255 research outputs found

    A fast elitist non-dominated sorting genetic algorithm for multi-objective optimization: NSGA-II

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    Multi-objective evolutionary algorithms which use non-dominated sorting and sharing have been mainly criticized for their (i) O(MN3) computational complexity (where M is the number of objectives and N is the population size), (ii) non-elitism approach, and (iii) the need for specifying a sharing parameter. In this paper, we suggest a non-dominated sorting based multi-objective evolutionary algorithm (we called it the Non-dominated Sorting GA-II or NSGA-II) which alleviates all the above three difficulties. Specifically, a fast non-dominated sorting approach with O(MN2) computational complexity is presented. Second, a selection operator is presented which creates a mating pool by combining the parent and child populations and selecting the best (with respect to fitness and spread) N solutions. Simulation results on five difficult test problems show that the proposed NSGA-II, in most problems, is able to find much better spread of solutions and better convergence near the true Pareto-optimal front compared to PAES and SPEA-two other elitist multi-objective EAs which pay special attention towards creating a diverse Pareto-optimal front. Because of NSGA-II's low computational requirements, elitist approach, and parameter-less sharing approach, NSGA-II should find increasing applications in the years to come

    DEFAULT SELECTIVE MULTICAST ROUTE TO HANDLE HETEROGENEOUS NETWORK DESIGN

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    Techniques are described for a solution to traffic loss caused by heterogeneous network design with Ethernet Virtual Private Network (EVPN) multicast deployments. The techniques include detecting the presence of a multicast router behind a Bridge Domain and creating a default route to receive traffic from a remote source based on the detection

    Characterizing small depth and small space classes by operators of higher types

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    Motivated by the question of how to define an analog of interactive proofs in the setting of logarithmic time- and space-bounded computation, we study complexity classes defined in terms of operators quantifying over oracles. We obtain new characterizations of NC1, L, NL, NP, and NSC (the nondeterministic version of SC). In some cases, we prove that our simulations are optimal (for instance, in bounding the number of queries to the oracle)

    Cerebral Embolic Protection Devices: Current State of the Art

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    Transcatheter aortic valve replacement (TAVR) has become a first-line treatment for severe aortic stenosis with intermediate to high-risk population with its use increasingly expanding into younger and low-risk cohorts as well. Cerebrovascular events are one of the most serious consequential complications of TAVR, which increase morbidity and mortality. The most probable origin of such neurological events is embolic in nature and the majority occur in the acute phase after TAVR when embolic events are most frequent. Cerebral embolic protection devices have been designed to capture or deflect these emboli, reducing the risk of peri-procedural ischaemic events. They also carry the potential to diminish the burden of new silent ischemic lesions during TAVR. Our review explores different types of these device systems, their rationale, and the established clinical data

    Broadband X-ray properties of black holes GRS 1758-258 and 1E 1740.7-2942: AstroSat and NuSTAR results

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    We present the results on broadband X-ray properties of persistent black hole binaries GRS 1758βˆ’-258 and 1E 1740.7βˆ’-2942 using AstroSat, NuSTAR and Swift-XRT observations carried out during 2016βˆ’-2022. We perform spectral modeling of both sources after eliminating the contamination in their \textit{LAXPC} spectra from nearby X-ray sources. Preliminary spectral modelling using Comptonization and line emission (∼\sim 6.4 keV) models suggest that GRS 1758βˆ’-258 occupies both dim-soft state (kTbb=0.37Β±0.01kT_{bb}=0.37\pm0.01 keV, Ξ“βˆΌ5.9\Gamma\sim5.9, Lbol=1L_{bol}=1 % of Eddington luminosity LEdd_{Edd}) and hard state (Ξ“=1.64βˆ’2.22\Gamma=1.64-2.22, kTekT_{e}=4βˆ’-45 keV, LbolL_{bol}=1βˆ’-5 % LEdd_{Edd}) that requires a multi-colour disc blackbody model (kTin=0.54Β±0.01kT_{in}=0.54\pm0.01 keV) occasionally. 1E 1740.7βˆ’-2942 instead is found only in hard state (Ξ“\Gamma=1.67βˆ’-2.32, kTekT_{e}=5βˆ’-16 keV, LbolL_{bol}=1βˆ’-2 % LEdd_{Edd}). Reflection properties of both sources are studied by applying relativistic reflection model RELXILL to the broadband spectra. Our results from \textit{AstroSat} and \textit{NuSTAR} consistently unveiled the presence of a Comptonizing region along with an ionized reflection region (ionization parameter logΞΎlog\xi=2.7βˆ’-3.8 and 2.7βˆ’-4.7 erg cm sβˆ’1^{-1} in GRS 1758βˆ’-258 and 1E 1740.7βˆ’-2942 respectively) in both sources. Reflection modeling revealed GRS 1758βˆ’-258 to have a high metal abundance (Afe=3.9βˆ’0.3+0.4A_{fe}=3.9^{+0.4}_{-0.3} times solar metal abundance) and inclination angle (ii) of 61Β±2∘61\pm2^{\circ}. In case of 1E 1740.7βˆ’-2942, ii is constrained to be 55Β±1∘55\pm1^{\circ}. Finally, we discuss the implication of our findings in the context of accretion dynamics by comparing our results with the previous studies.Comment: Accepted for publication in MNRA
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