Evasive Maneuvers Research Articles

Snail Crossing by Corey R. Tabor

Reviewed by: Snail Crossing by Corey R. Tabor Natalie Berglind Tabor, Corey R. Snail Crossing; written and illus. by Corey R. Tabor. Balzer + Bray, 2020 [38p] Trade ed. ISBN 978-0-06-287800-7 $17.99 Reviewed from galleys R 3-6 yrs Snail sights a cabbage across the road and sets out at his fastest pace to reach it, though his journey won't come without obstacles. First, a car hurtles his way ("Some things are too big and fast for snails to ponder"); next, he disrupts a line of ants and subsequently shelters them in his shell from the rain; then, he fends off a hungry crow with evasive maneuvers (or perhaps a car that honks scares it off); and last, when he finally reaches the end of the road, he's found that he turned himself around and ended up where he started. The ants, grateful for the shelter, carry Snail some cabbage, and everyone's happy. This simple readaloud shows determined main character Snail fearlessly (and obliviously) facing down motor vehicles and predators to comical effect (a scene inside his shell where Snail is a sluggy lump offering tea to the ants under a Tiffany-style lamp is particularly hilarious). Tabor's watercolor and colored pencil illustrations render Snail an easily lovable figure with a pink, swirled shell and big, friendly eyes with occasionally determined eyebrows, and the art captures the scale of Snail against his looming surroundings. Use this along with Slater's charming Escargot (BCCB 3/17) for a snail-themed storytime or just to inspire viewers to take on a seemingly impossible task of their own. [End Page 189] Copyright © 2019 The Board of Trustees of the University of Illinois

Способ определения двух шаговых маневров расхождения с учетом МППСС-72

Способ определения двух шаговых маневров расхождения с учетом МППСС-72

On the relationship between non-optimum operations and fuel requirement for large civil transport aircraft, with reference to environmental impact and contrail avoidance strategy

ABSTRACTThe general problem of determining cruise fuel burn is addressed by considering the variation of the product of engine overall efficiency and airframe lift-to-drag ratio, (ηoL/D), with Mach number and lift coefficient. This quantity is the aerothermodynamic determinant of fuel burn rate. Using a small amount of real aircraft data and exploiting normalisation, it is found that near universal relationships exist between the key variables. With this major simplification, an analytic, near exact solution is derived in which the aircraft-related input data are reduced to just three parameters, namely the optimum value of (ηoL/D) and the lift coefficient and Mach number combination at which it occurs. These are quantities that are either available from open information sources or can be estimated using established analytic methods. By introducing models of the take-off and climb and the descent and landing phases, the method is extended to provide accurate trip fuel estimates.It is shown that there is an ideal flight level (IFL) at which the fuel consumption rate is a minimum for all speeds in the normal cruise operating range. Furthermore, the IFL at the end of cruise is approximately the same for all aircraft, whilst the IFL at the beginning of cruise depends, primarily, on the distance to be flown. There is little dependence on the size of the aircraft, or its take-off mass.In the context of the ‘fuel-based’ assessment of operational inefficiency, the method is further developed to determine the sensitivity of the trip fuel requirement to changes in the operational parameters governed by air traffic management (ATM). The result is two simple equations. These are used to estimate the current ATM fuel burden. At the global level, this is about 20% with more than half being attributable to flights of less than 1,200 km.Finally, the method is used to estimate the fuel burn penalty associated with reducing contrail formation by simply avoiding those regions of the atmosphere that are supersaturated with respect to ice. If the aircraft is at the IFL when avoiding action is required, flying below the supersaturated region minimises the additional fuel use. Even when multiple evasive manoeuvres are needed, the additional trip fuel requirement is expected to be less than 0.5%.

Conserved behavioral circuits govern high-speed decision-making in wild fish shoals

To evade their predators, animals must quickly detect potential threats, gauge risk, and mount a response. Putative neural circuits responsible for these tasks have been isolated in laboratory studies. However, it is unclear whether and how these circuits combine to generate the flexible, dynamic sequences of evasion behavior exhibited by wild, freely moving animals. Here, we report that evasion behavior of wild fish on a coral reef is generated through a sequence of well-defined decision rules that convert visual sensory input into behavioral actions. Using an automated system to present visual threat stimuli to fish in situ, we show that individuals initiate escape maneuvers in response to the perceived size and expansion rate of an oncoming threat using a decision rule that matches dynamics of known loom-sensitive neural circuits. After initiating an evasion maneuver, fish adjust their trajectories using a control rule based on visual feedback to steer away from the threat and toward shelter. These decision rules accurately describe evasion behavior of fish from phylogenetically distant families, illustrating the conserved nature of escape decision-making. Our results reveal how the flexible behavioral responses required for survival can emerge from relatively simple, conserved decision-making mechanisms.

