International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

The wireless channel in an industrial environment behaves much differently when compared with wave propagation in home and office environments. This is due to the presence of significant noise and interference caused by large machinery and heavy multipath propagation effects induced by highly reflective structures. In this article, a comprehensive review of radio wave propagation in an industrial environment is presented. The reported channel models and measurement results, at different frequencies and link configurations, of path loss, noise, interference, multipath propagation, and time-varying channel conditions are discussed, and the factors that influence them are highlighted. In addition, open research issues on the propagation of radio waves in an industrial environment are identified.

Propagation Channel Characteristics of Industrial Wireless Sensor Networks [Wireless Corner]

Indoor air quality has been a matter of concern for the international scientific community. Public health experts, environmental governances, and industry experts are working to improve the overall health, comfort, and well-being of building occupants. Repeated exposure to pollutants in indoor environments is reported as one of the potential causes of several chronic health problems such as lung cancer, cardiovascular disease, and respiratory infections. Moreover, smart cities projects are promoting the use of real-time monitoring systems to detect unfavorable scenarios for enhanced living environments. The main objective of this work is to present a systematic review of the current state of the art on indoor air quality monitoring systems based on the Internet of Things. The document highlights design aspects for monitoring systems, including sensor types, microcontrollers, architecture, and connectivity along with implementation issues of the studies published in the previous five years (2015–2020). The main contribution of this paper is to present the synthesis of existing research, knowledge gaps, associated challenges, and future recommendations. The results show that 70%, 65%, and 27.5% of studies focused on monitoring thermal comfort parameters, CO2, and PM levels, respectively. Additionally, there are 37.5% and 35% of systems based on Arduino and Raspberry Pi controllers. Only 22.5% of studies followed the calibration approach before system implementation, and 72.5% of systems claim energy efficiency.

/pdf/indoor-air-quality-monitoring-systems-based-on-internet-of-18jzdrf4ax.pdf

Indoor Air Quality Monitoring Systems Based on Internet of Things: A Systematic Review.

iCBLS: An interactive case-based learning system for medical education.

Due to the explosive growth of wireless devices and wireless traffic, the spectrum scarcity problem is becoming more urgent in numerous Radio Frequency (RF) systems. At the same time, many studies have shown that spectrum resources allocated to various existing RF systems are largely underutilized. As a potential solution to this spectrum scarcity problem, spectrum sharing among multiple, potentially dissimilar RF systems has been proposed. However, such spectrum sharing solutions are challenging to develop due to the lack of efficient coordination schemes and potentially different PHY/MAC properties. In this paper, we investigate existing spectrum sharing methods facilitating coexistence of various RF systems. The cognitive radio technique, which has been the subject of various surveys, constitutes a subset of our wider scope. We study more general coexistence scenarios and methods such as coexistence of communication systems with similar priorities, utilizing similar or different protocols or standards, as well as the coexistence of communication and non-communication systems using the same spectral resources. Finally, we explore open research issues on the spectrum sharing methods as well as potential approaches to resolving these issues.

Spectrum sharing methods for the coexistence of multiple RF systems: A survey

Current lifestyles promote the development and advancement in wireless technologies, especially in Wireless Sensor Networks (WSN) due to its several benefits. WSN offers a low cost, low data rate, flexible routing, longer lifetime, and low-energy consumption suitable for unmanned and long term monitoring. Among huge WSN applications, some key applications are smart houses, environmental monitoring, military applications, and other monitoring applications. As a result, ubiquitous increase in the number of wireless devices occupying the 2.4GHz frequency band. This causes a dense wireless connection followed by interference problem to WSN in the 2.4GHz frequency band. WSN is most affected by the interference issue because it has a lower data rate and transmission power compared to WLAN. Despite efforts made by researchers, to the author's knowledge, the interference issue is still a major problem in wireless networks. This paper aims to review the coexistence and interference issues of existing wireless technologies in the 2.4GHz Industrial, Scientific and Medical (ISM) band.

