bluuebunny/crossref_metadata_2025 huggingface dataset:
Control mode and topology of hydrogen fuel cell DC/DC converter
Authors: Li Zhihua , Chen Jing , Xiao Chun , Chen Zhenglong
Published: October 2020

The decrease in hydrogen fuel cell durability is due to the excessive input current ripple of the DC/DC converter. An improved DC/DC converter is used to reduce the input current ripple in order to solve this problem. This DC/DC converter is modified on the basis of a staggered BOOST DC/DC converter, the input current ripple of the DC/DC converter is effectively reduced. In this paper, the principle of current ripple generation is analyzed, the operation mechanism of the DC/DC converter is analyzed, the corresponding control mode is selected. The DC/DC converter designed is simulated. The result is shown as below: the input current ripple coefficient of DC/DC Converter is controlled to less than 1%, the smoothness of the output current of hydrogen fuel combustion battery is guaranteed.
Research on iris location based on improved particle swarm algorithm and sub-regional noise reduction
Authors: Wenyu Zhu
Published: October 2020

Iris localization is the basis of iris recognition, iris medical diagnosis and other technical fields. In view of image of Asian iris, according to the characteristics of the human eye pupil, the combination method of image back-complement enhancement and improved particle swarm optimization is firstly adopted to fit and locate the inner circle of iris. Then, combined with the characteristics of the outer iris boundary, the outer iris circle is located by using the method of sub-regional noise reduction and improved particle swarm optimization. Meanwhile, coordinate transformation approach is introduced for normalization of image. Finally, the feasibility of the method is verified by using iris library of Chinese Academy of Sciences and the self-built iris library sample. This study successfully overcomes the interference of the spot in library and can efficiently complete the segmentation of the iris region.
Simulation design and optimization of production line of a cross axis machining based on Plant Simulation
Authors: Changhong Yu , Songqing Cen , Silin Luo
Published: October 2020

In order to study the operation process and results of an actual intelligent production line, Plant Simulation was used to simulate the production line of a cross shaft. First of all, the basic layout is modeled, 3D model is used, and the actual machine model is imported or designed to make the effect more realistic. This study analyzed the production process, created orders according to customer requirements, used Simtalk language to complete the simulation logic of the model, and displayed the simulation data in the form of charts after the operation, so as to make the results more intuitive. Finally, the results are analyzed and optimized.
Research on Design and Simulation of Compound Voltage Quality Regulator
Authors: Zhang Guomin , Zhen Xiaoya , Man Hongwei
Published: October 2020

A voltage regulator based on cascaded multi-level structure is proposed. Based on the analysis of its working principle, the voltage quality problems (voltage sag, swell, voltage harmonics, Fluctuation, flicker) in the power quality appearing in the distribution network, the main circuit topology, control methods and compensation strategies are proposed. The regulator can compensate for various voltage quality problems. To ensure that the voltage quality is within the rated range, a simulation model of a cascaded multi-level composite voltage regulator is established in the simulation software, and it is verified that the design scheme proposed in this paper can solve various voltage quality problems in the distribution network.
Research on Mechanical Design Based on Rationalization of Mechanical Manufacturing Process
Authors: Yi He
Published: October 2020

The advancement of science and technology in China has promoted the economic take-off. As an important part of the secondary industry, machining and manufacturing play an irreplaceable and important role, which is widely used in major fields. Many industries are moving towards the production of fully automobile machinery. The use of advanced automobile mechanical manufacturing technology has greatly improved the productivity, reduced manpower input and costs while ensuring product quality, and achieved the goal of maximizing economic benefits.
Research on Time-Varying Mesh Stiffness of Double Involute Gears
Authors: Yin Zhaoming , Fan Zhimin , Jiang Feng
Published: October 2020

The tooth of double involute gear (DIG) is considered as a cantilever beam on the tooth root circle, considering the real tooth profile of DIG, an improved energy method is used to solve the time-varying mesh stiffness. The influence of tooth waist order parameters and the difference of time-varying mesh stiffness between DIG and common involute gear(CIG) are studied. The results show that the time-varying mesh stiffness of the single tooth pair is less than that of CIG with the same parameters when the contact line passing through the tooth waist grading position, and the comprehensive time-varying mesh stiffness of DIG is less than that of CIG. The tooth waist order parameters will affect the time-varying mesh stiffness of DIG, and compared with the tooth waist altitude coefficient (l*), the tooth waist tangential modification coefficient (y*) has little effect on the time-varying mesh stiffness.
Analysis and Research on the Impact of Bullet Head Eccentricity on Air Resistance
Authors: Lin Lizong , Ju Ran
Published: October 2020

