On the asymptotic stability of feedback control systems containing a single time- varying element

Asymptotic stability of feedback control systems containing single time varying elemen

Antithetic and Monte Carlo kernel estimators for partial rankings

In the modern age, rankings data is ubiquitous and it is useful for a variety of applications such as recommender systems, multi-object tracking and preference learning. However, most rankings data encountered in the real world is incomplete, which prevents the direct application of existing modelling tools for complete rankings. Our contribution is a novel way to extend kernel methods for complete rankings to partial rankings, via consistent Monte Carlo estimators for Gram matrices: matrices of kernel values between pairs of observations. We also present a novel variance reduction scheme based on an antithetic variate construction between permutations to obtain an improved estimator for the Mallows kernel. The corresponding antithetic kernel estimator has lower variance and we demonstrate empirically that it has a better performance in a variety of Machine Learning tasks. Both kernel estimators are based on extending kernel mean embeddings to the embedding of a set of full rankings consistent with an observed partial ranking. They form a computationally tractable alternative to previous approaches for partial rankings data. An overview of the existing kernels and metrics for permutations is also provided

Aromatic hydrocarbons as ozone precursors before and after outbreak of the 2008 financial crisis in the Pearl River Delta region, south China

In the second half of 2008 China's highly industrialized Pearl River Delta (PRD) region was hard-hit by the financial crisis (FC). This study reports volatile organic compounds measured in the PRD during November-December in both 2007 before the FC and 2008 after the FC. While total mixing ratios of non-methane hydrocarbons (NMHCs) on average were only about 7% lower from 40.2 ppbv in 2007 to 37.5 ppbv in 2008, their ozone formation potentials (OFPs) dropped about 30%, resulting from about 55% plummet of aromatic hydrocarbons (AHs) against a greater than 20% increase of total alkanes/alkenes. The elevated alkanes and alkenes in 2008 could be explained by greater emissions from vehicle exhausts and LPG combustion due to rapid increase of vehicle numbers and LPG consumption; the drop of AHs could be explained by reduced emissions from industries using AH-containing solvents due to the influence of the FC, as indicated by much lower ratios of toluene to benzene and of xylenes/ trichloroethylene/tetrachloroethylene to carbon monoxide (CO) in 2008. Source apportionment by positive matrix factorization (PMF) also revealed much less contribution of industry solvents to total anthropogenic NMHCs and particularly to toluene and xylenes in 2008 than in 2007. Based on PMF reconstructed source contributions, calculated OFPs by industrial emissions were responsible for 40.8% in 2007 in contrast to 18.4% in 2008. Further investigation into local industry output statistics suggested that the plummet of AHs in 2008 should be attributed to small enterprises, which contributed largely to ambient AHs due to their huge numbers and non-existent emission treatment, but were much more influenced by the FC. © 2012. American Geophysical Union. All Rights Reserved

Optimization of a company’s property structure aiming at maximization of its profit using neural networks with the example of a set of construction companies

This contribution tries to find an efficient way of a company´s property optimization. It searches for such a property structure that would ensure adequate benefit, respectively, the appreciation of own capital provided for remuneration. To carry out the calculation balance sheets, respectively their parts informing about the company´s property are used, as well as income statements – the total taxed profit of all companies running their business in the CZ from 2006 to 2015. To find the model artificial neural networks are used – specifically a multi-layer perceptron network and a neural network of a radial basic function. The result is a neural structure that will help the building company find a suitable property structure, so that the company reaches the required ROE of 10% (a company is considered successful, if it reaches 10% and more on Return on Equity). The model is useful not only in company management but also in evaluating its performance and health by competitors, creditors or suppliers.Стаття присвячена аналізу одного з варіантів можливої оптимізації власного капіталу компанії. Наведено підхід до пошуку оптимальної структури капіталу, який дозволить забезпечити адекватну вигоду і зробити оцінку власного капіталу. Підхід базується на традиційному аналізі балансів, деталізації майна компанії, звітах про прибутки та збитки – загальних звітах для всіх компаній Чеської Республіки з 2006 по 2015 р. Для побудови моделі на основі нейронної мережі використовуються багатошарові мережі персептрона і нейронні мережі з радіально-базисною функцією. У результаті отримана нейронна структура для оптимізації капіталу будівельної компанії з необхідною рентабельністю власного капіталу в 10% (компанія вважається успішною, якщо вона досягає 10% і більше рентабельності власного капіталу). Модель призначена не тільки для управління компаніями, але й для оцінки їх продуктивності та працездатності конкурентами, кредиторами або постачальниками.Данная работа посвящена анализу одного из вариантов возможной оптимизации собственного капитала компании. Представлен подход к поиску оптимальной структуры капитала, которая позволит обеспечить адекватную выгоду и произвести оценку собственного капитала. Подход базируется на традиционном анализе балансов, детализации имущества компании, отчетах о прибылях и убытках – общих отчетах для всех компаний Чешской Республики с 2006 по 2015 г. Для построения модели на основе нейронной сети используются многослойные сети персептрона и нейронные сети с радиально-базисной функцией. В результате получена нейронная структура для оптимизации капитала строительной компании с необходимой рентабельностью собственного капитала в 10% (компания считается успешной, если она достигает 10% и более по рентабельности собственного капитала). Модель предназначена не только для управления компаниями, но и для оценки их производительности и работоспособности конкурентами, кредиторами или поставщиками

Prediction of the future development of construction companies by means of artificial neural networks on the basis of data from the Czech Republic

