bluuebunny/crossref_metadata_2025 huggingface dataset:
Computable Bounds on the Spectral Gap for Unreliable Jackson Networks
Authors: Lorek Paweł , Szekli Ryszard
Published: June 2015

The goal of this paper is to identify exponential convergence rates and to find computable bounds for them for Markov processes representing unreliable Jackson networks. First, we use the bounds of Lawler and Sokal (1988) in order to show that, for unreliable Jackson networks, the spectral gap is strictly positive if and only if the spectral gaps for the corresponding coordinate birth and death processes are positive. Next, utilizing some results on birth and death processes, we find bounds on the spectral gap for network processes in terms of the hazard and equilibrium functions of the one-dimensional marginal distributions of the stationary distribution of the network. These distributions must be in this case strongly light-tailed, in the sense that their discrete hazard functions have to be separated from 0. We relate these hazard functions with the corresponding networks' service rate functions using the equilibrium rates of the stationary one-dimensional marginal distributions. We compare the obtained bounds on the spectral gap with some other known bounds.
Staffing Many-Server Systems with Admission Control and Retrials
Authors: Janssen A. J. E. M. , van Leeuwaarden J. S. H.
Published: June 2015

In many-server systems it is crucial to staff the right number of servers so that targeted service levels are met. These staffing problems typically lead to constraint satisfaction problems that are difficult to solve. During the last decade, a powerful many-server asymptotic theory has been developed to solve such problems and optimal staffing rules are known to obey the square-root staffing principle. In this paper we develop many-server asymptotics in the so-called quality and efficiency driven regime, and present refinements to many-server asymptotics and square-root staffing for a Markovian queueing model with admission control and retrials.
Admission Control for Multidimensional Workload input with Heavy Tails and Fractional Ornstein-Uhlenbeck Process
Authors: Budhiraja Amarjit , Pipiras Vladas , Song Xiaoming
Published: June 2015

The infinite source Poisson arrival model with heavy-tailed workload distributions has attracted much attention, especially in the modeling of data packet traffic in communication networks. In particular, it is well known that under suitable assumptions on the source arrival rate, the centered and scaled cumulative workload input process for the underlying processing system can be approximated by fractional Brownian motion. In many applications one is interested in the stabilization of the work inflow to the system by modifying the net input rate, using an appropriate admission control policy. In this paper we study a natural family of admission control policies which keep the associated scaled cumulative workload input asymptotically close to a prespecified linear trajectory, uniformly over time. Under such admission control policies and with natural assumptions on arrival distributions, suitably scaled and centered cumulative workload input processes are shown to converge weakly in the path space to the solution of a d-dimensional stochastic differential equation driven by a Gaussian process. It is shown that the admission control policy achieves moment stabilization in that the second moment of the solution to the stochastic differential equation (averaged over the d-stations) is bounded uniformly for all times. In one special case of control policies, as time approaches ∞, we obtain a fractional version of a stationary Ornstein-Uhlenbeck process that is driven by fractional Brownian motion with Hurst parameter H > ½.
Burn-in Procedure Based on a Dependent Covariate Process
Authors: Cha Ji Hwan , Pulcini Gianpaolo
Published: June 2015

Burn-in is a method of ‘elimination’ of initial failures (infant mortality). In the conventional burn-in procedures, to burn-in a component or a system means to subject it to a fixed time period of simulated use prior to actual operation. Then those which fail during the burn-in procedure are scrapped and only those which survived the burn-in procedure are considered to be of satisfactory quality. Thus, in this case, the only information used for the elimination procedure is the lifetime of the corresponding item. In this paper we consider a new burn-in procedure which additionally employs a dependent covariate process in the elimination procedure. Through the comparison with the conventional burn-in procedure, we show that the new burn-in procedure is preferable under commonly satisfied conditions. The problem of determining the optimal burn-in parameters is also considered and the properties of the optimal parameters are derived. A numerical example is provided to illustrate the theoretical results obtained in this paper.
Skeletons of Near-Critical Bienaymé-Galton-Watson Branching Processes
Authors: Sagitov Serik , Serra Maria Conceição
Published: June 2015

Skeletons of branching processes are defined as trees of lineages characterized by an appropriate signature of future reproduction success. In the supercritical case a natural choice is to look for the lineages that survive forever (O'Connell (1993)). In the critical case it was suggested that the particles with the total number of descendants exceeding a certain threshold could be distinguished (see Sagitov (1997)). These two definitions lead to asymptotic representations of the skeletons as either pure birth process (in the slightly supercritical case) or critical birth-death processes (in the critical case conditioned on the total number of particles exceeding a high threshold value). The limit skeletons reveal typical survival scenarios for the underlying branching processes. In this paper we consider near-critical Bienaymé-Galton-Watson processes and define their skeletons using marking of particles. If marking is rare, such skeletons are approximated by birth and death processes, which can be subcritical, critical, or supercritical. We obtain the limit skeleton for a sequential mutation model (Sagitov and Serra (2009)) and compute the density distribution function for the time to escape from extinction.
Exponential Growth of Bifurcating Processes with Ancestral Dependence
Authors: Louhichi Sana , Ycart Bernard
Published: June 2015

