Browsing by Author "Rahman, S.M.M."

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Energy intake and expenditure of obese and non-obese urban Bangladeshi children
(2002) Rahman, S.M.M.; Kabir, I.; Akter, B.M.D.; Begum, H.A.; Khaled, M.A.; Rashid, H.A.; Bhuyan, M.A.H.; Malek, M.A.; Khan, M.R.
Generating near-field fresnel diffraction patterns by iterative fresnel integrals method: a computer simulation approach
(© 2012 Nova Science Publishers, Inc., 2012-12) Abedin, Kazi Monowar; Rahman, S.M.M.; Haider, A F M Yusuf
Recently the concept of computer-based virtual experiments in all branches of physics has generated wide spread interests among the researchers. In this Chapter, we describe the Iterative Fresnel Integrals Method (IFIM), which is essentially a computer-based simulation method employing repeated calculation of Fresnel integrals to obtain the complete near-field Fresnel diffraction patterns or images from rectangular-shaped apertures in any given experimental configuration. The images observed in the far-field (the Fraunhofer regime) can be considered as a special case in this IFIM method. MATLAB codes are used to perform this Fresnel simulation in any personal computer, with a program execution time of the order of a minute. The IFIM method simulates a real diffraction experiment in a PC, and can also be a useful pedagogic tool to understand the details of the diffraction process. Here, we discuss the theoretical background of the method, as well as the complete implementation of the technique in MATLAB codes. Three specific applications of the iterative Fresnel integral method are considered in this Chapter: (a) single rectangular or square apertures, (b) double apertures and slits with arbitrary separations, and (c) square apertures tilted at an arbitrary angle to the optical axis. In each of these cases, the transition to the far-field (the Fraunhofer regime) is also simulated and discussed. Quantitative comparisons of the far-field intensity distributions with the analytic expressions from the Fraunhofer theory are made whenever possible. Double apertures in two dimensions, and apertures tilted simultaneously around two orthogonal axes are also briefly considered and simulated. Future possible extensions of the method to more complicated problems, such as multiple slits and diffraction gratings are also mentioned therein.
Roboticon: A realistic platform to imitate facial expressions
(Institute of Electrical and Electronics Engineers Inc., 2016-12-20) Kundu, A.K.; Islam, D.; Rahman, S.M.M.
This paper presents a concept that quickly detects the facial expressions of humans with a sufficient accuracy and imitates the expressions remotely in terms of robot-based mimics. In traditional online communication of expressions, it is not certain that the sender remains in the same state of expression, when the state is actually received in the remote side. In addition, the expression received in the remote side is mimicked by special visual characters commonly known as emoticons. The approach presented in this paper addresses the issues of real-time detection, communication, and imitation of expressions in order to solve the existing shortcomings. In particular, a computationally efficient intensity threshold-based algorithm is adopted to detect facial expressions from video signals. Because of such a simplicity, the proposed system ensures fast detection of an expression, which is quite convenient for real-time communication. At the same time, the system copies the expression on the face of a humanoid robot at the receiving end. It is expected that this novel approach, which is referred to as Roboticon will play a key role to imitate facial expressions in real-time.