Program Code Research Articles

Hybrid GPU–CPU Efficient Implementation of a Parallel Numerical Algorithm for Solving the Cauchy Problem for a Nonlinear Differential Riccati Equation of Fractional Variable Order

The numerical solution for fractional dynamics problems can create a high computational load, which makes it necessary to implement efficient algorithms for their solution. The main contribution to the computational load of such computations is created by heredity (memory), which is determined by the dependence of the current value of the solution function on previous values in the time interval. In terms of mathematics, the heredity here is described using a fractional differentiation operator in the Gerasimov–Caputo sense of variable order. As an example, we consider the Cauchy problem for the non-linear fractional Riccati equation with non-constant coefficients. An efficient parallel implementation algorithm has been proposed for the known sequential non-local explicit finite-difference numerical solution scheme. This implementation of the algorithm is a hybrid one, since it uses both GPU and CPU computational nodes. The program code of the parallel implementation of the algorithm is described in C and CUDA C languages, and is developed using OpenMP and CUDA hardware, as well as software architectures. This paper presents a study on the computational efficiency of the proposed parallel algorithm based on data from a series of computational experiments that were obtained using a computing server NVIDIA DGX STATION. The average computation time is analyzed in terms of the following: running time, acceleration, efficiency, and the cost of the algorithm. As a result, it is shown on test examples that the hybrid version of the numerical algorithm can give a significant performance increase of 3–5 times in comparison with both the sequential version of the algorithm and OpenMP implementation.

C Source code Obfuscation using Hash Function and Encryption Algorithm

Obfuscation is a technique for transforming program code into a different form that is more difficult to understand. Several obfuscation methods are used to obfuscate source code, including dead code insertion, code transposition, and string encryption. In this research, the development of an obfuscator that can work on C language source code uses the code transposition method, namely randomizing the arrangement of lines of code with a hash function and then using the DES encryption algorithm to hide the parameters of the hash function so that it is increasingly difficult to find the original format. This obfuscator is specifically used to maintain the security of source code in C language from plagiarism and piracy. In order to evaluate this obfuscator, nine respondents who understand the C programming language were asked to deobfuscate the obfuscated source code manually. Then the percentage of correctness and the average time needed to perform the manual deobfuscation are observed. The evaluation results show that the obfuscator effectively maintains security and complicates the source code analysis.

Investigations on the seismic behaviour of concrete-filled thin-walled elliptical steel tubular column: Testing and novel FE modelling

This paper designs and tests a total of eight concrete-filled thin-walled elliptical steel tubular (CFEST) columns imposed with lateral cyclic load and axial force to acknowledge their seismic behaviour. The crucial seismic performance analyses on the failure modes, the seismic strength, the ductility index, the energy dissipation, the strength degeneration, and rigidity degeneration of the thin-walled CFEST columns are successively performed. Then a novel numerical analytical approach based on OpenSees software is developed initially by using a code programming process for the elliptical cross section. Particularly, the featured seismic properties of the CFEST column on the strength, rigidity and energy dissipation with respect to those of circular and square CFST columns are revealed. Development rules of CFEST columns’ seismic behaviour under the influence of various material and geometric parameters are investigated as well. Finally, calculation formulae for assessing the initial rigidity, peak force, peak displacement and descending rigidity of the CFEST column subjected to cyclic load are proposed. The findings indicate that the thin-walled CFEST column offers good seismic performance. Unlike the circular and square CFST columns, the outward local buckling failure of the steel tube is usually developed from the small to the large curvature regions. Under the same sectional area and steel ratio, the seismic resistance, initial rigidity, and energy dissipation of the CFEST column loaded along the major axis are much higher than those of the circular and square CFST columns, which should be fully used in engineering practice.

