One of the most basic reaction time experiments employed by psychologists is the comparison of latencies to responses for single and redundant targets. The general effect is that participants are capable of responding faster, that is having shorter response latencies when redundant stimuli, as opposed to an individual stimulus, are presented. Interestingly, several models attempting to predict this effect, including the well known race model, have not been entirely successful. The following study evaluated redundancy gain and violations of the race model, in three experimental models: visual only, auditory only, and a visual-auditory bimodal paradigm. The results showed redundancy gain in all three paradigms, but they were only significant violations of the race model for the visual-auditory condition. Additionally, correlations between the different paradigms were explored with respect to redundancy gain and violations of the race model on an individual participant basis.

<p>As a power device material, SiC has gained remarkable attention to its high thermal conductivity and high breakdown electric field. SiC bipolar junction transistors (BJTs) are interesting for applications as power switch for 600 V-1200 V applications. The SiC BJT has potential for very low specific on-resistances and this together with high temperature operation makes it very suitable for applications with high power densities. One disadvantage of the BJT compared with MOSFETs and Insulated Gate Bipolar Transistors (IGBTs) is that the BJT requires a more complex drive circuit with higher power capability. For the SiC BJT to become competitive with field effect transistors, it is important to achieve high current gains to reduce the power required by the drive circuit. Although much progress in SiC BJTs has been made, SiC BJTs still have low common emitter current gain typically in the range 10-50. In this work, a record high current gain exceeding 60 has been demonstrated for a SiC BJT with a breakdown voltage of 1100 V. This result is attributed to an optimized device design, a stable device process and state-of-the-art epitaxial base and emitter layers.</p><p>A new technique to fabricate the extrinsic base using epitaxial regrowth of the extrinsic base layer was proposed. This technique allows fabrication of the highly doped region of the extrinsic base a few hundred nanometers from the intrinsic region. An important factor that made removal of the regrowth difficult was that epitaxial growth of very highly doped layers has a faster lateral than vertical growth rate and the thickness of the p+ layer therefore has a maximum close to the base-emitter sidewall. A remaining p+ regrowth spacer at the edge of the base-emitter junction is proposed to explain the low current gain.</p><p>Under high power operation, the SiC BJTs were strongly influenced by self-heating, which significantly limits the performance of device. The DC I-V characteristics of 4H-SiC BJTs have also been studied in the temperature range 25 °C to 300 °C. The DC current gain at 300 °C decreased 56 % compared to its value at 25 °C. Selfheating effects were quantified by extracting the junction temperature from DC measurements.</p><p>To form good ohmic contacts to both n-type and p-type SiC using the same metal is one important challenge for simplifying SiC Bipolar Junction Transistor (BJT) fabrication. Ohmic contact formation in the SiC BJT process was investigated using sputter deposition of titanium tungsten to both n-type and p-type followed by annealing at 950 oC. The contacts were characterized with linear transmission line method (LTLM) structures. The n+ emitter structure and the p+ base structure contact resistivity after 30 min annealing was 1.4 x 10-4 Ωcm2 and 3.7 x 10-4 Ωcm2, respectively. Results from high-resolution transmission electron microscopy (HRTEM), suggest that diffusion of Si and C atoms into the TiW layer and a reaction at the interface forming (Ti,W)C1-x are key factors for formation of ohmic contacts.</p>

<p>For research purposes Saab has developed a generic mathematical model denoted VEGAS of an aircraft with a configuration similar to JAS 39 Gripen. Today parts of Gripen backup control system are used also for VEGAS making the system subject to both corporate and defense secrecy. </p><p>The main objective of this master thesis is to design, verify and implement public pitch axis flight control system for VEGAS. Furthermore, simplifications regarding the design process is to be examined. </p><p>Design of pitch axis flight control system for the entire flight envelope has been carried out. Linearization of the dynamic model and programming design environment are used as development tools. The control system has been tested and verified in real-time simulator. </p><p>Linear quadratic optimization (LQ) and gain-scheduling are often used when designing aircraft control system. This method tends to require extensive design effort. This thesis suggests an alternative method combining LQ and scaling of parameters.</p>

