Model reference tracking control of an aircraft: a robust adaptive approach

This work presents the design and the corresponding analysis of a nonlinear robust adaptive controller for model reference tracking of an aircraft that has parametric uncertainties in its system matrices and additive state- and/or time-dependent nonlinear disturbance-like terms in its dynamics. Specifically, robust integral of the sign of the error feedback term and an adaptive term is fused with a proportional integral controller. Lyapunov-based stability analysis techniques are utilised to prove global asymptotic convergence of the output tracking error. Extensive numerical simulations are presented to illustrate the performance of the proposed robust adaptive controller.     

ANN-based MPPT algorithm for solar PMSM drive system fed by direct-connected PV array

In this paper, artificial neural network (ANN) based on a maximum power point tracking (MPPT) algorithm is developed for a solar permanent magnet synchronous motor (PMSM) drive system used without a boost converter and batteries. The discontinuous space vector PWM technique is used to drive two-level inverter which is directly fed by three parallel-connected Kyocera KD205GX-LP PV modules. The ANN-based MPPT algorithm estimates the voltages and currents corresponding to maximum powers produced by PV array at the maximum power point (MPP) for swiftly changing situations such as solar radiance and temperature. These maximum powers are given as input signal to vector control algorithm of PMSM. The PMSM is designed by using Infolytica/MotorSolve software so that the phase-to-phase maximum value of its operating voltage is 20 V. The use of three-phase PMSM presents more efficient solutions to the trading solar systems with dc motor or induction motor. Thus, an effective solar system is achieved. The performance of developed ANN-based MPPT algorithm, designed PMSM, vector-controlled driver and solar system is analyzed by using MATLAB/SimPowerSystems blocks under the rapidly changing environmental conditions.

     

Evaluation Method,Dataset Size or Dataset Content: How to Evaluate Algorithms for Image Matching?

Flutter shutter (coded exposure) cameras allow to extend indefinitely the exposure time for uniform motion blurs. Recently, Tendero et al. (SIAM J Imaging Sci 6(2):813–847, 2013) proved that for a fixed known velocity v the gain of a flutter shutter in terms of root means square error (RMSE) cannot exceeds a 1.1717 factor compared to an optimal snapshot. The aforementioned bound is optimal in the sense that this 1.1717 factor can be attained. However, this disheartening bound is in direct contradiction with the recent results by Cossairt et al. (IEEE Trans Image Process 22(2), 447–458, 2013). Our first goal in this paper is to resolve mathematically this discrepancy. An interesting question was raised by the authors of reference (IEEE Trans Image Process 22(2), 447–458, 2013). They state that the “gain for computational imaging is significant only when the average signal level J is considerably smaller than the read noise variance \(\sigma _r^2\)” (Cossairt et al., IEEE Trans Image Process 22(2), 447–458, 2013, p. 5). In other words, according to Cossairt et al. (IEEE Trans Image Process 22(2), 447–458, 2013) a flutter shutter would be more efficient when used in low light conditions e.g., indoor scenes or at night. Our second goal is to prove that this statement is based on an incomplete camera model and that a complete mathematical model disproves it. To do so we propose a general flutter shutter camera model that includes photonic, thermal (The amplifier noise may also be mentioned as another source of background noise, which can be included w.l.o.g. in the thermal noise) and additive [The additive (sensor readout) noise may contain other components such as reset noise and quantization noise. We include them w.l.o.g. in the readout.] (sensor readout, quantification) noises of finite variances. Our analysis provides exact formulae for the mean square error of the final deconvolved image. It also allows us to confirm that the gain in terms of RMSE of any flutter shutter camera is bounded from above by 1.1776 when compared to an optimal snapshot. The bound is uniform with respect to the observation conditions and applies for any fixed known velocity. Incidentally, the proposed formalism and its consequences also apply to e.g., the Levin et al. motion-invariant photography (ACM Trans Graphics (TOG), 27(3):71:1–71:9, 2008; Method and apparatus for motion invariant imag- ing, October 1 2009. US Patent 20,090,244,300, 2009) and variant (Cho et al. Motion blur removal with orthogonal parabolic exposures, 2010). In short, we bring mathematical proofs to the effect of contradicting the claims of Cossairt et al. (IEEE Trans Image Process 22(2), 447–458, 2013). Lastly, this paper permits to point out the kind of optimization needed if one wants to turn the flutter shutter into a useful imaging tool.     

