Interpreting learning progress using assessment scores: what is there to gain?

Using assessment scores to quantify gains and growth trajectories for individuals and groups can provide a valuable lens on learning progress for all students. This paper summarises some commonly observed patterns of progress and illustrates these using data from ACER’s Progressive Achievement Test (PAT) assessments. While growth trajectory measurement requires scores for the same individuals over at least three but preferably more occasions, scores from only two occasions are naturally more readily available. The difference between two successive scores is usually referred to as gain. Some common approaches and pitfalls when interpreting individual student gain data are illustrated. It is concluded that pairs of consecutive scores are best considered as part of a longer-term trajectory of learning progress, and that caveated gain information might at best play a peripheral role until additional scores are available for individuals. This review is part of a larger program of research to inform future reporting developments at ACER.

SUGGESTIONS FOR TYPICAL METHODS OF USING DOPPLER RADAR SYSTEMS OF TRAJECTORY MEASUREMENTS DURING TESTS OF ARTYLLERY ARMAMENT AND ITS AMMUNITION

The article analyzes the report documentation of the tests in which the Doppler radar trajectory measurement system MFTR–2100/40 and the muzzle velocity measurement system SL-520PE were used to determine the trajectory parameters of artillery armament. The purpose of the article is to provide proposals for standard methods of using Doppler radar systems of trajectory measurements when testing artillery armament and its ammunition. The proposals for these standard methods are based on the experience of using the MFTR–2100/40 radar system and the SL–520PE muzzle velocity measurement system during the tests of the latest specimens of artillery and ammunition and relate to typical Doppler radar systems. When choosing the position and mode of operation of such Doppler radar trajectory measurement systems, it is always necessary to take into account safety measures, instructions for their operation, technical features (capabilities) of radar systems specified in this article, considering the interference environment during firing (shot) of artillery armament and experiment (test) conditions. Placing typical Doppler radar systems when taking measurements in unplanned places is dangerous for the crew and measuring instruments and leads to partial or complete loss of measuring trajectory information and reduced measurement accuracy. Abovementioned proposals are offered to be taken into account when developing methods of trajectory measurements using typical Doppler radar systems during testing artillery armament and its ammunition. Methods of measurements using standard Doppler radar systems of trajectory measurements should be developed in accordance with current standards (GOST 8.010-99, GOST V 15.211-78 and others) for a particular test, taking into account the results of analysis of the characteristics of samples to be evaluated, measuring instruments used, conditions and locations of measurements.

Speculum Observation and Trajectory Measurement in Gas Extraction Drilling: A Case Study of Changling Coal Mine

Coal will still be China’s basic energy for quite a long time. With the increase of mining depth, gas content and pressure also increase. The problems of gas emission and overrun affect the safety and efficient production of coal resource to a certain extent. In this work, the field test of gas drainage borehole peeping and trajectory measurement in coal seam of Changling coal mine are carried out. These coal seams include C5b coal seam, upper adjacent C5a coal seam, C6a coal seams, C6c in lower adjacent strata, and C5b coal seam in high-level borehole. The view of gas drainage borehole peeping and trajectory measurement in the working seam, upper adjacent layer, lower adjacent layer, and high position are obtained. It is found that the hole collapses at the position of about 20 m in both adjacent strata and high-level boreholes, and there are a lot of cracks in the high-level boreholes before 12 m. The deviation distance of high-level borehole is large, and the actual vertical deviation of upper adjacent layer is small. Finally, the strategies to prevent the deviation of drilling construction are put forward. It includes four aspects: ensuring the reliability of drilling equipment, reasonably controlling the drilling length, standardizing the drilling, and reasonably selecting the drilling process parameters.

Orthogonality Measurement of Three-Axis Motion Trajectories for Micromanipulation Robot Systems

In robotic micromanipulation systems, the orthogonality of the three-axis motion trajectories of the motion control systems influences the accuracy of micromanipulation. A method of measuring and evaluating the orthogonality of three-axis motion trajectories is proposed in this paper. Firstly, a system for three-axis motion trajectory measurement is developed and an orthogonal reference coordinate system is designed. The influence of the assembly error of laser displacement sensors on the reference coordinate system is analyzed using simulation. An approach to estimating the orthogonality of three-axis motion trajectories and to compensating for its error is presented using spatial line fitting and vector operation. The simulation results show that when the assembly angle of the laser displacement sensors is limited within a range of 10°, the relative angle deviation of the coordinate axes of the reference coordinate frame is approximately 0.09%. The experiment results show that precision of spatial line fitting is approximately 0.02 mm and relative error of the orthogonality measurement is approximately 0.3%.

