7,987 research outputs found
On a problem in eigenvalue perturbation theory
We consider additive perturbations of the type , ,
where and are self-adjoint operators in a separable Hilbert space
and is bounded. In addition, we assume that the range of
is a generating (i.e., cyclic) subspace for . If is an
eigenvalue of , then under the additional assumption that is
nonnegative, the Lebesgue measure of the set of all for which
is an eigenvalue of is known to be zero. We recall this
result with its proof and show by explicit counterexample that the
nonnegativity assumption cannot be removed.Comment: 10 pages; added Lemma 2.4, typos removed; to appear in J. Math. Anal.
App
Bounds for Invariance Pressure
This paper provides an upper for the invariance pressure of control sets with
nonempty interior and a lower bound for sets with finite volume. In the special
case of the control set of a hyperbolic linear control system in R^{d} this
yields an explicit formula. Further applications to linear control systems on
Lie groups and to inner control sets are discussed.Comment: 16 page
Electrochemistry reveals archaeological materials
The characterization of materials constituting cultural artefacts is a challenging step in their conservation, due to the objectâs uniqueness and the reduced number of conservation institutes able to supply non-destructive analysis. We propose an alternative analytical tool, which combines accessibility (low cost and portable) and high sensitivity, based on electrochemical linear sweep voltammetry (LSV) with paraffin impregnated graphite electrode (PIGE). To investigate the composition of âwhite alloysâ that certainly have been used as decoration on copper-based Roman fibulae, sampling was done very locally by gently rubbing the selected areas with the PIGE. LSV results evidence the presence of silver, lead, and tin, supporting the argument provided by typological analysis that these metals were used for decoration
Exports, Services and Value Added - A National, International and Regional Analysis for Austria
Austrian business cycles are strongly dependent on the development of foreign exports. The paper deals with two important issues in this context: What is the impact of foreign exports on total growth in the Austrian economy? A more and more globalized economy implies that the share of foreign imports in the production of export commodities increases. This suggests that the contribution of foreign exports to domestic growth will diminish over time ? this hypothesis will be tested in the paper. In addition, the results for Austria will be compared with those for other countries in the EU as well as the OECD. Export activities are not evenly distributed over space: While some regions are more specialized in the production of commodities for the domestic market, other regions are much more dependent on foreign exports. In the paper, the regional economic consequences of the value-added impacts of foreign exports will be analysed. The paper will make use of national input-output tables for the years 1995, 2000 and 2003 as well as input-output tables for OECD countries to examine the national economic impacts of foreign exports and an international comparison. Furthermore, a multiregional model for Austria ("MultiREG") will be applied for estimating the corresponding regional impacts.Competitiveness, Export of Services
S-FaaS: Trustworthy and Accountable Function-as-a-Service using Intel SGX
Function-as-a-Service (FaaS) is a recent and already very popular paradigm in
cloud computing. The function provider need only specify the function to be
run, usually in a high-level language like JavaScript, and the service provider
orchestrates all the necessary infrastructure and software stacks. The function
provider is only billed for the actual computational resources used by the
function invocation. Compared to previous cloud paradigms, FaaS requires
significantly more fine-grained resource measurement mechanisms, e.g. to
measure compute time and memory usage of a single function invocation with
sub-second accuracy. Thanks to the short duration and stateless nature of
functions, and the availability of multiple open-source frameworks, FaaS
enables non-traditional service providers e.g. individuals or data centers with
spare capacity. However, this exacerbates the challenge of ensuring that
resource consumption is measured accurately and reported reliably. It also
raises the issues of ensuring computation is done correctly and minimizing the
amount of information leaked to service providers.
To address these challenges, we introduce S-FaaS, the first architecture and
implementation of FaaS to provide strong security and accountability guarantees
backed by Intel SGX. To match the dynamic event-driven nature of FaaS, our
design introduces a new key distribution enclave and a novel transitive
attestation protocol. A core contribution of S-FaaS is our set of resource
measurement mechanisms that securely measure compute time inside an enclave,
and actual memory allocations. We have integrated S-FaaS into the popular
OpenWhisk FaaS framework. We evaluate the security of our architecture, the
accuracy of our resource measurement mechanisms, and the performance of our
implementation, showing that our resource measurement mechanisms add less than
6.3% latency on standardized benchmarks
The Impact of Technology on Individuals with Down Syndrome and Their Families
The purpose of this study was to determine the role technology plays in the everyday lives of individuals with Down syndrome and their families. Data was collected via an online questionnaire for parents of adolescents with Down syndrome and took place in two phases: the pilot phase and the large-scale data collection phase. The pilot phase consisted of constructing, giving, and modifying the questionnaire. The large-scale data collection phase included disseminating the questionnaire through social media and resulted in 107 responses. These revealed that technology is widely used by individuals with Down syndrome. As a main outcome, technology provided these individuals with opportunities to act independently and allowed their family units to make necessary adaptations to achieve higher levels of functioning
Psychological Perspectives on the Lives of Transgender Individuals: A Review of the Literature
Transgender people as a whole suffer from social invisibility, as the general public is often misinformed about them. Because of the misinformation and ignorance surrounding public opinion of transgender people, it is difficult to conduct psychological studies involving this population. The purpose for this review is to shed some light on how the lives of transgender peoples actually are. The main areas that will be addressed in this review include tracking how transgenderism has been viewed from a clinical psychology perspective in the current and past editions of the Diagnostic and Statistical Manual, how transgender people face transphobia and are victims of hate crimes, how they are affected by familial social support or lack thereof, and internalized feelings of distress experienced by transgender individuals.B.A. (Bachelor of Arts
Fuzzy logic control for camera tracking system
A concept utilizing fuzzy theory has been developed for a camera tracking system to provide support for proximity operations and traffic management around the Space Station Freedom. Fuzzy sets and fuzzy logic based reasoning are used in a control system which utilizes images from a camera and generates required pan and tilt commands to track and maintain a moving target in the camera's field of view. This control system can be implemented on a fuzzy chip to provide an intelligent sensor for autonomous operations. Capabilities of the control system can be expanded to include approach, handover to other sensors, caution and warning messages
- âŠ