Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 6 Articles
Extensive research has been devoted to the estimation of the parameters of frequently used distributions. However, little attention\nhas been paid to estimation of parameters of Gamma/Gompertz distribution, which is often encountered in customer lifetime\nand mortality risks distribution literature. This distribution has three parameters. In this paper, we proposed an algorithm for\nestimating the parameters of Gamma/Gompertz distribution based on maximum likelihood estimation method. Iterated local\nsearch (ILS) is proposed to maximize likelihood function. Finally, the proposed approach is computationally tested using some\nnumerical examples and results are analyzed...
This study presents the behavioral model of thermal temperature and power generation of a thermoelectric-solar hybrid energy\nsystem exposed to dynamic transient sources. In the development of thermoelectric-solar hybrid energy system, studies have\nfocused on the regulation of both systems separately. In practice, a separate control system affects hardware pricing. In this study,\nan inverse dynamic analysis shaping technique based on exponential function is applied to a solar array (SA) to stabilize output\nvoltage before this technique is combined with a thermoelectric module (TEM). This method can be used to estimate themaximum\npower point of the hybrid system by initially shaping the input voltage of SA. The behavior of the overall system can be estimated by\ncontrolling the behavior of SA, such that SA can follow the output voltage of TEMas the time constant of TEMis greater than that\nof SA.Moreover, by employing a continuous and differentiable function, the acquired output behavior of the hybrid system can be\nattained. Data showing the model is obtained from current experiments with predicted values of temperature, internal resistance,\nand current attributes of TEM. The simulation results show that the proposed input shaper can be used to trigger the output voltage\nof SA to follow the TEM behavior under transient conditions....
Theinitial step towards a nondestructive technique that estimates grain orientation in an anisotropic weld is presented in this paper.\nThe purpose is to aid future forward simulations of ultrasonic NDT of this kind of weld to achieve a better result. A forward model\nthat consists of a weld model, a transmitter model, a receiver model, and a 2D ray tracing algorithm is introduced. An inversion\nbased on a multiobjective genetic algorithm is also presented. Experiments are conducted for both P and SV waves in order to\ncollect enough data used in the inversion. Calculation is conducted to fulfill the estimation with both the synthetic data and the\nexperimental data. Concluding remarks are presented at the end of the paper....
This paper presents a novel harmonic identification algorithm of shunt active power filter for balanced and unbalanced three-phase\nsystems based on the instantaneous power theory called instantaneous power theory with Fourier. Moreover, the optimal design\nof predictive current controller using an artificial intelligence technique called adaptive Tabu search is also proposed in the paper.\nThese enhancements of the identification and current control parts are the aim of the good performance for shunt active power\nfilter. The good results for harmonic mitigation using the proposed ideas in the paper are confirmed by the intensive simulation\nusing SPS in SIMULINK.Thesimulation results show that the enhanced shunt active power filter can provide the minimum%THD\n(Total Harmonic Distortion) of source currents and unity power factor after compensation. In addition, the %THD also follows\nthe IEEE Std.519-1992....
The dynamic analysis process was started after failure in some embankments during an earthquake. In this context, maximum\ndisplacement was reported at the crest based on interaction between structure and reservoir. This paper investigates the dynamic\nbehavior of short embankment on soft soil. For this purpose, numerical analysis was carried out using ANSYS13 programbased on\nfinite-element method. Simulated models were vibrated by strong earthquake, so the peak ground acceleration (PGA) and duration\nwere 0.65 g and 5.02 seconds, respectively. The comparison results were discussed in key points of plane strain analysis based on\nmodulus ratio between saturated embankment and foundation. As concluded, the modulus ratio between 0.53 and 0.66 led to\nhaving a minimum value of horizontal displacement, relative displacement in vertical direction, and shear stress. Consequently,\nthe shear stress was increased while themodulus ratio was decreased. Finally, to avoidmore rigidity in the embankment on the soft\nsoil, optimum modulus ratio was recommended at 0.66 in order to reduce the probabilistic of body cracks at the crest with respect\nto homogeneous behavior during an earthquake....
This paper defines a new procedure for optimising wind farm turbine placement by means of Monte Carlo simulation method. To\nverify the algorithm�s accuracy, an experimental wind farmwas tested in a wind tunnel. On the basis of experimentalmeasurements,\nthe error on wind farmpower output was less than 4%.Theoptimization maximises the energy production criterion; wind turbines�\nground positions were used as independent variables.Moreover, the mathematical model takes into account annual wind intensities\nand directions and wind turbine interaction.The optimization of a wind farm on a real site was carried out using measured wind\ndata, dominant wind direction, and intensity data as inputs to run theMonte Carlo simulations. There were 30 turbines in the wind\npark, each rated at 20kW. This choice was based on wind farmeconomics. The site was proportionally divided into 100 square cells,\ntaking into account a minimum windward and crosswind distance between the turbines. The results highlight that the dominant\nwind intensity factor tends to overestimate the annual energy production by about 8%.Thus, the proposed method leads to a more\nprecise annual energy evaluation and to a more optimal placement of the wind turbines....
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