As computers keeping advancing, many difficult problems which were unable to compute formerly now have the chance to get answered. It is always the goal of mathematicians and computer scientists to compute and get the answers of the linear systems. Since 1950s, there have been a lot of published papers discussing the issue. As the linear systems larger and larger, the computer efficiency required is higher and higher, so that it is very difficult to get the answers of large linear systems. Now, the problems are showing aurora. In this dissertation, several mathematical calculations to compute the linear systems will be discussed, as well as their background and theory. Moreover, they will also be practiced.

Centrala gränsvärdessatsen (CGS) är en av grundpelarna inom statistik och sannolikhetsteori. CGS säger att ”summan av ett stort antal oberoende likafördelade slumpmässiga variabler är approximativt normalfördelad”. Det finns olika bevis för CGS. I denna uppsats kommer jag att bevisa centrala gränsvärdessatsen genom att utnyttja karaktäristiska funktioner, eftersom karaktäristiska funktioner har bra egenskaper vilket vi kommer att få se när vi definierar dem. I detta arbete har jag kopplat samman olika pusselbitar som behövs för att kunna bevisa CGS. Genom att göra det så blir det enklare för läsaren att förstå CGS mer grundläggande. / The Central Limit Theorem (CLT) is one of the pillars of statistics and probability theory. CLT states that ”the sum of a large number of independent equally distributed random variables is approximately normally distributed”. There are different proofs for CLT. In this essay I will prove the central limit theorem by utilizing characteristic functions, since characteristic functions have good features, which we will see when defining them. In this paper I have linked various pieces of the puzzle needed to prove CLT. By doing so it becomes easier for readers to gain a deeper understanding of CLT.

The goal of this research project was to contribute to the understanding of CuGaSe2/CdS photovoltaic devices, and to improve the performance of these devices. The initial part of the research dealt with the optimization of a Sequential Deposition process for CuIn(Ga)Se2 absorber formation. As an extension of this, a recipe (Type I Process) for CuGaSe2 absorber layer fabrication was developed, and the deposition parameters were optimized. Electrical characterization of the thin films and completed devices was carried out using techniques such as Two-Probe and Three-Probe Current-Voltage, Capacitance-Frequency, Capacitance-Voltage, and Spectral Response measurements. Structural/chemical characterization was done using XRD and EDS analysis. Current densities of up to 15.2 mA/cm2, and Fill Factors of up to 58% were obtained using the Type I CuGaSe2 Process. VOC's, however, were limited to less than 700 mV. Several process variations, such as changes in the rate/order/temperature of depositions and changes in the thickness of layers, resulted in little improvement. With the aim of breaking through this VOC performance ceiling, a new absorber recipe (Type II Process) was developed. VOC's of up to 735 mV without annealing, and those of up to 775 mV after annealing, were observed. Fill Factors were comparable to those obtained with Type I Process, whereas the Current Densities were found to be reduced (typically, 10-12 mA/cm2, with the best value of 12.6 mA/cm2). This performance of Type II devices was correlated to a better intermixing of the elements during the absorber formation. To gain an understanding of the performance limitations, two simulation techniques, viz. SCAPS and AMPS, were used to model our devices. Several processing experiments and SCAPS modeling indicate that a defective interface between CuGaSe2 and CdS, and perhaps a defective absorber layer, are the cause of the VOC limitation. AMPS simulation studies, on the other hand, suggest that the back contact is limiting the performance. Attempts to change the physical back contact, by changes in the absorber processing, were unsuccessful. Processing experiments and simulations also suggest that the CuGaSe2/CdS solar cell involves a true heterojunction between these two layers.

Mongolian SME sector is an important part of its private sector that effectively contributes to the outcome of Mongolian economy. Like SMEs in other countries, SMEs in Mongolia face challenge of accessing to finance and this is the most constraint for their continuous growth. While credit guarantee schemes, by filling this gap, became one of the most effective SME promoting tools for the governments of many developed and developing countries, Mongolian government has not been institutionalizing such schemes yet. This study investigates the feasibility of Mongolian government to establish a state-funded CGS in order to facilitate SMEs access to finance. This research based on questionnaire survey conducted from 316 SMEs in urban and rural areas of Mongolia in late 2011. SMEs need for financing, demand for guarantee services and their attitude toward establishing the CGS in Mongolia were investigated. Also, two officials from ¡§SME Fund¡¨ and ¡§SME Support Agency¡¨ were interviewed to analyze their attitude on feasibility of institutionalizing the CGS with the support of Mongolian government. The study showed that there is a high demand for additional financing and credit guarantees in SME sector. The findings suggested that the government urgently needs to institutionalize CGS to solve financial challenges of SMEs. As the most appropriate type of CGSs for Mongolian environment found was a ¡§Public CGS¡¨.

