bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Game of Pursuit Time Satisfy the Geometric Constraints in l
2 Space
Authors: Waziri Usman , Ibragimov Gafurjan , Usman Abdullahi , Babura Babangida Ibrahim , Adebayo Salaudeed A. 
Published: April 2021

Abstract
In the present article, we present a differential game of pursuit problem with the case of geometric constraint in the Hilbert space l
2. The game is given by system of 2-infinite systems of first order ordinary differential equations (ODEs). Geometric constraint are imposed on the control functions of players. The game is began from a given point z
0 called the initial position. It is given another point z
1 in the space l
2. The Pursuer targeting to bring the state of the system from z
0 to z
1 where an equation to find a guaranteed pursuit time is obtained while that of the Evader action is opposite. The game is assumed to be completed if z(t) = z
1 at some time t. Moreover, a control problem is studied and then extended to the differential game of pursuit where the strategy for the Pursuer is constructed explicitly.
Deriving the Community Readiness Index in Facing the Industrial Revolution 4.0 in Indonesia
Authors: Nurmawiya  , Kurniawan R 
Published: April 2021

Abstract
The demographic dividend that is being experienced by Indonesia is an opportunity to increase the economic growth rate. At the same time, Indonesia has enrolled in the revolution era of industry 4.0, which can provide benefits and boost the Indonesian economy. However, this can negatively impact if the community is not ready, such as increased unemployment due to disruption and job automation. This study examines how ready the Indonesian people are to face the industry 4.0 related to education and the use of information and communication technology (ICT) by forming an index utilizing the factor analysis and then grouping districts based on the index formed. The data used comes from the National Socio-Economic Survey (SUSENAS) 2018 by the Statistics Indonesia (BPS). The results show that there are differences in community readiness based on the groupings formed. This research also shows that in general, Papua and East Nusa Tenggara are not ready to face this era. Therefore, policies are necessitated following each region’s conditions to improve education and ICT, especially Papua and East Nusa Tenggara, which require more attention.
Development of Automated Flight Data Collection System for Air Transportation Statistics
Authors: Panuntun Satria Bagus , Pramana Setia 
Published: April 2021

Abstract
Data and information regarding air transportation is very crucial for all aspects, such as economy, people mobility and tourism. Currently, the Air Transportation Statistics is based on administrative data of different institutions. it is necessary to have a new data source regarding air transportation activities that can be used as an alternative reference for air transportation data which is faster and more granular. This research aims to study a new approach to produce air transportation statistics, especially air transportation statistics in Indonesia from big data that can be used as comparative or as complementary data for official air transportation statistics. This research using a website scraping method from a site that provides monitoring and tracking services for all flights in the world. The flight data was collected daily from the 15 busiest airports in Indonesia for both departure and arrival flights using the API provided by the website. The Scrapy module in the Python programming language is implemented. The data was collected daily from March 15, 2020, to August 31, 2020. The results of the flight data set contain information about the flight code, aircraft code, airline name, departure airport, departure city, arrival airport, arrival city, date/time of departure and arrival, and flight status. The result shows that it is feasible to use big data as a comparative or as a complementary of official statistics, especially in air transportation statistics. By using the web scraping technique, the indicator that usually requires more time and cost can be done in real-time and less cost. This new approach is expected to improve the quality of official air transportation statistics.
Clusterwise Regression Model for Statistical Downscaling to predict Daily Rainfall using Gamma Distribution
Authors: Muthia Nadhira F , Soleh Agus M , Djuraidah Anik 
Published: April 2021

