23 research outputs found
AudioFool: Fast, Universal and synchronization-free Cross-Domain Attack on Speech Recognition
Automatic Speech Recognition systems have been shown to be vulnerable to
adversarial attacks that manipulate the command executed on the device. Recent
research has focused on exploring methods to create such attacks, however, some
issues relating to Over-The-Air (OTA) attacks have not been properly addressed.
In our work, we examine the needed properties of robust attacks compatible with
the OTA model, and we design a method of generating attacks with arbitrary such
desired properties, namely the invariance to synchronization, and the
robustness to filtering: this allows a Denial-of-Service (DoS) attack against
ASR systems. We achieve these characteristics by constructing attacks in a
modified frequency domain through an inverse Fourier transform. We evaluate our
method on standard keyword classification tasks and analyze it in OTA, and we
analyze the properties of the cross-domain attacks to explain the efficiency of
the approach.Comment: 10 pages, 11 Figure
Bitcoin and portfolio diversification : a portfolio optimization approach
This study investigates the performance of Bitcoin as a diversifier under different constraining portfolio optimization frameworks. The study employs different constraining optimization frameworks that seek to maximize risk-adjusted returns (Sharpe ratio) of the portfolio by optimizing allocations to each asset class (asset allocation). The performance attributes are evaluated by comparing the portfolios both with and without Bitcoin under frameworks ranging from equal-weighted, risk-parity, and semi-constrained to unconstrained. This study suggests that Bitcoin, due to its exotic nature, unwavering appeal, and unknown set of drivers, could act as a diversifier in normal market conditions, and it might also have some borderline hedge to safe haven properties. The results further suggest that while Bitcoin may be a potential diversifier for a risk-seeking investor, the risk-averse investor must exercise caution by limiting their exposure to Bitcoin in their portfolios, as unnecessary exposure may increase the probability of losses in extreme market conditions
Optical Power Control to Efficiently Handle Flex-Grid Spectrum Gain over Existing Fixed-Grid Network Infrastructures
International audienceThe exponential traffic growth in optical networks has triggered the evolution from Fixed-Grid to Flex-Grid technology. This evolution allows better spectral efficiency and spectrum usage over current networks in order to facilitate dynamic and huge traffic demands. The integration of Flex-Grid technology increases the number of optical channels established over optical links, leading, however, to an increase in amplification power and possibly saturating optical amplifiers. In this work, we propose a power adaptation process that takes advantage of link optical signal to noise ratio (OSNR) margins to allow network operators to support this power increase while maintaining the use of legacy amplifiers. Results show that controlling channel optical power benefits from the Flex-Grid in terms of spectrum and capacity gain using in-place amplifier infrastructure
On the Legacy Amplifier Limitation in Flexgrid Optical Networks
International audienceFlexgrid technology is an interesting solution to improve network capacity. However, for a given spectral band, it gives rise to the increase of the number of channels, requiring more amplification power in respect with the conventional fixed grid technology. In this work, we demonstrate that re-engineering the link margins allows supporting this increase while keeping in use legacy amplifier
Knowledge, Perception, Attitudes and Behavior on Influenza Immunization and the Determinants of Vaccination
BACKGROUND: We sought to determine the knowledge of, perception, attitudes, and behaviors toward influenza virus and immunization, and the determinants of vaccination among students, patients, and Healthcare Workers (HCWs) at the American University of Beirut and its affiliated Medical Center. METHODS: We conducted a cross-sectional study between October 2016 and January 2017 utilizing a self-administered questionnaire that was provided to 247 randomly selected adult participants. Data collected included socio-demographic characteristics, prior vaccination against influenza, knowledge, perception, attitudes, and behaviors toward influenza and influenza immunization. A multivariable regression model was used to evaluate for independent associations between the different variables and regular or yearly vaccination as a primary outcome. RESULTS: The overall survey response rate was 77%. A substantial proportion of respondents (47.4%) had never received the influenza vaccine. Only 10.2% of students, 19.1% of patients, and 35.6% of HCWs reported regular or yearly influenza vaccine uptake. HCWs had the lowest knowledge score about influenza and its vaccine despite high self-reported levels of knowledge. Barriers to vaccinations included lack of information (31%), fear of adverse effects (29%), and a perception of not being at risk (23%). Several factors were independently associated with regular or yearly vaccination uptake including having children (adjusted OR = 3.8; 95% CI 1.2-12.5), a "very good" self-reported level of knowledge (OR = 16.3; 95% CI 1.4-194.2) and being afraid of the consequences of influenza (OR = 0.2; 95% CI 0.1-0.6). CONCLUSION: Adherence rates with regular or yearly vaccination against influenza remain low across all study groups. We were able to identify predictors as well as barriers to vaccination. Future awareness and vaccination campaigns should specifically aim at correcting misconceptions about vaccination, particularly among HCWs, along with addressing the barriers to vaccination. Predictors of vaccination should be integrated in the design of future campaigns
Link Design and Legacy Amplifier Limitation in Flex-grid Optical Networks
International audienceFlex-grid technology is an effective mean to improve the spectral efficiency of optical communications. For a given amplifier spectral bandwidth, it gives rise to the increase of the number of optical channels as it reduces the channel spacing. Therefore, in order to reap full benefits from flex-grid saved spectrum, further amplification power is required with respect to conventional fixed grid. This is a strong limitation if the legacy amplifiers cannot meet this new requirement due to their optical power limits. In this work, we demonstrate that exploiting the link margins allows supporting this increase while maintaining in use legacy amplifiers
Mild and efficient protection of diol and carbonyls as cyclic acetals catalysed by iron (III) chloride
BIOVERT:INGENIERIE+MAL:LC
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Moraxella nonliquefaciens septic arthritis in a hematopoietic stem cell transplant patient a case report and review of the literature
Background: Septic arthritis is a common rheumatologic condition with myriad microbiological causative agents. Moraxella is one of the very rare causes of septic arthritis. We hereby present the third case of Moraxella nonliquefaciens septic arthritis and the first case in a hematopoietic stem cell transplant patient (HSCT) along with a brief review of the literature. Methods: We used PubMed with google search engine to search the literature for reported cases of moraxella septic arthritis. Results: Information on 19 other cases of moraxella infectious arthritis was found. M. catarrhalis was the most common species isolated. Only 2 reports on M. nonliquefaciens were found; the first one in a multiple myeloma patient and the second one in a diabetic patient on hemodialysis. Predisposing conditions included inflammatory arthritis, prosthetic joints, diabetes, Human Immunodeficiency Virus (HIV) infection, Hepatitis C, hemodialysis, esophageal cancer, valve replacements, alcoholism and Intravenous (IV) drug use. The age group of the reported cases ranged from 3 months to 78 years. Conclusion: Infectious arthritis with Moraxella spp. is a very rare entity which can occur in any age group and in the setting of various underlying medical conditions. Keywords: Moraxella nonliquefaciens, Septic arthritis, Hematopoietic stem cell transplan