2,997 research outputs found
DDoS Attacks with Randomized Traffic Innovation: Botnet Identification Challenges and Strategies
Distributed Denial-of-Service (DDoS) attacks are usually launched through the
, an "army" of compromised nodes hidden in the network. Inferential
tools for DDoS mitigation should accordingly enable an early and reliable
discrimination of the normal users from the compromised ones. Unfortunately,
the recent emergence of attacks performed at the application layer has
multiplied the number of possibilities that a botnet can exploit to conceal its
malicious activities. New challenges arise, which cannot be addressed by simply
borrowing the tools that have been successfully applied so far to earlier DDoS
paradigms. In this work, we offer basically three contributions: we
introduce an abstract model for the aforementioned class of attacks, where the
botnet emulates normal traffic by continually learning admissible patterns from
the environment; we devise an inference algorithm that is shown to
provide a consistent (i.e., converging to the true solution as time progresses)
estimate of the botnet possibly hidden in the network; and we verify the
validity of the proposed inferential strategy over network traces.Comment: Submitted for publicatio
Split property for free massless finite helicity fields
We prove the split property for any finite helicity free quantum fields.
Finite helicity Poincar\'e representations extend to the conformal group and
the conformal covariance plays an essential role in the argument. The split
property is ensured by the trace class condition: Tr (exp(-s L_0)) is finite
for all s>0 where L_0 is the conformal Hamiltonian of the M\"obius covariant
restriction of the net on the time axis. We extend the argument for the scalar
case presented in [7]. We provide the direct sum decomposition into irreducible
representations of the conformal extension of any helicity-h representation to
the subgroup of transformations fixing the time axis. Our analysis provides new
relations among finite helicity representations and suggests a new construction
for representations and free quantum fields with non-zero helicity.Comment: v2: Minor corrections, comments and references added, as to appear in
Ann. H. Poin
Ecosystem vulnerability. New semantics for International Law
The effects of climate change and increasing environmental pollution have clearly shown the vulnerability of individuals, local communities, and the natural environment, even in the Western context. However, despite such unquestionable data, International Law is still struggling to find adequate, unambiguous, effective solutions to the issue. Even the ‘human right to a healthy environment’, recognised by the UN General Assembly in 2022, is permeated by an anthropocentric idea of the world, which prevents it from fully dealing with ecosystem issues so as to protect any living and non-living being. The paper starts by exploring the historical relevance of the concept of limit and the lack of boundaries in contemporary society, aiming to show that new semantics are needed, in order to overcome contemporary extractivism. An analysis of international legislation and jurisprudence will investigate the role that the concept of ecosystem vulnerability might play in the implementation of both human rights and the rights of nature
Plastic design of seismic resistant V-braced frames.
In this article, a new method for designing chevron concentrically braced steel frames is presented.
The aim of the proposed method is the design of concentrically braced steel frames able to
guarantee, under seismic horizontal forces, a collapse mechanism of global type. This result is of
great importance in the seismic design of structures, because local failure modes give rise to a
worsening of the energy dissipation capacity of structures and, therefore, to an higher probability
of failure during severe earthquakes. With reference to the examined structural typology, the global
mechanism is characterized by the yielding of tensile bracing diagonals and by the buckling of the
compressed diagonals of all the stories.
The proposed method is rigorously based on ‘‘capacity design approach’’ which requires that
dissipative zones have to be designed to withstand the internal actions due to the seismic design
horizontal forces and the vertical loads acting in the seismic load combination; while non
dissipative zones have to be designed considering the maximum internal actions that dissipative
zones, yielded and strain-hardened, are able to transmit. The new design issue covered by the
proposed design procedure is the need to account for the contribution of the compressed diagonals
in deriving the design axial force of non dissipative members.
The seismic inelastic response of a sample structure is investigated by means of nonlinear
dynamic analyses. The results carried out with reference to braced frames designed according to
the proposed procedure are compared with those obtained with reference to the same structural
schemes designed according to Eurocode 8
Kinetics of Thermal Decomposition of Particulate Samples of MgCO3: Experiments and Models
In this work, we study the kinetics of thermal decomposition of MgCO3 in the form of particles of known size. In the experiments, the material is heated to a known temperature in a vacuum oven, and it is characterized, both before and after heating, by infrared spectroscopy and gravimetry. The agreement between the results of the two techniques is excellent. These results are rationalized by means of a model based on Languir's law, and the comparison with the experiments allows us to estimate the activation energy of the process. The reabsorption of atmospheric water by the oxide is shown spectroscopically, finding that is strongly influenced by the temperature of the process
Cisplatin induced toxicity in rat tissues: The protective effect of Lisosan G
The protective effect of a powder of grain (Lisosan G) against cisplatin-induced toxicity in rats was studied. Male rats were fed with Lisosan G before injection of cisplatin and four days later they were killed and blood was collected along with hepatic, renal and testicular tissues. The results showed that cisplatin treatment increased plasma blood urea nitrogen, creatinine and hydrogen peroxide and decreased cytochrome P450 content in renal and hepatic tissues. It also reduced the plasmatic testosterone level and caused a depletion of testicular 17a-progesterone hydroxylase activity. In the group fed with Lisosan G and treated with cisplatin blood urea nitrogen and creatinine returned to the control level indicating a protective effect of Lisosan G. It was also observed that the ones fed with Lisosan G were able to attenuate the decrease in the P450-dependent activities and the activities of antioxidant enzymes as well. Lisosan G protected the testicular 17a-progesterone hydroxylase activity and increased the plasma testosterone level compared to animals treated only with cisplatin. Our results showed a protective effect of Lisosan G against the cisplatin induced toxicity. The protective effect of Lisosan G could be associated mainly with the attenuation of the oxidative stress and the preservation in antioxidant enzymes
Xenobiotic Metabolizing Cytocbrome P450 in Pig; a Promising Animai Model
Abstract: The pig has been used as an important animai model far human studies because of its similarity in size, physiology and disease development However, in contrast to the extensive data available on the cytochrome P450 (CYP) system far humans and rodents, the data related to pig afe limited because or, among others, the presence of intra-species differences (domestic pigs and minipigs) The knowledge of the CYP superfamily in a given experimental animaI is crucial far pharmacological and toxicological tests in developing drugs and far understanding the metaboli~ pathways of toxicants and carcinogens. In addition, information on the CYP system in pigs is Important smce Il plays a domlnant role m the metabolism of veterinary drugs, whose residues rernain in the porcine tissues which afe food far humans The aim of the present review is to examine -in the liver alId extrahepatic tissues of pig -our current knowledge of the xenobioticmetabolizing CYPs be!onging lO. famili.es 1-4, in terms of drug metabolism, substrate specificity, inhibition, gene expression and receptor- dnven regulatlon, m companson wlth human data It is hoped, furthermore, that this review may stimulate research on the porcine drug-metabollzmg enzymes morder to evaluate the hypothesis whereby pig data may better reflect human drug metabolism and toxicity than those obtained from the traditional non-rodent models. Keywords: Pig, minipig, cytochrome P450 (CYP), liver, extrahepatic tissues, animai model, xenobiotics, porcine nuclear receptors
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