Multiple original results in the theory of automata and formal languages are presented, dealing mainly with combinatorial problems and complexity questions related to reset words and road coloring. The other results concern jumping finite automata and related types of rewriting systems. Powered by TCPDF (www.tcpdf.org)

Tinnitus is the perception of sound in the absence of an actual sound stimulus. Recent developments have shifted the focus to the central nervous system and the neural correlate of tinnitus. Broadly, tinnitus involves cortical map rearrangement, pathological neural synchrony, and increased spontaneous firing rates. Various cortical regions, such as Heschl’s gyrus in the auditory cortex, have been found to be associated with different aspects of tinnitus, such as perception and loudness. I propose a cortical stimulation mapping study of Heschl’s gyrus using a depth and subdural electrode montage to conduct electrocorticography. This study would provide high-resolution data on abnormal frequency band oscillations characteristic of tinnitus and pinpoint regions where they occur. The validity of the neural synchrony model would also be tested in this study.

80% of all lifeguard related rescues along the beaches of northwest Florida are believed to be related to rip currents. A rip current is the strong flow of water, seaward extending from the beach to the breaker line. It has previously been shown that there are rip current hot spots at Pensacola Beach, forced by a ridge and swale topography offshore, but the annual evolution/behavior of these hotspots (i.e. location, size, frequency, and orientation) have not been examined in detail. Remote imagery from Casino Beach was rectified to a planar view in order to examine the rip channel characteristics. These characteristics were analyzed to determine variations and patterns on a daily, monthly, and seasonal basis and in relation to reset storms, wind and wave characteristics, and the beach states of Casino Beach in order to characterize the rip development and variation throughout a year. Beach states and rip configurations were impacted by many frontal storms and one tropical storm, which were classified as a reset storm when reconfigurations of the beach state and rips occurred. Given sufficient time between reset storms, the bar migrated onshore in a manner consistent with the Wright and Short (1984) model, transitioning from LBT, to RBB, and finally to TBR state. The lack of reset storms after March 2010 resulted in a large frequency of observed rip channels (64) between April and May. It is shown that these rip channels are clustered into 7 statistically significant groups based on their location alongshore at the 95 % confidence interval. It is argued that the rip channel clusters are a direct result of the wave forcing caused by the ridge and swale topography. This situation causes the bar to move onshore that without interruption of a reset storm will attach at certain locations creating a transverse bar and rip morphology. The bar appears to attach to the beach at consistent locations throughout the year creating similar rip locations and subsequently the rip clusters. The risk posed to beach users by these rip currents is concentrated in certain locations which are persistent throughout the year.

U.S. Army helicopter maintenance condition is affected by operation environment and high flight hours. Due to the environmental conditions and high operation tempo of Afghanistan and Iraq, U.S. Army Aviation created the RESET aviation maintenance program to provide restorative maintenance following deployments in theater. The RESET maintenance program was created in addition to the existing two-level maintenance programs. Following deployment, RESET is a thorough cleaning to remove contaminants, inspection of airframe and components, and repair cycle to restore the condition of the helicopter to acceptable condition. Based on the original intent of RESET, it was projected that at the conclusion of military operations in Afghanistan and Iraq, the RESET maintenance program could be discontinued. Because of the presumed safety, reliability, and mission readiness created by RESET, this thesis appraised the RESET maintenance program as a permanent addition to U.S. Army Aviation maintenance programs. The hypothesis was that RESET does improve safety, reliability, and mission readiness of the Army UH-60 Black Hawk fleet. The design was a quantitative survey of three variables: safety, reliability, and mission readiness. The survey featured Likert scale and open-ended questions of three groups: UH-60 maintenance test pilots, UH-60 AVUM/AVIM maintenance supervisory personnel, and ACE (Airframe Condition Evaluation) technical evaluators. Data from each of the three survey groups verified the hypothesis that RESET improved safety, reliability, and mission readiness. Data from open-ended questions indicated that the additional disassembly and special inspections of RESET are more extensive than the aviation unit and intermediate Phased Maintenance Inspection (PMI). Therefore, given the disassembly and special inspections of RESET, and the verification that RESET improves safety, reliability, and mission readiness, it was concluded that RESET is a successful program that should be continued. Based on the effectiveness of RESET in discovering these deficiencies, RESET should be a permanent addition to the Army aviation maintenance programs.