Interference issues and mitigation method in WSN 2.4GHz ISM band: A survey

Seasonal crops require reliable storage conditions to protect the yield once harvested. For long term storage, controlling the moisture content level in grains is challenging because existing moisture measuring techniques are time-consuming and laborious as measurements are carried out manually. The measurements are carried out using a sample and moisture may be unevenly distributed inside the silo/bin. Numerous studies have been conducted to measure the moisture content in grains utilising dielectric properties. To the best of authors’ knowledge, the utilisation of low-cost wireless technology operating in the 2.4 GHz and 915 MHz ISM bands such as Wireless Sensor Network (WSN) and Radio Frequency Identification (RFID) have not been widely investigated. This study focuses on the characterisation of 2.4 GHz Radio Frequency (RF) transceivers using ZigBee Standard and 868 to 915 MHz UHF RFID transceiver for moisture content classification and prediction using Artificial Neural Network (ANN) models. The Received Signal Strength Indicator (RSSI) from the wireless transceivers is used for moisture content prediction in rice. Four samples (2 kg of rice each) were conditioned to 10%, 15%, 20%, and 25% moisture contents. The RSSI from both systems were obtained and processed. The processed data is used as input to different ANNs models such as Support Vector Machine (SVM), K-Nearest Neighbour (KNN), Random Forest, and Multi-layer Perceptron (MLP). The results show that the Random Forest method with one input feature (RSSI_WSN) provides the highest accuracy of 87% compared to the other four models. All models show more than 98% accuracy when two input features (RSSI_WSN and RSSI_TAG2) are used. Hence, Random Forest is a reliable model that can be used to predict the moisture content level in rice as it gives a high accuracy even when only one input feature is used.

https://www.mdpi.com/1424-8220/21/5/1875/pdf

RF-Based Moisture Content Determination in Rice Using Machine Learning Techniques.

The high voltage DC power supply widely used for space communication and for industry consist of multistage rectifier circuit. To produce 6KV output voltage, Cockroft-Walton multiplier circuits are applied by reducing number of stages from 1200 into 32 stages without using transformer. With the implementation of this technique, it can minimize the volume of the circuit to be integrated on a single chip and it also can reduce associated power loss in the circuit. By eliminating the transformer method, cost and size for making Cockroft-Walton Voltage Multiplier are reduced. Specification need to be considered for designing a multiplier is size of component must use within the range of expected load current and output voltage The details description of the simulation, design, development and implementation of this works are done using Cadence PSPICE software. Results are present in term of the performances and efficiency.

Design of DC high voltage and low current power supply using Cockroft-Walton (C-W) voltage multiplier

The advancement of Micro-Electro-Mechanical-Systems (MEMS), microcontroller technologies and the idea of Internet of Things (IoT) motivates the development of wireless modules (e.g. WiFi, Bluetooth, Zigbee, and LoRa) that are small and affordable. This paper aims to provide detailed information on the development of the LoRaFi board. The LoRaFi 1.0 is a multi-protocol communication board developed by Centre of Excellence for Advanced Sensor Technology (CEASTech). The board was developed for but not limited to monitor the indoor air quality. The board comprises two different wireless communication modules namely, Long-range technology (LoRa) and WiFi (using ESP8266). The board can be configured to communicate either using LoRa or WiFi or both. The board has been tested and the wireless communication operates successfully. Apart from LoRa, WiFi enables data to be forwarded to the cloud/server where the data can be stored for further data analysis. This helps provide users with real-time information on their smartphones or other applications. In the future, researchers will conduct tests to investigate the communication link quality. Newer version with reduced board size and additional wireless communication module will be developed in the future as to increase board flexibility and widen the range of applications that can use the board.

https://iopscience.iop.org/article/10.1088/1757-899X/318/1/012051/pdf

Design and Development of Multi-Transceiver Lorafi Board consisting LoRa and ESP8266-Wifi Communication Module

The number of patients that require medical assistance is increasing each day while staff-patient ratio is not balanced causing issues such as treatment delay and often leads to patient dissatisfaction. Besides that, healthcare devices are getting complex and challenging for it to be handled and interpreted personally by patient. Lack of staff and challenges in operating the medical devices not only affect patient in hospital but also caused problem to home care patients that require full attention and constant monitoring. This urges for a development of new method or technology. At present, Wireless Sensor Network (WSN) is gaining interest as one of the major components in enabling Internet of Things (IoT) since it offers low cost, low power monitoring besides reducing devices dependency on wires or cable. Although, WSN is initially developed for military application, nowadays, it is being integrated into various applications such as environmental monitoring, smart monitoring and agricultural monitoring....

Noraini Azmi

Papers

Interference issues and mitigation method in WSN 2.4GHz ISM band: A survey

RF-Based Moisture Content Determination in Rice Using Machine Learning Techniques.

Design of DC high voltage and low current power supply using Cockroft-Walton (C-W) voltage multiplier

Design and Development of Multi-Transceiver Lorafi Board consisting LoRa and ESP8266-Wifi Communication Module

Enabling IoT: Integration of wireless sensor network for healthcare application using Waspmote