7,344 research outputs found
Beyond Good and Evil: Formalizing the Security Guarantees of Compartmentalizing Compilation
Compartmentalization is good security-engineering practice. By breaking a
large software system into mutually distrustful components that run with
minimal privileges, restricting their interactions to conform to well-defined
interfaces, we can limit the damage caused by low-level attacks such as
control-flow hijacking. When used to defend against such attacks,
compartmentalization is often implemented cooperatively by a compiler and a
low-level compartmentalization mechanism. However, the formal guarantees
provided by such compartmentalizing compilation have seen surprisingly little
investigation.
We propose a new security property, secure compartmentalizing compilation
(SCC), that formally characterizes the guarantees provided by
compartmentalizing compilation and clarifies its attacker model. We reconstruct
our property by starting from the well-established notion of fully abstract
compilation, then identifying and lifting three important limitations that make
standard full abstraction unsuitable for compartmentalization. The connection
to full abstraction allows us to prove SCC by adapting established proof
techniques; we illustrate this with a compiler from a simple unsafe imperative
language with procedures to a compartmentalized abstract machine.Comment: Nit
Use of Mobile Technology and Smartphone Apps on the Camino de Santiago: A Comparison of American and European Pilgrims
Mobile technology and smartphone apps are increasingly being used by pilgrims on the Camino de Santiago, leading us to wonder what the role of technology is among Camino pilgrims and what impact technology has on the Camino experience. The purpose of this research is to explore these questions. To do so we conducted separate surveys of American and European pilgrims on the Camino de Santiago. This paper presents our analysis of the results of these surveys, focusing on differences between American and European pilgrims. The results showed that some mobile technologies are used extensively by pilgrims, although pilgrims did not consider the technology to be essential. They also showed that technology impacts the Camino experience in both positive and negative ways. Similarities and differences between American and European pilgrims were found in the results
A novel technique for the direct determination of carrier diffusion lengths in GaAs/AlGaAs heterostructures using cathodoluminescence
A new technique for determining carrier diffusion lengths
in direct gap semiconductors by cathodoluminescence measurement
is presented. Ambipolar diffusion lengths are
determined for GaAs quantum well material, bulk GaAs,
and Al_xGa_(1-x)As with x up to 0.38. A large increase in
the diffusion length is found as x approaches 0.38 and is
attributed to an order of magnitude increase in lifetime
Balancing proliferation and connectivity in PTEN -associated Autism Spectrum Disorder
Germline mutations in PTEN, which encodes a widely expressed phosphatase, was mapped to 10q23 and identified as the susceptibility gene for Cowden syndrome, characterized by macrocephaly and high risks of breast, thyroid, and other cancers. The phenotypic spectrum of PTEN mutations expanded to include autism with macrocephaly only 10 years ago. Neurological studies of patients with PTEN-associated autism spectrum disorder (ASD) show increases in cortical white matter and a distinctive cognitive profile, including delayed language development with poor working memory and processing speed. Once a germline PTEN mutation is found, and a diagnosis of phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome made, the clinical outlook broadens to include higher lifetime risks for multiple cancers, beginning in childhood with thyroid cancer. First described as a tumor suppressor, PTEN is a major negative regulator of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (mTOR) signaling pathway—controlling growth, protein synthesis, and proliferation. This canonical function combines with less well-understood mechanisms to influence synaptic plasticity and neuronal cytoarchitecture. Several excellent mouse models of Pten loss or dysfunction link these neural functions to autism-like behavioral abnormalities, such as altered sociability, repetitive behaviors, and phenotypes like anxiety that are often associated with ASD in humans. These models also show the promise of mTOR inhibitors as therapeutic agents capable of reversing phenotypes ranging from overgrowth to low social behavior. Based on these findings, therapeutic options for patients with PTEN hamartoma tumor syndrome and ASD are coming into view, even as new discoveries in PTEN biology add complexity to our understanding of this master regulator
Direct determination of the ambipolar diffusion length in GaAs/AlGaAs heterostructures by cathodoluminescence
