Avoidance Performance Research Articles

The influence of in-vehicle speech warning timing on drivers’ collision avoidance performance at signalized intersections

Collision warning systems have been identified as an effective technique for avoiding accidents. In such a system, the delivery time of warning messages is a crucial factor that influences the success of collision avoidance. This study therefore contributes by providing experimental analyses on a range of delivery times of warning messages, which has been overlooked in past studies. Using simulator-based techniques, experimental scenarios are specifically designed for accounting the red-light-running events at intersections and drivers are recruited to test on different settings of warning timings. Several measures including brake reaction time, alarm-to-brake-onset time and deceleration are adopted as reflections of drivers’ performances under the collision avoidance process and they are connected to several factors by mixed effect models. According to the results, the collision warning system actually can largely reduce the occurrence of red-light-running collisions, more importantly it reveals the influence of warning timings within the predefined ranges and 4.0s or 4.5s may be a proper warning timing for the right-angle collisions accused by red-light-running vehicles in this study. Besides, effects from directional information embedded in warning messages are also investigated in this study. Findings are important to the design of collision warning systems especially in the aspect of warning timings.

Collision avoidance in TV white spaces: a cross-layer design approach for cognitive radio networks

One of the most promising applications of cognitive radio networks (CRNs) is the efficient exploitation of TV white spaces (TVWSs) for enhancing the performance of wireless networks. In this paper, we propose a cross-layer design (CLD) of carrier sense multiple access with collision avoidance (CSMA/CA) mechanism at the medium access control (MAC) layer with spectrum sensing (SpSe) at the physical layer, for identifying the occupancy status of TV bands. The proposed CLD relies on a Markov chain model with a state pair containing both the SpSe and the CSMA/CA from which we derive the collision probability and the achievable throughput. Analytical and simulation results are obtained for different collision avoidance and SpSe implementation scenarios by varying the contention window, back off stage and probability of detection. The obtained results depict the achievable throughput under different collision avoidance and SpSe implementation scenarios indicating thereby the performance of collision avoidance in TVWSs-based CRNs.

Virtual reality-based navigation task to reveal obstacle avoidance performance in individuals with visuospatial neglect.

Persons with post-stroke visuospatial neglect (VSN) often collide with moving obstacles while walking. It is not well understood whether the collisions occur as a result of attentional-perceptual deficits caused by VSN or due to post-stroke locomotor deficits. We assessed individuals with VSN on a seated, joystick-driven obstacle avoidance task, thus eliminating the influence of locomotion. Twelve participants with VSN were tested on obstacle detection and obstacle avoidance tasks in a virtual environment that included three obstacles approaching head-on or 30 (°) contralesionally/ipsilesionally. Our results indicate that in the detection task, the contralesional and head-on obstacles were detected at closer proximities compared to the ipsilesional obstacle. For the avoidance task collisions were observed only for the contralesional and head-on obstacle approaches. For the contralesional obstacle approach, participants initiated their avoidance strategies at smaller distances from the obstacle and maintained smaller minimum distances from the obstacles. The distance at detection showed a negative association with the distance at the onset of avoidance strategy for all three obstacle approaches. We conclusion the observation of collisions with contralesional and head-on obstacles, in the absence of locomotor burden, provides evidence that attentional-perceptual deficits due to VSN, independent of post-stroke locomotor deficits, alter obstacle avoidance abilities.

Tethered towing using open-loop input-shaping and discrete thrust levels

Abstract Asteroid retrieval, satellite servicing, and debris removal concepts often rely on a thrusting vehicle to redirect and steer a passive object. One effective way to tow the object is through a tether. This study employs a discretized tether model attached to six degree-of-freedom end bodies. To reduce the risk of a post-burn collision between the end bodies, discrete thrust input shaping profiles are considered including a Posicast input and a bang-off-bang thrust profile. These input shaping techniques attain desirable collision avoidance performance by inducing a tumbling or gravity gradient motion of the tethered formation. Their performance is compared to an earlier frequency notched thruster profile.

A Validation Study: Does Use of an Interactive Computer Based Laparoscopic Hysterectomy Trainer Expand Cognitive Surgical Knowledge of Ob/Gyn Trainees beyond That of Traditional Educational Tools?

To assesses improvement in cognitive knowledge of Ob/Gyn trainees following interactive computer-based instruction in pelvic anatomy, performance of laparoscopic hysterectomy and avoidance of surgical complications compared to traditional training.

