Renewal Redundant Systems Under the Marshall–Olkin Failure Model. A Probability Analysis

In this paper a two component redundant renewable system operating under the Marshall–Olkin failure model is considered. The purpose of the study is to find analytical expressions for the time dependent and the steady state characteristics of the system. The system cycle process characteristics are analyzed by the use of probability interpretation of the Laplace–Stieltjes transformations (LSTs), and of probability generating functions (PGFs). In this way the long mathematical analytic derivations are avoid. As results of the investigations, the main reliability characteristics of the system—the reliability function and the steady state probabilities—have been found in analytical form. Our approach can be used in the studies of various applications of systems with dependent failures between their elements

On Reliability of a Double Redundant Renewable System with a Generally Distributed Life and Repair Times

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Indication of connectivity of the disperse material

In order to obtain quick information about the connectivity of the dust in the production test system-cleaning it is advisable to use the concept of connectivity indicator, which characterizes all kinds of strength characteristics of particulate material when changing conditions of particle interactions. Offers a simple method of indication of cohesion of particulate material, influencing the formation of sediment particles in the nozzle

DNA Codes Based on Stem Similarities Between DNA Sequences

DNA codes consisting of DNA sequences are necessary for DNA computing. The minimum distance parameter of such codes is a measure of how dissimilar the codewords are, and thus is indirectly a measure of the likelihood of undetectedable or uncorrectable errors occurring during hybridization. To compute distance, an abstract metric, for example, longest common subsequence, must be used to model the actual bonding energies of DNA strands. In this paper we continue the development [1,2,3] of similarity functions for q-ary n-sequences The theoretical lower bound on the maximal possible size of codes, built on the space endowed with this metric, is obtained. that can be used (for q = 4) to model a thermodynamic similarity on DNA sequences. We introduce the concept of a stem similarity function and discuss DNA codes [2] based on the stem similarity. We suggest an optimal construction [2] and obtain random coding bounds on the maximum size and rate for such codes

Superconductivity in silicon nanostructures

We present the findings of the superconductivity observed in the silicon nanostructures prepared by short time diffusion of boron on the n-type Si(100) surface. These Si-based nanostructures represent the p-type ultra-narrow self-assembled silicon quantum wells, 2nm, confined by the delta - barriers heavily doped with boron, 3nm. The EPR and the thermo-emf studies show that the delta - barriers appear to consist of the trigonal dipole centres, which are caused by the negative-U reconstruction of the shallow boron acceptors. Using the CV and thermo-emf techniques, the transport of two-dimensional holes inside SQW is demonstrated to be accompanied by single-hole tunneling through these negative-U centres that results in the superconductivity of the delta - barriers. The values of the correlation gaps obtained from these measurements are in a good agreement with the data derived from the temperature and magnetic field dependencies of the magnetic susceptibility, which reveal a strong diamagnetism and additionally identify the superconductor gap value.Comment: 4 pages, 6 figures, presented at the 4th International Conference on Vortex Matter in Superconductors, Crete, Greece, September 3-9, 200

Inertia-Based Indices to Determine the Number of Clusters in K-Means: An Experimental Evaluation

This paper gives an experimentally supported review and comparison of several indices based on the conventional K-means inertia criterion for determining the number of clusters, K , in datasets, using the popular Silhouette width index as a benchmark. Our experiments involve a novel version of the Elbow index, defined using values of K two or three steps apart. We also discuss alternative ways of computing the inertia and summarizing its values. Even though there are no overall winners in our experiments, some of our results are very conclusive and can be used as a guide for indices determining the number of clusters in K-means

Клинико-экономический анализ использования различных систем венозного доступа при лечении детей с онкологическими заболеваниями

Introduction. In the article the clinical and economic analysis of the use of different systems of venous access in the treatment of children with cancer.Objective: to conduct clinical and economic analysis systems venous access in order to optimize the cost of treatment of children with cancer.Materials and Methods. The experience of installing and operating the subclavian catheters and implantable venous port systems installed in 2262 for children between the ages of 2 months up to 17 years. To calculate the cost price were taken «Price list of paid medical services» and Rates of the compulsory health insurance.Results. As the number of annual primary identified children with cancer is on average 3.000 people, according to the price list prices temporarily, for the installation of each of them for a period of treatment five subclavian catheters necessary to spend 227.25 mln. rubles. And the implantations of venous ports – 156.00 mln. rubles. Thus, the savings of using implantable venous port-systems – 71.25 mln. rubles.Conclusion. Mass introduction of the implantable venous ports will significantly reduce the cost of budgetary funds for the treatment of children with cancer, while lowering the percentage of complications and improve quality of life.В статье проведен клинико-экономический анализ использования различных систем венозного доступа при лечении детей с онкологическими заболеваниями.Цель работы – провести клинико-экономический анализ систем венозного доступа с целью оптимизации расходов на лечение детей с онкологическими заболеваниями.Материалы и методы. Проанализирован опыт установки и эксплуатации подключичных катетеров и имплантируемых венозных порт-систем у 2262 детей в возрасте от 2 мес. до 17 лет. Для расчетов затрат были взяты цены «Временного прейскуранта платных медицинских услуг» РОНЦ им. Н.Н. Блохина и тарифы ОМС.Результаты. Поскольку количество ежегодно выявляемых первичных детей с онкологическими заболеваниями составляет в среднем 3000 человек, согласно ценам временного прейскуранта на установку каждому из них за период лечения пяти внешних центральных венозных катетеров необходимо затратить 227250000 руб., а на имплантацию порт-систем – 156000000 руб. Таким образом, экономия при использовании имплантируемых венозных порт-систем составляет 71250000 руб.Заключение. Массовое внедрение имплантируемых венозных порт-систем позволит существенно сократить расходы бюджетных средств на лечение детей с онкологическими заболеваниями, одновременно снизив процент осложнений и повысив качество жизни

Reliability-Centric Analysis of Offloaded Computation in Cooperative Wearable Applications

Motivated by the unprecedented penetration of mobile communications technology, this work carefully brings into perspective the challenges related to heterogeneous communications and offloaded computation operating in cases of fault-tolerant computation, computing, and caching. We specifically focus on the emerging augmented reality applications that require reliable delegation of the computing and caching functionality to proximate resource-rich devices. The corresponding mathematical model proposed in this work becomes of value to assess system-level reliability in cases where one or more nearby collaborating nodes become temporarily unavailable. Our produced analytical and simulation results corroborate the asymptotic insensitivity of the stationary reliability of the system in question (under the “fast” recovery of its elements) to the type of the “repair” time distribution, thus supporting the fault-tolerant system operation

Brown bear attacks on humans : a worldwide perspective

The increasing trend of large carnivore attacks on humans not only raises human safety concerns but may also undermine large carnivore conservation efforts. Although rare, attacks by brown bears Ursus arctos are also on the rise and, although several studies have addressed this issue at local scales, information is lacking on a worldwide scale. Here, we investigated brown bear attacks (n = 664) on humans between 2000 and 2015 across most of the range inhabited by the species: North America (n = 183), Europe (n = 291), and East (n = 190). When the attacks occurred, half of the people were engaged in leisure activities and the main scenario was an encounter with a female with cubs. Attacks have increased significantly over time and were more frequent at high bear and low human population densities. There was no significant difference in the number of attacks between continents or between countries with different hunting practices. Understanding global patterns of bear attacks can help reduce dangerous encounters and, consequently, is crucial for informing wildlife managers and the public about appropriate measures to reduce this kind of conflicts in bear country.Peer reviewe