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Primal-dual variable neighborhood search for the simple plant-location problem
Copyright @ 2007 INFORMSThe variable neighborhood search metaheuristic is applied to the primal simple plant-location problem and to a reduced dual obtained by exploiting the complementary slackness conditions. This leads to (i) heuristic resolution of (metric) instances with uniform fixed costs, up to n = 15,000 users, and m = n potential locations for facilities with an error not exceeding 0.04%; (ii) exact solution of such instances with up to m = n = 7,000; and (iii) exact solutions of instances with variable fixed costs and up to m = n = 15, 000.This work is supported by NSERC Grant 105574-02; NSERC Grant OGP205041; and partly by the Serbian Ministry of Science, Project 1583
Testing collapse models with levitated nanoparticles: the detection challenge
We consider a nanoparticle levitated in a Paul trap in ultrahigh cryogenic
vacuum, and look for the conditions which allow for a stringent
noninterferometric test of spontaneous collapse models. In particular we
compare different possible techniques to detect the particle motion. Key
conditions which need to be achieved are extremely low residual pressure and
the ability to detect the particle at ultralow power. We compare three
different detection approaches based respectively on a optical cavity, optical
tweezer and a electrical readout, and for each one we assess advantages,
drawbacks and technical challenges
Analyzing the solutions of DEA through information visualization and data mining techniques: SmartDEA framework
Data envelopment analysis (DEA) has proven to be a useful tool for assessing efficiency or productivity of organizations, which is of vital practical importance in managerial decision making. DEA provides a significant amount of information from which analysts and managers derive insights and guidelines to promote their existing performances. Regarding to this fact, effective and methodologic analysis and interpretation of DEA solutions are very critical. The main objective of this study is then to develop a general decision support system (DSS) framework to analyze the solutions of basic DEA models. The paper formally shows how the solutions of DEA models should be structured so that these solutions can be examined and interpreted by analysts through information visualization and data mining techniques effectively. An innovative and convenient DEA solver, SmartDEA, is designed and developed in accordance with the proposed analysis framework. The developed software provides a DEA solution which is consistent with the framework and is ready-to-analyze with data mining tools, through a table-based structure. The developed framework is tested and applied in a real world project for benchmarking the vendors of a leading Turkish automotive company. The results show the effectiveness and the efficacy of the proposed framework
Gravitomagnetism and gravitational waves
After extensively reviewing general relativistic gravitomagnetism, both
historically and phenomenologically, we review in detail the so-called magnetic
components of gravitational waves (GWs), which have to be taken into account in
the context of the total response functions of interferometers for GWs
propagating from arbitrary directions. Following the more recent approaches of
this important issue, the analysis of such magnetic components will be reviewed
in both of standard General Theory of Relativity (GTR) and Scalar Tensor
Gravity. Thus, we show in detail that such a magnetic component becomes
particularly important in the high-frequency portion of the range of ground
based interferometers for GWs which arises from the two different theories of
gravity. Our reviewed results show that if one neglects the magnetic
contribution to the gravitational field of a GW, approximately 15% of the
potential observable signal could, in principle, be lost.Comment: To appear in the Special Issue of The Open Astronomy Journal "The Big
Challenge of Gravitational Waves, a New Window into the Universe", Editors
Christian Corda, Herman J. Mosquera Cuesta, Oswaldo Miranda and Theodore
Simo
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