638 research outputs found

    Adaptive Robotic Control Driven by a Versatile Spiking Cerebellar Network

    Get PDF
    The cerebellum is involved in a large number of different neural processes, especially in associative learning and in fine motor control. To develop a comprehensive theory of sensorimotor learning and control, it is crucial to determine the neural basis of coding and plasticity embedded into the cerebellar neural circuit and how they are translated into behavioral outcomes in learning paradigms. Learning has to be inferred from the interaction of an embodied system with its real environment, and the same cerebellar principles derived from cell physiology have to be able to drive a variety of tasks of different nature, calling for complex timing and movement patterns. We have coupled a realistic cerebellar spiking neural network (SNN) with a real robot and challenged it in multiple diverse sensorimotor tasks. Encoding and decoding strategies based on neuronal firing rates were applied. Adaptive motor control protocols with acquisition and extinction phases have been designed and tested, including an associative Pavlovian task (Eye blinking classical conditioning), a vestibulo-ocular task and a perturbed arm reaching task operating in closed-loop. The SNN processed in real-time mossy fiber inputs as arbitrary contextual signals, irrespective of whether they conveyed a tone, a vestibular stimulus or the position of a limb. A bidirectional long-term plasticity rule implemented at parallel fibers-Purkinje cell synapses modulated the output activity in the deep cerebellar nuclei. In all tasks, the neurorobot learned to adjust timing and gain of the motor responses by tuning its output discharge. It succeeded in reproducing how human biological systems acquire, extinguish and express knowledge of a noisy and changing world. By varying stimuli and perturbations patterns, real-time control robustness and generalizability were validated. The implicit spiking dynamics of the cerebellar model fulfill timing, prediction and learning functions.European Union (Human Brain Project) REALNET FP7-ICT270434 CEREBNET FP7-ITN238686 HBP-60410

    Pacific Symposium on Biocomputing 2023

    Get PDF
    The Pacific Symposium on Biocomputing (PSB) 2023 is an international, multidisciplinary conference for the presentation and discussion of current research in the theory and application of computational methods in problems of biological significance. Presentations are rigorously peer reviewed and are published in an archival proceedings volume. PSB 2023 will be held on January 3-7, 2023 in Kohala Coast, Hawaii. Tutorials and workshops will be offered prior to the start of the conference.PSB 2023 will bring together top researchers from the US, the Asian Pacific nations, and around the world to exchange research results and address open issues in all aspects of computational biology. It is a forum for the presentation of work in databases, algorithms, interfaces, visualization, modeling, and other computational methods, as applied to biological problems, with emphasis on applications in data-rich areas of molecular biology.The PSB has been designed to be responsive to the need for critical mass in sub-disciplines within biocomputing. For that reason, it is the only meeting whose sessions are defined dynamically each year in response to specific proposals. PSB sessions are organized by leaders of research in biocomputing's 'hot topics.' In this way, the meeting provides an early forum for serious examination of emerging methods and approaches in this rapidly changing field

    Model-driven analysis of eyeblink classical conditioning reveals the underlying structure of cerebellar plasticity and neuronal activity

    Get PDF
    The cerebellum plays a critical role in sensorimotor control. However, how the specific circuits and plastic mechanisms of the cerebellum are engaged in closed-loop processing is still unclear. We developed an artificial sensorimotor control system embedding a detailed spiking cerebellar microcircuit with three bidirectional plasticity sites. This proved able to reproduce a cerebellar-driven associative paradigm, the eyeblink classical conditioning (EBCC), in which a precise time relationship between an unconditioned stimulus (US) and a conditioned stimulus (CS) is established. We challenged the spiking model to fit an experimental data set from human subjects. Two subsequent sessions of EBCC acquisition and extinction were recorded and transcranial magnetic stimulation (TMS) was applied on the cerebellum to alter circuit function and plasticity. Evolutionary algorithms were used to find the near-optimal model parameters to reproduce the behaviors of subjects in the different sessions of the protocol. The main finding is that the optimized cerebellar model was able to learn to anticipate (predict) conditioned responses with accurate timing and success rate, demonstrating fast acquisition, memory stabilization, rapid extinction, and faster reacquisition as in EBCC in humans. The firing of Purkinje cells (PCs) and deep cerebellar nuclei (DCN) changed during learning under the control of synaptic plasticity, which evolved at different rates, with a faster acquisition in the cerebellar cortex than in DCN synapses. Eventually, a reduced PC activity released DCN discharge just after the CS, precisely anticipating the US and causing the eyeblink. Moreover, a specific alteration in cortical plasticity explained the EBCC changes induced by cerebellar TMS in humans. In this paper, for the first time, it is shown how closed-loop simulations, using detailed cerebellar microcircuit models, can be successfully used to fit real experimental data sets. Thus, the changes of the model parameters in the different sessions of the protocol unveil how implicit microcircuit mechanisms can generate normal and altered associative behaviors

