Entropy Variation Research Articles

Entropy-based distributed denial of service attack detection in software-defined networking

Software defined networking (SDN) is a new network architecture that allows for centralized network control. The separation of the data plane from the control plane, which establishes a programmable network environment, is the key breakthrough underpinning SDN. The controller facilitates the deployment of services that specify control policies and delivers these rules to the data plane using a common protocol such as OpenFlow at the control plane. Despite the many advantages of this design, SDN security remains a worry because the aforementioned chapter expands the network's attack surface. In fact, denial of service (DoS) assaults pose a significant threat to SDN settings in a variety of ways, owing to flaws in the data and control layers. This work shows how distributed denial of service (DDoS) attack detection is based on the entropy variation of the destination IP address. The study takes advantage of the OpenFlow protocol's (OFP) flexibility and an OpenFlow controller (POX) to apply the proposed method. An entropy computation to determine the distributed features of DDoS traffic is developed and it is capable of detecting a user datagram protocol (UDP) flood attack after 0.445 seconds this type of attack occurred.

Magnetocaloric La(Fe,Mn,Si)13Hz particles and their chemical stability in heat transfer fluids employed in magnetic refrigeration

La(Fe,Mn,Si)13Hz alloys are prominent solid-state refrigerants for magnetic refrigeration, given their outstanding magnetocaloric properties. However, their chemical stability is yet an issue to be further investigated, especially under the working conditions of magnetic refrigerators. These alloys should not corrode nor lose their magnetocaloric capabilities when in contact with the heat transfer fluids used in magnetic refrigeration. Such topics are addressed in this work by performing immersion tests with La(Fe,Mn,Si)13Hz particles in two kinds of media: deionized water and deionized water containing a corrosion inhibitor (Entek), the latter medium being an usual heat transfer fluid for magnetic refrigeration. Corrosion products were detected at the surface of the particles after just 15 min of exposure in water in the absence of the inhibitor, and corrosion progressed over time, increasing the pH in the surroundings of the particles. After 10 weeks, there were clear signs of surface damage, and the fraction of oxygen at the surface increased from about 2% wt. up to 12% wt. Consequently, the thermomagnetic properties changed as well: the Curie temperature of the particles was shifted to higher values (increased about 1.5%), and the magnetic transition was smeared out. A significant decrease in the variation of specific entropy was also observed: depending on the initial TC of the particles, such decrease was as high as 44,5% (from 8.1 J/kg∙K before the immersion test to 4.5 J/kg∙K after 10 weeks of immersion). In contrast, no changes were observed in the particles exposed to water containing the corrosion inhibitor for the same period: their microstructure remained stable, the pH of the exposure media did not vary significantly, and their thermomagnetic behaviour remained unchanged. Therefore, the presence of the inhibitor effectively avoided the occurrence of aqueous corrosion and preserved the microstructure and thermomagnetic properties of the La(Fe,Mn,Si)13Hz particles.

Switchable Piezoelectricity of Polyvinylidene Fluoride Films Induced by Crystal Transition in Shape Memory Process.

With the rapid development of wearable self-powered devices, the piezoelectric materials having deformable and switchable characteristics are attracting extensive attention. Herein, the cross-linked polyvinylidene fluoride (cPVDF) was fabricated through an alkali-catalyzed defluorination and chemical cross-linking method by introducing trimethylhexamethylenediamine (THDA). The system filled with 1 wt % THDA (CP1) was proved to possess balanced cross-linking density and crystallinity, which would play a crucial role in achieving a switchable piezoelectric effect. In comparison to pristine PVDF, the cross-linked one exhibited repeatable shape memory characterization due to restrained plastic deformation above the melting transition. Both the shape-fixing and shape-recovery ratios were stably maintained above 90%. More significantly, the thermo-mechanical program also triggered the α-β-α crystal transition accompanied by the variation of conformational entropy. The largest amount of β crystals was produced in the temporary shape, whereas the original and recovery shapes were dominated by α crystals. Such structural transition occurred repeatedly in the successive shape memory cycles, which thereby induced the periodic fluctuation of the piezoelectric constant (d33). For the CP1 sample, its d33 was only about 2 pC/N in the original and recovery shapes but reached up to 9.4 pC/N in the temporary shape. When the latter one was fabricated into a piezoelectric device, alternating voltage and current were generated by performing periodic impact force and were demonstrated to be capable of monitoring some pressure-related motions in real time without an external power supply. Finally, the switchable piezoelectric effect of the CP1 at different shape memory stages was further revealed through its electroactive response to the sinusoidal voltage stimulation. This work offers a special perspective in tailoring piezoelectric performance through the structural transition in shape memory progress, which is of great significance for enriching the types and applications of piezoelectric polymers.