Avoidance as expectancy in rats: sex and strain differences in acquisition.

Avoidance is a core feature of anxiety disorders and factors which increase avoidance expression or its resistance represent a source of vulnerability for anxiety disorders. Outbred female Sprague Dawley (SD) rats and inbred male and female Wistar-Kyoto (WKY) rats expressing behaviorally inhibited (BI) temperament learn avoidance faster than male SD rats. The training protocol used in these studies had a longstanding interpretive flaw: a lever-press had two outcomes, termination of the warning signal (WS) and prevention of foot shock. To disambiguate between these two explanations, we conducted an experiment in which: (a) a lever-press terminated the WS and prevented shock, and (b) a lever-press only prevented shock, but did not influence the duration of the WS. Thus, a 2 × 2 × 2 (Strain × Sex × Training) design was employed to assess the degree to which the response contingency of the WS termination influenced acquisition. Male and female SD and WKY rats were matched on acoustic startle reactivity within strain and sex and randomly assigned to the training procedures. In addition, we assessed whether the degree of avoidance acquisition affected estrus cycling in female rats. Consistent with earlier work, avoidance performance of female rats was generally superior to males and WKY rats were superior to SD rats. Moreover, female SD and male WKY rats were roughly equivalent. Female sex and BI temperament were confirmed as vulnerability factors in faster acquisition of avoidance behavior. Avoidance acquisition disrupted estrus cycling with female WKY rats recovering faster than female SD rats. Although termination of the WS appears to be reinforcing, male and female WKY rats still achieved a high degree (greater than 80% asymptotic performance) of avoidance in the absence of the WS termination contingency. Such disambiguation will facilitate determination of the neurobiological basis for avoidance learning and its extinction.

A novel rat model of Alzheimer’s disease based on lentiviral-mediated expression of mutant APP

BackgroundAlzheimer’s disease (AD) is characterized by progressive and irreversible cognitive and memory impairment. The discovery of familial forms of AD (fAD) in association with specific gene mutations facilitated the generation of numerous rodent models. These models in turn proved valuable for the study of molecular mechanisms underlying AD pathogenesis, and facilitated translational research and preclinical drug development. This study aimed to introduce a new rat model of AD simulating some aspects of the sporadic cases of disease. MethodsLentiviruses (LV) encoding human amyloid protein precursor (APP) bearing the fAD-linked Swedish and Indiana mutations (APPSw/Ind) were injected bilaterally in the hippocampus of adult rats. Passive avoidance and spatial memory performance were assessed 30 and 45days post-injection, respectively. APP overexpression, intracellular accumulation of β-amyloid (Aβ) peptide, and astrogliosis were also evaluated using immunohistochemical procedures. ResultsPassive avoidance memory deficit was followed by impairments in spatial memory retrieval in LV (APPSw/Ind)-injected rats, compared to control animals. In addition, LV expression of APPSw/Ind was associated with intraneuronal accumulation of Aβ, and reactive astrocytosis, two major AD hallmarks. ConclusionResults from this work suggest that LV-mediated delivery of APPSw/Ind in adult rats represents a cost and time-effective animal model for the study of mechanisms underlying APP-linked fAD pathogenesis. The relevance of this animal model to the study of sporadic AD is discussed.

P.1.h.031 Dopamine is involved in the different copulatory patterns of Roman high and low avoidance rats: studies with apomorphine and haloperidol

The cholinergic and dopaminergic innervation of the amygdala plays an important role in attention, emotional arousal, aversive forms of associative learning, conditioned responses, and stress responsivity. Roman High- (RHA) and Low-Avoidance (RLA) rats are an ideal model to study the potential impact of this innervation on behavioral responses, because they were selected bidirectionally for differences in their two-way active avoidance performance. RHA rats are known to quickly acquire two-way active avoidance and show indications of enhanced impulsive behavior, novelty seeking, and vulnerability to substance abuse, whereas RLA rats exhibit a passive coping style with high levels of immobility and enhanced stress responsivity. In the present study, the density of acetylcholine esterase (AchE)-positive cholinergic fibers and tyrosine hydroxylase immunoreactive (TH-ir) fibers were analyzed in various amygdala nuclei. In comparison to RLA rats, RHA rats displayed a significantly higher density of AchE-positive fibers in the lateral nucleus (La), the major sensory input area of the amygdala. In contrast, RLA rats showed a higher density of TH-ir fibers in the lateral division of the central nucleus (CeL), which modulates amygdala output and is known to contain more corticotropin-releasing hormone (CRH) positive neurons in RLA than in RHA rats. The findings suggest that a higher density of AchE-positive fibers in the La of RHA rats may facilitate attentional mechanisms and aversive forms of associative learning in RHA rats, whereas the increased density of TH-ir fibers in the CeL of RLA rats may be involved in the regulation of enhanced CRH expression and stress responsivity.

