Hybrid coordination of reinforcement learning-based behaviors for AUV control

This paper proposes a hybrid coordination method for behavior-based control architectures. The hybrid method takes advantages of the robustness and modularity in competitive approaches as well as optimized trajectories in cooperative ones. This paper shows the feasibility of applying this hybrid method with a 3D-navigation to an autonomous underwater vehicle (AUV). The behaviors are learnt online by means of reinforcement learning. A continuous Q-learning implemented with a feed-forward neural network is employed. Realistic simulations were carried out. The results obtained show the good performance of the hybrid method on behavior coordination as well as the convergence of the behaviors

Efficient learning of reactive robot behaviors with a Neural-Q_learning approach

The purpose of this paper is to propose a Neural-Q_learning approach designed for online learning of simple and reactive robot behaviors. In this approach, the Q_function is generalized by a multi-layer neural network allowing the use of continuous states and actions. The algorithm uses a database of the most recent learning samples to accelerate and guarantee the convergence. Each Neural-Q_learning function represents an independent, reactive and adaptive behavior which maps sensorial states to robot control actions. A group of these behaviors constitutes a reactive control scheme designed to fulfill simple missions. The paper centers on the description of the Neural-Q_learning based behaviors showing their performance with an underwater robot in a target following task. Real experiments demonstrate the convergence and stability of the learning system, pointing out its suitability for online robot learning. Advantages and limitations are discussed

Assessing the link between coping patterns and interpersonal behaviors in depressed women

Aim. Stressful life events are an important contributor to the onset and course of depression. Coping strategies and interpersonal patterns have been found to mediate the effects of stress [1]. Methods. This study examined the relationship between coping patterns and interpersonal interactions in early psychotherapy sessions of 25 female patients with major depression. Transcripts were rated for coping patterns using the Coping Patterns Rating Scale (CPRS; [2]). Interpersonal patterns were assessed using the Structural Analysis of Social Behavior (SASB; [3]). Results. Significant correlations were found between coping patterns and markers of interpersonal functioning in selected contexts. Discussion. The implications of these findings in understanding an important aspect of vulnerability to depression and enhancing treatment outcome are discussed.

Eosinophilic meningitis caused by Angiostrongylus cantonensis: an emergent disease in Brazil

Eosinophilic meningitis (EoM) is an acute disease that affects the central nervous system. It is primarily caused by infection with the nematode Angiostrongylus cantonensis. This infection was previously restricted to certain Asian countries and the Pacific Islands, but it was first reported in Brazil in 2007. Since then, intermediate and definitive hosts infected with A. cantonensis have been identified within the urban areas of many states in Brazil, including those in the northern, northeastern, southeastern and southern regions. The goals of this review are to draw the attention of the medical community and health centres to the emergence of EoM in Brazil, to compile information about several aspects of the human infection and mode of transmission and to provide a short protocol of procedures for the diagnosis of this disease.

The role of hypocretin in driving arousal and goal-oriented behaviors.

The hypocretins (Hcrts), also called orexins, are two neuropeptides secreted by a few thousand neurons restricted to the lateral hypothalamus. The Hcrt peptides bind to two receptors located in nuclei associated with diverse cognitive and physiological functions. Experimental evidence has demonstrated that the physiological roles of hypocretins extend far beyond its initial role in food consumption and has emerged as a key system in the fields of sleep disorders and drug addiction. Here, we discuss recent evidence demonstrating a key role of hypocretin in the motivation for reward seeking in general, and drug taking in particular, and we delineate a physiological framework for this peptidergic system in orchestrating the appropriate levels of alertness required for the elaboration and the execution of goal-oriented behaviors. We propose a general role for hypocretins in mediating arousal, especially when an organism must respond to unexpected stressors and environmental challenges, which serve to shape survival behaviors. We also discuss the limit of the current experimental paradigms to address the question of how a system normally involved in the regulation of vigilance states and hyperarousal may promote a pathological state that elicits compulsive craving and relapse to drug seeking.

Influence on screening performance of second reading strategies in two lowvolume programs

BACKGROUND: The European Guidelines specify a minimum of 5,000 screening cases to be read yearly by radiologists carrying out second reading in non-centralized programs. This professional requirement is difficult to reach and/or to implement in regional programs covering a sparse population with a high number of participating radiology units, so that alternative blind double reading strategies must be devised. OBJECTIVE: To evaluate the effect on breast cancer screening performances of two second reading strategies used in non-centralized, low-volume programs. METHODS: Reading performances in two Swiss regional breast cancer screening programs (cantons of Wallis and Vaud), covering female populations, aged 50-69, of about 31'000 and 72'000 inhabitants were computed and compared. Both programs had similar screening regimens and organizations, but differed with respect to second reading. One setting applied a selective strategy whereby only experienced radiologists performed second reading; the other elicited not to restrict second readers on the basis of their individual screening activity. Analysis included some 140,000 mammograms performed between 1999 and 2005. RESULTS: Overall, screening performances improved with increasing total volume of reading, albeit not in a linear fashion. Regardless of setting, radiologists attained a higher level of screening accuracy when performing second rather than first readings, and incident rather than prevalent screening cases. The effect of a selective, small group of second readers appeared to impact favorably on the false-positive rate and other indicators of screening quality. As the learning curve depends on the number of mammograms read, these distinct strategies may bear different outcome in the long run. Implications and practical issues for low-volume programs are discussed.

Clustering of risk behaviors with cigarette consumption: a population-based survey.

OBJECTIVE: This study assessed clustering of multiple risk behaviors (i.e., low leisure-time physical activity, low fruits/vegetables intake, and high alcohol consumption) with level of cigarette consumption. METHODS: Data from the 2002 Swiss Health Survey, a population-based cross-sectional telephone survey assessing health and self-reported risk behaviors, were used. 18,005 subjects (8052 men and 9953 women) aged 25 years old or more participated. RESULTS: Smokers more frequently had low leisure time physical activity, low fruits/vegetables intake, and high alcohol consumption than non- and ex-smokers. Frequency of each risk behavior increased steadily with cigarette consumption. Clustering of risk behaviors increased with cigarette consumption in both men and women. For men, the odds ratios of multiple (> or =2) risk behaviors other than smoking, adjusted for age, nationality, and educational level, were 1.14 (95% confidence interval: 0.97, 1.33) for ex-smokers, 1.24 (0.93, 1.64) for light smokers (1-9 cigarettes/day), 1.72 (1.36, 2.17) for moderate smokers (10-19 cigarettes/day), and 3.07 (2.59, 3.64) for heavy smokers (> or =20 cigarettes/day) versus non-smokers. Similar odds ratios were found for women for corresponding groups, i.e., 1.01 (0.86, 1.19), 1.26 (1.00, 1.58), 1.62 (1.33, 1.98), and 2.75 (2.30, 3.29). CONCLUSIONS: Counseling and intervention with smokers should take into account the strong clustering of risk behaviors with level of cigarette consumption.

Space-time relatedness and Hamilton's rule for long-lasting behaviors in viscous populations.

Genes affect not only the behavior and fitness of their carriers but also that of other individuals. According to Hamilton's rule, whether a mutant gene will spread in the gene pool depends on the effects of its carrier on the fitness of all individuals in the population, each weighted by its relatedness to the carrier. However, social behaviors may affect not only recipients living in the generation of the actor but also individuals living in subsequent generations. In this note, I evaluate space-time relatedness coefficients for localized dispersal. These relatedness coefficients weight the selection pressures on long-lasting behaviors, which stem from a multigenerational gap between phenotypic expression by actors and the resulting environmental feedback on the fitness of recipients. Explicit values of space-time relatedness coefficients reveal that they can be surprisingly large for typical dispersal rates, even for hundreds of generations in the future.

Traduir i interpretar les llengües de la immigració a Catalunya: cap a la formació i acreditació d’un perfil professional emergent

El projecte que sol•licitem és el resultat natural d’una recerca iniciada l’any 2008 pel grup de recerca MIRAS (Mediació i Interpretació: Recerca en l’Àmbit Social) de la Universitat Autònoma de Barcelona. La recerca del grup MIRAS ha tingut com a objectiu general, durant els darrers dos anys, la definició del perfil professional del traductor/intèrpret als serveis públics. Aquesta figura emergent i encara poc reconeguda al nostre país va començar a sorgir a partir del boom migratori de les darreres dècades a Catalunya com a resposta als problemes de comunicació freqüents entre la població nouvinguda i els serveis públics locals. Per a assolir l’objectiu esmentat, la primera fase de la recerca del grup MIRAS s’ha centrat en el disseny, distribució, buidatge, anàlisi i creuament de dades de 250 qüestionaris semioberts dirigits als tres principals agents implicats en la interacció comunicativa que estudiem: els traductors/intèrprets, els usuaris i els proveïdors dels serveis. Els resultats d’aquest estudi han demostrat, entre d’altres qüestions rellevants, la manca d’una formació específica per als traductors/intèrprets als serveis públics, així com una absència de regulació de la professió que aquests exerceixen. Un cop realitzat aquest primer estudi pilot, i en vista dels resultats obtinguts, ens sembla doncs evident que el següent pas de la nostra recerca ha d’anar orientat cap a la formació i regulació professional dels traductors/intèrprets als serveis públics. En concret, en el projecte que sol•licitem ens proposem dissenyar una formació especialitzada per a traductors/intèrprets als serveis públics que compleixi amb els següents tres prerequisits: a) estar oberta a tot tipus de persones, independentment del seu nivell d’estudis; b) oferir un ampli ventall de llengües, principalment les llengües de la immigració a Catalunya (per a una primera selecció d’aquestes llengües, vegeu informe demogràfic de la SIM de l’1 de gener de 2010 i resultats de l’estudi pilot de MIRAS), i c) conduir a una acreditació nacional que reguli l’exercici de la professió de traductor/intèrpret als serveis públics de Catalunya. La implementació d’un sistema d’acreditació, segon objectiu del projecte que presentem, és essencial ja que no només permetrà la regulació d’una professió fins avui poc o mal definida, sinó que també garantirà la qualitat dels serveis oferts per aquests professionals en el futur.

Proactive motivation and engagement in career behaviors: Investigating direct, mediated, and moderated effects

Proactive career behaviors become increasingly important in today's career environment, but little is known about how and when motivational patterns affect individual differences. In a six-month longitudinal study among German university students (Study 1; N = 289) it was demonstrated that motivation in terms of "can do" (self-efficacy and context beliefs), "reason to" (autonomous career goals), and "energized to" (positive affect) significantly predicted career behaviors. Contrary to expectation, negative context beliefs had a positive effect when combined with other motivational states. Study 2 replicated and extended those results by investigating whether "can do" motivation mediates the effect of proactive personality and whether those effects are conditional upon the degree of career choice decidedness. We tested a moderated multiple mediation model with a unique sample of 134 German students, assessed three times, each interval being 6 weeks apart. The results showed that effects of proactivity were partially carried through higher self-efficacy beliefs but not context beliefs. Supporting a moderation model, indirect effects through self-efficacy beliefs were not present for students with very low decidedness.