In this paper, a new method is presented for encryption of colored images. This method is based on using stack data structure and chaos which make the image encryption algorithm more efficient and robust. In the proposed algorithm, a series of data whose range is between 0 and 3 is generated using chaotic logistic system. Then, the original image is divided into four subimages, and these four i...

Over the past two decades, quick development of wireless sensor networks has required nodes being self-powered. Pushed by this goal, in work, we demonstrated a ZnO nanowire-array-based piezoelectric nanogenerator (NG) prototype, which can convert mechanical energy into electricity. High-quality single crystalline nanowires, having an aspect ratio about 15, grown on gold-coated silicon substrate...

When a marble rolls down a sloped surface it eventually oscillates about a low point. With friction, it finally comes to a rest at the low point. Electrons are pulled towards an atomic nucleus like the marble is pulled downhill towards a low point by gravity. There are no frictional forces on the electron, but an electron circling around a nucleus creates radiation and these electromagnetic wav...

To understand the interplay between environmental stochasticity and Allee effects, we analyse persistence, asymptotic extinction, and conditional persistence for stochastic difference equations. Our analysis reveals that persistence requires that the geometric mean of fitness at low densities is greater than one. When this geometric mean is less than one, asymptotic extinction occurs with high ...

We study invasion speeds in the Lotka-Volterra competition model when the rate of diffusion of one species is small. Our main result is the construction of the selected front and a rigorous asymptotic approximation of its propagation speed, valid to second order. We use techniques from geometric singular perturbation theory and geometric desingularization. The main challenge arises from the slo...

A lack of diversity permeates the science, technology, engineering, and mathematics (STEM) field. Under-representation within STEM fields can stifle innovation progressive approaches to future STEM. Traditional pathways focus on identifying participants who show academic promise in schools. One segment young people, youth have been ‘pushed out’ high schools, often excluded from pathways. Altern...

With the increase in pace of globalization, SMEs are facing stiff competition from multinational firms. The entrepreneurs owning have fewer funds, but they need to improve output their organizations. Technology adoption can help owners match up with firms because it reach and overall performance. In this paper, authors will discuss whether online resource (social media, e-commerce, technology 4...

the sources of output growth of iranian agriculture over the years 1986-2001 has been examined, using a decomposition method within the input-output (io) framework. the three comparable io tables of 1986, 1991, and 2001 have been employed as the main data sources. output changes from a demand side perspective, and decomposition of the growth of output into components attributable to consumption...

Four puzzle boxes were used to investigate localized stimulus enhancement and object movement reenactment (OMR) in 13 pig-tailed macaques (Macaca nemestrina) and 30 human infants (Homo sapiens). Participants received contrasting demonstrations on each box. A circular lid was gripped by its rim or handle and swiveled to the left or right. A flap door was pushed or flipped. A sliding lid was push...