Through numerical simulation, the transverse resistance of the head eccentric bullet at 0.29 Ma, 0.58 Ma, 0.97 Ma and the eccentricity angle of 0° ∼5° in the air was studied. When the bullet head deflects and flies at a certain speed, the tip of the bullet produces agitation to the air. This paper tries to find out the angle of minimum resistance by using the simulation software ANSYS when the eccentricity angle of the bullet head is between 0° and 5° degrees, and optimize the shape of the existing bullet. In this paper, three kinds of velocity are simulated. The simulation results show that the resistance of the head eccentric bullet in flight can become smaller. There is always a corresponding head eccentric angle at different speeds to minimize the flight resistance. As a result, the bullet can fly faster and farther.
Study on the test method of rapid change of load current of intelligent electricity meters
Authors: Chen Zhiru , Du Yan , Zhang Zhi , Dai Yanjie
Published: October 2020

With the continuous changes of the working environment of the electric energy meter, the dynamic detection method of the electric energy meter becomes more and more important. Therefore, in recent years, the IEC 62052-11 Standards Committee has proposed to add a rapid change test of electric energy meter load current. This article proposes an effective dynamic test method according to the requirements of this regulation standard, builds an electric energy meter dynamic error test platform and develops a software test system. An anti-submarine mechanism is proposed for the electric energy measurement algorithm of the smart meter, and the load current rapid change test of various electric energy meters from different manufacturers at home and abroad is tested, and the correctness of this test method is verified.
System Resilience construction Model of Human-automation Manufacturing Process
Authors: Chen Ke , Song Li
Published: October 2020

Despite increasing automation levels and digital solutions, manufacturing process safety still very much rely on the inescapable contribution of the human factor. The changing relationship between man and automation system together with the increased complexity result in high risks for process safety. From time perspective, the resilience of a manufacturing system shows a curve divided into dimensions: adaptability, recovery and innovation. Perceptual stance, contextual integration and decision making and doing are made up of system resilience elements. As a socio-technical system, a human-automation manufacturing system may strengthen resilience by considering both technical and organizational sides.It is an effective approach to construct manufacturing system resilience by assigning the functions according to the task, the operator, and the situation considering the system dynamics.
A sequence-based visual place recognition method for aerial mobile robots
Authors: Yang Minzhou , Mao Jun , He Xiaofeng , Zhang Lilian , Hu Xiaoping
Published: October 2020

Recent developments in sequence-based visual place recognition (VPR) have shown robust localization capability on ground vehicles; however, deploying existing sequence-based VPR techniques on aerial mobile robots is still challenging, as topologically ordered database is not available for aerial agents. In this paper, we develop a new sequence-based VPR algorithm, which is applicable to aerial mobile robots. The proposed method models the agent’s position as a probability function conditioned on all the visual observations and accumulates the position belief as the observation increases, which helps to filter out the inconsistent false recognitions. To testify the effectiveness of the proposed method, we have conducted series of experiments under different visual environments. The experimental results show that, by using a remote sensing image as reference and onboard downward-looking camera images as observations, the proposed method can robustly estimate the position of the agent and have a localization rate 30% higher than the single-image-based VPR algorithm.
Optimal design of concrete automatic distribution system for digital manufacturing
Authors: Yu Yongpeng , Ji Shuai , Chen Jiwen , Wu Chong
Published: October 2020

Concrete distribution system is an important production equipment to realize the development of prefabricated buildings. In order to realize the development of building industrialization and residential industrialization, considering the problems of intelligent and low automation of concrete distribution system, by perfecting the structural design of automatic distribution system, it is oriented towards digitalization. Manufacture, analyze and select the control of the opening of the distribution valve and the parameters of the distribution shaft, and put forward measures to optimize the overall mechanical structure of the distribution hopper of the distribution machine; establish the relationship model of the hopper moving speed of the concrete distribution machine, the speed of the spiral distribution shaft and the thickness of the distribution, to complete the optimal design of the motion parameters of the concrete distribution system. Based on the finite element analysis of the supporting beams, the feasibility and effectiveness of the overall optimal design of the concrete automatic distribution system were verified.
Research on Automatic Cleaning Equipment with High Pressure Water Jet for Optical Pipelines
Authors: Yang Biying , Lian Kenan , Zhao Yunwu , Zhu Jianping , Guo Ang
Published: October 2020

