Sensing Magnetic Fields With Surface Acoustic Wave (SAW) Sensors

Fayyaz Muhammad,Hu Hong 한국자기학회 2019 Journal of Magnetics Vol.24 No.3

Magnetic sensors are essential sensing elements in various industrial applications, but the design and technology used in the development of these sensors vary from application to application. Recently Surface Acoustic Wave (SAW) sensors have gained considerable attention due to their advantages over conventional sensors. SAW sensors are a class of Microelectromechanical (MEMS) system that use SAW technology and can be easily configured to sense physical parameters including magnetic fields. This paper presents an overview of recent research in the domain of magnetic field sensing based on such SAW devices. The paper describes the most common design approaches in practice and also discusses the key properties of fabrication materials for optimum design and performance. A short review of the processes involved in the development of SAW magnetic sensors is also covered in this paper.

AN IMPLICIT NUMERICAL SCHEME FOR SOLUTION OF INCOMPRESSIBLE NAVIER-STOKES EQUATIONS ON CURVILINEAR GRIDS

Fayyaz, Hassan,Shah, Abdullah Korean Mathematical Society 2018 대한수학회보 Vol.55 No.3

This article deals with implementation of a high-order finite difference scheme for numerical solution of the incompressible Navier-Stokes equations on curvilinear grids. The numerical scheme is based on pseudo-compressibility approach. A fifth-order upwind compact scheme is used to approximate the inviscid fluxes while the discretization of metric and viscous terms is accomplished using sixth-order central compact scheme. An implicit Euler method is used for discretization of the pseudo-time derivative to obtain the steady-state solution. The resulting block tridiagonal matrix system is solved by approximate factorization based alternating direction implicit scheme (AF-ADI) which consists of an alternate sweep in each direction for every pseudo-time step. The convergence and efficiency of the method are evaluated by solving some 2D benchmark problems. Finally, computed results are compared with numerical results in the literature and a good agreement is observed.

Accurate Camera Self-Calibration based on Image Quality Assessment

Fayyaz, Rabia,Rhee, Eun Joo Korea Data Strategy Society 2018 Journal of information technology applications & m Vol.25 No.2

This paper presents a method for accurate camera self-calibration based on SIFT Feature Detection and image quality assessment. We performed image quality assessment to select high quality images for the camera self-calibration process. We defined high quality images as those that contain little or no blur, and have maximum contrast among images captured within a short period. The image quality assessment includes blur detection and contrast assessment. Blur detection is based on the statistical analysis of energy and standard deviation of high frequency components of the images using Discrete Cosine Transform. Contrast assessment is based on contrast measurement and selection of the high contrast images among some images captured in a short period. Experimental results show little or no distortion in the perspective view of the images. Thus, the suggested method achieves camera self-calibration accuracy of approximately 93%.

Emergency Signal Detection based on Arm Gesture by Motion Vector Tracking in Face Area

Fayyaz, Rabia,Park, Dae Jun,Rhee, Eun Joo Korea Information Electronic Communication Technol 2019 한국정보전자통신기술학회논문지 Vol.12 No.1

This paper presents a method for detection of an emergency signal expressed by arm gestures based on motion segmentation and face area detection in the surveillance system. The important indicators of emergency can be arm gestures and voice. We define an emergency signal as the 'Help Me' arm gestures in a rectangle around the face. The 'Help Me' arm gestures are detected by tracking changes in the direction of the horizontal motion vectors of left and right arms. The experimental results show that the proposed method successfully detects 'Help Me' emergency signal for a single person and distinguishes it from other similar arm gestures such as hand waving for 'Bye' and stretching. The proposed method can be used effectively in situations where people can't speak, and there is a language or voice disability.

Stability of the Crystal Structure of -BiFeO3

Fayyaz Ahmad,Ishrat Naz,장재경,이유열 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.4

Density-functional-theory-based calculations have been carried out to investigate the structural stability of bismuth ferrite (-BiFeO3). -BiFeO3 was generally observed to be in a hexagonal phase with the space group R3c. In a new experiment, however, several different crystal structures were suggested, and the triclinic phase (space group: P1) was claimed to be the most stable one. In order to confirm the claim theoretically, we carried out electronic-structure calculations for the various crystal structures suggested experimentally. Unlike the new experimental claim, we found that the hexagonal phase (R3c) had the lowest total energy. Furthermore, the hexagonal phase has a direct band gap of 0.87 eV. Even though this value is much smaller than the experimental value (1.3 eV) because of the notorious deficiency of the generalized-gradient approximation employed in this investigation, it is the closest one to the experimental one among the calculated band gaps of the investigated models. To understand the differences among different models, we investigated the band structure, density of states, and charge density. Along with the bonding process, the charge transfer was analyzed using the atoms-in-molecules theory. Based on this topological analysis of the bonding character, the evolution of the bonding strength with the critical points along the bonding trajectory and the valence charge in the atomic basins are presented quantitatively. The results show that the hexagonal phase has the strongest ionic character. Furthermore, the stability of our claimed model can be further assured by the bond ellipticity, which is a measure of the deviation of the charge distribution of a bond path from axial symmetry.

