This study developed an energy management system (EMS) via internet-of-things (IOT) for lighting control on a university campus in Taiwan. The system structure of EMS was composed of five layers: a network layer using WebAccess, an application layer using software and controllers, a control layer using remote I/O, an equipment layer using the lighting equipment, and a perception layer using light sensors. The proposed system for lighting control on a university campus was completed successfully and running smoothly online. This study provides valuable reference in engineering and technology education employed in training and development programs.
This study develops a novel method for learning mechatronics using remote monitoring and control, based on a programmable logic controller (PLC) and WebAccess. A mechatronics module, a Web-CAM and a PLC were integrated with WebAccess software to organize a remote laboratory. The proposed system enables users to access the Internet for remote monitoring and control of the mechatronics module via a web browser, thereby enhancing work flexibility by enabling personnel to control mechatronics equipment from a remote location. Mechatronics control and long-distance monitoring were realized by establishing communication between the PLC and WebAccess. Analytical results indicate that the proposed system is feasible. The suitability of this system is demonstrated in the department of industrial education and technology at National Changhua University of Education, Taiwan. Preliminary evaluation of the system was encouraging and has shown that it has achieved success in helping students understand concepts and master remote monitoring and control techniques.
This study investigated the performance of a single-stage scroll compressed air source heat pump coupled with a flash tank indirect vapor injection. In the refrigerant circulating piping of the heat pump, an indirect vapor injection piping connecting a flash tank at the refrigerant outlet of a condenser and the suction of a scroll compressor was designed. By the indirect refrigerant vapor injection from the flash tank, the saturation pressure and temperature of the refrigerant (R134a) in the evaporator can be raised and the sub-cooling of the refrigerant at the inlet of expansion valve can be enlarged as well. Thus, energy consumption of the compressor can be reduced and cooling capacity of the evaporator can be boosted. It was found that the suitable amount of indirect vapor refrigerant strongly depends on the operational environmental temperatures. By adjusting the suitable indirect vapor injection volume into the compressor, the performance of the heat pump was enhanced. In this study, a suitable indirect vapor injection volume was found and 5~15% performance increments can be obtained while the heat pump operated under ambient temperatures in a range from 5°C to 35°C.
Wearable cuffless photoplethysmographic blood pressure monitors have garnered widespread attention in recent years; however, the long-term performance values of these devices are questionable. Most cuffless blood pressure monitors require initial baseline calibration and regular recalibrations with a cuffed blood pressure monitor to ensure accurate blood pressure estimation, and their estimation accuracy may vary over time if left uncalibrated. Therefore, this study assessed the accuracy and long-term performance of an upper-arm, cuffless photoplethysmographic blood pressure monitor according to the ISO 81060-2 standard. This device was based on a nonlinear machine-learning model architecture with a fine-tuning optimized method. The blood pressure measurement protocol followed a validation procedure according to the standard, with an additional four weekly blood pressure measurements over a 1-month period, to assess the long-term performance values of the upper-arm, cuffless photoplethysmographic blood pressure monitor. The results showed that the photoplethysmographic signals obtained from the upper arm had better qualities when compared with those measured from the wrist. When compared with the cuffed blood pressure monitor, the means ± standard deviations of the difference in BP at week 1 (baseline) were −1.36 ± 7.24 and −2.11 ± 5.71 mmHg for systolic and diastolic blood pressure, respectively, which met the first criterion of ≤5 ± ≤8.0 mmHg and met the second criterion of a systolic blood pressure ≤ 6.89 mmHg and a diastolic blood pressure ≤ 6.84 mmHg. The differences in the uncalibrated blood pressure values between the test and reference blood pressure monitors measured from week 2 to week 5 remained stable and met both criteria 1 and 2 of the ISO 81060-2 standard. The upper-arm, cuffless photoplethysmographic blood pressure monitor in this study generated high-quality photoplethysmographic signals with satisfactory accuracy at both initial calibration and 1-month follow-ups. This device could be a convenient and practical tool to continuously measure blood pressure over long periods of time.
This study sought to identify the competency requirements for students in electrical engineering, specifically those that are needed for the design of touch screen interfaces. Using the Hybrid Behaviorally Anchored Rating Scale, this study drew on expert opinion to formulate a list of competencies, and empirically tested the validity and relevance of this list through a survey distributed to a separate group of experts. We identified 36 competencies considered essential for effective performance design of touch screen interfaces in electrical engineering. This study provides a valuable reference to educators in the field of engineering and technology who are involved in training and development programs.
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