Computer simulation of a pilot in V/STOL aircraft control loops

The objective was to develop a computerized adaptive pilot model for the computer model of the research aircraft, the Harrier II AV-8B V/STOL with special emphasis on propulsion control. In fact, two versions of the adaptive pilot are given. The first, simply called the Adaptive Control Model (ACM) of a pilot includes a parameter estimation algorithm for the parameters of the aircraft and an adaption scheme based on the root locus of the poles of the pilot controlled aircraft. The second, called the Optimal Control Model of the pilot (OCM), includes an adaption algorithm and an optimal control algorithm. These computer simulations were developed as a part of the ongoing research program in pilot model simulation supported by NASA Lewis from April 1, 1985 to August 30, 1986 under NASA Grant NAG 3-606 and from September 1, 1986 through November 30, 1988 under NASA Grant NAG 3-729. Once installed, these pilot models permitted the computer simulation of the pilot model to close all of the control loops normally closed by a pilot actually manipulating the control variables. The current version of this has permitted a baseline comparison of various qualitative and quantitative performance indices for propulsion control, the control loops and the work load on the pilot. Actual data for an aircraft flown by a human pilot furnished by NASA was compared to the outputs furnished by the computerized pilot and found to be favorable

Computer simulation of a single pilot flying a modern high-performance helicopter

Presented is a computer simulation of a human response pilot model able to execute operational flight maneuvers and vehicle stabilization of a modern high-performance helicopter. Low-order, single-variable, human response mechanisms, integrated to form a multivariable pilot structure, provide a comprehensive operational control over the vehicle. Evaluations of the integrated pilot were performed by direct insertion into a nonlinear, total-force simulation environment provided by NASA Lewis. Comparisons between the integrated pilot structure and single-variable pilot mechanisms are presented. Static and dynamically alterable configurations of the pilot structure are introduced to simulate pilot activities during vehicle maneuvers. These configurations, in conjunction with higher level, decision-making processes, are considered for use where guidance and navigational procedures, operational mode transfers, and resource sharing are required

Computer simulation of multiple pilots flying a modern high performance helicopter

A computer simulation of a human response pilot mechanism within the flight control loop of a high-performance modern helicopter is presented. A human response mechanism, implemented by a low order, linear transfer function, is used in a decoupled single variable configuration that exploits the dominant vehicle characteristics by associating cockpit controls and instrumentation with specific vehicle dynamics. Low order helicopter models obtained from evaluations of the time and frequency domain responses of a nonlinear simulation model, provided by NASA Lewis Research Center, are presented and considered in the discussion of the pilot development. Pilot responses and reactions to test maneuvers are presented and discussed. Higher level implementation, using the pilot mechanisms, are discussed and considered for their use in a comprehensive control structure

A problem solving approach to visceral learning

Abstract only. Permission to include in repository granted by Sally Byers, Permissions Assistant, Wiley-Blackwell Publishing Ltd.An earlier paper in this series depicted visceral learning as a problem in concept identification in which subjects seek information about the visceral target (Roberts, Williams, Farrell, & Marlin. 1979). Concepts pertaining to this target are based initially upon procedural details of training and are modified as feedback identifies instances of the desired response. Evidence for this view was sought by examining verbal reports for the information about target responding that is presumably the product of a concept identification process. Accurate self-report was observed when subjects were successfully trained to produce either: 1) an increase and decrease in heart rate, or 2) lateralized changes (L > R and R> L) in skin conductance. Control of the response in the absence of accurate self-report was not observed in either training condition. The present paper describes an extended framework for the study of learning mechanisms. In this approach, a task statement is assumed to establish a problem space within which visceral learning proceeds. Major components of this space include: 1) a representation of task objectives. 2) initial concepts concerning effective strategies derived from the task statement and the subject's personal history, and 3) a processing system which is organized to acquire information about the response from feedback events. The processing system is seen as a construction which is determined uniquely for each learning procedure by processing requirements that are implicit in problem structure. The system organizes memory to receive information about the response and codes this information in a manner appropriate for production of the target in accordance with performance requirements of the task. This analysis suggested that within-subject training for two visceral targets with a transfer requirement (as in Roberts et al., 1979) might have favored identification of differences rather than similarities between the targets and encoding in a manner appropriate for recall without feedback as a retrieval cue. Consequently accurate self-report was assessed as a function of forewarning of transfer when subjects were trained to produce a single target alone. The purpose was to determine whether a problem-solving approach might identify processing conditions that favor veridical self-report following training on a feedback task. (Supported by A0132 from NSERC of Canada)Ye

