bluuebunny/crossref_metadata_2025 huggingface dataset:
To the Evaluation of the Insulation State Based on the Analysis of Partial Discharges
Authors: Tetiora S Yu , Silin N V , Petrunko N N
Published: November 2021

The existing partial discharge models, their diagnostic value, and application area are analyzed in the article. The models are considered from the point of view of their improvement or the possibility of creating new diagnostic methods for electrical equipment based on the characteristics of partial discharges. As an example of the implementation of a new approach to partial discharge modeling, a quasi-deterministic model is considered, which makes it possible to obtain information on the real number of cavities in the insulation of high-voltage equipment.
Experimental Marine Studies of Liquid Respiration Technology for Diving/Surfacing of Biological Objects in Capsule to Depth of up to 1500 Meters
Authors: Polivtsev V P , Polivtsev V V , Osipov K N
Published: November 2021

The article considers the study of the liquid respiration technology for diving/surfacing of biological objects in the Black Sea to the depth of 500, 1,000, and 1,500 meters. The authors focus on safe diving/surfacing modes and depths. The authors developed and tried an autonomous capsule attached to a winch with a cable that can be used for the diving and surfacing of the immersed bioobject. The authors provide the key diving/surfacing speeds, as well as maximum diving depths for a dog under spontaneous breathing. The authors present the results of medical research of the bioobject before, during, and after diving involving electrocardiogram, electroencephalogram, as well ultrasound, x-ray, and instrumental tests.
The Principle of Construction of Capacitive Reactive Power Compensators with Three-Stage Regulation
Authors: Klimash V S , Tabarov B D , Antonov E G
Published: November 2021

It is proposed to reduce the number of electrical and electronic devices by 1.5 times in three-stage capacitor installations by changing the connections in the power circuit and using a special control method. The new principle of construction of reactive power compensators will allow, with minimal changes and additions to existing installations, to reduce the costs of their production and the cost of finished products. The existing installations contain three blocks of the same type of capacitors, each of which is equipped with an electrical and electronic device and resistors for their discharge. It is proposed to connect two of these three blocks in parallel without changing the design of the products, using a common electronic device for connecting and disconnecting the resulting block of capacitors with double capacity and a common electrical device in the capacitor discharge circuit of this block. A model is presented in the Matlab environment for the study of dynamic and stationary processes of three-stage reactive power regulation in a new scheme of a capacitor plant. Numerical experiments have shown that when the installation is switched on and off, as well as when switching from one stage of reactive power regulation to another, the proposed device does not create bursts of starting currents. After starting, it almost immediately enters the steady-state operation mode and when switching stages, it also immediately passes from one level of the steady-state values of such to another level of their steady-state values. The installation is switched off without switching losses and without arcing on the mechanical contacts, since thyristor switches with natural switching are switched off first, and then the de-energized mains switch.
Method of Switching on and Off a Power Transformer with a Capacitor Bank in an Electrothermal Installation
Authors: Klimash V S , Tabarov B D
Published: November 2021

The article is devoted to issues related to increasing the energy efficiency of industrial electrothermal installations, both in starting and stationary operating modes due to the use of capacitors and thyristor starters with special control. The results of a significant reduction in the duration of the transient process, elimination of surges and asymmetry of starting currents and voltage drawdowns are presented. The results of full compensation of the reactive power of the network in the steady-state mode are also presented. It is shown that the starting currents do not exceed their steady-state values and that the shutdown of the electrothermal installation is performed without the occurrence of an arc and switching losses at the contacts of the switches. Researches of an electrothermal installation with a capacity of 750 kV⋅A and a voltage of 380 / 80 V are made on the model in the Matlab environment.
A method for Improving the Accuracy of Reactive Power Regulation by a Capacitor Plant
Authors: Klimash S V , Tabarov B D , Klimash V S , Konstantinov A M
Published: November 2021

The problem of low accuracy of reactive power regulation by the most common three-component condenser installations in the industry and its impact on the quality of electricity and the efficiency of its consumption and use in industrial power supply systems is considered. To increase the accuracy of reactive power regulation by at least 2.3 times without changing the circuit of the capacitor plant and the number of switching equipment, a new control algorithm is proposed and described in detail. The results of testing a method for regulating reactive power in the Matlab environment based on the proposed algorithm for controlling capacitor blocks with changed parameters are presented. Numerical experiments have shown the possibility of seven-stage regulation, versus three-stage control in known industrial installations. The capacitor unit is switched on by a mains switch and then by thyristor switches without a surge of currents in the capacitors and without an asymmetry of currents in the network. The installation is switched off in the reverse sequence, first by thyristor switches with natural switching, and then by a mains switch without arcing on its contacts.
Analysis of Filtration Process Influence on the Results of Thermal Imaging Control of the Subsurface Defect’s Geometry in Solving Control Problems of Collaborative Robotic Systems
Authors: Bushuev S V , Romash E V , Bashevskaya O S
Published: November 2021

