ANALYSIS OF TRAINING METHOD OF TAEKWONDO ATHLETES WITH REACTION BALL

ABSTRACT Introduction: Brief introduction: Taekwondo is a sport that integrates explosive power and reaction speed. The reaction speed of the athletes has a direct bearing on the result of the competition. Objective: To improve the reaction time effect of athletes. Methods: Forty-one Taekwondo team athletes were selected as the research subjects. Then, the training methods were introduced, and special technology using an emg tester and a synchronous camera system was implemented to analyze the earliest emg signals and the moment of the hit, the time from signal emergence to the emg reaction for reaction time, and from signal emergence to hit for the total time. Results: The average score of the 41 athletes before the test was 0.282673,with standard deviation of 0.0377349 and standard error of 0.0058932. The average score, standard deviation, and standard error of the 41 athletes after small training were 0.28217, 0.037744 and 0.005895. Conclusions: From the test results of the three training modes, the small training mode had a significant impact on the reaction time of Taekwondo athletes, while the medium and large training modes did not have significant effects. The results show that a small amount of training is best and plays a significant role in improving the reaction of an athlete. Level of evidence II; Therapeutic studies - investigation of treatment results.

GNSS Aided Long-Range 3D Displacement Sensing for High-Rise Structures with Two Non-Overlapping Cameras

Image-based displacement measurement techniques are widely used for sensing the deformation of structures, and plays an increasing role in structural health monitoring owing to its benefit of non-contacting. In this study, a non-overlapping dual camera measurement model with the aid of global navigation satellite system (GNSS) is proposed to sense the three-dimensional (3D) displacements of high-rise structures. Each component of the dual camera system can measure a pair of displacement components of a target point in a 3D space, and its pose relative to the target can be obtained by combining a built-in inclinometer and a GNSS system. To eliminate the coupling of lateral and vertical displacements caused by the perspective projection, a homography-based transformation is introduced to correct the inclined image planes. In contrast to the stereo vision-based displacement measurement techniques, the proposed method does not require the overlapping of the field of views and the calibration of the vision geometry. Both simulation and experiment demonstrate the feasibility and correctness of the proposed method, heralding that it has a potential capacity in the field of remote health monitoring for high-rise buildings.

The influence of corneal density and thickness on tonometry measurement with goldmann applanation, non-contact and iCare tonometry methods

Purpose To evaluate the effect of corneal density and thickness on the accuracy of tonometry readings obtained via three most used techniques. Method Intraocular pressures of 45 patients’ right eyes were measured using Goldmann Applanation, iCare, and non-contact tonometry methods. Corneal parameters were obtained using the Pentacam Camera System. Data obtained were analyzed using Paired t Test, Pearson’s correlation coefficient, multiple linear regression analysis, and Bland–Altman plots. Results The mean corneal thickness was 545.4 ± 3.93 μm. The mean corneal density of total, stromal, 0–2 mm, and 2–6 mm zones were 27.85 ± 6.23 GSU, 24.61 ± 6.05 GSU, 20.76 ± 2.96 GSU, and 20.81 ± 3.51 GSU respectively. IOP readings had a statistically significant correlation with corneal stromal thickness, as well as with total and stromal density. The stromal density, however, showed higher correlation with the three tonometry methods than did the total density (iCare: − .482 (0.001) stromal density versus− .464 (0.001) total density, NCT: − .376 (0.011) versus − .353 (0.017), GAT: − .306 (0.041) versus − .296 (0.048)). Statistical differences were found in comparing the iCare readings with GAT (P < 0,00) and with NCT (P < 0,00), with mean differences of 1.8 mmHg ± 2.6 and 2.0 mmHg ± 2.6 respectively. GAT and NCT measurements showed no statistical difference (P > 0.05). Conclusion This study shows that both central corneal thickness and stromal density are significant influential factors of reliable IOP readings. It is necessary to consider more corneal biomechanical properties, as well as exercise a high degree of caution in any new attempts towards adjusting an IOP-correction equation.

