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Article
Publication date: 7 February 2019

Gabriel S. Ferreira, Tulio O. Guedes, Lucas F. Melo, Márcio S. Gonçalves and Roberto Pimentel

In reinforced concrete (RC) structures, an evidence of damage is the presence of cracking. In order to evaluate the effect of damage on cracking pattern and natural…

Abstract

Purpose

In reinforced concrete (RC) structures, an evidence of damage is the presence of cracking. In order to evaluate the effect of damage on cracking pattern and natural frequency in RC slabs, two of such structures with different dimensions and reinforcement ratios were tested, in which cracks were induced through application of static load, followed by modal tests using impact excitation. The paper aims to discuss this issue.

Design/methodology/approach

The gradient of the fundamental natural frequency along the decay, the crack opening rate and also a global damage index based on changes of the fundamental natural frequency were evaluated.

Findings

The behaviour of the aforementioned gradient was distinct for both slabs, increasing monotonically with the cracking level for the slab with lowest reinforcement ratio, and increasing until 33 per cent of the collapse load and then decreasing afterwards for the slab with the highest ratio. Changes of the gradient were consistent with changes of the crack opening rate. Both results of gradient changes and cracking pattern brought evidence that the balance between open (old) and breathing (new) cracks differed between the slabs, and may be responsible for such differences.

Originality/value

Damage assessment in RC structures using vibration tests is mostly concentrated on beams. In this work, an advance is made by investigating slabs. The lack of a unique pattern of changes of the gradient implies that its absolute value is not generally suitable for the association with the damage level. However, the impact tests can be effectively used to detect early damage on slabs using this proposed parameter.

Details

International Journal of Structural Integrity, vol. 10 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 31 May 2013

Rajendra Machavaram and Shankar Krishnapillai

The purpose of this paper is to provide an effective and simple technique to structural damage identification, particularly to identify a crack in a structure. Artificial…

Abstract

Purpose

The purpose of this paper is to provide an effective and simple technique to structural damage identification, particularly to identify a crack in a structure. Artificial neural networks approach is an alternative to identify the extent and location of the damage over the classical methods. Radial basis function (RBF) networks are good at function mapping and generalization ability among the various neural network approaches. RBF neural networks are chosen for the present study of crack identification.

Design/methodology/approach

Analyzing the vibration response of a structure is an effective way to monitor its health and even to detect the damage. A novel two‐stage improved radial basis function (IRBF) neural network methodology with conventional RBF in the first stage and a reduced search space moving technique in the second stage is proposed to identify the crack in a cantilever beam structure in the frequency domain. Latin hypercube sampling (LHS) technique is used in both stages to sample the frequency modal patterns to train the proposed network. Study is also conducted with and without addition of 5% white noise to the input patterns to simulate the experimental errors.

Findings

The results show a significant improvement in identifying the location and magnitude of a crack by the proposed IRBF method, in comparison with conventional RBF method and other classical methods. In case of crack location in a beam, the average identification error over 12 test cases was 0.69 per cent by IRBF network compared to 4.88 per cent by conventional RBF. Similar improvements are reported when compared to hybrid CPN BPN networks. It also requires much less computational effort as compared to other hybrid neural network approaches and classical methods.

Originality/value

The proposed novel IRBF crack identification technique is unique in originality and not reported elsewhere. It can identify the crack location and crack depth with very good accuracy, less computational effort and ease of implementation.

Article
Publication date: 14 March 2016

Xiaoying Yu and Qi Liao

Passwords have been designed to protect individual privacy and security and widely used in almost every area of our life. The strength of passwords is therefore critical…

1920

Abstract

Purpose

Passwords have been designed to protect individual privacy and security and widely used in almost every area of our life. The strength of passwords is therefore critical to the security of our systems. However, due to the explosion of user accounts and increasing complexity of password rules, users are struggling to find ways to make up sufficiently secure yet easy-to-remember passwords. This paper aims to investigate whether there are repetitive patterns when users choose passwords and how such behaviors may affect us to rethink password security policy.

Design/methodology/approach

The authors develop a model to formalize the password repetitive problem and design efficient algorithms to analyze the repeat patterns. To help security practitioners to analyze patterns, the authors design and implement a lightweight, Web-based visualization tool for interactive exploration of password data.

Findings

Through case studies on a real-world leaked password data set, the authors demonstrate how the tool can be used to identify various interesting patterns, e.g. shorter substrings of the same type used to make up longer strings, which are then repeated to make up the final passwords, suggesting that the length requirement of password policy does not necessarily increase security.

Originality/value

The contributions of this study are two-fold. First, the authors formalize the problem of password repetitive patterns by considering both short and long substrings and in both directions, which have not yet been considered in past. Efficient algorithms are developed and implemented that can analyze various repeat patterns quickly even in large data set. Second, the authors design and implement four novel visualization views that are particularly useful for exploration of password repeat patterns, i.e. the character frequency charts view, the short repeat heatmap view, the long repeat parallel coordinates view and the repeat word cloud view.

Details

Information & Computer Security, vol. 24 no. 1
Type: Research Article
ISSN: 2056-4961

Keywords

Article
Publication date: 12 October 2017

Claire de Motte, Di Bailey, Melanie Hunter and Alice L. Bennett

The purpose of this paper is to describe the pattern of self-harm (SH) and proven prison rule-breaking (PRB) behaviour in prisoners receiving treatment for personality…

Abstract

Purpose

The purpose of this paper is to describe the pattern of self-harm (SH) and proven prison rule-breaking (PRB) behaviour in prisoners receiving treatment for personality disorders (PDs) within a high security prison.

Design/methodology/approach

A comparative quantitative case study design supported the understanding of the frequency and pattern of SH and PRB behaviour across two stages of a PD treatment programme for 74 male prisoners. Data obtained from the prison’s records were analysed using dependent t-tests, χ2 test of independence and time-frequency analyses.

Findings

Inferential statistics showed that the frequency of SH and PRB behaviour statistically increased across two phases of the PD treatment programme; however, the method of SH or type of PRB behaviour engaged in did not change. Mapping the frequencies of incidents using a time-frequency analysis shows the patterns of both behaviours to be erratic, peaking in the latter phase of treatment, yet the frequency of incidents tended to decline over time.

Originality/value

This is the first study to explore SH and PRB behaviours in men across two phases of a PD treatment programme. This study highlights the need for continued psychological support alongside the PD treatment programme with a focus on supporting men in treatment to effectively manage their SH and PRB behaviour.

Details

Journal of Criminal Psychology, vol. 7 no. 4
Type: Research Article
ISSN: 2009-3829

Keywords

Article
Publication date: 1 February 1992

Ernst P. Billeter‐Frey

Analyses the economic system slice‐wise, taking the main economic activities for a year together. Within this slice the development of the economic activities is…

Abstract

Analyses the economic system slice‐wise, taking the main economic activities for a year together. Within this slice the development of the economic activities is characterized by plus or minus signs according to an increase or decrease of the activities. This yearly sequence of plus and minus signs is taken as a pattern. Analyses these economic patterns according to cybernetic and economic criteria. Sign‐equivalent patterns are taken together as groups. The chronological development of these groups gives the profiles of the economy. The development of profiles is quite concordant with the business cycle of the economy in question.

Details

Kybernetes, vol. 21 no. 2
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 23 August 2013

Auhood Alfaries, David Bell and Mark Lycett

The purpose of the research is to speed up the process of semantic web services by transformation of current Web services into semantic web services. This can be achieved…

Abstract

Purpose

The purpose of the research is to speed up the process of semantic web services by transformation of current Web services into semantic web services. This can be achieved by applying ontology learning techniques to automatically extract domain ontologies.

Design/methodology/approach

The work here presents a Service Ontology Learning Framework (SOLF), the core aspect of which extracts Structured Interpretation Patterns (SIP). These patterns are used to automate the acquisition (from production domain specific Web Services) of ontological concepts and the relations between those concepts.

Findings

A Semantic Web of accessible and re‐usable software services is able to support the increasingly dynamic and time‐limited development process. This is premised on the efficient and effective creation of supporting domain ontology.

Research limitations/implications

Though WSDL documents provide important application level service description, they alone are not sufficient for OL however, as: they typically provide technical descriptions only; and in many cases, Web services use XSD files to provide data type definitions. The need to include (and combine) other Web service resources in the OL process is therefore an important one.

Practical implications

Web service domain ontologies are the general means by which semantics are added to Web services; typically used as a common domain model and referenced by annotated or externally described Web artefacts (e.g. Web services). The development and deployment of Semantic Web services by enterprises and the wider business community has the potential to radically improve planned and ad‐hoc service re‐use. The reality is slower however, in good part because the development of an appropriate ontology is an expensive, error prone and labor intensive task. The proposed SOLF framework is aimed to overcome this problem by contributing a framework and a tool that can be used to build web service domain ontologies automatically.

Originality/value

The output of the SOLF process is an automatically generated OWL domain ontology, a basis from which a future Semantic Web Services can be delivered using existing Web services. It can be seen that the ontology created moves beyond basic taxonomy – extracting and relating concepts at a number of levels. More importantly, the approach provides integrated knowledge (represented by the individual WSDL documents) from a number of domain experts across a group of banks.

Article
Publication date: 12 October 2012

Tao Wang

Mining sequential patterns in large databases has become an important data mining task with broad applications, such as business analysis, web mining, security, and…

284

Abstract

Purpose

Mining sequential patterns in large databases has become an important data mining task with broad applications, such as business analysis, web mining, security, and bio‐sequences analysis. The purpose of this paper is to propose the notion of condensed frequent sequential pattern base (SP base) with guaranteed maximal error bound.

Design/methodology/approach

A subset of frequent sequential patterns is computed, and then used to approximate the supports of arbitrary frequent sequential patterns with guaranteed maximal error bound, because in many applications it is sufficient to generate only frequent sequential patterns with support frequency in close‐enough approximation instead of in full precision.

Findings

The concept of condensed frequent SP base is introduced, and an efficient algorithm for mining condensed SP bases is developed.

Research limitations/implications

A condensed frequent SP base can significantly reduce the set of sequential patterns that need to be mined, stored, and analyzed, while providing guaranteed error bound for frequencies of sequential patterns not in the base.

Practical implications

A much smaller base of patterns can help users to comprehend the mining results. Computing a much smaller pattern base also leads to better efficiency.

Originality/value

The paper shows that by adopting a novel pruning technology, the algorithm out‐performs the previous work by one order of magnitude.

Details

Kybernetes, vol. 41 no. 9
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 9 May 2022

Ajit Kumar Singh, Santosh Kumar Mahto and Rashmi Sinha

This study aims to present dual band reconfigurable MIMO antenna for 5G (sub-6 GHz) and WLAN applications.

Abstract

Purpose

This study aims to present dual band reconfigurable MIMO antenna for 5G (sub-6 GHz) and WLAN applications.

Design/methodology/approach

To achieve optimum bandwidth, radiation pattern and radiation efficiency, the defected ground structure (DGS) and a rectangular stub connected with the DGS are used. To further cover the sub-6 GHz spectrum (3.4–3.6 GHz) for future 5G communications, a two-element multi-input multi-output (MIMO) antenna configuration is designed by using the single element antenna. The proposed reconfigurable MIMO antenna using a PIN diode is designed on an FR4 substrate with a dielectric constant of 4.4 and a loss tangent of 0.02 and a 35 × 20 × 1.6 mm3 dimension.

Findings

The proposed antenna achieved dual operating bands of 3.4–4.1 GHz (5 G sub-6GHz applications) and 4.99–5.16 GHz (WLAN application) in the D = ON state. For D = OFF state, the proposed antenna achieved 3.55–3.65 GHz and 3.66–4.05 GHz frequency bands for 5G (sub-6GHz) applications. In terms of the envelop correlation coefficient, diversity gain, mean effective gain, total active reflection coefficient and isolation between the ports, the proposed antenna’s diversity performance characteristics are investigated and the obtained values are 0.05, 9.9 dB, ±3dB, −4dB, −15dB, respectively.

Research limitations/implications

The fabricated prototype antenna on FR4 substrate has measurable parameters that are in good agreement with the simulated findings. Due to hardware design limitations, there is a minor difference between software and hardware results.

Originality/value

The proposed MIMO antenna is compact and reconfigurable for 5G (sub-6GHz) and WLAN applications, and from the graph, the measurements and simulations have been found to be in close agreement.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 41 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 2006

Keith Harman and Alex Koohang

The purpose of the study is to explore the extent to which the diffusion of concepts related to information systems and management approximates the rate and the cumulative…

1213

Abstract

Purpose

The purpose of the study is to explore the extent to which the diffusion of concepts related to information systems and management approximates the rate and the cumulative frequency distribution patterns assumed to reflect the diffusion of innovations.

Design/methodology/approach

The diffusion of those concepts was measured via citation analysis of 4,014 publications (journal articles, books, and dissertations) for the period 1973‐2004.

Findings

Two key findings emerged from the study. First, the cumulative frequency distribution approximates the S‐curve of adoption. Second, the rate of adoption is exponential and corroborates an epidemiological model of the rate of adoption recently reported in the literature.

Research limitations/implications

Further research is needed to identify and examine topics or concepts that have run their course and subsequently offer an excellent opportunity to perform ex‐post‐facto studies on the life cycle of innovative concepts or topics. From these studies will be baseline data and easily identifiable “actors” in the diffusion process (authors, editors, reviewers, and dissertation committees) that will provide the impetus for continued, progressively complex research models.

Practical implications

The practical implications of a deeper understanding of the diffusion of innovations are immense. It will enhance understanding of how to better promote research and development and technology transfer. It will enhance understanding of how better to market the fruits of those endeavors.

Originality/value

This paper's findings bring to the scholarly community in the digital era the importance of understanding how new concepts and theories are brought to light and evaluated.

Details

Industrial Management & Data Systems, vol. 106 no. 5
Type: Research Article
ISSN: 0263-5577

Keywords

Article
Publication date: 6 February 2020

Suresh Akkole and Vasudevan N.

Application of electromagnetic band gap (EBG) i.e. electromagnetic band gap technique and its use in the design of microstrip antenna and MIC i.e. microwave integrated…

Abstract

Purpose

Application of electromagnetic band gap (EBG) i.e. electromagnetic band gap technique and its use in the design of microstrip antenna and MIC i.e. microwave integrated circuits is becoming more attractive. This paper aims to propose a new type of EBG fractal square patch microstrip multi band fractal antenna structures that are designed and developed. Their performance parameters with and without EBG structures are investigated and minutely compared with respect to the resonance frequency, return loss, a gain of the antenna and voltage standing wave ratio.

Design/methodology/approach

The fractal antenna geometries are designed from the fundamental square patch and then EBG structures are introduced. The antenna geometry is optimized using IE3D simulation tool and fabricated on low cost glass epoxy FR4, with 1.6 mm height and dielectric materials constant of 4.4. The prototype is examined by means of the vector network analyzer and antenna patterns are tested on the anechoic chamber.

Findings

Combining the square fractal patch antenna with an application of EBG techniques, the gain of microstrip antenna has been risen up and attained good return loss as compared to the antennas without EBG structures. The designs exhibit multi-frequency band characteristics extending in between 1.70 and 7.40 GHz. Also, a decrease in antenna size of 34.84 and 59.02 per cent for the first and second iteration, respectively, is achieved for the antenna second and third without EBG. The experimental results agree with that of simulated values. The presented microstrip antenna finds uses in industrial, scientific and medical (ISM) band, Wi-Fi and C band. This antenna can also be used for satellite and radio detection and range devices for communication purposes.

Originality/value

A new type of EBG fractal square patch microstrip antenna structures are designed, developed and compared with and without EBG. Because of the application of EBG techniques, the gain of microstrip antenna has been risen up and attained good return loss as compared to the antennas without EBG structures. The designs exhibit multi-frequency band characteristics extending in between 1.70 and 7.40 GHz, which are useful for Wi-Fi, ISM and C band wireless communication.

Details

International Journal of Pervasive Computing and Communications, vol. 17 no. 2
Type: Research Article
ISSN: 1742-7371

Keywords

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