Visceral learning as concept identification

Abstract only. Permission to include in repository granted by Sally Byers, Permissions Assistant, Wiley-Blackwell Publishing Ltd.Visceral learning may be depicted as a process in which subjects seek information about the behavioral goal. Concepts of this goal are based initially upon procedural details of training and are modified as feedback identifies instances of the target response. This approach was assessed by determining whether subjects were capable of describing activities associated with the visceral target after feedback training. Two groups were given visual feedback for changes in heart rate (HR) or lateralized skin conductance (LSC). The two visceral targets within each group (HR: inc/dec; LSC: L>R/R>L) were designated as Response A and Response B. Production of the response on A and B trials in the presence (Training) and absence (Transfer) of feedback was measured. After a one-hour session subjects were asked, without prior notification, to provide written reports describing what they did to control feedback on A and B trials. Awareness of the response was assessed by determining whether judges given the reports successfully identified the visceral target which was required on A and B trials for each subject. Awareness of activities related to feedback was also assessed by quantitative scales completed by the subjects after the written report. Awareness of the response was demonstrated on identification tasks for each experimental condition (HR and LSC). Furthermore, awareness (measured as probability ofcorrect identification) was significantly correlated with performance during Training and Transfer in the HR oroup, but this relationship was obtained only for Transfer in the LSC condition. Transfer without awareness was not observed in either group. Scale ratings did not differ between the visceral targets in either training condition. However, awareness was confirmed by significant correlations between these ratings and visceral performance for Training and Transfer in the HR group and for Transfer in the LSC group. These findings suggest that veridical concepts of the behavioral goal are formed during visceral learning. The concept-formation process appears important to Transfer but does not fully explain performance on feedback trials in the LSC experiment. (Supported by A0132 from NSERC of Canada)Ye

Effects of air pollution and the introduction of the London Low Emission Zone on the prevalence of respiratory and allergic symptoms in schoolchildren in East London: a sequential cross-sectional study

The adverse effects of traffic-related air pollution on children’s respiratory health have been widely reported, but few studies have evaluated the impact of traffic-control policies designed to reduce urban air pollution. We assessed associations between traffic-related air pollutants and respiratory/allergic symptoms amongst 8–9 year-old schoolchildren living within the London Low Emission Zone (LEZ). Information on respiratory/allergic symptoms was obtained using a parent-completed questionnaire and linked to modelled annual air pollutant concentrations based on the residential address of each child, using a multivariable mixed effects logistic regression analysis. Exposure to traffic-related air pollutants was associated with current rhinitis: NOx (OR 1.01, 95% CI 1.00–1.02), NO2 (1.03, 1.00–1.06), PM10 (1.16, 1.04–1.28) and PM2.5 (1.38, 1.08–1.78), all per μg/m3 of pollutant, but not with other respiratory/allergic symptoms. The LEZ did not reduce ambient air pollution levels, or affect the prevalence of respiratory/allergic symptoms over the period studied. These data confirm the previous association between traffic-related air pollutant exposures and symptoms of current rhinitis. Importantly, the London LEZ has not significantly improved air quality within the city, or the respiratory health of the resident population in its first three years of operation. This highlights the need for more robust measures to reduce traffic emissions

Priming by Chemokines Restricts Lateral Mobility of the Adhesion Receptor LFA-1 and Restores Adhesion to ICAM-1 Nano-Aggregates on Human Mature Dendritic Cells

LFA-1 is a leukocyte specific β2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs) may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into the lymph nodes, by transiently switching its molecular conformational state. However, the role of LFA-1 mobility in this process is not yet known, despite that the importance of lateral organization and dynamics for LFA-1-mediated adhesion regulation is broadly recognized. Using single particle tracking approaches we here show that LFA-1 exhibits higher mobility on resting mDCs compared to monocytes. Lymphoid chemokine CCL21 stimulation of the LFA-1 high affinity state on mDCs, led to a significant reduction of mobility and an increase on the fraction of stationary receptors, consistent with re-activation of the receptor. Addition of soluble monomeric ICAM-1 in the presence of CCL21 did not alter the diffusion profile of LFA-1 while soluble ICAM-1 nano-aggregates in the presence of CCL21 further reduced LFA-1 mobility and readily bound to the receptor. Overall, our results emphasize the importance of LFA-1 lateral mobility across the membrane on the regulation of integrin activation and its function as adhesion receptor. Importantly, our data show that chemokines alone are not sufficient to trigger the high affinity state of the integrin based on the strict definition that affinity refers to the adhesion capacity of a single receptor to its ligand in solution. Instead our data indicate that nanoclustering of the receptor, induced by multi-ligand binding, is required to maintain stable cell adhesion once LFA-1 high affinity state is transiently triggered by inside-out signals.Peer ReviewedPostprint (published version