381 research outputs found
Supporting security-oriented, collaborative nanoCMOS electronics research
Grid technologies support collaborative e-Research typified by multiple institutions and resources seamlessly shared to tackle common research problems. The rules for collaboration and resource sharing are commonly achieved through establishment and management of virtual organizations (VOs) where policies on access and usage of resources by collaborators are defined and enforced by sites involved in the collaboration. The expression and enforcement of these rules is made through access control systems where roles/privileges are defined and associated with individuals as digitally signed attribute certificates which collaborating sites then use to authorize access to resources. Key to this approach is that the roles are assigned to the right individuals in the VO; the attribute certificates are only presented to the appropriate resources in the VO; it is transparent to the end user researchers, and finally that it is manageable for resource providers and administrators in the collaboration. In this paper, we present a security model and implementation improving the overall usability and security of resources used in Grid-based e-Research collaborations through exploitation of the Internet2 Shibboleth technology. This is explored in the context of a major new security focused project at the National e-Science Centre (NeSC) at the University of Glasgow in the nanoCMOS electronics domain
Federated authentication and authorisation for e-science
The Grid and Web service community are defining a range of standards for a complete solution for security. The National e-Science Centre (NeSC) at the University of Glasgow is investigating how the various pre-integration components work together in a variety of e-Science projects. The EPSRC-funded nanoCMOS project aims to allow electronics designers and manufacturers to use e-Science technologies and expertise to solve problems of device variability and its impact on system design. To support the security requirements of nanoCMOS, two NeSC projects (VPMan and OMII-SP) are providing tools to allow easy configuration of security infrastructures, exploiting previous successful projects using Shibboleth and PERMIS. This paper presents the model in which these tools interoperate to provide secure and simple access to Grid resources for non-technical users
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Durability of double-shell slurry feed grouts: FY-90 results
Plans for disposal of the low-level fraction of selected double-shell tank wastes at Hanford include grouting. Grout disposal is the process of mixing low-level liquid waste with cementitious powders and pumping the slurry to near-surface, underground concrete vaults; hydration results in the formation of a solid product that binds/encapsulates the radioactive/hazardous constituents. In this durability program, previous studies have indicated a strong impact from curing temperature/time on strength and leach resistance of DSSF grouts. The current studies were expanded to determine whether these impacts could be attributed to other factors, such as dry blend composition and waste concentration. Major conclusions: grouts from dry blends with 40 wt% limestone had lower strengths; compressive strengths and leach resistance decreased with increased curing temperature/time; leach resistance increased for grouts prepared with dilute DSSF; nitrate leach resistance increased with high slag/cement ratios, dilute DSSF, and low curing temperatures; amount of drainable liquids for grouts using diluted DSSF was lowest when slag content was high; the 2 most significant factors affecting grout properties were the slag/cement ratio and waste dilution (slag-waste reactions appear to dominate the properties of DSSF grouts)
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Characterization of a low-level radioactive waste grout: Sampling and test results
WHC manages and operates the grout treatment facility at Hanford as part of a DOE program to clean up wastes stored at federal nuclear production sites. PNL provides support to the grout disposal program through pilot-scale tests, performance assessments, and formulation verification activities. in 1988 and 1989, over one million gallons of a low-level radioactive liquid waste was processed through the facility to produce a grout waste that was then deposited in an underground vault. The liquid waste was phosphate/sulfate waste (PSW) generated in decontamination of the N Reactor. PNL sampled and tested the grout produced during the second half of the PSW campaign to support quality verification activities prior to grout vault closure. Samples of grout were obtained by inserting nested-tube samplers into the grout slurry in the vault. After the grout had cured, the inner tube of the sampler was removed and the grout samples extracted. Tests for compressive strength, sonic velocity, and leach testing were used to assess grout quality; results were compared to those from pilot-scale test grouts made with a simulated PSW. The grout produced during the second half of the PSW campaign exceeded compressive strength and leachability formulation criteria. The nested tube samplers were effective in collecting samples of grout although their use introduced greater variability into the compressive strength data
Caspase-mediated cleavage of raptor participates in the inactivation of mTORC1 during cell death.
