Coherent Analysis Research Articles

Generation and coherent characteristics analysis of laser phase modulation spectrum by cascaded phase modulators

Generation and coherent characteristics analysis of laser phase modulation spectrum by cascaded phase modulators

A Systematic Literature Review of Routine Activity Theory’s Applicability in Cybercrimes

Cybercrimes are increasing at an alarming rate and cause detrimental effects to the victims. Routine Activity Theory (RAT) is commonly used to understand the factors influencing cybercrime victimization. However, there have been inconsistent findings on the applicability of RAT theory. This study performs a Systematic Literature Review analysis to consolidate and provide a coherent analysis of the related studies employing RAT theory for cybercrime victimization. The articles were also differentiated based on the cybercrimes topologies being investigated; (a) cybercrime dependent (hacking and malware) and (b) cybercrime enabled (phishing, fraud and identity theft). The findings suggest that a refined specification and operationalization of RAT’S construct tailoring to the types of cybercrimes can arguably yield more accurate application and interpretation of RAT Theory in cybercrimes. Consequently, this will address the inaccurate measurement issues of some of the RATS’s constructs, leading to inconclusive effects on cybercrime victimization. In addition, there is a need for more longitudinal studies to disentangle the effect of RAT’s construct during pre and post cybercrimes. Security advocates can apply the findings of this research to formulate relevant cybercrime awareness programs. The findings also shed some insights into which groups should be targeted for different cybercrime educational and awareness programs. This study can increase the awareness among citizens in terms of their online activities, their attributes and the types of protection from becoming cybercrime victims.

Spin symmetry energy and equation of state of spin-polarized neutron star matter

The equation of state (EOS) of spin-polarized nuclear matter (NM) is studied within the Hartree-Fock (HF) formalism using the realistic density-dependent nucleon-nucleon interaction. With a nonzero fraction $\mathrm{\ensuremath{\Delta}}$ of spin-polarized baryons in NM, the spin- and spin-isospin dependent parts of the HF energy density give rise to the spin symmetry energy that behaves in about the same manner as the isospin symmetry energy, widely discussed in the literature as the nuclear symmetry energy. The present HF study shows a strong correlation between the spin symmetry energy and nuclear symmetry energy over the whole range of baryon densities. The important contribution of the spin symmetry energy to the EOS of the spin-polarized NM is found to be comparable with that of the nuclear symmetry energy to the EOS of the isospin-polarized or asymmetric (neutron-rich) NM. Based on the HF energy density, the EOS of the spin-polarized ($\ensuremath{\beta}$-stable) $npe\ensuremath{\mu}$ matter is obtained for the determination of the macroscopic properties of neutron stars (NS). A realistic density dependence of the spin-polarized fraction $\mathrm{\ensuremath{\Delta}}$ has been suggested to explore the impact of the spin symmetry energy on the gravitational mass $M$ and radius $R$, as well as the tidal deformability of NS. Based on the empirical constrains inferred from a coherent Bayesian analysis of gravitational wave signals of the NS merger GW170817 and the observed masses of the heaviest pulsars, the present study shows the strong impact of the spin symmetry energy $W$, nuclear symmetry energy $S$, and nuclear incompressibility $K$ on the EOS of nucleonic matter in magnetar.

On the peculiar long-term orbital evolution of the eclipsing accreting millisecond X-ray pulsar SWIFT J1749.4 − 2807

ABSTRACT We present the pulsar timing analysis of the accreting millisecond X-ray pulsar SWIFT J1749.4 − 2807 monitored by NICER and XMM–Newton during its latest outburst after almost 11 yr of quiescence. From the coherent timing analysis of the pulse profiles, we updated the orbital ephemerides of the system. Large phase jumps of the fundamental frequency phase of the signal are visible during the outburst, consistent with what was observed during the previous outburst. Moreover, we report on the marginally significant evidence for non-zero eccentricity (e ≃ 4 × 10−5) obtained independently from the analysis of both the 2021 and 2010 outbursts and we discuss possible compatible scenarios. Long-term orbital evolution of SWIFT J1749.4 − 2807 suggests a fast expansion of both the NS projected semimajor axis (x), and the orbital period (Porb), at a rate of $\dot{x}\simeq 2.6\times 10^{-13}\, \text{lt-s}\, \text{s}^{-1}$ and $\dot{P}_{\rm orb}\simeq 4 \times 10^{-10}\, \text{s}\, \text{s}^{-1}$, respectively. SWIFT J1749.4 − 2807 is the only accreting millisecond X-ray pulsar, so far, from which the orbital period derivative has been directly measured from appreciable changes on the observed orbital period. Finally, no significant secular deceleration of the spin frequency of the compact object is detected, which allowed us to set a constraint on the magnetic field strength at the polar caps of BPC < 1.3 × 108 G, in line with typical values reported for AMXPs.

