Regional Time Stepping for SPH

International audienceThis paper presents novel and efficient strategies to spatially adapt the amount of computational effort applied based on the local dynamics of a free surface flow, for classic weakly compressible SPH (WCSPH). Using a convenient and readily parallelizable block-based approach, different regions of the fluid are assigned differing time steps and solved at different rates to minimize computational cost. We demonstrate that our approach can achieve about two times speed-up over the standard method even in highly dynamic scenes

Buffered Count-Min Sketch on SSD: Theory and Experiments

Frequency estimation data structures such as the count-min sketch (CMS) have found numerous applications in databases, networking, computational biology and other domains. Many applications that use the count-min sketch process massive and rapidly evolving data sets. For data-intensive applications that aim to keep the overestimate error low, the count-min sketch becomes too large to store in available RAM and may have to migrate to external storage (e.g., SSD.) Due to the random-read/write nature of hash operations of the count-min sketch, simply placing it on SSD stifles the performance of time-critical applications, requiring about 4-6 random reads/writes to SSD per estimate (lookup) and update (insert) operation. In this paper, we expand on the preliminary idea of the buffered count-min sketch (BCMS) {[Eydi et al., 2017]}, an SSD variant of the count-min sketch, that uses hash localization to scale efficiently out of RAM while keeping the total error bounded. We describe the design and implementation of the buffered count-min sketch, and empirically show that our implementation achieves 3.7 x-4.7 x speedup on update and 4.3 x speedup on estimate operations compared to the traditional count-min sketch on SSD. Our design also offers an asymptotic improvement in the external-memory model over the original data structure: r random I/Os are reduced to 1 I/O for the estimate operation. For a data structure that uses k blocks on SSD, w as the word/counter size, r as the number of rows, M as the number of bits in the main memory, our data structure uses kwr/M amortized I/Os for updates, or, if kwr/M > 1, 1 I/O in the worst case. In typical scenarios, kwr/M is much smaller than 1. This is in contrast to O(r) I/Os incurred for each update in the original data structure. Lastly, we mathematically show that for the buffered count-min sketch, the error rate does not substantially degrade over the traditional count-min sketch. Specifically, we prove that for any query q, our data structure provides the guarantee: Pr[Error(q) >= n epsilon (1+o(1))] <= delta + o(1), which, up to o(1) terms, is the same guarantee as that of a traditional count-min sketch

Simulation et rendu temps-réel de nuages convectifs à l'échelle du paysage

This paper presents an efficient, physics-based procedural model for the real-time animation andvisualization of cumulus clouds at landscape size.We couple a coarse Lagrangian model of air parcels with a proceduralamplification using volumetric noise.Our Lagrangian model draws an aerology \ie the atmospheric physicsof hydrostatic atmosphere with thermodynamics transforms,augmented by a model of mixing between parcels and environment.In addition to the particle-particle interactions, we introduce particle-implicit environmentinteractions. In contrast to the usual fluid simulation, we thus do not needto sample the transparent environment, a key property forreal-time efficiency and scalability to large domains.Inheriting from the high-level physics of aerology, we also validate oursimulation by comparing it to predictive diagrams, and we show how the user caneasily control key aspects of the result such as the cloud base andtop altitude. Our model is thus fast, physical and controllable.Cet article présente un modèle temps-réel procédural basé sur laphysique pour l'animation et la visualisation temps réel de cumulus à l'échelle du paysage. Nous couplons un modèle Lagrangien basse-résolution de parcelles atmosphériques avec un modèle d'amplification procédurale à base de bruit volumique.Notre modèle Lagrangien s'appuie sur l'aérologie \ie la physique de l'atmosphère en équilibre hydrostatique avec transformations thermodynamiques,augmentée d'un modèle de mélange entre les parcelles et de l'environnement.En plus des interactions entre particules, nous introduisons lesinteractions entre les particules et l'environnement implicites. Contrairement à la simulation de fluides habituel, on n'a donc pas besoin d'échantillonner l'environnement transparent, une propriété clé pourl'accessibilité au temps réel et la scalabilité aux grandes étendues.Héritant de la physique à haut niveau de l'aérologie, nous validons notresimulation en la comparant aux diagrammes prédictifs, et nous montrons comment l'utilisateur peutcontrôler facilement les principaux aspects du résultat commel'altitude de la base et du haut des nuages. Notre modèle est donc rapide, physique et contrôlable

A WAY TO PREVENT THE PANDEMIC OUTBREAK OF nCOVID-19 IN INDIA

Not applicable because it is letter to edito

An efficient multi-resolution framework for high quality interactive rendering of massive point clouds using multi-way kd-trees

We present an efficient technique for out-of-core multi-resolution construction and high quality interactive visualization of massive point clouds. Our approach introduces a novel hierarchical level of detail (LOD) organization based on multi-way kd-trees, which simplifies memory management and allows control over the LOD-tree height. The LOD tree, constructed bottom up using a fast high-quality point simplification method, is fully balanced and contains all uniformly sized nodes. To this end, we introduce and analyze three efficient point simplification approaches that yield a desired number of high-quality output points. For constant rendering performance, we propose an efficient rendering-on-a-budget method with asynchronous data loading, which delivers fully continuous high quality rendering through LOD geo-morphing and deferred blending. Our algorithm is incorporated in a full end-to-end rendering system, which supports both local rendering and cluster-parallel distributed rendering. The method is evaluated on complex models made of hundreds of millions of point sample

