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This thesis presents distribution strategies for pursuit evasion games of networked multi-agent systems. The strategies are designed for both obstacle-free and obstacle-cluttered environments, leveraging potential maps as a method. The effectiveness of the proposed strategies was eval- uated through simulation and analysis, and the result is that combining a potential map and position extrapolation for obstacle avoidance was very successful at producing competent autonomous agents, and very com- patible when combined with specifically tailored pursuer algorithms for seeking and capture

国立情報学研究所で電子化したコンテンツを使用している。

While the Kelvin Probe (KP) has been used in a variety of surface scanning applications, the use of the KP in reinforced concrete structures to detect corrosion has been pioneered by previous work performed at the University of South Florida. However, in that work, the scale and construction of the probes was not suited to use in the field. This is primarily attributable to the small operating disk-to-concrete gap which would make the probe unable to accommodate road conditions, such as irregularities in the grading of the road, and local pitting of the surface. Therefore, it was important to investigate whether the KP can be scaled up while still maintaining resolution and fidelity of the measurements taken. The new mobile KP prototype (MKPP) constructed in this work, has a sensing disk that is approximately 10 cm in diameter and is capable of operating up to 2 cm above the concrete surface. Testing consisted of mapping an instrumented test slab simulating a corroding concrete bridge deck, at a rate of travel of about 0.6 mph (~1 ft/s) over the slab surface. The potential map generated through use of the MKPP successfully identified the corroding spot, the location of which was verified using the traditional half-cell potential mapping method outlined in ASTM C 876-09. The MKPP mapping in these trials was approximately 10 times faster than when using the traditional method. The faster potential mapping by the MKPP, while still identifying corroding sites, should allow for more economical and less intrusive survey of the condition of bridge decks. The work set the necessary proof of concept for future demonstration of an array of such probes which would further magnify the beneficial effect.

Ion traps can easily be miniaturized to become portable mass spectrometers. Trapped ions can be ejected by adjusting voltage settings of the radiofrequency (RF) signal applied to the electrodes. Several ion trap designs include the quadrupole ion trap (QIT), cylindrical ion trap (CIT), linear ion trap (LIT), rectilinear ion trap (RIT), toroidal ion trap, and cylindrical toroidal ion trap. Although toroidal ion traps are being used more widely in miniaturized mass spectrometers, there is a lack of fundamental understanding of how the toroidal electric field affects ion motion, and therefore, the ion trap's performance as a mass analyzer. Simulation programs can be used to discover how traps with toroidal geometry can be optimized. Potential mapping, field calculations, and simulations of ion motion were used to compare three types of toroidal ion traps: a symmetric and an asymmetric trap made using hyperbolic electrodes, and a simplified trap made using cylindrical electrodes. Toroidal harmonics, which represent solutions to the Laplace equation in a toroidal coordinate system, may be useful to understand toroidal ion traps. Ion trapping and ion motion simulations were performed in a time-varying electric potential representing the symmetric, second-order toroidal harmonic of the second kind—the solution most analogous to the conventional, Cartesian quadrupole. This potential distribution, which we call the toroidal quadrupole, demonstrated non-ideal features in the stability diagram of the toroidal quadrupole which were similar to that for conventional ion traps with higher-order field contributions. To eliminate or reduce these non-ideal features, other solutions to the Laplace equation can be added to the toroidal quadrupole, namely the toroidal dipole, toroidal hexapole, toroidal octopole, and toroidal decapole. The addition of a toroidal hexapole component to the toroidal quadrupole provides improvement in ion trapping, and is expected to play an important role in optimizing the performance of all types of toroidal ion trap mass spectrometers.The cylindrical toroidal ion trap has been miniaturized for a portable mass spectrometer. The first miniaturized version (r0 and z0 reduced by 1/3) used the same central electrode and alignment sleeve as the original design, but it had too high of capacitance for the desired RF frequency. The second miniaturized version (R, r0, and z0 reduced by 1/3) was designed with much less capacitance, but several issues including electrode alignment and sample pressure control caused the mass spectra to have poor resolution. The third miniaturized design used a different alignment method, and its efficiency still needs to be improved.

