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Civitas: Toward a Secure Voting System
Civitas is the first electronic voting system that is coercion-resistant, universally and voter verifiable, and suitable for remote voting. This paper describes the design and implementation of Civitas. Assurance is established in the design through security proofs, and in the implementation through information-flow security analysis. Experimental results give a quantitative evaluation of the tradeoffs between time, cost, and security.Engineering and Applied Science
Using Replication and Partitioning to Build Secure Distributed Systems
A challenging unsolved security problem is how to specify and enforce system-wide security policies; this problem is even more acute in distributed systems with mutual distrust. This paper describes a way to enforce policies for data confidentiality and integrity in such an environment. Programs annotated with security specifications are statically checked and then transformed by the compiler to run securely on a distributed system with untrusted hosts. The code and data of the computation are partitioned across the available hosts in accordance with the security specification. The key contribution is automatic replication of code and data to increase assurance of integrity—without harming confidentiality, and without placing undue trust in any host. The compiler automatically generates secure run-time protocols for communication among the replicated code partitions. Results are given from a prototype implementation applied to various distributed programs
Finding approximate palindromes in strings
We introduce a novel definition of approximate palindromes in strings, and
provide an algorithm to find all maximal approximate palindromes in a string
with up to errors. Our definition is based on the usual edit operations of
approximate pattern matching, and the algorithm we give, for a string of size
on a fixed alphabet, runs in time. We also discuss two
implementation-related improvements to the algorithm, and demonstrate their
efficacy in practice by means of both experiments and an average-case analysis
Connective tissue activation
Human synovial fibroblasts in culture have been stimulated to augment hyaluronate synthesis and glucose utilization by connective tissue activating peptides (CTAP) extracted from human spleen, lymphocytes, platelets, granulocytes, and tumor cells. The platelet-derived mediator CTAP-III also stimulated DNA synthesis in synovial fibroblasts, but CTAP-I from lymphocytes and spleen did not. The present study demonstrates the mitogenic potential of a granulocyte mediator (CTAP-PMN). Normal granuiocytes were prepared with Ficoll-diatrizoate gradients, platelet contamination being estimated by phase microscopy and by radioimmunoassay for the platelet-specific protein, Β thromboglobulin. CTAP-PMN preparations derived from 4 × 10 7 cells/ml stimulated culture 3 H-thymidine incoporation to 3.56 ± 1.32 (SD) times controls levels. Although exposure of praparations to thiols reduced their mitogenicity, CTAP-PMN was relatively heat-stable. SDS gel eletrophoresis of active fractions suggested a molecular weight between 12,700 and 12, 700 daltons. In doulbe immunodiffusion, antisera to CTAP-III showed no reactivity with CTAP-PMN. CTAP-PMN or other granulocyte factors capable of stimulating fibroblast DNA synthesis may play a role in chronic proliferative synovitis or in other settings where exudative inflammation is accompanied by connective tissue growth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37746/1/1780230506_ftp.pd
Deep Convolutional Autoencoders as Generic Feature Extractors in Seismological Applications
The idea of using a deep autoencoder to encode seismic waveform features and
then use them in different seismological applications is appealing. In this
paper, we designed tests to evaluate this idea of using autoencoders as feature
extractors for different seismological applications, such as event
discrimination (i.e., earthquake vs. noise waveforms, earthquake vs. explosion
waveforms, and phase picking). These tests involve training an autoencoder,
either undercomplete or overcomplete, on a large amount of earthquake
waveforms, and then using the trained encoder as a feature extractor with
subsequent application layers (either a fully connected layer, or a
convolutional layer plus a fully connected layer) to make the decision. By
comparing the performance of these newly designed models against the baseline
models trained from scratch, we conclude that the autoencoder feature extractor
approach may only perform well under certain conditions such as when the target
problems require features to be similar to the autoencoder encoded features,
when a relatively small amount of training data is available, and when certain
model structures and training strategies are utilized. The model structure that
works best in all these tests is an overcomplete autoencoder with a
convolutional layer and a fully connected layer to make the estimation
A survey of physician receptivity to molecular diagnostic testing and readiness to act on results for early-stage colon cancer patients.
