197 research outputs found
Inverting Adversarially Robust Networks for Image Synthesis
Recent research in adversarially robust classifiers suggests their
representations tend to be aligned with human perception, which makes them
attractive for image synthesis and restoration applications. Despite favorable
empirical results on a few downstream tasks, their advantages are limited to
slow and sensitive optimization-based techniques. Moreover, their use on
generative models remains unexplored. This work proposes the use of robust
representations as a perceptual primitive for feature inversion models, and
show its benefits with respect to standard non-robust image features. We
empirically show that adopting robust representations as an image prior
significantly improves the reconstruction accuracy of CNN-based feature
inversion models. Furthermore, it allows reconstructing images at multiple
scales out-of-the-box. Following these findings, we propose an
encoding-decoding network based on robust representations and show its
advantages for applications such as anomaly detection, style transfer and image
denoising
Controlling suction by vapour equilibrium technique at different temperatures, application to the determination of the water retention properties of MX80 clay
Problems related to unsaturated soils are frequently encountered in
geotechnical or environmental engineering works. In most cases, for the purpose
of simplicity, the problems are studied by considering the suction effects on
volume change or shear strength under isothermal conditions. Under isothermal
condition, very often, a temperature independent water retention curve is
considered in the analysis, which is obviously a simplification. When the
temperature changes are too significant to be neglected, it is necessary to
account for the thermal effects. In this paper, a method for controlling
suction using the vapour equilibrium technique at different temperatures is
presented. First, calibration of various saturated saline solutions was carried
out from temperature of 20 degrees C to 60 degrees C. A mirror psychrometer was
used for the measurement of relative humidity generated by saturated saline
solutions at different temperatures. The results obtained are in good agreement
with the data from the literature. This information was then used to determine
the water retention properties of MX80 clay, which showed that the retention
curve is shifting down with increasing of temperature
Potential benefits from the adoption of new groundnut varieties in northern Vietnam: An ex ante assessment
Enabled by land reforms and fuelled by technological change, agricultural production in Vietnam grew tremendously after the mid-1980s. Focusing on groundnut, an export-oriented cash and food crop, this paper provides estimates of potential benefits from the adoption of improved varieties in northern Vietnam. At farm level, switching over to improved varieties generates additional revenue of VND1.8 to 3.9 million per hectare (US35.8 million) at a real discount rate of 5%. These benefits will be 14% larger if the groundnut area continues to expand at the rate achieved in the recent past
Security-reliability analysis in CR-NOMA IoT network under I/Q imbalance
This paper presents a controllable analysis framework for evaluating the reliability and security
of underlay cognitive radio networks (CRs) relying on non-orthogonal multiple access (NOMA). In such
systems, a secondary base station (BS) transmits confidential information to multiple secondary users
uniformly distributed in the presence of a nearby located external eavesdropper. Moreover, transmit power
constraints are introduced to limit the interference to the primary imposed by cognitive base stations. As an
effective approach of multiple input single output (MISO) systems, the transmit antenna selection (TAS)
is selected in the BS to improve the secrecy performance of the primary networks. Furthermore, we first
consider the impact of quadrature-phase imbalance (IQI) to characterize the secure performance of the
considered network in practice. Then, the degraded performance is evaluated in terms of outage probability
(OP), intercept probability (IP), and effective secrecy throughput (EST) of two NOMA users. The optimal
EST can be achieved through simulations while the results of OP and IP provide guidelines in the design of
IQI-aware CR-NOMA systems. Finally, the trade-off between OP and IP with transmit signal-to-noise ratio
(SNR) at the BS is investigated for reflecting the security characteristic. Finally, the trade-off between OP
and IP with transmit signal-to-noise ratio (SNR) at the BS is studied for displaying the security characteristic.
