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The coating of nickel (Ni) or Ni-alloy is one of the important metals for engineering applications. These materials have properties such as good corrosion resistance, ferromagnetic, good heat conduction. A few decades, numerous researches on electrodeposition of Ni from Watts's electrolyte solution have been reported. Therefore, in this research, Ni coated on polycrystalline copper (Cu) alloy substrates were prepared with various current density 3 mA/cm², 10 mA/cm², and 25 mA/cm² in watts solution to view more details about the effect of current density on the structure, morphology, and corrosion resistance of these films. The crystal structure, electrochemical behavior, and surface morphology were analyzed using X-Ray Diffraction (XRD), Potentiostat, and Scanning Electron Microscope (SEM) respectively. The difference in current densities affects crystallography parameters, electrochemical behaviors, and surface morphology of Ni layers. There are three major peaks exhibits as (111), (002), and (022) with cubic FCC crystal system and Fm-3m space group. The crystallite size of Ni film increases as the current density rise higher value. The highest corrosion rate is seen on the Ni-25 sample, and it is probably due to larger crystallite size and smaller polarization resistance. Increasing the current density has a significant influence on the reduction peak of Ni layers. As the current density increase, the peaks decrease. All the Ni layers display active-passive-transpassive behavior in 3.5% NaCl. All the Ni film produced shows electrochemically irreversible because the distance between oxidation and reduction peaks is more than 57 mV. [ABSTRACT FROM AUTHOR]

This study aims to determine the effect of the STEM Project Learning Model on the ability to make science encyclopedias in elementary school teacher candidates. This research was conducted on elementary school teacher education students at the University of Halu Oleo, Kendari. This science encyclopedia consists of an introduction, concept development, real-life application, concept reinforcement, and evaluation. The encyclopedia of science is very useful for prospective elementary school teachers as a means of competency development and to meet the challenges of globalization so that they can become professional teachers. The results obtained indicate that the use of the STEM Project Learning Model can affect the ability of prospective elementary school teachers to create a science encyclopedia. [ABSTRACT FROM AUTHOR]

The M 8.3 Sumba Earthquake occurred on August 19, 1977. Data from the National Center for Earthquake Studies (PuSGeN, 2017) shows that the Sumba Megathrust Segment has a potential earthquake with a maximum magnitude of 8.9. Sumba Island is one of the tourism sites for domestic and foreign tourists, so it needs disaster mitigation. As the first mitigation step, the purpose of this study is to identify the tsunami-prone areas. The research method uses a tsunami numerical simulation. For scenario using the maximum magnitude and the focal mechanism in the 1977 Sumba Earthquake. The outputs from tsunami simulation are the values of the Maximum Tsunami Height (MTH). Then MTH values are mapped to the level of tsunami hazard warning along the Coast of Sumba Island. The results showed that the tsunami hazard occurs along the Coast of Sumba Island. The tsunami's impact in the southern part of Sumba is more dangerous than the northern part of Sumba. The mayor's warning level occurs along the southern coast of Sumba from West Sumba to East Sumba. [ABSTRACT FROM AUTHOR]

Electromagnetic waves are waves that propagate without the need of medium. One of the equations to describe the phenomenon of electromagnetic wave scattering problems is the Helmholtz equation. There are difficulties in solving the Helmholtz equation numerically, two of which that the solution form is highly oscillatory and the numerical solution of the high-frequency cases has low accuracy, which is called "pollution effects". Due to the limitation of memory and CPU size in a digital computer, simulating this problem with a large size of computational points is impossible. Besides, solving the linear system of the Helmholtz equation is quite challenging. It is difficult to find an efficient iterative solver that can converge with only a few iterations. This research presents a numerical scheme to minimize the "pollution effect" that appear in the numerical solution of the Helmholtz equation. The numerical scheme gives better accuracy than the standard scheme of the finite element. Moreover, we solve the linear system by using an algebraic multigrid as a preconditioner in a main iteration routine, which is based on a preconditioned variant of generalized conjugate residual (GCR) methods. This solver can give a better performance regarding its number of iteration and the time cost. [ABSTRACT FROM AUTHOR]

This article is a result of reference analysis about how to use GeoGebra software in learning physics. Specifically in this paper explained how to use GeoGebra to teach the concept of particle kinematics in 1D and 2D. The discussion is focused on straight motion (1D) and parabolic motion (2D) concepts. Each discussion is accompanied by equations of straight motion or parabolic motion and also displays the results of making graphs with GeoGebra to make it easier for readers to understand. The results of the analysis can be concluded that the use of GeoGebra software can be easily used by students if they have been equipped with mathematical concepts and knowledge about graphics. The inference from the results of this analysis is that it is time for teachers to learn and be able to use computer-based and applicative software. [ABSTRACT FROM AUTHOR]

Students always feel about self-awareness on their cognitive functions as a part of metacognitive beliefs. This aspect is being important to support learning process consistently. The aim of this case study was assessed students' metacognitive beliefs during learning science. The Metacognition Questionnaire-30 (MCQ-30) which is being instrument for this study, consists of five subscales namely positive beliefs about worry, negative beliefs about uncontrollability and danger of worry, cognitive confidence, need to control thoughts, and cognitive self-consciousness has been developed originally by Wells and Cartwright-Hatton (2004). The questionnaire (30 items) which rated on a 4-point Likert scale was administered to 102 students from science education study program at public university in Bandung, Indonesia. This research subject come outs from all students in one study program for all batches. Rasch Model shows that Person Reliability is 0.71 and Item Reliability is 0.98, therefore the MCQ-30 fitted to use for university students. Results describe that the highest response is students trust their memory while the lowest response is they are not going to punish themselves if they are not controling their thoughts. Lastly, how to manage the students' memory during learning science is to be implication for further research. [ABSTRACT FROM AUTHOR]