An Improved Approximation for DIPPR-Based Predicting Speed of Sound in Long-Chained n-Alkanes

IIn this short communication, we revise a correlation for the saturated liquid isothermal compressibility based on the data available in DIPPR (Postnikov, 2016) which considers the molecular non-sphericity and addresses a problem of predicting speeds of sound in saturated long-chained alkanes. In addition, we correct a misprint appeared in the cited work and provide programming code used for the realisation of the proposed calculations.

Virtual reality: a promising instrument to promote sail education.

Sailing has gained an increasing attention among children and adolescents in China, which raised a strong need for sail courses through physical education (PE). However, challenges in teaching practice arise with rapid development of the sport. In the current study, we proposed a perspective that virtual reality (VR) technology makes high-quality sail education accessible for students. Critical analysis summarized the prominent features that enhance sail education, including immersive experience, interactive learning, the first-person view, and practice under well-controlled conditions. Further, research on VR sport training indicated successful transfer from virtual environment to real situation. Specifically, significant improvement in skill performance and tactical behaviors were identified, which was attributed to the enhanced perception-action coupling after VR training. Additionally, VR-based coding programs provide students with affordances of designing the virtual environment. The content design education promotes comprehension and application of knowledge and theories when students develop the simulated environment with a high level of presence. Therefore, VR technology is a promising instrument to meet the increasing demand on sail education. While VR enriches educational resources for a large class size, the interdisciplinary feature of VR-based sail course can attract students with different study interests and backgrounds to the class.

A novel perspective for M-polynomials to compute molecular descriptors of borophene nanosheet

Nanomaterials feature exceptional, one-of-a-kind qualities that might be used in electronics, medicine, and other industries. Two-dimensional nanomaterials called borophene have a variety of intriguing characteristics, which helped them to leave an indelible impression in the fields of chemistry, material science, nanotechnology, and condensed matter physics. The concept of modelling the structure of a molecule or chemical network to a chemical graph and then quantitatively analysing them with the aid of topological descriptors was a major advance in the fields of mathematics and chemistry, with a wide range of applications. M-polynomial approach is a very versatile and quick method for computing the degree-based descriptors of chemical graphs or networks. The degree-based descriptors of the beta _{12}-Borophene nanosheet are established in this study utilising the M-polynomial technique. A program code that enables to generate the M-polynomial of any chemical structure was developed in Java platform and the same is displayed. At the conclusion, the numerical and graphical comparison based on the identified analytic expressions is also provided. Additionally, the QSPR analysis was also carried out and the outcoms are presented therein.

Web Store Teh Krisan (erpekrisan) Rachmat Purnama Farm

The Rachmat Purnama Farm Company, a producer of chrysanthemum flowers located in Cianjur Regency, has made efforts to process chrysanthemum flowers into chrysanthemum tea. However, the marketing remains limited, as sales are conducted directly. Consequently, the company recognizes the need for an online web store to enhance its marketing reach. The purpose of this system is to provide customers with information about chrysanthemum tea and facilitate convenient purchase transactions. The waterfall model is used as the software development method, which covers requirements analysis, system design, program code development, program testing, and program implementation and maintenance. The features of the online web store include account management, customer management, product categorization, product listings, attributes, sales, payments, shipping, and transaction reports. The implementation has positively impacted the company’s sales of chrysanthemum tea products, as shown by the increasing number of online purchases. Moreover, the marketing area coverage has expanded to Jakarta and Kalimantan.

Programmable dual-band acoustic topological insulator with dynamically movable interface states

Topological acoustic interface states in one-dimensional (1D) acoustic topological insulators (ATIs) are zero-dimensional (0D) topological states localized at an interface. Unlike topological edge states that can propagate to deliver information in acoustic waveguides, the 0D topological interface states generally cannot serve as information carriers to deliver information from one location to another due to their intrinsic localization. Here, we design and demonstrate a 1D ATI with a movable interface, enabling the 0D topological acoustic interface states to deliver information from one location to another. The ATI design is based on two types of elemental building blocks—denoted as “1” and “0”—which are programmable. These elements of 1 and 0, when periodically arranged, can form topologically distinct crystals, whose interface hosts acoustic topological interface states in two bandgaps simultaneously. Since these two types of elements can switch from each other with external control, a programmable 1D dual-band ATI can be constructed. By programming coding sequences of 1 and 0 elements, we can observe dynamically movable 0D topological interface states riding on a moving interface along the 1D ATI in both bandgaps. Our work opens an avenue to develop topological acoustic devices with programmable and dynamic functions, which may have a variety of potential applications in the fields of energy trapping, topological pumping, information processing, and sound communication.

