Heterogeneous Multi-Robot Cooperation

This report addresses the problem of achieving cooperation within small- to medium- sized teams of heterogeneous mobile robots. I describe a software architecture I have developed, called ALLIANCE, that facilitates robust, fault tolerant, reliable, and adaptive cooperative control. In addition, an extended version of ALLIANCE, called L-ALLIANCE, is described, which incorporates a dynamic parameter update mechanism that allows teams of mobile robots to improve the efficiency of their mission performance through learning. A number of experimental results of implementing these architectures on both physical and simulated mobile robot teams are described. In addition, this report presents the results of studies of a number of issues in mobile robot cooperation, including fault tolerant cooperative control, adaptive action selection, distributed control, robot awareness of team member actions, improving efficiency through learning, inter-robot communication, action recognition, and local versus global control.

Safe Distributed Coordination of Heterogeneous Robots through Dynamic Simple Temporal Networks

Research on autonomous intelligent systems has focused on how robots can robustly carry out missions in uncertain and harsh environments with very little or no human intervention. Robotic execution languages such as RAPs, ESL, and TDL improve robustness by managing functionally redundant procedures for achieving goals. The model-based programming approach extends this by guaranteeing correctness of execution through pre-planning of non-deterministic timed threads of activities. Executing model-based programs effectively on distributed autonomous platforms requires distributing this pre-planning process. This thesis presents a distributed planner for modelbased programs whose planning and execution is distributed among agents with widely varying levels of processor power and memory resources. We make two key contributions. First, we reformulate a model-based program, which describes cooperative activities, into a hierarchical dynamic simple temporal network. This enables efficient distributed coordination of robots and supports deployment on heterogeneous robots. Second, we introduce a distributed temporal planner, called DTP, which solves hierarchical dynamic simple temporal networks with the assistance of the distributed Bellman-Ford shortest path algorithm. The implementation of DTP has been demonstrated successfully on a wide range of randomly generated examples and on a pursuer-evader challenge problem in simulation.

Context Interchange as a Scalable Solution to Interoperating Amongst Heterogeneous Dynamic Services

Many online services access a large number of autonomous data sources and at the same time need to meet different user requirements. It is essential for these services to achieve semantic interoperability among these information exchange entities. In the presence of an increasing number of proprietary business processes, heterogeneous data standards, and diverse user requirements, it is critical that the services are implemented using adaptable, extensible, and scalable technology. The COntext INterchange (COIN) approach, inspired by similar goals of the Semantic Web, provides a robust solution. In this paper, we describe how COIN can be used to implement dynamic online services where semantic differences are reconciled on the fly. We show that COIN is flexible and scalable by comparing it with several conventional approaches. With a given ontology, the number of conversions in COIN is quadratic to the semantic aspect that has the largest number of distinctions. These semantic aspects are modeled as modifiers in a conceptual ontology; in most cases the number of conversions is linear with the number of modifiers, which is significantly smaller than traditional hard-wiring middleware approach where the number of conversion programs is quadratic to the number of sources and data receivers. In the example scenario in the paper, the COIN approach needs only 5 conversions to be defined while traditional approaches require 20,000 to 100 million. COIN achieves this scalability by automatically composing all the comprehensive conversions from a small number of declaratively defined sub-conversions.

Plasma polymerization of C[subscript 4]F[subscript 8] thin film on high aspect ratio silicon molds

High aspect ratio polymeric micro-patterns are ubiquitous in many fields ranging from sensors, actuators, optics, fluidics and medical. Second generation PDMS molds are replicated against first generation silicon molds created by deep reactive ion etching. In order to ensure successful demolding, the silicon molds are coated with a thin layer of C[subscript 4]F[subscript 8] plasma polymer to reduce the adhesion force. Peel force and demolding status are used to determine if delamination is successful. Response surface method is employed to provide insights on how changes in coil power, passivating time and gas flow conditions affect plasma polymerization of C[subscript 4]F[subscript 8].

