Search results

1 – 10 of over 2000
Article
Publication date: 15 November 2019

Li Xiong, Xinguo Zhang and Yan Chen

The ammeter can measure the direct current and low-frequency alternating current through the wires, but it is difficult to measure complex waveforms. The oscilloscope can measure…

120

Abstract

Purpose

The ammeter can measure the direct current and low-frequency alternating current through the wires, but it is difficult to measure complex waveforms. The oscilloscope can measure complex waveforms, but it is easy to measure the voltage waveform and difficult to measure the current waveform. Thus, how to measure complex current waveforms with oscilloscope is an important and crucial issue that needs to be solved in practical engineering applications. To solve the above problems, an active short circuit line method is proposed to measure the volt-ampere characteristic curve of chaotic circuits.

Design/methodology/approach

In this paper, an active short circuit line method is proposed to measure the volt-ampere characteristic curve of various chaotic circuits especially for memristive systems. A memristor-based chaotic system is introduced, and the corresponding memristor-based circuit is constructed and implemented by using electronic components.

Findings

The chaotic attractors and volt-ampere characteristic curve of the memristor-based chaotic circuit are successfully analyzed and verified by oscilloscope measurement with the proposed active short circuit line method. Accordingly, the hardware circuit experiments are carried out to validate the effectiveness and feasibility of the active short circuit line method for these chaotic circuits. A good agreement is shown between the numerical simulations and the experimental results.

Originality/value

The primary contributions of this paper are as follows: an active short circuit line method for measuring the volt-ampere characteristic curve of chaotic circuits is proposed for the first time. A memristor-based chaotic system is also constructed by using memristor as nonlinear term. Then, the active short circuit line method is applied to measure the volt-ampere characteristic curve of the corresponding memristor-based chaotic circuit.

Article
Publication date: 28 January 2020

Xiang Li, Zhijun Li and Zihao Wen

This paper aims to introduce a novel 4D hyperchaotic fractional-order system which can produce one-to-four-wing hyperchaotic attractors. In the study of chaotic systems with…

Abstract

Purpose

This paper aims to introduce a novel 4D hyperchaotic fractional-order system which can produce one-to-four-wing hyperchaotic attractors. In the study of chaotic systems with variable-wing attractors, although some chaotic systems can generate one-to-four-wing attractors, none of them are hyperchaotic attractors, which is incomplete for the dynamic characteristics of chaotic systems.

Design/methodology/approach

A novel 4D fractional-order hyperchaotic system is proposed based on the classical three-dimensional Lü system. The complex and abundant dynamic behaviors of the fractional-order system are analyzed by phase diagrams, bifurcation diagrams and the corresponding Lyapunov exponents. In addition, SE and C0 algorithms are used to analyze the complexity of the fractional-order system. Then, the influence of order q on the system is also investigated. Finally, the circuit is implemented using physical components.

Findings

The most particular interest is that the system can generate one-to-four-wing hyperchaotic attractors with only one parameter variation. Then, the hardware circuit experimental results tally with the numerical simulations, which proves the validity and feasibility of the fractional-order hyperchaotic system. Besides, under different initial conditions, coexisting attractors can be obtained by changing the parameter d or the order q. Then, the complexity analysis of the system shows that the fractional-order chaotic system has higher complexity than the corresponding integer-order chaotic system.

Originality/value

The circuit structure of the fractional-order hyperchaotic system is simple and easy to implement, and one-to-four-wing hyperchaotic attractors can be observed in the circuit. To the best of the knowledge, this unique phenomenon has not been reported in any literature. It is of great reference value to analysis and circuit realization of fractional-order chaotic systems.

Details

Circuit World, vol. 46 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Open Access
Article
Publication date: 31 January 2020

Vinícius Rosa Cota, Cleiton Lopes Aguiar, Bezamat de Souza Neto and Miguel Benegas

The purpose of this paper is to argue in favor of the open hardware philosophy (open-source hardware – OSH) as a technological innovation and academic entrepreneurshipmodel in…

1792

Abstract

Purpose

The purpose of this paper is to argue in favor of the open hardware philosophy (open-source hardware – OSH) as a technological innovation and academic entrepreneurshipmodel in Brazil.

Design/methodology/approach

This argument is based on three pillars. The first one refers to a bibliographic review of theoretical frameworks related to academic entrepreneurship and technological innovation to emphasize the disruptive innovation capacity of academia. Second, a few elements related to the Brazilian political, economic and structural scenario, which entail a (more) favorable environment to technological innovation and academic entrepreneurship, is presented. Finally, concepts related to OSH and its business model are approached to demonstrate the facilitating effect toward the whole process.

Findings

As a result of the argument made herein, it is possible to perceive the viability of the OSH model in terms of entrepreneurship and technological innovation in the academic sphere, and to perceive its benefits before social and economic needs in areas such as health and education.

Research limitations/implications

There are no empirical or quantifiable data in the literature that enable comparison between OSH and traditional technological innovation models.

Originality/value

The considerations on the philosophical value of OSH and its business models are scarcely explored in international literature. As far as we know, relating OSH to technological innovation entrepreneurship in the academic sphere, as well as its singularities in Brazil regarding the innovation national system and social and economic demands, is a unique approach in literature.

Details

Innovation & Management Review, vol. 17 no. 2
Type: Research Article
ISSN: 2515-8961

Keywords

Article
Publication date: 23 August 2018

Yoel Raban and Aharon Hauptman

The cyber security industry emerged rapidly in recent years due to mounting cyber threats and increasing cyber hacking activities. Research on emerging technologies emphasizes the…

2484

Abstract

Purpose

The cyber security industry emerged rapidly in recent years due to mounting cyber threats and increasing cyber hacking activities. Research on emerging technologies emphasizes the risks and sometimes neglects to address the potential positive contribution to cyber security. The purpose of this study is to conduct a relatively balanced long-term foresight study to elicit major significant threat drivers and to identify emerging technologies that are likely to have a significant impact on defense and attack capabilities in cyber security.

Design/methodology/approach

The main instruments used in this study were horizon scanning and an online survey among subject-matter experts that assessed emerging threats and the potential impact of several emerging technologies on cyber defense capabilities and cyber attack capabilities.

Findings

An expert survey shows that cyber resilience, homomorphic encryption and blockchain may be considered as technologies contributing mainly to defense capabilities. On the other hand, Internet of Things, biohacking and human machine interface (HMI) and autonomous technologies add mainly to attack capabilities. In the middle, we find autonomous technologies, quantum computing and artificial intelligence that contribute to defense, as well as to attack capabilities, with roughly similar impact on both.

Originality/value

This study adds to the current research a balanced long-term view and experts’ assessment of negative and positive impacts of emerging technologies, including their time to maturity and consensus levels. Two new Likert scale measures were applied to measure the potential impact of emerging technologies on cyber security, thus enabling the classification of the results into four groups (net positive, net negative, positive-positive and negative-negative).

Details

foresight, vol. 20 no. 4
Type: Research Article
ISSN: 1463-6689

Keywords

Article
Publication date: 1 June 2000

George K. Chako

Briefly reviews previous literature by the author before presenting an original 12 step system integration protocol designed to ensure the success of companies or countries in…

7203

Abstract

Briefly reviews previous literature by the author before presenting an original 12 step system integration protocol designed to ensure the success of companies or countries in their efforts to develop and market new products. Looks at the issues from different strategic levels such as corporate, international, military and economic. Presents 31 case studies, including the success of Japan in microchips to the failure of Xerox to sell its invention of the Alto personal computer 3 years before Apple: from the success in DNA and Superconductor research to the success of Sunbeam in inventing and marketing food processors: and from the daring invention and production of atomic energy for survival to the successes of sewing machine inventor Howe in co‐operating on patents to compete in markets. Includes 306 questions and answers in order to qualify concepts introduced.

Details

Asia Pacific Journal of Marketing and Logistics, vol. 12 no. 2/3
Type: Research Article
ISSN: 1355-5855

Keywords

Article
Publication date: 1 March 2013

Y.B. Liao, X. Han, Z.J. Zhu, Y. Wang and S. Kang

With the rapid development of integrated circuits, verification of SOC chips has become a great challenge due to its integration and complexity. Traditional software‐based…

Abstract

Purpose

With the rapid development of integrated circuits, verification of SOC chips has become a great challenge due to its integration and complexity. Traditional software‐based simulation methodology cannot meet verification needs. Therefore, FPGA‐based hardware acceleration technologies are requested in SOC verification. The classic methodology of hardware acceleration downloads the DUT (Device under Test) to the FPGA, while part of RTL codes and test bench is still run on the simulator in the workstation. Research found that the speed bottleneck of this methodology is mostly caused by the ping‐pong mode of data transmission between workstation software and the FPGA emulator, thus resulting in that channel transmission time takes too much proportion of total time. The purpose of this paper is to present a vector mode based hardware/software co‐emulation methodology, which leverages a pipeline structure to transmit, receive and buffer data. This methodology reduces the communication overhead by carrying out a parallel mechanism in that while user's design is under test in the emulator, signal data are transmitting in the channel simultaneously, thus increasing the speed of hardware acceleration and emulation.

Design/methodology/approach

The methodology of hardware acceleration proposed by this paper intercepts data for once from the emulation process of a traditional platform as test bench and utilizes direct memory access (DMA) channel to speed up data transfer, as well as increasing reasonable data caching mechanism, which reduces the ratio of channel transmission time in the entire emulation time, achieving accelerating emulation.

Findings

The proposed methodology and traditional hardware acceleration approach were tested on a quasi‐cyclic low‐density parity‐check (LDPC) decoder. Experiment results indicate that the proposed method can increase communication throughput 140 times compared with the traditional approach.

Originality/value

A vector mode based hardware/software co‐emulation methodology is presented in the paper. Higher communication throughput can be achieved by carrying out a parallel mechanism, as well as leveraging a pipeline structure to transmit, receive and buffer data.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 4 July 2018

Yanjun Lu, Li Xiong, Yongfang Zhang, Peijin Zhang, Cheng Liu, Sha Li and Jianxiong Kang

This paper aims to introduce a novel four-dimensional hyper-chaotic system with different hyper-chaotic attractors as certain parameters vary. The typical dynamical behaviors of…

Abstract

Purpose

This paper aims to introduce a novel four-dimensional hyper-chaotic system with different hyper-chaotic attractors as certain parameters vary. The typical dynamical behaviors of the new hyper-chaotic system are discussed in detail. The control problem of these hyper-chaotic attractors is also investigated analytically and numerically. Then, two novel electronic circuits of the proposed hyper-chaotic system with different parameters are presented and realized using physical components.

Design/methodology/approach

The adaptive control method is derived to achieve chaotic synchronization and anti-synchronization of the novel hyper-chaotic system with unknown parameters by making the synchronization and anti-synchronization error systems asymptotically stable at the origin based on Lyapunov stability theory. Then, two novel electronic circuits of the proposed hyper-chaotic system with different parameters are presented and realized using physical components. Multisim simulations and electronic circuit experiments are consistent with MATLAB simulation results and they verify the existence of these hyper-chaotic attractors.

Findings

Comparisons among MATLAB simulations, Multisim simulation results and physical experimental results show that they are consistent with each other and demonstrate that changing attractors of the hyper-chaotic system exist.

Originality/value

The goal of this paper is to construct a new four-dimensional hyper-chaotic system with different attractors as certain parameters vary. The adaptive synchronization and anti-synchronization laws of the novel hyper-chaotic system are established based on Lyapunov stability theory. The corresponding electronic circuits for the novel hyper-chaotic system with different attractors are also implemented to illustrate the accuracy and efficiency of chaotic circuit design.

Details

Circuit World, vol. 44 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 January 1986

J.M. Kallis, A.H. Samuels and R.P. Stout

Great savings can be achieved by detecting and isolating design problems early in an electronic programme. Many design problems, including electrical overstress, poor thermal…

Abstract

Great savings can be achieved by detecting and isolating design problems early in an electronic programme. Many design problems, including electrical overstress, poor thermal design and circuit layout problems, are detectable by their infrared (I‐R) signature. A reliability and design improvement tool utilising current I‐R scanning technology has been developed. Specifically, an I‐R scanning method for making accurate temperature measurements for the purpose of electronic design reliability improvement and qualification has been developed and verified experimentally. Field‐actual conditions, in which radiative and convective heat losses from the components are negligible, are simulated with a thermally insulating enclosure. The enclosure is designed for rapid removal just before the scan, obviating the need for exotic materials that are transparent to I‐R in the scanner's passband. With typical hardware thermal lags, the method allows determination of true temperatures simulating field conditions. Corrections for unwanted scanner‐produced radiation and for the target emissivity are made with a three‐scan method and specially designed apparatus. An integral part of this apparatus is the aforementioned quickly removable thermal enclosure. The three scans take approximately an hour for a typical circuit board after initial set‐up time. True‐temperature measurements of circuit boards can be made with the I‐R design improvement tool now.

Details

Circuit World, vol. 12 no. 2
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 6 May 2020

Poornima Sridharan and Pugazhendhi Sugumaran C.

An annual substation equipment failure report says 3/7 capacitive voltage transformer (CVT) got damaged because of ferroresonance overvoltage. The conventional mitigation circuit

Abstract

Purpose

An annual substation equipment failure report says 3/7 capacitive voltage transformer (CVT) got damaged because of ferroresonance overvoltage. The conventional mitigation circuit fails to protect the transformer as the overvoltage may fall in the range between 2 and 4 per unit. It is necessary to develop a device to suppress the overvoltage as well as overcurrent of the CVT. This study aims to propose the suitability of memristor emulator as a mitigation circuit for ferroresonance.

Design/methodology/approach

The literature implies that a nonlinear circuit can protect the transformer against ferroresonance. An attempt is made with a memristor emulator using Operational Amplifier (OPAMP) for the mitigation of ferroresonance in a prototype transformer. The circuit is simulated using PSpice and validated for its ideal characteristics using hardware implementation. The nonlinear memductance is designed which is required to mitigate the ferroresonance. The mitigation performance has been compared with conventional method along with fast Fourier transform (FFT) analysis.

Findings

While the linear resistor recovers the secondary voltage by 74.1%, the memristor emulator does it by 82.05% during ferroresonance. Also, the total harmonic distortion (THD) of ferroresonance signal found to be 22.06% got improved as 2.56% using memristor emulator.

Research limitations/implications

The suitability of memristor emulator as a mitigation circuit for ferroresonance is proposed in this paper. As ferroresonance occurs in instrument transformers which have extra high voltage (EHV) rated primary windings and (110 V/[110 V/1.732]) rated secondary windings, the mitigation device is proposed to be connected as a nonlinear load across the secondary windings of the transformer. This paper discusses the preliminary work of ferroresonance mitigation in a prototype transformer. The mitigation circuit may have memristor or meminductor for ferroresonance mitigation when they are commercially available in future.

Practical implications

The electronic component-based memristor emulator may not work at 110 V practically as they may be rated at low power. Hence, chemical component-based memristor emulator was developed to do the same. The authors like to clarify that the memristor will be a solution for ferroresonance in future not the memristor emulator circuit.

Social implications

With the real form of memristor, the transistor world will be replaced by it and may have a revolution in the field of electronics, VLSI, etc. This contribution attempts to project the use of memristor in a smaller scale in high-voltage engineering.

Originality/value

The electronic component-based memristor emulator is proposed as a mitigation circuit for ferroresonance. The hypothesis has been verified successfully in a prototype transformer. Testing circuit of memristor emulator involves transformer, practically. The mitigation performance has been compared with conventional method technically and justified with FFT analysis.

Details

Circuit World, vol. 47 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 9 August 2011

Yavuz Şenol, Taner Akkan, Ender Yazgan Bulgun and Ozan Kayacan

The purpose of this paper is to realize an electronic circuit design on the fabric surfaces to form a fully integrated functional active T‐shirt structure.

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Abstract

Purpose

The purpose of this paper is to realize an electronic circuit design on the fabric surfaces to form a fully integrated functional active T‐shirt structure.

Design/methodology/approach

Functional products combining textile, electronics and the software have attracted great attention in recent years. The integration of the electrical and electronic devices on the garment surface using conductive threads is a challenging issue considering conductiveness, long durability, washability and manufacturing process. As an application, a group of light emitting diode (LED) lights controlled by a light sensor, accelerometer and related electronic control circuits were placed on a fabric construction.

Findings

The brightness of LED lights is controlled by using a light sensor depending on the perceived ambient light intensity. LED lighting patterns are controlled by means of an accelerometer which senses the physical activities of the wearer, such as walking, running and standing.

Originality/value

In this study, new construction methods have been successfully implemented and the active T‐shirt has been realized with its related hardware and software.

Details

International Journal of Clothing Science and Technology, vol. 23 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

1 – 10 of over 2000