Design-time performance analysis of component-based real-time systems

In current real-time systems, performance metrics are one of the most challenging properties to specify, predict and measure. Performance properties depend on various factors, like environmental context, load profile, middleware, operating system, hardware platform and sharing of internal resources. Performance failures and not satisfying related requirements cause delays, cost overruns, and even abandonment of projects. In order to avoid these performancerelated project failures, the performance properties should be obtained and analyzed already at the early design phase of a project. In this thesis we employ principles of component-based software engineering (CBSE), which enable building software systems from individual components. The advantage of CBSE is that individual components can be modeled, reused and traded. The main objective of this thesis is to develop a method that enables to predict the performance properties of a system, based on the performance properties of the involved individual components. The prediction method serves rapid prototyping and performance analysis of the architecture or related alternatives, without performing the usual testing and implementation stages. The involved research questions are as follows. How should the behaviour and performance properties of individual components be specified in order to enable automated composition of these properties into an analyzable model of a complete system? How to synthesize the models of individual components into a model of a complete system in an automated way, such that the resulting system model can be analyzed against the performance properties? The thesis presents a new framework called DeepCompass, which realizes the concept of predictable assembly throughout all phases of the system design. The cornerstones of the framework are the composable models of individual software components and hardware blocks. The models are specified at the component development time and shipped in a component package. At the component composition phase, the models of the constituent components are synthesized into an executable system model. Since the thesis focuses on performance properties, we introduce performance-related types of component models, such as behaviour, performance and resource models. The dynamics of the system execution are captured in scenario models. The essential advantage of the introduced models is that, through the behaviour of individual components and scenario models, the behaviour of the complete system is synthesized in the executable system model. Further simulation-based analysis of the obtained executable system model provides application-specific and system-specific performance property values. To support the performance analysis, we have developed a CARAT software toolkit that provides and automates the algorithms for model synthesis and simulation. Besides this, the toolkit provides graphical tools for designing alternative architectures and visualization of obtained performance properties. We have conducted an empirical case study on the use of scenarios in the industry to analyze the system performance at the early design phase. It was found that industrial architects make extensive use of scenarios for performance evaluation. Based on the inputs of the architects, we have provided a set of guidelines for identification and use of performance-critical scenarios. At the end of this thesis, we have validated the DeepCompass framework by performing three case studies on performance prediction of real-time systems: an MPEG-4 video decoder, a Car Radio Navigation system and a JPEG application. For each case study, we have constructed models of the individual components, defined the SW/HW architecture, and used the CARAT toolkit to synthesize and simulate the executable system model. The simulation provided the predicted performance properties, which we later compared with the actual performance properties of the realized systems. With respect to resource usage properties and average task latencies, the variation of the prediction error showed to be within 30% of the actual performance. Concerning the pick loads on the processor nodes, the actual values were sometimes three times larger than the predicted values. As a conclusion, the framework has proven to be effective in rapid architecture prototyping and performance analysis of a complete system. This is valid, as in the case studies we have spent not more than 4-5 days on the average for the complete iteration cycle, including the design of several architecture alternatives. The framework can handle different architectural styles, which makes it widely applicable. A conceptual limitation of the framework is that it assumes that the models of individual components are already available at the design phase

Crystal Phases of Charged Interlayer Excitons in van der Waals Heterostructures

Throughout the years, strongly correlated coherent states of excitons have been the subject of intense theoretical and experimental studies. This topic has recently boomed due to new emerging quantum materials such as van der Waals (vdW) bound atomically thin layers of transition metal dichalcogenides (TMDs). We analyze the collective properties of charged interlayer excitons observed recently in bilayer TMD heterostructures. We predict new strongly correlated phases - crystal and Wigner crystal - that can be selectively realized with TMD bilayers of properly chosen electron-hole effective masses by just varying their interlayer separation distance. Our results open up new avenues for nonlinear coherent control, charge transport and spinoptronics applications with quantum vdW heterostuctures.Comment: 34 pages, 8 figures, 57 reference

