bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on a Text Topic Mining Algorithm Based on Big Data
Authors: Yang Zequn
Published: October 2020

Topic modeling has been widely used to mine topics from documents. However, a key disadvantage of topic modeling is that it requires large amounts of data (e.g. thousands of documents) to provide reliable statistics to generate coherent topics. However, in practice, many document collections do not have as many documents. Given a small number of documents, the topic generated by the classic topic model LDA is very poor. Even in the case of a large amount of data, unsupervised learning of the topic model will still produce unsatisfactory results. In recent years, knowledge-based topic models have been proposed which require human users to provide some prior domain knowledge to guide the model to generate better topics. Our research takes a completely different approach. We recommend learn like humans, i.e. retain the results learned in the past and use them to help future learning. When faced with a new task, we first mine some reliable (transcendental) knowledge from past learning/modeling results, and then use it to guide model inference to produce more coherent topics. This approach is possible because there is readily available big data on the Web. The algorithm mines two forms of knowledge: the chain must be (Meaning two words should be in the same topic) and cannot be linked (meaning two words should not be in the same topic). Two issues of automatic knowledge mining are discussed, namely the problem of erroneous knowledge and knowledge transferability. Use from the experimental results of the review documents of 100 product areas show that the method proposed in this paper has a significant improvement over the state-of-the-art baseline.
A model-based method for bearing fault detection using motor current
Authors: Wang Chen , Wang Min , Yang Bin , Song Kaiyu
Published: October 2020

Existing bearing fault diagnosis approaches utilize signal processing techniques in combination with vibration measurements. The common vibration measurement method, using accelerometer, has disadvantages such as position-constrains, high costs and external interferences. Meanwhile, the commonly used modelling methods of motor are not able to analyse both mechanic and electromagnetism simultaneously. For detecting the fault-related frequencies in motor current, a mathematical model is developed in this paper based on modified winding function approach (MWFA). The simulation results show that the fault-related characteristic frequencies can be exactly found in the spectrum results of motor current. The proposed method is proven to be feasible.
Genetic algorithm to improve Back Propagation Neural Network ship track prediction
Authors: Chen Xingqiang , Meng Xin , Zhao Yue
Published: October 2020

This paper studies a method that uses genetic algorithm to simultaneously optimize the number and weights of Back Propagation (BP) neural network neurons to predict the ship’s trajectory, so as to accurately predict the ship’s trajectory. The trajectory of the ship can be predicted by the neural network, but the selection of the setting parameters of the neural network requires rich experience and a large amount of attempts. In this study, the genetic algorithm (GA) is used to optimize the structure and weights of the neural network at the same time, avoiding the manual setting of parameters and improving the accuracy of the neural network prediction.
The Design of Height Control System of Fully Autonomous UAV Based on ADRC-PID Algorithm
Authors: Zang Zhibin , Ma Zhonggang , Wang Yong , Ji Fulong , Nie Haitao , Li Wenjin
Published: October 2020

In order to solve the problem of low data accuracy due to UAV height sensing equipment such as GPS, barometer, ultrasound, etc., a control system used on multi-rotor aircraft was designed to achieve UAV autonomous altitude cruise. In response to this problem, we introduce an inertial measurement unit (IMU), and use the IMU to calculate the system acceleration (ACC), and use the Kalman algorithm to predict altitude, thereby eliminating altitude drift caused by insufficient sensor accuracy and errors. In addition, the ADRC-PID joint control algorithm is also introduced to control the attitude of the aircraft, achieve control compensation, and finally control the height of the drone through the three-loop cascade PID.
Optimal view selection method based on object detection
Authors: Meng Fanwu , Xu Yichen , Huang Zhipeng , Wang Lizhong
Published: October 2020

Industrial parts detection are often studied in three-dimensional space, because of subparts occlusion, the choice of view has a great impact on the detection results. In this paper, the method of object detection combined with the 3D CAD model is proposed, the object detection model based on convolutional neural network was used to screen the visual angle, so as to eliminate the influence caused by the occlusion of parts, which provides a general method for the selection of the optimal view.
Emproved Z-Source Dynamic Voltage Restorer Based on the Minimum Energy
Authors: Li Yongxiang , Li Mengda , Ma Menglin
Published: October 2020

Dynamic voltage restorer (DVR) is a good choice to solve voltage sag problem. Aiming at the shortcomings of traditional DVR, an improved DVR model is proposed. The improved DVR took H-bridge inverter as the main frame, and the energy storage unit was based on the battery. The coupling unit directly connected the capacitor in LC filter to the power grid instead of the transformer, and connected a Z-source network between the energy storage unit and the inverter unit to improve the voltage compensation range and eliminate the impact of the series transformer. Finally, by connecting a current compensation device in parallel on the load side, combined with the minimum energy compensation control strategy, the amplitude and phase of the load voltage compensated by the improved DVR device were consistent with that before the drop. A MATLAB / Simulink simulation model is built to verify the effectiveness of the proposed improved DVR. The simulation results verify the effectiveness of the proposed improved DVR.
Research on feature extraction of veneer defects based on improved SURF algorithm
Authors: Deng Zheng Yan , Wang Yu Zeng , Zhang Hao Ran
Published: October 2020

In this paper, when the feature extraction algorithm extracts the veneer defect features, due to the veneer rotation and a large number of surface textures, the problem of poor feature matching and long time consumption occurs, and an improved SURF algorithm is proposed. The feature matching experiments of the three types of defects such as knots, dead knots, and holes in the veneer were carried out. The experiments verified that the algorithm had good rotation invariance and high efficiency when extracting veneer defect features.
Research on Zero-crossing Point Prediction Technology of CFI Based on A New Adaptive LS Algorithm
Authors: Hu Xiuming , Wan Hongyan , Zhou Ya
Published: October 2020

Fast identification of fault current parameters and accurate prediction of current waveform zero-crossing are the key technologies of controlled fault interruption(CFI). Aiming at the problem that the least squares(LS) algorithm has truncation error, this paper propose a new adaptive least square(LS) algorithm using the change rate of the fault current, avoiding the approximation of the attenuated DC decaying component. Based on the fault current simulated by MATLAB, the results show that the new algorithm has higher accuracy when the noise is not less than 40dB and the data window is more than 10ms. For the actual simulated fault current data by PSCAD, the proposed algorithm also had high accuracy, which can meet the requirements of CFI.
Exploration of building online control simulation training platform
Authors: Zhang Xiaoyan , Huang Longyang
Published: October 2020

In this paper, it is suggested to build an online air traffic control simulator training platform and incorporate it into the air traffic control simulator training system. The platform is a distributed multi-user training system, which can realize the goal of free remote training for air traffic control students on the computer. Air traffic control students access the platform through a browser and independently train control simulation skills. Teachers can query students’ training results online and in real time through the information management service platform, and give comments and remote guidance. Online control simulation training platform can enrich the training methods of air traffic control students control practical skills, effectively alleviate the problems of geographical space limitation, training time limitation, training teachers shortage and so on in control simulation training, improve the practical ability of students, and promote the safe and high-quality development of air management industry.
State Estimation of Distribution Network Based on KH–QPSO Optimization Algorithm
Authors: Xiao Fu , Liang Pei
Published: October 2020

Accurate state estimation is the basis to ensure the normal distribution network operation. To solve the nonlinear optimization problem of distribution state estimation, a state estimation model supply was established by taking the node load value and the output value of distributed power supply as state variables. This paper proposes that Krill herd-quantum behaved particle swarm optimization (KH-QPSO) can avoid premature convergence, and the minimum value is rapidly obtained. In particular, KH and QPSO allow all individuals to obtain truly global optimal solutions without introducing additional operators into the basic KH and QPSO algorithms. An IEEE-33 system is used as a simulation example, which has obvious advantages over other distribution network state estimation models, and the estimation results can provide valuable information for distribution network enterprises and managers.
Boundedness and Asymptotic Behavior of Some Nonlinear Difference Equations
Authors: Gu Juan , Liu Yinghua , Ju Guiling , Zhan Huan
Published: October 2020

The research mainly studies a class of two order nonlinear differential equation, through an extension of the discrete Bihari type inequality and Growell type inequality, through the search for appropriate inequalities, to transform the solution of the equation, get the equation boundedness and asymptotic behavior, and draw the corresponding conclusion.
Mathematical Model of Gunfire Location
Authors: Zhang Feimeng , Zhu Xiaoling
Published: October 2020

This paper makes use of the feature that the supersonic projectile will generate shock signals when flying, a system composed of 5 acoustic sensor arrays is constructed to detect the orientation and distance of the shock wave, and to determine the location of the terrorists hiding. A new method to determine the location of terrorists is established in the model. This model does not require projectile coefficient calibration, which solves a big problem in the development of the system.
Spatial Load Forecasting of Urban Power Grid Based on Regulatory Detailed Planning
Authors: Wang Kai , Zhang Guomin , Man Hongwei
Published: October 2020

Spatial load forecasting is a basic work in urban power grid planning. Spatial load forecasting should not only forecast the future load, and the spatial distribution of future load should be provided. Only based on the urban controlled detailed planning, determine the future load of each plot, so as to determine the location and capacity of the substation, model and path of line, the installation of switchgear and its input time and other decision variables, to plan.
Mathematical model and diagnosis of rotor fault in synchronous condenser
Authors: Chao Wei , Yuandi Lin , Yuliang Zhang , Hongzhong Ma
Published: October 2020

