Pattern recognition theory in nonlinear signal processing

A body of research has developed within the context of nonlinear signal and image processing that deals with the automatic, statistical design of digital window-based filters. Based on pairs of ideal and observed signals, a filter is designed in an effort to minimize the error between the ideal and filtered signals. The goodness of an optimal filter depends on the relation between the ideal and observed signals, but the goodness of a designed filter also depends on the amount of sample data from which it is designed. In order to lessen the design cost, a filter is often chosen from a given class of filters, thereby constraining the optimization and increasing the error of the optimal filter. To a great extent, the problem of filter design concerns striking the correct balance between the degree of constraint and the design cost. From a different perspective and in a different context, the problem of constraint versus sample size has been a major focus of study within the theory of pattern recognition. This paper discusses the design problem for nonlinear signal processing, shows how the issue naturally transitions into pattern recognition, and then provides a review of salient related pattern-recognition theory. In particular, it discusses classification rules, constrained classification, the Vapnik-Chervonenkis theory, and implications of that theory for morphological classifiers and neural networks. The paper closes by discussing some design approaches developed for nonlinear signal processing, and how the nature of these naturally lead to a decomposition of the error of a designed filter into a sum of the following components: the Bayes error of the unconstrained optimal filter, the cost of constraint, the cost of reducing complexity by compressing the original signal distribution, the design cost, and the contribution of prior knowledge to a decrease in the error. The main purpose of the paper is to present fundamental principles of pattern recognition theory within the framework of active research in nonlinear signal processing.

Effect of fruit maturation stage and light on seed germination of Aiphanes aculeata

Despite their spiny nature, Aiphanes palms are popular as ornamentals. They can be grown in various soil conditions, but achieve fast, luxuriant growth in sheltered positions with plenty of water. Shaded conditions are the best when plants are young. The objective of this study was to evaluate the effect of fruit maturation stage and light on the germination of seeds of A. aculeata. Fruits were collected at three different maturation stages: (1) yellow, (2) red, (3) collected on the ground without the fleshy mesocarp (removed by birds and insects). The fleshy mesocarp was also removed in treatments (1) and (2). All fruits were then treated with thiram and 25 seeds per plot were seeded in trays full of sand. The treatments (2) and (3) were subdivided in two other treatments: (a) 12 h photoperiod, (b) continuous darkness. The temperature was maintained at 30 degrees C. Seed germination began 34 days after sowing. After 160 days, the final germination percentage was (1) 54,67%, (2a) 61,33%, (2b) 65,33%, (3a) 38,00% and (3b) 45,33%. The best treatment was (2) independently of the light conditions.

Acute swimming stress induces changes in noradrenergic mechanisms in order to maintain the response pattern of the rat vas deferens to norepinephrine

This study investigated mechanisms involved in the maintenance of the functional response pattern of the postjunctional alpha(1)-adrenoceptor in vas deferens isolated from rats submitted to acute swimming stress. The plasma corticosterone levels increased approximately three times after the swimming stress in the nontreated rats as well as after swimming stress in the rats pretreated with desipramine (DMI), yohimbine (YO), or DMI with YO. No alteration was detected in the sensitivity to norepinephrine (NE) in the vasa deferentia from the stressed rats or stressed rats treated with DMI or DMI with YO, in relation to their respective control. However, when the vasa deferentia were previously incubated with DMI, a reduction in sensitivity to NE in organs from stressed rats was observed. Vasa deferentia excised from rats pretreated with YO before the swimming stress showed an increase in postjunctional alpha(1)-response that was abolished by prazosin (PZ). Thus, the neuronal uptake, the prejunctional alpha(2)-adrenoceptors (mediating prejunctional inhibition), the occupancy and functional response of the postjunctional alpha(1)-adrenoceptors, and the emotional stress component were very important for the determination of the noradrenergic response pattern in vas deferens from rats submitted to acute swimming stress. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Weed seed-germination .3. bidens-pilosa L

The germination of seeds of Bidens pilosa L. colected at different places was analyzed by dose-response curves for induction and reversion of germination in seeds pre-incubated at 25 degrees C or 36 degrees C during 24 hours. Our results indicate that phytochrome is responsible for the control of seed germination id Bidens pilosa and the level of pre-existing active form of phytochrome (Pfr) above the threshold switch the seed to germinate in darkness.

IN-VITRO INHIBITION OF SPORES GERMINATION OF ALTERNARIA-SOLANI BY 3 FUNGICIDES

In vitro inhibition of the of spores germination of Alternaria solani by iprodione, chlorothalonil, and anilazine at different dosages was studied. The highest concentration of active ingredient studied for each fungicide was equivalent to that recommended for the control of the early blight, under field conditions: 0.75; 1.80 and 1.44 g, respectively, of iprodione, chlorothalonil and anilazine per litre of water. A series of two-fold diluitions of each original concentration was studied in additional nine experiments. Eah of the three fungicides showed total in vitro spore inhibition at the highest rate, at six hours of incubation. At nine hours, only analazine mantained its full inhibition activity. The inhibition activity of iprodione decreased suddenly after 1/2 dilution, so that at the 1/8 dilution a total loss of inhibitory activity was observed. Chlorothalonil showed a progressive and slighter decrease of its activity as the dilution rate increased.Analizine showed a high inhibitory activity at higher dilutions, without any loss up to 1/128 dilution. Even at 1/512 dilution, its activity was so high that only 20% of spore germination was observed at six or nine hours of incubation.