The Role of Goal Orientations in Explaining Academic Cheating in Students With Learning Disabilities: An Application of the Cusp Catastrophe

The purpose of the present study was to predict and explain the academic cheating behaviors of elementary school students with learning disabilities (LD) by applying the cusp catastrophe model. Participants were 32 students with identified LD from state governmental agencies although all both them and the typical students participated in the experimental manipulation (N = 480). Academic cheating was assessed using an empirical paradigm where true achievement was subtracted from achievement in a test without proper invigilation. Data analysis supported the proposed cusp catastrophe models, where mastery-related motives acted as asymmetry and performance goals as bifurcation variables respectively. These findings were confirmed with application of the interactive goal hypothesis (Barron & Harackiewicz, 2001), where the interactive approach and avoidance performance goal term functioned as a splitting factor in the relationship between adaptive motivation and performance.

Вплив агоніста та антагоніста α4β2 субодиниць Н-холінорецепторів на відтворення умовного рефлексу самиць щурів у різні фази естрального циклу

The present work was devoted to the comparative analysis of alpha4beta2 nicotinic acetylcholine receptors (nAChRs) in learning/ memory processes during ovary cycle assessed in adult female rats. RJR-2403 (1.0 mg/kg, i.p.), alpha4beta2 nAChRs agonist and mecamylamine (1.0 mg/kg, i.p.), alpha4beta2 nAChRs antagonist were injected chronically during 14 days. The processes of learning/memory were assessed in different models of learning: passive avoidance performance and Morris water maze. Chronic RJR-2403 administration to female rats improved the passive avoidance performance in proestrous and estrous as compared to the control animals. Also, RJR-2403 restored spatial learning during proestrous phases in Morris water maze, and stimulated the dynamics of spatial learning during estrous phases. On the contrary, chronic mecamylamine administration impaired non-spatial, and especially, spatial learning in females during key phases of ovary cycle. The results of the study suggest positive effect of alpha4beta2 nAChRs stimulation in learning/ memory processes during ovary cycle in the adult female rats.

Error model estimation for airborne beacon‐based surveillance

A next-generation aircraft collision avoidance system under development is designed to reduce unnecessary alerts while reducing the risk of mid-air collision. Current and future collision avoidance systems rely upon range, bearing and altitude information from airborne, beacon-based surveillance. Realistic models of surveillance error characteristics are needed in order to develop and certify the safety and performance of these systems. Prior models of bearing measurements assumed uncorrelated Gaussian noise. This study explains how hidden Markov models can be used to capture the time-correlated error characteristics exhibited by recorded surveillance data. Simulations show the impact of this higher-fidelity model on predicted collision avoidance performance.

The effects of achievement goal orientations and safety climate on safe and unsafe behavior

The purpose of this study is to test the effect of achievement goal orientations and safety climate on safe and unsafe behaviors. Safe behaviors were measured by observances and automatic safe behaviors, and unsafe behaviors by violations and mistakes. Three fifty employees from corporations were participated in this research. Both mastery approach goal and performance approach goal orientations have significant positive relations with the safe behaviors and negative relations with the unsafe behaviors, but both mastery avoidance goal and performance avoidance goal orientations have significant negative relations with the safe behaviors and positive relations with the unsafe behaviors. This results suggest to confirm the multiple goal perspective of the achievement goal orientation argued both mastery goal and performance goal orientations have relations with adaptive and maladaptive behaviors. Safety climates measured by five factors, management values, safety practice, safety training, safety communication, and supervisor leadership, were significant positive relations with safe behaviors and negative relations with unsafe behaviors. Specially safety climates have significantly stronger correlations with unintentional behaviors(automatic safe behavior and mistake) than intentional behaviors(observance and violation). The relative contributions of individual variables and organizational variables to safe and unsafe behaviors were discussed.

