Analysis of Automotive Cyber-Attacks on Highways using Partial Differential Equation Models

This is the author accepted manuscript.This paper considers scenarios wherein a group of malicious vehicles on a highway perform a cooperative attack with the motive of creating undesirable wave effects among other vehicles on the highway. The two species of vehicles - malicious vehicles and normal vehicles, and their associated interaction effects, are modeled using Partial Differential Equations (PDEs). The malicious vehicles, which may be arbitrarily distributed on the highway, perform a sequence of velocity changes with the objective of making the density/velocity profile on the highway, track a reference profile. This reference profile (chosen by the malicious vehicles) has the property that once generated, it spontaneously evolves into a shock wave that propagates along the highway. Analytical expressions governing the velocity inputs of the malicious vehicles with which they can generate such waves are determined, for perfect as well as imperfect information scenarios. Simulation results are presented to validate the theoryThe first two authors would like to acknowledge support from the National Science Foundation. This material is based upon work supported by the National Science Foundation under Grant IIS-1351677

Associations with photoreceptor thickness measures in the UK Biobank

Spectral-domain OCT (SD-OCT) provides high resolution images enabling identification of individual retinal layers. We included 32,923 participants aged 40–69 years old from UK Biobank. Questionnaires, physical examination, and eye examination including SD-OCT imaging were performed. SD OCT measured photoreceptor layer thickness includes photoreceptor layer thickness: inner nuclear layer-retinal pigment epithelium (INL-RPE) and the specific sublayers of the photoreceptor: inner nuclear layer-external limiting membrane (INL-ELM); external limiting membrane-inner segment outer segment (ELM-ISOS); and inner segment outer segment-retinal pigment epithelium (ISOS-RPE). In multivariate regression models, the total average INL-RPE was observed to be thinner in older aged, females, Black ethnicity, smokers, participants with higher systolic blood pressure, more negative refractive error, lower IOPcc and lower corneal hysteresis. The overall INL-ELM, ELM-ISOS and ISOS-RPE thickness was significantly associated with sex and race. Total average of INL-ELM thickness was additionally associated with age and refractive error, while ELM-ISOS was additionally associated with age, smoking status, SBP and refractive error; and ISOS-RPE was additionally associated with smoking status, IOPcc and corneal hysteresis. Hence, we found novel associations of ethnicity, smoking, systolic blood pressure, refraction, IOPcc and corneal hysteresis with photoreceptor thickness

Flow visualization and supersonic combustion studies of an acoustically open strut cavity

In this study, the supersonic flow over strut cavities was experimentally studied to understand flow features. Instantaneous schlieren imaging in non-reacting flow experiments exhibited the seven types of waves associated with cavity pressure oscillations and the formation of unstable shear layers on both sides. The shear layers moved in and out in synchronous and asynchronous modes at the trailing edge of the strut cavities. The symmetrical wave structure appeared on both sides in the synchronous mode, whereas the shear layers appeared in different stages of the cavity pressure oscillation cycle in the asynchronous mode, resulting in an asymmetrical wave structure. The pressure waves generated at the trailing edge of the strut cavities perturbed the shear layers during their movement toward the leading edge, creating a wavy shear layer with alternate troughs and crests. The pressure oscillations of the strut cavities had high-amplitude cavity modes with broadband noises, and their amplitude decreased from the trailing edge to the leading edge. The estimated recovery factor using the time lag between the signals of the leading and trailing edges showed that the flow inside the strut cavities was low subsonic. The measured dominant pressure oscillation modes had a closer match with the Rossiter modes. The pressure coefficient demonstrated that fluid accumulation inside the cavity increased with an increase in the aspect ratio. Furthermore, a higher fluid mass accumulated at the trailing edge than at the leading edge, and the difference in fluid accumulation increased with an increase in the aspect ratio. Supersonic combustion experiments with strut cavities showed that the strut cavity stabilized the flame. Moreover, the addition of an acoustically open strut cavity ahead of the flame-stabilizing cavity advanced the heat release location upstream

Analyzing the finite buffer batch arrival queue under Markovian service process: GI X /MSP/1/N

General independent arrival, Batch arrival, Finite buffer, Queue, Markovian service process, 60K25, 90B22,