abstract: Present day Internet Protocol (IP) based video transport and dissemination systems are heterogeneous in that they differ in network bandwidth, display resolutions and processing capabilities. One important objective in such an environment is the flexible adaptation of once-encoded content and to achieve this, one popular method is the scalable video coding (SVC) technique. The SVC extension of the H.264/AVC standard has higher compression efficiency when compared to the previous scalable video standards. The network transport of 3D video, which is obtained by superimposing two views of a video scene, poses significant challenges due to the increased video data compared to conventional single-view video. Addressing these challenges requires a thorough understanding of the traffic and multiplexing characteristics of the different representation formats of 3D video. In this study, H.264 quality scalability and multiview representation formats are examined. As H.264/AVC, it's SVC and multiview extensions are expected to become widely adopted for the network transport of video, it is important to thoroughly study their network traffic characteristics, including the bit rate variability. Primarily the focus is on the SVC amendment of the H.264/AVC standard, with particular focus on Coarse-Grain Scalability (CGS) and Medium-Grain Scalability (MGS). In this study, we report on a large-scale study of the rate-distortion (RD) and rate variability-distortion (VD) characteristics of CGS and MGS. We also examine the RD and VD characteristics of three main multiview (3D) representation formats. Specifically, we compare multiview video (MV) representation and encoding, frame sequential (FS) representation, and side-by-side (SBS) representation; whereby conventional single-view encoding is employed for the FS and SBS representations. As a last step, we also examine Video traffic modeling which plays a major part in network traffic analysis. It is imperative to network design and simulation, providing Quality of Service (QoS) to network applications, besides providing insights into the coding process and structure of video sequences. We propose our models on top of the recent unified traffic model developed by Dai et al. [1], for modeling MPEG-4 and H.264 VBR video traffic. We exploit the hierarchical predication structure inherent in H.264 for intra-GoP (group of pictures) analysis. / Dissertation/Thesis / Ph.D. Electrical Engineering 2012

No description available.

In der vorliegenden Arbeit wird ausgehend vom Stand der Wissenschaft und Technik für Ver-fahren und Werkstoffe des Titanlötens das Kaltgasspritzen in seiner Eignung als Vorbelo-tungsprozess beim löttechnischen Fügen von Titanlegierungen untersucht und qualifiziert. Die Parameter des Beschichtungsvorgangs werden dabei mit den resultierenden Schichtgefügen und späteren Lötergebnissen korreliert, wodurch eine Bewertung ermöglicht und ein Beitrag zum Verständnis der Mechanismen einer spritztechnischen Vorbelotung geliefert wird. Es werden dabei sowohl materialografische als auch mechanische Charakterisierungen durchge-führt. Ergänzt werden die Arbeitspunkte durch eine hochauflösende TEM-Untersuchung der Grenzfläche von kaltgasgespritzten Zink-Schichten und Aluminium-Substraten, die der Über-prüfung theoretischer Erkenntnisse zum Haftungsmechanismus kaltgasgespritzter metallischer Schichten auf Leichtmetallsubstraten dient. Die Arbeit schließt mit einer Diskussion und Fol-gerung und gibt Empfehlungen für weiterführende Forschungen auf diesem Gebiet. / The present work qualifies the cold gas dynamic spray process (CGS) as a process for the application of braze filler coatings onto titanium alloy substrates. The work program results from needs and problems that were identified in the state-of-the-art of science and technology. The parameters of the coating process are correlated with the resulting coating microstruc-tures and the posterior brazing results. Materialographic and mechanic characterisations of the filler coatings and braze seams are carried out. Thereby, an evaluation of the braze filler ap-plication by cold gas spraying is permitted. In addition, high-resolution TEM investigations within the interfaces of a cold sprayed zinc coating and an aluminium base material proof the theory of the bonding mechanisms of CGS coatings on light weight metals. The work dis-cusses the achieved results and gives an outlook to continuative investigations in this field of science.