The effects of achievement goal orientations and safety climate on safe and unsafe behavior

The purpose of this study is to test the effect of achievement goal orientations and safety climate on safe and unsafe behaviors. Safe behaviors were measured by observances and automatic safe behaviors, and unsafe behaviors by violations and mistakes. Three fifty employees from corporations were participated in this research. Both mastery approach goal and performance approach goal orientations have significant positive relations with the safe behaviors and negative relations with the unsafe behaviors, but both mastery avoidance goal and performance avoidance goal orientations have significant negative relations with the safe behaviors and positive relations with the unsafe behaviors. This results suggest to confirm the multiple goal perspective of the achievement goal orientation argued both mastery goal and performance goal orientations have relations with adaptive and maladaptive behaviors. Safety climates measured by five factors, management values, safety practice, safety training, safety communication, and supervisor leadership, were significant positive relations with safe behaviors and negative relations with unsafe behaviors. Specially safety climates have significantly stronger correlations with unintentional behaviors(automatic safe behavior and mistake) than intentional behaviors(observance and violation). The relative contributions of individual variables and organizational variables to safe and unsafe behaviors were discussed.

Role of Dopamine D2 Receptors in Human Reinforcement Learning

Influential neurocomputational models emphasize dopamine (DA) as an electrophysiological and neurochemical correlate of reinforcement learning. However, evidence of a specific causal role of DA receptors in learning has been less forthcoming, especially in humans. Here we combine, in a between-subjects design, administration of a high dose of the selective DA D2/3-receptor antagonist sulpiride with genetic analysis of the DA D2 receptor in a behavioral study of reinforcement learning in a sample of 78 healthy male volunteers. In contrast to predictions of prevailing models emphasizing DA's pivotal role in learning via prediction errors, we found that sulpiride did not disrupt learning, but rather induced profound impairments in choice performance. The disruption was selective for stimuli indicating reward, whereas loss avoidance performance was unaffected. Effects were driven by volunteers with higher serum levels of the drug, and in those with genetically determined lower density of striatal DA D2 receptors. This is the clearest demonstration to date for a causal modulatory role of the DA D2 receptor in choice performance that might be distinct from learning. Our findings challenge current reward prediction error models of reinforcement learning, and suggest that classical animal models emphasizing a role of postsynaptic DA D2 receptors in motivational aspects of reinforcement learning may apply to humans as well.

A meta-analysis of self-reported achievement goals and nonself-report performance across three achievement domains (work, sports, and education).

During the past three decades, the achievement goal approach to achievement motivation has emerged as an influential area of research, and is dedicated to understanding the reasons behind the individual’s drive to achieve competence and performance. However, the current literature on achievement goals is segmented rather than integrated. That is, citations across the three major and distinct achievement domains (work, education, and sports) are more the exception than the rule and similarities and differences between findings for the different achievement domains have yet to be tested. The purpose of the present study was to examine the relationships between self-reported achievement goals and nonself-report performance through meta-analysis, and the moderating potential of achievement domain. Identifying achievement domain as moderator improves our understanding to which contexts we can (not) generalize conclusions to, it helps to understand seemingly inconsistent findings, and opens avenues for future research on the underlying processes. Because the achievement goal (AG) measure used in a study is partially confounded with achievement domain, we examined the moderating role of this variable as well. Our findings suggest that – overall – approach goals (either mastery or performance) were associated positively with performance attainment, whereas avoidance goals (either mastery or performance) were associated negatively with performance attainment. These relationships were moderated by achievement domain. For example, relative to the education or work domain, in the sports domain, we did not observe negative correlations between avoidance goals and performance. The absence of statistical moderation due to AG measure suggests that the observed moderation of achievement domain cannot be explained by the AG measure utilized. We suggest further steps to integrate the achievement goal literature, and accordingly, to broaden and deepen understanding of performance attainment in competence-relevant settings, including the workplace, the sports field, and the classroom.

Sorption of isoflavones to river sediment and model sorbents and outcomes for larval fish exposed to contaminated sediment

Isoflavones are compounds whose presence in the aquatic environment is increasingly recognized and may be of concern due to their potential to act as endocrine disruptors. Sorption to particles may be a relevant removal mechanism for isoflavones. This work investigated the influence of pH, ionic strength, and sediment composition on sorption of genistein and daidzein, two key isoflavones, using sorption isotherms and edges. The effect of sorbed isoflavones on the survival, growth, and predator avoidance performance of larval fathead minnows (Pimephales promelas) was assessed. Sorption to goethite and kaolinite was pH-dependent, with a maximum near pH 7 for both compounds. Sorption to montmorillonite was ionic-strength dependent but largely pH-independent. Overall, sorption to sediments is likely to sequester less than 5% of isoflavones in a discharge. No statistically significant effects were observed for larvae exposed to sorbed isoflavones, suggesting that sorption to sediments reduces exposure to isoflavones.