Branching processes are classical growth models in cell kinetics. In their construction, it is usually assumed that cell lifetimes are independent random variables, which has been proved false in experiments. Models of dependent lifetimes are considered here, in particular bifurcating Markov chains. Under the hypotheses of stationarity and multiplicative ergodicity, the corresponding branching process is proved to have the same type of asymptotics as its classic counterpart in the independent and identically distributed supercritical case: the cell population grows exponentially, the growth rate being related to the exponent of multiplicative ergodicity, in a similar way as to the Laplace transform of lifetimes in the i.i.d. case. An identifiable model for which the multiplicative ergodicity coefficients and the growth rate can be explicitly computed is proposed.
Phase Transitions for Random Geometric Preferential Attachment Graphs
Authors: Jordan Jonathan , Wade Andrew R.
Published: June 2015

Vertices arrive sequentially in space and are joined to existing vertices at random according to a preferential rule combining degree and spatial proximity. We investigate phase transitions in the resulting graph as the relative strengths of these two components of the attachment rule are varied.

Previous work of one of the authors showed that when the geometric component is weak, the limiting degree sequence mimics the standard Barabási-Albert preferential attachment model. We show that at the other extreme, in the case of a sufficiently strong geometric component, the limiting degree sequence mimics a purely geometric model, the on-line nearest-neighbour graph, for which we prove some extensions of known results. We also show the presence of an intermediate regime, with behaviour distinct from both the on-line nearest-neighbour graph and the Barabási-Albert model; in this regime, we obtain a stretched exponential upper bound on the degree sequence.
First Passage Percolation on Inhomogeneous Random Graphs
Authors: Kolossváry István , Komjáthy Júlia
Published: June 2015

In this paper we investigate first passage percolation on an inhomogeneous random graph model introduced by Bollobás et al. (2007). Each vertex in the graph has a type from a type space, and edge probabilities are independent, but depend on the types of the end vertices. Each edge is given an independent exponential weight. We determine the distribution of the weight of the shortest path between uniformly chosen vertices in the giant component and show that the hopcount, i.e. the number of edges on this minimal-weight path, properly normalized, follows a central limit theorem. We handle the cases where the average number of neighbors λ̃n of a vertex tends to a finite λ̃ in full generality and consider λ̃ = ∞ under mild assumptions. This paper is a generalization of the paper of Bhamidi et al. (2011), where first passage percolation is explored on the Erdős-Rényi graphs.
What is “Small Talk” About
Authors: Агеева  , Ageeva Yu.
Published: June 2015

The article illustrates uniqueness of verbal behavior of a recruiter and an

interviewee during the job interview through implementation of verbal tactics

of “small talk”. Linguistic features of four main types of this tactics are defined

and described (conversation about vacation and free time; conversation

about hobbies; conversation about family; conversation about the past).

It is found that while having small talk the job seeker may demonstrate personal

attributes as well as professional qualities, motivation and life principles.

The usage of the tactics allows HR manager avoiding socially desirable

answers and making the right choice within the limited period of time.
Сommunicative Model of Multilingual Education
Authors: Дубинский  , Dubinskiy Vladimir
Published: June 2015

The article presents a model of teaching four foreign languages. The

languages obligatory for learning are English and German. The student

then chooses the languages of distant cultures, for example, Chinese

and Czech, Japanese and Polish, Turkish and Serbian, etc. The teaching

materials are course books from Germany while methods of teaching foreign

languages are Russian and take into account personal characteristics and

abilities of the students. Original German material is borrowed from other

sources including the Internet. In the first two years, classes are given by

two highly skilled teachers who aim to show the common features of English

and German as the languages belonging to the same Germanic group. In

the next two years students analyze the differences of distant cultures,

with reference to the languages they choose for learning, as language

constitutes part of culture. The suggested model has a universal character

and can be used in any type of educational institutions. After finishing the

course, graduates have skills to teach the respective languages as well as

to translate and interpret from and into them.
Problems of Adaptation of Chinese Students in the Preparatory Department of the Russian Technical University
Authors: Баранникова  , Barannikova G.
Published: June 2015

The article considers the problems of adaptation of Chinese students in the

preparatory faculty of the Russian technical universities. There are marked

differences in the systems of teaching in China and in Russia. The article

describes traditional features of Chinese national character and their changes

in recent years. It analyzes changes in Chinese students. The necessity

of taking into account individual characteristics of Chinese students and

creating a favorable psychological-pedagogical conditions of cooperation in

the classroom are described.
Politeness as a Speech Mechanism of Successful Business Communication for Nowaday Professional
Authors: Ершова  , Ershova S. , Сиражова  , Sirazhova Z.
Published: June 2015

