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Number of results: 3
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Abstract

Underwater acoustic images are acquired using sonar instrument that uses sound propagation to navigate and map the sea floor. The sonar devices are effectively used to create images of large area of the seabed. However, the visual perception of the object in the acoustic image depends on refraction, which is a function of changes in the speed of sound in successive layers of water. And refraction depends mainly on temperature, slightly on salinity and hydrostatic pressure. The quality and resolution of sonar imaging of the bottom depends on many other factors such as pitch, yaw and heave of the side scan sonar, the presence of volume scatterers in the water body, the distance of the sonar from the bottom and orientation of the object. Generally, the objects in an acoustic image would be of small size compared to their normal size as the distance between the sonar and object is larger. To detect and recognize the objects in the images, the resolution should be enhanced. In this paper, we propose an efficient edge preserving interpolation method for underwater acoustic image resolution enhancement which preserves the edge sharpness. The method handles the diagonal pixels in the first pass, in turn fills the horizontal and vertical pixels in the second pass. The results obtained are compared with the state-of-the-art interpolation techniques and the performance measures such as Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index Measurement (SSIM) shows an improved result.
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Authors and Affiliations

R. Priyadharsini
1
T. Sree Sharmila
2

  1. Department of Computer Science and Engineering, Sri Sivasubramaniya Nadar College of Engineering, Kalavakkam, Tamil Nadu, India
  2. Department of Information Technology, Sri Sivasubramaniya Nadar College of Engineering, Kalavakkam, Tamil Nadu, India
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Abstract

European cities face urban, demographic and climate challenges. According to forecasts, annual extreme phenomena will intensify – including torrential rains. Comprehensive solutions (also those based on nature), climate adaptation strategies, runoff management, incorporation of new design (e.g. sponge cities) are urgently required in order to strengthen urban resilience and to minimise the effects of extreme weather events (droughts, floods or heat islands).
The aim of the research was to develop a methodology for activating selected elements of blue-green infrastructure within areas of natural and cultural protection as an adaptive tool of urban planning. Modelling of infiltration possibilities, programmed with SCALGO Live Poland software, was performed as a case study based on a research city – Sandomierz (in Poland). Selected parameters (stormwater surface runoff, chosen runoff areas, land cover) are strongly correlated with urban indicators relating to the vegetation coverage (biologically active area – BAA).
Results pointed out urban units, which BAA is lower than 25% (e.g. Old Town Square, courtyards of tenement houses). Modelling was carried out for these units by concentrating on the undeveloped area for which the BAA was increased. The enhancement assumed values in the range of 41–45%. In analysed cases, an improvement (decrease) in runoff volume was obtained, even by 8.69%. Simultaneously, infiltration increased by 19.61%, calculated over entire runoff area. Implementation of solutions based on these results, in the form of appropriate planning provisions, can raise the quality of environment (e.g. improving water infiltration) and life (e.g. more effective air cooling on hot nights).
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Authors and Affiliations

Barbara Warzecha
1
ORCID: ORCID
Joanna Dudek-Klimiuk
2
ORCID: ORCID

  1. Warsaw University of Life Sciences, Doctoral School, ul. Nowoursynowska 166, 02-787 Warsaw, Poland
  2. Warsaw University of Life Sciences, Faculty of Landscape Architecture, Warsaw, Poland
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Abstract

The cephalopod diet of the gentoo penguin, Pygoscelis papua and the Antarctic fur seal, Arctocephalus gazella was comparatively analyzed at Laurie Island, South Orkney Islands. A total of 125 stomach samples were collected by the water off-loading method from gentoo penguins during the autumns of 1993, 1995 and 1996, and 39 fur seal scats were collected from mid March to April 1988. Cephalopods preyed upon by gentoo penguins were represented by 1974 beaks (1628 lower, 346 upper) which occurred in 50.4% of the samples. Lower beaks identified belonged exclusively to the squid Psychroteuthis glacialis. The mean lower rostral length (LRL) of these beaks was 1.1 mm (range 0.4– 1.8 mm). From the Antarctic fur seal scats 103 beaks (41 lower, 62 upper) were removed from 60.6% of scats which contained prey remains. The cephalopod species identified were Slosarczykovia circumantarctica and P. glacialis which constituted 78.8% and 21.1% in terms of numbers, respectively. The mean lower rostral length for S. circumantarctica was 2.7 mm (range 2.0–3.5 mm), while that of P. glacialis was 1.6 mm (range 1.0–2.5 mm). The foraging behaviour of the two top predators was analyzed and discussed according to the composition and size of their cephalopod prey.

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Authors and Affiliations

Marcela M. Libertelli
Gustavo A. Daneri
Uwe Piatkowski
Nestor R. Coria
Alejandro R. Carlini

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