Spatio-temporal dynamics of quantum-well excitons

We investigate the lateral transport of excitons in ZnSe quantum wells by using time-resolved micro-photoluminescence enhanced by the introduction of a solid immersion lens. The spatial and temporal resolutions are 200 nm and 5 ps, respectively. Strong deviation from classical diffusion is observed up to 400 ps. This feature is attributed to the hot-exciton effects, consistent with previous experiments under cw excitation. The coupled transport-relaxation process of hot excitons is modelled by Monte Carlo simulation. We prove that two basic assumptions typically accepted in photoluminescence investigations on excitonic transport, namely (i) the classical diffusion model as well as (ii) the equivalence between the temporal and spatial evolution of the exciton population and of the measured photoluminescence, are not valid for low-temperature experiments.Comment: 8 pages, 6 figure

A machine learning approach for feature selection traffic classification using security analysis

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Class imbalance has become a big problem that leads to inaccurate traffic classification. Accurate traffic classification of traffic flows helps us in security monitoring, IP management, intrusion detection, etc. To address the traffic classification problem, in literature, machine learning (ML) approaches are widely used. Therefore, in this paper, we also proposed an ML-based hybrid feature selection algorithm named WMI_AUC that make use of two metrics: weighted mutual information (WMI) metric and area under ROC curve (AUC). These metrics select effective features from a traffic flow. However, in order to select robust features from the selected features, we proposed robust features selection algorithm. The proposed approach increases the accuracy of ML classifiers and helps in detecting malicious traffic. We evaluate our work using 11 well-known ML classifiers on the different network environment traces datasets. Experimental results showed that our algorithms achieve more than 95% flow accuracy results

Optical microscopy in the nano-world

Scanning near-field optical microscopy (SNOM) is an optical microscopy whose resolution is not bound to the diffraction limit. It provides chemical information based upon spectral, polarization and/or fluorescence contrast images. Details as small as 20 nm can be recognized. Photophysical and photochemical effects can be studied with SNOM on a similar scale. This article reviews a good deal of the experimental and theoretical work on SNOM in Switzerland

Computational Treatment of Metalloproteins

Metalloproteins present a considerable challenge for modeling, especially when the starting point is far from thermodynamic equilibrium. Examples include formidable problems such as metalloprotein folding and structure prediction upon metal addition, removal, or even just replacement; metalloenzyme design, where stabilization of a transition state of the catalyzed reaction in the specific binding pocket around the metal needs to be achieved; docking to metal-containing sites and design of metalloenzyme inhibitors. Even more conservative computations, such as elucidations of the mechanisms and energetics of the reaction catalyzed by natural metalloenzymes, are often nontrivial. The reason is the vast span of time and length scales over which these proteins operate, and thus the resultant difficulties in estimating their energies and free energies. It is required to perform extensive sampling, properly treat the electronic structure of the bound metal or metals, and seamlessly merge the required techniques to assess energies and entropies, or their changes, for the entire system. Additionally, the machinery needs to be computationally affordable. Although a great advancement has been made over the years, including some of the seminal works resulting in the 2013 Nobel Prize in chemistry, many aforementioned exciting applications remain far from reach. We review the methodology on the forefront of the field, including several promising methods developed in our lab that bring us closer to the desired modern goals. We further highlight their performance by a few examples of applications

Diagnosis and management of Cornelia de Lange syndrome:first international consensus statement

Cornelia de Lange syndrome (CdLS) is an archetypical genetic syndrome that is characterized by intellectual disability, well-defined facial features, upper limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in any one of seven genes, all of which have a structural or regulatory function in the cohesin complex. Although recent advances in next-generation sequencing have improved molecular diagnostics, marked heterogeneity exists in clinical and molecular diagnostic approaches and care practices worldwide. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria, both for classic CdLS and non-classic CdLS phenotypes, molecular investigations, long-term management and care planning

