Information driven self-organization of complex robotic behaviors

Information theory is a powerful tool to express principles to drive autonomous systems because it is domain invariant and allows for an intuitive interpretation. This paper studies the use of the predictive information (PI), also called excess entropy or effective measure complexity, of the sensorimotor process as a driving force to generate behavior. We study nonlinear and nonstationary systems and introduce the time-local predicting information (TiPI) which allows us to derive exact results together with explicit update rules for the parameters of the controller in the dynamical systems framework. In this way the information principle, formulated at the level of behavior, is translated to the dynamics of the synapses. We underpin our results with a number of case studies with high-dimensional robotic systems. We show the spontaneous cooperativity in a complex physical system with decentralized control. Moreover, a jointly controlled humanoid robot develops a high behavioral variety depending on its physics and the environment it is dynamically embedded into. The behavior can be decomposed into a succession of low-dimensional modes that increasingly explore the behavior space. This is a promising way to avoid the curse of dimensionality which hinders learning systems to scale well.Comment: 29 pages, 12 figure

Central bank´s value at risk and financial crises: An application to the 2001 Argentine crisis

Blejer and Schumacher (1999) were the first to suggest that Central Bank’s Value at Risk (VaR), a widely used composite measure of potential portfolio losses in the corporate sector, could be used as an early warning indicator of financial crises. We extend their research in two aspects. First, we develop an operational model to calculate Central Bank’s VaR and illustrate the methodology using data from the recent financial crisis in Argentina. Second, we compare the predictive performance of diverse measures based on the VaR approach to that of another well known early warning system, the signals approach, and several univariate leading indicators. The results reveal a strong relationship between the measures proposed and the crisis. Furthermore, one of the measures provides higher accuracy and announces the probability of a crisis sooner than the competing indicators.currency crises, Argentina, value at risk

IPOs and the Slow Death of Section 5

Since its enactment, Section 5 of the Securities Act of 1933 has restricted sales-based communications with investors, but that effort is nearly dead even with respect to the most sensitive of offerings, the IPO. Our paper traces that devolution, which began almost as soon as the ’33 Act came into existence, though the SEC’s 2005 deregulatory reforms and Congress’ intervention in the JOBS Act of 2012. We show how much of this related to an embrace of “book-building” as the industry’s preferred method of price discovery, which requires private two-way communications between underwriters and potential sophisticated investors. But book-building (and the predictable IPO underpricing that results) has a retail dimension as well, and we point to ways in which the otherwise sensible deregulation may enable an over-stimulation of retail investor demand. We then explore two main justifications that have been given for the aggressive deregulation. The first is that any loss in prophylactic protection can be made up for by the threat of liability, particularly with an enhanced Section 12(a)(2). We find this unpersuasive for a variety of reasons. The other—amply visible in the long history of Section 5—is a faith in the “filtration” process, that retail investors gain protection because of the availability of the preliminary prospectus during the waiting period, to those involved in the selling process if not the investors themselves. Putting aside the biased incentives that affect filtration, much of what is most important—and conveyed privately to the institutions in the course of book-building—is forward-looking information that probably need not appear in the formal disclosure, whether preliminary or final. None of this is an argument for returning to the old prophylactics of Section 5. But it is cause for the SEC and FINRA to pay close attention to the retail investor effects of the IPO selling practices, especially in the post-JOBS Act era

Spectators’ aesthetic experiences of sound and movement in dance performance

In this paper we present a study of spectators’ aesthetic experiences of sound and movement in live dance performance. A multidisciplinary team comprising a choreographer, neuroscientists and qualitative researchers investigated the effects of different sound scores on dance spectators. What would be the impact of auditory stimulation on kinesthetic experience and/or aesthetic appreciation of the dance? What would be the effect of removing music altogether, so that spectators watched dance while hearing only the performers’ breathing and footfalls? We investigated audience experience through qualitative research, using post-performance focus groups, while a separately conducted functional brain imaging (fMRI) study measured the synchrony in brain activity across spectators when they watched dance with sound or breathing only. When audiences watched dance accompanied by music the fMRI data revealed evidence of greater intersubject synchronisation in a brain region consistent with complex auditory processing. The audience research found that some spectators derived pleasure from finding convergences between two complex stimuli (dance and music). The removal of music and the resulting audibility of the performers’ breathing had a significant impact on spectators’ aesthetic experience. The fMRI analysis showed increased synchronisation among observers, suggesting greater influence of the body when interpreting the dance stimuli. The audience research found evidence of similar corporeally focused experience. The paper discusses possible connections between the findings of our different approaches, and considers the implications of this study for interdisciplinary research collaborations between arts and sciences

Europeanisation Strategy of Chinese Companies: Its Perils and Promises

The magnitude of outward FDI from China over the recent years has been impressive. It is widely acknowledged that China's government plays an active role in encouraging its companies to go global and become multinational as they realise the value of outward FDI. The paper traces the development of China's outward direct investment policies and discusses the various motives of Chinese companies' internationalisation. More specifically, in this paper we look at the European continent as the emerging destination for Chinese outward direct investment and analyse the implication this trend has for European companies and governments.China, multinational companies, emerging economies, outward investment, public policy

Patterns and Collective Behavior in Granular Media: Theoretical Concepts

Granular materials are ubiquitous in our daily lives. While they have been a subject of intensive engineering research for centuries, in the last decade granular matter attracted significant attention of physicists. Yet despite a major efforts by many groups, the theoretical description of granular systems remains largely a plethora of different, often contradicting concepts and approaches. Authors give an overview of various theoretical models emerged in the physics of granular matter, with the focus on the onset of collective behavior and pattern formation. Their aim is two-fold: to identify general principles common for granular systems and other complex non-equilibrium systems, and to elucidate important distinctions between collective behavior in granular and continuum pattern-forming systems.Comment: Submitted to Reviews of Modern Physics. Full text with figures (2Mb pdf) avaliable at http://mti.msd.anl.gov/AransonTsimringReview/aranson_tsimring.pdf Community responce is appreciated. Comments/suggestions send to [email protected]

Children’s Risky Play from an Evolutionary Perspective: The Anti-Phobic Effects of Thrilling Experiences

This theoretical article views children’s risky play from an evolutionary perspective, addressing specific evolutionary functions and especially the anti-phobic effects of risky play. According to the non-associative theory, a contemporary approach to the etiology of anxiety, children develop fears of certain stimuli (e.g., heights and strangers) that protect them from situations they are not mature enough to cope with, naturally through infancy. Risky play is a set of motivated behaviors that both provide the child with an exhilarating positive emotion and expose the child to the stimuli they previously have feared. As the child’s coping skills improve, these situations and stimuli may be mastered and no longer be feared. Thus fear caused by maturational and age relevant natural inhibition is reduced as the child experiences a motivating thrilling activation, while learning to master age adequate challenges. It is concluded that risky play may have evolved due to this anti-phobic effect in normal child development, and it is suggested that we may observe an increased neuroticism or psychopathology in society if children are hindered from partaking in age adequate risky play.Children’s Risky Play from an Evolutionary Perspective: The Anti-Phobic Effects of Thrilling ExperiencespublishedVersio

