Novel Semantic-Based Probabilistic Context Aware Approach for Situations Enrichment and Adaptation

This paper aims at ensuring an efficient recommendation. It proposes a new context-aware semantic-based probabilistic situations injection and adaptation using an ontology approach and Bayesian-classifier. The idea is to predict the relevant situations for recommending the right services. Indeed, situations are correlated with the user’s context. It can, therefore, be considered in designing a recommendation approach to enhance the relevancy by reducing the execution time. The proposed solution in which four probability-based-context rule situation items (user’s location and time, user’s role, their preferences and experiences) are chosen as inputs to predict user’s situations. Subsequently, the weighted linear combination is applied to calculate the similarity of rule items. The higher scores between the selected items are used to identify the relevant user’s situations. Three context parameters (CPU speed, sensor availability and RAM size) of the current devices are used to ensure adaptive service recommendation. Experimental results show that the proposed approach enhances accuracy rate with a high number of situations rules. A comparison with existing recommendation approaches shows that the proposed approach is more efficient and decreases the execution time.

Design and Experimental Research of Variable Formula Fertilization Control System Based on Prescription Diagram

In order to solve the problems such as the inability to automatically mix a variety of solid fertilizers and the unreasonable fertilizer amount, improve fertilizer utilization, and reduce production costs, this study designs a variable formula fertilization control system based on a prescription diagram, including pressure sensor, speed sensor, servo motor, fertilizer discharge actuator, Programmable Logic Controller (PLC controller), vehicle control terminal, etc. Based on pre-loaded soil prescription diagram and combining fertilizer pressure and ground wheel speed detection information, the system obtained a formula fertilization control strategy through calculation to realize the function of fast and automatic formula of nitrogen, phosphorus, and potassium fertilizers and precise variable fertilization. The experimental study on the performance of the variable formula fertilization control system showed the following: the measurement error range of the pressure sensor was 0.005~0.03%; the relationship between the motor speed and the amount of nitrogen, phosphorus, and potassium fertilizer discharged was calibrated. Three gears were established for the motor speed: low (10 r/min), medium (30 r/min), and high (50 r/min); the measurement accuracy of the speed sensor was above 98%. The test verified that the control accuracy of the variable formula fertilization system reached more than 95%, which met the requirements of fast automatic formula and precise variable fertilization and had good practicability and economy.

Three-Phase Induction Motor Speed Estimation Using Recurrent Neural Network Structure

In induction motor speed control method, the development of the field-oriented control (FOC) algorithm which can control torque and flux separately enables the motor to replace many roles of DC motors. Induction motor speed control can be done by using a close loop system which requires a speed sensor. Referring to the speed sensor weaknesses such as less accurate of the measurement, this is due to the placement of the sensor system that is too far from the control system. Therefore, a speed sensorless method was developed which has various advantages. In this study, the speed sensorless method using an artificial neural network with recurrent neural network (RNN) as speed observer on three-phase induction motor has been discussed. The RNN can maintain steady-state conditions against a well-defined set point speed, so that the observer is able and will be suitable if applied as input control for the motor drives. In this work, the RNN has successfully estimated the rotor flux of the induction motor in MATLAB R2019a simulation as about 0.0004Wb. As based on speed estimation error, the estimator used has produced at about 26.77%, 8.7% and 6.1% for 150rad/s, 200rad/s and 250rad/s respectively. The future work can be developed and improved by creating a prototype system of the induction motor to get more accurate results in real-time of the proposed RNN observer.

Sliding-Mode-Based Current and Speed Sensors Fault Diagnosis for Five-Phase PMSM

The present paper deals with an active fault-tolerant speed tracking of a five-phase permanent magnet synchronous motor with currents and speed sensor failures. The active fault tolerant control scheme, integrating a sliding mode observer and backstepping controllers, is proposed to provide a continuous drive operation of the five-phase permanent magnet synchronous motor, even during more than one sensor fault occurrence. The sliding mode observer is designed to generate the residual signal necessary for the detection stage, whereas speed and current backstepping controllers handle the operation of the five-phase permanent magnet synchronous motor thanks to their ability to consider the nonlinearities of the system model in generating a control law that is robust enough in healthy and faulty cases. Furthermore, the FTC strategy uses the information received from the fault-tolerant switching block in terms of the measured and the observed currents and speed signals. To gain the maximum benefit of the sliding mode observer’s robustness to random noises and its ease of implementation, the observed currents and speed of the five-phase permanent magnet synchronous motor have been estimated. The simulation results are conducted to show the effectiveness of the proposed FTC control scheme and to prove its high performance in fault detection and tolerant control for the five-phase permanent magnet synchronous motor, since it significantly outperforms the performance provided by traditional methods.

