40 research outputs found
Tyre model development using co-simulation technique for helicopter ground operation
This paper describes the development of a new aircraft tyre model applied using a co-simulation approach for the multibody dynamic simulation of helicopter ground vehicle dynamics. The new tyre model is presented using a point follower approach that makes a novel contribution to this area by uniquely combining elements of two existing tyre models used by the aircraft industry, namely the NASA R64 model developed by Smiley and Horne and the Engineering Sciences Data Unit (ESDU) Mitchell tyre model. Before the tyre model was used with a full helicopter model, a virtual tyre test rig was used to examine the tyre and to predict the tyre forces and moments for a range of tyre states. The paper concludes by describing the successful application of the new tyre model with a full helicopter model and the simulation of representative landing, take-off and runway taxiing manoeuvres. The predictive capability of the model is demonstrated to show the open-loop ground vehicle dynamics response of the helicopter and also the ground load predictive capability for the distribution of loads through the tyres, wheels and landing gears
Prediction and Topological Models in Neuroscience
In the last two decades, philosophy of neuroscience has predominantly focused on explanation. Indeed, it has been argued that mechanistic models are the standards of explanatory success in neuroscience over, among other things, topological models. However, explanatory power is only one virtue of a scientific model. Another is its predictive power. Unfortunately, the notion of prediction has received comparatively little attention in the philosophy of neuroscience, in part because predictions seem disconnected from interventions. In contrast, we argue that topological predictions can and do guide interventions in science, both inside and outside of neuroscience. Topological models allow researchers to predict many phenomena, including diseases, treatment outcomes, aging, and cognition, among others. Moreover, we argue that these predictions also offer strategies for useful interventions. Topology-based predictions play this role regardless of whether they do or can receive a mechanistic interpretation. We conclude by making a case for philosophers to focus on prediction in neuroscience in addition to explanation alone
Timescales of Multineuronal Activity Patterns Reflect Temporal Structure of Visual Stimuli
The investigation of distributed coding across multiple neurons in the cortex remains to this date a challenge. Our current understanding of collective encoding of information and the relevant timescales is still limited. Most results are restricted to disparate timescales, focused on either very fast, e.g., spike-synchrony, or slow timescales, e.g., firing rate. Here, we investigated systematically multineuronal activity patterns evolving on different timescales, spanning the whole range from spike-synchrony to mean firing rate. Using multi-electrode recordings from cat visual cortex, we show that cortical responses can be described as trajectories in a high-dimensional pattern space. Patterns evolve on a continuum of coexisting timescales that strongly relate to the temporal properties of stimuli. Timescales consistent with the time constants of neuronal membranes and fast synaptic transmission (5–20 ms) play a particularly salient role in encoding a large amount of stimulus-related information. Thus, to faithfully encode the properties of visual stimuli the brain engages multiple neurons into activity patterns evolving on multiple timescales
The virtual simulation of child sexual abuse: Online gameworld users’ views, understanding and responses to sexual ageplay.
This paper explores cultural understandings of virtual sexual ageplay in the online world of Second Life. Online sexual ageplay is the virtual simulation of child abuse by consensual adults operating in-world with child computer characters (avatars). Second Life is primarily governed by Community Standards which rely on residents (the users of Second Life) to recognise sexual ageplay and report it, which requires an appreciation of how residents view, understand and construct sexual ageplay. The research presented drew on 12 months of resident blog posts referring to sexual ageplay: 263 total, with 91 residents. The analysis of this talk explores the cultural understandings of this banned behaviour and beliefs about the nature of Second Life which underpin residents’ likelihood to report sexual ageplay and so comply with the Community Standards. In considering these issues the paper is able to highlight issues regarding the unique cultural position of abuse against children and key concerns which underpin the reporting behaviour of residents. Key considerations relate to defining online sexual activity, child avatars; the moral status of ‘reporters’, and sexual ageplay as a form of edgeplay; belief in the harmfulness of sexual ageplay and its relationship to real world behaviours
