Signal Rate Research Articles

Proposed Technique for Encryption JPG and BMP Images

The technique of chaotic system is considered one of the applications for high security encryption, where a color images sent is encrypted for the purpose of preserving from hacker futility. The color images which are used to study are in both formats JPG and BMP. This paper deals with the method of the numeric encryption key to encrypt each one of the two formats type images and then decrypt the result images using the same key. The measures where used to study the statistical characteristics of result images are the histogram of images, original signal divided by noise signal rate (SNR), maximum squared errors (MSE) and peak signal to the noise rate (PSNR). It is found that the chaotic key with control parameter (r) in rang (3.4567-- 4) and initial value(x) within rang (0.6716 -- 1) make high mixing. Encryption results for BMP color images are very good and efficiently, because of the decryption process given the same input image and have the same pixels values without any loosed values. The result of encryption technique for the color images in JPG format is given a little and acceptable loss because of resaving process for resaving output images using compress data in jpg format algorithm.

Ultrasonic Signal Competition Between Male Wax Moths

Pair formation in the lesser wax moth, Achroia grisella (Lepidoptera: Pyralidae), is effected by male ultrasonic signals that are attractive to receptive females within 1-2 m. The males typically aggregate in the vicinity of the larval food resource, honeybee colonies, and signal for 6-10 h each night. Females are known to choose males on a relative basis and evaluate primarily three signal characters: signal rate (SR), loudness (peak amplitude; PA), and asynchrony interval (AI), a temporal feature reflecting the time interval between signals produced by the left and right tymbals. We conducted a series of experiments to investigate whether and how A. grisella males modify their signals in the presence of neighboring signalers. When separated by <40 cm, males increase their SRs by 3-6% upon perceiving a neighbor's signals, but they do not alter their PAs or Als. Increased SRs continue for 5-10 min and are more pronounced in males that are silent at the time they perceive their neighbor. By increasing its SR, a male improves the likelihood of matching or exceeding its neighbor's SR and may thereby compete more effectively for local females. SR increases are energetically demanding, though, and their brief duration and occurrence primarily at the beginning of signaling bouts may be the most prudent allocation of a male's limited energy reserves.

Genetic variance of sexually selected traits in waxmoths: maintenance by genotype x environment interaction.

When traits experience directional selection, such as that imposed by sexual selection, their genetic variance is expected to diminish. Nonetheless, theory and findings from sexual selection predict and demonstrate that male traits favored by female choice retain substantial amounts of additive genetic variance. We explored this dilemma through an ecological genetic approach and focused on the potential contributions of genotype x environment interaction (GEI) to maintenance of additive genetic variance for male signal characters in the lesser waxmoth, Achroia grisella (Lepidoptera: Pyralidae). We artificially selected genetic variants for two male signal characters, signal rate (SR) and peak amplitude (PA), that influence female attraction and then examined the phenotypic plasticity of these variants (high- and low-SR and high- and low-PA lines) under a range of environmental conditions expected in natural populations. Our split-family breeding experiments indicated that two signal characters, SR and PA, and several developmental characters in both high- and low-SR and high- and low-PA lines displayed considerable phenotypic plasticity among the environments tested. Moreover, strong GEIs leading to crossover between high- and low-SR lines were found for SR and developmental period. Therefore, neither high- nor low-SR genetic variants would achieve maximum attractiveness and fitness in every environment, and those variants producing unattractive signals with low SRs under normal conditions may remain in populations provided that gene flow across environments or generation overlap are sufficiently high. We speculate that the phenotypic plasticity for SR and developmental period is adaptive in A. grisella populations experiencing a range of temperature and density conditions. Females mating with attractive (high-SR) males may be assured of obtaining good genes because these males sire offspring that develop more rapidly and a crossover for developmental period may parallel that for SR. Such parallel crossovers may be expected wherever good-genes sexual selection mechanisms operate.

