Muhammad Nomani Kabir

Numerical solutions for gyrotactic bioconvection in nanofluid-saturated porous media with Stefan blowing and multiple slip effects

A mathematical model is developed to examine the effects of the Stefan blowing, second order velocity slip, thermal slip and microorganism species slip on nonlinear bioconvection boundary layer flow of a nanofluid over a horizontal plate embedded in a porous medium with the presence of passively controlled boundary condition. Scaling group transformations are used to find similarity equations of such nanobioconvection flows. The similarity equations are numerically solved with a Chebyshev collocation method. Validation of solutions is conducted with a Nakamura tri-diagonal finite difference algorithm. The effects of nanofluid characteristics and boundary properties such as the slips, Stefan blowing, Brownian motion and Grashof number on the dimensionless fluid velocity, temperature, nanoparticle volume fraction, motile microorganism, skin friction, the rate of heat transfer and the rate of motile microorganism transfer are investigated. This work is relevant to bio-inspired nanofluid-enhanced fuel cells and nano-materials fabrication processes.

Lie group analysis and numerical solution of magnetohydrodynamic free convective slip flow of micropolar fluid over a moving plate with heat transfer

In this paper, we investigate magnetohydrodynamic free convective flow of micropolar fluid over a moving flat plate using the Lie group transformations and numerical methods. Instead of using conventional no-slip boundary conditions, we used both the velocity and thermal slip boundary conditions to achieve physically realistic and practically useful results. The governing boundary layer equations are non-dimensionalized and transformed into a set of coupled ordinary differential equations (ODEs) using similarity transformations generated by the Lie group, before being solved numerically using Matlab stiff ODE solver ode15s and Matlab trust-region-reflective algorithm lsqnonlin. The effects of governing parameters on the dimensionless velocity, angular velocity, temperature, skin friction and heat transfer rate are investigated. Our analysis revealed that the dimensionless velocity and angular velocity decrease whilst the dimensionless temperature increases with the velocity slip parameter. Thermal slip reduces the dimensionless velocity and temperature but raises the dimensionless angular velocity. Magnetic field suppresses the velocity but elevates the temperature and angular velocity. Results reported in this paper are in good agreement with the ones reported by the previous authors.

A Hybrid Digital-Signature and Zero-Watermarking Approach for Authentication and Protection of Sensitive Electronic Documents

This paper addresses the problems and threats associated with verification of integrity, proof of authenticity, tamper detection, and copyright protection for digital-text content. Such issues were largely addressed in the literature for images, audio, and video, with only a few papers addressing the challenge of sensitive plain-text media under known constraints. Specifically, with text as the predominant online communication medium, it becomes crucial that techniques are deployed to protect such information. A number of digital-signature, hashing, and watermarking schemes have been proposed that essentially bind source data or embed invisible data in a cover media to achieve its goal. While many such complex schemes with resource redundancies are sufficient in offline and less-sensitive texts, this paper proposes a hybrid approach based on zero-watermarking and digital-signature-like manipulations for sensitive text documents in order to achieve content originality and integrity verification without physically modifying the cover text in anyway. The proposed algorithm was implemented and shown to be robust against undetected content modifications and is capable of confirming proof of originality whilst detecting and locating deliberate/nondeliberate tampering. Additionally, enhancements in resource utilisation and reduced redundancies were achieved in comparison to traditional encryption-based approaches. Finally, analysis and remarks are made about the current state of the art, and future research issues are discussed under the given constraints.

Bit allocation strategy based on Psychovisual threshold in image compression

Image compression leads to minimize the storage-requirement of an image by reducing the size of the image. This paper presents a bit allocation strategy based on psychovisual threshold in image compression considering a similar idea of audio coding. In the audio coding, a dynamic bit allocation to each signal is related to the concept of variable block coding and bit allocation is performed on either a short block or long block of sample signals. Similarity, in our technique, more bits are assigned to a local block with visually-significant low frequency order, and fewer, with visually-insignificant high frequency order. This paper presents a bit allocation strategy based on psychovisual threshold in image compression. A psychovisual threshold is developed by minimizing the visual impact on the image quality degradation in image frequency coding. This paper investigates the error generated by the discrete cosine transform and sets the maximum acceptable error as a psychovisual threshold. The average reconstruction error per pixel on frequency order is utilized to prescribe a set of bit allocations which provide a significant improvement on the quality of image reconstruction at relatively low bit rates. The experimental results show that our dynamic bit-allocation technique in image compression manages to overcome artifact images in the image output. The proposed bit allocation strategy improves the quality of image reconstruction by about 20% compared to JPEG compression. This bit allocation strategy is designed to replace the traditional role of the quantization process in image compression.

