351 research outputs found
SUSTAV ZA OTKRIVANJE I OBRANU KORIĹ TENJEM RUDARENJA PODATAKA
Network security helps to prevent the network against the intruders from performing malicious activities. The security can be provided to the networks using firewalls, anti-virus software and scanners, cryptographic systems, Secure Socket Layer (SSL) and Intrusion Detection Systems (IDS).Authentication is the commonly used technique to protect the unauthorized users from the network. But, it is easy to compromise the login passwords using brute force attacks. The IDS and firewalls concentrate on the external attacks, while the internal attacks are not taken into account. In order to solve these issues, this paper proposes an Inner Interruption Discovery and Defense System (IIDDS) at the System Call (SC) level using data mining and forensic techniques. The user’s profiles are maintained and compared with the actual dataset using Hellinger distance. A hash function is applied on the incoming messages and they are summarized in the sketch dataset. The experimental results evaluate the proposed system in terms of accuracy and response time.Mrežna sigurnost pomaže zaštititi mrežu od uljeza u obavljanju zlonamjernih aktivnosti. Sigurnost se može osigurati mrežama koristeći vatrozide, antivirusni softver i skenere, kriptografske sustave, Secure Socket Layer (SSL) i sustave za otkrivanje upada (IDS). Autentifikacija je najčešće korištena tehnika za zaštitu neovlaštenih korisnika na mreži. No, lako je kompromitirati lozinke za prijavu pomoću napada na silu. IDS i vatrozidi koncentriraju se na vanjske napade, dok se interni napadi ne uzimaju u obzir. Da bi se riješili ti problemi, u članku se predlaže unutarnje prekidanje i obrambeni sustav (IIDDS) na razini System Call (SC) razine pomoću rudarenja podataka i forenzičke tehnike. Profili korisnika održavaju se i uspoređuju sa stvarnim skupom podataka pomoću Hellingerove udaljenosti. Na dolazne poruke primjenjuje se hash funkcija i oni su sažeti u skupu skica podataka. Eksperimentalni rezultati procjenjuju predloženi sustav u smislu točnosti i vremena odziva
Influence of high pressure hydrogen environment on creep deformation of Mo-Re, Haynes 188, and NARloy-Z alloys
The present study focuses on the investigation of the influence of hydrogen on the mechanical properties of three types of alloys at elevated temperatures. The reasons for the consideration of hydrogen effects are the potential use of hydrogen as a coolant in gas-cooled reactors and fuel in advanced hypersonic vehicles. The materials used in hydrogen atmosphere must not be embrittled by hydrogen at ambient temperature and should have good strength in hydrogen atmosphere at elevated temperature. The paucity of information concerning the mechanical performance in hydrogen atmosphere at elevated temperature has been a limiting factor in the selection and design of structural components for operation in hydrogen environment
A Method for Efficient Calculation of Diffusion and Reactions of Lipophilic Compounds in Complex Cell Geometry
A general description of effects of toxic compounds in mammalian cells is facing several problems. Firstly, most toxic compounds are hydrophobic and partition phenomena strongly influence their behaviour. Secondly, cells display considerable heterogeneity regarding the presence, activity and distribution of enzymes participating in the metabolism of foreign compounds i.e. bioactivation/biotransformation. Thirdly, cellular architecture varies greatly. Taken together, complexity at several levels has to be addressed to arrive at efficient in silico modelling based on physicochemical properties, metabolic preferences and cell characteristics. In order to understand the cellular behaviour of toxic foreign compounds we have developed a mathematical model that addresses these issues. In order to make the system numerically treatable, methods motivated by homogenization techniques have been applied. These tools reduce the complexity of mathematical models of cell dynamics considerably thus allowing to solve efficiently the partial differential equations in the model numerically on a personal computer. Compared to a compartment model with well-stirred compartments, our model affords a more realistic representation. Numerical results concerning metabolism and chemical solvolysis of a polycyclic aromatic hydrocarbon carcinogen show good agreement with results from measurements in V79 cell culture. The model can easily be extended and refined to include more reactants, and/or more complex reaction chains, enzyme distribution etc, and is therefore suitable for modelling cellular metabolism involving membrane partitioning also at higher levels of complexity
Network structure of vertebrate scavenger assemblages at the global scale: drivers and ecosystem functioning implications
publishedVersio
Functional traits driving species role in the structure of terrestrial vertebrate scavenger networks