Geometry is one of the mathematical sciences that study point, line, 2D shapes, 3D shapes, and their properties and parts. It shows that how important geometry to be learnt by students. But in reality, students consider geometry to be the most difficult material to understand in mathematics subject because geometric objects are abstract. This research method is a descriptive study, with the aim of the study is to find out the number of percentage and the level of students' mistakes using Newman's Error Analysis on mathematical communication ability in three-dimensional shapes of geometry: cube and cuboid. The subjects used in this study were students of Pre University students (class entry 2018) in STKIP Surya as many as 9 students coming from Lani Jaya Regency, Papua Province. The instrument used was type description items, as many as 5 numbers about mathematical communication ability. In giving a score in student work, researcher focus on the results of student answers that are wrong (error), 1 score for a wrong answer and 0 for a right. The analysis of the errors uses five errors according to Newman's Error Analysis, namely (1) reading error; (2) comprehension error; (3) transformation error; (4) process skill errors; and (5) encoding error. Here are the results that have been obtained based on five proficiency level errors, namely reading errors with a percentage of 37.78%, comprehension error with a percentage of 86.67%, transformation error with a percentage of 82.22%, process skill error with a percentage of 71.11 %, and encod- ing error with a percentage of 80%. Based on the results obtained in this study, the researchers conclude that the large percentage of errors made by Pre University students in STKIP Surya Tangerang at the stage of comprehension error, transformation error, and encoding are categorized very high, then at the stage of process skills error can be categorized high, while at the reading error stage can be categorized low. [ABSTRACT FROM AUTHOR]

In a recent paper, we argued in favor of the Gross-Pitaevskii model as a complete depiction of both the close planetary system and winding worlds, particularly considering the idea of chirality and vortices in universes. In this paper, we apply the new model based on Bogoliubov-de Gennes equation correspondence with Bohr-Sommerfeld quantization rules. Then we put forth an argument that from Bohr-Sommerfeld quantization rules, we can come up with a model of quantized orbits of planets in our solar system, be it for inner planets and also for Jovian planets. In effect, we also tried to explain Sedna's orbit in the same scheme. [ABSTRACT FROM AUTHOR]

The dangers of forest fires in Indonesia are now seen as a regional and even global disaster. This may result in smokes haze which can destabilize security in all sectors of the economy, including aviation. This research aims to detect haze using the brightness temperature of MODIS' infrared channel. As known that the MODIS Aqua and Terra satellites are equipped by especially the infrared channel of wavelengths of 10.780 – 11.280 µ m (channel 31) and 11.770 – 12.270 µ m (channel 32) as well as of wavelength of 3.929 – 3.989 µ m (channel 22) and 4.020 – 4.080 µ m (channel 23) which could be utilized to estimate the brightness temperature and to understand how the surface temperature was occurred and distributed. In this case, the brightness temperature was measured using the multi-channel method. However, the radiance value of the NASA's website data that is different from the brightness temperature of the LAPAN's website data was converted by applying the Planck formula. The conclusions of the research show that there was a similarity spatial performance (digital imagery) of haze detection between both data sources, especially the data of 15 – 16 July 2018 and 6 – 7 August 2019. The spatial results of channels 22 – 23 described a lot of contact between the values of basic surface, fog, sandstorm, and smoke values. Meanwhile, the spatial result of channels 31 and 32 identified the majority contact of fog and cloud. [ABSTRACT FROM AUTHOR]

Transition Metal Oxide (TMO) has emerged recently as a promising material for Oxygen Evolution Reaction (OER), especially for Perovskite Oxide due to its catalytic activity and abundance in nature. In this work, Barium Titanate Oxygen-deficiency (BTO) (BaTiO3-x) has been synthesized with a sol-gel method followed by a variation of sintering period to discover an effect to the formation of oxygen vacancies related to the optical bandgap. This review is started to proof the formation of barium titanate oxygen-deficiency with TGA and DSC to understand the thermal habit of BTO formation, then using FTIR and Raman to understand any remain organic compound and any kind of configuration BTO formed, and UV-Vis to understand the bandgap of BTO as a function to reduce the activation energy. The results showed that by varying the sintering period (0, 2, 4, and 8 hours) has made a significant difference to the formed BTO and also the optical bandgap. [ABSTRACT FROM AUTHOR]

This research was aimed to analyze the comparison of NOAA-11/AVHRR LST Algorithm and MODIS LST data. The LST Algorithm of AVHRR/NOAA was developed by Rustana using a split-window method of thermal infrared channels 4 and 5 which was validated using Australian LST ground measurement. The algorithm will be applied to the MODIS thermal infrared of channels 31 and 32 data in order to determine the LST. This LST measurement will be comparatively analyzed with direct LST measurement of MODIS using the Python and Origin Pro software. The result indicated that the LST algorithm measurement of the first and second-order was linearly the best fit with the LST measurement of MODIS data using Python and Origin Pro Software with an accuracy of about 1.65 °C and 1.29 °C. It can be concluded that the developed LST Algorithm of AVHRR/NOAA can be applied to measure LST in Indonesia. [ABSTRACT FROM AUTHOR]

Drought analysis is very important as an impact of climate change, especially in mitigating and adapting to hydrometeorological disasters. Palmer Drought Severity Index (PDSI) classification is used to determine wet and dry season when natural phenomena occur such as the El-Nino Southern Oscillation (ENSO) event. The drought index is a meteorological drought by measuring the supply of humidity using the water balance equation of calculated using precipitation and potential evapotranspiration. The Palmer method is used to identify wet and dry season. Dry categories occur in El-Nino episodes, and wet categories occur in La-Nina episodes. We use TerraClimate data on Java monthly from 2000 to 2019 (20 years) spatial resolution 4km. The analysis of the suitability of rainfall characteristic time series and frequency distribution on the island of Java shows that the PDSI technic more clear significantly, especially during the wet months in 2010 and 2016, and the dry months 2006 and 2015. In the La-Nina case, the PDSI value approached 8 was extreme wet or La-Nina strong in 2010 and 2016 is La-Nina weak, it means wet category in episodes of La-Nina more rainfall, whereas in the El-Nino strong in 2006 and 2015 is El-Nino weak in this case that PDSI value approached -5, it means dry category in episodes of El-Nino less rainfall. [ABSTRACT FROM AUTHOR]

