Association of body composition and vitamin D levels with cardiac geometric pattern in rheumatoid arthritis patients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Insulin Resistance, Dyslipidemia and Cardiovascular Changes in a Group of Obese Children

Introduction: Obesity-related comorbidities are present in young obese children, providing a platform for early adult cardiovascular disorders. Objectives: To compare and correlate markers of adiposity to metabolic disturbances, vascular and cardiac morphology in a European pediatric obese cohort. Methods: We carried out an observational and transversal analysis in a cohort consisting of 121 obese children of both sexes, between the ages of 6 and 17 years. The control group consisted of 40 children with normal body mass index within the same age range. Markers of adiposity, plasma lipids and lipoproteins, homeostasis model assessment-insulin resistance, common carotid artery intima-media thickness and left ventricular diameters were analyzed. Results: There were statistically significant differences between the control and obese groups for the variables analyzed, all higher in the obese group, except for age, high-density lipoprotein cholesterol and adiponectin, higher in the control group. In the obese group, body mass index was directly correlated to left ventricular mass (r=0.542; p=0.001), the homeostasis model assessment-insulin resistance (r=0.378; p=<0.001) and mean common carotid artery intima-media thickness (r=0.378; p=<0.001). In that same group, insulin resistance was present in 38.1%, 12.5% had a combined dyslipidemic pattern, and eccentric hypertrophy was the most common left ventricular geometric pattern. Conclusions: These results suggest that these markers may be used in clinical practice to stratify cardiovascular risk, as well as to assess the impact of weight control programs.

Aplicação dos métodos gravimétrico e magnetométrico para a definição do comportamento estrutural da faixa de dobramentos Araguaia

O presente trabalho consiste na interpretação de informações gravimétricas e aeromagnetométricas (Projeto Geofísico Brasil-Canadá - PGBC) da região setentrional da Faixa de Dobramentos Araguaia, envolvendo uma área de aproximadamente 129.000km², compreendida entre os meridianos 47°50’W e 50°30’W e paralelos 4°50'S e 9°00'S. Abrange porções sudeste do Estado do Pará, noroeste de Goiás e oeste do Maranhão. Os trabalhos de campo constaram de levantamentos gravimétrico e altimétrico, ao longo de rodovias que constituem a rede viária regional, e os resultados obtidos, após correções e reduções, foram então organizados de forma a constituírem um mapa de anomalias Bouguer, apresentado em escala 1:500.000. O padrão gravimétrico da faixa de dobramentos Araguaia se caracteriza por mostrar feições predominantemente longitudinais, com curvas isoanômalas de direções submeridianas, concordante com o comportamento litológico-estrutural conhecido para a área. Na porção centro-meridional desse mapa aparece uma zona de anomalia negativa, alongada e intensa (menos de -100mgal), a qual sofre duas importantes inflexões para NW, sendo uma correlacionável ao Lineamento Carajás, e a outra na altura do paralelo 5°30'S. Apresenta zonas de altos gravimétricos, notadamente na porção noroeste (domínio cratônico), relacionada à influência das metavulcânicas do Grupo Grão Pará, e na porção nordeste, devida a massas densas introduzidas na crosta. Destaca-se também o relativo alto gravimétrico acompanhando o flanco oriental do eixo de ocorrência das braquidobras, podendo ser devido a massas excedentes colocadas sob essa região, através de esforços tectônicos, produzindo elevações do nível de base da crosta e consequentemente do embasamento. De forma genérica o flanco oriental da faixa mostra um gradiente mais intenso que o ocidental, devido principalmente à configuração geométrica das estruturas nesse setor. Da mesma forma merece destaque o gradiente regional ascendente de sul para norte. A análise das cartas de intensidade magnética do PGBC fornecem condições à individualização de diversos domínios magnéticos, perfeitamente correlacionáveis litológico e estruturalmente com as unidades geotectônicas que compõem o arcabouço regional, assim como suas subunidades. A execução de modelamento simples, quer para as informações gravimétricas como magnetométricas, objetivaram fornecer subsídios semi-quantitativos à interpretação, de forma a auxiliar no estabelecimento do padrão geométrico do embasamento da faixa de dobramentos Araguaia, assim como das estruturas a ela impostas. Assim, por meio do processamento das informações gravimétricas, verificou-se um padrão geométrico na forma de fatias imbricadas, estabelecidas sobre o substrato. A grande anomalia negativa da porção centro-meridional da faixa pode estar relacionada a uma deficiência de massa profunda (depressão na base da crosta) ou ainda a uma associação entre contraste de densidade e espessamento do pacote de supracrustais, nessa porção. O baixo gravimétrico da porção sudeste da área, entre Guarai e Tupirama, é devido a uma depressão do embasamento, da mesma forma como a anomalia negativa associada ao Lineamento Carajás está relacionada a uma estrutura sinformal conhecida.