A connection probability model for communications networks under regional failures

Communications networks are often disrupted by human-initiated and natural disasters such as terrorist bombings, aerial bombardment, earthquakes, floods and volcanic eruptions. Estimating the connection probability of a communications network under a regional failure caused by such an event is essential to evaluating network performance. This paper proposes a probabilistic model called the Connection Probability of a Communications Network under Regional Failures. The proposed model estimates the connection probability of each link that connects a pair of nodes under a failure scenario; these probabilities are then used to compute the generalized connection probability metrics for the network of interest. The model is continuous over its failure region, which is considered to be circular with a certain radius. The maximum failure impact occurs at the epicenter and the impact gradually drops to zero beyond the failure circle. The model helps identify the failed network links and their degrees of failure. A case study involving the U.S. backbone communications network with various failure epicenters and radii demonstrates the applicability and utility of the proposed model.

Blockchain Security Hole: Issues and Solutions

Blockchain technology is widely known because it is the underlying technology used by the bitcoin. It became more popular because it also can be used as backbone for various applications in finance, media, security and others. One of the main concerns for this technology is how secure the information that the users distributed over the network. This paper studies and highlights the important security issues concerned and discusses the solutions that proposed by the researchers and theoretical solution proposed to address some of the issues. However, this approach needs to be investigated further if it is to be implemented later in the near future. This paper can give direction for future researchers who are interested of this area.

Analysis of a Transportation System With Correlated Network Intersections: A Case Study for a Central Urban City With High Seasonal Fluctuation Trends

Intelligent transportation systems (ITSs) providing efficient road-transportation strategies have recently become a very active research area. Efficient transportation of visitors to/from highly congested sites is one of the most important challenges addressed by ITS. A transportation-system analysis is presented here and is applied on an urban city ring road network that encompasses a major attraction site characterized by correlated network-intersections and large vehicle-pedestrian movement conflicts. The presented model analysis first examines the influences exerted by network-correlations at intersection-points, and second, presents case-study evacuation scenarios examined under varying circumstances and flow-requirements within each segment of the modeled network. The significance of this paper is clearly evident in emergency/evacuation scenarios or in design considerations in which the influence of correlated network-intersections must be known beforehand. As a main contribution, a mathematical model was developed with simulations evaluating the current system using real-life data as statistical input to our model. Results had demonstrated the counter-propagation effect between adjacent intersections along the ring road of an urban congested city. Furthermore, the study modeled and investigated two emergency-evacuation scenarios within chosen segments at road network sites entering and exiting the central area in order to demonstrate how efficient evacuation can be conducted during an emergency scenario. It is expected that the results of this model can also be extended and applied for evacuation analyses for other sites with similar practical conditions or in other congested cities in which correlated intersections have a significant presence that must be included in the real-life analysis of a transportation system.

Block-based Tchebichef image watermarking scheme using psychovisual threshold

Digital multimedia has drastically increased the production and distribution of digital data in the recent years. Unauthorized manipulation and ownership of digital image have become a serious issue. In this paper, we propose a watermarking scheme which uses block-based Tchebichef moments considering psychovisual threshold. The psychovisual threshold is used to prescribe the potential location of embedded watermark. The proposed watermarking scheme considers minimum modified entropy values to determine the embedded blocks. The lowest psychovisual error threshold on each selected block are chosen as the best location to insert the watermark image. Experimental results demonstrate that the embedding watermark into the lowest Tchebichef psychovisual threshold can produce a good level of imperceptibility. The watermark recovery is strongly robust against JPEG compression.

On mitigating hop-to-hop congestion problem in IoT enabled Intra-Vehicular communication

Internet of Things enabled Intra-Vehicular Network (IVN) refers to the network where large number of sensors are connected with each other for sharing the vehicles status information in order to develop a smart vehicular system. The number of sensor nodes in the vehicle has increased significantly due to the increasing vehicular applications. The phenomenon of congestion poses a problem in the IVN where the traffic load and number of sensors are increased. This problem can be resolved by mitigating the limitation of the existing Media Access Control (MAC) protocols. In this paper, we address this issue and proposed a MAC strategy for solving this problem in this network. Furthermore, we discuss the design of IVN scenario and the performance is evaluated in terms of end-to-end delay. The simulation results reveal the effectiveness of our proposal.

Quran-on-Chip (QoC): An Embedded System Framework and Design for Electronic Quran Dissemination for Internet-Enabled Devices

This paper demonstrates the concept of applied and embedded system design for authentic Quran propagation within a single-chip by embedding the digital Quran content onto an ARM micro controller that provides programming and playing capabilities for the publisher/manufacturer with only playing/reading functionality for end-user devices. Significantly, such functionality can be easily deployed by integrating the Quran-on-Chip (QoC) subsystem within future multimedia product designs or via USB communications for present devices. Quran multimedia content is embedded/programmed using the Embedded-C language, with the advantage that the developed program is also compatible for embedding in other micro controller architectures. Significantly, this paper presents a complete framework for the QoC design approach with the results of implementation being demonstrated. Finally, an outlook into the prospect of embedded-system design for multimedia Quran dissemination shall be explored with comments on challenges and opportunities for future work.