The relative contributions of bedrock geology, radiometric uranium, till permeability and surficial geology were assessed as predictors of radon in indoor air in the Halifax Regional Municipality (HRM), NS, Canada. Bedrock geology and radiometric uranium were statistically significant predictors (14.4%) of indoor radon, based on available indoor radon data. Permeability was not among the predictors, which was surprising given its importance in past studies. In a follow up field analogue study done in laboratory columns, the permeability and diffusivity, as gas transport mechanisms, were found, as suspected, to be important drivers on the concentrations of radon-222 detected. Given the variable thickness of till in the HRM (< 0.5 m to > 3 m), these experiments highlighted the significance of till thickness, composition, and permeability in predicting the radioactive radon-222 potential.

Thesis (Ph. D.)--Helsinky Univ. of Technology, 2001. / Title from title screen (viewed Oct. 14, 2005). Includes bibliographical references.

INTRODUÇÃO: A terapia de ressincronização cardíaca (TRC) é procedimento já incorporado às diretrizes do tratamento da insuficiência cardíaca crônica grave. Os efeitos sobre a repolarização ventricular são controversos e seu comportamento ainda precisa ser melhor definido por meios não invasivos. OBJETIVO: Analisar o comportamento da repolarização ventricular, através do mapeamento eletrocardiográfico de superfície (MES), em pacientes sob TRC. MÉTODOS: Foram estudados 52 pacientes sob TRC com indicação classe I das Diretrizes Brasileiras de Dispositivos Cardíacos Eletrônicos Implantáveis-2007, com idade média 58,8±12,3 anos, 31 homens, FEVE:27,5±9,2 e QRS:181,5±24,2ms. Foram excluídos os que não eram classe I e também os que usavam amiodarona, portadores de fibrilação atrial, marcapasso ou CDI prévios. O MES de 87 derivações (59 no tórax anterior e 28 no dorso) foi realizado em ritmo sinusal (BASAL) e sob efeito do ressincronizador (BIV) Através de medidas semiautomáticas foram obtidos o intervalo QT, QTc médio e a dispersão de QT (DQT) global das 87 derivações, nos dois modos de estimulação, em cada paciente. As mesmas medidas foram realizadas e comparadas nas três regiões discriminadas pelo MES (VD, Septo e VE). Caracterizamos assim, o comportamento global e regional do QT e sua dispersão na TRC. Utilizamos os testes t Student pareado e ANOVA para comparações múltiplas. Nível de significância de p< 0,05. RESULTADOS: O comportamento global do QTmédio foi sensivelmente menor em BIV que no BASAL (424,4±38,7 x 455,8±46,5ms; p<0,001), assim como o QTc médio (460,7±42,3 x 483,8±41,4ms; p<0,05) e a DQT (61,2±26,2 x 74,9±28,7ms; p<0,05). O QTmédio foi semelhante nas 3 regiões nos modos BASAL e BIV (p=ns), porém o QTc médio nas regiõess VD e VE mostrou-se significantemente menor no modo BASAL. Sob BIV, essa diferença foi notavelmente menor na região do VD. A DQT, em região do VE, por sua vez, foi significantemente menor em relação ao Septo, nos dois modos (BASAL: 40,5±23,1 x 55,7±28,7ms, p<0,01 e BIV: 30,6±20,4 x 47,1±20,2ms, p<0,001). A variação de efeito (D%) da TRC determinou redução do QTmédio nas 3 regiões (VD: p=0,0014; Septo: p=0,0001 e VE: p=0,0018), enquanto a DQT reduziu-se em VD: p=0,04 e VE: p=0,023. Em região septal, a redução da DQT não atingiu significância, embora tenha mostrado a mesma tendência de resposta. CONCLUSÃO: O Mapeamento Eletrocardiográfico de Superfície detectou redução global e regional dos valores da repolarização ventricular, através da análise do QTm, QTcm e DQT, por efeito da terapia de ressincronização cardíaca em pacientes com insuficiência cardíaca grave e BRE / BACKGROUND: Cardiac resynchronization therapy (CRT) is an already established procedure, which became part of the guidelines for severe chronic heart failure treatment. Its effects upon the ventricular repolarization are controversial, therefore CRT response still remains to be better defined by noninvasive methods. OBJECTIVE: The aim of this study was to analyze the ventricular repolarization response by body surface potential mapping (BSPM) in patients undergoing CRT. METHODS: Fifty-two patients undergoing CRT, mean