AbstractThis study presents the development of clusterwise regression with gamma distribution and normal distribution. This clusterwise regression model is expected to be a solution for high variance data in order to minimize the error rate in modeling. The first study is simulation of clusterwise regression with gamma distribution and normal-gamma mixture. This simulation is divided into two-cluster and three-cluster simulations with gamma distribution, normal distribution, and mixed normal-gamma distribution with different parameters. The application of clusterwise regression was carried out at four rain stations in West Java, including Bandung, Bogor, Citeko, and Jatiwangi rain stations by first doing variable reduction using principal component analysis.
Analysis of Credit Bank Distribution with Seemingly Unrelated Regression Method on Panel Data
Authors: Jannah W , Sulvianti I D , Indahwati  , Silvianti P , Kurnia A 
Published: April 2021

Abstract
One of the bank’s business activities that most impactful for economic growth is credit distribution that is affected by independent variables including Thirds Party Funds, bank’s performance (CAR and LDR), credit interest rates, NPL, and external variables such as BI Certificate, BI Rate, and exchange rates. Panel data regression is used to analyze the impact of those variables. The type of this research data is combined features of both cross-section and time-series obtained from SPI. The study is aimed to see variables that affect credit distributions at the commercial banks between January 2016 until December 2019. Among the common error structures, there are individual correlations known as contemporaneous correlations. This case can be resolved by seemingly unrelated regression analysis. The result showed that Third Party Funds and LDR have significantly impacted the credit distribution of all types of commercial banks with a goodness of fit measure is 99.909%. Moreover, all variables studied were impact the credit distribution of the Joint Venture Bank and the Regional Development Bank.
Analysis of Residential Property Price Index (RPPI) Using Multi Input Transfer Function
Authors: Chirsty Y , Novita M , Soemartojo S M 
Published: April 2021

Abstract
Residential property or home is one of the basic human needs as a shelter, to be able to continue to live. As the population in Indonesia increases, express the need for residential property will also increase. The movement of residential property prices in Indonesia can be observed from the Residential Property Price Index (RPPI) issued by Bank Indonesia. Residential property prices can be influenced by several factors. For example in economic, the movement of RPPI can be influenced by several factors such as inflation, Composite Stock Price Index (RPPI) and loan interest rates. Forecasting the RPPI can be done with times series modeling. Modeling RPPI using three influencing variables requires a multivariate time series model. The multi-input transfer function model is a multivariate model that can be used in modeling RPPI. In the multi-input transfer function model there is an output series (y

t
) which is the RPPI which is estimated to be influenced by several input series (x

jt
), which are inflation, IHSG and loan interest rates. Based on the model obtained in this study, it can be seen that the prediction of RPPI at the t-time is influenced by the amount of inflation in the previous two months until previous five months, influence by loan interest rates without delay so that it is influenced by the t-time until previous three months, influenced by the IHSG at t-time until previous four months, and also influenced by itself at one month before to four months before.
Performance of SMOTE in a random forest and naive Bayes classifier for imbalanced Hepatitis-B vaccination status
Authors: Putri V M , Masjkur M , Suhaeni C 
Published: April 2021

Abstract
The alternative approach to predict the classification of HB vaccination status is using a machine learning approach such as random forest and naive Bayes classifier. However, for imbalanced classification, the algorithms are biased towards the majority class. To increase the accurate prediction of the classifier, we consider the Synthetic Minority Oversampling Technique (SMOTE) to have more balanced data. The purpose of this study was to compare the performance of SMOTE in the random forest and naive Bayes classifier for imbalanced Hepatitis-B vaccination data. The study used the National Socio-Economic Survey data in 2017 for Aceh province with 2264 cases and 14 variables. The results show that the application of SMOTE in the random forest and naive Bayes classifier improves the accuracy of identification of Hepatitis-B non-vaccination status by 30.08% and 26.09%, respectively, compared to non-SMOTE. Random forest with SMOTE is the best model for classification HB vaccination status. The most important factors that influence the Hepatitis-B vaccination status of Aceh province are the mother’s last education, mother’s occupation, father’s occupation, father’s previous education, and the number of health facilities.
Preparing a Big Data Utilization Communication Strategy
Authors: Faris M , Pramana S 
Published: April 2021

