Correlating matched-filter model for analysis and optimisation of neural networks

A new formalism is described for modelling neural networks by means of which a clear physical understanding of the network behaviour can be gained. In essence, the neural net is represented by an equivalent network of matched filters which is then analysed by standard correlation techniques. The procedure is demonstrated on the synchronous Little-Hopfield network. It is shown how the ability of this network to discriminate between stored binary, bipolar codes is optimised if the stored codes are chosen to be orthogonal. However, such a choice will not often be possible and so a new neural network architecture is proposed which enables the same discrimination to be obtained for arbitrary stored codes. The most efficient convergence of the synchronous Little-Hopfield net is obtained when the neurons are connected to themselves with a weight equal to the number of stored codes. The processing gain is presented for this case. The paper goes on to show how this modelling technique can be extended to analyse the behaviour of both hard and soft neural threshold responses and a novel time-dependent threshold response is described

The Possibility of Contamination of Deep Frozen Bull Semen During Long Periods of Storage in Containers with Liquid Nitrogen

Preservation of bull sperm by deep freeze is a technological process that allows you to store semen in theory for an unlimited period of time, national and international transport, without significant loss of quality and safety of semen. According to the literature, some microorganisms successfully survive the low temperatures during storage of semen in liquid nitrogen (-196 ° C), in deep-frozen semen, seeds, and in liquid nitrogen and ice sediment in the storage container for deep-frozen bull semen. The aim of this study was to do microbiological analysis of samples semen frozen bull and liquid nitrogen in containers for bull semen storage. 414 samples of frozen bull semen, and 53 samples of liquid nitrogen ice sediment were examined. From the deeply frozen semen were isolated Candida albicans, Citrobacter freundii and Pseudomonas stutzeri. Microorganisms isolated from the storage container of frozen semen are mostly members of the family Enterobacteriacae, and Citrobacter freundii was isolated from the largest number of samples. Considering the findings of microorganisms in the semen, and liquid nitrogen, there is the possibility of connection of contamination of the semen with microorganisms of the liquid nitrogen, and reversely, as would be the goal of our future investigations

Variation of natural frequencies by circular saw blade rotation

In this paper the influence of circular saw blade rotation, slot shapes and number of slots on its natural frequencies and critical speeds is investigated. Firstly, the governing equation that describes the transverse vibrations of a stationary circular plate clamped at its centre is derived using Hamilton\u2019s principle and based on Kirchhoff-Love plate theory and von Karman strain theory. The results are then compared with the ones obtained using FEM method and the FEM method is then applied to the real circular saw blade model. Finally, influence of slot shapes and number of slots on natural frequencies and critical speeds is investigated

CCD Measurements of Double and Multiple Stars at NAO Rozhen. IV

Using the 2 m telescope of the Bulgarian National Astronomical Observatory at Rozhen observations of 30 double or multiple stars were carried out during two half nights on July 20and 21, 2009. This is the fourth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. In this paper we present the results for the position angle and separation for 23 double and 5 multiple stars (35 pairs) which could have been measured

High School Class for Gifted Pupils in Physics and Sciences and Pupils` Skills Measured by Standard and Pisa Test

The ``High school class for students with special abilities in physics`` was founded in Nis, Serbia in 2003. The basic aim of this project has been introducing a broadened curriculum of physics, mathematics, computer science, as well as chemistry and biology. We present analysis of the pupils` skills in solving rather problem oriented test, as PISA test, and compare their results with the results of pupils who study under standard curricula. Analysis of achievement data should clarify what are benefits of introducing in school system track for gifted students. Additionally, item analysis helps in understanding and improvement of learning strategies efficacy.Comment: 6 pages, Talk given at 7th International Conference of the Balkan Physical Union, Alexandruoplos, Greece, 9-13 September 2009. To be published in AIP Conf.Pro

Methanol fractionations of Catha edulis frosk (Celastraceae) contracted lewis rat aorta in vitro: a comparison between crimson and green leaves

The study investigated the effect of methanol extract and its fractionations obtained from Yemeni khat on the smooth muscle isometric tension in Lewis rat aortal ring preparations and compared the effects of the crimson and green leaves. Khat leaves were sorted into green (khat Light; KL) and crimson (khat Dark; KD) leaves, extracted with methanol, followed with solvent-solvent extraction (benzene, chloroform and ethylacetate). The contractile activity of the fractions was tested using aortal ring preparations. The control (phenylepherine contraction) methanol extracts contracted aortas at concentrations 250, 125 and 67.5 μg /1 ml buffer by 80.2% , 57.3%, 26.4% and 81.5%, 65.6% , 24.6% for KL and KD, respectively. Fractions of benzene (BF) and ethylacetate (EaF) contracted the aorta with 2μgm, whereas, chloroform (ChF) with 1 μgm / 1 ml buffer was less potent. The shape of contraction curve produced by EaF differed from that of ChF and BF of both (KL and KD). The EaF induced-contraction peaked after 3.3 ± 0.94 mins, whereas those of BF and CHF peaked after 18.0 ± 2.2, 19.7 ± 0.94 mins, respectively. Pre-incubation with nifedipine (10-6 M) insignificantly reduced the contraction induced by all fractionations, but prazosin (10-6 M) reduced the contraction by 81.9%, 63.1%, 71.8% with p= 0.23, 0.09, 0.15 for BF, ChF and EaF of KL, respectively. It significantly reduced contraction of ChF, 64.1%; p= 0.02, and of EaF, 73.5%; p= 0.04 of KD, while the reduction in contraction of BF was 63.1%; p= 0.06. In conclusion, fractions of green and crimson Yemeni khat leaves contracted aortas of Lewis rats. Both leaves behave almost similarly. Contraction induced by chloroform fraction produced alphasympathetic activity.Key words: Catha edulis, aorta contraction, rat, cathinone

Using a Total Quality Strategy in a new Practical Approach for Improving the Product Reliability in Automotive Industry

In this paper a Total Quality Management strategy is proposed, refined and used with the aim at improving the quality of large-mass industrial products far beyond the technical specifications demanded at the end-customer level. This approach combines standard and non-standard tools used for Reliability, Availability and Maintainability analysis. The procedure also realizes a stricter correlation between theoretical evaluation methods and experimental evidences as part of a modern integrated method for strengthening quality in design and process. A commercial Intake Manifold, largely spread in the market, is used as test-case for the validation of the methodology. As general additional result, the research underlines the impact of Total Quality Management and its tools on the development of innovation