36,115 research outputs found

    Speculative Approximations for Terascale Analytics

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    Model calibration is a major challenge faced by the plethora of statistical analytics packages that are increasingly used in Big Data applications. Identifying the optimal model parameters is a time-consuming process that has to be executed from scratch for every dataset/model combination even by experienced data scientists. We argue that the incapacity to evaluate multiple parameter configurations simultaneously and the lack of support to quickly identify sub-optimal configurations are the principal causes. In this paper, we develop two database-inspired techniques for efficient model calibration. Speculative parameter testing applies advanced parallel multi-query processing methods to evaluate several configurations concurrently. The number of configurations is determined adaptively at runtime, while the configurations themselves are extracted from a distribution that is continuously learned following a Bayesian process. Online aggregation is applied to identify sub-optimal configurations early in the processing by incrementally sampling the training dataset and estimating the objective function corresponding to each configuration. We design concurrent online aggregation estimators and define halting conditions to accurately and timely stop the execution. We apply the proposed techniques to distributed gradient descent optimization -- batch and incremental -- for support vector machines and logistic regression models. We implement the resulting solutions in GLADE PF-OLA -- a state-of-the-art Big Data analytics system -- and evaluate their performance over terascale-size synthetic and real datasets. The results confirm that as many as 32 configurations can be evaluated concurrently almost as fast as one, while sub-optimal configurations are detected accurately in as little as a 1/20th1/20^{\text{th}} fraction of the time

    Multidisciplinary Design Optimization For Multi Purpose Design Of Truck

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    Multidisciplinary Design Optimization (MOO) problem are often are encountered in many industrial areas and aspect. MOO refers to the optimization of systems of subsystem (disciplines). The optimization of the full system is often reduced to hierarchy of optimizations at subsystem and system levels. Multidisciplinary Design Optimization is a body of methods and techniques for performing the above optimization so as to balance the design considerations at the system and detail levels. This paper will be presents an application of MOO for multi purpose design of truck, case study in Toyota Dyna. That body of truck can be used for some purpose, example for fluid tanker, mixer truck, bulk and box truck and other purpose. The successful design requires harmonization of a number of objectives and con5traint. However, dimensionality of such optimization and the complexity and expense of the underlying analysis suggest a decomposition approach to enable concurrent execution of smaller and more manageable task. We identify that the fundamental approach to modeling the design depend on lumped mass, vehicle fixed coordin2te system, motion variable, earth fixed coordinate system, euler angles, and force. The master problem for multi purpose design of body truck is to maximize the contain capacity, with design variable are length, wide and high of the body. The sub problem are minimize the centrifugal force, roll threshold and suspension. The result of this paper will be giving the optimum condition of the body dimension and helpful the design to reduce time for design. Finally, quality of product will be increase, reducing cost and thereby being competitive

    Multiscale, thermomechanical topology optimization of self-supporting cellular structures for porous injection molds

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    Purpose This paper aims to establish a multiscale topology optimization method for the optimal design of non-periodic, self-supporting cellular structures subjected to thermo-mechanical loads. The result is a hierarchically complex design that is thermally efficient, mechanically stable and suitable for additive manufacturing (AM). Design/methodology/approach The proposed method seeks to maximize thermo-mechanical performance at the macroscale in a conceptual design while obtaining maximum shear modulus for each unit cell at the mesoscale. Then, the macroscale performance is re-estimated, and the mesoscale design is updated until the macroscale performance is satisfied. Findings A two-dimensional Messerschmitt Bolkow Bolhm (MBB) beam withstanding thermo-mechanical load is presented to illustrate the proposed design method. Furthermore, the method is implemented to optimize a three-dimensional injection mold, which is successfully prototyped using 420 stainless steel infiltrated with bronze. Originality/value By developing a computationally efficient and manufacturing friendly inverse homogenization approach, the novel multiscale design could generate porous molds which can save up to 30 per cent material compared to their solid counterpart without decreasing thermo-mechanical performance. Practical implications This study is a useful tool for the designer in molding industries to reduce the cost of the injection mold and take full advantage of AM

    Novel CMOS RFIC Layout Generation with Concurrent Device Placement and Fixed-Length Microstrip Routing

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    With advancing process technologies and booming IoT markets, millimeter-wave CMOS RFICs have been widely developed in re- cent years. Since the performance of CMOS RFICs is very sensi- tive to the precision of the layout, precise placement of devices and precisely matched microstrip lengths to given values have been a labor-intensive and time-consuming task, and thus become a major bottleneck for time to market. This paper introduces a progressive integer-linear-programming-based method to gener- ate high-quality RFIC layouts satisfying very stringent routing requirements of microstrip lines, including spacing/non-crossing rules, precise length, and bend number minimization, within a given layout area. The resulting RFIC layouts excel in both per- formance and area with much fewer bends compared with the simulation-tuning based manual layout, while the layout gener- ation time is significantly reduced from weeks to half an hour.Comment: ACM/IEEE Design Automation Conference (DAC), 201
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