Algorithm Optimizer in GA-LSTM for Stock Price Forecasting Yohanes Leonardus Sukestiyarno, Dian Tri Wiyanti, Lathifatul Azizah, Wahyu Widada Contemporary Mathematics Singapore, 2024 Fluctuating stock prices make it difficult for investors to see investment opportunities. One tool that can help investors overcome this is represented by forecasting techniques. Long Short-Term Memory (LSTM) is one of deep learning methods used in forecasting time series. The training and success of deep learning is strongly influenced by the selection of hyperparameters. This research uses a hybrid method between the Genetic Algorithm (GA) and LSTM to find a suitable model for predicting stock prices. GA is used in optimizing the architecture such as the number of epochs, window size, and the number of LSTM units in the hidden layer. Tuning optimizer is also carried out using several optimizers to achieve the best value. From method that has been applied, it shows that the method has a good level of accuracy with MAPE values below 10% in every optimizer used. The error rate generated is quite low, in case-1 with a minimum RMSE value of 93.03 and 94.40, & in case-2 with an RMSE value of 104.99 and 150.06 during training and testing. A fairly stable and small value is generated by setting it using the Adam Optimizer.
Learning trajectory of non-Euclidean geometry through ethnomathematics learning approaches to improve spatial ability Yohanes Leonardus Sukestiyarno, Khathibul Umam Zaid Nugroho, Sugiman Sugiman, Budi Waluya Eurasia Journal of Mathematics Science and Technology Education, 2023 Non-Euclidean geometry is an abstract subject and difficult to learn, but mandatory for students. The ethnomathematics approach as a learning approach to improve students’ spatial abilities. The aim of this research is to discover new elements of the spatial abilities of non-Euclidean geometry; determine the relationship between spatial abilities for Euclid, Lobachevsky, and Riemann geometry. This study used the micro genetic method with a 2×2 factorial experimental research design. The sample of this research is 100 students of mathematics education. There are three valid and reliable research instruments through expert trials and field trials. Data collection was carried out in two ways, namely tests and observations. Quantitative data were analyzed through ANCOVA, and observational data were analyzed through the percentage of implementation of the learning trajectory stages. The result is that the spatial ability of students who are given the ethnomathematics learning approach is higher than students who are given the conventional learning approach for Lobachevsky geometry material after controlling for the effect of Euclidean geometry spatial ability. Also, the same thing happened for the spatial abilities of Riemann geometry students. The learning trajectory is conveying learning objectives (learning objective); providing ethnomathematics-based visual problems; students do exploration; students make conclusions and summaries of exploration results; and ends with students sharing conclusions/summaries about concepts and principles in geometric systems. It was concluded that learning non-Euclid geometry through learning paths with an ethnomathematics approach had a positive impact on increasing students’ spatial abilities.
Augmented Reality assisted by GeoGebra 3-D for geometry learning W. Widada, D. Herawaty, K. U. Z. Nugroho, A. Anggoro Journal of Physics Conference Series, 2021 Geometry becomes a difficult subject for students. The abstract object was one of the factors. Therefore, more concrete learning media are needed. One of them was augmented reality assisted by GeoGebra. The purpose of this study was to determine the ability to understand the geometrical concepts of high school students through augmented reality learning assisted by GeoGebra. Treatment was given to students through learning using GeoGebra-assisted augmented reality. This was a quasi-experimental study with a pre-test post-test control group design. This research instrument was a test of the ability to understand the concept of geometry. The test was used to measure students’ initial abilities, and this was referred to as a covariate. Also, to measure the ability to understand concepts after students follow augmented reality learning assisted by GeoGebra. Data were analyzed by covariate analysis (ANCOVA). The results of this study were F = Fo (A) = 9,150 with p-value = 0,000 <0,005. That means, there are differences in the ability to understand the concept of geometry between those taught with augmented reality which is assisted by GeoGebra and conventional learning. Other results show that t = 6.723 with p-value = 0.000 <0.05. This shows that the ability to understand the geometry concepts of students taught with augmented reality assisted by GeoGebra was higher than students who were taught conventionally after controlling for covariates. The conclusion was that the ability to understand the concepts of geometry through GeoGebra-assisted augmented reality learning was better than students taught with ordinary learning.
