Chemotaxis is the ability of an organism to sense its environment and move towards attractants and away from repellents. The two-component system controlling chemotaxis in bacteria contains a histidine kinase CheA, which is autophosphorylated in response to a signal from a ligand-bound transmembrane methyl-accepting chemotaxis protein. CheA transfers the phosphate group to its cognate response regulator which modulates flagellar rotation. Signal termination by dephosphorylation of the response regulator is necessary for the organism to react rapidly to changes in the environment. The phosphorylated response regulator CheY in <i>Escherichia coli</i> is dephosphorylated by CheZ, a phosphatase; certain organisms, such as <i>Sinorhizobium meliloti</i>, that lack a CheZ homolog have developed alternate methods of signal termination. The signaling chain of S. meliloti contains two response regulators, CheY1 and CheY2, in which CheY2 modulates flagellar rotation and CheY1 causes signal termination by acting as a phosphate sink. In addition to known chemotaxis components, the second gene in the chemotaxis operon of <i>S. meliloti</i> codes a 97 amino acid protein, called CheS. The phenotype of a cheS deletion strain is similar to that of a cheY1 deletion strain. Therefore, the possibility that CheS causes signal termination was explored in this work. The derived amino acid sequence of CheS showed similarities with its orthologs from other °-proteobacteria. Sequence conservation was highest at the centrally located °4 and °5 helices. Earlier observations that CheS localizes at the polar chemotaxis cluster in a CheA-dependent manner were confirmed, and the co-localization of CheS with CheA was demonstrated by fluorescence microscopy. The stable expression of CheS in the presence of CheA was confirmed by immunoblot. The same approach was used to establish the stable expression of CheS only in the presence of the P2 domain of CheA, but not with the P1 or P345 domains. Limited proteolysis followed by mass spectrometry defined CheA_163-256 as the CheS binding domain, and this domain overlapped the previously defined CheY2-binding domain, CheA_174-316. The role of CheS in the phosphate flux in S. meliloti chemotaxis was analyzed by assays using radio-labeled [?-?°P]ATP. CheS does not play a role in the autophosphorylation of CheA. However, CheS accelerated the rate of CheY1~P dephosphorylation by almost two-fold, but did not affect the rate of CheY2~P dephosphorylation. CheS also does not seem to affect phosphate flow in the retrophosphorylation from CheY2~P to CheA using acetyl [?°P]phosphate as phosphodonor. Since CheS increases the rate of CheY1 dephosphorylation, it can be envisioned that it either increases the association of CheY1 to CheA, increasing the flow of phosphate from CheA to CheY1, or directly accelerates the dephosphorylation of CheY1~P. The presence of a STAS domain and a conserved serine residue in CheS also raises the possibility that CheS may be phosphorylated by a yet unknown kinase, in a mechanism similar to the phosphorylation of <i>Bacillus subtilis</i> SpoIIAA by its cognate kinase SpoIIAB. Phosphorylated CheS may then switch CheA between a kinase or phosphotransferase ON/OFF state or activated CheS may directly interact with CheY1. Further studies are needed to determine the association of CheY1 with CheS to elucidate the mechanism of CheY1 dephosphorylation. This work has confirmed the <i>in vitro</i> association of CheS with CheA, determined the CheS binding domain on CheA, and indicated that CheS accelerates the dephosphorylation of CheY1~P. This has advanced our understanding of the role of CheS in the chemotaxis signaling chain of <i>S. meliloti</i>. / Master of Science

A study was conducted to examine the correlation between a novel behavior monitoring system and a validated data logger. We concluded that the behavior monitoring system was valid for tracking daily rest time in dairy cows (R=0.96); however the correlation values for rest bouts and rest duration were relatively low, (R=0.64) (R=0.47), respectively. Daily monitoring of animal activity and milk components can be used to detect mastitis prior to clinical onset. Data from 268 cases with clinical mastitis and respective controls (n=268) from Virginia Tech and the University of Florida dairy herds were examined. Variables collected included daily milk yield, electrical conductivity, milk fat, protein, and lactose percent, as well as activity measurements including daily rest time, daily rest duration, daily rest bouts, and daily steps taken. Variables were collected for case and control cows in the 14 d prior to and after clinical diagnosis, for a total 29 d monitoring period. A milk sample was aseptically collected upon detection of clinical signs as observed by milker's at both farms. A statistical method (candisc discriminant analysis) was used to combine all measurements and sensitivity and specificity was calculated. Virginia Tech cows on d -1 (sensitivity=95%, specificity=95%), Virginia Tech and University of Florida cows on d -1 (sensitivity=88%, specificity=90). Overall, daily monitoring of animal activity and milk components can detect mastitis prior to onset of clinical signs of disease. This may allow producers to intervene and make proactive management decisions regarding herd health prior to clinical diagnosis. / Master of Science

This study monitored the storage lesion of 15 units of canine platelet concentrates harvested by differential centrifugation. Canine platelet concentrates were stored at 20-24°C in a platelet rotator for a total of 9 days; the storage lesion of three second generation platelet storage containers was compared. The battery of in vitro tests used to monitor the storage lesion were selected from previous studies performed with human platelet concentrates separated by differential centrifugation. Based on these tests, canine platelet concentrates exhibited a storage lesion similar to human platelet concentrates. Metabolic analytes demonstrated decreasing pH, carbon dioxide, bicarbonate and glucose concentrations concurrent with increasing oxygen and lactate dehydrogenase activity over the 9-day period. Platelet structural changes were monitored by mean platelet volume, which began to increase on Day-5. Platelet function appeared to be compromised, as indicated by aggregation studies using collagen and adenosine diphosphate as agonists. Product sterility was maintained. There was no consensus of data supporting superior performance of one platelet storage container. This study indicates that canine platelet concentrates may be harvested by differential centrifugation of whole blood. In vitro studies utilizing three second-generation platelet storage bags support a previous study and concurs that canine platelet concentrates stored at 20-24°C using continuous agitation are viable for at least 5 days. / Master of Science

Process planning is an important and integral part of operating a printed circuit board (PCB) assembly system effectively. The focus of this research is to develop a new solution approach to determine the component placement sequence and feeder assignment for a turret style Chip Shooter machine often used in PCB assembly systems. This solution approach can be integrated into a process planning system to reduce assembly time and improve productivity. The Chip Shooter machine consists of three primary mechanisms: the turret head, a moving table, and the feeder carriage. These mechanisms move simultaneously in a cyclic manner to mount the components on the PCB. The mechanism with the longest movement time determines the placement time of a component. Therefore, the placement sequence of the components and the arrangement of the feeders in the feeder carriage directly affect the time required to mount all the components on a PCB. A placement time estimator function that accounts for the functional characteristic of the Chip Shooter machine is developed and is used to evaluate the performance of the solution approach presented in this research. The solution approach consists of a construction algorithm that uses a set of knowledge-based rules to construct an initial placement sequence and feeder assignment, and an improvement procedure to improve the initial solution. A case study is presented to validate the proposed solution approach. A Fuji CP4-3 machine and actual PCB data are used to test the performance of the proposed solution approach for different machine setup scenarios. The solutions obtained using the proposed solution approach are compared to those obtained using state of the art PCB assembly process optimization software. For all PCBs in the case study, the proposed solution approach yielded lower placement times than the commercial software, thus generating additional valuable production capacity. / Master of Science

Šio darbo tikslas yra sukurti metodą, kuris teiktų galimybę kuo didesnę vartotojo sąsajos dalį apibrėžti deklaratyviai (komponentų kūrimas, įvykių klausytojų registravimas, komponentų tarpusavio sąryšių apibrėžimas ir vizualus komponentų išdėstymas languose). Darbe išanalizuotos įvairios komponentinės architektūros bei išraiškingą vartotojo sąsajos apibrėžimą įgalinantys sprendimai. Apibrėžta ir įgyvendinta architektūra leidžianti kurti deklaratyviai apibrėžiamus vartotojo sąsajos komponentus, kurie deklaruoja savo elgesį ir gali bendrauti tarpusavyje pranešimų pagalba. Rezultate buvo sukurta sistema, kuri leidžia kurti taikomąsias programas su Java Swing vartotojo sąsaja, naudojantis beveik vien tik deklaratyviais taikomosios programos dalių apibrėžimais. Sukurtos sistemos konfigūracijos galimybės leidžia sumažinti komponentų manipuliacijai skirto Java kodo poreikį. / A part of a user interface can be created using declarative means. The main goal of this paper is to maximize that portion. To do that, said means would be used to create components, register event listeners, describe relationships between components and layout them in windows. Various component-based architectures and existing solutions for declarative user interface definition were analyzed. As a result, an architecture was defined which allows user interface components to be created using a declarative approach. These components define their behavior and use messages to communicate with each other. The outcome was a system, which can create Java Swing applications using mostly declarative definitions of various parts of said applications. This system provides various configuration options that reduce the need of writing Java code for component manipulation.

Syftet med denna uppsats är att identifiera vilka konsekvenser som uppstått i och med den praktiska implementeringen av komponentavskrivningarna i bostadsrättsföreningar. För att uppnå studiens syfte har vi utgått från en kvalitativ metod med en abduktiv ansats. Insamlingen av empirin har skett genom semistrukturerade individuella intervjuer från sex stycken ekonomer inom förvaltningsbranchen. Detta material har sedan analyserats med hjälp av teori för att slutligen uppfylla syftet. Vår slutsats är att K3-regelverket medför brister i redovisningen i Bostadsrättsföreningar och att ett nytt regelverk anpassat för den branschen är önskvärt. / The purpose of this paper is to identify the consequences of the practical implementation of ”component depreciations komponentavskrivningarna” in housing cooperatives. To acquire this purpose, we have practice a qualitative method with an abductive hypothesis. When collecting the empirical data we have been conducting semi-structured individual interviews with six economists in the investment management industry. This data has been analyzed, tied to the theological data, to satisfy the purpose The conclusion of this research implies that the implement of the regulation of K3 has caused deficiencies in the accounting in housing associations and that a new regulation, more accommodated to the industry, is desirable.

"The goal of this thesis is to extend the theory and practice of matrix completion algorithms, and how they can be utilized, improved, and scaled up to handle large data sets. Matrix completion involves predicting missing entries in real-world data matrices using the modeling assumption that the fully observed matrix is low-rank. Low-rank matrices appear across a broad selection of domains, and such a modeling assumption is similar in spirit to Principal Component Analysis. Our focus is on large scale problems, where the matrices have millions of rows and columns. In this thesis we provide new analysis for the convergence rates of matrix completion techniques using convex nuclear norm relaxation. In addition, we validate these results on both synthetic data and data from two real-world domains (recommender systems and Internet tomography). The results we obtain show that with an empirical, data-inspired understanding of various parameters in the algorithm, this matrix completion problem can be solved more efficiently than some previous theory suggests, and therefore can be extended to much larger problems with greater ease. "

The Common Tutor Object Platform (CTOP) was designed as a lightweight component framework for creating and deploying applications relating to Intelligent Tutoring Systems. The CTOP supports a runtime for intelligent tutoring system content deployment, a content development environment, an extensive reporting tool, and other smaller applications. The CTOP was designed with future development in mind, allowing easy specification of new base objects and extension points for future development. It has been used as the foundation of the Assistments Project, a wide scale server based ITS deployment. This thesis documents the software engineering aspects of the project. The Assistments Project is capable of supporting a quarter of targeted students in Massachusetts, and optimistically scalable to the entire state and beyond.

High-dimensional integrals arise in a variety of areas, including quantum physics, the physics and chemistry of molecules, statistical mechanics and more recently, in financial applications. In order to approximate multidimensional integrals, one may use Monte Carlo methods in which the quadrature points are generated randomly or quasi-Monte Carlo methods, in which points are generated deterministically. One particular class of quasi-Monte Carlo methods for multivariate integration is represented by lattice rules. Lattice rules constructed throughout this thesis allow good approximations to integrals of functions belonging to certain weighted function spaces. These function spaces were proposed as an explanation as to why integrals in many variables appear to be successfully approximated although the standard theory indicates that the number of quadrature points required for reasonable accuracy would be astronomical because of the large number of variables. The purpose of this thesis is to contribute to theoretical results regarding the construction of lattice rules for multiple integration. We consider both lattice rules for integrals over the unit cube and lattice rules suitable for integrals over Euclidean space. The research reported throughout the thesis is devoted to finding the generating vector required to produce lattice rules that have what is termed a low weighted discrepancy . In simple terms, the discrepancy is a measure of the uniformity of the distribution of the quadrature points or in other settings, a worst-case error. One of the assumptions used in these weighted function spaces is that variables are arranged in the decreasing order of their importance and the assignment of weights in this situation results in so-called product weights . In other applications it is rather the importance of group of variables that matters. This situation is modelled by using function spaces in which the weights are general . In the weighted settings mentioned above, the quality of the lattice rules is assessed by the weighted discrepancy mentioned earlier. Under appropriate conditions on the weights, the lattice rules constructed here produce a convergence rate of the error that ranges from O(n−1/2) to the (believed) optimal O(n−1+δ) for any δ gt 0, with the involved constant independent of the dimension.

<p>Embedded systems are microprocessor-based systems that cover a large range of computer systems from ultra small computer-based devices to large systems monitoring and controlling complex processes. The particular constraints that must be met by embedded systems, such as timeliness, resource-use efficiency, short time-to-market and low cost, coupled with the increasing complexity of embedded system software, demand technologies and processes that will tackle these issues. An attractive approach to manage the software complexity, increase productivity, reduce time to market and decrease development costs, lies in the adoption of the component based software engineering (CBSE) paradigm. The specific characteristics of embedded systems lead to important design issues that need to be addressed by a component model. Consequently, a component model for development of embedded systems needs to systematically address extra-functional system properties. The component model should support predictable system development and as such guarantee absence or presence of certain properties. Formal methods can be a suitable solution to guarantee the correctness and reliability of software systems.</p><p> </p><p>Following the CBSE spirit, in this thesis we introduce the ProCom component model for development of distributed embedded systems. ProCom is structured in two layers, in order to support both a high-level view of loosely coupled subsystems encapsulating complex functionality, and a low-level view of control loops with restricted functionality. These layers differ from each other in terms of execution model, communication style, synchronization etc., but also in kind of analysis which are suitable. To describe the internal behavior of a component, in a structured way, in this thesis we propose REsource Model for Embedded Systems (REMES) that describes both functional and extra-functional behavior of interacting embedded components. We also formalize the resource-wise properties of interest and show how to analyze such behavioral models against them.</p> / PROGRESS