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Search Results: 1 - 10 of 10338 matches for " Muhammad Ashikur Rahman "
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Evaluation of Anthelmintic Activity of Aqueous Leaf Extract of Clitoria ternatea Linn.
Kamrun Nahar,Muhammad Ashikur Rahman,Most. Nazma Parvin,Shammy Sarwar
Stamford Journal of Pharmaceutical Sciences , 2010,
Abstract: Development of anthelmintic resistance and high cost of conventional anthelmintic drugs led to the evaluation of medicinal plants as an alternative source of anthelmintics. The current study was aimed to evaluate the possible anthelmintic effects of crude fresh juice of leaves of Clitoria ternatea Linn. using of adult earth worm Pheretima Posthuma. Three concentrations (25, 50, 100mg/ml) of juice were studied for the determination of time of paralysis and death of the earth worms. Albendazole in same concentration as that of juice was considered as standard reference and normal saline as control. The result of the present study reveals that fresh juice significantly showed paralysis and also caused death of worms especially at higher concentraton of 100mg/ml, as compared to standard reference Albendazole.
A Discussion of the Suitability of Only One vs More than One Theory for Depicting Corporate Governance  [PDF]
Abdullah Al Mamun, Qaiser Rafique Yasser, Md. Ashikur Rahman
Modern Economy (ME) , 2013, DOI: 10.4236/me.2013.41005

Agency theory predicts that the Chief Executive Officer (CEO) and the chairman positions should be held by different individuals in order to protect shareholder’s interest. Though there are mixed evidences on CEO duality and firm performance, most research have found that there is negative relationship between CEO duality and firm performance.  Although, in the last decades of the twentieth century, agency theory became the dominant force in the theoretical understanding of corporate governance, it does not however cover all aspects of corporate governance. This paper aims to explore whether it is better to combine various theories in order to describe effective and good corporate governance or theorizing corporate governance based on one theory only. This will cover corporate governance theories which include agency theory, stakeholder theory, stewardship theory, and institutional theory.

On Reliable Transmission of Data over Simple Wireless Channels
Pawel Gburzynski,Bozena Kaminska,Ashikur Rahman
Journal of Computer Networks and Communications , 2009, DOI: 10.1155/2009/409853
Abstract: Standard protocols for reliable data transmission over unreliable channels are based on various Automatic Repeat reQuest (ARQ) schemes, whereby the sending node receives feedback from the receiver and retransmits the missing data. We discuss this issue in the context of one-way data transmission over simple wireless channels characteristic of many sensing and monitoring applications. Using a specific project as an example, we demonstrate how the constraints of a low-cost embedded wireless system get in the way of a workable solution precluding the use of popular schemes based on windows and periodic acknowledgments. We also propose an efficient solution to the problem and demonstrate its advantage over the traditional protocols.
Improved Self-Pruning for Broadcasting in Ad Hoc Wireless Networks  [PDF]
Raqeebir Rab, Shaheed Ahmed Dewan Sagar, Nazmus Sakib, Ahasanul Haque, Majedul Islam, Ashikur Rahman
Wireless Sensor Network (WSN) , 2017, DOI: 10.4236/wsn.2017.92004
Abstract: Reducing number of forwarding nodes is the main focus of any broadcasting algorithm designed for ad-hoc wireless networks. All reliable broadcasting techniques can be broadly classified under proactive and reactive approaches. In proactive approach, a node selects a subset of its neighbors as forwarding node and announces the forwarding node list in the packet header during broadcast. On the other hand, no such forwarding list is generated in reactive approach. Rather, a node (cognitively) determines by itself whether to forward the packet or not based on neighbor information. Dominant pruning and Self-pruning are two example techniques that fall under proactive and reactive approach respectively. Between the two methods, dominant pruning shows better performance than self-pruning in reducing number of forwarding nodes as they work with extended neighbor knowledge. However, appended forwarding node list increases message overhead and consumes more bandwidth. As a result, the approach becomes non-scalable in large networks. In this paper, we propose a reactive broadcasting technique based on self-pruning. The proposed approach dubbed as “Improved Self-pruning based Broadcasting (ISB)” algorithm completes the broadcast with smaller packet header (i.e., with no overhead) but uses extended neighbor knowledge. Simulation results show that ISB outperforms dominant pruning and self-pruning. Furthermore, as the network gets more spread and denser, ISB works remarkably well.
Rahman Md. Ashikur,Md. Hasanuzzaman,Rahman Md,Rahman Md. Mofizur
International Research Journal of Pharmacy , 2011,
Abstract: Phytochemical analysis of the dried leaves of Tabernaemontana divaricata (L). (Apocynaceae) indicated the presence of a steroids,tannins, saponins, gums and reducing sugar. The pharmacological interest of these compounds, coupled with the use of this plant in traditional medicine prompted the authors to check for its possible antibacterial activity. The extracts (ethanol, petroleum ether, diethyl ether, methanol and aqueous) were found to possess maximum potency against infectious pathogens Staphylococcus saprophyticus, Staphylococcus aureus, Enterococcus facealis, Staphylococcus pyogenes, Streptococcus agalactae, Salmonella typhi, Escherichia coli, Shigella boydii, Shigella dysenteriae and Pseudomonas aeruginosa. The zone of inhibition was observed with almost all bacteria with some exceptions. Minimum inhibitory concentrations of the extracts were found to be significant. The obtained results provide a support for the use of this plant in traditional medicine and its further investigation.
