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2021 ◽  
Vol 29 (4) ◽  
pp. 280-286
Author(s):  
Ludmila Rozhkova ◽  
Tibor Krenicky ◽  
Eduard Kuznetsov ◽  
Volodymyr Nahornyi

Abstract Until recently, horizontal-axial wind turbines with blades having a wing profile occupied a predominant position in the world wind energy market. But currently, vertical-axial wind units are of increasing interest and this is understandable from the point of view of their important features as: no requirements for the orientation of the wind turbine to the wind, the possibility of placing electrical and other equipment on the ground, no requirements for changes of blade chord installation angle along its length. The article discusses the aerodynamics of the vertical-axis wind turbines: the range of changes of angles of incoming flow attack on the blade, the dynamics of changes in the magnitude of the absolute speed of flow of the blade on a circular trajectory of its movement depending on the turbine rapidity, and also obtained in experiments interaction effect of the blades in the rotor. The experiments were carried out on wind turbines with original blades (basic version), which were designed to eliminate the shortcomings of low-speed rotors Savonius (low coefficient of use of wind energy) and high-speed rotors Darrieus (lack of self-start).


2021 ◽  
Vol 2021 (2) ◽  
pp. 71-77
Author(s):  
Konstantin Aleksandrovich Klimkin

The article discusses the application of a rapid action electrical fuse with controllable overload current in the schemes of industrial and household electrical equipment. There has been found a deficiency in the basic version of the scheme. A variant of the circuit was proposed, which helps to get rid of the drawback in the basic version: if a condenser with relatively large capacity (C ≥ 100 μF) is present in the protected circuit (in the load circuit), the circuit may not reach the operating mode, because, when the condenser is on, its large charging current triggers the electronic fuse and the load remains unconnected. This situation can be avoided only if the charging current of the condenser is greatly reduced, for which a current source on a field-effect transistor VT3 and a timing circuit R10R11C1 were introduced into the circuit. As C1 is being charged, through the current source VT3 there is a smooth increase in the bias voltage at the emitter junctions of the composite transistor switch VT1VT2 with a gradual increase in its conductivity. As a result, the starting current through the capacitive load at the first moment of time turns out to be much less, and the electronic fuse enters the operating mode. The optimal relationships were found between individual elements of the circuit, their values and modes of operation, depending on the size and nature of the load, while, thanks to the use of the domestic element base, the cost of the device turned out to be minimal compared to other circuits of a similar type. The research data can be used for operation of the devices of a similar type in the household and for industrial applications.


2021 ◽  
Author(s):  
Kai Hormann ◽  
Craig Gotsman

We describe a simple and practical algorithm for compact routing on graphs which admit compact and balanced vertex separators. Using a recursive nested dissection of then-vertex graph based on these separators, we construct routing tables with as few as O(log n) entries per vertex in a preprocessing step. They support handshaking-based routing on the graph with moderate stretch, where the handshaking can be implemented similarly to a DNS lookup. We describe a basic version of the algorithm that requires modifiable headers and a more advanced version which eliminates this need and provides better stretch. A number of algorithmic parameters control a graceful tradeoff between the size of the routing tables and the stretch. Our routing algorithm is most effective on planar graphs and unit disk graphs of moderate edge/vertex density.


2021 ◽  
Author(s):  
Kai Hormann ◽  
Craig Gotsman

We describe a simple and practical algorithm for compact routing on graphs which admit compact and balanced vertex separators. Using a recursive nested dissection of then-vertex graph based on these separators, we construct routing tables with as few as O(log n) entries per vertex in a preprocessing step. They support handshaking-based routing on the graph with moderate stretch, where the handshaking can be implemented similarly to a DNS lookup. We describe a basic version of the algorithm that requires modifiable headers and a more advanced version which eliminates this need and provides better stretch. A number of algorithmic parameters control a graceful tradeoff between the size of the routing tables and the stretch. Our routing algorithm is most effective on planar graphs and unit disk graphs of moderate edge/vertex density.


Author(s):  
Lila Adana Díaz ◽  
Andrea Arango ◽  
César Parra ◽  
Alberto Rodríguez-Lorenzana ◽  
Tarquino Yacelga-Ponce

<b><i>Background:</i></b> One of the most marked problems in the use of screening instruments for the diagnosis of dementia or cognitive impairment in the elderly is the influence of educational level on the results of psychometric tests. The Montreal Cognitive Assessment (MoCA) questionnaire is one of the most widely used dementia screening instruments internationally and with greater proven validity. There is a version of this instrument called MoCA “Basic” which was developed to reduce education bias. The aim of the study was to compare the psychometric characteristics of the MoCA, full versus basic, versions in older adults. <b><i>Method:</i></b> Participants (<i>N</i> = 214) completed both versions of the MoCA, and screening measures to corroborate their health status. <b><i>Results:</i></b> Internal consistency was satisfactory in both versions: MoCA full (0.79) and MoCA basic (0.76). The overall correlation between both tests was high (0.73). There was no relationship between the dimensions included in each version. Educational level and age explained 33.8% of the total variance in MoCA Full and 31.8% in MoCA Basic. Among educational levels, there are statistically significant differences in participants with &#x3c;6 years of education. <b><i>Conclusions:</i></b> The results confirm that both versions are reliable instruments and also show that in both versions the educational level of &#x3c;6 years of education continues to have an impact on performance. Therefore, it can be considered that the MoCA Basic version for the Ecuadorian population with &#x3c;6 years of education continues to imply literacy competencies.


