Structural and System Reliability

Based on material taught at the University of California, Berkeley, this textbook offers a modern, rigorous and comprehensive treatment of the methods of structural and system reliability analysis. It covers the first- and second-order reliability methods for components and systems, simulation methods, time- and space-variant reliability, and Bayesian parameter estimation and reliability updating. It also presents more advanced, state-of-the-art topics such as finite-element reliability methods, stochastic structural dynamics, reliability-based optimal design, and Bayesian networks. A wealth of well-designed examples connect theory with practice, with simple examples demonstrating mathematical concepts and larger examples demonstrating their applications. End-of-chapter homework problems are included throughout. Including all necessary background material from probability theory, and accompanied online by a solutions manual and PowerPoint slides for instructors, this is the ideal text for senior undergraduate and graduate students taking courses on structural and system reliability in departments of civil, environmental and mechanical engineering.

Phase Diversity Electro-optic Sampling: A new approach to single-shot terahertz waveform recording

Recording electric field evolution in single-shot with THz bandwidth is needed in science including spectroscopy, plasmas, biology, chemistry, Free-Electron Lasers, accelerators, and material inspection. However, the potential application range depends on the possibility to achieve sub-picosecond resolution over a long time window, which is a largely open problem for single-shot techniques. To solve this problem, we present a new conceptual approach for the so-called spectral decoding technique, where a chirped laser pulse interacts with a THz signal in a Pockels crystal, and is analyzed using a grating optical spectrum analyzer. By borrowing mathematical concepts from photonic time stretch theory and radio-frequency communication, we deduce a novel dual-output electro-optic sampling system, for which the input THz signal can be numerically retrieved—with unprecedented resolution—using the so-called phase diversity technique. We show numerically and experimentally that this approach enables the recording of THz waveforms in single-shot over much longer durations and/or higher bandwidth than previous spectral decoding techniques. We present and test the proposed DEOS (Diversity Electro-Optic Sampling) design for recording 1.5 THz bandwidth THz pulses, over 20 ps duration, in single-shot. Then we demonstrate the potential of DEOS in accelerator physics by recording, in two successive shots, the shape of 200 fs RMS relativistic electron bunches at European X-FEL, over 10 ps recording windows. The designs presented here can be used directly for accelerator diagnostics, characterization of THz sources, and single-shot Time-Domain Spectroscopy.

Multimodality and New Materialism in Science Learning: Exploring Insights from an Introductory Physics Lesson

Science disciplines are inherently multimodal, involving written and spoken language, bodily gestures, symbols, diagrams, sketches, simulation and mathematical formalism. Studies have shown that explicit multimodal teaching approaches foster enhanced access to science disciplines. We examine multimodal classroom practices in a physics extended curriculum programme (ECP) through the lens of new materialism. As De Freitas and Sinclair note in their book, Mathematics and the Body, there is growing research interest in embodiment in mathematics (and science) education—that is, the role played by students’ bodies, in terms of gestures, verbalisation, diagrams and their relation to the physical objects with which they interact. Embodiment can be viewed from a range of theoretical perspectives (for example, cognitive, phenomemological, or social semiotic). However, they argue that their new materialist approach, which they term “inclusive materialism”, has the potential for framing more socially just pedagogies. In this article, we discuss a multimodal and new materialist analysis of a lesson vignette from a first-year extended curriculum physics course. The analysis illuminates how an assemblage of bodily-paced steps-gestures-diagrams becomes entangled with mathematical concepts. Here, concepts arise through the interplay of modes of diagrams, gestures and bodily movements. The article explores how multimodal and new materialist perspectives might contribute to reconfiguring pedagogical practices in extended curriculum programmes in physics and mathematics.

Implementasi pendekatan pendidikan matematika realistik ditinjau dari pemahaman konsep, aktivitas, dan respons siswa

This study aims to describe the ability to understand mathematical concepts, activities and student responses in learning mathematics with realistic mathematics education approach. To achieve this goal, a quasi-experimental study was conducted with one group pretest posttest design. The population of the study was the eighth grade students of SMP Negeri 4 Angkola Timur, sampling by purposive sampling, namely class 8-2, totaling 26 students. Research activities include the stages of giving the Pre-test followed by learning for 3 meetings which then ends with a final test. Through research conducted using the Paired Samples Test, a significance of 0.00 < 0.05 was obtained, which gave the decision that the initial hypothesis was accepted. Of the 9 aspects of learning activities studied in the application of realistic mathematics education, the overall average value of the percentage of all activities met the active criteria. Furthermore, the average overall student response to being happy, new, interested and understanding/interested in the implementation of realistic mathematics education is 91.11% ≥ 85%. Thus it is concluded that: 1) The implementation of a realistic mathematics education approach has a significant positive influence in learning students' ability to understand mathematical concepts; 2) Student activities in learning mathematics with realistic mathematics education approach are effective; 3) Student responses to learning activities with realistic mathematics education are in the positive category.

Difficulties in the interpretation of kinematics graphs in secondary basic education students

This research reports the findings derived from the identification of the difficulties exhibited by a group of 76 students from different grades of basic secondary education in a private educational institution with an emphasis on science education. The students were given a questionnaire presenting five situations based on the Position-Time graph associated with uniform rectilinear motion of particles. The research approach is of a quantitative nature at a descriptive level with a field design, since it was the students who filled in the instrument. It is highlighted as a finding in the opinion of the students that the subject has been seen in class, but due to the teacher’s methodology it is not fully understood by them. The results show that the students have a long list of difficulties mainly due to the lack of articulation of mathematical concepts in physical contexts, a situation that prevents them from analyzing the proposed statements, reasoning about the approaches, and improving in the process of searching for alternative solutions with clear arguments.

