Driver Sensitivity Research Articles

Understanding no fault found event risk in military aircraft MRO planning: A step towards robust bidding and contract finalization

No fault found (NFF) is a reported fault for which the root cause cannot be found. An NFF event not only reduces the availability of the equipment to customers but also results in financial losses to the manufacturer. To date, risk due to NFF events is not considered separately in aircraft Maintenance, Repair, and Overhaul (MRO) planning. In this paper, we have studied the NFF event risk identification, distribution, and optimization in an aircraft MRO process based on data collected over three decades of aircraft maintenance. For framework development and formulating the critical NFF risk drivers, this paper applies soft system methodology with detailed semi-structured interviews of industry experts. For NFF risk distribution and optimization, we have used agent-based simulation modeling. The quantitative assessment of more than 5000 NFF cases in an aircraft MRO organization shows that NFF events are significantly non-deterministic during the life cycle of an aircraft. The three identified critical NFF risk drivers in the research are the MRO process stage, aircraft life cycle stage, and human working skills. The MRO process stage is the time of the NFF event during repair activity. The life cycle stage represents the timeline of the NFF event in useful aircraft life. Human working skill represents the role of manpower in the NFF event solution. Further theoretical elaborations of the research lead to the optimized NFF risk break-up at the contract preparation stage and risk driver's sensitivity analysis by the aircraft assembler, operator, and sub-contractor at the commercial bid submission stage.

A dynamical traffic flow model for a cognitive drivers' sensitivity in Lagrangian scope

A new microscopic traffic flow model is established based on heterogeneous driver's sensitivity; in this new model, the driver's sensitivity is defined as being dependent on the headway distances to the preceding vehicle, similar to Bando’s optimal velocity function. We introduce the formulation of this cognitive driver's sensitivity utilizing a modified form of Bando’s optimal velocity function. A simple methodology, which is used for improving Bando’s optimal velocity function, has been implemented for developing the cognitive driver’s sensitivity function, which establishes a correlation between the flow field’s density and human drivers' responses. The model is highly advanced for introducing a human-driven traffic flow field considering the driver’s mental behavioral activity. Using the linear stability condition, we elucidate a neutral stability condition. A series of numerical simulations indicates how the present model describes dynamics that differ from the conventional model, which assumes a constant driver's sensitivity.

A macroscopic traffic flow model that includes driver sensitivity to the number of free spaces ahead

This paper addresses the first-order extension of the Lighthill–Whitham– Richards (LWR) macroscopic traffic flow model. Although previous studies have focused on the fluid aspect of traffic flow, none have addressed the sensitivity of drivers to the number of free spaces within a certain distance ahead of the subject driver. To incorporate driver behavior, we used the number of free spaces ahead of subject drivers and their sensitivity to the number of free spaces within a certain distance ahead. The resulting model is a convection-diffusion model. By computing Einstein's diffusion equation and comparing it with the diffusion coefficient in the extended model, a theoretical relation for the driver's sensitivity was derived. A representation of the numerical results of the LWR model, the convection-diffusion model with a typical diffusion coefficient, and the extended model showed that the proposed model has a lower mean relative error value.

An extended car-following model based on visual angle and backward looking effect

By introducing driver's visual angle and backward looking effect into the full velocity difference model (FVDM), this paper proposes an extended car-following model. Through linear stability analysis and simulation analysis, the paper gets following conclusions: First of all, the neutral stability line of the extended model is asymmetry. Secondly, the stability of traffic flow is influenced by the width of the leading vehicle, the length of the following-car's head and the vertical distance from driver's eyes to vehicle's head. Thirdly, driver pay close attention to the rear vehicle can strengthen traffic flow, and driver's sensitivity of visual angle will influence the stability of traffic flow. Finally, the extended model can explain some complex nature of traffic phenomena and makes the car-following model more realistic.

F-3-3 色情報の閾下提示による注意誘導(F-3 メカニカルシステムとその知能化-人の視点を中心に,口頭発表:メカニカルシステムとその知能化)

This paper presents the new warning method to increase the driver's sensitivity for recognizing hazardous factors in the driving environment. By performing some experiments to five to six subjects, the response time for detecting the mark that is shown suddenly tends to be decreased when the colored subliminal marks are shown up in advance. Some experimental results tell us the black, white and blue subliminal marks are available for guiding an attention to certain object with the stable response behavior.

C-5 視覚情報の閾下提示による注意誘導(口頭発表:メカニカルシステムとその知能化)

This paper presents the new warning method to increase the driver's sensitivity for recognizing hazardous factors in the driving environment. By performing many experiments to 5 subjects, the response time for detecting the mark that is shown suddenly tends to be decreased when the subliminal marks are shown up in advance. Some experimental results tell us the subliminal mark with directional arrow is available for guiding an attention to certain object.

Phase transition on speed limit traffic with slope

Through introducing a generalized optimal speed function to consider spatial position, slope grade and variable safe headway, the effect of slope in a single-lane highway on the traffic flow is investigated with the extended optimal speed model. The theoretical analysis and simulation results show that the flux of the whole road with the upgrade (or downgrade) increases linearly with density, saturates at a critical density, then maintains this saturated value in a certain density range and finally decreases with density. The value of saturated flux is equal to the maximum flux of the upgrade (or downgrade) without considering the slight influence of the driver's sensitivity. And the fundamental diagrams also depend on sensitivity, slope grade and slope length. The spatiotemporal pattern gives the segregation of different traffic phases caused by the rarefaction wave and the shock wave under a certain initial vehicle number. A comparison between the upgrade and the downgrade indicates that the value of saturated flux of the downgrade is larger than that of the upgrade under the same condition. This result is in accordance with the real traffic.

