2016

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A Brief Study of Nanowire FET Biosensor and Analysis of Electrical Properties of Si and ZnO Gate-all-around Nanowire FET
(IUT, EEE, 2016-11-20) Reza, Syed Zahin
The detection of biological and chemical species is central to many areas of healthcare and the life sciences, ranging from uncovering and diagnosing disease to the discovery and screening of new drug molecules. Hence, the development of new devices that enable direct, sensitive, and rapid analysis of these species could impact humankind in significant ways. Devices based on nanowires are emerging as a powerful and general class of ultrasensitive, electrical sensors for the direct detection of biological and chemical species. Development of nanobiosensor is one of the most recent advancement in the field of Nanotechnology. Research on optical nanobiosensors with submicron-sized dimensions has opened new horizons for intracellular measurements. Taking advantage of the unique properties of the nanomaterials, faster and sensitive nanobiosensors can be developed. Apart from being sensitive and fast, the studies related to nanobiosensors have geared their efforts towards the development of nanomaterial-based sensors that are affordable, robust and reproducible. The nanobiosensors are equipped with immobilized bioreceptor probes, e.g., antibodies, enzyme substrate. Laser excitation is transmitted to photometric system in the form of optical signal (fluorescence). Nanobiosensors will revolutionize the future of disease diagnosis. The present review discusses the basic concepts, developments and the biomedical applications of nanobiosensors.
A review of energy efficient ternary content addressable memory (TCAM) circuits for network application
(IUT, EEE, 2016-11-20) Nafiur, Rahman; Rumman, K.M.; Raihan, S.M. Rakib
Ternary content addressable memory [TCAMs) are especially popular in network routers for packet forwarding and classification, but they are also beneficial in a variety of other applications that require high speed table lookup. They are used to implement lookup-table function in a single clock cycle using dedicated comparison circuitry. Although it has many attractive features, higher power consumption is very crucial drawbacks of TCAMs. Hence, a great amount of efforts have to give to design T-CAMs without doing any compromise with its speed and voltage margin. Match line sense amplifiers (MLSAs) consume a significant portion of the TCAM power for match detection .This works compares circuit techniques for reducing TCAM power consumption
A review on supercapacitor & its application
(IUT, EEE, 2016-11-20) Rahman, Md. Mahbubur; Al Joha, Md. Abdullah; Ahsan, Shadman
Capacitors are commonly used in electronic resonance circuits; however, capacitors have not been used for storing large amounts of electrical energy in electrical circuits. Also they are not known to be long lasting. Thus appears the need of supercapacitor with variety of electrodes, offering high power density, fast charging & elongated life-cycle. Highly conducting and porous carbon nanotube (CNT) networks are popular as the sole electron conducting material in supercapacitors. The high conductivity of CNT networks and the high surface area allow the replacement of both the metallic current collector and the active material that forms one side of the electrochemical double layer. The combination of both functions in one single layer leads to lightweight charge storage devices that can be manufactured using simple and cheap room temperature methods. In case of solid-state supercapacitor, device fabrication is done by a simple vacuum thermal evaporation method, which allows not only a multilayer stacking structure to further enhance the capacitance, but also permits the supercapacitor to be easily incorporated with other electronic devices, showing interesting characteristics for both fundamental study and practical applications. supercapacitors are being used to increase the efficiency of hybrid electric vehicles in several ways. Aging of a capacitor is a topic to be concerned about. The voltage difference in cells and temperature tend to shorten the life span. Methods are being developed to tackle this problem. Until recently, supercapacitors were relegated to fairly mundane applications such as memory protection and internal battery backup, but in the last few years the application space has broadened significantly into hybrid vehicles, smartphones, and energy harvesting. New technologies on the horizon promise to bring supercapacitors into full competition with rechargeable batteries
Adaptive Control of CRE with Proportional Fair Resource Scheduling in LTE HetNets
(IUT, EEE, 2016-11-20) Al Islam, Md. Nafee; Arman, Shahed; Bhuiyan, Rokibul Hasan
Cell range extension (CRE) has been used as a method to increase the area under the small cell and balance the loads between small and large cell by adding a cell selection offset (CSO) to small cells in heterogeneous network deployment. Previously most of the other literatures considered CSO setting for round robin resource scheduling but in this study we have considered Proportional Fair Resource Scheduling to make the computations realistic. This work paves a way to achieve better load balancing by selecting a CSO value to have equal average cell data rates by means of proportional fair resource scheduling in LTE HetNets. Simulation results indicate that this method can achieve a better average user throughput in networks with different densities of small cells
Analytical Modelling of Transverse Flux Motor Using Magnetic Equivalent Circuit and 3D FEM Analysis
(IUT, EEE, 2016-11-20) Rahman, Sheikh Ifatur; Mubin, GNM Mushfiqur; Hasan, Tajbir
This thesis presents the design one unique single phase transverse flux machines (TFM) with one rotor disk. The necessity to use three dimensional finite element analysis (FEA) justified by analyzing a U-core, which is a fundamental element of the magnetic circuit in the TFM. The analysis is performed under different conditions with different methods viz. MEC analytical method and 3D FEA. Analytical models for the modular TFM are derived in order to calculate the fluxes in the core created by magnets and the current in the stator winding, in terms of its geometrical parameters. The calculated fluxes are used to calculate the torque of the machine. The accuracy of the analytical models are evaluated by comparing the results with that obtained from 3D FEA for different loading conditions. The analytical models are then used to obtain some optimized geometrical configurations by assigning a range of to each geometrical parameter. By applying design constraints such as a low utilization of the magnetic cores and current densities than 5 A/mm2 in the conductors, some of the geometrical configurations can be eliminated.
