Parameter optimization for noise and vibration reduction associated with position and speed sensorless control of permanent magnet machines at low speed

With the advantages and popularity of Permanent Magnet (PM) motors due to their high power density, there is an increasing incentive to use them in variety of applications including electric actuation. These applications have strict noise emission standards. The generation of audible noise and associated vibration modes are characteristics of all electric motors, it is especially problematic in low speed sensorless control rotary actuation applications using high frequency voltage injection technique. This dissertation is aimed at solving the problem of optimizing the sensorless control algorithm for low noise and vibration while achieving at least 12 bit absolute accuracy for speed and position control. The low speed sensorless algorithm is simulated using an improved Phase Variable Model, developed and implemented in a hardware-in-the-loop prototyping environment. Two experimental testbeds were developed and built to test and verify the algorithm in real time.^ A neural network based modeling approach was used to predict the audible noise due to the high frequency injected carrier signal. This model was created based on noise measurements in an especially built chamber. The developed noise model is then integrated into the high frequency based sensorless control scheme so that appropriate tradeoffs and mitigation techniques can be devised. This will improve the position estimation and control performance while keeping the noise below a certain level. Genetic algorithms were used for including the noise optimization parameters into the developed control algorithm.^ A novel wavelet based filtering approach was proposed in this dissertation for the sensorless control algorithm at low speed. This novel filter was capable of extracting the position information at low values of injection voltage where conventional filters fail. This filtering approach can be used in practice to reduce the injected voltage in sensorless control algorithm resulting in significant reduction of noise and vibration.^ Online optimization of sensorless position estimation algorithm was performed to reduce vibration and to improve the position estimation performance. The results obtained are important and represent original contributions that can be helpful in choosing optimal parameters for sensorless control algorithm in many practical applications.^

Impact of a cognitive-behavioral weight control program on body weight, diet quality, and smoking cessation in weight-concerned female smokers

Many people use smoking as a weight control mechanism and do not want to quit because they fear weight gain. These weight-concerned smokers tend to be female, are significantly less likely to stop smoking, are less likely to join smoking cessation programs, and will relapse more often than smokers who are not weight-concerned. Research suggests that a woman’s confidence in her ability to control her weight after quitting relates positively with her intention to quit smoking. Likewise, success in smoking cessation has been associated with increased self-efficacy for weight control. It has been shown that success in changing one negative health behavior may trigger success in changing another, causing a synergistic effect. Recently research has focused on interventions for weight-concerned smokers who are ready to quit smoking. The present study investigated the effect of a cognitive based weight control program on self-efficacy for weight control and the effect on smoking behavior for a group of female weight concerned smokers. Two hundred and sixteen subjects who wanted to lose weight but who were not ready to quit smoking were recruited to participate in a 12-week, cognitive-behavioral weight control program consisting of twelve one-hour sessions. Subjects were randomly assigned to either (1) the weight-control program (intervention group), or (2) the control group. Results of this study demonstrated that subjects in the intervention group increased self-efficacy for weight control, which was associated with improved healthy eating index scores, weight loss, increased self-efficacy for quitting smoking, a decrease in number of cigarettes smoked and triggered positive movement in stage of change towards smoking cessation compared to the control subjects. For these subjects, positive changes in self-efficacy for one behavior (weight control) appeared to have a positive effect on their readiness to change another health behavior (smoking cessation). Further study of the psychological variables that influence weight-concerned female smokers’ decisions to initiate changes in these behaviors and their ability to maintain those changes are warranted.

Factors surgical team members perceive influence choices of wearing or not wearing personal protective equipment during operative /invasive procedures

Exposure to certain bloodborne pathogens can prematurely end a person’s life. Healthcare workers (HCWs), especially those who are members of surgical teams, are at increased risk of exposure to these pathogens. The proper use of personal protective equipment (PPE) during operative/invasive procedures reduces that risk. Despite this, some HCWs fail to consistently use PPE as required by federal regulation, accrediting agencies, hospital policy, and professional association standards. The purpose of this mixed methods survey study was to (a) examine factors surgical team members perceive influence choices of wearing or not wearing PPE during operative/invasive procedures and (b) determine what would influence consistent use of PPE by surgical team members. Using an ex post facto, non-experimental design, the memberships of five professional associations whose members comprise surgical teams were invited to complete a mixed methods survey study. The primary research question for the study was: What differences (perceptual and demographic) exist between surgical team members that influence their choices of wearing or not wearing PPE during operative/invasive procedures? Four principal differences were found between surgical team members. Functional (i.e., profession or role based) differences exist between the groups. Age and experience (i.e., time in profession) differences exist among members of the groups. Finally, being a nurse anesthetist influences the use of risk assessment to determine the level of PPE to use. Four common themes emerged across all groups informing the two study purposes. Those themes were: availability, education, leadership, and performance. Subsidiary research questions examined the influence of previous accidental exposure to blood or body fluids, federal regulations, hospital policy and procedure, leaders’ attitudes, and patients’ needs on the use of PPE. Each of these was found to strongly influence surgical team members and their use of PPE during operative/invasive procedures. Implications based on the findings affect organizational policy, purchasing and distribution decisions, curriculum design and instruction, leader behavior, and finally partnership with PPE manufacturers. Surgical team members must balance their innate need to care for patients with their need to protect themselves. Results of this study will help team members, leaders, and educators achieve this balance.