In order to solve the problems of high labor intensity, low efficiency, and unstable cleaning quality when cleaning optical pipelines with traditional manual high-pressure spray, automatic cleaning equipment with high pressure water jet for optical pipelines is designed. The working principle and the design points are introduced. The movement rule of the nozzle under self-propelled drive is analyzed by ANSYS, the results show that the self-propelled drive cannot meet the cleaning speed requirements. Therefore, the wire rope driving method is proposed to realize the control of the nozzle speed. Subsequently, the speed of the simulated water jet is analyzed by the STARCCM, it is inferred that the water jet is still in the basic section at the maximum target distance of the pipeline, which can be used for cleaning. For verifying the cleaning effect, the prototype is applied to the cleaning of the actual optical pipelines. The verification results show that the cleaning equipment can meet the requirements of 100 / class clean, and the efficiency is increased by 70% compared with the traditional manual high-pressure spray.
The Evaluation and Research of white light interference profiler about the measurement uncertainty
Authors: Hu Chang’an , Tang Yan , Sun Haifeng , Liu Lei , Hu Song
Published: October 2020

The optical resolution of the white light interferometer characterized by higher sensitively and accurately with 580nm wavelength approximately is 5nm. However, as a new non-contact measurement equipment, the white light interferometer has certain measurement errors. In this paper, we propose a novel method that the accuracy of the white light interference profiler is evaluated by measuring the nano grating standard structure. The standard step height and pitch sample were used in the measurement process, and the morphological characteristics of the sample were obtained by Fourier transform, phase modulation and phase splicing of the sampled data. The experimental results show that the horizontal and vertical extension uncertainty of the white light interference profiler is 174nm and 8.07nm, respectively.
A Power Optimization Control Method Based on IMC for 3D Printer
Authors: Xie Ruidong , Yang Haichuan , Yi Yingmin
Published: October 2020

Aiming at the effect of selective laser sintering technology used in 3D printing, the recursive least squares method was applied to fitting a control system model for quantification the relationship between laser power and corresponding temperature in this paper. The internal model control method is considered based on the establishing model. The controller is put into the actual 3D printing power control system for controlling the laser power. In the experiment, both internal model controller and the PID controller for the 3D printer are researched and deployed for comparing the their effects in the paper. The experimental result illustrates that the IMC based on the recursive least squares method is of effectiveness.
Research and test of key components of the squirrel-cage bullet shell counter
Authors: Yaxin ZHANG , Hua XU , Renggui LIU , Wanmin LI
Published: October 2020

In order to solve the problem of counting when the bullet shells is recovered, a kind of squirrel-cage bullet shells counters is designed. Through theoretical analysis and test, The angle of the bullet slot of the squirrel cage shell counter is 31.3 ° and the rotation speed of the cartridge mechanism is 10 R / min. The squirrel cage shell counter has the advantages of simple structure, few components, 3D printing technology, greatly reducing the weight and power consumption. The whole machine test results show that: The counting efficiency of the slot type bullet shell counter is 87.4 pieces / minute, and the counting accuracy is 99.8%. The counting efficiency and precision of the slot type bullet shell counter can meet the design requirements of the army. This research not only provides a practical shell counting tool for the military, but also provides a reference for the innovation, research and optimization design of other similar mechanical equipment.
Static characteristics and influencing factors analysis of azimuth axis of a radar antenna pedestal
Authors: Guang WEN , Ming CHENG , Xianchun TANG , Xinhui JIANG , Xuerong ZHANG
Published: October 2020

Azimuth axis is an important part of radar antenna support. Static characteristics were analyzed with the help of finite element software. And the stress and deformation distribution of the structure under the normal working load were obtained, and the influence of the size parameters of the azimuth axis structure on its static characteristics was also investigated. Through the analysis, it is found that the maximum stress value of the azimuth axis under the working load is less than the allowable stress of the material, and the strength meets the use requirements. With the increase of size parameter l3
and d11
, the maximum stress of the shaft decreases gradually, and increases with the increase of size parameter d32
. The analysis results provide data reference for further optimization of the azimuth axis.
Mapping the field of Building Information Modeling(BIM) based on bibliometric analysis
Authors: Huang Yunping , Yan Jinjiang , Chen Lingling
Published: October 2020

Building information modeling(BIM) makes great contributions to empowering the construction industry and it has been adopted widely in many fields. To capture existing circumstance and future trend of BIM in the perspective of bibliometric analysis, we analyse 1247 papers related to BIM publications which are collected from the Web of Science database with time span defined as “all years”. Results concerning the publications and its citation structure, the network of co-authorship in countries/region and institutes, the network of co-citation in cited references, and keywords co-occurrence are presented in this paper, and VOSviewer software is used as a visualising analysis tool. This paper not only summarizes the research progress of BIM but also provides a useful method for the future evaluation of construction field.
Application of green energy saving technology in construction engineering
Authors: Wu Wei
Published: October 2020

