Incident Stream Research Articles

Shades of Grey: An Ethical Dilemma

This case refers to an ethical dilemma encountered by the Internal Committee (IC) of a manufacturing corporation in redressing a complaint of sexual harassment raised by an employee against another colleague. The stream of incidents brought to light during the proceedings of the IC brings out the challenges faced by any decision-making authority in figuring out whether an employee alleged with the misconduct of sexual harassment could be guilty in reality. The case thus throws open the question of whether an allegation of sexual harassment is always black-and-white or whether there is any tinge of grey in it.

ИССЛЕДОВАНИЕ ПО УПРАВЛЕНИЮ РИСКАМИ В ОБЛАСТИ ИНФОРМАЦИОННЫХ ТЕХНОЛОГИЙ В КОМПАНИЯХ, ЗАНИМАЮЩИХСЯ ЦЕННЫМИ БУМАГАМИ

The field of information technology is constantly expanding, and the risks associated with it are becoming more and more complex. Risk management in this area is given great attention in the securities industry. The endless stream of risk-related incidents not only led to serious losses for enterprises, but also had a significant impact on the entire securities trading market. Only by continuously improving the management and assessment of information technology risks of securities companies and taking appropriate optimization and improvement measures can the likelihood of risky cases be reduced and the stable development of the securities industry guaranteed.

Conceptual Representation for Crisis-Related Tweet Classification

The importance of social media such as Twitter, as a conduit for actionable and tactical information during disasters is increasingly recognized. During crisis situations, rapid and effective response actions by emergency services are critical to assure the safety of the public. In this paper, we propose a conceptual representation for crisis-related tweet classification. In order to classify a stream of tweets related to the incident, the crisis-related terms in each tweet are represented as conceptual entities such as event entities, category indicator entities, information type entities, URL entities, and user entities. For tweet classification, we have compared support vector machines and deep learning model which combines class activation mapping with one-shot learning in convolutional neural networks. Experimental results on TREC 2018 Incident Streams test collection show significant improvement over the baseline system.

Fuel of the keeping needs of the energy discharge during nitrogen on the tribological characteristics of the design steel 45

The effect of power discharge category W in BATR on tribological characteristics of nitrous steel 45 is investigated in the work. The highest wear resistance of steel 45 corresponds to mode 7, which provides optimum physico-chemical characteristics of the nitrided layer.
 The ratio of the intensities of the passage of the main BATR subprocesses determines the structure and phase composition of the nitrided layers. Depending on the current combination of parameters of the mode of formation of the nitrided layer, the intensity of the flow of the above subprocesses (nitride formation, sputtering and diffusion saturation of the surface with nitrogen), and therefore the intensity of the formation of certain phases may be different, and sometimes reverse. For example, as the energy of the incident stream W increases, the pre-formed nitride layer is sprayed, which stimulates the process of nitrogen diffusion into the metal base and the formation of e and g - phases. When the flow energy is insufficient to atomize the nitride layer, it acts as a kind of barrier that impedes or completely stops the process of nitrogen diffusion.
 It is established that the decrease in the specific discharge power leads to a decrease in the thickness of the nitride and diffusion zones and, as a consequence, the tribological characteristics deteriorate. It is revealed that at the maximum values of energy parameters, a nitrous containing layer is formed e , g і a - phase. The decrease in voltage and current density causes the particle to increase g - pfase (Fe4N) and according to the reduction of the share e - phase (Fe2N). At minimum values of energy parameters of formation of nitrides on the surface is absent and the nitrided layer consists only of a - phase.