age 58.8±12.3 years, 31 male, LVEF 27.5±9.2 and QRS duration 181.5±14.2ms, with indication class I of the 2007Guidelines for Implantable Electronic Cardiac Devices of the Brazilian Society of Cardiology, were studied. Those who were not in class I and/or in use of amiodarone, with atrial fibrillation, or with previous pacemaker or ICD, were excluded. Eighty-seven-lead BSPM examination (59 leads on the anterior chest and 28 on the back) was performed in sinus rhythm (BASELINE), and in biventricular pacing (BIV) with the resynchronization device on. Global values of QT and mean QTc intervals, and QT dispersion (DQT) were semiautomatically measured in all patients in the two pacing modes. Same measurements were made and compared in the three regions (RV, Septum and LV) discriminated by BSPM maps. Thus we characterized the global and regional QT response and its dispersion under CRT. t-Student paired test and ANOVA were used for multiple comparisons. Significance level: p<.05. RESULTS: The global mean QT response was considerably smaller in BIV pacing than in BASELINE (424.4±38.7 x 455.8±46.5ms; p<.001), and so were the mean QTc (460.7±42.3 x 483.8±41.4ms; p<.05) and DQT (61.2±26.2 x 74.9±28.7ms; p<.05). Mean QT was similar across the three regions in both pacing modes (p=ns); however, mean QTc in RV and LV regions was found to be significantly smaller in BASELINE. In BIV pacing such difference was considerably smaller in the RV region. On the other hand, DQT value in the LV region was significantly smaller compared to the Septum region in both modes (BASELINE 40.5±23.1 x 55.7±28.7ms. p<.01; and BIV 30.6±20.4 x 47.1±20.2ms. p<.001). Variation of CRT effect (D%) determined reduction of mean QT in the three regions, RV (p=.0014); Septum (p=.0001); and LV (p=.0018), while DQT was reduced in RV (p=.04) and LV (p=.023) regions. DQT reduction in the septal region was not significant, although it showed the same trend of response. CONCLUSION: body surface potential mapping detected reduction of global and regional ventricular repolarization values by analyzing QTm, QTcm and DQT variables under the effect of cardiac resynchronization therapy, in patients with severe heart failure and LBBB

INTRODUÇÃO: Os benefícios na morbi-mortalidade obtidos pela terapia de ressincronização cardíaca (TRC) em pacientes com insuficiência cardíaca estão bem estabelecidos. Métodos invasivos e não invasivos têm sido utilizados para identificar aqueles que realmente se beneficiarão da TRC, mas 30% destes pacientes não apresentam melhora clínica/funcional. Poucos estudos avaliaram o comportamento elétrico dos pacientes submetidos à TRC. OBJETIVO: Utilizamos um método não invasivo, o mapeamento eletrocardiográfico de superfície (MES) para caracterizar o padrão da ativação elétrica ventricular em pacientes após a TRC. MÉTODOS: Estudamos 91 pacientes submetidos à TRC, com insuficiência cardíaca e bloqueio de ramo esquerdo (BRE), sendo 36 excluídos devido a FA (20), BRD (3), cardiopatias hipertrófica (3) e congênita (1) ou dependentes de marcapasso antes da TRC (9). Idade média:61±10 anos, FEVE:0,28±0,9, QRS:182±24ms, classe funcional NYHA: III(78%) e IV(22%). Com o ressincronizador ligado e desligado, todos realizaram o MES, o qual fornece 87 derivações simultâneas (58 anteriores e 29 posteriores). Os mapas isócronos obtidos pelo MES forneceram os tempos de ativação ventricular (TAV) global máximo e médio nas 87 derivações. Os TAVs obtidos foram regionalizados, sendo calculados os valores médios nas áreas do VD, do septo e do VE. Analisamos a diferença do TAV entre o VD e o VE, entre o septo e o VD e entre o septo e o VE, definidos como TAV Inter-Regional. Utilizados os testes de Mann-Whitney, Kruskall-Wallis, Fisher. Nível de significância: P0.05. RESULTADOS: O MES durante ritmo sinusal e BRE mostrou que os pacientes apresentavam prolongado TAV Global máximo e médio (138ms e 64,8ms, respectivamente) com significativa diferença Regional (54,5 x 56,4 x 95,9ms; p<0,0001; VD, septo e VE, respectivamente). A TRC reduziu o TAV Global máximo (138ms x 131ms; p=0,007) e o TAV Regional do VE (95,9 x 77,3ms; p=0,001). Houve aumento do TAV Regional do VD (54,5 x 