This paper introduces the basic concept of green energy-saving technology in architectural design. The necessity of applying green energy-saving technology in building engineering construction is also described. The application of green energy-saving technology in roof doors and windows, wall insulation, circulating water pump heating, clean energy and heat pump application are presented. All these works broadens the way forward of building construction and lays a good foundation for the development of construction industry.
Influence of transmission tower load under extreme conditions during operation period on the stability of landslide and tower foundation
Authors: Yingbo Zhou , Hang Chen , Qiupeng Zhou , Zhiqiang Duan , Xiaojing Gao
Published: October 2020

Taking Yanzi landslide and 500 kV transmission tower foundations on the landslide as the research object, this paper presents a study of the influence of transmission tower on the stability of landslide and tower foundation under extreme conditions during operation period. Firstly, the ultimate loads of transmission tower foundation under different operating conditions are determined. Secondly, based on the limit load of transmission tower, the overall and local stability of Yanzi landslide is analyzed. Finally, the disturbance of tower foundation load state on soil around the tower foundation and the change of tower foundation displacement are studied. The results show that, with the increase of wind speed, the tower foundation load In addition, under the action of wind load, the soil around the adjacent tower foundation basically does not affect each other, the maximum displacement of tower foundation does not exceed 0.5 mm, and the maximum inclination rate of tower foundation meets the requirements of cod.
Marine hazards from 2000 to 2016 in Zhejiang province of the subtropical region, South China
Authors: Guo Jiamei , Heng Fuxin , Huang Zhilei , Qi Shanzhong
Published: October 2020

Coastal and offshore regions are regarded as the key zones exposed to marine disasters. Zhejiang province, located on the verge of the East China Sea, is one of the provinces mostly affected by marine disasters that have brought serious economic losses and casualties. The data of marine disasters in Zhejiang province, which occurred during the period from 2000 to 2016, were selected and analyzed. The results indicate that (1) storm surge, wave, and red tide are the main kinds of marine hazards in the coastal region of Zhejiang province. (2) a total of 1,099 marine disasters occurred in the coastal region of Zhejiang province during 2000—2016, and resulted in about 275 deaths or missing with 18.544 billion yuan of direct economic losses. In addition, marine disasters are mainly distributed in Zhoushan City, Ningbo City, Taizhou City, and Wenzhou City of Zhejiang province.
Near real-time detecting of atmospheric water vapor content based on BeiDou Navigation Satellite System
Authors: Guo Qiuying , Hou Jianhui , Chen Shihai , Sun Yingjun
Published: October 2020

With the improvement of Beidou navigation satellite system (BDS), real-time monitoring of atmospheric water vapor content based on BDS has become a research hotspot. BDS and GPS observation data of seven MGEX CORS stations were processed using GAMIT10.71 software and the atmospheric precipitable water vapor (PWV) was estimated. The PWV/BDS using Beidou final precise ephemeris and ultra-rapid precise ephemeris was respectively compared with PWV/GPS using IGS final precise ephemeris. The experiment results showed that the PWV/BDS is in good agreement with the PWV/GPS. The standard deviation (Std) of the PWV/BDS based on Beidou final precise ephemeris and ultra-rapid precise ephemeris are respectively 2.91mm and 3.97mm. And the RMSE of the PWV/BDS based on Beidou final precise ephemeris and ultra-rapid precise ephemeris are respectively 3.97mm and 3.85mm with the PWV/GPS as the reference value.
Research on Computer Network Teaching Reform Based on Simulation Software
Authors: Wang Jiong , Zhang Hua , Wu Zhengyuan , Xu Ge
Published: October 2020

This paper first analyzes the concept and development status of computer network technology, then expounds the problems existing in computer network practice teaching, and finally makes an in-depth analysis on how to formulate strategies to solve the problems existing in computer network practice teaching, including the detailed discussion and planning on the reform of course examination methods, the improvement of course setting and the study of software and hardware. Based on the current situation of computer network development in China, the practical teaching of computer network is continuously improved, which makes this course carry out smoothly in teaching.
Students depend on the Pythagorean theorem: Analysis by the three parallel design of abstraction thinking problem
Authors: Alghadari F , Noor N A
Published: October 2020