ДОСЛІДЖЕННЯ ГРАНИЧНИХ ЧАСОВИХ ПОКАЗНИКІВ ПРОГРАМНИХ СЕРЕДОВИЩ ОПЕРАЦІЙНИХ СИСТЕМ РЕАЛЬНОГО ЧАСУ

Purpose. More than 20 years of the Worst Case Execution Time (WCET) studies have led to the development of many methods for its evaluation. So far, there are no definitive conclusions about usage of these methods. Therefore, the purpose of this paper is to determine the possibility of using a hybrid method for estimating WCET in real-time systems. Methodology. The approach for evaluating WCET for a hybrid method is to parse the input code in the C++ programming language and, after constructing the control flow graph, get the execution time of its base blocks. After finding the longest way of the graph, to estimate the time of execution of this way and get the WCET evaluation. To find the longest-running way, the reverse Dijkstra algorithm was chosen. After that, there was made a comparison of the limiting time estimations that were obtained by static and hybrid methods, as well as an analysis of the discrepancy between these results. Findings. Determining the worst execution time of programs is most important for "hard real-time" tasks. Underestimation of this indicator can lead to catastrophic consequences. An overestimation – to a significant overexpenditure of resources. Therefore, WCET was evaluated using static and dynamic methods. It was determined that the results obtained by the two methods correlate well. For the class of tasks that are under consideration, WCET execution time can be determined using a hybrid method. Adding an extra time of 15–20 % to the results, obtained by the hybrid method, allows getting a foolproof estimate of WCET in real-time systems. Originality. The hybrid method has been existing for some time, but the reliability of its use has not been sufficiently studied yet. The given study makes a step in determining the practical applicability of the hybrid method for time estimation of real-time tasks. Practical value. The results of this research allow us to conclude that a hybrid method could be used for obtaining WCET in "hard real-time" tasks. Furthermore, some unknown at this moment influence of the OS RT environment can be taken into account by adding extra time.Цель. Более чем двадцатилетний срок исследования оценки наихудшего времени выполнения программ (Worst Case Execution Time, WCET) привел к разработке многих методов. До сих пор нет окончательных выводов относительно применения того или иного метода. Поэтому целью нашей работы является определение возможности использования гибридного метода для оценки WCET в системах реального времени. Методика. Выяснение оценки WCET для гибридного метода заключается в том, чтобы провести  синтаксический анализ на языке программирования С++ и, построив граф потока управления, получить время выполнения его базовых блоков. Найдя самый длинный путь графа, оценить время выполнения этого пути и получить оценку WCET. Для поиска самого длинного по времени выполнения пути был выбран обратный алгоритм Дейкстры. После чего было выполнено сравнение предельных временных оценок, полученных статическим и гибридным методами, а также анализ расхождения этих результатов. Результаты. Определение худшего времени выполнения программ наиболее важно для задач «жесткого реального времени». Недооценка этого показателя может привести к катастрофическим последствиям. А переоценка – к существенному перерасходу ресурсов. Поэтому была проведена оценка WCET с помощью статического и динамического методов, которая дала возможность определить, что результаты, полученные двумя методами, неплохо коррелируют. Для рассматриваемого класса задач время выполнения WCET может быть определено с помощью гибридного метода. Добавление дополнительного времени в размере 15–20 % к результатам, полученным гибридным методом, позволяет получить безопасную оценку WCET в системах реального времени. Научная новизна. Гибридный метод существует уже некоторое время, но надежность его использования еще не была достаточно изучена. Данное исследование делает шаг в определении практической применимости гибридного метода для временной оценки задач реального времени. Практическая значимость. Результаты исследования позволяют сделать выводы, что гибридный метод может быть использован для получения WCET в задачах «жесткого реального времени». А некоторое неизвестное на данный момент влияние среды операционных систем реального времени (ОС РВ) может быть учтено добавлением дополнительного времени.Мета. Більш ніж двадцятирічний термін дослідження оцінки найгіршого часу виконання програм (Worst Case Execution Time, WCET) призвів до розробки багатьох методів. До цього часу немає остаточних висновків щодо застосування того чи іншого методу. Тому метою нашої роботи є визначення можливості використання гібридного методу для оцінки WCET у системах реального часу. Методика. З’ясування оцінки WCET для гібридного методу полягає в тому, щоб провести синтаксичний аналіз вхідного коду мовою програмування С++ та, побудувавши граф потоку керування, отримати час виконання його базових блоків. Знайшовши найдовший шлях графа, оцінити час виконання цього шляху й отримати оцінку WCET. Для пошуку найдовшого за часом виконання шляху був обраний зворотний алгоритм Дейкстри. Після чого було виконане порівняння граничних часових оцінок, отриманих статичним і гібридним методами, а також аналіз розбіжності цих результатів. Результати. Визначення найгіршого часу виконання програм найбільш важливе для задач «жорсткого реального часу». Недооцінка цього показника може призвести до катастрофічних наслідків. А переоцінка – до суттєвої перевитрати ресурсів. Тому була проведена оцінка WCET за допомогою статичного й динамічного методів, яка дає змогу визначити, що результати, отримані двома методами, непогано корелюються. Для розглянутого класу задач час виконання WCET може бути визначений за допомогою гібридного методу. Додавання додаткового часу в розмірі 15–20 % до результатів, отриманих гібридним методом, дозволяє отримати безпечну оцінку WCET у системах реального часу. Наукова новизна. Гібридний метод існує вже певний час, але надійність його використання ще не була достатньо вивчена. Дане дослідження робить крок у визначенні практичної застосованості гібридного методу для часової оцінки задач реального часу. Практична значимість. Результати дослідження дозволяють дійти висновків, що гібридний метод може бути використаний для отримання оцінки WCET у задачах «жорсткого реального часу». А деякий невідомий на даний момент вплив середовища операційної системи реального часу (ОС РЧ) може бути врахований додаванням додаткового часу

