bluuebunny/crossref_metadata_2025 huggingface dataset:
Practically Examining the Effect of Thermal Loads on Curved Tubes Made of Different Natural Composite Materials
Authors: Jassim Riyadh Fakher , Abdulla Fadhel Abbas
Published: February 2021

This paper examines the effect of changing temperature on the curved natural composite material pipe (Walnut husks powder with polyester) and curvature angle θ= 34° practically. This work involves the design and fabricates of curved pipe samples with an angle of curvature θ=34° at 50 % weight fraction. Also, tensile and thermo-mechanical test were performing to find the mechanical properties of the specimens. Experimental work included design and manufacturing test rig to simulate thermal stress. The experimental results revealed that a maximum hoop strain and longitudinal strain increased with increasing the temperature. The hoop stresses at crown and intrados positions were more than the hoop stress at extrados position by 150.762% and 138.363% respectively, and the von mises stresses at crown and intrados positions were more than the von mises stress at extrados position by 218.259% and 178.193% respectively. In the curved pipe, the hoop strains at intrados and crown positions were more than the hoop strain at extrados position by 114.583% and 60.416% respectively.
Evaluate the Performance of Jalan Otista Bandung with on-Street Parking
Authors: Fadriani Hetty , Afiyah Salamatul , Liklikwatil Yakob , Haris Samun , Hidayat Iman , Hidayat Rahmad
Published: February 2021

Road performance is the ability of a road to serve traffic flow which can be determined by its capacity, free-flow speed, and degree of saturation. The performance problem of Jalan Otto Iskandar Dinata (Otista) Bandung, which is located in an office and trade area, occurs due to high side activity, namely on-street parking marked by congestion. Analysis conducted using the Indonesian Road Capacity Guidelines (PKJI 2014) to the traffic data collected on weekdays and weekends. This research tries to find a solution by eliminated on-street parking. The existing condition shows the volume on weekend at noon at 3242 pcu/hr, side friction is classified as very high with the proportion of on-street parking at 76%, spoot speed of 12 km/hr, the free flow speed of 36.89 km/hr, a capacity that occurs is 3324 pcu/hr, and degree of saturation is 0.98 with the level of service E. The road performance improvement scenario is carried out by setting on-street parking which gives the free flow speed value greater than the existing condition, class of side friction becomes very low, increased capacity, degree of saturation below 0.85 as determined by PKJI 2014 by improving the level of service to C.
Transmission Coefficient Testing on Sweatbatching Model with Artificial Reef Brick-1 Armor
Authors: Mahardika Andrew Ghea , Ramady Givy Devira
Published: February 2021

In Indonesia, planning ocean breakwater (breakwater) has not been done because of the expensive construction costs, while Indonesia is a country that has the fourth-longest coastline in the world and there are plenty of beaches due to damage from waves. This issue is of interest to researchers for study. The purpose of this study was to determine the characteristics of the wave transmission coefficient when using an armor breakwater sink with a brick-first artificial reef. Tests on laboratory models and multiple linear regression analysis methods are used to look at some of the variables expected to affect the size of the transmission coefficient (Kt). Of the model used the results showed that the wave comes (Hi), height (h), and width of the structure (b) of the breakwater, the water surface distance (F) with the breakwater where all variables are divided by gT2, significantly influence the transmission coefficient.
Anti Fuzzy Line Graphs
Authors: Nusantara Toto , Rahmadani Desi , Asmianto  , Trisanti Yuliana , Bin Gani Abdullah
Published: February 2021

In crisp graphs, if a graph G is given then we can define line graph L(G) of it. In a similar way, for a given fuzzy graph, we can determine its fuzzy line graph. A number of important results about fuzzy line graphs have been obtained. However, study of anti fuzzy line graphs is still open. Motivated by this, we are interested in studying anti fuzzy line graphs. In this paper, we define the concept of anti fuzzy line graphs. We derive a necessary and sufficient condition for an anti fuzzy graph to be isomorphic to its corresponding anti fuzzy line graph. We investigate when an isomorphism between two anti fuzzy graphs follows from an isomorphism of their corresponding anti fuzzy line graphs. We conjecture a necessary and sufficient condition for an anti fuzzy graph to be the anti fuzzy line graph of some anti fuzzy graph. In particular, we give some result related to regular anti fuzzy line graphs.
DNA Amplification of Methanogenic Bacteria from The Sewage of Coconut Water by Specific Primer 16S rRNA and Specific Methanogenic Gene
Authors: Kapahang Ardi , Bintang Maria , Solihin Dedy D
Published: February 2021

