Self-organized HGBBDSA Approach for the Power Allocation in OFDMA-based Heterogeneous Network

Mohammad Kamrul Hasan,Ahmad Fadzil Ismail,Shayla Islam,Wahidah Hashim 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.7

This paper studied the power allocation and downlink interference issues in orthogonal frequency-division-multiple-access (OFDMA) system to mitigate the interference issues. In Orthogonal Frequency Division Multiplexing Access (OFDMA) frameworks, resource allotment to the subcarrier is crucial attributable to the deficient assets accessible at the base station. In OFDMA, subcarrier and power distribution are not separate, along with these lines this two portion are not self-overseeing. This paper examines the power allo-cation approach through exploring the HGBBDSA approach. The integration of GA with Biogeography Based Optimization algorithm benchmarked over the Particle Swarm Op-timization (PSO). The both of the algorithms cross usefulness is evaluated and looked at the exhibitions in Heterogeneous Network (HetNet). The reenactment results demonstrate that the HGBBDSA approach efficiently allocates the power than that of existing PSO approach.

A comprehensive analysis of degree based condition for Hamiltonian cycles

Hasan, Md. Kamrul,Kaykobad, Mohammad,Lee, Young-Koo,Lee, Sungyoung Elsevier 2010 Theoretical computer science Vol.411 No.1

<P><B>Abstract</B></P><P>Since finding whether a graph has a Hamiltonian path or Hamiltonian cycle are both NP-complete problems, researchers have been formulating sufficient conditions that ensure the path or cycle. Rahman and Kaykobad (2005) <ce:cross-ref refid='b2'>[2]</ce:cross-ref> presented a sufficient condition for determining the existence of Hamiltonian path. Three recent works–Lenin Mehedy, Md. Kamrul Hasan, Mohammad Kaykobad (2007) <ce:cross-ref refid='b3'>[3]</ce:cross-ref>, Rao Li (2006) <ce:cross-ref refid='b4'>[4]</ce:cross-ref>, Shengjia Li, Ruijuan Li, Jinfeng Feng (2007) <ce:cross-ref refid='b5'>[5]</ce:cross-ref>–further used the same or similar condition to ensure Hamiltonian cycle with some exceptions. The three works, along with their unique findings, have some common results. This paper unifies the results and brings them under Rahman and Kaykobad’s condition.</P>

Effects of reforestation approaches, agroforestry and woodlot, on plant community composition, diversity and soil properties in Madhupur Sal forest, Bangladesh

Hasan Mohammad Kamrul,Islam Md. Tariqul,Akter Rojina,Roshni Nasima Akther 한국생태학회 2022 Journal of Ecology and Environment Vol.46 No.3

Background: Increasing land demands for food production have led to biodiversity loss and land degradation in the Madhupur Sal forest. Reforestation activities such as agroforestry and woodlot plantation support the conservation of diversity, restoration of forest and prevention of soil erosion in degraded natural Sal forest. Knowing about these reforestation activities, this study is needed to compare the species composition, richness, and soil nutrients of these two plantation activities to the natural Sal forest in the degraded Madhupur Sal forest in Bangladesh. Results: The analysis showed that in between the reforestation activities, the highest Shannon- Wiener index (1.79), evenness (0.60) and Simpson’s index (0.79) were found in the agroforestry site compared to the woodlot plantation site. On the contrary, the highest species richness (n = 14), tree basal area (19.56 m2 ha−1), Margalef’s index (1.96) were recorded in woodlot plantation than in the agroforestry site. We observed that at 0–15 cm depth, soil organic matter (2.39%), total nitrogen (0.14%), available phosphorous (62.67 μg g−1) and exchangeable potassium (0.36 meq/100 g) in agroforestry plots were significantly higher compared to other forest sites. At topsoil (15–30 cm depth), soil organic matter (1.67%) and available phosphorous (21.09 μg g−1) were found to be higher in agroforestry site. Conclusions: Both reforestation approaches improved soil function, although woodlot plantation had the higher species richness. Therefore, plantation activities by the sustainable implementation of these two practices are the best alternative to restore the biodiversity, richness and conserve soil fertility in the Madhupur Sal forest of Bangladesh.

