77 research outputs found
High-Speed Natural Selection in Financial Markets with Large State Spaces
No full textRecent research has suggested that natural selection in financial markets may be a very slow process, taking hundreds of years. We show in a general equilibrium model that it may be much faster in markets with large state spaces. In many cases, the time it takes to wipe out irrational investors is inversely proportional to the number of stocks in the market, i.e., if it takes about 500 years with one stock, it takes about one year with 500 stocks. Thus, theoretically, natural selection can be very efficient even when there is high market uncertainty. The speed of the natural selection process is a known function of irrational investors' sentiment and of the real characteristics of the stock market. According to a calibration to U.S. stock data, it takes about fifty years for an irrational investor to be wiped out. This is in line with studies of individual investor underperformance.Asset pricing; Market selection hypothesis; Natural selection
THE AGE OF PHILOSOPHY IS COMING
No full textYury Simonov-Viazemsky (Yu. S.-V.), the writer, the author and producer of Russian Teleolympiade «Umnicky i Umnitzy» (Wise and Clever), Honoured Cultural Worker of Russia, the head of the Department of World Literature and Culture of MGIMO, the editor-in-chief of the Journal "Concept: Philosophy, Religion, Culture" is interviewed by MGIMO Professor, Doctor of Philosophy Margarita Silantieva (M.S.) and Ph.D. student Daria Liubinsky (D.L.)
Thwarted Action Needed -- Informational Theories of Emotions
No full textThe Russian psychologist L. Vygotsky wrote: "The path of definitionand classification followed by psychology over the course of several centuriesled to the fact that of all the chapters of this science, the psychologyof feeling appeared to be fruitless and tedious."The merit of E. A. Salzen, the author of "Thwarted Action State Signalling Theory," is that much more important. He has tried to suggesta synthetic theory of emotions that integrates their psychologic, neurologic,and evolutionary-biological aspects. While reading Salzen's paper,I became convinced of the similarity of a number of its theses with myapproach to the nature of emotions, elaborated by me since 1964 (Simonov,1991)
Barriers and overcoming strategies to supply chain sustainability innovation
No full textThis study identifies a list of barriers that hinders adoption, implementation and upscaling of sustainable supply chain innovation in the manufacturing industry. It further proposes overcoming strategies that seek to aid management decision to dealing with these barriers systematically. A multi-criteria decision analysis method, the Best-Worst Method (BWM), is adopted to aid in the evaluation and prioritisation of the barriers and their overcoming strategies within the Indian manufacturing industry, an emerging economy. The results depict that, “lack of technical expertise and training”, “lack of R&D and innovation capabilities”, “popularity of traditional technology”, “high initial investment in latest technology” and “fear of extra workload and loss of flexibility” are the top five barriers that confronts the Indian manufacturing companies in their quest for adopting and implementing sustainable supply chain innovation practices. In addition, the overcoming strategic pathway for dealing with these barriers are provided. The findings provide managerial and policy insights for guiding the formation of strategic operations framework and resource allocation if these Indian manufacturing firms seeks to build sustainability into their supply chain innovations
Leveraged Buyouts and Private Equity
No full textWe describe and present time series evidence on the leveraged buyout/private equity industry, both firms and transactions. We discuss the existing empirical evidence on the economics of the firms and transactions. We consider similarities and differences between the recent private equity wave and the wave of the 1980s. Finally, we speculate on what the evidence implies for the future of private equity.PrivateEquity
The New Hungarian Pension System and its Problems
No full textIn January 1, 1998 a new, three-pillar pension system was introduced in Hungary. It will replace about a 1/4 of the existing unfunded public system by a funded private system from 2013. This transition is obligatory for people entering the labor market after June 30, 1998 and optional for others. Meanwhile the public pillar is also reformed. Pensionable age is increasing significantly but smoothly, wage index-ation is replaced by a combined wage-price indexation and the link between earnings and benefits will be rectified between 2009–2013. The official view is that it is this reform package which will make the Hungarian pension system sustainable in the long run and will contribute to the development of capital markets. The critics of the reforms, including the author, underline several remaining and new problems: the public pillar retains its weak points until 2013, the consolidated balance may deteriorate rather than improve under the partial privatization and the welfare of the old population will be relatively lower due to the decreased security.pension reforms, funding, economics in transition
Matting using a known background and a chroma-key minimization scheme
No full textIn this paper, we investigate the problem of segmenting the foreground objects from the known background. The target application is a setting where a large display serves as the backdrop for a scene. The method proposed in this paper solves this problem in two steps. We try to separate the foreground and the background with the modified background subtraction base technique, which involves taking the per-pixel difference of the image with and without the foreground. The modification includes blurring the image before taking the difference and finding contours to separate noise and small objects in the background from the foreground. If the background subtraction fails, the chroma-key method is used: we put the solid colour screen behind the foreground object to ease the separation. To minimize the adverse effects of the chroma-key on the lighting of the objects, we propose the method for the background screen minimization using the pinhole camera theory.CSE3000 Research ProjectComputer Science and Engineerin
К вопросу разработки методов реконструкции изображений в рентгеновской компьютерной томографии с конусным пучком излучения
No full textСимонов Евгений Николаевич, д-р техн. наук, профессор, заместитель директора по науке,
Южно-Уральский государственный университет, филиал в г. Кыштыме, г. Кыштым; e.n.simonov@
yandex.ru.
Аврамов Максим Витальевич, аспирант кафедры экономики, управления и информационных технологий, Южно-Уральский государственный университет, филиал в г. Кыштыме, г. Кыштым; [email protected]. E.N. Simonov, [email protected],
M.V. Avramov, [email protected]
South Ural State University, Kyshtym, Russian FederationThe article reflects the main task of the X-ray computed tomography and its mathematical
description. Direct and inverse Radon transform are given. The methods of image reconstruction in
X-ray computed tomography are presented. Their brief classification are given. The author have reviewed
classical problem of two-dimensional computed tomography and basics approaches to its solution.
Emphasis is placed on back projection algorithm with filtering convolution. The derivation of
the algorithm for parallel and fan-beam reconstruction are given. The analysis of the problem of
three-dimensional reconstruction are presented. The author describes the additional conditions imposed
on the projection data, the computational efficiency of the algorithms and the quality of
the images. The basic trajectory of the X-ray source, providing the condition Tuy, are considered.
The article gives an overview of existing methods of three-dimensional reconstruction with conebeam
geometry, their advantages, disadvantages, clinical applications. Their brief classification are
given. Approximate algorithms of three-dimensional reconstruction are presented. The Feldkamp algorithm,
the extended parallel backprojection, and the advanced single-slice rebinning are described.
The author raises the question of developing approaches and methods for obtaining images with
three-dimensional reconstruction for cone-beam spiral CT. Отражена основная задача рентгеновской компьютерной томографии и ее математическое описание. Приведено прямое и обратное преобразование Радона. В статье представлены
методы реконструкции изображений в рентгеновской компьютерной томографии. Дана их
краткая классификация. Автором рассмотрена классическая задача двумерной компьютерной
томографии, основные подходы к ее решению. Основное внимание уделено алгоритму обратного проецирования с фильтрацией сверткой. Приведен вывод алгоритма для параллельной и
веерной схем сканирования. Проанализирована задача трехмерной реконструкции изображений. Описаны дополнительные условия, накладываемые на полноту проекционных данных,
вычислительную эффективность алгоритмов, качество получаемых изображений. Рассмотрены основные траектории движения источника рентгеновского излучения, обеспечивающие
выполнение условия Кириллова – Смита – Туя. Основное внимание уделено спиральной траектории. Приведен анализ существующих методов трехмерной реконструкции с конусной геометрией лучей, их достоинства, недостатки, области применения. Дана их краткая классификация. Приведены алгоритмы, дающие приближенное решение задачи трехмерной реконструкции. Описаны алгоритм Фельдкампа, алгоритм обобщенной обратной проекции, модернизированный алгоритм однослойной перепаковки. Затронут вопрос разработки подходов и методов получения изображений при трехмерной реконструкции в конусе лучей для спиральной
компьютерной томографии
Backdoor attacks in federated learning with regression
No full textMachine learning, a pivotal aspect of artificial intelligence, has dramatically altered our interaction with technology and our handling of extensive data. Through its ability to learn and make decisions from patterns and previous experiences, machine learning is growing in influence on different aspects of our lives. It is, however, shown that machine learning can be attacked, and by the attacks, its functioning may become completely opposite of what it was designed. A special kind of attack on machine learning models is a backdoor attack. It uses a special pattern that was placed in the training data by malicious users to alter the models’ behaviour. This pattern is called a backdoor trigger, and it can take any possible form. The test data with this trigger will be misclassified, while the clean data will get a correct prediction. This property makes the backdoor attacks stealthy and hard to detect. The backdoor attacks are mostly created to attack the classification models, where for each data sample, there is a label. In this thesis, we move away from the classification setup and create the first (to our knowledge) backdoor attack on the linear regression. We show that the triggers constructed using different versions of feature selection algorithms can be effective and impose a high error on the linear learning model prediction. Additionally, the study shows that backdoor attacks with the trigger constructed with a feature selection using correlation analysis lead to a higher error than the one using random forest for feature selection. Furthermore, we also transfer this backdoor attack to the federated learning setup. The results prove to be highly dependent on the number of poisoned nodes, while for all of them, the error for the poisoned region is higher than for the clean data. Finally, for the attack in both setups, we have adapted popular defence mechanisms that work against backdoor attacks on classification models. For the centralised setup, we have explored the possibility of using the studentized residuals as an outlier detection mechanism. The results are diverse, becoming worse when the poisoning rate of the model increases. To prevent the attacks in the federated setup, we used the FoolsGold defence mechanism, and it proved to be effective against the backdoor attacks on the regression model in all the cases except the one with exactly one attacking node.Computer Science | Cyber Securit
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