This study aims to transform metanogenic bacterial plasmid into E. coli C600 and to identify the products of methane from E. coli transformants. Isolate of methanogenic bacteria from cow’s feces as a positive control, named A and B. The transformation of isolate from the sewage of coconut water (P and M) plasmid to E.coli C600 using “Blind Test” method Fermentation of coconut water by E.coli transformant that yield gas was quality-analyzed by burning and quantity-analyzed by GC. The result of gen 16S rRNA analysis by PCR, there is a similarity of nucleotide around 1088 bp, which is the same as isolate A and B from cow’s feces. The result of gen mcrA’s PCR on isolate P, M and isolate A and B have the similarity of nucleotide which is around 600 bp. The sequencing of gen 16S rRNA isolate P yielded nucleotide with composition respectively G 31.25%, C 20.58%, A 27.11%, and T 21.04% while the isolate M with composition respectively G 31.25%, C 20.31%, A 27.02, and T 21.32%. The identification of isolate M is similar with Clostridium tyrobutyricum (100%) and isolate P is almost similar with Clostridium tyrobutyricum (99%).
The role of information technology on the online learning success based on self-regulated learning data
Authors: Sulisworo Dwi , Maryani Ika , Kusumaningtyas Dian Artha
Published: February 2021

Strategies in Covid-19 mitigation positively acquire changes in individuals’ conduct. Teachers and students hurry to vary their interaction using online learning. In online learning, where learning control is higher in students, self-regulated learning or SRL becomes a fundamental issue to check. This research could be a quantitative descriptive study to elucidate how the SRL profile of scholars in Covid-19 emergencies. The information was gathered using Google Form. The SRL questionnaire covers four subscales: planning (5 items), monitoring (6 items), controlling (6 items), and reflecting (5 items). Profile of SRL is grouped at high, moderate-low, and low SRL compared to the common SRL of all students. However, students as an entire tend to own quite high SRL. So it is often expected that students won’t encounter learning problems by using online learning.
Gamification in Learning using Quizizz Application as Assessment Tools
Authors: Handoko Wiwin , Mizkat Eva , Nasution Auliana , Hambali  , Eska Juna
Published: February 2021

Nowadays, Teaching and learning activities in the world of education must always follow the development of technology. The use of these technologies will make these activities more effective and efficient. Gamification is part of innovation in education. In this research, gamification is used as a tool for studying activities in project management information systems subject. The method used is technology-based applied research. The Assessment Tool in this study uses Quizizz. Quizizz is used on midterms. This exam was attended by 29 students of the information systems department STMIK Royal. The questionnaire was made using a Mentimeter. The use of Quizizz has a positive impact. The level of student answers questions correctly is 51%. Then 66% prefer Quizizz as assessment tool compared to paper and google forms.
Technical Guidance for Learning Management in a Video Conference with the Zoom and Youtube application in the Covid-19 Pandemic Era
Authors: Agusriadi Agusriandi , Elihami Elihami , Mutmainnah Mutmainnah , Busa Yunus
Published: February 2021

Learning conducted by teachers and lecturers will not take place without online management in the current pandemic covid-19. Therefore, the technical guidance organized by LPPM University of Muhammadiyah Enrekang aims to provide teachers and lecturers with understanding and skills on how to manage learning online or online. This stage of research includes analyzing the need for an online learning management platform, conducting technical guidance, and conducting evaluations. After the technical guidance activity, the participants liked the material and speakers in the technical guidance which indicated that the participants understood the material presented by the resource persons. Based on the evaluation results it was found that the implementation of this activity was successful with a high level of attendance of the participants, a level of likeness that was evenly distributed in all material presented by the resource persons, and a very high level of satisfaction with the guidance committee services.
Kahoot Application for Elementary School Students: Implementations of Learning Process from Distance during Pandemic period of COVID 19
Authors: Djannah Mahfira , Zulherman  , Nurafni
Published: February 2021

Kahoot Applications has been one of the media of the learning process to be developed further. It can become media of the learning process as well as a tool for measuring/index of the target. These analyses observe the result of the learning process based on Kahoot Application towards the fifth grade of elementary students in the context of single and complexes theory. This kind of Media of learning process is more likely effective used in the argent situation of the Pandemic COVID 19 period that is inevitable for the mechanism of the learning process from home which should be supported by internet connection. This product is made by the learning development of ADDIE. The method of analysis used is the method of surveying. The Data taken from surveying uses a Likert scale from a score within 1 to 5. They are three expertise from material aspects and the media aspect, 5 teachers from the fifth grade of elementary from different schools, and is examined for 149 students from 5 different schools to examine the result. The result stated that Kahoot’s application as the media of the learning process is efficient and proper being used as a learning and teaching process because Kahoot applications allow enhancing students’ interest and motivations to be more likely focus to on learning process for the better result of learning mechanism.
Factor Affecting E-Learning User Acceptance: A Case Study of AULA
Authors: Effendy Faried , Kurniawati Octa Dwi , Priambada Guntung
Published: February 2021

