• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2769
  • 1845
  • 916
  • 292
  • 291
  • 148
  • 78
  • 68
  • 66
  • 52
  • 47
  • 44
  • 43
  • 43
  • 43
  • Tagged with
  • 8242
  • 1083
  • 951
  • 739
  • 737
  • 643
  • 620
  • 613
  • 613
  • 594
  • 453
  • 429
  • 422
  • 421
  • 409
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Využití FPGA pro řízení a modelování BLDC motoru / FPGA application for control and modelling of BLDC motor

Sova, Václav January 2013 (has links)
Thesis deals with the challenges in the field of BLDC motors control with the utilization of Field Programmable Gate Arrays (FPGA). Using the modular dSPACE hardware with the FPGA board, these issues are solved: sensored and sensorless control, real-time simulation of BLDC motor and control of BLDC motor in degraded mode. FPGA design is made using the System Generator for DSP from Xilinx. The side effect of work is to show that with the expansion of high-level tools for FPGA design, the implementation of algorithms for FPGA is relatively quick and efficient and does not require years of experience and big knowledge of field programmable gate arrays. The implementation of algorithms on FPGA instead of processors brings many advantages, in the first place the high speed processing and low latency.
92

Analysis of the Relationship of Selected Abilities to Performance on a Gross Motor Task at Various Stages of Task Practice

Raducha, John Paul 12 1900 (has links)
The problem with which this investigation was concerned was that of determining the relationship of selected abilities to motor skill performance. Specifically this study analysed the performance trend on a gross motor task to determine the degree of relationship between the abilities: agility, balance, depth perception, flexibility, reaction time and speed of arm movement, and strength and performance scores on a wall volley task at successive stages of task practice.
93

Zigbee based wireless adjustable speed drive system

Moghe, Prajakta S. January 2016 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This thesis proposes a remotely controlled motor drive system which is able to supply a regulated voltage for both DC and AC motors. The proposed system integrates two different technologies, each of which belongs to the field of wireless communications and semiconductor power electronics. The introduction highlights the literature review and technical contributions in these two electrical engineering fields. The pulse width modulated control algorithm for speed control is discussed in detail. Incorporating the zigbee wireless technology into the motor drive system, for the speed control of an AC and a DC motor, by implementing digital pulse width modulation technique is the aim of this thesis. The main characteristics of the proposed system are: 1) its universal feature since it can feed either DC or AC motor without changing the hardware, 2) remotely controlled, which allows the end-user to control the motor speed safely from a remote distance, 3) flexibility in installation of the motor drives in areas that are not easily accessible by end-users, and 4) uninterrupted speed control for distance of up to few 100 feet.
94

RAPID ADAPTATION OF REACTIVE FORCE CONTROL WHEN LIFTING OBJECTS

Markovik, SIMONA 04 February 2013 (has links)
The control of object manipulation tasks involves the close interplay of predictive and reactive control mechanisms. For example, when lifting an object, people typically predict the weight based on object size and material as well as sensorimotor memory obtained from previous lifts of the object. When lifting objects with a precision grip, people increase vertical load force to a target level that slightly exceeds the predicted weight. When the object is heavier than expected, the mismatch between expected and actual tactile signals associated with lift-off triggers a corrective action within ~100 ms, that involves probing increases in load force that continue until the object is lifted. Here we investigated whether this correction action can be adaptively influenced by experience. Participants repeatedly lifted an object that was instrumented with force sensors to measure the forces applied by the fingertips, with weight that could be varied without the knowledge of the participant. In 80% of trials, the weight was set to 2 N and, in different blocks of 110 trials, the remaining 20 % of trials (2 trials randomly selected from each successive 10 trials) was set to either 4 or 6 N. We found that the rate of change of the reflexively triggered increase in load force that occurred in the 4 or 6 N trials, scaled with the additional weight. That is, following the initial increase in load force to ~2 N, the subsequent increase in load force was more rapid for the 6 N object than the 4 N object. In contrast, the onset time of the reactive increase in load force was independent of the additional weight. Finally, this adaptation of reactive load force control took place quickly and was evident after only a few lifts of the heavier weight. These results indicate that the reactive increases in load force that occur when a lifted object is heavier than expected can be adapted and tuned, to refine behavior. This further suggests that multiple predictions can be generated about object weight when lifting. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-02-02 13:34:20.533
95

Construção, acionamento e ensaios do motor bifásico de imã permanente no rotor (MBIPR) / not available

