85 research outputs found
A survey of IoT security based on a layered architecture of sensing and data analysis
The Internet of Things (IoT) is leading today’s digital transformation. Relying on a combination of technologies, protocols, and devices such as wireless sensors and newly developed wearable and implanted sensors, IoT is changing every aspect of daily life, especially recent applications in digital healthcare. IoT incorporates various kinds of hardware, communication protocols, and services. This IoT diversity can be viewed as a double-edged sword that provides comfort to users but can lead also to a large number of security threats and attacks. In this survey paper, a new compacted and optimized architecture for IoT is proposed based on five layers. Likewise, we propose a new classification of security threats and attacks based on new IoT architecture. The IoT architecture involves a physical perception layer, a network and protocol layer, a transport layer, an application layer, and a data and cloud services layer. First, the physical sensing layer incorporates the basic hardware used by IoT. Second, we highlight the various network and protocol technologies employed by IoT, and review the security threats and solutions. Transport protocols are exhibited and the security threats against them are discussed while providing common solutions. Then, the application layer involves application protocols and lightweight encryption algorithms for IoT. Finally, in the data and cloud services layer, the main important security features of IoT cloud platforms are addressed, involving confidentiality, integrity, authorization, authentication, and encryption protocols. The paper is concluded by presenting the open research issues and future directions towards securing IoT, including the lack of standardized lightweight encryption algorithms, the use of machine-learning algorithms to enhance security and the related challenges, the use of Blockchain to address security challenges in IoT, and the implications of IoT deployment in 5G and beyond
Towards better understanding of the complex industrial systems: Case of production systems
Growth of the world population and the globalization of trade are the origins of the fourth industrial revolution, called “Industry 4.0”. What engineers call systems are becoming more and more complex as businesses strive to stay competitive and meet ever-changing demand. While automation and information digitization and transmission technologies are increasingly becoming major assets in modern industries, the changes they bring are having an impact on the management of occupational health and safety.
The aim of this article is to provide an overview of the progress achieved in the understanding of complex systems and to test some of the published theory by comparing it to a case study. The major scientific databases were searched to retrieve the literature on complexity, and a large company in the steel products business was queried to determine how its complexity as perceived by its managerial staff compares to the theory of complex systems.
Our main conclusion is that, based on the data gathered in the case study, the perception that the managerial staff has of the company corresponds closely to the current definition of complex systems as proposed by researchers. However, it remains to be determined whether this correspondence holds over the range of business sizes
State of the art and challenges for occupational health and safety performance evaluation tools
In industrialized nations, occupational health and safety (OHS) has been a growing concern in many businesses for at least two decades. Legislation, regulation, and standards have been developed in order to provide organizations with a framework for practicing accident and illness prevention and placing worker well-being at the center of production system design. However, the occurrence of several accidents continues to show that OHS performance evaluation is subject to interpretation. In this review of the literature, we outline the scope of current research on OHS status and performance evaluation and comment on the suitability of the instruments being proposed for field use. This study is based on a keyword-based bibliographical search in the largest scientific databases and OHS-related websites, which allowed us to identify 15 OHS performance evaluation tools. Our principal conclusion is that researchers in the field have shown little interest in generalizing the instruments of OHS performance evaluation and that none of the 15 tools examined is properly applicable to any real organization outside of the sector of activity, economic scale, and jurisdiction for which it was designed
Towards securing machine learning models against membership inference attacks
From fraud detection to speech recognition, including price prediction,
Machine Learning (ML) applications are manifold and can significantly improve
different areas. Nevertheless, machine learning models are vulnerable and are
exposed to different security and privacy attacks. Hence, these issues should be
addressed while using ML models to preserve the security and privacy of the data
used. There is a need to secure ML models, especially in the training phase to
preserve the privacy of the training datasets and to minimise the information
leakage. In this paper, we present an overview of ML threats and vulnerabilities,
and we highlight current progress in the research works proposing defence
techniques against ML security and privacy attacks. The relevant background for
the different attacks occurring in both the training and testing/inferring phases is
introduced before presenting a detailed overview of Membership Inference
Attacks (MIA) and the related countermeasures. In this paper, we introduce a
countermeasure against membership inference attacks (MIA) on Conventional
Neural Networks (CNN) based on dropout and L2 regularization. Through
experimental analysis, we demonstrate that this defence technique can mitigate the
risks of MIA attacks while ensuring an acceptable accuracy of the model. Indeed,
using CNN model training on two datasets CIFAR-10 and CIFAR-100, we
empirically verify the ability of our defence strategy to decrease the impact of MIA
on our model and we compare results of five different classifiers. Moreover, we
present a solution to achieve a trade-off between the performance of the model and
the mitigation of MIA attack
Nuclear Alpha-Particle Condensates
The -particle condensate in nuclei is a novel state described by a