Die vorliegende Arbeit beschäftigt sich mit dem Einfluss der NMDA-Rezeptorantagonisten, Memantin, MK-801, CGS und Ifenprodil auf die hypoxieinduzierte Zellschädigung an kortikalen Zellen der Ratte. Außerdem wurde der Einfluss von subtoxischen Konzentrationen von NMDA sowie von Roscovitin, einem Hemmer Cyclin-abhängiger Kinasen, auf die hypoxiebedingte Zellschädigung untersucht. Ziel dieser Arbeit war es, die neuroprotektive Wirkung dieser Substanzen zu erfassen. Zur Untersuchung der hypoxischen Schädigung wurden zwei 48-Well-Zellkulturplatten mit 15 Tage alten kortikalen Zellen der Ratte verwendet. Eine Kulturplatte wurde für vier Stunden mit HEPES(N-2-Hydroxyethylpiperazine-N’-2-Ethansulfonsäure)-Puffer (ohne Glucose) unter hypoxischen Bedingungen inkubiert. Die zweite Platte, mit glukorisiertem HEPES-Puffer, wurde für vier Stunden unter normoxischen Bedingungen inkubiert. Der HEPES-Puffer wurde nach vier Stunden entfernt, die Kulturplatten mit Dulbecco’s Modified Eagle Medium (DMEM) gewaschen und mit diesem Medium für 24 Stunden unter normoxischen Bedingungen inkubiert. Anschließend wurde das Medium ent¬fernt, durch NMDA, Memantin, Roscovitin, CGS und Ifenprodil ersetzt und die Ansätze für weitere 24 Stunden unter normoxischen Bedingungen inkubiert. Zur Beurteilung der Zellschädigung wurden der Aktivitätsanstieg der Laktat-Dehydrogenase (LDH), die Freisetzung freier Sauerstoffradikale und die Steigerung der Caspase-Aktivität bestimmt. Während die Bestimmung der LDH-Aktivität und die Freisetzung der freien Sauer¬stoff¬radikale nekrotische Veränderungen der Zellen charakterisiert, zeigt eine Zunahme der Caspase-Aktivität apoptotische Vorgänge an. LDH ist ein stabiles zytoplasmatisches Enzym, das in fast allen Körperzellen vorkommt. Beim Absterben der Zelle wird das Enzym durch die Schädigung der Plasmamembran aus der Zelle freigesetzt, so dass es zu einem Anstieg der LDH-Aktivität proportional zur Anzahl der toten Zellen kommt. Diese Aktivität wurde spektrophotometrisch mit einem Mikrotiterplatten-Lesegerät bestimmt. Die Ergebnisse des LDH-Tests zeigen, dass nach der 24-stündigen Behandlung der Zellen mit MK-801 die LDH-Aktivität um 11%, bei Roscovitin um 13%, bei Memantin (5 µM) um 56%, bei Memantin (0,5 µM) um 52% und mit NMDA (5 µM) um 44% signifikant vermindert wurde. Bei einer hypoxiebedingten Schädigung kortikaler Zellen kommt es auch zur Bildung freier Sauer¬stoff¬radikale. 2’,7’-Dichlorfluorescein Diacetat (2’,7’-H2DCF-DA) wird von den Zellen auf¬ge¬nommen und intrazellulär mit Sauerstoff- und Stickstoffspezies zum Fluoreszenz¬farb-stoff 2’,7’-Dichlorodihydrofluorescein (DCF) deacetyliert. DCF verbleibt dabei in den Zellen, so dass die Messung der Fluoreszenz der Zellen als Maß für intrazelluläre Oxidationsprozesse verwendet werden kann. Die DCF-Fluoreszenz-Änderung wurde mittels eines Fluorimeters gemessen und die daraus resultierenden Daten mit einer im Fluorimeter integrierten Software bearbeitet. Die Ergebnisse zeigen, dass die Freisetzung der freien Sauerstoffradikale, der hypoxiegeschädigten Zellen, signifikant durch Ifenprodil (10 µM) um 119%, Memantin (50 µM) um 88% und NMDA (5 µM) um 134% reduziert wurde. Die hypoxieinduzierte Zellmembranschädigung führt desweiteren zu einem Anstieg der Caspase-Aktivität. Mit Hilfe des Apo-One Homogeneous Caspase-3/7-Assays (Promega) wurde die Aktivität der Caspasen 3 und 7 fluorimetrisch bestimmt. Um die unterschiedliche Zelldichte in den Kulturschalen zu berücksichtigen, wurde eine Proteinbestimmung nach der Bicinchoninsäure-Methode (Smith et al. 1985) durchgeführt. Einen protektiven Effekt auf die Zellschädigung zeigen Memantin und NMDA in Bezug auf die Beeinflussung dieser Caspase-Aktivität. Der hypoxiebedingte Anstieg der Caspase-3-Aktivität konnte nach 24-stündiger Inkubation mit Memantin (5 µM) um 24%, mit Memantin (0,5 µM) um 28% und mit NMDA (5 µM) um 24% vermindert werden. CGS hat in diesen Versuchen keinen protektiven Einfluss auf die hypoxie¬induzierte Zellschädigung. Diese Arbeit zeigt, dass die Applikation niedriger NMDA-Konzentrationen neuroprotektive Effekte auf die Entwicklung der hypoxischen Schädigung von kortikalen Zellen der Ratte hat. Darüber hinaus wird vermutet, dass NMDA sogar einen trophischen Effekt auf das Über-leben der kortikalen Neurone ausübt. Dieser schützende Mechanismus von NMDA scheint denselben, wenn nicht sogar einen größeren protektiven Effekt wie Memantin zu induzieren. Um die Therapiemöglichkeiten der zerebralen Hypoxie durch neuroprotektive Medikamente zu optimieren, wären jedoch weitergehende Untersuchungen besonders als In-vivo-Modelle wünschenswert.

