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<p>Maximum power point tracking (MPPT) algorithms are employed in photovoltaic (PV) systems to make full utilization of PV array output power, which have a complex relationship between ambient temperature and solar irradiation. The power-voltage characteristic of PV array operating under partial shading conditions (PSC) exhibits multiple local maximum power points (LMPP). In this paper, an advanced algorithm has been presented to track the global maximum power point (GMPP) of PV. Compared with the Perturb and Observe (P&amp;O) techniques, the algorithm proposed the advantages of determining the location of GMPP whether partial shading is present.</p>

In the aim to contribute to the security of medical image, we present a robust watermarking method which combines discrete wavelet transform (DWT), discrete cosine transform (DCT) and singular value decomposition (SVD). This approach is intended to insert an invisible image watermark in a medical image. The cover medical image is divided up into the third level of DWT coefficients and then is transformed by DCT and SVD. The same procedure is applied to the watermark image. The singular value of watermark is inserted into the singular value of the high-frequency sub bands of the third level DWT of the cover image. However, the insertion of the watermark in these areas makes it possible to reinforce the robustness of the system of watermarking without hindering the quality of the watermarked image. The performance of the proposed method was evaluated in term of invisibility by calculating the Peak Signal to Noise Ratio (PSNR) between the original and the watermarked image and in term of robustness by measuring the normalized correlation coefficient (NC) between the original watermark and the extracted watermark after applying attacks. The experimental results approve that our proposed hybrid algorithm gives an excellent compromise imperceptibility and robustness against several attacks such as Gaussian noise, Saltand-Pepper, Speckle noise, Average filter, Median filter, and Wiener filter compared with existing methods.

Convolutional neural network features are becoming the norm in instance retrieval. This work investigates the relevance of using an of the shelf object detection network, like Faster R-CNN, as a feature extractor for an image-to-video face retrieval pipeline instead of using hand-crafted features. We use the objects proposals learned by a Region Proposal Network (RPN) and their associated representations taken from a CNN for the filtering and the re-ranking steps. Moreover, we study the relevance of features from a finetuned network. In addition to that we explore the use of face detection, fisher vector and bag of visual words with those CNN features. We also test the impact of different similarity metrics. The results obtained are very promising.

In the recent years the development in communication systems requires the development of low cost, minimal weight and low profile antenna that is capable of maintaining high performance over a wide spectrum of frequencies. This technological trend has focused much effort into the design of a microstrip patch antenna. The aim of this paper is to design and simulate a rectangular microstrip patch array antenna using HFSS software "Ansoft-High Frequency Structure Simulator" and compare the performance of 2 elements, 4 elements, 8 elements, and 16 elements patch arrays with that of a single patch for the same operating frequency. Also comparisons are made between the performance of series, corporate and series-corporate feed network in terms of return loss, gain, directivity and radiation pattern. Details of simulated results are presented and discussed. Enhancement in gain, directivity and better return loss performance can be obtained by the use of RT-DURROID substrate because Low dielectric constant substrates are generally preferred for maximum radiation. Quarter wave transformer and power divider are used to feed the elements. These arrays are designed to operate at a frequency of 10 GHz. Our goal is to obtain a high directivity with better gain and reduced losses, to be especially used for X band applications such as satellite communication, radar, medical applications, and other wireless systems.