bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feature selection procedures for combined density functional theory—artificial neural network schemes
Authors: Nemnes George Alexandru , Filipoiu Nicolae , Sipica Valentin 
Published: March 2021

Abstract
We propose a workflow which includes the essential step of feature selection in order to optimize combined density functional theory—machine learning schemes (DFT-ML). Here, the energy gaps of hybrid graphene—boron nitride nanoflakes with randomly distributed domains are predicted using artificial neural networks (ANNs). The training data is obtained by associating structural information to the target quantity of interest, i.e. the energy gap, obtained by DFT calculations. The selection of proper feature vectors is important for an accurate and efficient ANN model. However, finding an optimal set of features is generally not trivial. We compare different approaches for selecting the feature vectors, ranging from random selection of the features to guided approaches like removing the features with lowest variance and by using the mutual information regression selection technique. We show that the feature selection procedures provides a significant reduction of the input space dimensionality. In addition, a selection method based on the ranking of the cutting radius is proposed and evaluated. This may not only be important for establishing optimal ANN models, but may offer insights into the minimum information required to map certain targeted properties.
Colorless movement of focal spot with arbitrary velocity based on mirrors with special shape
Authors: Fan Quanping , Wen Shenglin , Wang Shaoyi , Yang Zuhua , Chen Yong , Liu Dongxiao , Wei Lai 
Published: March 2021

Abstract
Focal spot with moving speed is a new concept proposed in recent years, which has many applications in physics of intense field. The current method is to control the moving speed of focal spot by chirped pulse technique and chromatic aberration focusing, which suffers from the change of frequency components with the movement of focal spot. In this paper, we propose a method to realize the colorless movement of focal spot at arbitrary speed by using two kinds of mirrors. One is an aspherical mirror with long focal depth and the other is a stepped mirror. For a specific moving speed, we derive the relationship between the surface of aspherical mirror and the wavefront of laser by the geometrical optics. The stepped mirror is used to form stepped wavefront to separate the relationship between the shape of wavefront and the direction of laser. Time-dependent simulations are carried out to verify the real focusing property after considering diffraction effects, and focal spots with moving speed of 0.5c, 2c and −c are obtained.
Spectrum of Cuscuton bounce
Authors: Kim J. Leo , Geshnizjani Ghazal 
Published: March 2021

Abstract
It has been recently shown that a cosmological bounce model based on Cuscuton gravity does not have any ghosts or curvature instabilities. We explore whether Cuscuton bounce can provide an alternative to inflation for generating near scale-invariant scalar perturbations. While a single field Cuscuton bounce generically produces a strongly blue power spectrum (for a variety of initial/boundary conditions), we demonstrate that scale-invariant entropy modes can be generated in a spectator field that starts in adiabatic vacuum, and is kinetically coupled to the primary field. Furthermore, our solution has no singularity, nor requires an ad hoc matching condition. We also study the generation of tensor modes (or gravitational waves) in Cuscuton bounce and show that while they are stable, similar to other bounce models, the produced spectrum is strongly blue and unobservable.
Towards cosmological constraints from the compressed modal bispectrum: a robust comparison of real-space bispectrum estimators
Authors: Byun Joyce , Oddo Andrea , Porciani Cristiano , Sefusatti Emiliano 
Published: March 2021

Abstract
Higher-order clustering statistics, like the galaxy bispectrum, can add complementary cosmological information to what is accessible with two-point statistics, like the power spectrum.
While the standard way of measuring the bispectrum involves estimating a bispectrum value in a large number of Fourier triangle bins, the compressed modal bispectrum approximates the bispectrum as a linear combination of basis functions and estimates the expansion coefficients on the chosen basis.
In this work, we compare the two estimators by using parallel pipelines to analyze the real-space halo bispectrum measured in a suite of N-body simulations corresponding to a total volume of ∼ 1,000 h
-3 Gpc3, with covariance matrices estimated from 10,000 mock halo catalogs.
We find that the modal bispectrum yields constraints that are consistent and competitive with the standard bispectrum analysis: for the halo bias and shot noise parameters within the tree-level halo bispectrum model up to k
max ≈ 0.06 (0.10) h Mpc-1, only 6 (10) modal expansion coefficients are necessary to obtain constraints equivalent to the standard bispectrum estimator using ∼ 20 to 1,600 triangle bins, depending on the bin width.
For this work, we have implemented a modal estimator pipeline using Markov Chain Monte Carlo simulations for the first time, and we discuss in detail how the parameter posteriors and modal expansion are robust to, or sensitive to, several user settings within the modal bispectrum pipeline.
The combination of the highly efficient compression that is achieved and the large number of mock catalogs available allows us to quantify how our modal bispectrum constraints depend on the number of mocks that are used to estimate covariance matrices and the functional form of the likelihood.
Spatial vortex four-wave mixing in a five-level atomic system
Authors: Gan Shoufei 
Published: March 2021