The construction sector is one of the main pillars of an advanced economy. It is the first sector to indicate potential national economic problems. In a similar way it is the first sector to show signs of recovery when an economy is coming out of recession or crisis. The aim of this article is to apply a neural network to be able to predict potential financial problems in construction companies in the Czech Republic.Будівельна галузь є однією з найважливіших галузей у всіх розвинених економіках світу. Вона першою вказує на потенційні проблеми національної економіки і першою ж сигналізує про ознаки відновлення в економіці, яка виходить з рецесії або навіть кризи. Мета цієї статті полягає у використанні нейронних мереж для прогнозування потенційних фінансових труднощів будівельних компаній в Чеській Республіці.Строительная промышленность является одним из основных столпов всех развитых экономик мира. На ней в первую очередь отражаются возможные проблемы национальной экономики. На ней же одной из первых проявляется возможное улучшение состояния экономики, выходящей из состояния рецессии или даже кризиса. Целью статьи является использование нейронной сети для прогнозирования возможных финансовых затруднений строительных предприятий Чешской Республики

Estimates for local and movement-based transmission of bovine tuberculosis in British cattle

Both badgers and livestock movements have been implicated in contributing to the ongoing epidemic of bovine tuberculosis (BTB) in British cattle. However, the relative contributions of these and other causes are not well quantified. We used cattle movement data to construct an individual (premises)-based model of BTB spread within Great Britain, accounting for spread due to recorded cattle movements and other causes. Outbreak data for 2004 were best explained by a model attributing 16% of herd infections directly to cattle movements, and a further 9% unexplained, potentially including spread from unrecorded movements. The best-fit model assumed low levels of cattle-to-cattle transmission. The remaining 75% of infection was attributed to local effects within specific high-risk areas. Annual and biennial testing is mandatory for herds deemed at high risk of infection, as is pre-movement testing from such herds. The herds identified as high risk in 2004 by our model are in broad agreement with those officially designated as such at that time. However, border areas at the edges of high-risk regions are different, suggesting possible areas that should be targeted to prevent further geographical spread of disease. With these areas expanding rapidly over the last decade, their close surveillance is important to both identify infected herds quickly, and limit their further growth

Contact structures in the poultry industry in Great Britain: Exploring transmission routes for a potential avian influenza virus epidemic

Background: The commercial poultry industry in United Kingdom (UK) is worth an estimated £3.4 billion at retail value, producing over 174 million birds for consumption per year. An epidemic of any poultry disease with high mortality or which is zoonotic, such as avian influenza virus (AIV), would result in the culling of significant numbers of birds, as seen in the Netherlands in 2003 and Italy in 2000. Such an epidemic would cost the UK government millions of pounds in compensation costs, with further economic losses through reduction of international and UK consumption of British poultry. In order to better inform policy advisers and makers on the potential for a large epidemic in GB, we investigate the role that interactions amongst premises within the British commercial poultry industry could play in promoting an AIV epidemic, given an introduction of the virus in a specific part of poultry industry in Great Britain (GB). Results: Poultry premises using multiple slaughterhouses lead to a large number of premises being potentially connected, with the resultant potential for large and sometimes widespread epidemics. Catching companies can also potentially link a large proportion of the poultry population. Critical to this is the maximum distance traveled by catching companies between premises and whether or not between-species transmission could occur within individual premises. Premises closely linked by proximity may result in connections being formed between different species and or sectors within the industry. Conclusion: Even quite well-contained epidemics have the potential for geographically widespread dissemination, potentially resulting in severe logistical problems for epidemic control, and with economic impact on a large part of the country. Premises sending birds to multiple slaughterhouses or housing multiple species may act as a bridge between otherwise separate sectors of the industry, resulting in the potential for large epidemics. Investment into further data collection and analyses on the importance of industry structure as a determinant for spread of AIV would enable us to use the results from this study to contribute to policy on disease control

Evaluation of Solvency of potential customers of a company

The manufacturing sector is one of the main pillars of an advanced economy. It is the first sector to indicate potential national economic problems. In a similar way it is the first sector to show signs of recovery when an economy is coming out of recession or crisis. The aim of this article is to apply a neural network to be able to predict potential financial problems in manufacturing companies in the Czech Republic.Строительная отрасль является одной из ключевых отраслей всех развитых экономик мира. Раньше других отраслей она указывает на потенциальные проблемы национальной экономики. Раньше других отраслей она указывает и на потенциальное улучшение экономики, которая выходит из рецессии или даже из кризиса. Целью этой статьи является использование нейронных сетей для прогнозирования возможных финансовых трудностей строительных компаний в Чешской Республике.Будівельна галузь є однією з ключових галузей всіх розвинених економік світу. Раніше інших галузей вона вказує на потенційні проблеми національної економіки. Раніше інших галузей вона вказує і на потенційне поліпшення економіки, яка виходить з рецесії або навіть з кризи. Метою цієї статті є використання нейронних мереж для прогнозування можливих фінансових труднощів будівельних компаній в Чеській Республіці

Dynamic compartmentalization of bacteria: accurate division in E. coli

Positioning of the midcell division plane within the bacterium E. coli is controlled by the min system of proteins: MinC, MinD and MinE. These proteins coherently oscillate from end to end of the bacterium. We present a reaction--diffusion model describing the diffusion of min proteins along the bacterium and their transfer between the cytoplasmic membrane and cytoplasm. Our model spontaneously generates protein oscillations in good agreement with experiments. We explore the oscillation stability, frequency and wavelength as a function of protein concentration and bacterial length.Comment: 4 pages, 4 figures, Latex2e, Revtex

Asymmetry Dependence of the Nuclear Caloric Curve

A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron-proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A=50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry (N-Z)/A. An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei