-
A Magnetometer Calibration Method Using Single-Axis Motion Trajectory and Unscented Kalman Filter for Body Motion Capture Applications
Farzan Farhangian,
Saoussen Bilel,
Faramarz Farhangian,
Rene Jr. Landry
Issue:
Volume 9, Issue 1, June 2021
Pages:
1-10
Received:
18 December 2020
Accepted:
25 December 2020
Published:
12 January 2021
Abstract: Magnetometer calibration is a pre-processing step in the Attitude and Heading Reference Systems (AHRS) which has an essential role in many applications. The main purpose of this article is to derive an innovative and precise calibration approach for a magnetometer set installed on human body. To execute this calibration method, all the error parameters of multiple magnetometers are considered in an Unscented Kalman Filter (UKF) model for accurate estimation of calibration parameters. As achieving a precise estimation in Kalman filters-based algorithms needs an accurate and complete observation model, a special single-axis rotation trajectory for Inertial Measurement Unit (IMU) is performed to increase the observability rank of the calibration model. To evaluate the proposed method, five body-mounted sensors were experimented in the laboratory at the same time for applying in the body motion capture system. The results showed that all five sensors were well-calibrated without any need to be detached from the body and using any rotational robot arm. The resolution and precision of the proposed calibration method are assessed by the ellipsoid-fitting representation method. Consequently, all the body-mounted magnetometers were calibrated, on average, by about 1% uncertainty. The method can be used in every motion capture and AHRS applications due to its feasibility and simplicity.
Abstract: Magnetometer calibration is a pre-processing step in the Attitude and Heading Reference Systems (AHRS) which has an essential role in many applications. The main purpose of this article is to derive an innovative and precise calibration approach for a magnetometer set installed on human body. To execute this calibration method, all the error parame...
Show More
-
Computer Vision Syndrome and Its Predictors Among Secretary Employees Working in Jimma University, Southwest Ethiopia
Mekonnin Tesfa,
Mohammed Ibrahim,
Yohannes Markos,
Ashete Adere,
Leyla Temam
Issue:
Volume 9, Issue 1, June 2021
Pages:
11-18
Received:
18 December 2020
Accepted:
29 December 2020
Published:
22 January 2021
Abstract: Background: Computer users are at high risk to experience eye discomfort and vision problems when viewing digital screens for extended periods. These problems are collectively termed Computer Vision Syndrome (CVS). Nearly more than 60 million people suffer from CVS globally with a million new cases occurring each year. The magnitude of CVS and its determinants are not well known in Ethiopia. Thus, the aim of the study was to determine the prevalence of CVS and its predictors among secretary employees working in Jimma University, Ethiopia. Methods: An institution-based cross-sectional study was conducted on 217 secretary employees working at Jimma University. An interviewer-administered structured questionnaire was used to collect data. Data was collected through face to face interview. The collected data first entered Epi-data version 3.1 and then transformed into SPSS version 20.0 for data analysis. Binary logistic regressions were carried out to determine variables associated with CVS. Results: The prevalence of CVS among study participants was 75.6% (95% CI=70.0, 81.1). Blurred vision 88 (40.6%), extra-ocular symptoms 75 (34.6%), eyestrain 66 (30.4%), and headache 63 (29.0%) were the most commonly reported symptoms of CVS. Duration of occupation >10 years (Adjusted odds ratio (AOR) =3.165; 95%CI=1.16,) working on the computer on average for >6 hours per day (AOR=3.163; 95%CI=1.52, 6.59), not adjusting computer screen brightness (AOR=2.81; 95%CI=1.22, 6.47) and lack of awareness about CVS and its prevention measures (AOR=5.385; 95%CI= 2.55, 11.35) were factors at higher risk of developing CVS. Conclusion: CVS is highly prevalent among secretary employees working at Jimma University. Arranging training program/health education to increase awareness on CVS and its prevention measures might minimize the risk of suffering CVS.
Abstract: Background: Computer users are at high risk to experience eye discomfort and vision problems when viewing digital screens for extended periods. These problems are collectively termed Computer Vision Syndrome (CVS). Nearly more than 60 million people suffer from CVS globally with a million new cases occurring each year. The magnitude of CVS and its ...
