1,989 research outputs found
An adaptive NARX neural network approach for financial time series prediction
No full textThere has been increasing interest in the application of neural networks to the field of finance. Several experiments have been carried out stating the success of neural networks for time series prediction.
Most of the existing systems recommend single neural network architecture to be used for a particular time series. Our experiments have shown that a fixed architecture may not be the best approach across different time horizons. The thesis proposes a new methodology where multiple NARX (nonlinear autoregressive network with exogenous inputs) networks with different architectures are generated and evaluated before the beginning of a new time horizon. A network is selected from this set and employed to make predictions. This selection is based on past datasets only -- making the system completely applicable to real world scenarios.
A framework of functions was built in MATLAB® to customize the Neural Network Toolbox ® for financial applications. This framework provides for all the basic functions required by a financial neural network system. An adaptive system that uses technical indicators and some external time series as inputs was built. Different rules were developed and tested for selecting the best performing neural networks.
The new approach was tested on 5 currencies and the gold series. Our results show that high realized values of returns in the past, along with generalization is the best parameter to select a network for the future. A system with adaptive approach performs better than one with a fixed architecture. Our adaptive system out performed not only the fixed architectures but also other benchmarks like technical indicators, linear regression and baseline buy or sell strategies.M.S.Includes bibliographical references (p. 80-82)
Plant-in-chip: Microfluidic system for studying root growth and pathogenic interactions in Arabidopsis
No full textWe report a microfluidic platform for the hydroponic growth of Arabidopsis plants with high-resolution visualization of root development and root-pathogen interactions. The platform comprises a set of parallel microchannels with individual input/output ports where 1-day old germinated seedlings are initially placed. Under optimum conditions, a root system grows in each microchannel and its images are recorded over a 198-h period. Different concentrations of plant growth media show different root growth characteristics. Later, the developed roots are inoculated with two plant pathogens (nematodes and zoospores) and their physicochemical interactions with the live root systems are observed.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Parashar, Archana, and Santosh Pandey. "Plant-in-chip: Microfluidic system for studying root growth and pathogenic interactions in Arabidopsis." Applied Physics Letters 98, no. 26 (2011): 263703, and may be found at DOI: 10.1063/1.3604788. Copyright 2011 American Institute of Physics. Posted with permission
Ishair: Importance sampling for hair scattering
No full textWe present an importance sampling method for the bidirectional scattering distribution function (bsdf) of hair. Our method is based on the multi-lobe hair scattering model presented by Sadeghi et al. . We reduce Noise by drawing samples from a distribution that approximates the bsdf well. Our algorithm is efficient and Easy to implement, since the sampling process requires only the evaluation of a few analytic functions, with no Significant memory overhead or need for precomputation. We tested our method in a research raytracer and a Production renderer based on micropolygon rasterization. We show significant improvements for rendering direct Illumination using multiple importance sampling and for rendering indirect illumination using path tracing. © 2012 The Author(s)
Frequency upconversion in Er3+ doped tungsten tellurite glass containing Ag nanoparticles
No full textUnidirectional, electrotactic-response valve for Caenorhabditis elegans in microfluidic devices
No full textWe report a nematode electrotactic-response valve (NERV) to control the locomotion of Caenorhabditis elegans (C. elegans) in microfluidic devices. This nonmechanical, unidirectional valve is based on creating a confined region of lateral electric field that is switchable and reversible. We observed that C. elegans do not prefer to pass through this region if the field lines are incident to its forward movement. Upon reaching the boundary of the NERV, the incident worms partially penetrate the field region, pull back, and turn around. The NERV is tested on three C. elegans mutants: wild-type (N2), lev-8, and acr-16.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Carr, John A., Roy Lycke, Archana Parashar, and Santosh Pandey. "Unidirectional, electrotactic-response valve for Caenorhabditis elegans in microfluidic devices." Applied Physics Letters 98, no. 14 (2011): 143701, and may be found at DOI: 10.1063/1.3570629. Copyright 2011 American Institute of Physics. Posted with permission
Microfluidics-enabled method to identify modes of Caenorhabditis elegans paralysis in four anthelmintics
No full textThe discovery of new drugs is often propelled by the increasing resistance of parasites to existing drugs and the availability of better technology platforms. The area of microfluidics has provided devices for faster screening of compounds, controlled sampling/sorting of whole animals, and automated behavioral pattern recognition. In most microfluidic devices, drug effects on small animals (e.g., Caenorhabditis elegans) are quantified by an end-point, dose response curve representing a single parameter (such as worm velocity or stroke frequency). Here, we present a multi-parameter extraction method to characterize modes of paralysis in C. elegans over an extended time period. A microfluidic device with real-time imaging is used to expose C. elegans to four anthelmintic drugs (i.e., pyrantel, levamisole, tribendimidine, and methyridine). We quantified worm behavior with parameters such as curls per second, types of paralyzation, mode frequency, and number/duration of active/immobilization periods. Each drug was chosen at EC75 where 75% of the worm population is responsive to the drug. At equipotent concentrations, we observed differences in the manner with which worms paralyzed in drug environments. Our study highlights the need for assaying drug effects on small animal models with multiple parameters quantified at regular time points over an extended period to adequately capture the resistance and adaptability in chemical environments.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Lycke, Roy, Archana Parashar, and Santosh Pandey. "Microfluidics-enabled method to identify modes of Caenorhabditis elegans paralysis in four anthelmintics." Biomicrofluidics 7, no. 6 (2013): 064103, and may be found at DOI: 10.1063/1.4829777. Copyright 2013 AIP Publishing LLC. Posted with permission
Componenti Avanzati GCM/SCA
No full textQuesta tesi fa prima una panoramica sullo stato dell'arte esistente in merito ai componenti software usati in ambito Grid e poi cerca di implementare un componente GCM: un behavioural skeleton task-farm usando come runtime di supporto SCA al fine di dimostrare la fattibilità e le presetazioni del behavioral skeleton sotto tale piattaforma
Poor quality drugs: grand challenges in high throughput detection, countrywide sampling, and forensics in developing countries.
No full textThroughout history, poor quality medicines have been a persistent problem, with periodical crises in the supply of antimicrobials, such as fake cinchona bark in the 1600s and fake quinine in the 1800s. Regrettably, this problem seems to have grown in the last decade, especially afflicting unsuspecting patients and those seeking medicines via on-line pharmacies. Here we discuss some of the challenges related to the fight against poor quality drugs, and counterfeits in particular, with an emphasis on the analytical tools available, their relative performance, and the necessary workflows needed for distinguishing between genuine, substandard, degraded and counterfeit medicines
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