Biogeography-based Interference Mitigation Scheme for OFDMA System in Heterogeneous Network

Mohammad Kamrul Hasan,Ahmad Fadzil Ismail,Aisha-Hassan Abdalla,Wahidah Hashim,Shayla Islam 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.10

In Heterogeneous Network (HetNet), the small base station such as femtocells are deployed in indoor and multiple business complexes in order to extend the coverage and capacity. The deployment of co-channel (i.e. shared channel) for femtocells along with macrocell induces the severe interference issues. This is because of effects on SINR and thereby capacity become deteriorated. Therefore, this paper investigates the interference mitigation techniques and come out with a proposal to improve the Signal to Interference Noise Ratio (SINR) performance as well as total capacity in Heterogeneous Network (HetNet).The simulation results show that the achieved capacity is maximized than the existing technique.

Investigation of Enhanced Particle Swarm Optimization Algorithm for the OFDMA Interference Management in Heterogeneous Network

Mohammad Kamrul Hasan,Ahmad Fadzil Ismail,Wahidah Hashim,Shayla Islam 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.9

In orthogonal frequency division multiplexing Access (OFDMA) systems resource allocation to the subcarrier is essential owing to the insufficient resources available at the base station. In OFDMA, subcarrier and power allocation are not separate; thereby this two allocation are not self-governing. This paper proposes the subcarrier allocation approach through investigating previous methods, and also the Enhanced Particle Swarm Optimization (PSO) algorithm is analyzed. The both of the algorithms cross functionality is analyzed and compared the performance of the subcarrier allocation of OFDMA systems in Heterogeneous Network (HetNet). The simulation results show that the PSO approach efficiently allocates the OFDMA subcarriers.

Direct Mean Strain Estimation for Elastography Using Nearest-Neighbor Weighted Least-Squares Approach in the Frequency Domain

Hasan, Md. Kamrul,Anas, Emran Mohammad Abu,Alam, S. Kaisar,Lee, Soo Yeol Elsevier 2012 Ultrasound in medicine & biology Vol.38 No.10

<P>Ultrasound elastography is emerging with enormous potential as a medical imaging modality for effective discrimination of pathological changes in soft tissue. It maps the tissue elasticity or strain due to a mechanical deformation applied to it. The strain image most often calculated from the derivative of the local displacement field is highly noisy because of the de-correlation effect mainly due to unstable free-hand scanning and/or irregular tissue motion; consequently, improving the SNR of the strain image is still a challenging problem in this area. In this paper, a novel approach using the nearest-neighbor weighted least-squares is presented for direct estimation of the 'mean' axial strain for high quality strain imaging. Like other time/frequency domain reported schemes, the proposed method exploits the fact that the post-compression rf echo signal is a time-scaled and shifted replica of the pre-compression rf echo signal. However, the elegance of our technique is that it directly computes the mean strain without explicitly using any post filter and/or previous local displacement/strain estimates as is usually done in the conventional approaches. It is implemented in the short-time Fourier transform domain through a nearest-neighbor weighted least-squares-based Fourier spectrum equalization technique. As the local tissue strain is expected to maintain continuity with its neighbors, we show here that the mean strain at the interrogative window can be directly computed from the common stretching factor that minimizes a cost function derived from the exponentially weighted windowed pre- and post-compression rf echo segments in both the lateral and axial directions. The performance of our algorithm is verified for up to 8% applied strain using simulation and experimental phantom data and the results reveal that the SNR of the strain image can be significantly improved compared to other reported algorithms in the literature. The efficacy of the algorithm is also tested with in vivo breast data known to have malignant or benign masses from histology.</P>

Robust strain-estimation algorithm using combined radiofrequency and envelope cross-correlation with diffusion filtering.

Hussain, Mohammad Arafat,Alam, S Kaisar,Lees, Soo Yeol,Hasan, Md Kamrul Academic Press 2012 Ultrasonic imaging Vol.34 No.2