The ability to solve mathematical problems through realistic mathematics learning based on ethnomathematics A. Lubis, W. Widada, D. Herawaty, K. U. Z. Nugroho, A. Anggoro Journal of Physics Conference Series, 2021 Problem-solving is one of the goals of mathematics learning. Ethnomimetic-based realistic mathematics learning is learning with starting-point contextual problems that are close to students’ minds. This study aims to determine the effect of ethnomathematics-oriented realistic mathematics learning on problem-solving abilities. That is a type of quasi-experimental research. The study design was a non-equivalent control group. The population is SMA N 2 Kota Bengkulu in 2019. The sample of this study was 68 students from Class X MIPA A and X MIPA D. The research instrument was a test of problem-solving skills. Data were collected through tests and analysed by covariate analysis. The results of this study are that realistic mathematics learning oriented to ethnomathematics has a positive effect on the ability to solve. The conclusion is that realistic mathematics learning with ethnomathematics orientation can improve mathematical problem-solving skills for secondary school students. We suggest that mathematics teachers can develop realistic mathematics learning tools with ethnomathematics as a starting point for learning.
The exploration of the elementary geometry concepts based on Tabot culture in Bengkulu N. Agusdianita, W. Widada, N. Afriani, H. Herawati, D. Herawaty, K. U. Z. Nugroho Journal of Physics Conference Series, 2021 Geometry’s direct objects were abstract. It was a learning material that was difficult for elementary students. Therefore, learning was needed close to the minds and daily lives of students. One of them was “Tabot” Culture. That was the ethnomatematics approach. The purpose of this research was to explore elementary geometry concepts based on Tabot Culture. We apply an explorative-qualitative approach. The subjects of this study were the makers of the Tabot, elementary students, and elementary mathematics teachers. This was a needs analysis. Activities were carried out through direct observation, documentation, in-depth interviews and focus group discussions. The research instruments were anecdotal direct observation sheets, and interview guides. Data were analysed qualitatively. The results of the study found that the culture of Tabot provides reinforcement of student character that was obeying the principle, thinking logically, critically, working hard, curiosity, independence, confidence. The geometrical concepts that exist in the Tabot culture were the cube, the beam, the pyramid, the prism, the sphere and its elements. Also, understanding of two-dimensional figure. We conclude that Bengkulu Tabot culture can be used as a starting-point for learning the achievement of geometrical concepts and strengthening student character.
The genetic decomposition of students about infinite series through the ethnomathematics of Bengkulu, Indonesia W. Widada, S. Efendi, D. Herawaty, K. U. Z. Nugroho, F. R. Putri Journal of Physics Conference Series, 2020 The cognitive theory views individuals as active information processors, so that individuals were able to represent each information according to the level of knowledge they have. Student representation can be seen as its genetic decomposition. Ethnomathematics was a vehicle for unlimited series learning. The purpose of this study was to describe the genetical decomposition of students about infinite series through the Bengkulu ethnomathematics. This was the initial research from a series of development research. This stage we interviewed in depth 10 high school students in Bengkulu, Indonesia. The research instrument was the researchers themselves who were guided by interview guides about understanding concepts and the principle of infinite series. Interviews were conducted during and after Bengkulu’s ethnomathematics learning. Data were analyzed through fixed comparison techniques. The results of this study were found that students can coordinate two or more actions about convergence of sequences, but not for convergence of infinite series. Conversely, there were students who can describe a particular object about converging an infinite series but not coordinated with the processes that were built for converging sequences. Also, there were students who can coordinate the action-process related objects so that a schema of converging sequence was formed, but for infinite series only in the form of separate actions or processes. The conclusion of this study was the genetic decomposition of students in understanding the infinite series through ethnomathematics learning at the intermediate level (inter level). The student before ethnomathematics learning was at the lower level (intra and pre-intra levels).
The cognitive process of extended trans students in understanding the real number system D. Herawaty, W. Widada, Iran Sairan, Fizi Herdian, K. U. Z. Nugroho, Abdurrobbil Falaq Dwi Anggoro Journal of Physics Conference Series, 2020 There were seven levels of student schema development in learning real analysis. Extended trans was the highest cognitive level. The purpose of this study was to describe the cognitive process of students in understanding the real number system. This was the initial part of development research. We want to know the highest initial ability students have about real number systems. The subjects of this study were 12 students of Real Analysis at the Bachelor of Mathematics Education Program. Students were interviewed based on assignments. Data were analyzed using fixed comparison techniques. The results of this study were that students can build linkages between actions, processes, objects, and other schemes (performing retrieval of the previous schema) by using and selecting procedures or operations in real number systems. He was able to apply the concept of the properties of bounded set to problem solving so that a mature scheme was formed. The scheme can be used to solve related problems. Also, can build new structures based on mature schemes that they already have. The conclusion of this study was that students can interiorize, encapsulate and thematize schemes that mature into a deductive structure.
