European Journal of Scientific Research
Volume 102 No 2
Fuzzy Optimized PWM Controller for Harmonics and Commutation Torque Ripple Minimization in BLDC Motor Drive
A. Albert Rajan and S. Vasantharathna
The Brushless DC motor (BLDC) drive is extensively used in many industrial and domestic appliances due to its higher efficiency, lower maintenance, high reliability and high torque to weight ratio. This motor drive requires improvement in minimizing the harmonics present in the stator voltage and current. Also this motor suffers with high degree of torque ripple. This paper focuses on reconfigurable controller using fuzzy logic technique for variable frequency and variable duty ratio Pulse Width Modulation (PWM) operation to minimize the harmonics and the commutation torque ripple. The frequency and the Duty ratio are dynamically adjusted by the fuzzy controller for steady speed of the motor. This technique is implemented using Virtex II Pro Field Programmable Gate Array (FPGA). The experimental results confirm the effectiveness of this technique in minimizing harmonics and torque ripple.
Keywords: Brushless DC motor, Field Programmable Gate Arrays, Fuzzy Logic Controller, Pulse Width Modulation. Total Harmonic Distortion
Examining the Impact of Board of Directors and Ownership Structure on Bank Performance
Ali Hedayati, Mehran Matinfard and Mohammad Abed
The purpose of this study is to survey the relationship between corporate governance mechanisms and private banks performance during the years 2008-20012. The dependent variable of this study is financial performance that is a function of CAMEL ratios(capital adequacy, asset quality, management efficiency, earning and liquidity). The independent variables are included the size of the board, the proportion of independent directors, the proportion of ownership of Institutional shareholders and the proportion of ownership of major shareholders. The model for testing the hypothesis is multiple regression. The results of this study shows that all independent variables have impact on, at least, one of the dependent variables, so we can conclude that there are meaningful relationships between financial performance of banks and corporate governance mechanisms, but, the degree of this impact is different between independent variables, the proportion of independent directors has a meaningful impact on capital adequacy, asset quality ,management efficiency and earning of banks, the proportion of ownership of major shareholders has a meaningful impact on capital adequacy, liquidity and earning, the proportion of ownership of Institutional shareholders has a meaningful impact on capital adequacy and management efficiency, the size of the board has a meaningful impact on earning of banks.
Keywords: Corporate Governance, Non Executive Directors, Ownership structure, Institutional shareholders, Performance, Financial Institutions and Services, Banks; Depository Institutions; Micro Finance Institutions; Mortgages
JEL classification codes:IS G21
Design and Fabrication of Microwave Waveguide Resonator: With Improved Characteristic Response
Amit Patel, Yogeshwarprasad Kosta, Neetirajsinh Chhasatia and Falguni Raval
Designing techniques of resonator using the non-planner model that is most preferable among all present for low cost mass production of microwave and millimeter wave circuits and systems. This paper basically concerned with the improvement characteristics of post coupled designs that have been modeled and it demonstrates the approach to overcome the limitation inherent in hairpin as well as suppression of the harmonic which is prominent in the micro strip coupled filter and resonator topology. This has been achieved using the design concept of finite conductive post coupled obstacles into the perfect impedance match rectangular waveguide. The modified topologies of the post coupled along with the concept of reduced insertion loss and better return loss with improved quality factor has been achieved. Furthermore, presented structures results are sensitive to standard design equations and dimensions of the elements used. The resonator topologies were designed here at the center frequency of 11.2 GHz, with insertion loss -0.06dB and return loss -30.02dB with narrow bandwidth having Q-factor more than 100 and VSWR (Voltage standing wave ratio) =1. 0 which can transform into the bandpass filter having a bandwidth of 900 MHz.
