Модемное оборудование на основе SDR-технологии для тропосферных станций нового поколения

Проблематика. Модемне обладнання тропосферних ліній зв’язку є важливим компонентом сучасних засобів телекомунікації. Дослідження теоретичних і практичних аспектів вибору кращого варіанту модемного обладнання з урахуванням сукупних показників якості залишається актуальним. Мета досліджень. Представлення особливостей створення модемного обладнання тропосферних станцій нового покоління, які можуть забезпечувати високі швидкості передачі даних з гарантованою якістю обслуговування в складних умовах стаціонарних і нестаціонарних завад, які властиві тропосферним каналам зв’язку. Методика реалізації. Поставлена мета досягається за рахунок використання нових технічних і архітектурних рішень щодо створення модемного обладнання на основі технології SDR, спектрально ефективних видів модуляції та кодування, алгоритмів ефективної адаптації до постійно змінюваних умов експлуатації. Можливість реалізації запропонованих підходів до побудови модемного обладнання виконується на прототипі обладнання, створеному на базі налагоджувальних модулів HSMC. Результати досліджень. Представлено особливості побудови модемного обладнання тропосферної станції з високою швидкістю передачі даних. Для досягнення граничних параметрів таких станцій запропоновано застосування в модемному обладнанні нових технічних і архітектурних рішень, спектрально-ефективних видів модуляції (OFDM плюс лінійна модуляція) і завадостійкого кодування, ефективних алгоритмів адаптації до постійно змінюваних умов роботи, технології SDR, структур кадрів фізичного рівня. Запропоновано варіанти конфігурації модемного обладнання стосовно режимів роботи малогабаритної тропосферної станції. Висновки. Запропоновані підходи до підвищення ефективності модемного обладнання дають змогу реалізувати компактні тропосферні радіорелейні станції з високою швидкістю передачі інформації.Background. Modem equipment of tropospheric communication lines is an important component of modern means of telecommunication. The theoretical and practical aspects of choosing a preferred embodiment of modem equipment, taking into account the aggregate indicators of quality. Objective. Presentation of features of the modem equipment construction of new generation tropospheric stations that can provide high data transfer rates with guaranteed quality of service in complex stationary and non-stationary noise inherent in tropospheric channels. Methods. The goal is achieved by using new technical and architectural solutions to build SDR based modem equipment, spectrally efficient modulation types and coding, algorithms of effective adaptation to changing operating conditions. Feasibility of the proposed approaches to the construction of the modem hardware is fulfilled on a prototype of the equipment based on the HSMC ARRadio Daughter Card debugging modules. Results. The features of constructing of modem equipment of troposcatter stations with high data transfer rate are provided. To reach the limiting parameters of such stations the application of modem equipment of new technical and architectural solutions, spectrally efficient modulation types (OFDM plus linear modulation) and error-correcting coding, efficient algorithms of adaptation to changing conditions of work, the SDR technology, frame structures of physical layer was proposed. The configuration variants of modem equipment in relation to the modes of operation of compact troposcatter station were proposed. Conclusions. The proposed ways to improve the effectiveness of modem equipment allow realizing compact troposcatter radiorelay stations with a high rate of data transmission.Проблематика. Модемное оборудование тропосферных линий связи является важным компонентом современных средств связи. Исследование теоретических и практических аспектов выбора лучшего варианта модемного оборудования с учетом совокупных показателей качества остается актуальным. Цель исследований. Представление особенностей создания модемного оборудования тропосферных станций нового поколения, которые могут обеспечивать высокие скорости передачи данных с гарантированным качеством обслуживания в сложных условиях стационарных и нестационарных помех, присущих тропосферным каналам связи. Методика реализации. Поставленная цель достигается за счет использования новых технических и архитектурных решений при создании модемного оборудования на основе технологии SDR, спектрально эффективных видов модуляции и кодирования, алгоритмов эффективной адаптации к изменяющимся условиям эксплуатации. Возможность реализации предложенных подходов к построению модемного оборудования была показана на прототипе оборудования, который был создан на базе отладочных модулей HSMC. Результаты исследований. Представлены особенности построения модемного оборудования тропосферной станции с высокой скоростью передачи данных. Для достижения предельных параметров таких станций предложено применение в модемном оборудовании новых технических и архитектурных решений, спектрально-эффективных видов модуляции (OFDM плюс линейная модуляция) и помехоустойчивого кодирования, эффективных алгоритмов адаптации к изменяющимся условиям работы, технологии SDR, структуры кадров физического уровня. Предложены варианты конфигурации модемного оборудования по отношению к режимам работы малогабаритной тропосферной станции. Выводы. Предложенные подходы к повышению эффективности модемного оборудования позволяют реализовать компактные тропосферные радиорелейные станции с высокой скоростью передачи информации