Kinetic and Thermodynamic Study of Extraction of Oleoresin Containing Curcuminoids from Turmeric (Curcuma Longa L.)

Numerous studies are nowadays undertaken across the world laboratories on turmeric and show its excellent virtues in various fields such as medicine, pharmacology, cosmetics, and so forth. In this paper, to enlarge the domain of scientific knowledge, a kinetic and thermodynamic behavior of curcuminoid extraction from Curcuma longa L has been investigated in the dilute medium using ethanol as solvent under a magnetic stirrer. Through the KUNYIMA method, by means of the KUNYIMA first law, the global kinetic constant has been calculated at 250 rounds per minute (rpm) and the data have shown its Constance at 500 rounds per minute at the same temperature (27.5 °C). The kinetic constant can serve to build a commercial tank of production of curcuminoids using the sizing factor to endow the Democratic Republic of the Congo with its home technology of curcuminoids extraction as is hereby discussed. Extraction enthalpy and entropy have been calculated in a closed system using the Arrhenius relation. The results of enthalpy indicate that the extraction of curcuminoids is an endothermic phenomenon. This endothermic behavior of the extraction of curcuminoids in ethanol under a magnetic stirrer probably suggests the predominance of the enol form of curcumin in presence of its tautomeric ketone form. Also, the extraction of curcuminoids in ethanol is an endothermic phenomenon and this last phenomenon probably suggests its non-bioavailability. The energy promoting solubilization of curcuminoids arises from the solvent, under a magnetic stirrer, that can meet its alike with the hydroxyl group (like dissolves like). The value of the variation of entropy has evidently suggested the disturbance of the natural order after extraction. Note that KUNYIMA's second law has been hereby announced.

Physical insight into the entropy-driven ion association.

The ion association is widely believed to be dominated by the favorable entropy change arising from the release of water molecules from ion hydration shells. However, no direct thermodynamic evidence exists to validate the reliability and suitability of this view. Herein, we employ complicated free energy calculations to rigorously split the free energy including its entropic and enthalpic components into the water-induced contributions and ion-ion interaction terms for several ion pairs from monatomic to polyatomic ions, spanning the size range from small kosmotropes to large chaotropes (Na+ , Cs+ , Ca2+ , F- , I- , CO3 2- , and HPO4 2- ). Our results successfully reveal that though ion associations are indeed determined by a delicate balance between the favorable entropy variation and the repulsive enthalpy change, the entropy gain dominated by the solvent occurs only for the monatomic ion pairing. The water-induced entropic contribution significantly goes against the ion pairing between polyatomic anion and cation, which is, alternatively, dominated by the favorable entropy from the ion-ion interaction term, due to the configurational arrangement of polyatomic anions involved in ion association. The structural and dynamic analysis demonstrates that the entropy penalty from the water phase is primarily ascribed to the enhanced stability of water molecules around the cation imposed by the incoming anion. Our study successfully provides a fundamental understanding of water-mediated ion associations and highlights disparate lengthscale dependencies of the dehydration thermodynamics on the specific types of ions.

Spatiotemporal evolution characteristics of coordinated development of urbanization and ecological environment in eastern Russia-Perspectives from the 3D global trend and 2D plane analysis.