The article regards the issue of developing the politeness as an essential condition of modern professional communication specialist. The article reviews national forms of professional courtesy adopted in Russian and Uzbek, as well as their role in the process of business communication.
The Problems of Formation of Communicative Competence of Secondary School Students in the Spanish Classes
Authors: Сударь  , Sudar G.
Published: June 2015

In this article the problem of providing Spanish language classes with new

updated materials meeting the requirements of communicative approach

in foreign language teaching in high school is being raised. The emphasis

is placed on training students to master the written language
Holding certain types of legal expertise in criminal cases related to illegal forestry
Authors: Булгакова Марина , Bulgakova Marina
Published: June 2015

The article highlights the problem of illegal logging of forest plantations in Russia, the scientific and procedural component of the systematic work of the various organizations and agencies to develop mechanisms for combating crime in the forest industry, representing the author´s vision of a separate investigation of the type of environmental crime under the economic security of the state.

The author notes that a variety of disorders related to forest management are not new types of offenses in the country. Even in the XIX century, the Russian Empire basic directions of state activity to prevent violations of forest law were enshrined in the Charter of the Forest, which listed offenses and crimes and defined punishment for their commission. The annual growth in the number of offenses detected by law enforcement agencies in terms of violations of forest law, entails the need to create the most effective ways to detect, capture and examinate evidence. In this examination of the scene, primary investigative actions must be paid special attention. It is, in our opinion, should be done at a high level, carefully and accurately, which would continue to form the evidence base to carry out a sufficient number of different examinations, including forensic botanical using dendrochronology methods. The conclusion of the forensic botanical examination may serve as confirmation of the legality of timber, as well as a means of quality control of products of wood.
Study of the legal basis of housing mortgage
Authors: Бугрова Валентина , Bugrova Valentina , Малыгина Анна , Malygina Anna
Published: June 2015

In the Bulgakov´s novel, "Master and Margarita", it is said that people are spoilt by the housing problem. But, probably, and in today´s society it is more than ever, and for most Russians the housing problem remains a major issue.

Contrary to popular belief about the novelty of the mortgage, it has been around for a long time, since the time of the Archon Solon, who lived in the VI BC.

But in Russia, the first mention of the so-called "mortgage" is dated XIII century. In XVIII-XIX centuries under Catherine II and Alexander II mortgage loans were most actively developed. However, at the beginning of the XX century, after the October Revolution of 1917, the concept of "mortgage" gradually disappeared from everyday life and considered as a "bourgeois phenomenon". The origin of the "new" Russian mortgage started in the early 90s of the twentieth century, but only by 2000, there have been real positive conditions and trends of its development.

Mortgage as a form of solution of housing problem is widely discussed by legislators, society and the media. It is difficult to find legal or economic magazine or newspaper, which had not raised the issue of mortgage and related numerous problems. It happens that the opinions of authors on various issues differ, but one thing they are in agreement – it is necessary to develop the mortgage.

The article deals with current issues of lending to households and features of home mortgages.
National state ideology
Authors: Мишуров Иван , Mishurov Ivan , Мишурова Ольга , Mishurova Olga
Published: June 2015

The article is devoted to justifying the need for the existence of state ideology, its national foundations and adjustments to article 13 of the Russian Constitution to delete provisions of the absence of the state ideology of the Russian Federation.

State ideology is present in each state. The importance of this phenomenon has led to much attention to it by philosophers, politicians and other scientists over the past two centuries. There are different views on the concept of "ideology" and different ideological schools: liberalism, conservatism, anarchism, social democracy, socialism, and others. This diversity is defined by different needs and interests of social groups, media and spokesmen of ideological views.

Ideology is an articulation of the fundamental interests of large social groups (forces) of the society, it is a system of views and ideas, which gives a complete interpretation of social and political life, its meaning, direction and prospects of showing certain ways of solving social problems. Ideologies are expressed in attitudes of communities to social problems and conflicts, objectives and generalized program of activities. The leading link here is represented by interests.

It is the state who expresses and defends the national interests, regulates, as a rule, with the help of legal norms the totality of socio-political, economic, national and family relations, thus contributing to the stabilization and development of society. It has the right to have its own (state, national or multi-national state) ideology. That is why the Russian government cannot but have a nation-state ideology. That is the need for national-state ideology that is proved in this article.
Genetyczne parantele partykuł i spójników
Authors: Kleszczowa Krystyna , Termińska Kamilla
Published: June 2015

