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Article
Publication date: 2 January 2018

Rahis Kumar Yadav, Pankaj Pathak and R.M. Mehra

This paper aims to report small-signal parameter extraction and simulation of enhanced dual-channel dual-material gate AlGaN/GaN high electron mobility transistor (HEMT…

Abstract

Purpose

This paper aims to report small-signal parameter extraction and simulation of enhanced dual-channel dual-material gate AlGaN/GaN high electron mobility transistor (HEMT) for the first time for the characterization of a device in microwave range of frequency.

Design/methodology/approach

For parameter extraction, a standard and well-known direct parameter extraction methodology is applied. Extrinsic elements of small-signal circuit model are extracted from measured S-parameters obtained using pinch-off cold field effect transistor (FET) biasing in the first step at a low frequency range and at a higher frequency range in the second step to ensure higher extraction accuracy. Intrinsic elements are extracted from intrinsic Y-parameters that are obtained after de-embedding all the extrinsic parasitic elements of the device. Figure of merits of radio frequency are also derived from the measured results and S-parameters of the proposed device.

Findings

Small signal parameters of the proposed device circuit model are extracted using the standard direct parameter extraction technique. Analysis of microwave figure of merits for device include maximum oscillation frequency, cut-off frequency, current gain, transducer power gain, available power gain, maximum stable gain, transconductance, drain conductance, stern stability factor and time delay.

Practical implications

The paper bridges the gaps between theory and experimental practices by validating extracted results with reported results of structurally matching devices.

Originality/value

An enhanced device structure investigated for small signal parameters incorporates field plate over dual metal engineered gate to provide better electric field uniformity, effective suppression of short channel effect, reduction in current collapse, improvement in carrier transport efficiency and enhancement in drain current capabilities.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 7 November 2019

Sk Abdul Kaium, Sayed Abul Hossain and Jafar Sadak Ali

The purpose of this paper is to highlight that the need for improved system identification methods within the domain of modal analysis increases under the impulse of the…

Abstract

Purpose

The purpose of this paper is to highlight that the need for improved system identification methods within the domain of modal analysis increases under the impulse of the broadening field of applications, e.g., damage detection and vibro-acoustics, and the increased complexity of today’s structures. Although significant research efforts during the last two decades have resulted in an extensive number of parametric identification algorithms, most of them are certainly not directly applicable for modal parameter extraction. So, based on this, the aim of the present work is to develop a technique for modal parameter extraction from the measured signal.

Design/methodology/approach

A survey and classification of the different modal analysis methods are made; however, the focus of this thesis is placed on modal parameter extraction from measured time signal. Some of the methods are examined in detail, including both single-degree-of-freedom and multi-degree-of-freedom approaches using single and global frequency-response analysis concepts. The theory behind each of these various analysis methods is presented in depth, together with the development of computer programs, theoretical and experimental examples and discussion, in order to evaluate the capabilities of those methods. The problem of identifying properties of structures that possess close modes is treated in particular detail, as this is a difficult situation to handle and yet a very common one in many structures. It is essential to obtain a good model for the behavior of the structure in order to pursue various applications of experimental modal analysis (EMA), namely: updating of finite element models, structural modification, subsystem-coupling and calculation of real modes from complex modes, to name a few. This last topic is particularly important for the validation of finite element models, and for this reason, a number of different methods to calculate real modes from complex modes are presented and discussed in this paper.

Findings

In this paper, Modal parameters like mode shapes and natural frequencies are extracted using an FFT analyzer and with the help of ARTeMiS, and subsequently, an algorithm has been developed based on frequency domain decomposition (FDD) technique to check the accuracy of the results as obtained from ARTeMiS. It is observed that the frequency domain-based algorithm shows good agreement with the extracted results. Hence the following conclusion may be drawn: among several frequency domain-based algorithms for modal parameter extraction, the FDD technique is more reliable and it shows a very good agreement with the experimental results.

Research limitations/implications

In the case of extraction techniques using measured data in the frequency domain, it is reported that the model using derivatives of modal parameters performed better in many situations. Lack of accurate and repeatable dynamic response measurements on complex structures in a real-life situation is a challenging problem to analyze exact modal parameters.

