1,441 research outputs found
Stability characteristics of a supersonic boundary layer and their relation to the position of the laminar-turbulent transition point
By comparing the calculated results with experimental data, it is demonstrated that the position of the laminar-boundary transition point of a boundary layer can be estimated by using the e-exp-n method. The effect of the Mach number, pressure gradient, and heat transfer on the laminar-turbulent transition is discussed. It is found that under conditions of strong cooling, the effect of the pressure gradient on the position of the transition point is less pronounced than in the absence of heat transfer
On the dependence of the lower thermospheric wind regime on the solar cycle
The lower thermosphere occupies the intermediate position between the overlying thermospheric layers, for which direct correlation of its parameters with solar variety variations is well established, and the underlying ones, where this correlation is mainly of an indirect character. Therefore, for understanding the mechanism of solar terrestrial correlation it is important to investigate the dependence of different atmospheric parameters in the lower troposphere, and of wind regime parameters in particular, on the solar activity. Several series of observations were used which include the results of meteor radar wind velocity measurements carried out in Obninsk complemented by the data obtained using the same technique at Jodrell Bank from 1953 to 1958 and in Kharkov from 1960 to 1963. The interannual variations of values averaged over these periods for prevailing wind velocities and semidiurnal harmonic amplitudes and also results for some months are presented. These results are discussed
Сравнение отдаленных результатов монополярной и биполярной трансуретральной резекции предстательной железы
The monopolar transurethral resection of the prostate (TUR) has long remained a “gold” standard of treatment of benign prostatic hyperplasia (BPH). However, recently there have been introduced a large number of alternative noninvasive methods of BPH treatment. Modern multicenter studies demonstrate the comparability of the intraoperative data and early postoperative characteristics of the monopolar and bipolar TUR. The author of the рaper compare quality of life and nature of the long-term postoperative complications after the bipolar TUR in the period from 36 to 60 months after the operation in comparison with the monopolar TUR of the prostate. There were evaluated the frequency of BPH relapses and infravesical obstruction development, associated with the postoperative scar changes in the urethra and neck of the bladder, which was confirmed by the data of ascending urethrography and urine flowmetry. The patients with the irritative symptoms, associated with the bladder overactivity, were excluded from the study. The author demonstrates that 6.7% patients after monopolar TUR underwent repeated TUR due to BPH relapse and 13.3% of patients had the infravesical obstruction, associated with the scar changes in the zone of the surgical intervention in the long-term period after the monopolar TUR. The bipolar TUR of the prostate had advantages over the monopolar TUR in the long-term results, regarding smaller quantity of risk of BPH relapse (p<0.05) and absence of the postoperative scar changes in the zone of resection. Besides, the amount of patients contented by results of the operation is reliably more after the bipolar TUR (p<0.05).В последние годы внедрено большое количество альтернативных малоинвазивных методов лечения доброкачественной гиперплазии предстательной железы (ДГПЖ). Современные многоцентровые исследования демонстрируют сопоставимость ближайших результатов биполярной ТУР, биполярной и плазмокинетической энуклеации простаты, а также гольмиевого и green-лазера в лечении ДГПЖ по сравнению со стандартной методикой монополярной ТУР. Большинство исследований сравнивают периоперационные и ранние послеоперационные результаты биполярной и монополярной ТУР простаты. Автором статьи поставлена задача оценить качество жизни и характер отдаленных послеоперационных осложнений после биполярной ТУР в сроки от 36 до 60 мес. после операции по сравнению с монополярной ТУР предстательной железы. В результате иссле-
дования установлено, что при практически равных интраоперационных и ранних послеоперационных показателях биполярная ТУР предстательной железы имеет преимущества перед монополярной ТУР по отдаленным результатам в связи с меньшим количеством риска рецидива ДГПЖ (р<0,05) и отсутствием послеоперационных рубцовых изменений в зоне резекции
Capacity increasing of sensor telecommunication networks
A method of capacity increasing of sensor telecommunication networks has been proposed and investigated. The method proposed is based on a placement control of unmanned aerial vehicles in view of the rapid and unpredictable movement of mobile subscribers. A distinctive feature of developed method is combining mathematical models of connectivity estimation taking into account a quality of service of mobile subscribers and an advanced search algorithm of quasi-optimal placement of unmanned aerial vehicles in a single computational procedure. An application of the method proposed allows increasing the throughput of telecommunication networks to 15─20 percent in comparison with existing methods. Deviations of obtained sub-optimal solutions from optimal ones received by exhaustive method do not exceed 5─7 percent
Comparative analysis of migration policy in Russia under the reigns of Catherine II and Alexander III
This article is devoted to the social and political development of the Russian Empire under Catherine II and Alexander III. The issue of migration policy and its relationship with the economic, demographic and social indicators of the country was the purpose of this comparative study. The authors also analyze the challenges of socialization and education of human resources during the analyzed historical periods. The achievement of the main goal of the research was accompanied by a number of difficulties associated with gaps in statistical data. It was especially true for the reign of Catherine II, when the process of systematization of state documentation was in stage of formation. In these regards, the systematic work of various researchers using the retrospective method and the method of comparative analysis formed the methodological basis of the article. Despite certain restrictions related to the size of the article and the number of data used for research, it was possible to achieve the goal and reflect the main aspects of the policies of both sovereigns. As the result of the given research it was revealed that the effective migration policy of Catherine II led to the growth of the economy by attracting human resources to strategically important regions of the country. It allowed increasing development indicators, primarily in the field of agriculture and industry. The migration policy of Alexander III was more restrained and was one of the factors influencing the economy. The authors conclude that reigns of both Catherine II and Alexander III were accompanied by rapid growth of the country's economy due to the migration policies