Impacto do padrão geométrico ventricular na remodelação cardíaca após o infarto do miocárdio

BACKGROUND: The relevance of left ventricular (LV) geometric pattern after myocardial infarction is not known. OBJECTIVES: To analyze the presence of different LV geometric patterns and teir impact as a predictor of remodeling in patients with myocardial infarction. METHODS: Patients with anterior acute myocardial infarction (n = 80) were divided according to the geometric pattern: normal (normal left ventricular mass index [LVMI] and normal relative wall thickness [RWT]), concentric remodeling (normal LVMI and increased RWT), concentric hypertrophy (increased LVMI and RWT) and eccentric hypertrophy (increased LVMI and normal RWT). After six months, echocardiographic assessment was repeated. RESULTS: Four patients died. Of the survivors, 41 showed remodeling (R +), whereas 39 did not (R-). Considering the geometric pattern, the cases were distributed as follows: 24 patients with normal pattern, 13 with concentric remodeling, 29 with concentric hypertrophy and 14 with eccentric hypertrophy. Patients who showed remodeling had larger infarction sizes analyzed by peak CPK (R + = 4,610 (1,688-7,970), R- = 1,442 (775-4247), p <0.001) and CK-MB (R + = 441 (246 - 666), R- = 183 (101-465), p <0.001), trend towards higher prevalence of concentric remodeling (R+ = 10, R- = 3, p = 0.08) and lower prevalence of eccentric hypertrophy (R + = 2 R- = 12, p = 0.006). In the multivariate regression analysis, infarction size was a predictor (OR = 1.01, p = 0.020) and eccentric hypertrophy was a protective factor (OR = 0.189, p = 0.046) of ventricular remodeling after coronary occlusion. CONCLUSION: The LV geometric pattern of can have an impact on the remodeling process in patients with myocardial infarction.

Diseño de la sala 6 de Kinépolis (Madrid) con un sistema Dolby ATMOS

El objetivo de este Proyecto Fin de Carrera es el estudio y simulación de la sonorización de una sala de cine mediante la utilización del sistema DOLBY ATMOS. Para ello, se simulará la sala 6 del complejo de cines Kinépolis de Madrid utilizando el programa de simulación electroacústica EASE en el que se dispondrá el sistema de sonido DOLBY ATMOS. Primero se procederá a realizar el modelo geométrico en el programa EASE, a partir de los planos de la instalación y medidas realizadas en el recinto. Este programa de simulación permite obtener los parámetros acústicos y electroacústicos necesarios para realizar el estudio de la sala. Luego se diseñará el sistema de sonido de acuerdo a las disposiciones del sistema DOLBY ATMOS, mediante la ubicación de sistemas de altavoces de cine existentes en el mercado, siempre intentando mantener el uso de la sala de forma convencional como DOLBY DIGITAL y cumpliendo los requisitos de uniformidad y ángulos de apuntamiento recomendados por DOLBY. A continuación, una vez dispuestos los altavoces, se procederá a su configuración, realizando una ecualización y ajuste de nivel de manera individual para cada una de las fuentes sonoras, tanto de los altavoces de pantalla, altavoces de surround de pared y techo y los altavoces de subgraves. Como resultado de todo ello, se comprobarán parámetros como la inteligibilidad, respuesta impulsiva, respuesta en frecuencia y tiempo de reverberación en diferentes puntos de escucha, comparando los resultados obtenidos entre ellos. También se realizará una configuración compatible con el sistema de sonido 7.1, realizando su correspondiente configuración, ecualización, ajuste y aplicando los retardos necesarios. Una vez esté todo configurado, será dar un presupuesto de lo que supondría la reformar de un cine convencional a un sistema DOLBY ATMOS, teniendo en cuenta el número de altavoces disponibles en la sala actual, los modelos utilizados, amplificadores y mano de obra. También se realizará un diagrama de conexionado del sistema de sonido utilizado en el proyecto, incluyendo todos los parámetros necesarios de la configuración. Por último se comprobará la viabilidad técnica y económica del sistema diseñado, viendo cuál es la opción que más se adecua a cada necesidad y sugiriendo soluciones a los posibles problemas que se puedan encontrar. ABSTRACT. The main aim of this Project is the study and simulation of the sound of a movie theater by using DOLBY ATMOS system. It is going to be simulated the movie theatre 6 at Kinepolis cinema complex in Madrid using the simulation program EASE according to the sound system DOLBY ATMOS. First of all we proceed to conduct the geometric pattern in the EASE program, from installation drawings and measurements made on the premises. This simulation program allows getting the acoustic and electroacoustic parameters necessary for the study of the theatre. Then the sound system designed according to the suggestions of ATMOS DOLBY, by locating theater speaker systems on the market, always trying to keep the use of the room for DOLBY DIGITAL conventional and meeting the requirements of uniformity and pointing angles DOLBY recommended. Then, once the speakers are prepared, you can proceed to configure, make equalization and level setting individually for each of the sound sources, both screen speakers, surround speakers (wall and ceiling) and subwoofer. As a result, parameters are checked as intelligibility, impulse response, frequency response and reverberation time in different listening points, comparing the results between each other. There will also be configured to support 7.1 sound system, making the corresponding settings, equalization, level setting and applying the necessary delays. Once everything is configured, it will give an estimate of what would be the reform of a conventional film DOLBY ATMOS system, taking into account the number of speakers available in the current room, the models used, amplifiers and labor. Also there will be a wiring diagram of the sound system used in this project, including all of the configuration parameters needed. Finally, check the technical and economic feasibility of the designed system, seeing what is the option that best suits to each need and suggesting possible solutions to problems you might find during the process.