Updates on Immunotherapy for the Treatment of Skin Cancer

Skin cancer is the most common malignancy in the USA, arising when mutated cells escape the host’s natural immune surveillance. Immunotherapy helps boost the host’s immune system, augmenting the antitumor response. Given the ability of the immune system to evolve with a tumor’s evasive maneuvers, it is not surprising that immunotherapy has demonstrated durable clinical benefit in patients with cancer, including certain types of skin cancers. Significant progress has been made with the recent development of immunotherapy for skin cancers. Here, we review the literature on immunotherapies used in the treatment of skin cancer, including immune checkpoint inhibitors, interferon, interleukin-2, BCG, talimogene laherparepvec, and imiquimod. Immune checkpoint inhibitors, which block CTLA-4 and PD-1 signaling pathways, have improved overall survival in patients with metastatic melanoma. The combination of nivolumab and ipilimumab has yielded higher overall survival rates than either agent alone, but at the price of higher rates of immune-related adverse events. In 2017, a PD-L1 inhibitor, avelumab, became the first FDA-approved treatment for patients with metastatic Merkel cell carcinoma. Since 2011, new immunotherapy treatments, including CTLA-4, PD-1, and PD-L1 inhibitors, have become the mainstay of treatment for many advanced skin cancers, supplanting chemotherapy for first-line treatment of metastatic melanoma and Merkel cell carcinoma.

A Ship Domain-Based Method of Determining Action Distances for Evasive Manoeuvres in Stand-On Situations

A ship encounter can be considered safe if neither of ships’ domains (defined areas around ships) is intruded by other ships. Published research on this includes optimising collision avoidance manoeuvres fulfilling domain-based safety conditions. However, until recently there was no method, using ship’s domain to determine exact moment when a particular collision avoidance manoeuvre can still be successfully performed. The authors have already proposed such method for give-way encounters. In the paper, documenting continuation of the research, another kind of scenarios is considered. This paper is focused on situations where the own ship is the stand-on one and the target is supposed to manoeuvre. The presented method uses a ship’s dynamics model to compute distance necessary for a manoeuvre successful in terms of avoiding domain violations. Additionally, stability-related phenomena and their impact on possible manoeuvres in heavy weather are taken into account. The method and applied models are illustrated in a series of simulation results. The simulations cover various examples of stand-on situations, including encounters in heavy weather conditions. Discussed manoeuvres may be limited to course alteration or may combine turns with speed reduction.

Situational influences on response time and maneuver choice: Development of time-critical scenarios

Findings concerning drivers’ response times to sudden events vary considerably across studies due to different experimental setups and situational characteristics, such as expectancy of an event and urgency to react. While response times are widely reported in the literature, understanding of drivers’ choice of maneuvers in time-critical situations is limited. Standardized test scenarios could enhance the comparability of studies and help in attaining a better understanding of driver behavior in these situations.In an effort to achieve these improvements, three driving simulator studies (N = 131) were conducted to investigate drivers’ response time and maneuver choice under a range of situational conditions. Each study took place in a specific environmental setting (urban, rural, and highway) and incorporated one unexpected and 12 subsequent events (increased expectancy). Four different time-critical scenarios were used to evoke different driver responses. In three scenarios, obstacles suddenly entered the roadway (braking, steering, or both possible). A fourth scenario comprised the sudden braking of a leading vehicle (only braking possible). Half of the drivers performed a cognitive secondary task. To validate the findings, results from an additional field test (N = 14) were compared to the results from the simulated urban environment.As expected, response choice was influenced by scenario characteristics (available braking distance and room for evasive maneuvers). Braking maneuvers were more frequent in settings with lower speed limits (urban) while steering maneuvers were found at higher speed limits (highway). Responses to suddenly appearing obstacles were fastest in the urban setting at 540–680 ms; these responses were 200–300 ms slower in the rural and highway settings. Response times increased by 100–200 ms when drivers responded to braking leading vehicles rather than obstacles. Braking responses were 200–350 ms slower and steering responses were 90–200 ms slower when drivers responded to an unexpected event rather than subsequent events. The cognitive secondary task had no significant effect. The simulated environment and the field test produced comparable response behavior.The current study provides reference numbers that help to establish a set of standardized test scenarios for future studies. On basis of this study, nine scenarios are recommended for the context of time-critical crash avoidance maneuvers. Such standardized test scenarios could improve the comparability of future studies on response time and maneuver choice.

