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991.
Vijay Nair K. C. Sheela K. V. Radhakrishnan A. U. Vinod J. Somarajan Nair C. Rajesh P. M. Treesa 《Journal of heterocyclic chemistry》2000,37(3):659-668
The reactivity of o‐quinones and other 1,2‐diones towards a variety of dipolar species viz‐, nitrile oxides, carbonyl ylides, betaines and mesoionic compounds has been investigated. In most cases, these reactions occur with the participation of C=O group as the dipolarophile leading to the synthesis of novel heterocyclic compounds. 相似文献
992.
T Öncan S N Kabadi K P K Nair A P Punnen 《The Journal of the Operational Research Society》2008,59(3):388-398
In this paper, we propose a general paradigm to design very large-scale neighbourhood search algorithms for generic partitioning-type problems. We identify neighbourhoods of exponential size, called matching neighbourhoods, comprised of the union of a class of exponential neighbourhoods. It is shown that these individual components of the matching neighbourhood can be searched in polynomial time, whereas searching the matching neighbourhood is NP-hard. Matching neighbourhood subsumes a well-known class of exponential neighbourhoods called cyclic-exchange neighbourhoods. Our VLSN algorithm is implemented for two special cases of the partitioning problem; the covering assignment problem and the single source transportation problem. Encouraging experimental results are also reported. 相似文献
993.
994.
N. Unnikrishnan Nair K. K. Sudheesh 《Annals of the Institute of Statistical Mathematics》2008,60(3):591-603
In the present paper a general theorem that links characterizations of discrete life distributions based on relationship between
failure rate and conditional expectations with those in terms of Chernoff-type inequalities is proposed. Exact expression
for lower bounds to the variance is calculated for distributions belonging to the modified power series family, Ord family
and mixture geometric models. It is shown that the bounds obtained here contain the Cramer–Rao and Chapman–Robbins inequalities
as special cases. An application of the results to real data is also provided. 相似文献
995.
Characterizations of multivariate life distributions 总被引:1,自引:0,他引:1
N. Unnikrishnan Nair 《Journal of multivariate analysis》2008,99(9):2096-2107
Characterizations of multivariate distributions has been a topic of great interest in applied statistics literature for the last three decades. In this paper, we develop characterizations of multivariate lifetime distributions by relationship between multivariate failure rates (reversed failure rates) and the left (right) truncated expectations of functions of random variables. We, then, discuss the application of the results to derive a multivariate Stein type identity. 相似文献
996.
S. P. Nair P. M. Pardalos V. A. Yatsenko 《Journal of Optimization Theory and Applications》2007,134(3):533-547
In this paper, we analyze various control algorithms that have been proposed for controlling spatiotemporal chaos in a globally
coupled map lattice (CML) system. We reformulate the choice of feedback parameters in such systems as a constrained optimization
problem and provide numerical and experimental results on the choice of optimal parameters for controlling the mean global
Lyapunov exponent of a lattice. Finally, we propose a scheme to use this optimization technique to solve a learning problem
in which such a CML system can be used to emulate the dynamics of an epileptic brain.
This work was supported by NIH-NIBIB and CRDF grants. 相似文献
997.
Eliane Maria Loiola Nair Maria Maia de Abreu Paulo Oswaldo Boaventura-Netto Peter Hahn Tania Querido 《European Journal of Operational Research》2007
The quadratic assignment problem (QAP), one of the most difficult problems in the NP-hard class, models many real-life problems in several areas such as facilities location, parallel and distributed computing, and combinatorial data analysis. Combinatorial optimization problems, such as the traveling salesman problem, maximal clique and graph partitioning can be formulated as a QAP. In this paper, we present some of the most important QAP formulations and classify them according to their mathematical sources. We also present a discussion on the theoretical resources used to define lower bounds for exact and heuristic algorithms. We then give a detailed discussion of the progress made in both exact and heuristic solution methods, including those formulated according to metaheuristic strategies. Finally, we analyze the contributions brought about by the study of different approaches. 相似文献
998.
Stereoselective synthesis of highly functionalized tetrahydrofurans via the 1,3-dipolar cycloaddition reaction of acyclic carbonyl ylides to activated alkenes is described. 相似文献
999.
In the search for silicon technology compatible substrate for III-nitride epitaxy, we present a proof-of-concept for forming epitaxial SiC layer on Si(1 1 1). A C/Si interface formed by ion sputtering is exposed to 100-1500 eV Ar+ ions, inducing a chemical reaction to form SiC, as observed by core-level X-ray photoelectron spectroscopy (XPS). Angle dependent XPS studies shows forward scattering feature that manifest the epitaxial SiC layer formation, while the valence band depicts the metal to insulator phase change. 相似文献
1000.
Vedanth Nair Benjamin Wilde Benjamin Emerson Tim Lieuwen 《Proceedings of the Combustion Institute》2019,37(4):5173-5180
This study explores the effect of heat release on the growth of the shear layer vortical structures in a reacting jet in crossflow. Jets composed of mixtures of hydrogen, helium and nitrogen were used to independently vary the momentum flux ratio (J), jet to crossflow density ratio (S) and heat release. Velocity fields were obtained from 10?kHz high-speed stereoscopic particle image velocimetry (SPIV) and regions of elevated temperature/combustion products from simultaneous OH planar laser induced fluorescence (OH-PLIF). The shear layer vortices (SLV) originating from instabilities in the windward and leeward shear layers were identified using vortex identification indicator functions in order to track their spatial location and strength. The results show that the asymmetries in shear layer strength between the windward and leeward shear layers are dependent primarily on J, for both reacting and non-reacting flow-fields. The SLV growth rate dependencies on J and S is found to match trends noted by previous studies for non-reacting jets, where SLV growth rates increase with degree of global instability of the JICF. Heat release is also shown to suppress the SLV growth rates relative to non-reacting cases with the same jet parameters. Related to this point, the degree of lifting of the flame also has a significant impact on SLV growth. As flame lifting is directly related to autoignition times, this point shows strong coupling between kinetic rates and jet hydrodynamic stability. 相似文献