E-learning is a strategy that is expected to transform ordinary learning into a learning philosophy that can be adapted, shared, reusable, and versatile. Based on previous research, e-learning acceptance is influenced by many factors. However, there are still some things that have not been determined and discussed; Therefore, they need further investigation. Based on previous assumptions, this study is an attempt to examine the factors that influence student acceptance of e-learning at Airlangga University, Indonesia. In this study, the Technology Acceptance Model (TAM) and (Information System) IS Success Model were combined to test intention, user satisfaction, and actual use of e-learning. This research was conducted by distributing online and offline questionnaires to 100 student respondents; then processed the data using SmartPLS 3.0. The results showed that e-learning user satisfaction was influenced by the quality of education, service quality, and information quality. At the same time, the intention to use is influenced by the quality of education. In addition, user satisfaction and intention to use e-learning affect the actual use of e-learning. This research is expected to help decision-makers from higher education to better understand the effectiveness of using e-learning by students.
Teacher’s intention to use online learning; an extended technology acceptance model (TAM) investigation
Authors: Ngabiyanto  , Nurkhin Ahmad , Widiyanto  , Saputro Iwan Hardi , Kholid Al Mamnukhin
Published: February 2021

Pandemic covid-19 requires teachers everywhere to take advantage of online learning. This study aims to investigate the factors that affect the teacher’s intention to use online learning based on the extended Technology Acceptance Model (TAM) approach. The extended TAM developed from the previous research. The population of this study were the teachers at Al Asror Islamic Boarding School. The data was obtained by using a questionnaire. The analytical method used was multiple regression analysis. The result showed that only perceived usefulness and teacher’s readiness had positive and significant impact on teachers’ intention to use online learning. There was negative and significant influence of perceive of ease of use on teachers’ intention to use online learning. Prior experience and computer knowledge didn’t have significant impact. The results also showed that prior experience and computer knowledge had a significant and positive effect on perceived ease of use and perceived usefulness. Teacher’s readiness was the most dominant factor among other variables.
LMS-Google Classroom Digital Platform: Impact on the Critical Thinking Ability, Self-Concept, and Mathematics Anxiety of Pre-Service Mathematics Teachers During the Covid-19 Pandemic in Indramayu, Indonesia
Authors: Mellawaty  , Taufan Mochammad
Published: February 2021

The purpose of this study was to determine the effect of self-concept and mathematics anxiety on the ability to think critically pre-service teachers of mathematics at the time of a pandemic Covid-19 in Indramayu, Indonesia with used digital platforms LMS-Google Classroom. This type of quantitative research uses one group pre-test post-test design. By using the purposive sampling technique, the research sample taken is the fourth-semester students who take the Abstract Algebra of Theory Ring course as many as 19 people. Research instrument in the form of critical thinking skills tests, self-concept questionnaires, and mathematics anxiety. Data analysis using ANOVA test. Based on the results, there is a direct influence self-concept and mathematics anxiety on the ability to think critically pre-service teachers of mathematics at the time of a pandemic Covid-19 in Indramayu, Indonesia by using a digital platform LMS-Google Classroom. There are other findings obtained, namely: the readiness of the lecturer in preparing the learning process must be very correct and can add applications that can face virtual eyes with students, such as the use of Zoom Meeting; the readiness of pre-service teacher in following the lecture process in the form of stable internet use because 90% of pre-service teacher come from the border area of Indramayu district and surrounding districts.
Media Information Communication and Technology (ICT) Development Strategy in Education Learning
Authors: Yusuf Achmad , Munif  , Hasyim Mochamad , Anan Asrul , Hadi Muhammad Nur
Published: February 2021

In the era of globalization in the learning process educators are more likely to use media based on information and communication technology (ICT). ICT-based learning media is a tool used in pai learning process by utilizing information technology. This is because the development of ICT has implications for the development of the education system, from the basic level to the higher education level. Some strategies that can be done in the learning process through ICT Development in multicultural-based PAI learning included; Active learning, Collaborative learning, Creative Learning, Integrative learning, and Evaluative learning. Media development with ICT has a purpose; first, the availability of flexibility for students in choosing study time, as well as regardless of stress due to the influence of geographical location. Second, through the ICT facilities available, students are expected to be able to explore and also discover new ideas or innovations from experts around the world. And third, the existence of ICT in the education system allows some enforcement activities, such as the delivery of lectures to students, monitoring the progress of students, and assessments can be done on time.
Temperature Effect on Particulate Matter Concentrations PM 10 during the heating season in Burgas
Authors: Hasan F B , Midyurova B N , Mihalev T M
Published: February 2021

