Coherent optical communication systems promise superior performance, but their realization in real time also poses big technical challenges. After an introduction the potential of coherent optical transmission systems is shown as manifested in offline experiments. Then we present key components that are necessary to realize these systems in real time. We review recent achievements in realtime coherent communication and finally present the results of a realtime QPSK transmission system with a 3x3 coupler in the receiver. The achieved BER at a data rate of 1.4 Gbit/s is well below the FEC threshold.

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(frigate tuna), is a commercially fortunate to have a large resource of tuna, little information is available on the biology, genetics and stock structure of. Hence, the present study was conducted to study the biology, genetics and stock structure of in coastal October 2015 to September 2017 from day-boats operating in of Sri Lanka. For this period, the length-weight relationship and Fulton's condition factor (K) calculated for using standard length measured in centimetres and weight measured in grams were shown as = 0.1091 3.3385 and 1.93, respectively, indicating a relatively healthy growth pattern and a comparatively unpolluted habitat. Studies on the stomach contents revealed that are non-selective carnivors, shrimps and cephalopods available in the surrounding waters. The fecundity of female was shown to be 48,056 to 267,000 eggs. The calculated GSI values showed that the peak spawning period for male extends from May to August and for the females from May to July. The phylogenetic analysis of the mitochondrial D-loop region sequences of 75 selected samples representing all the geographical regions found in the coastal waters of the Western, North be considered as a single stock.

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This paper proposes a spectral clustering based methodology to classify video events and to detect anomalies. Feature trajectories from objects in a video are modelled, compared and clustered in order to classify the detected object events. Principles of normalized spectral clustering are used with modifications to affinity structure. A novel method for determining spectral clustering parameters based on Eigen structure of the affinity matrix is introduced. Employment of unsupervised learning for event classification is made possible by the proposed successive cluster identity labelling algorithm. A mechanism to identify abnormal events under the context is also introduced. The effectiveness and the robustness of the proposed methodology are demonstrated through experiments conducted on video streams focusing on human motion patterns.