Waves of large amplitudes in geophysical and technical applications

The paper addresses the asymptotic models that explicitly describe the structure of solitary waves with recirculation zones for some special but important incident stream configurations, which occur in geophysical and industrial applications . The key feature that allows building a theoretical model is that shear and/or stratification of the media in geophysical applications or axisymmetric swirling incoming flows in technical applications have an almost linear equation for vorticity. It happens when the upstream flow is almost linearly stratified in the case of geophysical applications and a swirling flow has almost solid body rotation if industrial applications are considered. It is shown that the resulting equation for the stationary amplitude function of the solitary waves is described by a generalized Korteweg-de Vries equation in the outer zone, consistenty matched with a new complicated equation in the inner zone, which contains the recirculation core. This recirculation zone exists for wave amplitudes that are slightly greater than a certain critical amplitude, for which a wave breaking initially occurs. The recirculation zones have a universal structure, so that their width increases up to the semi-infinite bore as the amplitude of the wave increases from a critical amplitude to a certain maximum amplitude. This amplitude may be sensitive to the actual configuration of the incident flow. Regardless of the physical nature, solitary waves are described by two types of equations with different non-linearities. The type of nonlinearity in the inner zone where the vortex core is located is then caused by the position of the vortex core at the outer boundary or in the middle of the flow.

Numerical simulation of local scour around two pipelines in tandem using CFD–DEM method

In the field of offshore oil and gas engineering, the arrangement of multiple pipelines are becoming more common, the spacing between the pipelines and the incoming stream velocity will significantly affect the scouring process around the pipelines. In this study, the effect of space ratio (G/D) and the stream velocity on the scouring process around two pipelines in tandem are investigated using the coupled approach of computational fluid dynamics (CFD) and discrete element method (DEM). Here G is the spacing between the pipelines and D is the diameter of the pipeline. Specifically, the effect of space ratio and the stream velocity are discussed by simulating the gap ratio (G/D) between two pipelines ranging from 1 to 3 with an interval of 1, under the stream velocity U = 0.5,1 and 2 m/s, The results indicate that when G/D ≤ 2, the equilibrium scour depth below the upstream pipeline (S1) is slightly larger than that under the downstream pipeline (S2), S1 and S2 slightly increase as the gap ratio increases. Whereas for G/D > 2, the equilibrium scour depth beneath the upstream pipeline is slightly smaller than that under the downstream pipeline, S1 and S2 slightly decrease as the gap ratio increases. Furthermore, the scour depths are highly dependent on and positively related to the incoming stream velocity, the equilibrium bed profiles are similar under the same incident stream velocity with different gap ratios.

Published incidents and their proportions of human error

PurposeThis paper aims to provide an understanding of the proportions of incidents that relate to human error. The information security field experiences a continuous stream of information security incidents and breaches, which are publicised by the media, public bodies and regulators. Despite the need for information security practices being recognised and in existence for some time, the underlying general information security affecting tasks and causes of these incidents and breaches are not consistently understood, particularly with regard to human error.Design/methodology/approachThis paper analyses recent published incidents and breaches to establish the proportions of human error and where possible subsequently uses the HEART (human error assessment and reduction technique) human reliability analysis technique, which is established within the safety field.FindingsThis analysis provides an understanding of the proportions of incidents and breaches that relate to human error, as well as the common types of tasks that result in these incidents and breaches through adoption of methods applied within the safety field.Originality/valueThis research provides original contribution to knowledge through the analysis of recent public sector information security incidents and breaches to understand the proportions that relate to human error.

Turbulence structure and similarity in the separated flow above a low building in the atmospheric boundary layer

Separated and reattaching flows over sharp-leading-edge bluff bodies are important to investigate in order to improve our understanding of practical flows such as the case of low-rise buildings in the atmospheric boundary layer. In this study, Particle Image Velocimetry measurements of the separated-reattaching flows over the roof surface of a low-rise building model were taken for six different turbulent boundary layer conditions. The results were analyzed to understand how the incident turbulence affects the flow field of the separation bubbles above the low-rise building roof. The mean flow field above the roof-surface was found to be approximately similar across the six terrain conditions using the mean reattachment length in the streamwise direction and the maximum mean thickness of the separated shear layer in the vertical direction. However, the turbulence stresses are not similar which is attributed to high levels of initial turbulence kinetic energy in the separated shear layer. This leads to fundamental differences in the initial development of the separated flow when compared to flows with lower turbulence in the incident stream. The results indicate that the Kelvin-Helmholtz instability may be altered, or perhaps even suppressed, in the initial flow development region. This leads to substantially different turbulence statistics and characteristics within the separated shear layers.