Genetic kinship of particles and conjunctions

The paper attempts to explain the formal identity between those units which operate both in the class of conjunctions, and in the class of particles. To this purpose, the authors set in motion a logical apparatus that interpretes the identity between conclusive units; they choose, out of many possibilities, the resultative and the conclusive relation. The authors believe that the kinship of the two classes, particles and conjunctions, is the effect of operation of two mechanisms: 1. particles limit the scope of connectivity to introducing a sentence-shaped rheme, and become conjunctions proper (albowiem ‘because’, oraz ‘and’, bo ‘cause’, ale ‘but’); 2. particles connect to conjunctions, and take over their function (bowiem, albowiem ‘because’).
Idiosynkratyzm akomodacji morfologicznych wewnątrz i na zewnątrz fraz z liczebnikami typu pięć jako konsekwencja nieuzgodnienia cech przez mechanizm akomodacji składniowej
Authors: Willim Ewa
Published: June 2015

Idiosyncrasies in morphological agreement inside and outside phrases with numerals of the pięć ‘five’-type as a consequences of syntactic agreement failures

The paper discusses some problems inherent in the hypothesis on which numerals are heads that have a valued feature of case in nominative and accusative contexts. In the analysis offered here numerals and quantifiers are phrasal adjuncts in the extended projection of the noun whose head is a null functional category. 3 person, singular number and neuter gender verb morphology as well as alternating patterns of the morphology of pre-numeral and predicative adjectives reflect attempted but (partly) failed syntactic agreement.
Consumer views on A&E and inpatient care
Authors: Tingle John
Published: June 2015

John Tingle discusses the Care Quality Commission national survey results for hospital inpatient care along with results from the Patients Association and Royal College of Emergency Medicine patient survey report on A&E care
Evaluating an alternating mattress on an elderly rehabilitation ward
Authors: Gleeson Deborah
Published: June 2015

Pressure ulcer prevention is a primary requirement for the NHS. Robust nursing procedures and the provision of pressure-relieving equipment is vital in meeting this requirement. However, the Department of Health also regards making considerable financial savings as a fundamental requirement. There is a firm clinical consensus among national and international bodies that patients at a high risk of developing pressure ulcers, or with existing tissue damage, should be cared for on an alternating (pressure-relieving) mattress system. This evaluation process looks at the performance of the lower cost Air-Flo® 8 Acute alternating (pressure-relieving) mattress system to see if it is effective in meeting the needs of patients. The outcomes suggest that when combined with a pressure ulcer management plan and turning schedule the Air-Flo® 8 Acute performed well, giving an option to continue to care for high-risk patients with an empirically proven effective therapy, while making considerable financial savings.
General anaesthesia and the role of the dental nurse
Authors: Rooney Yvonne M , Boyle Carole A
Published: June 2015

In this article, Yvonne Rooney and Carole Boyle provide an overview of general anaesthesia (GA), the indications for treatment under GA, and the dental nurse's role when a patient comes in for treatment
Endodontic treatment part 1: the big issue over a little tissue
Authors: Emery Chris
Published: June 2015

In this three-part series, Chris Emery discusses a case study of a patient who has a pulpitis and the importance of the dental nurse's role in this treatment. In this article, an overview of the diagnosis is given
Patient awareness of dental recall intervals
Authors: Michelle LT Lo , Mary SF Lo
Published: June 2015

This article examines patients' understanding around the issue of dental recall intervals and the barriers that deter people from visiting the dentist. It also explains how dental nurses can help to educate their patients and how they can help people overcome their fear of visiting the dentist
Bridging the hierarchical and collaborative divide: the role of network managers in scaling up a network approach to water governance in California
Authors: Conrad Esther
Published: June 2015

Network governance represents an important approach to managing complex environmental challenges because of its capacity to support learning. However, multi-scalar problems often require networks to interface with hierarchical modes of governance. This paper examines how network managers can help mediate the potentially constraining influence of external demands on a network’s capacity for learning. It finds that a trusted lead agency can help bridge the hierarchical and collaborative divide by brokering across regional and state-level interests, developing processes that transform external requirements into learning opportunities, and supporting the development of informal dynamics in addition to formal rule compliance.
Scaling up networks for starving artists
Authors: Farr-Wharton Ben , Keast Robyn
Published: June 2015

Creative industries development strategies have largely adopted a regionally embedded cluster platform to enhance the economic contribution of the sector. Such an isolated approach has done little to curb significant labour precarity and exploitation within the sector. Correspondingly, creative workers have sought to up-scale their networks, from local to global, to enhance their labour outcomes. This paper analyses the impact creative workers’ up-scaled network arrangements on their labour outcomes. The research identifies significant policy implications concerning the support of up-scaled arrangements for economic segments that are vulnerable to labour precarity, such as the creative industries.
The Study of Glioma by Xenotransplantation in Zebrafish Early Life Stages
Authors: Vittori Miloš , Motaln Helena , Turnšek Tamara Lah
Published: June 2015

