• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 708
  • 216
  • 202
  • 159
  • 115
  • 85
  • 73
  • 66
  • 47
  • 43
  • 33
  • 25
  • 23
  • 10
  • 8
  • Tagged with
  • 1922
  • 309
  • 243
  • 216
  • 174
  • 158
  • 157
  • 154
  • 153
  • 147
  • 145
  • 145
  • 142
  • 131
  • 127
  • 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.
41

Static Stability of Tension Leg Platforms

Xu, Ning 2009 May 1900 (has links)
The static stability of a Tension Leg Platform (TLP) with an intact tendon system is principally provided by its tendons and hence quite different from those of a conventional ship or even a floating structure positioned by its mooring system. Because small deformations in tendons are capable of providing sufficient righting moment to a TLP, the contribution from the inclination of its hull is relatively insignificant, especially when its tendon system is intact. When the tendon system of a TLP is completely damaged, the static stability of a TLP behaves and is calculated in a similar manner as those of a conventional ship. In the case of a TLP with a partially damaged tendon system, the stability of a TLP may be provided by the deformation of its tendons and to a certain extent the inclination of its hull. Several hurricanes in recent years have raised concerns about the feasibility and the robustness of the TLP concept in the deep water Gulf of Mexico. To the best of our knowledge, existing publications on the research of static stability of TLPs are limited. This study investigates the static stability of different types of TLPs representing those deployed in the Gulf of Mexico, under three different scenarios. That is, a TLP with 1) an intact tendon system, 2) a partially damaged tendon system, and 3) a completely damaged tendon system. The four different types of TLP chosen for this study are 1) a conventional four-leg TLP, 2) three-leg mini TLP, 3) extended four-leg TLP and 4) mini four-leg TLP. To avoid buckling and yielding occurring in a tendon, we define that the maximum righting moment provided by an intact or partially damaged tendon system is reached when the tension in one or more tendons on the down tension leg becomes zero or when the tension in one or more tendons on the up tension leg starts to yield. This definition leads us to identify the most dangerous (or vulnerable) directions of met-ocean conditions to a TLP with an intact or partially damaged tendon system. Hence, our finding may also be used in the study on the pitch/roll dynamic stability of a TLP. The righting moments of each TLP in the three different scenarios are respectively computed and compared with related wind-induce static upsetting moment at certain velocities. By comparing their ratios, the static stability of a TLP and the redundancy of its tendon system may be revealed, which has important implication to the design of a TLP.
42

Open Platform Semi-Passive Ultra High Frenquency Radio Frequency Identi

Li, Tzu Hao 20 June 2011 (has links)
Radio frequency identi cation (RFID) is a rapidly emerging technology that enables au- tomatic remote identi cation of objects. Passive and semi-passive RFID systems can be distinguished from other forms of wireless systems, because the RFID tags (transponders) communicate by way of backscatter. In addition, passive tags derive their energy from the RF energy emitted by the reader. RFID technology can provide a fully automated data capture and analysis system. Compared to a passive RFID system, an open platform semi-passive UHF RFID tag can provide identi cation, security, low-power (compared to a wireless sensor net- work(WSN)), medium range and medium processing speed. However, the eld of semi- passive RFID is still under development, and has yet there are no open development platforms available. This thesis develops a prototype of a semi-passive UHF RFID tag that is compatible with the leading UHF RFID standard EPCglobal Gen 2 Class 1. I alsot has the exible I2C and analog digital converter(ADC) interface, which allows the additional of external analog and digital sensors. The sensor data can be read by microcontroller and stored at memory. Standard reader can get sensor data by sending QUERY and READ command to tag. Test results of our open platform semi-passive UHF RFID tag demonstrated that it can achieve a read rate above 50% when an open platform semi-passive UHF RFID tag is placed four meters from the reader antenna and the reader output power is set to 21 dBm. In addition, the proposed semi-passive open platform RFID tag consumes very little power (4.9 mA in 2V with system frequency set to 8MHz).
43