In the present paper, the dynamics of particulate matter (PM) concentration during the heating season was studied with respect to the seasonal dynamics of the temperature recorded at two measuring sites from the National system for monitoring of air quality in Burgas. The automated measuring stations (AMS) selected for the present study are located in Dolno Ezerovo (DE) and Meden Rudnik (MR) in the municipality of Burgas. This study looks at the impacts of Temperature on localised PM10 concentrations in an urban area of Burgas over the winter period. The levels of PM 10 pollution is an important characteristic for the quality of life in urban environment. The main source of PM 10 emissions is considered to be the domestic heating with wood which varies with the values of the temperature during the heating season.
Juniperus waste wood as a source for obtaining pellets by single-screw extrusion method
Authors: Simitchiev A T , Lazarov L V , Fidan H N , Bozadzhiev B V , Stoyanova A S
Published: February 2021

Waste wood (biomass) is one of the most valuable and multifunctional environmental, long term resources of Earth. The aim of this paper was to study the possibilities for obtaining pellets from Juniperus. excelsa M. Bieb. biomass by a single-screw extrusion pre-treatment method. Biomass obtained after aqueous distillation of J. excelsa was used. The sample was grounded and sieved into dp ⩽ 500 μm and dp ⩽ 500 μm particle in size. The experiments were carried out on a single-screw laboratory extruder “Brabender 20 DN”. According to our results, the pellets with dp < 500 μm particle size were characterized with the following indicators: the mass flow rate (1.92 kg/h), sectional expansion index (1.03), specific mechanical energy (215.65 kJ/kg), density of the extrudates (0.44 g/cm3) and volumetric flow rate (4337.58 cm3/h). The samples obtained with dp > 500 μm particle size showed the following characteristics: the mass flow rate (1.30 kg/h), sectional expansion index (1.09), specific mechanical energy (535.23 kJ/kg), density of extrudates (0.48 g/cm3) and volumetric flow rate (2719.78 cm3/h). The biomass was a potential source for biofuel production. Pellets produced from biomass with a particle size dp > 500 μm had a higher density and sectional expansion index than those with a particle size dp ⩽ 500 μm. However, their production was more economically impractical, which is due to their lower mass and volumetric flow rate, as well as higher specific mechanical energy.
Theoretical determination and analysis of the length of the non-working move and of the width of the headland when performing a fishtail turn with a curvilinear reverse move by a machine-tractor unit with a mounted machine in an irregularly shaped field
Authors: Trendafilov Krasimir
Published: February 2021

Machine-tractor units with mounted machines most often perform fishtail turns with a curvilinear reverse move when changing the direction of movement at the end of the field. In an irregularly shaped field, the shape of turn and the width of the headland depend on the angle between the direction of the working move and the field boundary and the direction in which the working moves alternate in the field. The article presents dependences for determining the length of open and closed fishtail turns with a curvilinear reverse move and the width of the headland. An analysis of the influence of the angle between the direction of movement and the field boundary on the length of the non-working move and the width of the headland is made. It has been found that when the unit moves in the field from right to left, the length of the non-working move is the smallest and constant, except in cases where the angle between the direction of movement of the unit and the field boundary is very small. The headland has a smaller width in open turn from left to right and closed turn from right to left. When the angle between the direction of movement and the field boundary is small, the closed turn must be performed when moving in the field from left to right.
Experimental evaluation of the effectiveness of a diesel fuel additive
Authors: Mihaylov V , Ivanov Z , Belchev S , Petkov D
Published: February 2021

One of the ways to reduce carbon emissions is by lowering the energy consumption of vehicles. Electrical or hybrid cars can help for lower emissions from transport in nearby future, but a big step can be achieved now if there is a way to reduce fuel consumption in current fleet. The use of fuels with improved characteristics or use of fuel additives, which can affect fuel physical and combustion properties, are promising measures in this direction. Due to advances in chemistry science and the research done in this area, it is of practical interest what the achievable benefits are nowadays. The aim of this research is to study how a popular present day commercial additive affects the fuel consumption and environmental performance of a high-speed diesel engine. In this paper are shown the results from performed studies on a direct injected diesel engine when working with additive, aimed to improve its energy consumption and hence its reduction in carbon emissions. The results show improvement in some of the harmful emissions, but no improvement of engine’s efficiency.
Influence of the control signal on parameters of low impedance injectors for SI engines
Authors: Mihaylov V , Ivanov Z , Mersinkov H , Stoyanov S , Wrobel R
Published: February 2021

There is high variety of injectors for spark ignited (SI) engines, especially those fitted with additional aftermarket LPG/CNG fuel system. The tendency is for using injectors with lower electrical resistance, because of the faster opening time. But this rise some difficulties, one of which is the higher current, that pass through injector’s coil. One of the most used method to counter fight that is using special control signal. Experiments are conducted with varying parameters of the control signal and its influence over current through the coil, temperature, injector’s opening and closing time. Results show that not only less current and heating of the coil but also faster operating speed of the injector itself can be achieved, as the modulation of the pulse affects mainly the closing time of the valve needle.
Adaptation of a system for pattern design of twist knot draperies for knitted fabrics
Authors: Peneva Tanya , Kazlacheva Zlatina , Ilieva Julieta
Published: February 2021