Characterization of rock joints by fractal analysis

From a physical perspective, a joint experiences fracturing processes that affect the rock at both microscopic and macroscopic levels. The result is a behaviour that follows a fractal structure. In the first place, for saw-tooth roughness profiles, the use of the triadic Koch curve appears to be adequate and by means of known correlations the JRC parameter is obtained from the angle measured on the basis of the height and length of the roughnesses. Therefore, JRC remains related to the geometric pattern that defines roughness by fractal analysis. In the second place, to characterise the geometry of irregularities with softened profiles, consequently, is proposed a characterisation of the fractal dimension of the joints with a circumference arc generator that is dependent on an average contact angle with regard to the mid-plane. The correlation between the JRC and the fractal dimension of the model is established with a defined statistical ratio.

Resonadores piezoeléctricos de cizalladura: estudio de la formación de biofilms y caracterización de fluidos magneto‐reológicos

La presente tesis revisa y analiza algunos aspectos fundamentales relativos al comportamiento de los sensores basados en resonadores piezoeléctricos TSM (Thickness Shear Mode), así como la aplicación de los mismos al estudio y caracterización de dos medios viscoelásticos de gran interés: los fluidos magnetoreológicos y los biofilms microbianos. El funcionamiento de estos sensores está basado en la medida de sus propiedades resonantes, las cuales varían al entrar en contacto con el material que se quiere analizar. Se ha realizado un análisis multifrecuencial, trabajando en varios modos de resonancia del transductor, en algunas aplicaciones incluso de forma simultánea (excitación pulsada). Se han revisado fenómenos como la presencia de microcontactos en la superficie del sensor y la resonancia de capas viscoelásticas de espesor finito, que pueden afectar a los sensores de cuarzo de manera contraria a lo que predice la teoría convencional (Sauerbrey y Kanazawa), pudiéndonos llevar a incrementos positivos de la frecuencia de resonancia. Además, se ha estudiado el efecto de una deposición no uniforme sobre el resonador piezoeléctrico. Para ello se han medido deposiciones de poliuretano, modelándose la respuesta del resonador con estas deposiciones mediante FEM. El modelo numérico permite estudiar el comportamiento del resonador al modificar distintas variables geométricas (espesor, superficie, no uniformidad y zona de deposición) de la capa depositada. Se ha demostrado que para espesores de entre un cuarto y media longitud de onda aproximadamente, una capa viscoelástica no uniforme sobre la superficie del sensor, amplifica el incremento positivo del desplazamiento de la frecuencia de resonancia en relación con una capa uniforme. Se ha analizado también el patrón geométrico de la sensibilidad del sensor, siendo también no uniforme sobre su superficie. Se han aplicado sensores TSM para estudiar los cambios viscoelásticos que se producen en varios fluidos magneto-reológicos (FMR) al aplicarles distintos esfuerzos de cizalla controlados por un reómetro. Se ha podido ver que existe una relación directa entre diversos parámetros reológicos obtenidos con el reómetro (fuerza normal, G’, G’’, velocidad de deformación, esfuerzo de cizalla…) y los parámetros acústicos, caracterizándose los FMR tanto en ausencia de campo magnético, como con campo magnético aplicado a distintas intensidades. Se han estudiado las ventajas que aporta esta técnica de medida sobre la técnica basada en un reómetro comercial, destacando que se consigue caracterizar con mayor detalle algunos aspectos relevantes del fluido como son la deposición de partículas (estabilidad del fluido), el proceso de ruptura de las estructuras formadas en los FMR tanto en presencia como en ausencia de campo magnético y la rigidez de los microcontactos que aparecen entre partículas y superficies. También se han utilizado sensores de cuarzo para monitorear en tiempo real la formación de biofilms de Staphylococcus epidermidis y Eschericia coli sobre los propios resonadores de cristal de cuarzo sin ningún tipo de recubrimiento, realizándose ensayos con cepas que presentan distinta capacidad de producir biofilm. Se