Based on students’ geometry knowledge, there are contrast and less relevant skills goals being prepared for the students. Students are more dominant in learning how to apply procedural knowledge so there is a need for students to use the Pythagorean theorem when facing a triangle properties problem. Therefore, this case study aims to analyze how students’ conceptual knowledge depends on the Pythagorean theorem. The analysis uses a cognitive diagnostic assessment framework through the three parallel design of abstraction problem. This study was conducted for students at the senior high school. The findings are the Pythagorean theorem as a result of thinking abstraction at least two of the three design problem formations, including for the effect of claims and metacognitive knowledge them. There is a disconnected conceptual system between the products of thought and the claims elicited so that abstraction is not optimal. Development for in-depth understanding of conceptual experience is needed in the instructional intervention so that more adequate reasoning.
Analysis of mathematical thinking skills in multiple intelligence perspectives of primary school students
Authors: Murni S , Ruqoyyah S , Fasha L H
Published: October 2020

This research is motivated by thinking skills and awareness of the importance of mathematics needs to be taught and trained to students from an early age because in daily life many things are related to thinking skills and awareness of the importance of mathematics in everyday life. The purpose of this study is to analyze mathematical thinking skills from the perspective of multiple intelligences of elementary school students. This research uses a qualitative approach and uses descriptive qualitative methods. The population in this study was Grade V Elementary School Students in Cimahi City, while the sample consisted of 20 students. The instrument used consisted of multiple intelligences tests in the form of a questionnaire logical-mathematical, intrapersonal, and interpersonal logic intelligence. The results showed that the intelligence of logical-mathematical and intrapersonal based on multiple intelligences of elementary school students in Cimahi in 2020 each was in the medium category. While interpersonal intelligence is in between medium and low categories.
Mathematical representation ability through geogebra-assisted project-based learning models
Authors: Septian A , Darhim  , Prabawanto S
Published: October 2020

The purpose of this study is to analyse the achievement, improvement, and achievement of indicators of mathematical representation ability between students who obtain a project-based learning model assisted by GeoGebra and students who get a project-based learning model. The research method used in this study is quasi-experimental with a non-equivalent comparison group design. The subjects in this study were students of the Department of Mathematics Education in the second semester of the academic year 2018-2019 at Universitas Suryakancana. The research instrument used was a mathematical representation ability test and the Group Embedded Numbers Test (GEFT). Analysis of the data used is the normality test, the Mann Whitney test, and the percentage of achievement indicators. As a result, the achievement and improvement of the mathematical representation ability of students who obtained a project-based learning model assisted by GeoGebra were better than students who obtained a project-based learning model, the achievement of the mathematical representation ability of students in the experimental group were good categorized, the control group was categorized sufficiently, the experimental group with field-independent and field-dependent cognitive style were categorized as good, the control group with field-independent and field-dependent cognitive styles was considered sufficient.
MGMP optimization in developing teacher professionalism in developing HOTS problems based on RME approach
Authors: Edwar  , Putri Ratu Ilma Indra , Zulkardi  , Darmowijoyo
Published: October 2020

The results from the Program International Student Assessment in 2018 placed Indonesia at number 74 out of 79 countries, It shows low student ability in Higher Order Thinking Skills (HOTS). One of Them is caused low competence of teachers in applying HOTS in the subject. Therefore, we need a method to improve teacher competency. One method used is to optimize training HOTS development in the Subject Teacher Forum or called MGMP using the Realistic Mathematics Education approach. This research includes preliminary, prototype, and field tests. This research is on high school mathematics teachers in East OKU Regency. Analysis of this research data using a walkthrough, documents, and tests. The results of this study prove the increase in teacher competence in generating valid HOTS questions. Valid is when all validators said HOTS problems that are generated both in content and construct, practical (questions used for student learning, easy to read, do not attract diverse interpretations, and can be given to all students). Also, research has the potential for student learning outcomes with an average value of 70.16 student abilities. This research also improvement of student learning activities, as seen from the results of the analysis of activities students that are 3,09.
Somatic, auditory, visualization, intellectually learning assisted by GeoGebra to improve student’s mathematical representation skills
Authors: Septian A , Suwarman R F , Monariska E , Sugiarni R
Published: October 2020

The purpose of this research was to determine the improvement of student’s mathematical representation skills and student’s attitudes towards learning using SAVI learning assisted by GeoGebra. This research is a quasi-experimental research with the object of research of students of SMP Negeri 3 Cianjur. Students in class VIII-5 will be the experimental class and students in class VIII-7 will be the control class. The method used in this study is quasi-experimental research methods with non-randomized control group pretest - post-test design. Data processing will be executed with the normality test, Mann Whitney test, and the percentage of achievement indicators. Based on the results of data processing and interpretation, it is shown that SAVI learning assisted by GeoGebra better than ordinary learning in improving student’s mathematical representation skills. Then the attitude of students towards SAVI learning assisted by GeoGebra is generally positive.
Project based learning design “trade in school cooperation” for seventh grade students of junior high school
Authors: Sari Elisa Mayang , Putri Ratu Ilma Indra , Meisinta Lipa , Sunaryati
Published: October 2020

