Partial Face Recognition

-- K Rama Linga Reddy, G R Babu and Lal Kishore

Even though numerous techniques for face recognition have been explored over the years, most research has primarily focused on identification from full frontal/profile facial images. This paper conducts the first systemic study to assess the performance when using partial faces for identification. In this study, two partial face recognition approaches have been proposed. In the first method, artificial neural network is used as the classifier for multi-scaled face components such as eyes, nose and mouth. While in the second method, eigen features/linear discrimination features of face components are used as inputs for artificial neural network. In both methods, it is found that with partial face (face components), the percentage of recognition drops only slightly, compared to the full face recognition, and that eyes play a significant role in recognition. Experiments are conducted on ORL and FERET databases.

© 2010 IUP. All Rights Reserved.

An NN-Based Three-Phase Three-Wired Hybrid Active Power Filter Under Non-Ideal Mains Voltages

-- Satya Prakash Dubey and Anurag Singh Tomer

A Neural Network (NN)-based control scheme for DC link voltage regulation and harmonic filtering using parallel Hybrid Active Power Filter (HAPF) has been presented. The neural network extracts fundamental frequency component from non-sinusoidal and unbalanced currents and then generates the required reference signals. It has been shown that the proposed neural controller is simple, fast and accurate. Simulation results obtained under unbalanced and non-sinusoidal source and load have been presented to demonstrate the effectiveness of the proposed controller.

© 2010 IUP. All Rights Reserved.

VoIP Signal Processing in Digital Domain

-- Hardeep Singh Dalhio, M Mian and Jasvir Singh

The transmission of Voice over Internet Protocol (VoIP) requires signal processing for reliable and efficient performance over the computer and the communication platform. Speech quality, as perceived by the users of VoIP telephony, is critically important to update the service. Signal quality is degraded by network layer problems, ,including delay, jitter and packet loss. This paper presents a simulation model for VoIP and a simulative analysis of VoIP. The digital filtering algorithm is implemented on degraded VoIP speech signal.

© 2010 IUP. All Rights Reserved

A Comparison of Rayleigh and Rician Fading Channels Under Frequency-Selective Fading

-- P Narasimha Murthy and R V S Satyanarayana

Multipath fading and motion induced fading are the two most severe performance limiting phenomena in wireless environments. In a wireless communication channel, there can be more than one path in which the signal can travel between the transmitter and receiver. The presence of multipath components may be due to atmospheric reflection or refraction, or due to reflections from other Interfering Objects (IOs). In a more general case of multipath propagation, which involves a radio channel with several IOs and a moving receiver, a deterministic description of the radio channel is not efficient, and we have to resort to statistical methods. The statistical description of the radio channels is essential for wireless communication applications. Though Rayleigh fading is an excellent approximation in a large number of practical scenarios, there are scenarios where it is not valid. The Rician model can be shown to exhibit a smaller number of deep fades; the stronger the Line-of-Sight (LOS) component, the rarer the occurrence of deep fades. In this paper, the performances of both the Rayleigh and Rician fading channels are analyzed under frequency-selective fading, in terms of error probability, and it is shown that due to the presence of an LOS component, the Rician fading exhibits less error probability than the Rayleigh fading.

© 2010 IUP. All Rights Reserved.

Grid-Connected PV System for PID Controller Using Matlab

-- R Sivakumar and N Suthanthiravanitha

This paper presents a single-phase five-level photovoltaic (PV) inverter topology for a grid-connected system. The PV arrays are connected to a five-level inverter. By implementing maximum power point tracking algorithm, more power is produced from the PV array. The DC power from the PV array is applied to PWM inverter, which is controlled by the PID controller. The output of the inverter is AC supply, which is connected to the grid. A digital Proportional-Integral-Derivative (PID) current control algorithm is implemented in MATLAB version 7.5. Dynamic performance of the grid current is almost sinusoidal. The total harmonic distortion produced by the inverter is less.

© 2010 IUP. All Rights Reserved.

Design of a Wireless Audio Link for a Farm Settlement in the North Central Area of Nigeria

-- Paul Abraham-Attah, John Jiya Musa and Yahaya Dantani Daudu

The wireless audio link is aimed at transmitting audio using high power infrared beam frequency modulation within a localized farm settlement. The modulation is designed with a linear audio amplifier that drives two infrared diodes connected in series across a distance which is a function of power delivered to the diodes. Distance covered varies with a frequency of 100 kHz. This study uses a headphone capable of picking up distant sound signals with a high-gain preamplifier, a pre-emphasis circuit, an automatic gain control, limiting circuit and an FM pulse width modulator.

© 2010 IUP. All Rights Reserved.

Condition-Based Predictive Maintenance Strategy for Electrical Machines: A User's Perspective

-- Jaideep Gupta, A K Wadhwani and S Wadhwani

Electrical machines are widely used in all areas of modern life in domestic and industrial applications. In a large system, these machines are used to fulfil a number of objectives either independently or as a part of a complex process, employing a number of such units. To ensure the optimum performance of these machines, a number of maintenance strategies are used. This paper gives some insight into different maintenance techniques and presents some views on how a condition-based predictive maintenance strategy can be successful in today's competitive and legislative environment. Any maintenance strategy must ensure that all necessary work is carried out without wasting any time on activities which are not really needed. The goal must be to ensure that the safety and integrity of the installation are maintained, while at the same time, allowing all production targets to be met in a cost-effective manner.

© 2010 IUP. All Rights Reserved.