Made available in DSpace on 2015-05-14T12:59:54Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2521222 bytes, checksum: cfc5f6c38f54dd1ac44a377a98ba266e (MD5) Previous issue date: 2012-08-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of this study was to evaluate the mechanism of vasorrelaxante 6 - [(E) - styryl] - 2 - pyrone (pyrone-198), a natural estirilpirona isolated from the fruit of Aniba panurensis (Meisn.) Mez (Lauraceae), with protocols in normotensive rats in vivo and in vitro on the superior mesenteric artery rings isolated from rats. In non-anesthetized normotensive rats, 198-pyrone (10, 20, 30 and 40 mg / kg; iv) induced bradycardia and hypotension. In the superior mesenteric artery rings isolated from rats pyrone-198 (1 nM - 1 mM) induced relaxation of contractions induced by phenylephrine (Phe, 10 mM) concentration dependent manner and this effect was significantly attenuated after removal of the vascular endothelium. A similar effect occurred in rings pre-contracted with 1 mM of Phe, an effect significantly attenuated after removal of the endothelium. In the presence of 100 mM of L-NAME, 10  M ODQ, 300 mM of PTIO, the relaxation was attenuated. The effect of blocking with L-NAME was completely reversed in preparations with 1 mM L-arginine. In the presence of atropine (1 nM) and indomethacin (10 M), the response induced by pyrone-198 was not changed. The pyrone-198 inhibited contractions induced by increasing concentrations of Phe (1 nM - 1 mM) as well as the relaxation induced contractions induced by U46619 (10 M). In rings pre-contracted with S (-) Bay K8644 (200 nM) caused a relaxation pyrone the like, in rings pre-contracted with Phe (1 and 10 mM) in the presence of nifedipine. The pyrone-198 also interfered in the release of Ca+2 from intracellular stores mediated by Phe (1 and 10 M). In preparations incubated with 3 mM TEA and pre-contracted with 1 M Phe, relaxation of pyrone-198 was not attenuated, unlike the rings incubated with 3 mM TEA and pre-contracted with FEN 10  M. In preparations without endothelium preincubated with 1 mM TEA, relaxation to pyrone-198 was significantly attenuated, however, in the ring without endothelium preincubation with BaCl2 (30 M), 4-AP (1 mM) or GLIB (10 M) did not alter the relaxation induced by pyrone-198. The results suggest the action of pyrone-198 on hemodynamic parameters, alémde vasorrelaxante present a potent effect, an effect mediated in part by endothelium-dependent mechanisms involving via eNOS / CGs. But also by mechanisms independent of the vascular endothelium and the ability to promote relaxation in vascular smooth muscle seems to act interfering with contractile mechanisms subsequent to the entry of calcium, prinicpalmente by inhibiting the release of Ca+2 from intracellular stores sensitive to IP3, and engagement channels sensitive potassium calcium, these effects with different presentation by submaximal and maximal concentrations of phenylephrine. / O objetivo deste estudo foi avaliar o mecanismo vasorrelaxante da 6 [(E) estiril] - 2 - pirona (pirona-198), uma estirilpirona natural isolada a partir dos frutos de Aniba panurensis (Meisn.) Mez (Lauraceae), com protocolos in vivo em ratos normotensos e in vitro sobre anéis de artéria mesentérica superior isolada de ratos. Em ratos normotensos não anestesiados, pirona-198 (10, 20, 30 e 40 mg/kg, i.v.) induziu hipotensão e bradicardia. Em anéis de artéria mesentérica superior isolada de rato, pirona-198 (1 nM - 1 μM) induziu relaxamento das contrações induzidas por fenilefrina (FEN, 10 μM) de maneira dependente de concentração e esse efeito foi significativamente atenuado após a remoção do endotélio vascular. Efeito semelhante ocorreu em anéis pré-contraidos com 1 μM de FEN 7, efeito significativamente atenuado após a remoção do endotélio. Na presença de 100 μM de L- NAME, 10 M de ODQ, 300 μM de PTIO, o relaxamento foi atenuado. O efeito do bloqueio com L-NAME foi completamente revertido em preparações com 1 mM de L-arginina. Na presença de atropina (1 nM) e indometacina (10 M), a resposta induzida pela pirona-198 não foi alterada. A pirona-198 inibiu contrações induzidas por concentrações crescentes de FEN (1 nM 1 mM), como também induziu relaxamento nas contrações induzidas por U46619 (10 M). Em anéis pré-contraídos com S(-) Bay K8644 (200 nM), a pirona promoveu relaxamento tal como, em anéis pré-contraidos com FEN (1 e 10 μM) na presença de nifedipino. A pirona-198 também interferiu na liberação do Ca+2 dos estoques intracelulares mediado por FEN (1 e 10 M). Em preparações incubadas com TEA 3 mM e pré-contraídas com 1 M FEN, o relaxamento da pirona-198 não foi atenuado, diferentemente dos anéis incubados com TEA 3 mM e pré-contraídos com FEN 10 M. Em preparações sem endotélio pré-incubadas com 1 mM de TEA, o relaxamento para pirona-198 foi significantemente atenuado, entretanto, nos anéis sem endotélio a pré-incubação com BaCl2 (30 M), 4-AP (1 mM) ou GLIB (10 M) não modificou o relaxamento induzido pela pirona-198. Os resultados sugerem a ação da pirona-198 sobre os parâmetros hemodinâmicos, alémde apresentar um potente efeito vasorrelaxante, efeito este mediado parcialmente por mecanismos dependentes do endotélio, envolvendo a via eNOS/CGs. Como também por mecanismos independentes do endotélio vascular e essa capacidade de promover relaxamento no músculo liso vascular parece atuar interferindo em mecanismos contratéis posteriores à entrada de cálcio, prinicpalmente pela inibição da liberação de Ca+2 dos estoques intracelulares sensíveis ao IP3, e envolvimento dos canais de potássio sensíveis ao cálcio, efeitos estes com apresentação diferente mediante as concentrações submáxima e máxima de fenilefrina.

NITSOL: A Newton Iterative Solver for Nonlinear Systems describes an algorithm for solving nonlinear systems. Michael Pernice and Homer F. Walker, the authors of the paper NITSOL [3], implemented this algorithm in FORTRAN. The goal of the project has been to use the modern and robust language MATLAB to implement the NITSOL algorithm. In this paper, the main mathematical and algorithmic background for understanding NITSOL are described, and a user guide is included outlining how to use the MATLAB implementation of NITSOL. A nonlinear system example problem, the 2D Bratu problem, and the solution obtained by MATLAB NITSOL's are also included.