Two-bit pattern analysis for quantitative information flow

Protecting confidential information from improper disclosure is a fundamental security goal. While encryption and access control are important tools for ensuring confidentiality, they cannot prevent an authorized system from leaking confidential information to its publicly observable outputs, whether inadvertently or maliciously. Hence, secure information flow aims to provide end-to-end control of information flow. Unfortunately, the traditionally-adopted policy of noninterference, which forbids all improper leakage, is often too restrictive. Theories of quantitative information flow address this issue by quantifying the amount of confidential information leaked by a system, with the goal of showing that it is intuitively "small" enough to be tolerated. Given such a theory, it is crucial to develop automated techniques for calculating the leakage in a system. ^ This dissertation is concerned with program analysis for calculating the maximum leakage, or capacity, of confidential information in the context of deterministic systems and under three proposed entropy measures of information leakage: Shannon entropy leakage, min-entropy leakage, and g-leakage. In this context, it turns out that calculating the maximum leakage of a program reduces to counting the number of possible outputs that it can produce. ^ The new approach introduced in this dissertation is to determine two-bit patterns, the relationships among pairs of bits in the output; for instance we might determine that two bits must be unequal. By counting the number of solutions to the two-bit patterns, we obtain an upper bound on the number of possible outputs. Hence, the maximum leakage can be bounded. We first describe a straightforward computation of the two-bit patterns using an automated prover. We then show a more efficient implementation that uses an implication graph to represent the two- bit patterns. It efficiently constructs the graph through the use of an automated prover, random executions, STP counterexamples, and deductive closure. The effectiveness of our techniques, both in terms of efficiency and accuracy, is shown through a number of case studies found in recent literature. ^

Factors Surgical Team Members Perceive Influence Choices of Wearing or not Wearing Personal Protective Equipment During Operative/Invasive Procedures

Exposure to certain bloodborne pathogens can prematurely end a person’s life. Healthcare workers (HCWs), especially those who are members of surgical teams, are at increased risk of exposure to these pathogens. The proper use of personal protective equipment (PPE) during operative/invasive procedures reduces that risk. Despite this, some HCWs fail to consistently use PPE as required by federal regulation, accrediting agencies, hospital policy, and professional association standards. The purpose of this mixed methods survey study was to (a) examine factors surgical team members perceive influence choices of wearing or not wearing PPE during operative/invasive procedures and (b) determine what would influence consistent use of PPE by surgical team members. Using an ex post facto, non-experimental design, the memberships of five professional associations whose members comprise surgical teams were invited to complete a mixed methods survey study. The primary research question for the study was: What differences (perceptual and demographic) exist between surgical team members that influence their choices of wearing or not wearing PPE during operative/invasive procedures? Four principal differences were found between surgical team members. Functional (i.e., profession or role based) differences exist between the groups. Age and experience (i.e., time in profession) differences exist among members of the groups. Finally, being a nurse anesthetist influences the use of risk assessment to determine the level of PPE to use. Four common themes emerged across all groups informing the two study purposes. Those themes were: availability, education, leadership, and performance. Subsidiary research questions examined the influence of previous accidental exposure to blood or body fluids, federal regulations, hospital policy and procedure, leaders’ attitudes, and patients’ needs on the use of PPE. Each of these was found to strongly influence surgical team members and their use of PPE during operative/invasive procedures. Implications based on the findings affect organizational policy, purchasing and distribution decisions, curriculum design and instruction, leader behavior, and finally partnership with PPE manufacturers. Surgical team members must balance their innate need to care for patients with their need to protect themselves. Results of this study will help team members, leaders, and educators achieve this balance.