scholarly journals Artificial neural networks for solving elliptic differential equations with boundary layer

Author(s):  
Dongfang Yuan ◽  
Wenhui Liu ◽  
Yongbin Ge ◽  
Guimei Cui ◽  
Lin Shi ◽  
...  

In this paper, we consider the artificial neural networks for solving the differential equation with boundary layer, in which the gradient of the solution changes sharply near the boundary layer. The solution of the boundary layer problems poses a huge challenge to both traditional numerical methods and artificial neural network methods. By theoretical analyzing the changing rate of the weights of first hidden layer near the boundary layer, a mapping strategy is added in traditional neural network to improve the convergence of the loss function. Numerical examples are carried out for the 1D and 2D convection-diffusion equation with boundary layer. The results demonstrate that the modified neural networks significantly improve the ability in approximating the solutions with sharp gradient.

2020 ◽  
Vol 8 (4) ◽  
pp. 469
Author(s):  
I Gusti Ngurah Alit Indrawan ◽  
I Made Widiartha

Artificial Neural Networks or commonly abbreviated as ANN is one branch of science from the field of artificial intelligence which is often used to solve various problems in fields that involve grouping and pattern recognition. This research aims to classify Letter Recognition datasets using Artificial Neural Networks which are weighted optimally using the Artificial Bee Colony algorithm. The best classification accuracy results from this study were 92.85% using a combination of 4 hidden layers with each hidden layer containing 10 neurons.


2018 ◽  
Vol 7 (2.13) ◽  
pp. 402
Author(s):  
Y Yusmartato ◽  
Zulkarnain Lubis ◽  
Solly Arza ◽  
Zulfadli Pelawi ◽  
A Armansah ◽  
...  

Lockers are one of the facilities that people use to store stuff. Artificial neural networks are computational systems where architecture and operations are inspired by the knowledge of biological neurons in the brain, which is one of the artificial representations of the human brain that always tries to stimulate the learning process of the human brain. One of the utilization of artificial neural network is for pattern recognition. The face of a person must be different but sometimes has a shape similar to the face of others, because the facial pattern is a good pattern to try to be recognized by using artificial neural networks. Pattern recognition on artificial neural network can be done by back propagation method. Back propagation method consists of input layer, hidden layer and output layer.  


TEM Journal ◽  
2020 ◽  
pp. 1320-1329
Author(s):  
Kostadin Yotov ◽  
Emil Hadzhikolev ◽  
Stanka Hadzhikoleva

How can we determine the optimal number of neurons when constructing an artificial neural network? This is one of the most frequently asked questions when working with this type of artificial intelligence. Experience has brought the understanding that it takes an individual approach for each task to specify the number of neurons. Our method is based on the requirement of algorithms looking for a minimum of functions of type 𝑺􁈺𝒛􁈻 􀵌 Σ 􁈾𝝋𝒊 𝒎 􁈺𝒛 􁈻􁈿𝟐 𝒊􀭀𝟏 that satisfy the inequality 𝒑 􀵑 𝒎, where p is the dimensionality of the argument z, and m is the number of functions. Formulas for an upper limit of the required neurons are proposed for networks with one hidden layer and for networks with r hidden layers with an equal number of neurons.


2018 ◽  
Vol 5 (5) ◽  
pp. 597
Author(s):  
Nur Yanti ◽  
Fathur Zaini Rachman ◽  
Nurwahidah Jamal ◽  
Era Purwanto ◽  
Fachrurozy Fachrurozy

