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Search Results: 1 - 10 of 402185 matches for " M. Shamim Kaiser "
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Performance Analysis of Optical Wireless Communication System Employing Neuro-Fuzzy Based Spot-Diffusing Techniques  [PDF]
Shamim Al Mamun, M. Shamim Kaiser, Muhammad R Ahmed, Md. Shafiqul Islam, Md. Imdadul Islam
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2048
Abstract: The spot-diffusing technique provides better performance compared to conventional diffuse system for indoor optical-wireless communication (OWC) system. In this paper, the performance of an OW spot-diffusing communication system using Neuro-Fuzzy (NF) adaptive multi-beam transmitter configuration has been proposed. The multi-beam transmitter generates multiple spots pointed in different directions, hence, forming a matrix of diffusing spots based on position of the receiver and receiver mobility. Regardless of the position of the transmitter and receiver, NF controller target the spots adaptively at the best locations and allocates optimal power to the spots and beam angle are adapted in order to achieve better signal-to-noise plus interference ratio (SNIR). Maximum ratio combining (MRC) is used in the imaging receiver. The proposed OW spot-diffusing communication system is compared with other spot-beam diffusion methods proposed in literature. Performance evaluation revels that the proposed NF based OW spot-diffusing communication system outperforms other spot-beam diffusion methods.
Energy Efficient System for St Martin s Island of Bangladesh
M. Shamim Kaiser,S.K. Aditya
Journal of Engineering and Applied Sciences , 2012,
Abstract: St Martin`s is one of the most beautiful Tourist Islands in Bangladesh where grid connected electric system for the inhabitants will not be possible to establish even in future. Diesel, Kerosene and wood are the main fuels for fulfilling the energy demand. Solar and Wind resources are the hybrid options for the Island. HOMER, a software for optimization of renewable based hybrid systems, has been used to find out the best technically viable renewable based energy efficient system for different numbers of households-1, 10, 20, 30, 40 and 50. It shows that per unit (KWh) cost of energy varies from 48 to 19 taka.
Radio Resource Allocation for Heterogeneous Services in Relay Enhanced OFDMA Systems
M. Shamim Kaiser,Kazi Mohiuddin Ahmed
Journal of Communications , 2010, DOI: 10.4304/jcm.5.6.447-454
Abstract: We propose a priority based resource allocation algorithm for heterogeneous services in the relay enhanced OFDMA downlink systems. The aim is to maximize the system throughput while satisfying the quality of service (QoS) requirements of heterogeneous services, comprising real time (RT) and non real time (NRT) services. The base station (BS) allocates resources dynamically to the users in a prioritized manner. The priority parameter depends on the channel condition, QoS requirement and data buffer information. We propose a suboptimal algorithm to reduce the computational complexity. The simulation results are compared with the fixed as well as dynamic resource allocation algorithms proposed in different researches. Our proposed scheme reduces the outage probability of the system and increases the system throughput.
Wind Energy Assessment for The Coastal Part of Bangladesh
M. Shamim Kaiser,M. Arifur Rahman,M. Mostafizur Rahman,S.A. Sharna
Journal of Engineering and Applied Sciences , 2012,
Abstract: Earlier measurement and study of wind speed for the coastal part of Bangladesh showed that some of the areas of this part would be useful for wind power generation. But till now no measurement at the hub height of wind machine has yet done. Data has been collected from different sources and analysis has been done using logarithmic law and micro scale modeling software, WAsP for wind energy assessment over the coastal part. It has been found that the speed varies from 4m/s to 5.7 m/s at a height of 50m above ground level depending on the land type. Wind power density varies from 100 to 250 w/m2 indicate the wind power can play an important role in the energy sector.
Hybrid Options Analysis for Power Systems in St. Martin s Island
Shamim Kaiser,A.K.M Fazlul Haque,M. Arifur Rahman,M. Mostafizur Rahman,Abu Md. Zafor Alam
Journal of Engineering and Applied Sciences , 2012,
Abstract: St Martin s is one of the most beautiful Tourist Islands in Bangladesh where grid connected electric system for the inhabitants will not be possible to establish even in future. Diesel, Kerosene and wood are the main fuels for fulfilling the energy demand. Solar and Wind resources are the hybrid options for the Island. HOMER, a software for optimization of renewable based hybrid systems, has been used to find out the best technically viable renewable based energy efficient system for different numbers of households-1, 20and 50. It shows that per unit (KWh) cost of energy varies from 39.8 to 13.9 taka.