Automatic generator start and change over module
(IUT, EEE, 2016-11-20) Andrew, Mohammed Daniel; Dankaura, Hussaini Musa; Moussa, Moussa Abdi
Categorizing M2M Devices for Efficient Random Access in LTE
(IUT, EEE, 2016-11-20) Chowdhury, Rakib Hasan; Shadman, MD. Rashik; Hossain, Shakil
In this paper, we propose a dynamic allocation scheme of random access channel (RACH) slots for categorized machine-to- machine (M2M) devices, in which delay-sensitive services coexist with delay-tolerant ones. Our scheme aims at alleviating the overload and congestion of machine-type (MTC) communication as well as satisfying both delay-sensitive and delay-tolerant services. In order to make full use of RA slots, our proposed scheme adopts a categorized machine-to-machine (M2M) networking, where the M2M devices categorized into several types based on their delay sensitivity and priority. The most delay sensitive and high priority devices will be included in Type 1. Other devices will be categorized in Type 2, Type 3 etc. based on their delay sensitivity and priority. Type 1 will be allocated the maximum number of RA slots. Other types will be provided less number of RA slots. Simulation result shows that our proposed scheme realizes the remarkable increase in improving the number of packets arriving successfully and completing RA.
Comparative Study of CZTS Thin Film Solar Cell with Different Buffer and Window Layer
(IUT, EEE, 2016-11-20) Tousif, Md. Noumil; Ferdous, A. A.; Mohammad, Sakib
Energy conversion efficiency is a major issue for photovoltaic cells today. Researchers are continuously trying to improve the efficiency level of photovoltaic devices by introducing new materials and advanced concepts. The target is to reach a high efficiency level within affordable cost, which will lead to a mass generation of electricity using photovoltaic devices. The performance of CZTS solar cell using two different buffer layers was numerically simulated. We used CdS (Cadmium Sulfide) and In2S3 (Indium Sulfide) alternately as buffer layer. Performance was recorded for different thicknesses of CZTS absorber layer, different thicknesses of buffer layer and different values of acceptor density of CZTS. Best efficiency was 22.66% (with VOC= 0.9114 V, JSC= 28.68 mA/cm2, FF=86.68%) which was obtained with CdS as buffer layer. The thickness of CZTS layer was 5 μm and the acceptor density was 2*1014 cm-3. Varying the thickness of buffer layer does not have any significant effect on the performance of this solar cell. Our simulated model can be used for fabricating solar cells with higher efficiency.
Design and simulation of plasmonic waveguide with periodic corrugations
(IUT, EEE, 2016-11-20) Niaz, Mohammad Rakeen; Nishat, Mirza Muntasir; Arif Hossain, Mohammad
The key performance parameters of an MIM(metal-insulator-metal) surface plasmonic waveguide having periodic corrugations has been investigated. The transmittance, taking into account a wide range of optical wavelength was demonstrated by rigorous numerical calculations against the variation of different structural aspects. The results indicate that a very satisfactory filtering characteristic can be achieved by this variation of the parameters The output of this investigation has the potential to develop ultra-compact photonic filters for higher integration.