Social Force as a Microscopic Simulation Model for Pedestrian Behavior in Crowd Evacuation

Understanding the evacuation mechanism has been important subject nowadays in order to model the simulation on the pedestrian behavior in crowd evacuation for the case study of fire emergency scenario in the building. Almost two decades the interest of Social Force Model (SFM) in pedestrian traffic increased significantly as a microscopic model to have a realistic simulation model. The social interactions between the pedestrian is emergent phenomena and very hard to capture, rare and evasive maneuvers in order to avoid collisions between the agents or so called as pedestrians. SFM has been chosen to simulate and modeling the case study based on the crowd dynamic, pedestrian dynamic and evacuation dynamic.

A Novel Penetration-evade Guidance Law against Two Homing Missiles

A novel guidance for an evader which is exposed to a threat of two homing missiles is presented. Each missile is assumed to measure solely its own line-of-sight (LOS) angle and share it with other missile. Such information sharing enables the missiles to form a triangular measuring baseline relative to the evader and to improve their estimation accuracy. However, if the separation angle between the two LOS is small enough, the observability of such double-LOS measuring approach becomes weak. Motived by this observation, the idea of the proposed concept is to bring the missile on the same LOS with target in the first stage. As for the second stage, the evader perform an appropriately timed maximum evasive maneuver. The simulation results demonstrate that the proposed guidance law can reduce the estimate and guidance accuracy of interceptors and achieve the goal of penetration.

1B1-3 Analysis of binaural signals of foreseeable sound facilitating traffic participant's evasive maneuver

1B1-3 Analysis of binaural signals of foreseeable sound facilitating traffic participant's evasive maneuver

Evasion maneuver for transseptal approach during cryoballoon pulmonary vein isolation

PurposePulmonary vein isolation (PVI) is a cornerstone therapy in patients with symptomatic atrial fibrillation. One current method is performing a PVI using a cryoballoon (CB). The CB is inserted into the left atrium via a steerable sheath. However, at times, passing of the interatrial septum by the sheath is hindered, e.g., due to septal fibrosis. Here we report our experience with an evasion maneuver to facilitate this approach using a 6F multipolar and steerable coronary Sinus catheter (CS) for predilatation of the interatrial septum. Methods and resultsWe report 10 patients undergoing a CB-PVI, where the investigator experienced difficulties in passing the interatrial septum with the CB sheath. In these cases, after three conventional abortive attempts, we predilated the transseptal puncture site using both the CS catheter and the dilatator of the CB sheath. Thereafter access of the CB sheath to the left atrium could be achieved instantly and without further resistance. ConclusionWe report a safe and feasible maneuver to facilitate transseptal access with the CB steerable sheath in cases complicated by excessive interatrial resistance.

Impact Angle Control Law with Sinusoidal Evasive Maneuver for Survivability Enhancement

In this paper, a new guidance law to enhance the survivability of anti-ship missiles against anti-air threats is presented. Sinusoidal maneuver acceleration is considered as a feed-forward input to a first-order lag system dynamics on the plane. Subject to this system dynamics a planar optimal guidance law for a stationary target is then derived to achieve zero miss distance and a specified impact angle while minimizing the control effort. By independent application of this planar law for homing guidance on the vertical and the horizontal plane, three-dimensional evasive guidance is easily synthesized. The phase difference as well as the magnitude and frequency of the sinusoidal acceleration inputs for the vertical and the horizontal guidance is the design parameter to shape the three-dimensional spiral or barrel-roll evasive maneuver pattern. Enhanced survivability with the proposed law against anti-air missiles is verified via numerical simulations.

RETRACTED ARTICLE: Fuzzy curvilinear path optimization using fuzzy regression analysis for mid vehicle collision detection and avoidance system analyzed on NGSIM I-80 dataset (real-road scenarios)

The majority of the prevailing collision detection and avoidance systems render evasive maneuvers for averting front and rear vehicle collisions. This paper introduces a mid vehicle collision detection and avoidance system with a constraint-free condition that produces mid vehicle maneuvers, particularly when jammed between the front and rear vehicles. Accordingly, three novel path estimation models based on crisp, fuzzy and fuzzy regression logic are blended to formulate a mid (host) vehicle collision detection and avoidance system. At the onset, the crisp model fits an offset-based curvilinear path for the mid vehicle to avoid edge collisions. The realized crisp model is later fuzzified to address more antecedents and accordingly deliver consequents for enhancing path estimation. Finally, the fuzzified model is regressed to obtain a good fitness for real-road conditions. The fused fuzzy regression renders an approximate version of the actual road strategy to obtain collision-free trajectories. This concept is later intrinsically extended to parallel parking in reverse direction. Simulation studies using coefficient of determination $$(R^{2} )$$ and mean square error on the field, real (next generation simulation-NGSIM) dataset reveals the goodness and the path closeness of the proposed system rendered by the novelly blended models tuned at each observation using the optimum h-uncertain factor. Also, relative mean square error analysis with state-of-art CDAS reveals the superiority of MCDAS, thereby making it amicable for real-road scenarios.