Learning and adaptation in physical heterogeneous teams of robots

In this paper we present a novel approach to assigning roles to robots in a team of physical heterogeneous robots. Its members compete for these roles and get rewards for them. The rewards are used to determine each agent’s preferences and which agents are better adapted to the environment. These aspects are included in the decision making process. Agent interactions are modelled using the concept of an ecosystem in which each robot is a species, resulting in emergent behaviour of the whole set of agents. One of the most important features of this approach is its high adaptability. Unlike some other learning techniques, this approach does not need to start a whole exploitation process when the environment changes. All this is exemplified by means of experiments run on a simulator. In addition, the algorithm developed was applied as applied to several teams of robots in order to analyse the impact of heterogeneity in these systems

Resource dimensioning aspect of heterogeneous traffic with different service requirements: Integration versus segregation

In this paper, we consider the ATM networks in which the virtual path concept is implemented. The question of how to multiplex two or more diverse traffic classes while providing different quality of service requirements is a very complicated open problem. Two distinct options are available: integration and segregation. In an integration approach all the traffic from different connections are multiplexed onto one VP. This implies that the most restrictive QOS requirements must be applied to all services. Therefore, link utilization will be decreased because unnecessarily stringent QOS is provided to all connections. With the segregation approach the problem can be much simplified if different types of traffic are separated by assigning a VP with dedicated resources (buffers and links). Therefore, resources may not be efficiently utilized because no sharing of bandwidth can take place across the VP. The probability that the bandwidth required by the accepted connections exceeds the capacity of the link is evaluated with the probability of congestion (PC). Since the PC can be expressed as the CLP, we shall simply carry out bandwidth allocation using the PC. We first focus on the influence of some parameters (CLP, bit rate and burstiness) on the capacity required by a VP supporting a single traffic class using the new convolution approach. Numerical results are presented both to compare the required capacity and to observe which conditions under each approach are preferred

Large heterogeneous classes. 'Clases heterog??neas'

El art??culo es un resumen de la propia autora sobre la conferencia realizada en la sede del CDL. Contiene una presentaci??n en catal??n, realizada por Aina Carreras

[177Lu – DOTA – Tyr3] – OCTREOTATE para el tratamiento de tumores neuroendocrinos gastroenteropancreáticos. Revisión sistemática de la literatura.

Introducción: los tumores neuroendocrinos gastroenteropancreáticos se diagnostican en estadio avanzado en 60 - 80% de los pacientes y las opciones terapéuticas son limitadas. Se realizó una revisión sobre el beneficio clínico del tratamiento con [177Lu - DOTA - Tyr3] - Octreotate en pacientes con enfermedad metastásica o inoperable. Objetivos: evaluar la eficacia, impacto en calidad de vida y toxicidad de la terapia con 177Lu DOTATE en pacientes con tumores neuroendocrinos gastroenteropancreáticos avanzados. Materiales y Métodos: se condujo una revisión sistemática de la literatura mediante la búsqueda de estudios clínicos prospectivos y retrospectivos en bases electrónicas (MEDLINE, EMBASE, LILACS, SCIELO, OVID y la Biblioteca Cochrane) de cualquier idioma, año y estado de publicación. Se incluyeron 5 estudios, por la heterogeneidad existente entre los estudios no se realizó un metaanálisis. Resultados: la respuesta tumoral global fue del 45 - 57%, la enfermedad permaneció estable en 27% - 38% y progresó en 6% - 21% de casos en las series incluidas. El tiempo libre de progresión osciló entre 31 - 40 meses y la sobrevida global de 31– 51 meses. Se observó toxicidad hematológica grado 3-4 hasta en 9.5% de pacientes. Hubo mejoría significativa en la calidad de vida de pacientes tratados con 177LuDOTATATE. Conclusiones: la terapia con 177Lu- DOTATATE ofrece un beneficio clínico a los pacientes con tumores neuroendocrinos bien diferenciados avanzados por su impacto positivo en calidad de vida, control de síntomas, ralentiza la progresión tumoral y su toxicidad es baja.

Plasmodium vivax lineages: geographical distribution, tandem repeat polymorphism, and phylogenetic relationship

Background: Multi-drug resistance and severe/ complicated cases are the emerging phenotypes of vivax malaria, which may deteriorate current anti-malarial control measures. The emergence of these phenotypes could be associated with either of the two Plasmodium vivax lineages. The two lineages had been categorized as Old World and New World, based on geographical sub-division and genetic and phenotypical markers. This study revisited the lineage hypothesis of P. vivax by typing the distribution of lineages among global isolates and evaluated their genetic relatedness using a panel of new mini-satellite markers. Methods: 18S SSU rRNA S-type gene was amplified from 420 Plasmodium vivax field isolates collected from different geographical regions of India, Thailand and Colombia as well as four strains each of P. vivax originating from Nicaragua, Panama, Thailand (Pak Chang), and Vietnam (ONG). A mini-satellite marker panel was then developed to understand the population genetic parameters and tested on a sample subset of both lineages. Results: 18S SSU rRNA S-type gene typing revealed the distribution of both lineages (Old World and New World) in all geographical regions. However, distribution of Plasmodium vivax lineages was highly variable in every geographical region. The lack of geographical sub-division between lineages suggests that both lineages are globally distributed. Ten mini-satellites were scanned from the P. vivax genome sequence; these tandem repeats were located in eight of the chromosomes. Mini-satellites revealed substantial allelic diversity (7-21, AE = 14.6 +/- 2.0) and heterozygosity (He = 0.697-0.924, AE = 0.857 +/- 0.033) per locus. Mini-satellite comparison between the two lineages revealed high but similar pattern of genetic diversity, allele frequency, and high degree of allele sharing. A Neighbour-Joining phylogenetic tree derived from genetic distance data obtained from ten mini-satellites also placed both lineages together in every cluster. Conclusions: The global lineage distribution, lack of genetic distance, similar pattern of genetic diversity, and allele sharing strongly suggested that both lineages are a single species and thus new emerging phenotypes associated with vivax malaria could not be clearly classified as belonging to a particular lineage on basis of their geographical origin.