An Emerging Trend in Tablet Technology:- Floating Tablets of Ranitidine HCl

The rationale of this research was to prepare a gastroretentive drug delivery system of Ranitidine HCL. Floating Drug delivery system used to target drug release in the stomach or to the upper part of the intestine. The oral delivery of Ranitidine is tested by preparing a non-disintegrating floating dosage form, which increase its absorption in the stomach by increasing the drug’s gastric residence time. The polymer PVC and Sodium bicarbonate was used as the gas–generating agents. Sodium bicarbonate causes the tablets to floats for more then 24hr. The prepared tablets were evaluated on their physicochemical properties and drug release characters. In-vitro release studies indicate that the Ranitidine release form the floating dosage form was uniform followed zero order release. A combination of sodium bicarbonate (70mg) and citric acid (15mg) was found to achieve Optimum in vitro buoyancy. The tablets with methocel K100 were found to float for longer duration of time as compared to formulations containing methocel K15M. The drug release from the tablets was sufficiently sustained.Keywords: Ranitidine; Floating tablets; Methoce

Correcting and complementing freeway traffic accident data using Mahalanobis distance based outlier detection

Arhivirana je ogromna količina podataka o prometu koji bi se mogli koristiti za dobivanje specifičnih podataka. Međutim, oni se u potpunosti ne koriste zbog nepostojanja točnih podataka o prometu (oznaka). U ovom radu poboljšavamo algoritam zasnovan na Mahalanobis udaljenosti za procjenu promjena toka prometa i otkrivanje nesreća i primjenjujemo ga kod ispravljanja i dopunjavanja informacija o nesreći. Algoritam za otkrivanje outliera (netipičnih vrijednosti) pruža točne podatke o vremenu događanja nesreće, trajanju i smjeru. Razvijamo i sustav s interaktivnim sučeljem korisnika u svrhu ostvarenja ovog postupka. Predlažu se tri načina za manipulaciju podacima. Najprije, za otkrivanje outliera u prometu predlažemo uporabu multi-metričkih podataka o prometu umjesto jedno metričkih. Nadalje, predlažemo praktičnu metodu za organizaciju prometnih podataka i evaluaciju organizacije Mahalanobis udaljenosti. Kao treće, dajemo opis opće metode za modifikaciju algoritama Mahalanobis udaljenosti kako bi se mogli ažurirati.A huge amount of traffic data is archived which can be used in data mining especially supervised learning. However, it is not being fully used due to lack of accurate accident information (labels). In this study, we improve a Mahalanobis distance based algorithm to be able to handle differential data to estimate flow fluctuations and detect accidents and use it to support correcting and complementing accident information. The outlier detection algorithm provides accurate suggestions for accident occurring time, duration and direction. We also develop a system with interactive user interface to realize this procedure. There are three contributions for data handling. Firstly, we propose to use multi-metric traffic data instead of single metric for traffic outlier detection. Secondly, we present a practical method to organise traffic data and to evaluate the organisation for Mahalanobis distance. Thirdly, we describe a general method to modify Mahalanobis distance algorithms to be updatable

Research Paper A Convenient One-Pot Synthesis of 2-Amino-4-Phenyl-1,8-Naphthyridine-3-Carbonitrile Derivatives

Abstract: A simple, efficient and one-pot procedure has been described for the synthesis of 2-amino-4-phenyl-1,8-naphthyridine-3-carbonitrile derivatives. A mixture of 2-amino pyridine, malononitrile and aromatic aldehydes were reacted in presence of catalytic amount of 3-nitrophenylboronic acid as catalyst at room temperature to produce 2-amino-4-phenyl-1,8-naphthyridine-3-carbonitriles. The mild reaction condition, short reaction time, high yield and simple experimental operation are the salient future of this method

Preparation and evaluation of mouth dissolving tablets of meloxicam

The aim of the present study was to develop evaluate mouth dissolving tablet of meloxicam. Drug delivery systems became sophisticated as pharmaceutical scientists acquire a better understanding of the physicochemical and biochemical parameters pertinent to their performance. Over the past three decades, mouth dissolving or orally disintegrating tablets have gained considerable attention as a preferred alternative to conventional tablets due to better patient compliance. The most preferrable route of drug administration (e.g. oral) is limited to drug candidate that show poor permeability across the gastric mucosa and those, which are sparingly soluble. A large majority of the new chemical entities and many new existing drug molecules are poorly soluble, thereby limiting their potential uses and increasing the difficulty of formulating bioavailable drug products,so lastlly the purpose of this study was to grow mouth dissolve tablets of Meloxicam. Meloxicam is a newer selective COX-1 inhibitor. These tablets were prepared by wet granulation procedure. The tablets were evaluated for % friability, wetting time and disintegration time. Sublimation of camphor from tablets resulted in better tablets as compared to the tablets prepared from granules that were exposing to vacuum. The systematic formulation approach helped in understanding the effect of formulation processing variables.Keywords: Mouth dissolving tablet; Maloxicam; Bioavailability; NSAI