5,817 research outputs found
Cloud Security
Isabella Roth
Jose Salazar
Professor Yi Hu
Computer Information Technology
Cloud Security: AWS Abstract
With enterprises moving their IT infrastructure to the cloud using providers like Amazon Web Services (AWS), security problems have not been reduced. In fact, cloud computing brings new security challenges. Our research investigated better solutions to the security problems that come with using the cloud to store a companies data.
The cloud is a general term for using the internet to receive some sort of data vs connecting directly to a server. This makes it easier to do things such as connecting to an online app to even retrieving information about your company such as the statics on all of the employs in your workplace. Storing information in the cloud is a lot cheaper than using a server to store certain information. Of course, however, it is relatively harder to secure and implement the cloud in the workforce. So we investigated which cloud solution would be easiest to implement in a workplace environment. We spent most of the summer working towards getting the cloud to communicate with a simple app we had created. This app would then use a third party, such as Facebook to verify and log you into the app. Due to the limited experience, we had when we began this project we had to fail many a time until we finally succeeded. I hope in the future we are able to explore more deeply into more complex versions of cloud security
Computer-assisted polyp matching between optical colonoscopy and CT colonography: a phantom study
Potentially precancerous polyps detected with CT colonography (CTC) need to
be removed subsequently, using an optical colonoscope (OC). Due to large
colonic deformations induced by the colonoscope, even very experienced
colonoscopists find it difficult to pinpoint the exact location of the
colonoscope tip in relation to polyps reported on CTC. This can cause unduly
prolonged OC examinations that are stressful for the patient, colonoscopist and
supporting staff.
We developed a method, based on monocular 3D reconstruction from OC images,
that automatically matches polyps observed in OC with polyps reported on prior
CTC. A matching cost is computed, using rigid point-based registration between
surface point clouds extracted from both modalities. A 3D printed and painted
phantom of a 25 cm long transverse colon segment was used to validate the
method on two medium sized polyps. Results indicate that the matching cost is
smaller at the correct corresponding polyp between OC and CTC: the value is 3.9
times higher at the incorrect polyp, comparing the correct match between polyps
to the incorrect match. Furthermore, we evaluate the matching of the
reconstructed polyp from OC with other colonic endoluminal surface structures
such as haustral folds and show that there is a minimum at the correct polyp
from CTC.
Automated matching between polyps observed at OC and prior CTC would
facilitate the biopsy or removal of true-positive pathology or exclusion of
false-positive CTC findings, and would reduce colonoscopy false-negative
(missed) polyps. Ultimately, such a method might reduce healthcare costs,
patient inconvenience and discomfort.Comment: This paper was presented at the SPIE Medical Imaging 2014 conferenc
The mechanism of the polarization dependence of the optical transmission in subwavelength metal hole arrays
We investigate the mechanism of extraordinary optical transmission in
subwave-length metal hole arrays. Experimental results for the arrays
consisting of square or rectangle holes are well explained about the dependence
of transmission strength on the polarization direction of the incident light.
This polarization dependence occurs in each single-hole. For a hole array,
there is in addition an interplay between the adjacent holes which is caused by
the transverse magnetic field of surface plasmon polariton on the metal film
surfaces. Based on the detailed study of a single-hole and two-hole structures,
a simple method to calculate the total tranmissivity of hole arrays is
proposed.Comment: 34 pages, 7 figure
Complementary tuning of Na+ and K+ channel gating underlies fast and energy-efficient action potentials in GABAergic interneuron axons
Fast-spiking, parvalbumin-expressing GABAergic interneurons (PV+-BCs) express a complex machinery of rapid signaling mechanisms, including specialized voltage-gated ion channels to generate brief action potentials (APs). However, short APs are associated with overlapping Na+ and K+ fluxes and are therefore energetically expensive. How the potentially vicious combination of high AP frequency and inefficient spike generation can be reconciled with limited energy supply is presently unclear. To address this question, we performed direct recordings from the PV+-BC axon, the subcellular structure where active conductances for AP initiation and propagation are located. Surprisingly, the energy required for the AP was, on average, only ∼1.6 times the theoretical minimum. High energy efficiency emerged from the combination of fast inactivation of Na+ channels and delayed activation of Kv3-type K+ channels, which minimized ion flux overlap during APs. Thus, the complementary tuning of axonal Na+ and K+ channel gating optimizes both fast signaling properties and metabolic efficiency. Hu et al. demonstrate that action potentials in parvalbumin-expressing GABAergic interneuron axons are energetically efficient, which is highly unexpected given their brief duration. High energy efficiency emerges from the combination of fast inactivation of voltage-gated Na+ channels and delayed activation of Kv3 channels in the axon
Finite temperature effects on the collapse of trapped Bose-Fermi mixtures
By using the self-consistent Hartree-Fock-Bogoliubov-Popov theory, we present
a detailed study of the mean-field stability of spherically trapped Bose-Fermi
mixtures at finite temperature. We find that, by increasing the temperature,
the critical particle number of bosons (or fermions) and the critical
attractive Bose-Fermi scattering length increase, leading to a significant
stabilization of the mixture.Comment: 5 pages, 4 figures; minor changes, proof version, to appear in Phys.