Induced Magnetic Properties of BN Nanotubes by the Adsorption of First-row Adatoms

Fayyaz Hussain,Muhammad Imran,Nimra Fatima,Anwar Manzoor Rana,R. M. Arif Khalil,Arshad Javid,Muhammad Ismail 한국자기학회 2018 Journal of Magnetics Vol.23 No.1

This work is performed to study the effect of adsorption of various first row adatoms (such as Be, C, F, Li and O) on (8, 0) zigzag boron nitride nanotubes (BNNTs) on their structural, electronic and magnetic properties. These calculations are based on density functional theory using pseudopotentials technique. For this purpose, five different sites namely axial, hexagonal, zigzag, on top of N and/or B (which are the most preferred available sites for adatoms on (8, 0) BNNTs) were utilized. The energetically stable sites for each of the first-row adatoms are found to be different because of their different electronic configurations caused by the charge transfer/ rearrangements between s-p or p-p orbitals. The binding energies of all adatoms on (8, 0) BNNTs have been calculated through structural optimization process after adsorbing these five adatoms at the above said sites on the BNNTs and are found to be in the energy range from -2.04 to 2.96 eV. It is further elaborated that F, Be and C adatoms on (8, 0) BNNTs show strong induced magnetization at specific localized sites depending upon the nature of adatom, whereas weak magnetization is noticed for Li and O adatoms on the BNNTs. Such localized induced magnetization could be associated with the hybridization of s-p or p-p orbitals of adatoms and B and/or N atoms.

Accurate Camera Self-Calibration based on Image Quality Assessment

Rabia Fayyaz,이은주 한국데이터전략학회 2018 Journal of information technology applications & m Vol.25 No.2

This paper presents a method for accurate camera self-calibration based on SIFT Feature Detection and image quality assessment. We performed image quality assessment to select high quality images for the camera self-calibration process. We defined high quality images as those that contain little or no blur, and have maximum contrast among images captured within a short period. The image quality assessment includes blur detection and contrast assessment. Blur detection is based on the statistical analysis of energy and standard deviation of high frequency components of the images using Discrete Cosine Transform. Contrast assessment is based on contrast measurement and selection of the high contrast images among some images captured in a short period. Experimental results show little or no distortion in the perspective view of the images. Thus, the suggested method achieves camera self-calibration accuracy of approximately 93%.

손의 추적과 제스쳐 인식에 의한 슬라이드 제어

( Rabia Fayyaz ),이은주 ( Eun Joo Rhee ) 한국정보처리학회 2012 한국정보처리학회 학술대회논문집 Vol.19 No.1

The work is to the control the desktop Computers based on hand gesture recognition. This paper is worked on real time tracking and recognizes the hand gesture for controlling the slides based on hand direction such as right and left using a real time camera.

Emergency Signal Detection based on Arm Gesture by Motion Vector Tracking in Face Area

Rabia Fayyaz,박대준,이은주 한국정보전자통신기술학회 2019 한국정보전자통신기술학회논문지 Vol.12 No.1

This paper presents a method for detection of an emergency signal expressed by arm gestures based on motion segmentation and face area detection in the surveillance system. The important indicators of emergency can be arm gestures and voice. We define an emergency signal as the ‘Help Me’ arm gestures in a rectangle around the face. The ‘Help Me’ arm gestures are detected by tracking changes in the direction of the horizontal motion vectors of left and right arms. The experimental results show that the proposed method successfully detects ‘Help Me’ emergency signal for a single person and distinguishes it from other similar arm gestures such as hand waving for ‘Bye’ and stretching. The proposed method can be used effectively in situations where people can’t speak, and there is a language or voice disability.

An implicit numerical scheme for solution of incompressible Navier-Stokes equations on curvilinear grids

Hassan Fayyaz,Abdullah Shah 대한수학회 2018 대한수학회보 Vol.55 No.3

This article deals with implementation of a high-order finite difference scheme for numerical solution of the incompressible Navier-Stokes equations on curvilinear grids. The numerical scheme is based on pseudo-compressibility approach. A fifth-order upwind compact scheme is used to approximate the inviscid fluxes while the discretization of metric and viscous terms is accomplished using sixth-order central compact scheme. An implicit Euler method is used for discretization of the pseudo-time derivative to obtain the steady-state solution. The resulting block tridiagonal matrix system is solved by approximate factorization based alternating direction implicit scheme (AF-ADI) which consists of an alternate sweep in each direction for every pseudo-time step. The convergence and efficiency of the method are evaluated by solving some 2D benchmark problems. Finally, computed results are compared with numerical results in the literature and a good agreement is observed.