750 research outputs found
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Scale Inside-Out: Rapid Mitigation of Cloud DDoS Attacks
The distributed denial of service (DDoS) attacks in cloud computing requires quick absorption of attack data. DDoS attack mitigation is usually achieved by dynamically scaling the cloud resources so as to quickly identify the onslaught features to combat the attack. The resource scaling comes with an additional cost which may prove to be a huge disruptive cost in the cases of longer, sophisticated, and repetitive attacks. In this work, we address an important problem, whether the resource scaling during attack, always result in rapid DDoS mitigation? For this purpose, we conduct real-time DDoS attack experiments to study the attack absorption and attack mitigation for various target services in the presence of dynamic cloud resource scaling. We found that the activities such as attack absorption which provide timely attack data input to attack analytics, are adversely compromised by the heavy resource usage generated by the attack. We show that the operating system level local resource contention, if reduced during attacks, can expedite the overall attack mitigation. The attack mitigation would otherwise not be completed by the dynamic scaling of resources alone. We conceived a novel relation which terms “Resource Utilization Factor” for each incoming request as the major component in forming the resource contention. To overcome these issues, we propose a new “Scale Inside-out” approach which during attacks, reduces the “Resource Utilization Factor” to a minimal value for quick absorption of the attack. The proposed approach sacrifices victim service resources and provides those resources to mitigation service in addition to other co-located services to ensure resource availability during the attack. Experimental evaluation shows up to 95 percent reduction in total attack downtime of the victim service in addition to considerable improvement in attack detection time, service reporting time, and downtime of co-located services
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DDoS victim service containment to minimize the internal collateral damages in cloud computing
Recent Distributed Denial of Service (DDoS) attacks on cloud services demonstrate new attack effects, including collateral and economic losses. In this work, we show that DDoS mitigation methods may not provide the expected timely mitigation due to the heavy resource outage created by the attacks. We observe an important Operating System (OS) level internal collateral damage, in which the other critical services are also affected. We formulate the DDoS mitigation problem as an OS level resource management problem. We argue that providing extra resources to the victim's server is only helpful if we can ensure the availability of other services. To achieve these goals, we propose a novel resource containment approach to enforce the victim's resource limits. Our real-time experimental evaluations show that the proposed approach results in reduction in the attack reporting time and victim service downtime by providing isolated and timely resources to ensure availability of other critical services
First measurement of the Head-Tail directional nuclear recoil signature at energies relevant to WIMP dark matter searches
We present first evidence for the so-called Head-Tail asymmetry signature of
neutron-induced nuclear recoil tracks at energies down to 1.5 keV/amu using the
1m^3 DRIFT-IIc dark matter detector. This regime is appropriate for recoils
induced by Weakly Interacting Massive Particle (WIMPs) but one where the
differential ionization is poorly understood. We show that the distribution of
recoil energies and directions induced here by Cf-252 neutrons matches well
that expected from massive WIMPs. The results open a powerful new means of
searching for a galactic signature from WIMPs.Comment: 4 pages, 6 figures, 1 tabl
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Combating DDoS attacks in the cloud: Requirements, trends, and future directions
An overview of DDoS attacks against cloud targets is presented, together with solution requirements, and a guideline for efficient solutions, leading to a novel multilevel alert-flow. To orchestrate future solutions, we give a vision towards novel "Detection Near Impossible" attacks
A technical evaluation of improved animal drawn implements under on-farm conditions
Animals are a major source of agriculture power in India and animal drawn implements have evolved to a high degree of simplicity and perfection over a long period of time..
