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Article
Publication date: 8 June 2010

Ting‐Yi Chang, Yu‐Ju Yang and Chun‐Cheng Peng

In keystroke‐based authentication systems, an input device to enter a password is needed. Users are verified by checking the validity of the password and typing characteristics…

1826

Abstract

Purpose

In keystroke‐based authentication systems, an input device to enter a password is needed. Users are verified by checking the validity of the password and typing characteristics. However, some devices have no standard desktop keyboard such as personal digital assistants and mobile phones. With these types of electronics, the system cannot successfully work in the authentication phase while the registration process is implemented based on a computer keyboard. This results in a reduction of system portability. The purpose of this paper is to employ the rhythm clicked by a mouse as another identifiable factor to authenticate a user's identity.

Design/methodology/approach

Mouse click can be replaced by a stylus and fingers on touch screens or numeral buttons on mobile phones. A total of 25 users participated and the click data are based on time instances of pressing and releasing the mouse button, which are captured while the user clicks a rhythm. Three features are calculated using these click data, and a reasonable amount of results with neural networks and other classifiers shows the click characteristics are able to function as another identifiable factor.

Findings

A reasonable amount of results with neural networks and other classifiers shows the click characteristics are able to function as another identifiable factor.

Originality/value

The paper presents a personalized rhythm click‐based authentication system.

Details

Information Management & Computer Security, vol. 18 no. 2
Type: Research Article
ISSN: 0968-5227

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Article
Publication date: 16 September 2013

S.A. Shehzad, M. Qasim, T. Hayat, M. Sajid and S. Obaidat

– The purpose of this paper is to investigate the two-dimensional flow of Maxwell fluid with power law heat flux and heat source over a stretched surface.

160

Abstract

Purpose

The purpose of this paper is to investigate the two-dimensional flow of Maxwell fluid with power law heat flux and heat source over a stretched surface.

Design/methodology/approach

The governing partial differential equations are reduced into ordinary differential equations by applying similarity transformations. Series solutions of velocity and temperature are found by adopting homotopy analysis method (HAM).

Findings

It is found that the velocity decreases by increasing Deborah number and suction parameter. It is also observed that the heat generation parameter leads to a decrease in temperature. Furthermore, the numerical values of local Nusselt number decreased with an increase in Deborah number.

Practical implications

A useful source of information for the investigators on the field of non-Newtonian fluids with heat transfer.

Originality/value

This paper discusses the boundary layer flow of Maxwell fluid with power law heat flux in the presence of heat source.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 7
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 August 2013

M. Mustafaa, T. Hayat and S. Obaidat

This paper aims to discuss the flow and heat transfer characteristics over an exponentially stretching sheet in a nanofluid with convective boundary conditions. The effects of…

406

Abstract

Purpose

This paper aims to discuss the flow and heat transfer characteristics over an exponentially stretching sheet in a nanofluid with convective boundary conditions. The effects of Brownian motion and thermophoresis are also accounted.

Design/methodology/approach

The flow is therefore governed by the Brownian motion parameter (Nb), the thermophoresis parameter (Nt), the Prandtl number (Pr), the Lewis number (Le) and the Biot number (Bi). The analytic solutions of the arising differential systems have been obtained by homotopy analysis method (HAM).

Findings

The temperature rises and the thermal boundary layer thickens with an increase in the Brownian motion and thermophoresis parameters. The surface heat and mass transfer appreciably increase with an increase in the Prandtl and Lewis numbers.

Originality/value

The presented results also include the analysis for constant wall temperature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 16 September 2013

T. Hayat, M. Hussain, M. Awais and S. Obaidat

The boundary layer flow and heat transfer of second grade fluid in a region of the stagnation point over a stretching surface has been examined. Thermal-diffusion (Dufour) and…

146

Abstract

Purpose

The boundary layer flow and heat transfer of second grade fluid in a region of the stagnation point over a stretching surface has been examined. Thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects combined with melting heat transfer are also considered. Suitable transformations are employed to convert the partial differential equations representing the conservation of mass, momentum, energy and diffusion into the system of ordinary differential equations. The series solutions for the flow quantities of interest are presented. Interpretation to velocity, temperature and concentration is assigned. Numerical values of the local Nusselt and Sherwood numbers have been computed. The paper aims to discuss these issues.

Design/methodology/approach

Analytic approach homotopy analysis method (HAM) is used to find the convergent solution of melting heat transfer in a boundary layer flow of a second grade fluid under Soret and Dufour effects.

