This thesis is concerned with robust control of an offshore steel jacket platform subject to nonlinear wave-induced forces. Since time delay and uncertainty are inevitably encountered for an offshore structure and their existence may induce instability, oscillation and poor performance, it is very significant to study on how the delay and uncertainty affect the offshore structure. In this thesis, a memory robust control strategy is, for the first time, proposed to reduce the internal oscillations of the offshore structure under wave-induced forces, so as to ensure the safety and comfort of the offshore structure. Firstly, when the system's states are adopted as feedback, memory state feedback controllers are introduced for the offshore structure. By using Lyapunov-Krasovskii stability theory, some delay-dependent stability criteria have been established, based on which, and by combining with some linearization techniques, memory state feedback controllers are designed to control the offshore structure. The simulation results show that such controllers can effectively reduce the internal oscillations of the offshore structure subject to nonlinear wave-induced forces and uncertainties. On the other hand, a new Lyapunov-Krasovskii functional is introduced to derive a less conservative delay-dependent stability criterion. When this criterion is applied to the offshore structure, an improved memory state feedback controller with a small gain is obtained to control the system more effectively, which is sufficiently shown by the simulation. Secondly, when the system's outputs are adopted as feedback, memory dynamic output feedback controllers are considered for the offshore structure. By employing a projection theorem and a cone complementary linearization approach, memory dynamic output feedback controllers are derived by solving some nonlinear minimization problem subject to some linear matrix inequalities. The simulation results show that the internal oscillations of the offshore structure subject to nonlinear wave-induced forces are well attenuated. Finally, robust H control is fully investigated for the offshore structure. By employing Lyapunov-Krasovskii stability theory, some delay-dependent bounded real lemmas have been obtained, under which, via a memory state feedback controller or a dynamic output feedback controller, the resulting closed-loop system is not only asymptotically stable but also with a prescribed disturbance attenuation level. The simulation results illustrate the validity of the proposed method.

<p>To save time in Flextronics high volume production, the time for test and calibration of mobile telephones need to be as short and accurate as possible. In the wideband code division multiple access (WCDMA) case, the output power calibration is the most critical calibration concerning accuracy. The aim with this thesis was to find a faster calibration method than the one that exists today and still retain accuracy. </p><p>The Third Generation Partnership Project (3GPP) outlines the requirements of the output power and they must be thoroughly considered when choosing calibration method. Measurement accuracy and the behavior of the transmitter chain parameters also must be considered. </p><p>The output power in the WCDMA phone studied is controlled by seven parameters. The parameters are characterized in this thesis, and are found to be too hardware dependent to be predicted or to be seen as predictions from each other. </p><p>Since no parameter predictions are possible it was stated that all parameters have to be measured, and a new way of measuring them in a faster way is proposed. The principle of the new measurement method is presented, and the implemented software is tested and evaluated. The new method mainly makes use of the spectrum analyzer zero span function. </p><p>The evaluation shows that the new method is faster than the original and retains accuracy. The measurement uncertainties even seem to diminish, which implicates decreased temperature dependence due to faster measurement time.</p>

No description available.

We present a method for Poisson’s equation that computes guaranteed upper and lower bounds for the values of linear functional outputs of the exact weak solution of the infinite dimensional continuum problem using traditional finite element approximations. The guarantee holds uniformly for any level of refinement, not just in the asymptotic limit of refinement. Given a finite element solution and its output adjoint solution, the method can be used to provide a certificate of precision for the output with an asymptotic complexity which is linear in the number of elements in the finite element discretization. / Singapore-MIT Alliance (SMA)

We introduce a new method for computing a posteriori bounds on engineering outputs from finite element discretizations of the incompressible Stokes equations. The method results from recasting the output problem as a minimization statement without resorting to an error formulation. The minimization statement engenders a duality relationship which we solve approximately by Lagrangian relaxation. We demonstrate the method for a stabilized equal-order approximation of Stokes flow, a problem to which previous output bounding methods do not apply. The conceptual framework for the method is quite general and shows promise for application to stabilized nonlinear problems, such as Burger's equation and the incompressible Navier-Stokes equations, as well as potential for compressible flow problems. / Singapore-MIT Alliance (SMA)

We present a technique for the rapid and reliable prediction of linear-functional outputs of elliptic (and parabolic) partial differential equations with affine parameter dependence. The essential components are (i) (provably) rapidly convergent global reduced-basis approximations -- Galerkin projection onto a space WN spanned by solutions of the governing partial differential equation at N selected points in parameter space; (ii) a posteriori error estimation -- relaxations of the error-residual equation that provide inexpensive yet sharp and rigorous bounds for the error in the outputs of interest; and (iii) off-line/on-line computational procedures -- methods which decouple the generation and projection stages of the approximation process. The operation count for the on-line stage -- in which, given a new parameter value, we calculate the output of interest and associated error bound -- depends only on N (typically very small) and the parametric complexity of the problem; the method is thus ideally suited for the repeated and rapid evaluations required in the context of parameter estimation, design, optimization, and real-time control. / Singapore-MIT Alliance (SMA)

by H.P. Stabler. / "March 3, 1947." / Includes bibliographical references. / Army Signal Corps Contract No. W-36-039 sc-32037.

<p>Abstract 1.</p><p>The purpose of this study was to investigate the effects whole body vibrations on maximal strength, power output and neuromuscular activity in m. pectoralis major during bench press.</p><p>Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks</p><p> </p><p>Initial load at 60 % of 1 RM showed an average of 46, 5 kg. All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. </p><p>All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training.</p><p>Abstract 2. </p><p>The purpose of this study was to investigate the effects whole body vibrations on strength development, power output and neuromuscular activity in m. pectoralis major during bench press. The purpose was also to examine what roll self-efficacy plays in strength tasks. </p><p>Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks. All participants answered a battery of questionnaires concerning backgrounds, motives for sport participation, self-efficacy and efficacy sources. </p><p>Initial load at 60 % of 1 RM showed an average of 46, 5 kg (sd = 13, 8). All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. Gender differences showed that men lifted significantly heavier loads at 60 % of 1RM compared to women. </p><p>No significant differences could be seen between the groups concerning self efficacy. Gender differences were exposed concerning self-efficacy to push ups with a pat. The efficacy sources “performance accomplishments” was valuated to be the most influential to form self-efficacy expectations. A strong positive relationship between “performance accomplishments” and achieved self-efficacy to push ups with pats were shown. Self-efficacy to push ups with a pat also correlated positively with power output and performed 60 % of 1 RM in bench press. </p><p>All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training. Participants relatively high self-efficacy to strength tasks is probably a result of performance accomplishments in there own strength straining rather than the intervention training. Positive relationships between self-efficacy and power output as well as performed 60 % of 1 RM in bench press, indicating that high self-efficacy have a positive influence on strength performance. </p><p>Keywords: estimated maximal strength (1RM), neuromuscular activity, power output, self-efficacy.</p>

Human anaphylatoxin C3a increases glycogenolysis in perfused rat liver. This action is inhibited by prostanoid synthesis inhibitors and prostanoid antagonists. Because prostanoids but not anaphylatoxin C3a can increase glycogenolysis in hepatocytes, it has been proposed that prostanoid formation in nonparenchymal cells represents an important step in the C3a-dependent increase in hepatic glycogenolysis. This study shows that (a) human anaphylatoxin C3a (0.1 to 10 mug/ml) dose-dependently increased prostaglandin D2, thromboxane B, and prostaglandin F2alpha formation in rat liver macrophages (Kupffer cells); (b) the C3a-mediated increase in prostanoid formation was maximal after 2 min and showed tachyphylaxis; and (c) the C3a-elicited prostanoid formation could be inhibited specifically by preincubation of C3a with carboxypeptidase B to remove the essential C-terminal arginine or by preincubation of C3a with Fab fragments of a neutralizing monoclonal antibody. These data support the hypothesis that the C3a-dependent activation of hepatic glycogenolysis is mediated by way of a C3a-induced prostanoid production in Kupffer cells.

Abstract 1. The purpose of this study was to investigate the effects whole body vibrations on maximal strength, power output and neuromuscular activity in m. pectoralis major during bench press. Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks Initial load at 60 % of 1 RM showed an average of 46, 5 kg. All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training. Abstract 2. The purpose of this study was to investigate the effects whole body vibrations on strength development, power output and neuromuscular activity in m. pectoralis major during bench press. The purpose was also to examine what roll self-efficacy plays in strength tasks. Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks. All participants answered a battery of questionnaires concerning backgrounds, motives for sport participation, self-efficacy and efficacy sources. Initial load at 60 % of 1 RM showed an average of 46, 5 kg (sd = 13, 8). All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. Gender differences showed that men lifted significantly heavier loads at 60 % of 1RM compared to women. No significant differences could be seen between the groups concerning self efficacy. Gender differences were exposed concerning self-efficacy to push ups with a pat. The efficacy sources “performance accomplishments” was valuated to be the most influential to form self-efficacy expectations. A strong positive relationship between “performance accomplishments” and achieved self-efficacy to push ups with pats were shown. Self-efficacy to push ups with a pat also correlated positively with power output and performed 60 % of 1 RM in bench press. All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training. Participants relatively high self-efficacy to strength tasks is probably a result of performance accomplishments in there own strength straining rather than the intervention training. Positive relationships between self-efficacy and power output as well as performed 60 % of 1 RM in bench press, indicating that high self-efficacy have a positive influence on strength performance. Keywords: estimated maximal strength (1RM), neuromuscular activity, power output, self-efficacy.