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Dhaka, Bangladesh

Song X.,University of British Columbia | Hassan Md.Z.,The University of Asia Pacific | Cheng J.,University of British Columbia
Electronics Letters | Year: 2012

Bit error rate (BER) performance is studied for a subcarrier differential quadrature phase-shift keying modulated optical wireless communication system over the Gamma-Gamma turbulence channels. A closed-form BER expression is derived using a series expansion approach. Asymptotic analysis shows that the diversity order of the considered system depends only on the smaller channel parameter. © 2012 The Institution of Engineering and Technology. Source

Fatemi M.N.,The University of Asia Pacific | Rahman T.,BDDL Housing LTD.
Urbani Izziv | Year: 2015

This study investigates the projected outcome of the Bangladesh government's decision to relocate the Hazaribagh tanneries outside Dhaka, the capital of Bangladesh. Ever since the early industrialisation of Bangladesh, leather processing industries have played a significant economic role. In Dhaka, these industries are mainly concentrated in Hazaribagh, an important area in the southwestern part of the city. Hazaribagh is a junction connecting the new township with the old one. However, the use of inferior technologies, coupled with the absence of proper industrial waste-management and waste-treatment facilities, have destroyed the ecology of the Hazaribagh area and badly impacted its surroundings. Consequently, moving the tanneries from Hazaribagh and then redeveloping the area offers a unique opportunity in the country's sustainable urban regeneration. Regenerating the Hazaribagh urban brownfield can serve as a model for sustainable twenty-first-century neighbourhoods, incorporating contemporary facilities and environmentally friendly elements for healthy living. This study analyses the Hazaribagh area's potential as an example of a planned sustainable area for the entire city, free from the severe pollution that it is notorious for. Source

Emura K.,Japan National Institute of Information and Communications Technology | Rahman M.S.,The University of Asia Pacific
SECRYPT 2012 - Proceedings of the International Conference on Security and Cryptography | Year: 2012

As an extension of public key encryption with keyword search (PEKS), secure channel free PEKS (SCFPEKS) has been considered. Generic construction of SCF-PEKS (with adaptive security) from strongly existentially unforgeable one-time signature, selective-tag CCA secure tag-based encryption (TBE) and anonymous identity-based encryption (IBE) has been proposed in ISC2011. Since this construction follows the double encryption, where a ciphertext of anonymous IBE is encrypted by TBE, hybrid encryption is applied because usually the ciphertext space of IBE is not equal to the plaintext space of TBE. In this paper, we show that hybrid encryption is not necessary as long as previously-known anonymous IBE schemes are used as a building tool of adaptive SCF-PEKS. Our result leads to a composability of IBE schemes whether they can be applied for constructing adaptive SCF-PEKS or not. Moreover, since we can exclude DEM part, our construction is efficient compared to the original one. Source

Rahman A.,The University of Asia Pacific | Podder J.,Bangladesh University of Engineering and Technology
Indian Journal of Physics | Year: 2012

The pure ammonium dihydrogen phosphate (ADP) and ethylenediamine tetra acetic acid (EDTA) added ADP crystals were grown by isothermal evaporation method. The solubility of ADP was determined for five different temperatures. Metastable zone width of aqueous solutions of ADP saturated at different temperatures was determined by nucleation method in pure form and adding with 0.5 mol.% EDTA. The induction period τ was measured and experiments were performed at selected degrees of supersaturation (C/C*) and the critical nucleation parameters like interfacial energy (σ), energy of formation of the critical nucleus (ΔG*) were calculated based on the classical theory of nucleation. The grown crystals have been subjected to study the structural, optical and mechanical properties. FTIR analysis has been carried out to characterize the grown crystals. The transmission spectra from (100) planes of the grown crystals show that the transmission increases from 55.86 to 83.23% due to addition of EDTA in the visible region and band gap was found to increase from 1.31 to 1.41 eV. The microhardness test was carried out on (100) plane. The load dependent hardness and work hardening coefficient were measured. © 2012 Indian Association for the Cultivation of Science. Source

Roy N.,The University of Asia Pacific | Tasnim S.,Stamford University Bangladesh | Mamun A.A.,Jahangirnagar University
Physics of Plasmas | Year: 2012

A rigorous theoretical investigation has been made on the formation of the nonlinear structures (viz., solitary waves, double layers) in a dusty electron-positron-ion plasma (containing inertialess degenerate electrons and positrons, cold, mobile, inertial ions, and negatively charged stationary dust). The pseudo potential method has been employed in this theoretical investigation. The basic features of the solitary waves and double layers, which are associated with positive ion dynamics and pressures of degenerate electrons and positrons, are identified. The co-existence of positive and negative solitary waves, and existence of either positive or negative double layers have been theoretically observed for certain range of different plasma parameters. The implications of our results in astrophysical compact objects have been briefly discussed. © 2012 American Institute of Physics. Source

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