scholarly journals Active Reflectors: Possible Solutions Based on Reflectarrays and Fresnel Reflectors

2009 ◽  
Vol 2009 ◽  
pp. 1-13 ◽  
Author(s):  
Lorena Cabria ◽  
José Ángel García ◽  
Julio Gutiérrez-Ríos ◽  
Antonio Tazón ◽  
Juan Vassal'lo
Keyword(s):  
Evolutionary Algorithms ◽  
Radiation Pattern ◽  
Scattered Field ◽  
Active Antenna ◽  
Modulator Structure ◽  
Integration Problems ◽  
Iq Modulator ◽  
The Given ◽  
Optimal Configurations ◽  
Made In

An overview about some of the recent Spanish developments on active reflectors is presented. In the first part, a novel beamsteering active reflectarray is deeply studied. It is based on implementing in each elementary radiator an IQ modulator structure, in which amplitude and phase control of the scattered field is achieved. Finally, a special effort is made in offering solutions to overcome the active antenna integration problems. In the second part, the active concept is firstly extended to Fresnel reflectors. Thanks to the development of a proper simulator, this special structure can be easily analysed. This simulator allows the study of performance of this kind of reflectors and, applying evolutionary algorithms, to find optimal configurations of reflector in accordance with the given specifications for the conformal radiation pattern.

Formally Normal Operators Having no Normal Extensions

1965 ◽  
Vol 17 ◽  
pp. 1030-1040 ◽  
Author(s):  
Earl A. Coddington
Keyword(s):  
Hilbert Space ◽  
Linear Operator ◽  
Null Space ◽  
Normal Operator ◽  
Closed Linear Operator ◽  
Normal Operators ◽  
The Given ◽  
Densely Defined ◽  
Made In

The domain and null space of an operator A in a Hilbert space will be denoted by and , respectively. A formally normal operatorN in is a densely defined closed (linear) operator such that , and for all A normal operator in is a formally normal operator N satisfying 35 . A study of the possibility of extending a formally normal operator N to a normal operator in the given , or in a larger Hilbert space, was made in (1).

scholarly journals Optimal synthesis of a four-bar linkage by method of controlled deviation

2004 ◽  
Vol 31 (3-4) ◽  
pp. 265-280 ◽  
Author(s):  
Radovan Bulatovic ◽  
Stevan Djordjevic
Keyword(s):  
Objective Function ◽  
Optimal Synthesis ◽  
Straight Line ◽  
Individual Comparison ◽  
Four Bar Linkage ◽  
The Given ◽  
Initial Selection ◽  
Selection Of ◽  
Process Calculation ◽  
Made In

This paper considers optimal synthesis of a four-bar linkage by method of controlled deviations. The advantage of this approximate method is that it allows control of motion of the coupler in the four-bar linkage so that the path of the coupler is in the prescribed environment around the given path on the segment observed. The Hooke-Jeeves?s optimization algorithm has been used in the optimization process. Calculation expressions are not used as the method of direct searching, i.e. individual comparison of the calculated value of the objective function is made in each iteration and the moving is done in the direction of decreasing the value of the objective function. This algorithm does not depend on the initial selection of the projected variables. All this is illustrated on an example of synthesis of a four-bar linkage whose coupler point traces a straight line, i.e. passes through sixteen prescribed points lying on one straight line. .

Circles on the Complex Plane

2021 ◽  
pp. 3-12
Author(s):  
A. Girsh
Keyword(s):  
Euclidean Space ◽  
Complex Plane ◽  
Euclidean Plane ◽  
Complex Space ◽  
Radical Center ◽  
Special Cases ◽  
Different Types ◽  
Different Dimensions ◽  
The Given ◽  
Made In

The Euclidean plane and Euclidean space themselves do not contain imaginary elements by definition, but are inextricably linked with them through special cases, and this leads to the need to propagate geometry into the area of imaginary values. Such propagation, that is adding a plane or space, a field of imaginary coordinates to the field of real coordinates leads to various variants of spaces of different dimensions, depending on the given axiomatics. Earlier, in a number of papers, were shown examples for solving some urgent problems of geometry using imaginary geometric images [2, 9, 11, 13, 15]. In this paper are considered constructions of orthogonal and diametrical positions of circles on a complex plane. A generalization has been made of the proposition about a circle on the complex plane orthogonally intersecting three given spheres on the proposition about a sphere in the complex space orthogonally intersecting four given spheres. Studies have shown that the diametrical position of circles on the Euclidean E-plane is an attribute of the orthogonal position of the circles’ imaginary components on the pseudo-Euclidean M-plane. Real, imaginary and degenerated to a point circles have been involved in structures and considered, have been demonstrated these circles’ forms, properties and attributes of their orthogonal position. Has been presented the construction of radical axes and a radical center for circles of the same and different types. A propagation of 2D mutual orthogonal position of circles on 3D spheres has been made. In figures, dashed lines indicate imaginary elements.