Under the background of "the Belt and Road" and "the economic corridor of China, Mongolia and Russia" initiatives, it has great value to study the temporal and spatial evolution characteristics of the coordinated development between the urbanization and ecological environment in eastern Russia (the Siberian Federal District and the Far East Federal District). In this paper, we studied the urbanization development level, eco-environment development level, and their coupling coordinated development degree during 2005-2018 in the eastern Russia from the perspectives of the 3D global trend and 2D plane analysis. First, combining with the Population-Economic-Sociology and Pressure-State-Response models, the urbanization development level and eco-environment development level were calculated by the comprehensive weighting method of entropy weight and variation coefficient for eastern Russia. Second, the coupling coordinated development degree of the urbanization development level and eco-environment development level was measured by the coupling coordination model for eastern Russia. Finally, the spatial differentiation of the urbanization development level, the eco-environment development level and their coupling coordinated development degree was performed respectively by the 3D global trend and 2D plane analysis using ArcGIS. The results are as following. First, the comprehensive urbanization development level of eastern Russia has increased from 2005 to 2018, and the economic urbanization is the main factor that affects the urbanization development in eastern Russia. The comprehensive eco-environment development level of eastern Russia has decreased from 2005 to 2018, and the eco-environment pressure is the main factor that affects the eco-environment development in eastern Russia. The coupling coordination degree of the urbanization development and eco-environment development has increased from 2005 to 2018. However, it is still in the uncoordinated stage. Second, from 2005 to 2018, the urbanization development level of the Siberian Federal District is higher than that of the Far East Federal District. The eco-environment development level of the Siberian Federal District is balanced to that of the Far East Federal District. The coupling coordination degree of the Siberian Federal District is higher than that of the Far East Federal District. Among the Siberian and Far East Federal Districts, most of the federal subjects belong to the uncoordinated stage of the urbanization development and the eco-environment development. Third, the urbanization development level, the eco-environment development level, and their coupling coordinated development level are all spatially imbalanced in the eastern Russia, which show the "High West, Low East" and "High Center, Low North and Low South" spatial pattern from the perspectives of the 3D global trend and 2D plane analysis. The areas with high levels are concentrated in the Novosibirsk Region, Altay Territory, Kemerovo Region, Krasnoyarsk Territory, and Irkutsk Region. The areas with low ones are mostly in the Republic of Altay and Chukotka Autonomous Area. Finally, we suggest policies and strategies that can boost the growth and development of the urbanization and the eco-environment in the Sino-Russian border areas.

Identification of Electrochemically Adsorbed Species via Electrochemical Microcalorimetry: Sulfate Adsorption on Au(111).

We investigate compositional changes of an electrochemical interface upon polarization with electrochemical microcalorimetry. From the heat exchanged at a Au(111) electrode upon sulfate adsorption, we determine the reaction entropy of the adsorption process for both neutral and acidic solutions, where the dominant species in solution changes from SO4 2− to HSO4 −. In neutral solution, the reaction entropy is about 40 J mol−1 K−1 more positive than that in acidic solution over the complete sulfate adsorption region. This entropy offset is explicable by a deprotonation step of HSO4 − preceding sulfate adsorption in acidic solution, which shows that the adsorbing species is SO4* in both solutions. The observed overall variation of the reaction entropy in the sulfate adsorption region of ca. 80 J mol−1 K−1 indicates significant sulfate‐coverage dependent entropic contributions to the Free Enthalpy of the surface system.

Investigation of Relation Between Hypoxic-Ischemic Encephalopathy and Spectral Features of Infant Cry Audio

Despite advances in medical technologies, Hypoxic-Ischemic Encephalopathy (HIE) continues to be a problem for neonatal intensive care units. Analysis of crying sounds may be a valuable tool for predicting neonatal disease. However, the characteristics of crying in newborns with HIE are still unclear. One of the factors limiting the ability to focus on that subject is the lack of commercially available infant cry database for research. Also, another reason that complicates the classification is the varying characteristics of infant cry. Accordingly, crying sounds were recorded from 35 infants and demographic characteristics of the study groups are presented as well as the numerical representation of spectral features. Experiments reveal that the existence of HIE causes distinctive variation in energy, energy entropy and spectral centroid features of the utterances; which leads us to conclude that the presented combination of spectral features would function well with any supervised or unsupervised machine learning algorithm.