POLYMERIC IMPULSIVE ACTUATION MECHANISMS: DEVELOPMENT, CHARACTERIZATION, AND MODELING

Recent advances in the field of biomedical and life-sciences are increasingly demanding more life-like actuation with higher degrees of freedom in motion at small scales. Many researchers have developed various solutions to satisfy these emerging requirements. In many cases, new solutions are made possible with the development of novel polymeric actuators. Advances in polymeric actuation not only addressed problems concerning low degree of freedom in motion, large system size, and bio-incompatibility associated with conventional actuators, but also led to the discovery of novel applications, which were previously unattainable with conventional engineered systems. This dissertation focuses on developing novel actuation mechanisms for soft polymeric gel systems with easily adjustable mechanochemical properties and applicability to various environmental conditions. Inspired by stunning examples in nature which exhibit extremely fast motion in a repeatable manner, termed impulsive motion, we have developed polymeric gel actuators applicable for small-scale, self-contained impulsive systems. In particular, we focused on the effect of geometry and the mechanics of surface-mediated stresses on the dynamic shape-change of polymer gel actuators. We found new opportunities from observation of transient deformations which occur during swelling, or deswelling, of asymmetric gels. We described the development of time-dependent three-dimensional deformation mechanism (4D fabrication) by the utilization of transient inhomogeneous swelling state of the asymmetric polymer gel. We discussed the mechanism and the application of the new deformations mechanism for the development of a novel functionality: chemical gradient sensor. In addition, we developed a high-rate and large-strain reversible actuation mechanism for sub-micrometer scale polymeric gel actuators by utilizing balanced effects of two surface-mediated phenomena, surface diffusion and interfacial-tension, and elasticity of soft and small-scale hydrogels. These new findings were harnessed for developing autonomously controlled power amplified polymeric gel devices. Utilizing deswelling induced transient deformation of gel, we developed design principles for generating meta-stable structures and inducing self-regulating transition forces for repeated snap-through buckling transition of polymeric gel devices. In parallel, we deconvoluted the effect of material properties and geometry on dynamic deformations by establishing simulation models and conducting analyses on the performances of actual synthetic systems. The systematic approach will serve to broaden the application spectrum and manufacturing possibilities of polymeric actuator systems

Investigation of Water Droplet Dynamics in PEM Cell Gas Channels

Water management in Proton Exchange Membrane Fuel Cell (PEMFC) has remained one of the most important issues that need to be addressed before its commercialization in automotive applications. Accumulation of water on the gas diffusion layer (GDL) surface in a PEMFC introduces a barrier for transport of reactant gases through the GDL to the catalyst layer. Despite the fact that the channel geometry is one of the key design parameters of a fluidic system, very limited research is available to study the effect of microchannel geometry on the two-phase flow structure. In this study, the droplet-wall dynamics and two-phase pressure drop across the water droplet present in a typical PEMFC channel, were examined in auto-competitive gas channel designs (0.4 x 0.7 mm channel cross section). The liquid water flow pattern inside the gas channel was analyzed for different air velocities. Experimental data was analyzed using the Concus-Finn condition to determine the wettability characteristics in the corner region. It was confirmed that the channel angle along with the air velocity and the channel material influences the water distribution and holdup within the channel. Dynamic contact angle emerged as an important parameter in controlling the droplet-wall interaction. Experiments were also performed to understand how the inlet location of the liquid droplet on the GDL surface affects the droplet dynamic behavior in the system. It was found that droplets emerging near the channel wall or under the land lead to corner filling of the channel. Improvements in the channel design has been proposed based on the artificial channel roughness created to act as capillary grooves to transport the liquid water away from the land area. For droplets emerging near the center of the channel, beside the filling and no-filling behavior reported in the literature, a new droplet jumping behavior was observed. As droplets grew and touched the sidewalls, they jumped off to the sidewall leaving the whole GDL exposed for gases to diffuse to the catalyst layer. A theoretical model was developed and a criterion was proposed to predict the droplet jumping behavior in the gas channel. A theoretical force balance model was proposed to predict the pressure force and air velocity required to remove the droplet from the channel to avoid complete channel blockage. The overall goal of this work was to identify the gas channel configuration that provides efficient water removal with a lower pressure drop in the system efficiency while meeting the US Department of Energy\u27s specifications for a PEMFC for automotive application

Evolution of trade patterns in the new EU member states

The paper analyses the most recent evolution of the trade specialisation pattern in the 10 new EU Member States. Relying on the empirical approach of the Markov transition matrices it analyses both the changes in the external shape of the distribution of comparative advantages and the intra-distribution dynamics. The new Members show an indeed dynamic trade pattern; they were able to gain comparative advantages relatively fast in sectors in which they were lagging behind at the beginning of the transition process, notably in some “high tech” products. In addition, many specialisation improvements occurred in those items for which the world demand expands at the fastest rate, hinting to the possibility of an increase in their trade shares on world markets. Both findings can be explained by the initial need to rebuild and modernise the entire capital stock, the significant skilled-labour force endowment, and the large FDI inflows that allowed them to skip intermediate states of technological development.Revealed comparative advantages, international specialization model, distribution dynamics