European Journal of Scientific Research
 Volume 100 No 2
Estimation of Channel Response and Frequency Offset in MIMO-OFDM Systems
Navid Daryasafar, Saeid Hamidi, Mohammad naser Moghaddasi and Nooshin Rabiee
This paper presents a channel estimation scheme for multiple-input multiple-output with orthogonal frequency-division multiplexing (MIMO-OFDM) in frequency selective fading channels. According to this, with investigating the channel estimation method, we will design optimum training courses for these systems and will introduce related comparative methods based on LMS and RLS algorithms. We have compared the performances of channel estimation algorithm by measuring bit error rate vs. SNR with QPSK modulation scheme. LS method offers accurate estimation of channel. In this paper LS method was used for initial channel estimation. For improving accuracy of channel estimation, LMS algorithm was added to receiver which includes a feedback of output and improves the BER performance of system. On the other hand, NLMS/RLS CE algorithm requires knowledge of the received signal only. Simulation results demonstrated that the RLS CE method has better performances compared NLMS CE method for MIMO OFDM systems. Therefore, in order to combat the more channel dynamics, the RLS CE algorithm is better to use for MIMO OFDM systems.
Keywords: Multi-Input Multi-Output systems, Channel Estimation, Synchronization, LMS algorithm, Recursive least squares (RLS) algorithm.
Comparative Analysis of Square and Circular Air Holes in Hexagonal Photonic Crystal Fiber Structure
S. Revathi, A. Amir, Abhijith Chandran and Srinivasa Rao Inbathini
In this paper comparison is made for the optical properties of five ring hexagonal structure photonic crystal fibers(H-PCFs) comprising square air holes and circular air holes. Optical properties which are used for comparison are chromatic dispersion, confinement loss, effective mode area and nonlinearity. For both the proposed PCF structure first ring of air holes are made smaller with respect to other four of the air hole rings. Proposed structures are simulated by using Comsol multiphysics. Method used for simulation is finite element method (FEM).Perfectly matched layers(PMLs) are used to satisfy boundary conditions. Negative dispersion and high nonlinearity values are obtained for the proposed hexagonal structured PCFs having circular and square air holes. Confinement loss is small for the both structures, whereas nonlinearity is high. Large negative dispersion is obtained for H-PCFs having square air holes with structural parameter i.e d=0.576µm and pitch length of 0.96µm. Maximum nonlinearity obtained is 67.9 w-1km-1 for square air hole structure at 1550nm. Since the proposed structure offers negative dispersion and high nonlinearity this structure can be suitable for dispersion compensation fibres.
Keywords: Confinement loss, Dispersion, Nonlinearity, Photonic crystal fibers(PCF)
Strategic Change in Knowledge Management and e-Learning: Enhancing Workplace Learning
Ali Mahdi Owayid, Khalid Alrawi and Khaled Shaalan
E-learning is an emerging field in the intersection of education learning, and business, referring to delivered information and education services or improved via Internet services and related technologies. The paper is an attempt to show how knowledge management (KM) and E-learning (EL) specifically can be of prominent support in the workplace. Aligning firm as a whole to a continually changing environment as far as learning and innovation are concerned is a challenge. The paper posits that KM consists of enablers such as Information systems infrastructure, Team working, Employees involvement, Top management leadership and commitment, and Employee empowerment that are critical to the success of a knowledge-based organization. The presented model in this paper integrates Knowledge management and e-learning into adaptable framework that offers integrated support as well as effect on various Medias involved in the education systems. The model is a suggestion to improve teaching and learning process and how KM adds a successful help for educational consumers in selecting and evaluating e-learning media. The model is based on an analysis of KM and e-learning literature and the information search process.
Keywords: Knowledge Management, E-learning, Knowledge Management Enablers, Managers Commitments, Decision Making
Wavelet Applications in Power System Protection and Fault Analysis
Abdulhamid A. Abohagar and M.W. Mustafa
In the present era, stability and reliability have become the most important issue of the power system utilities. To run the power with high level of stability and reliability, transmission lines should be completely protected. In this study, wavelet transform WT has presented to detect and classify transmission line faults, wavelets have adopted here because its ability of dealing with such transient disturbances. The algorithm is based on discrete wavelet transform DWT which is used for extracting the three phase current signal that is under single line to ground fault. Then, the proper selection of mother wavelet Daubechies4 has played the significant role of getting the useful information from fault condition. Finally, the classification process is based on the calculating absolute sum of the signal detail at level 2 over one cycle window. Power System Computer-Aided Design /Electromagnetic Transients with DC (PSCAD/EMTDC), is used to generate the three phase current signal from IEEE 6-Bus Transmission System. Simulation results reveal that the proposed algorithm has granted perfect detection and classification of faulted phase and healthy one.
Keywords: Wavelet transforms, transmission lines, power system faults, power system protection, power system stability.
