The Estimation of Helicopter Pilot Workload Using Inverse Simulation. Internal Report No. 9624

In the first instance this report describes the means by which inverse simulation can be used as a pilot workload estimation tool. An alternative approach to defining the mathematical model of the ADS-33 Rapid Side-step Mission Task Element (MTE) is presented and is used to drive various inverse simulation runs. Studies are conducted into three varying aggression side-step MTEs and the comparison of two dissimilar helicopter configurations based on the Westland Lynx, simulated using the same side-step. It is shown how the resulting time-histories and quickness charts can be utilised in pilot workload and handling qualities estimation. A third quickness parameter associated with the lateral cyclic stick displacements required to fly the side-step MTEs is introduced and is shown to be capable of discriminating between the pilot workload required for each side-step and vehicle configuration. The latter study in the report presents the preliminary findings on the effects of workload by firstly, introducing a Stability and Control Augmentation System and secondly investigating the effects of altering the value of the lateral cyclic actuator time constant

The Estimation of Helicopter Pilot Workload Using Inverse Simulation: Longitudinal Manoeuvre Analysis. Internal Report No. 9625

In the preceding report the concept of estimating pilot workload using inverse simulation was introduced. The report examined the ADS-33C defined Rapid Side-step Mission Task Element (MTE), and illustrated how various quickness parameters could be obtained from the lateral cyclic pitch and stick displacement time histories. These quickness parameters were plotted on charts and it was shown how the resulting plots could be used to discriminate between two dissimilar helicopter configurations, or identify which manoeuvres were more aggressive and would probably lead to a higher level of workload being placed upon the pilot. The intention of this report is to provide a supplementary study to the previous one by analysing another linear repositioning manoeuvre, the Rapid Acceleration / Deceleration or Quick-hop MTE. The longitudinal cyclic channel will be investigated in terms of pitch and stick displacement and the equivalent quickness parameters calculated and plotted on charts. A final study mirroring the previous one, on control system influence by the introduction of a Stability and Control Augmentation System, (SCAS) and the alteration of the longitudinal cyclic actuator constant will also be carried out

The Estimation of Precision Pilot Model Parameters Using Inverse Simulation. Internal Report No. 9706

The practice of using mathematical models to simulate pilot behaviour in one-axis stabilisation tasks is a well known conventional simulation problem. In this report a system is developed whereby a mathematical model of a pilot is used as the controller of a rudimentary helicopter model. The main differences between this and other similar scenarios that have been found in the literature are that firstly, inverse simulation is used to provide results that are used as the forcing functions in the model of the pilot/helicopter system, and secondly a constrained optimisation routine is utilised to obtain values for the parameters within the pilot model itself. It will be shown that as the pilot is required to fly different manoeuvres, defined by standards set by the United States Army, or indeed if the severity of the set manoeuvres is varied, the pilot is required to adjust certain human parameters to fly the manoeuvre in a superlative manner. The report considers initially the pilot and helicopter models and subsequently analyses the system as a whole, illustrating how the pilot model can change depending on the circumstances

The Estimation of Helicopter Pilot Workload Using Inverse Simulation. Internal Report No. 9624

In the first instance this report describes the means by which inverse simulation can be used as a pilot workload estimation tool. An alternative approach to defining the mathematical model of the ADS-33 Rapid Side-step Mission Task Element (MTE) is presented and is used to drive various inverse simulation runs. Studies are conducted into three varying aggression side-step MTEs and the comparison of two dissimilar helicopter configurations based on the Westland Lynx, simulated using the same side-step. It is shown how the resulting time-histories and quickness charts can be utilised in pilot workload and handling qualities estimation. A third quickness parameter associated with the lateral cyclic stick displacements required to fly the side-step MTEs is introduced and is shown to be capable of discriminating between the pilot workload required for each side-step and vehicle configuration. The latter study in the report presents the preliminary findings on the effects of workload by firstly, introducing a Stability and Control Augmentation System and secondly investigating the effects of altering the value of the lateral cyclic actuator time constant

Mathematical Models of Three Slalom Types for Inverse Simulation. Internal Report No. 9716

In the absence of adequate data from flight trials, a request was put forward for the development of mathematical models of various configurations of slalom manoeuvres. The models were to be based on the existing manoeuvres as flown by United States Army, specified in ADS-33D, the Defence Evaluation and Research Agency (DERA), Bedford and the German Aerospace Research Establishment (DLR), the definitions of which have been stated previously by the DERA. This report describes the development of the manoeuvres and their utilisation within the inverse simulation package HELINV, at Glasgow University. It will be shown that data acquired from the inverse simulations of these manoeuvres can be used in workload calculations using software developed by Glasgow Caledonian University, and this process in itself will verify or disprove the validity of the manoeuvres that have been developed. Although there is potentially no real substitute for genuine data obtained from actual flight trials, it is hoped that these slalom simulations will prove to be a useful tool when used in conjunction with the inverse simulation, workload estimation metrics and handling qualities software

On the Development of Multiple Manoeuvre Mission Sequences for Inverse Simulation. Internal Report No. 9802

As part of the continuing programme of work and collaboration between the Defence Evaluation and Research Agency (DERA) and Glasgow University (GU), the author was invited to attend the final phase of flight simulation trials entitled ‘TWINS’ at DERA, Bedford; using the Advanced Flight Simulator (AFS) large motion system. The precise nature and details of the five-day trial are given in [1] but the main thrust of the trial was essentially divided into two areas: 1. The simulation of American Design Standard (ADS) Mission Task Elements (MTEs) using a software image database of Coltishall airfield with the appropriate ADS-33 visual cues. 2. The simulation of a mission sequence based on the Haxton Down software image database which comprised fourteen individual tasks. The tasks were either based on ADS MTEs or Nap-of-the-earth (NOE) flight. A full description of the manoeuvre elements is given in Appendix A of [1]. The inverse simulation package HELINV at GU contains a library of manoeuvres based both on ADS MTEs and NOE flight. However, the manoeuvres are separate and individual and until recently it was not possible to run a simulation of combinations of two or more manoeuvres. A request was put forward to develop a method whereby it was possible to choose several elements (MTE or NOE) from the manoeuvre menu and piece them together to form what has been termed a ‘mini-mission sequence’ and then inverse simulate the mission as a whole. This report describes that development and presents the results from several simulated mission runs

TRAIL-induced variation of cell signaling states provides nonheritable resistance to apoptosis.

TNFα-related apoptosis-inducing ligand (TRAIL), specifically initiates programmed cell death, but often fails to eradicate all cells, making it an ineffective therapy for cancer. This fractional killing is linked to cellular variation that bulk assays cannot capture. Here, we quantify the diversity in cellular signaling responses to TRAIL, linking it to apoptotic frequency across numerous cell systems with single-cell mass cytometry (CyTOF). Although all cells respond to TRAIL, a variable fraction persists without apoptotic progression. This cell-specific behavior is nonheritable where both the TRAIL-induced signaling responses and frequency of apoptotic resistance remain unaffected by prior exposure. The diversity of signaling states upon exposure is correlated to TRAIL resistance. Concomitantly, constricting the variation in signaling response with kinase inhibitors proportionally decreases TRAIL resistance. Simultaneously, TRAIL-induced de novo translation in resistant cells, when blocked by cycloheximide, abrogated all TRAIL resistance. This work highlights how cell signaling diversity, and subsequent translation response, relates to nonheritable fractional escape from TRAIL-induced apoptosis. This refined view of TRAIL resistance provides new avenues to study death ligands in general