1,142 research outputs found

    Urban Transport Pricing Reform With Two Levels Of Government

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    This paper analyses two challenges in the reform of urban transport pricing. The first challenge is the construction of an optimal package of urban transport pricing instruments assuming one benevolent government level that maximizes overall welfare. We examine the welfare gains from implementing in succession better parking prices, improved public transport prices and time varying tolling. It is found that parking and tolling are the most important elements of the optimal package and that the alternative policy instruments are sub-additive in their benefits. The second problem studied is the use of these pricing instruments by different government levels. We examine a case where an urban government controls parking fees and the regional government controls the tolling. Although both government levels have different objective functions, we find that the overall efficiency losses in the Nash and Stackelberg equilibria are limited.

    PsrPopPy: An open-source package for pulsar population simulations

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    We have produced a new software package for the simulation of pulsar populations, \textsc{PsrPopPy}, based on the \textsc{Psrpop} package. The codebase has been re-written in Python (save for some external libraries, which remain in their native Fortran), utilising the object-oriented features of the language, and improving the modularity of the code. Pre-written scripts are provided for running the simulations in `standard' modes of operation, but the code is flexible enough to support the writing of personalised scripts. The modular structure also makes the addition of experimental features (such as new models for period or luminosity distributions) more straightforward than with the previous code. We also discuss potential additions to the modelling capabilities of the software. Finally, we demonstrate some potential applications of the code; first, using results of surveys at different observing frequencies, we find pulsar spectral indices are best fit by a normal distribution with mean −1.4-1.4 and standard deviation 1.01.0. Second, we model pulsar spin evolution to calculate the best-fit for a relationship between a pulsar's luminosity and spin parameters. We used the code to replicate the analysis of Faucher-Gigu\`ere & Kaspi, and have subsequently optimized their power-law dependence of radio luminosity, LL, with period, PP, and period derivative, P˙\dot{P}. We find that the underlying population is best described by L∝P−1.39±0.09P˙0.48±0.04L \propto P^{-1.39 \pm 0.09} \dot{P}^{0.48 \pm 0.04} and is very similar to that found for Îł\gamma-ray pulsars by Perera et al. Using this relationship, we generate a model population and examine the age-luminosity relation for the entire pulsar population, which may be measurable after future large-scale surveys with the Square Kilometer Array.Comment: 11 pages, 7 figure

    Developing a Customer Feedback Instrument to Improve Quality and Increase Usage of Special Education Goal Measurement Software

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    A software programmer at the Southeast Kansas Education Service Center has developed the Skill Demonstration (SD) software for the Special Education classroom. SD has been used by 25 school districts for the past three years. A recent analysis of ‘last user login dates’ was performed revealing a great decline in usage. The goal of this field project was to create an instrument to communicate with SD users to determine reasons for usage decline. The instrument contained 14 questions, which were selected based on SD user interviews and literature research performed about customer/user information satisfaction. The instrument received 21.5% response rate. More than 89% of respondents supported SD being user friendly, conveniently available, providing sufficient information to make useful decisions, displaying clear formatted graphs, tables and data accuracy, keeping data confidentiality, and users were willing to recommend SD to colleagues. The instrument responses also suggested that SD was marketed online very poorly with 2.6% of participants discovering SD online. Forty-one percent of participants initiated communication regarding SD questions, leaving room for encouraging more communication with SD staff. The in-person training was believed to be effective by 79.5% of participants, which can be improved. The participants’ comments provided reasons for SD’s usage decline. SD is currently lacking user-desired features such as additional graphing features, data collection methods and having a bank of pre-entered skills. The conclusion of the project was the programmer would have to meet participants in-person to discuss adding desired features. A recommendation for additional work was for the programmer to encourage users to participate in the instrument again next year and compare next year’s results with the current results

    Immunogenomics of the Rhesus macaque, an animal model for HIV vaccine development

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    Human Immunodeficiency Virus (HIV) is a lentivirus that causes Acquired Immunodeficiency Syndrome (AIDS) resulting in the progressive failure of the immune system. Due to its rapid replication rate and high mutation frequency, the virus is able to evade the immune system and thwart an efficacious response. Current HIV infection prophylaxes and therapeutics are not optimal and there is an urgent need to develop an efficacious HIV vaccine. Recently, high-throughput sequencing of the Immunoglobulin (Ig) repertoire from HIV-infected humans and immunized Rhesus macaques has led to important insights into vaccines against HIV-1. Further elucidation of the antibody response in these crucial animal studies will require substantially greater power to analyze the Ig repertoires than is currently possible. Reliable information on macaque Ig genes is insufficient due to the incompleteness of the whole genome sequence (WGS) and the inherent difficulty of obtaining complete Ig sequences due to its complex and repetitive nature. To address this issue, we have generated a high quality, annotated WGS with precisely annotated Ig loci from ten macaques. We used low error, synthetic long reads generated by Illumina TruSeq technology, Illumina 150bp, paired-end reads (110X coverage) and Irys genome mapping technology to assemble the genome de novo. We employed a bait-and-sequence strategy using human Ig probes to capture macaque Ig genes for the accurate assembly and annotation of Ig genes and alleles. Together, these data will generate a complete Rhesus macaque genome with detailed information on allelic diversity at the Ig loci. This study is essential for making the macaque a viable model for adaptive immunity. In addition, it will provide information on the similarities and differences between macaque and human Ig genes that will aid in the design and interpretation of vaccine studies

    Lower Bounds for Shoreline Searching With 2 or More Robots

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    Searching for a line on the plane with nn unit speed robots is a classic online problem that dates back to the 50's, and for which competitive ratio upper bounds are known for every n≄1n\geq 1. In this work we improve the best lower bound known for n=2n=2 robots from 1.5993 to 3. Moreover we prove that the competitive ratio is at least 3\sqrt{3} for n=3n=3 robots, and at least 1/cos⁥(π/n)1/\cos(\pi/n) for n≄4n\geq 4 robots. Our lower bounds match the best upper bounds known for n≄4n\geq 4, hence resolving these cases. To the best of our knowledge, these are the first lower bounds proven for the cases n≄3n\geq 3 of this several decades old problem.Comment: This is an updated version of the paper with the same title which will appear in the proceedings of the 23rd International Conference on Principles of Distributed Systems (OPODIS 2019) Neuchatel, Switzerland, July 17-19, 201
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