The coastal zone is a strategic area in terms of its geographical position and natural resources and is also an area with a high vulnerability to climate change. The rise in sea level and wave intensity causes damage to coastal zones. This research is focused on analyzing abrasion and accretion due to climate change along the Yogyakarta coast using 24 scenes of Landsat 4 and 7 data from 2000 to 2018. Landsat Tier 1 data (corrected and suitable for time series analysis) is accessed via Google Earth Engine, then delineated the shoreline. The analysis was carried out based on seasonality, considering that each season shows a different temperature and wind direction trend. The results showed that Srandakan and Galur were the districts that experienced the worst abrasion in Yogyakarta. From 2001 - 2018, Galur District experienced abrasion, reaching more than 350.000 square meters for the June-July-August period, while Srandakan District reached more than 270.0 square meters. The magnitude of abrasion in the two sub-districts is due to the position of the most perpendicular to the average wind direction. It has a geological structure that is more vulnerable than other coastal zones in Yogyakarta. [ABSTRACT FROM AUTHOR]

Water availability determines the survival of all creatures. Extreme conditions that often arise related to climate change are drought and flood. Impacts of climate change and extreme weather on the water balance in Java have been analyzed using TerraClimate data from January 1958 to December 2019 with monthly temporal resolution and spatial resolution of 1/24 ° or about 4 km. The data showed that climate change has led to an increasing trend of rainfall in Java by 1,472 mm per year. The data also showed that climate change has strengthened the intensity and frequency of extreme events as seen from the dry extreme events in 1997 and 2015 (El Niño) and wet extreme events in 2010 and 2016 (La Niña). This extreme event has had major implications for the water balance in Java. The high rainfall in 2010 and 2016 resulted in the saturation of soil moisture throughout the year, increased runoff level twice from its normal value, and floods in several areas in Java. On the other hand,when the rainfall was very low in 2015, there was a drought. Extreme wet conditions that occurred in the period of 2010 and 2016 have caused a high runoff on Java Island, where the higher rainfall that occurred in 2016 has smaller implications for the runoff than the 2010 rainfall. It was caused by higher rates of evapotranspiration and infiltration experienced in 2016. El Niño happened in 2015 where a long drought occurred and caused conditions of soil moisture to be very low reaching less than 50 mm while the average spatial runoff rate was close to zero. This is the condition of the water balance at the beginning of 2016. The rainfall that occurred in 2016 is mostly used for filling groundwater, depression, and surface water. [ABSTRACT FROM AUTHOR]

Microcantilever is a device of MEMS (microelectro-mechanical system) which can be used as a bio-chemical sensor, such as to determine the characteristics of chemical liquids. In this work, an investigation of evaporation rate of chemical liquids, i.e., ethanol, methanol, and propanol, was carried out using resonant frequency change of vibrated microcantilever. We used two types of microcantilever, namely uncoated-microcantilever (reference) and ZnO-coated microcantilever. A growth of ZnO nanorods on microcantilever was carried out by hydrothermal method through 2 stages, i.e., a coating of seed (seeding) and growth of ZnO rods. The seed layer was deposited by dip-coating method from the solution of zinc nitrate tetrahydrate (ZNT) and dietanolamine (DEA) in ethanol. ZnO nanorods were then grown by hydrothermal method from the solution of zinc nitrate tetrahydrate (ZNT) and hexamethylenetetramine (HMTA) in demineralized water at 80°C for 2 hours. The experimental results show that, the resonant frequency of uncoated-microcantilever before dropping ethanol was measured of 36.80 kHz. After dropping ethanol on the microcantilever, the resonant frequency raised to 36.84 kHz. From the resonant frequency data, the evaporation rate of ethanol can be calculated to be 0.150 picogram/minute. Moreover, the evaporation rate of methanol and propanol was obtained 0.149 picogram/minute and 0.149 picogram/minute, respectively. For ZnO-coated microcantilever, the resonant frequencies before and after dropping propanol reveal the value of 13.98 kHz and 12.33 kHz, respectively. However, the resonant frequency did not return to the initial value after ethanol dropping, indicating that the propanol molecule reacts with the ZnO surface and remains on the surface. [ABSTRACT FROM AUTHOR]

The microcantilever sensor is one of the most generally studied and learned sensors currently on the fields of chemistry, biology, health and environmental factors such as temperature, humidity, sound and pressure. This is because the microcantilever sensor has a high sensitivity to the attogram scale (10−18). The Q factor of the microcantilever sensor illustrates the sensitivity of the sensor. This research was carried out in 48% and 55% humidity variations with the chamber opened and closed. The results showed that the higher of humidity, degrades the Q factor in the microcantilever sensor. The average value of the Q factor when chamber was opened at 48% humidity was 285.2 and 240.9 at 55%. When the chamber is closed at the 48% of humidity has an average Q factor in 266.7 and 243.3 at 55%. This is due to water molecules attached to the microcantilever sensor when humidity is high causes a decrease of the resonant frequency in the microcantilever sensor where the Q factor has an equal value to the resonance frequency. [ABSTRACT FROM AUTHOR]

Scientific argumentation skill is very important to be mastered by students. It allows students to analyze, to make decisions based on the result of thinking, and to apply science in everyday life. This study aims to analyze and describe the characteristics of students' scientific argumentative skills in the Primary Educational Teacher Department based on the results of computational thinking tests about motion system material. This is exploratory research with quantitative and qualitative data analysis to understand the characteristics of students' answers in proposing scientific arguments and computational thinking. The participants of this study were second-year students in class-D of Primary Educational Teacher Department in the even semester of class 2019/2020. They were taken by a random sampling technique. The applied instrument was a written test instrument with a subjective form entailed by indicators of computational thinking skills. This applied instrument was to identify and analyze the characteristics of students' scientific argumentative skills. The results were then analyzed descriptively with Toulmin's Argumentation Pattern (TAP). The results showed that the characteristics of scientific argumentation skill of Primary Educational Teacher Department students were 4% of students at level 1, 8% of students at level 2, 15% of students at level 3, 31% of students at level 4, and 43% of students at level 5. On another hand, the results of computational skills showed that the students' thinking was high in the analyzing stage, elaborating, providing hypotheses, and finding patterns of problems. The results of this analysis indicated that the characteristics of scientific argumentation skills and computational thinking skills of Primary Educational Teacher Department students need to be developed optimally. [ABSTRACT FROM AUTHOR]

This study aims to develop an Electronic Dictionary of Indonesian Sign Systems (ED-ISS) based on Raspberry Pi. The ED-ISS consists of input modules (RFID card, keyboard, and microphone); a raspberry pi as process module; and LCD display as well as audio as output modules. ED-ISS visualizes words into sign language (hand motion) that can be understood by deaf students. The results of the study reveal that the content validity of the ED-ISS is 89.7% (according to learning material experts), while the construct validity is 87.95% (according to media experts). Moreover, deaf students value the ED-ISS as 87.90% effective to translate words into sign language (hand motion). [ABSTRACT FROM AUTHOR]