Implementation of Fuzzy Logic for Chili Irrigation Integrated with Internet of Things

Chili, mustard greens, and tomatoes have always been farmers' favored crops, despite their high water and labor demands. Adapt to these conditions by utilizing smart agriculture systems (SAS) agricultural techniques that involve technology such as automatic irrigation that regulates watering based solely on routine, regardless of land conditions. This type of control during the transitional season can lead to root rot and fungisarium disease on chile plants. In the form of an embedded system with internet of things (IoT) monitoring, a system incorporating artificial intelligence such as fuzzy logic is proposed as a solution. Fuzzy logic will regulate irrigation based on the land's humidity and temperature using computational mathematics. Beginning with the fuzzyification stage to map the sensor's temperature and humidity input values, fuzzy logic is applied. The creation of an inference engine in the NodeMcu 8266 microcontroller to interpret fuzzy rule statements in the form of aggregation of minimum conditions with the AND operator, followed by the combination of a single set value of 0 and 1 in the fuzzy system to produce an appropriate actuator response After the entire system has been prototyped, testing is conducted to determine the responsiveness of the fuzzy program code to changes in the simulated agricultural cultivation land ecosystem. This study found that the fuzzy logic program code embedded in the nodeMCU8266 microcontroller effectively controls the spraying duration of the pump in response to various simulated environmental conditions within 3.6 seconds.

Comparison of Semi-Empirical Impedance Models for Locally-Reacting Acoustic Liners in a Wide Range of Sound Pressure Levels

A comparison is considered of the experimentally obtained impedance of locally reacting acoustic liner samples with the impedance calculated using semi-empirical Goodrich, Sobolev and Eversman models. The semi-empirical impedance models are outlined. In the experiment, the impedance is synchronously measured on a normal incidence impedance tube by the transfer function method and Dean’s method. A modification of the conventional normal incidence impedance tube is proposed to obtain these measurements. To automate the measurements, a program code is developed that controls sound generation and the recording of signals. The code includes an optimization procedure for selecting the voltage on an acoustic driver, providing the required sound pressure level on the face of the sample at different frequencies. The geometry of acoustic liner samples and specifics of synchronous impedance measurements by the aforementioned methods are considered. Experiments are performed at sound pressure levels from 100 to 150 dB in the frequency range of 500–3500 Hz. A comparative analysis of semi-empirical models with the experimental results at different sound pressure levels is carried out.

Enhancing heat transfer with 50%–50% water‐ethylene glycol hybrid nanofluid flow over a nonlinear stretching sheet

AbstractIn this article thermophysical properties of nanoparticles with water‐ethylene glycol mixture and its impact in augmenting of heat transport is presented. Boundary layer flow over a stretching surface with simultaneous effects of viscous dissipation, radiation, electric and magnetic field are taken into account. Self‐similarity transformation is utilized to modify the flow governing equations into system of differential equations and solved by shooting method. Program code is validated with existing results in literature and results shows good agreement. Influence of various physical parameters are visualized and Nusselt number, skin friction quantities are computed. We have observed that application of electric field increases Nusselt number. Eckert number decreases the Nusselt number for both nanofluid and hybrid nanofluid.