An Optimal Operating Strategy of an Integrated Energy System for a Typical Rural Village in Bangladesh
M. Shamim Kaiser,M. Arifur Rahman,M. Mostafizur Rahman,A.K.M. Fazlul Haque,M. Abu Taher,S.K. Aditya
Journal of Engineering and Applied Sciences , 2012,
Abstract: Hybrid energy system is an excellent solution for power generation in rural areas where the grid is infeasible. Such a system incorporates a combination of one or several energy sources such as solar PV, wind energy units, diesel generators etc. This study discusses various system components for remote area power supplies and then proceeds to an optimal operating strategy of an integrated system for a typical rural village at Kutubdia in Bangladesh. In order to determine the hourly operating states of a hybrid system more accurately, practical mathematical models characterizing PV module, wind generators are used. Battery and diesel generator are used as back up power sources. Quasi Newton algorithm is applied for optimizing the operation of wind and PV integrated energy systems. The result of the case study shows that the cost of electricity is 23 Tk/kWh for a PV/wind hybrid system.
Geochemistry of Palaeoproterozoic Rocks of Aravalli Supergroup: Implications for Weathering History and Depositional Sequence  [PDF]
Pavanesh K. Singh, M. Shamim Khan
International Journal of Geosciences (IJG) , 2017, DOI: 10.4236/ijg.2017.810074
Abstract:
The Paleoproterozoic Aravalli Supregroup of rocks, hosted in Aravalli Craton of NW shield, is deposited in shallow and deep water conditions. The major lithologies are phyllites and quartzites with significant components of greywacks and dolomite. Geochemical indices in particular, CIA (Chemical Index of Alteration) values (avg. phyllites: 51.6 - 81.5, avg. quartzites: 57.4 - 95.5) calculated from the data of clastic rocks of ASG suggest minimum to highly intense weathering in the source region. Other indices including PIA, CIW and ICV along with plot patterns on the A-CN-K diagram also nearly endorse CIA based interpretation. These rocks possess relatively high Th/U ratios compared to that found in fresh igneous rocks or their high grade metamorphic equivalents. This high Th/U ratio is neither a source inheritance nor a result of oxidation state rather a manifestation of Th hosting mineral accumulation through sorting. Viewed in the context of present stratigraphic succession, the weathering history adduced from geochemistry does not seem compatible but matches well with earlier classification scheme wherein the evolution of Aravalli Supergroup was considered episodic.
Antibiotic Prescription Patterns in the Management of Open Fractures at Mulago Hospital in Kampala
JWM Kigera, M Shamim
East and Central African Journal of Surgery , 2012,
Abstract: Background: Open fractures are contaminated and may result in infection. The use of antibiotics has greatly reduced the risk of infection. We conducted a study in a large teaching hospital to evaluate the use of antibiotics in the management of open fractures. Methods: A prospective study of adult patients with open fractures was conducted. Details of antibiotic use were extracted from the patient charts while details of the injury were determined by interviewing patients. Data was analysed using SPSS v 11.5. Results: Majority of the patients were involved in road traffic accidents and were mainly pedestrians. Only about half of the patients had antibiotics started while in the accident and emergency department and only about half of the patients received tetanus toxoid prophylaxis. Conclusion and Recommendations: The antibiotic prescription patterns are at variance with recommendations in literature. There is need to adopt hospital guidelines in the use of antibiotics and also the use of checklists to ensure patients receive all necessary medications before leaving the accident and emergency setting.
Corrosion Behaviour of Aluminium Engine Block in 3.5% NaCl Solution  [PDF]
M. S. Kaiser, Swagata Dutta
Journal of Materials Science and Chemical Engineering (MSCE) , 2014, DOI: 10.4236/msce.2014.210008
Abstract:

In the present work, the corrosion behavior of aluminium alloy engine block in 3.5% NaCl solution was studied. The work was carried out using conventional gravimetric measurements and complemented by scanning electron microscopy (SEM) and X-ray analyzer (EDX) investigations. The results obtained indicate that the main process the alloy undergoes, under the medium of exposure studied, is related to localized corrosion that takes place as a consequence of the process of alkalinization around the cathodic precipitates existing in the alloy. The alloy suffers a process of corrosion localized to the area surrounding the precipitates of the Al (Si, Mg) and Al-Mg, which resulted in hemispherical pits. This identification was confirmed by SEM and EDX analysis. No evidence was found of the formation of crystallographic pitting for exposure times up to 54 days. Gravimetric analysis confirmed that with varying exposure periods the weight loss of the alloy increases and the corrosion rate decreases with time.

Exchange Potential for excited states: A self- consistent DFT calculation
Md Shamim,M K Harbola
Physics , 2011,
Abstract: An LDA exchange potential is proposed for excited states and to test this potential we apply it to the excited states of atomic system. The potential is an approximate functional derivative of an accurate exchange energy functional for excited states. We show that the potential satisfies Levey- Perdew theorem for exchange energy and janak theorem for orbital energy very well in excited state cases. The potential is the first of its kind for excited state and can easily be generalized to other excited states of interest. We compare our results with those of other approaches reported in the literature.
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