On the role of mobility and hunting effectiveness in a prey-predator model

Abstract.: We present a new, extended, predator-prey model for which we discuss the role of predators mobility and hunting effectiveness on the dynamics of the system. We show, via Monte Carlo simulations, that the maximum of predators' population density is a rather complex function of both - mobility and effectiveness of hunting. For a low mobility, larger effectiveness suits the predators better. When the mobility is large, the predators population is bigger if the predators are rather bad hunters. We have not observed temporal oscillations in the densities of both specie

How bad is to be slow-reacting?: On the effect of the delay in response to a changing environment on a population's survival

We consider a simple-model population, whose individuals react with a certain delay to temporal variations of their habitat. We investigate the impact of such a delayed-answer on the survival chances of the population, both in a periodically changing environment, and in the case of an abrupt change of it. It is found that for populations with low degree of mutation-induced variability, being "slow-reacting” decreases the extinction risk due to environmental changes. On the contrary, for populations with high mutation amplitude, the delayed reaction reduces the survival chance

Model of evolution with sexual and non-sexual reproduction

Using a previously introduced model (Refs. [9, 10]) of biological evolution, we study the role of the reproduction pattern on the fate of an evolving population. Each individual is under the selectional pressure from the environment and random harmful mutations. The habitat ("climate") is changing periodically. Evolution of populations following three reproduction patterns are compared -an asexual one (without recombination) and two with recombination -asexual (meiotic parthenogenesis) and sexual. We show, via Monte-Carlo simulations, that sexual reproduction leads to a better adaptation to the environment, slightly better survival rates for the individuals and higher probability that the population will not become extinct in difficult external conditions. The benefits of sexual reproduction are enhanced by higher birth rates and lower mutation rates. In the case of low birth rates and high mutation rates there is a small preference for the meiotic parthenogenesis

Effect of eugenics on the evolution of populations

We discuss a model of population dynamics under selection pressure from a changing environment. The population, subject to mutations, is composed of diploidal organisms reproducing quasi-sexually (two parents, recombination but no sexes) and with overlapping generations. Two cases are considered -in one we do not influence the dynamics of the population, while in the other we perform eugenics, i.e. we eliminate all individuals which have phenotypes not conforming to the optimal one at the place where the change has been made. We show that eugenics reduces greatly genetic diversity of the population, increases the percentage of homozygotes and therefore leads to a population badly prepared to cope with the next changes of the environment. The present paper is an extension of our previous work (Ref. [9])

Implementation of Standardized Cooperation Environment for Intelligent Transport Systems

Many of Intelligent Transport Systems (ITS) solutions are using components that dynamically change in time and space. Among these, there occur changes of location, movement parameters, components configuration, external environment influence, automation use, etc. Standard facilities in ITS communication model are useful base for implementation of the services in such variable environment. Such features have an influence on the implementation of the services and requirements for the lower communication layers

Mobile testing lab of electronic communication services functions and quality

Artykuł opisuje projekt w ramach którego zaprojektowano mobilne laboratorium badawcze, które zostało wykonane przez Instytut Łączności we współpracy z Wojskowymi Zakładami Łączności Nr 1 w Zegrzu. Opisano zakres zastosowań i przeznaczenie takiej jednostki, funkcjonalność metrologiczną, wyposażenie w aparaturę pomiarową i możliwości eksploatacyjne. W dalszej części publikacji opisano przebieg realizacji projektu oraz uzyskane wyniki.The paper describes a project oriented on mobile lab development, made by National Institute of Telecommunication in cooperation with Military Communication Works no 1 S.A. It was described applicability and targets of the unit, metrological functionality, measurement equipment and operational capabilities. Project execution process and results was also described

Model of populations colonizing a new habitat

We propose a model suitable for investigating the conditions under which a population, adapted to a given environment, may colonize a new neighbouring, spatially separated, habitat. We find out how similar the two regions must be for such a colonization to succeed and what will be the spatial distribution of genetic pools of the two populations after the process. It is found that between the two populations each adapted to the different region, a hybrid zone, characterized by increased heterozygosity, may be formed. The dependence of the shape of the hybrid zone on the external (environmental) parameters is determined. When the differences between the two regions are significant, the populations are separated by a depopulated zone. We show that the conditions in the colonized habitat influence the genetic pool of the population living in the first region. Computer simulations based on the standard Monte Carlo technique are used

Intelligent transport systems (ITS) interoperability assurance drivers

Interoperability is one of crucial problems in transport systems and it is touching especially the systems, when their complexity is growing with application of information and communications techniques. Directive of 2010/40/ EU on frameworks of the implementation of intelligent transport systems in the area of the road transport and interfaces with other types of transport has established measures to ensure ITS conformance, interoperability and continuity. Here there is review of the drivers to ITS interoperability achievement, as well as processes of their practical application. Special focus is on testing of the implementation of standards and the specifications

National ITS architecture objectives

Architecture of Intelligent Transport Systems (ITS) is a set of general statements which let to plan unified implementation of applications and services, cooperating with each other. Due to formal and practical requirements it should be architecture fulfilling domestic conditions, including public language. The collected knowledge, experience and studies, particularly connected with European Frame ITS architecture, can be a useful start point both to drawing up Polish domestic ITS architecture, as well as to adopting institutional arrangements, allowing for her effective applications and wide approval

Material and repair problems in brown coal excavator buckets

Dobór materiałów na czerpaki koparek węgla brunatnego jest od początku konstrukcji tych maszyn jednym z podstawowych czynników limitujących ich możliwości wydobywcze. Trwałość poszczególnych elementów w zróżnicowanych warunkach wydobycia wykazuje duże rozrzuty i zależy nie tylko od rozwiązań konstrukcyjnych ale także od rodzajów zastosowanych materiałów, ich obróbki cieplnej, podwyższania własności warstw powierzchniowych i technologii łączenia. W pracy przedstawiono dane dotyczące trwałości poszczególnych części czerpaka, zakresy, częstotliwość i czasochłonność prac remontowych w powiązaniu ze stosowanymi rozwiązaniami materiałowymi. Na podstawie wyników prac badawczych wykonywanych głównie na Wydziale Mechanicznym Politechniki Wrocławskiej wskazano i uzasadniono przyczyny zużywania i uszkodzeń. Rezultaty tych prac umożliwiły także przedstawienie własnych propozycji dotyczących modyfikacji rozwiązań materiałowych mogących podwyższać własności eksploatacyjne tego zespołu konstrukcyjnego koparek. Sugestią autorów jest przeprowadzenie prób w warunkach eksploatacyjnych czerpaków wykonanych z zaproponowanych materiałów.Since the very beginnings of the brown coal excavator building the selection of materials for their buckets has been one of the main factors limiting their mining capacities. Lives of particular parts in the variable mining conditions show high scatter and depend not only on the design solutions but also the types of materials applied, their heat treatments, improvement of their superficial layers and joining technology. In the work the data concerning durability of particular bucket parts, scopes, frequencies and time consumption of the repair works, in connection with the applied material solutions, have been presented. Based at the results of research performed mainly at the Mechanical Engineering Faculty of the Wrocław University of Technology the reasons for their wear and failure have been shown and justified. Results of the works enabled also presentation of our own proposals concerning modification of material solutions aimed at improving the operational properties of that excavator assembly. The Authors suggest trial runs of the buckets made of the proposed materials in the normal operating conditions