Use of Computer Simulations for the Understanding and Retention of Mathematical Concepts

Simulations provide unique features and instructional benefits for the improved understanding of concepts. This study aimed to find the effect of computer simulations on the understanding and retention of mathematical concepts. This was an experimental research. A sample of 100 students participated in this experimental research. The sample was further distributed into an equal number of students in two groups. Some topics were selected from the grade–IX mathematics textbook. The selected mathematical topics were taught to the control group by lecture method whereas computer simulations were used for teaching mathematical concepts to the experimental group. Data analysis showed that in the posttest, the experimental group performed better than the control group at a 0.05 level of significance. The scores of the retention test of the experimental group were also found better than the control group. It is recommended to include computer simulations in the teaching-learning process for better comprehension of abstract concepts of mathematics. Keywords: Achievement, Mathematical Concepts, Retention, Simulations

Exploring Project-Based Teaching for Engaging Students' Mathematical Learning

The declining interest of learners in mathematics in the learning process has resulted in poor achievement (Yeh et al., 2019). To get rid of these poor achievements, we explored project-based teaching in four topical areas (e.g., mathematical concepts of coordinate geometry, trigonometry, sequence, and series) in the school mathematics. This paper results from observing changes in engagement of learners in learning mathematics by motivating them through the project-based learning (PBL) guided by two theories – knowledge constitutive interests (Habermas, 1972), and collaborative and cooperative learning under the paradigms of interpretivism and criticalism. In this ethos, PBL is an “engaging and learner-directed approach that provides equal opportunities for students to explore their knowledge and understanding” (Thomas, 2000, p. 12). More specifically, we adopted the 'action research' method with the secondary level students (Grade IX) of one of the institutional schools in their classrooms. The information was collected by observing and recording the changes seen in consecutive seventeen days. The research landed that project-based learning is an appropriate pedagogy for engaged learning. The study revealed that the students were motivated while they got opportunities to interact in the projects. Moreover, the findings show that PBL is helpful to engage the learners through questioning, pair/group discussion, discovery learning, and concept mapping.

PENINGKATAN PEMAHAMAN KONSEP SISWA DENGAN PENDEKATAN METAPHORICAL THINKING PADA PEMBELAJARAN DARING MATERI ARITMATIKA SOSIAL

This research is motivated by the low understanding of students' mathematical concepts, especially on social arithmetic material. The purpose of this study was to describe the stages of the metaphorical thinking approach method and the magnitude of the increase in students' conceptual understanding of social arithmetic material. The data collection method used in this classroom action research (CAR) includes written tests and observations in each cycle. The research instruments used were lesson plans, worksheets, question sheets, and observation sheets for the implementation of learning in each cycle. The research subjects were students of class VII in one of the madrasah tsanawiyah in Lamongan as many as 23 students. Based on the results of data analysis, the classical student activity assessment increased 23.85% from 66.25% to 90.1%. Student test results also increased by 34.8%, namely from cycle I it reached 47.8% and cycle II reached 82.6%, with the results achieved can be declared complete, and it can be concluded that in online mathematics learning there is an increase in understanding concept in class VII madrasah tsanawiyah in Lamongan by using the application of Metaphorical Thinking.

PENDEKATAN SCIENCE, TECHNOLOGY, ENGINEERING, AND MATHEMATICS (STEM): DAMPAKNYA TERHADAP KEMAMPUAN PEMAHAMAN KONSEP MATEMATIS DAN LITERASI AL-QUR’AN

This study aimed to determine the effect of the STEM (Science, Technology, Engineering, and Mathematics) learning approach on the ability to understand mathematical concepts in terms of students' Al-Qur'an literacy. This research is a Quasy Experimental Design research with a 2×3 factorial research design. The data collection techniques in this study were in the form of a concept understanding test and an Al-Qur'an literacy questionnaire. The data analysis technique used is the normality test and homogeneity test, and the Two-way ANOVA test. Based on the results of the study, it was concluded that there was an effect of the STEM learning approach (Science, Technology, Engineering, and Mathematics) on the ability to understand students' mathematical concepts in the material of Building Flat Side Space. There is no influence of Al-Qur'an literacy on the ability to understand students' mathematical concepts in the material of Constructing Flat Sided Space. There is no interaction between the treatment of the STEM learning approach (Science, Technology, Engineering, and Mathematics) with the Al-Qur'an literacy category on the ability to understand mathematical concepts in the matter of Constructing Flat Sided Space.

PENGARUH KECERDASAN LOGIS MATEMATIS DAN KEMANDIRIAN BELAJAR TERHADAP KEMAMPUAN PEMAHAMAN KONSEP MATEMATIS SISWA DALAM PEMBELAJARAN BERBASIS DARING

This study aims to determine the effect of mathematical logical intelligence and self-regulated learning on the ability to understand students' mathematical concepts in online-based mathematics learning. This research is survey research by giving a logical-mathematical intelligence test, a self-regulated learning questionnaire, and a mathematical concept understanding ability test to 142 X grade students in one of the Jakarta State Senior High Schools. Statistical analysis used in this study is multiple linear regression. Based on the results of hypothesis testing, it can be seen that there is an effect of mathematical logical intelligence and self-regulated learning together on the ability to understand students' mathematical concepts in online-based mathematics learning by 49.53%, there is an influence of mathematical logical intelligence significantly on the ability to understand students' mathematical concepts in online-based mathematics learning, and there is no significant effect of self-regulated learning on the ability to understand students' mathematical concepts in online-based mathematics learning.