<p>Robust control design has become a major research area during the last twenty years and there are nowadays several robust design methods available. One example of such a method is the robust loop shaping method that was developed by K. Glover and D. C. MacFarlane in the late 1980s. The idea of this method is to use decentralized controller design to give the singular values of the loop gain a desired shape. This step is called Loop Shaping and it is followed by a Robust Stabilization procedure, which aims to give the closed loop system a maximum degree of stability margins. In this thesis, the robust loop shaping method is used to design a gain scheduled controller for a missile. The report consists of three parts, where the first part introduces the Robust Loop Shaping theory and a Gain Scheduling approach. The second part discusses the missile and its characteristics. In the third part a controller is designed and a short analysis of the closed loop system is performed. A scheduled controller is implemented in a nonlinear environment, in which performance and robustness are tested. Robust Loop Shaping is easy to use and simulations show that the resulting controller is able to cope with model perturbations without considerable loss in performance. The missile should be able to operate in a large speed interval. There, it is shown that a single controller does not stabilize the missile everywhere. The gain scheduled controller is however able to do so, which is shown by means of simulations.</p>

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2009. / Härtill 5 uppsatser.

Diss. (sammanfattning) Skara : Sveriges lantbruksuniv., 2009. / Härtill 4 uppsatser.

CenteringPregnancy is a model of group prenatal care that replaces routine, individual prenatal care. The program brings women together into small groups to receive their care and prenatal education, and is based on three components: risk assessment, education, and support. The model is client-centered, designed to empower pregnant women and support persons, and involves the woman in small group discussions of 8-10 other women of similar gestational age. The group discussions provide support, help women educate each other, and invoke self-monitoring. Currently, there have been few publications that closely examined maternal weight and obesity and associated outcomes in women involved in CenteringPregnancy; and there are a limited number of studies that examined Spanish-speaking CP groups with Latinas. Therefore, the primary purpose of this retrospective cohort study was to compare pregnancy outcomes of Latina women who completed CenteringPregnancy in a public health clinic to women who completed individual care in the same clinic during the same time. The secondary purpose of this study was to understand perceptions of care among multiparous women who recently completed CenteringPregnancy and completed individual prenatal care in the past. Both quantitative and qualitative methods were employed to examine differences in pregnancy outcomes and maternal factors in both prenatal care groups, and to understand women's perceptions and experience in both CenteringPregnancy and individual prenatal care. A total of 487 patient charts were obtained for data collection (Intervention n= 247, Comparison n=240) and 10 women who recently completed CenteringPregnancy at the health department and completed individual prenatal care in the past completed in person in-depth interviews. The results indicated that there were no differences in infant birthweight or gestational age at delivery between the groups. Compared to women in individual care, women in CenteringPregnancy had increased odds of: having a vaginal birth as opposed to a primary cesarean section, aOR =2.57, (95% CI: 1.23-5.36), attending prenatal care visits, aOR=11.03, (95% CI: 4.53, 26.83), attending postpartum care visits, aOR=2.21 (95% CI: 1.20, 4.05) and formula-only feeding their infants, aOR=6.07 (95% CI: 2.57-14.31). Compared to women in individual care, women in CenteringPregnancy had decreased odds of gaining below the recommended amount of gestational weight, aOR=0.41, (95% CI: 0.22, 0.78). Qualitative findings indicated that women who complete CenteringPregnancy were more satisfied with their care, received more education and support and were more empowered to make decisions about their pregnancy and childbirth. The program provides a system of social support that encapsulates all types of social support to provide relief of stress, encourage positive relationships and empower women to help facilitate healthy pregnancies. CenteringPregnancy at the Pinellas County Health Department increased health care utilization and informed and empowered women through social support.