The paper proposes and experimentally verifies an approach for estimating the thermal imaging error depending from the method of the subsurface defect’s linear dimensions filtering for forming the appropriate commands of the control program in a collaborative robotic system. The results are presented for the absolute error estimation depending on the filtration method with a confidence probability p=0,9972.
The Method of Selecting Protection Devices in the Automated Design of an Electrical Complex of a Transport Vehicle
Authors: Fedorov E , Ferenets A , Mingazov A
Published: November 2021

The article describes the mathematical and software module of computer-aided design of vehicle electric systems: selection and verification of protective devices. The following problems are solved: calculation of currents in the circuit sections of scheme for normal and directive modes taking into account the changes in the current distribution as to the modes of consumption, calculation of the currents in the circuit sections of design scheme for short-circuit modes, checking the correct choice of protection devices as to the rated current, checking the correct selection of protection device in overloads in case of electric motor loads, determining the sequence of triggering of protection devices in the modes of short-circuit and checking the selectivity of protection, checking the protection devices for resistance to short-circuit currents
Computational and Experimental Method for Assessing the Thermal Strength of High-Loaded Diesel Engines
Authors: Belov V P , Apelinskiy D V
Published: November 2021

The article discusses the reasons of fatigue failure of pistons of high-loaded diesel engines. A deformation-kinetic criterion is proposed, generalized to non-isothermal loading, which allows more correct calculation of the number of thermal loading cycles before the appearance of fatigue damage. For a specific implementation of the proposed criterion, a calculated assessment of the piston stress-strain rate was carried out using the FEM. The boundary conditions for the calculation were obtained by thermometry of the piston head on a non-motorized thermal stand (TS). Comparison of the calculated and experimental values of the number of thermal cycles before the appearance of cracks on the edge of the combustion chamber (CC) of pistons made by casting and isothermal stamping is given.
Experimental Study of a Rotary Heat Exchanger with a Metal Mesh Matrix
Authors: Kostukov A V , Kosach L A , Dementiev A A
Published: November 2021

This paper describes the experimental study of a metal mesh matrix of a rotary heat exchanger model including calculation of its regeneration ratio. Temperature oscillograms showing the temperature in tne matrix channel are shown Also the pressure loss value is found for channels of the matrix. The pressure loss value for the case of having a matrix formed by flat metal plates was also calculated in order to compare the calculated values with the ones obtained experimentally for the mesh matrix.
Research of Methods of Optimal Design of Special Electric Drives
Authors: Karandey V Yu , Popov B K , Popova O B , Afanasyev V L
Published: November 2021

Problems of optimization of special electrical and electromechanical systems in modeling, creation and design are solved mainly by methods of mathematical programming. The task of mathematical programming is to find extremes of the function of many variables in the presence of restrictions on variables, which creates fundamental difficulties. To solve such problems, the number of methods for solving the general problem of mathematical programming is currently expanding significantly. In this regard, the trend in the development of mathematical programming is following the path of highlighting and studying various subclasses of problems. The use of certain specific features of the tasks of the selected subclass creates opportunities for their more effective investigation and solution. Examples of such subclasses give convex, quadratic, linear programming problems, transport-type problems, and others. Geometric programming is also a section of mathematical programming that research a certain class of optimization problems. However, when using geometric programming, you have to apply linear, nonlinear programming, the concept of convex programming. Using optimization methods will allow you to correctly investigate, design and create special electric drives.
Research of the Stegosignal Propagation through the Acoustic Environment
Authors: Statsenko L G , Durneva U A , Klescheva N A , Bernavskaya M V
Published: November 2021

The paper considers two main applications of stegosystems: as a digital watermark, for copyright protection, and as a method for secretly transmitting information through an acoustic environment. A stegosystem is studied theoretically and experimentally when information is transmitted over different distances in an acoustic medium in the presence of extraneous noise. Nowadays great attention is paid to the protection of intellectual property. Illegal distribution of media content, including copies of musical compositions, is widespread and reaches unprecedented proportions. Protecting audio files from unauthorized copying and using becomes increasingly important. Digital watermarks are a promising method for solving this problem. The purpose of the article is to develop an effective method for protecting audio files from illegal use by embedding a digital watermark (DW). After detection the illegal distribution of their product, the copyright holder will be able to track the presence of the digital watermark and apply to the court for damages.
Analysis of Physics Learning Outcomes in Eleventh Grade Natural Science Students of Public Senior High School in Palembang After Using E-Learning During COVID-19 Pandemic
Authors: Zaki Ahmad , Sinaga Parlindungan , Kaniawati Ida
Published: November 2021