Development of models of current relays and power direction relays in the MATLAB software

During pandemics and military aggressions, the continuation of education is ensured by the active implementation of distance learning technologies. A significant number of real-life processes can be described using mathematical models. Their further implementation in the program code and the finished software product allows them to be effectively used in virtual studies of relay protection schemes. For the correct functionality of any virtual relay or protection complex, it is necessary to build a model that takes into account the real characteristics of its constituent elements. In case of absence of the latter, they should be determined empirically. To create a virtual laboratory work on the study of the RT-40 current relay, based on the parameters specified in the passport for this device, an algorithm was created that allows the user to interactively determine the main characteristics of the relay: tripping current, release current, and response time depending on the current through the relay using various circuit elements (sliders, regulators, etc.). The algorithm of the program “Research of characteristics of power direction relay RBM-171” uses the angular characteristics and sensitivity characteristics of the real relay RBM-171, which were converted into digital form. For the RBM-178 relay, which has a different connection scheme and maximum sensitivity angle from the previous test stand, a separate test stand “Study of the RBM-178 power direction relay” was created. The logic of its operation is based on the detection of zero-sequence currents and voltages using the method of symmetrical components. All laboratory circuits have visualization and indication of the states of the circuit elements present on the stands. This allows the user to achieve more accurate results and get closer to testing relays in real laboratory conditions.

Anisotropic programmable metasurface beam splitter based on diode real-time control

we propose an anisotropic programmable coding metasurface, which is composed of digital coding elements integrated with PIN diode. The "0″ and "1″ states of the diode are controlled in real time by external voltages, and a single metasurface unit is controlled by the FPGA (Field Programmable Gate Array). Due to the polarization-sensitive characteristics, it is not only possible to switch the polarization states in the orthogonal two directions separately, but also to realize the remote scattering control at any angle by means of convolution coding. The metasurface can be converted on polarization (linear polarization or circular polarization) by means of real-time coded modulation. We further experimentally prepared a diode based programmable coding metasurface and measured the angle of far-field scattering using a microwave test system. The independent polarization wavefront control greatly enhances the channel capacity of metasurface, and programmable metasurface has a higher degree of freedom when multifunction modulation is realized.

Robust Malware identification via deep temporal convolutional network with symmetric cross entropy learning

AbstractRecent developments in the field of Internet of things (IoT) have aroused growing attention to the security of smart devices. Specifically, there is an increasing number of malicious software (Malware) on IoT systems. Nowadays, researchers have made many efforts concerning supervised machine learning methods to identify malicious attacks. High‐quality labels are of great importance for supervised machine learning, but noises widely exist due to the non‐deterministic production environment. Therefore, learning from noisy labels is significant for machine learning‐enabled Malware identification. In this study, motivated by the symmetric cross entropy with satisfactory noise robustness, the authors propose a robust Malware identification method using temporal convolutional network (TCN). Moreover, word embedding techniques are generally utilised to understand the contextual relationship between the input operation code (opcode) and application programming interface function names. Here, considering the numerous unlabelled samples in real‐world intelligent environments, the authors pre‐train the TCN model on an unlabelled set using a word embedding method, that is, Word2Vec. In the experiments, the proposed method is compared with several traditional statistical methods and more recent neural networks on a synthetic Malware dataset and a real‐world dataset. The performance comparisons demonstrate the better performance and noise robustness of their proposed method, especially that the proposed method can yield the best identification accuracy of 98.75% in real‐world scenarios.

Machine learning guided optimal composition selection of niobium alloys for high temperature applications

Nickel- and cobalt-based superalloys are commonly used as turbine materials for high-temperature applications. However, their maximum operating temperature is limited to about 1100 °C. Therefore, to improve turbine efficiency, current research is focused on designing materials that can withstand higher temperatures. Niobium-based alloys can be considered as promising candidates because of their exceptional properties at elevated temperatures. The conventional approach to alloy design relies on phase diagrams and structure–property data of limited alloys and extrapolates this information into unexplored compositional space. In this work, we harness machine learning and provide an efficient design strategy for finding promising niobium-based alloy compositions with high yield and ultimate tensile strength. Unlike standard composition-based features, we use domain knowledge-based custom features and achieve higher prediction accuracy. We apply Bayesian optimization to screen out novel Nb-based quaternary and quinary alloy compositions and find these compositions have superior predicted strength over a range of temperatures. We develop a detailed design flow and include Python programming code, which could be helpful for accelerating alloy design in a limited alloy data regime.