Diagnostic intervention program based on construction workers' internal factors for persistent reduction of unsafe behavior

PurposeThis study aims to show what interventions in human factors can effectively reduce construction workers' unsafe behavior.Design/methodology/approachA diagnostic intervention model targeted the construction workers' weakest internal factors. The workers' behavior and cognition data were collected via a questionnaire and a video camera system from two medium-sized construction sites. A safety supervisor accompanied each site supervisor to improve construction workers' internal factors by implementing the designed intervention measures.FindingsThe statistical analysis results confirmed a persistent positive effect on construction workers' safe behavior by improving internal factors. Among the intervention programs applied, those aimed to improve the subjective norms, safety knowledge and attitudes had the most significant effect sizes.Practical implicationsThe findings of this case study advise project managers to design a specific behavioral intervention that aims at improving construction workers' significant internal factors, including subjective norms, safety attitudes, habits and knowledge together with demographic characteristics to reduce construction workers' unsafe behavior.Originality/valueWhile the declining rate of construction accidents approaches an asymptote which is still high, this study suggests that targeting the individual internal factors through diagnostic interventions is the key to further reduce the rate by improving construction workers' behavior.

Intelligent electromagnetic metasurface camera: system design and experimental results

Electromagnetic (EM) sensing is uniquely positioned among nondestructive examination options, which enables us to see clearly targets, even when they visually invisible, and thus has found many valuable applications in science, engineering and military. However, it is suffering from increasingly critical challenges from energy consumption, cost, efficiency, portability, etc., with the rapidly growing demands for the high-quality sensing with three-dimensional high-frame-rate schemes. To address these difficulties, we propose the concept of intelligent EM metasurface camera by the synergetic exploitation of inexpensive programmable metasurfaces with modern machine learning techniques, and establish a Bayesian inference framework for it. Such EM camera introduces the intelligence over the entire sensing chain of data acquisition and processing, and exhibits good performance in terms of the image quality and efficiency, even when it is deployed in highly noisy environment. Selected experimental results in real-world settings are provided to demonstrate that the developed EM metasurface camera enables us to see clearly human behaviors behind a 60 cm-thickness reinforced concrete wall with the frame rate in order of tens of Hz. We expect that the presented strategy could have considerable impacts on sensing and beyond, and open up a promising route toward smart community and beyond.

Validation of a Method for Measuring the Position of Pick Holders on a Robotically Assisted Mining Machine’s Working Unit

For effective mining, it is essential to ensure that the picks are positioned correctly on the working unit of a mining machine. This is due to the fact that the design of roadheader cutting heads/drums using computer-aided tools is based on the operating conditions of the roadheader/shearer/milling machine. The geometry of the cutting head is optimized for selected criteria by simulating the mining process using a computer. The reclaimed cutting head bodies that are utilized in production are manufactured again in the overhaul process. Ensuring that the dimensions of the cutting head bodies match the rated dimensions is labor-intensive and involves high production costs. For dimensional deviations of the cutting head bodies, it is necessary to control the position of the pick holders relative to the cutting head side surface in real time during robotic-assisted assembly. This article discusses the possibility of utilizing a stereovision system for calculating the distance between the pick holder base and the roadheader cutting head side surface at the point where the pick holder is mounted. The proposed measurement method was tested on a robotic measurement station constructed for the purpose of the study. A mathematical measurement model and procedures that allow automatic positioning of the camera system to the photographed objects, as well as acquisition and analysis of the measurement images, were developed. The proposed method was validated by using it for measuring the position of the pick holders relative to the side surface of the working unit of a mining excavating machine, focusing on its application in robotic technology. The article also includes the results observed in laboratory tests performed on the developed measurement method with an aim of determining its suitability for the metrology task under consideration.

