Разработка и исследование методов демодуляции частотно-манипулированных сигналов

The goal of our research is development and study of different demodulation techniques for a frequency shift keyed signals. The signal under study is a frequency-shift keyed (FSK) signal when the information signal regulates the carrier frequency. We consider a model imitating data transmission channels and allowing us to perform error counting. The data transmission channels have ideal synchronization. Several techniques of demodulator design are introduced for demodulating frequency-shift keyed (FSK) signal and we compare the techniques using the criterion of error number of a demodulated signal relative to a signal prior to modulation for different signal-to-noise ratio. Signal-to-noise ratio is calculated as a ratio of the energy of the information symbol to the noise power spectral density. We have tested different demodulation techniques with different signal-to-noise ratio and produced a table containing information on demodulation accuracy for different techniques. Overall, we have simulated 100 sec. of continuous bit packages. We indicate that the best results for signal-to-noise ratio exceeding 5 dB are provided with the technique based on double correlation, and for signal-to-noise ratio less than 5 dB - with the technique based on the fast Fourier transform.Предложены различные методы демодуляции частотно-манипулированных сигналов и произведено их сравнение по критерию количества ошибок демодулированного сигнала относительно сигнала до модуляции при различном отношении "сигнал/шум"

Step by step: reconstruction of terrestrial animal movement paths by dead-reckoning

Background: Research on wild animal ecology is increasingly employing GPS telemetry in order to determine animal movement. However, GPS systems record position intermittently, providing no information on latent position or track tortuosity. High frequency GPS have high power requirements, which necessitates large batteries (often effectively precluding their use on small animals) or reduced deployment duration. Dead-reckoning is an alternative approach which has the potential to ‘fill in the gaps’ between less resolute forms of telemetry without incurring the power costs. However, although this method has been used in aquatic environments, no explicit demonstration of terrestrial dead-reckoning has been presented.Results: We perform a simple validation experiment to assess the rate of error accumulation in terrestrial dead-reckoning. In addition, examples of successful implementation of dead-reckoning are given using data from the domestic dog Canus lupus, horse Equus ferus, cow Bos taurus and wild badger Meles meles.Conclusions: This study documents how terrestrial dead-reckoning can be undertaken, describing derivation of heading from tri-axial accelerometer and tri-axial magnetometer data, correction for hard and soft iron distortions on the magnetometer output, and presenting a novel correction procedure to marry dead-reckoned paths to ground-truthed positions. This study is the first explicit demonstration of terrestrial dead-reckoning, which provides a workable method of deriving the paths of animals on a step-by-step scale. The wider implications of this method for the understanding of animal movement ecology are discussed

Parental Effects On Sex Ratios In Progeny Of The European Sea Bass (Dicentrarchus Labrax)

In European sea bass (Dicentrarchus labrax), females grow 20-50% faster than males. Therefore, they are more in demand than males for commercial farming, generating much inter- est in the development of female monosex populations. Whereas most current research focus- es on the influence of temperature on sex determination, the present experiments aimed at studying parental effects on sex ratios in progeny. The study analyzed progeny resulting from a diallel crossing (2 x 2 type or a complete bi-factorial mating design), reflecting both maternal and paternal genetic relatedness among progeny. The proportion of females varied significantly among families (20.7-68.2%). There were significant maternal and paternal effects on the pro- portion of females among the progeny. The effect of the parental interaction on the sex ratio in the progeny was also significant. Parents had a significant effect on total length and body weight. Sexual growth dimorphism, in favor of females, was evident in all the full-sib families and varied significantly between families. Among offspring at 9-9.5 months (68.9±23.7 g), females were 26.6% heavier than males. It is concluded that in addition to temperature manipulation in sea bass, as proposed in earlier studies, selection of parents will probably result in an improved ratio of female to male progeny

Modified gypsum binder

Gypsum-based binder modified by clay has properties close to the gypsum binder and can be used as plaster formulations or mortars. There are several reasons and chief among them is the lack of scientific based theory of formation and hardening properties of gypsum-based binder modified by clay without additives and that modified by additives. One of the classic ways of studying the mechanism of hydration of gypsum binders is the analysis of the heat liberation: hydration heat of the binder. With the thermos method of determining the heat liberation the ambient temperature is constant and the temperature of the sample which was at the beginning of the experiment changes as a result of the released heat of hydration of the gypsum; heat exchange between sample and the environment. Heat transfer is minimized through the use of thermos technology and effective insulation. The article presents the results of studying the dynamics of heat liberation during hydration of gypsum-based binder modified by clay without additives, with addition of superplasticizer and with the addition of setting retarder. Results in all cases are satisfactory. The highest degree of hydration evaluated by kinetics of heat liberation from a binder is with the addition of the superplasticizer. Application of setting retarder somewhat reduces the maximum degree of hydration and increases the hydration time. The degree of hydration of the binder with the addition of C3 additive and retarder is observed to be higher than that of gypsum-based binder modified by clay without additives. The studies confirm the possibility of using gypsum-based binder modified by clay in the composition of dry plaster mixtures for interior decoration works in premises

A case of the kidney apparatus perfusion as a detector of errors in personnel actions. A graft edema “cure” by perfusion

Utilization of kidneys donated from uncontrolled donors after cardiac death (UDCD) became an additional source of organs for transplantation worldwide in the light of ongoing global organ shortage. Machine perfusion proven to be a promising perspective for selection, rehabilitation and treatment of kidneys from expanded criteria donors, however, exact mechanisms of these effects remains unclear. On presented clinical case we are trying to clarify the essence of them. In 2006-2007 a pilot study was carried out by our team for use of machine perfusion to perform selection of kidney obtained from UDCD and improve their quality. According to study design each couple of grafts were divided and transplanted to different recipients. During ordinary procedure a staff mistake occurred, which, fortunately, helped us to understand one of the treatment mechanisms of hypothermic machine perfusion

Comparison of sample preparation and signal evaluation methods for EPR analysis of tooth enamel.

In dose reconstruction by EPR dosimetry with teeth various methods are applied to prepare tooth enamel samples and to evaluate the dosimetric signal. A comparison of seven frequently used methods in EPR dosimetry with tooth enamel was performed. The participating Institutes have applied their own procedure to prepare tooth enamel samples and to evaluate the dosimetric signal. The precision of the EPR measurement and the dependence of the estimated dosimetric signal with irradiation up to 1000 mGy were compared. The obtained results are consistent among the different methods. The reproducibility of the dosimetric signal and its estimated relation with the absorbed dose was found to be very close for the applied methods with one possible exception

Development and Study of Demodulation Techniques for Frequency Manipulated Signals

The goal of our research is development and study of different demodulation techniques for a frequency shift keyed signals. The signal under study is a frequency-shift keyed (FSK) signal when the information signal regulates the carrier frequency. We consider a model imitating data transmission channels and allowing us to perform error counting. The data transmission channels have ideal synchronization. Several techniques of demodulator design are introduced for demodulating frequency-shift keyed (FSK) signal and we compare the techniques using the criterion of error number of a demodulated signal relative to a signal prior to modulation for different signal-to-noise ratio. Signal-to-noise ratio is calculated as a ratio of the energy of the information symbol to the noise power spectral density. We have tested different demodulation techniques with different signal-to-noise ratio and produced a table containing information on demodulation accuracy for different techniques. Overall, we have simulated 100 sec. of continuous bit packages. We indicate that the best results for signal-to-noise ratio exceeding 5 dB are provided with the technique based on double correlation, and for signal-to-noise ratio less than 5 dB - with the technique based on the fast Fourier transform