In this thesis, a low overhead transport protocol for Linux networking is proposed. This proposed protocol is motivated by the observation that the transport protocol for Linux requires more than a single memory copy for both the receiving and transmission of a packet, which is essentially redundant. In this thesis, we show that all but one of the memory copies can be eliminated, thus reducing the number of memory copies to one and only one, which is in general referred to as zero copy.

Thesis (Ph. D.)--University of Queensland, 2001. / Includes bibliographical references.

No description available.

No description available.

Many industrial workplaces involve tasks that require work to be performed in overhead postures. Epidemiological evidence suggests that working in these unavoidable, awkward postures leads to development of shoulder fatigue, pain and several musculoskeletal disorders. The accumulation of localized muscle fatigue has been strongly associated with the development of work-related musculoskeletal injuries (Armstrong et al., 1993). In order to prevent injury, minimizing muscular fatigue during short-cycled, repetitive work through different work organization schemes has been suggested (Dempsey et al., 2010). Previous research has examined the interactive effect of altering contraction level, duty cycle and cycle times on shoulder muscle fatigue. However, isolation of one factor while maintaining a constant workload has not been examined for overhead work tasks. The purpose of the study was to determine whether cycle time affected the progression of fatigue at the shoulder since the postural load during overhead tasks is inherently fatiguing. Ten university aged females performed a task rotation between an intermittent overhead pressing task and a neutrally located assembly task. Four conditions were defined by cycle time (15s, 30s, 60s and 120s) and each cycle consisted of one complete rotation. In order to quantify the progression of fatigue over time, four dependant measures were systematically collected for all conditions until exhaustion or to a maximum of three hours. These included root mean square (RMS) amplitude and median power frequency (MdPF) calculated from surface electromyography of nine muscles surrounding the shoulder, static strength capability, and rating of perceived exertion. Endurance time was also included as a fifth measure of fatigue. Linear regression was used to determine the slope of static strength and perceived exertion over time, and magnitude changes over normalized time were calculated for EMG measures. For all dependant measures, repeated measures ANOVA were used to identify significant differences across conditions. As the only independent factor investigated, cycle time influenced two out of the five dependent measures. Conditions induced differences in endurance time (F[3,24]=3.96, p=0.02) and RMS amplitude of the middle (F[24,189]=3.10, p<0.0001) and posterior deltoid (F[24,189]=2.52, p=0.0003). Performing overhead work in long cycles (120s) induced a shorter average endurance time (118.67min), and the shortest cycle time (15s) resulted in a longer average endurance time (152.44min). Over time, the rate of increase in RMS amplitude of both deltoid muscles was higher when working at the longest cycle time (120s). Although six muscles showed an indication of fatigue through significant decreases in MdPF in at least one condition, cycle time did not affect MdPF over time for any muscle examined. Similarly, the rate of static strength capability and rating of perceived exertion over time were not affected by cycle time. Two of five measures indicated that cycle time played a significant role in fatigue progression, making its effectiveness as a work organizational method for overhead work tasks unclear. Results indicate that that intermittent overhead work should be performed in shorter cycles to reduce the risk of shoulder injury. Identifying additional effects of cycle time on fatigue measures through increasing statistical power would provide ergonomists with more confidence in recommending this organizational strategy to mitigate the risk of musculoskeletal injury.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 87-88). Also available via the Internet.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 354-360). Also available via the Internet.

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on June 29, 2010). Bibliography: leaves 136-140.

Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2009. / Full text also available online. Scroll down for electronic link.

Στην παρούσα διπλωματική εργασία μελετάται η συμπεριφορά ενός μοντέλου γερανογέφυρας με την επιβολή ελέγχου με ανατροφοδότηση. Σκοπός μας μια κατά το δυνατόν βελτιστοποιημένη λύση του προβλήματος των ταλαντώσεων μέσω ενός αξιόπιστου, στιβαρού ελεγκτή, που να μπορεί να επιφέρει ακριβέστερη, ταχύτερη και ασφαλέστερη μετακίνηση των υλικών. Οι ελεγκτές που χρησιμοποιούμε είναι απλοί PD και PI ελεγκτές με την προσθήκη επίσης ενός μη γραμμικού ελεγκτή που βοηθά στην αύξηση της απόσβεσης των ταλαντώσεων. Επίσης με τη χρήση ενός περιοριστή ταυτόχρονα με τους άνω ελεγκτές, εξετάζουμε την συμπεριφορά του συστήματος με φραγμένη είσοδο. Ακόμα γίνεται αναφορά στους σύγχρονους τρόπους οδήγησης και πέδης AC και DC συστημάτων. / This diploma thesis forms a study on the behavior of an overhead crane after the implementation of o closed loop control law. Our goal is an optimized solution for the oscillation problem through a reliable, robust controller, who will be able to move cargos with precision, velocity and enhanced safety. The controllers used are simple PD and PI controllers with the addition of a nonlinear controller who will assist in raising the dumping value of the system. A limiter paired with the controllers above will help us evaluate the behavior of our system under a bound drive. There is also a citation of the current high-end drive and break solutions on AC and DC crane systems.