This study focuses on students' exploration of work and energy using PhET interactive simulation and involving 36 students of high school in physics class. Students were working in small groups to explore virtual phenomena using PhET - the ramp and energy skate park. The worksheets were created by teacher to guide students in the inquiry-based exploration of scientific phenomena. During the lesson, students input the data, controlled related variables, and interpreted the graphs. At the end of the lesson, some questions were administrated by the teacher to focus on students' interpretation of graphs and pictures related to the concept of work and energy. It was found that the students were interested in PhET interactive simulation and actively ask questions during the lesson. Thus, students' interpretation of graph is better than before. The research concluded that students can 1) analyze the relationship between forces and changes in kinetic energy in objects moving in horizontal field, 2) analyze the relationship between forces and potential energy and potential energy changes in objects moving in an inclined, 3) Analyzing the relationship between non-conservative forces with mechanical energy, 4) evaluating the suitability of relationship the graphs/images between the position of objects with kinetic. [ABSTRACT FROM AUTHOR]

This study aims to describe the use of Google Classroom as ICT literacy to improve the collaboration skills of physics students in the industrial revolution 4.0. This research was conducted at the Musamus University, Merauke, by taking physics education students as research samples. The research method used in this study is a qualitative descriptive method using questionnaires as research instruments. The instrument used was validated using product-moment, and the reliability was using KR-20. The results showed the use of the Google Classroom enabled learners to add insight into technology and communication with a score of 90%. This means that physics education students already have excellent ICT literacy skills. Students work productively, show respect, compromise, and take responsibility as a characteristic of collaborative skills in the industrial revolution 4.0 in collaborating with their friends and lecturer through Google Classroom with a score of 79%. This means that student collaboration skills are very good. Overall, the average score is 84,5%, so it can be interpreted that Google Classroom as ICT literacy has a significant influence in shaping student collaboration skills. Thus, it can be concluded that the use of Google Classroom as ICT literacy can improve physics students' collaboration skills in the industrial revolution 4.0. [ABSTRACT FROM AUTHOR]

Ambon earthquake (Mw 6.5) occurred on September 26, 2019, has an almost identical location with the earthquake which occurred on September 09, 1932. Accordingly, the authors considered that the return period (Tr) of the earthquake takes 87 years. Along the interseismic period, there were stress accumulation processes related to the earthquake (Mw 6.5). Based on the passing through of scaling law relation of the earthquake, the authors calculated the fault length (L), fault width (W), and displacement rate (d), as well as the seismic moment (M0), are about 19 km, 15 km, 46-47 cm, and 6.185x1025 dyne-cm, respectively. By using the values off M0, L, W, and Tr, the authors have estimated other parameters, such as the static stress drop (9.21 bars), slip rate (8-9 mm/y), strain rate 6x10-15/s, and static stress Coulomb (more than 1 Pa). Two earthquakes that triggered the tsunami occurred on January 29, 2004 (Mw 6.7) and March 14, 2006 (Mw 6.7) in a similar tectonic regime and adjacent to the Ambon earthquake occurred on September 26, 2019. By using a passing through physical basic approach, the authors have estimated the return period (Tr) of both earthquakes (i.e. about 93 years and 113 years), respectively. [ABSTRACT FROM AUTHOR]

Considerable research carried out in Indonesia heavily focused on how self-efficacy is related to other variables. However, there is no study devoted to developing and validating scale measuring students' self-efficacy in mathematics learning. Therefore, the aim of the present study was to examine the validity and reliability of the Indonesian version of the Sources of Mathematics Self-Efficacy Scale. Using a cross-sectional survey with a convenience sampling, a total of 978 high school students (557 were girls and 421 were boys) from five different schools in three urban cities in Indonesia participated in this study. Based on the result of Confirmatory Factor Analysis, it was found that the four-dimensional model was well fitted. The value of goodness of fit index (GFI) of the model was χ^2 (df) = 546.08 (246), the root mean square error of approximation (RMSEA)=.07, the normed fit index (NFI)=.90, and the comparative fit index (CFI)=.92. Internal Consistency was examined through calculating Cronbach's alpha and corrected-total item correlation coefficient. The values of Cronbach's alpha for the factors ranged between 0.754 and 0.909. In addition, the corrected-total item correlation coefficients indicated a favorable level of correlation. Overall findings showed that the scale had acceptable validity and reliability score and it might be applied to identify Indonesian students' sources of mathematics self-efficacy. [ABSTRACT FROM AUTHOR]

The rapid growth of technology encourages the development in the learning activity. The situation which initially can happened only in a class, now can be visualized in a learning media. The technology facilitates the visualization and the complexity of a learning media. The use of an interactive learning media highly effective in enchancing students engagement in learning process. Realistic Mathematics Education (RME) emphasizes the mathematization process which can be best learned through students activity. The principles of RME can be manifested in an interactive learning media. Hence, by combining the principles of RME and the use of technology, an interactive learning media was developed. The method used in this research is research and development which consists of three stages: preliminary analysis, product development, and evaluating the product. The preliminary analysis showed the need to develop an interactive learning media with realistic approach. In the product development stage, the content outline, storyboard, and flowchart of the media were made. The products' validation and evaluation process followed the Dick&Carey model which require students and teachers in individual and group testing. The average score of the validation process is 90.11% which means that the interactive learning media product is classified as very good and is suitable to be used in junior high school. [ABSTRACT FROM AUTHOR]

Professional teachers must have good Pedagogical Content Knowledge (PCK). The rapid development of technology requires teachers to be able to integrate technology into their PCK, which is described by Technological Pedagogical and Content Knowledge (TPACK). TPACK is a framework that can provide new directions for teachers in solving problems related to technology integration in learning. The TPE program that is being pursued by the government is expected to produce professional teachers who have high competence. The TPE curriculum refers to the principle of an activity-based curriculum that is implemented through the TPACK concept. This study aims to determine the TPACK of TPE students in positions at Syiah Kuala University. This research uses Mixed-Method with sequential explanatory design. Data collected through questionnaires, lesson plans, learning observations, and interviews. The results of this study indicate that the TPE Students' TPACK ability in a position is in the Poor category. TPE students admitted to having good TPACK knowledge, and they can also translate this knowledge into a lesson plan, but it was not carried out well in the learning process. The obstacle for TPE students in implementing TPACK in class was the inadequate availability of facilities at schools. Then the technical knowledge regarding the use of technology was still not owned by students. Students' knowledge in choosing technology that suits mathematics material was also lacking. [ABSTRACT FROM AUTHOR]

Noticing is the ability needed to handle learning situations that occur simultaneously, accommodate student needs, and engage students during learning. In this study, noticing is teachers' ability to identify important situations or events, interpret them, and make connections with the principles of Realistic Mathematics Education (RME). The existing noticing questionnaire using general learning principles is related to more specific principles, such as RME. This study aims to determine the content validity of the noticing questionnaire based on RME principles. This study used the Plomp and Nieveen development method, focusing on the preliminary research and prototyping phase. The instrument in this study was a validation sheet. Data sources were two experts of RME and the expert of teachers' noticing. It is concluded that the noticing questionnaire based on the RME principles has fulfilled the content validity criteria so that can be used to notice RME-based learning videos. [ABSTRACT FROM AUTHOR]

Critical thinking is one of the most popular 21st-century learning skills. Students in Indonesia in the field of Mathematics is still a lack of ability of students in Indonesia to work on exercises with critical thinking domains. The purpose of this study is to develop learning materials that can help train students' critical thinking skills. The research method used is the research development of Derek Rowntree. The study employed data collection by tests of critical thinking skills in Mathematics subjects for grade IV elementary school. The research was conducted at Karawaci Baru 3 elementary school, Tangerang City. The pilot study has been conducted to 25 students. The results indicate the mathematical learning module model can stimulate the critical thinking skills of elementary students is looked at test results of critical thinking skills. Mathematics learning module model offered a more philosophically in stimulating critical thinking skills and demonstrated how this module model could be used to Mathematics subject. The next research recommendation is that it is necessary to conduct an experiment on the results of the module design principles to review the effectiveness, efficiency, and practicality to stimulate the critical thinking skills of fourth-grade elementary school students. [ABSTRACT FROM AUTHOR]

Abstract. Based on the socio-economic survey conducted by the Central Bureau of Statistics (2018), there are 3.29 million people or 1.93% of Indonesians who bear illiteracy (read, write, and count). Their average is 45 years old and above, living in rural areas, and most women. They need to be taught to read, write, and count. This study focuses on the analysis of the difficulty of learning to count. The research method used is a case study at PKBM Pratama in Indramayu District. The research subject is 17 learners. Data collection techniques include observations, interviews, and documentation studies, while data analysis is conducted with preliminary study stages, data collection, data reduction, data presentation, confirmation, and withdrawal of conclusions. This study found that the blind students' difficulty of learning in the PKBM Pratama were the barriers to learning concentration, quickly bored, the vision began to diminish, felt saturated, and feelings of inferiority with the community environment. Especially in counting learning, the difficulty is in understanding the counts' symbols and interpreting the measurement results between theory and practice in daily life. The research recommendation is that educators need to provide examples and simulations realistically in counting learning so that students understand more about the concept of interpretation of measurement results and count symbols in the daily life of learners. [ABSTRACT FROM AUTHOR]

Students' problem-solving skill is a process that involves thought, action, and participation in a problem. This study aimed to describe Students' mathematical problem-solving skills in PISA problems based on Newman's problem-solving steps. This study employed a qualitative descriptive approach, and the subjects were six Junior High School students aged less than 15 years selected by purposive sampling. Data collection was conducted by administering PISA problem tests and interview through G-meet. The interview data were analyzed descriptively, while the data of the test results were analyzed based on the assessment guideline of students' problem-solving skills. The results revealed that S1 solved the problems by reading, comprehension, transformation, processing skill and encoding; S2 and S3 solved the problems by reading the problems, comprehension, and transformation problems; S4 and S5 solved the problems by reading and comprehension; and S6 solved the problems just by reading problems without understanding the problems. Thus, students' problem-solving skills still unsatisfied. Based on the findings, further research investigating the factors affecting student achievement in PISA is necessary. [ABSTRACT FROM AUTHOR]

This qualitative research aims to explore parts of Masjid Agung Demak such as the Tajug, the top of the Tajug, the Soko Guru pillars, the carving of padma, and the carving of bledeg from ethnomathematics point of view. This exploration activity aims to see the mathematical elements contained in the Masjid Agung Demak. The data collection method was done by interview humanists, literature studies, and observation. Data analysis is not only based on the results of the researchers' interpretation but also based on the results of interviews conducted with humanists. The results of this study indicate that the Masjid Agung Demak contains several mathematical elements, including geometry and transformation. The geometric element is found on the Tajug which consists of three levels, the top of the Tajug, and the location of the Soko Guru pillars. The elements of transformation found in the carving of padma and bledeg. The Masjid Agung Demak is an architectural work that contains elements of mathematics. It does not only contains religious elements but accidentally contains elements of mathematics. [ABSTRACT FROM AUTHOR]

The cognitive style has an important role in determining mental activities used to perform mathematical problem-solving. This study aimed to explore students' mental activities in both field-dependent (FD) and field-independent (FI) of cognitive styles in mathematical problem-solving. The mental activities are explored in this study, including activities to understand the problems, making plans, implement, and checking the results. This research used a descriptive quantitative method. 24 subjects were enrolled in this study, consist of from the students of mathematics education of Syiah Kuala University in the academic year 2019/2020. The determination of the subjects was done using cognitive style tests. Data collection is done using mathematical problem-solving tests (MPST). Data analysis was performed by selecting and summarizing selection. We concluded that the mental activity of the cognitive style students of FI and FD restated the problem in their words, represented, selected strategies, made links to information logically, made calculations, and wrote the final answer. A deeper exploration of how the mental activity in subjects with FI and FD cognitive style and their connection to the mathematical problem-solving is needed. [ABSTRACT FROM AUTHOR]