product state of 's, all with their c.o.m. in the lowest 0S orbit. We
demonstrate that a typical -particle condensate is the Hoyle state
( MeV, state in C), which plays a crucial role for
the synthesis of C in the universe. The influence of antisymmentrization
in the Hoyle state on the bosonic character of the particle is
discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle
state, therefore, are predominant. It is conjectured that -particle
condensate states also exist in heavier nuclei, like O,
Ne, etc. For instance the state of O at MeV
is identified from a theoretical analysis as being a strong candidate of a
condensate. The calculated small width (34 keV) of ,
consistent with data, lends credit to the existence of heavier Hoyle-analogue
states. In non-self-conjugated nuclei such as B and C, we discuss
candidates for the product states of clusters, composed of 's,
triton's, and neutrons etc. The relationship of -particle condensation
in finite nuclei to quartetting in symmetric nuclear matter is investigated
with the help of an in-medium modified four-nucleon equation. A nonlinear order
parameter equation for quartet condensation is derived and solved for
particle condensation in infinite nuclear matter. The strong qualitative
difference with the pairing case is pointed out.Comment: 71 pages, 41 figures, review article, to be published in "Cluster in
Nuclei (Lecture Notes in Physics) - Vol.2 -", ed. by C. Beck,
(Springer-Verlag, Berlin, 2011
Influence of physical attributes and pedotransfer function for predicting water retention in management systems
Effects of olive oil and its minor phenolic constituents on obesity-induced cardiac metabolic changes
<p>Abstract</p> <p>Background</p> <p>Olive oil and its minor constituents have been recommended as important dietary therapeutic interventions in preventive medicine. However, a question remains to be addressed: what are the effects of olive oil and its phenolic compounds on obesity-induced cardiac metabolic changes?</p> <p>Methods</p> <p>Male Wistar rats were divided into two groups (<it>n </it>= 24/group): (C) receiving standard-chow; (Ob) receiving hypercaloric-chow. After 21 days C and Ob groups were divided into four subgroups (<it>n </it>= 6/group):(C) standard-chow and saline; (C-Olive)standard-chow and olive-oil (3.0 g/kg.day); (C-Oleuropein)standard-chow and oleuropein (0.023 mg/kg/day); (C-Cafeic) standard-chow and cafeic-acid (2.66 mg/kg/day); (Ob)receiving hypercaloric-chow and saline;(Ob-Olive) hypercaloric-chow and olive-oil;(Ob-Oleuropein) hypercaloric-chow and oleuropein;(Ob-Cafeic) hypercaloric-chow and cafeic-acid. Treatments were given twice a week during 21 days.</p> <p>Results</p> <p>After 42 days, obesity was evidenced in Ob rats from enhanced body-weight, surface-area, and body-mass-index. Energy-expenditure, oxygen consumption(VO<sub>2</sub>) and fat-oxidation were lower in Ob-group than in C. Despite no morphometric changes, Ob-Olive, Ob-Oleuropein and Ob-Cafeic groups had higher VO<sub>2</sub>, fat-oxidation, myocardial beta-hydroxyacyl coenzyme-A dehydrogenase and lower respiratory-quotient than Ob. Citrate-synthase was highest in Ob-Olive group. Myocardial lipid-hydroperoxide(LH) and antioxidant enzymes were unaffected by olive-oil and its compounds in obesity condition, whereas LH was lower and total-antioxidant-substances were higher in C-Olive and C-Oleuropein than in C.</p> <p>Conclusions</p> <p>The present study demonstrated for the first time that olive-oil, oleuropein and cafeic-acid enhanced fat-oxidation and optimized cardiac energy metabolism in obesity conditions. Olive oil and its phenolic compounds improved myocardial oxidative stress in standard-fed conditions.</p
An Inserted α/β Subdomain Shapes the Catalytic Pocket of Lactobacillus johnsonii Cinnamoyl Esterase
Microbial enzymes produced in the gastrointestinal tract are primarily responsible for the release and biochemical transformation of absorbable bioactive monophenols. In the present work we described the crystal structure of LJ0536, a serine cinnamoyl esterase produced by the probiotic bacterium Lactobacillus johnsonii N6.2.We crystallized LJ0536 in the apo form and in three substrate-bound complexes. The structure showed a canonical α/β fold characteristic of esterases, and the enzyme is dimeric. Two classical serine esterase motifs (GlyXSerXGly) can be recognized from the amino acid sequence, and the structure revealed that the catalytic triad of the enzyme is formed by Ser(106), His(225), and Asp(197), while the other motif is non-functional. In all substrate-bound complexes, the aromatic acyl group of the ester compound was bound in the deepest part of the catalytic pocket. The binding pocket also contained an unoccupied area that could accommodate larger ligands. The structure revealed a prominent inserted α/β subdomain of 54 amino acids, from which multiple contacts to the aromatic acyl groups of the substrates are made. Inserts of this size are seen in other esterases, but the secondary structure topology of this subdomain of LJ0536 is unique to this enzyme and its closest homolog (Est1E) in the Protein Databank.The binding mechanism characterized (involving the inserted α/β subdomain) clearly differentiates LJ0536 from enzymes with similar activity of a fungal origin. The structural features herein described together with the activity profile of LJ0536 suggest that this enzyme should be clustered in a new group of bacterial cinnamoyl esterases
Charge transport limited by grain boundaries in polycrystalline octithiophene thin film transistors
Organic filed-effect transistor (OFETs) based on polycrystalline “octithiophene”
has been realized. The current-voltage characteristics at low drain voltage has been used to
derive the mobility of organic field effects transistors (OFETs). It appears that the data
must be corrected for the substantial source and drain contact resistance. The carrier
mobility is found to increase quasi linearly with gate voltage at room temperature. The
temperature dependent measurements show that the mobility is thermally activated and becomes
practically temperature independent at low temperatures. A model based on trapping
mechanism, in which it is assumed that charge transport is limited by grain boundaries, has
been used to describe the carrier mobility in polycrystalline “octithiophene” thin film
transistors measured at temperatures ranging from 10 K to 300 K
Composition dependence of physical properties in Pr 0.7 Ca 0.3 Mn 1−x Ni x O 3
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