mostró que, una vez que se ha producido una primera adhesión homogénea de las bacterias al sustrato, podemos considerar el biofilm como una capa semi-infinita, de la cual el sensor de cuarzo refleja las propiedades viscoelásticas de la región inmediatamente contigua al resonador, no siendo sensible a lo que sucede en estratos superiores del biofilm. Los experimentos han permitido caracterizar el módulo de rigidez complejo de los biofilms a varias frecuencias, mostrándose que el parámetro característico que indica la adhesión de un biofilm tanto en el caso de S. epidermidis como de E. coli, es el incremento de G’ (relacionado con la elasticidad o rigidez de la capa), el cual viene ligado a un incremento de la frecuencia de resonancia del sensor. ABSTRACT This thesis reviews and analyzes some key aspects of the behavior of sensors based on piezoelectric resonators TSM (Thickness Shear Mode) and their applications to the study and characterization in two viscoelastic media of great interest: magnetorheological fluids and microbial biofilms. The operation of these sensors is based on the analysis of their resonant properties that vary in contact with the material to be analyzed. We have made a multi-frequency analysis, working in several modes of resonance of the transducer, in some applications even simultaneously (by impulse excitation). We reviewed some phenomena as the presence of micro-contacts on the sensor surface and the resonance of viscoelastic layers of finite thickness, which can affect quartz sensors contrary to the conventional theory predictions (Sauerbrey and Kanazawa), leading to positive resonant frequency shifts. In addition, we studied the effect of non-uniform deposition on the piezoelectric resonator. Polyurethane stools have been measured, being the resonator response to these depositions modeled by FEM. The numerical model allows studying the behavior of the resonator when different geometric variables (thickness, surface non-uniformity and deposition zone) of the deposited layer are modified. It has been shown that for thicknesses between a quarter and a half of a wavelength approximately, non-uniform deposits on the sensor surface amplify the positive increase of the resonance frequency displacement compared to a uniform layer. The geometric pattern of the sensor sensitivity was also analyzed, being also non-uniform over its surface. TSM sensors have been applied to study the viscoelastic changes occurring in various magneto-rheological fluids (FMR) when subjected to different controlled shear stresses driven by a rheometer. It has been seen that there is a direct relationship between various rheological parameters obtained with the rheometer (normal force, G', G'', stress, shear rate ...) and the acoustic parameters, being the FMR characterized both in the absence of magnetic field, and when the magnetic field was applied at different intensities. We have studied the advantages of this technique over the characterization methods based on commercial rheometers, noting that TSM sensors are more sensitive to some relevant aspects of the fluid as the deposition of particles (fluid stability), the breaking process of the structures formed in the FMR both in the presence and absence of magnetic field, and the rigidity of the micro-contacts appearing between particles and surfaces. TSM sensors have also been used to monitor in real time the formation of biofilms of Staphylococcus epidermidis and Escherichia coli on the quartz crystal resonators themselves without any coating, performing tests with strains having different ability to produce biofilm. It was shown that, once a first homogeneous adhesion of bacteria was produced on the substrate, the biofilm can be considered as a semi-infinite layer and the quartz sensor reflects only the viscoelastic properties of the region immediately adjacent to the resonator, not being sensitive to what is happening in upper layers of the biofilm. The experiments allow the evaluation of the biofilm complex stiffness module at various frequencies, showing that the characteristic parameter that indicates the adhesion of a biofilm for the case of both S. epidermidis and E. coli, is an increased G' (related to the elasticity or stiffness of the layer), which is linked to an increase in the resonance frequency of the sensor.