A new technique for determining carrier diffusion lengths by cathodoluminescence measurements is presented. The technique is extremely accurate and can be applied to a variety of structures. Ambipolar diffusion lengths are determined for GaAs quantum well material, bulk GaAs, Al0.21Ga0.79As, and Al0.37Ga0.63As. A large increase in the diffusion length is found for Al0.37Ga0.63As and is attributed to an order of magnitude increase in lifetime
Experiential knowledge as decision-making factor in international construction business
Abstract Operating on the foreign market poses a significant effort for construction firm that cannot be over sighted. During the preparation period, standard data collected prove to be insufficient leaving experiential reasoning to be a main factor for making a decision. Authors examine to question experiential knowledge according to institutional theory guidelines. Institutional theory is used as theoretical base which authors recognize as most comprehensive characterization of market context to date. On basis of a survey results authors bring conclusion that help uncover the nature of the experiential knowledge as a phenomeno
Unconventional Hall effect in oriented CaCoO thin films
Transport properties of the good thermoelectric misfit oxide
CaCoO are examined. In-plane resistivity and Hall resistance
measurements were made on epitaxial thin films which were grown on {\it c}-cut
sapphire substrates using the pulsed laser deposition technique. Interpretation
of the in-plane transport experiments relates the substrate-induced strain in
the resulting film to single crystals under very high pressure ( 5.5 GPa)
consistent with a key role of strong electronic correlation. They are confirmed
by the measured high temperature maxima in both resistivity and Hall
resistance. While hole-like charge carriers are inferred from the Hall effect
measurements over the whole investigated temperature range, the Hall resistance
reveals a non monotonic behavior at low temperatures that could be interpreted
with an anomalous contribution. The resulting unconventional temperature
dependence of the Hall resistance seems thus to combine high temperature
strongly correlated features above 340 K and anomalous Hall effect at low
temperature, below 100 K.Comment: Submitted to Physical Review B (2005
A Tutorial on Prototyping Internet of Things Devices and Systems: A Gentle Introduction to Technology that Shapes Our Lives
The Internet of Things, which has been quietly building and evolving over the past decade, now impacts many aspects of society, including homes, battlefields, and medical communities. Research in information systems, traditionally, has been concentrated on exploring the impacts of such technology, rather than how to actually create systems using it. Although research in design science could especially contribute to the Internet of Things, this type of research from the Information Systems community has been sparse. The most likely cause is the knowledge barriers to learning and understanding this kind of technology development. Recognizing the importance of the continued evolution of the Internet of Things, this paper provides a basic tutorial on how to construct Internet of Things prototypes. The paper is intended to educate Information Systems scholars on how to build their own Internet of Things so they can conduct technical research in this area and instruct their students on how to do the same
Lion metaphors in Chinese and English
This study intends to explore the cultural similarities and differences between the lion metaphors in Mandarin Chinese and British English. Most previous studies on animal metaphors focussed on the expressions with human beings as the target domain by collecting data either from questionnaires or dictionaries based on the Conceptual Metaphor Theory. This study, however, focusses on the expressions with non-humans as the target domains and is based on data collected from authoritative corpora. Three hundred and ninety-seven metaphorical expressions in Mandarin Chinese were identified from the Modern Chinese Corpus compiled by the Centre for Chinese Linguistics of Peking University (CCL Corpus) and 241 metaphorical expressions in British English were identified from the British National Corpus (BNC). After analysing the expressions from the perspective of the source domain and the target domain, the results show that first, the metaphorical expressions in Mandarin Chinese are mainly projected from the lion’s appearance to non-humans, but those in British English are mainly projected from the lion’s characteristics to non-humans. Second, the expressions are mainly mapped onto seven target domains in each language; four are the same. In addition, the dominant evaluation of the seven target domains in each language is mostly neutral. Third, ten conceptual metaphors were generalised from Mandarin Chinese and one from British English. All of these indicate the occurrence of cultural similarities as well as differences in the lion metaphors in the two languages
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