibration levels in the walls, windows, and floors of these test homes. Limited subjective tests conducted to examine the human detection and annoyance thresholds for building vibration and rattle caused by aircraft noise showed that both vibration and rattle were detected subjectively in several houses for some operations of both the Concorde and subsonic aircraft. Preliminary results indicate that the relationship between window vibration and aircraft noise is: (1) linear, with vibration levels being accurately predicted from OASPL levels measured near the window; (2) consistent from flyover to flyover for a given aircraft type under approach conditions; (3) no different for Concorde than for other conventional jet transports (in the case of window vibrations induced under approach power conditions); and (4) relatively high levels of window vibration measured during Concorde operations are due more to higher OASPL levels than to unique Concorde source characteristics

    Multiple safety net regulators and agency problems in the EU : is Prompt Corrective Action partly the solution?

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    Incluye bibliografĂ­aThis paper presents a stylized mechanism aimed at dealing with the cross border agency problems that arise in supervising and resolving cross border banking groups in the European Union (EU). The authors assume that PCA policies have been implemented by the national supervisors and explore the institutional changes needed in Europe if PCA is to be effective as an incentive compatible mechanism. The paper identifies these changes starting with enhancements in the availability of information on banking groups to supervisors. Next, the paper considers the collective decision making by supervisors with authority to make discretionary decisions within the PCA framework as soon as a bank of a cross border banking group falls below the minimum capital standard. Finally, the paper analyzes the coordination measures that should be implemented if PCA requires the bank to be resolve

    Noise-Induced Building Vibrations Caused by Concorde and Conventional Aircraft Operations at Dulles and Kennedy International Airports

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    Outdoor and indoor noise levels resulting from aircraft flyovers and certain nonaircraft events were recorded, as were the associated vibration levels in the walls, windows, and floors at building test sites. In addition, limited subjective tests were conducted to examine the human detection and annoyance thresholds for building vibration and rattle caused by aircraft noise. Representative peak levels of aircraft noise-induced building vibrations are reported and comparisons are made with structural damage criteria and with vibration levels induced by common domestic events. In addition, results of a pilot study are reported which indicate the human detection threshold for noise-induced floor vibrations

    Concorde noise-induced building vibrations: John F. Kennedy International Airport

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    Outdoor and indoor noise levels resulting from aircraft flyovers and certain nonaircraft events were recorded at eight homesites and a school along with the associated vibration levels in the walls, windows, and floors at these test sites. Limited subjective tests were conducted to examine the human detection and annoyance thresholds for building vibration and rattle caused by aircraft noise. Both vibration and rattle were detected subjectively in several houses for some operations of both the Concorde and subsonic aircraft. Seated subjects more readily detected floor vibrations than wall or window vibrations. Aircraft noise generally caused more window vibrations than common nonaircraft events such as walking and closing doors. Nonaircraft events and aircraft flyovers resulted in comparable wall vibration levels, while floor vibrations were generally greater for nonaircraft events than for aircraft flyovers. The relationship between structural vibration and aircraft noise is linear, with vibration levels being accurately predicted from overall sound pressure levels (OASPL) measured near the structure. Relatively high levels of structural vibration measured during Concorde operations are due more to higher OASPL levels than to unique Concorde-source characteristics

    Concorde Noise-Induced Building Vibrations, Montgomery County, Maryland

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    A series of studies are reported to assess the noise induced building vibrations associated with Concorde operations. The levels of induced vibration and associated indoor/outdoor noise levels resulting from aircraft and nonaircraft events in selected homes, historic and other buildings near Dulles International Airport were recorded. The building response resulting from aircraft operations was found to be directly proportional to the overall sound pressure level and approximately independent of the aircraft type. The noise levels and, consequently, the response levels were observed to be higher for the Concorde operations than for the CTOL operations. Furthermore, the vibration could be closely reproduced by playing aircraft noise through a loudspeaker system located near the vibration measurement location. Nonaircraft events such as door closing were again observed to result in higher response levels than those induced by aircraft
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