Findings

In this article the main findings are as second grade fluid; melting heat transfer; Soret and Dufour effects; mass transfer; stretching sheet. It is noted that melting heat transfer enhances the flow. Moreover, the effects of Soret and Dufour parameters have opposite effects on the temperature and concentration fields.

Originality/value

The performed computations show that the behaviors of Prandtl number Pr and Schmidt number Sc on the dimensionless temperature and concentration fields are similar in a qualitative sense.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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Book part
Publication date: 4 December 2020

Abstract

Details

Data Science and Analytics
Type: Book
ISBN: 978-1-80043-877-4

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Book part
Publication date: 5 October 2018

Denise M. Case, Ty Blackburn and Chrysostomos Stylios

This chapter discusses the application of fuzzy cognitive map (FCM) modelling to construction management (CM) challenges and problems. It focuses on the critical issue of managing…

Abstract

This chapter discusses the application of fuzzy cognitive map (FCM) modelling to construction management (CM) challenges and problems. It focuses on the critical issue of managing the complexity and uncertainty inherent in CM by providing a new intelligent layer that enhances classical approaches to construction modelling and management. It investigates how the myriad types of internal and external factors affecting the feasibility and performance of construction projects can be modelled using a fuzzy hybrid method that explores the complex relationships among many contributing factors and assesses and evaluates their impacts on past and future projects. This chapter proposes a hybrid modelling approach in the traditional context of cost, schedule and risk management and describes how augmenting and enhancing existing state-of-the-art tools and processes in CM can assist construction managers. This chapter provides a background on the theory of FCMs, presents foundational and current research, and explains how to apply this approach in the CM domain. This chapter also provides a detailed description of how to develop, modify and employ interactive models to specific CM challenges and problems. It includes a customisable, interactive base model and demonstrates how the model has been applied to specific CM events and issues. Examples are presented that highlight the interplay between project-specific goals and characteristics and the way these impact the interrelated and often opposing triad of cost, schedule and risk. The presented examples and practical applications make this state-of-the-art approach useful to both academic and industry practitioners.

Details

Fuzzy Hybrid Computing in Construction Engineering and Management
Type: Book
ISBN: 978-1-78743-868-2

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Article
Publication date: 14 August 2024

Ala Taleb Obaidat, Yasmeen Taleb Obaidat and Ahmed Ashteyat

In this experimental investigation, the behavior of strengthened/repaired heat-damaged one-way self-compacted concrete (SCC) slabs with opening utilizing…

24

Abstract

Purpose

In this experimental investigation, the behavior of strengthened/repaired heat-damaged one-way self-compacted concrete (SCC) slabs with opening utilizing near-surface-mounted-carbon fiber reinforced polymers (NSM-CFRP) strips was explored.

Design/methodology/approach

CFRP strip configurations, number of strips and inclination were all investigated in this study. For three hours, slabs were exposed to temperatures of 23°C and 500°C. Four-point load was applied to control slabs, enhanced slabs and repaired slabs.

Findings

The results indicate that exposing the slabs to high temperatures reduces their load capability. The number of strips and angle of inclination around the slab opening have a considerable impact on the performance of the strengthened and/or repaired slabs, according to the experimental results. The load capacity, toughness and ductility index of a strengthened and/or repaired slab with opening increase as the number of CFRP strips increases by 143.8–150.5%, 137.3–149.9% and 122.3–124.5%, respectively. The use of NSM strips around the opening with zero inclination showed higher load compared to the NSM strips around the opening with other angles.

Originality/value

It is frequently important to construct openings in the slabs for ventilation, electrical supply, and other purposes. Making openings in slabs might affect the structure’s performance since the concrete and reinforcing would be cut off. SCC is a new type of concrete mixture that can fill in all the voids in the formwork with its own weight without the help of external vibration.  As a result, it is necessary to reinforce the slab under flexure and increase the flexural strength of the SCC slab. Therefore, this work investigates the effect of using NSM-CFRP strip  on the behavior of one way SCC slabs that have been heat-damaged.

Details

International Journal of Structural Integrity, vol. 15 no. 5
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 25 February 2014

T. Hayat, Z. Iqbal, M. Mustafa and A. Alsaedi

This investigation has been carried out for thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects on the boundary layer flow of Jeffrey fluid in the region of…

154

Abstract

Purpose

This investigation has been carried out for thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects on the boundary layer flow of Jeffrey fluid in the region of stagnation-point towards a stretching sheet. Heat transfer occurring during the melting process due to a stretching sheet is considered. The paper aims to discuss these issues.

Design/methodology/approach

The authors convert governing partial differential equations into ordinary differential equations by using suitable transformations. Analytic solutions of velocity and temperature are found by using homotopy analysis method (HAM). Further graphs are displayed to study the salient features of embedding parameters. Expressions of skin friction coefficient, local Nusselt number and local Sherwood number have also been derived and examined.

Findings

It is found that velocity and the boundary layer thickness are increasing functions of viscoelastic parameter (Deborah number). An increase in the melting process enhances the fluid velocity. An opposite effect of melting heat process is noticed on velocity and skin friction.

Practical implications

The boundary layer flow in non-Newtonian fluids is very important in many applications including polymer and food processing, transpiration cooling, drag reduction, thermal oil recovery and ice and magma flows. Further, the thermal diffusion effect is employed for isotope separation and in mixtures between gases with very light and medium molecular weight.

Originality/value

Very scarce literature is available on thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects on the boundary layer flow of Jeffrey fluid in the region of stagnation-point towards a stretching sheet with melting heat transfer. Series solution is developed using HAM. Further, the authors compare the present results with the existing in literature and found excellent agreement.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 31 October 2022

Yasmeen Taleb Obaidat, Wasim Barham and Rawan Abu libdeh

The main aim of this study is to examine the behavior of reinforced concrete short columns strengthened using longitudinal near surface mounted (NSM)-carbon fiber reinforced…

78

Abstract

Purpose

The main aim of this study is to examine the behavior of reinforced concrete short columns strengthened using longitudinal near surface mounted (NSM)-carbon fiber reinforced polymer (CFRP) strips.

Design/methodology/approach

A full 3D-finite element (FE) model was developed using ABAQUS in order to conduct the analysis. The model is first validated based on experimental data available in the literature, and then the effect of concrete compressive strength, number of CFRP strips that are used and the spacing between them were taken in consideration for both concentric and eccentric loading cases. The parametric study specimens were divided into three groups. The first group consisted of unstrengthened columns and served as control specimens. The second group consisted of columns strengthened by longitudinal CFRP strips at two opposite column faces.

Findings

The results of this study are used to develop interaction diagrams for CFRP-strengthened short columns and to develop best-fit equations to estimate the nominal axial load and moment capacities for these strengthened columns. The results showed that the specimens that were strengthened using more longitudinal CFRP strips showed a significant increase in axial load capacity and a significant improvement in the interaction diagram, especially at large load eccentricity values. This result can be justified by the fact that longitudinal strips effectively resist the bending moment that is generated due to eccentric loading. Generally, the process of strengthening using longitudinal strips only has a reasonable effect and it can be typically considered an excellent choice considering the economic aspect when the budget of strengthening is limited.

Originality/value

This research aims at studying the performance of strengthened rectangular reinforced concrete short columns with CFRP strips using FE method, developing interaction diagrams of strengthened columns in order to investigate the effect of different parameters such as compressive strength (20, 30 and 40 MPa), number of CFRP strips (1, 2, 3 and 4) and the spacing between CFRP strips in terms of the ratio of CFRP center point distance to column outside dimension ratio (0.60, 0.70 and 0.80) on the behavior of strengthened RC columns and improving empirical formulas to predict the nominal axial load and moment capacities of strengthened RC columns. These parameters that directly affect short column load carrying capacity are presented in ACI-318 (2014).

Details

International Journal of Building Pathology and Adaptation, vol. 42 no. 6
Type: Research Article
ISSN: 2398-4708

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Article
Publication date: 25 February 2014

T. Hayat, R. Naz, S. Asghar and A. Alsaedi

The purpose of this paper is to study the heat and mass transfer with Soret-Dufour effects for the magnetohydrodynamic three-dimensional flow of second grade fluid in the rotating…

163

Abstract

Purpose

The purpose of this paper is to study the heat and mass transfer with Soret-Dufour effects for the magnetohydrodynamic three-dimensional flow of second grade fluid in the rotating frame of reference.

Design/methodology/approach

Series solution is obtained by homotopy analysis method.

Findings

Increase in Soret number, Schmidt number and Dufour number, the heat transfer increases and mass transfer decreases. Effects of Prandtl and Eckert numbers are qualitatively similar as they assist the temperature profile and reduce the concentration of species. Increase in the length of the channel versus height increases the temperature profile but decreases the concentration field. Increase in the second grade fluid parameter causes reduction in both the temperature and concentration fields. The heat flux values at the lower plate are smaller than the values at the upper plate, whereas the situation is opposite in the case of mass transfer.

Originality/value

These findings will be useful for the fluid flow in porous channel.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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