9,183 research outputs found

    A high speed Tri-Vision system for automotive applications

    Get PDF
    Purpose: Cameras are excellent ways of non-invasively monitoring the interior and exterior of vehicles. In particular, high speed stereovision and multivision systems are important for transport applications such as driver eye tracking or collision avoidance. This paper addresses the synchronisation problem which arises when multivision camera systems are used to capture the high speed motion common in such applications. Methods: An experimental, high-speed tri-vision camera system intended for real-time driver eye-blink and saccade measurement was designed, developed, implemented and tested using prototype, ultra-high dynamic range, automotive-grade image sensors specifically developed by E2V (formerly Atmel) Grenoble SA as part of the European FP6 project – sensation (advanced sensor development for attention stress, vigilance and sleep/wakefulness monitoring). Results : The developed system can sustain frame rates of 59.8 Hz at the full stereovision resolution of 1280 × 480 but this can reach 750 Hz when a 10 k pixel Region of Interest (ROI) is used, with a maximum global shutter speed of 1/48000 s and a shutter efficiency of 99.7%. The data can be reliably transmitted uncompressed over standard copper Camera-Link® cables over 5 metres. The synchronisation error between the left and right stereo images is less than 100 ps and this has been verified both electrically and optically. Synchronisation is automatically established at boot-up and maintained during resolution changes. A third camera in the set can be configured independently. The dynamic range of the 10bit sensors exceeds 123 dB with a spectral sensitivity extending well into the infra-red range. Conclusion: The system was subjected to a comprehensive testing protocol, which confirms that the salient requirements for the driver monitoring application are adequately met and in some respects, exceeded. The synchronisation technique presented may also benefit several other automotive stereovision applications including near and far-field obstacle detection and collision avoidance, road condition monitoring and others.Partially funded by the EU FP6 through the IST-507231 SENSATION project.peer-reviewe

    Recent Sikorsky R and D progress

    Get PDF
    The recent activities and progress in four specific areas of Sikorsky's research and development program are summarized. Since the beginning of the S-76 design in 1974, Sikorsky has been aggressively developing the technology for using composite materials in helicopter design. Four specific topics are covered: advanced cockpit/controller efforts, fly-by-wire controls on RSRA/X-Wing, vibration control via higher harmonic control, and main rotor aerodynamic improvements

    The Development of Unique Focal Planes for High-Resolution Suborbital and Ground-Based Exploration

    Get PDF
    abstract: The development of new Ultra-Violet/Visible/IR range (UV/Vis/IR) astronomical instrumentation that use novel approaches for imaging and increase the accessibility of observing time for more research groups is essential for rapid innovation within the community. Unique focal planes that are rapid-prototyped, low cost, and provide high resolution are key. In this dissertation the emergent designs of three unique focal planes are discussed. These focal planes were each designed for a different astronomical platform: suborbital balloon, suborbital rocket, and ground-based observatory. The balloon-based payload is a hexapod-actuated focal plane that uses tip-tilt motion to increase angular resolution through the removal of jitter – known as the HExapod Resolution-Enhancement SYstem (HERESY), the suborbital rocket imaging payload is a Jet Propulsion Laboratory (JPL) delta-doped charge-coupled device (CCD) packaged to survive the rigors of launch and image far-ultra-violet (FUV) spectra, and the ground-based observatory payload is a star centroid tracking modification to the balloon version of HERESY for the tip-tilt correction of atmospheric turbulence. The design, construction, verification, and validation of each focal plane payload is discussed in detail. For HERESY’s balloon implementation, pointing error data from the Stratospheric Terahertz Observatory (STO) Antarctic balloon mission was used to form an experimental lab test setup to demonstrate the hexapod can eliminate jitter in flight-like conditions. For the suborbital rocket focal plane, a harsh set of unit-level tests to ensure the payload could survive launch and space conditions, as well as the characterization and optimization of the JPL detector, are detailed. Finally, a modification of co-mounting a fast-read detector to the HERESY focal plane, for use on ground-based observatories, intended to reduce atmospherically induced tip-tilt error through the centroid tracking of bright natural guidestars, is described.Dissertation/ThesisDoctoral Dissertation Exploration Systems Design 201

    Methodological Approach for the Development of a Simplified Residential Building Energy Estimation in Temperate Climate

    Get PDF
    Energy ratings and minimum requirements for thermal envelopes and heating and air conditioning systems emerged as tools to minimize energy consumption and greenhouse gas emissions, improve energy e ciency and promote greater transparency with regard to energy use in buildings. In Latin America, not all countries have building energy e ciency regulations, many of them are voluntary and more than 80% of the existing initiatives are simplified methods and are centered in energy demand analysis and the compliance of admissible values for di erent indicators. However, the application of these tools, even when simplified, is reduced. The main objective is the development of a simplified calculation method for the estimation of the energy consumption of multifamily housing buildings. To do this, an energy model was created based on the real use and occupation of a reference building, its thermal envelope and its thermal system’s performance. This model was simulated for 42 locations, characterized by their climatic conditions, whilst also considering the thermal transmittance fulfilment. The correlation between energy consumption and the climatic conditions is the base of the proposed method. The input data are seven climatic characteristics. Due to the sociocultural context of Latin America, the proposed method is estimated to have more possible acceptance and applications than other more complex methods, increasing the rate of buildings with an energy assessment. The results have demonstrated a high reliability in the prediction of the statistical models created, as the determination coe cient (R2) is nearly 1 for cooling and heating consumption

    A scalable parallel finite element framework for growing geometries. Application to metal additive manufacturing

    Get PDF
    This work introduces an innovative parallel, fully-distributed finite element framework for growing geometries and its application to metal additive manufacturing. It is well-known that virtual part design and qualification in additive manufacturing requires highly-accurate multiscale and multiphysics analyses. Only high performance computing tools are able to handle such complexity in time frames compatible with time-to-market. However, efficiency, without loss of accuracy, has rarely held the centre stage in the numerical community. Here, in contrast, the framework is designed to adequately exploit the resources of high-end distributed-memory machines. It is grounded on three building blocks: (1) Hierarchical adaptive mesh refinement with octree-based meshes; (2) a parallel strategy to model the growth of the geometry; (3) state-of-the-art parallel iterative linear solvers. Computational experiments consider the heat transfer analysis at the part scale of the printing process by powder-bed technologies. After verification against a 3D benchmark, a strong-scaling analysis assesses performance and identifies major sources of parallel overhead. A third numerical example examines the efficiency and robustness of (2) in a curved 3D shape. Unprecedented parallelism and scalability were achieved in this work. Hence, this framework contributes to take on higher complexity and/or accuracy, not only of part-scale simulations of metal or polymer additive manufacturing, but also in welding, sedimentation, atherosclerosis, or any other physical problem where the physical domain of interest grows in time

    Aeronautical Engineering. A continuing bibliography with indexes, supplement 156

    Get PDF
    This bibliography lists 288 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1982

    Recent progress in research on virtual sound barriers

    Full text link
    A virtual sound barrier is an active noise control system that uses arrays of loudspeakers and microphones to create a practical size of quiet zone in a noise environment just like an acoustic barrier but without blocking air and light. This technology can be used to reduce sound radiation from noise sources or to reduce noise level around one or few person heads in noisy environments in many industrial and domestic situations. This paper introduces the history, principle and design methods of the virtual sound barriers first, and then describes recent progress in research on the systems, especially the application on power transformer noise radiation control from an enclosure. The paper is concluded by the limitations and future direction discussions of the virtual sound barriers
    • …
    corecore