Spatial prediction of traffic accidents with critical driving events – Insights from a nationwide field study

Despite the fact that semi-autonomous vehicles will become more and more prevalent in the coming decades, recent studies have highlighted that traffic accidents will persist as a core issue for road users, insurers, and policy makers alike. Researchers and industry players see potential in the technology embedded in semi-autonomous vehicles to combat this challenge by reliably predicting locations with a high likelihood of traffic accidents. This technology can be leveraged to detect accidents and ‘near miss incidents’, such as heavy braking and evasive manoeuvres, otherwise known as Critical Driving Events (CDEs). The locations of CDEs could identify areas of high accident exposure, offering automotive insurers a unique opportunity to reduce traffic accidents through the adoption of active loss prevention business models, such as providing safe-routing services and in-vehicle warnings. To date, there is limited empirical evidence on whether the Crash Frequency and Crash Rate of locations can be accurately identified through CDEs. To address this research gap, an 18-week naturalistic driving field study of 72 vehicles was conducted in Switzerland, covering over 690,000 km. Data collected from the CAN Bus of these vehicles indicate that there is a proportional relationship between the CDEs of the fleet, and the Crash Frequency and Crash Rate of a location. Furthermore, a nationwide spatial regression analysis was applied to determine Crash Frequency across the majority of the Swiss road network. We identify the relationship between Crash Frequency, and the CDEs and Trip Frequency of the fleet, along with additional explanatory variables for urban and highway locations. These insights provide first evidence that insurance companies and other industry players with access to a nationwide semi-autonomous fleet can determine existing and emerging locations of high accident probability, enabling more proactive business models and safety focused services.

Drivers’ effective decelerating zone in an urban Vehicle-Pedestrian conflict situation: Observational studies and analyses

To analyse the drivers’ decelerating behavior in conflict avoidance process under Vehicle-Pedestrian conflict situation is accordingly a surrogate method for the guidance of driver evasive manoeuvre and improving the active driving safety. Field observation data has been collected by video recording and image processing at urban unsignalized midblock crosswalks in Beijng, China and Munich, Germany. The relationship between deceleration rate and vehicle speed has been statistically described. By analyzing how the time-related measures (Vehicle Time to Conflict Point and Pedestrian Time to Conflict Point) and the distance-related measures (Vehicle longitudinal distance to Conflict Point and Pedestrian Lateral distance to Conflict Point) affect the deceleration rate choice, the drivers‘ effective decelerating zone with sight angle has been proposed with the consideration of longitudinal & lateral conflict behavior. Minimum Vehicle-Pedestrian conflict distance is calculated and a 2 m minimum distance is suggested as the threshold for collision discrimination. Comparisons which address the needs to make the intercultural adaptation when introducing Driver Assistance Systems to developing countries have also been made to show the significant differences between China and Germany. The whole work could hopefully be the groundwork in the target of conflict pre-scanning by decelerating zones under various conflict situations and the design of vehicle active safety systems.

Cooperative Guidance Law for Target Pair to Lure Two Pursuers into Collision

A novel cooperative defensive guidance law is presented for a two-on-two engagement. Instead of classical strategies in which evasive maneuvers are performed or additional agents (e.g., defender missiles) are deployed, the target pair lures the pursuing missiles into collision. The optimal cooperative strategy is solved using state-dependent Riccati equation method. Linearized kinematics and arbitrary-order linear adversaries’ dynamics are assumed in the guidance law derivation. Imperfect information is assumed on the relative states and the guidance laws employed by the missile pair. Guidance strategies that the pursuing missiles may employ are assumed to belong to a finite set of linear guidance laws. In addition to the proposed cooperative defensive strategy, a decentralized estimation scheme based on the multiple-model adaptive estimation approach is also presented. Guidance law and estimation performance are demonstrated using nonlinear simulations. Simulation results show the viability of the proposed guidance law and highlight the sensitivity of the guidance law to range measurement accuracy.

Discrepancies in the spiking threshold and frequency sensitivity of nocturnal moths explainable by biases in the canonical auditory stimulation method.