The direct proportion and social arithmetic are difficult topics for students. The difficulty on the topic of direct proportion is that students make mistakes in adjusting the application of direct proportions. The difficulty of social arithmetic is a mistake in determining the conditions of profit, loss, or break even. Project-based learning is an innovation for teachers and can improve students’ thinking abilities. The characteristics of the project involve some topics. Teachers are expected to work together to create learning according to expectations by implementing a lesson study system. Project-based learning that takes a long time can be overcome by using Edmodo because they can do learning without space and time limits. This research aims to determine the role of the learning trajectory in project-based learning “trade in school cooperation”. This study uses a design research method of validation studies type in seventh grade students of junior high school in Palembang. The results are the role of project-based learning in resolving direct proportions and social arithmetic through learning trajectory such as students getting more training in problem-solving procedures, better understanding the relationship of numbers proportions, and to achieve understanding in decisions of profit, loss, and breakeven situations.
Multiplication and division of integers through cultural approaches of playing dakon
Authors: Widada W , Herawaty D , Pusvita Y , Anggreni D , Aripianti R , Panduwinata B
Published: October 2020

Playing dakon has become a culture in Bengkulu. Since I was in kindergarten, dakon has been a fun game. It has the character of sharing fruit in each dakon convex (or hole). It becomes the starting-point of learning multiplication and division. The purpose of this study was to determine students’ thought processes in understanding the principle of multiplication and the division of integers through the cultural approach to playing the dakon. To achieve the goal, achieved through qualitative-explorative research. The subjects of this study were elementary students in Bengkulu City who were selected based on assignments. It was selected from 30 students who were given assignments about multiplication and division of integers. Students are given instructions using worksheets. After students submit their assignments, they are analyzed to select 2 students who have the thought process in achieving the principle of division and multiplication appropriately. Subjects were interviewed in-depth by researchers. Data were analyzed based on the genetic decomposition of research subjects. The results of this study are the Subject-1 can use the dakon to show the multiplicative properties of positive integers. He demonstrated that 4x3 by inserting it into four small dakon curves and three dakon seeds each. She concluded that multiplication is a repeated sum. Subject-2 uses the dakon to find the concept of dividing two positive integers. Subject-2 shows that 12: 4 by taking dakon seeds from a large curvature containing twelve seeds. She concluded that the division is a repeat reduction. This research concludes that Subject-1 and Subject-2 can build an understanding of operations multiplication and division, including verbal communication, writing, and drawing based on real media from local culture, namely the dakon game.
The cognitive process of students in understanding the triangles in Geometry of Riemann through local content
Authors: Widada W , Herawaty D , Widiarti Y , Herawati  , Aisyah S , Tuzzahra R , Berlinda K
Published: October 2020

Learning geometry is one that students fear. They have difficulty understanding the concepts of geometry. Students experience problems with Lobachevsky’s axiom alignment, as well as Riemann’s axiom alignment. Therefore, we need learning that makes it easy for students to imagine these axioms more concrete, although geometry cannot always be carried in a concrete world. The purpose of this study is to describe students’ cognitive processes in understanding the properties of triangles in Riemann Geometry through local content. This is a part of development research. We conducted a needs analysis of the ability of students to understand new concepts in geometry. The subject of this research was chosen from students of mathematics education at one of the tertiary institutions in Bengkulu City, Indonesia. Subjects were interviewed in-depth through task-based interviews. His job is to solve the problem of the properties of triangles in Riemann Geometry. Interview data were analyzed through genetic decomposition analysis. The results of this study were subjects able to analyze the interrelationship between concepts, axioms, and basic properties of geometry through orange peel media. He can attribute and organize. The attributes are obtained from three segments that meet at the ends. Subjects can organize the elements of the triangle so that the nature of a large number of angles in the triangle is more than 180. The conclusions of this study are the subjects can achieve the cognitive process of analysis, and can arrange the correct population.
Analysis of student learning styles and geometry thinking skills: During the covid-19 pandemic
Authors: Hamidah  , Kusuma J W
Published: October 2020

In social restrictions due to the current pandemic, there is a change in the learning system and changing learning styles. So it has the potential to affect mathematical abilities, especially geometry thinking skills. The problems are: 1)how the learning styles tendencies of students during the pandemic, 2)how the students ‘geometric thinking abilities viewed from the level of geometry according to van Hiele, 3)how the students’ geometric thinking abilities viewed from their learning styles, and 4)are their association of student learning styles with the level of geometry ability according to van Hiele. This research conducted at the University of Bina Bangsa in mathematics education, totaling 38 students. The method in this research is mixed methods. For quantitative data were analyzed using chi-square test and contingency test, while qualitative data were analyzed using flow models. The study found that during the covid-19 pandemic, the students tend to use auditory learning style and it is known that there is an association between student learning style and geometric ability level according to Van Hiele. Furthermore, it is known that the higher level of geometry ability of students, the higher indicators of ability to think geometry they have.
The abstraction ability about natural numbers through playing traditional music for elementary students
Authors: Herawaty D , Widada W , Ardy H , Furqany R , Suharto  , Anggoro A F Dwi
Published: October 2020