Aqua-Vision (An underwater panoramic camera with computer vision and analytics)

In the present social media-bound lifestyle, capturing memories and keeping them accessible is gaining a significant demand globally. For this purpose, a robust, portable camera system for recreational or commercial purposes can be of substantial advantage to society. Aqua-Vision intends to bring an affordable underwater camera system with various innovative features to the hands of consumers. The smart module consists of a waterproof gimbal camera that can be used underwater, providing a hassle-free and reliable user experience and offers rotary motion along two axes. The camera features various general modes like panorama, burst shot, and smart modes using inbuilt computer vision algorithms. The gimbal camera setup can be controlled and switched remotely between all possible modes using a mobile application. All the above features will allow the user to capture photos/videos in any possible setup and use the camera module for various applications. The advent of such innovative, convenient, and robust modules will help cater to the market demands effectively.

HEXITEC 2 × 2 tiled hard X-ray spectroscopic imaging detector system

HEXITEC is a spectroscopic imaging X-ray detector technology developed at the STFC Rutherford Appleton Laboratory for X-ray and γ-ray spectroscopic imaging applications. Each module has 80 × 80 pixels on a 250 μm pixel pitch, and has been implemented successfully in a number of applications. This paper presents the HEXITEC 2 × 2 detector system, a tiled array of 4 HEXITEC modules read out simultaneously, which provides an active area of 16 cm2. Systems have been produced using 1 mm thick Cadmium Telluride (CdTe) and 2 mm thick Cadmium Zinc Telluride (CdZnTe) sensor material. In this paper the system and data processing methods are presented, and the performance of the systems are evaluated. The detectors were energy calibrated using an 241Am sealed source. Three types of charge sharing correction were applied to the data-charge sharing addition (CSA), charge sharing discrimination (CSD), and energy curve correction (ECC) which compensates for energy lost in the inter-pixel region. ECC recovers an additional 34 % of counts in the 59.5 keV peak in CdTe compared to the use of CSD; an important improvement for photon-starved applications. Due to the high frame rate of the camera system (6.3 kHz) an additional End of Frame (EOF) correction was also applied to 6.0 % of events to correct for signals that were readout whilst the signal was still forming. After correction, both detector materials were found to have excellent spectroscopic performance with a mean energy resolution (FWHM) of 1.17 keV and 1.16 keV for CdZnTe and CdTe respectively. These results successfully demonstrate the ability to construct tiled arrays of HEXITEC modules to provide larger imaging areas.

On an application of node MCU Esp8266 in opening and closing the laboratory door - online practice

This paper presents an application of ESP8266 node MCU in building a networked laboratory door opening and closing system (NLDOC system). The article mentions the function of the ESP8266 node MCU [1-3], and the Arduino application to serve as the basis for the development of an application that connects computers and smartphones [5-6], allowing to control the door latch of the practical labs remotely via Wi-Fi combined with security monitoring through the camera system [4].

EFFECT OF SEED FILLING AND RELEASING ANGLES ON THE PERFORMANCE OF COMPOUND VACUUM SEED METERING DEVICE

In this paper, taking compound air-suction seed metering device as the subject, the effect rule of seed filling angle and seed releasing angle on the performance of seed filling and seed metering is studied. An indoor test was conducted with a JPS-12 metering test bench and a high-speed camera system. The starting and ending angles of the air chamber were changed by adjusting the regulating plate, that is, the angles of seed filling and seed releasing, and the filling and seed metering performance was taken as evaluation indexes. The test results show that: the seed filling angle has significant effect on the seed filling effect, and the miss fill index decreases with the increase of the quality of fill index. When the seed filling angle exceeds 50°, they will stabilize gradually ending at the multiple fill index of 0%. The negative pressure and operating speed are interactive and have a significant effect on filling performance. The seed releasing angle has significant effect on the metering performance. With the increase of the angle, the quality of feed index increases firstly and then decreases. The multiple index and miss index are opposite to the quality of feed index which is the max at the seed releasing angle of 39.5°. The negative pressure and forward speed are interactive and have a significant effect on metering performance. The quality of feed index under the same condition is lower than that of fill index.