<P>In ultrasound elastography, the strain in compressed tissue due to external deformation is estimated and is smaller in harder than softer tissue. With increased stress, the nonaxial motions of tissue elements increase and result in noisier strain images. At high strain, the envelope of the rf signal exhibits robustness to signal decorrelation. However, the precision of strain estimates using envelope signals is much worse compared to that using the rf signals. In this paper, we propose a novel approach for robust strain estimation by combining weighted rf cross-correlation and envelope cross-correlation functions. An applied strain-dependent piecewise-linear-weight is used for this purpose. In addition, we introduce nonlinear diffusion filtering to further enhance the resulting strain image. The results of our algorithm are demonstrated for up to 10% applied strain using a finite-element modelling (FEM) simulation phantom. It reveals that the elastographic signal-to-noise ratio (SNRe) and the elastographic contrast-to-noise ratio (CNRe) of the strain images can be improved more significantly than with other algorithms used in this paper. In addition, comparative results in terms of the mean structural similarity (MSSIM) using in vivo breast data show that the strain image quality can be improved noticeably by the proposed method than with the techniques employed in this work.</P>

Removal of ring artifacts in CT imaging through detection and correction of stripes in the sinogram

Anas, Emran Mohammad Abu,Lee, Soo Yeol,Hasan, Md. Kamrul Institute of Physics in association with the Ameri 2010 Physics in medicine & biology Vol.55 No.22

<P>Due to malfunctioning and mis-calibration of cells in digital x-ray detectors as well as impurities on the scintillator screens, stripe artifacts arise in the sinogram which in turn generate ring artifacts in the reconstructed x-ray computed tomography images. In this paper, a novel technique is proposed for the detection and removal of stripe artifacts in a sinogram with a view to suppress the ring artifacts from the tomographic images. To accurately detect the stripe creating pixels using a derivative-based algorithm, at first the sinogram is windowed to create a sub-sinogram by keeping the pixel of examination at the center position in the sub-sinogram. The other pixels in the sub-sinogram are selected from a polyphase component of the sinogram. A new mathematical index is proposed here to isolate the strong and weak ring-generating stripes from the good ones. For the correction of strong ring artifacts resulting from the defective detector elements and dusty scintillator crystals, 2D variable window moving average and weighted moving average filters are proposed in this work. On the other hand, a conventionally trusted constant bias correction scheme is adopted to correct the responses of the mis-calibrated detector elements. To evaluate and compare the performance of the proposed algorithm, real micro-CT images acquired from two flat panel detectors under different operating conditions are used. Experimental results show that the proposed method can remove ring artifacts more effectively without imparting noticeable distortion in the image as compared to a recently reported technique in the literature.</P>

Implementation of Server Handover for Live Streaming Application during High Traffic with Bitrate Adaptation

Rajina R. Mohamed,Wahidah Hashim,Ahmad Fadzil Ismail,Khalid M.Abdilahi,Mohammad Kamrul Hasan 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.8

As the rate of internet users is increasing on a daily basis, a tremendous amount of these users are accessing online streaming websites and applications. This paper proposes a live streaming architecture that supports traffic balancing during peak times and bitrate adaptation. Rather than replicating content on multiple servers, we implemented traffic balancing by assigning a temporary regional server to manage the traffic at regional area. Bitrate adaptation at server side was also proposed and implemented to provide a fair video quality to all users. Through a few tests that has been run on the testbed, we can see the live video streaming was move seamlessly from one server to another server with an acceptable video quality among the users.

A Numerical Framework for the Analysis of Handoff Delay Component in Proxy NEMO Environment

Shayla Islam,Aisha-Hassan A. Hashim,Azween Abdullah,Mohammad Kamrul Hasan 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.8

Network Mobility Basic Support Protocol (NEMO-BSP), the existing IETF standard for mobile network support, signifies an important portion for future heterogeneous wireless access networks. The reason is to provide continuous Internet connectivity during movement of Mobile Router (MR) in NEMO. This paper conducted a quantitative analysis on the handoff delay component of NEMO-BSP as well as its existing enhancements, i.e., Fast NEMO (F-NEMO) handoffs, and an Extension of F-NEMO (EF-NEMO), using the numerical framework. The mathematical scenario includes two access routers, one local home agent and up to 20 MRs that interrelate by two different wireless access networks are mainly WiFi and WiMAX. The analysis offers quantitative outcomes of the performance enhancements achieved via the proposed improvements concerning handoff delay gain, packet loss, and packet loss ratio. The numerical results assist in understanding the influence of link switching delay, mobility rate, and radius on the handoff delay gain, packet loss, and packet loss ratio. The results of this analysis will also be aided to pick an appropriate mobility management scheme for Proxy NEMO environment.