403 research outputs found

    Cal Poly Supermileage Electric Vehicle Drivetrain and Motor Control Design

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    The Cal Poly Supermileage Vehicle team is a multidisciplinary club that designs and builds high efficiency vehicles to compete internationally at Shell Eco-Marathon (SEM). Cal Poly Supermileage Club has been competing in the internal combustion engine (ICE) category of the competition since 2007. The club has decided it is time to expand their competition goals and enter their first battery electric prototype vehicle. To this end, a yearlong senior design project was presented to this team of engineers giving us the opportunity to design an electric powertrain with a custom motor controller. This system has been integrated into Ventus, the 2017 Supermileage competition car, bringing it back to life as E-Ventus for future competitions. The scope of this project includes sizing a motor, designing the drivetrain, programing the motor driver, building a custom motor controller, and finally mounting all these components into the chassis. The main considerations in this design are the energy efficiency measured in distance per power used (mi/kWh) and the whole system reliability. Driven train system reliability has been defined as the car starts the first time every time and can complete two competition runs of 6.3 miles each without mechanical or electrical failure. Drivetrain weight target was less than 25 pounds, and the finished system came in at 20 lbs 4 oz. Due to the design difficulties of the custom controller, three iterations were able to be produced by the end of this project, but there will need to be further iterations to complete the controller. Because of these difficulties our sponsor, Will Sirski, and club advisor, Dr. Mello, have agreed that providing the club with a working mechanical powertrain, powertrain data from the club chassis dynamometer using the programmed TI evaluation motor controller board, and providing board layout for the third iteration design for the custom controller satisfy their requirements for this project

    Biochemical characterisation of Murray Valley encephalitis virus proteinase

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    AbstractMurray Valley encephalitis virus (MVEV) is a member of the flavivirus group, a large family of single stranded RNA viruses, which cause serious disease in all regions of the world. Its genome encodes a large polyprotein which is processed by both host proteinases and a virally encoded serine proteinase, non-structural protein 3 (NS3). NS3, an essential viral enzyme, requires another virally encoded protein cofactor, NS2B, for proteolytic activity. The cloning, expression and biochemical characterisation of a stable MVEV NS2B–NS3 fusion protein is described

    Stochastic stability of uncertain Hopfield neural networks with discrete and distributed delays

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    This is the post print version of the article. The official published version can be obtained from the link below - Copyright 2006 Elsevier Ltd.This Letter is concerned with the global asymptotic stability analysis problem for a class of uncertain stochastic Hopfield neural networks with discrete and distributed time-delays. By utilizing a Lyapunov–Krasovskii functional, using the well-known S-procedure and conducting stochastic analysis, we show that the addressed neural networks are robustly, globally, asymptotically stable if a convex optimization problem is feasible. Then, the stability criteria are derived in terms of linear matrix inequalities (LMIs), which can be effectively solved by some standard numerical packages. The main results are also extended to the multiple time-delay case. Two numerical examples are given to demonstrate the usefulness of the proposed global stability condition.This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grant GR/S27658/01, the Nuffield Foundation of the UK under Grant NAL/00630/G, and the Alexander von Humboldt Foundation of Germany

    On global asymptotic stability of neural networks with discrete and distributed delays

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    This is the post print version of the article. The official published version can be obtained from the link below - Copyright 2005 Elsevier Ltd.In this Letter, the global asymptotic stability analysis problem is investigated for a class of neural networks with discrete and distributed time-delays. The purpose of the problem is to determine the asymptotic stability by employing some easy-to-test conditions. It is shown, via the Lyapunov–Krasovskii stability theory, that the class of neural networks under consideration is globally asymptotically stable if a quadratic matrix inequality involving several parameters is feasible. Furthermore, a linear matrix inequality (LMI) approach is exploited to transform the addressed stability analysis problem into a convex optimization problem, and sufficient conditions for the neural networks to be globally asymptotically stable are then derived in terms of a linear matrix inequality, which can be readily solved by using the Matlab LMI toolbox. Two numerical examples are provided to show the usefulness of the proposed global stability condition.This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grant GR/S27658/01, the Nuffield Foundation of the UK under Grant NAL/00630/G, and the Alexander von Humboldt Foundation of Germany

    State estimation for jumping recurrent neural networks with discrete and distributed delays

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    This is the post print version of the article. The official published version can be obtained from the link - Copyright 2009 Elsevier LtdThis paper is concerned with the state estimation problem for a class of Markovian neural networks with discrete and distributed time-delays. The neural networks have a finite number of modes, and the modes may jump from one to another according to a Markov chain. The main purpose is to estimate the neuron states, through available output measurements, such that for all admissible time-delays, the dynamics of the estimation error is globally asymptotically stable in the mean square. An effective linear matrix inequality approach is developed to solve the neuron state estimation problem. Both the existence conditions and the explicit characterization of the desired estimator are derived. Furthermore, it is shown that the traditional stability analysis issue for delayed neural networks with Markovian jumping parameters can be included as a special case of our main results. Finally, numerical examples are given to illustrate the applicability of the proposed design method.This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grants GR/S27658/01, an International Joint Project sponsored by the Royal Society of the UK, the National Natural Science Foundation of China under Grants 60774073 and 60804028, the Natural Science Foundation of Jiangsu Province of China under Grant BK2007075, and the Alexander von Humboldt Foundation of Germany

    Exploring autistic adults' psychosocial experiences affecting beginnings, continuity and change in camouflaging over time: A qualitative study in Singapore

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    Over their lifetimes, many autistic people learn to camouflage (hide or mask) their autism-related differences to forge relationships, find work and live independently in largely non-autistic societies. Autistic adults have described camouflaging as a 'lifetime of conditioning . . . to act normal' involving 'years of effort', suggesting that camouflaging develops over an autistic person's lifetime and may start early on, in childhood or adolescence. Yet, we know very little about why and how autistic people start to camouflage, or why and how their camouflaging behaviours continue or change over time. We interviewed 11 Singaporean autistic adults (9 male, 2 female, 22-45 years old) who shared their camouflaging experiences. We found that autistic adults' earliest motivations to camouflage were largely related to the desire to fit in and connect with others. They also camouflaged to avoid difficult social experiences (such as being teased or bullied). Autistic adults shared that their camouflaging behaviours became more complex and that, for some, camouflaging became a part of their self-identity over time. Our findings suggest that society should not pathologise autistic differences, but instead accept and include autistic people, to reduce the pressure on autistic people to hide who they truly are

    Tree transpiration and urban temperatures: current understanding, implications, and future research directions

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    The expansion of an urban tree canopy is a commonly proposed nature-based solution to combat excess urban heat. The influence trees have on urban climates via shading is driven by the morphological characteristics of trees, whereas tree transpiration is predominantly a physiological process dependent on environmental conditions and the built environment. The heterogeneous nature of urban landscapes, unique tree species assemblages, and land management decisions make it difficult to predict the magnitude and direction of cooling by transpiration. In the present article, we synthesize the emerging literature on the mechanistic controls on urban tree transpiration. We present a case study that illustrates the relationship between transpiration (using sap flow data) and urban temperatures. We examine the potential feed backs among urban canopy, the built environment, and climate with a focus on extreme heat events. Finally, we present modeled data demonstrating the influence of transpiration on temperatures with shifts in canopy extent and irrigation during a heat wave.Published versio
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