Is quantitative interpretation likely to increase sensitivity of dobutamine stress echocardiography? A study of false-negative results

Background: False-negative interpretations of do-butamine stress echocardiography (DSE) may be associated with reduced wall stress. using measurements of contraction, we sought whether these segments were actually ischemic but unrecognized or showed normal contraction. Methods. We studied 48 patients (29 men; mean age 60 +/- 10 years) with normal regional function on the basis of standard qualitative interpretation of DSE. At coronary angiography within. 6 months of DSE, 32 were identified as having true-negative and 16 as having false-negative results of DSE. Three apical views were used to measure regional function with color Doppler tissue, integrated backscatter, and strain rate imaging. Cyclic variation of integrated backscatter was measured in 16 segments, and strain rate and peak systolic strain was calculated in 6 walls at rest and peak stress. Results. Segments with false-negative results of DSE were divided into 2 groups with and without low wall stress according to previously published cut-off values. Age, sex, left ventricular mass, left ventricular geometric pattern, and peak workload were not significantly different between patients with true and false-negative results of DSE. Importantly, no significant differences in cyclic variation and strain parameters at rest and peak stress were found among segments with true-and false-negative results of DSE with and without low wall stress. Stenosis severity had no influence on cyclic variation and strain parameters at peak stress. Conclusions: False-negative results of DSE reflect lack of ischemia rather than underinterpretation of regional left ventricular function. Quantitative markers are unlikely to increase the sensitivity of DSE.

Diastolic dysfunction is a manifestation of ventricular-vascular interaction in patients with type 2 diabetes mellitus

Vascular disease is accelerated in patients with Type 2 diabetes mellitus (T2DM). Since the systemic vasculature plays a pivotal role in myocardial loading, this study aimed to determine the effect of arterial characteristics on left ventricular (LV) morphology and function in patients with T2DM. Conventional echocardiography and tissue Doppler imaging were performed in 172 T2DM patients (95 men; aged 55±11y) with preserved ejection fraction (62±5%). Patients were stratified into groups based on LV geometric pattern (normal [n = 79], concentric remodeling [n = 33], concentric hypertrophy [n = 29], eccentric hypertrophy [n = 31]). Total arterial compliance (TAC) was recorded by simultaneous radial tonometry and aortic outflow pulsed wave Doppler. Arterial (brachial and carotid) structure and function were determined by standard ultrasound methods. There were no significant differences between the LV geometric groups in demographic or clinical parameters. The concentric hypertrophy group had significantly increased carotid artery diameter (6.0±0.7mm versus 6.5±0.7mm; p < 0.05) and stiffness (1912±1203 dynes/cm2mm versus 2976±2695 dynes/cm2mm×10−6; p < 0.05) compared to those with normal geometry. However, TAC did not differ between groups. LV diastolic function, as determined by the ratio of diastolic mitral inflow velocity to mitral annulus tissue velocity (E/E_), was significantly associated with carotid artery relative wall thickness and intima media thickness (p < 0.05). Moreover, E/E_ was independently predicted by carotid artery relative wall thickness (β = 22.9; p = 0.007). We conclude that structural characteristics of the carotid artery are associated with abnormal LV structure and function in patients with T2DM. The LV functional irregularities may be a downstream consequence of amplified pressure wave reflections effecting sub-optimal ventricular-vascular interaction.