Rapid growth increases intrinsic predation risk in genetically modified Cyprinus carpio: implications for environmental risk

The intrinsic effect of feeding regime on survival and predation-induced mortality was experimentally tested in genetically modified (GM) Cyprinus carpio and wild specimens. The results clearly indicate a knock-on effect of the GH gene (gcGH) introduction into the C. carpio genome on their vulnerability to predation. The experiments unequivocally showed that it is the genetic nature of the C. carpio rather than its size that affects the risk of predation. In addition, fed C. carpio were more susceptible to predation risk. Thus, the study characterizes the existence of a trade-off between somatic growth and predator avoidance performance. Current research in Europe suggests that high uncertainty surrounding the potential environmental effects of escapee transgenic fishes into the wild is largely due to uncertainty in how the modified gene will be expressed. Understanding variables such as the cost of rapid growth on antipredator success would prove to be pivotal in setting up sound risk assessments for GM fishes and in fully assessing the environmental risk associated with GM fish escapees.

EFFICIENT DISTRIBUTED DETECTION OF NODE REPLICATION ATTACKS IN MOBILE SENSOR NETWORKS

Wireless Sensor Network (WSN) technology uses many nodes in a network for transformation of data. Detecting and monitor of the node is very difficult in distributed network and form a node replication attacks in a mobile sensor network .To detect the node replication attacks in mobile sensor networks using two localized algorithms, XED and EDD. Our proposed algorithm can resist node replication attacks in a localized fashion. Note that, the Nodes only need to do a distributed algorithm, task without the intervention of the base station. The techniques developed in our solutions are to challenge and response and encounter number, are fundamentally different from the others. Moreover, while most of the existing schemes in static networks rely on the witness finding strategy is cannot be applied to mobile sensor networks, the velocity exceeding strategy used in existing schemes in mobile networks incurs efficiency and more no security problems. Therefore, based on our node replication challenge and response to encounter number approaches in localized algorithms are proposed to resist node replication attacks in mobile sensor networks. The advantage of our proposed algorithm include 1) Localized detection; 2) Efficiency and effectiveness; 3) Network-wide synchronization avoidance; 4) Networkwide revocation avoidance Performance comparisons with known methods are provided to demonstrate the efficiency of our proposed algorithms.

Appearance- and competition-focused performance goals

We examined the utility of distinguishing between appearance- and competition-focused approach and avoidance performance goals to our understanding of motivation in physical education. Four achievement goals were tested composed of approach–avoidance and appearance–competition components. Three hundred and two pupils, aged 11–14 years, completed measures of appearance–competition approach–avoidance goals at the start of a football or gymnastics unit of work in physical education. Teacher-rated effort and National Curriculum attainment levels were recorded at the end of the unit of work as markers of performance in physical education. Confirmatory factor analysis supported the delineation of four goals in terms of the approach–avoidance and appearance–competition elements. Regression analyses subsequently revealed differences in the predictive utility of the four goals to performance in physical education. Thus, our understanding of motivational processes in physical education may be enhanced by utilising a more differentiated conception of normative achievement goals.

Panic disorder and exercise avoidance

1) To identify whether patients with panic disorder in general and those with the respiratory subtype in particular actively avoid exercise; 2) to investigate physiological differences in cardiopulmonary function parameters in patients with panic disorder in general, patients with the respiratory subtype of panic disorder, and healthy controls upon exercise challenge. Patients with panic disorder were classified as having either the respiratory or the non-respiratory subtype. Both groups were compared to controls in terms of exercise avoidance patterns and performance on cardiopulmonary exercise testing. Patients with panic disorder exhibited higher exercise avoidance scores and worse performance on cardiopulmonary exercise testing as compared with controls. No differences were found between patients with the respiratory and non-respiratory subtypes. Exercise avoidance is present in panic disorder and is associated with poorer performance on cardiopulmonary exercise testing. These findings are not limited to patients with the respiratory subtype of the disorder.