Abstract
Covid-19 pandemic has brought lot of changes to the world, including data production. In this pandemic situation, conducting surveys and censuses in conventional way becomes too risky. However, the community’s need for data is even greater as the public indeed has a great interest in monitoring the development of the social and economic conditions affected by Covid-19. Big Data becomes an alternative data source in meeting this need because it can provide a variety of data that we can process into very useful information quickly. The big data utilization for all fields as well as to inform the policy-making becomes very important nowadays. However, to make clear understanding and well public acceptance on the output of big data utilization needs effective communication strategy. There are five concepts to deliver excellent communication on statistics particularly to promote big data, namely extracting and describing insights from the pool of available statistics, market segmentation, forms of communication, channels of communication, and statistical description. This article proposes effective communication strategy to increase public acceptance and awareness on big data through different communication channels by targeting different characteristics of audiences.
Mach number effect on droplet phase angular distribution behind a nozzle under near-wall liquid film outflow with co-current gas flow into vacuum
Authors: Vyazov Y N , Prikhodko V G , Yarygin I V 
Published: April 2021

Abstract
The paper is devoted to experimental study of near-wall ethanol film outflow with high-velocity co-current air flow from sonic and supersonic nozzles into vacuum. Using the developed measurement techniques (droplet phase flow structure visualization, deposition of droplets on paper substrates, spectrophotometry method), the effect of the nozzle Mach number on angular distribution of droplet phase in the central and the peripheral flow regions behind the nozzle exit is established.
Thermal effect on the film of a solution with a volatile component
Authors: Borodina K A , Tatosov A V 
Published: April 2021

Abstract
Interfacial convection is a widespread phenomenon occurring in various fields of technology, including chemical technology. Marangoni convection is of greatest interest in the case of thin liquid films. Phase transitions significantly affect the convective flow by changing the surface tension coefficient. In this work, we study the behavior of a thin film of a binary homogeneous solution when it is heated. A change in the temperature of the free surface together with the escape of the volatile component leads to two opposite effects in the direction of the surface tension gradient. The necessity of taking into account the motion of the volatile component over the solution surface is substantiated, analytical estimates and solutions are obtained.
Comparison of emission concentrations during the combustion of a double hydrate propane-methane at different temperatures in a muffle furnace
Authors: Morozov V S 
Published: April 2021

Abstract
In recent years, more and more attention in the world has been paid to the development of environmentally friendly technology for combustion gas hydrates. In this work, experimental studies of the combustion of a propane-methane double gas hydrate at different temperatures in a muffle furnace of 650 °C and 950 °C were performed. The increase in temperature in the muffle furnace allowed to reduce harmful emissions and reduce fuel loss. With increasing temperature, the CO concentration decreases by 2.2-2.5 times, CO2 from 7-8% to 3-4% and NOX changes by 1.2–1.5 times, which is associated with an increase in the reaction rate. Emissions of NOX gases during combustion of coal-water suspensions are many times higher than the obtained values of NOX concentrations of methane-propane gas hydrates.
Numerical study of the processes of co-combustion of pulverized coal and gas fuel based on nonstationary methods of turbulence modeling
Authors: Kuznetsov V , Dekterev A , Minakov A 
Published: April 2021

Abstract
In this work, a numerical study of the combustion of pulverized coal in a gas flame is carried out on the basis of the proposed mathematical model of combustion processes, using a nonstationary method for modeling turbulence, complex heat transfer and a reduced mechanism for chemical kinetics. The calculation results show acceptable agreement with the experimental data on the main characteristics of the flame, make it possible to qualitatively correctly determine the structure of the dust and gas flow and derive such parameters as the gas composition, the temperature of particles and gas, the degree of carbon burnout, etc.
Simulation of liquid-steam critical flow from a pipe filled with granular layer
Authors: Khramtsov D P , Nekrasov D A , Moshin A A 
Published: April 2021