    Sensors Fault Diagnosis Trends and Applications

    Get PDF
    Fault diagnosis has always been a concern for industry. In general, diagnosis in complex systems requires the acquisition of information from sensors and the processing and extracting of required features for the classification or identification of faults. Therefore, fault diagnosis of sensors is clearly important as faulty information from a sensor may lead to misleading conclusions about the whole system. As engineering systems grow in size and complexity, it becomes more and more important to diagnose faulty behavior before it can lead to total failure. In the light of above issues, this book is dedicated to trends and applications in modern-sensor fault diagnosis

    The Optimal Employment of Supply Chain management Decision Support Agents: an Exploratory Study

    Get PDF
    The issue of interest here is the employment of decision support agents in supply chain management. The study discusses the sorts of supply-related managerial tasks that decision support agents have been assigned, and how well or poorly they have performed these tasks. This research suggests the reasons why organizations might elect to invest supply chain management responsibilities in decision support agents rather than human functionaries. Finally, this research concludes by presenting a best fit construct for optimal decision making opportunities

    The Boston University Photonics Center annual report 2009-2010

    Full text link
    This repository item contains an annual report that summarizes activities of the Boston University Photonics Center for the period from July 2009 through June 2010. The report provides quantitative and descriptive information regarding photonics programs in education, interdisciplinary research, business innovation, and technology development. The Boston University Photonics Center (BUPC) is an interdisciplinary hub for education, research, scholarship, innovation, and technology development associated with practical uses of light.This report summarizes activities of the Boston University Photonics Center (BUPC) during the period July 2009 through June 2010. These activities span the Center’s complementary missions in education, research, technology development, and commercialization. In education, twenty-three BUPC graduate students received Ph.D. diplomas. BUPC faculty taught thirty-one photonics courses. Five graduate students were funded through the Photonics Fellowship Program. BUPC supported a Research Experiences for Undergraduates (REU) site in Photonics, which hosted summer interns in a ten-week program. Each REU student presented their research results to a panel of faculty and graduate students. Professors Goldberg and Swan continued their work with K-12 student outreach programs. Professor Goldberg’s Boston Urban Fellows Project started its sixth year. Professor Swan’s collaborative Four Schools for Women in Engineering program entered its third year. For more on our education programs, turn to the Education section on page 67. In research, BUPC faculty published journal papers spanning the field of photonics. Twelve patents were awarded to faculty this year for new innovations in the field. A number of awards for outstanding achievement in education and research were presented to BUPC faculty members. These honors include NSF CAREER Awards for Professors Altug, Dal Negro and Reinhard. New external grant funding for the 2009-2010 fiscal year totaled 21.1M,including21.1M, including 4.0M through a Cooperative Agreement with the U.S. Army Research Laboratory (ARL). For more information on our research activities, turn to the Research section on page 24. In technology development, the Department of Defense (DoD) continued to support the COBRA prototype systems. These photonics-technologies were pioneered by BUPC faculty and staff and have been deployed for field test and use at the United States Army Medical Research Institute for Infectious Diseases. New technology development projects for nuclear weapon detection, biodosimetry and terahertz imaging were launched and previously developed technologies for bacterial and viral sensing advanced toward commercial transition. For more information on our technology development pipeline and projects, turn to the Technology Development section on page 54. In commercialization, the business incubator continues to operate at capacity. Its tenants include more than a dozen technology companies with core business interests primarily in photonics and life sciences. It houses several companies founded by current and former BU faculty and students and provides students with an opportunity to assist, observe, and learn from start-up companies. For more information about business incubator activities, turn to the Business Incubation chapter in the Facilities and Equipment section on page 84. In early 2010, the BUPC unveiled a five-year strategic plan as part of the University’s comprehensive review of centers and institutes. The BUPC strategic plan will enhance the Center’s position as an international leader in photonics research. For more information about the strategic plan, turn to the BUPC Strategic Plan section on page 8

    Institute of Safety Research; Annual Report 1993

    Get PDF
    The report gives an overview on the scientific work of the Institute of Safety Research in 1993
    • …
    corecore