5,057 research outputs found

    RAFCON: a Graphical Tool for Task Programming and Mission Control

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    There are many application fields for robotic systems including service robotics, search and rescue missions, industry and space robotics. As the scenarios in these areas grow more and more complex, there is a high demand for powerful tools to efficiently program heterogeneous robotic systems. Therefore, we created RAFCON, a graphical tool to develop robotic tasks and to be used for mission control by remotely monitoring the execution of the tasks. To define the tasks, we use state machines which support hierarchies and concurrency. Together with a library concept, even complex scenarios can be handled gracefully. RAFCON supports sophisticated debugging functionality and tightly integrates error handling and recovery mechanisms. A GUI with a powerful state machine editor makes intuitive, visual programming and fast prototyping possible. We demonstrated the capabilities of our tool in the SpaceBotCamp national robotic competition, in which our mobile robot solved all exploration and assembly challenges fully autonomously. It is therefore also a promising tool for various RoboCup leagues.Comment: 8 pages, 5 figure

    Feasibility study for a numerical aerodynamic simulation facility. Volume 2: Hardware specifications/descriptions

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    An FMP (Flow Model Processor) was designed for use in the Numerical Aerodynamic Simulation Facility (NASF). The NASF was developed to simulate fluid flow over three-dimensional bodies in wind tunnel environments and in free space. The facility is applicable to studying aerodynamic and aircraft body designs. The following general topics are discussed in this volume: (1) FMP functional computer specifications; (2) FMP instruction specification; (3) standard product system components; (4) loosely coupled network (LCN) specifications/description; and (5) three appendices: performance of trunk allocation contention elimination (trace) method, LCN channel protocol and proposed LCN unified second level protocol

    Open Piping: Towards an Open Visual Workflow Environment

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    The most popular visual programming tools focus on procedural, object-oriented and event-based programming. This paper describes a boxes-and-wires functional programming tool, aimed to be accessible to novice programmers, while also supporting open access to the specified processes, executable programs and results for study and deployment

    Posttraumatic pseudolipoma: MRI appearances

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    The goal of this study was to describe the MRI characteristics of posttraumatic pseudolipomas. Ten patients with previous history of blunt trauma or local surgery were investigated with MRI at the level of their deformity. The etiology was blunt trauma in eight patients and postoperative trauma in two. For all patients medical documentation, in the form of clinical history and physical examination, confirmed that a visible hematoma was present acutely at the same location following the injury and that the contour deformity subsequently appeared. All patients underwent liposuction. Preoperative bilateral MRI examinations were performed on all patients. The mean clinical follow-up was 17.8 months. MRI examinations were interpreted in consensus by two experienced musculoskeletal radiologists with attention to fatty extension (subcutaneous fatty thickness and anatomical extension), asymmetry compared with the asymptomatic side, the presence or absence of fibrous septae or nonfatty components, and patterns of contrast enhancement. Ten posttraumatic pseudolipomas were identified. Clinically, they showed as subcutaneous masses with the consistency of normal adipose tissue. Their locations were the abdomen (n=1), hip (n=1), the upper thigh (n=6), the knee (n=1), and the ankle (n=1). On MRI examinations, using the contralateral side as a control, pseudolipomas appeared as focal fatty masses without a capsule or contrast enhancement. Posttraumatic pseudolipomas may develop at a site of blunt trauma or surgical procedures often antedated by a soft tissue hematoma. Characteristic MRI findings are unencapsulated subcutaneous fatty masses without contrast enhancemen

    About Gravitomagnetism

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    The gravitomagnetic field is the force exerted by a moving body on the basis of the intriguing interplay between geometry and dynamics which is the analog to the magnetic field of a moving charged body in electromagnetism. The existence of such a field has been demonstrated based on special relativity approach and also by special relativity plus the gravitational time dilation for two different cases, a moving infinite line and a uniformly moving point mass, respectively. We treat these two approaches when the applied cases are switched while appropriate key points are employed. Thus, we demonstrate that the strength of the resulted gravitomagnetic field in the latter approach is twice the former. Then, we also discuss the full linearized general relativity and show that it should give the same strength for gravitomagnetic field as the latter approach. Hence, through an exact analogy with the electrodynamic equations, we present an argument in order to indicate the best definition amongst those considered in this issue in the literature. Finally, we investigate the gravitomagnetic effects and consequences of different definitions on the geodesic equation including the second order approximation terms.Comment: 16 pages, a few amendments have been performed and a new section has been adde

    Global well-posedness for a slightly supercritical surface quasi-geostrophic equation

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    We use a nonlocal maximum principle to prove the global existence of smooth solutions for a slightly supercritical surface quasi-geostrophic equation. By this we mean that the velocity field uu is obtained from the active scalar θ\theta by a Fourier multiplier with symbol ikk1m(k)i k^\perp |k|^{-1} m(k|), where mm is a smooth increasing function that grows slower than loglogk\log \log |k| as k|k|\rightarrow \infty.Comment: 11 pages, second version with slightly stronger resul

    Method for fabricating a low stress x-ray mask using annealable amorphous refractory compounds

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    X‐ray masks have been fabricated by depositing a compressively stressed refractory material on a wafer, annealing to a zero stress state, and then forming the membrane. Amorphous TaSiN and TaSi alloys deposited with a magnetron sputter tool have been extensively characterized in terms of resistivity, composition, defectivity, surface roughness, and crystalline state. Optimization in terms of these parameters has resulted in base line selection of absorber films of the following compositions: Ta_(61)Si_(17)N_(21) and Ta_(75)Si_(23). The process is shown to be extendable to an entire class of amorphous annealable refractory materials. Careful studies of deposition and annealing conditions have resulted in a 4× reduction of image placement to the 30 nm maximum vector level. Finally, the importance of stress gradients is experimentally verified

    Reconstruction and architecture of medullosan pteridosperms (Pennsylvanian)

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    A new reconstruction of the architecture of medullosan pteridosperms is proposed on the basis of three stems preserved as compression-impression fossils: one from the Southern Anthracite Coal Field of Pennsylvania (lower part of Llewellyn Formation, Pennsylvania, Westphalian D) probably belonging to Alethopteris foliage; a second stem from the roof shale of the Eagle coal bed (Kanawha Formation, Middle Pennsylvanian, Westphalian B) of West Virginia, associated with Neuropteris foliage; and a third reported from the Stephanian of Commentry, France, in connection with Odontopteris foliage. The diameters of the Llewellyn, Eagle, and Commentry stems are 17 cm, 13 cm, and 6.5 cm, respectively. All three stems bear remnants of petioles up to several centimeters in length. The petolar remnants indicate that the living leaves grew upward at an angle of 30 - 60 degrees from the vertical, a growth habit that is common in present day tropical plants with similar overall architecture. Leaves drooped only when they were dying. After decay they broke off and left short petiolar remnants bent downward. The Llewellyn and Eagle stems represent plants with thick, straight stems, whereas the Commentry specimen shows a thin and slightly curved stem
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