Exercise Monitor on E-healthcare System

Liang, Xiaojie January 2012 (has links)
With the rapid development of terminal hardware, mobile users and network environments, the scale of the mobile Internet appears to be catching up with the desktop Internet. Positioning System, phone sensors and applications which are able to be used anywhere have caused the arrival and increase in usage of the smart phone, and the world has become mobile-first. Within medical fields, the smart phone is also regarded as an acceptableassistant for nurses and patients as based on the advantages of mobile Internet. It is possible for healthcare personnel to assign tasks for the patients from a different place if there is a computer connected to the Internet. In addition,the smart phones is able to act as a nurse and remind the patients to complete their tasks. Accordingly, it has become a necessity to achieve this electronic healthcare system for hospitals. The objective of this research project is to summarize the procedures of this development, and release the relevant software based on an Android platform. Additionally, a corresponding website is to be designed so that healthcare personnel are able to sign in in order to deal with the tasks. The entire system has been tested in real scenarios, at this point only by the authorbut has still not been used by other organizations. The final part of the report involves the conclusions drawn and provides suggestions for further work about the whole project.
44

Open Platform Semi-Passive Ultra High Frenquency Radio Frequency Identi

Li, Tzu Hao 20 June 2011 (has links)
Radio frequency identi cation (RFID) is a rapidly emerging technology that enables au- tomatic remote identi cation of objects. Passive and semi-passive RFID systems can be distinguished from other forms of wireless systems, because the RFID tags (transponders) communicate by way of backscatter. In addition, passive tags derive their energy from the RF energy emitted by the reader. RFID technology can provide a fully automated data capture and analysis system. Compared to a passive RFID system, an open platform semi-passive UHF RFID tag can provide identi cation, security, low-power (compared to a wireless sensor net- work(WSN)), medium range and medium processing speed. However, the eld of semi- passive RFID is still under development, and has yet there are no open development platforms available. This thesis develops a prototype of a semi-passive UHF RFID tag that is compatible with the leading UHF RFID standard EPCglobal Gen 2 Class 1. I alsot has the exible I2C and analog digital converter(ADC) interface, which allows the additional of external analog and digital sensors. The sensor data can be read by microcontroller and stored at memory. Standard reader can get sensor data by sending QUERY and READ command to tag. Test results of our open platform semi-passive UHF RFID tag demonstrated that it can achieve a read rate above 50% when an open platform semi-passive UHF RFID tag is placed four meters from the reader antenna and the reader output power is set to 21 dBm. In addition, the proposed semi-passive open platform RFID tag consumes very little power (4.9 mA in 2V with system frequency set to 8MHz).
45

Force Feedback Functions in Hexapod Robot Applications

Wu, Xian-Chern 02 September 2010 (has links)
none
46

Static Stability of Tension Leg Platforms

Xu, Ning 2009 May 1900 (has links)
The static stability of a Tension Leg Platform (TLP) with an intact tendon system is principally provided by its tendons and hence quite different from those of a conventional ship or even a floating structure positioned by its mooring system. Because small deformations in tendons are capable of providing sufficient righting moment to a TLP, the contribution from the inclination of its hull is relatively insignificant, especially when its tendon system is intact. When the tendon system of a TLP is completely damaged, the static stability of a TLP behaves and is calculated in a similar manner as those of a conventional ship. In the case of a TLP with a partially damaged tendon system, the stability of a TLP may be provided by the deformation of its tendons and to a certain extent the inclination of its hull. Several hurricanes in recent years have raised concerns about the feasibility and the robustness of the TLP concept in the deep water Gulf of Mexico. To the best of our knowledge, existing publications on the research of static stability of TLPs are limited. This study investigates the static stability of different types of TLPs representing those deployed in the Gulf of Mexico, under three different scenarios. That is, a TLP with 1) an intact tendon system, 2) a partially damaged tendon system, and 3) a completely damaged tendon system. The four different types of TLP chosen for this study are 1) a conventional four-leg TLP, 2) three-leg mini TLP, 3) extended four-leg TLP and 4) mini four-leg TLP. To avoid buckling and yielding occurring in a tendon, we define that the maximum righting moment provided by an intact or partially damaged tendon system is reached when the tension in one or more tendons on the down tension leg becomes zero or when the tension in one or more tendons on the up tension leg starts to yield. This definition leads us to identify the most dangerous (or vulnerable) directions of met-ocean conditions to a TLP with an intact or partially damaged tendon system. Hence, our finding may also be used in the study on the pitch/roll dynamic stability of a TLP. The righting moments of each TLP in the three different scenarios are respectively computed and compared with related wind-induce static upsetting moment at certain velocities. By comparing their ratios, the static stability of a TLP and the redundancy of its tendon system may be revealed, which has important implication to the design of a TLP.
47