Magnetic, structural and magnetocaloric properties of Y0.9Gd0.1Fe2Hx hydrides

At 300 K, Y$_{0.9}$Gd$_{0.1}$Fe$_{2}$H$_{x}$ hydrides crystallize sequentially with increasing H concentration in various structures related to a lowering of the cubic MgCu$_{2}$ type structure of the parent alloy: cubic C1, monoclinic M1, cubic C2, monoclinic M2, cubic C3, orthorhombic O. Above 300 K, they undergo a first-order transition at a T$_{O-D}$ temperature driven by order-disorder of hydrogen atoms into interstitial sites. Their magnetic, structural and magnetocaloric properties have been investigated through magnetic measurements, and high-resolution synchrotron diffraction experiments. The magnetization at 5 K decreases slightly from 4 to 3.8 ${\mu}_{B}$ for x = 3 to 3.9 H f.u., then with a larger slope for higher H content. A discontinuous decrease of the magnetic transition temperature is observed: M1 and C2 hydrides are ferrimagnetic with T$_{C}$ near 300 K, M2 hydride displays a sharp ferromagnetic-antiferromagnetic transition at T$_{FM-AFM}$ =144 K, whereas C3 and O hydrides present only a sharp increase of the magnetization below 15 K and a weak magnetization up to RT. Negative magnetic entropy variations (${\Delta}$S$_{M}$) are measured near T$_{C}$ for the M1 and C2 phases, near T$_{FM-AFM}$ for the M2 phase, whereas positive ${\Delta}$S$_{M}$ peaks due to inverse MCE effect are found near T$_{O-D}$. A structural and magnetic phase diagram is proposed.

Application of Two Novel Acoustic Emission Parameters on Identifying the Instability of Granite.

The issue of monitoring and early warning of rock instability has received increasing critical attention in the study of rock engineering. To investigate the damage evolution process of granite under triaxial compression tests, acoustic emission (AE) tests were performed simultaneously. This study firstly introduced two novel parameters, i.e., the coefficient of variation (CoV) of the information entropy and correlation dimension of the amplitude data from the AE tests, to identify the precursor of the failure of granite. Then the relationship between the changes in these parameters and the stress-time curve was compared and analyzed. The results of this study show that: (1) There is a strong correlation between the CoV of the information entropy and the failure process of granite. The granite failed when the CoV curve raised to a plateau, which could be used as an indicator of rock instability. (2) The fluctuation of the correlation dimension indicates the different stages during the loading process, i.e., the initial compaction stage, the linear elastic stage, the yield stage, and the failure stage. Each stage contains a descending and a rising process in the correlation dimension curve, and the exhibited starting point or the bottom point at the correlation dimension curve could be selected as the indicator point for the rock instability. (3) The combined analysis of the Information entropy and Correlation dimension can improve the accuracy of rock instability prediction. This study provides new insights into the prediction of rock instability, which has theoretical implications for the stability of subsurface engineering rock masses.

DECODING THE CORRELATION AMONG LEG MUSCLE AND BRAIN ACTIVATIONS IN DIFFERENT BODY MOVEMENTS

We investigated the correlation among brain and leg muscle activations by analyzing Electroencephalogram (EEG) and Electromyogram (EMG) signals in different conditions. Twelve subjects performed four tasks, including (1) quarter turns, (2) U-turns, (3) bypass obstacles, and (4) repeating quarter turns and U-turns two times. Then, we quantified the alterations of the complexity of these signals by computing the fractal dimension and sample entropy. The results showed that EEG and EMG signals in the case of the first task are more complex than the second task, in which they are more complex than the third task. Furthermore, the brain and muscle signals show the least complexity in the case of the fourth task. Moreover, we found strong correlations in the variations of fractal dimension ([Formula: see text]) and sample entropy ([Formula: see text]) between EEG and EMG signals in various tasks. Therefore, brain and muscle activations are strongly correlated in different tasks. Similar analyses can be conducted in the case of other organs to decode their correlations.

Quantum Thermodynamics of Holographic Quenches and Bounds on the Growth of Entanglement from the Quantum Null Energy Condition

