| 91. |
- Verikas, Antanas, 1951-, et al.
(författare)
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Combining neural networks, fuzzy sets, and evidence theory based approaches for analysing colour images
- 2000
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Ingår i: IJCNN 2000. - Los Alamitos : IEEE Computer Society. - 9780769506197 - 0769506194 - 0780365410 - 9780780365414 - 0769506216 - 9780769506210 ; , s. 297-302
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Konferensbidrag (refereegranskat)abstract
- This paper presents an approach to determining colours of specks in an image taken from a pulp sample. The task is solved through colour classification by an artificial neural network. The network is trained using possibilistic target values. The problem of post-processing of a pixelwise-classified image is addressed from the point of view of the Dempster-Shafer theory of evidence. Each neighbour of a pixel being analysed is considered as an item of evidence supporting particular hypotheses regarding the class label of that pixel. The experiments performed have shown that the colour classification results correspond well with the human perception of colours of the specks.
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| 92. |
- Verikas, Antanas, 1951-, et al.
(författare)
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Monitoring the de-inking process through neural network-based colour image analysis
- 2000
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Ingår i: Neural Computing & Applications. - New York, USA : Springer-Verlag New York. - 0941-0643 .- 1433-3058. ; 9:2, s. 142-151
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach to determining the colours of specks in an image of a pulp being recycled. The task is solved through colour classification by an artificial neural network. The network is trained using fuzzy possibilistic target values. The number of colour classes found in the images is determined through the self-organising process in the two-dimensional self-organising map. The experiments performed have shown that the colour classification results correspond well with human perception of the colours of the specks.
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| 93. |
- Verikas, Antanas, 1951-, et al.
(författare)
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Neural networks based colour measuring for process monitoring and control in multicoloured newspaper printing
- 2000
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Ingår i: Neural Computing & Applications. - London : Springer. - 0941-0643 .- 1433-3058. ; 9:3, s. 227-242
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a neural networks based method and a system for colour measurements on printed halftone multicoloured pictures and halftone multicoloured bars in newspapers. The measured values, called a colour vector, are used by the operator controlling the printing process to make appropriate ink feed adjustments to compensate for colour deviations of the picture being measured from the desired print. By the colour vector concept, we mean the CMY or CMYK (cyan, magenta, yellow and black) vector, which lives in the three- or four-dimensional space of printing inks. Two factors contribute to values of the vector components, namely the percentage of the area covered by cyan, magenta, yellow and black inks (tonal values) and ink densities. Values of the colour vector components increase if tonal values or ink densities rise, and vice versa. If some reference values of the colour vector components are set from a desired print, then after an appropriate calibration, the colour vector measured on an actual halftone multicoloured area directly shows how much the operator needs to raise or lower the cyan, magenta, yellow and black ink densities to compensate for colour deviation from the desired print. The 18 months experience of the use of the system in the printing shop witnesses its usefulness through the improved quality of multicoloured pictures, the reduced consumption of inks and, therefore, less severe problems of smearing and printing through.
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| 94. |
- Verikas, Antanas, 1951-, et al.
(författare)
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Training neural networks by stochastic optimisation
- 2000
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Ingår i: Neurocomputing. - Amsterdam : Elsevier. - 0925-2312 .- 1872-8286. ; 30:1-4, s. 153-172
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Tidskriftsartikel (refereegranskat)abstract
- We present a stochastic learning algorithm for neural networks. The algorithm does not make any assumptions about transfer functions of individual neurons and does not depend on a functional form of a performance measure. The algorithm uses a random step of varying size to adapt weights. The average size of the step decreases during learning. The large steps enable the algorithm to jump over local maxima/minima, while the small ones ensure convergence in a local area. We investigate convergence properties of the proposed algorithm as well as test the algorithm on four supervised and unsupervised learning problems. We have found a superiority of this algorithm compared to several known algorithms when testing them on generated as well as real data.
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| 95. |
- Vretare, Viveka, et al.
(författare)
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Influence of pressurized ventilation on performance of an emergent macrophyte (Phragmites australis)
- 2000
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Ingår i: Journal of Ecology. - Oxford, United Kingdom : Wiley-Blackwell. - 0022-0477 .- 1365-2745. ; 88:6, s. 978-987
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Tidskriftsartikel (refereegranskat)abstract
- 1 Pressurized ventilation, which increases gas exchange between aerial and submerged plant parts, has been found in various emergent macrophyte species. We investigated the potential for this mechanism to affect growth, morphology and biomass allocation in Phragmites australis in glasshouse experiments. 2 Inhibition of pressurized ventilation by perforation of stems above the water surface resulted in decreased oxygen concentrations in stem bases and rhizomes. Perforation caused little mechanical damage. 3 Allometric methods were used to evaluate treatment effects on biomass allocation and morphology. 4 Inhibition of pressurized ventilation resulted in decreased allocation to belowground weight and decreased rhizome penetration into the substrate in two of three experiments. Treatment also decreased growth rate, rhizome length and number of rhizomes when substrate had a high organic content. In the third experiment, growth clearly decreased in deep water, although inhibition of pressurized ventilation did not affect growth, biomass allocation or morphology at either of the water depths tested. 5 Decreased allocation to below-ground parts and decreased rhizome lengths may be adaptations to allow the oxygen concentration in roots and rhizomes to be maintained above a critical level when the oxygen supply is low. 6 Pressurized ventilation may improve the performance of P. australis but only under certain conditions (e.g. not when growth rate is low or the substrate has a high redox potential).
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