138,992 research outputs found
Dual Hierarchy for Gravitational n-body
No full textThe n-body problem is the simulation of pair-wise interactions between n objects. This problem appears in many forms, with the classic example being the modeling of gravitational forces between point masses, necessary for cosmological simulations. Many approximation approaches have been devised to reduce the complexity of this problem.t-SNE is a data visualization method that requires repeatedly solving a variant of the n-body problem. A recent paper (An Efficient Dual-Hierarchy t-SNE Minimization, van de Ruit et. al.) proposes a novel algorithm that outperforms other t-SNE minimization methods on medium-scale datasets. The report proves the viability of a dual-traversal method that uses an embedding tree to emit forces and an independent field tree to collect forces. Because the embedding tree is a Linear-BVH and the field tree is an orthtree built to a fixed depth, the overall algorithm has linear complexity.This thesis demonstrates how the dual-tree approach can be adapted for gravitational n-body simulations. Following this, it measures the performance against similar implementations of other algorithms and shows that while the adapted Dual Hierarchy approach is faster than Barnes-Hut, it is outperformed by the Fast Multipole Method on realistic large-scale cosmological datasets.https://github.com/JacksonCampolattaro/n-body Git repository containing an implementation of the adapted Dual Hierarchy algorithm for Gravitational n-body, as well as implementations of several other common algorithms compared against during benchmarking.Computer Engineerin
Sajak-sajak Goenawan Mohamad dan sajak-sajak Taufik Ismail
No full textBuku Sajak-sajak Goenawan Mohamad dan Sajak-sajak Taufiq Ismail ini merupakan naskah laporan penelitian yang berjudul "Sajak-sajak Goenawan Mohamad dan Sajak-sajak Taufiq Ismail", yang disusun oleh tim peneliti Dami N. Toda dan Pamusuk Nasution dalam rangka kerja sama dengan Proyek Penelitian Bahasa dan Sastra Indonesia dan Daerah, Jakarta tahun 1975/1976
A note on mapping class group actions on derived categories
Get PDFLet Xnbe a cycle of n projective lines and Tn a symplectic torus with n punctures. Using the theory of spherical twists introduced by Seidel and Thomas, the author will define an action of the pure mapping class group of Tn on Db(Coh(Xn)). The motivation comes from homological mirror symmetry for degenerate elliptic curves, which was studied by the author with Treumann and Zaslow
Reactions of n,n-dibromobenzenesulfonamide with alcohols and mercaptans, 1971
Get PDFN,N-Dibromobenzenesulfonamide reacts with primary alcohols in a 1:2 molar ratio to yield the esters of the alcohols. The reaction is believed to proceed via a free radical mechanism to generate the reac-tive acylbromide species which then reacts with another mole of the alcohol to yield the ester as the final product. Benzyl alcohol and short chain primary alcohols give the corresponding aldehydes as side reactions. NNDBS reacts with secondary alcohols to give ketones and alpha bromoketones. No reaction takes place with tertiary alcohols. N,N-Dibromobenzenesulfonamide reacts with primary, secondary and tertiary mercaptans to yield the disulfide of the mercaptans in each case. When molecular bromine was used as the brominating agent, the alcohols did not react but the corresponding disulfide was obtained from each mercaptan
Experimental investigation into the effect of substrate clamping on the piezoelectric behaviour of thick-film PZT elements
No full textThis paper details an experimental investigation of the clamping effect associated with thick-film piezoelectric elements printed on a substrate. The clamping effect reduces the measured piezoelectric coefficient, d33, of the film. This reduction is due to the influence of the d31 component in the film when a deformation of the structure occurs, by either the direct or indirect piezoelectric effect. Theoretical analysis shows a reduction in the measured d33 of 62%, i.e. a standard bulk lead zirconate titanate (PZT)-5H sample with a manufacturer specified d33 of 593pC/N would fall to 227.8pC/N. To confirm this effect, the d33 coefficients of five thin bulk PZT-5H samples of 220µm thickness were measured before and after their attachment to a metallized 96% alumina substrate. The experimental results show a reduction in d33 of 74% from 529pC/N to 139pC/N. The theoretical analysis was then applied to existing University of Southampton thick-film devices. It is estimated that the measured d33 value of 131pC/N of the thick-film devices is the equivalent of an unconstrained d33 of 345pC/N