The ability of music has a positive impact on the balance of thinking. The purpose of this study is to determine whether the musical ability has a direct effect on the ability of abstraction of native numbers of elementary school students at a low level. This is survey research as an evaluation stage for the development of elementary thematic learning models in Kota Bengkulu, Indonesia. The research sample was 95 elementary school students in Kota Bengkulu. The instruments of this research were musical ability tests and abstraction ability test. Data were analyzed through the Lisrel 8.8 test. The results of this study is that musical ability has a direct positive effect on the ability of abstraction of native elementary students to a low level.
Designing PISA-like mathematics problem in covid-19 pandemic (PISAComat)
Authors: Nusantara D S , Zulkardi  , Putri R I I
Published: October 2020

A new policy demands PISA-like mathematics problems given to improve knowledge of literacy and numeracy as well as life skills in the Covid-19 pandemic. However, this didactic phenomenon has not been utilized as a context in learning. This research was design research with the type of development studies that aimed to produce PISAComat, which was valid, practical, and had potential effects on secondary school students’ mathematical literacy abilities by conducting walk-through, test, document review, and interview as data resources. From the result of expert reviews and one to one phase, the developed PISAComat has been valid. It is viewed from its compatibility with the PISA framework i.e., students are familiar with the current context, the content is indeed studied at the 9th grade, and the difficulty level of 5 in PISA. The language used is precise and does not contain a variety of meanings. The practicality can be seen from students who can understand and solve the problem given easily by involving students’ mathematical literacy. Also, the PISAComat had potential effects on mathematics literacy, such as reasoning and argumentation, to give perception and interpretation and to improve insights related to the education of life skills to face the Covid-19 pandemic.
Short preliminary analysis of student teachers’ mathematical knowledge of limit of a function
Authors: Oktaviyanthi R , Agus R N , Lestari I
Published: October 2020

The purpose of this short preliminary study is to investigate mathematics student teachers’ mathematical and didactical knowledge of the limit of a function, particularly in evaluating the value of the limit. This study modeled these investigations using the Anthropological Theory of Didactic, which describes mathematical activity in terms of the mathematical organizations or praxeologies and considers the teacher the director of the didactic process. In this study, the case study design was used, and four mathematics student teachers were examined within the context of evaluating the limit’s value. Mathematics student teachers’ result work, video recordings of the participants’ work in which they explained how to assess the value of limit and audio recordings of task-based interviews were used to gather data. Participants showed different ways of evaluating the value of the limit of a function and explained how they decided to answer based on their understanding.
Students’ errors in refractive thinking (the component of identifying problems) about spheres and distance in three-space
Authors: Yenti I N , Kusumah Y S , Dahlan J A , Fitri H
Published: October 2020

Identifying a problem is the fundamental component in the refractive thinking process. This activity is carried out after students read the given mathematical problem. Failure of students to identify problems will affect problem-solving strategies. Some strategies in solving problems can be found by identifying the information in the issues correctly. This study aims to reveal the errors of students in refractive thinking on the component identifying problems. The research subjects were 43 students who took the Multivariable Calculus course at one of the Islamic Higher Education Institutions in West Sumatra. The process of collecting data uses tests and questionnaires. This study found several errors in refractive thinking made by students when identifying problems, namely reading errors, language interpretation errors, comprehension errors, factual errors, and errors in visualizing mathematical graphics.
Collaboration and communication skills of pre-service mathematics teacher in designing project assignments
Authors: Zakiah N E , Fatimah A T , Sunaryo Y , Amam A
Published: October 2020

Collaboration and communication skills are an important skill in the 21st century. The study aims to acquire a description of collaboration and communication skills designing project assignments created by pre-service mathematics teachers. This study used a qualitative approach to observe the phenomenon of participants in making a project task. The participants were 43 pre-service mathematics teachers who took a course on teaching-learning strategies. Collaboration and communication skills are demonstrated by students when the process of planning products, making products, presenting, and evaluating products. The results obtained in this study are students can figure out their level of understanding of the results of the presentation he has done. This can help students to plan to make the next teaching material appropriately. Project assignments in groups can promote collaborative learning. This is very helpful to students who are weak to build confidence. These results suggest that project assignments not only test students’ understanding of a particular topic but also develop student collaboration and communication skills.
Analysis of multi-representation ability to solve algebra problem
Authors: Nirawati R , Darhim  , Fatimah S , Irma A
Published: October 2020

