7,981 research outputs found

    Defining and Measuring The Creation of Quality Jobs

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    Our research is intended to support our peers in the Community Development Financial Institution (CDFI) industry who, through their financing, have served low-income and other disadvantaged communities for two decades.  While the CDFI industry has been instrumental in supporting job creation across the U.S., we believe that now is the time to focus greater attention on the quality of the jobs created in order to combat rising income and wealth inequality.Through a better understanding of what defines a quality job and a set of practical methods for measuring the quality of jobs created, we believe CDFIs and others in the impact investing community will be better positioned to make more effective investments that support good jobs for workers, businesses, and communities

    GPU Based Path Integral Control with Learned Dynamics

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    We present an algorithm which combines recent advances in model based path integral control with machine learning approaches to learning forward dynamics models. We take advantage of the parallel computing power of a GPU to quickly take a massive number of samples from a learned probabilistic dynamics model, which we use to approximate the path integral form of the optimal control. The resulting algorithm runs in a receding-horizon fashion in realtime, and is subject to no restrictive assumptions about costs, constraints, or dynamics. A simple change to the path integral control formulation allows the algorithm to take model uncertainty into account during planning, and we demonstrate its performance on a quadrotor navigation task. In addition to this novel adaptation of path integral control, this is the first time that a receding-horizon implementation of iterative path integral control has been run on a real system.Comment: 6 pages, NIPS 2014 - Autonomously Learning Robots Worksho

    Chaining Test Cases for Reactive System Testing (extended version)

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    Testing of synchronous reactive systems is challenging because long input sequences are often needed to drive them into a state at which a desired feature can be tested. This is particularly problematic in on-target testing, where a system is tested in its real-life application environment and the time required for resetting is high. This paper presents an approach to discovering a test case chain---a single software execution that covers a group of test goals and minimises overall test execution time. Our technique targets the scenario in which test goals for the requirements are given as safety properties. We give conditions for the existence and minimality of a single test case chain and minimise the number of test chains if a single test chain is infeasible. We report experimental results with a prototype tool for C code generated from Simulink models and compare it to state-of-the-art test suite generators.Comment: extended version of paper published at ICTSS'1

    Development and Application of a Statistically-Based Quality Control for Crowdsourced Air Temperature Data

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    In urban areas, dense atmospheric observational networks with high-quality data are still a challenge due to high costs for installation and maintenance over time. Citizen weather stations (CWS) could be one answer to that issue. Since more and more owners of CWS share their measurement data publicly, crowdsourcing, i.e., the automated collection of large amounts of data from an undefined crowd of citizens, opens new pathways for atmospheric research. However, the most critical issue is found to be the quality of data from such networks. In this study, a statistically-based quality control (QC) is developed to identify suspicious air temperature (T) measurements from crowdsourced data sets. The newly developed QC exploits the combined knowledge of the dense network of CWS to statistically identify implausible measurements, independent of external reference data. The evaluation of the QC is performed using data from Netatmo CWS in Toulouse, France, and Berlin, Germany, over a 1-year period (July 2016 to June 2017), comparing the quality-controlled data with data from two networks of reference stations. The new QC efficiently identifies erroneous data due to solar exposition and siting issues, which are common error sources of CWS. Estimation of T is improved when averaging data from a group of stations within a restricted area rather than relying on data of individual CWS. However, a positive deviation in CWS data compared to reference data is identified, particularly for daily minimum T. To illustrate the transferability of the newly developed QC and the applicability of CWS data, a mapping of T is performed over the city of Paris, France, where spatial density of CWS is especially high.DFG, 322579844, Hitzewellen in Berlin, Deutschland - StadtklimamodifkationenBMBF, 01LP1602A, Verbundprojekt Stadtklima: Evaluierung von Stadtklimamodellen (Modul B), 3DO Teilprojekt 1: Dreidimensionales Monitoring atmosphärischer Prozesse in Berli

    A Variable PV Broad Absorption Line and Quasar Outflow Energetics

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    Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that might exist in all quasars and could play a major role in feedback to galaxy evolution. The viability of BAL outflows as a feedback mechanism depends on their kinetic energies, as derived from the outflow velocities, column densities, and distances from the central quasar. We estimate these quantities for the quasar, Q1413+1143 (redshift ze=2.56z_e = 2.56), aided by the first detection of PV λλ\lambda\lambda1118,1128 BAL variability in a quasar. In particular, PV absorption at velocities where the CIV trough does not reach zero intensity implies that the CIV BAL is saturated and the absorber only partially covers the background continuum source (with characteristic size <0.01 pc). With the assumption of solar abundances, we estimate that the total column density in the BAL outflow is log N_H > 22.3 (cm^-2). Variability in the PV and saturated CIV BALs strongly disfavors changes in the ionization as the cause of the BAL variability, but supports models with high-column density BAL clouds moving across our lines of sight. The observed variability time of 1.6 yr in the quasar rest frame indicates crossing speeds >750 km/s and a radial distance from the central black hole of <3.5 pc, if the crossing speeds are Keplerian. The total outflow mass is ~4100 M_solar, the kinetic energy ~4x10^54 erg, and the ratio of the outflow kinetic energy luminosity to the quasar bolometric luminosity is ~0.02 (at the minimum column density and maximum distance), which might be sufficient for important feedback to the quasar's host galaxy.Comment: 9 pages, 4 figures, accepted for publication in MNRA

    Relationship between size, effort, duration and number of contributors in large FLOSS projects

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    This contribution presents initial results in the study of the relationship between size, effort, duration and number of contributors in eleven evolving Free/Libre Open Source Software (FLOSS) projects, in the range from approx. 650,000 to 5,300,000 lines of code. Our initial motivation was to estimate how much effort is involved in achieving a large FLOSS system. Software cost estimation for proprietary projects has been an active area of study for many years. However, to our knowledge, no previous similar research has been conducted in FLOSS effort estimation. This research can help planning the evolution of future FLOSS projects and in comparing them with proprietary systems. Companies that are actively developing FLOSS may benefit from such estimates. Such estimates may also help to identify the productivity ’baseline’ for evaluating improvements in process, methods and tools for FLOSS evolution
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