5,619 research outputs found

    Towards a Smart World: Hazard Levels for Monitoring of Autonomous Vehicles’ Swarms

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    This work explores the creation of quantifiable indices to monitor the safe operations and movement of families of autonomous vehicles (AV) in restricted highway-like environments. Specifically, this work will explore the creation of ad-hoc rules for monitoring lateral and longitudinal movement of multiple AVs based on behavior that mimics swarm and flock movement (or particle swarm motion). This exploratory work is sponsored by the Emerging Leader Seed grant program of the Mineta Transportation Institute and aims at investigating feasibility of adaptation of particle swarm motion to control families of autonomous vehicles. Specifically, it explores how particle swarm approaches can be augmented by setting safety thresholds and fail-safe mechanisms to avoid collisions in off-nominal situations. This concept leverages the integration of the notion of hazard and danger levels (i.e., measures of the “closeness” to a given accident scenario, typically used in robotics) with the concept of safety distance and separation/collision avoidance for ground vehicles. A draft of implementation of four hazard level functions indicates that safety thresholds can be set up to autonomously trigger lateral and longitudinal motion control based on three main rules respectively based on speed, heading, and braking distance to steer the vehicle and maintain separation/avoid collisions in families of autonomous vehicles. The concepts here presented can be used to set up a high-level framework for developing artificial intelligence algorithms that can serve as back-up to standard machine learning approaches for control and steering of autonomous vehicles. Although there are no constraints on the concept’s implementation, it is expected that this work would be most relevant for highly-automated Level 4 and Level 5 vehicles, capable of communicating with each other and in the presence of a monitoring ground control center for the operations of the swarm

    Fast method for the determination of short-chain-length polyhydroxyalkanoates (scl-PHAs) in bacterial samples by In Vial-Thermolysis (IVT)

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    none8siA new method based on the GC–MS analysis of thermolysis products obtained by treating bacterial samples at a high temperature (above 270 C) has been developed. This method, here named “In-Vial- Thermolysis” (IVT), allowed for the simultaneous determination of short-chain-length polyhydrox- yalkanoates (scl-PHA) content and composition. The method was applied to both single strains and microbial mixed cultures (MMC) fed with different carbon sources. The IVT procedure provided similar analytical performances compared to previous Py-GC–MS and Py- GC-FID methods, suggesting a similar application for PHA quantitation in bacterial cells. Results from the IVT procedure and the traditional methanolysis method were compared; the correlation between the two datasets was fit for the purpose, giving a R2 of 0.975. In search of further simplification, the rationale of IVT was exploited for the development of a “field method” based on the titration of thermolyzed samples with sodium hydrogen carbonate to quantify PHA inside bacterial cells. The accuracy of the IVT method was fit for the purpose. These results lead to the possibility for the on-line measurement of PHA productivity. Moreover, they allow for the fast and inexpensive quantification/characterization of PHA for biotechnological process control, as well as investigation over various bacterial communities and/or feeding strategies.mixedF. Abbondanzi; G. Biscaro; G. Carvalho; L. Favaro; P. Lemos; M. Paglione; C. Samorì; C. TorriF. Abbondanzi; G. Biscaro; G. Carvalho; L. Favaro; P. Lemos; M. Paglione; C. Samorì; C. Torr

    Influência da secagem da polpa na composição centesimal de tortas de macaúba do Pantanal de Mato Grosso do Sul.

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    Objetivou-se, neste trabalho, avaliar os efeitos de diferentes processos de secagem dos frutos na composição centesimal de torta da polpa da macaúba proveniente da região do Pantanal de Corumbá, Mato Grosso do Sul

    Analysis of Disengagements in Semi-Autonomous Vehicles: Drivers’ Takeover Performance and Operational Implications

