The Modares Journal of Electrical Engineering
Volume:10 Issue: 4, 2011

This paper presents a new method called vespiary regular hexagonal (VRH) model to calculate parasitic capacitance between conductor wire filaments of one turn of a coil and between conductor wires filament and liner and also total capacitance of n-turns having single-layers, multi-conductor wire filaments of the helix magneto cumulative generator (MCG) coil. The presented method is an analytical method and based on the geometrical structure of single-layer multi-conductor wire filaments with circular cross-section form in a turn of MCG coil. In this method, wire filaments of the MCG coil are divided into many very small similar elementary cells. In this structure, an equilateral lozenge shaped basic cell with two trapezium shaped regions is considered between the two adjacent conductor wire filaments in each turn of the MCG coil. This method can be applied to calculate stray capacitance of n-turns of coil with multi conductor wire filaments having the circular cross-sections and wires filament in each turn of the generator coil having wounded around linear and uniform in multi-layers in the hollow circular form and with a certain distance from the surface of the cylindrical metal liner which is placed axially in the center of the coil. Also it is seen that by the progress of the explosion and volume extension of liner and decrease of the number of MCG coil turns up to the second end turn, the total capacitance of generator increases and when it remains only one turn in the circuit, a descending decrease in total capacitance of the generator occurs.

In this paper, for the purpose of investigating horizontal sound propagation, based on the results obtained from practical measurements in the Strait of Hormoz and available data on sound speed variations at different depths, a comprehensive model for shallow water multipath underwater acoustic channel is presented. Mathematical modeling of multipath effect is based on ray theory and the image method. In channel modeling, attenuation due to wave scatterings at the surface and bottom reflections is considered. In addition, we also consider attenuations due to the absorption of sound by different materials and the presence of ambient noises such as the sea state noise, shipping noise, thermal noise and turbulence noise. Then, complete underwater communication system consisting transmitter, channel and receiver was simulated. We use QPSK modulation. Data is transmitted at a rate of 5 kbit/sec with a carrier frequency of 27 kHz, for a maximum range of 1km. The channel estimation is based on a training sequence which occupies about 10% of the signal bit rate.

The goal of facial animation is to synthesize realistic facial animated images using computer graphics. Because of its capability in creating facial animated images using a few amount of information, facial animation using feature vectors was extensively studied in recent years. In general, this method is considered as one of the performance-driven facial animation base methods. In this regard, facial feature vectors, which reflect rigid and non-rigid movements of the face, are extracted using facial analysis methods. These feature vectors are then used for transferring the facial movements to a graphical model. Our approach in this paper is merging keyframing and facial animation using feature vectors. Using this method, the amount of the submitted information is decreased to about 30%; while the synthesized sequences have 4.95% mean squared error and 0.000629 difference of correlation relative to input sequences. This error is negligible compared to the error of synthesized sequences without using interpolation.

In this paper, first, a new criterion, titled “surplus percent of the customers” is defined for static transmission expansion planning in restructured power systems. Then by a simple example, the new criterion is compared with some already presented market-based criteria and it is shown that the new criterion can realistically evaluate the transmission network expansion from the market view. In this paper the bid of market participants (producers and consumers) to sell and buy power are considered as random variables with known probability density functions. Then the expectation of the surplus percent is introduced as an index for measuring the competitiveness of each transmission expansion plan. Then a least-investment cost expansion plan that increases the surplus percent to its ideal or near ideal value is searched. In this paper a fast method is also presented to calculate the expectation of the surplus percent using Monte-Carlo simulation with a predefined approximation. The results of applying the proposed method are illustrated for an example 8-bus power system.

This paper gives a detailed analysis of direct torque control (DTC) strategy in a five-level drive and proposes a 24-sector switching table. The overvoltage problem due to high dv/dt is reduced compared to the 12-sector DTC. Using all vectors leads to better flexibility and reduces speed oscillations. Simulation and experimental results for a 3kVA prototype confirm the proposed solutions. A TMS320F2812 is used to implement the above strategy.

In a mobile ad hoc network, there are some features such as the ability to exploit multipath effect for information exchange with high reliability and low error rate. dealing with the aggressors and discovering the path in data transmission are of importance. Approaching these goals ends in network promotion and efficiency. In this paper, the designed protocol is able to discover multipath for information exchange with high reliability. The designed network has advantages such as resistance against error occurrence, decreasing the effect of the aggressors and discovering the path in data transmission. The network security is based on the desired encoding and encryption and it provides increased speed and mobility of the network performance and efficiency and reduces the weaknesses of the security system. With increasing the speed of the nodes and density of the network, the receipt of the packets increases about four percent which causes one percent increase in packets transition. At the same time packet overhead decreases 12% on average.

It has been demonstrated that anxiety is accompanied by significant warm up in the periorbital area. This warm up was attributed to the increased blood circulation in the area around the eyes. The whole pattern makes physiological and evolutionary sense since it represents a mechanism to facilitate rapid eye movements during preparedness for fight. This increased blood flow dissipates convective heat, which can be monitored through thermal imaging. The evolution of these variables along the timeline and across the 2D space can reveal important clues about anxiety. In this work, we use both facial thermal imaging analysis and poly graph examination to evaluate the effectiveness of thermal imaging in situation of anxiety. The system had been evaluated on six subjects and for each of them four times, each time in two minutes. It operates on the raw temperature signal and tries to improve the information content by suppressing the noise level instead of amplifying the signal as a whole. Finally, a pattern recognition method classifies stressful (deceptive) from non-stressful (non-deceptive) subjects based on a comparative measure between the entire baseline signal and a transient response. The successful classification rate with Multi Layer Perceptron is about 74.7% that is a little better than the LDA method.