<p class="Abstrak"> </p><p class="Abstrak">Sistem keamanan yang bertujuan sebagai sistem monitoring pada <em>smart home</em> seperti memonitoring pengguna laboratorium, perpustakaan, atau ruangan penyimpanan dan peminjaman peralatan praktek di program studi suatu kampus, ruang penyimpanan senjata, hingga rumah tinggal, memerlukan sekuritas yang handal untuk memudahkan identifikasi pengguna ruangan atau pencegahan dari tindak pencurian, maka dirancang sistem monitoring melalui pengenalan citra sidik jari menggunakan sensor ZFM60, jaringan syaraf tiruan dan MySQL. Tujuannya agar di dapat pola yang relevan dari citra dan mengeliminasi informasi atau variabel yang tidak relevan. Metode yang digunakan yaitu <em>experimental</em>, terdiri dari pengumpulan data sidik jari, perancangan sistem pengolahan citra, pembuatan dan pengujian <em>hardware</em> dan <em>software</em>, serta implementasi sistem. Hasil proses pengenalan atau klarifikasi citra sidik jari melalui GUI Matlab, nilai <em>error</em> hasil pengolahan dan pelatihan citra sidik jari dengan jaringan syaraf tiruan, digunakan sebagai ciri citra dan disimpan sebagai <em>data base</em> pada MySQL, kemudian dibandingkan dengan nilai <em>error</em> citra sidik jari baru yang di klarifikasi. Nilai citra yang dapat dikenali berada diantara -0,0005 hingga 0,0005, diluar batas tersebut merupakan citra yang tidak dikenali. Selisih (nilai <em>error</em>) antara ciri citra yang tersimpan pada <em>data base</em> dan ciri citra yang diklarifikasi menghasilkan nilai <em>error </em>yang kecil yaitu &lt; 0.0005, menunjukkan jaringan syaraf tiruan <em>backpropagation</em> handal diimplementasikan pada pengenalan sidik jari untuk melatih pola citra dari sidik jari. Konfigurasi jaringan yaitu maksimal <em>epoch</em> = 3000, <em>learning rate</em> = 1, target <em>error</em> = 0.1, <em>hidden layer</em> = 17. Pelatihan jaringan syaraf tiruan pada konfigurasi tersebut menghasilkan nilai <em>error</em> terkecil dari ciri citra sebesar 0.0000085.</p><p class="Abstrak"> </p><p class="Judul2"><strong><em>Abstract</em></strong><em> </em></p><p class="Judul2"><em><br /></em></p><p class="Judul2"><em>The security system that aims as a monitoring system in smart home such as monitoring laboratory users, libraries, or storage rooms and borrowing practical equipment in the study program of a campus, weapons storage room, to a residence, requires reliable securities to facilitate identification of room users or prevention from theft, it is designed a monitoring system through fingerprint image recognition using ZFM60 sensors, artificial neural networks and MySQL. The goal is to get relevant patterns from the image and eliminate irrelevant information or variables. The method used is experimental, consisting of fingerprint data collection, image processing system design, hardware and software manufacturing and testing, and system implementation. The result of the process of recognition or clarification of fingerprint images through the Matlab GUI, the error value of processing and training of fingerprint images with artificial neural networks, is used as a feature of the image and stored as a data base on MySQL, then compared with the error value of the new fingerprint image that is clarified. The recognizable image value is between -0,0005 to 0,0005, beyond this limit is an unrecognized image. The difference (error value) between the characteristics of the image stored in the data base and the clarified image feature produces a small error value of &lt;0.0005, indicating a reliable backpropagation artificial neural network is implemented in fingerprint recognition to train the image pattern of fingerprints. Network configuration is maximum epoch = 3000, learning rate = 1, target error = 0.1, hidden layer = 17. Artificial neural network training in the configuration produces the smallest error value of the image characteristics of 0.0000085.</em></p>


Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 500
Author(s):  
László Keresztes ◽  
Evelin Szögi ◽  
Bálint Varga ◽  
Viktor Farkas ◽  
András Perczel ◽  
...  

The amyloid state of proteins is widely studied with relevance to neurology, biochemistry, and biotechnology. In contrast with nearly amorphous aggregation, the amyloid state has a well-defined structure, consisting of parallel and antiparallel β-sheets in a periodically repeated formation. The understanding of the amyloid state is growing with the development of novel molecular imaging tools, like cryogenic electron microscopy. Sequence-based amyloid predictors were developed, mainly using artificial neural networks (ANNs) as the underlying computational technique. From a good neural-network-based predictor, it is a very difficult task to identify the attributes of the input amino acid sequence, which imply the decision of the network. Here, we present a linear Support Vector Machine (SVM)-based predictor for hexapeptides with correctness higher than 84%, i.e., it is at least as good as the best published ANN-based tools. Unlike artificial neural networks, the decisions of the linear SVMs are much easier to analyze and, from a good predictor, we can infer rich biochemical knowledge. In the Budapest Amyloid Predictor webserver the user needs to input a hexapeptide, and the server outputs a prediction for the input plus the 6 × 19 = 114 distance-1 neighbors of the input hexapeptide.


Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Rahel Jedamski ◽  
Jérémy Epp

Non-destructive determination of workpiece properties after heat treatment is of great interest in the context of quality control in production but also for prevention of damage in subsequent grinding process. Micromagnetic methods offer good possibilities, but must first be calibrated with reference analyses on known states. This work compares the accuracy and reliability of different calibration methods for non-destructive evaluation of carburizing depth and surface hardness of carburized steel. Linear regression analysis is used in comparison with new methods based on artificial neural networks. The comparison shows a slight advantage of neural network method and potential for further optimization of both approaches. The quality of the results can be influenced, among others, by the number of teaching steps for the neural network, whereas more teaching steps does not always lead to an improvement of accuracy for conditions not included in the initial calibration.


Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 47
Author(s):  
Vasyl Teslyuk ◽  
Artem Kazarian ◽  
Natalia Kryvinska ◽  
Ivan Tsmots

In the process of the “smart” house systems work, there is a need to process fuzzy input data. The models based on the artificial neural networks are used to process fuzzy input data from the sensors. However, each artificial neural network has a certain advantage and, with a different accuracy, allows one to process different types of data and generate control signals. To solve this problem, a method of choosing the optimal type of artificial neural network has been proposed. It is based on solving an optimization problem, where the optimization criterion is an error of a certain type of artificial neural network determined to control the corresponding subsystem of a “smart” house. In the process of learning different types of artificial neural networks, the same historical input data are used. The research presents the dependencies between the types of neural networks, the number of inner layers of the artificial neural network, the number of neurons on each inner layer, the error of the settings parameters calculation of the relative expected results.


Author(s):  
M. A. Rafe Biswas ◽  
Melvin D. Robinson

A direct methanol fuel cell can convert chemical energy in the form of a liquid fuel into electrical energy to power devices, while simultaneously operating at low temperatures and producing virtually no greenhouse gases. Since the direct methanol fuel cell performance characteristics are inherently nonlinear and complex, it can be postulated that artificial neural networks represent a marked improvement in performance prediction capabilities. Artificial neural networks have long been used as a tool in predictive modeling. In this work, an artificial neural network is employed to predict the performance of a direct methanol fuel cell under various operating conditions. This work on the experimental analysis of a uniquely designed fuel cell and the computational modeling of a unique algorithm has not been found in prior literature outside of the authors and their affiliations. The fuel cell input variables for the performance analysis consist not only of the methanol concentration, fuel cell temperature, and current density, but also the number of cells and anode flow rate. The addition of the two typically unconventional variables allows for a more distinctive model when compared to prior neural network models. The key performance indicator of our neural network model is the cell voltage, which is an average voltage across the stack and ranges from 0 to 0:8V. Experimental studies were carried out using DMFC stacks custom-fabricated, with a membrane electrode assembly consisting of an additional unique liquid barrier layer to minimize water loss through the cathode side to the atmosphere. To determine the best fit of the model to the experimental cell voltage data, the model is trained using two different second order training algorithms: OWO-Newton and Levenberg-Marquardt (LM). The OWO-Newton algorithm has a topology that is slightly different from the topology of the LM algorithm by the employment of bypass weights. It can be concluded that the application of artificial neural networks can rapidly construct a predictive model of the cell voltage for a wide range of operating conditions with an accuracy of 10−3 to 10−4. The results were comparable with existing literature. The added dimensionality of the number of cells provided insight into scalability where the coefficient of the determination of the results for the two multi-cell stacks using LM algorithm were up to 0:9998. The model was also evaluated with empirical data of a single-cell stack.


2014 ◽  
Vol 38 (6) ◽  
pp. 1681-1693 ◽  
Author(s):  
Braz Calderano Filho ◽  
Helena Polivanov ◽  
César da Silva Chagas ◽  
Waldir de Carvalho Júnior ◽  
Emílio Velloso Barroso ◽  
...  

Soil information is needed for managing the agricultural environment. The aim of this study was to apply artificial neural networks (ANNs) for the prediction of soil classes using orbital remote sensing products, terrain attributes derived from a digital elevation model and local geology information as data sources. This approach to digital soil mapping was evaluated in an area with a high degree of lithologic diversity in the Serra do Mar. The neural network simulator used in this study was JavaNNS and the backpropagation learning algorithm. For soil class prediction, different combinations of the selected discriminant variables were tested: elevation, declivity, aspect, curvature, curvature plan, curvature profile, topographic index, solar radiation, LS topographic factor, local geology information, and clay mineral indices, iron oxides and the normalized difference vegetation index (NDVI) derived from an image of a Landsat-7 Enhanced Thematic Mapper Plus (ETM+) sensor. With the tested sets, best results were obtained when all discriminant variables were associated with geological information (overall accuracy 93.2 - 95.6 %, Kappa index 0.924 - 0.951, for set 13). Excluding the variable profile curvature (set 12), overall accuracy ranged from 93.9 to 95.4 % and the Kappa index from 0.932 to 0.948. The maps based on the neural network classifier were consistent and similar to conventional soil maps drawn for the study area, although with more spatial details. The results show the potential of ANNs for soil class prediction in mountainous areas with lithological diversity.


Sign in / Sign up

Export Citation Format

Share Document