Poverty is one of the problems that happened in DKI Jakarta. The case of poverty in DKI Jakarta can be viewed from a geographical perspective, namely because the regions in DKI Jakarta are interconnected. This study aims to determine the factors that influence spatially and non-spatially on the number of poor people in DKI Jakarta used the Poisson Regression and Spatial Autoregressive Poisson Model. Data used in this research came from Badan Pusat Statistika 2019 [1]. The parameter estimation method in this study uses the maximum likelihood method. The results showed that spatial (ρ) and non-spatial factors (β) had a significant effect with alpha 5%. Based on the null deviance, Poisson Regression Model gave a smaller value than the Spatial Autoregressive Poisson Model. [ABSTRACT FROM AUTHOR]

This study aims to analyze the impact of self-efficacy beliefs and mathematical ability on the quality of elementary school teacher tests in designing mathematical test instruments. This study uses quantitative methods, and the type of path analysis. The population in this study were all elementary school teachers in five regions of Jakarta Province, the East Jakarta, South Jakarta, North Jakarta, Central Jakarta and West Jakarta as many as 41.951 people. The sample selection was conducted using the two stage random sampling technique using the Glenn table guide, so that 100 school teachers in DKI Jakarta were determined. Analysis of the data used for research data includes: descriptive analysis, test data analysis requirements, and inferential analysis. Significance of regression testing is done by using SPSS. The results showed that; 1) self-efficacy belief directly has a positive effect on the quality of mathematics test instruments made by elementary school teachers, 2) mathematical ability directly has a positive effect on the quality of mathematics test instruments made by elementary school teachers, 3) self-efficacy beliefs directly has a positive effect on mathematical abilities. The results of this study are expected to give teachers insight into the development of mathematical test instruments for students, thus providing a reference in expanding knowledge and civilizing teachers in the design of mathematical test instruments. [ABSTRACT FROM AUTHOR]

The concept of three-dimensional sustainable development requires every country to increase economic growth by using natural resources rationally by considering environmental and social quality as a determinant of public welfare. In Indonesia, there has not been a balance between the three dimensions, for example, DKI Jakarta Province has high economic growth and Human Development Index (HDI), but Environmental Quality Index (EQI) is the worst. Whereas Papua and West Papua have good environmental quality but are not supported by good HDI. Efforts in sustainable development are planned that integrate environmental, social, and economic aspects in development strategies. Therefore, this study used the BPS Statistics-Indonesia data for analyzing the causality between economy, environment, and human development in 33 provinces of Indonesia, from 2013 to 2017. By using the simultaneous equation of the panel data (2SLS) method, it results show that there is a positive simultaneous relationship between HDI, economic growth, and environmental quality. The Variables that influence economic growth are HDI and Foreign Direct Investment (FDI). Variables that influence environmental quality are economic growth, HDI, FDI, and population, while in human development are economic growth, EQI, and poverty. Human development has a big contribution to the implementation of sustainable development in Indonesia. [ABSTRACT FROM AUTHOR]

This study aims to develop a valid, practical, and effective ethnomathematics-based student worksheet using a contextual approach to improve the mathematics learning outcomes of junior high school students. This development research applied the Dick And Carey development model consisting of ten stages of development. The trial was conducted on 16 Year 7 students from one of the Islamic junior high schools in Bireuen, Aceh, Indonesia. The instruments used in this study were the assessment sheet of student worksheets, interviews, and student questionnaires. The student worksheet was said to be valid, practical, and effective. The validation results of two mathematics education lecturers and one junior high school mathematics teacher showed that the student worksheet satisfied the 'good' criteria. Furthermore, ten students showed very positive responses, and six others expressed positive responses. The student learning outcomes test also indicated that students' scores were above the minimum criteria for mastery learning. [ABSTRACT FROM AUTHOR]

The reflective thinking process is a crucial skill to develop by students. However, the students' reflective thinking process has been far from expected. One of the reasons is because in solving mathematical problems, students are less thorough and in a rush without rechecking their work, resulting in they are unaware of any mistake they made. Besides, students' self-confidence should also be noticed as each student has a different magnitude of self-confidence. This study aims to describe students' reflective thinking process in problem-solving reviewed from the self-confidence. This research employed qualitative research, involving three out of 22 year 9 students in one of the junior high schools in Aceh Barat Daya, Indonesia. The subject selection using purposive sampling, which is the three students consisted of one student with high self-confidence, one with moderate self-confidence, and one with low self-confidence. Data collection were conducted using a self-confidence questionnaire, problem-solving test items, and interviews. The data was analyzed using descriptive qualitative method, including data reduction, data presentation, and concluding. The results showed that: (1) students with high self-confidence conducted the reflective thinking process in each step of problem-solving; (2) students with moderate self-confidence conducted the reflective thinking process in three steps of problem-solving; and (3) students with low self-confidence only conducted the reflective process in one step of problem-solving, namely understanding the problem: identifying information that is known and asked and being able to select the existing mathematical knowledge to solve problems. [ABSTRACT FROM AUTHOR]

The ability of Indonesian students to solve PISA questions on content quantity is still far from what we expected. It was proved by how low the PISA mathematic results of Indonesia are. One of the causes of how low Indonesia's PISA results is the lack of accustoming students to do PISA equivalent math problems, especially at high-level questions that require reasoning, argumentation, and creativity, which are the characteristics of PISA questions. This happened because of the availability of PISA equivalent math problems on certain content and levels are still very limited. This study aims to develop mathematical problems equivalent to level 4 of PISA's quantity content that is valid. This research is development research with the Tesmer model. Data are obtained at the time of validation which is one of the stages of research development. Valid criteria are established based on Nieveen's theory. Research data is in the form of comments, suggestions, and input from the expert reviewers of the 12 questions developed. The data source consists of four expert reviewers who are competent and experienced lecturers in the field of mathematics education and active in the Mathematics Literacy Contest. Data collection is done by using the instrument validity sheet questions. The results showed that 12 mathematical questions equivalent to PISA developed based on quantity content for level 4 met the valid criteria. These questions are in the form of essays that accommodate material in class VII, namely algebraic forms, numbers, social arithmetic, and comparisons that help in increasing students' literacy abilities. measure the practicality. This is important to do to see the readability and response of students to the language and content of the questions. [ABSTRACT FROM AUTHOR]