RESEARCH OF LIMIT TIME INDICES OF SOFTWARE ENVIRONMENTS OF REAL TIME OPERATING SYSTEMS

Purpose. More than 20 years of the Worst Case Execution Time (WCET) studies have led to the development of many methods for its evaluation. So far, there are no definitive conclusions about usage of these methods. Therefore, the purpose of this paper is to determine the possibility of using a hybrid method for estimating WCET in real-time systems. Methodology. The approach for evaluating WCET for a hybrid method is to parse the input code in the C++ programming language and, after constructing the control flow graph, get the execution time of its base blocks. After finding the longest way of the graph, to estimate the time of execution of this way and get the WCET evaluation. To find the longest-running way, the reverse Dijkstra algorithm was chosen. After that, there was made a comparison of the limiting time estimations that were obtained by static and hybrid methods, as well as an analysis of the discrepancy between these results. Findings. Determining the worst execution time of programs is most important for "hard real-time" tasks. Underestimation of this indicator can lead to catastrophic consequences. An overestimation – to a significant overexpenditure of resources. Therefore, WCET was evaluated using static and dynamic methods. It was determined that the results obtained by the two methods correlate well. For the class of tasks that are under consideration, WCET execution time can be determined using a hybrid method. Adding an extra time of 15–20 % to the results, obtained by the hybrid method, allows getting a foolproof estimate of WCET in real-time systems. Originality. The hybrid method has been existing for some time, but the reliability of its use has not been sufficiently studied yet. The given study makes a step in determining the practical applicability of the hybrid method for time estimation of real-time tasks. Practical value. The results of this research allow us to conclude that a hybrid method could be used for obtaining WCET in "hard real-time" tasks. Furthermore, some unknown at this moment influence of the OS RT environment can be taken into account by adding extra time

EFFICACY OF THE USE OF REMNANT STOMACH IN ESOPHAGOPLASTY

In the period from 2001 till 2010 there were 117 extirpations of the oesophagus with single-stage plasty of the stomach in 94 patients and plasty of the large intestine - in 23 cases. Gastric resections were performed earlier in 50 (42,7%) patients, though gastrectomy took place in 39 (78%) patients. The accumulated experience allowed making an assessment of immediate and long-term results of esophagoplasty to patients, who had earlier the gastric resection. The incompetence of oesophagogastric anastomosis was noted in 2 times more frequent and the formation of stenosis of given anastomosis in 3 times more often. I order to improve the results of esophagoplasty, the method of serousmyotomy was applied in the cases of remnant stomach