Zebrafish ( Danio rerio) and their transparent embryos are becoming an increasingly popular tool for studying processes involved in tumor progression and in the search for novel tumor treatment approaches. The xenotransplantation of fluorescently labeled mammalian cancer cells into zebrafish embryos is an approach enabling relatively high-throughput in vivo analyses. The small size of the embryos as well as the relative simplicity of their manipulation and maintenance allow for large numbers of embryos to be processed efficiently in a short time and at low cost. Furthermore, the possibility of fluorescence microscopic imaging of tumor progression within zebrafish embryos and larvae holds unprecedented potential for the real-time visualization of these processes in vivo. This review presents the methodologies of xenotransplantation studies on zebrafish involving research on tumor invasion, proliferation, tumor-induced angiogenesis and screening for antitumor therapeutics. We further focus on the application of these zebrafish to the study of glioma; in particular, its most common and malignant form, glioblastoma.
The effects of CaCl2 and CaBr2 on the reproduction of Daphnia magna Straus / Učinak CaCl2 i CaBr2 na razmnožavanje vodenbuhe (Daphnia magna Straus)
Authors: Mažuran Neda , Hršak Vladimir , Kovačević Goran
Published: June 2015

Concentrated CaCl2 and CaBr2 salt solutions of densities up to 2.3 kg L-1 are regularly used to control hydrostatic pressure in oil wells during special operations in the exploration and production of natural gas and crude oil. Various concentrations of high density salts are frequently left in mud pits near the drilling site as waste, polluting fresh and ground waters by spillage and drainage. The toxic effects of these salts have already been observed. This study investigated the effects of CaCl2 and CaBr2 on water flea Daphnia magna Straus in a 21-day reproduction test. The three tested concentrations of CaCl2 (240, 481, and 1925 mg L-1) caused a significant dose-response decrease of reproduction (p<0.001). With CaBr2 (533 and 1066 mg L-1), only aborted eggs were produced, demonstrating the embryotoxicity of the substance. The results suggest that high concentrations of the tested chemicals are harmful to Daphnia’s reproduction and could reduce its abundance.
Nanoparticle interaction with the immune system / Interakcije nanodelcev z imunskim sistemom
Authors: Kononenko Veno , Narat Mojca , Drobne Damjana
Published: June 2015

When nanoparticles enter the body, their interactions with cells are almost unavoidable. Unintended nanoparticle interaction with immune cells may elicit a molecular response that can have toxic effects and lead to greater susceptibility to infectious diseases, autoimmune disorders, and cancer development. As evidenced by several studies, nanoparticle interactions with biological systems can stimulate inflammatory or allergic reactions and activate the complement system. Nanoparticles can also stimulate immune response by acting as adjuvants or as haptens. Immunosuppressive effects have also been reported. This article gives a brief review of in vitro and in vivo research evidencing stimulatory or suppressive effects of nanoparticles on the immune system of mammals. In order to ensure safe use of nanosized particles, future research should focus on how their physical and chemical properties influence their behaviour in the biological environment, as they not only greatly affect nanoparticle-immune system interactions but can also interfere with experimental assays
Growth and photosynthetic responses of Lemna minor L. exposed to cadmium in combination with zinc or copper / Rast i fotosinteza u vodene leće (Lemna minor L.) izložene kadmiju u kombinaciji s cinkom ili bakrom
Authors: Vidaković-Cifrek Željka , Tkalec Mirta , Šikić Sandra , Tolić Sonja , Lepeduš Hrvoje , Pevalek-Kozlina Branka
Published: June 2015

Metals have a variety of negative outcomes on plants, essential components of any ecosystem. The effects of CdCl2 (5 μmol L-1), ZnCl2 (25 or 50 μmol L-1), and CuCl2 (2.5 or 5 μmol L-1) and combinations of CdCl2 with either ZnCl2 or CuCl2 on the growth, photosynthetic pigments, and photosystem II (PSII) efficiency of duckweed (Lemna minor L.) were investigated. All of the treatments caused growth inhibition and remarkable metal accumulation in plant tissue after 4 and 7 days. In the combined treatments, the accumulation of each metal applied was lesser in comparison to treatments with single metals. After 4 days, all of the treatments generally diminished chlorophyll a content and decreased the maximum quantum yield (Fv/Fm) and effective quantum yield (ΔF/F’m) of PSII. However, after 7 days of exposure to a combination of Cd and Zn, pigment content and PSII activity recovered to control levels. A higher concentration of Cu (5 μmol L-1) as well as Cd in combination with Cu had a prolonged inhibitory effect on photosynthetic features. Our results suggest that growth inhibition was due to the toxic effect of absolute metal quantity in plant tissue. Zn counteracted Cd uptake, as seen from the recovery of pigment content and PSII efficiency in plants exposed for 7 days to the Cd and Zn combination. Cu-induced oxidative stress led to a prolonged inhibitory effect in plants treated both with a higher concentration of Cu (5 μmol L-1) and simultaneously with Cd and Cu. Our findings could contribute to general knowledge on anthropogenic and environmental contaminants that endanger plant communities and significantly disrupt the sensitive balance of an ecosystem by influencing photosynthetic mechanisms.
Comparative determination of the efficacy of bispyridinium oximes in paraoxon poisoning / Usporedno određivanje učinkovitosti bispiridinijevih oksima pri trovanju paraoksonom
Authors: Žunec Suzana , Radić Božica , Kuča Kamil , Musilek Kamil , Lucić Vrdoljak Ana
Published: June 2015

