The Distribution of Minimum of Ratios of Two Random Variables and Its Application in Analysis of Multi-hop Systems

The distributions of random variables are of interest in many areas of science. In this paper, ascertaining on the importance of multi-hop transmission in contemporary wireless communications systems operating over fading channels in the presence of cochannel interference, the probability density functions (PDFs) of minimum of arbitrary number of ratios of Rayleigh, Rician, Nakagami-m, Weibull and α-µ random variables are derived. These expressions can be used to study the outage probability as an important multi-hop system performance measure. Various numerical results complement the proposed mathematical analysis

Enhancing Fault / Intrusion Tolerance through Design and Configuration Diversity

Fault/intrusion tolerance is usually the only viable way of improving the system dependability and security in the presence of continuously evolving threats. Many of the solutions in the literature concern a specific snapshot in the production or deployment of a fault-tolerant system and no immediate considerations are made about how the system should evolve to deal with novel threats. In this paper we outline and evaluate a set of operating systems’ and applications’ reconfiguration rules which can be used to modify the state of a system replica prior to deployment or in between recoveries, and hence increase the replicas chance of a longer intrusion-free operation

Gamma process model for timber-concrete composite beam deterioration prediction

This paper presents the application of the advanced probabilistic slope stability model with precipitation effects (APSMP) developed to assess the performance of small homogeneous earthfill embankment dam slopes, when exposed to future seasonal precipitation scenarios. Here, the UKs latest probabilistic climate model known as UKCP09 is applied. To reflect the critical conditions conducive to slope failure, a benchmark has been developed to identify the change, if any, in the risk classification of the slope’s performance level due to precipitation. Thus, enabling the reassessment of the dam’s risk classification, as categorized by the Flood and Water Management Act 2010. Such an approach could therefore be well placed to support and enhance the decision making process, its impact on the public, especially in relation to future climate effects

FOREVER: Fault/intrusiOn REmoVal through Evolution & Recovery

The goal of the FOREVER project is to develop a service for Fault/intrusiOn REmoVal through Evolution & Recovery. In order to achieve this goal, our work addresses three main tasks: the definition of the FOREVER service architecture; the analysis of how diversity techniques can improve resilience; and the evaluation of the FOREVER service. The FOREVER service is an important contribution to intrustion-tolerant replication middleware and significantly enhances the resilience

Reproductive and Related Disorders on Dairy Farms with Different Levels of Welfare Quality

In this paper reproductive results of six dairy cows farms with total of 766 (farm 1 – 107; farm 2 –175; farm 3 – 49; farm 4 – 400; farm 5 –20 and farm 6 – 11 milking cows) with different system of rearing and welfare level were analyzed. A dairy cow reproductive efficiency is a key factor for milk production - impaired reproductive performance is a major cause of reduced production in dairy industry. Welfare and reproductive disorders data were collected by questionnaire regarding criteria of Animal Need Index (ANI – Bartussek et al., 2000) and compared by multidimensional criteria of total discriminating effect. Possibility of movement, lighting and air quality in the accommodation facility, type and quality of floor, possibility of social contacts with other cows and interaction of stockman with cattle were compared and analysed in respect of farm welfare. In respect to the welfare level of lowest ranked farm (farm 6), farms 1, 2, 3, 4, 5 and 6 were ranked as 4th, 2nd, 1st, 5th, 3rd, and 6th, respectively, but in respect to the reproductive and related disorders occurrence rate lowest ranked farm (farm 4), farms 1, 2, 3, 4, 5 and 6 were ranked as 1st, 4th, 2nd, 6th, 5th and 3rd. Discrepancy derives from the fact that reproduction data were collected for a year, while welfare assessment describes reached level in on particular moment of time, not covering all potential causes of reproductive disorders. Reduced reproductive success would seem promising as information about poor farm welfare, although good results often are not related to good welfare. Nevertheless, assessed welfare protection level provides important information about herd health and potential reproduction problems, pointing out that there are many opportunities for improving the quality of the welfare of dairy cows, mostly through improving the housing conditions of dairy cows

Comment on ``Two Time Scales and Violation of the Fluctuation-Dissipation Theorem in a Finite Dimensional Model for Structural Glasses''

In cond-mat/0002074 Ricci-Tersenghi et al. find two linear regimes in the fluctuation-dissipation relation between density-density correlations and associated responses of the Frustrated Ising Lattice Gas. Here we show that this result does not seem to correspond to the equilibrium quantities of the model, by measuring the overlap distribution P(q) of the density and comparing the FDR expected on the ground of the P(q) with the one measured in the off-equilibrium experiments.Comment: RevTeX, 1 page, 2 eps figures, Comment on F. Ricci-Tersenghi et al., Phys. Rev. Lett. 84, 4473 (2000

Uspostavljanje programa selektivnog uzgoja kalifornijske pastrmke (oncorhynchus mykiss, walbaum) u Srbiji