A Preliminary Observational Search for Circumbinary Disks Around Cataclysmic Variables
Circumbinary (CB) disks have been proposed as a mechanism to extract orbital
angular momentum from cataclysmic variables (CVs) during their evolution. As
proposed by Taam & Spruit, these disks extend outwards to several a.u. and
should be detected observationally via their infrared flux or by absorption
lines in the ultraviolet spectra of the CV. We have made use of archival
HST/STIS spectra as well as our own near-IR imaging to search for observational
evidence of such CB disks in seven CVs. Based on the null result, we place an
upper limit on the column density of the disk of N_H~10^17 cm^-2.Comment: accepted for publication in the Astronomical Journal (July 2004
Acceptability and adherence to a Mediterranean diet in the postnatal period to prevent type 2 diabetes in women with gestational diabetes in the UK: a protocol for a single-arm feasibility study (MERIT)
Introduction: Women with gestational diabetes are at increased risk of developing type 2 diabetes later in life. In at-risk general populations, Mediterranean-style diet helps prevent type 2 diabetes. But its effect on postnatal women with a history of gestational diabetes is not known. Prior to a full-scale trial on Mediterranean-style diet in the postnatal period to prevent type 2 diabetes, a feasibility study is required to assess the acceptability of the diet and evaluate the trial processes.
Methods and analysis: MEditerranean diet for pReventIon of type 2 diabeTes is a single-arm feasibility study (65 women) with qualitative evaluation of women who have recently given birth and had gestational diabetes. The intervention is a Mediterranean-style diet supplemented with nuts and olive oil, with dietary advice and an action plan. A dedicated Health Coach will interact with participants through an interactive lifestyle App. Women will follow the intervention from 6 to 13 weeks post partum until 1 year post partum. The primary outcomes are rates of recruitment, follow-up, adherence and attrition. The secondary outcomes are maternal dysglycaemia, cost and quality of life outcomes, and acceptability of the intervention to participants, and to healthcare professionals delivering the intervention. Feasibility outcomes will be reported using descriptive statistics.
Ethics and dissemination: Ethical approval was obtained through the South Central—Berkshire Research Ethics Committee (19/SC/0064). Study findings will be disseminated via publication in peer-reviewed journals, as well as via newsletters made available to participants and members of Katie’s Team (a women’s health patient and public advisory group).
Trial registration number: ISRCTN40582975
Measurement of B(Ds+ -->ell+ nu) and the Decay Constant fDs From 600/pb of e+e- Annihilation Data Near 4170 MeV
We examine e+e- --> Ds^-D_s^{*+} and Ds^{*-}Ds^{+} interactions at 4170 MeV
using the CLEO-c detector in order to measure the decay constant fDs with good
precision. Previously our measurements were substantially higher than the most
precise lattice based QCD calculation of (241 +/- 3) MeV. Here we use the D_s^+
--> ell^+ nu channel, where the ell^+ designates either a mu^+ or a tau^+, when
the tau^+ --> pi^+ anti-nu. Analyzing both modes independently, we determine
B(D_s^+ --> mu^+ nu)= 0.565 +/- 0.045 +/- 0.017)%, and B(D_s^+ --> mu^+ nu)=
(6.42 +/- 0.81 +/- 0.18)%. We also analyze them simultaneously to find an
effective value of B^{eff}(D_s^+ --> mu^+ nu)= (0.591 +/- 0.037 +/- 0.018)% and
fDs=(263.3 +/- 8.2 +/- 3.9) MeV. Combining with the CLEO-c value determined
independently using D_s^+ --> tau^+ nu, tau^+ --> e^+ nu anti-nu decays, we
extract fDs=(259.5 +/- 6.6 +/- 3.1) MeV. Combining with our previous
determination of B(D^+ --> mu^+ nu), we extract the ratio fDs/fD+=1.26 +/- 0.06
+/- 0.02. No evidence is found for a CP asymmetry between Gamma(D_s^+ -->
mu^+\nu) and \Gamma(D_s^- --> mu^- nu); specifically the fractional difference
in rates is measured to be (4.8 +/- 6.1)%. Finally, we find B(D_s^+ --> e^+ nu)
< 1.2x10^{-4} at 90% confidence level.Comment: 26 pages, 16 figure
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