The auditory stimulation method used in experiments on moth A cell(s) is generally believed to be adequate to characterize the encoding of bat echolocation signals. The stimulation method hosts, though, several biases. Their compounded effects can explain a range of discrepancies between the reported electrophysiological recordings and significantly alter the current interpretation. To test the hypothesis that the bias may significantly alter our current understanding of the moth's auditory transducer characteristics, papers using the same auditory stimulation method and reporting on either spiking threshold or spiking activity of the moth's A cells were analysed. The consistency of the reported data was assessed. A range of corrections issued from best practices and theoretical background were applied to the data in an attempt to re-interpret the data. We found that it is not possible to apply a posteriori corrections to all data and bias. However the corrected data indicate that the A cell's spiking may (i) be independent of the repetition rate, (ii) be maximum when detecting long and low-intensity pulses and (iii) steadily reduce as the bat closes on the moth. These observations raise the possibility that a fixed action pattern drives the moths' erratic evasive manoeuvres until the final moment. In-depth investigations of the potential bias also suggest that the auditory transducer's response may be constant for a larger frequency range than thought so far, and provide clues to explain the negative taxis in response to the searching bats' calls detection.

Injured probability assessment in frontal pedestrian-vehicle collision counting uncertainties in pedestrian movement

In probabilistic approaches, where uncertainties in pedestrian motion are counted, the distance model is important for the accurate and robust collision risks evaluation. Focusing on the typical frontal pedestrian-vehicle collision, the conflict distance model with the merit to distinguish front impacts from side ones is presented. Based on stochastic pedestrian model and Unscented Transformation (UT) method, the time-to-collision (TTC) and conflict distance are sampled, and their probability density functions (pdf) as well as the collision probability are deduced. The presented distance model and probabilistic method are verified with Monte Carlo (MC) as the reference, and show the high accuracy and potential for real-time application. Utilizing the estimated collision speed and its probability distribution, a unified model assessing the injured probabilities of pedestrian in front collision is proposed. A pedestrian-vehicle conflict scenario is constructed to evaluate the effectiveness of the probabilistic injury assessment. Simulation results show that the proposed method is sensitive to evasive maneuvers, and provides more useful cues for the optimization of collision avoidance control than the deterministic approaches.

Continued source level reduction during attack in the low‐amplitude bat Barbastella barbastellus prevents moth evasive flight

Abstract Ears evolved independently in many insect taxa due to the selection pressure of echolocating bats. Eared moths perform evasive flight manoeuvres upon hearing approaching bats, thereby substantially increasing survival probability. Accordingly, eared moths constitute only a minor portion of many bats’ diets. In contrast, the barbastelle bat Barbastella barbastellus almost exclusively feeds on eared moths by emitting low‐amplitude stealth echolocation calls that are undetectable by distant moths. While closing in on the prey, however, the calls might become audible. We thus hypothesised that barbastelle bats lower the source level of their calls even further while closing in, such that the level at the moth's ear remains below the moth's hearing threshold and the moth fails to elicit its evasive manoeuvre. We tested these hypotheses by offering tethered moths to barbastelle bats in the wild and in captivity. We reconstructed the bats’ three‐dimensional flight paths based on time‐of‐arrival differences of the echolocation calls at four microphones, measured the received sound levels at the moth's position with an additional miniature microphone, and calculated call source levels. We show that barbastelle bats continuously reduced source level upon detecting a moth, thereby delaying the time and shortening the distance when the moth might detect the bat. The received level at the targeted moth never exceeded the moth's neuronal hearing threshold by more than 10 dB, which is likely sufficiently low to prevent moth evasive flight. Barbastelle bats emit low‐amplitude calls to counter moth hearing. Continued amplitude reduction during an attack extends the time before the prey becomes aware of the predator, if at all. In combination, these two strategies allowed barbastelle bats to access a food resource which is largely unavailable to competing species, thereby probably altering competition between sympatric predators. A plain language summary is available for this article.

Model predictive cooperative localization control of multiple UAVs using potential function sensor constraints

The global localization of multiple mobile robots can be achieved cost efficiently by localizing one robot globally and the others in relation to it using local sensor data. However, the drawback of this cooperative localization is the requirement of continuous sensor information. Due to a limited sensor perception space, the tracking task to continuously maintain this sensor information is challenging. To address this problem, this contribution is presenting a model predictive control (MPC) approach for such cooperative localization scenarios. In particular, the present work shows a novel workflow to describe sensor limitations with the help of potential functions. In addition, a compact motion model for multi-rotor drones is introduced to achieve MPC real-time capability. The effectiveness of the presented approach is demonstrated in a numerical simulation, an experimental indoor scenario with two quadrotors as well as multiple indoor scenarios of a quadrotor obstacle evasion maneuver.