Rev. A (Nov. 1, 2003
Mean-field analysis of the stability of a K-Rb Fermi-Bose mixture
We compare the experimental stability diagram of a Fermi-Bose mixture of K-40
and Rb-87 atoms with attractive interaction to the predictions of a mean-field
theoretical model. We discuss how this comparison can be used to give a better
estimate of the interspecies scattering length, which is currently known from
collisional measurements with larger uncertainty.Comment: 5 pages, 4 figure
Expansion of the ADOR strategy for the synthesis of new zeolites : the synthesis of IPC-12 from zeolite UOV
R.E.M. thanks the Royal Society and the Engineering and Physical Sciences Research Council (Grants EP/K025112/1, EP/K005499/1, EP/L016419/1) for funding work in this area and for providing a Ph.D. studentship to S.E.R. through the Criticat Centre for Doctoral training. R.E.M. and M. O. acknowledge the OP VVV "Excellent Research Teams", project No. CZ.02.1.01/0.0/0.0/15_003/0000417 - CUCAM. J.Č., V.K., and M.T. acknowledge the Czech Science Foundation for the project of the Centre of Excellence (P106/12/G015) and J.Č has received funding from the European Union's Horizon2020 research and innovation programme under grant agreement No 640979. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement No. 312483—ESTEEM2 (Integrated Infrastructure Initiative–I3).The assembly-disassembly-organization-reassembly (ADOR) process has been used to disassemble a parent zeolite with the UOV structure type and then reassemble the resulting layers into a novel structure, IPC-12. The structure of the material has previously been predicted computationally and confirmed in our experiments using X-ray diffraction and atomic resolution STEM-HAADF electron microscopy. This is the first successful application of the ADOR process to a material with porous layers.Publisher PDFPeer reviewe
DREADD: A Chemogenetic GPCR Signaling Platform
Recently, we created a family of engineered G protein-coupled receptors (GPCRs) called DREADD (designer receptors exclusively activated by designer drugs) which can precisely control three major GPCR signaling pathways (Gq, Gi, and Gs). DREADD technology has been successfully applied in a variety of in vivo studies to control GPCR signaling, and here we describe recent advances of DREADD technology and discuss its potential application in drug discovery, gene therapy, and tissue engineering
Pressure-induced chemistry for the 2D to 3D transformation of zeolites
M.M., P.S.W., G.P.M.B., S.E.A., and R.E.M. thank the EPSRC (grants: EP/K025112/1, EP/L014475/1, and EP/ M506631/1) for funding. M.M., P.N., J.Č. and R.E.M. would like to acknowledge OP VVV "Excellent Research Teams", project No. CZ.02.1.01/0.0/0.0/15_003/0000417 - CUCAM. J.Č. and P.N. acknowledge the Czech Science Foundation (P106/12/G015) for the financial support of this research. J.P.A. acknowledges EPSRC support for the high pressure work.ADOR, an unconventional synthesis strategy based on a four-step mechanism: assembly, disassembly, organization, and reassembly, has opened new possibilities in zeolite chemistry. The ADOR approach led to the discovery of the IPC family of materials with tuneable porosity. Here we present the first pressure-induced ADOR transformation of 2D zeolite precursor IPC-1P into fully crystalline 3D zeolite IPC-2 (OKO topology) using a Walker-type multianvil apparatus under a pressure of 1 GPa at 200 °C. Surprisingly, the high-pressure material is of lower density (higher porosity) than the product obtained from simply calcining the IPC-1P precursor at high temperature, which produces IPC-4 (PCR topology). The sample was characterized by PXRD, 29Si MAS NMR, SEM, and HRTEM. Theoretical calculations suggest that high pressure can lead to the preparation of other ADOR zeolites that have not yet been prepared.PostprintPostprintPeer reviewe
Bose - Einstein Condensate Superfluid-Mott Insulator Transition in an Optical Lattice
We present in this paper an analytical model for a cold bosonic gas on an
optical lattice (with densities of the order of 1 particle per site) targeting
the critical regime of the Bose - Einstein Condensate superfluid - Mott
insulator transition. We focus on the computation of the one - body density
matrix and its Fourier transform, the momentum distribution which is directly
obtainable from `time of flight'' measurements. The expected number of
particles with zero momentum may be identified with the condensate population,
if it is close to the total number of particles. Our main result is an analytic
expression for this observable, interpolating between the known results valid
for the two regimes separately: the standard Bogoliubov approximation valid in
the superfluid regime and the strong coupling perturbation theory valid in the
Mott regime.Comment: 40 pages, 6 figure
- …