78,9ms; p=0,001), sem alteração do TAV Regional do septo (56,4 x 59,6ms; p=ns). O comportamento do TAV Inter-Regional foi: Redução do TAV VE-VD (43,8 x 17,0ms; p=0,001) e do TAV septo-VE (42,6 x 16,3ms; p=0,001) e aumento do TAV septo-VD (6,9 x 16,0ms; p=0,002). CONCLUSÃO: O Mapeamento Eletrocardiográfico de Superfície possibilitou a caracterização detalhada da ativação elétrica ventricular de pacientes portadores de ressincronizador cardíaco através do comportamento elétrico global, regional e Inter-Regional durante ritmo sinusal com bloqueio de ramo esquerdo e estimulação biventricular / INTRODUCTION: The benefits of lower morbidity and mortality obtained with cardiac resynchronization therapy (CRT) in patients with heart failure are already well established. Invasive and noninvasive methods have been used to identify those who will really benefit from CRT, however 30% of these patients do not improve clinically/functionally. Few studies evaluated the cardiac electrical development of patients undergoing CRT. OBJECTIVE: To obtain through the body surface potential mapping (BSPM), a noninvasive approach, characterization of the ventricular electrical activation development in patients after CRT. METHODS: We studied 91 patients with heart failure and left bundle-branch block (LBBB) who underwent CRT, 36 of whom were excluded for AF (20), RBBB (3), hypertrophic (3) or congenital (1) cardiomyopathy, or depended upon a pacemaker before CRT (9). Mean age was 61±10 years, LVEF 0.28±0.9, QRSd 182±24ms, NYHA functional class III(78%) and IV(22%). All underwent BSPM examination of 87 simultaneous leads (58 on the anterior chest, 29 on the back) with the resynchronization device on, then in intrinsic rhythm and LBBB (device off). The BSPM isochronal maps provided maximal and mean global ventricular activation times (VAT) for all the 87 leads. From VATs thus obtained, separate mean values for the RV, septum and LV areas were then calculated. VAT differences between RV-LV, septum-RV and septum-LV, were analyzed and denominated inter-regional VATs. Mann-Whitney, Kruskall-Wallis and Fisher statistics were used, with P.05 established as the significance level. RESULTS: During sinus rhythm/LBBB the BSPM showed patients evidencing prolonged maximal and mean global VATs (138ms and 64.8ms, respectively), with significant regional differences (54.5 vs 56.4 vs 95.9ms; RV, septum and LV, respectively; p<0.0001). CRT reduced the maximal global VAT (138ms vs 131ms; p=0.007) and the LV regional VAT (95.9 vs 77.3ms; p=0.001). The RV regional VAT increased (54.5 vs 78.9ms; p=0.001), with no alteration of the septum regional VAT (56.4 vs 59.6ms; p=ns). The inter-regional VAT developed as follows: decrease in VATLV-RV (43.8 vs 17.0ms; p=0.001) and VATseptum-LV (42.6 vs 16.3ms; p=0.001), and increase in VATseptum-RV (6.9 vs 16.0ms; p=0.002). CONCLUSION: The body surface potential mapping permitted a detailed characterization of the ventricular electrical activation of patients carrying a cardiac resynchronization device, by mapping the global, regional and inter-regional electrical activation development during sinus rhythm with left bundle-branch block, and in biventricular pacing

INTRODUÇÃO: Os benefícios na morbi-mortalidade obtidos pela terapia de ressincronização cardíaca (TRC) em pacientes com insuficiência cardíaca estão bem estabelecidos. Métodos invasivos e não invasivos têm sido utilizados para identificar aqueles que realmente se beneficiarão da TRC, mas 30% destes pacientes não apresentam melhora clínica/funcional. Poucos estudos avaliaram o comportamento elétrico dos pacientes submetidos à TRC. OBJETIVO: Utilizamos um método não invasivo, o mapeamento eletrocardiográfico de superfície (MES) para caracterizar o padrão da ativação elétrica ventricular em pacientes após a TRC. MÉTODOS: Estudamos 91 pacientes submetidos à TRC, com insuficiência cardíaca e bloqueio de ramo esquerdo (BRE), sendo 36 excluídos devido a FA (20), BRD (3), cardiopatias hipertrófica (3) e congênita (1) ou dependentes de marcapasso antes da TRC (9). Idade média:61±10 anos, FEVE:0,28±0,9, QRS:182±24ms, classe funcional NYHA: III(78%) e IV(22%). Com o ressincronizador