790 research outputs found

    Change Detection Analysis of the Landuse and Landcover of the Fort Cobb Reservoir Watershed

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    Department of Geograph

    A Privacy Type System for Context-aware Mobile Ambients

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    Thanks to the advances in technologies, ubiquitous computing (ubicomp) is developing fast with the proliferation of smart devices such as smart phones and tablet computers. However, privacy is an important concern in ubicomp; unless users are confident enough that their privacy is protected, many will be deterred from using such systems. This paper proposes a privacy type system that controls the behaviour of concurrent, context-aware and mobile processes to ensure that private information are not accidentally disclosed. We prove the subject reduction property, which guarantees that a well-typed process is safe and cannot disclose private information to an unauthorised party

    Parametric resonance in the Rayleigh-Duffing oscillator with time-delayed feedback

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    We investigate the principal parametric resonance of a Rayleigh–Duffing oscillator with time-delayed feedback position and linear velocity terms. Using the asymptotic perturbation method, we obtain two slow flow equations on the amplitude and phase of the oscillator. We study the effects of the frequency detuning, the deterministic amplitude, and the time-delay on the dynamical behaviors, such as stability and bifurcation associated with the principal parametric resonance. Moreover, the appropriate choice of the feedback gain and the time-delay is discussed from the viewpoint of vibration control. It is found that the appropriate choice of the time-delay can broaden the stable region of the non-trivial steady-state solutions and enhance the control performance. Theoretical stability analysis is verified through a numerical simulation.The University of Pretoriahttp://www.elsevier.com/locate/cnsnsai201

    Incidence and prevalence of Alcohol and Tobacco use on an Appalachian University Campus: an Epidemiologic Approach

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    A report submitted by Youmasu J. Siewe to the Research and Creative Production Committee in October of 1998 on alcohol and tobacco use at Morehead State University in the spring of 1998

    Formal Specification of CA-UCON model using CCA

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    A Context-Aware Usage CONtrol (CAUCON) model is an extension of the traditional UCON model which enables adaptation to environmental changes in the aim of preserving continuity of usage in a pervasive computing system. When the authorisations and obligations requirements are met by the subject and the object, and the conditions requirements fail due to changes in the environment or the system context, CAUCON model triggers specific actions to adapt to the new situation. Besides the data protection, CA-UCON model so enhances the quality of services, striving to keep explicit interactions with the user at a minimum. This paper proposes a formal specification of the CA-UCON model in the Calculus of Context-aware Ambients (CCA in short). This enables formal analysis of the CA-UCON model using the execution environment of CCA. For illustration, some properties of the CA-UCON model are validated for a ubiquitous learning system

    Formal Specification of a Context-aware Whiteboard System in CCA

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    A context-aware whiteboard system provides a number of services in a smart classroom including registering students as they enter the classroom; logging students and lecturers in to the blackboard virtual learning environment at the beginning of each lecture and logging them out at the end of the lecture. This system also notifies students of their absence to a lecture and maintains a list of attendance automatically. Using information from the timetable, it is aware of the lectures that are scheduled to take place in the classroom and the students that are allowed to attend these lectures. Finally, it allows students and lecturers to interact with teaching materials such as lecture slides and videos stored in the blackboard virtual learning environment. This paper proposes a formal specification of the white board system in the Calculus of Context-aware Ambients (CCA in short). This enables the formal analysis of the white board system using the execution environment of CCA. Some important properties of a classroom white board system have been validated as a proof of concept

    Health implications of secondhand smoke

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    The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

    Stress: Dealing with the inevitable

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    The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

    HLA-Phänotypfrequenzen bei Patienten mit intrakraniellen Aneurysmen

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    Subarachnoidale Blutungen (SAB) aufgrund eines intrakraniellen Aneurysmas (IA) sind mit einer hohen Morbidität und Mortalität behaftet. Bei einigen Patienten wird IA jedoch als Zufallsbefund festgestellt. Bei diesen Patienten stellt sich die Frage nach der geeigneten Behandlung, um eine drohende Blutung abzuwenden. Hierbei müssen Blutungsrisiko gegen operatives Risiko abgewogen werden. Daher ist aus klinischer Sicht von größter Bedeutung, einen Marker oder eine Marker-Kombination zu etablieren, durch die Patienten mit hohem Risiko für eine SAB identifiziert werden können. Das gehäufte familiäre Auftreten von IA sowie die Assoziation von IA mit Erkrankungen, die genetisch mitbedingt werden, deuten auf genetische Komponenten in der Ätiopathogenese von IA hin. Diese Komponenten werden von Genorten kodiert, die u.a. auf Chromosom 6p lokalisiert sind. Diese Chromosomen tragen die Genorte des HLA-Systems. Aus Untersuchungen von Patienten mit Bauchaortenaneurysmen ist bereits eine Assoziation zu HLA-Allelen bekannt. Weiterhin vermuten mehrere Studien eine Beziehung zwischen HLA und IA. Im Rahmen dieser Doktorarbeit wurden mit Hilfe der molekulargenetischen Methode 194 nicht vorselektierte IA-Patienten untersucht. Die Allelfrequenzen der IA-Patienten wurden mit den Allelfrequenzen von 174 Kontrollen verglichen. Signifikant erniedrigte Frequenzen des HLA-DQB1*0603 lagen bei IA-Patienten vor. Bei Patienten mit nicht rupturierten IA waren die Allele HLA-B62, -Cw*16 und -DRB1*07 signifikant erhöht. Das HLA-Cw*06 war signifikant erhöht in der SAB-Patientengruppe. Aufgrund dieser neuen Erkenntnisse lassen sich folgende Aufgabenstellungen dieser Doktorarbeit klären: Es ist noch wahrscheinlicher, dass HLA mit IA assoziiert ist; dass bestimmte erworbene Risikofaktoren mit IA assoziiert sind; dass sich die Verteilung von HLA-Merkmalen bei IA-Patienten mit und ohne SAB unterscheidet. Diese Arbeit lässt die Etablierung einer Marker-Kombination, die den Einfluss von HLA, VEGF, Kollagenen, „Candidate genes“ und NK-Zellrezeptoren u.a. auf IA berücksichtigt, noch wahrscheinlicher erscheinen. Deshalb empfiehlt es sich, Analysen dieser Faktoren bei einer größeren IA-Patientengruppe durchzuführen

    On Recommendation of Learning Objects using Felder-Silverman Learning Style Model

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The e-learning recommender system in learning institutions is increasingly becoming the preferred mode of delivery, as it enables learning anytime, anywhere. However, delivering personalised course learning objects based on learner preferences is still a challenge. Current mainstream recommendation algorithms, such as the Collaborative Filtering (CF) and Content-Based Filtering (CBF), deal with only two types of entities, namely users and items with their ratings. However, these methods do not pay attention to student preferences, such as learning styles, which are especially important for the accuracy of course learning objects prediction or recommendation. Moreover, several recommendation techniques experience cold-start and rating sparsity problems. To address the challenge of improving the quality of recommender systems, in this paper a novel recommender algorithm for machine learning is proposed, which combines students actual rating with their learning styles to recommend Top-N course learning objects (LOs). Various recommendation techniques are considered in an experimental study investigating the best technique to use in predicting student ratings for e-learning recommender systems. We use the Felder-Silverman Learning Styles Model (FSLSM) to represent both the student learning styles and the learning object profiles. The predicted rating has been compared with the actual student rating. This approach has been experimented on 80 students for an online course created in the MOODLE Learning Management System, while the evaluation of the experiments has been performed with the Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). The results of the experiment verify that the proposed approach provides a higher prediction rating and significantly increases the accuracy of the recommendation
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