The paper presents an investigation of pattern making of twist knot drape clothes from knitted fabrics with aim systematization of pattern design on the base of searching for a mathematical dependence between the knot diameter and the widths of the draped pieces in the place of twist. The study is an adaptation of an investigation of development of a system for pattern design of twist knot draperies, made from woven fabrics, for knitted ones. The full systemization of the geometrical constructional approach of pattern making of twist knot drape clothes from knitted fabrics is result of obtaining of dependence between the knot diameter and the widths of the draped pieces in the place of twist on the base of a linear regression. The systemized approach provides easy and correct pattern design with various sizes of the diameter of knot and the width of draped parts. It facilitates the process of fashion design and pattern making and gives possibility for new creative ideas and variety of designs of twist knot drape clothing from knitted fabrics.
Rationale for the development of the design of a microwave installation for cleaning wool yarn in the conditions of modern textile enterprises
Authors: Pryvala Sergei , Pryvala Valeriy
Published: February 2021

In the conditions of fierce competition in the world market of textile materials the important factor is optimization of process of fabrics production. Textiles must be of high quality, inexpensive and competitive. This concept is more or less adhered to by manufacturers of woven materials made of synthetic fibers, which are outwardly attractive and inexpensive. According to the last year’s statistics, the dominant raw material in the production of fibrous materials is polyester. Its share in the world market is several times higher than the share of its closest competitor - wool. However, the cost of textiles based on wool fibers, taking into account its important performance properties, can not be cheap. Sewing products made of woolen materials are always in the trend of modern fashion. Coats, suits, dresses, sweaters, sweaters, blankets, plaids - these are products for the manufacture of which woolen fabrics of various thicknesses, compositions and finishes are traditionally used. Thus, the issue of reducing the cost of textile production technology from wool yarn is relevant for domestic textile enterprises located in Chernihiv, Kryvyi Rih, Odessa, Sumy. However, modern wool cleaning technology remains multi-stage and energy consuming, which affects the quality and final cost of production [1]. Therefore, the purpose of research is to create energy-saving technology for wool cleaning through the use of ultra-high frequency electromagnetic field (UHF) at textile enterprises.
“CloStyler” – mobile application to calculate the parameters of clothing blocks
Authors: Zakharkevich Oksana , Poluchovich Iryna , Kuleshova Svetlana , Koshevko Juliya , Shvets Galyna , Shvets Alexander
Published: February 2021

Due to the COVID19 pandemic that challenged our society with necessity of distance learning it is right to provide educational institutions with tools those would be accessible anytime and anyplace for students. The aim of the current research is to develop an app that will support students studying apparel design as well as their teachers. The prototyping method was used to explore aspects of an intended design of the app. The method of semantic differential was used in order to evaluate the prototype. Comparative analysis of the already existing apps and the developed one was used to determine the level of the app competitiveness. The mobile app “CloStyler” was developed by using MIT App Inventor. Using the app allows achieving the labor productivity growth up to 568.5 %. The reduction of time costs is 29.4-85.0 %. By means of the comparative analysis of the apps those are already on the market and the developed app “CloStylef” it was determined that “CloStyler” is better suited and better equipped for the task of computing the parameters of the basic blocks of clothing.
Analysis of the smart clothing technologies in dance costume designing
Authors: Poluchovich Iryna , Zakharkevich Oksana , Kuleshova Svetlana , Koshevko Juliya , Shvets Galina , Shvets Alexander
Published: February 2021

In past decade fashion world as well as world of technologies is more and more filling with smart clothing. Increasing aesthetic by use of smart clothing technology is vital when designing a dance costume. Available works on the question are dedicated to either designing and wearing of dance costumes or smart clothing itself with no regard to dance costumes. The aim of the current study is to systemise smart clothing technologies those might be used for dance costumes to provide the ability to change visual characteristics by using mobile app. Statistical analysis was applied to investigate the specifics of the smart clothing range and its interactions with mobile apps. The method of prototyping was used to assess the necessity of providing the smart clothing item with specific mobile app. A dance costume was designed on basis of light emitting diode technology. The assessment was done by members of dance teams. It was determined that mobile app would be more suitable way to manage light modes of costumes due to the fact that smartphones are usually carried around and remote controls are not. The app will provide more competitiveness of the clothing as well as insure comfort of a dancer.
Method of historical pattern analyzing
Authors: Zhang S C , Kuzmichev V E
Published: February 2021