Practical implications

During the last two decades, there has been a growing interest in the domain of modal analysis. Evolved from a simple technique for troubleshooting, modal analysis has become an established technique to analyze the dynamical behavior of complex mechanical structures. Important examples are found in the automotive (cars, trucks, motorcycles), railway, maritime, aerospace (aircrafts, satellites, space shuttle), civil (bridges, buildings, offshore platforms) and heavy equipment industry.

Social implications

Presently structural health monitoring has become a significantly important issue in the area of structural engineering particularly in the context of safety and future usefulness of a structure. A lot of research is being carried out in this area incorporating the modern sophisticated instrumentations and efficient numerical techniques. The dynamic approach is mostly employed to detect structural damage, due to its inherent advantage of having global and location-independent responses. EMA has been attempted by many researchers in a controlled laboratory environment. However, measuring input excitation force(s) seems to be very expensive and difficult for the health assessment of an existing real-life structure. So Ambient Vibration Analysis is a good alternative to overcome those difficulties associated with the measurement of input excitation force.

Originality/value

Three single bay two storey frame structure has been chosen for the experiment. The frame has been divided into six small elements. An algorithm has been developed to determine the natural frequency of those frame structures of which one is undamaged and the rest two damages in single element and double element, respectively. The experimental results from ARTeMIS and from developed algorithm have been compared to verify the effectiveness of the developed algorithm. Modal parameters like mode shapes and natural frequencies are extracted using an FFT analyzer and with the help of ARTeMiS, and subsequently, an algorithm has been programmed in MATLAB based on the FDD technique to check the accuracy of the results as obtained from ARTeMiS. Using singular value decomposition, the power Spectral density function matrix is decomposed using the MATLAB program. It is observed that the frequency domain-based algorithm shows good consistency with the extracted results.

Details

International Journal of Structural Integrity, vol. 11 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 9 May 2019

Sawinder Kaur, Paramjit S. Panesar, Sushma Gurumayum, Prasad Rasane and Vikas Kumar

The extraction of bioactive compounds such as pigments from natural sources, using different solvents, is a vital downstream process. The present study aims to investigate…

115

Abstract

Purpose

The extraction of bioactive compounds such as pigments from natural sources, using different solvents, is a vital downstream process. The present study aims to investigate the effect of different variables, namely, extraction temperature, mass of fermented rice and time on the extraction process of orevactaene and flavanoid pigment from Epicoccum nigrum fermented broken rice.

Design/methodology/approach

Central composite rotatable design under response surface methodology was used for deducing optimized conditions. The pigments were extracted under conditions of extraction temperature (40-70°C), mass of fermented rice (0.5-1.5 g) and time (30-90 min), using water as the extraction media. The experimental data obtained were studied by analysis of variance. Data were fitted to a second-order polynomial equation using multiple regression analysis.

Findings

The optimum conditions generated by the software for aqueous extraction process, i.e. extraction temperature of 55.7°C, 0.79 g of fermented matter and extraction time of 56.6 min, resulted in a pigment yield of 52.7AU/g orevactaene and 77.2 AU/g flavanoid.

Research limitations/implications

The developed polynomial empirical model for the optimal recovery of the orevactaene and flavanoid pigments could be used for further studies in prediction of yield under specified variable conditions.

Practical implications

The response surface methodology helped in optimizng the conditions for the eco-friendly low-cost aqueous extarction process for orevactaene and flavanoid pigments, produced by Epicoccum nigrum during solid state fermentation of broken rice. This optimization can provide the basis for scaling up for industrial extraction process.

Originality/value

This paper focuses on optimizing the extraction conditions to get the maximum yield of orevactaene and flavanoid pigments, using water as the extracting media. No literature is available on the optimization of the extraction process of Epicoccum nigrum pigments, to the best of the authors’ knowledge.

Details

Pigment & Resin Technology, vol. 48 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 February 1987

H. HADDARA and S. CRISTOLOVEANU

The effect of stress induced defects on the ohmic region characteristics of short channel MOSFETs is analyzed by means of a two dimensional device simulator. The device…

Abstract

The effect of stress induced defects on the ohmic region characteristics of short channel MOSFETs is analyzed by means of a two dimensional device simulator. The device aging is summarized in the formation of a narrow defective interface region whose nature, length and position above the channel are the parameters of our investigation. The channel conductance and transconductance degradations were found to be greatly influenced by the position of the defective region and its length. Also, fundamental differences were observed between the effects of interface states and fixed oxide charges. The interaction between the defective and defect‐free channel regions was found to produce a transconductance overshoot which attenuates the aging effects. Finally, a parameter extraction method based on a two‐piece analytical model of locally damaged MOSFETs is elaborated and validated by means of a 2‐D simulation.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 6 no. 2
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 8 May 2009

G.C. Pesenti and H. Boudinov

The purpose of this paper is to compare different junctions' parameters extraction models.

