A. B. M. Aowlad Hossain

Magnetic nanoparticle density mapping from the magnetically induced displacement data: a simulation study

BackgroundMagnetic nanoparticles are gaining great roles in biomedical applications as targeted drug delivery agents or targeted imaging contrast agents. In the magnetic nanoparticle applications, quantification of the nanoparticle density deposited in a specified region is of great importance for evaluating the delivery of the drugs or the contrast agents to the targeted tissues. We introduce a method for estimating the nanoparticle density from the displacement of tissues caused by the external magnetic field.MethodsWe can exert magnetic force to the magnetic nanoparticles residing in a living subject by applying magnetic gradient field to them. The nanoparticles under the external magnetic field then exert force to the nearby tissues causing displacement of the tissues. The displacement field induced by the nanoparticles under the external magnetic field is governed by the Naviers equation. We use an approximation method to get the inverse solution of the Naviers equation which represents the magnetic nanoparticle density map when the magnetic nanoparticles are mechanically coupled with the surrounding tissues. To produce the external magnetic field inside a living subject, we propose a coil configuration, the Helmholtz and Maxwell coil pair, that is capable of generating uniform magnetic gradient field. We have estimated the coil currents that can induce measurable displacement in soft tissues through finite element method (FEM) analysis.ResultsFrom the displacement data obtained from FEM analysis of a soft-tissue-mimicking phantom, we have calculated nanoparticle density maps. We obtained the magnetic nanoparticle density maps by approximating the Naviers equation to the Laplacian of the displacement field. The calculated density maps match well to the original density maps, but with some halo artifacts around the high density area. To induce measurable displacement in the living tissues with the proposed coil configuration, we need to apply the coil currents as big as 104A.ConclusionsWe can obtain magnetic nanoparticle maps from the magnetically induced displacement data by approximating the Naviers equation under the assumption of uniform-gradient of the external magnetic field. However, developing a coil driving system with the capacity of up to 104A should be a great technical challenge.

ECG based biometric human identification using chaotic encryption

Biometric identification provides a reliable performance on recognition of identity for different security and authentication management problems. With the development of technology, the privacy and security is the main concern as technology can be falsified. In recent decades biometric traits are the trusted choice to the researchers and there are strong documentations on biometric traits like human electrocardiogram which is the time changing electrical impulse signal passing through heart is able to use for identity subject identification. In this work, an analytic and serviceable analysis of the ECG for human identification is presented. A new approach based on chaotic encryption (CE) of continuous wavelet transformed (CWT) ECG signal has been proposed. The CWT used here to obtain similarity pattern of each individual and CE of the CWT decomposed signal used for subject identification. The proposed approach has been tested using 11 different subjects ECG signal available at MIT-BIH arrhythmia database. The obtained results show that the identification rate is 96.82%. The findings of this study can be helpful to develop effective biometric human identification system.

Design and implementation of block cipher in hummingbird algorithm over FPGA

The Hummingbird algorithm is applied in secure systems like RFID tags, wireless sensor nodes and smart integrated circuits. Hummingbird is a lightweight algorithm which consists of block cipher of 256-bit key and encrypts a 16bit data in one operation. In this paper, a block cipher for hummingbird algorithm is designed and implemented over Spartan-2 FPGA. The encryption and decryption unit are designed separately and finally, it is observed that the decrypted result perfectly matches with main data. The proposed architecture is planned to keep compact so that rest of reconfigurable areas of FPGA can be efficiently used for other purposes. As compactness is necessary for systems embedded with cryptography part, we expect that the proposed design can show technical usefulness.

Lightning Surge Analysis on Vertical Tower using Electromagnetic Transient Program (EMTP)

This paper demonstrates the electromagnetic behaviour of transient response of lightning surge strike on vertical tower for wireless communications and power systems. Vertical tower surge responses are analysed using electromagnetic transient program (EMTP). The accuracy of this method is shown to be satisfactory with the simulation result based on the numerical electromagnetic code (NEC-2) that were carried out on vertical tower as reduced scale model. Lightning over-voltages must be taken into account when designing a tower. In the world, especially in Japan various studies, therefore, have been done to measure the characteristics of the line components and to develop their equivalent circuit models for the electromagnetic transient program (EMTP) simulations. Surge impedance is calculated by both the vertical and horizontal stroke analyses and then the single vertical and multi-storey tower surge characteristics are investigated in this work.