Smart Card Information Sharing Platform towards Global Nomadic World

HATANAKA, Masayuki, YAMAMOTO, Shuichiro, SENDA, Shoichi, HASHIMOTO, Junko, NIWANO, Eikazu 01 April 2004 (has links)
No description available.
48

An advanced fuel cell simulator

Acharya, Prabha Ramchandra 01 November 2005 (has links)
Fuel cell power generation systems provide a clean alternative to the conventional fossil fuel based systems. Fuel cell systems have a high efficiency and use easily available hydrocarbons like methane. Moreover, since the by-product is water, they have a very low environmental impact. The fuel cell system consists of several subsystems requiring a lot of effort from engineers in diverse areas. Fuel cell simulators can provide a convenient and economic alternative for testing the electrical subsystems such as converters and inverters. This thesis proposes a low-cost and an easy-to-use fuel cell simulator using a programmable DC supply along with a control module written in LabVIEW. This simulator reproduces the electrical characteristics of a 5kW solid oxide fuel cell (SOFC) stack under various operating conditions. The experimental results indicate that the proposed simulator closely matches the voltage-current characteristic of the SOFC system under varying load conditions. Effects of non-electrical parameters like hydrogen flow rate are also modeled and these parameters are taken as dynamic inputs from the user. The simulator is customizable through a graphical user interface and allows the user to model other types of fuel cells with the respective voltage-current data. The simulator provides an inexpensive and accurate representation of a solid oxide fuel cell under steady state and transient conditions and can replace an actual fuel cell during testing of power conditioning equipment.
49

Design and Implementation of SoC Hardware-Software Co-design Platform

Leong, Mun-kit 14 February 2008 (has links)
Reconfigurable supercomputing has been used by many high-performance computer systems to accelerate the processing speed. Thus, it is the present trend to use the microprocessor to combine with reconfigurable FPGA as the embedded system platform. However, the hardware-software co-design and integration of embedded system become great challenges of the designer. Beside this, the communication between hardware and software is crucial for the system to be operated effectively. Our concept consists of the design of FPGA configuration, described in I-Link hardware/software integration, improve the communication among the hardware and software. Besides, by using command packet method, we put the data to multi-hardware through hardware management unit (HMU). While system is operated, The Boot Loader will set up TCB and HCB data structure through PSP. The PSP can be regarded as the important reference segment of messages switching among system and hardware/software. The HMU has data buffering and management ability which can let the processes more easy and smooth. We successfully accomplish a hardware-software integrated system in HSCP, which is developed in our laboratory. The basic components of our platform include ARM7TDMI CPU, memory and Altera ACEK 1K-100 of FPGA. By using ARM-code, we also preliminary accomplish the Boot Loader, HW Constructor and self-developed embedded system. Finally, we make use of a large amount of multiplication operation and matrix summation to verify the feasibility of this system architecture.
50

VMware - Windows im Fenster

Heik, Andreas 21 March 2000 (has links)
Auch eingefleischte LINUX-Nutzer bekommen mal eine eMail mit Wordanhang oder eine Coreldrawgrafik. Um Dokumente dieser Art anschauen zu können bleibt oft kein anderer Ausweg, als Windows zu booten. VMware bietet eine elegante Möglichkeit, mehrere Betriebssysteme auf einer Maschine gleichzeitig nutzen zu können. Natürlich sind dem Einsatz von VMware kaum Grenzen gesetzt.

Page generated in 0.0502 seconds