This thesis presents a high efficiency RF to DC converter for RFID applications. The proposed circuit has been designed in 90 nm CMOS technology using a single RF source. It exploits an internal Vth cancellation technique along with a leakage current reducer. The circuit operates in two phases: Phase 1, applies a DC voltage between gate and drain to reduce the VDS of the PMOS transistor; and Phase 2 removes this DC voltage meanwhile by pulling the drain and source terminals of the same transistor to the same potential, reducing the sub-threshold leakage current and enhancing the power conversion efficiency. The simulation results show that high DC power up to 8.1µA can be delivered to the load. The PCE has been measured 36.3% at -14.3dBm and can be improved to 54.5% providing an impedance matching network between the source and rectifier input.

Hydraulic systems are complex dynamical systems whose performance can be degraded by certain faults, specifically internal or external leakage. The objective of this research is to develop an appropriate signal processing approach for detection and isolation of these faults. By analyzing the dynamics of the hydraulic actuator, an internal leakage is shown to increase the damping characteristic of the system and change the transient response of the pressure signals. An external leakage, on the other hand, drops the pressure signals without having a significant effect on transient responses. Offline detection of internal leakage in hydraulic actuators is first examined by using fast Fourier, wavelet and Hilbert-Huang transforms. The original pressure signal is decomposed using these transform methods and the frequency component which is sensitive to the internal leakage is identified. The root mean square of the processed pressure signal is used and a comparison of the three transforms is made to assess their ability to detect internal leakage fault, through extensive validation tests. The wavelet transform method is shown to be more suitable for internal leakage detection compared to the other two methods. The wavelet based approach is then extended to an online detection method of internal leakage fault. The online approach considers the more realistic case of an actuator that is driven in a closed-loop mode to track pseudorandom position reference inputs against a load emulated by a spring. Furthermore, the method is shown to remain effective even with control systems which are tolerant to leakage faults. Next, the application of wavelet transform to detect external leakage fault using both offline and online applications in hydraulic actuators is described. The method also examines the isolation of this fault from actuator internal leakage in a multiple-fault environment. The results show that wavelet transform is a fast and easily-implementable method for leakage detection in hydraulic actuators without any need to explicitly incorporate the model of actuator or leakage. Internal leakages as low as 0.124 lit/min, are shown to be detectable, for 80% of the times using structured input signal. For online application, internal leakages in the range of 0.2-0.25 lit/min can be identified. External leakages as low as 0.3 lit/min can be detected in all offline and online applications. Other methods such as observer based and Kalman filter methods, which require the model of the actuator or leakage fault, cannot report leakage detection of magnitudes as low as that reported in this work. The low leak rate detection and not requiring a model of the actuator or leakage make this method very attractive for industrial implementation.

Hydraulic systems are complex dynamical systems whose performance can be degraded by certain faults, specifically internal or external leakage. The objective of this research is to develop an appropriate signal processing approach for detection and isolation of these faults. By analyzing the dynamics of the hydraulic actuator, an internal leakage is shown to increase the damping characteristic of the system and change the transient response of the pressure signals. An external leakage, on the other hand, drops the pressure signals without having a significant effect on transient responses. Offline detection of internal leakage in hydraulic actuators is first examined by using fast Fourier, wavelet and Hilbert-Huang transforms. The original pressure signal is decomposed using these transform methods and the frequency component which is sensitive to the internal leakage is identified. The root mean square of the processed pressure signal is used and a comparison of the three transforms is made to assess their ability to detect internal leakage fault, through extensive validation tests. The wavelet transform method is shown to be more suitable for internal leakage detection compared to the other two methods. The wavelet based approach is then extended to an online detection method of internal leakage fault. The online approach considers the more realistic case of an actuator that is driven in a closed-loop mode to track pseudorandom position reference inputs against a load emulated by a spring. Furthermore, the method is shown to remain effective even with control systems which are tolerant to leakage faults. Next, the application of wavelet transform to detect external leakage fault using both offline and online applications in hydraulic actuators is described. The method also examines the isolation of this fault from actuator internal leakage in a multiple-fault environment. The results show that wavelet transform is a fast and easily-implementable method for leakage detection in hydraulic actuators without any need to explicitly incorporate the model of actuator or leakage. Internal leakages as low as 0.124 lit/min, are shown to be detectable, for 80% of the times using structured input signal. For online application, internal leakages in the range of 0.2-0.25 lit/min can be identified. External leakages as low as 0.3 lit/min can be detected in all offline and online applications. Other methods such as observer based and Kalman filter methods, which require the model of the actuator or leakage fault, cannot report leakage detection of magnitudes as low as that reported in this work. The low leak rate detection and not requiring a model of the actuator or leakage make this method very attractive for industrial implementation.

This project is a site specific based exploration into the boundaries between the domestic home and the navigation of the anxious corporeal body which dwells in the space. These connections open up ways of mapping anxiety brought on through intrusive thoughts surrounding contamination (in relation to Obsessive Compulsive Disorder). The corporal navigation of the domestic is fuelled by the thoughts and their control over the notions of fear and anxiety surrounding the transferring of contaminated material from the external temporal world (dust and organic matter) into the internal sterile environment through movement or fissures in the fabric of the dwelling. The project explores the notions of the domestic space being formed into a container for the intrusive thoughts through physical acts of decontaminating, containment, sealing and expelling the elements of dirt; the body and the home become a hybrid entity alluding to the extreme control which forms and takes over the domestic space.

Thesis (M.S.)--University of Michigan, 1968.

Thesis (M.S.)--University of Michigan, 1998. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1968.

Thesis (Ph. D.)--University of Hong Kong, 1994. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 2003. / Includes bibliographical references.

Covert channel attacks utilize shared resources to indirectly transmit sensitive information to unauthorized parties. Many current operating systems, such as SELinux, rely on generating labels based on a file's security classification and system-wide security policies and then binding these labels to all such files in the filesystem. Enforcement of security policies in such systems occurs at the time of access to a file or resource. Such mechanisms are flawed, however, in that they do not adequately protect against information laundering by means of covert channels. One recent development, Colored Linux, serves as an extension to SELinux and utilizes watermarking algorithms to "color" the contents of files with their respective security classification in order to enhance resistance to information laundering attacks. In this thesis, a mobile agent-based approach to implementing Colored Linux is proposed to automate the process of detecting and coloring receptive hosts' filesystems and to provide monitoring of the colored filesystem for instances of potential information leakage. Implementation details and execution results are included to illustrate the merits of the proposed approach. An evaluation of the performance of this agent-based system is conducted over a single host as well as a local network of machines and detailed here as well. Finally, third-party analysis of the agent system using formal methods is discussed.