With the application of new energy in grid-connected system and the development of UHV DC transmission, the grid's requirements for reactive power regulation have gradually increased. Considering that, large-scale synchronous condensers have been put into use again. However, it is difficult to extract the characteristic signal of the inter-turn short-circuit fault in rotor windings of synchronous motors. In order to improve the stability of condensers, a certain relationship between the excitation current and the number of turns is derived using the Parker equation in the dq0 coordinate system, and the differential equation simulates the excitation current. Then the characteristic energy value of the fault signal is extracted through wavelet packet decomposition and reconstruction, and it is input to the RBF neural network for fault diagnosis. It is proved by MATLAB simulation that the diagnostic method proposed in this paper can effectively detect the degree of short-circuit faults between the turns of the rotor in condensers.
Research And Practice Of Dry Wet Combined Cooling For 600 MW Steam Turbine Generator Unit
Authors: Shengxiang Jin , Liuhu Wang , Jinsong Zhang , Qi Zhang , Qianyu li , Wei Bai , Chuan He , Daming li , Yu Xiao
Published: October 2020

Taking 600MW steam turbine generator set as an example, this paper analyzes the dry wet combined cooling scheme of auxiliary cooling water system, so as to make rational use of local limited water resources.
Steam Temperature Of 600MW Subcritical Boiler Unit Research And Practice Of Upgrading To Ultra Supercritical Parameters
Authors: Shengxiang Jin , Liuhu Wang , Jinsong Zhang , Qi Zhang , Qianyu li , Wei Bai , Chuan He , Yong Zhou , Daming li , Yu Xiao
Published: October 2020

In order to save energy and improve the working efficiency of the unit, this paper analyzes the data improvement after the steam temperature of the subcritical boiler unit rises to the ultra supercritical parameters through the transformation of the unit and makes a summary of the change of the boiler efficiency. In order to effectively improve the economic benefits, environmental protection and energy saving effect.
Design of Range Sensor for Transmission Line Fault Detection in Covered Conductor Overhead Grid
Authors: Wang Haitao , Cheng Yuan , Zhou Zandong , Ge Huangxu , Guo Yifan
Published: October 2020

As an important detection means of partial discharges, range sensor is widely used in power system in China. Due to the complex and open environment around covered conductor overhead distribution networks, misjudgement and leakage in long-distance of traditional ultrasonic sensors often occur. Aiming at this problem, an range sensor with high sensitivity and directivity is designed in this paper. In this paper, the theoretical model of the ultrasonic screening can is established by COMSOL simulation software, and the structure of the screening can is designed reasonably by analyzing the concentr-ation and directivity of the sound field of the model. In addition, based on the ultrasonic characteristics generated by partial discharge of overhead insulation wire, the ultrasonic probe with a central frequency of 40kHz was selected, and an amplification and filtering circuit was designed to reasonably improve the signal-to-noise ratio of ultrasonic detection signal. The results of laboratory test and field application show that the sensor can accurately detect and locate the partial discharge of covered conductor overhead distribution networks.
Control system of gas exhausting in tank truck
Authors: Ji Shanren , Zhong Haijian , Sun Yeqing , Xia Xinhua , Li Qing
Published: October 2020

In order to solve the problem of exhausting gas on the cleaning process of tank trucks in our country, a set of control device for exhausting gas based on Single Chip Microcomputer is developed. The device is composed of Driving Structure, Feedback Signal and Signal Processing. The Displacement Sensor, Tension Sensor, Water Level Sensor and Methane Sensor are used to generate signals, which are processed and judged by the Single Chip Microcomputer, and the corresponding instructions are sent out according to the judgment results to control the operation of the Driving Structure. Compared with the traditional Steam Fumigation Method and High-pressure Water Cleaning Method, the system is more efficient and more environmentally protection.
Analysis on Need of FO/AO on Military Production Lines
Authors: Haijun Yin , Xinghua Qiao , Xueming Su
Published: October 2020

Based on the differences on managing contents, targets, model, roles and other aspects between Planning Sheet and FO/AO, analysis is conducted on the advantages of use of FO/AO in aircraft technical management and production management and comes to the conclusion that it is important and feasible to push the use of FO/AO on military production lines all around.
Steering body-tire angle control strategy optimization of wide-body airplane ground turning
Authors: Li Jing , Wu Yuanyuan , Zhao Zhe , Lu Qing
Published: October 2020

The wide-body airplane’s unsynchronous coordination of the inner and outer steering body-tires turning angle during the ground turning process will increase the lateral force of the tires and cause side slip accidents. This paper considers the dissymmetry of the inner and outer steering body-tire turning angles during the ground turning process, calculates the theoretical turning angle mathematical relationship between nose-tire and steering body-tire, optimizes the steering body-tire control strategy from "symmetric turning angle control strategy" to "dissymmetric turning angle control strategy". By comparison, the optimized "dissymmetric turning angle control strategy" can effectively reduce the lateral force of steering body-tires during the ground turning process, decrease the risk of side slip accidents and tire abrasion. Besides, the optimized "dissymmetric turning angle control strategy" can reduce the lateral force difference between the inner and outer steering body-tires during the ground turning process, making the lateral force distribution more balanced, reducing the damage to landing gear structure caused by unbalanced lateral force and extending the service life of body landing gear.
Design of an MEMS-IMU/GNSS integrated navigation algorithm
Authors: Geng Xingshou , Tang Kanghua , Wu Meiping
Published: October 2020