Simulation of historical costume requires digitalization of pattern block. This research developed the method of reconstruction of historical men’s coat by parameterized pattern blocks and CAD. The method includes three steps. Firstly, to collect the information about historical body measurements, drafting systems of patterns, clothing construction, methods of production and shaping, etc. Second step is the digitalization of patterns. Thirdly, to extract the body measurements and the ease allowance from pattern blocks. Fourthly, the calculation of shaping techniques values. Finally step includes the virtual reconstruction of costume. The database containing the historical pattern blocks, the manuals of drafting methods, the parameters of pattern, the body measurements, the eases of 47 historical men’s coat, and the values of shaping methods was established. Data base allows to calculate hided body measurements from patterns and to reconstruct of historical men’s coat with high accuracy in virtual reality.
Embedded system environment self-awareness using LIDAR technologies for robotics applications
Authors: Bogdanov S G , Chikurtev D S , Spasova N R
Published: February 2021

LIDAR technology is a major part of autonomous robots. That technology provides the necessary data for autonomous navigation, localization, surface scanning and obstacle detection. This paper presents a modular embedded system architecture, which is a part of a self-sufficient AI. The LIDAR software module of the proposed system is described. That module will provide 2D information about the surrounding environment. It is developed like a loadable module with options for self-compiling in the system. This research is the first step of self-awareness embedded system. In addition, we illustrate the application of the module in localization and navigation of mobile robots. The results achieved show that the developed software module is applicable for robotics localization and navigation.
Research on N-grams feature selection methods for text classification
Authors: Georgieva-Trifonova Tsvetanka , Duraku Mahmut
Published: February 2021

Text classification requires previously extraction of features describing the text documents in the collection. Usually these features are based on the occurrence frequency of words, N-grams of words in documents, i.e. the vector space model for document representation is built. Feature selection allows to reduce redundancy in high-dimensional representation of text data, which can significantly improve text classification performance. In the present paper, research on feature selection methods is performed in terms of the accuracy and F-measure of text classification with different number of selected attributes (N-grams of words) for different classifiers and different datasets. The obtained results can be used to apply further pre-processing steps, which include modifying the vector space model in order to achieve its improvement in terms of the text classification.
A Computer-Based Simulation Showing Balance of the Population of Predator and Prey and the Effects of Human Intervention
Authors: Kumar Ankit , Jani Kunal , Khatri Divyansh , Patel Hrishitva , Sharma Aditya Kumar , Sahu Nabin Kumar
Published: February 2021

In this paper, a computer-based simulation of the predator-prey model has been proposed. The prey is a source of food for the predator, which is necessary for the prey’s survival. Various models, such as the Lotka-Volterra model and the cellular automata model, have been used to simulate predator and prey movement in a population. These methods have been discussed briefly. The limitations of both these methods have been highlighted. After discussing the limitations of both these methods, a novel computer-based simulation has been proposed to address the previous models’ limitations. Since this model takes into account a more realistic movement of predator and prey, it has been used to study the harmful effects of human intervention on the environment. In this simulation, the birth of predators and prey by mating, the death of predators and prey due to starvation, and the death of prey due to attacks from predators are taken into consideration. In the first case, there is no human intervention. In the next two cases, human intervention is taken into consideration. In one case, the proportion of predators in the population increases, and in the other case, the prey population increases. A comparison has been made between all three cases, and a study has been done showing how human intervention affects the population of predators and prey over a long time.
Graphical simulation of functions
Authors: Shivacheva G I , Yankov K B
Published: February 2021

In scientific research, it is normal practice to arrive at a description of the analyzed process with the function of one independent variable and the participation of several parameters, which are also assumed to be independent quantities, but in the study they have relatively constant values. These parameters are usually used to adjust the process, ie when choosing their specific values, the process meets the requirements of the researcher for optimality according to pre-selected criteria. The present work aims to develop a graphical user interface for managing parameters involved in an analytically presented function. The possibilities of the Korelia program for function research are considered. The function is entered as a string. After the lexical and syntactic analysis, a table of identifiers and an reverse polish notation of the function are formed. By modifying the values of the parameters of the function, the user tracks the changes in its graph. In this way, the role of each of them can be assessed.
Clustering of Red/White Wine and Allergen/Non-Allergen Data Sets by Using Descriptor Fingerprints
Authors: Stoyanov B P , Dimitrov I E , Doytchinova I A , Bangov I P
Published: February 2021

An application of the descriptor fingerprints in relation to a clustering procedure of red and white wines and food allergen/non-allergens has been studied. The clustering method is based on a procedure using the Tanimoto similarity index. Different threshold values have been employed in order a best set of clusters to be obtained. It was shown that this procedure produces quite good discrimination between the red and white wines, but any correlation with the human sensation tastes (represented by a scale from 1 to 10) is more difficult to be obtained. The results from 4212 food allergens/non-allergens show a much better discrimination of those two groups starting from threshold value=0.5.
Predicting the day of storage of dairy products by data combination
Authors: Vasilev M D , Shivacheva G I , Krastev K I
Published: February 2021

