357,939 research outputs found

    Two-Hop Routing with Traffic-Differentiation for QoS Guarantee in Wireless Sensor Networks

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    This paper proposes a Traffic-Differentiated Two-Hop Routing protocol for Quality of Service (QoS) in Wireless Sensor Networks (WSNs). It targets WSN applications having different types of data traffic with several priorities. The protocol achieves to increase Packet Reception Ratio (PRR) and reduce end-to-end delay while considering multi-queue priority policy, two-hop neighborhood information, link reliability and power efficiency. The protocol is modular and utilizes effective methods for estimating the link metrics. Numerical results show that the proposed protocol is a feasible solution to addresses QoS service differenti- ation for traffic with different priorities.Comment: 13 page

    A philosophical context for methods to estimate origin-destination trip matrices using link counts.

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    This paper creates a philosophical structure for classifying methods which estimate origin-destination matrices using link counts. It is claimed that the motivation for doing so is to help real-life transport planners use matrix estimation methods effectively, especially in terms of trading-off observational data with prior subjective input (typically referred to as 'professional judgement'). The paper lists a number of applications that require such methods, differentiating between relatively simple and highly complex applications. It is argued that a sound philosophical perspective is particularly important for estimating trip matrices in the latter type of application. As a result of this argument, a classification structure is built up through using concepts of realism, subjectivity, empiricism and rationalism. Emphasis is put on the fact that, in typical transport planning applications, none of these concepts is useful in its extreme form. The structure is then used to make a review of methods for estimating trip matrices using link counts, covering material published over the past 30 years. The paper concludes by making recommendations, both philosophical and methodological, concerning both practical applications and further research

    A philosophical context for methods to estimate origin-destination trip matrices using link counts.

    Get PDF
    This paper creates a philosophical structure for classifying methods which estimate origin-destination matrices using link counts. It is claimed that the motivation for doing so is to help real-life transport planners use matrix estimation methods effectively, especially in terms of trading-off observational data with prior subjective input (typically referred to as 'professional judgement'). The paper lists a number of applications that require such methods, differentiating between relatively simple and highly complex applications. It is argued that a sound philosophical perspective is particularly important for estimating trip matrices in the latter type of application. As a result of this argument, a classification structure is built up through using concepts of realism, subjectivity, empiricism and rationalism. Emphasis is put on the fact that, in typical transport planning applications, none of these concepts is useful in its extreme form. The structure is then used to make a review of methods for estimating trip matrices using link counts, covering material published over the past 30 years. The paper concludes by making recommendations, both philosophical and methodological, concerning both practical applications and further research

    Psychometric Evaluation of the Physical Activity Enjoyment Scale in Adults with Functional Limitations

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    Enjoyment is an important construct for understanding physical activity participation, and it has not been examined in adults with functional limitations. This secondary analysis reported the reliability and validity of the Physical Activity Enjoyment Scale (PACES) in a convenience sample of 40 adults with functional limitations. The participants completed the PACES, Center for Epidemiological Studies Depression Scale (CES-D), and the Late Life Function and Disability Instrument (LLFDI) prior to beginning a 12-week feasibility dance intervention study. Results indicated reliability as Cronbach\u27s alpha was .95 and mean inter-item correlation was .52. To further support reliability, homogeneity of the instrument was evaluated using item-to-total scale correlations. Homogeneity was supported as all items had corrected item-to-total correlations greater than .30. For validity, the PACES was significantly related to only the Physical Function component of the LLFDI (r = .38, p = .02), but not the CES-D. Exploratory factor analysis revealed a 3-factor structure that accounted for 73.76% of the variance. This feasibility intervention dance study represented the first attempt to examine the psychometric properties of the PACES in adults with functional limitations. The findings demonstrate support for the scale\u27s reliability and validity among adults with functional limitations. Results are informative as further psychometric testing of the PACES is recommended using randomized clinical trials with larger sample sizes. Enjoyment for physical activity is an important construct for understanding physical activity participation in adults with functional limitations
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