Effects of robot for teaching geometry to fourth graders

The results of the TIMSS 2007 (International Association for the Evaluation of Educational Achievement, 2008) show that in comparison with their academic achievement in mathematics, South Korean students’ interest and efficacy in and self-concept in relation to the discipline rank relatively low. In the effort to help address this issue, this study investigated the effects of the implementation of robot in an elementary-level Korean math class, examining student cognitive and affective domains before, immediately after, and three months after treatment. The participants in this study were 121 fourth graders (11 to 12 years old) at a public elementary school in an urban district in Korea. The participants were randomly selected from four classes and then randomly assigned to either the “Robot” group (58 children) or the “Ruler & Protractor” group (63 children). Our findings are as follows: concerning student achievement in the cognitive domain, no statistically significant result was found. As for the affective domain, after treatment, the Robot group’s levels of interest and curiosity toward mathematics and participation in their mathematics class were statistically higher than those of the Ruler & Protractor group. This remained true at the delayed posttest. A correlation analysis between achievements in cognitive domain, results of the observation test during class, and results of the self-assessment test in affective domain showed that in the case of the Ruler & Protractor group, their instruction in mathematics class only contributed to cognitive domain. However, in the case of the Robot group, treatment contributed to both cognitive and affective domains. In conclusion, robots have potential to replace traditional ruler and protractor use in geometry education from the perspective of their effects on cognitive and affective domains

Multislice B₁ Mapping Method Using Magnetic Resonance Composite Spin Echo Sequences and Simultaneous Echo Refocusing

Radiofrequency (RF) transmit field (B1) mapping is a promising method in mitigating the B1 inhomogeneity in various magnetic resonance imaging (MRI) applications. Although several phase- or magnitude-based B1 mapping methods have been proposed, these methods often require complex modeling, long acquisition time, or specialized MRI sequences. A recently introduced simultaneous echo refocusing (SER) technique can be applied in the B1 mapping method to extend the three-dimensional (3D) spatial coverage only without long data acquisition. Therefore, in this study, a multislice B1 mapping method using composite spin echo sequences and SER techniques is proposed to obtain more accurate B1 mapping with short data acquisition time. To evaluate the performance of the proposed B1 mapping method, computational simulations were performed and compared with Morrell’s method, double angle method, and Yarnykh’s method. These results showed that the angle-to-noise ratio of the proposed B1 mapping method has wider B1 range compared to that of other B1 mapping methods. In addition, the proposed B1 mapping methods were compared to the multislice iterative signal intensity mapping method in both phantom and in vivo human experiments, and there was no remarkable difference between the two methods regarding the flip angle distribution in these experiments. Based on these results, this study demonstrated that the proposed B1 mapping method is suitable for accurately measuring B1 propagation under the condition providing reduced scan time and wider 3D coverage of B1 mapping by applying composite RF pulse and SER techniques into the phase-sensitive method

Whole-brain imaging with receive-only multichannel top-hat dipole antenna RF coil at 7 T MRI

This work investigates the construction and performance of an eight-channel top-hat dipole receiver RF coil with a capacitive plate to increase the longitudinal whole-brain coverage and receiver sensitivity gain in the brain at 7 T MRI. The construction method for top-hat dipole-based receiver RF coil by adjusting the length and structure corresponding to each channel consists of tuning, matching, balun, and detuning circuitry. Electromagnetic simulations were analyzed on a 3-D human model to evaluate B1+ efficiency and specific absorption rate deposition. Coil performance was evaluated in the human head imaging in vivo. EM simulation results indicated a higher B1− sensitivity in the brain and z-directional coverage of the proposed eight-channel receiver RF coil. The MR images were acquired with an identical field of view showing the receiver coverage improvement in the brain when capacitive plates are used. The MR images also show the clear visibility of the complete set of the cervical vertebrae as well as the spinal cord. The acquired MRI results demonstrate the capability of the proposed RF coil to increase the receiver coverage in the longitudinal direction. Moreover, the B1+ efficiency, as well as receiver sensitivity in the brain, can be substantially improved with the use of multilayered capacitive plates of proper shape and size in conjunction with an RF coil

A Novel Magnetic Resonance Quality Assurance Phantom (KMRP-4): Multi-Site Comparison With the American College of Radiology Phantom

Purpose: To propose a novel standard magnetic resonance imaging (MRI) phantom, hereafter called the Korea Magnetic Resonance Phantom-4th edition (KMRP-4). Its related quality control (QC) assessment protocols and its comparison with the American College of Radiology (ACR) phantom and its QC assessment protocols. / Materials and Methods: Internally, the KMRP-4 phantom is composed of cubic and triangular vessels, brain tissue structures, and a uniform region designed to facilitate a variety of QC protocols. Using magnetic resonance (MR) images of these structures, we quantitatively evaluated a total of 10 parameters, seven from those of existing ACR protocols (i.e., geometric accuracy, high-contrast spatial resolution, slice thickness accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting, and low-contrast object detectability) and three additional parameters for evaluating vessel conspicuity, brain tissue contrast, and signal-to-noise ratio (SNR) introduced in the KMRP-4 protocols. Twentyt-wo MRI systems of 0.32–3.0 T static magnetic field strength were tested using both ACR and KMRP-4 phantoms. Mann–Whitney U-tests were performed on the seven evaluation items of the ACR method to compare KMRP-4 and ACR methods. / Results: The results of Mann–Whitney U-test demonstrated that p-values were more than 0.05 for all seven items that could be assessed with both ACR and KMRP-4, indicating similar results between the two methods. Additionally, assessments of vessel conspicuity, brain tissue contrast, and SNR using the KMRP-4 method demonstrated utility of the KMRP-4 phantom. / Conclusion: A novel standard phantom and related QC methods were developed to perform objective, observer-independent, and semi-automatic QC tests. Quantitative comparisons of MR images with KMPR-4 and ACR phantoms were performed. Results demonstrated the utility of the newly proposed KMRP-4 phantom and its related QC methods

Identifying core technologies based on technological cross-impacts: An association rule mining (ARM) and analytic network process (ANP) approach

This study proposes a new approach to identifying core technologies from a perspective of technological cross-impacts based on patent co-classification information with consideration of the overall interrelationships among technologies. The proposed approach is comprised of two methods: association rule mining (ARM) and the analytic network process (ANP). Firstly association rule mining (ARM) is employed to calculate the technological cross-impact indexes. Since the confidence measure in ARM is defined as a conditional probability between two technologies, it is adopted as an index for evaluating technological cross-impacts. The technological cross-impact matrix is then constructed with all calculated cross-impact indexes. Secondly. the ANP, which is a generalization of the analytic hierarchy process (AHP), is conducted to produce priorities of technologies with consideration of their direct and indirect impacts. The proposed approach can be utilized for technology monitoring for both technology planning of firms and innovation policy making of governments. A case of telecommunication technology is presented to illustrate the proposed approach.close