1,618 research outputs found

    Path Tracking Control for Autonomous Driving Applications

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    Autonomous or self-driving vehicles are becoming a consolidate reality that involves both industrial and academic elds also for its impact in social and governmental communities, well far from automotive engineering. The intent of the present paper is to design an automatic steering control for an autonomous vehicle equipped with steer-by-wire and drive-by-wire technologies. The steering action is calculated to let the vehicle follow a reference path which is stored in a Digital Map properly built to be available in real-time. A Proportional + Derivative (PD) control strategy is deigned based on the Parameter State Approach (PSA) and it is coupled with a Feedforward (FF) term for improving the path tracking control in cornering maneuvers. Some experimental results are shown to demonstrates the ecacy of the controller presented

    Visualizing Rank Deficient Models: A Row Equation Geometry of Rank Deficient Matrices and Constrained-Regression

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    Situations often arise in which the matrix of independent variables is not of full column rank. That is, there are one or more linear dependencies among the independent variables. This paper covers in detail the situation in which the rank is one less than full column rank and extends this coverage to include cases of even greater rank deficiency. The emphasis is on the row geometry of the solutions based on the normal equations. The author shows geometrically how constrained-regression/generalized-inverses work in this situation to provide a solution in the face of rank deficiency

    Centre selection for clinical trials and the generalisability of results: a mixed methods study.

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    BACKGROUND: The rationale for centre selection in randomised controlled trials (RCTs) is often unclear but may have important implications for the generalisability of trial results. The aims of this study were to evaluate the factors which currently influence centre selection in RCTs and consider how generalisability considerations inform current and optimal practice. METHODS AND FINDINGS: Mixed methods approach consisting of a systematic review and meta-summary of centre selection criteria reported in RCT protocols funded by the UK National Institute of Health Research (NIHR) initiated between January 2005-January 2012; and an online survey on the topic of current and optimal centre selection, distributed to professionals in the 48 UK Clinical Trials Units and 10 NIHR Research Design Services. The survey design was informed by the systematic review and by two focus groups conducted with trialists at the Birmingham Centre for Clinical Trials. 129 trial protocols were included in the systematic review, with a total target sample size in excess of 317,000 participants. The meta-summary identified 53 unique centre selection criteria. 78 protocols (60%) provided at least one criterion for centre selection, but only 31 (24%) protocols explicitly acknowledged generalisability. This is consistent with the survey findings (n = 70), where less than a third of participants reported generalisability as a key driver of centre selection in current practice. This contrasts with trialists' views on optimal practice, where generalisability in terms of clinical practice, population characteristics and economic results were prime considerations for 60% (n = 42), 57% (n = 40) and 46% (n = 32) of respondents, respectively. CONCLUSIONS: Centres are rarely enrolled in RCTs with an explicit view to external validity, although trialists acknowledge that incorporating generalisability in centre selection should ideally be more prominent. There is a need to operationalize 'generalisability' and incorporate it at the design stage of RCTs so that results are readily transferable to 'real world' practice

    A knowledge-based framework for service management

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    peer-reviewedThe purpose of this paper is to investigate how information and communication technologies are used for service standardisation, customisation, and modularisation by knowledge-intensive service firms through the development and empirical validation of a knowledge-based framework. This paper uses 59 in-depth interviews, observational data, and document analysis from case studies of three service-related departments in high-technology, multinational knowledge-intensive business services (KIBSs). Prior research does not conceptualise the relationships between service customisation, standardisation and modularisation. This paper seeks to overcome this gap by integrating insights from research on the role played by both knowledge and information and communication technologies (ICTs) to construct and validate a framework to deal with this gap. It outlines the implications for service firms' use of ICT to deal with increasing knowledge intensity as well as indicating the circumstances under which service knowledge is best customised, standardised and modularised. Further testing in other industries would prove useful in extending the usefulness and applicability of the findings. The originality of the paper lies in developing and validating the first framework to outline the relationship between how service knowledge is customised, standardised or modularised and indicating the associated issues and challenges. It emphasises the role of knowledge and technology. The value of this framework increases as more firms deal with increasing knowledge intensity in the services they provide and in their use of ICTs to reap the benefits of appropriate knowledge reuse.ACCEPTEDpeer-reviewe