GENETIC VARIANCE OF SEXUALLY SELECTED TRAITS IN WAXMOTHS: MAINTENANCE BY GENOTYPE × ENVIRONMENT INTERACTION

When traits experience directional selection, such as that imposed by sexual selection, their genetic variance is expected to diminish. Nonetheless, theory and findings from sexual selection predict and demonstrate that male traits favored by female choice retain substantial amounts of additive genetic variance. We explored this dilemma through an ecological genetic approach and focused on the potential contributions of genotype × environment interaction (GEI) to maintenance of additive genetic variance for male signal characters in the lesser waxmoth, Achroia grisella (Lepidoptera: Pyralidae). We artificially selected genetic variants for two male signal characters, signal rate (SR) and peak amplitude (PA), that influence female attraction and then examined the phenotypic plasticity of these variants (high- and low-SR and high- and low-PA lines) under a range of environmental conditions expected in natural populations.Our split-family breeding experiments indicated that two signal characters, SR and PA, and several developmental characters in both high- and low-SR and high- and low-PA lines displayed considerable phenotypic plasticity among the environments tested. Moreover, strong GEIs leading to crossover between high- and low-SR lines were found for SR and developmental period. Therefore, neither high- nor low-SR genetic variants would achieve maximum attractiveness and fitness in every environment, and those variants producing unattractive signals with low SRs under normal conditions may remain in populations provided that gene flow across environments or generation overlap are sufficiently high. We speculate that the phenotypic plasticity for SR and developmental period is adaptive in A. grisella populations experiencing a range of temperature and density conditions.Females mating with attractive (high-SR) males may be assured of obtaining good genes because these males sire offspring that develop more rapidly and a crossover for developmental period may parallel that for SR. Such parallel crossovers may be expected wherever good-genes sexual selection mechanisms operate.Corresponding Editor: K. Ross

A connectionist approach to rate adaptation

In previous work [2], we presented a technique for automatically adapting to the rate of an incoming signal. The idea is as follows: First, a model of the signal is built using a recurrent neural network trained to predict its input at some delay, for a "typical" rate of the signal. Then, with the weights fixed, the time constant of the network is adapted using gradient descent. The time constant controls the processing speed of the network; thus, by adjusting the time constant, we adapt the network's processing rate to match that of the input signal.This method has previously been applied to several signals: sets of sine waves differing in frequency and in phase, a multidimensional signal representing the walking gait of children, and the energy contour of a simple speech utterance. This paper describes experiments on a voicing distinction task using simulated speech data. Results indicate that, using data at only a few rates, our rate adaptation technique can be used to train a system which can then adapt to other rates not represented in the training set. Furthermore, the network's time constant appropriately reflects rate changes in the input signal and can be used as a measure of the signal's rate. We will discuss how this technique can be used to build speech systems that are robust to speaking rate variation.

VIBROSEIS SIGNALS WITH PRESCRIBED POWER SPECTRUM*

AbstractFor a swept frequency signal with constant envelope the power spectral density is approximately inversely proportional to the signal's rate of frequency change. Hence, by means of this relation, the phase function which describes the sweep's frequency variation may be derived from a predefined power spectrum. This is in contrast to the present use where the power spectrum is the result of a rather arbitrarily chosen phase function.A numerical algorithm based on the relation between power spectrum and phase function was found to lead to sweeps whose power spectra matched the prescribed ones rather closely.

Testing of scaleless measuring instruments

The article deals with four methods which are intended for continuous automatic testing of scaleless measuring instruments and raise considerably the precision and efficiency of testing. Three of them can, in many instances, be used without developing special equipment. Continuous testing provides an incomparably larger amount of information about the qualitative condition of the tested instruments than normal discrete static testing, thus serving to obtain a technical diagnostic of instruments both under adjustment and quality control conditions. This makes it possible to reduce considerably the number of failures in the course of operation by eliminating in time the instruments' defects which in normal testing remain undiscovered. Continuous automatic testing simplifies prolonged testing of instruments for reliability and evaluation of their reliability parameters. The testing methods under consideration provide in principle the possibility of determining the tested instruments' dynamic errors with respect to the input signal's rate of change.