Specific Structural and Logical Model of Emergency Management

The work is devoted to solving one of the specific aspects of managing terrorist emergencies – an urgent scientific problem of our time. To achieve this goal, the work initially provides an analysis of the stages of development of emergency situations. It is shown that emergencies are objective (existing regardless of the attitude towards them) spatio-temporal processes, each of which is conventionally divided into five stages, namely: everyday accumulation of negative factors; extreme development of a negative factor; catastrophic event; elimination of the consequences of this event and their remote consequences. They occur in vehicles, man-made and natural objects, areas of the territory, water basins and mountains, cities and administrative regions. The type of each emergency is tied to a certain catastrophic event that can happen, is happening or has already happened. Then a prototype is considered - a typical structural - logical model of emergency management, which consists of six blocks. This is monitoring the situation (collecting everyday factors), identifying risk (detecting an extreme factor), analyzing risk (forecasting and modeling an emergency), preparing options for management decisions, making a decision and communicating it to executors. The subsequent impact on the situation (control object), through the structure of performers, closes the control loop, providing a continuous control process in the interests of preventing catastrophic events. On the basis of the prototype, a specific structural and logical model for managing an emergency of a terrorist nature caused by the detection of a small explosive device has been developed. It consists of thirteen blocks. This is situation monitoring, risk identification, warning and evacuation of people, search and identification of an explosive device, an explosive device, a dummy, a safe object, making a decision to use a special dome, preparatory measures, neutralizing an explosive device, localizing the consequences of neutralization, making a decision to resume and the work of the object, the impact on the situation. The location of the blocks at ten hierarchical levels, connected by logical links, provides the collection of information about the state of the object of a mass gathering of people through the elements of the monitoring system and impact on the object through the system of executors, providing a continuous management process in the interests of minimizing the consequences of terrorist events

Adsorption of Nitrogen-Containing Compounds on the (100) α‑Quartz Surface: Ab Initio Cluster Approach

A cluster approach extended to the ONIOM methodology has been applied using several density functionals and Møller–Plesset perturbation theory (MP2) to simulate the adsorption of selected nitrogen-containing compounds [NCCs, 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT), 2,4-dinitroanisole (DNAN), and 3-nitro-1,2,4-triazole-5-one (NTO)] on the hydroxyated (100) surface of α-quartz. The structural properties were calculated using the M06-2X functional and 6-31G­(d,p) basis set. The M06-2X-D3, PBE-D3, and MP2 methods were used to calculate the adsorption energies. Results have been compared with the data from other studies of adsorption of compounds of similar nature on silica. Effect of deformation of the silica surface and adsorbates on the binding energy values was also studied. The atoms in molecules (AIM) analysis was employed to characterize the adsorbate–adsorbent binding and to calculate the bond energies. The silica surface shows different sorption affinity toward the chemicals considered depending on their electronic structure. All target NCCs are physisorbed on the modeled silica surface. Adsorption occurs due to the formation of multiple hydrogen bonds between the functional groups of NCCs and surface silanol groups. Parallel orientation of NCCs interacting with the silica surface was found to be favorable when compared with perpendicularly oriented NCCs. NTO was found to be the most strongly adsorbed on the silica surface among all of the considered compounds. Dispersion correction was shown to play an important role in the DFT calculations of the adsorption energies of silica–NCC systems

A new mechanism of post-transfer editing by aminoacyl-tRNA synthetases: catalysis of hydrolytic reaction by bacterial-type prolyl-tRNA synthetase

<p>Aminoacyl tRNA synthetases are enzymes that specifically attach amino acids to cognate tRNAs for use in the ribosomal stage of translation. For many aminoacyl tRNA synthetases, the required level of amino acid specificity is achieved either by specific hydrolysis of misactivated aminoacyl-adenylate intermediate (pre-transfer editing) or by hydrolysis of the mischarged aminoacyl-tRNA (post-transfer editing). To investigate the mechanism of post-transfer editing of alanine by prolyl-tRNA synthetase from the pathogenic bacteria <i>Enterococcus faecalis</i>, we used molecular modeling, molecular dynamic simulations, quantum mechanical (QM) calculations, site-directed mutagenesis of the enzyme, and tRNA modification. The results support a new tRNA-assisted mechanism of hydrolysis of misacylated Ala-tRNA^Pro. The most important functional element of this catalytic mechanism is the 2′-OH group of the terminal adenosine 76 of Ala-tRNA^Pro, which forms an intramolecular hydrogen bond with the carbonyl group of the alanine residue, strongly facilitating hydrolysis. Hydrolysis was shown by QM methods to proceed via a general acid-base catalysis mechanism involving two functionally distinct water molecules. The transition state of the reaction was identified. Amino acid residues of the editing active site participate in the coordination of substrate and both attacking and assisting water molecules, performing the proton transfer to the 3′-O atom of A76.</p

Measurement of the W+bW+b-jet and W+cW+c-jet differential production cross sections in ppˉp\bar{p} collisions at s=1.96\sqrt{s}=1.96 TeV

We present a measurement of the cross sections for the associated production of a $W$ boson with at least one heavy quark jet, $b$ or $c$, in proton-antiproton collisions. Data corresponding to an integrated luminosity of 8.7 fb$^{-1}$ recorded with the D0 detector at the Fermilab Tevatron \ppbar Collider at $\sqrt{s}=1.96$ TeV are used to measure the cross sections differentially as a function of the jet transverse momenta in the range 20 to 150 GeV. These results are compared to calculations of perturbative QCD theory as well as predictions from Monte Carlo generators.We present a measurement of the cross sections for the associated production of a $W$ boson with at least one heavy quark jet, $b$ or $c$, in proton-antiproton collisions. Data corresponding to an integrated luminosity of 8.7 fb$^{-1}$ recorded with the D0 detector at the Fermilab Tevatron \ppbar Collider at $\sqrt{s}=1.96$ TeV are used to measure the cross sections differentially as a function of the jet transverse momenta in the range 20 to 150 GeV. These results are compared to calculations of perturbative QCD theory as well as predictions from Monte Carlo generators.We present a measurement of the cross sections for the associated production of a W boson with at least one heavy quark jet, b or c , in proton–antiproton collisions. Data corresponding to an integrated luminosity of 8.7 fb−1 recorded with the D0 detector at the Fermilab Tevatron pp¯ Collider at s=1.96 TeV are used to measure the cross sections differentially as a function of the jet transverse momenta in the range 20 to 150 GeV. These results are compared to calculations of perturbative QCD theory as well as predictions from Monte Carlo generators