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Article
Publication date: 13 April 2015

Fee Hilbert, Julia Barth, Julia Gremm, Daniel Gros, Jessica Haiter, Maria Henkel, Wilhelm Reinhardt and Wolfgang G. Stock

The purpose of this paper is to show how the coverage of publications is represented in information services. Academic citation databases (Web of Science, Scopus, Google…

Abstract

Purpose

The purpose of this paper is to show how the coverage of publications is represented in information services. Academic citation databases (Web of Science, Scopus, Google Scholar) and scientific social media (Mendeley, CiteULike, BibSonomy) were analyzed by applying a new method: the use of personal publication lists of scientists.

Design/methodology/approach

Personal publication lists of scientists of the field of information science were analyzed. All data were taken in collaboration with the scientists in order to guarantee complete publication lists.

Findings

The demonstrated calibration parameter shows the coverage of information services in the field of information science. None of the investigated databases reached a coverage of 100 percent. However Google Scholar covers a greater amount of publications than other academic citation databases and scientific social media.

Research limitations/implications

Results were limited to the publications of scientists working at an information science department from 2003 to 2012 at German-speaking universities.

Practical implications

Scientists of the field of information science are encouraged to review their publication strategy in case of quality and quantity.

Originality/value

The paper confirms the usefulness of personal publication lists as a calibration parameter for measuring coverage of information services.

Details

Online Information Review, vol. 39 no. 2
Type: Research Article
ISSN: 1468-4527

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Article
Publication date: 9 November 2012

Ademola O. Kaka, Mehmet Toycan, Vali Bashiry and Stuart D. Walker

The purpose of this paper is to describe a modified Hilbert‐based fractal antenna for ultra wideband (UWB) wireless applications. Simulation results show excellent…

Abstract

Purpose

The purpose of this paper is to describe a modified Hilbert‐based fractal antenna for ultra wideband (UWB) wireless applications. Simulation results show excellent multi‐band characteristics for UWB wireless applications.

Design/methodology/approach

A Hilbert curve‐based fractal is optimised for self‐replicating, space‐filling and self‐avoiding properties. In the proposed design, the Hilbert curve is applied to a rectangle as an initial iteration and maintained for the later iterations. Additionally, a Yagi‐like strip is removed from the second iteration of the Hilbert patch and a hexagonal portion is removed from the substrate to achieve good optimization. The antenna feed is created through a micro‐strip line with a feeding section. Finally, a partial ground plane technique is used for improved impedance matching characteristics. A finite element method (FEM) is used to simulate the modified Hilbert model with commercially available Ansoft HFSS software.

Findings

The proposed antenna is miniaturized (39 mm length×30 mm width) and has multi‐band characteristics. The simulation results show that the antenna has a reflection coefficient characteristic of <−10 dB, a linear phase reflection coefficient, better than 65 percent radiation efficiency, 2.2‐4 dBi antenna gain and nearly omni‐directional radiation pattern properties over the UWB bandwidth (3.1‐10.6 GHz).

Originality/value

The antenna shows promising characteristics for the full 7.5 GHz UWB bandwidth. In addition, the performance is achieved by using laceration techniques on the Hilbert patch and substrate, respectively. A partial ground plane ensures impedance matching of 50 over full UWB bandwidth. The simulation analysis of the modified Hilbert fractal antenna design constitutes the main contribution of the paper.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 6
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 6 July 2015

Ademola O. Kaka, Mehmet Toycan and Stuart D. Walker

A vertically stacked, three layer hybrid Hilbert fractal geometry and serpentine radiator-based patch antenna is proposed and characterized for medical implant…

Abstract

Purpose

A vertically stacked, three layer hybrid Hilbert fractal geometry and serpentine radiator-based patch antenna is proposed and characterized for medical implant applications at the Industrial, Scientific and Medical band (2.4-2.48 GHz). Antenna parameters are optimised to achieve miniaturized, biocompatible and stable transmission characteristics. The paper aims to discuss these issues.

Design/methodology/approach

Human tissue effects on the antenna electrical characteristics were simulated with a three-layer (skin, fat and muscle) human tissue model with the dimensions of 180×70×60 mm3 (width×height×thickness mm3). Different stacked substrates are utilized for the satisfactory characteristics. Two identical radiating patches are printed on Roger 3,010 (ε r=10.2) and Alumina (ε r=9.4) substrate materials, respectively. In addition, various superstrate materials are considered and simulated to prevent short circuit the antenna while having a direct contact with the metallization, and achieve biocompatibility. Finally, superstrate material of Zirconia (ε r=29) is used to achieve biocompatibility and long-life. A finite element method is used to simulate the proposed hybrid model with commercially available Ansoft HFSS software.

Findings

The antenna is miniaturized, having dimensions of 10×8.4×2 mm3 (width×height×thickness mm3). The resonance frequency of the antenna is 2.4 GHz with a bandwidth of 100 MHz at return loss (S11) of better than −10 dB characteristics. Overall, the proposed antenna have 50 Ω impedance matching, −21 dB far field antenna gain, single-plane omni-directional radiation pattern properties and incident power of 5.3 mW to adhere Specific Absorption Rate regulation limit.

Originality/value

Vertically stacked three layer hybrid design have miniaturized characteristics, wide bandwidth, biocompatible, and stable characteristics in three layer human tissue model make this antenna suitable for implant biomedical monitor systems. The advanced simulation analysis of the proposed design constitutes the main contribution of the paper.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 9 October 2019

Sunil Kumar Tumma and Bheema Rao Nistala

The purpose of this paper is to design an on-chip inductor with high inductance, high-quality factor and high self-resonance frequency for the equivalent on-chip area…

Abstract

Purpose

The purpose of this paper is to design an on-chip inductor with high inductance, high-quality factor and high self-resonance frequency for the equivalent on-chip area using fractal curves.

Design/methodology/approach

A novel hybrid series stacked differential fractal inductor using Hilbert and Sierpinski fractal curves is proposed with two different layers connected in series using vias. The inductor is implemented in Sonnet EM simulator using 180 nm CMOS standard process technology.

Findings

The proposed inductor reduces the parasitic capacitance and negative mutual inductance between the adjacent layers with significant improvement in overall inductance, quality factor and self-resonance frequency when compared with conventional series stacked fractal inductors.

Research limitations/implications

The fractal inductor is used to create high inductance in the single-layer process, but access to multilayers is restricted owing to unusual and expensive fabrication processes.

Practical implications

The proposed inductor can be used in implementation of low noise amplifier, voltage controlled oscillators and power amplifiers.

Originality/value

This paper introduces a combination of two fractal curves to implement a hybrid fractal inductor that enhances the performance of the inductor.

Details

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

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Article
Publication date: 26 February 2019

Saddam Bensaoucha, Sid Ahmed Bessedik, Aissa Ameur and Ali Teta

The purpose of this study aims to focus on the detection and identification of the broken rotor bars (BRBs) of a squirrel cage induction motor (SCIM). The presented…

Abstract

Purpose

The purpose of this study aims to focus on the detection and identification of the broken rotor bars (BRBs) of a squirrel cage induction motor (SCIM). The presented diagnosis technique is based on artificial neural networks (NNs) that use as inputs the results of the spectral analysis using the fast Fourier transform (FFT) of the reduced Park’s vector modulus (RPVM), along with the load values in which the motor operates.

Design/methodology/approach

First, this paper presents a comparative study between FFT applied on Hilbert modulus, Park’s vector modulus and RPVM to extract feature frequencies of BRB faults. Moreover, the extracted features of FFT applied to RPVM and the load values were selected as NNs’ inputs for the detection of the number of BRBs.

Findings

The obtained simulation results using MATLAB (Matrix Laboratory) environment show the effectiveness and accuracy of the proposed NNs based approach.

Originality/value

The current paper presents a novel diagnostic method for BRBs’ fault detection in SCIM, based on the combination between the signal processing analysis (FFT of RPVM) and artificial intelligence (NNs).

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 20 June 2016

Sajan Kapil, Prathamesh Joshi, Hari Vithasth Yagani, Dhirendra Rana, Pravin Milind Kulkarni, Ranjeet Kumar and K.P. Karunakaran

In additive manufacturing (AM) process, the physical properties of the products made by fractal toolpaths are better as compared to those made by conventional toolpaths…

Abstract

Purpose

In additive manufacturing (AM) process, the physical properties of the products made by fractal toolpaths are better as compared to those made by conventional toolpaths. Also, it is desirable to minimize the number of tool retractions. The purpose of this study is to describe three different methods to generate fractal-based computer numerical control (CNC) toolpath for area filling of a closed curve with minimum or zero tool retractions.

Design/methodology/approach

This work describes three different methods to generate fractal-based CNC toolpath for area filling of a closed curve with minimum or zero tool retractions. In the first method, a large fractal square is placed over the outer boundary and then rest of the unwanted curve is trimmed out. To reduce the number of retractions, ends of the trimmed toolpath are connected in such a way that overlapping within the existing toolpath is avoided. In the second method, the trimming of the fractal is similar to the first method but the ends of trimmed toolpath are connected such that the overlapping is found at the boundaries only. The toolpath in the third method is a combination of fractal and zigzag curves. This toolpath is capable of filling a given connected area in a single pass without any tool retraction and toolpath overlap within a tolerance value equal to stepover of the toolpath.

Findings

The generated toolpath has several applications in AM and constant Z-height surface finishing. Experiments have been performed to verify the toolpath by depositing material by hybrid layered manufacturing process.

Research limitations/implications

Third toolpath method is suitable for the hybrid layered manufacturing process only because the toolpath overlapping tolerance may not be enough for other AM processes.

Originality/value

Development of a CNC toolpath for AM specifically hybrid layered manufacturing which can completely fill any arbitrary connected area in single pass while maintaining a constant stepover.

Details

Rapid Prototyping Journal, vol. 22 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 22 October 2019

Yuri Merizalde, Luis Hernández-Callejo, Oscar Duque-Pérez and Víctor Alonso-Gómez

Despite the wide dissemination and application of current signature analysis (CSA) in general industry, CSA is not commonly used in the wind industry, where the use of…

Abstract

Purpose

Despite the wide dissemination and application of current signature analysis (CSA) in general industry, CSA is not commonly used in the wind industry, where the use of vibration signals predominates. Therefore, the purpose of this paper is to review the use of generator CSA (GCSA) in the online fault detection and diagnosis of wind turbines (WTs).

Design/methodology/approach

This is a bibliographical investigation in which the use of GCSA for the maintenance of WTs is analyzed. A section is dedicated to each of the main components, including the theoretical foundations on which GCSA is based and the methodology, mathematical models and signal processing techniques used by the proposals that exist on this topic.

Findings

The lack of appropriate technology and mathematical models, as well as the difficulty involved in performing actual studies in the field and the lack of research projects, has prevented the expansion of the use of GCSA for fault detection of other WT components. This research area has yet to be explored, and the existing investigations mainly focus on the gearbox and the doubly fed induction generator; however, modern signal treatment and artificial intelligence techniques could offer new opportunities in this field.

Originality/value

Although literature on the use of GCSA for the detection and diagnosis of faults in WTs has been published, these papers address specific applications for each of the WT components, especially gearboxes and generators. For this reason, the main contribution of this study is providing a comprehensive vision for the use of GCSA in the maintenance of WTs.

Details

Journal of Quality in Maintenance Engineering, vol. 26 no. 3
Type: Research Article
ISSN: 1355-2511

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Article
Publication date: 1 April 1974

Smedleys Ltd v. Breed effectively disposes of Section 3 (3), Food and Drugs Act, 1955 as a defence in law in what nowadays constitutes the commonest source of all food…

Abstract

Smedleys Ltd v. Breed effectively disposes of Section 3 (3), Food and Drugs Act, 1955 as a defence in law in what nowadays constitutes the commonest source of all food prosecutions, viz., foreign matter in food. Their Lord‐ships' judgment is indeed a brilliant exposition of the law on the subject, but the result of their dismissal of the appeal can only be seen, as one of their number stated, that local authorities and magistrates for all practical purposes can ignore the subsection, and from the numerous reports of legal proceedings, this is what they have been doing for many years. It was resurrected in a case, similar in circumstance to that in Smedleys, a couple of years ago, in respect of a snail in black currant jam, in which the snail and black currants were identical in size and appearance.

Details

British Food Journal, vol. 76 no. 4
Type: Research Article
ISSN: 0007-070X

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Case study
Publication date: 20 January 2017

Russell Walker

In March 2007 C. James Prieur, CEO of insurance provider Conseco, was faced with a crisis. The front page of the New York Times featured a story on the grieving family of…

Abstract

In March 2007 C. James Prieur, CEO of insurance provider Conseco, was faced with a crisis. The front page of the New York Times featured a story on the grieving family of an elderly woman who had faithfully paid for her Conseco long-term care (LTC) policy, only to find that it would not pay her claims. Her family had to pay for her care (until her recent death), which unfortunately resulted in the loss of the family business. The family was now very publicly pursuing litigation. For a company that depended on thousands of employees, investors, and independent agents who sold the insurance plans, this reputational risk was a serious threat. On top of this immediate crisis, all signs in the industry were pointing to the fact that the LTC business itself was not viable, yet over the years Conseco had acquired a number of LTC insurance providers. Students are asked to analyze not only what Prieur’s priorities should be in addressing the immediate crisis but also the risks inherent in the LTC industry and how this might affect Conseco’s success as a business moving forward

After reading and analyzing the case, students will be able to:

  • Analyze the risks in the long-term care insurance industry

  • Distinguish the various types of risk that caused a company’s crisis and recognize the potential for contagion

  • Brainstorm how the risks faced by Conseco could have been avoided or better contained

  • Recommend the first steps C. James Prieur and the Conseco leadership team should take to rectify the New York Times article crisis

Analyze the risks in the long-term care insurance industry

Distinguish the various types of risk that caused a company’s crisis and recognize the potential for contagion

Brainstorm how the risks faced by Conseco could have been avoided or better contained

Recommend the first steps C. James Prieur and the Conseco leadership team should take to rectify the New York Times article crisis

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Book part
Publication date: 12 June 2017

Ofer Sharone

The rapid growth of online social networking sites (“SNS”) such as LinkedIn and Facebook has created new forms of online labor market intermediation that are reconfiguring…

Abstract

The rapid growth of online social networking sites (“SNS”) such as LinkedIn and Facebook has created new forms of online labor market intermediation that are reconfiguring the hiring process in profound ways; yet, little is understood about the implications of these new technologies for job seekers navigating the labor market, or more broadly, for the careers and lives of workers. The existing literature has focused on digital inequality – workers’ unequal access to or skilled use of digital technologies – but has left unanswered critical questions about the emerging and broad effects of SNS as a labor market intermediary. Drawing on in-depth interviews with unemployed workers this paper describes job seekers’ experiences using SNS to look for work. The findings suggest that SNS intermediation of the labor market has two kinds of effects. First, as an intermediary for hiring, SNS produces labor market winners and losers involving filtering processes that often have little to do with evaluations of merit. Second, SNS filtering processes exert new pressures on all workers, whether winners or losers as perceived though this new filter, to manage their careers, and to some extent their private lives, in particular ways that fit the logic of the SNS-mediated labor market.

Details

Emerging Conceptions of Work, Management and the Labor Market
Type: Book
ISBN: 978-1-78714-459-0

Keywords

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