Driver training conditions affect sensitivity to the impairing effects of alcohol on a simulated driving test.

Research shows that prior behavioral training in a challenging environment reduces alcohol-induced impairment on simple psychomotor tasks. However, no studies have examined if this relationship generalizes to driving performance. The present study examined simulated driving performance and tested the hypothesis that a challenging training history would protect against the impairing effects of alcohol on driving performance. The challenging training history involved driving in a visually-impoverished environment. Thirty adults were randomly assigned to one of three groups. Two groups were tested under alcohol (0.65 g/kg) after prior experience performing the task under either a visually-impoverished environment or a normal visual environment. The remaining group served as a control and was trained and tested under the visually-impoverished condition environment. Results showed that individuals trained in the impoverished environment displayed sober levels of performance when their performance was subsequently tested under alcohol. By contrast, volunteers trained in a normal environment showed impairment under alcohol. The findings suggest that differences in driving training history can affect a driver's sensitivity to the impairing effects of alcohol.

Analytical study on the criticality of the stochastic optimal velocity model

In recent works, we have proposed a stochastic cellular automaton model of traffic flow connecting two exactly solvable stochastic processes, i.e., the asymmetric simple exclusion process and the zero range process, with an additional parameter. It is also regarded as an extended version of the optimal velocity model, and moreover it shows particularly notable properties. In this paper, we report that when taking optimal velocity function to be a step function, all of the flux-density graph (i.e. the fundamental diagram) can be estimated. We first find that the fundamental diagram consists of two line segments resembling an inversed-λ form, and next identify their end-points from a microscopic behaviour of vehicles. It is notable that by using a microscopic parameter which indicates a driver's sensitivity to the traffic situation, we give an explicit formula for the critical point at which a traffic jam phase arises. We also compare these analytical results with those of the optimal velocity model, and point out the crucial differences between them.

3105 ステアリングの特性変動に対するドライバの弁別閾および適応動作特性に関する一考察(OS4-3 自動車を中心に(2),OS4 ヒューマンインタフェース,TRANSLOG 2006)

This study discussed driver's sensitivity and adaptability to variation of handling characteristics. Firstly, we constructed an experimental vehicle, which is installed steer-by-wire (SBW) system. In order to seize basic characteristic of driver adaptation to time variation of the steering gear ratio. The amount of correcting maneuver is, on the whole, increased with the steering gear ratio increases. And smoothness of the steering maneuver is decreased. There are some situations that the maneuver performance is recovered gradually by adaptive handling. And we focus on these situations, we conducted some experiments using desk top experimental device. The adaptation of handling was explained by experimental results.

비전 기반 스마트 와이퍼 시스템을 위한 지능형 레인 센싱 알고리즘 개발

A windshield wiper system plays a key part in assurance of driver's safety at rainfall. However, because quantity of rain and snow vary irregularly according to time and velocity of automotive, a driver changes speed and operation period of a wiper from time to time in order to secure enough visual field in the traditional windshield wiper system. Because a manual operation of wiper distracts driver's sensitivity and causes inadvertent driving, this is becoming direct cause of traffic accident. Therefore, this paper presents the basic architecture of vision-based smart wiper system and the rain sensing algorithm that regulate speed and interval of wiper automatically according to quantity of rain or snow. Also, this paper introduces the fuzzy wiper control algorithm based on human's expertise, and evaluates performance of suggested algorithm in the simulator model. Especially the vision sensor can measure wider area relatively than the optical rain sensor, hence, this grasps rainfall state more exactly in case disturbance occurs.

Artificial Sensitivity for Power Steering: The Proactive Safety Steering Control

Based on the nonlinear behaviour of the tires and of the hydraulic assistance, this paper proposes a new control strategy for electro-hydraulic power steering that amplifies the driver's sensitivity on the steering wheel when approaching dangerous situations. The Proactive Safety Steering Control gives wide safety margins that allows the driver to correct the car dynamics and to prevent dangerous actions before the car physical limit is really reached.

The Value of an Accelerator Release Signal

The value of a signal shown on the rear of an automobile when the accelerator is released was investigated by measuring (1) the magnitude of decelerations in coasting passenger cars, (2) the ability of drivers to detect coasting of a vehicle they are following, and (3) coasting periods used by a number of drivers on various trips. Coasting decelerations of a sample of passenger vehicles did not exceed 3 ft/sec 2. The driver's sensitivity (ΔH), the change in spacing necessary to detect coasting of a lead vehicle, was a direct function of the initial headway (H) with a median value ΔH = 0.12H. Instrumentation of a motor-pool automobile showed that most coasting durations were between 0.5 and 5 sec. with speed reductions of less than 4 mph. Release of the accelerator pedal was followed by braking on less than 50% of the coasting occasions. It was concluded that a coasting signal could not reliably indicate that braking would follow and was largely unnecessary for detection of coasting, but could aid in reducing the development of critical conditions when coasting periods exceed about 5 sec. A signal given only when coasting duration exceeds 5 sec. would not occur frequently and would provide valid information on most occasions.