Loss of nerve fiber layer in HIV positive patients and comparative patterns in a series of cases in Bucaramanga, Colombia

Objective: The objective of this study is to conduct a description of the features of optic neuropathy associated with Human Immunodeficiency Virus in relation to their possible incidence within our population, regarding that there is no data in our population in terms of frequency of this pathology (1,2). Methodology: Descriptive cross-sectional study of a clinical series of patients infected with human immunodeficiency virus, but AIDS, and the thickness of optic nerve´s layer of fibers studied with OCT technology (optical coherence tomography), patients were cited once captured. OCT was performed by the same observer, by taking 3 shots and picking the one with better reliability. Patients were given personally to the Ophthalmologic Foundation of Santander to conduct the review called OCT (optical coherence tomography). Results: In terms of viral load variable, we found a clear correlation in which validates the hypothesis that lower viral load means a thicker layer of fibers finding statistically significant differences for the 6 hours in right eye and 12 and 6 hours in left eye. Comparison between the known nomogram of fiber layer thickness for the population of Bucaramanga, Santander and thickness found in our sample, we note a clear decrease in the upper and lower quadrants, specifically in 7 hours and 11 hours, being more important in 7 hours, showing statistically significant differences. Conclusions: The pattern  of thinning of the nerve fiber layer in HIV positive patients without AIDS, and antiretroviral treatment type HAART, showed a statistically significant thinning targeted at 7 hours and 11 hours, being higher in first. Viral load figures have a direct relation with loss fiber layer, showing a statistically significant difference for the 6 and 12 hours.

Tandem Learning Plus : un proyecto europeo en Toledo.

Se trata de un intento de acercar al alumno al estudio del idioma extranjero a través del intercambio de alumnos entre Toledo y Belfast, se trata la necesidad de la práctica del idioma entre alumnos de los diferentes centros como medio de asentar los conocimientos del idioma. Se concluye con la reflexión de las ventajas del intercambio cultural .

A Monte Carlo-Based Fiber Tracking Algorithm using Diffusion Tensor MRI

Diffusion tensor magnetic resonance imaging, which measures directional information of water diffusion in the brain, has emerged as a powerful tool for human brain studies. In this paper, we introduce a new Monte Carlo-based fiber tracking approach to estimate brain connectivity. One of the main characteristics of this approach is that all parameters of the algorithm are automatically determined at each point using the entropy of the eigenvalues of the diffusion tensor. Experimental results show the good performance of the proposed approach

Nous complexos mono- i dinuclears de ruteni amb lligands polipiridílics i de tipus fosfina. Síntesi, caracterització i aplicacions catalítiques

La Tesi descriu de manera completa una sèrie de complexos de ruteni amb lligands polipiridílics i lligands auxiliars de tipus fosfina, dmso, nitril o aquo. Es descriuen estudis d'isomerització (cis/trans o coordinació meridional/facial) en complexos mononuclears, a partir de tècniques espectroscòpiques. Els resultats experimentals es corroboren a partir de càlculs DFT. S'han fet també estudis d'activitat catalítica en transferència d'hidrogen per als complexos Ru-fosfina. S'han sintetitzat també complexos dinuclears de ruteni amb el lligand tetradentat Hbpp i s'ha avaluat llur activitat en la catàlisi d'oxidació d'aigua, determinant la importància de la correcta orientació relativa dels centres actius Ru=O. L'heterogeneïtzació dels complexos sobre suports conductors permet avaluar llur activitat en fase heterogènia, millorant respecte el corresponent procés en dissolució. La co-polimerització dels catalitzadors amb espècies de tipus metalocarborà, amb major dilució del catalitzador i minimització de la sobreoxidació, millora notablement els resultats, permetent diverses reutilitzacions.