1,493 research outputs found

    Adaptive tracking control of nonholonomic systems: an example

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    We study an example of an adaptive (state) tracking control problem for a four-wheel mobile robot, as it is an illustrative example of the general adaptive state-feedback tracking control problem. It turns out that formulating the adaptive state-feedback tracking control problem is not straightforward, since specifying the reference state-trajectory can be in conflict with not knowing certain parameters. Our example illustrates this difficulty and we propose a problem formulation for the adaptive state-feedback tracking problem that meets the natural prerequisite that it reduces to the state-feedback tracking problem if the parameters are known. A general methodology for solving the problem is derive

    On the possible divergence of the projection algorithm

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    By means of an example, the authors show that the sequence of estimates generated by the projection algorithm does not always converge. The authors' construction shows that convergence is not automatically among the properties that can be derived without additional assumptions on the input sequenc

    Bounded tracking controllers for the chaotic (forced) Duffing equation

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    This paper deals with the design of feedback controllers for a chaotic dynamical system like the Duffing equation. Lyapunov theory is used to show that the proposed bounded controllers achieve global convergence for any desired trajectory. Some simulation examples illustrate the presented idea

    Nothing Comes to Her Who Sits and Waits: The League of Women Voters and Citizenship After Woman Suffrage, 1920-1940

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    Rather than viewing the Nineteenth Amendment as an endpoint of the woman suffrage movement, this amendment should instead be viewed as a stop along the way. No one piece of legislation guaranteed all women the right to vote, nor did the Nineteenth Amendment grant women equal citizenship status with men. Founded in 1919, the League of Women Voters of Iowa became the successor of the Iowa Equal Suffrage Association, carrying on a legacy of activism and resistance to gender-based discrimination. While the right to vote made up a large part of what most suffragists thought of as citizenship, many women quickly realized there were other legal and social discriminations against women that limited women’s autonomy. The League of Women Voters of Iowa (LWV of Iowa) continued to fight for gender equality, capitalizing on the existing organizational structures left behind by the Iowa Equal Suffrage Association. Moving into the 1920s and 1930\u27s, the League of Women Voters of Iowa participated in the enduring women\u27s movement, focusing primarily on women-specific legislation and reform, as well as voter education and educated suffrage. This paper utilizes primary archival sources to argue that the LWV of Iowa’s activity between 1920 and 1940 demonstrates the continuation of the women\u27s movement post-Nineteenth Amendment during a period many scholars view as a silent period for women’s activism. In cooperation with the National League of Women Voters, the LWV of Iowa worked to define and redefine citizenship throughout the 1920s and 1940s at both the state and national levels

    Isolation, Identification, Modification, and Biological Analysis of extracts of A. Mexicana

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    Argemone mexicana is a member of the Papaveraceae family of plants that has been used for centuries in traditional medicine by indigenous communities in Mexico and the United States. Through a collaborative project, we have explored separation of key components of the seeds and leaves of this plant to isolate the source of their biological activity. We have already identified two key molecules which give this plant anti-microbial properties against the gram-positive bacteria. Furthermore, we have chemically modified one of these molecules to observe variations on activity. We hope this leads to the discovery of new antibiotic drugs

    Working With Children Using Dance/Movement Therapy

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    Movement is a language. We all learned to relate on a nonverbal level before starting to communicate verbally. Thus, this nonverbal language of the body is especially powerful for children, who communicate, navigate relationships, and interact with their environment through movement. An early, healthy connection with their bodies enables children to develop a strong sense of self and dynamic sense of both their body image and physical boundaries. For all of these reasons, dance/ movement therapy is a highly effective modality for working with children. This chapter introduces the field of dance/movement therapy, specifically as it relates to working with children. An overview of the field is covered, as well as general goals for working with children and case studies that exemplify these goals. Children are a unique population for the work of a dance/movement therapist, because the limited verbal abilities of children may make it more difficult for them to reach out and express themselves. When words fail, dance/movement therapy fosters children’s ability to relate, communicate, and connect on a nonverbal level. Dance/movement therapy utilizes body movement as both a method for assessment and a treatment modalit

    A motion system for social and animated robots

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    This paper presents an innovative motion system that is used to control the motions and animations of a social robot. The social robot Probo is used to study Human-Robot Interactions (HRI), with a special focus on Robot Assisted Therapy (RAT). When used for therapy it is important that a social robot is able to create an "illusion of life" so as to become a believable character that can communicate with humans. The design of the motion system in this paper is based on insights from the animation industry. It combines operator-controlled animations with low-level autonomous reactions such as attention and emotional state. The motion system has a Combination Engine, which combines motion commands that are triggered by a human operator with motions that originate from different units of the cognitive control architecture of the robot. This results in an interactive robot that seems alive and has a certain degree of "likeability". The Godspeed Questionnaire Series is used to evaluate the animacy and likeability of the robot in China, Romania and Belgium

    The Movement’s Message: Dance/Movement Therapy & Children with Autism

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    Movement is a language. For children affected by autism, movement may be the only language they can rely on. Children with autism often have limited verbal abilities, making it extremely difficult for them to reach out (Hartshorn et al., 2001). When words fail, dance/movement therapy fosters a child’s ability to relate, communicate, and connect on a nonverbal level. This chapter will outline the use of dance/movement therapy with children on the autism spectrum. Specifically, it will introduce concepts of movement analysis and examine the potential in using movement-based assessments to create therapy goals and movement interventions for practical application. This chapter includes case studies of two females (ages 3 and 11). These individuals receive services for autism-related diagnoses at a treatment center for children on the spectrum. The case studies will focus on the movement qualities and challenges unique to children with autism. Laban Movement Analysis, a complex system used to observe, describe, notate, and understand movement patterns (Hackney, 2002), will be introduced and used to decipher the movement profiles of the case study females. Dance/movement therapists are trained to observe and assess movement using this system and then make therapeutic interventions using their move-ment analyses. The other half of their clinical training is psychotherapeutic in nature. In a related but divergent vein from dance/movement therapy training programs, certified movement analysts complete comprehensive movement analysis programs where the observation and assessment of movement is at the core of their studies. For the purpose of the case studies described here, a Certified Laban Movement Analyst (CLMA) provided analyses, in addition to my own, in order to both enhance and provide reliability for the work. Portions of these analyses will be examined to discuss the use of formal movement analysis as an instrument for creating treatment goals
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