Borelli, Rafael 10 June 2005 (has links)
Visando uma opção de substituição, onde for possível e aplicável, do motor de indução monofásico, este trabalho relata o estudo teórico, a construção, o acionamento e os ensaios de um motor bifásico com ímã permanente no rotor, de baixa potência, utilizando imãs de ferrita na confecção do rotor. / This work shows the theoretical studies, building, driving systems and tests of a small-power double-phase motor with ferrite permanent-magnet in the rotor, based on the original structure of a single-phase induction motor. The objective is to create an option to replace the single-phase induction motor where it is possible and applicable.
96

Afferent modulation of human motor cortex excitability / by Julia Blanche Pitcher.

Pitcher, Julia Blanche January 2003 (has links)
"April 2003" / Bibliography: leaves 124-144. / xvii, 144 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Molecular and Biomedical Sciences, Discipline of Physiology, 2003
97

Proportional and non-proportional transfer of movement sequences

Wilde, Heather Jo 12 April 2006 (has links)
The ability of spatial transfer to occur in movement sequences is reflected upon in theoretical perspectives, but limited research has been done to verify to what extent spatial characteristics of a sequential learning task occur. Three experiments were designed to determine participants’ ability to transfer a learned movement sequence to new spatial locations. A 16-element dynamic arm movement sequence was used in all experiments. The task required participants to move a horizontal lever to sequentially projected targets. Experiment 1 included 2 groups. One group practiced a pattern in which targets were located at 20, 40, 60, and 80° from the start position. The other group practiced a pattern with targets at 20, 26.67, 60, and 80°. The results indicated that participants could effectively transfer to new target configurations regardless of whether they required proportional or non-proportional spatial changes to the movement pattern. Experiment 2 assessed the effects of extended practice on proportional and non-proportional spatial transfer. The data indicated that while participants can effectively transfer to both proportional and non-proportional spatial transfer conditions after one day of practice, they are only effective at transferring to proportional transfer conditions after 4 days of practice. The results are discussed in terms of the mechanism by which response sequences become increasingly specific over extended practice in an attempt to optimize movement production. Just as response sequences became more fluent and thus more specific with extended practice in Experiment 2, Experiment 3 tested whether this stage of specificity may occur sooner in an easier task than in a more difficult task. The 2 groups in Experiment 3 included a less difficult sequential pattern practiced over either 1 or 4 days. The results support the existence of practice improvement limitations based upon simplicity versus complexity of the task.
98

Proportional and non-proportional transfer of movement sequences

Wilde, Heather Jo 12 April 2006 (has links)
The ability of spatial transfer to occur in movement sequences is reflected upon in theoretical perspectives, but limited research has been done to verify to what extent spatial characteristics of a sequential learning task occur. Three experiments were designed to determine participants’ ability to transfer a learned movement sequence to new spatial locations. A 16-element dynamic arm movement sequence was used in all experiments. The task required participants to move a horizontal lever to sequentially projected targets. Experiment 1 included 2 groups. One group practiced a pattern in which targets were located at 20, 40, 60, and 80° from the start position. The other group practiced a pattern with targets at 20, 26.67, 60, and 80°. The results indicated that participants could effectively transfer to new target configurations regardless of whether they required proportional or non-proportional spatial changes to the movement pattern. Experiment 2 assessed the effects of extended practice on proportional and non-proportional spatial transfer. The data indicated that while participants can effectively transfer to both proportional and non-proportional spatial transfer conditions after one day of practice, they are only effective at transferring to proportional transfer conditions after 4 days of practice. The results are discussed in terms of the mechanism by which response sequences become increasingly specific over extended practice in an attempt to optimize movement production. Just as response sequences became more fluent and thus more specific with extended practice in Experiment 2, Experiment 3 tested whether this stage of specificity may occur sooner in an easier task than in a more difficult task. The 2 groups in Experiment 3 included a less difficult sequential pattern practiced over either 1 or 4 days. The results support the existence of practice improvement limitations based upon simplicity versus complexity of the task.
99

A comparison of steady state and transient emissions from a heavy-duty diesel engine

Bane, Bradley R. January 2002 (has links)
Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xiv, 173 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 158-160).
100

Tennis anticipation study

Li, Wing-fung, 李永豐 January 2005 (has links)
published_or_final_version / Sports Science / Master / Master of Science in Sports Science

Page generated in 0.0321 seconds