Keywords: Insertion loss, Post coupled waveguide, Q-factor, VSWR (Voltage Standing-Wave Ratio)
Recent Evolutions of Roundabouts: Methodological Issues and Practical Concerns
Orazio Giuffrè, Anna Granà, Roberta Marino and Sergio Marino
The aim of the research is to provide a choice criterion between innovative roundabouts (turbo-roundabouts and flower-roundabouts) and double-lane roundabouts by evaluating convenience in terms of performances, when traffic demand is known. For this purpose, comparisons of operational performances at innovative roundabouts with regard to those at traditional roundabouts were developed. We started from consistent assumptions regarding the arrival process of major streams and used capacity models founded on gap-acceptance theory. Having in mind a bunched exponential headways distribution, we proposed adaptations of the Hagring model for estimating entry capacity at intersections under examination, where movements with only one or two conflicting traffic streams can be observed. Suitability domains (or indifference areas) were obtained using as comparison criterion the control delay since it is related to the level of service quality. Results provide some evidence of convenience or not in choosing a turbo-roundabout or a flower roundabout rather than a double-lane roundabout, both for new installations and for conversion of existing roundabouts.
Keywords: Roundabout, Turbo-roundabout, Flower-roundabout, Capacity, Delay.
An Awareness Assessment of Communicable Diseases Threat in Jazan Region, Kingdom of Saudi Arabia( KSA)
Ibrahim A Bani
Several studies conducted in Saudi Arabia to assess clinical aspects and factors associated with prevalence of communicable diseases, which in turn highlighted the need to increase public awareness disease control at the local community. This cross-sectional community-based study aimed to evaluate the level of awareness of selected common communicable diseases among Abu Arish community members in Saudi Arabia. Self-administrated questionnaires together with focus groups discussion were used as data collection tools. Unlike TB (79.2%) and Hepatitis B and C (78.8%), almost half of the communities (49.5%) were unaware of dengue fever. The rate of awareness was of TB, Hepatitis and Dengue was significantly (P<0.05) influenced by literacy and (to some extent) residence in rural areas. Unlike dengue fever, the majority of the community were aware of TB, and hepatitis B and C
Keywords: Dengue Fever; Hepatitis; Tuberculosis (TB); Jazan.
A New Approach for Calculating the Ratio of Nuclear Level Densities
Ebrahim Rahimi, Aziz Behkami and Ghazaleh Shirdel
Nuclear level density (NLD) is one of the properties of each nucleus with widespread application including astrophysics and nuclear medicine. Since there has been little experimental and theoretical research on the study of nuclei which are far from stability line, studying NLD for these nuclei is of crucial importance. Also, nuclear level density is an important input for nuclear reactions codes, hence studying methods for calculating this quantity is essential. In the current study, a new computational metod was applied for the calculation of ratio of the nuclear level densities with odd-and even parities as a function of excitation energy. Implementation of the computations for 56Fe revealed that, this approach is able to describe nicely the transition from low excitation energies, where only a single parity dominates, to high excitation energies where the probabilities for the two parities are equal. Finally, it was shown that here is a good agreement between the results obtained from our computations with those of obtained from the Shell Model Monte Carlo Method.
Keywords: Nuclear level density, Nuclear reaction codes, Nuclear structure
Fusion Strategies in Multi Biometric System with EER Analysis
M.Mani Roja and Sudhir Sawarkar
Some of the limitations imposed by unimodal biometrics systems can be overcome by integrating multiple biometric modalities. This paper, proposes an approach to improve the performance of a biometric system by integrating different unimodal biometric traits. Three modalities, fingerprint, face and signature are integrated. Three levels of fusion schemes namely feature level, score level and decision level and three different types of normalization such as min-max, z-score and tanH have been investigated in this work. The performance of score level fusion was found to be better than feature level fusion. The proposed system was able to give 100 % recognition rate using score level fusion. In decision level fusion, the use of ‘OR’ logic is proposed for low security applications and ‘AND’ logic is used for high security applications. The system performance was evaluated using receiver operating characteristics and equal error rates.
Keywords: Multi Biometrics; Discrete Cosine Transform; Equal Error Rate.
Design and Implementation of Various Modulation Techniques in OFDM with Software Defined Radio
S.Prabu and E.Logashanmugam
In this paper we implement various modulation and demodulation techniques for orthogonal frequency division multiplexing in FPGA using software defined radio concept. By implementing OFDM with software defined radio is capable of working with all modulation techniques. We have concluded from the experimental results, that the QPSK modulation is having low area and less power. A FPGA implementation of Software defined radio is presented and their resources utilisation can be analysed.
Keywords: Software Defined Radio (SDR), FPGA.