The quantum null energy condition (QNEC) is a lower bound on the energy-momentum tensor in terms of the variation of the entanglement entropy of a subregion along a null direction. To gain insights into quantum thermodynamics of many-body systems, we study if the QNEC restricts irreversible entropy production in quenches driven by energy-momentum inflow from an infinite memoryless bath in two-dimensional holographic theories. We find that an increase in both entropy and temperature, as implied by the Clausius inequality of classical thermodynamics, is necessary but not sufficient to not violate QNEC in quenches leading to transitions between thermal states with momentums that are dual to Banados-Teitelboim-Zanelli geometries. For an arbitrary initial state, we can determine the lower and upper bounds on the increase of entropy (temperature) for a fixed increase in temperature (entropy). Our results provide explicit instances of quantum lower and upper bounds on irreversible entropy production whose existence has been established in literature. We also find monotonic behavior of the nonsaturation of the QNEC with time after a quench, and analytically determine their asymptotic values. Our study shows that the entanglement entropy of an interval of length l always thermalizes in time l/2 with an exponent 3/2. Furthermore, we determine the coefficient of initial quadratic growth of entanglement analytically for any l, and show that the slope of the asymptotic ballistic growth of entanglement for a semi-infinite interval is twice the difference of the entropy densities of the final and initial states. We determine explicit upper and lower bounds on these rates of growth of entanglement.

New guest in the third quantized multiverse

In the present article we point out a conceptual issue of the Third Quantization formalism for Canonical Quantum Gravity. Based on earlier results on interuniversal entanglement, the picture of noninteracting universe-antiuniverse pairs is incomplete. In particular, the variation of the entanglement entropy with the scale factor, understood as a measure of time, implies either an interaction between pairs of universes or universes with a heat bath, i.e. an external field. We propose a simple solution to the problem by adding a new quantum field to the formalism. Correspondingly, particles of this field mediate interactions between universes -- depending on the model at tree level or one loop -- and may further provide a heat bath in the background.

Approximating quantum thermodynamic properties using DFT

The fabrication, utilisation, and efficiency of quantum technology devices rely on a good understanding of quantum thermodynamic properties. Many-body systems are often used as hardware for these quantum devices, but interactions between particles make the complexity of related calculations grow exponentially with the system size. Here we explore and systematically compare ‘simple’ and ‘hybrid’ approximations to the average work and entropy variation built on static density functional theory concepts. These approximations are computationally cheap and could be applied to large systems. We exemplify them considering driven one-dimensional Hubbard chains and show that, for ‘simple’ approximations and low to medium temperatures, it pays to consider a good estimate of the Kohn–Sham Hamiltonian to approximate the driving Hamiltonian. Our results confirm that a ‘hybrid’ approach, requiring a very good approximation of the initial and, for the entropy, final states of the system, provides great improvements. This approach should be particularly efficient when many-body effects are not increased by the driving Hamiltonian.

Effect of alumina on thermodynamic performance of palladium-H2 (D2) system

Palladium (Pd) has a strong hydrogen isotope effect, widely used in the Thermal Cycling Absorption Process (TCAP) separation column. However, due to pulverization and high gas resistance, Pd was usually dispersed in backing materials, such as alumina (Al2O3), to improve the service performance. In this paper, the microstructure of sponge palladium and Pd–Al2O3 pellet was observed by Scanning Electron Microscopy (SEM), and the crystalline structure before and after hydrogeneration was characterized by X-Ray Diffractometer (XRD). To study the support effect of backing material Al2O3 on the hydrogen/deuterium thermal absorption performance of palladium, the pressure-composition-temperature (P–C-T) curves were measured by series experiments. The result shows that Al2O3 acts as a support material between palladium particles to suppress the effect of the pellet expansion-shrinking during H2 (D2) absorption/desorption cycling. Alumina could provide free position for hydrogen atoms. And the inflection points of α phase to α+β phase shift from 0.02 to 0.09 for Pd–Al2O3 pellet/hydrogen system. The entropy and enthalpy variation of Pd/H (Pd/D) system in α+β phase are respectively −18.34 (−16.83) kJ/mol and −45.65 (−42.44) J/mol/K, which show no correlation with alumina. The H-D separation factor positively correlates with the quantity of hydrogen in the solid phase, and alumina could restrain the separation effect.

Entropic force and real-time dynamics of holographic quarkonium in a magnetic field

We continue the study of a recently constructed holographic QCD model supplemented with magnetic field. We consider the holographic dual of a quark, anti-quark pair and investigate its entropy beyond the deconfinement phase transition in terms of interquark distance, temperature and magnetic field. We obtain a clear magnetic field dependence in the strongly decreasing entropy near deconfinement and in the entropy variation for growing interquark separation. We uncover various supporting evidences for inverse magnetic catalysis. The emergent entropic force is found to become stronger with magnetic field, promoting the quarkonium dissociation. We also probe the dynamical dissociation of the quarkonium state, finding a faster dissociation with magnetic field. At least the static predictions should become amenable to a qualitative comparison with future lattice data.