The mathematization process of students to understand the concept of vectors through learning realistic mathematics and ethnomathematics W. Widada, D. Herawaty, Yeyen Beka, R. M. Sari, Rizki Riyani, Khathibul Umam Zaid Nugroho Journal of Physics Conference Series, 2020 The concept of vector was one of concepts that was difficult for students to understand. Realistic mathematics learning with ethnomathematics approach makes it easy for students to learn mathematics. The purpose of this study was to describe the mathematical process of students in understanding vector concepts through learning realistic mathematics and ethnomathematics. This research was the prototype stage of development research. The subjects of this study were 38 high school students in Bengkulu. Observation sheets, anecdotes and interview guides were the instruments of this research. Data was collected during the realistic mathematics learning process using the ethnomathematics approach. Data was analyzed qualitatively. The results of this study were the mathematical process of students in understanding the concept of vector by using selfie culture. Camera drones can stop in space. This was one of the multiplication properties of two perpendicular vectors. Multiplication of points was zero. The conclusion of this study was that the mathematical process of students using realistic selfie culture can achieve the multiplication of two vectors which form right angles.
Understanding the number concepts through learning Connected Mathematics (CM): A local cultural approach Desi Andriani, W. Widada, D. Herawaty, H. Ardy, K. U. Z. Nugroho, N. Ma’rifah, D. Anggreni, A. Anggoro Universal Journal of Educational Research, 2020 Mathematics becomes an important subject in elementary school. Numbers are one part of school mathematics. Learning that links between concepts and what is close to students' minds makes it easy for students in the process of reaching concepts. This is CM based on local culture. This research used a 2x2 factorial design. The population is all elementary school students from the "Integrated Islamic Foundation" in Bengkulu City. Samples were taken by using an intact group technique. The total sample is 60 students. With the local culture-based CM learning for experimental class and conventional learning for control class, the research instrument is a test of the ability to understand the concept of numbers. It is a valid and reliable instrument. The data was analyzed using the ANCOVA statistical test. The results of this study are Fo (A) = 9.7289 with, df = (1, 57) and p-value = 0.090 <0.05, which means Ho is rejected. It is showed that there is a linear effect of the covariate (initial ability) to understand the concept between the students who follow the learning by using CM with a local cultural approach. Fo (B) = 4.8096, df (1, 57) and p-value = 0.016 <0.05. In this case, Ho was also rejected. Thus, it can be inferred that there is the influence of CM learning with a local cultural approach on the ability to understand number concepts. It can be concluded that the average score and comprehension of the number concept for students who were taught by using CM learning was higher than the students who were taught with conventional learning models. Finally, the mean score for students' ability to understand the number concepts among the students who were given local culture-based materials was higher than the students who were given the materials which are not based on local culture.
The competence of teachers based on academic qualification and gender M. Marjon, K. U. Z. Nugroho Journal of Physics Conference Series, 2019 The study aims to determine the competency map of Bengkulu City Junior High School (SMP) teachers based on age, class and gender. This research is the research of Junior High School teachers in Bengkulu City. This study is a survey with a sample of 157 mathematics teachers at SMP Bengkulu City Year 2015.The result of this study is the level of Graduation for Bengkulu Junior High School teachers only 64.97% graduated, and 35.03% did not pass, it shows that the completeness of SMP Teacher competence in Bengkulu City has not been reached. The percentage of UKG graduation rate in 2015 for junior high school teachers in Bengkulu City when reviewed by sex is that the junior high school teacher in Bengkulu city has male gender as many as 63.83%, and female is 65.45%. The average score of SMP Teacher competence in Bengkulu City based on academic qualification (≤D3, D4 / S1 and S2) is 52.51; 58.84 and 69.21. This indicates that the average score of competence of teachers who have academic qualification of S2 has the highest score and the teacher who has the lowest D3 qualified has the lowest score, even under the passing grade that must be achieved.
The ability to solve mathematical problems through youtube based ethnomathematics learning International Journal of Scientific and Technology Research, 2019