The Adequate Yearly Progress (AYP) Model has been used to make many high-stakes decisions concerning schools, though it does not provide a complete assessment of student academic achievement and school effectiveness. To provide a clearer perspective, many states have implemented various Growth and Value Added Models, in addition to AYP. The purpose of this study was to examine two Value Added Model specifications, the Gain Score Model and the Layered Effects Model, to understand similarities and differences in school effect results. Specifically, this study correlated value added school effect estimates, which were derived from two model specifications and two outcome measures (mathematics and reading test scores). Existing data were obtained from a moderately large and rural school district in Florida. The outcome measures of 7,899 unique students were examined using the Gain Score Model and the Layered Effects Model to estimate school effects. Those school effect estimates were then used to calculate and examine the relationship between school rankings. Overall, the findings in this study indicated that the school effect estimates and school rankings were more sensitive to outcome measures than they were to model specifications. The mathematics and reading correlations from the Gain Score Model for school effects and school rankings were low (indicating high sensitivity), when advancing from Grades 4 to 5, and were moderate in other grades. The mathematics and reading correlations from the Layered Effects Model were low at Grade 5 for school effects and school rankings, as were the correlations at Grade 7 for the school rankings. In the other grades, correlations were moderate to high (indicating lower sensitivity). Correlations between the Gain Score Model and the Layered Effects Model from mathematics were high in each grade for both school effects and school rankings. Reading correlations were also high for each of the grades. These results were similar to the findings of previous school effects research and added to the limited body of literature. Depending upon the outcome measure used, school effects and rankings can vary significantly when using Value Added Models. These models have become a popular component in educational accountability systems, yet there is no one perfect model. If used, these models should be used cautiously, in addition to other accountability approaches.

Addressing the high cost of RF instrumentation has motivated significant research activity, where researchers have proposed various non-standard and alternative test methods of RF circuits to mitigate high test cost. This dissertation describes a test methodology for RF receivers, whereby simple digital circuits comprise the core of the otherwise complex and costly broadband RF/analog signal generation. The proposed test methodology relies on a digital clock, commonly available to RF ICs for the purpose of digital communication, to generate the broadband RF stimulus needed for the receiver analog tests. The test method also utilizes commonly available baseband signal digitization (on-chip or off-chip) to acquire the baseband signal. It then relies on sophisticated, but inexpensive, signal processing to extract and compute standard RF performance parameters, like gain, noise figure (NF), and input-referred third-order intercept point (IIP3). In addition, the test method can extract important baseband (BB) parameters like the BB filter 3 dB bandwidth (BW), filter rejection at specific BB frequencies, or the BB filter profile. The motivation behind the proposed test methodology can be categorized as both architectural and cost reduction-oriented. Architecturally, the proposed test method aims at shifting the complexity involved in the test of RF receivers from the hardware (input) RF signal generation side to the signal processing done on the (output) baseband side. The process of shifting the complexity from the hardware design side to the signal processing side involves significant complex and sophisticated analysis, which is part of this dissertation. Cost-wise, the proposed test methodology enables the use of digital automatic test equipment (ATE) with limited baseband capability, instead of the full standard RF testers. Such a step reduces the initial tester cost and impacts the cost/sec figure spent on test for the life of the ATE tester, thus leading to test cost reduction. / text

Background Excessive gestational weight gain (GWG) poses significant risk for maternal and neonatal health. Various guidelines have recommended healthy diets and enhancing physical activity during pregnancy to prevent excessive GWG. However, results of intervention studies are inconsistent in the developed countries, and there are no official guidelines and few interventions for GWG in China. This paper aims to review and synthesize relevant studies on diet and physical activity interventions to prevent excessive GWG so that practical suggestions can be provided to public health authorities in China. Methods This systematic review was performed using PubMed, Google and Google Scholar to search all relevant studies in English and randomised controlled trials (RCTs) that investigated diet and physical activity interventions to limit excessive GWG up to May 2014. The quality of included studies was assessed using CONSORT statement and JADAD scale. Results Nine studies describing diet and physical activity interventions to prevent excessive GWG were incorporated in the systematic review. Overall, the contents of interventions were diverse, which consisted of one-to-one counselling, and community-based physical activity interventions. Weekly mailed newsletters and supportive telephone calls were used as assistive tools to remind pregnant women of limiting excessive GWG. Seven studies showed less weight gain in pregnant women receiving the intervention, of which four studies demonstrated a reduction in excessive GWG in women with varying body mass index (BMI) spanning the normal, overweight and obese categories, while three studies reported a reduction of excessive GWG only in normal weight women and obese women need to be paid attention in the future. Conclusions The effectiveness of diet and physical interventions to limit excessive GWG may not be confirmed because of limited quality or sample size of intervention studies. However, studies have demonstrated reduction of excessive GWG during pregnancy, in addition to persistent healthy behaviours following such interventions during pregnancy. Further meta-analyses of RCTs studies should be done to confirm the effectiveness of such interventions among Chinese women. / published_or_final_version / Public Health / Master / Master of Public Health