Ontology based Association Rule Mining Algorithms for Intelligent Decision Making
RM. Vidhyavathy, E. Ramaraj and N. Venkatesan
Learning, like intelligence, covers such a broad range of processes that it is difficult to define precisely. With respect to machines, it can be broadly said that a machine learns whenever it changes its structure, program, or data (based on its inputs or in response to external information) in such a manner that it is expected future performance improves. The objective of this work is to build an association rules in healthcare framework that is discovered by converging the semantic web and apriori based techniques. This healthcare framework would empower the patient and physician both for taking better decision for managing health. Healthcare institutions need to target the patients with proper portfolios of services. There is a wealth of data available within the healthcare systems but they lack effective analysis tools to discover hidden relationships and trends in data. By applying web mining techniques on ontology based structure of web, useful patterns and knowledge can be discovered for making intelligent decisions for the care of individuals. This paper proposes a novel ontology and association rules based algorithm. The algorithm firstly introduces the domain ontology and hash technology to improve the operation of emerging frequent item sets and generating association rules, then uses a hash table to store the domain ontology, and the algorithm transforms the operation of the database into memory tree base. The results show the advantages of the rule mining algorithms.
Keywords: Ontology, Data Mining, Association Rule, Semantic web, Web mining, Healthcare
Metamaterial Split Ring Resonator Loaded Printed Circular Patch Antenna
Falguni Raval and Yogeshwarprasad Kosta
This paper proposes microstrip circular patch antenna where metamaterial properties are applied at the ground plane. The work mainly includes metamaterial as defected ground plane. The paper also analyzes the performance of microstrip patch antenna with and without metamaterial spilt ring resonator structure at 2.65 GHz. Effective permeability of spilt ring resonators is calculated from S parameters. The antennas are fabricated on FR4 substrate and tested experimentally using a network analyzer in Sumeru Microwave Communication Lab. Antenna parameters such as return loss, radiation pattern and gain are observed. Good agreement is reported between the simulated and measured reflection coefficient results. The main purpose of this paper is to check the effect of metamaterial on patch antenna so that it can be used for multi-frequency operation.
Keywords: Defected Ground Plane/Structure (DGP/DGS), Open Slot Split Ring Resonator (OSSRR), Circular Patch Antenna, Microstrip, Metamaterial, Split Ring Resonator (SRR), High Frequency Structure Simulator (HFSS)
Layout Optimization for the Process Industry
S. Godwin Barnabas, S. Anantharam, N. Balaganesh, K. Vijaya Kumar and M. Jayapandi
In this paper a small modification in the existing layout of the production plant of a company has been made so , that it will reduce processing time and ultimately results in better production the same work dynamic programming has been used to maximize product varied for the specified process route has been done.
Keywords: Existing layout, production rate, processing time, dynamic programming, product variety, etc.
An Assessment of GARCH Models in Forecasting Volatility; Evidence from Tehran Stock Exchange
Javad Kamarei and Younes Nademi
In this paper, we have compared different GARCH models with both Gaussian and fat-tailed conditional distribution for residuals in terms of their ability to describe and forecast volatility. The best model based on MSE criteria is GARCH with normal distribution, second model is GARCH with t distribution and third model is EGARCH (1,1) with normal distribution.
Keywords: GARCH, Volatility, Forecast, Tehran Stock Exchange
Optimizing E-Learning in Nigerian Universities for Sustainable Development
Njoku, Collins Chibuzo and Ilechukwu, Leonard Chidi
A dialectical nexus exists between education and development. With Nigeria’s paradoxical ashamedly poverty and underdevelopment profile amidst abundant potential wealth, effective educational service delivery especially at the higher education level which is critical to human and national development is imperative. Thus, education in the 21st century global knowledge economy requires a paradigm shift in the delivery system to match the emergent new knowledge, attitudes, skills and technologies. Since curriculum is a vehicle for attainment of educational goals and methods of delivery are a component of the curriculum, there is need for employment of effective delivery systems which will produce functional citizens locally relevant and globally competent. E-learning which means electronic learning is an ICTs – driven new face of education service delivery superior to the traditional brick wall classroom learning. But there are challenges and gaps for an effective e-learning in the universities. This paper, therefore, using a library research method, attempts to demystify all this and articulates twelve nuggets strategies to optimize e-learning in Nigerian universities for Nigeria’s sustainable development and global competitiveness.
Keywords: Education, Development, ICT, E Learning, Optimize, Curriculum
Novel Real Time Queue Estimation Method in Oversaturated Road Networks
Shahriar Afandizadeh Zargari and Nazli Dehghani
In case of oversaturated road networks, the issue of traffic control, Queue management and traffic management are severely interrelated with each other. A great idea for controlling oversaturated road networks developed based on the concepts of queue management. This paper presents a novel queue estimation method considering platoons of vehicles in queue estimating procedure. Proposed model is validated using real field data gathering by SCATS and queue detector installed in an arterial in Tehran city. Two more effective parameters related to driver's behavior are the first driver's reaction to green light; tr, and difference between movements start up of two adjacent vehicles in queue; ts. Therefore, present study initially tries to calculate both parameters using statistical analyzes in such a way that related model can be executed based on these parameters. The method has been simulated via VISSIM microscopic simulator and VISSIM COM interface. The result of improved queue estimation model shows better estimation of queue length in oversaturated arterials in comparison with previous models.