The purpose of this study was to determine the comparison of student learning outcomes after carrying out Physics learning activities using e-learning during COVID-19 pandemic. This type of research is descriptive qualitative with a comparative method. The sampling technique was simple random sampling with three public senior high schools in Palembang, as many as 360 eleventh grade natural science students in two classes of the first semester in the academic year 2019/2020 and 2020/2021. The instruments used are interview guides and documentation studies. Analytical techniques using a review of the study documentation assessment of each basic competence of Physics in the first semester of eleventh grade natural science and interviews with same Physics teacher in different academic years. From the results of documentation studies in three public senior high schools equally have significant differences in minimum competency standards for Physics material of elasticity from different academic year, also the results of interviews with the teacher this result happened because many students did not understand and had problems working on the assignment, besides that there were more obstacles in online learning compared to offline learning.
Cooperative Learning Model in Science Online Learning for 9th Grade Students
Authors: Namira Nur Rachmadewi Shafa , Luthfiyah Nurulita Hana , Nur Filhak Rakhil , Az Zahra Salsabilla , Pemanasari Anna , Eliyawati
Published: November 2021

Many instructional strategies play an important role in science learning, especially for cooperative learning. This research study is to observe and analyze how the student cooperates in teaching and learning of science in online learning. This research used qualitative research methods, and observation and interviews as a tool to collect the data. The observations were conducted at an international junior high school in Kota Bandung, included 15 female students and 1 teacher as participants. Instruments of research that we used are the rubric of the teaching-learning process, the rubric of student activity, and the rubric of the cooperative learning model. From the data analysis, the learning model used in this online class meeting is proper enough for it is fulfilled the syntax of cooperative learning. So Cooperative learning models can be a good way to teach much content at a time effectively. However, managing students to be more active is needed in the learning process.
Development of character survey instruments in national assessment of Indonesia for physics teachers
Authors: Suhendi HY , Mulhayatiah D , Nasrudin D , Ardiansyah R
Published: November 2021

Abstrak

In order to support the realization of the aspiration to build character as mandated in Pancasila and the Preamble of the 1945 Constitution and to overcome current national problems, the Government of Indonesia has made character education one of the priority programs for national assessment. This is a challenge for educators, teachers and education practitioners to make it happen. However, until now there has been no instrument capable of measuring character. This study aims to determine the development process and the feasibility and benefits of a character survey instrument which is part of a national assessment that must be implemented by teachers to students in schools. The research method used is a development research method with the ADDIE research design coined by Dick and Carry. This research was conducted at several schools in West Java with a sample of 10 physics teachers who were selected by purposive sampling technique. The results showed that the character survey instrument is a valid and reliable instrument with a high category. So, it can be concluded that this character survey instrument is an instrument that is suitable to be used for assess and identify the character of students.
Gases Theory Representation Instrument (GeTRI): A Practical Tool To Analyze Sundanese Students’ Conception in the COVID-19 Pandemic
Authors: Purwanto M G , Gitnita S , Riani V R , Devialita A , Nurjanah A , Hendriyani D , Suhandi A , Samsudin A
Published: November 2021

This research purposes to promote a Gases Theory Representation Instrument (GTRI) as a tool to identify the students’ conception on kinetic theory of gases. The method used in this research was FODEM (Formative Development Methods) model which has three comprehensive steps, which are need analysis, implementation, and formative evaluation. The participants involved in this research were 26 high school students in Sundanese tribe. The students’ responses were analyzed using Rasch model, which involved item reliability, person reliability, validity, difficulty level and students’ conception distributions. Students’ conception were classified into six categories which are Sound Understanding (SU), Partial Positive (PP), Partial Negative (PN), Misconception (MC), No Understanding (NU), and No Coding (NC). Based on the data analysis, it can be concluded that students’ conception are typically in the SU and PP categories. Besides, the Gases Theory Representation Instrument (GTRI) is reliable and valid to identify students’ conception on kinetic theory of gases.
Identification of students’ difficulties in understanding of vector concepts using test of understanding of vector
Authors: Latifa B R A , Purwaningsih E , Sutopo S
Published: November 2021

This study is aimed to identify students’ difficulties in understanding vector concepts in physics because many students think that vector concept is very difficult to understand. This research used an embedded approach research design with quantitative descriptive methods and the sampling used a random sampling technique. Total sample of 142 students from two different schools in Central Lombok district. Test of understanding of vector (TUV) used to test the understanding of students consist of 20 item questions, then followed by interview session with several students. Kruskal-Wallis non-parametric descriptive and inferential statistic was used to performed data analysis. The results of this study indicate that (i) students’ ability to understand vector concepts is still lacking and tends to be very lacking; (ii) the most difficult items for students are the unit vector graphic representation and the graphical representation of vector multiplication. The concept of vector is still considered very difficult for students, especially if the item questions use graphical representations. For further researchers, it is better to conduct a study related to what kind of learning system can support and reduce the difficulties faced by students in learning vector concepts especially on graphical representation.
Need analysis for developing of a light waves module: a three-dimensional learning framework
Authors: Wandana I A P , Efendi R , Ramalis T R
Published: November 2021