Development of Birth-Death update rule using evolutionary game theory for self organised data aggregation technique in delay tolerant network
(IUT, EEE, 2016-11-20) Matin Khan, Mohammad Abdullah; Rahman, Taseef; Muhaisan, Md. Muhtady
EEBCDA Co-MIMO scheme for wireless sensor networks
(IUT, EEE, 2016-11-20) Dhrubo, Tanvir Islam; Ahmed, Sarwar; Rahman, Rafayat Razi; Tholaal, Ahmed; Haris, Muhammad
This thesis work is focused on the Cooperative multiple input multiple output (CO-MIMO). In radio, multiple-input and multiple-output, or MIMO , is a method for multiplying the capacity of a radio link using multiple transmit and receive antennas to exploit multipath propagation. At one time, in wireless the term "MIMO" referred to the use of multiple antennas at the transmitter and the receiver. In modern usage, "MIMO" specifically refers to a practical technique for sending and receiving more than one data signal simultaneously over the same radio channel by exploiting multipath propagation. MIMO is fundamentally different from smart antenna techniques developed to enhance the performance of a single data signal, such as beamforming and diversity. MIMO is often traced back to 1970s research papers concerning multi-channel digital transmission systems and interference (crosstalk) between wire pairs in a cable bundle: AR Kaye and DA George (1970), Branderburg and Wyner (1974), and W. van Etten (1975, 1976). Although these are not examples of exploiting multipath propagation to send multiple information streams, some of the mathematical techniques for dealing with mutual interference proved useful to MIMO development. EEBCDA is one of the efficient cluster based to wireless sensor networks (WSN) protocols. It solves unbalanced energy consumption of cluster based networks by clustering based on energy consumption of the clusters. This results in more balanced energy consumption among the clusters. In this thesis we combine EEBCDA with cooperative MIMO to make EEBCDA more energy efficient on longer distances. In EEBCDA MIMO scheme, the residual energy of each node is considered in choosing CHs for clustering and in case of cooperative nodes selection. Simulation results demonstrate that this results less energy consumption and in turn better overall life time of nodes EEBCDA SISO.
Exponential transformation and modified nth root exponential transformation for peak to average power ratio reduction in OFDM system
(IUT, EEE, 2016-11-20) Ahmed, Raihan Uddin; Chowdhury, Mahir Asef; Solaiman, Mohammad
Due to the High data rate requirement of modern cellular network, multicarrier modulation (MCM) is now becoming more and more mandatory for Wireless Networks. Orthogonal Frequency Division Multiplexing (OFDM) has proved to a promising MCM technology for application requiring High Data Rate. For instance, in the case of 3GPP and 4G cellular networks, OFDM is used for its huge spectral efficiency and zero Inter Symbol Interference (ISI). However OFDM has a major drawback in terms of Peak to Average Power Ratio (PAPRR) and Inter Carrier Interference (ICI). The resulting peaks from superposition sum, creates high peaks in the signal, which drives the Amplifier saturation region. The saturation region has non-linear characteristics which creates Out of Band (OOB) radiations that are filtered resulting in a data loss. To restrict the amplifier from driving in to the saturation region, high Power Amplifiers (HPAs) must be used to keep the signal In Bound. Thus the power dissipation increases and the battery drains out quickly. Unless the peak power problem of OFDM is not addressed, then the power inefficiency of the system surpasses the advantage of Higher Data Rate. Researches, over the years have proposed versatile methods for reducing the PAPRR of OFDM signals. The methods are categorized using numerous parameters such as computational complexity, necessity of Side Information (SI), noise performance, implementation process and so on. Performance of each method is affected by the parameters considered for the transmission. Because of this, the generality of PAPRR Reduction implementation cannot be defined. Some of the methods involve the scrambling of signal like Partial Transmit Sequence (PTS), Selective Mapping (SLM) and Active Constellation Extension (ACE), while others employ signal distortion technique as Iterative Clipping and Filtering, Tone Injection (TI) and Tone Rejection (TR). In this Thesis PAPRer, we have explored some non-conventional methods for the purpose of PAPRR reduction. Our first proposal involves an exponential conversion the time domain signal in order to achieve lower PAPRR values. The method introduces no further need of SD and any change of phase or frequency whatsoever. The computation of the exponential equivalent is simple and requires less numbers of complex addition and multiplication resulting in low complexity. Next proposed method is a modification of the exponential conversion using the signal mean square average to scale the transformed signal. Combining this modified proposal with n times root, we get even higher PAPRR reduction. The reduction performance is illustrated as Complementary Cumulative Distribution Function (CCDF) vs PAPRR plot using MATLAB. The advantages of the proposed models over the current state of the art technologies are demonstrated by tabulating the reduction results achieved for various methods. Though the better reduction result is achieved, there exists a tradeoff between the PAPRR and Bit Error Rate (BER). The optimization of BER is excluded from the capacity of this Paper, though a representation is drawn. Mathematical expression and Simulation results of the proposals outperform the result of both PTS and SLM.