THE PROCEDURES OF VISUAL ANALYSIS FOR MULTIDIMENSIONAL DATA VOLUMES

The paper is devoted to problems of visual analysis of multidimensional data sets using an approach based on the construction of elastic maps. This approach is quite suitable for processing and visualizing of multidimensional datasets. The elastic maps are used as the methods of original data points mapping to enclosed manifolds having less dimensionality. Diminishing the elasticity parameters one can design map surface which approximates the multidimensional dataset in question much better. Then the points of dataset in question are projected to the map. The extension of designed map to a flat plane allows one to get an insight about the structure of multidimensional dataset. The paper presents the results of applying elastic maps for visual analysis of multidimensional data sets of medical origin. Previously developed data processing procedures are applied to improve the results obtained - pre-filtering of data, removal of separated clusters (flotation), quasi-Zoom

Фригопротекторні та антиоксидантні властивості препаратів глюкозаміну та ацетилсаліцилової кислоти в умовах гострої локальної холодової травми

Topicality. Cold trauma (HT) is a common factor of the environmental impact on human body. They are found in all parts of our planet and in the structure of peacetime trauma are from 3 to 10 %, accompanied by significant disability of victims and mortality. Acute exposure to cold leads to increasing of free radicals formation, contributes to antioxidant system depletion (AOS) and activates lipid peroxidation (LPO).Aim. To study the effect of glucosamine and acetylsalicylic acid (ASA) preparations on the course of experimental pathology (the state of the affected area of the skin, body temperature, body mass dynamics), the intensity of LPO and the state of AOS under conditions of model acute local CT (frostbite).Materials and methods. As the frigoprotectors are selected G h/ch (Sigma-Aldrich, USA), “Glucosamine-S BHFZ” and the drug ASK (“Darnitsa”, Kiev). After a local CT, the rectal temperature, skin lesions, LPO and AOS in the blood serum were measured.Results and discussion. G h/ch exhibits a more pronounced frigoprotective effect with local acute CT in terms of: skin lesions, restoration of rectal temperature and body weight, antioxidant effect, superior to ASA and Glucosamine-C BHPF.Conclusions. The antioxidant properties of G h/ch, “Glucosamine-C BHFZ” and to a lesser extent ASA, which were detected in acute general cooling, are confirmed in this work under local CT conditions. These results substantiate the expediency of using these agents, primarily glucosamine, in the treatment of local cold trauma.Актуальность. Холодовые травмы (ХТ) являются распространенным фактором влияния окружающей среды на организм человека. Они встречаются во всех частях нашей планеты и в структуре травм мирного времени составляют от 3 до 10 %, сопровождаются значительной инвалидизацией пострадавших и летальностью. Острое воздействие холода приводит к повышенному образованию свободных радикалов, способствует истощению антиоксидантной системы (АОС) и активирует перекисное окисление липидов (ПОЛ).Цель исследования. Изучить влияние препаратов глюкозамина и ацетилсалициловой кислоты (АСК) на течение экспериментальной патологии (состояние пораженного участка кожи, температуру тела, динамикумассы тела), интенсивность ПОЛ и состояние АОС в условиях модельной острой локальной ХТ (отморожения).                                                  Материалы и методы. Как фригопротекторы выбраны Г г/х (Sigma-Aldrich, USA), «Глюкозамин-С БХФЗ» и препарат АСК («Дарница», Киев). После локальной холодовой травмы (ХТ) измеряли ректальную температуру, площадь поражений кожи, ПОЛ и АОС в сыворотке крови.                          Результаты и их обсуждение. Г г/х проявляет более выраженное фригопротекторное действие при локальной острой ХТ по показателям: площади поражения кожи, восстановления ректальной температуры и массы тела, антиоксидантного действия, превосходя АСК и «Глюкозамин-С БХФЗ». Выводы. Антиоксидантные свойства Г г/х, «Глюкозамина-С БХФЗ» и в меньшей степени АСК, которые выявлены при остром общем охлаждении, подтверждены в данной работе в условиях локальной ХТ. Эти результаты экспериментально обосновывают целесообразность использования указанных средств, прежде всего содержащих глюкозамин, в лечении локальных ХТ.Актуальність. Холодові травми (ХТ) є поширеним фактором впливу довкілля на організм людини. Вони зустрічаються у всіх частинах нашої планети та в структурі травм мирного часу складають від 3 до 10 %, супроводжуються значною інвалідизацією потерпілих та летальністю. Гостра дія холоду призводить до підвищеного утворення вільних радикалів, спричиняє виснаження антиоксидантної системи (АОС) та активує пероксидне окиснення ліпідів (ПОЛ).Мета дослідження. З’ясувати вплив препаратів глюкозаміну та ацетилсаліцилової кислоти (АСК) на перебіг експериментальної патології (стан ураженої ділянки шкіри, температура тіла, динаміка маси тіла), інтенсивність ПОЛ і стан АОС в умовах модельної гострої локальної ХТ (відмороження).Матеріали та методи. Як фригопротектори обрано Г г/х (Sigma-Aldrich, USA), «Глюкозамін-С БХФЗ» та препарат АСК («Дарниця», Київ). Після локальної холодової травми (ХТ) вимірювали ректальну температуру, площу уражень шкіри, ПОЛ та АОС у сироватці крові.Результати та їх обговорення. Г г/х виявляє більш виразну фригопротекторну дію при локальній гострій ХТ за показниками площі ураження шкіри, відновлення ректальної температури та маси тіла, антиоксидантної дії, перевишуючи АСК та «Глюкозамін-С БХФЗ».Висновки. Антиоксидантні властивості Г г/х, «Глюкозаміну-С БХФЗ» та меншою мірою АСК, що їх виявлено при гострому загальному охолодженні, підтверджені у даній роботі в умовах локальної ХТ. Ці результати експериментально обґрунтовують доцільність використання зазначених засобів, перш за все тих, що містять глюкозамін, у лікуванні локальних холодових травм

Triboelectric Backgrounds to radio-based UHE Neutrino Exeperiments

The triboelectric effect broadly includes any process in which force applied at a boundary layer results in displacement of surface charge, leading to the generation of an electrostatic potential. Wind blowing over granular surfaces, such as snow, can induce a potential difference, with subsequent coronal discharge. Nanosecond timescale discharges can lead to radio-frequency emissions with characteristics similar to piezoelectric-induced discharges. For Antarctic-sited experiments seeking detection of radio-frequency signals generated by collisions of cosmic rays or neutrinos with atmospheric or englacial molecular targets, triboelectric emissions from the surface pose a potential background. This is particularly true for experiments in which radio antennas are buried ~(1--100) m below the snow surface, and seeking to validate neutrino detection strategies by measurement of down-coming radio-frequency emissions from extensive air showers. Herein, after summarizing extant evidence for wind-induced triboelectric effects previously reported elsewhere, we detail additional analysis using archival data collected with the RICE and AURA experiments at the South Pole. We broadly characterize those radio-frequency emissions based on source location, and time-domain and also frequency-domain characteristics. We find that: a) For wind velocities in excess of 10-12 m/s, triboelectric background triggers can dominate data-taking, b) frequency spectra for triboelectric events are generally shifted to the low-end of the regime to which current radio experiments are typically sensitive (100-200 MHz), c) there is an apparent preference for tribo-electric discharges from metal surface structures, consistent with a model in which localized, above-surface structures provide a repository for transported charge

Photon Bose-Condensate as a Tunable Terahertz Laser Source without Inversion

We develop a theoretical model for a tunable coherent terahertz radiation source based on the long-lived Bose condensate of photons. In the device we propose, the original photon pumping is performed incoherently by a blackbody radiation emitter. The photons thus produced Bose-condense by the inelastic relaxation on a two-dimensional electron gas in a perpendicular magnetostatic field. The process involves neither population inversion nor light wave amplification the standard laser sources are built on. The coherence and tunability of the light emitted by such a photon condensate are provided and supported by the discrete spectrum of the electron gas in the quantizing magnetic field. The device is a compact-size semiconductor crystal. We propose the design and perform the realistic calculations of the physical properties and limiting factors for the terahertz photon Bose-condensate resonator. We show that our terahertz source can deliver the highly coherent light emission in the frequency range of 3-30 THz for the magnetic field induction of the order of 2 T, with the upper emission frequency limit adjustable by the strength of the magnetic field applied.Comment: Main text (15 pages, 7 figures, 52 references) + Supplementary materials (27 pages, 27 figures, 10 references