The mammalian target of rapamycin complex 1 (mTORC1) is a highly conserved protein complex regulating key pathways in cell growth. Hyperactivation of mTORC1 is implicated in numerous cancers, thus making it a potential broad-spectrum chemotherapeutic target. Here, we characterized how mTORC1 responds to cell death induced by various anticancer drugs such rapamycin, etoposide, cisplatin, curcumin, staurosporine and Fas ligand. All treatments induced cleavage in the mTORC1 component, raptor, resulting in decreased raptor-mTOR interaction and subsequent inhibition of the mTORC1-mediated phosphorylation of downstream substrates (S6K and 4E-BP1). The cleavage was primarily mediated by caspase-6 and occurred at two sites. Mutagenesis at one of these sites, conferred resistance to cell death, indicating that raptor cleavage is important in chemotherapeutic apoptosis
Integrating security solutions to support nanoCMOS electronics research
The UK Engineering and Physical Sciences Research Council (EPSRC) funded Meeting the Design Challenges of nanoCMOS Electronics (nanoCMOS) is developing a research infrastructure for collaborative electronics research across multiple institutions in the UK with especially strong industrial and commercial involvement. Unlike other domains, the electronics industry is driven by the necessity of protecting the intellectual property of the data, designs and software associated with next generation electronics devices and therefore requires fine-grained security. Similarly, the project also demands seamless access to large scale high performance compute resources for atomic scale device simulations and the capability to manage the hundreds of thousands of files and the metadata associated with these simulations. Within this context, the project has explored a wide range of authentication and authorization infrastructures facilitating compute resource access and providing fine-grained security over numerous distributed file stores and files. We conclude that no single security solution meets the needs of the project. This paper describes the experiences of applying X.509-based certificates and public key infrastructures, VOMS, PERMIS, Kerberos and the Internet2 Shibboleth technologies for nanoCMOS security. We outline how we are integrating these solutions to provide a complete end-end security framework meeting the demands of the nanoCMOS electronics domain
Supercurrent flow through an effective double barrier structure
Supercurrent flow is studied in a structure that in the Ginzburg-Landau
regime can be described in terms of an effective double barrier potential. In
the limit of strongly reflecting barriers, the passage of Cooper pairs through
such a structure may be viewed as a realization of resonant tunneling with a
rigid wave function. For interbarrier distances smaller than no
current-carrying solutions exist. For distances between and , four
solutions exist. The two symmetric solutions obey a current-phase relation of
, while the two asymmetric solutions satisfy
for all allowed values of the current. As the distance
exceeds , a new group of four solutions appears, each contaning
soliton-type oscillations between the barriers. We prove the inexistence of a
continuous crossover between the physical solutions of the nonlinear
Ginzburg-Landau equation and those of the corresponding linearized
Schr\"odinger equation. We also show that under certain conditions a repulsive
delta function barrier may quantitatively describe a SNS structure. We are thus
able to predict that the critical current of a SNSNS structure vanishes as
, where is lower than the bulk critical temperature.Comment: 20 pages, RevTex, to appear in Phys. Rev. B, 6 figures on request at
[email protected]
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Durability of double-shell tank waste grouts
This report summarizes results of studies conducted in FY89 to assess the durability of grouted DST waste. This is in support of WHC`s grout disposal program to determine the physical/chemical properties of simulated DST grouts cured for extended time periods at elevated temperatures. This report presents results of tests on simulated DST grout samples cured up to 6 months at 75 to 95 C. All the testing and characterization were done on a single formulation of DS slurry feed grout. The simulated waste was the same as in the Nov. 1988 pilot- scale test of grout processing. The dry blend (47 wt% slag, 47 wt% class F fly ash, 6 wt% type I/II portland cement) was mixed with the simulated waste at a mix ratio of 9 lb/gal. Resultant grout slurry was cast into molds and cured at 100% RH at 75, 85, and 95 C. Leach resistance and compressive strength decreased with curing times and temperatures. The samples absorbed water during curing (up to 9 wt%) as a result of osmotic pressures caused by the high salt content within the grout, and this may have caused microcracking and reduced strength. Cracking due to increased internal pressures from salt crystallization also may have occurred as the samples cooled from curing
Taking Fuzzy-Rough Application to Mars: Fuzzy-Rough Feature Selection for Mars Terrain Image Classification
Toeplitz Quantization of K\"ahler Manifolds and
For general compact K\"ahler manifolds it is shown that both Toeplitz
quantization and geometric quantization lead to a well-defined (by operator
norm estimates) classical limit. This generalizes earlier results of the
authors and Klimek and Lesniewski obtained for the torus and higher genus
Riemann surfaces, respectively. We thereby arrive at an approximation of the
Poisson algebra by a sequence of finite-dimensional matrix algebras ,
.Comment: 17 pages, AmsTeX 2.1, Sept. 93 (rev: only typos are corrected
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