Analysis of Voltage To Current Convert Sense Amplifier for Low Power Sram
R.Varatharajan, M.Sundhararajan, R.Sivakumar and G.Murugaboopathi
A new current-mode sense amplifier is presented. It extensively utilizes the cross coupled inverter for both local and global sensing stages, hence achieving ultra low-power and ultra high-speed properties simultaneously. Its sensing delay and power consumption are almost independent of the bit- and data-line capacitances. The new design outperforms other designs. The analysis is done with the comparison with the existing systems which are alpha latch sense amplifier and Decoupled latch sense amplifier and Sensitivity analysis has proven that the new design offers the best reliability with the smallest standard deviation. SRAM cells have been used to validate the design, in comparison with other circuit topologies. The new design is designed using tanner. The technology used is 0.18µm. Current mode sense amplifier does not depend upon the bit line and data line capacitance. These attributes of the proposed circuit make it a wise choice for contemporary high-complexity systems where reliability and power consumption are of major concerns. Charge Transfer Sense Amplifier (CTSA) has to be proposed and it shows an improvement for consumes less power than the current mode sense amplifier.
Keywords: Current mode and sense amplifier, low power, low voltage SRAM
Phase Transformation Modeling of AISI 4140 Steel Rods after Hot Rolling and during Quenching
Mahmoud Hajisafari and Amirhossein Meysami
Direct quenching (DQ) process is an appropriate method in steels heat treatment field after hot rolling. During direct quenching of steel components, obtaining the desired distribution of microstructure would satisfy production goals and reliable service performance. In this study, a Finite Volume Model (FVM) based model has been developed to describe diffusional and diffusionless transformation in AISI 4140 steel rods during direct quenching. In non-isothermal quenching process, subdivision of the cooling curve into various small isothermal steps was introduced with the help of various time–temperature–transformation (TTT) diagrams of AISI 4140. In addition, Scheil’s additive rule and Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation were also solved. On the other hand, Koistinen and Marburger’s equation was used to model the diffusionless transformation. This model could predict microstructure evolution and volume fraction of each phase during process, so that it permits the progress prediction of ferrite, pearlite, bainite, martensite and retained austenite transformation simultaneously. To verify the model results, several experiments have been performed on a physical model. After direct quenching of AISI 4140 rods with radius 55 mm, volume fraction of retained austenite and other phases including ferrite, bainite and martensite have been measured through magnetization and XRD methods. There was a good agreement between numerical and experimental results.
Keywords: Hot Rolling, Direct quenching, AISI 4140, FVM modeling, Phase transformation
Influence of Family Upbringing, Age and Gender on Aggressive- Crime Behaviour among Secondary School Students
Mary Basil Nwoke
The study investigated influence of family upbringing, age and gender on aggressive - crime behaviour among students. 512 students freely participated in the study. Twelve students sampled from a co- educational secondary school in Enugu, six (JSS111), (13-15) years, with a mean age of 14years; six (SS111), (16-18) years, with a mean age of 17 years, on equal gender provided preliminary information. Five hundred students randomly sampled from five secondary schools in Abuja. Hundred participants from each school. Three co-educational secondary schools, one all Girls and one all Boys were involved. 250 (JSS 111), 125 males and 125 females, age (13-15) years, with a mean age of 14 years, 250 (SS111), 125 males and 125 females, age (16-18) years, with a mean age of 17 years. An instrument called Family Upbringing Scale (FUBS) was used for the study. Results showed significant family upbringing and age as predictors of aggressive-crime behaviour among students F (2,489) = 18.7p<.0001; F(2,489)=10.4p<.0001. Family x age interaction was significant, F(2,489)=6.74p< .002; family x gender interaction was significant, F(2,489)= 5.51p< .002. Family x age x gender interaction was significant F( 2, 489) = 6.52 p< .002. Scheffe test of comparison showed that students living with step-parent families are more inclined to aggressive-crime.
Keywords: Aggressive-behaviours, crime, family upbringing, students.