Closed-loop control of a spatially developing free shear flow around a steady state

This paper provides preliminary results on the closed-loop control of a spatially developing mixing-layer induced by two parallel incident streams with different velocities. The goal of the control law was to stabilize the flow around a desired state (known to reduce mixing). The way to achieve this flow control consists of linearizing the Navier-Stokes equations about the desired state, spatially discretizing the resulting linear system and determining the feedback gain according to an optimal control law. Actuations were located in the input boundary of the system. State of the flow was assumed to be reconstructed from image sensors. The control law has been validated on a realistic non-linear system (Navier-Stokes solver). More precisely, these simulation results have shown that perturbations can be efficiently rejected.

Research methods of plasma stream interaction with heat-resistant materials

An experimental automated system was designed and constructed for studying the parameters and characteristics of non-stationary interacting system high-enthalpy-plasma stream-investigated sample: enthalpy of plasma in the incident stream; speed and temperature of plasma stream; temperature of electrons and heavy particles, ionic composition and their spatial distribution; heat flux incident on the sample (kW/cm2); surface temperature of the sample; ablation of the sample material, and others. Measurements of achievable plasma heat flux levels are carried out by calorimetry of plasma streams incident on the surface of multisection copper calorimeter. Determination of acceleration characteristics for profiled plasma torch nozzle, as well as the gas flow rate is produced by measuring the total pressure using the Pitot tube. Video visualization of interacting system is carried out using synchronized high-speed cameras. Micropyrometry of the selected zone on the sample surface is carried out by high-speed, three-wavelength pyrometer. To measure the rate of mass loss of the sample, in addition to the weighing method of evaluation the methods of laser knife and two-position stereoscopy are used. Plasma and sample emission characteristics are performed with two separate spectrometers.

Control of vortex shedding and drag reduction through dual splitter plates attached to a square cylinder

In this paper we have made a numerical study on the control of vortex shedding and drag reduction of a cylinder by attaching thin splitter plates. The wake structure of the cylinder of square cross-section with attached splitter plates is analyzed for a range of Reynolds number, based on the incident stream and height of the cylinder, in the laminar range. The Navier-Stokes equations governing the flow are solved by the control volume method over a staggered grid arrangement. We have used the semi-implicit method for pressure-linked equation (SIMPLE) algorithm for computation. Our results show that the presence of a splitter plate upstream of the cylinder reduces the drag, but it has a small impact on the vortex shedding frequency when the plate length is beyond 1.5 time the height of the cylinder. The presence of a downstream splitter plate dampens the vortex shedding frequency. The entrainment of fluid into the inner side of the separated shear layers is obstructed by the downstream splitter plate. Our results suggest that by attaching in-line splitter plates both upstream and downstream of the cylinder, the vortex shedding can be suppressed, as well as a reduction in drag be obtained. We made a parametric study to determine the optimal length of these splitter plates so as to achieve low drag and low vortex shedding frequency.

Research on Application of Listed Company Financial Fraud Distinguish Based on Acceleration-convergent BP network algorithm

Financial fraud has been a big problem in the field of financial accounting for a long time. An endless stream of financial fraud incidents was exposed. These cases on the one hand influenced the development of enterprise itself, the industry trend and on the other hand affected the development of the market. Many scholars have focuses on the issue from different angles and established some identification model of financial fraud. But these models generally do not have universal applicability because they are usually created in a specific environment or under accidental conditions. This paper improves the original method by accelerating the convergence of the excitation function of BP neural network algorithm. The sample of the article comes from 138 listed companies between 2010 and 2012. We respectively establish the financial reporting fraud identification models based on BP neural network algorithm and the improved algorithm. According to the comparison of results, we get that recognition accuracy of the improved algorithm reaches 93.48% and the forecasting effect is obviously better.