Abstract
We propose a scheme for modulating the spatial vortex four-wave mixing (FWM) in a five-level atomic system. During nonlinear FWM process, we find the FWM field can be easily manipulated by adjusting the corresponding parameters. Practically, the vortex phase can be spatially modulated. Thus, our results may be helpful to study nonlinear quantum phenomena based on orbital angular momentum light.
Gender differences in digital literacy among prospective physics teachers
Authors: Rizal R , Rusdiana D , Setiawan W , Siahaan P , Ridwan I M 
Published: March 2021

Abstract
The rapid development of digital technology has stimulated teachers with the number of competencies called digital literacy. The purpose of this study was to describe gender differences in digital literacy among prospective physics teachers. This research was conducted using a descriptive method involving 71 prospective physics teachers at a university in Tasikmalaya. They consisted of 31 males and 40 females with age 19-21 years old. Data was collected using valid digital literacy tests and interview. The collected data was processed by determining the average score of male and female students then analyzed through interview. The results showed that the mean of male’s digital literacy was higher than female. The males had a mean 57 (moderate category) and the females had a mean 53 (low category). There was a difference in digital literacy between males and females prospective physics teachers. These distinctions were influenced by their tendency in using digital technology. Some recommendations were delivered to prospective physics teachers, especially for females. They should effectively increase their digital technology use and appropriate training in the use of digital technology is needed to achieve a higher level of digital literacy.
Formative assessment of fruitful criteria in physics learning based on pedagogy subject matter approach
Authors: Suhendi H Y , Aulia M R , Kuntadi D , Mulhayatiah D , Nasrudin D , Malik A , Ardiansyah R 
Published: March 2021

Abstract
Student knowledge criteria is one aspect that shows the success of a learning process. According to pedagogy subject matter, learning is successful if the students’ knowledge has reached the fruitful criteria. This research aims to determine the formative assessment of fruitful criteria in work and energy learning based on directing motives and syntactic aspects. The research method used is qualitative with a case study approach. Data were analyzed using discourse analysis. Sample of this research are teacher and students at one school in the Bandung district was conducted on the teaching motives of educators, aspects of teaching materials and formative assessment used in learning activities with data collection techniques in the form of direct and indirect observation using a video recorder with an observation sheet and indicator motives, aspects and criteria sheet. The analysis is done by making a transcript of learning activities, making basic texts with refinement, preparing micro and macro propositions so that the learning macro structure is obtained. Furthermore, the analysis is carried out with reference to the indicators of each motif, aspect, and criteria. The results showed there were six formative assessment questions of fruitful criteria based on directing motives and syntactic aspects or appears at 37.5% of the total fruitful criteria formative assessment. The researcher suggests doing research on other criteria so that it can be known in full the types of questions for formative assessment based on the pedagogy subject matter approach.
The development of virtual conceptual change laboratory (VCCLab) for conception reconstruction through lab virtual activity
Authors: Putri K L , Suhandi A , Samsudin A , Surtiana Y 
Published: March 2021

Abstract
The research aimed to get a valid and tested VCCLab model product complete with syntax and supportive materials. This research is encouraged by the need for a VCCLab model for remedial teaching oriented towards remediation of students’ misconceptions through the mode of virtual laboratory activity. The research method used is research & development which consists of four stages, namely: Need Analysis, Product Development, Field Testing, and Product Revision. From the development research process, the VCCLab model product is produced with syntax consisting of five stages of lab activity. The results of expert judgement on the VCCLab model product indicate that the VCCLab model and supporting materials have a construct and content validity. The results of limited field testing indicate that the use of the VCCLab model in remedial teaching activities with the mode of virtual lab activity has high effectiveness in remediating students’ misconceptions regarding the concept of parallel electric circuit. Another field testing result is that there is no gender bias in the use of the VCCLab model in the students’ conception reconstruction process related to the physics concept being reviewed.
Inventory of scientific literacy ability of junior high school students based on the evaluation of PISA framework competency criteria
Authors: Amini S , Sinaga P 
Published: March 2021