Show More
-
Design and Evaluation Method of Wireless Fire Detection Node Based on Multi-source Sensor Data Fusion
Huang Ye,
Wang Xiaogang,
Gan Shuchuan
Issue:
Volume 9, Issue 1, June 2021
Pages:
19-24
Received:
17 January 2021
Accepted:
25 January 2021
Published:
30 January 2021
Abstract: In view of the problem that the traditional fire detection node is not intelligent enough for data processing when building fire occurs, a design and evaluation method of wireless fire detection node based on multi-source sensor data fusion is proposed. Firstly, the temperature and humidity sensor, carbon monoxide sensor and smoke sensor are selected to collect three kinds of fire information eigenvalues at the same time. Secondly, the analysis and processing method of two-level data fusion is established, and the fire information is processed in STC89C52 microcontroller. The first level data fusion uses fuzzy proximity algorithm to get the eigenvectors of environmental parameters, so that the measured values are closer. The second level data fusion uses D-S evidence theory to analyze the data systematically. According to the probability distribution function after fusion, more accurate decision results are obtained. Finally, the fire signal is sent to the superior data management center through ZigBee wireless transmission network, and the alarm signal is triggered in time. The whole node design gives a complete hardware selection and software data fusion processing method. Compared with the traditional fire detection node, it significantly reduces the false alarm rate. At the same time, the node has good application effect in the experiment, and realizes a wireless intelligent fire detection node with low cost, wide application range and high intelligence.
Abstract: In view of the problem that the traditional fire detection node is not intelligent enough for data processing when building fire occurs, a design and evaluation method of wireless fire detection node based on multi-source sensor data fusion is proposed. Firstly, the temperature and humidity sensor, carbon monoxide sensor and smoke sensor are select...
Show More
-
Design and Construction of a Sensor Analytics System for the Monitoring of the Parameters of a Plastic Injection Mould
Babalola Akinloluwa Samuel,
Duncan Folley
Issue:
Volume 9, Issue 1, June 2021
Pages:
25-29
Received:
25 January 2021
Accepted:
2 February 2021
Published:
23 April 2021
Abstract: Values of parameters such as temperature, humidity, number of plastic products and the location of plastic injection moulds are required to determine the efficiency of plastic injection moulds with a view to improving the quality of the outputs. This article determined the appropriate sensors for the measurement of these essential parameters in the most suitable form of representation of the data to aid a proficient analysis of the data. A network of sensors for the measurement and analysis of the parameters of plastic injection moulds in operation was designed and constructed. The outputs of these sensors were obtained by connecting the sensors to the General-Purpose Input/Output (GPIO) pins of a Raspberry Pi and writing a Python programme for the connected GPIO pins. The values of the outputs of these sensors were represented in graphical form. The connection of the Raspberry Pi and the sensors were done with a full-sized breadboard and jumper wires. A computer-aided design (CAD) of the connections was produced using Fritzing software. The appropriate sensors determined are MLX90614 infrared thermometer sensor, DHT11 humidity sensor, pixy2 vision sensor and Neo-6m GPS sensor. The output values of these sensors were plotted on a graph with the aid of a Python programme. The plastic industry has grown into a very broad industry as plastics are used to manufacture many materials. This makes it essential to ensure the efficiency of the industrial machines used in the making of these plastic products by using sensors to measure the parameters of a plastic injection mould in operation. This study therefore suggested the measurement of industrial plastic injection moulds with the use of the built sensors analytics system for the purpose of understanding and improving the performance of the injection mould.
Abstract: Values of parameters such as temperature, humidity, number of plastic products and the location of plastic injection moulds are required to determine the efficiency of plastic injection moulds with a view to improving the quality of the outputs. This article determined the appropriate sensors for the measurement of these essential parameters in the...