233

Abstract

Purpose

The purpose of this paper is to compare different junctions' parameters extraction models.

Design/methodology/approach

I‐V curves of p+n and pwelln diodes were measured. Five models for parameters extraction on I‐V characteristics of diodes in an educational poly‐Si gate pwell complementary metal oxide semiconductor (CMOS) technology were applied. The junctions' areas were 30 × 30 μm for the source‐body p+n junction of the PMOS transistor and 220 × 250 μm for the pwell‐body junction. The diodes were sintered in forming gas (10 percent of H2) in the temperature interval of 450‐525°C for times from 30 min up to 4 h.

Findings

It was shown that the best annealing regimes are different for both kinds of junctions.

Originality/value

The paper shows that the best annealing regime for p+n diodes (the lowest n and I0 values) is 450°C, 30 min and for the pwelln diodes (the lowest I0 values) is 525°C, 60 min. So, for the different kinds of junctions in one integrated circuit, different annealings could give the best parameters and the optimization depends on the specific characteristics of the developed technology.

Details

Microelectronics International, vol. 26 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 27 July 2012

Diana Grineviciute, Sigitas Krauledas and Matas V. Gutauskas

The purpose of this research is to perform instrumental comparison of hand parameters of knitted fabrics produced from different biodegradable fibres and to analyze…

Abstract

Purpose

The purpose of this research is to perform instrumental comparison of hand parameters of knitted fabrics produced from different biodegradable fibres and to analyze peculiarities of hand parameters' extent influenced by fabric structure and chemical softening.

Design/methodology/approach

The hand of five types of different biodegradable fabrics was evaluated. Experiments were performed using a method based on the principle of specimen biaxial punching deformation when a disc‐shaped specimen is extracted through a round nozzle. The Influence of fabric weave (terry and plain jersey) and finishing (padding with the silicone softener “Belfasin SI”) on the fabric hand was investigated.

Findings

Investigations have shown that weave type and finishing significantly influenced fabric hand properties. It was also stated that even tenuous differences between fabric parameters could be obtained by one numeral value of complex hand rate Q.

Practical implications

Experiments have shown that KTU–Griff–Tester is a simple, reliable instrumental device suitable to obtain quantitative information about fabric mechanical properties. Evaluation of finishing influence on a fabric hand could be precisely expressed by one parameter Q.

Originality/value

In the present research quantitative evaluation of new fabrics from biodegradable fibres hand was performed. Comparison between new biodegradable and traditional cotton fabrics has shown that new biodegradable fibres which are generally used for underwear, sportswear and for medical application are characterized by soft hand, as a result a good affinity with skin.

Details

International Journal of Clothing Science and Technology, vol. 24 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 27 June 2008

Soo‐Young Suk and Hyun‐Yeol Chung

The purpose of this paper is to describe a speech and character combined recognition engine (SCCRE) developed for working on personal digital assistants (PDAs) or on…

Abstract

Purpose

The purpose of this paper is to describe a speech and character combined recognition engine (SCCRE) developed for working on personal digital assistants (PDAs) or on mobile devices. Also, the architecture of a distributed recognition system for providing a more convenient user interface is discussed.

Design/methodology/approach

In SCCRE, feature extraction for speech and for character is carried out separately, but the recognition is performed in an engine. The client recognition engine essentially employs a continuous hidden Markov model (CHMM) structure and this CHMM structure consists of variable parameter topology in order to minimize the number of model parameters and to reduce recognition time. This model also adopts the proposed successive state and mixture splitting (SSMS) method for generating context independent model. SSMS optimizes the number of mixtures through splitting in mixture domain and the number of states through splitting in time domain.

Findings

The recognition results show that the developed engine can reduce the total number of Gaussian up to 40 per cent compared with the fixed parameter models at the same recognition performance when applied to speech recognition for mobile devices. It shows that SSMS can reduce the size of memory for models to 65 per cent and that for processing to 82 per cent. Moreover, the recognition time decreases 17 per cent with the SMS model while maintaining the recognition rate.

Originality/value

The proposed system will be very useful for many on‐line multimodal interfaces such as PDAs and mobile applications.

Details

International Journal of Pervasive Computing and Communications, vol. 4 no. 2
Type: Research Article
ISSN: 1742-7371

Keywords

Open Access
Article
Publication date: 30 July 2019

Zhizhou Wu, Yiming Zhang, Guishan Tan and Jia Hu

Traffic density is one of the most important parameters to consider in the traffic operation field. Owing to limited data sources, traditional methods cannot extract…

1050

Abstract

Purpose

Traffic density is one of the most important parameters to consider in the traffic operation field. Owing to limited data sources, traditional methods cannot extract traffic density directly. In the vehicular ad hoc network (VANET) environment, the vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) interaction technologies create better conditions for collecting the whole time-space and refined traffic data, which provides a new approach to solving this problem.

Design/methodology/approach

On that basis, a real-time traffic density extraction method has been proposed, including lane density, segment density and network density. Meanwhile, using SUMO and OMNet++ as traffic simulator and network simulator, respectively, the Veins framework as middleware and the two-way coupling VANET simulation platform was constructed.

Findings

Based on the simulation platform, a simulated intersection in Shanghai was developed to investigate the adaptability of the model.

Originality/value

Most research studies use separate simulation methods, importing trace data obtained by using from the simulation software to the communication simulation software. In this paper, the tight coupling simulation method is applied. Using real-time data and history data, the research focuses on the establishment and validation of the traffic density extraction model.

Details

Journal of Intelligent and Connected Vehicles, vol. 2 no. 1
Type: Research Article
ISSN: 2399-9802

Keywords

Article
Publication date: 1 April 2006

S. Kanerva and A. Arkkio

To provide a general method for coupled simulation of electrical machines and circuits, using finite element analysis and a circuit/system simulator.

Abstract

Purpose

To provide a general method for coupled simulation of electrical machines and circuits, using finite element analysis and a circuit/system simulator.

Design/methodology/approach

The electrical machine is modelled by dynamic inductance and electromotive force (EMF), which are determined by finite element analysis and updated in time‐stepping procedure. Calculation of these parameters is based on current perturbations that are applied on linearized field equations after determining the operating point by nonlinear analysis.

Findings

Based on the case studies, the presented method can be utilized in coupled field‐circuit simulation and the results correlate with those obtained by other known methods. The results were also validated according to experimental data.

Research limitations/implications

Calculation of the EMF and the presented implementation for SIMULINK have some limitations regarding the accuracy and stability of the numerical integration. In the future, the numerical methods could be still improved and the implementations could be extended to other simulators.

Practical implications

Since the presented methodology is of a general type, the research provides means to include field‐circuit coupling into a variety of different simulation software.

Originality/value

Definitions of the circuit parameters differ from the conventional ones, as a result of which the parameter extraction can be performed in computation‐effective way. The benefits of the research are met widely, since the general‐purpose methodology is not limited to any single software.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 11 May 2010

Aleksandar B. Menićanin, Mirjana S. Damnjanović and Ljiljana D. Živanov

The appropriate selection of a testing method largely determines the accuracy of a measurement. Parasitic effects associated with test fixture demand a significant…

Abstract

Purpose

The appropriate selection of a testing method largely determines the accuracy of a measurement. Parasitic effects associated with test fixture demand a significant consideration in a measurement. The purpose of this paper is to introduce a measurement procedure which can be used for the characterization of surface mount devices (SMD) components, especially devoted to SMD inductors.

Design/methodology/approach

The paper describes measurement technique, characterization, and extracting parameters of SMD components for printed circuit board (PCB) applications. The commercially available components (multi‐layer chip SMD inductors in the ceramic body) are measured and characterized using a vector network analyzer E5071B and adaptation test fixture on PCB board. Measurement results strongly depend on the choice of the PCB; the behaviour of the component depends on the environment where the component is placed.

Findings

The equivalent circuit parameters are extracted in closed form, from an accurate measurement of the board‐mounted SMD inductor Sparameters, without the necessity for cumbersome optimization procedures, which normally follow the radio frequency circuit synthesis.

Originality/value

It this paper, a new adaptation test fixture in PCB technology is realized. It is modeled and it has provided the extraction of parameters (intrinsic and extrinsic) of SMD inductor with great accuracy.

Details

Microelectronics International, vol. 27 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

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