Some meaningful changes in science learning standards are listed in A Framework for K-12 Science Education and Next Generation Science Standards: For States, By States under a three-dimensional learning framework. Learning modules must be developed with the framework as the most advanced science learning standards. The research focus was to determine student needs for developing light waves module based on a three-dimensional learning framework. This study involved 147 respondents consisting of 22 teachers with different backgrounds and 125 high school students in the Purwakarta Regency. The instrument used was a 3DLQP questionnaire which included initial knowledge of the three-dimensional learning framework, learning modules in the school, criticism, and suggestions. Data obtained from questionnaires, interviews, national curriculum documents, NGSS complementary documents and then analyzed using triangulation of data sources. Based on the results, the teacher and student responses explain the need for the development of learning modules. This learning module is expected to facilitate the development of coherent and interconnected student knowledge, so that it can be used in various situations of everyday life.
Student needs for developing light waves test based on three-dimensional learning frameworks
Authors: Aziizah U , Efendi R , Muslim M
Published: November 2021

Abstrak

The Framework for K-12 Science Education and NGSS: For States, By States represent a substantial change in science learning standards in the form of a three-dimensional learning framework as the latest science learning standard. The purpose of this study was to analyze the need for a test development based on a three-dimensional learning framework on the topic of light waves in high school. The research subjects were 140 respondents consisting of 20 teachers and 120 students in the high school of Purwakarta area. The research used a 3DLQP questionnaire as an instrument, which accumulates respondent characteristics, prior knowledge of three-dimensional learning, tests used in school, and criticism and suggestions. Data collection was carried out using interviews, questionnaires, national curriculum documents, and NGSS documents. Data analysis utilized the triangulation of data sources. The study results were to elaborate student needs for developing tests and assessment rubrics from the teacher and student perceptions. This research also produces characteristics of test development that are adapted to the national curriculum.
Utilization of wood sawdust as heavy metal adsorbent in paint industry waste
Authors: Sukmawardani Y , Pitriani  , Pitriana P , Subarkah C Z
Published: November 2021

Abstract This study aims to utilize wood sawdust waste in the paint industry waste treatment. The first thing to do is a qualitative analysis of heavy metals before and after the processing. Furthermore, the parameters measured are temperature, pH, TDS, and dissolved oxygen (Dislove Oxgen). The use of wood sawdust as a heavy metal adsorbent in paint industry wastes is able to provide efficient results with no sediment formation when conducting qualitative analysis of Cu2+ and Cd2+ metal ions and raising the waste parameters to be environmentally friendly. This shows that the adsorption process works optimally.
Literature review as a didactical content analysis: Sustainable magnetic lubricants based on ionic liquids
Authors: Jalil S A A , Mudzakir A , Hernani
Published: November 2021

Magnetic lubricants are usually petroleum-based, but not renewable and cannot be environmentally degraded. It can cause the environmental problems. Magnetic lubricants based on ionic liquids can be environmental friendly. The ionic liquid lubricants are synthesized from vegetable oil fatty acids, which is a locally sustainable and renewable sources. This molecular engineering can be used to integrate the concept of sustainability into teaching and learning. This study aimed to obtain the concept map and teaching learning sequence (TLS) from the scientist’s conception. The method used is a qualitative content analysis (literature analysis type), using an instrument in the form of a content analysis format. The first phase begins with collecting literatures in the form of textbooks, monographs, review results and research articles. The next phase is descriptive analysis, selecting categories, and evaluating the material didactically. This research produces the concept map, TLS and clarified chemical concepts. The scientist’s conception obtained is the application, function, characteristics of media magnetic lubricants, ionic liquids and examples of magnetic lubricants based on ionic liquids. Concept map and TLS can illustrate the relationship between one concept and another. They also show the relationship between science, technology and engineering. The results can be used as the basis for the preparation of teaching materials and didactical designs for teaching and learning.
Preparation of silver nanoparticle by green synthesis and application to leather in enhancements of antimicrobial activity of leather
Authors: Rohaeti E , Putri A , Budiasih K S , Ariyanti N A , Annisa A S N , Kasmudjiastuti E
Published: November 2021

