20,403 research outputs found

    Aerodynamic Optimization of High-Speed Trains Nose using a Genetic Algorithm and Artificial Neural Network

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    An aerodynamic optimization of the train aerodynamic characteristics in term of front wind action sensitivity is carried out in this paper. In particular, a genetic algorithm (GA) is used to perform a shape optimization study of a high-speed train nose. The nose is parametrically defined via Bézier Curves, including a wider range of geometries in the design space as possible optimal solutions. Using a GA, the main disadvantage to deal with is the large number of evaluations need before finding such optimal. Here it is proposed the use of metamodels to replace Navier-Stokes solver. Among all the posibilities, Rsponse Surface Models and Artificial Neural Networks (ANN) are considered. Best results of prediction and generalization are obtained with ANN and those are applied in GA code. The paper shows the feasibility of using GA in combination with ANN for this problem, and solutions achieved are included

    Synthesis of Arbitrary Quantum Circuits to Topological Assembly: Systematic, Online and Compact

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    It is challenging to transform an arbitrary quantum circuit into a form protected by surface code quantum error correcting codes (a variant of topological quantum error correction), especially if the goal is to minimise overhead. One of the issues is the efficient placement of magic state distillation sub circuits, so-called distillation boxes, in the space-time volume that abstracts the computation's required resources. This work presents a general, systematic, online method for the synthesis of such circuits. Distillation box placement is controlled by so-called schedulers. The work introduces a greedy scheduler generating compact box placements. The implemented software, whose source code is available online, is used to illustrate and discuss synthesis examples. Synthesis and optimisation improvements are proposed

    FMCW rail-mounted SAR: Porting spotlight SAR imaging from MATLAB to FPGA

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    In this work, a low-cost laptop-based radar platform derived from the MIT open courseware has been implemented. It can perform ranging, Doppler measurement and SAR imaging using MATLAB as the processor. In this work, porting the signal processing algorithms onto a FPGA platform will be addressed as well as differences between results obtained using MATLAB and those obtained using the FPGA platform. The target FPGA platforms were a Virtex6 DSP kit and Spartan3A starter kit, the latter was also low-cost to further reduce the cost for students to access radar technology

    Ono: an open platform for social robotics

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    In recent times, the focal point of research in robotics has shifted from industrial ro- bots toward robots that interact with humans in an intuitive and safe manner. This evolution has resulted in the subfield of social robotics, which pertains to robots that function in a human environment and that can communicate with humans in an int- uitive way, e.g. with facial expressions. Social robots have the potential to impact many different aspects of our lives, but one particularly promising application is the use of robots in therapy, such as the treatment of children with autism. Unfortunately, many of the existing social robots are neither suited for practical use in therapy nor for large scale studies, mainly because they are expensive, one-of-a-kind robots that are hard to modify to suit a specific need. We created Ono, a social robotics platform, to tackle these issues. Ono is composed entirely from off-the-shelf components and cheap materials, and can be built at a local FabLab at the fraction of the cost of other robots. Ono is also entirely open source and the modular design further encourages modification and reuse of parts of the platform

    Application Of Dynamic Correlation Technique And Model Updating On Truck Chassis

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    Truck chassis is a major component in a vehicle system. It is often identified for refinement in order to develop vehicles with reduced cost and weight. Nowadays the process of chassis design in the automotive industry has been significantly refined with the high capabilities of advanced computer aided design and engineering tools,. The application of FEA such as structural modification and optimization is used to reduce component complexity, weight and subsequently cost. Because the level of model complexity can be high, the opportunity for error can also be high. For this reason, some form of model verification is needed before design decisions made in the FEA environment can be implemented in production. This paper looks into the application of dynamic correlation techniques for verification of the FEA models of truck chassis. The dynamic characteristics of truck chassis such as the natural frequency and mode shape were determined using finite element method. Experimental modal analysis was carried out to validate the FE models. Initial results from both analysis show that the truck chassis experienced 1st torsion mode for 1st natural frequency, 1st bending mode for 2nd natural frequency, 2nd torsion mode for 3rd natural frequency and 2nd bending mode for 4th natural frequency. However there is a small discrepancy in terms of frequency. Thus, the model updating of truck chassis model was done by adjusting the selective properties such as Modulus Young and Poisson ratio in order to get better agreement in the natural frequency between both analysis. Finally, the modifications of the updated FE truck chassis model was suggested such as by considering adding the stiffener. The purpose is to reduce the vibration as well as to improve the strength of the truck chassis

    A tolerance analysis and optimization methodology: the combined use of 3D CAT, a dimensional hierarchization matrix and an optimization algorithm

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    We propose a methodology in this study for the analysis and the optimization of assembly tolerances. A combination of three components, it involves the use of 3D CAT software, a table referred to as a “dimensional hierarchization matrix” and a tolerance optimization algorithm. The Antolin Group, a Spanish multinational in the automobile components sector, employs this system to optimize tolerance values and to reduce manufacturing costs. The matrix was designed to enable easy identification, in a single table, of all requirements that fail to meet the specifications in the different approximations, prior to the definition of the dimensional and the geometric tolerances that comply with the functional requirements, and to identify which tolerances contribute most to variations in all of the functional conditions of the mechanism. Through its different iterations, this matrix allows us to see which of the tolerances should first be modified to optimize the design requirement specifications. A tolerance optimization algorithm was also defined, which functions with the data from the dimensional hierarchization matrix

    Analysis of shear test method for composite laminates

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    An elastic plane stress finite element analysis of the stress distributions in four flat test specimens for in-plane shear response of composite materials subjected to mechanical or thermal loads is presented. The shear test specimens investigated include: slotted coupon, cross beam, losipescu, and rail shear. Results are presented in the form of normalized shear contour plots for all three in-plane stess components. It is shown that the cross beam, losipescu, and rail shear specimens have stress distributions which are more than adequate for determining linear shear behavior of composite materials. Laminate properties, core effects, and fixture configurations are among the factors which were found to influence the stress distributions
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