Abstract
Based on the method of smoothed particles hydrodynamics a computational model of the critical flow of a vapor-liquid mixture from a pipe with a granular backfill has been developed. The dependence of critical mass flow rate from linear dimensions of the work area, the diameter of the grain filling and pipe length was determined. Numerical results were compared with available experimental data and numerical calculation demonstrates consistency with experimental data. Numerical data on the intensity of vaporization by the cross section of a pipe filled with granular backfill at initial values of the mass fraction of steam from 0.05 to 0.2 were obtained. The non-linearity of the vaporization rate during the mixture moving along the pipe with a decrease in intensity when moving along the length of the pipe is shown.
Features of flow and heat transfer near a pair of circular cylinders
Authors: Seroshtanov V V , Vlasov A S , Suchok V V , Zhidkov N A 
Published: April 2021

Abstract
Synchronous flow and heat transfer study of in a single-phase medium is one of the important engineering and thermophysical problems. To solve this problem, the simultaneous use of PIV and gradient heatmetry is proposed. The investigated model is a pair of heated circular cylinders. Constant cylinders’ surface temperature is ensured by heating with saturated steam. The studies were carried out at various Reynolds numbers and inert-tube distance S, ranging from 0.5d to 4d. The use of gradient heatmetry made it possible to estimate the heat flux pulsations at the second cylinder and then, to compare them with the instantaneous velocity fields obtained using the PIV. The distributions of the heat flux and heat transfer coefficient over the cylinder surface were obtained for the range of Reynolds numbers from 4,8 to 48 × 103. The results are consistent with the data of other authors and show the prospects for the proposed methodology. Moreover, the results on the heat transfer augmentation the same models and in the same modes are presented.
Heat transfer enhancement when boiling on finned surfaces
Authors: Vladimirov V Yu , Chinnov E A 
Published: April 2021

Abstract
In this work, we studied the effect of radial surface finning and hydrophobic fluoropolymer coating of finned surfaces on the intensity of heat transfer at boiling. Two samples were used: 16 fins and 32 fins. At first, experiments were carried out without a hydrophobic coating. After that, the samples were covered with a layer of fluoropolymer and a series of experiments were carried out. During these experiments, the state of the fluoropolymer coating was analyzed. Experiments on a sample with 16 fins showed that deposition of fluoropolymer leads to significant intensification of heat transfer. For the sample with 32 fins, the opposite effect was observed: hydrophobization negatively affected the efficiency of heat transfer. Maximal enhancement of heat transfer, in comparison with finely finned and smooth surfaces, was achieved on a surface with large fins coated with fluoropolymer.
Computational study of enhanced oil recovery from a porous medium using nanosuspension
Authors: Guzei D V , Ivanova S V , Platonov D V , Pryazhnikov A I 
Published: April 2021

Abstract
The paper presents the results of direct numerical simulations of the process of oil displacement by nanosuspension with SiO2 particles from two-dimensional micromodels of a porous medium with different values of permeability. In the calculations, the experimentally measured values of the interfacial tension coefficient and the contact angle of wetting were used. The calculations were performed for pure water and a suspension of silicon oxide nanoparticles with a mass concentration of 1%. The computational study was performed using the VOF method. The influence of the displacement fluid flow rate, nanoparticle concentration and core permeability on the efficiency of oil displacement by nanosuspension was studied. As a result of the work, it was shown that the use of nanosuspensions makes it possible to increase the oil recovery factor. It is shown that with an increase in the mass concentration of particles, the value of the oil recovery factor increases.
Simulation of cuttings removal processes in the horizontal well
Authors: Zhigarev V A , Pryazhnikov M I , Matveev A V , Guzei D V , Shebelev A V 
Published: April 2021