The objectives of this study were to prepare nanoparticle by using extract of Tectona grandis L. leaf and to deposit nanoparticle on goat leather via ex situ method, and also to characterize the antimicrobial activity of modified goat leather. The stages in this study were preparing of silver nanoparticles via green synthesis method by using extract of teak leaf, characterizing of nanoparticle by using a UV-Vis spectrophotometer and Particle Size Analyzer (PSA), impregnating the nanoparticle on the pickle leather by ex situ method, and analysing the antibacterial and antifungal activities of modified leather by the diffusion method. The silver nanoparticles were greenish brown in colour, having absorption at the wavelengths of 449 nm which indicator the formation of silver nanoparticles. The silver nanoparticles have an average particle size of 109.9 nm. The results of antimicrobial tests against the bacteria Staphylococcus epidermidis DNCC 6018, Escherichia coli FNCC 0047, and the fungus Candida albicans ANCC 0048 showed that all variations of the leather have different abilities in inhibiting the growth of the bacteria and the fungi. The pickle leathers after modification with nanoparticle Ag showed the highest antibacterial activities against Staphylococcus epidermidis DNCC 6018 and Escherichia coli FNCC 0047.
STEAM-based project learning: the effect to middle school’s student’s collaboration competences
Authors: Nurramadhani A , Kumala F , Permana I
Published: November 2021

The Purposes of this research is to investigate the student’s collaboration competence in integrated STEAM learning approach. The method that is used in this research is pre-experimental design with type one shot case study. The subject that is included in this research is students of VIII grade at one of Junior High School in Depok. The Instrument in this research to take the data is using Co-Measure rubric based on Hero’s research. The rubric has four categories, there are: 1) Students Interaction- 2) Positive Communication- 3) Multi Inquiry- and 4) Interdisciplinary Approach. The data technique sampling is used observation during the activity. Data analysis in this research is used add the score average in each category, then describe it with the description Need Work, Acceptable, and Proficient. This research results are the collaboration competence category which has higher results is transdisciplinary approach and positive communications with proficient descriptions. Arts in STEAM has influence the collaboration, communication, cross disciplinary, and curiosity in learning. This study could be concluded that student’s collaboration competence has outperformed in STEAM project activity rather than in non-STEAM project activity.
The integration of STEAM-project-based learning to train students critical thinking skills in science learning through electrical bell project
Authors: Rahmawati Y , Adriyawati  , Utomo E , Mardiah A
Published: November 2021

This study uses qualitative methods describing the integration of STEAM-project-based learning with the aim of training the critical thinking skills of 18 male and 18 female students in science learning. The application of STEAM is done by integrating it with a project-based learning model on the topic of energy transformation through the electric bell project. Instruments are used to explore the development of critical thinking skills through interviews, observations, reflective journals, and critical thinking skills tests. The study found that students trained STEAM-PjBL to ask questions and have a good understanding of the energy change from electrical energy to sound energy. In addition, through problem solving and project creation, students are encouraged to connect ideas, make assumptions, and infer concepts. The challenges faced in this study are time management, project ideas related to teaching concepts, and student engagement. In addition, STEAM-PjBL integration provides an opportunity for teachers to develop their competencies in applying various methods to encourage students in the test results of the test is students achieve mastering (40%) and competent (30%) at a critical level. Only temporary small (3.80%) students no concept of transformation correctly, even after knowing the distance.
Hybrid SARIMA-FFNN model in forecasting cash outflow and inflow
Authors: Monica M , Suharsono A , Otok B W , Wibisono A
Published: November 2021

The monthly inflow and outflow of money from an area is one of the important concerns in the economic life of a region. This study aims to model and predict the monthly cash inflow and outflow of Kediri, East Java Province, Indonesia using the Hybrid Seasonal Autoregressive Integrated Moving Average – Feedforward Neural Network (SARIMA-FFNN) model. Seasonal time series data from monthly cash inflow and outflow of Kediri are used to test the forecasting accuracy of the proposed hybrid model. First, both variables are modeled using the SARIMA model. Then, non-linearity testing was carried out on the best SARIMA model for each variable and the results showed that only cash inflow was non-linear. Therefore, only cash inflow could be continued with the FFNN model. The best selected model was the FFNN model with the input SARIMA(0,0,0)(1,0,0)12 with five hidden layers. The input of FFNN modeling was based on the best SARIMA model with only the autoregressive order which for non-seasonal and seasonal. The sum of hidden layers was chosen by the smallest values of MAPE and RMSE. Forecasting results with the hybrid SARIMA-FFNN model on data testing followed the actual data pattern.
Spatial autocorrelation analysis of Covid-19 cases in South Kalimantan, Indonesia
Authors: Amaliah O N , Sukmawaty Y , Susanti D S
Published: November 2021

