<p>The gastroduodenal junction coordination was studied by conducting experiments on six dogs. The electrical and mechanical signals in the gastroduodenal area were recorded by surgically implanting electrodes and strain gauges. Recordings were made on an analog tape recorder for about 30 minutes in the fasted state and for about 45 minuted after food or with intravenous infusion of pentagastrin. The recorded signals were later fed into Data General Nova 830 Minicomputer for subsequent analysis. In analysing these signals frequency is of prime importance as interaction could result in the argumentation of the proximal duodenal electrical/mechanical signal at antral frequency. The application of spectral analysis techniques for this purpose is described. The programs are developed for the following purposes:</p> <p>1) To accept the analog data and convert them into discrete digital data.</p> <p>2) To display any segment of data for visual observation of recorded signals.</p> <p>3) To compute the auto and cross power spectral density.</p> <p>The results of the analysis are presented in the form of tables. It is concluded that there exists a coordination. The possible mechanism could be myogenic, since coordination in the electrical activity is evident when atropine was given.</p> / Master of Engineering (ME)

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Electricity is a critical component in our daily life. Because it is almost always available, we take it for granted. However, given the proper conditions, blackouts do happen every once in a while and can cause discomfort at a minimum, and a catastrophe in rare circumstances. The largest blackouts typically include cascading failures, which are sequences of interdependent outages. Although timely and effective operator intervention can often prevent a cascade from spreading, such interventions require ample situational awareness. The goals of this dissertation are twofold: to provide power system operators with insight into the risk of blackouts given the space of potential initiating outages, and to evaluate control systems that might mitigate cascading failure risk. Accordingly, this dissertation proposes a novel method to estimate cascading failure risk. It is shown that this method is at least two orders of magnitude faster in estimating risk, compared with a traditional Monte-Carlo simulation in two test systems including a large-scale real power grid model. This method allows one to find critical components in a system and suggests ideas for how to reduce blackout risk by preventive measures, such as adjusting initial dispatch of a system. In addition to preventive measures, it is also possible to use corrective control strategies to reduce blackout sizes. These methods could be used once the system is under stress (for example if some of the elements are overloaded) to stop a potential cascade before it unfolds. This dissertation focuses on a distributed receding horizon model predictive control strategy to mitigate overloads in a system, in which each node can only control other nodes in its local neighborhood. A distributed approach not only needs less communication and computation, but is also a more natural fit with modern power system operations, in which many control centers manage disjoint regional networks. In addition, a distributed controller may be more robust to random failures and attacks. A central controller benefits from perfect information, and thus provides the optimal solution. This dissertation shows that as long as the local neighborhood of the distributed method is large enough, distributed control can provide high quality solutions that are similar to what an omniscient centralized controller could achieve, but with less communication requirements (per node), relative to the centralized approach.

In this work, a computationally efficient solution for constraint management of square multi-input multi-output (MIMO) systems is presented. The solution, referred to as the Decoupled Reference Governor (DRG), maintains the highly-attractive computational features of scalar reference governors (SRG) compared to Vector Reference Governor (VRG) and Command Governor (CG). This work focuses on square MIMO systems that already achieve the desired tracking performance. The goal of DRG is to enforce output constraints and simultaneously ensure that the degradation to tracking performance is minimal. DRG is based on decoupling the input-output dynamics of the system so that every channel of the system can be viewed as an independent input-output relationship, followed by the deployment of a bank of scalar reference governors for each decoupled channel. We present a detailed set-theoretic analysis of DRG, which highlights its main characteristics. A quantitative comparison between DRG, SRG, and the VRG is also presented in order to illustrate the computational advantages of DRG. Finally, a distillation process is introduced as an example to illustrate the applicability of DRG.

