209 research outputs found

    Characterizing Social Interactions and Grouping Patterns of Sumatran Orangutans (Pongo abelii) in the Gunung Leuser National Park, Sumatra

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    The character of social interactions and grouping patterns of Sumatran orangutans (Pongo abelii) have been studied in Ketambe research station of the Gunung Leuser National Park, Sumatra. A total number of 141 groupings and 47 incidences of interactive behavior were observed during the course of study. The character of groups (feeding group or travel-band) and the type of food trees (fig tree or fruit tree) appear to influence the interactive behavior of individual orangutans. Intolerance behavior has been characterized by feeding group in large fig trees, whereas tolerance and sexual behavior were shown mostly in travel-band

    Emergent Spirograph-like Patterns from Artificial Swarming

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    Computer simulations of a nonlinear planar system of first-order ODEs which we developed from a simple assumption that biological swarming is an outcome of aggregative behavior of the individuals in the swarm showed a surprising and novel outcome; the emergence of uniquely structured patterns that are intriguingly intricate, exquisite, symmetrical and regular. Some patterns look like flowers; others look like Spirograph curves and Guilloché patterns but with more intricate variations. Unlike Spirograph curves though, the swarm-induced patterns cannot be reproduced by any closed-form formula or by another pattern subjected to some resizing, translation, rotation and/or reflection

    A cohesive langrangian swarm and its application to multiple unicycle-like vehicles

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    Swarm principles are increasingly being used to design controllers for the coordination of multi-robot systems or, in general,multi-agent systems. This paper proposes a two-dimensional Lagrangian swarm model that enables the planar agents, modeled as point masses, to swarm whilst effectively avoiding each other and obstacles in the environment. A novel method, based on an extended Lyapunov approach, is used to construct the model. Importantly, the Lyapunov method ensures a form of practical stability that guarantees an emergent behavior, namely, a cohesive and wellspaced swarm with a constant arrangement of individuals about the swarm centroid. Computer simulations illustrate this basic feature of collective behavior. As an application, we show how multiple planar mobile unicycle-like robots swarm to eventually form patterns in which their velocities and orientations stabilize

    Motion Planning and Posture Control of Multiple n-link Doubly Nonholonomic Manipulators

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    The paper considers the problem of motion planning and posture control of multiple n-link doubly nonholonomic mobile manipulators in an obstacle-cluttered and bounded workspace. The workspace is constrained with the existence of an arbitrary number of fixed obstacles (disks, rods and curves), artificial obstacles and moving obstacles. The coordination of multiple n-link doubly nonholonomic mobile manipulators subjected to such constraints becomes therefore a challenging navigational and steering problem that few papers have considered in the past. Our approach to developing the controllers, which are novel decentralized nonlinear acceleration controllers, is based on a Lyapunov control scheme that is not only intuitively understandable but also allows simple but rigorous development of the controllers. Via the scheme, we showed that the avoidance of all types of obstacles was possible, that the manipulators could reach a neighborhood of their goal and that their final orientation approximated the desired orientation. Computer simulations illustrate these results. KEYWORDS: Lyapunov-based control scheme; Doubly nonholonomic manipulators; Ghost parking bays; Minimum distance technique; Stability; Kinodynamic constraints

    Novel Lyapunov - based autonomous controllers for Qquadrotors

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    In this paper, we look into the dynamic motion planning and control of an unmanned aerial vehicle, namely, the quadrotor, governed by its dynamical equations. It is shown for the first time that the Direct or the Second Method of Lyapunov is an effective tool to derive a set of continuous nonlinear control laws that not only provide smooth trajectories from a designated initial position to a designated target, but also continuously minimise the roll and pitch of the quadrotor en route to its targets. The latter successfully addresses the challenging problem of a quadrotor autonomously transporting valuable and fragile payloads safely to the designated target. Computer simulations are used to illustrate the effectiveness of the proposed control laws

    Obstacle and Collision Avoidance Control Laws of a Swarm of Boids

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    This paper proposes a new obstacle and collision avoidance control laws for a three-dimensional swarm of boids. The swarm exhibit collective emergent behaviors whilst avoiding the obstacles in the workspace. While flocking, animals group up in order to do various tasks and even a greater chance of evading predators. A generalized algorithms for attraction to the centroid, inter-individual swarm avoidance and obstacle avoidance is designed in this paper. We present a set of new continuous time-invariant velocity control laws is presented which is formulated via the Lyapunov-based control scheme. The control laws proposed in this paper also ensures practical stability of the system. The effectiveness of the proposed control laws is demonstrated via computer simulations

    Peningkatan motivasi belajar SKI materi Peristiwa Akhir Hayat Rasulullah melalui strategi team quiz pada siswa Kelas V MI Nurul Khoiriyah Glodog Palang Tuban

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    Penelitian ini dilatarbelakangi oleh rendahnya motivasi belajar siswa kelas V dalam mata pelajaran SKI pada materi peristiwa akhir hayat Rasulullah. Hal ini terjadi karena beberapa faktor yaitu, pada awal pembelajaran berlangsung banyak siswa yang belum siap untuk mengikuti kegiatan pembelajaran. Selain itu, guru mata pelajaran SKI kurang menggunakan metode atau strategi pembelajaran yang inovatif dalam menyampaikan materi, sehingga banyak siswa yang merasa bosan, jenuh dan mengantuk saat proses pembelajaran berlangsung. Rumusan masalah dalam penelitian ini adalah: (1) Bagaimana penerapan strategi team quiz dalam meningkatkan motivasi belajar SKI pada materi Peristiwa Akhir Hayat Rasulullah di kelas V MI Nurul Khoiriyah Glodog Palang Tuban? (2) Bagaimana peningkatan motivasi belajar SKI pada materi Peristiwa Akhir Hayat Rasulullah setelah menggunakan strategi team quiz di kelas V MI Nurul Khoiriyah Glodog Palang Tuban? Penelitian ini bertujuan untuk: (1) Mengetahui penerapan strategi team quiz dalam meningkatkan motivasi belajar SKI pada materi Peristiwa Akhir Hayat Rasulullah di kelas V MI Nurul Khoiriyah Glodog Palang Tuban. (2) Mengetahui peningkatan motivasi belajar SKI pada materi Peristiwa Akhir Hayat Rasulullah setelah menggunakan strategi team quiz di kelas V MI Nurul Khoiriyah Glodog Palang Tuban. Jenis penelitian ini adalah penelitian tindakan kelas yang dilaksanakan dalam dua siklus. Penelitian tindakan kelas ini menggunakan model Kurt Lewin, dimana dalam satu siklus terdapat empat langkah pokok, meliputi perencanaan, pelaksanaan, pengamatan atau observasi dan refleksi. Adapun teknik pengumpulan data yang digunakan adalah wawancara, observasi, angket dan dokumentasi. Hasil yang diperoleh dari penelitian ini menunjukkan bahwa motivasi siswa kelas V dalam pembelajaran SKI mengalami peningkatan. Nilai rata-rata motivasi belajar siswa pada pra siklus yaitu 61,86 (kategori rendah) dan kemudian meningkat menjadi 74,34 (kategori cukup) pada siklus I, dan pada siklus II mencapai 84,04 (kategori tinggi). Prosentase ketuntasan motivasi belajar siswa yang berkategori tinggi pada pra siklus yaitu 4,34%, dan kemudian pada siklus I meningkat menjadi 43,47% dan pada siklus II mencapai 82,6%
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