The inability of standard therapy to provide adequate protection against poisoning by organophosphorus compounds (pesticides and nerve agents) motivated us to search for new, more effective oximes. We investigated the pharmacotoxicological properties of six experimental K-oximes (K027, K033, K048, K074, K075, and K203) in vivo. The therapeutic efficacy of K-oximes (at doses of 5 or 25 % of their LD50) combined with atropine was assessed in paraoxon-poisoned mice and compared with conventionally used oximes HI-6 and TMB-4. The bisoxime K074 was the most toxic (LD50=21.4 mg kg-1) to mice, while monoxime K027 was the least toxic (LD50=672.8 mg kg-1). With the exception of K033, all of the tested K-oximes showed better therapeutic efficiency than HI-6 and TMB-4. K027 and K048 stood out by demonstrating low acute toxicities and ensuring protective indices ranging from 60.0 to 100.0 LD50 of paraoxon. Taking into account that these two oximes showed a similar therapeutic efficacy regardless of the applied doses, our results suggest that K027 and K048 could be antidotes for paraoxon intoxication.
Controllability of nonlinear stochastic systems with multiple time-varying delays in control
Authors: Karthikeyan Shanmugasundaram , Balachandran Krishnan , Sathya Murugesan
Published: June 2015

This paper is concerned with the problem of controllability of semi-linear stochastic systems with time varying multiple delays in control in finite dimensional spaces. Sufficient conditions are established for the relative controllability of semilinear stochastic systems by using the Banach fixed point theorem. A numerical example is given to illustrate the application of the theoretical results. Some important comments are also presented on existing results for the stochastic controllability of fractional dynamical systems.
Robust sensor fault estimation for descriptor-LPV systems with unmeasurable gain scheduling functions: Application to an anaerobic bioreactor
Authors: López-Estrada Francisco-Ronay , Ponsart Jean-Christophe , Astorga-Zaragoza Carlos-Manuel , Camas-Anzueto Jorge-Luis , Theilliol Didier
Published: June 2015

This paper addresses the design of a state estimation and sensor fault detection, isolation and fault estimation observer for descriptor-linear parameter varying (D-LPV) systems. In contrast to where the scheduling functions depend on some measurable time varying state, the proposed method considers the scheduling function depending on an unmeasurable state vector. In order to isolate, detect and estimate sensor faults, an augmented system is constructed by considering faults to be auxiliary state vectors. An unknown input LPV observer is designed to estimate simultaneously system states and faults. Sufficient conditions to guarantee stability and robustness against the uncertainty provided by the unmeasurable scheduling functions and the influence of disturbances are synthesized via a linear matrix inequality (LMI) formulation by considering H∞ and Lyapunov approaches. The performances of the proposed method are illustrated through the application to an anaerobic bioreactor model.
A hybrid procedure to identify the optimal stiffness coefficients of elastically restrained beams
Authors: Silva Tiago , Loja Maria , Maia Nuno , Barbosa Joaquim
Published: June 2015

The formulation of a bending vibration problem of an elastically restrained Bernoulli-Euler beam carrying a finite number of concentrated elements along its length is presented. In this study, the authors exploit the application of the differential evolution optimization technique to identify the torsional stiffness properties of the elastic supports of a Bernoulli-Euler beam. This hybrid strategy allows the determination of the natural frequencies and mode shapes of continuous beams, taking into account the effect of attached concentrated masses and rotational inertias, followed by a reconciliation step between the theoretical model results and the experimental ones. The proposed optimal identification of the elastic support parameters is computationally demanding if the exact eigenproblem solving is considered. Hence, the use of a Gaussian process regression as a meta-model is addressed. An experimental application is used in order to assess the accuracy of the estimated parameters throughout the comparison of the experimentally obtained natural frequency, from impact tests, and the correspondent computed eigenfrequency.
Genetic and combinatorial algorithms for optimal sizing and placement of active power filters
Authors: Maciążek Marcin , Grabowski Dariusz , Pasko Marian
Published: June 2015

The paper deals with cost effective compensator placement and sizing. It becomes one of the most important problems in contemporary electrical networks, in which voltage and current waveform distortions increase year-by-year reaching or even exceeding limit values. The suppression of distortions could be carried out by means of three types of compensators, i.e., passive filters, active power filters and hybrid filters. So far, passive filters have been more popular mainly because of economic reasons, but active and hybrid filters have some advantages which should cause their wider application in the near future. Active power filter placement and sizing could be regarded as an optimization problem. A few objective functions have been proposed for this problem. In this paper we compare solutions obtained by means of combinatorial and genetic approaches. The theoretical discussion is followed by examples of active power filter placement and sizing
The Role of Melatonin and Bromocriptine in the Regulation of Prolactin Secretion in Animals – A Review
Authors: Molik Edyta , Błasiak Michał
Published: June 2015