Zahtev za sve većim količinama hrane za ljudsku upotrebu, efikasnost iskorišćavanja hraniva i prostora za gajenje domaćih životinja, kao i pojava mnogih bolesti doveli su do intenzivnog razvijanja selekcionih programa u svim granama poljoprivrede. Za razliku od ostalih gajenih životinja, programi selekcije u akvakulturi su se razvili nešto kasnije usled nedostatka potrebnih procena heritabilnosti, koeficijenata varijacija i korelacija za ekonomski bitne osobine. Trenutno se u akvakulturi samo 1-2% od ukupne proizvodnje zasniva na genetički unapređenim vrstama riba (Gjedrem, 1997). Korišćenjem selektovanih linija riba postiže se više korisnih stvari. Na prvom mestu, programi selekcije riba predstavljaju jedini način stalnog unapređenja ekonomski bitnih osobina kao sto su prirast, konverzija hrane, otpornost na bolesti, smanjenje masnoće u mesu riba. Ribe iz selektovanih linija efikasnije iskorišćavaju hraniva i na taj način smanjuju pritisak na divlje populacije riba koje se koriste za proizvodnju ribljeg brašna, kao glavnog izvora proteina u smešama za ishranu pastrmki. Ribe koje potiču iz divljine ne napreduju zadovoljavajućim brzinom, što znači da su konstantno pod stresom, za razliku od riba poreklom iz selekcionih programa koje pokazuju manji uticaj stresa usled gajenja u zarobljeništvu. Tako se na ovaj način korišćenjem selektovanih linija riba postiže efikasna i održiva proizvodnja uz vođenje računa o dobrobiti životinja. Drugi dobar razlog za uspostavljanje programa selekcije pastrmke u Srbiji je dobro dokumentovano postojanje interakcije genotip x okolina kod kalifornijske pastrmke, kao što su pokazala istraživanja (McKay et al., 1984; Hanke et al., 1989; Sylven et al., 1991; Winkelman and Peterson, 1994; Kettunen et al., 1999; Kause et al., 2003). Na kraju, ali ne i najmanje važna je i kontrola bolesti kod kalifornijske pastrmke i mogućnost stvaranja otpornih linija pastrmki na neke bolesti putem selektivnog uzgoja (Henrion, 2005). Jedno od rešenja za ovaj ozbiljan problem, pored boljeg sistema kontrole pastrmske ikre poreklom iz uvoza, je i stvaranje lokalnih selektovanih matičnih jata sa proverenim poreklom i povećenom otpornošću na bolesti. Obzirom da za kalifornijsku pastrmku postoje pouzdani podaci o varijabilnosti i heritabilnosti proizvodnih osobina ovo pruža mogućnost efikasne selekcije, a samom tim i značajnog unapređenja proizvodnje uz smanjen ukupni mortalitet, putem odgovarajućeg programa selekcije u Srbiji

A Comparison of Papoulis and Chebyshev Filters in the Continuous Time Domain

The subject of this paper is the revisit of the Chebyshev (equiripple) and Papoulis (monotonic or staircase) low-pass filter in order to compare. It can be stated the fair comparison of Papoulis and Chebyshev filters cannot be found in the available literature. At the beginning, it is shown that ripple parameter may be used in order the Chebyshev filter to obtain a magnitude response having less passband ripple than the standard Chebyshev response. At the same time, the passband edge frequency is preserved at 3 dB. Further, the unified approach to design odd and even degree Papoulis filters is explained. For the purpose of comparison, the Chebyshev filter as a counterpart of the Papoulis filter is introduced. Thus obtained Chebyshev filter has the same stop band insertion loss, group delay and transient response as Papoulis filter. However, its passband performance is much better. It is shown that Chebyshev filter counterpart offers a better solution than Papoulis filter in all applications, except in ones applications where is required that passband attenuation to have a staircase shape

Streptozotocin-induced diabetes in the rat is associated with changes in vaginal hemodynamics, morphology and biochemical markers

BACKGROUND: Diabetes is associated with declining sexual function in women. However, the effects of diabetes on genital tissue structure, innervation and function remains poorly characterized. In control and streptozotocin-treated female rats, we investigated the effects of diabetes on vaginal blood flow, tissue morphology, and expression of arginase I, endothelial nitric oxide synthase (eNOS) and cGMP-dependent protein kinase (PKG), key enzymes that regulate smooth muscle relaxation. We further related these changes with estrogen receptor alpha (ERα) and androgen receptor (AR) expression. RESULTS: In addition to significantly elevated blood glucose levels, diabetic rats had decreased mean body weight, lower levels of plasma estradiol, and higher plasma testosterone concentration, compared to age-matched controls. Eight weeks after administration of buffer (control) or 65 mg/kg of streptozotocin (diabetic), the vaginal blood flow response to pelvic nerve stimulation was significantly reduced in diabetic rats. Histological examination of vaginal tissue from diabetic animals showed reduced epithelial thickness and atrophy of the muscularis layer. Diabetic animals also had reduced vaginal levels of eNOS and arginase I, but elevated levels of PKG, as assessed by Western blot analyses. These alterations were accompanied by a reduction in both ERα and AR in nuclear extracts of vaginal tissue from diabetic animals. CONCLUSION: In ovariectomized (estrogen deficient) animals, previous reports from our lab and others have documented changes in blood flow, tissue structure, ERα, arginase I and eNOS that parallel those observed in diabetic rats. We hypothesize that diabetes may lead to multiple disruptions in sex steroid hormone synthesis, metabolism and action. These pathological events may cause dramatic changes in tissue structure and key enzymes that regulate cell growth and smooth muscle contractility, ultimately affecting the genital response during sexual arousal