Abstract
The paper presents the results of a numerical simulation of the process of cleaning the annulus of a horizontal well. The effect of the cuttings particle size on the efficiency of cuttings removal from the annulus of the well was studied. The geometry of a real well was used as the calculation model. Cutting particles with sizes from 2 to 5 mm were considered in the numerical study. Velocity profiles of the solid phase (cuttings particles) in annular channels were obtained in the course of conducted numerical simulation.
Heat transfer at a single drop impingement on liquid–vapor–solid triple contact line
Authors: Gigola T G , Cheverda V V , Karchevsky A L , Kabov O A 
Published: April 2021

Abstract
In the current study an experimental investigation of heat transfer at a single drop impingement on liquid-vapor-solid contact line of a liquid layer located on a heated substrate has been performed. The heated thin foil technique is used for experimentation. The interaction dynamics of a drop with a contact line is considered with the help of high-speed visualization and infrared thermography. The obtained experimental data will be processed by solving inversed Cauchy problem for the non-stationary heat transfer equation. The effects of the drop impingement height on the heat flux in the region of the contact line will be determined in the further steps of research.
Minimum and maximum size of levitating water droplets above the surface of a heated liquid layer
Authors: Zaitsev D V , Shatekova A I , Pukhovoy M V 
Published: April 2021

Abstract
This work is devoted to the phenomenon of levitation of liquid microdroplets above hot liquid interfaces. The droplets levitate due to air-vapour upward flow from the liquid surface and grow in time due to condensation. It was found that the diameter of droplets linearly increases with time. The maximum possible and minimum possible droplet sizes were measured depending on the substrate temperature.
Experimental study of the effect of electric discharge on carbon fiber
Authors: Zakirov J U , Kayumov R R , Khazeev K I 
Published: April 2021

Abstract
The results of experimental studies of the effect of an electric discharge on carbon fiber in the discharge voltage range U = 0.2 - 1300 V and at a current I = 0.03 - 1.8 A, at atmospheric pressure are presented. Some features of the combustion of an electric discharge with liquid electrodes are revealed. Some features of the effect of an electric discharge on carbon fiber have been established.
Comparison of initial pressure distributions in shock wave simulation of optical breakdown on surface
Authors: Sattarov A G , Sochnev A V , Ziganshin B R 
Published: April 2021

Abstract
In this work we investigated the velocity of propagation of a shock wave after optical breakdown on the surface, depending on various initial pressure distributions which are simulated in Ansys Fluent. When setting of the shock wave energy of the order of 10 … 20% of the laser pulse energy, results are in satisfactory agreement with experiments. An analysis of the experimental data showed an effect when the velocities of shock waves propagation are comparable but energies of laser pulses differ by two orders of magnitude between each other, which leads to significant deviations from the theory of a point explosion.
Numerical study of the effect of gravitational sedimentation of large particles on the propagation of a shock wave from a homogeneous gas into a polydisperse gas suspension
Authors: Tukmakov D A , Tukmakova N A 
Published: April 2021

Abstract
The effect of the nonuniform concentration of one of the fractions of a two-fraction gas-suspension on the parameters of a shock wave moving from pure gas to a gas-suspension is numerically studied. The motion of a direct shock wave in a two-fraction gas suspension was simulated. The finely dispersed fraction of the gas-suspension had a uniform initial mass content, while larger particles had a nonuniform initial mass content along the y coordinate. It was revealed that in the case of a uniform concentration of all fractions, the shock wave in the channel propagates at a lower speed. It was also found that a nonuniform concentration of the larger particles fraction along the y coordinate affects the spatial distribution of the gas velocity.
Features of a gas discharge with a liquid electrolyte cathode in an extended discharge gap
Authors: Tazmeev K K , Tazmeev A K 
Published: April 2021

AbstractA gas discharge in an extended gap between a liquid electrolyte cathode and a copper anode was studied experimentally. The discharge was obtained in an open air atmosphere at a distance of 2-18 cm between the electrodes. It was revealed that there are combustion modes with a homogeneous and inhomogeneous plasma column. The electrical properties of the discharge in these two combustion modes were studied. The electric field strength in the plasma column was determined by varying the length of the discharge gap.