Designing a Partly Self-Powered Keyboard Based on Triboelectric Effect

The purpose of this paper is to design a keyboard using the triboelectric effect (Tribo Electric Nano Generator - TENG) to collect a part of the energy from keystrokes to reduce the power consumption of the keyboard. Using elastic material as the cover on the keyboard to maximize the capture of energy from typing. The keyboard layers are made from common materials such as Al (Aluminum) and PTFE (Polytetrafluoroethylene). The built-in 16-button keyboard ensures the same typing speed as a typical keyboard. Based on selected triboelectric material, the output voltage of keyboard was simulated and processed by using a signal detection circuit. The results show that the average voltage generated by each key with electrical friction effect is about 4 V, the power consumption for the detection circuit is about 0.32 W. In addition, the keystroke signals were sent and displayed correctly on the designed software on the computer.

A Study on Multi-Hop Routing Scheme for Wireless Sensor Networks

Wireless sensor networks (WSN) play an important role in IoT (Internet of Things) as an interconnecting infrastructure. Working with a limited energy source, the vital challenge for WSN is to prolong the network lifetime as an important performance metric. Furthermore, the limitations of regular transmission technologies create localized network areas of a multi-hop fashion form that adds more constraints to enhance the network performance. Hence, the clustering strategies initially have solved these problems and received the attention of many studies, an approach using unequal clustering strategy has yielded some positive results since consumed energy gaps are avoided in regions near base stations. However, the routing strategy among cluster heads in multi-hop wireless networks is still a big challenge because of its inefficiency in energy consumption aspects. Therefore, in this paper, we propose a novel method that combining an unequal clustering problem and a simple multi-hop routing to prolong network life. The numerical results show that the proposed solution is more effective than other models in recent studies

Experimental Characterization of Drag Coefficient of an UAV Recovery Parachute

Parachute recovery systems are proved to be an efficient method to recovery and rescue unmanned aerial vehicles (UAV) as it follows most requirements of reliability and airworthiness in flights. Parachutes are key components of the recovery systems and the drag coefficient of parachutes plays a crucial role in evaluating parachute’s performance. The purpose of the research is to determine and compare the impact of some factors on aerodynamic drag force during the inflation of a parachute. The canopy’s shape (flat circular type and extended skirt 10% flat type), of the length of suspension lines (be in proportion to nominal diameter from 0.6 to 1.5) are considered. Measurement of the drag force of the parachute models is carried out in an open return wind tunnel. Experimental results show that flat circular canopy has a higher drag coefficient than extended skirt 10% flat model in the range of low speed from 3 to 6 m/s. However, when wind speed is greater than 6 m/s, the drag coefficients of both two parachute types are nearly 0.85. In terms of the suspension line, the longer length would significantly raise the coefficient of drag force.

Design and Implementation of a LoRa Communication System Supporting Edge Computing on the Smart Multi-Platform IoT Gateway

LoRa technology was developed over 10 years ago, with many communication protocols optimized for LoRaWAN. However, in the protocols, all data from the end devices are sent directly or forwarded through a gateway to the LoRaWAN server and processed centrally there. Accordingly, the gateway only acts as a forwarder. This mechanism increases the processing load on the server, increases latency, and is not suitable for applications with a large number of end devices or that require real-time applications. In this paper, we design and develop a new LoRa communication protocol that supports edge computing at the gateway. At the same time, the authors design and manufacture a Smart Multiplatform IoT Gateway (SMGW) and LoRa nodes that allow the implementation and evaluation of the proposed protocol in practice. The test results on a system of 50 LoRa nodes and the SMGW show that the proposed protocol works well when evaluating its performance in terms of reliability, latency, and power consumption. This proposed system is suitable for applications that require edge computing and is easily extendable to other IoT applications.

Researching and Development of an Autonomous Underwater Vehicles with Capability of Collecting Solar Energy

Autonomous Underwater Vehicles (AUV) is an unmanned underwater device with capability of performing a variety of missions in the water environment such as ocean operation, offshore waters, polluted water investigation including: marine scientific research, maritime monitoring, exploration, marine economics, oil and gas, security and defense, surveillance and measurement and in rescue and salve. In this article, the authors developed a model of AUV with retractable wings and evaluate the efficiency of solar energy collection. The establishment of the controller to adapt the stability requirements, in accordance with the model of equipment S-AUV (Solar - Autonomous Underwater Vehicles) was built. The hydrodynamic equations with the predefined conditions were modeled and solved. The Hierarchical Sliding Mode Controller (HSMC) for the S-AUV were applied in this research. Experimental results showed that the efficiency of the collection of the solar cell has been significantly improved comparing to a diving equipment without retractable energy wings. In addition, the simulation results showed that the developed controller performed much better control quality, adhering to the set value with the error within the permissible limit.

