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Realistic Solutions (realistic + solution)
Selected AbstractsA New Approach for Health Monitoring of Structures: Terrestrial Laser ScanningCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 1 2007H. S. Park Three-dimensional (3D) coordinates of a target structure acquired using TLS can have maximum errors of about 10 mm, which is insufficient for the purpose of health monitoring of structures. A displacement measurement model is presented to improve the accuracy of the measurement. The model is tested experimentally on a simply supported steel beam. Measurements were made using three different techniques: (1) linear variable displacement transducers (LVDTs), (2) electric strain gages, and (3) a long gage fiber optic sensor. The maximum deflections estimated by the TLS model are less than 1 mm and within 1.6% of those measured directly by LVDT. Although GPS methods allow measurement of displacements only at the GPS receiver antenna location, the proposed TLS method allows measurement of the entire building's or bridge's deformed shape, and thus a realistic solution for monitoring structures at both structure and member level. Furthermore, it can be used to create a 3D finite element model of a structural member or the entire structure at any instance of time automatically. Through periodic measurements of deformations of a structure or a structural member and performing inverse structural analyses with the measured 3D displacements, the health of the structure can be monitored continuously. [source] Path-generation of articulated mechanisms by shape and topology variations in non-linear truss representationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2005A. Kawamoto Abstract This paper presents studies on an optimization-based method for path-generation of articulated mechanisms. An extended truss ground-structure approach is taken in which both the shape and topology of the truss are designed using cross-sectional areas and nodal positions as design variables. This leads to a technique for simultaneous type and dimensional synthesis of articulated mechanisms. For the analysis part it is essential to control the mechanism configuration so that the mechanism remains within a given configuration space, thus stabilizing the optimization process and resulting in realistic solutions. This can be achieved by using the Levenberg,Marquardt method. The design method is illustrated by a number of design cases for both closed and open input and output paths. Copyright © 2005 John Wiley & Sons, Ltd. [source] High-Energy Density Capacitors Utilizing 0.7 BaTiO3,0.3 BiScO3 CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2009Hideki Ogihara A high, temperature-stable dielectric constant (,1000 from 0° to 300°C) coupled with a high electrical resistivity (,1012,·cm at 250°C) make 0.7 BaTiO3,0.3 BiScO3 ceramics an attractive candidate for high-energy density capacitors operating at elevated temperatures. Single dielectric layer capacitors were prepared to confirm the feasibility of BaTiO3,BiScO3 for this application. It was found that an energy density of about 6.1 J/cm3 at a field of 73 kV/mm could be achieved at room temperature, which is superior to typical commercial X7R capacitors. Moreover, the high-energy density values were retained to 300°C. This suggests that BaTiO3,BiScO3 ceramics have some advantages compared with conventional capacitor materials for high-temperature energy storage, and with further improvements in microstructure and composition, could provide realistic solutions for power electronic capacitors. [source] Optimal switchover times between two activities utilizing the same resourceNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 2 2002M. Karakul Abstract The "gold-mining" decision problem is concerned with the efficient utilization of a delicate mining equipment working in a number of different mines. Richard Bellman was the first to consider this type of a problem. The solution found by Bellman for the finite-horizon, continuous-time version of the problem with two mines is not overly realistic since he assumed that fractional parts of the same mining equipment could be used in different mines and this fraction could change instantaneously. In this paper, we provide some extensions to this model in order to produce more operational and realistic solutions. Our first model is concerned with developing an operational policy where the equipment may be switched from one mine to the other at most once during a finite horizon. In the next extension we incorporate a cost component in the objective function and assume that the horizon length is not fixed but it is the second decision variable. Structural properties of the optimal solutions are obtained using nonlinear programming. Each model and its solution is illustrated with a numerical example. The models developed here may have potential applications in other areas including production of items requiring the same machine or choosing a sequence of activities requiring the same resource. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 186,203, 2002; DOI 10.1002/nav.10008 [source] | ||||||||||