An Oscillator without Linear Terms: Infinite Equilibria, Chaos, Realization, and Application

Oscillations and oscillators appear in various fields and find applications in numerous areas. We present an oscillator with infinite equilibria in this work. The oscillator includes only nonlinear elements (quadratic, absolute, and cubic ones). It is different from common oscillators, in which there are linear elements. Special features of the oscillator are suitable for secure applications. The oscillator’s dynamics have been discovered via simulations and an electronic circuit. Chaotic attractors, bifurcation diagrams, Lyapunov exponents, and the boosting feature are presented while measurements of the implemented oscillator are reported by using an oscilloscope. We introduce a random number generator using such an oscillator, which is applied in biomedical image encryption. Moreover, the security and performance analysis are considered to confirm the correctness of encryption and decryption processes.

AVANT-GARDE DIALOGUES

The article is dedicated to comparative analysis of spatial constructions created by the Russian Avant-Garde Artist Alexander Rodchenko and the famous kinetic European and American artist Alexander Calder in the first half of the 20-th century. For both artists technology played the decisive role in constructing spatial objects, both of them used line as a basic expressive element. Still there is a certain difference stressed by the author: Rodchenko used linear elements to express structural and constructive qualities of spatial objects, while Calder was more intending to represent emotion and movement. Rodchenko and Calder belong to the common abstract artistic trend in 20th century sculpture. But their works served as the basis for the two different traditions: minimalist conceptual and geometric art of Donuld Judd on one side and spontaneous mechanisms of Jean Tinguely on the other.

Rec8 cohesin-mediated loop-axis chromatin architecture is required for meiotic recombination

During meiotic prophase, cohesin-dependent axial structures are formed in the synaptonemal complex (SC). However, the functional correlation between these structures and cohesion remains elusive. Here, we examined the formation of the cohesin-dependent axial structure in fission yeast, which forms atypical SCs composed of linear elements (LinEs) resembling the lateral elements of SC but lacking the central elements. The results demonstrated that Rec8 cohesin is crucial for the formation of the loop-axis structure within the atypical SC. Furthermore, the Rec8-mediated loop-axis structure is formed in the absence of LinEs and provides a structural platform for aligning homologous chromosomes. We also identified a rec8 mutant that lost the ability to assemble the loop-axis structure without losing cohesion. Remarkably, this mutant showed defects in the LinE assembly, resulting in a significant reduction in meiotic recombination. Collectively, our results demonstrate an essential role for the Rec8-dependent loop-axis structure in LinE assembly, facilitating meiotic recombination.

A machine learning approach to predict the stress results of quadratic tetrahedral elements

Industries are always looking for an effective and efficient way to reduce the computation time of simulation because of the huge expenditure involved. From basics of Finite Element Method (FEM), it is known that, linear order finite elements consume less computation time and are less accurate compared to higher order finite elements say quadratic elements. An approach to get the benefit of less computation cost of linear elements and the good accuracy of quadratic elements can be of a good thought. The methodology to get the accurate results of quadratic elements with the advantage of less simulation run time of linear elements is presented here. Machine Learning (ML) algorithms are found to be effective in making predictions based on some known data set. The present paper discusses a methodology to implement ML model to predict the results equivalent to that of quadratic elements based on the solutions obtained from the linear elements. Here, a ML model is developed using python code, the stress results from Finite Element (FE) model of linear tetrahedral elements is given as the input to it to predict the stress results of quadratic tetrahedral elements. Abaqus is used as the FEM tool to develop the FE models. A python script is used to extract the stresses and the corresponding node numbers. The results showed that the developed ML model is successful in prediction of the accurate stress results for the set of test data. The scatter plots showed that the Z-score method was effective in removing the singularities. The proposed methodology is effective to reduce the computation time for simulation.

More pests but less pesticide applications: Ambivalent effect of landscape complexity on conservation biological control

In agricultural landscapes, the amount and organization of crops and semi-natural habitats (SNH) have the potential to promote a bundle of ecosystem services due to their influence on ecological community at multiple spatio-temporal scales. SNH are relatively undisturbed and are often source of complementary resources and refuges, therefore supporting more diverse and abundant natural pest enemies. However, the nexus of SNH proportion and organization with pest suppression is not trivial. It is thus crucial to understand how the behavior of pest and natural enemy species, the underlying landscape structure, and their interaction, may influence conservation biological control (CBC). Here, we develop a generative stochastic landscape model to simulate realistic agricultural landscape compositions and configurations of fields and linear elements. Generated landscapes are used as spatial support over which we simulate a spatially explicit predator-prey dynamic model. We find that increased SNH presence boosts predator populations by sustaining high predator density that regulates and keeps pest density below the pesticide application threshold. However, predator presence over all the landscape helps to stabilize the pest population by keeping it under this threshold, which tends to increase pest density at the landscape scale. In addition, the joint effect of SNH presence and predator dispersal ability among hedge and field interface results in a stronger pest regulation, which also limits pest growth. Considering properties of both fields and linear elements, such as local structure and geometric features, provides deeper insights for pest regulation; for example, hedge presence at crop field boundaries clearly strengthens CBC. Our results highlight that the integration of species behaviors and traits with landscape structure at multiple scales is necessary to provide useful insights for CBC.