Intelligent effective management system of biotechnical objects based on natural disturbances prediction
This article analyses Biotechnical objects as complex processes and external disturbances on them; promising areas of management systems of biotechnical objects development are identified; methodological bases for specialized algorithmic-mathematical software construction based on the methods of game theory and statistical solutions, neural networks (including genetic algorithm), filtering the noise components of information signals are synthesized and tested; variety of architectures of intelligent effective management systems of biotechnical objects are developed and tested
Energy-efficient modes for management of biotechnical objects based on natural disturbances prediction
Energy-efficient modes for management of biotechnical objects based on natural disturbances prediction. Nowadays overwhelming majority of biotechnical objects in agriculture, such as poultry houses, greenhouses etc., function under the mode of stabilization of technological parameters (air temperature, humidity etc.). This approach leads to excess consumption of energy resources (electrical energy, natural gas). Intelligent control based on using different strategies (not only stabilization), prediction and consideration of natural disturbances on biotechnical objects, physiological features of biological objects (poultry, plants etc.) allows to reduce energy consumption. The paper presents specific knowledge concerning promising areas of control systems of biotechnical objects, methodological bases for specialized algorithmic-mathematical software construction based on the methods of game theory and statistical solutions, neural networks (including genetic algorithm), filtering the noise components of information signals
Управління ризиками інфокомунікаційної мережі при стратегічному плануванні безпеки систем критичної інраструктури
The subject matter of the article is information and communication networks of critical infrastructure systems. The goal of the work is to create an approach for strategic managing the security of critical infrastructure systems taking into account the risks of the information and communication network. The article deals with the following tasks: determining the procedure of strategic managing the security of critical infrastructure systems, identifying the risks of the information and communication network, assessing the importance and probability of partial network risks. The following methods are used: a systematic approach, cause-and-effect analysis, statistical methods. The following results are obtained: the diagram of multi-level risk management of critical infrastructure systems is developed; the diagram of the step-by-step method of information risks management is developed for increasing the safety of the system; the complex index is suggested for determining the category of information system security; probable variants of the full-factor environment of a set of values of the complex index elements and the corresponding categories of information systems security are analyzed; the process of adaptation of the system as an integral part of the selection and specification of measures for the risk reduction of the information and communication network is determined; the example of the risk assessment of the information and communication network for a software and hardware complex in the automated control system of technological processes is considered. Taking into account the categories of factors, a list of probable risks of the information and communication network and factors that cause them is given; the cause-and-effect diagram of "cause-risk-effect" interaction is created; the total effect of each factor on the final vertices of the diagram, that is possible effects, is calculated; the factors were grouped as the most important, quite important, of mean importance, and inconsiderable ones.Предметом дослідження в статті є інфокомунікаційні мережі систем критичної інфраструктури. Мета роботи – створення підходу для стратегічного управління безпекою систем критичної інфраструктури з урахуванням ризиків інфокомунікаційної мережі. В статті вирішуються наступні завдання: визначення процедури стратегічного управління безпекою систем критичної інфраструктури, ідентифікація ризиків інфокомунікаційної мережі, оцінка важливості та ймовірності часткових ризиків мережі. Використовуються такі методи: системний підхід, причинно-наслідковий аналіз, статистичні методи. Отримано наступні результати: Побудовано схему багаторівневого управління ризиками систем критичної інфраструктури. Розроблено схему покрокового методу управління інформаційними ризиками для підвищення безпеки системи. Запропоновано комплексний показник для визначення категорії безпеки інформаційної системи. Проаналізовано можливі варіанти повного факторного простору множини значень елементів комплексного показника і відповідні їм категорії безпеки інформаційних систем. Визначено процес адаптації системи як невід'ємну частину вибору і специфікації заходів щодо парирування ризиків інфокомунікаційної мережі. Розглянуто приклад оцінки ризику інфокомунікаційної мережі для програмно-технічного комплексу у складі автоматизованої системи управління технологічними процесами. З урахуванням категорій факторів наведено перелік можливих ризиків інфокомунікаційної мережі із зазначенням причин їх виникнення. Побудовано причинно-наслідкову діаграму взаємодії "причини-ризики-наслідки". Розраховано загальний вплив кожного фактора на кінцеві вершини діаграми – можливі наслідки. Було класифіковано фактори на чотири групи: найбільш важливі, досить значні, середньої значущості, незначні
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