Det här examensarbetet presenterar en evaluering av en Klockkorrigerare av klockpulsbredd. Den består främst av en korrigerare av klockpulsbredd (Duty Cycle Corrector DCC) och även en fördröjningslåst loop (Delayed Locked Loop DLL). Det finns många olika korrigerare av klockpulsbredden designade förut, de två populäraste arkitekturerna då har varit enkel eller dubbel återkopplings loop. Den huvudsakliga skillnaden mellan dem är att enkel återkopplings loop använder sig av en öppen loop medan den dubbla varianten istället har en stängd loop. I det här projektet kommer en ny arkitektur att presenteras. Konceptet i den nya designen är att dela upp korrigeraren av klockpulsbredden i två delar, en korrigerare och en detektor. Detektorn får utsignalen från den fördröjningslåsta loopen som insignal och talar om för korrigeraren via två utsignaler ifall signalen behöver justeras. Detektorn är uppdelad i två likadana fördröjningselement, som båda är klockade av utsignalen och dess invers från den fördröjningslåsande loopen, fast i omvänd ordning. Det här gör det möjligt att avgöra om klockpulsbredden av signalen är över eller under 50 %. Om så är fallet kommer den att justeras av korrigeraren för att sedan skickas som insignal till den fördröjningslåsande loopen. Abstraktionsnivån för det här projektet har varit systemnivå, detta för att kunna vara riktigt säker på att arkitekturen verkligen fungerar innan ett riktigt chip tillverkas. Tips på framtida projekt är att gå vidare till schemanivå för att slutligen göra en implementering och mätningar på ett riktigt chip av den här Klockkorrigeraren av klockpulsbredd när det är känt att idén fungerar.

The demand for wireless data services has been dramatically growing over the last decade. This growth has been accompanied by a significant increase in the number of users sharing the same wireless medium, and as a result, interference management has become a hot topic of research in recent years. In this dissertation, we investigate feedback and transmitter cooperation as two closely related tools to manage the interference and achieve high data rates in several wireless networks, focusing on additive white Gaussian noise (AWGN) interference, X, and broadcast channels. We start by a one-to-many network, namely, the three-user multiple-input multiple-output (MIMO) Gaussian broadcast channel, where we assume that the transmitter obtains the channel state information (CSI) through feedback links after a finite delay. We also assume that the feedback delay is greater than the channel coherence time, and thus, the CSI expires prior to being exploited by the transmitter for its current transmission. Nevertheless, we show that this delayed CSI at the transmitter (delayed CSIT) can help the transmitter to achieve significantly higher data rates compared to having no CSI. We indeed show that delayed CSIT increases the channel degrees of freedom (DoF), which is translated to an unbounded increase in capacity with increasing signal-to-noise-ratio (SNR). For the symmetric case, i.e. with the same number of antennas at each receiver, we propose different transmission schemes whose achievable DoFs meet the upper bound for a wide range of transmit-receive antenna ratios. Also, for the general non-symmetric case, we propose transmission schemes that characterize the DoF region for certain classes of antenna configurations. Subsequently, we investigate channels with distributed transmitters, namely, Gaussian single-input single-output (SISO) K-user interference channel and 2×K X channel under the delayed CSIT assumption. In these channels, in major contrast to the broadcast channel, each transmitter has access only to its own messages. We propose novel multiphase transmission schemes wherein the transmitters collaboratively align the past interference at appropriate receivers using the knowledge of past CSI. Our achievable DoFs are greater than one (which is the channel DoF without CSIT), and strictly increasing in K. Our results are yet the best available reported DoFs for these channels with delayed CSIT. Furthermore, we consider the K-user r-cyclic interference channel, where each transmitter causes interference on only r receivers in a cyclic manner. By developing a new upper bound, we show that this channel has K/r DoF with no CSIT. Moreover, by generalizing our multiphase transmission ideas, we show that, for r=3, this channel can achieve strictly greater than K/3 DoF with delayed CSIT. Next, we add the capability of simultaneous transmission and reception, i.e. full-duplex operation, to the transmitters, and investigate its impact on the DoF of the SISO Gaussian K-user interference and M×K X channel under the delayed CSIT assumption. By proposing new cooperation/alignment techniques, we show that the full-duplex transmitter cooperation can potentially yield DoF gains in both channels with delayed CSIT. This is in sharp contrast to the previous results on these channels indicating the inability of full-duplex transmitter cooperation to increase the channel DoF with either perfect instantaneous CSIT or no CSIT. With the recent technological advances in implementation of full-duplex communication, it is expected to play a crucial role in the future wireless systems. Finally, we consider the Gaussian K-user interference and K×K X channel with output feedback, wherein each transmitter causally accesses the output of its paired receiver. First, using the output feedback and under no CSIT assumption, we show that both channels can achieve DoF values greater than one, strictly increasing in K, and approaching the limiting value of 2 as K→∞. Then, we develop transmission schemes for the same channels with both output feedback and delayed CSIT, known as Shannon feedback. Our achievable DoFs with Shannon feedback are greater than those with the output feedback for almost all values of K.