The phenomenon that occurs in everyday life, one of the mathematical topic that was difficult to understand by students is algebraic. In algebra, there are many symbols that make students difficult to understand and understand the concept of algebraic material. This research aims to describe the ability of multi-representation in solving algebraic problems based on students’ mathematical skills (high, moderate and low). Furthermore, the type of research used was descriptive research. The subject of research in this study is class VIII students SMP Negeri 13 Singkawang, odd semester of the school year 2017/2018 Overall the research results show the multi-representation that the student presented to the verbal representation of the average percentage of 54.46%, The average visual representation of the percentage was 59.09% while for symbol representation was obtained an average percentage of 48.92%. In this case, a highly capable subject presents a solution through various representations (verbal, visual and symbol) For medium-capable subjects, it was able to give an answer with symbolic and verbal representation and lacking in visual representation presentation. As for low-capability subjects are less able to present solutions in visual, verbal and symbolic representations.
VBA media development for microsoft excel against students’ mathematical problem solving
Authors: Rahayu G D S , Bernard M , Mulyono D , Rabbani S
Published: October 2020

Problem-solving is an ability that must be trained on students from the elementary school level. Through mathematical problem-solving students will have a good way of thinking, persistence, curiosity and confidence in dealing with new situations in everyday life. The method used in this study is a quasi-experimental design with a nonrandomized pretest-posttest control group design. The object of research is elementary school level students at the centre of learning activities in the City of Cimahi. Based on the results of the study, it was found that VBA-based media for Microsoft Excel influenced students’ mathematical problem-solving abilities. There are findings of the condition of students who find it challenging to solve coherent problems, because there is a rush and want praise when solving problems faster. The conclusion in this study is that VBA-based media for Microsoft Excel is better at improving students’ mathematical problem-solving abilities.
Mathematics Education in Digital Era: Utilizing Spatialized Instrumentation in Digital Learning Tools to Promote Conceptual Understanding
Authors: Putrawangsa S , Hasanah U
Published: October 2020

Although digital technology is widely used in education, there is still little explanation on how to design and utilized a digital learning tool to promote conceptual learning. To overcome this gap, we propose the idea of spatial instrumentation as a theoretical framework in designing (or developing) and implementing digital learning tools to promote conceptual understanding of mathematics learning through progressive mathematics. The reason, students can interact rich and meaningful and encourage them to use their basic understanding and intuition to support the learning process. Here, we outline theories that underlie ideas about spatial instrumentation, give examples of digital learning tools developed under these ideas, and show empirical illustrations of how students will interact with learning tools during the conceptualization process.
The effectiveness of online calculus 2 learning during the Covid-19 pandemic
Authors: Susilawati T , Darmawan I , Desiasni R
Published: October 2020

This study aims to analyze the effectiveness of online learning in calculus 2 during the Covid-19 pandemic. The study was conducted in a civil engineering study program at a private tertiary institution on Sumbawa Island. This research is a quasi-experimental research design model non-equivalent control group design. The number of subjects in this study was 71 people. Data analysis used a paired sample t-test analysis with the help of SPSS software. Based on the results of data analysis, online learning is not effective in calculus 2 subjects in the pandemic covid-19 period, there is a significant relationship between conventional learning and online learning and there is a significant difference between conventional learning and online learning. The average value of student learning outcomes is decreased when the online learning system is applied. From these results it can be concluded the online learning system in the 2nd calculus course during the Covid-19 pandemic has not been effective.
Process of algebra problem-solving in formal student
Authors: Widodo S A , Irfan M , Trisniawati T , Hidayat W , Perbowo K S , Noto M S , Prahmana R C I
Published: October 2020

The aim of this study is to describe the formal thinking process of students in solving algebraic problems. This study is descriptive qualitative, with two 7thgrade subjects taken using a purposive sampling technique. The main instrument in this study is the researchers own judgment, Test of Logical Operations instruments, and algebraic problem-solving tests. The data were collected from various sources using the think-aloud approach. Data were analysed, classified based on students’ cognitive development types (concrete, transitional, and formal) and transcribed into data presentation. The study found that, at the stages of understanding the problem and implementing the plan to solve the problem, the subjects successfully carried out the process of thinking assimilation and abstraction. On the other hand, at the stages of planning and re-examining answers, the subjects able to perform the assimilation process of thinking.