946 research outputs found

    On the theory of SODAR measurement techniques (final reporting on WP1, EU WISE project NNE5-2001-297)

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    The need for alternative means to measure the wind speed for wind energy purposes has increased with the increase of the size of wind turbines. The cost and the technical difficulties for performing wind speed measurements has also increased with the size of the wind turbines, since it is demanded that the wind speed has to be measured at the rotor center of the turbine and the size of both the rotor and the hub height have grown following the increase in the size of the wind turbines. The SODAR (SOund Detection And Ranging) is an alternative to the use of cup anemometers and offers the possibility of measuring both the wind speed distribution with height and the wind direction. At the same time the SODAR presents a number of serious drawbacks such as the low number of measurements per time period, the dependence of the ability to measure on the atmospheric conditions and the difficulty of measuring at higher wind speeds due to either background noise or the neutral condition of the atmosphere. Within the WISE project (EU project number NNE5-2001-297), a number of work packages have been defined in order to deal with the SODAR. The present report is the result of the work package 1. Within this package the objective has been to present and achieve the following: - An accurate theoretic model that describes all the relevant aspects of the interaction of the sound beam with the atmosphere in the level of detail needed for wind energy applications. - Understanding of dependence of SODAR performance on hard- and software configuration. - Quantification of principal difference between SODAR wind measurement and wind speed measurements with cup anemometers with regard to power performance measurements. The work associated to the above is described in the work program as follows: a) Draw up an accurate model of the theoretic background of the SODAR. The necessary depth is reached when the influences of various variables in the model on the accuracy of the measurement have been assessed. b) Describe the general algorithm SODAR uses for sending the beam and measuring the reflections. Describe the influence of various settings on the working of the algorithm. c) Using the data set from work package two analyse the differences between point measurements and profile measurements. All the above issues are addressed in the following repor

    UpWind: integrated wind turbine design - Salford final summary on WP 6.1, WP.6.2, WP 6.3 And WP 6.4

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    Within the Upwind project the University of Salford provided development work for SODAR instruments in relation to the next generation of wind turbines. The main focus of the work was on the identification and proposal of design improvements, the development of a calibration device and the novel design of a bi-static SODAR to overcome limitations in the use of remote sensing in complex terrain. Data accuracy and availability of SODARs suffers during rain. Therefore an algorithm to detect data affected by rain and to extract the wind information has been developed and successfully tested to determine the scope of the technique. In mountainous terrain another source of inaccurate wind estimates is the separation of measurement volumes which results in inaccuracy of up to 5%. A simple flow model has been proposed and evaluated for a case study showing that the applied corrections can improve accuracy. A calibration transponder and a new bi-static Sodar design with vertical transmission and three scanning receivers have been designed and successfully tested

    A Personalized Self-Management Rehabilitation System for Stroke Survivors: A Quantitative Gait Analysis Using a Smart Insole.

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    Background: In the United Kingdom, stroke is the single largest cause of adult disability and results in a cost to the economy of £8.9 billion per annum. Service needs are currently not being met; therefore, initiatives that focus on patient-centered care that promote long-term self-management for chronic conditions should be at the forefront of service redesign. The use of innovative technologies and the ability to apply these effectively to promote behavior change are paramount in meeting the current challenges. Objective: Our objective was to gain a deeper insight into the impact of innovative technologies in support of home-based, self-managed rehabilitation for stroke survivors. An intervention of daily walks can assist with improving lower limb motor function, and this can be measured by using technology. This paper focuses on assessing the usage of self-management technologies on poststroke survivors while undergoing rehabilitation at home. Methods: A realist evaluation of a personalized self-management rehabilitation system was undertaken in the homes of stroke survivors (N=5) over a period of approximately two months. Context, mechanisms, and outcomes were developed and explored using theories relating to motor recovery. Participants were encouraged to self-manage their daily walking activity; this was achieved through goal setting and motivational feedback. Gait data were collected and analyzed to produce metrics such as speed, heel strikes, and symmetry. This was achieved using a “smart insole” to facilitate measurement of walking activities in a free-living, nonrestrictive environment. Results: Initial findings indicated that 4 out of 5 participants performed better during the second half of the evaluation. Performance increase was evident through improved heel strikes on participants’ affected limb. Additionally, increase in performance in relation to speed was also evident for all 5 participants. A common strategy emerged across all but one participant as symmetry performance was sacrificed in favor of improved heel strikes. This paper evaluates compliance and intensity of use. Conclusion: Our findings suggested that 4 out of the 5 participants improved their ability to heel strike on their affected limb. All participants showed improvements in their speed of gait measured in steps per minute with an average increase of 9.8% during the rehabilitation program. Performance in relation to symmetry showed an 8.5% average decline across participants, although 1 participant improved by 4%. Context, mechanism, and outcomes indicated that dual motor learning and compensatory strategies were deployed by the participants

    On “The Analysis of Ranked Data Derived from Completely Randomized Factorial Designs”

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    Extensions of the Kruskal-Wallis procedure for a factorial design are reviewed and researched under various degrees and kinds of nonnullity. It was found that the distributions of these test statistics are a Function of effects other than those being tested except under the completely null situation and their use is discouraged.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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