Research on influence of mesh parameters modification on solution accuracy of finite element analysis

The paper deals with the solution accuracy of the stress in the structure using the finite element analysis. In general, hexahedron elements are more accurate than tetrahedron elements and quadratic elements are more accurate than linear elements. The primary aim of the article is to perform comparison of the obtained results and calculation parameters (such as time and so on) for different types of elements and the elements size. Usage less accurate elements like linear tetrahedron under certain circumstances could lead to sufficiently accurate result of stress analysis.

RNN-based Fault Detection Method for MMC Photovoltaic Grid-connected System

Background: Fast and reliable fault detection methods are the main technical challenges faced by photovoltaic grid-connected systems through modular multilevel converters (MMC) during the development. Objective: Existing fault detection methods have many problems, such as the inability of non-linear elements to form accurate analytical expressions, the difficulty of setting protection thresholds and the long detection time. Method: Aiming at the problems above, this paper proposes a rapid fault detection method for photovoltaic grid-connected systems based on Recurrent Neural Network (RNN). Results: The phase-to-mode transformation is used to extract the fault feature quantity to get the RNN input data. The hidden layer unit of the RNN is trained through a large amount of simulation data, and the opening instruction is given to the DC circuit breaker. Conclusion: The simulation verification results show that the proposed fault detection method has the advantage of faster detection speed without difficulties in setting and complicated calculation.

THE LINE AND ICONOGRAPHY IN THE TRADITIONAL ANATOLIAN WEAVINGS

The traditional examples that continue and develop the process in Anatolian weaving are numerous for those who know how to make use of it. In 2013, during the archaeological excavations at Çatalhöyük, it was discovered in the BC. 7000 parts of linen weaving dated to were found. Due to its biological structure, humans have benefited from weaving to protect themselves from adverse weather conditions and to spend their lives more comfortably. Weavings created for natural needs are coloured to influence other people in the society and decorated with various methods. Ornamental elements start with a dot, continue with a line, and finish with colour. Weavings vary according to the cultural values conditions of the society and geographical position. Anatolian people used the line and the motifs they made by making use of the line in the decoration of their weavings. Line is a means of expression that has been used from the earliest periods of human history to the present day. One of the most important values in the cultural, artistic and sociological life of a person is the line. They have visualized pictures of weaving, which is considered a sacred profession, on many surfaces. Line has always been used as a basic element in traditional Anatolian weavings. Weavers transferred the different uses of the line to their weavings. With the arrival of the Yörüks and Turkmens from the Oghuz tribes to Anatolia, Anatolia was enriched with nomadic society weavings. There are linear elements on the basis of ornamentation of nomadic Turkish weavings. Yörük and Turkmen weavers who settled in Anatolia continued the weaving process in Anatolia until recently. In weaving patterns, they generally used line and line-based motifs. In this study; information will be given about line, iconography of line and textural surfaces created by line in Anatolian traditional weavings. Keywords: Anatolian, Weaving, Line, Iconography, Traditional.

Results of Using Alternating Presentation of Stereostimuli in Children with Functional Scotoma in Non-Paralytic Strabismus

The work is devoted to one of the actual problems of modern strabismology — the study of the ability to stereo perception in children with non-paralytic strabismus.Purpose: to study the capability to stereovision with alternating presentation of stereostimuli in children with functional scotoma in non-paralytic strabismus.Patients and methods. 113 children with functional scotoma (FS) in non-paralytic strabismus were observed. We used stereostimuli with different characteristics in the following regimes of presentation: 1) the regime of simple monocular alternating (alternate presentation of an image for the right eye and the left eye); 2) the regime having an “empty” interval (black background) between monocular phases; 3) the regime having a binocular phase (a binocular image containing details corresponding to the stimuli for the right eye and the left eye) between monocular phases.Results. It was found that in 23 (20,3 %) children, the ability to stereo perception was completely absent. All these children had stable total FS (monocular vision). In the remaining 90 children (with unstable or regional FS), the ability to stereo perception was shown with some stimuli in some modes of their alternating presentation. For stimuli with a central arrangement of linear parts, the stereo effect was possible when they were presented in an alternating mode with an “empty” interval lasting from 20 to 70 ms in combination with the duration of monocular phases from 30 to 90 ms. For stimuli with a peripheral arrangement of linear elements, 22.1 % of children were able to stereo perception not only in the “empty” interval mode, but also in the simple alternation mode. At the same time, the greatest number of children capable of stereo perception was detected when using the mode with an “empty” interval of 30–60 ms and a duration of monocular phases of 40–60 ms. With random-dot stimuli, none of the children in this group were capable of stereo perception.Conclusion. Our results suggest that even in patients with FS in non-paralytic strabismus, stereo perception is possible under the conditions of alternating presentation of stimuli with certain characteristics. In this case, the most likely appearance of a stereo effect with stimuli containing peripheral linear elements that create a stereo effect when presented in an alternating mode with an empty interval between monocular phases.