Existing methods for tracking changes in the quality of dairy products are characterized by difficulty, time consuming, a large number of calculation procedures and resources, which makes them unsuitable for “on-line” monitoring. In the present work, feature vectors containing color components, spectral indices and physicochemical parameters of the products are used. Methods for selection of informative features based on consistently improving assessments have been applied. Models by principal components and latent variables are derived. It has been proven that the models are adequate and can be used to predict the day of storage of yellow cheese and white brined cheese. The advantage of the proposed data processing procedures, comparing them with those reported in the available literature, is that they require less computational resources, which makes them suitable for use in “on-line” monitoring of the condition of dairy products during storage.
Numerical calculation of multidimensional integrals depended on input information about the function in mathematical modelling of technical and economic processes
Authors: Nechuiviter O P , Iarmosh O V , Kovalchuk K H
Published: February 2021

The object of study is a numerical integration of the functions of several variables using new information operators. The cubature formulas of the approximate calculation of double and triple integrals for different information operators are presented. Information about function is given not only by the values of a function in nodes, but also as a set of traces of a function on planes or as a set of traces of a function on lines. Attention is paid to the application of such approximate calculation of integrals in various fields of science.
Adapting a method for tracking the movement of the camera in the visualization of augmented reality
Authors: Galabov Miroslav , Pastarmov Yulian
Published: February 2021

This paper presents an adapted method for tracking camera motion in the visualization of augmented reality. A tracking algorithm based on significant points and descriptors without the use of optical flow is described. The tracking module is written in C++. Experiments have been carried out of the precision of the system using the camera motion-tracking module created.
Model of a personal guide for museum exhibitions
Authors: Trankov Miroslav , Hadzhikolev Emil , Hadzhikoleva Stanka
Published: February 2021

Cultural and historical institutions in Bulgaria are often underfunded and do not provide sufficiently attractive digital services. All museums develop and maintain scientific passports of cultural artefacts, which contain photographs and specific characteristics of the exhibits. In some cases, they store digitized information in accordance with established standards for the digitization of cultural heritage, such as Dublin Core, SPECTRUM, LIDO, CCO, etc. The widespread use of smartphones provides museums with the opportunity to expand the museum service by dynamically and automatically delivering contextual information about the artifacts. The article presents an approach to creating a personal guide for museum exhibitions, which uses beacon technology to automate the process of providing contextual information about museum exhibits to its visitors.
Criteria for selection of statistical data processing software
Authors: Yordanova Lina , Kiryakova Gabriela , Veleva Petya , Angelova Nadezhda , Yordanova Antoaneta
Published: February 2021

There are many statistical software packages that automate the activities related to statistical data processing and visualization of results. Often the choice of a statistical package by consumers is a difficult process and it is necessary to compare different products in order to highlight the most appropriate. The selection of one or another statistical package should be based on clear criteria and be made in accordance with the objectives set by the researchers. In the present work, the criteria for comparing statistical packages are systematized into the three groups and applied to four packages.
Explore the possibilities for objective assessment of some beer quality indicators
Authors: Gabrova R , Danev A , Ganchovska V , Andreeva H
Published: February 2021

The aim of this research is to develop an appropriate experimental setting and to explore the possibilities for objective automatic and express assessment of some appearance indicators of beer quality using computer vision techniques. The goal of the research will be achieved by developing a computer vision system, including a hardware module for obtaining primary information and a software module for processing primary information and extracting the desired characteristics through algorithms based on adapted image processing methods.
Predicting soil moisture based on the color of the leaves using data mining and machine learning techniques
Authors: Atanasov S S
Published: February 2021

This research article’s aim is by using data mining and finding a suitable machine learning algorithm (MLA) to predict soil moisture, therefore the need for watering. Prediction is based on a training data set (including color RGB values taken from the leaves and values for soil moisture and soil temperature). A classifier is trained first, on its base a model is created and stored. Finally, with a different test data set, the efficiency of the selected model is checked. The object of study is the color of leaves of indeterminate greenhouse tomato plants of the Panekra variety. According to preliminary assumptions, the most informative about the need for watering are the young leaves (on top of the plant). Among the wide variety of data mining tools, we chose Weka Workbench. The last task of this study is to compare received with the methods of machine learning model and the model obtained in a previous study. For greater completeness of this research, the training of the classifier has been performed both with the whole training data set and with smaller data sets filtered by certain criteria (young/old leaves, etc.). The ultimate goal is water-saving and optimizing watering and water using. The resulting model is efficient and predicts soil moisture based on the color of the young leaves with 0-5% error, and by 8-12%, based on the color of the old ones, before watering, taking into account the influence of soil temperature into the model.
Analysis of energy efficiency of an industrial system
Authors: Ivanov Krasimir , Georgieva Nely , Tasheva Stanislava , Gandova Vanya
Published: February 2021