Problem-solving ability in derivative of functions is one of calculus learning goals in University. This study aimed to explore students' abilities to solve derivative of functions problems in rate and speed contents. This research used descriptive qualitative method. The subjects were 46 students of mathematics education at Syiah Kuala University in the second semester of the first year. The data were collected by providing a test instrument for solving derivative of functions problems to the subjects. The data were analyzed by conducting written data, interpreting, and concluding. The results of the analysis concluded that few students were able to solve the problem of derivative functions in the content of speed and rate of change. From these findings it is necessary to explore in depth the thought processes of subjects who are able and unable to solve problems related to the rate of change and speed. [ABSTRACT FROM AUTHOR]

Geogebra-assisted discovery learning model. This study aims to determine the spatial ability of students after being taught using the Geogebra-assisted discovery learning model and describe students' spatial profiles. This research employed a mixed-method approach with sequential explanatory design. Data collection was conducted through a spatial ability test administered to 30 students aged 12-13 years. Four students were then selected and interviewed, each with high, medium, and low ability. The results show that: 1) 66.67% of students have a good spatial ability after being taught using the Geogebra-assisted discovery learning model; 2) students with high and medium-ability have the same spatial ability, but medium-ability students are having difficulty in transforming and representing geometrical objects. However, the spatial knowledge of low-ability students is classified as low due to the lack of understanding of the fundamental spatial concepts. [ABSTRACT FROM AUTHOR]

This paper intends to explore how the 'counting up' strategy on an empty number line could help children overcome their mistakes in performing column subtraction problems that require regrouping. Solving subtraction problems with regrouping in column strategy is often frustrating for most children because it involves regrouping numbers in place value. In this qualitative case study, how two second graders develop their thinking while engaging in a designed instructional activity were observed and analyzed. The data collection included observations, conversational interviews, and children's written works. The results showed that the designed activity with a measurement context and an empty number line model is found to be helpful for children to develop the idea of 'counting up' in solving subtraction problems that require regrouping. The children gradually develop their counting up strategy from jumps of ones to jumps of tens to simplify the use of the empty number line model. The results help us understand that we must provide a meaningful support for children to explore various calculation strategies to improve their flexibility in solving subtraction problems. [ABSTRACT FROM AUTHOR]

Mahatma and Muchtadi-Alamsyah (2017) introduced the notion of the so-called 𝒰-extension modules which is the generalization of the concept of the extension modules. As the classic extension modules induce a long exact sequence of homologies from a given short exact sequence, there is an analogous result in the 𝒰 version in the form of an exact sequence consists of 𝒰-extension modules. It is just that such sequence has only limited number of nonzero modules while the classic one can contain infinitely many. Mahatma and Hadi (2020) proposed sufficient conditions for the sequence so it can be extended. However, it requires some tight assumptions to be hold. In this paper, we shall give another method of extending the sequence so we may avoid the dependency on the additional assumptions. [ABSTRACT FROM AUTHOR]

This research aimed to study the effect of learning by apperception learning to read the Qur'an and self-efficacy on Students' Mathematical Reasoning Ability. This research was carried out in senior high school in Kembangan District, West Jakarta. This research is in class XI in two schools, senior high school Sumpah Pemuda and Budi Murni. The method used in this study is experimental. The sample consisted of 60 students (30% of the population) taken by simple random sampling technique. The experimental group was XI class in senior high school Sumpah Pemuda or 30 students, and the control group was XI class in senior high school Budi Murni or 30 students. Data on mathematical reasoning abilities were collected using a test of ten essay questions and self-efficacy with a questionnaire consisting of 35 items. Data analysis in this study used ANOVA by first testing for normality and homogeneity. The results showed: (1) There was a significant influence on learning to read Al-Quran on students' mathematical reasoning ability in senior high school; and (2) has a considerable impact on self-efficacy on students' mathematical reasoning ability in senior high school. (3) There is no interaction effect of apperception learning to read the Qur'an and self-efficacy on students' mathematical reasoning ability. [ABSTRACT FROM AUTHOR]

Hepatitis B infection that leads to chronic stage can be life threatening to human, for prevention it is necessary to conduct treatment and vaccination. Conducting treatment and vaccination are controls variables that will be applied to the dynamic modelling of Hepatitis B using Pontryagin Minimum Principle. The present paper will describe model formulation of Hepatitis B, analyzing direction of the equilibrium, Disease Free Equilibrium (DFE) and Endemic Equilibrium (EE), which can be done by determining dimensionless number of R0 (Basic Reproduction Number). Furthermore we use Pontryagin Minimum Principle to find optimal solution of the control. The purpose of optimal control is to minimize the number of acute and chronic infected population and values (cost) of vaccination and treatment. Numerical calculations also performed to illustrate the graph. [ABSTRACT FROM AUTHOR]

This research is a quasi-experimental study with a pretest-posttest control group design. This study aims to determine the effect of peer tutoring approaches to algebraic thinking skills in primary school teacher candidates for the 2019/2020 school year at the Universitas Mataram, Indonesia. The sampling technique used in this study is cluster random sampling. This study uses a control class of 37 people where learning is carried out conventionally and an experimental class of 35 people where learning is carried out using a peer tutoring approach. The implementation of the peer tutoring approach in the experimental class uses small groups where each group has a tutor. Data analysis techniques used in this study are the analysis of covariance (ANCOVA) test, N-gain analysis, and analysis of the description of the results of the answers. The instrument used in this study is an algebraic thinking ability test in the form of essay questions. ANCOVA test results show that there is a significant effect on the algebraic thinking skills of primary school teacher candidates who are taught using the peer tutoring approach. The significance value of N-gain shows that there is an increase in the algebraic thinking skills of primary school teacher candidates who are taught using the peer tutoring approach. Other results of this study also showed that the peer tutoring approach is also able to increase social interaction and reduce students' anxiety levels about the subject matter. [ABSTRACT FROM AUTHOR]

In this paper we will discuss how to determine the distance between two convex sets in Hilbert space. This problem came from measuring the shortest distance between two cities, which consider by determining the distance between two buildings in each city. In this problem, the cities are considered as the sets and the buildings are points. Furthermore, based on this problem, it is generalized to determine the distance between two convex sets in Hilbert space that solved by optimization concept by measuring maximal distance between two parallel supporting hyperplanes that separate them. Therefore, it is given some example to understanding, such as the distance between two normed balls, ellipsoids, and linear varieties. [ABSTRACT FROM AUTHOR]