Analysis of seed-germination in Piptadenia-Gonoacantha (Mart) MACBR (Leguminosae Mimosoideae)

Preliminary tests indicated 20-degrees-25-degrees-C as optimum temperature range to the germination of the seeds of P. gonoacantha. Seeds germinate both under light and dark conditions, although final percentage is always higher in latest condition. The transmission spectrum of the tegument was investigated and showed an enrichment of the light in far-red region which reaches the embryo. Consequently the white light inhibits partially germination. Another factor controlling germination was the water availability. Our results indicated that the excessive water available during imbibition inhibits the germination process. According to our results we propose that this species do not have a pioneer behavior and even though P. gonoacantha had been described as a riparian vegetation species, the germination process is strongly inhibited with excessive water during imbiibition process.

Effect of pre-imbibition and osmoconditioning on seed-germination in Phaseolus-vulgaris L. under water-stress

The effect of osmoconditioning and controlled water sowing was analysed in seeds of Phaseolus vulgaris L. cv. carioca on germination under water stress conditions. The pre-sowing in water at low temperature to limit germination resulted in the increase in the tolerance to water stress. The osmoconditioning with PEG for 48 hours increased the tolerance of bean seeds to water stress of -0.51MPa. The osmoconditioning or controlled water sowing can be used as a practice to increase the tolerance of bean seeds to water stress before planting in the field.

Effects of plant regulators and potassium nitrate, on Rangpur lime seeds germination

The effects of plant regulators and potassium nitrate were studied on 'Rangpur' lime (Citrus limonia Osbeck) seeds germination. The seeds were removed from ripe fruits, washed, dried and stored at 4 - 5 degrees C, and treated for 24 hours before sowing and the treatments were: KNO3 0,1% and 0,2%; GA(3) 50 ppm, 100 ppm and 250 ppm; GA(4+7)+phenylmethylaminepurine 100 ppm; phenylmethylaminepurine 20 ppm and control. The germination was evaluated begining 13 days after sowing. Best results were obtained with KNO3 0,2%, which proved most beneficial in enhancing percentage and germination rate.

Condutividade elétrica na solução de embebição de sements de soja. I. Efeito do genótipo

During the period from October/92 to September/94 experiments were carried out at the Seed Laboratory, FCAV/UNESP, Jaboticabal, SP, Brazil, using soybean seeds of different genotypes in order to evaluate the effect of genotype on the electrical conductivity (bulk conductivity) of soaked seeds. Seed moisture content (105+/-3 degrees C, 24 h), standard germination (four 50-seed samples, paper towel, 30 degrees C), and vigor-accelerated aging (42 degrees C, 48 h) were first determined. Undamaged soybean seeds were soaked in deionized water (four 50-seed samples, 75 ml, 25 degrees C, 24 h) and electrical conductivity (mu mhos.cm(-1).g(-1)) was measured. Significant differences in conductivity were observed among genotypes having the same pattern of germination and vigor. The results have showed that electrical conductivity can be significantly influenced by genotype.

Effects of direction and curvature on variable error pattern of reaching movements

A number of studies have analyzed various indices of the final position variability in order to provide insight into different levels of neuromotor processing during reaching movements. Yet the possible effects of movement kinematics on variability have often been neglected. The present study was designed to test the effects of movement direction and curvature on the pattern of movement variable errors. Subjects performed series of reaching movements over the same distance and into the same target. However, due either to changes in starting position or to applied obstacles, the movements were performed in different directions or along the trajectories of different curvatures. The pattern of movement variable errors was assessed by means of the principal component analysis applied on the 2-D scatter of movement final positions. The orientation of these ellipses demonstrated changes associated with changes in both movement direction and curvature. However, neither movement direction nor movement curvature affected movement variable errors assessed by area of the ellipses. Therefore it was concluded that the end-point variability depends partly, but not exclusively, on movement kinematics.

Relationship between carbon source, production and pattern action of alpha-amilase from Rhizopus sp

This paper discusses the inducer effect of corn soluble starch and the individual components (amylose and amylopectin) from corn and potatoes starch for alpha-amylase production by a strain of Rhizopus sp. The following decreasing order in the enzyme production was obtained: corn amylose > potatoes amylose > corn amylopectin > potatoes amylopectin > starch > maltose, coinciding with the ability of the enzyme to release reducing units, except the soluble starch that was more softly hydrolysed. However, when the enzyme action was measured by the iodine binding method, an inverse order of enzyme activity was obtained, that is: amylopectins > starch > amylosis. The results suggest that: a) branched structures in substrate affect the enzyme production; b) corn amylose and corn amylopectin are better inducers than their respectives homologous from potatoes; c) cc-amylase from Rhizopus sp has different action patterns on substrates with straight or branched chains: from the former, it removes only reducing units with lower molecular weight (G1-G3); from the latter it also removes oligosaccharides with higher molecular weight (G5-G6).

Study of spore germination in Thelypteris-dentata (forssk) e-st-john

The spore germination in Thelypteris dentata was studied and the optimum temperature of 25 C was determined by the maximum percentage germination and the highest germination index. The necessity of continuous white light irradiation and reversion of spore germination by subsequent far-red light irradiation indicate the involvement of phytochrome in the control of the process. The dependence of induction of spore germination to the continuous white light low irradiance confirms the phytochrome control through the low fluence response.