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    This report analyzes the reactions of human drivers placed in simulated Autonomous Technology disengagement scenarios. The study was executed in a human-in-the-loop setting, within a high-fidelity integrated car simulator capable of handling both manual and autonomous driving. A population of 40 individuals was tested, with metrics for control takeover quantification given by: i) response times (considering inputs of steering, throttle, and braking); ii) vehicle drift from the lane centerline after takeover as well as overall (integral) drift over an S-turn curve compared to a baseline obtained in manual driving; and iii) accuracy metrics to quantify human factors associated with the simulation experiment. Independent variables considered for the study were the age of the driver, the speed at the time of disengagement, and the time at which the disengagement occurred (i.e., how long automation was engaged for). The study shows that changes in the vehicle speed significantly affect all the variables investigated, pointing to the importance of setting up thresholds for maximum operational speed of vehicles driven in autonomous mode when the human driver serves as back-up. The results shows that the establishment of an operational threshold could reduce the maximum drift and lead to better control during takeover, perhaps warranting a lower speed limit than conventional vehicles. With regards to the age variable, neither the response times analysis nor the drift analysis provide support for any claim to limit the age of drivers of semi-autonomous vehicles

    Crioarenado: una nueva opción para la limpieza de edificios patrimoniales

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    Uno de los requerimientos más importantes para una intervención de limpieza de las superficies en un edificio histórico es que deben ser eliminados los materiales depositados sin modificar las superficies originales, y por último no es menos importante, asegurar un bajo impacto tanto al ambiente como a la salud del operador. Dentro de este enfoque, el crioarenado es una metodología de interés a emplear en la limpieza de materiales de construcción como ser rocas y cerámicos. El crioarenado, técnica conocida para propósitos de limpieza industrial, ha sido utilizada ocasionalmente en el campo del patrimonio cultural alcanzando resultados irregulares. Las ventajas de esta técnica son la ausencia de residuos producidos durante la limpieza, bajo riesgo ambiental y de salud, y finalmente el bajo costo de los “pellets” de impacto. La finalidad de la investigación encarada es definir parámetros correctos para un uso apropiado del crioarenado, como son los materiales del substrato, depósitos a eliminar y condiciones climáticas. Los efectos de la limpieza y los cambios morfológicos inducidos en diferentes substratos se investigaron por microscopia óptica y electrónica de barrido. Los resultados preliminares muestran que la eficiencia de limpieza se ve fuertemente afectada por la textura y composición mineralógica de los substratos colonizados

    Water chemistry and endangered white-clawed crayfish: A literature review and field study of water chemistry association in Austropotamobius pallipes

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    Populations of the endangered white-clawed crayfish (Austropotamobius pallipes) have rapidly declined in distribution and density in recent decades as a result of invasive crayfish, disease and habitat degradation. The species is thought to be particularly sensitive to water chemistry, and has been proposed as a bio-indicator of water quality. Here we detail the results of a systematic review of the literature regarding the chemistry of waterbodies inhabited by white-clawed crayfish, along with a wide-scale field study of the chemistry of crayfish-inhabited waterbodies in the UK. We use these data to examine potentially significant variables influencing crayfish distribution. Several variables appear to have thresholds that affect crayfish distribution; crayfish presence was associated with high dissolved oxygen, low conductivity, ammonium, sodium, and phosphate, and to a lesser extent low sulphate, nitrate, and total suspended solids. Some variables (magnesium, potassium, sodium, sulphate, nitrate, and total suspended solids) may be tolerated at moderate to high concentrations in isolation (indicated by the presence of some populations in high levels of these variables), but suites of chemical conditions may act synergistically in situ and must be considered together. Recent efforts to conserve white-clawed crayfish have included relocations to Ark Sites; novel protected habitats with reduced risk of the introduction of disease, invasive crayfish and habitat degradation. We use our findings to propose the first detailed guidelines for common water chemistry variables of potential Ark Sites for the conservation of the species throughout its European range

    Business Value Is not only Dollars - Results from Case Study Research on Agile Software Projects

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    Business value is a key concept in agile software development. This paper presents results of a case study on how business value and its creation is perceived in the context of agile projects. Our overall conclusion is that the project participants almost never use an explicit and structured approach to guide the value creation throughout the project. Still, the application of agile methods in the studied cases leads to satisfied clients. An interesting result of the study represents the fact that the agile process of many projects differs significantly from what is described in the agile practitioners’ books as best practices. The key implication for research and practice is that we have an incentive to pursue the study of value creation in agile projects and to complement it by providing guidelines for better client’s involvement, as well as by developing structured methods that will enhance the value-creation in a project
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