598 research outputs found
Sensitivity of the Eisenberg-Noe clearing vector to individual interbank liabilities
We quantify the sensitivity of the Eisenberg-Noe clearing vector to
estimation errors in the bilateral liabilities of a financial system in a
stylized setting. The interbank liabilities matrix is a crucial input to the
computation of the clearing vector. However, in practice central bankers and
regulators must often estimate this matrix because complete information on
bilateral liabilities is rarely available. As a result, the clearing vector may
suffer from estimation errors in the liabilities matrix. We quantify the
clearing vector's sensitivity to such estimation errors and show that its
directional derivatives are, like the clearing vector itself, solutions of
fixed point equations. We describe estimation errors utilizing a basis for the
space of matrices representing permissible perturbations and derive analytical
solutions to the maximal deviations of the Eisenberg-Noe clearing vector. This
allows us to compute upper bounds for the worst case perturbations of the
clearing vector in our simple setting. Moreover, we quantify the probability of
observing clearing vector deviations of a certain magnitude, for uniformly or
normally distributed errors in the relative liability matrix.
Applying our methodology to a dataset of European banks, we find that
perturbations to the relative liabilities can result in economically sizeable
differences that could lead to an underestimation of the risk of contagion. Our
results are a first step towards allowing regulators to quantify errors in
their simulations.Comment: 37 page
Spin-resolved electron waiting times in a quantum dot spin valve
We study the electronic waiting time distributions (WTDs) in a
non-interacting quantum dot spin valve by varying spin polarization and the
noncollinear angle between the magnetizations of the leads using scattering
matrix approach. Since the quantum dot spin valve involves two channels (spin
up and down) in both the incoming and outgoing channels, we study three
different kinds of WTDs, which are two-channel WTD, spin-resolved
single-channel WTD and cross-channel WTD. We analyze the behaviors of WTDs in
short times, correlated with the current behaviors for different spin
polarizations and noncollinear angles. Cross-channel WTD reflects the
correlation between two spin channels and can be used to characterize the spin
transfer torque process. We study the influence of the earlier detection on the
subsequent detection from the perspective of cross-channel WTD, and define the
influence degree quantity as the cumulative absolute difference between
cross-channel WTDs and first passage time distributions to quantitatively
characterize the spin flip process. The influence degree shows a similar
behavior with spin transfer torque and can be a new pathway to characterize
spin correlation in spintronics system.Comment: 9 pages, 7 figure
SARS-related Perceptions in Hong Kong
To understand different aspects of community responses related to severe acute respiratory syndrome (SARS), 2 population-based, random telephone surveys were conducted in June 2003 and January 2004 in Hong Kong. More than 70% of respondents would avoid visiting hospitals or mainland China to avoid contracting SARS. Most respondents believed that SARS could be transmitted through droplets, fomites, sewage, and animals. More than 90% believed that public health measures were efficacious means of prevention; 40.4% believed that SARS would resurge in Hong Kong; and ≈70% would then wear masks in public places. High percentages of respondents felt helpless, horrified, and apprehensive because of SARS. Approximately 16% showed signs of posttraumatic symptoms, and ≈40% perceived increased stress in family or work settings. The general public in Hong Kong has been very vigilant about SARS but needs to be more psychologically prepared to face a resurgence of the epidemic
Multimodal Machine Learning for Automated ICD Coding
This study presents a multimodal machine learning model to predict ICD-10
diagnostic codes. We developed separate machine learning models that can handle
data from different modalities, including unstructured text, semi-structured
text and structured tabular data. We further employed an ensemble method to
integrate all modality-specific models to generate ICD-10 codes. Key evidence
was also extracted to make our prediction more convincing and explainable. We
used the Medical Information Mart for Intensive Care III (MIMIC -III) dataset
to validate our approach. For ICD code prediction, our best-performing model
(micro-F1 = 0.7633, micro-AUC = 0.9541) significantly outperforms other
baseline models including TF-IDF (micro-F1 = 0.6721, micro-AUC = 0.7879) and
Text-CNN model (micro-F1 = 0.6569, micro-AUC = 0.9235). For interpretability,
our approach achieves a Jaccard Similarity Coefficient (JSC) of 0.1806 on text
data and 0.3105 on tabular data, where well-trained physicians achieve 0.2780
and 0.5002 respectively.Comment: Machine Learning for Healthcare 201