Forward Handover in LTE Heterogeneous Network
(IUT, EEE, 2016-11-20) Tanzil Bin, Hassan; Alam, Tahmid; Faisal, Sakib; Khan, Abdul Munim
One of the essential targets of LTE HetNet is to provide seamless and fast handover from one cell to another to achieve a strict delay requirement while, at the same time, keeping network management as simple as possible. Hence, the decision to trigger a handover is very important in the design of handover process. Handover performance in heterogeneous networks deployments is not as good as in homogenous deployments. The handover triggering is highly depended on the UE speed, which means that as the UE speed changed, the handover triggering time is correspondingly varied. It means high speed user equipment (UE) suffers much higher handover failure rate than low speed UE. Determining a more accurate handover triggering point is a critical issue. Too late handover triggering caused by UE speed change will lead to handover failure. For handover to be successful, it requires to choose handover parameters correctly and optimize their setting. In this paper we proposed a forward handover scheme that allows pico to macro cell handover process to be fast. Because of faster handover procedure we can ensure better RSRP for the user moving at high velocity at the cell edge region.
Genaration of electricity by pedal power
(IUT, EEE, 2016-11-20) Patowary, Tanjimul Hoque; Hasan, Mahadi; Karim, Kazi Shahariar
It is known that the supply of fossil fuels are scarce and their usage as energy source cause environmental degradation ,in addition to this as the world population increases the energy demand is also increasing day by day, so we are in a search of new renewable energy sources. We are trying to generate power at small levels by using bicycle pedal . Generator attached to the cycle pedal can serves as a mechanism for converting mechanical energy from pedal to electrical energy . For running of appliances we need to convert this dc power to ac power by using inverter. Output of the dynamo or generator depends on the speed. .
Graphene Based Luminescence and Optoelectronics
(IUT, EEE, 2016-11-20) Choudhury, Irfan Ahmed; Al Mamun, Fahad
Charge carriers in graphene mimic two-dimensional massless Dirac fermions with linear energy dispersion, resulting in unique optical and electronic properties. They exhibit high mobility and strong interaction with electromagnetic radiation over a broad frequency range. Interband transitions in graphene give rise to pronounced optical absorption in the mid-infrared to visible spectral range. Free-carrier intraband transitions, on the other hand, cause low frequency absorption, which varies significantly with charge density and results in strong light extinction at high carrier density. These properties together suggest a rich variety of possible optoelectronic applications for graphene. But graphene is a zero bandgap material which hinders the uses of graphene in luminescent application. In this thesis paper, we have addressed this bandgap problem and reviewed some of the important achievements so far in introducing bandgap in graphene.we have also investigated the optoelectronic properties of graphene and reviewed some of the significant applications.Later, we have discussed about graphene quantum dot and their applications in multicolor light emitting applications and in solar cells
Low Loss Porous Core Photonic Crystal Fiber for Long Distance THz Radiation
(IUT, EEE, 2016-11-20) Reza, KM Samaun; Rahman, S.M. Shafi-Ur; Hossain, Riasat Tanjim
Fiber optic systems are important telecommunication infrastructure for world-wide broadband networks. Wide bandwidth signal transmission with low delay is a key requirement in present day applications. Optical fibers provide enormous and unsurpassed transmission bandwidth with negligible latency, and are now the transmission medium of choice for long distance and high data rate transmission in telecommunication networks. Our main objective is to design an optical waveguide which will be able to transmit terahertz signal into longer distances. In this thesis, two Porous-Core Photonic Crystal Fiber with ultralow Effective Material Loss (EML), high core power fraction and ultra-flattened dispersion is proposed for terahertz (THz) wave propagation. All the simulations are performed with Finite Element Modeling (FEM) package, COMSOL v4.3b. The design can be fabricated using stack and drilling method. This thesis examines effective material loss, core power fraction, modal effective area, dispersion, birefringence, confinement loss of the proposed waveguides. Characteristics analysis is done by varying the geometrical parameters. The results of the analysis are further compared with those of previous reported contributions