Impact of the Slurry Pond of the Tyrnyauz Tungsten-Molybdenum Complex on the Mountain Territories Environment

2018 ◽  
Vol 931 ◽  
pp. 1070-1075 ◽  
Author(s):  
Buzgigit M. Huchunayev ◽  
Oksana O. Dakhova ◽  
Svetlana A. Bekkiyeva ◽  
Svetlana B. Hatefova
Keyword(s):  
Negative Impact ◽  
Scientific Work ◽  
Land Resources ◽  
Molybdenum Complex ◽  
Atmospheric Air ◽  
Impact Reduction ◽  
The Given ◽  
Made In

The results of the Tyrnyauz tungsten-molybdenum Plant (TTMP) slurry pond settler environment impacts assessment are given in this scientific work, and the recommendations about the negative impact reduction on the environment are made. In the given work the characteristics of the environment state are investigated: atmospheric air, water objects and land resources.

Torque Rheological Properties of Bamboo Flour/PP Composites

2011 ◽  
Vol 391-392 ◽  
pp. 138-142
Author(s):  
Wen Bin Yang ◽  
Ming Xin Zhang ◽  
En Hui Chen
Keyword(s):  
Rheological Behavior ◽  
Flow Behavior ◽  
Orthogonal Test ◽  
Weight Percentage ◽  
Two Factors ◽  
Pp Composites ◽  
Bamboo Flour ◽  
Reinforced Thermoplastics ◽  
The Given ◽  
Made In

The rheological behavior of plant flour reinforced thermoplastics composites is very important to practical industry, however few research especially research about bamboo flour reinforced polypropylene(PP) composites is available regarding rheological field. In this paper, the torque rheometer made in Shanghai was used to examine the flow behavior of bamboo flour filled PP composites. The orthogonal test was adopted to analyze how three factors(weight percentage of bamboo, weight percentage of MAPP and rotate speed) influence the behavior of composites. The result indicated that bamboo flour filled PP composites was pseudo-plastics or shear-thinning flow under the experimental condition investigated. The effect of weight percentage of bamboo on rheological peoperties was signigficant,but the effect of both of the rest of two factors on rheological was not significant under the given experimental condition.

Troița - „Răstignire” - lucrare monumentală cu caracter religios, de for public - mozaic - abordare plastică de factură contemporană amplasată în spațiul ambiental urban

2018 ◽  
Vol 32 ◽  
pp. 14-28
Author(s):  
Andrei Florian ◽  
Keyword(s):  
Technical Difficulty ◽  
Basic Structure ◽  
Stained Glass ◽  
High Complexity ◽  
Divine Inspiration ◽  
Religious Theme ◽  
Technical Solutions ◽  
The Given ◽  
Elaboration Process ◽  
Made In

The article presents briefly, in a personal vision, the execution of a public monumental work, with a religious theme, namely The Wayside Cross, with a step-by-step description of the phases of design and execution of the necessary components resulting from the project. The entire work is realized in a contemporary, personal innovative vision, and the variety of materials and techniques that were used are meant to emphasize the complexity of its building. The paper highlights the difficulties in establishing formal motives for the given theme and describes the moments when the Divine inspiration and protection were felt during the elaboration process, giving a very special note to the evolution and completion of the whole artistic approach. The mosaic - of pictorial type - is different from the slightly monochrome chromatics characteristic for the tradition of this type of monument-size representation. The basic structure of the cross pedestal, with candle shelves; the perfectly symmetrical, metallic, laced grids, of great technical difficulty; the side windows carefully made in the stained-glass technique – the Tiffany technique; the whole range of technical solutions for their installation inside the edifice that shelters the work, as well as the harmonic insertion of the complex into the ambiental atmosphere of the site, all these were challenges of high complexity. The result of this long execution process of about 5 months and its assembling in a unitary religious complex, namely the Wayside Cross, was received with real appreciation both by the priests of the parish in which it is located and by its parishioners, inhabitants of Între Lacuri district from Cluj-Napoca.

scholarly journals Design space exploration of Convolutional Neural Networks based on Evolutionary Algorithms