Coronavirus Disease 2019 (COVID-19) is a new coronavirus that was discovered in Wuhan, China, at the end of 2019. In March 2020, the outbreak extended throughout the world, including Indonesia and one of its provinces, South Kalimantan. This rapid expansion should belinked to people’s mobility between regions, hence the linkage across regions must be examined. In South Kalimantan Province, the purpose of this research is to evaluate the distribution and relationship across regions in terms of the number of positive COVID-19 cases, the number of additional positive COVID-19 cases, and the number of COVID-19 patients under treatment. The spatial autocorrelation analysis with the Moran Index and Local Indicator of Spatial Autocorrelation (LISA) tests were used to determine the spatial autocorrelation between what and what using what data/where the data obtained? from March 22 to September 30, 2020. Based on the results of the Moran Index test, it is known that there is a spatial autocorrelation in the number of cases, the number of additional cases and the number of positive confirmed COVID-19 patients in treatment between one region and another neighboring area. While the results of the LISA Index test show that Balangan Regency, Hulu Sungai Tengah Regency, Hulu Sungai Utara Regency, Banjarmasin City, Tabalong Regency and Banjar Regency affect the level of COVID-19 cases in their respective neighboring areas. Therefore, there is a need for policies to control community mobility in those spatially correlated areas and increase testing and tracing to control the spread of COVID-19 cases in South Kalimantan Province.
A note on the refinement of Hermite-Hadamard inequality
Authors: Idris Mochammad
Published: November 2021

In this paper, we give the sharper bounds for the mean value of a convex function using dyadic decomposition. Our result is related with classical Hermite-Hadamard inequality. Moreover, using the result, we can determine the maximum error before calculating the numerical (trapezoidal) integral of the convex function.
Forecasting of fuel oil supply using the transfer function approach (Case study: PT. Agrabudi Karyamarga Gas Station Division 64.706.07)
Authors: Labibah A U , Sukmawaty Y , Susanti D S
Published: November 2021

In everyday life, fuel oil is quite important. The need for fuel is increasing every day, which means that the supply of fuel oil must keep up with the demand. As a reason, we require a way for predicting future fuel needs. The forecasting method is one that is frequently utilized. Forecasting is a method for predicting future conditions based on historical data. The transfer function approach is one way to forecast data with several variables in time series analysis. The objective of this research is to estimate the parameters of the transfer function model and use a transfer function approach to predict the movement of fuel, particularly pertalite. The parameter estimation results in this research areω^0=0.033;ω^1=−0.0358;ω^2=0.0627;δ^1=−0.9713;δ^2=1;θ^1=−0.9141, and the forecast value for the 214th period is 8762.61, based on the data used, namely for 213 periods starting from the 1stperiod until the 213thperiod.
Modeling of poverty in Kalimantan with nonparametric spline regression approach
Authors: Halida A , Salam N , Lestia A S
Published: November 2021

Poverty is a problem that is always present in any country, including Indonesia. Kalimantan is one of the islands in Indonesia that has not been free from poverty. Therefore, more effective efforts to further reduce poverty are needed. The purpose of the is study was to develop a model that can explain significant factors to poverty in Kalimantan. To achive the objective, first, factors that may have significant influence to the changes in the percentage of poor people should be identified, using regression analysis. In this study, nonparametric regression analysis was used with a spline approach since the relationship between poverty and the explanatory factors did not have a particular pattern. The results of this study showed that, the best was using three knot points, where Open Unemployment Rate (OUR), Human Development Index (HDI), and Economic Growth have a significant effect on poverty in Kalimantan.
Analysis of rainfall classification over Tanah Laut disrict based on global climate indicators using support vector machine method
Authors: Hayah N , Soesanto O , Rahman M A
Published: November 2021

The Support Vector Machine (SVM) classification method can be applied in various fields, one of which is meteorology and climatology in rainfall forecasting. Thus, a study was conducted by classifying rainfall to recognize the relationship between global phenomena and rainfall and the results of applying the classification using the SVM method to rainfall in the Tanah Laut Regency. The analysis is carried out using the SVM Multiclass concept with 4 categories of rainfall classification: low, medium, high, and Extreme. The kernel used in SVM is the RBF kernel with optimization parameters used, namely Cost (C) 1,5,10,15 and Gamma (γ) 1,5,10,15. The dataset formed is based on the annual period, climatic conditions, and seasonality. The Spearman Rank correlation test describes the relationship between global phenomena and rainfall with a correlation range of (−0.1456 ) − (0.43144) for the entire dataset. The implementation of the SVM classification method shows that the Cost (C) 10 and Gamma (γ) ≥ 5 parameters obtained the highest accuracy of 100% on the training data. In contrast, in testing the data testing, the accuracy was good, namely the accuracy of 78.00% in La Nina and 81.38% in seasonal periods.
Constructing an optimum 4×4 S-Box with quasigroup
Authors: Pambekti G B , Rosdiana S
Published: November 2021