Implementation of 2D torus automorphisms for image encryption on FPGA

The convenience of torus automorphism is widely used in network security, data encryption, image watermarking and pattern recognition. This paper presents an implementation and synthesis of FPGA based multimedia image encryption technique by 2D torus automorphism. The proposed computational algorithm of 2D torus automorphism is simple as only three addition and two multiplication logic operations is used for generating the positions of next incident matrices. Therefore this simple system of equation of torus automorphism can be implemented on field programmable gate array (FPGA). The designs were realized in Verilog HDL and synthesized on Vertex-5 FPGA. The encrypted implementations were completely parameterized with respect to the input image dimension and the recurrence number which is dependent on the value of torus coefficient. All exhaustive obtained results regarding the logic block uses, memory requirements and timing report associated with the proposed architecture are investigated. The results consummate the veracity of 2D torus automorphism. This applied work can be useful for real time image encryption applications.

A simulation study on viscosity change effects in ultrasound based carotid atherosclerosis diagnosis

Common cardiovascular diseases like heart attack and stroke are the major cause of mortality and disability in recent decades. Increased blood viscosity is an independent risk factor for atherosclerotic cardiovascular diseases. Elevated blood viscosity is associated with atherosclerosis and its growth. The knowledge of the arterial hemodynamics resulted due to atherosclerosis with different level of blood viscosity can clarify the relationship between artery stenosis and symptoms, and, finally, the risk of heart attack and stroke. Hence proficient imaging of blood flow has great clinical importance to understand the origin and evolution of disease. Therefore, investigation and detection of viscosity change and its effect might be helpful for better diagnosis of carotid atherosclerosis. In this simulation work, hemo-disturbances are studied in a carotid artery finite element model (FEM) with atherosclerosis under different viscosities consideration using computational fluid dynamics (CFD). The obtained FEM data are used to reconstruct color flow image of blood velocities using ultrasound radio-frequency (RF) signals to study atherosclerosis detecting the viscosity changes. The findings of this study suggest that ultrasound based blood flow image can detect the viscosity change effect related to atherosclerosis growth. We think the findings will be helpful to develop effective ultrasound imaging technique for atherosclerosis diagnosis.

A low cost stethoscopic system for real time auscultation of heart sound

Auscultation of heart sounds has great importance as they are related to the anatomy and physiology of cardiovascular systems as well as to diagnosis of cardiovascular disease. In this paper, a microcontroller based stethoscopic system for auscultation of heart has been presented with a strategic emphasis on low-cost and real time capability. The system consists of acoustic sensor, filter, signal processing system, speaker and display devices etc. The heart sound signal has been acquisited and passed through 20-250 Hz band-pass filter before processed by ATmega8A microcontroller. Output has been shown in real-time through LED blinking as well as processed to display the cardiac waveform and beat rate. Performance of this device is good in terms of accuracy. Within around 11

Simulation analysis on effectiveness of nonlinear ultrasound imaging using synthetic cyst phantoms

this device can be implemented, which is cheaper compared to other digital stethoscopes available on market.

A simulation study on strain image calculation from digital breast tomosynthesis data

Application of nonlinear ultrasound techniques is recently gaining importance in medical imaging. Ultrasound imaging is a commonly used diagnostic method due to its low cost, safe and portable facilities. However, linear ultrasound imaging provides poor resolutions. The harmonic content can provide better resolution rather than the fundamental frequency. Conversely, increasing complexity is obvious impact of nonlinearity consideration. This simulation study presents a comparative analysis of linear and non-linear ultrasound imaging of different synthetic phantoms in order to find the effectiveness on nonlinear ultrasound techniques. We have used two widely accepted ultrasound simulator Field II and CREANUIS. Synthetic phantom has been developed considering both linear and non-linear propagation media with possible inhomogeneous coefficient of nonlinearity. Simulated images have been examined in terms of SNR, CNR and resolution. The nonlinear imaging has showed its effectiveness over linear technique for the images with closely located multiple cysts where lateral resolution is important.

Hand motion capture system in piano playing

When breast is subjected to compression, its tissues are deformed according to the elasticity distribution inside the breast and the pressure distribution on the breast surface. If multiple 3D digital breast tomosynthesis (DBT) are taken with different compressing force, the deformation information of the compressed breast can be estimated. Tumor tissues, which are known to be much stiffer than normal breast tissues, would have smaller deformation as compared to the normal background tissues. Hence, the x-ray image intensity as well as displacements at the tumor region would change less than the background tissues. In this simulation study, we try to find out 3D strain map using displacement data taken from 3D breast tomosynthesis with different compression levels. We use finite element model (FEM) of breast with compressing device and calculated breast deformation data of compressed breast to estimate the strain. The study will be helpful to enhance tumor/cancerous region detection capability of DBT.