Modeling and Predicting the Drying Kinetics of Apple and Pear: Application of the Weibull Model

Drying data of apple and pear at 40, 50, 60, 70, and 80°C were described by the Weibull model and it was observed that the shape parameter of the Weibull model did not depend on temperature. Therefore the reduced Weibull model with fixed shape parameter was proposed as the primary model to describe drying data with a slight loss of goodness-of-fit. Temperature dependence of time-parameter (time necessary to reduce the initial moisture ratio by 90%) could be described by two ad hoc models as the secondary models. Predictions using the integrated models almost perfectly agreed with the experimental drying data of apple at 45 and 65°C and of pear at 55 and 75°C, respectively. Kinetic analyses with published data have shown that the reduced Weibull model can also successfully be used to describe the drying data of certain fruits. Time-parameters tabulated in this study can be useful for food manufacturers.     

A color image watermarking scheme based on artificial immune recognition system

This study suggests a novel watermarking technique that uses artificial immune recognition system to protect color image’s intellectual property rights. The watermark is embedded in the blue channel of a color image. m-bit binary sequence embedded into the color image is used to train artificial immune recognition system. With this composed technique, extracting the watermark which is embedded into the color image is carried out using artificial immune recognition system. It is observed that the composed technique achieves high performance to process of extracting this watermark. The watermark is extracted successfully from the watermarked image after various image processing attacks as well.     

All-Grounded Passive Elements Voltage-Mode DVCC-Based Universal Filters

In this paper two new voltage-mode (VM) universal filters employing three plus-type differential voltage current conveyors (DVCC+s) and grounded passive elements are presented. The first proposed filter is a single-input five-output (SIFO) circuit which can realize simultaneously all of the standard responses, i.e. low-pass (LP), band-pass (BP), high-pass (HP), all-pass (AP) and notch (NH) from the same configuration. The second proposed circuit is a three-input single-output (TISO) universal filter for realizing standard responses depending on the selection of the input signal from the same topology. Both of the proposed filters have the advantage of a high input impedance, which enables easy cascading to obtain higher order filters. The proposed filters are simulated using the SPICE program to verify the theoretical analysis.     

Trace mineral profiles of the bivalve species Chamelea gallina and Donax trunculus

In this study, ICP-MS was used to determine concentrations of trace minerals found in these two economically important bivalvia species. Samples were collected from the Sea of Marmara in Turkey over a 12-month period in 2006–2007. The concentrations of Pb, Cu, Zn, Fe, Al, Mn, and Ni were significantly higher in Donax trunculus than in Chamelea gallina (p < 0.05). By contrast, Hg and Cd levels in C. gallina were significantly higher than in D. trunculus. Based on the limits set by the World Health Organization (WHO) and the Food and Agriculture Organization (FAO), our results suggest that these two species do not represent a risk for human consumption when the soft tissue is consumed with moderation. Highest arsenic concentrations of C. gallina and D. trunculus were found in spring samples (3.125 mg/kg and 3.669 mg/kg). Arsenic levels should be monitored in the future.     

Understanding student behavior and perceptions toward earning badges in a gamified MOOC

Universal Access in the Information Society - Despite the advantages of MOOCs, such as the open and free access to education, these courses are criticized for students’ lack of motivation and...     

Effect of partial removal of prolamins on some chemical and functional properties of barley flours

In this study, some chemical and functional properties of hulled (BF-1) and hull-less (BF-2) barley flours and their partial prolamin removed forms (PPRF-1 and PPRF-2, respectively) were determined. Total dietary fiber and resistant starch values increased on dry weight basis, conversely β-glucan levels slightly decreased after partial prolamin removing (PPR). Sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE) patterns of PPRF-1 and PPRF-2 exhibited that PPR was highly achieved. Rapid visco analyzer (RVA) peak and breakdown viscosity values of PPRF-1 and PPRF-2 were higher than BF-1 and BF-2, conversely their setback, trough, and final viscosity values were lower than that of the BF-1 and BF-2, respectively. PPR also caused an increase in water binding capacity and resulted in a decrease on water solubility values of barley flours. Protein solubility of PPRF-1 and PPRF-2 were lower than BF-1 and BF-2, respectively. Emulsifying properties of PPRF-2 were affected negatively from the PPR.