Judgments of Learning (JOL) that are made after a delay, instead of immediately after study, are more accurate in terms of predicting later recall (the delayed JOL effect). The Self-Fulfilling Prophecy (SFP) theory explains the delayed JOL effect as the result of a testing effect. In the current study we tested the prediction that performing delayed JOLs leads to a memory improvement. During learning, 79 participants studied Swahili-Swedish word pairs, immediately followed by a cued recall test, and then made either one single or three repeated, spaced JOLs. A final cued recall test was given after either 5 minutes or 1 week. Making repeated JOLs did not increase memory performance compared to the single JOL condition, hence lending no support to the SFP theory. However, making repeated JOLs did improve their relative accuracy, which suggests that the delayed JOL effect mainly concerns memory monitoring and not performance.

Cantilevered reinforced concrete columns with a lap splice of the longitudinal reinforcement near the base can induce high moment demands on the splice region when lateral loads are present on the structure. Code design specifications typically require a conservative splice length to account for these high moment demands and their consequences of bond failure. The required splice length is calculated as a function of required development length, which is a function of the bond between the reinforcement and the surrounding concrete, and a factor depending on the section detailing. However, the effects of concrete deterioration due to alkali silica reaction (ASR) and/or delayed ettringite formation (DEF) may weaken the bond of the splice region enough to overcome the conservative splice length, potentially resulting in brittle failure of the column during lateral loading. This thesis presents the following results obtained from an experimental and analytical program. * Fabrication of large-scale specimens of typical column splice regions with concrete that is susceptible to ASR/DEF deterioration * Measurement of the large-scale specimen deterioration due to ASR/DEF accelerated deterioration * Analytical model of the column splice region based on flexure theory as a function of the development length of the reinforcement and a factor to account for deterioration of the bond due to ASR/DEF * Experimental behavior of two large-scale specimens that are not influenced by premature concrete deterioration due to ASR/DEF (control specimens). This experimental data is also used to calibrate the analytical model. The conclusions of the research are that the analytical model correlates well with the experimental behavior of the large-scale control specimens not influenced by ASR/DEF. The lap splice region behaved as expected and an over-strength in the splice region is evident. To account for ASR/DEF damage, the analytical model proposes a reduction factor to decrease the bond strength of the splice region to predict ultimate performance of the region with different levels of premature concrete deterioration.