Perceptions on site-specific advanced practice roles for radiation therapists in Singapore : a single centre study
Perception of the radiation oncologists (ROs) and radiation therapists (RTTs) on site-specific advanced practice (SSAP) roles for RTTs, the establishment of SSAP in radiotherapy and the possible implication on current services in Singapore were assessed. Opinions of ROs and RTTs on management support, driving forces, restraints and implication upon successful establishment of SSAP were obtained. Main findings include strong RO’s support for SSAP development and RTTs' requisition for fair opportunities on role development. Other potential benefits include RTTs' career advancement, job satisfaction and retention. Enhancement of inter-professional relationship, service quality and patient satisfaction is anticipated with greater communication and collaboration
Comparison of Survival Patterns of Northern and Southern Genotypes of the North American Tick \u3cem\u3eIxodes scapularis\u3c/em\u3e (Acari: Ixodidae) under Northern and Southern Conditions
Background: Several investigators have reported genetic differences between northern and southern populations of Ixodes scapularis in North America, as well as differences in patterns of disease transmission. Ecological and behavioral correlates of these genetic differences, which might have implications for disease transmission, have not been reported. We compared survival of northern with that of southern genotypes under both northern and southern environmental conditions in laboratory trials.
Methods: Subadult I. scapularis from laboratory colonies that originated from adults collected from deer from several sites in the northeastern, north central, and southern U.S. were exposed to controlled conditions in environmental chambers. Northern and southern genotypes were exposed to light:dark and temperature conditions of northern and southern sites with controlled relative humidities, and mortality through time was recorded.
Results: Ticks from different geographical locations differed in survival patterns, with larvae from Wisconsin surviving longer than larvae from Massachusetts, South Carolina or Georgia, when held under the same conditions. In another experiment, larvae from Florida survived longer than larvae from Michigan. Therefore, survival patterns of regional genotypes did not follow a simple north–south gradient. The most consistent result was that larvae from all locations generally survived longer under northern conditions than under southern conditions.
Conclusions: Our results suggest that conditions in southern North America are less hospitable than in the north to populations of I. scapularis. Southern conditions might have resulted in ecological or behavioral adaptations that contribute to the relative rarity of I. scapularis borne diseases, such as Lyme borreliosis, in the southern compared to the northern United States
Privacy Risks of Securing Machine Learning Models against Adversarial Examples
The arms race between attacks and defenses for machine learning models has
come to a forefront in recent years, in both the security community and the
privacy community. However, one big limitation of previous research is that the
security domain and the privacy domain have typically been considered
separately. It is thus unclear whether the defense methods in one domain will
have any unexpected impact on the other domain.
In this paper, we take a step towards resolving this limitation by combining
the two domains. In particular, we measure the success of membership inference
attacks against six state-of-the-art defense methods that mitigate the risk of
adversarial examples (i.e., evasion attacks). Membership inference attacks
determine whether or not an individual data record has been part of a model's
training set. The accuracy of such attacks reflects the information leakage of
training algorithms about individual members of the training set. Adversarial
defense methods against adversarial examples influence the model's decision
boundaries such that model predictions remain unchanged for a small area around
each input. However, this objective is optimized on training data. Thus,
individual data records in the training set have a significant influence on
robust models. This makes the models more vulnerable to inference attacks.
To perform the membership inference attacks, we leverage the existing
inference methods that exploit model predictions. We also propose two new
inference methods that exploit structural properties of robust models on
adversarially perturbed data. Our experimental evaluation demonstrates that
compared with the natural training (undefended) approach, adversarial defense
methods can indeed increase the target model's risk against membership
inference attacks.Comment: ACM CCS 2019, code is available at
https://github.com/inspire-group/privacy-vs-robustnes
Key Articles, Guidelines, and Consensus Papers Relative to the Treatment of Dyslipidemias—2005
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90074/1/phco.26.7.939.pd
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