In automakers' never-ending quest to reduce emissions and improve performance, the turbocharger represents a major step in advancing these goals. By repurposing waste exhaust and compressing the air intake, they are able to increase overall power. One critical control loop in the turbocharger is control of boost pressure via the wastegate. This is a highly nonlinear process and experimental data has shown that a gain-scheduled PID (proportional integral derivative) controller developed with IMC (internal model control) tuning methodology is an effective means to control boost pressure. Motivated by this successful implementation of IMC-PID tuning in the automotive world, this work hopes to extend and analyze that framework. Traditionally, the success of an IMC controller depends on the accuracy of the plant model. This research challenges this view and investigates using IMC with a gain-integrator-delay (GID) model identified at a critical frequency, regardless of the actual plant. The GID model is useful because of its simplicity to characterize and its ability to be translated to the ubiquitous PID controller easily. Three design techniques are developed: (1) design for post-hoc tuning, (2) design for closed loop bandwidth, and (3) design for phase margin. In addition, these techniques are investigated via a Monte Carlo simulation to determine efficacy for when there exists plant/model mismatch. Finally, the three techniques are applied to control the speed of an inertia disk on the Quanser Servo 2 device.

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This thesis work builds upon the theoretical studies and full-wave analysis of radio frequency micro- and nano-electromechanical systems (RF M/NEMS) integrated multi-functional reconfigurable antennas(MRAs). This is a part of the overall M/NEMS research efforts performed in the RF NEMS Laboratory at USU, which includes design, microfabrication, test, and characterization of M/NEMS integrated congitive wireless communication systems (fig. A.1). The thesis work focuses on two MRAs. 1) A triple bands patch antenna which can operate at 800, 2400, and 4900 MHz in response to public safety wireless communication systems. 2) A multi-frequency multi-polarization MRA for wireless personal area networking application (WPAN) operating at 57-64 GHz frequency range

This work describes a novel frequency based Current to Digital converter, which would be fully realizable on a single chip. Biological systems make use of delay line techniques to compute many things critical to the life of an animal. Seeking to build up such a system, we are adapting the auditory localization circuit found in barn owls to detect and compute the magnitude of an input current. The increasing drive to produce ultra low-power circuits necessitates the use of very small currents. Frequently these currents need to accurately measured, but current solutions typically involve off-chip measurements. These are usually slow, and moving a current off chip increases noise to the system. Moving a system such as this completely on chip will allow for precise measurement and control of bias currents, and it will allow for better compensation of some common transistor mismatch issues. This project affords an extremely low power (100s nW) converter technology that is also very space efficient. The converter is completely asynchronous which yields ultra-low power standby operation [1].

The multi-service requirements of the 3G and 4G communication systems, and their backward compatibility requirements, create challenges for the antenna and RF front-end designs with multi-band and wide-band techniques. These challenges include: multiple filters, which are lossy, bulky, and expensive, are needed in the system; device board size limitation and the associated isolation problems caused by the limited space and crowd circuits; and the insertion loss issues created by the single-pole-multi-through antenna switch. As will be shown, reconfigurable antennas can perform portions of the filter functions, which can help solve the multiple filters problem. Additionally, reconfigurable RF circuits can decrease the circuit size and output ports, which can help solve board size limitation, and isolation and antenna switch insertion loss issues. To validate the idea that reconfigurable antennas and reconfigurable RF circuits are a viable option for multi-service communication system, a reconfigurable patch antenna, a reconfigurable monopole antenna, and a reconfigurable power amplifier (PA) have been developed. All designs adapt state-of-the-art techniques. For the reconfigurable antenna designs, an experiment demonstrating its advantages, such as jamming signal resistance, has been performed. Reconfigurable antennas provide a better out-ofoperating- band noise performance than the multi-band antennas design, decreasing the need for filters in the system. A full investigation of reconfigurable antennas, including the single service reconfigurable antenna, the mixed signal service reconfigurable antenna, and the multi-band reconfigurable antenna, has been completed. The design challenges, which include switches investigation, switches integration, and service grouping techniques, have been discussed. In the reconfigurable PA portion, a reconfigurable PA structure has first been demonstrated, and includes a reconfigurable output matching network (MN) and a reconfigurable die design. To validate the proposed reconfigurable PA structure, a reconfigurable PA for a 3G cell phone system has been designed with a multi-chip module technique. The reconfigurable PA structure can significantly decrease the real-estate, cost, and complexity of the PA design. Further, by decreasing the number of output ports, the number of poles for the antenna switch will be decreased as well, leading to an insertion loss decrease.