Browsing Department of Physics by Title

Browsing Department of Physics by Title

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  • Calibration of the rolling angle of a Quadrant Photo Detector mounted in the image plane of a dark-field passive LIDAR system 
    Abeywickrama, S S; Perera, H E; Jayaweera, H H E (Faculty of Science, University of Kelaniya, Sri Lanka, 2020)
    Passive Light Detection and Ranging (LIDAR) has successfully been used for observing insects and their activities. It was reported that such techniques are more efficient compared to traditional approaches. Quadrant Photo ...
  • Century Scale Climate Change in the Central Highlands of Sri Lanka 
    De Silva, J.; Sonnadara, D.U.J. (2016)
    ABSTRACT An analysis of century scale climate trends in the central highlands of Sri Lanka is presented. Monthly rainfall and temperature records of the period 1869 – 2006 from five climatological stations were analyzed. ...
  • The changing shape of a liquid drop in an electric field 
    Jayalal, A.A.S.N; Wijewardena, Gamalath K.A.I.L. (2012)
    An approximate extension of the slender body theory was used to determine the static shape of a conically ended dielectric fluid drop in an electric field. Using induced surface charge density, hydrostatic pressure and the ...
  • Channel Tortuosity of Long Laboratory Sparks 
    Amarasinghe, D.; Sonnadara, D.U.J.; Berg, M.; Cooray, V. (2007)
    Channel tortuosity of 50 cm long laboratory sparks were measured by analyzing a set of images taken by three cameras. The cameras were placed at a radial distance of 200 cm from the spark gap. The angle between any two ...
  • Characteristics of chaotic pulse trains generated by Lightning flashes 
    Gomes, C.; Cooray, V.; Fernando, I.M.K.; Montano, R.; Sonnadara, D.U.J. (2004)
    Pulse trains of irregular pulse characteristics and erratic amplitudes are observed in lightning flashes. These are termed ‘‘chaotic pulse trains’’ in this study. The average width of the individual pulses of these pulse ...
  • Characteristics of cloud to ground lightning flashes 
    Sonnadara, D.U.J.; Cooray, V.; Gotsch, T. (2006)
    A detailed study on the characteristics of cloud-to-ground lightning flashes over Sweden was carried out for the period 1987 to 2000 using the data obtained from the Swedish lightning locating network. Results are presented ...
  • Characteristics of Narrow Bipolar Pulses observed from lightning in Sri Lanka 
    Gunasekara, T.; Fernando, M.; Sonnadara, D.U.J.; Cooray, V. (2016)
  • Classification of Birds using FFT and Artificial Neural Networks 
    Abewardana, Anuradha; Sonnadara, D.U.J. (2012)
    The use of feed-forward artificial neural network to categorize a selected set of Sri Lankan bird species based on their vocalization is presented. The inputs to the neural network were frequencies of bird vocalizations ...
  • Classification of Coir Fibres using Machine Vision 
    Chamara, M.W.T.; Sonnadara, D.U.J. (2011)
    Measuring the length and the width of a sample of coir fibres manually is a time consuming and labour intensive task. With the aim of developing an imaging system based on machine vision, automatic computing of length ...
  • Classification of Rice Grains Using Neural Networks 
    Silva, C.S.; Sonnadara, D.U.J. (Institute of Physics, Sri Lanka, 2013)
    ABSTRACT This paper presents a neural network approach for classification of rice varieties. A total of 9 different rice verities were considered for the study. Samples were drawn from each variety and images of seeds ...
  • Classification of Rice Grains Using Neural Networks 
    Silva, Chathurika Sewwandi; Sonnadara, D.U.J. (Institute of Physics, Sri Lanka, 2013)
    ABSTRACT This paper presents a neural network approach for classification of rice varieties. A total of 9 different rice verities were considered for the study. Samples were drawn from each variety and images of seeds ...
  • Climate change in the hill country of Sri Lanka 
    De Silva, G.J.; Sonnadara, D.U.J. (2009)
    This paper describes an analysis of long term changes in precipitation and temperature over 5 stations in the hill country of Sri Lanka during the period 1869 – 2006. The trend is predicted by a least squares regression ...
  • Climate Change Projections Over Sri Lanka 
    A Thevakaran; J. McGregor; J Katzfey; M Thatcher; R Suppiah; U Sonnadara (University of Colombo, 2017)
    This paper investigates the future climate of Sri Lanka using the variable-resolution Conformal Cubic Atmospheric Model (CCAM) developed at CSIRO, Australia. Bias corrected sea surface temperatures (SSTs) and sea ice ...
  • Climatology of lightning flash activities over Sri Lanka 
    Sonnadara, D.U.J.; Jayawardena, Wasana; Fernando, Mahendra (Springer, 2019)
  • Collision Detection through Optical Flow 
    Sandaruwan, S.; Illeperuma, G.; Sonnadara, D.U.J. (IPSL, 2016)
    In this paper, an analysis of collision detection via optical flow is presented. The main objective of the work is to detect and initiate a warning signal when there is a non-moving object or a moving object (such as a ...
  • Colour Image Segmentation Technique for Screen Printing 
    Hewage, R.U.; Sonnadara, D.U.J. (2011)
    Screen-printing is an industry with a large number of applications ranging from printing mobile phone logos to printing artworks on fabrics. In screen-printing, image segmentation plays a critical role in deciding both ...
  • Community response to road traffic noise 
    Kalansuriya, C.M.; Pannila, A.S.; Sonnadara, D.U.J. (2008)
    A study was carried out to determine community response to noise levels in the vicinity of traffic routes. Noise levels in category A, B and C grade roads were measured and the responses of the residents living within 25 ...
  • A comparison between some characteristics between positive and negative cloud to ground flashes observed in Sri Lanka and their seasonal variations 
    Sonnadara, D.U.J.; Fernando, I.M.K.; Weerasekera, A.B.; Liyanage, J.P. (2000)
    Using a system of two Direction Finding (DF) stations, a total of 4120 cloud to ground (CG) flashes were recorded for 34 days during the months of February, May, June, August, September and October in 1999. It was observed ...
  • Comparison of Firmness of Tomato Varieties Grown in Sri Lanka 
    Ranatunga, C. L.; Hiran H. E. Jayaweera; Ariyaratne, T. R. (2008)
    Firmnesses of farm fresh samples of three tomato (Lycopersicon esculentum) varieties grown in Sri Lanka, named, Maheshi, HF-2 and T-146 were studied. The firmness of the tomatoes was measured using Effegi type Bishop FT ...
  • Comparison of FFT and Maximum Entropy Method in Sinhala Speech Recognition 
    Sonnadara, D.U.J.; Nanayakkara, A.; Jayananda, M.K.; Sonnadara, D.U.J. (1998)
    With the recent advancement of computer technology, communicating with the computer through human voice has become a reality. There has been tremendous progress made on speech recognition in English and other European ...

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