Transient nature of secondary vortices in an axial compressor stage with a tandem rotor

An efficient and compact design of a compressor continues to be a challenging area of research. The unavoidable streamwise adverse pressure gradient together with passage transverse pressure gradient restricts the maximum allowable blade turning. Tandem blading is an interesting concept for increasing the pressure rise by permitting a higher blade turning angle. The energized flow through the tandem blade nozzle gap helps to minimize the possibility of flow separation over the suction surface of the aft blade. However, a coherent transient analysis of a tandem rotor stage in an axial compressor is yet to be well explored. In the present paper, the complex flow field over a tandem rotor and the succeeding stator passage is analyzed in detail. Although the tandem rotor increases the flow turning and diffusion effect, the presence of separate trailing edge wakes and hub corner vortex causes early onset of flow separation over the stator suction. The flow structures developed within the rotor and the stator passages at different time instances are highlighted with the help of limiting streamlines and iso-surface Q-criterion superimposed with entropy contours. The results indicate that within the rotor passage, transient flow features are observed near the hub corner region close to the aft blade trailing edge rather than the tip region. When the rotor passes the stator leading edge, the rotor trailing edge leakage flow at the hub is entrained into the stator leading edge reverse flow region. This is then further circumferentially dragged into the mid-passage region. The interference of multiple rotor wakes with the stator leading edge leads to the formation of longitudinal and arch like separation vortices at the stator-hub and the stator-casing regions, respectively. These separation vortices grow in size while being convected downstream. Eventually, as time progresses, the vortices split and shed periodically from the stator surface. The present investigation highlights the requirement of a new stator design in a tandem rotor–conventional stator configuration. Such designs could further magnify the significant aerodynamic performance obtained using a tandem configuration.

Remodeling of the bioelectric activity of the brain in the outcome of cortical resection

Background: The total scalp electrorencephalography shows the activity of groups of cortical neurons. But each of these groups does not exist in isolation, but they are influenced by other areas, both cortical and subcortical systems of the brain. In the course of neurosurgical treatment, patients underwent resection of cortical areas in which the epileptiform focus was located. In patients with resection of the temporal lobe with structural drug-resistant epilepsy, EEG patterns of loss of activity are not recorded above the remote areas.
 Aim: to study the mechanisms underlying the formation of electrorencephalography patterns recorded in the projection of the resected temporal lobe of the brain in patients operated on for focal drug-resistant epilepsy.
 Materials and methods: There were examined 22 patients with structural pharmacoresistant epilepsy. Coherent analysis of the electrorencephalography was performed for an epoch of 30 seconds in transverse and longitudinal intrahemispheric pairs of leads.
 Results: Correlation interactions between the temporal leads and their surrounding areas are enhanced after removal of the temporal lobe involved in the epileptic system.
 Conclusion: The activity recorded in the postoperative period in the projection area on the scalp of the resected area is formed as a result of signal transmission from other departments.

3R measures in facilities for the production of genetically modified rodents.

Sociocultural changes in the human-animal relationship have led to increasing demands for animal welfare in biomedical research. The 3R concept is the basis for bringing this demand into practice: Replace animal experiments with alternatives where possible, Reduce the number of animals used to a scientifically justified minimum and Refine the procedure to minimize animal harm. The generation of gene-modified sentient animals such as mice and rats involves many steps that include various forms of manipulation. So far, no coherent analysis of the application of the 3Rs to gene manipulation has been performed. Here we provide guidelines from the Committee on Genetics and Breeding of Laboratory Animals of the German Society for Laboratory Animal Science to implement the 3Rs in every step during the generation of genetically modified animals. We provide recommendations for applying the 3Rs as well as success/intervention parameters for each step of the process, from experiment planning to choice of technology, harm-benefit analysis, husbandry conditions, management of genetically modified lines and actual procedures. We also discuss future challenges for animal welfare in the context of developing technologies. Taken together, we expect that our comprehensive analysis and our recommendations for the appropriate implementation of the 3Rs to technologies for genetic modifications of rodents will benefit scientists from a wide range of disciplines and will help to improve the welfare of a large number of laboratory animals worldwide.

Methodology for Consequence Analysis of Future Mobility Scenarios: The SPROUT Framework

The various social, political, environmental, and economical mega-trends together with the rapid rise of digitalization are shaping cities worldwide including the way that citizens and products move within the urban environment. New mobility services are popping up which are showing the path toward more on-demand and personalized mobility patterns. The transformation of the urban mobility environment though constitutes a great challenge for policy-makers, as little is known about the impact of these trends on the city’s current mobility environment while the assessment of the future state of a mobility system can be considered a quite complex process taken its multi-parametric and multi-dimensional nature. This paper aims to simplify this process by presenting a coherent multi-actor consequence analysis framework as a tool for assessing future mobility scenarios which was developed in the framework of the H2020 SPROUT. This paper presents in detail the main components of this framework together with the list of key performance indicators used for assessing the performance in terms of sustainability of future mobility scenarios as well as indicative results from its use by the city of Padua.

Experimental investigation on the unsteady pressure pulsation and vibration of a nuclear pump test loop

AbstractThe nuclear reactor coolant pump (RCP) is the key equipment of the Pressurized Water Reactor, of which the coolant circulation inherently brings flow fluctuation and, therefore, flow‐induced vibration exists, which is detrimental to the safe and stable operation of nuclear power plants. Experiments were carried out on a nuclear pump test loop to investigate the characteristics of pressure pulsation and vibration under various rotational speeds and operational temperatures. Signals of pressure pulsation and vibration synchronously measured from the sensors located among the test loop and the bottom of the motor were analyzed by the Root Mean Square and the Fast Fourier Transform methods. Pronounced pressure pulsation peaks corresponding to the blade passage frequency and its higher harmonics are captured, and pressure pulsation amplitude variations are closely associated with the sensor positions and operating conditions. Vibration magnitude along the outlet direction of the nuclear RCP is the largest and increases with the increasing rotational speed but not the operating temperature. Finally, a coherent analysis was conducted between the vibration at the bottom of the motor and the unsteady pressure pulsation in the test loop. This study can provide meaningful scientific guidance in practical engineering applications.

Vertical propagation of submeso and coherent structure in a tall and dense amazon forest in different stability conditions. PART II: Coherent structures analysis

Observations of the vertical structure of the turbulent flow in different stability regimes above and within the Amazon Forest at the Amazon Tall Tower Observatory (ATTO) site have been presented in Part I. Here, the influence of stability on the inception and development of coherent structures is investigated. According to the mixing-layer analogy the coherent vortices that dominate the turbulent flows at the canopy-atmosphere interface are generated by hydrodynamical instabilities triggered by an inflection in the vertical profile of the mean wind speed at or near the canopy top. The coherent motions time, Tpeak and separation length scale, Λ, depend on the shear length scale, Ls, close to the canopy top. The present analysis studies the characteristics of Ls, Tpeak and Λ in the five stability regimes defined in Part I.The behaviour of Ls with stability is evaluated and parameterized. Ls increases with decreasing stability, presenting two asymptotes for large unstable and stable stratification and a linear behaviour close to neutral stratification. Coherent structures and their timescale are detected with an original method based on the autocorrelation functions of 5-min subsets of turbulent quantities. The vertical time scale is larger in neutral conditions and decreases for both increasing and decreasing stability. At the canopy top the separation length scale presents a linear dependence on Ls, whose slope is maximum in neutral conditions and decreases departing from neutrality. An original parameterization of the dependence of this slope on h/L, where h is the canopy height and L is the Obukhov length, is shown. Combining the parameterizations, the dependence of the separation length scale is finally presented. Λ has a maximum for slightly unstable conditions, linearly decreases towards neutral and weakly stable stratifications and then it tends to zero for very intense unstable and stable stratifications.

New Readings in Arabic Historiography from Late Medieval Egypt and Syria. Proceedings of the Themed Day of the Fifth Conference of the School of Mamluk Studies. Edited by Jo Van Steenbergen and Maya Termonia

The Ayyubid and Mamluk periods witnessed a sharp rise in the production of historical texts, reaching a peak in the first half of the fifteenth century, as well as a transformation in style and contents. Historiography became closer to literature, with the use of anecdotes and mirabilia, colloquialisms and dialogues. In addition, the authors of historical works often placed themselves at the centre of their works, with self-referencing becoming more common. The resulting chronicles and biographical dictionaries, from Ibn al-Dawādārī to al-Maqrīzī, from al-Jazarī to Ibn Ḥajar al-ʿAsqalānī, have fundamentally shaped how we view the history of Egypt and Syria in the Islamic era. This volume represents a comprehensive, coherent and sophisticated analysis of this ‘ “explosion” of historical writing’ in the late medieval period. All thirteen chapters approach the historiographical texts not as mines of information, but as authored texts that demand scrutiny for their own sake, representing...

Defining Conjunto Quantitatively: Classical and Modernist Styles in a Texas-Mexican Genre

Defining <i>Conjunto</i> Quantitatively: Classical and Modernist Styles in a Texas-Mexican Genre

Urban Settlement and Behavioural Exchange towards Environmental Policy among Urban Settlers in Southeast Nigeria: Implications for Environmental Policy Administration and Sustainability

Environmental pollution as well as sustainability of the natural environment is the product of behavioural exchange obtainable in a particular geographical setting and time space. Each environmental setting has its own expected behavioural disposition making it, more or less the symbolic identity of the people living in the setting. In southeast Nigeria among the six geopolitical zones of the country, environmental pollution has appeared as identity for many cities over the years. While some scholars have scratched the matter from other dimensions, there is yet to be research design, targeting the essence of symbolic behavioural exchange in the understanding of the issue of urbanites and environmental pollution. From the theoretical framework of symbolic interactionism, a coherent analysis was advanced in this study, to capture the behavioural exchanges towards the natural environment between the urbanites and the government institutions implementing environmental protection policies. This was substantiated through the primary data obtained via survey research design, involving 640 respondents (18+) from the southeast Nigerian cities. The study adopted descriptive statistics as well as linear model in probing the data collected. According to the findings of the study, weak policy framework and implementation elicited covert anti-environmental protection behaviour. Commitment to environmental protection, policy awareness and support to government policy and institution are dependent on the public trust of the government institutions managing the environment, awareness of environmental issues, government policies and the functionality of the government institutions managing environmental issues.

Size and stoichiometric dependence of thermal conductivities of InxGa1-xN: A molecular dynamics study

The thermal conductivities κ of wurtzite InxGa1-xN are investigated using equilibrium molecular dynamics (MD) method. The κ of InxGa1-xN rapidly declines from InN (κInN = 141 W/mK) or GaN (κGaN = 500 W/mK) to InxGa1-xN (x≠ or 1), and reaches a minimum (κmin = 19 W/mK) when x is around 0.5 at 300 K. The mean free path (MFP) of InxGa1-xN, ranging from 2 to 5 nm and following the same trend with the κ, is extrapolated in our simulation and a parabolic relationship between x and MFP is established. We find that the κ of InxGa1-xN decreases with increasing temperatures. The evolution of κ of InxGa1-xN is also examined by projecting the momentum-energy relationship of phonons from MD trajectories. The phonon dispersion and phonon density of states for InxGa1-xN reflect a slightly more flattened dispersive phononic curve of the alloying system. Despite an overestimated κ than experimental values, our calculated κ at 300 K agrees well with the results obtained by solving Boltzmann transport equation and also has the same stoichiometric trend with the experimental data. Our study provides the coherent analysis of the effect of thickness, temperature and stoichiometric content on the thermal transport of InxGa1-xN which is helpful for the thermal management of InxGa1-xN based devices.

Electronic reconstruction at the polar (111)-oriented oxide interface

Atomically flat (111) interfaces between insulating perovskite oxides provide a landscape for new electronic phenomena. For example, the graphene-like coordination between interfacial metallic ion layer pairs can lead to topologically protected states [Xiao et al., Nat. Commun. 2, 596 (2011) and A. Rüegg and G. A. Fiete, Phys. Rev. B 84, 201103 (2011)]. The metallic ion/metal oxide bilayers that comprise the unit cell of the perovskite (111) heterostructures require the interface to be polar, generating an intrinsic polar discontinuity [Chakhalian et al., Nat. Mater. 11, 92 (2012)]. Here, we investigate epitaxial heterostructures of (111)-oriented LaAlO3/SrTiO3 (LAO/STO). We find that during heterostructure growth, the LAO overlayer eliminates the structural reconstruction of the STO (111) surface with an electronic reconstruction, which determines the properties of the resulting two-dimensional conducting gas. This is confirmed by transport measurements, direct determination of the structure and atomic charge from coherent Bragg rod analysis, and theoretical calculations of electronic and structural characteristics. Interfacial behaviors of the kind discussed here may lead to new growth control parameters useful for electronic devices.

Tracing the source of unsteady-state low-frequency noise based on wavelet coherence analysis

The original partial coherence analysis method can be used to analyze the contributions between different noise sources and field points under steady-state conditions. Nevertheless, coherence analysis cannot be used to deal with unsteady-state signals because the signals are time-varying. In this paper, the method of panel contribution under unsteady-state conditions based on wavelet coherence analysis is proposed to determine the largest noise contribution in the cab. First, the unsteady-state simulation signals are analyzed by wavelet coherence theory. This step not only verifies the effectiveness but also points out that wavelet coherence is more superior to crossed wavelet. Second, the measured unsteady-state signals of the eight measuring points are processed by time-frequency wavelet coherent analysis. According to the obtained two-dimensional time-frequency diagrams, the contribution of different panels to the noise of measuring field points in the continuous frequency range can be found out. Then, the total contribution coefficient sum of each panel in a certain frequency band is calculated. Finally, the above analysis results are used to determine the panels with the largest contribution to the cab noise. The corresponding noise reduction scheme is also proposed. The results show that the overall sound pressure level is obviously decreased after optimization. The noise in the cab is reduced by 4.5dBA ∼ 7dBA. The effectiveness of this method has been further verified by the above results.

Refining the Bayesian Approach to Unifying Generalisation

Tenenbaum and Griffiths (Behavioral and Brain Sciences 24(4):629–640, 2001) have proposed that their Bayesian model of generalisation unifies Shepard’s (Science 237(4820): 1317–1323, 1987) and Tversky’s (Psychological Review 84(4): 327–352, 1977) similarity-based explanations of two distinct patterns of generalisation behaviours by reconciling them under a single coherent task analysis. I argue that this proposal needs refinement: instead of unifying the heterogeneous notion of psychological similarity, the Bayesian approach unifies generalisation by rendering the distinct patterns of behaviours informationally relevant. I suggest that generalisation as a Bayesian inference should be seen as a complement to, instead of a replacement of, similarity-based explanations. Furthermore, I show that the unificatory powers of the Bayesian model of generalisation can contribute to the selection of one of these models of psychological similarity.

Lagrangian Coherent Structure Analysis on the Vegetated Compound Channel with Numerical Simulation

Natural channels often consist of a mainstream near their thalwegs and shallow vegetated areas near shores. The compounded and partially vegetated cross-sections play a significantly role in determining the hydrodynamic characteristics of a channel. By employing the Lagrangian Coherent Structure (LCS) analysis, the present work unravels the effect of vegetation and geometry on the hydrodynamic interactions between mainstreams with the various depths and vegetated shallow areas. The LCS method is the concept of dynamical system analyses, which is determined by the finite-time Lyapunov exponents (FTLE) field of fluid particles. It enables to overcome the limitations of using the particle tracking method in cost and time for simulations. Since the LCSs represent material surfaces or asymptotic lines which particles approach, but do not pass through, they match well with the trajectories of particles or materials obtained by solving particle motion equations. Therefore, the temporal and spatial developments of the interfacial layers could be investigated by using the FTLE. As the difference of depth becomes appreciable, the values of FTLE are relatively larger farther from the vegetated area. It implies that the interfacial layer becomes wider with the larger size of vortex produced by the differences of velocities between the mainstreams and the vegetated areas. In other words, as depth differences become large, materials and momentum can be spread from the vegetated area to or collected from a wider area of the mainstream.

НЕЙРОФІЗІОЛОГІЧНІ МЕХАНІЗМИ ЗДІЙСНЕННЯ ПРОСТОЇ СЕНСОМОТОРНОЇ РЕАКЦІЇ У ВІЙСЬКОВОСЛУЖБОВЦІВ РІЗНОГО ВІКУ

Introduction.For different types of professional activity, the speed of information processing is one of the most important indicators of performance. It is well known that aging is accompanied by changes in the speed and / or mode of information processing in the brain. Simple sensorimotor reaction (SMR) shows speed and efficiency of information perception processes, its integration and is and reveals how well the basic cognitive mechanisms can be involved in the implementation of target tasks. Purpose.The aim of this work was to investigate the rate of SMR in different age groups and to identify age-related changes in neural networks that promote task performance.Methods.The survey involved 34 right-handed volunteers, aged 18-54, without health complaints - representatives of various military professions (mechanics, shooters, drivers, radar operators, anti-aircraft missile officers, communications, tablets, pilots and conscripts), which were divided into three age groups (1 group - 18-23 years, n = 11; 2 group - 24-34 years, n = 15; 3 group - 35- 54 years, n = 8). SMR was determined using a specialized computer program and while its performance 19 electrode EEG was recorded. Remote synchronization of brain areas was determined using coherent analysis in Neuron-Spectrum-4 / VP complex («NeuroSoft»). Reliable synchronization was determined only for those pairs of leads for which the median was ≥ 0.7.Results.Although the comparative analysis of the PSMR rate in the three groups according to the Kruskal-Wallis test did not reveal significant differences (Kruskal-Wallis test: H (2, N = 54) = 0.889; p = 0.64), coherent analysis of electroencephalograms, which were recorded during task, revealed that there were differences in the neural mechanisms of SSMR between the three age groups. We showed age-related increases in activation of the left secondary visual cortex, while activation of the left frontal lobe decreasedwhich may indicate shift from the strategic system of response to the system of informative features selection and constant attention maintenance. In the third group coherence in the theta range between the prefrontal area and the postcentral gyrus was the strongest in comparison with the first and second groups, which may indicate an increase in the role of visual selective attention with age, as well as greater effort and concentration to perform the task. Also there was an age-related increase in the alpha range coherences and decrease in the delta range, which may indicate shift from the general setting to the input information flow to local highly specific information processing.Originality. Age-related adaptive changes of the neural networks that enable effective performance of the SSMR: different strategies of visual-motor reaction are revealed.72 Серія «Біологічні науки», 202 2Conclusions. Performance of the SSMR test involves different neuronal strategies that were determined for three age groups. The prospect of further research is to determine age-related differences in the chronometric indicators and neuronal mechanisms for SSMR, choice reaction and other psychophysiological tests for different military specialties and according to acquired data create guidelines for conducting surveys to ensure effective performance of work responsibilities with age. Key words: simple sensorimotor reaction; electroencephalogram; coherent analysis; age-related changes; professional selection

A Novel Sea Clutter Rejection Algorithm for Spaceborne Multichannel Radar Systems

Due to the high-speed movement of a spaceborne radar (SBR) platform, the geographic clutter spectrum expands severely, resulting in the useful moving target signal submerged by the main-lobe clutter background. To deal with this issue, the equipped multichannel arrays in an SBR system provide sufficient spatial degrees, and as a consequence, the space-time adaptive processing (STAP) technology is often preferred to achieve the moving target detection, even in the main-lobe clutter regions. However, for the moving target detection under the sea scene, due to the complex internal motion of sea clutter, the clutter signal received by an SBR system may possess the space- and time-varying characteristics, worsening the multichannel clutter rejection performance using the traditional STAP techniques. In this article, a novel sea clutter suppression method based on the joint space-time-frequency adaptive filtering is proposed. In the proposed algorithm, according to the coherent time analysis of sea clutter, the subaperture time-domain sliding window is employed to alleviate the clutter decorrelation effect, and then, a modified subspace projection technique is applied to accomplish the first-stage clutter rejection. After realizing the effective signal recovery with respect to these residual subaperture clutter data, the second-stage spatial filtering method is applied to realize the final clutter suppression with respect to the relatively high Doppler resolution clutter returns. The effectiveness of the proposed algorithm is verified by both simulated multichannel sea clutter data and real-measured sea clutter data.