Show More
-
People’s Fast Moving Detection Method in Buses Based on YOLOv5
Zhang Xiaoping,
Ji Jiahui,
Wang Li,
He Zhonghe,
Liu Shida
Issue:
Volume 9, Issue 1, June 2021
Pages:
30-37
Received:
26 April 2021
Accepted:
10 May 2021
Published:
20 May 2021
Abstract: To ensure the public’s safety such as in buses, it is very important to accurately judge people’s behaviors and give early warnings. If by watching the video surveillance manually, the cost will be very high, and it cannot be effectively popularized, so video automatic monitoring is preferred. For buses, its environmental space is closed as well as narrow, and at the same time, it is often in a non-stationary state, so traditional behavior detection methods cannot be used here as they are easily affected by moving environment and difficult to fulfill object behavior identification in real time. Aiming at this problem, for people’s fast-moving in buses, a kind of detection method based on YOLOv5 is proposed in this paper. Firstly, the method detects people through one-stage object detection. Secondly, in order to obtain the person's movement trajectory quickly and accurately, an improved two-stage object matching algorithm is designed to track different people. Then, the speed curves of a person during normal activities and fast moving are compared. Finally, an abnormal alarm mechanism is constructed to realize the effective fast movement alarm. Surveillance video in the bus was used to test and evaluate the effectiveness of the method. Results show that the accuracy rate of our method can get 95.4%.
Abstract: To ensure the public’s safety such as in buses, it is very important to accurately judge people’s behaviors and give early warnings. If by watching the video surveillance manually, the cost will be very high, and it cannot be effectively popularized, so video automatic monitoring is preferred. For buses, its environmental space is closed as well as...
Show More
-
Guaranteed Cost Control Research for Networked Control System with Time-Varying Sampling Period
Issue:
Volume 9, Issue 1, June 2021
Pages:
38-44
Received:
28 April 2021
Accepted:
21 May 2021
Published:
27 May 2021
Abstract: In practical industrial applications, the networked control system is often affected by external factors and internal components in operation, which leads to the fluctuation of some data transmitted by the system and reduces the system performance. Therefore, to ensure the normal operation of the system is the key, on this basis, we also need to make the system satisfy certain performance indicators. In this paper, guaranteed cost control for networked control systems with time delay and time-varying sampling period is studied. By constructing a more general system model, we give a design method of guaranteed performance controller to make the closed-loop system asymptotically stable within the allowable range and and satisfies certain performance indicators. Firstly, we construct the reasonable Lyapunov function and performance index function. According to the relevant lemma, the sufficient conditions for the stability of the system are obtained by equivalent transformation of LMI. Then, we design a guaranteed performance controller to minimize the upper bound of the system performance index. In the design process, more free variables are introduced, and the convexity of the function is used for equivalent transformation as far as possible to make the results less conservative. Finally, we use MATLAB to simulate and prove that the method is feasible.
Abstract: In practical industrial applications, the networked control system is often affected by external factors and internal components in operation, which leads to the fluctuation of some data transmitted by the system and reduces the system performance. Therefore, to ensure the normal operation of the system is the key, on this basis, we also need to ma...
Show More
-
Power Regulation System and Charge-discharge Test Applied in Power Grid Based on the Flywheel Energy Storage Array
Issue:
Volume 9, Issue 1, June 2021
Pages:
45-52
Received:
14 June 2021
Accepted:
24 June 2021
Published:
29 June 2021
Abstract: Due to a larger intervention application of the wind-photovolatic new energy generation system, the stability and reliability of the main power grid will be greatly affected. One of the most effective methods to improve the quality of the power grid is to add the energy storage euipment. Based in this, according to the energy storage demand of short term and high frequency in the power grid, this paper focuses on a kind of power regulation system based on the flywheel energy storage array. Owing to the advantages of fast response and frequent charge-discharge characteristics, the flywheel system can be used to support and regulate the power grid through the process of the frequency and amplitude modulation. By using the flywheel system, the stability of the power grid can be improved effectively. In this paper, the proposed power regulation system is firstly introduced as well as the working principle of the flywheel energy storage array. On this basis, the key performance indices of the flywheel array are given, and then a kind of charge-discharge test process is provided. Finally, the power experiments by using the actual flywheel system is developed, including the power absorption and feedback electric generation. The experiment results show that the response characteristics, capacity and power of the designed flywheel array can meet the needs of power regulation system applied in the power grid.
Abstract: Due to a larger intervention application of the wind-photovolatic new energy generation system, the stability and reliability of the main power grid will be greatly affected. One of the most effective methods to improve the quality of the power grid is to add the energy storage euipment. Based in this, according to the energy storage demand of shor...
Show More