Metal Nanoparticle Induced Enhancement of Light Absorption in Thin-film PV Cells
(IUT, EEE, 2016-11-20) Ohib, Riyasat; Yeasar, Samin; Ali, Sayem
The aim of this thesis is to investigate the utilization of plasmonic metal nanostructures for efficiency enhancement of thin-film solar cells. This efficiency enhancement strategy exploits the strong near-field enhancement and highly efficient light scattering that originates from localized surface plasmon resonances (LSPRs) excited in metal nanostructures and leads to an increased absorption in the solar cell active layer. In the first part of this thesis, the near-field enhancement is explained with rigorous theoretical details and how the electromagnetic characteristics alters significantly if a nanoparticle interacts with an incoming field. We have simulated in COMSOL the incoming electric and magnetic field pattern for a single dielectric particle. We have also shown the far-field radiation pattern and scattering characteristics. We have also demonstrated the enhanced resonant electric field (Hot Spot) and wavelength for peak electric field between 2 nanoparticles in close proximity. Later on, we have constructed models where we chose different metal nanoparticles (Al, Cu, Ag, Au) covered by thin-film absorber layer (GaAs, CdTe). We have measured the enhanced magnitude of absorption and scattering in presence of each of these nanoparticles which boosts the efficiency of an otherwise lacking thin-film absorber without the implementation of nanoparticles. Also we have demonstrated how varying the size of the nanoparticles impacted on the absorption enhancement. We have also delved into the recently emerging organic solar cell technology, very particularly, the Perovskite solar cell. Introducing nanoparticles into the Perovskite absorber layer results in higher absorption and scattering. We have measured the absorption enhancement in presence of different noble metal NPs (Al, Cu, Ag, Au). Also we have demonstrated the effect of the radius of the each of the metal NPs into absorption enhancement. Due to this absorption enhancement, the plasmonic nanostructured cell exhibits an enhanced power conversion efficiency compared to an optimized, high performance organic solar cell
Nuclear Power Need & Key Issues:
(IUT, EEE, 2016-11-20) Hoque, A.K.M. Ashraful; Mahmud, Rafid Hasan; Noor, Rashed-Uz-Zaman
Online Live Street watch application supported by LTE-A & Automated Switching to Selected UE Mode of Operation for Restricted Area in LTE
(IUT, EEE, 2016-11-20) Hasan, Mahmudul; Samad, Mustakimus; Abdussami, Rafiul
The online applications for street information have gained much popularity and wide use recently. The growing data rate of cellular services at affordable cost is supporting such applications. The Long Term Evolution (LTE) and its later version, LTE-Advanced (LTE-A) are now the most promising technologies for the cellular services. The street information, presently available online for general users, is either limited or not presented in enough user-friendly way. In this paper, we discuss a user-friendly approach for an application that provides online live view of the streets disseminating a lot of information. We analyze the potential usefulness of this application. We consider the use of LTE-A to upload video data from traffic cameras for the application. We propose a method to configure less frequent transmission of cell measurement reports in LTE-A in order to save wireless resources and power during this video data upload.
Optical fiber for terahertz wave
(IUT, EEE, 2016-11-20) Rahman, Jamilur; Rafi, Md. Abdur; Uddin, Md. Ashfaq
Terahertz radiation occupies a middle ground between microwaves and infrared light waves known as the terahertz gap, where technology for its generation and manipulation is in its infancy. The frequency band of 0.1-10 THz, known as THz band has brought potential applications in many important fields. For wave propagation THz systems use free space as medium. But in free space waves face many difficulties which is very big issue for wave propagation. So we have to use guided transmission instead of unguided transmission. In the mean time many guided transmission line has many kinds of deprivation such as effective material loss, confinement loss, bending loss, dispersion loss, power fraction issue etc. So we had decided to make a porous core fiber which has less losses than other PCF. Mainly we have been inspired from previous papers in which these losses was too much high for THz wave guidance. Then we have designed rotate hexagonal core and decagonal cladding with 8% PML of total fiber radius. This design gives a lower effective material loss and comparatively higher mode power propagation as well as a flattened dispersion gained over the frequency range 0.95-1.25 THz.