ligado e desligado, todos realizaram o MES, o qual fornece 87 derivações simultâneas (58 anteriores e 29 posteriores). Os mapas isócronos obtidos pelo MES forneceram os tempos de ativação ventricular (TAV) global máximo e médio nas 87 derivações. Os TAVs obtidos foram regionalizados, sendo calculados os valores médios nas áreas do VD, do septo e do VE. Analisamos a diferença do TAV entre o VD e o VE, entre o septo e o VD e entre o septo e o VE, definidos como TAV Inter-Regional. Utilizados os testes de Mann-Whitney, Kruskall-Wallis, Fisher. Nível de significância: P0.05. RESULTADOS: O MES durante ritmo sinusal e BRE mostrou que os pacientes apresentavam prolongado TAV Global máximo e médio (138ms e 64,8ms, respectivamente) com significativa diferença Regional (54,5 x 56,4 x 95,9ms; p<0,0001; VD, septo e VE, respectivamente). A TRC reduziu o TAV Global máximo (138ms x 131ms; p=0,007) e o TAV Regional do VE (95,9 x 77,3ms; p=0,001). Houve aumento do TAV Regional do VD (54,5 x 78,9ms; p=0,001), sem alteração do TAV Regional do septo (56,4 x 59,6ms; p=ns). O comportamento do TAV Inter-Regional foi: Redução do TAV VE-VD (43,8 x 17,0ms; p=0,001) e do TAV septo-VE (42,6 x 16,3ms; p=0,001) e aumento do TAV septo-VD (6,9 x 16,0ms; p=0,002). CONCLUSÃO: O Mapeamento Eletrocardiográfico de Superfície possibilitou a caracterização detalhada da ativação elétrica ventricular de pacientes portadores de ressincronizador cardíaco através do comportamento elétrico global, regional e Inter-Regional durante ritmo sinusal com bloqueio de ramo esquerdo e estimulação biventricular / INTRODUCTION: The benefits of lower morbidity and mortality obtained with cardiac resynchronization therapy (CRT) in patients with heart failure are already well established. Invasive and noninvasive methods have been used to identify those who will really benefit from CRT, however 30% of these patients do not improve clinically/functionally. Few studies evaluated the cardiac electrical development of patients undergoing CRT. OBJECTIVE: To obtain through the body surface potential mapping (BSPM), a noninvasive approach, characterization of the ventricular electrical activation development in patients after CRT. METHODS: We studied 91 patients with heart failure and left bundle-branch block (LBBB) who underwent CRT, 36 of whom were excluded for AF (20), RBBB (3), hypertrophic (3) or congenital (1) cardiomyopathy, or depended upon a pacemaker before CRT (9). Mean age was 61±10 years, LVEF 0.28±0.9, QRSd 182±24ms, NYHA functional class III(78%) and IV(22%). All underwent BSPM examination of 87 simultaneous leads (58 on the anterior chest, 29 on the back) with the resynchronization device on, then in intrinsic rhythm and LBBB (device off). The BSPM isochronal maps provided maximal and mean global ventricular activation times (VAT) for all the 87 leads. From VATs thus obtained, separate mean values for the RV, septum and LV areas were then calculated. VAT differences between RV-LV, septum-RV and septum-LV, were analyzed and denominated inter-regional VATs. Mann-Whitney, Kruskall-Wallis and Fisher statistics were used, with P.05 established as the significance level. RESULTS: During sinus rhythm/LBBB the BSPM showed patients evidencing prolonged maximal and mean global VATs (138ms and 64.8ms, respectively), with significant regional differences (54.5 vs 56.4 vs 95.9ms; RV, septum and LV, respectively; p<0.0001). CRT reduced the maximal global VAT (138ms vs 131ms; p=0.007) and the LV regional VAT (95.9 vs 77.3ms; p=0.001). The RV regional VAT increased (54.5 vs 78.9ms; p=0.001), with no alteration of the septum regional VAT (56.4 vs 59.6ms; p=ns). The inter-regional VAT developed as follows: decrease in VATLV-RV (43.8 vs 17.0ms; p=0.001) and VATseptum-LV (42.6 vs 16.3ms; p=0.001), and increase in VATseptum-RV (6.9 vs 16.0ms; p=0.002). CONCLUSION: The body surface potential mapping permitted a detailed characterization of the ventricular electrical activation of patients carrying a cardiac resynchronization device, by mapping the global, regional and inter-regional electrical activation development during sinus rhythm with left bundle-branch block, and in biventricular pacing