Reinforced concrete bridge columns can deteriorate prematurely due to the alkali-silica reaction (ASR) and/or delayed ettringite formation (DEF), causing internal expansion and cracking on the surface of the concrete. The performance of the longitudinal reinforcement lap splice in deteriorated concrete columns is the focus in this research. This thesis presents the results from the deterioration of large-scale specimens constructed and placed in an environment susceptible to ASR/DEF deterioration, the experimental results from four-point and three-point structural load tests, and an analytical model based on bending theory characterizing the specimen behavior during the structural load tests. Fourteen large-scale specimens were constructed, placed in an environment to accelerate the ASR/DEF deterioration mechanisms, and instrumented both internally and externally to measure the internal concrete expansions, and surface expansions and crack widths. In addition, two control specimens were constructed and kept in a laboratory, preventing ASR/DEF deterioration. Post-tensioning was used to simulate axial load on a bridge column. Structural load tests were performed on eight specimens with no ASR/DEF damage to late stage ASR and minimal DEF damage. Comparing the specimen behaviors during the loading testing, it was found that the yield strength increased about 5-15%, and post-cracking stiffness up to first yielding of the deteriorated specimens was about 25-35% stiffer than the control specimens. The increased specimen strength and stiffness likely occurred from volumetric expansion due to ASR/DEF damage which engaged the reinforcement, further confining the concrete and causing a beneficial increase in the axial post-tensioning load. The analytical model matched the control specimens well and matched the non-control specimens when the axial load was increased.

Oscillations are present at many different levels of biological organization. The cell cycle that directs the division of individual cells, the regular depolarization of neurons in the sinu-atrial node which underlies the regular beating of the heart, the circadian rhythms that govern the daily activity cycles of virtually all organisms, and the clocks that make entire populations of fireflies flash on and off in unison feature as prominent examples of biological clocks. During development, biological clocks regulate the patterning of growing tissues, as is the case in vertebrate somitogenesis, and potentially also in vertebrate limb outgrowth and axial segmentation of invertebrate embryos. During vertebrate segmentation, the embryonic axis is subdivided along its anterior-posterior axis into epithelial spheres of cells called somites. This rhythmic process is thought to be driven by a multicellular oscillatory gene network, the so-called segmentation clock. Oscillations of hairy and enhancer of split gene products have been proposed to constitute the core clockwork in individual cells, and these oscillators are coupled to each other by Delta-Notch intercellular signaling. The interaction of the segmentation clock with a posteriorly-moving arrest wavefront then translates the temporal information encoded by the clock into a spatial pattern of segments. In the framework of this Clock and Wavefront model, segment length is determined by both clock period and arrest wavefront velocity. How the period of the segmentation clock is regulated is presently unknown, and understanding the mechanism of period setting might yield insight into the nature and function of the segmentation clock. In this study, two different but complementary approaches were pursued to investigate how period is regulated in the zebrafish segmentation clock. First, it has been reported that zebrafish mind bomb (mib) mutant embryos form somites more slowly than their wt siblings, suggesting that Mib might be implicated in period setting. Mib is an E3 ubiquitin ligase required for ubiquitination and endocytosis of the Notch ligand Delta, and Notch signaling is impaired in mutants with defective Mib. It has been suggested that the mechanistic basis for the requirement of Delta endocytosis in Notch signaling is a need for Delta to enter a particular endocytic compartment, potentially a recycling endosome, in a ubiquitin-dependent manner, where its signaling ability might be established or amplified by an as yet unknown posttranslational modification. In the present study, Delta trafficking through the endocytic pathway was analyzed in the PSM of wt and mib embryos through colocalization studies with endocytic markers. The rationale of this approach was that if Delta gained access to a particular endocytic compartment through Mib-dependent endocytosis, the presence of Delta in this compartment would be expected to be reduced in mutants with defective Mib, thereby revealing the compartment’s identity. However, no qualitative changes in colocalization with different endocytic markers could be detected in mib mutants, and the methods available did not allow for quantification of colocalization in wt or mutant backgrounds. However, Delta colocalized with 13 markers of recycling endosomes, consistent with the hypothesis that these are functionally important in Notch signaling. More refined techniques will be necessary for a quantitative analysis of normal as compared to impaired Delta trafficking. A genetic approach to period regulation proved to be successful for the Drosophila circadian clock, where the identification of period mutants advanced the understanding of the clock’s genetic circuitry. This motivated a screen for period mutants of the segmentation clock, which was carried out by measuring somitogenesis period, segment length and arrest wavefront velocity in a pool of candidate mutants. A subset of Delta-Notch mutants, and embryos treated with a small-molecule inhibitor that impairs Notch signaling, displayed correlated increases in somitogenesis period and segment length, while there was no detectable change in arrest wavefront velocity. Combined, these findings suggested that segmentation clock period is increased in experimental conditions with impaired Delta-Notch signaling. Using a theoretical description of the segmentation clock as an array of coupled phase oscillators, the delay in the coupling and the autonomous frequency of individual cells were estimated from the direction and magnitude of the period changes. The mutants presented here are the first candidates for segmentation clock period mutants in any vertebrate. The nature of the molecular lesions in these mutants, all of which affect genes implicated in intercellular Delta-Notch signaling, suggests that communication between oscillating PSM cells is a key factor responsible for setting the period of the segmentation clock.