BACKGROUND: We sought to assess physician interest in molecular prognosic testing for patients with early stage colon cancer, and identify factors associated with the likelihood of test adoption.
METHODS: We identified physicians who care for patients with early-stage (pN0) colon cancer patients, mailed them a survey, and analyzed survey responses to assess clinician receptivity to the use of a new molecular test (GUCY2C) that identifies patients at risk for recurrence, and clinician readiness to act on abnormal test results.
RESULTS: Of 104 eligible potential respondents, 41 completed and returned the survey. Among responding physicians, 56 % were receptive to using the new prognostic test. Multivariable analyses showed that physicians in academic medical centers were significantly more receptive to molecular test use than those in non-academic settings. Forty-one percent of respondents were ready to act on abnormal molecular test results. Physicians who viewed current staging methods as inaccurate and were confident in their capacity to incorporate molecular testing in practice were more likely to say they would act on abnormal test results.
CONCLUSIONS: Physician receptivity to molecular diagnostic testing for early-stage colon cancer patients is likely to be influenced by practice setting and perceptions related to delivering quality care to patients.
TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01972737
Graphene formation on SiC substrates
Graphene layers were created on both C and Si faces of semi-insulating,
on-axis, 4H- and 6H-SiC substrates. The process was performed under high vacuum
(<10-4 mbar) in a commercial chemical vapor deposition SiC reactor. A method
for H2 etching the on-axis sub-strates was developed to produce surface steps
with heights of 0.5 nm on the Si-face and 1.0 to 1.5 nm on the C-face for each
polytype. A process was developed to form graphene on the substrates
immediately after H2 etching and Raman spectroscopy of these samples confirmed
the formation of graphene. The morphology of the graphene is described. For
both faces, the underlying substrate morphology was significantly modified
during graphene formation; sur-face steps were up to 15 nm high and the uniform
step morphology was sometimes lost. Mo-bilities and sheet carrier
concentrations derived from Hall Effect measurements on large area (16 mm
square) and small area (2 and 10 um square) samples are presented and shown to
compare favorably to recent reports.Comment: European Conference on Silicon Carbide and Related Materials 2008
(ECSCRM '08), 4 pages, 4 figure
Accuracy of peak VO2 assessments in career firefighters
Abstract Background Sudden cardiac death is the leading cause of on-duty death in United States firefighters. Accurately assessing cardiopulmonary capacity is critical to preventing, or reducing, cardiovascular events in this population. Methods A total of 83 male firefighters performed Wellness-Fitness Initiative (WFI) maximal exercise treadmill tests and direct peak VO2 assessments to volitional fatigue. Of the 83, 63 completed WFI sub-maximal exercise treadmill tests for comparison to directly measured peak VO2 and historical estimations. Results Maximal heart rates were overestimated by the traditional 220-age equation by about 5 beats per minute (p < .001). Peak VO2 was overestimated by the WFI maximal exercise treadmill and the historical WFI sub-maximal estimation by ~ 1MET and ~ 2 METs, respectively (p < 0.001). The revised 2008 WFI sub-maximal treadmill estimation was found to accurately estimate peak VO2 when compared to directly measured peak VO2. Conclusion Accurate assessment of cardiopulmonary capacity is critical in determining appropriate duty assignments, and identification of potential cardiovascular problems, for firefighters. Estimation of cardiopulmonary fitness improves using the revised 2008 WFI sub-maximal equation
Viscosity Bound and Causality Violation
In recent work we showed that, for a class of conformal field theories (CFT)
with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio,
, could violate the conjectured Kovtun-Starinets-Son viscosity bound,
. In this paper we argue, in the context of the same model,
that tuning below induces microcausality violation
in the CFT, rendering the theory inconsistent. This is a concrete example in
which inconsistency of a theory and a lower bound on viscosity are correlated,
supporting the idea of a possible universal lower bound on for all
consistent theories.Comment: 5 pages, 2 figures; v2: a slight change in the title and minor
revisions made, references update
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