Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
1.
Wirel Pers Commun ; 126(3): 2403-2423, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36033548

RESUMO

Artificial intelligence, specifically machine learning, has been applied in a variety of methods by the research group to transform several data sources into valuable facts and understanding, allowing for superior pattern identification skills. Machine learning algorithms on huge and complicated data sets, computationally expensive on the other hand, processing requires hardware and logical resources, such as space, CPU, and memory. As the amount of data created daily reaches quintillion bytes, A complex big data infrastructure becomes more and more relevant. Apache Spark Machine learning library (ML-lib) is a famous platform used for big data analysis, it includes several useful features for machine learning applications, involving regression, classification, and dimension reduction, as well as clustering and features extraction. In this contribution, we consider Apache Spark ML-lib as a computationally independent machine learning library, which is open-source, distributed, scalable, and platform. We have evaluated and compared several ML algorithms to analyze the platform's qualities, compared Apache Spark ML-lib against Rapid Miner and Sklearn, which are two additional Big data and machine learning processing platforms. Logistic Classifier (LC), Decision Tree Classifier (DTc), Random Forest Classifier (RFC), and Gradient Boosted Tree Classifier (GBTC) are four machine learning algorithms that are compared across platforms. In addition, we have tested general regression methods such as Linear Regressor (LR), Decision Tree Regressor (DTR), Random Forest Regressor (RFR), and Gradient Boosted Tree Regressor (GBTR) on SUSY and Higgs datasets. Moreover, We have evaluated the unsupervised learning methods like K-means and Gaussian Mixer Models on the data set SUSY and Hepmass to determine the robustness of PySpark, in comparison with the classification and regression models. We used "SUSY," "HIGGS," "BANK," and "HEPMASS" dataset from the UCI data repository. We also talk about recent developments in the research into Big Data machines and provide future research directions.

2.
Sensors (Basel) ; 11(3): 2875-84, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22163771

RESUMO

Wireless sensor networks require energy-efficient data transmission because the sensor nodes have limited power. A cluster-based routing method is more energy-efficient than a flat routing method as it can only send specific data for user requirements and aggregate similar data by dividing a network into a local cluster. However, previous clustering algorithms have some problems in that the transmission radius of sensor nodes is not realistic and multi-hop based communication is not used both inside and outside local clusters. As energy consumption based on clustering is dependent on the number of clusters, we need to know how many clusters are best. Thus, we propose an optimal number of cluster-heads based on multi-hop routing in wireless sensor networks. We observe that a local cluster made by a cluster-head influences the energy consumption of sensor nodes. We determined an equation for the number of packets to send and relay, and calculated the energy consumption of sensor networks using it. Through the process of calculating the energy consumption, we can obtain the optimal number of cluster-heads in wireless sensor networks.


Assuntos
Algoritmos , Redes de Comunicação de Computadores/instrumentação , Tecnologia sem Fio/instrumentação , Análise por Conglomerados , Modelos Teóricos , Termodinâmica
3.
Microsc Res Tech ; 84(4): 656-667, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33078468

RESUMO

Three-dimensional shape recovery is an important issue in the field of computer vision. Shape from Focus (SFF) is one of the passive techniques that uses focus information to estimate the three-dimensional shape of an object in the scene. Images are taken at multiple positions along the optical axis of the imaging device and are stored in a stack. In order to reconstruct the three dimensional shape of the object, the best-focused positions are acquired by maximizing the focus curves obtained via application of a focus measure operator. In this article, Deep Neural Network (DNN) is employed to extract the more accurate depth of each object point in the image stack. The size of each image in the stack is first reduced and then provided to the proposed DNN network to aggregate the shape. The initial shape is refined by applying a median filter, and later the reconstructed shape is sized back to original by utilizing bi-linear interpolation. The results are compared with commonly used focus measure operators by employing root mean squared error (RMSE), correlation, and image quality index (Q). Compared to other methods, the proposed SFF method using DNN shows higher precision and low computational time consumption.