In order to simplify the MEMS-IMU/GNSS integrated navigation system model, improve the navigation accuracy of the carrier under the motion condition of large Angle or frequent steering turning, two navigation modes are adopted. When GNSS signals are available, horizontal velocity and height error are used to construct three-dimensional measurement equations for partial integrated navigation. When GNSS signals are unavailable, kinematic constraint equations are introduced to assist MEMS-IMU for auxiliary navigation. Considering the problem that MEMS gyroscope zero is too large and compass effect is difficult to be reflected, a partial attitude feedback strategy is adopted for the feedback correction. The experimental results show that when GNSS signals are available, compared with the six-dimensional integrated algorithm of speed and position, the partial integrated algorithm simplifies the system model, reduces the dimension of the system, and reduces the amount of calculation, it also has better accuracy. When GNSS signals are unavailable, kinematics constraints auxiliary navigation can effectively restrain position offset, reduce navigation errors and improve navigation accuracy.
Study on Flow Characteristics and Linearization of Pneumatic High-Speed On-off Valve
Authors: Yang Jiabin , Li Xiaoning
Published: October 2020

It is hard to model the dynamic flow rate of pneumatic high-speed on-off valve due to its dead zone and nonlinearity. The average opening ratio was proposed to describe the dynamic flow rate after systematically analyzing the spool action characteristics. The mathematical relationship between flow rate, frequency, and duty cycle was established. Experimental results show that the method can accurately reflect the dynamic flow characteristics. Finally, a piecewise linearization method is designed to make the flow rate proportional to the input.
Digital twin based comfort scenario modeling of ATO controlled train
Authors: Meng Zicong , Tang Tao , Wei Guodong , Yuan Lei
Published: October 2020

Whether in Europe or China, ATO based train control system has become a trend. However, the application time of ATO is short and the user experience is insufficient. In order to better carry out system research and development, system test, system optimization and other work, the construction scheme of the simulation platform based on digital twin is proposed. In this paper, by comparing five-dimension model with three-dimension model, digital twin is built based on the five-dimension model of digital twin, and the virtual model in the five-dimension model is introduced in detail. Physical, behavioural, rule and geometric models are constructed from the four perspectives of the effect of each element in the scene on the train, the dynamic characteristics of the train, the correlation between the elements and the scene, and the visualization of the scene. Based on digital twin, the paper designs the framework of simulation platform to support ATO performance optimization and other work. The parameters in the model can be adjusted repeatedly through field data to achieve higher consistency between the model and the simulation object.
Design and application of support capability evaluation system for complex system
Authors: Wu Fei , Meng Zhe , Mao Hanyuan , Guan Xujun , Sun Shaohua
Published: October 2020

Aiming at the problem of low accuracy and effectiveness of complex system support capability assessment, an index system was constructed on the basis of studying the characteristics of support capability generation elements, in which the systematicness, comprehensiveness and the importance of key links of complex system support were considered, a complex system supportability evaluation model was proposed based on weight scores and key levels, and the score and level of the complex system supportability evaluation were obtained through comprehensive evaluation. A corresponding evaluation system was designed which provided the means and support for the informatization of support capability evaluation of complex systems.
Development of metallized three-directional fibre Bragg grating strain sensor
Authors: Chen D.M. , Dai X.N. , Tang Z.B.
Published: October 2020

The theory and application of fiber Bragg grating sensors are studied in this paper. The three-directional metallized fiber Bragg grating strain sensor with temperature compensation has been developed. The Metallization Technology of fiber grating is studied. The Metallization Technology Scheme of fiber grating is discussed in detail. The electroless composite nickel-plating process and the formula of nickel-plating process are given. A metal fiber grating strain sensor with temperature compensation is developed. The metal fiber grating sensor is fixed to the substrate by laser welding, and a one-way metal fiber grating strain sensor with temperature compensation is formed. Three unidirectional metallized fiber Bragg grating strain sensors are connected with the developed common welding blocks to form a three-directional strain flower. Comparing with resistance strain rosette stress test and its application in ship structure stress monitoring, the fiber grating strain sensor developed in this paper fully meets the requirements of large-scale structure long-term strain monitoring.
Evaluation of operation lifetime of microwave low noise NPN bipolar junction transistor
Authors: Wei Zhichao , Sun Yi , Zhang Hongwei , Xue Pengchao , Sun Yabin
Published: October 2020