Certain Logarithmically N-Alternating Monotonic Functions Involving Gamma and q-Gamma Functions
No full textIn the paper, three basic properties of the logarithmically N-alternating
monotonic functions are established and the monotonicity results
of some functions involving the gamma and q-gamma functions, which are obtained
in [W. E. Clark and M. E. H. Ismail, Inequalities involving gamma and
psi functions, Anal. Appl. (Singap.) 1 (2003), no. 1, 129–140.], are generalized
to the logarithmically N-alternating monotonicity
An established preference for a conditioned stimulus associated with either sucrose or copulation in male rats subsequently shifts to a preference for a conditioned stimulus paired with cocaine self-administration
No full textIt is often assumed that a characteristic of drug addiction is a loss of interest in natural rewards concomitant with a heightened interest in drug rewards. To test this idea, we gave male rats a choice between a conditioned stimulus associated with a natural reward (sex or sucrose) and a conditioned stimulus associated with cocaine. In the first experiment, male rats were given five trials in which an odor (either lemon or almond) was associated with copulation to ejaculation with a sexually receptive female. Males were then given a choice between the odor-sex testing box and a neutral box (Day 1:15- min test). Rats showing a clear preference for the odor (n=10) then learned to self-administer cocaine in the presence of the other odor. After 3 cocaine sessions given on 3 consecutive days, they were given a choice test between the odor-sex and the odor-cocaine boxes (Day 10). The following day, there was an additional odor-sex pairing after which there were three additional days of odor-cocaine self-administration. Odor choice tests were given subsequently on Days 17, 24 and 38 without additional training. The odor preference of all rats did not shift immediately,but by day 38, 70% of the males chose the cocaine-paired odor. In Experiment 2, parallel results were observed in males (n=12) first trained to associate an odor with lever-pressing for sucrose pellets and then tested for the odor-sucrose box preference on Day 1. After training to self- administer cocaine in the presence of the second odor, rats developed a quick and consistent preference for the odor associated with cocaine. These results provide preliminary evidence that cocaine induces a preference shift in rats away from stimuli associated with natural rewards to stimuli paired with repeated drug self- administration. These experiments also demonstrate the effectiveness of the method for the further study of the phenomenon
On ternary monoid of hypersubstitutions of type ? = (n)
No full textA ternary monoid of hypersubstitutions of type ? = (n) is the set Hyp(n) of all hypersubstitutions of type ? = (n) with a ternary operation which satis es the associative law, and has the identity element ?id . For n = 2 , the idempotent and regular elements, the ideals of submonoids and some algebraic-properties of this monoid were studied by author. In this present paper, we study the algebraic-structural properties of Hyp(n), n > 2 and characterize the idempotent and regular elements. In particular, we describe the relationships between some submonoids of this monoid under the ideal of this submonoids
Correction to: A framework of genetic algorithm-based CNN on multi-access edge computing for automated detection of COVID-19 (The Journal of Supercomputing, (2022), 78, 7, (10250-10274), 10.1007/s11227-021-04222-4)
No full textIn this article the author name Walaa N. Ismail was incorrectly written as Walaa N Ismail. The affiliation details for Author Walaa N. Ismail were incorrectly given as ‘Faculty of Computers and Information, Minia University, Minia, Egypt’ but should have been ‘Faculty of Computers and Information, Minia University, Minia, 61519, Egypt’. Walaa N. Ismail at affiliation ‘Faculty of Computers and Information, Minia University, Minia, 61519, Egypt’ was missing from the author list on the last page. The original article has been corrected
After seven years in Key West, Florida, author John N. Cole learned to appreciat
No full textAfter seven years in Key West, Florida, author John N. Cole learned to appreciate Maine winters for their beauty and power
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