An Investigation into Air-Sand-Water Three-Phase Flow through the Sandblasting Nozzle

The numerical analysis of air-sand-water three-phase turbulent flow through converging-diverging nozzle is investigated for employing on sandblasting systems. For this purpose-dispersed flow of air-sand-water by various airs inlet pressures and different mass flow rates of sand particles and water droplets were considered. Two-way turbulence coupling between particles/droplets and airflow as well as interference between the incident streams of particles and rebounded from the wall were applied in the numerical model. In addition, the shock wave, which is produced in supersonic flow at diverging part of nozzle, was considered. In this study the Realizable k-ε and Discrete Phase models were utilized for simulating of multi-phase turbulent flow through the converging-diverging nozzle. As review of literature indicates there is not any experimental or analytical data on three-phase flow through the nozzle, consequently for validation of model, the same turbulent and multi-phase models were utilized on air-water two-phase flow. The obtained results were in good agreement with the experimental data. According to the results of three-phase flow simulation, the averaged exhaust momentum of sand particles had inverse proportion with water mass flow rate, and increasing of air inlet pressure had significant effect on mean exhaust velocity of sand particles.

Dependence of flow characteristics of rectangular cylinders near a wall on the incident velocity

Numerically simulated results are presented for a family of rectangular cylinders with aspect ratios r1 (=b/a with height a and width b) ranging from 0.1 to 1.0 (square cylinder) to gain a better insight into the dependency of the aerodynamic characteristics on the operational dimensionless parameters, namely Reynolds number Re and aspect ratio r1. This work describes the flow from a long cylinder of rectangular cross-section placed parallel to a wall and subjected to a uniform shear flow. The flow is investigated in the laminar Reynolds number range (based on the incident stream at the cylinder upstream face and the height of the cylinder) at cylinder to wall gap height 0.5 times the cylinder height. The governing unsteady Navier-Stokes equations are solved numerically through a finite volume method on a staggered grid system using QUICK scheme for con- vective terms. The resulting equations are then solved by an implicit, time-marching, pressure correction-based SIMPLE algorithm for Reynolds number up to 1,000. The critical Reynolds numbers at which vortex shedding from the cylinder is started are specified for both the cases: far from the wall and near to the wall. It is reported that the vortex shedding from the rectangular cylinder of lower aspect ratio r1(≤ 0.25) becomes regular and insensitive to the Reynolds number, while the aerodynamic characteristics of the rectangular cylinders with higher aspect ratio r1(≥ 0.5) are strongly dependent on the Reynolds number.

Calculation of resultant vector and principal moment of light pressure forces acting upon the spacecraft with a solar sail

Two methods of calculating the resultant vector and principal moment of light pressure forces, having an effect on a spacecraft with a composite solar sail, are compared. The first method is based on analytical formulas obtained without regard to shading of some parts of the sail by others. The second method uses a detailed geometrical model of the sail, which allows one to take such shading into account. Some part of photons falling on a sail is supposed to be reflected from it in a mirror manner, while the others are completely absorbed. The range of variation of sail orientation parameters with respect to incident solar light streams, where the first method turns out to be accurate enough, is found.

Financial services security changes with the times

Tense economic times and insider malfeasance have provided a steady stream of data breach incidents for firms both large and small. Stephen Pritchard examines what financial services providers are doing to protect their customers' money - and information - from prying eyes

Numerical simulation of an oscillating cylinder in a cross-flow at low Reynolds number: Forced and free oscillations

A numerical simulation of the flow past a circular cylinder which is able to oscillate transversely to the incident stream is presented in this paper for a fixed Reynolds number equal to 100. The 2D Navier–Stokes equations are solved by a finite volume method with an industrial CFD code in which a coupling procedure has been implemented in order to obtain the cylinder displacement. A preliminary work is first conducted for a fixed cylinder to check the wake characteristics for Reynolds numbers smaller than 150 in the laminar regime. The Strouhal frequency f S and the aerodynamic coefficients are thus controlled among other parameters. Simulations are then performed with forced oscillations characterized by the frequency ratio F = f 0/ f S, where f 0 is the forced oscillation frequency, and by the adimensional amplitude A. The wake characteristics are analyzed using the time series of the fluctuating aerodynamic coefficients and their power spectral densities (PSD). The frequency content is then linked to the shape of the phase portraits and to the vortex shedding mode. By choosing interesting couples ( A, F), different vortex shedding modes have been observed, which are similar to those of the Williamson–Roshko map. A second batch of simulations involving free vibrations (so-called vortex-induced vibrations or VIV) is finally carried out. Oscillations of the cylinder are now directly induced by the vortex shedding process in the wake and therefore, the time integration of the motion is realized by an explicit staggered algorithm which provides the cylinder displacement according to the aerodynamic charges exerted on the cylinder wall. Amplitude and frequency response of the cylinder are thus investigated over a wide range of reduced velocities to observe the different phenomena at stake. In particular, the vortex shedding modes have also been related to the frequency response observed and our results at Re = 100 show a very good agreement with other studies using different numerical approaches.

