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Mathematical Modelling for Heat Transfer of a Micropolar Fluid along a Permeable Stretching/Shrinking Wedge with Heat Generation/Absorption

Abstract:

In this paper, we have developed a mathematical model for the problem of unsteady hydromagnetic two dimensional flow and heat transfer of a viscous incompressible micropolar fluid over a heated permeable linearly stretching/shrinking wedge with heat generation/absorption. A set of similarity parameters is employed to convert the governing nonlinear partial differential equations into ordinary differential equations which are solved numerically using Nachtsheim-Swigert shooting iteration technique along with sixth order Runge-Kutta integration scheme. Comparisons with previously published work are performed and the results are found to be in excellent agreement. Numerical results are presented through graphs and tables and discussed them from the physical point of view. It is observed that the local skin friction coefficient (rate of shear stress) increases with the increase of the magnetic field parameter and the rate of heat transfer increases with the increase of the heat generation parameter.



Authors:

Alam, Shariful
Islam, T.
Uddin, Md. Jashim

http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/3391

2
Adaptive Algorithm-based DFE for Low PAPR Consumption and Effective Bandwidth Utilization of MIMO LTE OFDM

Abstract:

This paper focused on low PAPR consumption and efficient bandwidth optimization for MIMO LTE Downlink OFDM system excluding cyclic prefix (CP). The FDADFE is subjected to extract the performance based on specific parameters for better BER characteristics. The 3GPP LTE employs OFDM in downlink transmission, which experiences relentless inter-symbol interference (ISI) in high frequency selective fading channels. Although cyclic prefix (CP) is employed in the OFDM symbols to eliminate ISI completely, it consumes bandwidth and power. In this work, a frequency domain adaptive decision feedback equalizer (FDADFE) is introduced. The equalizer applies both RLS and LMS algorithms to adapt the filter coefficient that makes the system more convergent executing less time. Although complexity grows in the proposed system, the simulation results prove that, the FDADFE with OFDM system excluding CP in LTE outperforms the conventional OFDM system including CP in LTE in terms of both power and bandwidth efficiency with better BER performance.



Authors:
Munira, Sirajum
Haque, A.K.M. Fazlul
http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/3405

3
Variability of Acoustic Features of Hypernasality and it’s Assessment
Abstract:


Hypernasality (HP) is observed across voiced phonemes uttered by Cleft-Palate (CP) speakers with defective velopharyngeal (VP) opening. HP assessment using signal processing technique is challenging due to the variability of acoustic features across various conditions such as speakers, speaking style, speaking rate, severity of HP etc. Most of the study for hypernasality (HP) assessment is based on isolated sustained vowels under laboratory conditions. We measure the variability of acoustic features and detect HP using vowel /i/, /a/ and /u/ in continuous read speech with gradually increasing severity of HP of CP speakers. Linear predictive coding (LPC) method is used for acoustic feature extraction. In first part of our study, we observe the variation in acoustic parameters within and across vowel category with gradually increasing HP. We observe that inter-speaker variability in spectral features among CP subjects for vowel /i/ is 0.96, /a/ has 1.13 and vowel /u/ has 2.05. The inter-speaker variability measurement suggests that high back vowel /u/ is mostly affected and has the highest variability. High front vowel /i/ is least affected and has the lowest variability with HP. In the second part, ratio of vowel space area (VSA) of hypernasal and normal speech is calculated and used as a measure for HP detection. We observe that VSA spanned by CP subjects is 0.65 times less than isolated uttered Bangla nasal VSA and 0.43 times less than read speech uttered English oral VSA.


Authors:
Haque, Shahina
Ali, Md. Hanif
Haque, A.K.M. Fazlul

http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/3406

4
Customers’ perception of service quality of banking sectors in Bangladesh

Abstract:
Purpose The main purpose of the study is to find out the customer perception of service quality of banking sectors in Bangladesh and measure their relations with regard to the customer personal characteristics like gender, age, education and occupation. Design/methodology/approach The research method applied in this study is random sampling survey method. The data are analysed using descriptive statistics, one-way ANOVA, t-test and f-test. Findings The findings indicate that the overall customer perception is neutral level. Aspect like gender, age and occupation are found to be statistically significant, and education is not statistically significant. Originality/value The findings of the study will be a benchmark or the board for policymakers and implementers in torching the avenues of improvement in raising the level of customer satisfaction.


Authors:
Rouf, Md. Abdur
Mostafa Kamal
Iqbal, Mohammed Masum

Source:
http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/3434[/font]

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