Soyuz-FG and Soyuz-2 1a space rockets trajectory parameters in comparative analysis based on external trajectory measurement data

In order to identify the distinctive features of using analog and digital control systems, a comparative analysis of kinematic parameters of movement of two space rockets was carried out. Relying on the external trajectory measurement data, we developed a method for calculating the estimates of statistical characteristics of isochronous variations in the parameters of the state vector of the space rockets. Within the study, we compared and analyzed the kinematic parameters of the movement of Soyuz-FG and Soyuz-2 1a space rockets. Using the external trajectory measurement data, we calculated the spacecraft initial orbit parameters formed by the considered launch vehicles, and estimated their accuracy. Findings of research show that the parameters of the initial orbit formed by Soyuz-2 have smaller deviations from their nominal values, unlike the launch trajectory of the previous generation launch vehicle. Experimental data have confirmed the positive contribution of terminal control to reducing deviations of the implemented trajectory from the nominal one.

Geometric Design and Prototyping of a (2-RRU)-URR Parallel Mechanism for Thumb Rehabilitation Therapy

In this paper, the geometrical design of a (2-RRU)-URR (where R and U stand for the revolute and universal joints, respectively) parallel mechanism was demonstrated for thumb rehabilitation therapy. This paper consists of two parts: the design procedure for the development of a thumb rehabilitation device and the user experiment with the prototype. Because the hand generally has a limited working area, the design of the hand attachment parts and the placement of the actuators requires careful consideration of the various factors. Along with the kinematic requirements of the device, the interaction between the mechanism and the fingers must be considered. The proposed mechanism has three actuators placed in the hand attachment. When the mechanism is attached to the hand, there is the possibility of collisions between the fingers of the user and the mechanism. Two design candidates were devised while considering the limited working area of the hand and the need to avoid collisions. Due to the dependency of the workspace on the placement of the actuators, a comparison of the workspace of the two candidate designs and the target workspace was carried out. The target workspace was determined through the use of thumb trajectory measurement data. A prototype was manufactured using 3D printed plastic and aluminum materials. To confirm the practical performance of the prototype, user experiments were conducted in which a comparison between the thumb measurement data and the controlled trajectory of each person was done. Motion in two directions, specifically, adduction–abduction and flexion–extension were performed. The results showed that the controlled trajectory of flexion–extension were closely matched to the thumb measurement trajectory. Finally, the experimental results are discussed.

Source regions for meteorite falls

<p>Over the past decade there has been a large increase in the number of automated camera networks that monitor the sky for fireballs. One of the goals of these networks is to provide the necessary information for linking meteorites to their pre-impact, heliocentric orbits and ultimately to their source regions in the solar system. We re-computed heliocentric orbits for the 25 meteorite falls published in or before 2016 from original data sources (Granvik and Brown 2018). Using these orbits, we constrained their most likely escape routes from the main asteroid belt and the cometary region by utilizing a state-of-the-art orbit model of the near-Earth-object population (Granvik et al. 2016), which includes a size-dependence in delivery efficiency. While we find that the general results for escape routes are comparable to previous work, the role of trajectory measurement uncertainty in escape-route identification is explored for the first time. Moreover, the improved size-dependent delivery model substantially changes likely escape routes for several meteorite falls, most notably Tagish Lake which seems unlikely to have originated in the outer main belt as previously suggested. In addition, we find that reducing the uncertainty of fireball velocity measurements below about 0.1 km/s does not lead to reduced uncertainties in the identification of their escape routes from the asteroid belt and, further, their ultimate source regions. The analysis suggests that camera networks should be optimized for the largest possible number of meteorite recoveries with measured speed precisions of order 0.1 km/s. We will present updated results based on a new NEO model (Granvik et al. 2018) and complement our data set with the falls that have been reported since 2016.</p> <p><strong>References:</strong> <br />Granvik, M. and Brown, P. (2018). "Identification of meteorite source regions in the Solar System", Icarus 311, 271-287. <br />Granvik, M., Morbidelli, A., Jedicke, R., Bolin, B., Bottke, W. F., Beshore, E., Vokrouhlicky, D., Delbo, M., Michel, P. (2016). "Super-catastrophic disruption of asteroids at small perihelion distances", Nature 530, 303-306.<br />Granvik, M., Morbidelli, A., Jedicke, R., Bolin, B., Bottke, W. F., Beshore, E., Vokrouhlicky, D., Nesvorny, D., Michel, P. (2018). "Debiased orbit and absolute-magnitude distributions for near-Earth objects", Icarus 312, 181-207.</p>