Cases of non-communicable diseases (NCD) in Indonesia tend to increase, one of which is Chronic Kidney Disease (CKD). CKD has become a global health problem because of the difficulty of treatment and expensive medical costs. CKD often refers to a a silent killer disease that develops without providing previous symptoms. One of the alternative treatments is dialysis. According to the 2018 Riskesdas, more than fifty percent of CKD patients who are undergoing dialysis is the productive age people. Ten percent to forty percent of these patients also have comorbid CKD like diabetes mellitus and hypertension. The study aims to analyze the determinant of CKD patients who undergo dialysis in Indonesia. Based on the 2018 Riskesdas, 17 percent of CKD patients undergo dialysis. Because of this condition, logistic regression modeling with an imbalance of the binary response (success and failure categories) could create a bias in the predicted probabilities. The stronger the imbalance of the response variable is, the more severe is the bias in the predicted probabilities; therefore, the firth logistic regression method is used to avoid bias. Based on the results, diabetes mellitus status, hypertension status, age, and the lack of fruits and vegetable consumption significantly affect the dialysis status of CKD patients. Thus, the community is always expected to adopt a healthy lifestyle and increase awareness of personal health by regularly checking their health at the health facility. [ABSTRACT FROM AUTHOR]

The implementation of a blended learning approach in a teacher professional development program needs to get more attention. The objective of the present study was to investigate in-service mathematics teachers' perspectives on the effectiveness of blended learning in the Teacher Professional Development Program. Sixty-four in-service mathematics teachers who completed the program in two large universities in Jakarta Province involved voluntarily in the study. By employing a cross-sectional survey, participants' responses were collected through a closed and open-ended questionnaire developed by the researcher. The data were analyzed descriptively. As a result, most participants revealed a positive perspective towards blended learning and instructors' feedback, independence, and discipline in accomplishing online assignments, readiness in technical support, and improvement of interaction. Besides, participants unpacked their points of view related to the implementation of the program. Implications of the study suggest how the findings of the study may be critical for policy, practice, and subsequent study. Finally, several recommendations are offered to improve the program. [ABSTRACT FROM AUTHOR]

This research aimed to obtain information about the influence of learning strategy and authentic assessment of students' mathematical proving abilities by controlling prerequisite concepts understanding. This study was conducted since there are still a lot of students from Mathematics or Mathematics Education Programs who find it hard to work with mathematical proving concepts. This study was a quasi-experimental study, with the dependent variable was the mathematical proving ability The independent variable (Y) was the learning strategy (A) and the authentic assessment (B), while the covariate variable was prerequisite concepts understanding (X). The data were analyzed with the two ways Analysis of Covariance (ANCOVA) to test the main effect and the interaction effect, followed by a t-test to analyze one side's main effect. From the results, it was obtained that after controlling prerequisite concept understanding, students' mathematical proving abilities were: 1) higher in the application of abductive-deductive strategy compared to the application of conventional learning; 2) higher in the application of performance assessment techniques compared to the application of portfolio assessment techniques; 3) there was an interaction effect in the application of learning strategy and authentic assessment toward students' mathematical proving abilities. This study provides an alternative for abstract mathematics lecturers to apply joint learning strategies with the assessment techniques that can develop students' Mathematical Proving Ability. [ABSTRACT FROM AUTHOR]

Hill Cipher is one of the methods used in Cryptography. In the Hill Cipher algorithm, the key square matrix must have an inverse modulo. One special matrix that definitely has an inverse is the unimodular matrix. The unimodular matrix can be used as a key in an encryption process. The purpose of this research is to show an alternative in securing digital image data. The type of cryptography used is symmetric cryptography. The algorithm presented by generating a unimodular matrix using the Logistic Map. First, to get a unimodular matrix, we use an identity matrix. The sequence of real number in (0,1) of Logistic Map then converted into integer number from 0 to 255. That number then occupies upper triangular entries of the unimodular matrix. We use the Elementary Row Operation to obtain the complete matrix as a key. Then the multiplication of matrix modulo is used as an encryption process. The unimodular matrix generated by the proposed algorithm guarantees a key in the Hill Cipher for all matrix sizes (n > 4) and only need two parameters (password 1 and password 2). We also tested the algorithm in python language on two digital images (grayscale and color) with different sizes. The results show that the encrypted images are very difficult to read by third parties. The time needed is based on password 1, that is the size of the key matrix. So, the unimodular matrix and logistic map work very well with Hill Cipher to encrypt a digital image. [ABSTRACT FROM AUTHOR]

A System of Linear Equation (SLE) that has the same number of equations as the number of variables is called the Determined SLE. But, an SLE with non-integer solutions is a problem for students. This paper can assist teachers in providing exercises on the topic of SPL with integer solutions, so students can better understand it. Moreover, a square matrix is said to be unimodular if it has a determinant value of 1 or -1. The inverse of a unimodular matrix and the product of two unimodular matrices is also unimodular. Moreover, the notion of unimodular will facilitate us in determining the solution because it does not involve fractions at all. In this article, a method is given for generating an SLE via a unimodular matrix with Python and Latex. The result is a file with pdf format that contains some Determined SLE with a unique solution in the form of integers. The conclusion is that by using the Python program, we can generate a finite Determined SLE easily with the solutions are integers. [ABSTRACT FROM AUTHOR]

For many years, mathematics has been used to solve the problem in economic and finance instead of natural science and engineering. This paper shows how accurate mathematics reads financial behavior. One of the financial areas using the mathematics approach is the bond valuation technique. Bond is one of the long term debt instruments. The finding in this research is that mathematics can be used to read the changes in the concept of a pricing model where the par value of bonds is always going to 100% at the maturity date. Theoretically, the bonds fair price is resulted by calculating the present value of future coupon interest of bonds, but not in practice, caused by the bonds investor behavior. The difference in price, resulted from both different approaches, in this paper is defined by a new mathematical concept to reflect the bonds' investor behavior. It is the aim of this research. To address the differences, we have evaluated the fair price of bonds calculation by creating new mathematics equations by combining the calculation of the present value of future coupon interest of bonds with the market concept models. The result is a new mathematical model called J-Value. To prove the eligibility of J-Value, a simulation was done. The mathematics model in this paper is found by combining the usage of a qualitative method and supported by a quantitative method. [ABSTRACT FROM AUTHOR]