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Article
Publication date: 20 January 2012

Mahanth Prasad, R.P. Yadav, V. Sahula and V.K. Khanna

The purpose of this paper is to help reduce power consumption by using platinum‐based microhotplate with different dielectric membranes SiO2 and Si3N4 for gas sensing…

Abstract

Purpose

The purpose of this paper is to help reduce power consumption by using platinum‐based microhotplate with different dielectric membranes SiO2 and Si3N4 for gas sensing applications, and to develop platinum lift‐off process using DC sputtering method for fabrication of platinum resistor.

Design/methodology/approach

Semiconductor gas sensors normally require high power consumption because of their elevated operating temperature 300‐600°C. Considering the thermal resistant and sensitive characteristics of metal platinum as well as heat and electricity insulating characteristics of SiO2, Si3N4 and combination of both, a kind of the Si‐substrate microhotplate was designed and simulated using ANSYS 10.0 tool. Thermal oxidation of Si wafer was carried out to get a 1.0 μm thick SiO2 layer. Pt deposition on oxidized silicon substrate by lift‐off was carried out using DC sputtering technique.

Findings

The platinum‐based microhotplate requires 31.3‐70.5 mW power to create the temperature 348‐752°C for gas sensing applications. The SiO2 membrane can operate the gas sensitive film at higher temperature than the Si3N4 and combination of both the membranes at same power consumption. The paper also presents the FEM simulation of different heating elements like nichrome and tantalum and its comparison to platinum for microhotplate applications.

Originality/value

Both the simulation and experimental work provides the low cost, high yield and repeatability in realization of microhotplate. The design and simulation work provides the better selection of heating elements and dielectric membranes. The developed experimental process provides the easy fabrication of platinum resistors using DC sputtering technique.

Details

Sensor Review, vol. 32 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 18 September 2018

Xueling Liang and Yong Chen

Internet of Things (IoT) has been widely adopted in the commercial sector. Although IoT enables traditional libraries to convert into digital ones, the implementation of…

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Abstract

Purpose

Internet of Things (IoT) has been widely adopted in the commercial sector. Although IoT enables traditional libraries to convert into digital ones, the implementation of the IoT in libraries is slow. The purpose of this paper is to report on the current state of research on applications of IoT in libraries, describe challenges that IoT applications face in libraries and discus directions of adopting IoT in libraries in the future.

Design/methodology/approach

To conduct this research, the literature of IoT and its application in libraries were reviewed by examining existing literature in Institute of Electrical and Electronics Engineers (IEEE) Xplore.

Findings

The literature review finds that radio-frequency identification has been adopted by digital libraries. The slow implementation of IoT is caused by security and privacy issues, lack of standards and the lack of financial, technological and organizational resources. This study provides a prospective for the application of IoT in libraries; the technologies of IoT have the potential in betterment of library services.

Research limitations/implications

The limitation of this study is that only IEEE Xplore is included. Other database should be explored in future research.

Originality/value

The application of IoT in libraries is an emerging issue; a systematic and extensive review of recent research on applications of IoT in libraries is unavailable. This paper presents an overview of IoT in libraries, findings and potential research opportunities.

Details

Library Hi Tech, vol. 38 no. 1
Type: Research Article
ISSN: 0737-8831

Keywords

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Article
Publication date: 3 December 2020

Yanmei Huang, Changrui Deng, Xiaoyuan Zhang and Yukun Bao

Despite the widespread use of univariate empirical mode decomposition (EMD) in financial market forecasting, the application of multivariate empirical mode decomposition…

Abstract

Purpose

Despite the widespread use of univariate empirical mode decomposition (EMD) in financial market forecasting, the application of multivariate empirical mode decomposition (MEMD) has not been fully investigated. The purpose of this study is to forecast the stock price index more accurately, relying on the capability of MEMD in modeling the dependency between relevant variables.

Design/methodology/approach

Quantitative and comprehensive assessments were carried out to compare the performance of some selected models. Data for the assessments were collected from three major stock exchanges, namely, the standard and poor 500 index from the USA, the Hang Seng index from Hong Kong and the Shanghai Stock Exchange composite index from China. MEMD-based support vector regression (SVR) was used as the modeling framework, where MEMD was first introduced to simultaneously decompose the relevant covariates, including the opening price, the highest price, the lowest price, the closing price and the trading volume of a stock price index. Then, SVR was used to set up forecasting models for each component decomposed and another SVR model was used to generate the final forecast based on the forecasts of each component. This paper named this the MEMD-SVR-SVR model.

Findings

The results show that the MEMD-based modeling framework outperforms other selected competing models. As per the models using MEMD, the MEMD-SVR-SVR model excels in terms of prediction accuracy across the various data sets.

Originality/value

This research extends the literature of EMD-based univariate models by considering the scenario of multiple variables for improving forecasting accuracy and simplifying computability, which contributes to the analytics pool for the financial analysis community.

Details

Journal of Systems and Information Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1328-7265

Keywords

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Article
Publication date: 3 January 2017

Peyman Rafiee, Golta Khatibi and Michael Zehetbauer

The purpose of this paper is to provide an overview of the major reliability issues of microelectromechanical systems (MEMS) under mechanical and environmental loading…

Abstract

Purpose

The purpose of this paper is to provide an overview of the major reliability issues of microelectromechanical systems (MEMS) under mechanical and environmental loading conditions. Furthermore, a comprehensive study on the nonlinear behavior of silicon MEMS devices is presented and different aspects of this phenomenon are discussed.

Design/methodology/approach

Regarding the reliability investigations, the most important failure aspects affecting the proper operation of the MEMS components with focus on those caused by environmental and mechanical loads are reviewed. These studies include failures due to fatigue loads, mechanical vibration, mechanical shock, humidity, temperature and particulate contamination. In addition, the influence of squeeze film air damping on the dynamic response of MEMS devices is briefly discussed. A further subject of this paper is discussion of studies on the nonlinearity of silicon MEMS. For this purpose, after a description of the basic principles of nonlinearity, the consequences of nonlinear phenomena such as frequency shift, hysteresis and harmonic generation and their effects on the device performance are reviewed. Special attention is paid to the mode coupling effect between the resonant modes as a result of energy transfer because of the nonlinearity of silicon. For a better understanding of these effects, the nonlinear behavior of silicon is demonstrated by using the example of Si cantilever beams.

Findings

It is shown that environmental and mechanical loads can influence on proper operation of the MEMS components and lead to early fracture. In addition, it is demonstrated that nonlinearity modifies dynamic response and leads to new phenomena such as frequency shift and mode coupling. Finally, some ideas are given as possible future areas of research works.

Originality/value

This is a review paper and aimed to review the latest manuscripts published in the field of reliability and nonlinearity of the MEMS structures.

Details

Microelectronics International, vol. 34 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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