Keywords: Traffic control, oversaturated road networks, Queue estimation, calibration
A Risk Estimation of Anemia Disease among Pneumonia Patients using Logistic Regression Model
Wan Muhamad Amir W Ahmad, Nurfadhlina Abdul Halim and Nor Azlida Aleng
This paper is focusing on identifying the factors that cause anemia disease in pneumonia patients using Logistic Regression Model (LRM). Pneumonia is an infection in the lung inflammation that involves the small air spaces alveoli. Anemia disease is a phenomenon where a person decreases in number of red blood cells than the normal quantity of haemoglobin in the blood. Factors consider in this study are age, gender, ethnicity, hypertension, asthma and diabetes mellitus. Result shows that the most significant factors which contribute to anemia disease among pneumonia patients are race, gender, and hypertension.
Keywords: Anemia disease, pneumonia, logistic regression model
On the Folding of Buchdahi Space
A. E. El-Ahmady and N.Al-Hazmi
Our aim in the present paper is to introduce and study new connection between retractions, foldings and deformation retracts of hyperspheres in Buchdahi space and hyperspheres in Minkowski space. Types of minimal retractions of Buchdahi space and Minkowski space are presented. The limit of the folding will be obtained. The connection between the minimal geodesics of Buchdahi space and Minkowski space is achieved.
Keywords: Retraction, Folding, Buchdahi space, Minkowski space.
Mathematics Subject Classification Codes:51H10,57N10.+
Experimental Investigation of Neem De-Oiled Cake Powder Diesel Blend in Diesel Engine
A.A. Arivalagar and S. Arul
In this study, diesel blended with powdered de-oiled cake of Neem, at different proportions by weight is used in a single cylinder diesel engine. After mixing, it is stirred constantly to ensure the maximum dissolution of oxygen rich residual fatty substances left available in de-oiled cakes in Diesel. The fuel is filtered and tested. The physical and fuel properties were determined and found to be within the limits prescribed for biodiesel. The quality of blends was tested through gas chromatography. It is observed that there is a reduction in HC, CO and smoke density with marginal increase in NOx emission. 10% neem de-oiled cake diesel blend gives better brake thermal efficiency than neat diesel and other blends.
Keywords: Neem de-oiled cake powder, blended fuel, performance, emission characteristics, Gas chromatography.
Mobility and Density Enhancement version of AODV
S. Deepa and G.M. Kadhar Nawaz
An Mobile ad hoc network is formed by collection of wireless mobile nodes creating a short-term Network without using any centralized support. The nodes are connected to each other using peer to peer Wireless Communication. Many Routing protocols have been developed for performing this task. Mobility and node density are the two major factors which has much influence on the performance of any routing protocol of mobile ad hoc network. In this Research Work, We investigate the performance evaluation of routing protocols and propose schemes to enhance the performance. we proposed a new method to improve the performance of AODV by reducing overhead by adopting a route message propagation mechanism. According to the new scheme, a node will be selected to forward a routing request message if and only if a condition based on its mobility (speed) and number of neighbors is satisfied. If the routing request is allowed to propagate through a node then there will be at least a possible path which includes that node in its path list. At the end of the route resolving process, the destination will have a possible path through that node. If the routing request is disallowed to propagate through a node then there will not be a possible path through a node to the destination in the end of the route resolving process. We implemented the idea on network simulator (ns2) and measured the improvement in performance.
Keywords: Mobile Ad hoc Network, Routing Overhead, Route Discovery , Mobility Aware Routing, Routing Protocols, DSDV, DSR, AODV, MADA-AODV.
Investigation on the Influence of Fluctuation in Thrust Force and Vibration in Drilling GFRP Composites by Recurrence Quantification Analysis
Jessy.K, Satish Kumar.S, Dinakaran.D and Seshagiri Rao
The advantage of composite materials over conventional materials is that they possess high specific strength, stiffness and fatigue characteristics, which enable structural design to be more versatile. Owing to the inhomogeneous and anisotropy nature of composite materials, their machining behavior differs in many aspects from metal machining. Fluctuations in thrust force are an unfavorable phenomenon during drilling GFRP which accelerates tool wear and delamination of the workpiece, hence it is necessary to study fluctuations in thrust force for the selection of proper drilling conditions. This work presents a new approach to find the fluctuations in thrust force and its effects on machining vibration. This study is useful for selecting suitable drilling conditions for better tool life and lesser damage factor of workpiece during drilling GFRP. The fluctuations in vibration signal were analyzed using recurrence quantification analysis. Speed range of 750rpm and feed range of 5mm/min offer lesser delamination with improved tool life by 85%.
Keywords: Drilling, GFRP, Thrust force, Delamination, Vibration and Recurrence rate.