Changes in the concentration of melatonin and prolactin are associated with response to day length. The factors that stimulate the release of PRL include, among others, TRH, VIP, endorphins, oestrogen, and adrenaline. PRL secretion inhibitors include DA, GABA, progesterone and bromocriptine (exogenous compound), used in the treatment of hyperprolactinemia D2 receptor agonist. The biological activity of this compound is to stimulate dopamine D2 receptors in the pituitary, which inhibits PRL secretion via the tuberoinfundibular pathway (Fitzgerald and Dinan, 2008). In sheep treated with bromocriptine there is a decrease in PRL concentration and an increase in the sensitivity of cells producing LH to GnRH, but there is no disturbance in the course of the estrous cycle. Rams show decreased libido and changes in sexual behaviour. The administration of bromocriptine throughout the period of sexual activity and the period of rearing offspring affects maternal instinct, which involves the inhibition of PRL secretion. It is not clarified whether the effect of bromocriptine on sexual behaviour is associated with its direct impact on behavioural centres in the brain, or indirectly through the regulation of PRL secretion. However, the seasonal variations in the effects of bromocriptine on sexual behaviour can strengthen the hypothesis that the effect of bromocriptine on sexual development behaviour is associated with changes in the intensity of PRL secretion rather than by the inhibition of behavioural bromocriptine brain centres. The process of regulation of prolactin secretion by bromocriptine requires further examination.
Cooperation or Competition? A Field Experiment on Non-monetary Learning Incentives
Authors: Bigoni Maria , Fort Margherita , Nardotto Mattia , Reggiani Tommaso G.
Published: June 2015

We assess the effect of two antithetic non-monetary incentive schemes based on grading rules on students’ effort, using experimental data. We randomly assigned students to a tournament scheme that fosters competition between paired up students, a cooperative scheme that promotes information sharing and collaboration between students and a baseline treatment in which students can neither compete nor cooperate. In line with theoretical predictions, we find that competition induces higher effort with respect to cooperation, whereas cooperation does not increase effort with respect to the baseline treatment. Nonetheless, we find a strong gender effect since this result holds only for men while women do not react to this type of non-monetary incentives.
Design and construction of a polygon-connected autotransformer-based 36-pulse AC-DC converter for power quality improvement in retrofit applications
Authors: Abdollahi R.
Published: June 2015

This paper presents the design and analysis of a polygon connected autotransformer based 36-phase AC-DC converter which supplies direct torque controlled induction motor drives (DTCIMD’s) in order to have better power quality conditions at the point of common coupling. The proposed converter output voltage is accomplished via two paralleled eighteen-pulse AC-DC converters each of them consisting of nine-phase diode bridge rectifier. An autotransformer is designed to supply the rectifier. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. The proposed structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 4% for the proposed topology at variable loads. A laboratory prototype of the proposed Polygon-Connected autotransformer-based 36-pulse AC-DC converter is developed and test results are presented to validate the developed design procedure and the simulation models of this AC-DC converter under varying loads
Comparison of numerical and experimental study of armour system based on alumina and silicon carbide ceramics
Authors: Chabera P. , Boczkowska A. , Morka A. , Kędzierski P. , Niezgoda T. , Oziębło A. , Witek A.
Published: June 2015

The main goal of this numerical and experimental study of composite armour systems was to investigate their ballistic behaviour. Numerical simulations were employed to determine the initial dimensions of panel layers before the actual ballistic test. In order to achieve this aim, multivariate computations with different thicknesses of panel layers were conducted. Numerical calculations were performed with the finite element method in the LS-DYNA software, which is a commonly used tool for solving problems associated with shock wave propagation, blasts and impacts. An axisymmetric model was built in order to ensure sufficient discretization. Results of a simulation study allowed thicknesses of layers ensuring assumed level of protection to be determined.

According to the simulation results two armour configurations with different ceramics have been fabricated. The composite armour systems consisted of the front layer made of Al2O3 or SiC ceramic and high strength steel as the backing material. The ballistic performance of the proposed protective structures were tested with the use of 7.62 mm Armour Piercing (AP) projectile. A comparison of impact resistance of two defence systems with different ceramic has been carried out. Application of silicon carbide ceramic improved ballistic performance, as evidenced by smaller deformations of the second layer. In addition, one of armour systems was complemented with an intermediate ceramic-elastomer layer. A ceramic-elastomer component was obtained using pressure infiltration of gradient porous ceramic by elastomer. Upon ballistic impact, the ceramic body dissipated kinetic energy of the projectile. The residual energy was absorbed by the intermediate composite layer. It was found, that application of composite plates as a support of a ceramic body provided a decrease of the bullet penetration depth
Quantum simulation of the tunnel effect
Authors: Ostrowski M.
Published: June 2015