<p>Simultaneous Localisation And Mapping SLAM-problemet är ett robotikproblem som består av att låta en robot kartlägga ett tidigare okänt område, och samtidigt lokalisera sig i den skapade kartan. Det här exjobbet presenterar ett försök till en lösning på SLAM-problemet som fungerar i konstant tid i en urban miljö. En sådan lösning måste hantera en datamängd som ständigt ökar, utan att beräkningskomplexiteten ökar signifikant.</p><p>Ett informationsfilter på fördröjd tillståndsform används för estimering av robotens trajektoria, och kamera och laseravståndssensorer används för att samla spatial information om omgivningarna längs färdvägen. Två olika metoder för att detektera loopslutningar föreslås. Den första är bildbaserad och använder Tree of Words för jämförelse av bilder. Den andra metoden är laserbaserad och använder en tränad klassificerare för att jämföra laserscans. När två posar, position och riktning, kopplats samman i en loopslutning beräknas den relativa posen med laserscansinriktning med hjälp av en kombination av Conditional Random Field-Match och Iterative Closest Point.</p><p>Experiment visar att både bild- och laserscansbaserad loopslutningsdetektion fungerar bra i stadsmiljö, och resulterar i good estimering av kartan såväl som robotens trajektoria.</p> / <p>In robotics, the Simultaneous Localisation And Mapping SLAM problem consists of letting a robot map a previously unknown environment, while simultaneously localising the robot in the same map. In this thesis, an attempt to solve the SLAM problem in constant time in a complex environment, such as a suburban area, is made. Such a solution must handle increasing amounts of data without significant increase in computation time.</p><p>A delayed state information filter is used to estimate the robot's trajectory, and camera and laser range sensors are used to acquire spatial information about the environment along the trajectory. Two approaches to loop closure detection are proposed. The first is image based using Tree of Words for image comparison. The second is laser based using a trained classifier for laser scan comparison. The relative pose, the difference in position and heading, of two poses matched in loop closure is calculated with laser scan alignment using a combination of Conditional Random Field-Match and Iterative Closest Point.</p><p>Experiments show that both image and laser based loop closure detection works well in a suburban area, and results in good estimation of the map as well as the robot's trajectory.</p>

In the last decade or so, there has been a dramatic increase in storage facilities and the possibility of processing huge amounts of data. This has made large high-quality data sets widely accessible for practitioners. This technology innovation seriously challenges traditional modeling and inference methodology. This thesis is devoted to developing inference and modeling tools to handle large data sets. Four included papers treat various important aspects of this topic, with a special emphasis on Bayesian inference by scalable Markov Chain Monte Carlo (MCMC) methods. In the first paper, we propose a novel mixture-of-experts model for longitudinal data. The model and inference methodology allows for manageable computations with a large number of subjects. The model dramatically improves the out-of-sample predictive density forecasts compared to existing models. The second paper aims at developing a scalable MCMC algorithm. Ideas from the survey sampling literature are used to estimate the likelihood on a random subset of data. The likelihood estimate is used within the pseudomarginal MCMC framework and we develop a theoretical framework for such algorithms based on subsets of the data. The third paper further develops the ideas introduced in the second paper. We introduce the difference estimator in this framework and modify the methods for estimating the likelihood on a random subset of data. This results in scalable inference for a wider class of models. Finally, the fourth paper brings the survey sampling tools for estimating the likelihood developed in the thesis into the delayed acceptance MCMC framework. We compare to an existing approach in the literature and document promising results for our algorithm. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 2: Submitted. Paper 3: Manuscript. Paper 4: Manuscript.</p>

Simultaneous Localisation And Mapping SLAM-problemet är ett robotikproblem som består av att låta en robot kartlägga ett tidigare okänt område, och samtidigt lokalisera sig i den skapade kartan. Det här exjobbet presenterar ett försök till en lösning på SLAM-problemet som fungerar i konstant tid i en urban miljö. En sådan lösning måste hantera en datamängd som ständigt ökar, utan att beräkningskomplexiteten ökar signifikant. Ett informationsfilter på fördröjd tillståndsform används för estimering av robotens trajektoria, och kamera och laseravståndssensorer används för att samla spatial information om omgivningarna längs färdvägen. Två olika metoder för att detektera loopslutningar föreslås. Den första är bildbaserad och använder Tree of Words för jämförelse av bilder. Den andra metoden är laserbaserad och använder en tränad klassificerare för att jämföra laserscans. När två posar, position och riktning, kopplats samman i en loopslutning beräknas den relativa posen med laserscansinriktning med hjälp av en kombination av Conditional Random Field-Match och Iterative Closest Point. Experiment visar att både bild- och laserscansbaserad loopslutningsdetektion fungerar bra i stadsmiljö, och resulterar i good estimering av kartan såväl som robotens trajektoria. / In robotics, the Simultaneous Localisation And Mapping SLAM problem consists of letting a robot map a previously unknown environment, while simultaneously localising the robot in the same map. In this thesis, an attempt to solve the SLAM problem in constant time in a complex environment, such as a suburban area, is made. Such a solution must handle increasing amounts of data without significant increase in computation time. A delayed state information filter is used to estimate the robot's trajectory, and camera and laser range sensors are used to acquire spatial information about the environment along the trajectory. Two approaches to loop closure detection are proposed. The first is image based using Tree of Words for image comparison. The second is laser based using a trained classifier for laser scan comparison. The relative pose, the difference in position and heading, of two poses matched in loop closure is calculated with laser scan alignment using a combination of Conditional Random Field-Match and Iterative Closest Point. Experiments show that both image and laser based loop closure detection works well in a suburban area, and results in good estimation of the map as well as the robot's trajectory.

Background: The causes of childhood brain tumors (CBT) are essentially unknown. Exposure to extremely low frequency magnetic fields (ELF-MF) (3-3000Hz) is an ubiquitous part of modern life. However, very few studies have investigated the possible effect of maternal occupational ELF-MF exposure on CBT and the available findings are inconsistent across studies. / Methods: We examined the role of maternal occupational exposure to ELF-MF shortly before and during pregnancy on the incidence of childhood brain tumors. A total of 548 incident cases and 760 healthy controls recruited between 1980 and 2002 from two Canadian provinces (Quebec and Ontario) were included and their mothers were interviewed. Tumors were classified as astroglial tumors, primitive neuroectodermal tumors (PNET), and other gliomas. Quantitative occupational ELF-MF exposure in microtesla units was estimated using individual exposure estimations or a job exposure matrix. We used three metrics to analyze exposure: cumulative, average, and maximum level attained. / Results: Using the average exposure metric measured before conception, an increased risk was observed for astroglial tumors (OR=1.5, and 95% CI=1.0-2.4). During the entire pregnancy period, a significantly increased risk was observed for astroglial tumors as well as for all childhood brain tumors with the average metric (OR=1.6, 95% CI=1.1-2.5 and OR=1.5; 95% CI=1.1-2.2, respectively). Based on job titles, a two-fold risk increase was observed for astroglial tumors (OR=2.3, 95% CI=0.8-6.3) and for all childhood brain tumors (OR=2.3, 95% CI=1.0-5.4) among sewing machine operators. / Conclusion: Results are suggestive of a possible association between maternal occupational ELF-MF exposure and certain brain tumors in their offspring. / Keywords: brain tumors, occupational exposures, maternal exposures, magnetic fields, childhood cancer, job exposure matrix