Survey energy efficiency of an industrial system was done. On the base energy audit, the consumption of energy and water was made analyse. On the following audit, there were made choices of energy saving measures, which would lead to proving and economy of energy in the industrial system and condition to work. The ultimate and primary energy savings for the industrial system, as well as CO2 emissions, were determined.
Influence of the price of electricity for the industry on the consumption in the economic sector in Bulgaria
Authors: Yotov Kostadin , Hadzhikolev Emil , Hadzhikoleva Stanka
Published: February 2021

Forecasting electricity consumption is extremely important for the planning and management of a country’s electricity system. It is an important factor for the effective planning of the production facilities operation, the future exports or imports, the behavior and direction of energy flows both in the country and in the connected international networks. Electricity consumption depends on many macroeconomic and demographic indicators, social parameters, climate conditions, etc. Their study and prediction with standard mathematical methods is a complex task. The article presents a study conducted using one of the most popular artificial intelligence techniques, namely – neural networks. Two models of neural networks have been created. One models the changes in the price of electricity, and the second – the dynamics of electricity consumption depending on its price.
Characteristics and rheological properties of ammonium oxalate extracted rosehip pectin
Authors: Taneva I , Petkova N , Krystyjan M
Published: February 2021

Rosehip fruits are an abundant source of bioactive compounds with enormous application in food technology, because of its nutritional and healthy properties. However, isolation and characterization of rosehip pectin remained challenges, because its properties depend on extraction procedure. Therefore, this study aims to evaluate the characteristics of ammonium oxalate-extracted rosehip pectin and its rheological behavior. Dried rosehip fruits (cultivar Plovdiv 1) were used for alcohol-insoluble solids (AIS) preparation. Rosehip pectin was extracted from AIS using 0.5% aqueous ammonium oxalate. The obtained polysaccharide was characterized with a degree of esterification 68%, degree of acetylation 1.0%, anhydrouronic acid content 87% and yield 13%. FTIR spectrum confirmed the pectin structure with typical bands, especially in finger print region showing the presence of α-(1→4)-bond between the galacturonic acid units. To the best of our knowledge, some physicochemical properties of rosehip pectin were evaluated for the first time. The rheological studies showed the non-Newtonian, shear-thinning and weak thixotropic behavior. The rosehip pectin demonstrated good swelling properties (22 ml/g), higher water holding capacity (6.04 g water/g sample), than oil-holding capacity (2.44 g oil/g sample). The obtained results highlighted that rosehips are rich in pectin with valuable rheological properties, revealing their potential use in food technology.
Influence of conventional and organic agriculture practices on the total phenols and antioxidant potential of Florina apple fruits
Authors: Petkova N Tr , Kuzmanova S , Bileva T , Valcheva Ek , Dobrevska G , Grozeva N , Popov V
Published: February 2021

The aim of the current study was to evaluate the influence of conventional and organic growing conditions on the total phenolic content, the total flavonoids content, the total monomeric anthocyanins content and the antioxidant potential in the apple fruits of Florina variety. The samples were grown and collected from the experimental fields, around Plovdiv and the village of Brestnik. The total phenolic content, the total flavonoids, the total monomeric anthocyanins content were determined. The antioxidant potential was evaluated by four different assays. The apple fruits grown under organic conditions contained higher total phenolics and they showed stronger antioxidant activity than fruits from the conventional conditions. The total phenolic content was from 3 to 5 mg gallic acid equivalent/g dry weight. The total flavonoids were below 1 mg quercetin equivalents/g dw. In the organically grown fruits, the average values for antioxidant activity varied from 30 to 100 mM Trolox® equivalent/g dw. The total monomeric anthocyanins in the organically grown apples their levels were the highest (67 mg cyn-3-glc/100 g dw). There was a positive, high correlation between antioxidant methods and the total phenolic content and total monomeric anthocyanins. These results indicated that organically grown apples accumulated higher levels of antioxidants and bioactive compounds, in comparison to conventionally grown apples.
Determination of viscosity in O/W emulsions and correlation with prime oil phase
Authors: Tasheva S Tz , Gandova V D , Petrova I G , Dobreva K Z
Published: February 2021

Oil-in-water (O/W) emulsions with 10%, 20%, 30% and 40% oil were prepared using soybean protein isolate (SI) 1, 2 and 3% as stabilizer. Viscosity of emulsions was determined. Microscope observation of all emulsions immediately after preparation was performed. Correlation among viscosity, emulsion droplet size and percents of oil phase were found. Emulsions prepared with high percent oil exhibit smaller average droplet size and greater stability.