Patterns in the lottery game

The present study is based on the analysis and results of a close to 5 years’ study in the frame which we used a “Lottery Game” in the "Decision Making Skills" subject taught at Corvinus Business School, Corvinus University of Budapest. In the frame of the "game", the students (Hungarians (n=231) and foreigners (n=267) alike) have to mark 6 numbers on a 7x7 lottery ticket. The winner is the student whose numbers differ the most from those of all the other students’. Upon analyzing the results (irrespectively of nationality) the authors have noted something notable: the winning combinations - rather than being located randomly on the ticket, characteristically resemble a geometric form. In our study we wanted to detect the relevance of geometry in this kind of choices. It is hypothesized that in such games (lottery type, related to numeric combination choice), where the players decide upon their strategy (choice of numbers) by also taking into consideration others’ expected choices, the winning strategy is characteristically some consciously chosen scheme or pattern as opposed to a random one. The study presents the results of the available samples (Hungarian students: n=231, foreign students: n=267), the winning combinations, the most often designated numbers, as well as the least “popular” numbers and their presentation on a "heat map". In the case of the majority of the winning tickets we found the use of conscious strategic choice to be more useful. These conscious strategic decisions were reflected in identifiable geometric forms. Based on the results, we hypothesize that in the "hidden lottery" game – in contrast with random choice – the most effective strategy of choice is the conscious ordered one in which the player marks the numbers on the lottery ticket in some modified geometric pattern. The goal of the paper is to propose further research on the field.

Refractive and geometric lens characterization through multi-wavelength digital speckle pattern interferometry

Physical parameters of different types of lenses were measured through digital speckle pattern interferometry (DSPI) using a multimode diode laser as light source. When such lasers emit two or more longitudinal modes simultaneously the speckle image of an object appears covered of contour fringes. By performing the quantitative fringe evaluation the radii of curvature as well as the refractive indexes of the lenses were determined. The fringe quantitative evaluation was carried out through the four- and the eight-stepping techniques and the branch-cut method was employed for phase unwrapping. With all these parameters the focal length was calculated. This whole-field multi-wavelength method does enable the characterization of spherical and aspherical lenses and of positive and negative ones as well. (C) 2007 Elsevier B.V. All rights reserved.

Geometric constraints explain much of the species richness pattern in African birds

The world contains boundaries (e.g., continental edge for terrestrial taxa) that impose geometric constraints on the distribution of species ranges. Thus, contrary to traditional thinking, the expected species richness pattern in absence of ecological or physiographical factors is unlikely to be uniform. Species richness has been shown to peak in the middle of a bounded one-dimensional domain, even in the absence of ecological or physiographical factors. Because species ranges are not linear, an extension of the approach to two dimensions is necessary. Here we present a two-dimensional null model accounting for effects of geometric constraints. We use the model to examine the effects of continental edge on the distribution of terrestrial animals in Africa and compare the predictions with the observed pattern of species richness in birds endemic to the continent. Latitudinal, longitudinal, and two-dimensional patterns of species richness are predicted well from the modeled null effects alone. As expected, null effects are of high significance for wide ranging species only. Our results highlight the conceptual significance of an until recently neglected constraint from continental shape alone and support a more cautious analysis of species richness patterns at this scale.

Modeling and simulating a mathematical tool for multi-robot pattern transformation

The work reported in this paper is motivated by the need to investigate general methods for pattern transformation. A formal definition for pattern transformation is provided and four special cases namely, elementary and geometric transformation based on repositioning all and some agents in the pattern are introduced. The need for a mathematical tool and simulations for visualizing the behavior of a transformation method is highlighted. A mathematical method based on the Moebius transformation is proposed. The transformation method involves discretization of events for planning paths of individual robots in a pattern. Simulations on a particle physics simulator are used to validate the feasibility of the proposed method.

A swarm pattern transformation method based on macroscopic parameter operations

The work reported in this paper is motivated by biomimetic inspiration - the transformation of patterns. The major issue addressed is the development of feasible methods for transformation based on a macroscopic tool. The general requirement for the feasibility of the transformation method is determined by classifying pattern formation approaches an their characteristics. A formal definition for pattern transformation is provided and four special cases namely, elementary and geometric transformation based on repositioning all and some robotic agents are introduced. A feasible method for transforming patterns geometrically, based on the macroscopic parameter operation of a swarm is considered. The transformation method is applied to a swarm model which lends itself to the transformation technique. Simulation studies are developed to validate the feasibility of the approach, and do indeed confirm the approach.

Modeling and simulating a mathematical tool for multi-robot pattern transformation

The work reported in this paper is motivated by the need to investigate general methods for pattern transformation. A formal definition for pattern transformation is provided and four special cases namely, elementary and geometric transformation based on repositioning all and some agents in the pattern are introduced. The need for a mathematical tool and simulations for visualizing the behavior of a transformation method is highlighted. A mathematical method based on the Moebius transformation is proposed. The transformation method involves discretization of events for planning paths of individual robots in a pattern. Simulations on a particle physics simulator are used to validate the feasibility of the proposed method.