Monitoring and Control System for Heat Experimental Equipment of High-Speed Vertical Spindle Bearings

High speed of spindle for high-speed machining is the mission and development trend of today's machine tools. However, improper lubrication can cause a large temperature difference on the bearings, causing thermal deformation that affects the accuracy of the spindle. Heat experimental equipment for high-speed vertical spindle bearing is necessary. This paper presents a design and manufacture of control and monitoring system of heat experimental equipment for high-speed vertical spindle bearing based on PLC, WinCC and Webserver. This experimental device with supervisory control solution allows easy implementation of the test mode and data collection to plan out the appropriate lubrication mode. The system includes motor control and monitoring, observing of sensors, alarm and reporting at local and on site remotely. This solution can be applied to other industrial equipment to meet the needs of Industry 4.0.

A Study on the Effects of Plug Shape on Operating Performance of an Electric Pressure Regulator Applied for Gaseous Fueled Vehicles

A model-based study was conducted to examine the effects of plug shape on electromagnetic force and dynamic response of an electric pressure regulator (EPR) applied for gaseous fueled vehicles. Mathematical models were established to describe the operation of the EPR, including mechanical and electrical models. A two-dimensional (2D) symmetric model of the EPR was built in Maxwell software to simulate the electromagnetic force under the effects of plug shape. Afterward, the 2D symmetric model of EPR with the electromagnetic force calculated was imported into Simplorer software to simulate the dynamic response of the EPR based on the influence of plug shape. The shape of plug in the EPR was changed through the dimension parameters denoted by dimension (h) and slope angle (). The simulation results show that the electromagnetic force and dynamic response of the EPR can be optimized when h and  are selected at 3mm and 480, respectively.

Deep Learning-Based Approach for Diagnosis of COVID-19 Patients from CT Lung Images

COVID-19 is currently one of the most life-threatening problems around the world. The fast and accurate detection of the COVID-19 infection plays an important role in identifying, making better decisions as well as ensuring treatment for the patients. In this study, we propose an approach to identify COVID-19 patients via deep learning methods. The proposed approach includes two steps: segmentation of lung and classification of patients via analyzing the segmented images. Especially, in the first step, the attention gate is integrated into Unet neural network structure, which can help increase the accuracy of the segmentation tasks. In the second step, the EfficientNet-B4 is applied to classify COVID-19 patients. By using EfficientNet, the performance of the classification process as well as the size of the model are improved. We apply the proposed approach for the database including 130 patients. Experimental results show the desired performances of the proposed approach.

A Generalized Space Vector Modulation for Cascaded H-Bridge Inverters under Faulty Conditions

In this research, a new space vector modulation control algorithm is proposed to increase the reliability and the accuracy of the cascaded H-bridge multilevel inverters in case of faulty situations where one or several power cells do not function. When one or more switches of a cell are opened or shorted, that cell is considered faulty. By giving a detailed analysis on the impact of the faulty power cells on the voltage space vectors, the inapplicable voltage vectors are removed precisely. Consequently, the optimal redundant switching states are chosen such that the highest possible output voltage can be achieved. In addition, the balance of the three phases line-to-line voltage and current are maintained. The proposed algorithm is also generalized so that it can be applied to any level of H-bridge inverters. The validity of the method is verified by numerical simulations using MATLAB Simulink with an 11-level cascaded H-bridge inverter.

Designing SPI to I2C Protocol Converter Base on ASIC Technology and Implementing on the FPGA Platform

Nowadays embedded systems are using a lot of different communication standards to transfer data such as USB, UART, SPI, I2C, etc. To be able to transfer data with each communication standard, the system needs at least one controller block for that communication standard. This has added to the complexity of the system and the cost of manufacturing hardware. Embedded systems only support SPI communication if desired, which can still be communicated with peripherals with I2C standard. However, the SPI cannot be directly connected to the I2C but must use a standard communication converter. This paper will primarily focus on designing an IP core communication standard converter from SPI to I2C using APB (Advanced Peripheral Bus) communication as one of the AMBA (Advanced Microcontroller Bus Architecture) communication sets. In particular, APB is a bus used to communicate with peripherals that do not require fast processing speeds such as UART, SPI, I2C, etc.