A numerical approach to sequential multi-hypothesis testing for Bernoulli model

In this article, we deal with the problem of sequential testing of multiple hypotheses. The main goal is minimizing the expected sample size (ESS) under restrictions on the error probabilities. We take, as a criterion of minimization, a weighted sum of the ESSs evaluated at some points of interest in the parameter space, aiming at its minimization under restrictions on the error probabilities. We use a variant of the method of Lagrange multipliers based on the minimization of an auxiliary objective function (called Lagrangian) combining the objective function with the restrictions, taken with some constants called multipliers. Subsequently, the multipliers are used to make the solution comply with the restrictions. We develop a computer-oriented method of minimization of the Lagrangian function that provides, depending on the specific choice of the parameter points, optimal tests in different concrete settings, as in Bayesian, Kiefer-Weiss, and other settings. To exemplify the proposed methods for the particular case of sampling from a Bernoulli population, we develop a set of computer algorithms for designing sequential tests that minimize the Lagrangian function and for the numerical evaluation of test characteristics like the error probabilities and the ESS. We implement the algorithms in the R programming language. The program code is available in a public GitHub repository. For the Bernoulli model, we made a series of computer evaluations related to the optimality of sequential multi-hypothesis tests, in a particular case of three hypotheses. A numerical comparison with the matrix sequential probability ratio test is carried out. A method of solution of the multi-hypothesis Kiefer-Weiss problem is proposed and is applied for a particular case of three hypotheses in the Bernoulli model.

Analysis of Diffusion Coefficients of Iron Monoboride and Diiron Boride Coating Formed on the Surface of AISI 420 Steel by Two Different Models: Experiments and Modelling.

In the present work, two mathematical diffusion models have been used to estimate the growth of the iron monoboride and diiron boride coating formed on AISI 420 steel. The boronizing of the steel was carried out with the solid diffusion packing method at a boronizing temperature of 1123 K-1273 K. Experimental results show the two-coating system consists of an outer monoboride and an inner diiron boride coating with a predominantly planar structure at the propagation front. The depth of the boride coating increases according to temperature and treatment time. A parabolic curve characterizes the propagation of the boride coatings. The two proposed mathematical models of mass transfer diffusion are founded on the solution corresponding to Fick's second fundamental law. The first is based on a linear boron concentration-penetration profile without time dependence, and the second model with time dependence (exact solution). For both models, the theoretical law of parabolic propagation and the average flux of boron atoms (Fick's first fundamental law) at the growth interfaces (monoboride/diiron boride and diiron boride/substrate) are considered to estimate the propagation of the boride coatings (monoboride and diiron boride). To validate the mathematical models, a programming code is written in the MATLAB program (adaptation 7.5) designed to simulate the growth of the boride coatings (monoboride and diiron boride). The following parameters are used as input data for this computer code: (the layer thicknesses of the FeB and Fe2B phases, the operating temperature, the boronizing time, initial formation time of the boride coating, the surface boron concentration limits, FeB/Fe2B and Fe2B/Fe growth interfaces, and the mass transfer diffusion coefficient of boron in the iron monoboride and diiron boride phases). The outputs of the computer code are the constants εFeB and εFe2B. The assessment of activation energies of AISI 420 steel for the two mathematical models of mass transfer is coincident (QFeB=221.9 kJ∙mol-1 and QFe2B=209.1 kJ∙mol-1). A numerical analysis was performed using a standard Taylor series for clarification of the proximity between the two models. SEM micrographs exhibited a strong propensity toward a flat-fronted composition at expansion interfaces of the iron monoboride and diiron boride coating, confirmed by XRD analysis. Tribological characterizations included the Vickers hardness test method, pin-on-disc, and Daimler-Benz Rockwell-C indentation adhesion tests. After thorough analysis, the energies were compared to the existing literature to validate our experiment. We found that our models and experimental results agreed. The diffusion models we utilized were crucial in gaining a deeper understanding of the boronizing behavior of AISI 420 steel, and they also allowed us to predict the thicknesses of the iron monoboride and diiron boride coating. These models provide helpful approaches for predicting the behavior of these steels.

