797 research outputs found
Highly birefringent elliptical core photonic crystal fiber for terahertz application
Get PDFAbstract not availableJakeya Sultana, Md. Saiful Islam, Mohammad Faisal, Mohammad Rakibul Islam, Brian W.-H. Ng, Heike Ebendorff-Heidepriem, Derek Abbot
Near-zero dispersion flattened, low-loss porous-core waveguide design for terahertz signal transmission
Get PDFAbstract not availableJakeya Sultana, Md. Saiful Islam, Javid Atai, Muhammad Rakibul Islam, and Derek Abbot
Design and characterization of a low-loss, dispersion-flattened photonic crystal fiber for terahertz wave propagation
No full textAbstract not availableMd. Saiful Islam, Jakeya Sultana, Javid Atai, Mohammad Rakibul Islam, Derek Abbot
Extremely low material loss and dispersion flattened TOPAS based circular porous fiber for long distance terahertz wave transmission
No full textAbstract not availableMd. Saiful Islam, Jakeya Sultana, Sohel Rana, Mohammad Rakibul Islam, Mohammad Faisal, Shubi F. Kaijage, Derek Abbot
Ultra low-loss hybrid core porous fiber for broadband applications
No full textAbstract not availableMd. Saiful Islam, Jakeya Sultana, Javid Atai, Derek Abbott, Sohel Rana, And Mohammad Rakibul Isla
Mediation Effect of Metal Mixtures in the Association Between Socioeconomic Status and Self-rated Health Among US Adults: A Weighted Quantile Sum Mediation Approach
Get PDFA Novel Approach for Spectroscopic Chemical Identification Using Photonic Crystal Fiber in the Terahertz Regime
No full textA novel highly sensitive porous core-photonic crystal fiber (PC-PCF) has been designed and analyzed for detection of chemical analytes in the terahertz frequency range. The PC-PCF is designed using rectangular structured air holes in the core with a kagome structured cladding. The full vectorial finite-element method is used to tune the geometrical parameters and to characterize the fiber. Our results demonstrate a high relative chemical sensitivity with significantly lower confinement loss for different analytes. Moreover, the PCF shows near zero dispersion variation, high modal effective area, high birefringence, and high numerical aperture. The practical realization of the fiber is feasible with present fabrication techniques. Our optimized PCF has commercial applications in chemical sensing as well as applications in terahertz systems that require guided polarization preserving transmission.Md. Saiful Islam, Jakeya Sultana, Kawsar Ahmed, Mohammad Rakibul Islam, Alex Dinovitser, Brian Wai-Him Ng and Derek Abbot
A modified hexagonal photonic crystal fiber for terahertz applications
No full textAvailable online 12 April 2018We present a Zeonex based highly birefringent and dispersion flattened porous core photonic crystal fiber (PC-PCF) for polarization preserving applications in the terahertz region. In order to facilitate birefringence, an array of elliptical shaped air holes surrounded by porous cladding is introduced. The porous cladding comprises circular air-holes in a modified hexagonal arrangement. The transmission characteristics of the proposed PCF are investigated using a full-vector finite element method with perfectly matched layer (PML) absorbing boundary conditions. Simulation results show a high birefringence of 0.086 and an ultra-flattened dispersion variation of ±0.03 ps/THz/cm at optimal design parameters. Besides, a number of other important wave-guiding properties including frequency dependence of the effective material loss (EML), confinement loss, and effective area are also investigated to assess the fiber's effectiveness as a terahertz waveguide.Md. Saiful Islam, Jakeya Sultana, Mohammad Faisal, Mohammad Rakibul Islam, Alex Dinovitser, Brian W-H. Ng, Derek Abbot
Compression Schemes for High Dimensional Data based on Extendible Multidimensional Arrays
No full textThis thesis is submitted to the Department of Computer Science and Engineering , Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Computer Science and Engineering, March, 2015.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 64-67).Traditional Multidimensional Array (TMA) is an important data structure for handling
large scale multidimensional dataset, but they are not extendible during run time. Another
problem for representing the real life data by multidimensional arrays is that it creates high
degree of sparsity. Due to this sparsity problem and increasing size of the data structures,
it becomes necessity to develop a suitable scheme to compress the multidimensional array
in an efficient way so that it takes comparatively low memory storage. To minimize both
of these sparsity and reorganization problem novel schemes are proposed to compress high
dimensional data based on dynamically extendible array. In this research work we propose
compression schemes based on Extendible multidimensional array. The proposed
compression schemes are Extendible array based Compressed Row Storage (EaCRS)
scheme, Linearized Extendible array based Compressed Row Storage (LEaCRS) scheme
and Extendible array based Chunk Offset Compression Scheme (EaChOfJ. The main idea
of both the EaCRS and LEaCRS scheme is to compress the subarrays independently found
from the existing extendible array. LEaCRS scheme differs from EaCRS scheme only in
the way that the LEaCRS
scheme needs to linearize each subarray first and then
compresses the subarray independently. EaChOJj scheme linearizes each subarray
independently and breaks a large multi dimensional extendible array into chunks for
compressing. In this scheme, a maximum size of each chunk is considered and chunks are
formed by one or more subarrays. We evaluated our proposed schemes by comparing
compression ratio, data retrieval time and extension cost with CR3 on TMA and
ChunkOJjei
Compression on TMA. Both analytical analysis and experimental tests were
conducted. The analytical analysis and experimental results show that the proposed
schemes have better range of usability and compression ratio for practical applications
than traditional schemes. Furthermore, we found that the retrieval time of the proposed
compression schemes are independent of different dimensions. The increment operation
will be efficient in the proposed compression schemes than the existing traditional
compression schemes because it increments without reorganizing the previous data.Md. Rakibul IslamMaster of Science in Computer Science and Engineerin
Herd behavior in the Bangladeshi banking sector
No full textThis study aims to investigate the existence and nature of herding behavior in the banking sector in Bangladesh. It uses daily closing prices of 30 listed commercial banks from January 2007 to December 2018 to detect herding. This study confirms the presence of herding in the banking industry for the whole study period. Further, it finds herding in the banking sector during the domestic financial crisis and no herding in the Global financial crisis. By separating the study period into a rising market and a falling market condition, this paper finds asymmetry in herding behavior in the banking sector. This phenomenon is further confirmed when the extreme market condition of the bull and bear phase is used. Investors in the banking industry flock together ignoring any private information to reap the market return at the bull period while they avoid the crowd during the bear phase
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