4,763 research outputs found
Gamma radiation characteristics of plutonium dioxide fuel
Net gamma ray source intensity and spectrum for plutonium dioxide fuel element
Physics case of the very high energy electron--proton collider, VHEeP
The possibility of a very high energy electron-proton (VHEeP) collider with a
centre-of-mass energy of 9 TeV has been presented at previous workshops. These
proceedings briefly summarise the VHEeP concept, which was recently published,
and developments since then, as well as future directions. At the VHEeP
collider, with a centre-of-mass energy 30 times greater than HERA, parton
momentum fractions, , down to about are accessible for photon
virtualities, , of 1 GeV. This extension in the kinematic range to low
complements proposals for other electron-proton or electron-ion colliders.Comment: 6 pages, 2 figures, for proceedings of DIS 2017 worksho
Activities of the RTG Radiation Test Laboratory Progress report, 1 Jul. - 31 Dec. 1969
Safety, gamma ray spectrum, and data analysis of SNAP fuel capsule
Relations Among Type 2 Diabetes, Arterial Stiffness and Cognitive Functioning
Although the associations among diabetes mellitus, cognitive functioning and arterial stiffness have been explored previously, the degree to which arterial stiffness is responsible for the association between diabetes and cognitive function has not been examined. The primary aim of the current investigations is to examine the extent to which arterial stiffness mediates the association between diabetes and cognitive function, as well as the extent to which this indirect effect is modified by age and APOE genotype. The sample included 590 participants (age 23-94, 62% women, 12% African- American) from the seventh wave of the Maine-Syracuse Longitudinal Study. Individuals with history of stroke, probable dementia, and PWV error of estimate \u3e0.20 were excluded. Diabetes was defined as elevated glucose or treatment. Pulse wave velocity was used to as an indirect measure of arterial stiffness. Multiple statistical methods were used to examine the association between diabetes and cognitive function, as well as between PWV and cognitive function. Then, path analysis was used to examine the direct and indirect (through PWV) associations between diabetes and cognitive function. With adjustment for demographic and CVD risk variables, associations between diabetes and multiple measures of cognitive ability were observed for the APOE-ε4 carriers only. PWV was related to multiple cognitive measures, and this association was modified by age such that the lowest performance was observed in older individuals with elevated PWV. When diabetes, PWV and cognitive function were included together in the analysis of paths between variables, an indirect association between diabetes and cognitive function through PWV was observed, such that diabetes related to higher PWV, and lower cognitive function in older APOE-ε4 carriers. These findings may have important clinical implications with regard to attenuating the pronounced association between diabetes and cognitive function observed for persons who carry the APOE-ε4 allele. Accelerated arterial stiffness may possibly be treated by the same methods that are used to treat hypertension. Clinical trials are necessary to determine if modification of levels of PWV by drugs and other treatments will lead to an improvement in cognitive performance. Treatment specific to APOE genotype are also a possibility
Effect of Al doping on the optical phonon spectrum in Mg(1-x)Al(x)B(2)
Raman and infrared absorption spectra of Mg(1-x)Al(x)B(2) have been collected
for 0<x<0.5 in the spectral range of optical phonons. The x-dependence of the
peak frequency, the width and the intensity of the observed Raman lines has
been carefully analized. A peculiar x-dependence of the optical modes is
pointed out for two different Al doping ranges. In particular the onset of the
high-doping structural phase previously observed in diffraction measurements is
marked by the appearence of new spectral components at high frequencies. A
connection between the whole of our results and the observed suppression of
superconductivity in the high doping region is established
OPTIMIZATION OF TWO FISH ENCRYPTION ALGORITHM ON FPGA
The demand for efficient and secure ciphers has given rise to a new generation of block ciphers
capable of providing increased protection at lower cost. Among these new algorithms is Twofish.
Twofish is a promising 128-bit block which was one of the 5 finalists in the National Institute of
Standards and Technology organized competition as the Advanced Encryption Standard. The aim
of the competition was to find a suitable candidate to replace DES at the core of many encryption
systems worldwide.
Twofish can work with variable key lengths: 128, 192 or 256 bits. In this report, only a version of
128-bit key length was discussed. Twofish has 6 main building blocks; Feistel Networks,
whitening, S-boxes, MDS Matrices, Pseudo Hadamard Transforms and Key Schedule. Twofish is
a 16 round Feistel network with a bijective F function, which corresponds to 8 cycles. The
whitening technique employed substantially increases the difficulty of keysearch attacks against
the remainder of the cipher. Twofish uses 4 different, bijective, key-dependent, 8-by-8 bit Sboxes.
Twofish uses a single 4 by 4 MDS matrix over GF (28).This is one of the 2 main diffusion
elements of Two fish. There is also Reed-Solomon code with the MDS property used in the key
schedule; this doesn't add diffusion to the cipher but does add diffusion to the key schedule.)
Besides that, Twofish also uses a 32 bit Pseudo Hadamard Transform to mix the outputs from its
2 parallel 32-bit g functions. Finally, Twofish needs a lot of key material, and has complicated
key schedule. To facilitate analysis, the key schedule uses the same primitives as the round
function. Except for 2 additional rotations, each pair of expanded key words is constructed by
applying the Twofish round function (with key-dependent).
For this project, 2 different optimized designs were implemented. The first design
(Design I) was implemented with minimum hardware resources usage, using a single F -Function
(modified) and was optimized with reasonable latency, throughput and throughput per gate. As
for the second design (Design 2) was implemented with reasonably minimum hardware resources
using 4 units of F-Function(modified) of Design I, minimum hardware resources usage, very
small latency, very high throughput and very high throughput per gate. Furthermore, both Design
I and Design 2 were implemented with zero keying and function as encryptor/decryptor. Both
Design I and Design 2 were written using VHDL, simulated using ALDEC, synthesized using
XILINX Synthesizing Tools, implemented using XILINX ISE6.2i implementation tools and
download onto the Spartan 2 FPGA board using BEDLOAD utility program.
As a conclusion this Final Year Project is quite successful because all the objectives have
been met successfull
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