Species assemblages often have a non-random nested organization, which in vertebrate scavenger (carrion-consuming) assemblages is thought to be driven by facilitation in competitive environments. However, not all scavenger species play the same role in maintaining assemblage structure, as some species are obligate scavengers (i.e., vultures) and others are facultative, scavenging opportunistically. We used a database with 177 vertebrate scavenger species from 53 assemblages in 22 countries across five continents to identify which functional traits of scavenger species are key to maintaining the scavenging network structure. We used network analyses to relate ten traits hypothesized to affect assemblage structure with the role of each species in the scavenging assemblage in which it appeared. We characterized the role of a species in terms of both the proportion of monitored carcasses on which that species scavenged, or scavenging breadth (i.e., the species normalized degree), and the role of that species in the nested structure of the assemblage (i.e., the species paired nested degree), therefore identifying possible facilitative interactions among species. We found that species with high olfactory acuity, social foragers, and obligate scavengers had the widest scavenging breadth. We also found that social foragers had a large paired nested degree in scavenger assemblages, probably because their presence is easier to detect by other species to signal carcass occurrence. Our study highlights differences in the functional roles of scavenger species and can be used to identify key species for targeted conservation to maintain the ecological function of scavenger assemblages
Functional biogeography of vertebrate scavengers drives carcass removal across biomes
Resumen del trabajo presentado en el XVI Congreso Nacional de la AEET 2023: la ecologĂa en una biosfera humanizada, celebrado en AlmerĂa entre el 16 y el 20 de octubre de 2023.Vertebrate scavengers play a crucial role in food web stability and cycling of organic matter and nutrients. However, the global factors that influence their functional biogeography and impact on ecosystem functioning at regional and local levels remain poorly understood. We aim to address this challenge by analyzing a global dataset covering 49 regions in all inhabited continents, including information on 1,847 locally monitored carcasses and 204 vertebrate scavenger species along with their functional traits. We investigate the importance of biogeographical (spatial), environmental and anthropogenic factors in structuring vertebrate scavengersÂż functional trait composition, diversity and abundance. Additionally, we investigate how these biodiversity attributes affect carcass removal at regional and local scales. Our results show that the functional trait composition of assemblages across studied regions was primarily explained by latitude and lon¬gitude, suggesting a strong biogeographical signature. In addition, while functional richness remained unexplained, scavenger abundance responded to both environmental and spatial factors. Further, we found that carcass removal was mainly driven by functional composition, but with the relative importance of particular functional traits varying from local to regional scales. At the local scale, carcass removal was positively related to large carnivorous species with large home ranges, while at the regional scale, carcass removal was better explained by the presence of vultures, other raptors and diurnal birds. Our study provides a better understanding of the factors controlling the func¬tional biogeography of terrestrial vertebrates and their role in maintaining essential ecological functions and services.Peer reviewe
I just want to count them! Considerations when choosing a deer population monitoring method
Effective management of any population involves decisions based on the levels of abundance at particular points in time. Hence the choice of an appropriate method to estimate abundance is critical. Deer are not native to Australia and are a declared pest in some states where their numbers must be controlled in environmentally sensitive areas. The aim of this research was to help Australian land managers choose between widely used methods to count deer. We compared population estimates or indices from: distance sampling, aerial surveys, spotlight counts, and faecal pellet counts. For each we estimated the labour input, cost, and precision. The coefficient of variation varied with method and time of year from 8.7 to 36.6%. Total labour input per sampling event varied from 11 to 136 h. Total costs of vehicles and equipment per sampling event varied from AU2966. Overall, the spotlight method performed the best at our study site when comparing labour input, total cost and precision. However, choice of the most precise, cost effective method will be site specific and rely on information collected from a pilot study. We provide recommendations to help land managers choose between possible methods in various circumstances
Structure, conformations, and repair of DNA adducts from dibenzo [a,l]pyrene: postlabeling and fluorscense studies
The nature of stable DNA adducts derived from the very potent carcinogen dibenzo[a,l]pyrene (DB[a,l]P) in the presence of rat liver microsomes in vitro and in mouse skin in vivo has been studied usin
Migration of substituents during hydroxylation of aromatic substrates (NIH shift). Oxidations with peroxytrifluoroacetic acid
- …