42 research outputs found
An Interactive Dialogue for the Creation, Maintenance and Querying of a Data Base Representative of the Anatomy of an Administrative System
Get PDFTitle: An Interactive Dialogue for the Creation, Maintenance and Querying of a Data Base Representative of the Anatomy of an Administrative System, Author: Pratima Mathur, Location: ThodeThe logical structure of a database is given, and is
representative of the anatomy of an administrative system,
and of the personnel organization by which it is operated.
This project will adopt an appropriate host computer,
terminal, and physical representation of the database, for
the main purpose of developing a user-terminal dialogue by
which the database can be created and maintained. The
dialogue should be as easy and flexible to use by an audit
analyst as is possible, while at the same time imposing a
systematic and disciplined approach to the task.ThesisMaster of Science (MS
Optimized OFDM Model Using CMA Channel Equalization for BER Evaluation
Get PDFOrthogonal Frequency Division Multiplexing (OFDM) is a type of Multicarrier Modulation (MCM) technique in which entire bandwidth is divided into large number of small sub-carriers and each subcarrier is transmitted parallel to achieve higher data rates. It has various applications like Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB) and wireless LAN.OFDM technique is widely used in wireless communication system because of its very high data rate. The performance of FFT based OFDM system using Linear and cyclic channel coding and Constant Modulus Algorithm (CMA) equalizer is simulated using simulink model. The BER saving using the optimized proposed model with both linear and cyclic channel coding along with CMA equalizer is evaluated. The proposed work using cyclic channel coding with QPSK/QAM modulation and CMA as channel equalization under AWGN channel results in 52.6% and 96.3% BER reduction as compared to conventional OFDM model without channel coding, channel equalization and channel fading. So, CMA equalizer is used to enhance the performance of OFDM system
OFDM System Performance Evaluation under Different Fading Channels and Channel Coding using Matlab Simulink
No full textOrthogonal Frequency Division Multiplexing (OFDM) is a form of Multicarrier Modulation (MCM) technique in which larger bandwidth is divided into parallel narrow bands each of which is modulated by different subcarriers. All the subcarriers are orthogonal to each other and hence it reduces the interference among various subcarriers. OFDM technique is an efficient modulation technique used in certain wired and wireless application. During transmission, the transmitted signal can travel from transmitter to receiver over multiple reflective paths in case of wireless communication system which results to multipath fading and produces variation in amplitude, phase and angle of the received signal. The signal which is transmitted from BTS (base transceiver station) may undergo multiple reflections from the buildings nearby, before reaching the mobile station. This paper discusses the performance of OFDM system using various fading channels and channel coding. The parameter which is known as Bit error rate (BER) is calculated for different fading channels (AWGN, Rayleigh and Rician) for different digital modulation (BPSK, QPSK and QAM) and Channel coding(linear/ Cyclic coding).The tool which is used to evaluate the BER parameter is Matlab Simulink
OFDM PAPR Reduction Using Recurring SLM with Cyclic and Linear Block Codes Schemes
No full textOrthogonal Frequency division multiplexing is a type of multicarrier modulation technique which is used in various wireless & telecommunication standards. In OFDM, higher data rate is split into several narrowband data stream that is transmitted simultaneously over a number of subcarriers. One major disadvantage of using OFDM is high Peak to Average power ratio. This paper presents the simulation result which compares the PAPR using SLM with Cyclic & Linear block codes. The simulation study verifies that the PAPR reduction by proposed method is better than the existing technique (SLM)
Comparison of various channel equalization techniques in OFDM system using different digital modulations
Get PDFThe nature of future wireless applications requires high data rates and for this OFDM technique is used. OFDM stands for orthogonal frequency division multiplexing and is a type of multi-carrier transmission where all the subcarriers are orthogonal to each other. At high data rates, the channel distortion to the data is very important and it is somewhat impossible to recover the transmitted data with a simple receiver. So a complex receiver structure is needed which uses computationally expensive equalization and channel estimation algorithms to estimate the channel. These estimations can be used within the received data to recover the originally transmitted data. OFDM can simplify the equalization problem by changing the frequency-selective channel into a flat channel. The radio channels in mobile radio systems are usually multipath fading channels that results in intersymbol interference (ISI) in the received signal. To remove ISI from the signal, many kind of equalizers can be used. The need for equalizers arises from the fact that the channel has amplitude and phase dispersion which results in the interference of the transmitted signals with one another which is known as ISI .So, to solve this problem equalizers are designed. Equalizer is intend to work in such a way that Bit Error Rate (BER) should be low and Signal-to-Noise Ratio (SNR) should be high. An equalizer within a receiver compensates for the average range of expected channel amplitude and delay characteristics. This paper deals with the various equalization techniques (LMS, RLS and CMA) used for OFDM system .A comparative analysis of different equalization technique in terms of BER is done using MATLAB Simulink
OFDM PAPR Reduction Using Recurring SLM with Cyclic and Linear Block Codes Schemes
Get PDFOrthogonal Frequency division multiplexing is a type of multicarrier modulation technique which is used in various wireless & telecommunication standards. In OFDM, higher data rate is split into several narrowband data stream that is transmitted simultaneously over a number of subcarriers. One major disadvantage of using OFDM is high Peak to Average power ratio. This paper presents the simulation result which compares the PAPR using SLM with Cyclic & Linear block codes. The simulation study verifies that the PAPR reduction by proposed method is better than the existing technique (SLM)
Comparison of OFDM System in terms of BER using Different Transform and Channel Coding
Get PDFOrthogonal frequency division multiplexing is a type of multicarrier modulation technique which is used in wireless communication. OFDM can be used in various wireless and wired application such Digital audio broadcasting, digital video broadcasting & wireless LAN. The Performance of OFDM system depends on various parameters such as using different transform, different modulation and by putting various channel coding. In this paper OFDM system is modeled by using different transform (DWT/FFT), different modulation (BPSK, QPSK, QAM) and different channel coding (Linear / Cyclic block codes) for AWGN channel. The performance parameter is calculated as Bit error rate (BER) for various transform/modulation/channel coding based OFDM systems. MATLAB Simulink tool is used to calculate the bit error rate (BER)
Exploring the disempowering cultures in prospective science learning: nurturing transformative learning
No full textAs STEAM scholars (authors) and a science teacher educator (the first author), we recognize that conventional teacher-centric prospective science learning cultures require improvement and transformation for authentic, inclusive, and meaningful science learning. In this regard, the driving question of this article is: How has Pratima experienced the disempowering cultures in prospective science learning for nurturing transformative learning? As an autoethnographer, she viewed her prospective science learning-related narrative through a transformative lens to address the spirit of our research question and methodology. She generated three key themes: (i) teacher-student communication as a one-way delivery mechanism, (ii) conceptualizing science as facts and figures, and (iii) prospective science teaching as a cookbook-dominated cultural reproduction through narrative analysis and interpretations. Likewise, she offers to deconstruct these disempowering cultures through enriching and empowering cultures like intercommunication between teachers and students, reconceptualizing science as an everyday phenomenon, and engaging in open-book science teaching-learning. Such science cultures contribute to developing prospective science teachers as change agents