In this paper, we examine whether a quantum computer can efficiently simulate quantum processes such as the tunnel effect. We examine a quantum algorithm that calculates the value of transition and reflection coefficients for the Gaussian wave packet scattered on a rectangular potential. We compare the results obtained in this way with the results of classical simulations and analytical calculations
Finite element analysis for airfield asphalt pavements rutting prediction
Authors: Leonardi G.
Published: June 2015

This paper presents a numerical study of an aircraft wheel impacting on a flexible pavement. The proposed three dimensional model simulates the behaviour of flexible runway pavement during the landing phase. This model was implemented in a finite element code in order to investigate the impact of repeated cycles of loads on pavement permanent deformation.

In the model a traditional multi-layer pavement structure was considered. In addition, the asphalt layer (HMA) was assumed to follow an elasto-viscoplastic behaviour.

The results demonstrate the capability of the model in predicting the permanent deformation distribution in the asphalt layer
On simplified forms of the fractional-order backward difference and related fractional-order linear discrete-time system description
Authors: Ostalczyk P.
Published: June 2015

In this paper three simplified forms of the fractional-order (FO) backward difference (BD) are proposed and analysed. Due to time and frequency characteristics criteria parameters of simplified forms of the FOBDs are chosen. Applications of the simplified forms of the FOBDs diminish a number of multiplications and additions needed to evaluate the FOBD. This is very important in real-time microprocessor calculations. It is proved that in a discrete state-space description of a fractional-order system one should correct the input matrix with simplified forms of the FOBD. Investigations are supported by two numerical examples
Assessment of Polish Power System angular stability based on analysis of different disturbance waveforms
Authors: Pruski P. , Paszek S.
Published: June 2015

The paper presents investigation results concerning assessment of the Polish Power System (PPS) angular stability based on power system state matrix eigenvalues associated with electromechanical phenomena, when using the angular stability factors calculated on the basis of these eigenvalues. The eigenvalues were calculated by analysis of the disturbance waveforms of the instantaneous power, angular speed and power angle of synchronous generators in PPS generating units when taking into account introduction of a disturbance to different units. There was assumed a disturbance in the form of a rectangular pulse introduced to the voltage regulation system of a generating unit. There was also analysed the effect of the duration of the introduced test disturbance on the calculation results of the eigenvalue influencing the measurement waveforms of the instantaneous power of generating unit no 5 in Rybnik Power Plant. The method for eigenvalue calculations used in the investigations consists in approximation of the disturbance waveforms in particular generating units with the use of the waveforms being a superposition of the modal components associated with the searched eigenvalues. The hybrid optimisation algorithm being a serial combination of the genetic and gradient algorithms was used for computations
Determining selected diesel engine combustion descriptors based on the analysis of the coefficient of variation of in-chamber pressure
Authors: Bąkowski A. , Radziszewski L.
Published: June 2015

This paper presents a method that uses the coefficient of variation (COV) of pressure in a diesel engine combustion chamber to determine the crank angle degree (CAD) for which the heat release rate (HRR) reaches the maximum value. The COV was proposed for determining the point corresponding to the angle of start of combustion (SoC). Regression models were fit with these descriptors for the engine powered by diesel, biodiesel or a combination of both, operating under full- or part- load conditions. The uncertainty parameter in these models was determined. Good agreement between the experimental results and the literature data shows the validity of the analysis
Finite-time stability and stabilization of singular state-delay systems using improved estimation of a lower bound on a Lyapunov-like functional
Authors: Stojanovic S.B. , Debeljkovic D.Lj. , Antic D.S.
Published: June 2015

In this paper, the problems of finite-time stability and stabilization for a class of singular time-delay systems are studied. Using the Lyapunov-like functional (LLF) with (exponential or power) weighting function and a new estimation method for the lower bound on LLF, some sufficient stability conditions are introduced. It is shown that the weighting function significantly reduces the conservatism of the stability criteria in comparison to estimation of the lower bound on LLF without this function. To solve the finite-time stabilization problem, a stabilizing linear state controller is designed by exploiting the cone complementarity linearization algorithm. Two numerical examples are given to illustrate the effectiveness of the proposed method
The new, parametrised IPTV Model for Determining the Quality in the IPTV Service
Authors: Uhl T. , Jürgensen H.S.
Published: June 2015

This paper describes a new measurement method for determining the quality of the IPTV (Television over IP) service. This method uses the latest IPTV Model and is one of a number of parameter-based measuring techniques (offline operation, i.e. without intrusive measurement). It delivers results that come very close to those of the corresponding Perceptual Evaluation of Video Quality (PEVQ) curves. The method is quickly and easily implemented - one of the great advantages of using this method to measure QoS