Enhanced Partial Dominant Pruning (EPDP) Based Broadcasting in Ad hoc Wireless Networks
Ashikur Rahman,Md. Endadul Hoque,Farzana Rahman,Sabuj Kumar Kundu
Journal of Networks , 2009, DOI: 10.4304/jnw.4.9.895-904
Abstract: In many applications of ad-hoc wireless networks, one often has to broadcast the same message to all nodes. The major goal of any broadcasting algorithm is to minimize the number of retransmissions, i.e., to accomplish the goal with the minimum amount of traffic in the network. In addition to reducing the bandwidth expense needed to convey the message to all the nodes, this objective will try to minimize the total amount of energy spent by the nodes on this communal task. This is of paramount importance in sensor networks, which are often built of disposable nodes, whose life-time is directly determined by the efficiency of their power management scheme. In this paper, we present a heuristic broadcast algorithm dubbed EPDP, for Enhanced Partial Dominant Pruning, and demonstrate its superiority, in terms of the total number of retransmissions, over other solutions addressing the same issue.
Managers’ Perception towards Dividends and Dividend Policy—Evidence from Bangladesh  [PDF]
Muhammad Mahbubur Rahman
Journal of Financial Risk Management (JFRM) , 2015, DOI: 10.4236/jfrm.2015.43012
Abstract: Dividend policy has been one of the most important research topics in modern corporate finance. From the practitioners’ viewpoint, dividend policy of a firm has implications for investors, managers, lenders and other stakeholders. The current study aims to examine critically the managers’ perception towards dividends and Dividend Policy of companies listed on Dhaka Stock Exchange (DSE) of Bangladesh. The study employed a practical survey on the perception of managers’ of twenty four companies to test the behavior of Bangladeshi listed firms towards dividend payout policy. Investigation of different dividend theories reveals that the bird-in-hand theory and the relevant value theory receive the highest support among the surveyed managers. It is also evident from the analysis that external factors related to the current financial market crises together with the state of the capital market and restrictions imposed by debt providers are all important factors in formulating dividend policy. The current study extends limited previous research based on questionnaire and survey related dividend policy. It thus provides new evidence from an emerging and fast growing economy like Bangladesh.
On Balanced k-coverage in Visual Sensor Network
Md. Muntakim Sadik,Sakib Md. Bin Malek,Ashikur Rahman
Computer Science , 2015,
Abstract: Given a set of directional visual sensors, the $k$-coverage problem determines the orientation of minimal directional sensors so that each target is covered at least $k$ times. As the problem is NP-complete, a number of heuristics have been devised to tackle the issue. However, the existing heuristics provide imbalance coverage of the targets--some targets are covered $k$ times while others are left totally uncovered or singly covered. The coverage imbalance is more serious in under-provisioned networks where there do not exist enough sensors to cover all the targets $k$ times. Therefore, we address the problem of covering each target at least $k$ times in a balanced way using minimum number of sensors. We study the existing Integer Linear Programming (ILP) formulation for single coverage and extend the idea for $k$-coverage. However, the extension does not balance the coverage of the targets. We further propose Integer Quadratic Programming (IQP) and Integer Non-Linear Programming (INLP) formulations that are capable of addressing the coverage balancing. As the proposed formulations are computationally expensive, we devise a faster Centralized Greedy $k$-Coverage Algorithm (CGkCA) to approximate the formulations. Finally, through rigorous simulation experiments we show the efficacy of the proposed formulations and the CGkCA.
Germanium Based Two-Dimensional Photonic Crystals: The Hexagonal and Honeycomb Lattices  [PDF]
Fairuz Aniqa Salwa, Muhammad Mominur Rahman, Muhammad Obaidur Rahman, Muhammad Abdul Mannan Chowdhury
Optics and Photonics Journal (OPJ) , 2019, DOI: 10.4236/opj.2019.93004
Abstract: The properties of two-dimensional (2D) photonic crystals (PCs) composed of germanium (Ge) are discussed. We investigate polarization-dependent photonic band diagrams (transverse electric and transverse magnetic polarizations), gap maps, surface plots, contour maps, etc. for 2D PCs with Ge rods in air and vice versa for two different lattices geometries, namely hexagonal and honeycomb lattices. The obtained graphs for the four possible combinations are presented in this paper. All the graphs depict clear photonic band gaps. The conditions for the largest TE and TM band gaps are described. The honeycomb lattice of Ge rods in air background offers a large complete photonic band gap Δω/ωm greater than 8% (for rod radius of r = 0.2 μm). Using these data, new Ge based photonic devices can be fabricated to confine, control and manipulate light in a more useful way.
A Novel Approach for Sugarcane Yield Prediction Using Landsat Time Series Imagery: A Case Study on Bundaberg Region  [PDF]
Muhammad Moshiur Rahman, Andrew J. Robson
Advances in Remote Sensing (ARS) , 2016, DOI: 10.4236/ars.2016.52008
Abstract: Quantifying sugarcane production is critical for a wide range of applications, including crop management and decision making processes such as harvesting, storage, and forward selling. This study explored a novel model for predicting sugarcane yield in Bundaberg region from time series Landsat data. From the freely available Landsat archive, 98 cloud free (<40%) Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) images, acquired between November 15th to July 31st (2001-2015) were sourced for this study. The images were masked using the field boundary layer vector files of each year and the GNDVI was calculated. An analysis of average green normalized difference vegetation index (GNDVI) values from all sugarcane crops grown within the Bundaberg region over the 15 year period identified the beginning of April as the peak growth stage and, therefore, the optimum time for satellite image based yield forecasting. As the GNDVI is an indicator of crop vigor, the model derived maximum GNDVI was regressed against historical sugarcane yield data, which showed a significant correlation with R2 = 0.69 and RMSE = 4.2 t/ha. Results showed that the model derived maximum GNDVI from Landsat imagery would be a feasible and a modest technique to predict sugarcane yield in Bundaberg region.
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