Prototype Automation of Air Conditioning Treatment in the Grinding Area Aneka Cocoa Based on IoT

A good work environment will affect the level of productivity of workers in a company. The operation of the refrigeration machine in the cocoa powder grinding area is very important in production. The indicators for the operation of the cooling machine are dust density, ambient temperature and wind speed. With control on the indicator will increase efficiency. In this study, the indicator is controlled with a GP2Y1010AUF0F dust sensor, a DHT22 temperature sensor, a DS18B20 sensor, and a wind speed sensor as sensor inputs. Furthermore, the sensor will be processed by the Node M CU ESP826 module. System output will be displayed on LED and android. The results of this study indicate the accuracy of the dust sensor is 96.12%, the DHT22 temperature sensor is 99.80%, the DS18B20 temperature sensor is 99.57% and the speed sensor is 95.89%. In this prototype, we can monitor the temperature of the air velocity of dust particles in the engine and the temperature of the engine cooler together and closely monitored.

RESULTS OF EXPERIMENTAL STUDIES OF THE USE OF A BRUSHLESS ELECTRIC MOTORIN SEEDING DEVICES OF ROW-CROP SEEDERS OF THE MS TYPE

This paper presents the data of comparative studies of the characteristics of the Mxus XF15R brushless elec-tric motor (rotation speed; consumed current, power and efficiency) depending on the maximum torque. The de-sign of the stand for studying the characteristics of the seeding process when using an electric drive of the seed-ing disc is presented; the key elements of the stand are: the seeding section, seeding disc, electric motor connect-ed to the seeding disc, the control unit, the source of rare-fied pressure, the seeding disc speed sensor and the seeding sensor. The technique of working with the stand and the procedure for setting it up are described. During the operation, the following indicators are taken into ac-count: control signal of the seeding disc drive; seeding disc and rotor revolutions, rpm; the number of the seed in the total volume from the moment of measurement; time between seeds falling, ms; vacuum, kPa; hole diameter, mm; reference time between the fall of adjacent seeds at a given rotational speed of the seeding disc, ms. During the experiment, it was found that with a value in the seed-ing chamber of 5 kPa, in the frequency range of the seed-ing disc from 17-100 rpm, the actual seeding rate was 3.28 pcs m, the number of twins in the seeding process was 8.17%, the number of gaps in the sowing process was 5.46%, and the deviation from the set rate was 5.2%. Thus, the electric drive of the seeding disc based on the brushless DC motor XF15R Mxus has shown its efficiency and may be used in the existing configuration of the MC type sowing device.

Factors Affecting Ion Thruster’s Performance

In this project, we investigated how ion thrusters produce propulsion and how the design of ion thrusters affects the performance of the thruster. In the experiment, we build a high voltage power supply (0- 50 kV) and foil rings to produce ion wind. When considering the design of the thruster, we focus on three variables: the volume of the space, where ions are produced and the electric field intensity. Thus, to investigate the first variable we made foil rings with different radius and change the distance between the ring and positive cathode. To determine the propulsion produced we use a speed sensor to determine the magnitude of the wind produced.

Analysis and Study of Designs of Sensing Elements of Speed Sensors Based on the Wiegand Effect

Speed sensors are used in various products and systems of mechanical engineering, instrument making, flight and rocket and space technology. At the same time, the main requirements for such sensors include a wide range of measured revolutions, from almost zero to several thousand revolutions per minute. Another requirement is a range of operating temperatures, ranging from cryogenic to temperatures of several hundred degrees. In this case, a prerequisite should be a generator method of conversion, in which energy is not consumed from the outside, but it is generated during the operation of the sensor. The principle of operation of the speed sensor is based on the magnetic pulse mode, in which a private hysteresis loop is formed. The generation of such a characteristic is possessed by mechanically and thermally treated wire made of cobalt-iron-vanadium alloy 52K9F of uniform composition. As a result, the wire acquires a composite magnetic structure consisting of an external hard magnetic layer - a shell, a central soft magnetic layer and an intermediate layer. The layers have different properties, due to which the hysteresis loops of the Wiegand wire have a complex shape. A distinctive feature of the loops is the presence of practically vertical sections of magnetization change - discontinuities corresponding to an abrupt change in the magnetization of the material. The large discontinuity on the loops arises due to the so-called "Barkhausen jump", caused by an almost ideal single magnetic domain stretched along the axis of the wire in its core.