2021 ◽  
pp. 1-22
Author(s):  
Katherine B. Hanniball ◽  
Erin K. Fuller ◽  
Kevin S. Douglas

The Comprehensive Assessment of Psychopathic Personality (CAPP) is a lexically based conceptual model of psychopathy. Despite widespread use in research settings, the Lexical Rating Scale for the CAPP (CAPP-LRS) requires an advanced reading level for completion. The present study is the first to evaluate the content validity of the CAPP-Basic, a lexically simplified version of the CAPP-LRS designed for use with individuals possessing lower verbal skills. Symptoms were rated by mental health professionals (N = 121). Findings were largely in line with results of previous studies, indicating good content validity of the CAPP-Basic at the domain and symptom level.


10.2196/26401 ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. e26401
Author(s):  
Bianca Raffaelli ◽  
Jasper Mecklenburg ◽  
Lucas Hendrik Overeem ◽  
Simon Scholler ◽  
Markus A Dahlem ◽  
...  

Background Smartphone-based apps represent a major development in health care management. Specifically in headache care, the use of electronic headache diaries via apps has become increasingly popular. In contrast to the soaring volume of available data, scientific use of these data resources is sparse. Objective In this analysis, we aimed to assess changes in headache and migraine frequency, headache and migraine intensity, and use of acute medication among people who showed daily use of the headache diary as implemented in the freely available basic version of the German commercial app, M-sense. Methods The basic version of M-sense comprises an electronic headache diary, documentation of lifestyle factors with a possible impact on headaches, and evaluation of headache patterns. This analysis included all M-sense users who had entered data into the app on a daily basis for at least 7 months. Results We analyzed data from 1545 users. Mean MHD decreased from 9.42 (SD 5.81) at baseline to 6.39 (SD 5.09) after 6 months (P<.001; 95% CI 2.80-3.25). MMD, AMD, and migraine intensity were also significantly reduced. Similar results were found in 985 users with episodic migraine and in 126 users with chronic migraine. Conclusions Among regular users of an electronic headache diary, headache and migraine frequency, in addition to other headache characteristics, improved over time. The use of an electronic headache diary may support standard headache care.


Author(s):  
Boris Bukh ◽  
Ting-Wei Chao ◽  
Ron Holzman

Abstract Given a finite set $A \subseteq \mathbb{R}^d$ , points $a_1,a_2,\dotsc,a_{\ell} \in A$ form an $\ell$ -hole in A if they are the vertices of a convex polytope, which contains no points of A in its interior. We construct arbitrarily large point sets in general position in $\mathbb{R}^d$ having no holes of size $O(4^dd\log d)$ or more. This improves the previously known upper bound of order $d^{d+o(d)}$ due to Valtr. The basic version of our construction uses a certain type of equidistributed point sets, originating from numerical analysis, known as (t,m,s)-nets or (t,s)-sequences, yielding a bound of $2^{7d}$ . The better bound is obtained using a variant of (t,m,s)-nets, obeying a relaxed equidistribution condition.


Author(s):  
Т.С. Аббасова ◽  
В.И. Привалов ◽  
В.Г. Бондаренко

На основе анализа особенностей навигационно-временных определений и методологических основ проектирования в системах высокоточного позиционирования проведена генерация вариантов спутниковой радионавигационной системы, исходным шагом в которой является синтез её базового варианта. Рассмотрены наиболее эффективные процедуры разрешения неоднозначности фазовых измерений, основанных на избыточности фазовых измерений, а также процедуры, заключающиеся в целочисленной максимизации функции неоднозначности, выбранной из характера периодичности сигналов навигационного космического аппарата. Сформулирован критерий точности позиционирования. Based on the analysis of the features of navigation-time definitions and methodological foundations of design in high-precision positioning systems, the generation of options for a satellite radio navigation system was carried out, the initial step in which is the synthesis of its basic version. The most effective procedures for resolving the ambiguity of phase measurements based on the redundancy of phase measurements, as well as procedures involving the integer maximization of the ambiguity function, selected from the nature of the periodicity of the signals of the navigation spacecraft, are considered. A criterion for positioning accuracy is formulated.


Author(s):  
Г.О. БОКК ◽  
Р.С. АВЕРЬЯНОВ

Рассмотрена работа в режиме синхронизации системы связи стандарта МАКВИЛ, использующей организацию радиосвязи с временным дуплексом. Получен базовый вариант оптимального алгоритма обработки одиночных замеров син -хронизации, ориентированный на работу в канале с белым гауссовским шумом при неизвестных, но стабильных спектральных искажениях сигнала. На основе разработанного алгоритма предложено множество вариантов статистического накопления измерений для режима синхронизации в нестационарных условиях. На моделях многолучевого распространения, утвержденных международными рекомендациями, выявлены наилучшие варианты алгоритмов синхронизации с накоплением. Operation in synchronization mode of the McWiLL standard communication system, using the organization of radio communication with time duplex, is considered. A basic version of the optimal algorithm for processing single synchronization measurements is obtained, which is focused on working in a channel with white Gaussian noise at unknown but stable spectral distortions of the signal. Based on the developed algorithm, many variants of statistical accumulation of measurements for the synchronization mode in non-stationary conditions are proposed. Using multipath propagation models approved by international recommendations, the best variants of synchronization algorithms with accumulation are identified.


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