Abstract
This study aims to interpret the inventory of students’ scientific literacy ability. It used systematic review method of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Descriptive technique based on the percentage of students’ scientific literacy abilities was used to analyse the data. Based on the results of PISA in 2012 and 2015 students’ scientific literacy abilities were in very low level, that is, 41.53%. Specifically, based on the results of the competency aspects of 2012 PISA, the students’ abilities to identify scientific problems and to use scientific evidence were in moderate category, while the students’ abilities to explain the phenomena scientifically were in low category. On the other hand, based on the results of the competency aspects of 2015 and 2018 PISA, the students’ abilities to explain phenomena scientific, to evaluate and design scientifically, and to interpret data and scientific evidence obtained a percentage value of 34.24%, 34.70%, and 40.15% respectively, and all of them were in very low category. The implication of this study is that the students’ overall scientific literacy abilities are still very low. Accordingly, there must be effective measures to improve students’ scientific literacy through a set of learning innovations and strategies.
Conceptual progression of K-10 student on the free-falling objects acceleration concept as an effect of E-CDCCText
Authors: Setiono I A , Suhandi A , Liliawati W 
Published: March 2021

Abstract
The purpose of this study was to obtain the impact of using Electronic Conceptual Development Conceptual Change Text (E-CDCCText) related to the concept of acceleration of free-falling objects on K-10 students. E-CDCCText consists of seven parts. The third part is a conceptual development text. The fourth, fifth, and sixth parts are conceptual change text added with cognitive conflict and scientific explanation. The method used is pre-experiment with one group of three test designs. Research subjects were 32 K-10 students whose average age is 14-15 years old, consisting of 20 female and 12 male students in Yogyakarta. The research subjects were selected by random sampling techniques for the class. Data is collected based on parallel conception tests in the four-tier test format on the free-falling objects acceleration concept. These results indicate that E-CDCCText has high effectiveness in remediating misconceptions. In general, the use of E-CDCCText has been effective in facilitating the conceptual progression of students in the type of well progression (75%). The use of E-CDCCText does not cause gender bias between female and male students. E-CDCCText has been effective in facilitating the conceptual progression of female and male students in the type of well progression (75%). E-CDCCText can effectively use in conceptual development and conceptual changes activities on the free-falling objects acceleration concept.
Technological pedagogical and content knowledge (TPACK) of prospective physics teachers in distance learning: self-perception and video observation
Authors: Efwinda S , Mannan M N 
Published: March 2021

Abstract
Learning from home in the Covid-19 Pandemic period posed a variety of challenges both for teachers and for students. The ability of teachers to utilize technology in learning is very necessary so that distance learning can run effectively. This study aims to determine the self-perceptions and skills of prospective physics teachers in the Technological Pedagogical and Content Knowledge Knowledge (TPACK) framework to support distance learning. This research is a quantitative research. Self-Perceptions were screened using a questionnaire, 128 research subjects were Physics education students in Samarinda, Indonesia. Then, the skills of prospective physics teachers in the TPACK framework to support distance learning were sought through video observations with 30 research subjects from 128 previous students. Based on data analysis, self-perceptions of prospective physics teachers within the TPACK framework in sufficient category. There is a significant difference between the self-perception of prospective physics teachers who have taken computer training and have never taken computer training. The skills of prospective physics teachers in the TPACK framework are also in the sufficient category. Based on this, educational institutions need to increase learning and training for prospective physics teachers to integrate technology in learning so that their TPACK skills can be improved.
Profile of early ICT capabilities of prospective physics teachers through basic physics learning in Makassar
Authors: Ma’ruf M , Setiawan A , Suhandi A , Siahaan P 
Published: March 2021

Abstract
This study identifies the initial ICT skills and basic competencies of learning technology for students in learning basic physics. This research was conducted in three different universities in Makassar Indonesia. The research instrument is a test instrument for the basic competency test of learning technology, and a non-test instrument in the form of a learning technology capability questionnaire. The results showed that the average percentage of student learning technology competence in three tertiary institutions in Makassar was level 1 with a percentage of 94.39%; level 2 57.50%; level 3 78.17%; level 4 67.77%; level 5 76.03%; and level 6 67.55%. This shows that the competency of student learning technology for level 1 is in the very good category, and levels 3 and 5 are in the good category. While at level 4, and 6 are in the medium category, while at level 2 it is still in the bad category. The initial ability of learning technology on the attitude aspect is in the high category while the social emotional aspect is also in the moderate category. This shows that the use of learning technology really needs special attention to the social emotional aspects, especially ethics. Therefore, it can be said that the relationship between the initial ability of student learning technology and its use as a medium for learning basic physics is very close. The ability of good learning technology will have the potential for the use of good learning technology.
Student visualization in solving geometry problem: the case of reflection
Authors: Yurmalia D , Herman T 
Published: March 2021