Genetic loci and metabolic states associated with murine epigenetic aging.

Changes in DNA methylation (DNAm) are linked to aging. Here, we profile highly conserved CpGs in 339 predominantly female mice belonging to the BXD family for which we have deep longevity and genomic data. We use a 'pan-mammalian' microarray that provides a common platform for assaying the methylome across mammalian clades. We computed epigenetic clocks and tested associations with DNAm entropy, diet, weight, metabolic traits, and genetic variation. We describe the multifactorial variance of methylation at these CpGs and show that high-fat diet augments the age-related changes. Entropy increases with age. The progression to disorder, particularly at CpGs that gain methylation over time, was predictive of genotype-dependent life expectancy. The longer-lived BXD strains had comparatively lower entropy at a given age. We identified two genetic loci that modulate epigenetic age acceleration (EAA): one on chromosome (Chr) 11 that encompasses the Erbb2/Her2 oncogenic region, and the other on Chr19 that contains a cytochrome P450 cluster. Both loci harbor genes associated with EAA in humans, including STXBP4, NKX2-3, and CUTC. Transcriptome and proteome analyses revealed correlations with oxidation-reduction, metabolic, and immune response pathways. Our results highlight concordant loci for EAA in humans and mice, and demonstrate a tight coupling between the metabolic state and epigenetic aging.

Pyrolysis kinetics, thermodynamics of PTA sludge and product characterization of cyclic in-situ catalytic pyrolysis by using recycled char as a catalyst

Pyrolysis is an effective way for the sludge harmless, reduction treatment and resource utilization. In this study, the pyrolysis kinetics and thermodynamics of PTA sludge was evaluated. Afterword, a cyclic in-situ catalytic pyrolysis of PTA sludge by using recycled char as a catalyst was conducted. The product characterization, e.g. pyrolysis syngas as well as the catalytic effect of pyrolysis char, were analyzed. The results demonstrated that the Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), and Starink model-free methods have good agreement on kinetic parameters, the average activation energy was calculated at 295.18, 286.62, and 290.55 kJ/mol, respectively. Meanwhile, thermodynamic parameters, e.g. the variations in enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG), were evaluated based on the deduced kinetic results, whereby the suitable pyrolysis temperature was determined at 973 K. The results of cyclic in-situ catalytic pyrolysis showed that the pyrolysis char could promote tar cracking, which greatly increased the yield of pyrolysis syngas. After five rounds of in-situ catalytic pyrolysis, the yield of pyrolysis syngas increased from 0.089 L/g to 0.176 L/g and the carbon conversion increased from 24.8% to 36.5%, respectively.

Quantitative approach for snowy feature detection using polarimetric analysis

Synthetic aperture radar is an advanced remote sensing and imaging radar. It plays vital role in acquiring high resolution images of earth surface. The capturing of images by synthetic aperture radar is done in any season immaterial of weather conditions. This paper gives the details of the basic feature extraction for the snow images. The two sample images are analyzed to know the feature details of the object under consideration. Analytical details of variation in entropy and the polarization were considered. The scattering mechanism involved in the snow area is analyzed. The details of snow classification based on its layered structure along with its physical nature like moisture involved are presented. The results indicate a high value of entropy of 0.94 for the snow image. The reason for high entropy is because of more surface uniformity in the snow images. The flat surface structured snow basically exhibits the surface scattering mechanism.

Gradient sensing in Bayesian chemotaxis

Bayesian chemotaxis is an information-based target search problem inspired by biological chemotaxis. It is defined by a decision strategy coupled to the dynamic estimation of target position from detections of signaling molecules. We extend the case of a point-like agent previously introduced (Vergassola et al., Nature (2007)), which establishes concentration sensing as the dominant contribution to information processing, to the case of a circle-shaped agent of small finite size. We identify gradient sensing and a Laplacian correction to concentration sensing as the two leading-order expansion terms in the expected entropy variation. Numerically, we find that the impact of gradient sensing is most relevant because it provides direct directional information to break symmetry in likelihood distributions, which are generally circle shaped by concentration sensing.