The system for automated assessment of knowledge and practical skills in programming

The article describes a software package (automated knowledge assessment system) that allows in practice to apply a new type of tasks for automated control of knowledge and skills in programming, based on a constructive-selective method. In such tasks, the student constructs an answer (program) from the proposed components (lines of program code), and the task involves many correct answers. A new type of task allows assessing the knowledge of previously studied algorithms and skills of writing programs, that complement black-box testing. The developed automated control system consists of two subsystems: “Processing” and “Demonstration”. The “Demonstration” subsystem, which is a web application, provides the minimum necessary set of features for using this type of tasks in the educational process, and it also serves as an example that can be used when developing extensions for other systems. The “Processing” subsystem allows integration of a new type of programming tasks into various automated knowledge assessment systems and LMS, if they provide an opportunity for expansion. A teacher creates manually or using the tools developed by the authors of this article a pattern and a list of components before applying a new type of task. A student makes up the answer (program) from the proposed components (lines of program code). The assessment algorithm evaluates the compliance of the student’s answer with the pattern and assesses compliance in the interval [0; 1].

APPLICATION OF DISCONTINUOUS SOLUTIONS IN BOUNDARY ELEMENT METHOD FOR THE BENDING PROBLEMS OF KIRCHHOFF PLATES WITH AN ARBITRARY CONTOUR

The discontinuous solutions represent a new direction for the indirect Boundary Element Method (BEM) in the indirect formulation. Discontinuous solutions represent those functions, which when crossing certain lines, the transverse deflection, the slope angle, the bending moment and the generalized shear force may have jumps. These can be used to solve important problems for which the existing methods do not have solutions or a satisfactory accuracy, such as: plates of arbitrary contour, presence of defects, mixed boundary conditions, contact problems, infinite domains etc. In this paper, we describe the methodology of application and the numerical implementation of discontinuous solutions for the bending problems of plates with an arbitrary contour in the classical theory (Kirchhoff). For this purpose, programming codes were developed in the Matlab language, which allowed to calculate the displacements and efforts in the plate. The obtained results were compared with the Finite Element Method (FEM) for different mesh densities.

Проектирование и реализация административного узла институциональной обучающей виртуальной среды языкового вуза

The research is aimed at developing and testing a node of the institutional virtual learning environment of a linguistic university to monitor the learning process and to assist the management of the educational programs in decision-making, which would be organically combined with the corresponding lear¬ning nodes – both technically and conceptually. Scientific novelty lies in the fact that the notion of an ad-ministrative node is introduced into the concept of the virtual learning environment for the first time; in addition, the paper proposes an approach to the development of software solutions that are secondary to methodological aspects, that is, they proceed from the needs of the learning process and not from any “technical” circumstances. In the course of the research, firstly, the requirements for the functions of the administrative node were drawn up and the technical tools for its implementation were listed, sec-ondly, its complete programming code was written, including the construction of an interactive graphical user interface, and, thirdly, the created software package was tested and its viability as a node of the insti-tutional virtual learning environment of a language university was established. As a result, the correctness of the approach to creating software for the needs of the learning process as an add-on to the basis, which is made up of methodological components, has been proved. This approach is opposed to choosing ready-made software solutions, which lack flexibility and are poorly compatible with the actual processes of or-ganizing and implementing educational programs in specific conditions.