Abstract
Visualization is a mental act representing a visual information. In solving geometry problem, we need visualization to identify and illustrate the information. This study aimed to analyse student visualization in solving the reflection problems. We studied a female high school athlete at grade eleven. There were three steps in this study. First, we designed two reflection problems. Next, we assessed and interviewed her by semi structure interviewed. Finally, we analysed student spatial visual comparing to types of visualization by Presmeg. Lot of athletes do not have time enough in learning about some topic in their class, so we have to find an appropriate approach to led her in learning activity for creating an efective learning. We found that she has two types of visualization that are pattern imagery and kinaesthetic imagery. In the future, we can design instructional tasks that are convenient for this visualizer.
Prior knowledge of students in analytical geometry in terms of gender analyzed using the Rasch model
Authors: Sudihartinih E , Prabawanto S 
Published: March 2021

Abstract
The purpose of this study is to describe the prior mathematical proficiency of students in terms of gender analyzed by the Rasch model. Participants consisted of a class of second-semester students who contacted analytic geometry courses comprised of 11 men and 29 women at one of the universities in Indonesia. The research instrument was a test item describing five questions about points and lines in the plane. The results showed students answered questions according to their level of ability, and there was no gender bias. Therefore in learning that will carried out in groups should be heterogeneous from the prior level of mathematical and gender prior knowledge.
Blended learning based on ebook integrated Youtube in learning mathematics
Authors: Fitriani  , Fatimah S , Herman T 
Published: March 2021

Abstract
This study aims to develop an blended learning based on E-book integrated Youtube in mathematics learning geometry material that is valid, practical and effective and to determine students’ readiness for the use of blended learning at the E-learning stage in mathematics learning. This research is a development research design development model used is the Analyze, Design, Development, Implementation and Evaluation model. And to see the readiness of students towards the use of Blended Learning at the E-learning stage the researchers used a type of qualitative research using descriptive research methods. This research was conducted for high school students in Negeri 1 Langsa City. The instruments used in this study were (1) Plans for implementing learning and E-books integrated with Youtube; (2) expert validation sheets, (3) teacher and student observation sheets; (4) tests; and (5) questionnaire. The results of the research show that developing a blended learning based on E-book integrated Youtube in mathematics learning geometry materia meets valid, practical and effective criteria. The results of the students’ readiness questionnaire towards the use of blended learning in the E-learning stage in mathematics learning showed results on an average indicator with a value of 72.69% with a good category.
The ability of mathematical problem solving of junior high school students in situation based learning and discovery learning
Authors: Hasanah A N , Priatna N , Yulianti K 
Published: March 2021

Abstract
The ability of mathematical problem solving is needed in learning mathematics. However, the facts show that its is still low. This study aims to determine the achievement of mathematical problem solving abilities of students who obtains situation based learning model and discovery learning models. The method of this study was quasi-experimental study with a post-test only control group design. The subject of this research was 64 students in class 8th of one junior high school in Garut, that was chosen by purposive sampling technique. The data was collected through the results of validated tests, interviews and observations. Mann-Whitney test was performed on quantitative data obtained, and description on qualitative data. The results show that the achievement of mathematical problem solving abilities of students who obtained situation based learning was no higher rather than students who obtained discovery learning. The causal factors because two models (1) are student-centered, (2) conducted in groups so that students can share strategies and information with their peers, (3) mathematical problem-solving questions are facilitated at each meeting, (4) have steps that support the use of indicators of problem solving ability in this study, (5) involve several factors that contribute to one’s success in solving mathematical problems.
Hawthorne effect and mathematical software based learning: a meta-analysis study
Authors: Tamur M , Kusumah Y S , Juandi D , Wijaya T T , Nurjaman A , Samura A O 
Published: March 2021

AbstractThe use of mathematical software in learning has been widely applied. This meta-analysis study was conducted to examine the “Hawthorne effect”, or the novelty of using mathematical software in learning. Related databases are sought for studies that qualify for examining the effects of using mathematical software compared to traditional teaching on students’ mathematical abilities. Random-effect models with 95% confidence intervals (CIs) were estimated. 40 effect sizes were analyzed from 40 primary studies that have been published in journals, or national and international proceedings from 2010 to 2020, and a total of 3072 students were included in this meta-analysis. The Comprehensive Meta-Analysis (CMA) program is used to assist analysis. As a result of the study, the overall effect size was 0.886 with a standard error of 0.092. The results of the follow-up analysis showed that the duration of the treatment was related to the use of mathematical software. It was found that the use of mathematical software given in the span of 0 - 4 weeks (effect size = 1.193) was more effective if carried out in more than 4 weeks (effect size = 0.535). Thus the Hawthorne effect influences the effectiveness of the use of mathematical software on students’ mathematical abilities. This fact is considered by education practitioners in using mathematical software in the future.