Vortex shedding in shear flow past tandem square cylinders in the vicinity of a plane wall

Abstract The flow of incompressible fluid past a pair of square cylinders in tandem placed close to a flat wall is studied in the presence of an incident linear velocity profile. The flow field is considered for a separation distance between the wall and the cylinders wall-side face at 0.5 times the height of the cylinder, at various values of spacing distance between the cylinders. The flow field is assumed to be laminar and two-dimensional for Reynolds number (based on the height of the cylinder D and the incident stream U at the centreline of the cylinders) up to 200. The governing unsteady Navier–Stokes equations are computed through a finite volume method over a staggered grid arrangement. A QUICK scheme is employed for the convective terms. The code has been tested for accuracy by comparing with the published results for certain values of the flow parameters. With the aid of vorticity contours, Strouhal number and velocity profiles, the interactions of the asymmetric separated shear layers emerging from either side of each cylinder and the wall boundary layer are studied for low to moderate values of inter-cylinder spacing distance. The effects on the force experienced by the cylinders is also considered in the present study. The flow field is found to be steady up to a certain critical Re. This critical value of Re depends on the spacing ratio of the cylinders. The plane wall encounters unsteady separation when cylinders exhibit vortex shedding. The flow characteristics for the present configuration is compared with the corresponding unbounded case and the case where a single cylinder exposed to shear flow in close proximity of a plane wall.

Analytical models of the interference between incident and rebounding particles within an abrasive jet: Comparison with computer simulation

Analytical models by Andrews and Horsfield and Anand et al. that describe interference between a non-diverging incident stream of spherical particles and those rebounding from a flat surface were modified to include a larger scope of stream variables, such as radial symmetry, stream density, and a more complex rebound geometry incorporating coefficients of restitution and friction. Expressions for the probability of collision at a radial distance from the stream centre, between an incident particle and a rebounding particle in the collision zone above the surface, were derived. Using this, expressions relating the percentage of particles reaching the surface without undergoing prior collisions to dimensionless stream parameters were derived, and compared to results obtained from a previously developed computer model. It was found that the results of the modified models compared well to those obtained using the computer simulation at oblique incidence, thus allowing an estimate of the critical flux below which a given level of particle interference is likely to occur to be conveniently determined.

Influence of Buoyancy on Vortex Shedding and Heat Transfer from a Square Cylinder in Proximity to a Wall

The flow and heat transfer past a heated cylinder of square cross section mounted horizontally above a plane wall and subjected to a uniform shear flow is considered. The flow field is considered for a moderate range of Reynolds number (based on the incident stream at the cylinder upstream face and the height of the cylinder) and Grashof number at cylinder-to-wall gap height 0.5 times the cylinder height. The flow field and heat transfer are computed through a pressure-correction-based iterative algorithm with the QUICK scheme in convective terms. The code is tested for accuracy by comparing with published results for certain values of the flow parameters. We examine the combined effects of buoyancy and shear flow on the vortex shedding behind the cylinder in close proximity to a plane wall. A boundary layer develops along the wall, and this interacts with the shear layer formed along the two sides of the cylinder. The role of the thermally induced baroclinic vorticity production term on the vortex shedding is examined. Our results show that the breakdown of vortex shedding takes place beyond certain values of Richardson number (which depends on the Reynolds number). The dependence of the average rate of heat transfer from the surface of the cylinder on Reynolds number and Grashof number is also investigated.