    Konstruktivistische Ansätze in der Erwachsenenbildung und Weiterbildung

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    Theoretical approaches in the field of further education and advanced vocational training have to face multifaceted demands: the analysis of knowledge aquisition and knowledge transfer and its instructional support as well as the revealment of the mechanisms which influence further education on an organisational level in companies. This article describes, that herefore especially moderate constructivistic approaches are useful. After an introduction to the philosophical tradition of these approaches and important characteristics of adult learning, two examples of constructivistic models are being described particularly: The theory of situated learning environments and career counseling. Concluding it is shown, that a moderate constructive perspective fulfils important criteria for the theoretic modelling of further education processes.Theoretische Ansätze in der Erwachsenen- und insbesondere in der beruflichen Weiterbildung müssen sich vielfältigen Ansprüchen stellen: der Analyse des Wissenserwerbs und Wissenstransfers und seiner instruktionalen Unterstützung ebenso wie der Aufdeckung der Mechanismen, die in den Betrieben auf organisatorischer Ebene die Weiterbildung beeinflussen. In diesem Beitrag wird die Auffassung vertreten, daß dafür insbesondere liberalisierte konstruktivistische Ansätze gut geeignet sind. Nach einer Einführung in die philosophische Tradition dieser Ansätze und wichtiger Merkmale des Lernens im Erwachsenenalter werden zwei Beispiele konstruktivistischer Modelle genauer beschrieben: die Theorie situierter Lernumgebungen und das career counseling. Abschließend wird gezeigt, daß eine liberalisierte konstruktivistische Perspektive wichtige Kriterien für die theoretische Modellierung von Weiterbildungsprozessen erfüllt

    Parental rating of sleep in children with attention deficit/hyperactivity disorder

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    Objective: Sleep problems have often been associated with attention deficit/hyperactivity disorder (ADHD). Parents of those with ADHD and children with ADHD report sleep difficulties more frequently than healthy children and their parents. The primary objective of this paper is to describe sleep patterns and problems of 5 to 11-year-old children suffering from ADHD as described by parental reports and sleep questionnaires. Method: The study included 321 children aged 5–11 years (average age 8.4 years); 45 were diagnosed with ADHD, 64 had other psychiatric diagnoses, and 212 were healthy. One hundred and ninety-six of the test subjects were boys and 125 were girls. A semi-structured interview (Kiddie-SADS-PL) was used to DSM-IV diagnose ADHD and comorbidity in the clinical group. Sleep difficulties were rated using a structured sleep questionnaire (Children Sleep Behaviour Scale). Results: Children diagnosed with ADHD had a significantly increased occurrence of sleep problems. Difficulties relating to bedtime and unsettled sleep were significantly more frequent in the ADHD group than in the other groups. Children with ADHD showed prolonged sleep onset latency, but no difference was shown regarding numbers of awakenings per night and total sleep time per night. Comorbid oppositional defiant disorder appeared not to have an added effect on problematic behaviour around bedtime. Conclusion: Parents of children with ADHD report that their children do not sleep properly more often than other parents. The ADHD group report problems with bedtime resistance, problems with sleep onset latency, unsettled sleep and nightmares more often than the control groups. It may therefore be relevant for clinicians to initiate a closer examination of those cases reporting sleep difficulties

    An investigation of smartphone applications : exploring usability aspects related to wireless personal area networks, context-awareness, and remote information access

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    In this thesis we look into usability in the context of smartphone applications. We selected three research areas to investigate, namely Wireless Personal Area Networks, Context-awareness, and Remote Information Access. These areas are investigated through a series of experiments, which focuses on important aspects of usability within software applications. Additionally, we mainly use smartphone devices in the experiments. In experiment 1, Multi-Platform Bluetooth Remote Control, we investigated Wireless Personal Area Networks. Specifically, we implemented a system consisting of two clients, which were created for Java ME and Windows Mobile, and integrated with a server application installed on a Bluetooth-enabled laptop. For experiments 2 and 3, Context-aware Meeting Room and PainDroid: an Android Application for Pain Management, we looked closely at the research area of Contextawareness. The Context-aware Meeting Room was created to automatically send meeting participants useful meeting notes during presentations. In experiment 3, we investigated the use of on-device sensors for the Android platform, providing an additional input mechanism for a pain management application, where the accelerometer and magnetometer were used. Finally, the last research area we investigated was Remote Information Access, where we conducted experiment 4, Customised Android Home Screen. We created a system that integrated both a cloud-based server application and a mobile client running on the Android platform. We used the cloud-computing platform to provide context management features, such as the ability to store the user configuration that was automatically pushed to the mobile devices.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    What traits are carried on mobile genetic elements, and why?

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    Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes
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