The efficiency of cryptographic algorithms is a problem that is often encountered. One solution of this problem is the use of lightweight cryptography. S-Box is one of the basic non-linear components in a cryptographic algorithm. Among all, 4 × 4 S-Box quasigroup is one kind of S-Box which can be used in lightweight cryptography, that formed by applying quasigroup transformation. The research described in this paper is the construction of the 4 × 4 S-Box using e-transformation of quasigroup as well as to know which leader pattern produces the highest number of optimum S-Box and mostly has higher Robustness value. The construction resulted in 6912 4 × 4 S-Boxes quasigroup by applying for each six leader patterns in four e-transformation rounds of 432 nonlinear quasigroups. The results of 4 × 4 S-Box quasigroup is calculated based on criteria of optimum 4 × 4 S-Box that has higher Robustness value. From all results of the 4 × 4 S-Box quasigroup, it is known that the leader pattern producing S-Box which meet the criteria and all S-Boxes have highest Robustness value are l
1
l
2
l
1
l
2 and l
1
l
2
l
1
l
2. The number of S-Box which meet the criteria is 18,75% of the total 5376 different 4 × 4 S-Boxes quasigroup and the highest Robustness value is 0,75.
Relation between the left and right cosets of an α-normal subgroup
Authors: Mahatma Y , Hadi I , Sudarwanto
Published: November 2021

Let G be a group and α be an automorphism of G. In 2016, Ganjali and Erfanian introduced the notion of a normal subgroup related to α, called the α-normal subgroup. It is basically known that if N is an ordinary normal subgroup of G then every right coset Ng is actually the left coset gN. This fact allows us to define the product of two right cosets naturally, thus inducing the quotient group. This research investigates the relation between the left and right cosets of the relative normal subgroup. As we have done in the classic version, we then define the product of two right cosets in a natural way and continue with the construction of a, say, relative quotient group.
Subordination of functions in subclass of Bazilevič Functions B
1(α, β)
Authors: Marjono
Published: November 2021

Let f be analytic in the unit disc D = {z : |z| < 1} with

f
(
z
)
=
z
+

∑

n
=
2

∞

a
n

z
n

, and for α ≥ 0 and 0 < β ≤ 1, let B
1(α, ß), denote for the class of Bazilevič functions satisfying the expression

|
arg

z

1
−
α

f
′

(
z
)

f

(
z
)

1
−
α

|
<

β
π

2

. We give sharp estimates for various coefficient problems for functions in B
1(α, β), which unify and extend well-known results for starlike functions, strongly starlike functions and functions whose derivative has positive real part in domain D.
Prime labeling of line and splitting graph of brush graph
Authors: Fran F , Putra D R , Pasaribu M
Published: November 2021

A bijective function f from V(G) to {1,2,…, n} be a prime labeling of a graph G with n order if for every u, v ∈ V(G) such that e = uv ∈ E(G), f(u) and f(v) relatively prime. A prime graph is a graph which admits prime labeling. In this study, we investigate and conclude that the line and splitting graph of the brush graph is a prime graph.
Application of GSTAR(1,1) model for layer peat soil predicted based on resistivity log data
Authors: Jonathan R , Yundari  , Nurhasanah  , Nada O Y E
Published: November 2021

In this study, GSTAR modeling was carried out with the inverse of distance weight matrix obtained from Geoelectrical Resistivity data at several peatland locations around the Universitas Tanjungpura, Pontianak. This data can identify the subsurface layer of the soil through the electric current that binds into the soil. However, due to the limitation of the tool to measure the resistivity value, it can only measure 1/5 of the depth of the observation length. To overcome this problem, predictions are made at the next depth using the GSTAR model. The study began by measuring the resistivity value of the land using the geoelectric method and mapping it. Through this GSTAR modeling, predictions are made for the unobserved subsurface to determine the type of soil layer. Knowing the type of deeper soil layer can help contractors build plant concrete stakes to keep buildings safe on peatland. The results of the GSTAR(1.1) model are not accurate enough to estimate the resistivity value data. This is possible because the correlation between rock ages is not the same, so further analysis is required.
Temporal analysis of the heavy metal concentration in road sediment and dust using statistical models
Authors: Zafra-Mejía C A , Rondón-Quintana H A , Echeverry-Prieto L C
Published: November 2021

The objective of this paper is to show a temporal analysis using autoregressive integrated moving average models of the heavy metal concentration in road sediment and dust of Soacha, a Colombian locality. The representative size fractions in the road sediment and dust were <250 μm and ⩽10 μm, respectively. The results suggest that lead is the best metallic element to study the relationship between the heavy metal concentration in the road sediment and dust (r-Pearson = 0.90). Univariate models (R2⩾ 0.58) suggest that the time series of lead concentrations in road sediment and dust have the same temporal structure. Namely, because they are first-order autoregressive processes, concentrations at a given moment of time are influenced by the immediately preceding concentrations. The transfer function model (R2= 0.91) suggests that there is no delay in impulse transfer from road dust concentration to lead concentration in the road sediment. The effect is immediate for a sampling interval of 3 days. The results show that modeling has a better fit during the rainy season compared to the dry season. In the context of the simulation of physical phenomena in engineering, this study is relevant to deepen knowledge in relation to the use of autoregressive integrated moving average models.
Bottom rack intake improvement as a fluid physics application through a computational fluid dynamics model
Authors: Calderón H E , Rada L M , De Plaza J S
Published: November 2021