In this paper, the lifetime of microwave low noise NPN bipolar junction transistor under three operation modes are deeply investigated. Experiment results shows that the electrical parameters keep nearly unchanged when a steady electrical stress is applied over 2000 h at 125°C. The junction temperature (Tj) is found to have a significant influence on the operation lifetime. The samples begin to fail once Tj is higher than 225°C. Furthermore, the higher the junction temperature is, the earlier the failure occurs, and the shorter the lifetime is. The accumulated damages near Si/SiO2 interface around BE junction are contributed to the failure under high temperature. The estimated mean time to failure based on the failure data under high Tj is higher than that from non-failure data under low Tj. HTRB stress are found to be able to result in damages around LOCOS edge under BC junction, but the induced variation of related electrical parameters is still far below the specified failure criterion. All these data obtained here can provide a reliability foundation for bipolar transistors.
Laser ultrasonic testing for inspection of curved surface samples based on synthetic aperture focusing
Authors: ting Yang , wen He , jianzong He , haohui He , jinjing Yuan , Wan Zhang , Ling Yuan , Hongchao Zhang
Published: October 2020

Synthetic Aperture Focusing (SAFT) is one of the methods to improve the spatial resolution in laser ultrasound. However, the research on laser ultrasonic SAFT technology is mainly focused on block or plate samples. In order to study the detection capability of laser ultrasonic SAFT technology on the samples with curved surface, a finite element simulation model of curved surface samples with sub millimeters internal defects is established. And then the laser ultrasound field is obtained through numerical simulation. At last the SAFT algorithm was performed to image the defects in the samples. The results show that laser ultrasonic SAFT technology can image curved surface samples with sub millimeters internal defects. The results provide a reference for the practical application of laser ultrasonic SAFT technology.
Comparison and Analysis of Oil Tank Test Results by PAC and Vallen Acoustic Emission Instrumentations
Authors: Zhang Shijie , Pan Meng , He Zhi , Deng Di , Han Jiakai
Published: October 2020

In this article, two acoustic emission instruments, PAC and Vallen acoustic emission instruments, are applied to carry on the test of crude oil storage tanks. Four experiments contents have carried out such as active defect test, corrosion test, vibration test, leak test. And compare and analyze the acoustic signal characteristics of the above four detection contents of two acoustic emission instruments. The differences and advantages and disadvantages of the four detected acoustic signals of the two acoustic emission detectors are summarized. The research results provide certain basic test support for the improvement and development of acoustic emission testing equipments and supporting software.
Steady State Energy Flow Analysis for Energy Internet Planning
Authors: Ji Xiaoqing , Wang Fei , Song Feng , Liu Junxu , Liu Jie , Xiong Dang
Published: October 2020

The planning and design of the energy Internet is a primary and significant link of the energy Internet. For this paper, its basic work is to design, analyse and calculate the energy flow of the network. In this paper, a typical energy flow analysis model of power-gas interconnection system is established, and the algorithm of the model is given to solve the problem. Finally, the feasibility of the algorithm is verified by a classical example of electricity - gas interconnection.
Research on IACA of distribution network fault location
Authors: Liu Xue , Jia Jun , Wang Jian
Published: October 2020

In power system, the probability of distribution network failure is the highest, which will directly affect the power consumption experience of customers. The timely and accurate fault location of distribution network is very important to improve the reliability of power supply. In this paper, firstly, the switch function and evaluation function of distribution network fault location are discussed. ACA(Ant Colony Algorithm) algorithm has some defects such as premature convergence. In order to solve this problem, the IACA(Improvement Ant Colony Algorithm) method is proposed. Finally, the feasibility and effectiveness of the new method are verified by establishing a simple distribution network model.
Research on Constitutive Model of Unsaturated Sand
Authors: weihua Zhang , chenggang Zhao , yanhua Gao , chunlei Zhao
Published: October 2020

For unsaturated sand, due to the existence of suction, under low confining pressure, it has a large volume change during shearing and obvious dilatancy and peak characteristic points appear in the whole stress-strain behavior. Based on the above situation, the boundary surface constitutive model of unsaturated sand is established in general stress space and triaxial stress space based on phase transition state and hydraulic-mechanical coupling. The model has smooth transition among different saturation state and model parameters are easily calibrated via common triaxial tests and some other simple tests.
Analysis of elementary school students’ mathematical resilience during learning during the covid 19 Pandemic
Authors: Rahayu G D S , Altaftazani D H , Kelana J B , Firdaus A R , Fauzi M R
Published: October 2020

This research is motivated by a change in learning methods that were initially face-to-face to online learning that resulted from the COVOD-19 outbreak. The purpose of this study was to analyze the mathematical resilience of elementary school students during learning during the COVOD-19 pandemic. The method used in this research is descriptive method with 36 elementary school students as subjects in one of the primary schools in Majalengka district, West Java, Indonesia. The results of this study, mathematics resilience of elementary school students is in the medium category. The findings related to mathematics resilience of elementary school students namely resilience is not only influenced by the complexity of the material and changes in learning methods. However other factors such as the packaging of learning by the teacher, the media used by the teacher, and the communication used by the teacher also affect the mathematics resilience of elementary school students.
Math study habits on deaf learners
Authors: Leton S I , Jagom Y O , Dosinaeng W B N
Published: October 2020

The purpose of this study was to obtain a picture of mathematics learning habits for deaf students. The subjects in this study were 99 deaf students taken purposively in across 4 schools, including, SLB B Karya Murni Ruteng, SMPLBN Semarang, SLB B Don Bosco Wonosobo, and SLB B Denaupakara Wonosobo. The research involved a quantitative and qualitative research design where the quantitative data was taken from a set of questionnaires that included a commitment attitude questionnaire, a disciplinary attitude questionnaire and a commitment attitude questionnaire in learning mathematics; meanwhile, a qualitative data was gained through the observation of learning activities at their schools and at their boarding house. The results of the analysis showed that students’ consistent attitude, disciplined attitude, and attitude of commitment in learning mathematics were in a good category; therefore, we assumed that deaf students maintained good habits in learning mathematics. By having these good study habits, they were expected to acquire basic skills related to basic arithmetic operations that will be applied in life skills such as sewing, making patterns, carpentry, and automotive. Also, good study habits might improve their cognitive skills that impacted their study result and learning achievements that in turn enable them to reach their goals.
Responses of students with special needs to online mathematics leaning during pandemic
Authors: Balkist P S , Agustiani N
Published: October 2020

This study aims to understand the responses of students with special needs to learn mathematics during pandemic Covid-19 in inclusive schools. The method of research is descriptive qualitative. The subject of this study were three students with special needs in class X in the inclusive school SMA N 1 Sukabumi, those are a student with visual impairment, a student with physical disabilities, and a student with mental retardation. The results showed that students were enthusiastic about learning online, and were good enough in the timeliness of collection the task also the accuracy of the content. However, enthusiasm, timeliness, and accuracy of content decreased over time, because it lacks direct interaction and innovation of media online learning.
Project-based learning in mathematics: A literatur review
Authors: Fisher D , Kusumah Y S , Dahlan J A
Published: October 2020

This study is a literature study with a descriptive qualitative research with library research that attempts to describe project-based learning in mathematics learning. In this literature study research the author uses various written sources such as articles, journals and documents that are relevant to the study in this study. This study focuses on the characteristics of project-based learning, steps of project-based learning, and examples of project-based learning assessments, Differences in Project-Based Learning Emphasis and Traditional Learning, Examples of the application of project-based learning in mathematics. The next research that is interesting to be developed as research is project-based learning in increasing High Order Mathematical Thinking (HOTs).
Problem solving and cognitive style: An error analysis
Authors: Ratnaningsih N , Hidayat E , Santika S
Published: October 2020

Problem-solving and cognitive style are two things that are important to note, but the reality is rarely considered especially cognitive style. Student cognitive style can influence problem-solving abilities. This study aims to investigate student errors based on Newman in problem solving, in terms of independent and dependent field cognitive style. The study was conducted on junior high school students in Indonesia, the method used is exploratory involving 2 Subject. Subjects are taken from independent and dependent field style cognitive groups. Stages of problem-solving according to Polya’s includes: understanding the problem, devising a plan, carrying out the plan, and look back. Errors according to Newman include errors in reading, comprehension, transformation, process skills and encoding. Data were collected using the Group Embedded Figure Test (GEFT) and problem-solving test. The conclusion shows that subject with field dependent cognitive style with the initials SFD tend to make errors at the transformation stage in making models, process skills in manipulating algebra and calculation processes, and conclusions for making errors in the previous stage. Whereas subject with independent field cognitive style with the initials SFI tend to make errors at the process skill stage in manipulating algebra and calculation processes.
The development of IT-based learning evaluation media using wondershare quiz creator on the statistics course
Authors: Rodliyah I , Saraswati S
Published: October 2020

The aim of this research is to produce an IT-based learning evaluation media for Hasyim Asy’ari University students, especially mathematics education study program by using the ADDIE model which consists of five stages, namely (1) analysis, (2) design, (3) development, (4) implementation, and (5) evaluation. The subjects include media experts, material experts, and students as media users. The research instrument used was a questionnaire of product quality filled out by students and also a validation sheet filled out by Media and Material Experts. Data processing is performed after the product data has been successfully obtained. The data is then analyzed by using the percentage formula. Through the data analysis, the percentage obtained by media expert validation was 90.36%, and material expert was 91.43%. The practicality results at the implementation phase showed the percentage of assessment was 92.27% while the effectiveness results of classical completeness was 87.36%. The results of the Validity and Reliability analysis of each item were declared valid and reliable with an Alpha value of 0.943. So, based on the eligibility criteria guidelines, overall the IT-Based Learning evaluation media in the form of the Wondershare Quiz Creator is declared worthy to be use.
Mathematics learning in elementary school through engineering design process method with STEM approach
Authors: Firdaus A R , Wardani D S , Altaftazani D H , Kelana J B , Rahayu G D S
Published: October 2020

Education is developed to prepare students to face possible problems that might arise in the future. Recent trends show that many job opportunities in the fields of Science, Technology, Engineering, and Mathematics exist in the industrial world, but most of them think that school graduates are not in line with the needs in the field. One of them is because people are too focused on one area. Therefore we need the development of learning that can integrate various subjects, especially in the fields of science, technology, engineering, and mathematic. This research is intended to describe the development of mathematics learning through engineering design process method with STEM approachs. The method used in the form of a descriptive method with research subjects for six-grade elementary school students in Indonesia. The learning is based on mathematics about surface area and natural science about electricity. Through this research, it is produced that learning based on science, technology, engineering, and mathematics can provide exciting experiences and increase their interest in learning mathematics more deeply.
Acceleration analysis of population growth using winter’s method: case study of lombok island
Authors: Negara H R P , Syaharuddin  , Ibrahim M , Kurniawati K R A , Mandailina V , Pramita D , Abdillah  , Mahsup  , Ahmad  , Saddam
Published: October 2020

The research aims to analyze the acceleration of the population growth in Lombok which consists of 5 districts/cities using forecasting system by constructing the winter’s method in the form of a GUI Multiple Forecasting System (G-MFS) based on Matlab by calculating the indicator level of accuracy to find predictive data for the next 10 years. At the data simulation stage, researchers used population data over the last 11 years. The evaluation of forecasting results is calculated by calculating the value of Mean Absolute Percentage Error (MAPE) with 27 attempts through modified Winter parameter values. From the simulation data obtained the most optimal parameter value is α, β, and γ sequential values of 0.9, 0.5, and 0.9. Then with the value of the parameter obtained MAPE value of 1.25%. Furthermore, it can be noted that for the next 10 years the increase in the population of Lombok Island on average of 1.49%, with the average East Lombok district details of 1.15%, the average West Lombok district by 1.17%, the average central Lombok district of 0.98%, the North Lombok district averaged 0.98%, and the average Mataram city of 3.05%. These results suggest that the simulated and numeric techniques using the GUI of MATLAB provide quite accurate results. In subsequent research, it is necessary to do predictions based on the number of births, the number of deaths, the number of transmigration, the amount of productive and non-productive, and other data series that is more complex so that it will be seen how the development of the population productivity on the island of Lombok.
Magic covering and edge magic labelling and its application
Authors: Farida A , Indah R P , Sudibyo N A
Published: October 2020

Graph theory is developing very rapidly, especially in labelling graphs. This is proven by the number of researches examining graph labelling. In graphs labelling, research focuses on developing theories. On the other hand, graph labelling (magic covering and edge super magic labelling) has a useful application. This paper will discuss the magic covering of a simple graph (Domino graph) and edge magic labelling on a simple graph (Domino graph). The conclusion is that the magic covering can be applied to a secret sharing scheme, and also edge magic labelling can be applied to ruler models.
Learning geometry of plane and space through Timor Tengah Selatan culture
Authors: Fernandez A J , Fernandez M
Published: October 2020

Mathematics learning is inseparable from local culture. In the local culture in Timor Tengah Selatan regency, there are geometric shapes of plane and spaces contained in local buildings or customs. The habit of measuring gardens. The habit of making roofs and fences is a form of Geometry. This research aims to examine the geometrical shapes contained in traditional houses, LOPO. The research was conducted at Benteng None. The type of this research is qualitative research. The data collection method uses observation and interview techniques. Data were analyzed by data reduction, data presentation, data verification and conclusion. The results showed that there were several Geometry shapes of plane and space at Benteng None, Timor Tengah Selatan Regency.
Mathematical model of coral reefs with fish harvesting effect
Authors: Zikkah R N , Anggriani N , Supriatna A K
Published: October 2020

The degradation of coral reefs is becoming increasingly alarming. If left unchecked, there will be an imbalance of the marine ecosystem. Many factors are killing the coral reefs. There is nature factor such as global warming and human activities factor such as destructive fishing. In this paper, we proposed model coral reefs with a system of the nonlinear ordinary differential equation between five populations, namely coral reefs, parrotfish, macroalgae, algal turfs, and crown of thorns starfish in the Great Barrier Reef, Coral Sea. We consider biological interactions such as predator-prey relationships between the crown of thorns starfish and coral reefs, and macroalgae grazers on coral reefs. We consider destructive fishing that damage the coral. Using the standard dynamic system theory, we determined the stability of the system with and without fishing. We show numerical simulation and sensitivity analysis to evaluate the investigation results to conclude the effect of the destructive fishery on coral reefs.
Developing math games media using scratch language
Authors: Bernard M , Setiawan W
Published: October 2020

Problems faced by students on mathematical problems always occur due to process errors because for those with enough knowledge to memorize formulas, then their job is only to insert numbers in formulas, and in fact, even when they use them they are not able to develop reasonable process stages. The purpose of this media learning, the existence of a strong positive influence they can understand mathematics, able to tune in concepts and be able to evaluate if there are steps in the wrong process then they correct mistakes. This study aims to develop the potential of prospective teachers or students to create ICT-based interactive media in mathematical games, using the ADDIE model of Analysis, Design, Development, Implementation, and Evaluation to see and guide students in making better products. From the results of the study that there is a positive influence when using media based on the average class at pretest 70.74 and post-test 82.69 with paired t-test with a significant value of 0,000 <0.05. and there is also an increase in the ability to solve the context of mathematical problems using the scratch program language based on a decrease in the indicators of student difficulties.
The effect experiential learning model based concrete-pictorial-abstract (EL-CPA) on mathematics attitude of deaf students
Authors: Amril L O , Darhim  , Juandi D
Published: October 2020

Mathematical attitude is a psychological response that arises when students interact in learning mathematics in school. For deaf students, attitudes towards mathematics have an important role in their success in learning mathematics. Deaf students are students who have hearing loss and verbal communication. The experts revealed that the visual potential of deaf students is a potential that can be utilized in mathematics learning activities. One learning model that utilizes the visual potential of deaf students is the EL-CPA model. The research aims to determine the effect of the application of the EL-CPA model on the mathematical attitudes of deaf students in Special Schools. This research is a quasi-experimental study with a sample of 20 deaf students. The sample was chosen randomly from 10 Special Schools in the city of Bogor. Data were analyzed using non-parametric statistics through binomial tests. The results of this study indicate that there is an effect of the EL-CPA model on the mathematical attitudes of deaf students with a Sig value of 0.024. Therefore, researchers recommend applying the EL-CPA learning model for deaf students in special schools.
Students’ understanding of the concept of function and mapping
Authors: Widada W , Herawati A , Fata R , Nurhasanah S , Yanty E P , Suharno A S
Published: October 2020

Function is a concept that is very much related to daily life. Likewise with the concept of mapping. The purpose of this study is to describe students’ understanding of the concept of function and mapping by students who are at a high level (ie extended-trans level). The student is the subject of this study. This research is exploring the ability of research subjects. The research subjects were taken from mathematics education students at Bengkulu University. We selected one subject of research, Mg. Student was interviewed in depth about the concept of function. Data were analyzed based on genetic decomposition. The results of this study are that students are able to present an overview of the concept of function with a broad extension level. The function from the set A to B is the set f whose members are sequential pairs of the two cross-sets of non-empty sets A and B such that (a, b) and (a, b ′) elements of f then b = b′. Also able to make a simplification in the form of mapping definition, which states that the domain of function f is the set A. The conclusion of this study is that high-level students have an in-depth understanding of the concept of function. He is able to compile extensive extensions. Also, make the exact simulations.
Application of geogebra software to improve problem-solving skills in analytic geometry in prospective teachers students
Authors: Sugandi A I , Bernard M
Published: October 2020

This study aims to examine the improvement in thinking skills problem solving of prospective teacher students in learning analytic geometry using GeoGebra software. The population in this study were all students of IKIP Siliwangi, with a sample of class One class 2018 totalling 35 people. The instrument used in this study was a test in the form of a 5-item description question and a non-test in the form of a Likert scale. Based on the results of data processing, it can be concluded that the use of GeoGebra software is effective in improving problem-solving skills in analytic geometry learning. Overall, students’ responses to the use of GeoGebra software in learning analytic geometry courses are in a very strong category. The highest indicator of student attitudes towards the use of GeoGebra software is achieved on the indicator of interest in the media and the indicator that has the lowest percentage lies in the indicator of image use.
Students’ misconception of HOTS problems in teaching and learning of mathematics
Authors: Tanujaya B , Mumu J
Published: October 2020

The purpose of the research was to analyze the opinions of mathematics education students about HOTS questions. The method used in this research was a qualitative research method, using a descriptive approach. The subjects in this study were 21 students, were selected purposively. The data collection instrument is open-ended set of questions using the Google classroom application. Triangulation was conducted through interviews with four lecturers was conducted in order to increase the validation of the research. The results showed that there were two groups of student opinions about the HOTS question; difficult questions and three top-level levels of Bloom’s taxonomy. However, there are misconceptions of the students interpreting difficult problems and Bloom’s taxonomy level about HOTS problems. Not all difficult problems can be classified as HOTS problems, nor all problems on three top-level questions of Bloom’s taxonomy be categorized as HOTS problems.