4.
Diagnostics (Basel) ; 10(5)2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32392841

RESUMO

In this paper, we present an architecture of a personalized glucose monitoring system (PGMS). PGMS consists of both invasive and non-invasive sensors on a single device. Initially, blood glucose is measured invasively and non-invasively, to train the machine learning models. Then, paired data and corresponding errors are divided scientifically into six different clusters based on blood glucose ranges as per the patient's diabetic conditions. Each cluster is trained to build the unique error prediction model using an adaptive boosting (AdaBoost) algorithm. Later, these error prediction models undergo personalized calibration based on the patient's characteristics. Once, the errors in predicted non-invasive values are within the acceptable error range, the device gets personalized for a patient to measure the blood glucose non-invasively. We verify PGMS on two different datasets. Performance analysis shows that the mean absolute relative difference (MARD) is reduced exceptionally to 7.3% and 7.1% for predicted values as compared to 25.4% and 18.4% for measured non-invasive glucose values. The Clarke error grid analysis (CEGA) plot for non-invasive predicted values shows 97% data in Zone A and 3% data in Zone B for dataset 1. Moreover, for dataset 2 results echoed with 98% and 2% in Zones A and B, respectively.

5.
Diagnostics (Basel) ; 9(4)2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31717721

RESUMO

A magnetic resonance imaging (MRI) system is a complex, high cost, and long-life product. It is a widely known fact that performing a system reliability test of a MRI system during the development phase is a challenging task. The major challenges include sample size, high test cost, and long test duration. This paper introduces a novel approach to perform a MRI system reliability test in a reasonably acceptable time with one sample size. Our approach is based on an accelerated reliability growth test, which consists of test cycle made of a very high-energy time-of-flight three-dimensional (TOF3D) pulse sequence representing an actual hospital usage scenario. First, we construct a nominal day usage scenario based on actual data collected from an MRI system used inside the hospital. Then, we calculate the life-time stress based on a usage scenario. Finally, we develop an accelerated reliability growth test cycle based on a TOF3D pulse sequence that exerts highest vibration energy on the gradient coil and MRI system. We use a vibration energy model to map the life-time stress and reduce the test duration from 537 to 55 days. We use a Crow AMSAA plot to demonstrate that system design reaches its useful life after crossing the infant mortality phase.

6.
FEBS Lett ; 538(1-3): 65-70, 2003 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-12633854

RESUMO

Angiotensin I-converting enzymes (ACEs) are zinc metallopeptidases that cleave carboxy-terminal dipeptides from short peptide hormones. We have determined the crystal structures of AnCE, a Drosophila homolog of ACE, with and without bound inhibitors to 2.4 A resolution. AnCE contains a large internal channel encompassing the entire protein molecule. This substrate-binding channel is composed of two chambers, reminiscent of a peanut shell. The inhibitor and zinc-binding sites are located in the narrow bottleneck connecting the two chambers. The substrate and inhibitor specificity of AnCE appears to be determined by extensive hydrogen-bonding networks and ionic interactions in the active site channel. The catalytically important zinc ion is coordinated by the conserved Glu395 and histidine residues from a HExxH motif.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/metabolismo , Captopril/metabolismo , Lisinopril/metabolismo , Peptidil Dipeptidase A/metabolismo , Animais , Cristalografia por Raios X , Drosophila , Modelos Moleculares , Peptidil Dipeptidase A/química , Conformação Proteica , Especificidade por Substrato
7.
Nat Struct Biol ; 10(5): 342-8, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12715002

RESUMO

B-cell activating factor (BAFF) is a key regulator of B-lymphocyte development. Its biological role is mediated by the specific receptors BCMA, TACI and BAFF-R. We have determined the crystal structure of the extracellular domain of BAFF-R bound to BAFF at a resolution of 3.3 A. The cysteine-rich domain (CRD) of the BAFF-R extracellular domain adopts a beta-hairpin structure and binds to the virus-like BAFF cage in a 1:1 molar ratio. The conserved DxL motif of BAFF-R is located on the tip of the beta-turn and is indispensable in the binding of BAFF. The crystal structure shows that a unique dimeric contact occurs between the BAFF-R monomers in the virus-like cage complex. The extracellular domain of TACI contains two CRDs, both of which contain the DxL motif. Modeling of TACI-BAFF complex suggests that both CDRs simultaneously interact with the BAFF dimer in the virus-like cage.


Assuntos
Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Receptores do Fator de Necrose Tumoral/química , Receptores do Fator de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/química , Fator de Necrose Tumoral alfa/metabolismo , Sequência de Aminoácidos , Animais , Fator Ativador de Células B , Receptor do Fator Ativador de Células B , Sequência Conservada , Cristalografia por Raios X , Humanos , Imunoglobulina G/química , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Conformação Proteica , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA