Search

Developing models and using mathematics are two key practices in internationally recognized science education standards, such as the Next Generation Science Standards (NGSS). However, students often struggle with these two intersecting practices, particularly when developing mathematical models about scientific phenomena. Formative performance-based assessments designed to elicit fine-grained data about students' competencies on these practices can be leveraged to develop embedded AI scaffolds to support students' learning. In this paper, we present the design and initial classroom test of virtual labs that automatically assess fine-grained sub-components of students' mathematical modeling competencies based on their actions within the learning environment. We describe how we leveraged underlying machine-learned and knowledge-engineered algorithms to trigger scaffolds, delivered proactively by a pedagogical agent, that address students' individual difficulties as they work. Results show that the students who received automated scaffolds for a given practice on their first virtual lab improved on that practice for the next virtual lab on the same science topic in a different scenario (a near-transfer task). These findings suggest that real-time automated scaffolds based on fine-grained assessment can foster students' mathematical modeling competencies related to the NGSS.

Numerical models serve an important role in eddy current non-destructive evaluation applications. The results of computational models provide meaningful insight into the underlying physics, help theoretically visualize the field/sample interaction and help optimize sensor design and assist algorithms developing for interpreting the measured signals. However, three dimensional computational models can be time consuming. This paper presents a fast and efficient GPU based numerical model for simulating eddy current testing techniques. The model, based on boundary integral method, uses novel matrix compression techniques to optimize the solver performance on GPU architectures. Validation results of model predictions for a number of sample geometries are presented. [ABSTRACT FROM AUTHOR]

This paper presents the formulation of an axi-symmetric element based on an efficient method called 'Inverse Approach' (I.A.) for the numerical modeling of cold forging process. In contrast to the classical incremental methods, the Inverse Approach exploits the known shape of the final part and executes the calculation from the final part to the initial billet. The assumptions of the proportional loading and the simplified tool actions make the I.A. calculation very fast. The metal's incompressibility is ensured by the penalty method. The comparison with ABAQUS® and FORGE® shows the efficiency and limitations of the I.A. This simplified method will be a good tool for the preliminary preform design. [ABSTRACT FROM AUTHOR]

The standard of IEEE802.11a was introduced first in this paper. And then presents the design and implementation of a simulation model for physical layer in the WLAN system with the simulation tool MATLAB and has realized the simulation, which include timing synchronization and frequency synchronization. The simulation result shows that the algorithm presented possesses low complexity in implementation as well as high precision. [ABSTRACT FROM AUTHOR]

This article discusses the possibilities in the area of modeling of the so called cooling tower plume emergent at operating evaporating cooling systems. As opposed to recent publication, this text focuses on the possibilities of a simplified analytic description of the whole problem where this description shall - in the future - form the base of a calculation algorithms enabling to simulate the efficiency of systems reducing this cooling tower plume. The procedure is based on the application of basic formula for the calculation of the velocity and concentration fields in the area above the cooling tower. These calculation is then used to determine the form and the total volume of the plume. Although this approach does not offer more exact results, it can provide a basic understanding of the impact of individual quantities relating to this problem. [ABSTRACT FROM AUTHOR]

The problem of designing of an adaptive and high-accuracy control system for orientation of flexible spacecraft (FS) is considered. It is assumed that control is a relay one. In this case elastic oscillations of spacecraft flexible elements are the most dangerous from the viewpoint of control system stability. Also it is assumed that for control only limited information about object's co-ordinates can be used and the FS mathematical model is nonstationary and (or) badly defined. It is presented the procedure of the synthesis of the adaptive control algorithm with reference model that is based on Lyapunov's method. The structure of a combined control system is suggested. It has a subsystem of the elastic oscillations damping during the intervals of the FS' passive motion that correspond to the dead zone of relay control algorithm. The computer simulation results illustrating workability and control quality of combined adaptive system are described. [ABSTRACT FROM AUTHOR]