Numerical results show that increasing the number of transmit antennas at the BS and other main parameters
improves performance. Moreover, when the system parameters are reasonably set, the secondary NOMA
user in CR-NOMA can be reached secure requirements regardless of the controlled IQI.Web of Science1111905611904
Mapping for engagement: setting up a community based participatory research project to reach underserved communities at risk for Hepatitis C in Ho Chi Minh City, Vietnam
Background: Approximately 1. 07 million people in Vietnam are infected with hepatitis C virus (HCV). To address this epidemic, the South East Asian Research Collaborative in Hepatitis (SEARCH) launched a 600-patient cohort study and two clinical trials, both investigating shortened treatment strategies for chronic HCV infection with direct-acting antiviral drugs. We conducted ethnographic research with a subset of trial participants and found that the majority were aware of HCV infection and its implications and were motivated to seek treatment. However, people who inject drugs (PWID), and other groups at risk for HCV were under-represented, although injecting drug use is associated with high rates of HCV. Material and Methods: We designed a community-based participatory research (CBPR) study to engage in dialogues surrounding HCV and other community-prioritized health issues with underserved groups at risk for HCV in Ho Chi Minh City. The project consists of three phases: situation analysis, CBPR implementation, and dissemination. In this paper, we describe the results of the first phase (i.e., the situation analysis) in which we conducted desk research and organized stakeholder mapping meetings with representatives from local non-government and community-based organizations where we used participatory research methods to identify and analyze key stakeholders working with underserved populations. Results: Twenty six institutions or groups working with the key underserved populations were identified. Insights about the challenges and dynamics of underserved communities were also gathered. Two working groups made up of representatives from the NGO and CBO level were formed. Discussion: Using the information provided by local key stakeholders to shape the project has helped us to build solid relationships, give the groups a sense of ownership from the early stages, and made the project more context specific. These steps are not only important preliminary steps for participatory studies but also for other research that takes place within the communities
Security–reliability analysis of AF full-duplex relay networks using self-energy recycling and deep neural networks
This paper investigates the security-reliability of simultaneous wireless information and
power transfer (SWIPT)-assisted amplify-and-forward (AF) full-duplex (FD) relay networks. In
practice, an AF-FD relay harvests energy from the source (S) using the power-splitting (PS) protocol.
We propose an analysis of the related reliability and security by deriving closed-form formulas for
outage probability (OP) and intercept probability (IP). The next contribution of this research is an
asymptotic analysis of OP and IP, which was generated to obtain more insight into important system
parameters. We validate the analytical formulas and analyze the impact on the key system parameters
using Monte Carlo simulations. Finally, we propose a deep learning network (DNN) with minimal
computation complexity and great accuracy for OP and IP predictions. The effects of the system’s
primary parameters on OP and IP are examined and described, along with the numerical data.Web of Science2317art. no. 761
Pichia pastoris versus Saccharomyces cerevisiae:a case study on the recombinant production of human granulocyte-macrophage colony-stimulating factor
BACKGROUND: Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is a glycoprotein that has been approved by the FDA for the treatment of neutropenia and leukemia in combination with chemotherapies. Recombinant hGM-CSF is produced industrially using the baker's yeast, Saccharomyces cerevisiae, by large-scale fermentation. The methylotrophic yeast, Pichia pastoris, has emerged as an alternative host cell system due to its shorter and less immunogenic glycosylation pattern together with higher cell density growth and higher secreted protein yield than S. cerevisiae. In this study, we compared the pipeline from gene to recombinant protein in these two yeasts. RESULTS: Codon optimization in silico for both yeast species showed no difference in frequent codon usage. However, rhGM-CSF expressed from S. cerevisiae BY4742 showed a significant discrepancy in molecular weight from those of P. pastoris X33. Analysis showed purified rhGM-CSF species with molecular weights ranging from 30 to more than 60 kDa. Fed-batch fermentation over 72 h showed that rhGM-CSF was more highly secreted from P. pastoris than S. cerevisiae (285 and 64 mg total secreted protein/L, respectively). Ion exchange chromatography gave higher purity and recovery than hydrophobic interaction chromatography. Purified rhGM-CSF from P. pastoris was 327 times more potent than rhGM-CSF from S. cerevisiae in terms of proliferative stimulating capacity on the hGM-CSF-dependent cell line, TF-1. CONCLUSION: Our data support a view that the methylotrophic yeast P. pastoris is an effective recombinant host for heterologous rhGM-CSF production
Using multiple lines of evidence to assess the risk of ecosystem collapse
Effective ecosystem risk assessment relies on a conceptual understanding of ecosystem dynamics and the synthesis of multiple lines of evidence. Risk assessment protocols and ecosystem models integrate limited observational data with threat scenarios, making them valuable tools for monitoring ecosystem status and diagnosing key mechanisms of decline to be addressed by management. We applied the IUCN Red List of Ecosystems criteria to quantify the risk of collapse of the Meso-American Reef, a unique ecosystem containing the second longest barrier reef in the world. We collated a wide array of empirical data (field and remotely sensed), and used a stochastic ecosystem model to backcast past ecosystem dynamics, as well as forecast future ecosystem dynamics under 11 scenarios of threat. The ecosystem is at high risk from mass bleaching in the coming decades, with compounding effects of ocean acidification, hurricanes, pollution and fishing. The overall status of the ecosystem is Critically Endangered (plausibly Vulnerable to Critically Endangered), with notable differences among Red List criteria and data types in detecting the most severe symptoms of risk. Our case study provides a template for assessing risks to coral reefs and for further application of ecosystem models in risk assessment
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