This research focuses on improving the hydraulic behavior of a traditionally design bottom rack intake, from variations in roughness parameters, free height, and the inclusion of chamfers, establishing a contribution to the contrast between classical physics and the physics that takes over the partial resolution of the Navier-Stokes equations. To make possible the structure in OpenFOAM, it is necessary to use the geometric tool Salome-Meca, as well as a meshing tool (snappyHexMesh), and the InterFOAM solver in the processing stage. In the same way, through the turbulence model (K-E) local effects are evidenced in the Fluid-Structure interaction, as well as the identification of events and the development of the phenomenon of vorticity. The results show the improvement presented in some areas of the structure from the stabilization of the water flow through of the fluid-structure interaction change, the modification of the geometry and roughness, minimizing the presence of vertical vortices, cavitation, and surrounding areas. This allows us to conclude that traditional hydraulic do not consider the real physical flow behavior within the structure and neither the subsequent phenomena that develop, establishing as a starting point the need to rethink the design of the bottom rack intakes.
Design of a mechanical pedal valve to improve the use of water in plumbing systems
Authors: López Uribe L F , Sánchez Rincón C S , Díaz Jiménez M , Flórez Solano E
Published: November 2021

The use of water is a very important economic and environmental factor in all industrial sectors since the improvement in its use offers an optimization of this resource. The waste of water usually causes damages firstly to the environment by the supply sources, then to the industries by its high demand and to the hydrosanitary sources that the houses have. The valves have some control that allows a more comfortable use of this resource in sinks that provides some savings. Currently, there are valves that usually replace the traditional ones due to their automatic and/or mechanical operation, which allows for innovation and savings of this resource. In this sense, this research is oriented to the design of a mechanical pedal valve that allows a more comfortable and controlled control, thus granting the operator control in an immediate way, without wasting the fluid in the middle of the washing and avoiding a manual contact that in a certain way dissipates the risk of contagion of diseases such as Covid-19 by direct manipulation. An analytical methodology supported by computer aided drafting programs such as Ansys Fluent and SolidWorks was used. Finally, it was determined that, for the dynamic and static studies, the designed valve complies with the Colombian technical standard and the static design factors.
Physical and mechanical behavior of fine soil according to the content of multispecies diatoms
Authors: Zuluaga D A , Sabogal D , Buenaventura C A , Slebi C J
Published: November 2021

The physical response and geotechnical properties of diatomaceous soils are not fully understood, data are sparse, and do not account for the effects of single and multispecies frustule content, origin, type, and variability. The main physical problem lies in the irregular response of diatomaceous soils due to micro and nano scale causes and its unexpected effects on the macro scale. This research compared the characteristics of a multispecies diatomaceous soil sample (North American origin) with other diatomaceous single-species soils. Six artificial soil mixtures were prepared, dosed by weight, in order to determine the influence of the content of frustules. The results show that the liquid limit of the samples is lower than that of the monospecies samples for any content of frustules. The pore areas of the monospecies samples are found to be 4 to 7 times larger than those of the North American soil. Void ratios and compressibility ranges are higher as the diatom content increases. The internal friction angle of diatomaceous soils varies in a non-linear tendency with respect to fossil content. For the studied soil at 100% fossil concentration, the internal friction angle reached 38.32°, a magnitude that is lower than the values reported for most of the monospecies contrast samples.
Attitudes towards physics. A study with high school students from the Colombian context
Authors: Hernánez-Suarez C A , Gamboa-Suárez A A , Suarez O J
Published: November 2021

Science education should promote the development of competent students in science and develop their interest in science; however, although the role and relevance of science within society is evident; the interest towards it is not conscious, being the negative attitudes of the students the main problem in the teaching of physics, which translates into a deficient knowledge and lack of scientific vocation. This report aims to diagnose the attitudes of students in high school physics courses. The study was developed through a non-experimental, descriptive research design, obtained from the application of a Likert scale that evaluates attitudes towards physics, adapted and validated to the context of students in an educational institution in Colombia. The results indicate that the attitudes of the students are slightly favorable, which is an empirical precedent to continue with the studies on attitudes towards physic. This should be considered to enhance the learning processes in these students, especially for those who have their first approach to physical concepts and give importance to attitudes when teaching.