373 research outputs found
Improving Intrusion Prevention, Detection and Response
Merged with duplicate record 10026.1/479 on 10.04.2017 by CS (TIS)In the face of a wide range of attacks. Intrusion Detection Systems (IDS) and other Internet
security tools represent potentially valuable safeguards to identify and combat the problems
facing online systems. However, despite the fact that a variety o f commercial and open source
solutions are available across a range of operating systems and network platforms, it is notable
that the deployment of IDS is often markedly less than other well-known network security
countermeasures and other tools may often be used in an ineffective manner.
This thesis considers the challenges that users may face while using IDS, by conducting a web-based
questionnaire to assess these challenges. The challenges that are used in the questionnaire
were gathered from the well-established literature. The participants responses varies between
being with or against selecting them as challenges but all the listed challenges approved that
they are consider problems in the IDS field.
The aim of the research is to propose a novel set of Human Computer Interaction-Security
(HCI-S) usability criteria based on the findings of the web-based questionnaire. Moreover,
these criteria were inspired from previous literature in the field of HCI. The novelty of the
criteria is that they focus on the security aspects. The new criteria were promising when they
were applied to Norton 360, a well known Internet security suite. Testing the alerts issued by
security software was the initial step before testing other security software. Hence, a set of security software were selected and some alerts were triggered as a result of performing a
penetration test conducted within a test-bed environment using the network scanner Nmap. The
findings reveal that four of the HCI-S usability criteria were not fully addressed by all of these
security software.
Another aim of this thesis is to consider the development of a prototype to address the HCI-S
usability criteria that seem to be overlooked in the existing security solutions. The thesis
conducts a practical user trial and the findings are promising and attempt to find a proper
solution to solve this problem. For instance, to take advantage of previous security decisions, it
would be desirable for a system to consider the user's previous decisions on similar alerts, and
modify alerts accordingly to account for the user's previous behaviour. Moreover, in order to
give users a level of fiexibility, it is important to enable them to make informed decisions, and
to be able to recover from them if needed. It is important to address the proposed criteria that
enable users to confirm / recover the impact of their decision, maintain an awareness of system
status all the time, and to offer responses that match users' expectations.
The outcome of the current study is a set of a proposed 16 HCI-S usability criteria that can be
used to design and to assess security alerts issued by any Internet security suite. These criteria
are not equally important and they vary between high, medium and low.The embassy of the arab republic of Egypt (cultural centre & educational bureau) in Londo
Chen ranks and resonance
The Chen groups of a group are the lower central series quotients of the
maximal metabelian quotient of . Under certain conditions, we relate the
ranks of the Chen groups to the first resonance variety of , a jump locus
for the cohomology of . In the case where is the fundamental group of
the complement of a complex hyperplane arrangement, our results positively
resolve Suciu's Chen ranks conjecture. We obtain explicit formulas for the Chen
ranks of a number of groups of broad interest, including pure Artin groups
associated to Coxeter groups, and the group of basis-conjugating automorphisms
of a finitely generated free group.Comment: final version, to appear in Advances in Mathematic
Cohomological dimension and arithmetical rank of some determinantal ideals
Let be a non-generic matrix of linear forms in a
polynomial ring. For large classes of such matrices, we compute the
cohomological dimension (cd) and the arithmetical rank (ara) of the ideal
generated by the -minors of . Over an algebraically closed
field, any -matrix of linear forms can be written in the
Kronecker-Weierstrass normal form, as a concatenation of scroll, Jordan and
nilpotent blocks. B\u{a}descu and Valla computed when
is a concatenation of scroll blocks. In this case we compute
and extend these results to concatenations of Jordan
blocks. Eventually we compute and
in an interesting mixed case, when contains both Jordan and scroll blocks.
In all cases we show that is less than the arithmetical
rank of the determinantal ideal of a generic matrix
Heterogeneous processes: Laboratory, field, and modeling studies
The efficiencies of chemical families such as ClO(x) and NO(x) for altering the total abundance and distribution of stratospheric ozone are controlled by a partitioning between reactive (active) and nonreactive (reservoir) compounds within each family. Gas phase thermodynamics, photochemistry, and kinetics would dictate, for example, that only about 1 percent of the chlorine resident in the lower stratosphere would be in the form of active Cl or ClO, the remainder existing in the reservoir compounds HCl and ClONO2. The consistency of this picture was recently challenged by the recognition that important chemical transformations take place on polar regions: the Airborne Antarctic Ozone Experiment (AAOE) and the Airborne Arctic Stratospheric Expedition (AASA). Following the discovery of the Antarctic ozone hole, Solomon et al. suggested that the heterogeneous chemical reaction: ClONO2(g)+HCl(s) yields Cl2(g)+HNO3(s) could play a key role in converting chlorine from inactive forms into a species (Cl2) that would rapidly dissociate in sunlight to liberate atomic chlorine and initiate ozone depletion. The symbols (s) and (g) denote solid phase, or adsorbed onto a solid surface, and gas phase, respectively, and represent the approach by which such a reaction is modeled rather than the microscopic details of the reaction. The reaction was expected to be most important at altitudes where PSC's were most prevalent (10 to 25 km), thereby extending the altitude range over which chlorine compounds can efficiently destroy ozone from the 35 to 45 km region (where concentrations of active chlorine are usually highest) to lower altitudes where the ozone concentration is at its peak. This chapter will briefly review the current state of knowledge of heterogeneous processes in the stratosphere, emphasizing those results obtained since the World Meteorological Organization (WMO) conference. Sections are included on laboratory investigations of heterogeneous reactions, the characteristics and climatology of PSC's, stratospheric sulfate aerosols, and evidence of heterogeneous chemical processing
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