Web browsing has been one of the most popular activities on the internet. The increasing importance of the Web in everyday life calls for device-independent access to existing web sites. Although, there is full Web access available on mobile phones the user experience is often poor when compared to the Web user experience on Personal Computer (PC). Therfore, it is important for the Internet service provider to find the indications of user dissatisfaction from the network. While using the mobile Web, user can normally abort the transfer by pressing the stop or reset buttons in the browsers, leaving the page being downloaded by following a bookmark or can close the connection. Such events can be observed through the TCP reset (RST) flag from traffic on network level. In this thesis we have investigated the possible causes of TCP RST flags mobile Web session is interrupted. We further analyze up to what extent we can rely on TCP RST flags for being an indication of user dissatisfaction in mobile web browsing. Therefore, an experiment testbed is developed to capture the TCP packet traces during controlled active tests. Results are gathered using mobile devices with four popular mobile operating systems (OS). The trace files captured are analyzed using perl script to dicern the flow and focusing on the TCP RST flag during the flow. Further, TSTAT tool is used to validate our trace files. / 0760-882089

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Type 1 diabetes (T1D) results from the destruction of pancreatic β-cells caused by an altered immune balance in the pancreatic microenvironment. In humans as well as in mouse models, T cells are well recognized as key orchestrators of T1D, which is characterized by T helper (Th) 1 and Th17 cell bias and/or low/defective T-regulatory cells (Treg), and culminates in cytotoxic T-cell (CTL)-mediated destruction of β-cells. Refitting of immune cells toward the non-inflammatory phenotype in the pancreas may represent a way to prevent/treat T1D. Recently we developed a unique spontaneous humanized mouse model of type 1 diabetes, wherein mouse MHC-II molecules were replaced by human DQ8, and β-cells were made to express human glutamic acid decarboxylase (GAD) 65 auto-antigen. The mice spontaneously developed T1D resembling the human disease. Humanized T1D mice showed hyperglycemic (250-300 mg/dl) symptoms by the 4th week of life. The diabetogenic T cells (CD4, CD8) present in our model are GAD65 antigen-specific in nature. Intermolecular antigen spreading recorded during 3rd-6th week of age is like that observed in the human preclinical period of T1D. In this paper, we tested our hypothesis in our spontaneous humanized T1D mouse model. We targeted two cell-signaling pathways and their inhibitions: eIF5A pathway inhibition influences T helper cell dynamics toward the non-inflammatory phenotype and Notch signaling inhibition enrich Tregs and targets auto-reactive CTLs, rescues the pancreatic islet structure, and increases the functionality of β-cells in terms of insulin production. We report that inhibition of (eIF5A + Notch) signaling mediates suppression of diabetogenic T cells by inducing plasticity in CD4 + T cells co-expressing IL-17 and IFNγ (IL-17 + IFNγ +) toward the Treg cells phenotype.

藉由提供多樣式委託提供交易人直接反應各月份合約價格關係的管道，促進市場活絡, 滿足本國選擇權市場交易人的策略交易需求，增加交易誘因,有關選擇權當日有效策略交易就系統之影響及相關配套措施提出建議以利系統設計之參考及進一步研究跨市場或更複雜之策略交易研究之參考。

Original results in computational and combinatorial theory of reset words in transition systems, road coloring in directed graphs, and discontinuous input processing in formal languages are presented, including strong lower bounds on subset synchronization thresholds, lower bounds on descriptive power of jumping finite automata, and corresponding complexity classifications.

Submitted by Danielle Karla Martins Silva (danielle.martins@ufpe.br) on 2015-03-12T12:34:22Z No. of bitstreams: 2 José Sérgio Casé de Oliveira.pdf: 1717088 bytes, checksum: 91394789d8ecc6a45d75afc3abd4503c (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-12T12:34:22Z (GMT). No. of bitstreams: 2 José Sérgio Casé de Oliveira.pdf: 1717088 bytes, checksum: 91394789d8ecc6a45d75afc3abd4503c (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / CAPES / Esta dissertação tem por objetivo avaliar o poder do teste de má especificação proposto por Cribari-Neto & Lima (2007) em vários cenários que configuram má especificação do modelo de regressão beta, em particular: função de ligação incorreta, presença de outlier na amostra, omissão de variável regressora importante, estimação com dispersão constante quando o modelo verdadeiro possui dispersão variável (e vice-versa) e má especificação da distribuição da variável resposta. O desempenho do teste foi avaliado em modelos de regressão beta com dispersão fixa e variável. Adicionalmente, introduzimos um outro teste de má especificação, o qual também teve seu poder avaliado em diversos cenários de má especificação. O poder do teste proposto foi comparado ao do teste proposto por Cribari-Neto & Lima (2007). Os desempenhos dos testes em amostras finitas foram avaliados numericamente por meio de simulações de Monte Carlo. Por fim, apresentamos algumas aplicações com dados reais.