Modeling and Simulation of Stable Walking on Slope for a Planar 3-Links Biped Robot
S. MohammadReza S. Noorani and Ahmad Ghanbari
In this paper a coherent framework for generation and stabilization of the walking gait on slope for a planar three links biped robot with point feet will be presented. The followed method is based on orbital stabilization of the hybrid zero dynamics via Poincare return map analysis. Indeed, since the dimension of the zero dynamics is considerably less than the dimension of the model itself, the task to be achieved by the robot is explicitly encoded into a lower-dimensional system. Successfulness of the method is verified by simulation results.
Keywords: Planar Biped Robot, Walking Gait, Poincare Return Map.
Survey of Dimensions that Influence the Success of Knowledge Management in Islamic Azad University of Karaj
Many organizations have focused their efforts on how could manage the knowledge in the organizations. There are many benefits of Knowledge Management (KM) for organizations, of which can be noted to improve the quality of work, having updated information, increasing ability to respond to the needs of other organizations, and ability to change and quick versatility. Since, KM acts as a competitive advantage, element of growth, and development of current organizations especially in educational organizations are specified the necessity to address this issue and efforts to make it more effective to achieve the organization goals. This study examines the KM system and its affective dimensions on Islamic Azad University of karaj. The study statistical sample consisted of 244 executive employees, directors and employed professors in this educational institution. The research hypotheses based on the four dimensions of KM system have developed that are including “culture & structure”, “technology”, “reach & transform” and “use & keep” of available knowledge in the organization. The Model of KM system used in this study has studied by Structural Equation Modeling (SEM), and the results have indicated a good fit of the research model. In addition, results from the survey of research hypotheses were showed that among the dimensions of KM, “technology”, and “reach & transform” of knowledge has been had the more rate than the other variables to predict KM variable.
Keywords: Knowledge Management (KM), Knowledge, Knowledge Management Dimensions
Impact of CSR on Brand Loyalty: Mediating Role of Functional Image
Hafiz Imran Akram, Hafiz Ihsan-ur-Rehman, Muhammad Ashar and Bakhtawar Javed
In recent decades, the benefits of corporate social responsibility gaining much attention of the global executives, including positive brand attitude, combating negative publicity trust, and customer loyalty. CSR as an important source of competitive advantage can build positive brand image and attitude of consumers towards brands. In this study, we are interested in consumers’ perceptions of CSR. We examine the indirect relationship between one of the dimension of CSR and brand loyalty by introducing mediator, including functional image & based on data from consumers in the Food industry of Pakistan in particular for global brand such as McDonalds. To analyze the factors that influence Brand Loyalty, 200 questionnaires were distributed to the customers of McDonalds. One hundred and seventy complete questionnaires were received with the frequency of 85%. This study offers a course of action to the Managers that how to improve their profit and retained their customers by using such an effective strategic marketing tool; Corporate Social Responsibility. This study finds out that Corporate Ethical Responsibility have strong influence on Brand loyalty as well as there is evidence of mediation effect of Functional Image.
Keywords: Corporate Social Responsibility, Functional Image & Brand Loyalty.
Semiotic Analysis of Street Photography of Daily Life in Tehran in the 40s and 50s of Hijri Shamsi in Iran before the Islamic Revolution
Azadeh Farmahini Farahani, Nader Amiri, Mehdi Akhavian
In this paper, the semiotic and critical analysis of Street Photography of everyday life of the middle class in the city of Tehran (40s and 50s of Hijri Shamsi) before the Islamic Revolution in Iran is addressed using theoretical-methodological issues, connotations (John Fiske) and mythology (Roland Barthes). since in documentary photography, society's attitudes has been augmented with the origin belonging to the subcultures and inner layers of the society and street photography as the body of documentary genres makes scenes of people’s everyday life its main subject and thereby a clearer understanding of social, economic and cultural situation; distinct and common pathways of images of everyday life in middle-class; culture and art of the society and also way of representation of evolution in the daily lives in generation objects changes, components and the composition of elements in the studied photographs, is obtained. Results show the relation between everyday life style of people with composition of elements and components of photographs from a semiotic perspective based on aspects of cultural and ideological views of the society. Also visual elements in iconic semiotics represent the hidden meaning of myth in the cultural and ideological systems of the society represented by cultural and artistic aspects of the society and the existing visual signs in the studied photographs change with respect to culture and ideology of the society.
Keywords: Street Photography, Semiotics, The 40-50s of Hijri Shamsi, Tehran