Power Imbalance Detection in Smart Grid via Grid Frequency Deviations: A Hidden Markov Model based Approach

We detect the deviation of the grid frequency from the nominal value (i.e., 50 Hz), which itself is an indicator of the power imbalance (i.e., mismatch between power generation and load demand). We first pass the noisy estimates of grid frequency through a hypothesis test which decides whether there is no deviation, positive deviation, or negative deviation from the nominal value. The hypothesis testing incurs miss-classification errors---false alarms (i.e., there is no deviation but we declare a positive/negative deviation), and missed detections (i.e., there is a positive/negative deviation but we declare no deviation). Therefore, to improve further upon the performance of the hypothesis test, we represent the grid frequency's fluctuations over time as a discrete-time hidden Markov model (HMM). We note that the outcomes of the hypothesis test are actually the emitted symbols, which are related to the true states via emission probability matrix. We then estimate the hidden Markov sequence (the true values of the grid frequency) via maximum likelihood method by passing the observed/emitted symbols through the Viterbi decoder. Simulations results show that the mean accuracy of Viterbi algorithm is at least $5$\% greater than that of hypothesis test.Comment: 5 pages, 6 figures, accepted by IEEE VTC conference, Fall 2018 editio

An Automatic Gastrointestinal Polyp Detection System in Video Endoscopy Using Fusion of Color Wavelet and Convolutional Neural Network Features

Gastrointestinal polyps are considered to be the precursors of cancer development in most of the cases. Therefore, early detection and removal of polyps can reduce the possibility of cancer. Video endoscopy is the most used diagnostic modality for gastrointestinal polyps. But, because it is an operator dependent procedure, several human factors can lead to misdetection of polyps. Computer aided polyp detection can reduce polyp miss detection rate and assists doctors in finding the most important regions to pay attention to. In this paper, an automatic system has been proposed as a support to gastrointestinal polyp detection. This system captures the video streams from endoscopic video and, in the output, it shows the identified polyps. Color wavelet (CW) features and convolutional neural network (CNN) features of video frames are extracted and combined together which are used to train a linear support vector machine (SVM). Evaluations on standard public databases show that the proposed system outperforms the state-of-the-art methods, gaining accuracy of 98.65%, sensitivity of 98.79%, and specificity of 98.52%

OCCURRENCE OF LANCEFIELD GROUP C STREPTOCOCCAL SPECIES IN STRANGLES CASES OF FOALS IN PUNJAB, PAKISTAN

Three equine rearing districts of Punjab, Pakistan including Sargodha, Okara and Faisalabad were surveyed. The occurrence of strangles was highest in foals during February to the start of May compared to winter and summer seasons. Strangles-inflicted foals showed inability to eat, strangled breathing with roaring sounds, swollen submandibular and submaxillary lymph nodes, abscessation in the lymph nodes, hyperthermia and anorexia with general debilitating conditions. Morbidity and case fatality rates were 78 and 2%, respectively. Pus samples were collected from 70 foals showing burst lymph node abscesses and processed on blood agar. Typical growth showing pinpoint mucoid colonies, with beta hemolysis and catalase negative characteristics were subjected to API Strep 20 system. The isolates of streptococcus recovered from pus samples include S. equi subspecies equi (54%), S. equi subspecies zooepidemicus (11%), S. dysgalactia subspecies equisimilis (11%) and mixed isolates of S. equisimilis and S. equi (23%). Streptococcus species were found sensitive to Penicillin and Cefotoxime, whereas Gentamycine and Tetracycline were ineffective

Artificial Neural Network-Based Caprock Structural Reliability Analysis for CO2 Injection Site—An Example from Northern North Sea

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Design of wideband beamforming metasurface with alternate absorption

In this paper, we propose a periodic structure that is capable of alternating between absorption and radiation mode. The designed periodic structure consists of an array of 6×6 square shaped unit cell. Each unit cell consists of a multi-layered structure, with dimensions of 0.5¿×0.5¿. The resonators are placed on the top layer and the feeding network is designed and implemented on the bottom layer. The ground layer is sandwiched between the two dielectric substrates. All resonators are connected to a 50 feed-line using the corporate feeding technique. To achieve broadband absorption, lumped resistors are inserted into the resonators. The proposed metasurface structure achieves broadband radiation, with low RCS and high gain, in the propagation direction whereas broadband absorption is achieved, when it is exposed to a free space plane wave. Moreover, the metamaterial absorber has stable absorptivity for an incident angle of (0¿–30¿). To verify the in-band absorption and radiation of the proposed design, a 6×6 periodic array of resonators has been fabricated and experimentally verified in an anechoic chamber. The measured results validate the performed simulations.Peer ReviewedPostprint (published version