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Abeer Al-Hyari ◽  
Shawki Areibi
Keyword(s):  
Neural Networks ◽  
Genetic Algorithms ◽  
Evolutionary Algorithms ◽  
Convolutional Neural Networks ◽  
Design Space Exploration ◽  
Design Space ◽  
Space Exploration ◽  
Handwritten Digit ◽  
Fully Connected ◽  
The Given

This paper proposes a framework for design space exploration ofConvolutional Neural Networks (CNNs) using Genetic Algorithms(GAs). CNNs have many hyperparameters that need to be tunedcarefully in order to achieve favorable results when used for imageclassification tasks or similar vision applications. Genetic Algorithmsare adopted to efficiently traverse the huge search spaceof CNNs hyperparameters, and generate the best architecture thatfits the given task. Some of the hyperparameters that were testedinclude the number of convolutional and fully connected layers, thenumber of filters for each convolutional layer, and the number ofnodes in the fully connected layers. The proposed approach wastested using MNIST dataset for handwritten digit classification andresults obtained indicate that the proposed approach is able to generatea CNN architecture with validation accuracy up to 96.66% onaverage.

scholarly journals The Frenet Vector Fields and the Curvatures of the Natural Lift Curve

2012 ◽  
Vol 2 ◽  
pp. 38-43 ◽  
Author(s):  
Evren Ergün ◽  
Mustafa Bilici ◽  
Mustafa Çalişkan
Keyword(s):  
Vector Field ◽  
Vector Fields ◽  
Similar Calculation ◽  
Darboux Vector ◽  
Lift Curve ◽  
Curvature And Torsion ◽  
The Given ◽  
Made In

In this paper, Frenet vector fields, curvature and torsion of the natural lift curve of a given curve is calculated by using the angle between Darboux vector field and the binormal vector field of the given curve in 3/1 . Also, a similar calculation is made in 3/1 considering timelike or spacelike Darboux vector field.

scholarly journals Effect of utilization term on the quality of semi-natural grass stand in the autumn and in the winter time

2004 ◽  
Vol 52 (1) ◽  
pp. 127-136
Author(s):  
Jiří Skládanka
Keyword(s):  
Climatic Conditions ◽  
Phleum Pratense ◽  
Green Fodder ◽  
Grass Stand ◽  
Forage Utilization ◽  
Winter Time ◽  
June July ◽  
The Given ◽  
Made In

Quality of green fodder from a semi-natural sward consisting of Festuca rubra, Taraxacum officinale, Dactylis glomerata, Trisetum flavescens, Poa ssp., Agrostis stolonifera and Phleum pratense as dominant species, situated in the Bohemian-Moravian Highlands (Czech Republic) was studied in the months of the main forage utilization (November, December and January). Main usage in the winter months was preceded by usage in June, July and August (preparatory cut). The sward was fertilized in the first half of August with 50 kg N.ha-1. Qualitative characteristics studied in 2000/2001, 2001/2002 and 2002/2003 were N-substances and NEL. Sward quality was decreasing from November to January with the date of utilization exhibiting a highly significant effect (α < 0.01) on the NEL content in all three years of monitoring and on the content of N-substances in the first two years of monitoring. Effect of the preparatory cut on the contents of N-substances and NEL was significant (α < 0.05) in all three years of monitoring and in the first two years of monitoring, respectively. In November, the contents of N-substances and NEL were higher in variants with the preparatory cut made in August than in variants with the preparatory cut made in June or July. The effect of the date of preparatory cut on the contents of N-substances and NEL in December and January was depending on climatic conditions in the given year.

scholarly journals Accuracy of the typological classifications of the Late Glacial and Early Holocene osseous projectile points according to the new AMS dates of selected artifacts from Poland

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Justyna Orłowska ◽  
Grzegorz Osipowicz
Keyword(s):  
Current Knowledge ◽  
Raw Materials ◽  
Late Glacial ◽  
Early Holocene ◽  
Projectile Points ◽  
Relative Dating ◽  
Ams Dating ◽  
Processing Techniques ◽  
The Given ◽  
Made In

AbstractLate Glacial and Early Holocene bone and antler artifacts are recovered from all over the Polish Lowland. Elements of projectile weaponry, in the form of various points made of osseous raw materials, were an important part of hunter-gatherer equipment of that time. We present the results of AMS dating of a unique collection of thirteen artifacts that had previously been chrono-culturally attributed by means of relative dating using typological approaches only. The results obtained are considered alongside current knowledge and typological arrangements for these types of tools in Europe. We also attempt to determine the interpretative potential of the technological studies to which the discussed osseous points were subjected in terms of possibly identifying processing techniques that can be specific to the given periods of the Stone Age. Suggestions made in this respect are verified through the radiocarbon dating results.

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