The RL Perceptron: Generalisation Dynamics of Policy Learning in High Dimensions

Reinforcement learning (RL) algorithms have proven transformative in a range of domains. To tackle real-world domains, these systems often use neural networks to learn policies directly from pixels or other high-dimensional sensory input. By contrast, much theory of RL has focused on discrete state spaces or worst-case analysis, and fundamental questions remain about the dynamics of policy learning in high-dimensional settings. Here, we propose a solvable high-dimensional model of RL that can capture a variety of learning protocols, and derive its typical dynamics as a set of closed-form ordinary differential equations (ODEs). We derive optimal schedules for the learning rates and task difficulty - analogous to annealing schemes and curricula during training in RL - and show that the model exhibits rich behaviour, including delayed learning under sparse rewards; a variety of learning regimes depending on reward baselines; and a speed-accuracy trade-off driven by reward stringency. Experiments on variants of the Procgen game "Bossfight" and Arcade Learning Environment game "Pong" also show such a speed-accuracy trade-off in practice. Together, these results take a step towards closing the gap between theory and practice in high-dimensional RL.Comment: 10 pages, 6 figures, Preprin

A retrospective analysis of the definitive management of open talus fractures at a major trauma centre, comparing ORIF to FUSION: cohort study and audit of BOAST 4 guidelines.

PURPOSE: Open talus fractures are notoriously difficult to manage, and they are commonly associated with a high level of complications including non-union, avascular necrosis and infection. Currently, the management of such injuries is based upon BOAST 4 guidelines although there is no suggested definitive management, and thus, definitive management is based upon surgeon preference. The key principles of open talus fracture management which do not vary between surgeons are early debridement, orthoplastic wound care, anatomic reduction and definitive fixation whenever possible. However, there is much debate over whether the talus should be preserved or removed after open talus fracture/dislocation and proceeded to tibiocalcaneal fusion. METHODS: A review of electronic hospital records for open talus fractures from 2014 to 2021 returned fourteen patients with fifteen open talus fractures. Seven cases were initially managed with ORIF, and five cases were definitively managed with FUSION, while the others were managed with alternative methods. We collected patient's age, gender, surgical complications, surgical risk factors and post-treatment functional ability and pain and compliance with BOAST guidelines. The average follow-up of the cohort was 4 years and one month. EQ-5D-5L and FAAM-ADL/Sports score was used as a patient reported outcome measure. Data were analysed using the software PRISM. RESULTS: Comparison between FUSION and ORIF groups showed no statistically significant difference in EQ-5D-5L score (P = 0.13), FAAM-ADL (P = 0.20), FAAM-Sport (P = 0.34), infection rate (P = 0.55), surgical times (P = 0.91) and time to weight bearing (P = 0.39), despite a higher proportion of polytrauma and Hawkins III and IV fractures in the FUSION group. CONCLUSION: FUSION is typically used as second line to ORIF or failed ORIF. However, there is a lack of studies that directly compared outcome in open talus fracture patients definitively managed with FUSION or ORIF. Our results demonstrate for the first time that FUSION may not be inferior to ORIF in terms of patient functional outcome, infection rate and quality of life, in the management of patients with open talus fracture patients. Of note, as open talus fractures have increased risks of complications such as osteonecrosis and non-union, FUSION should be considered as a viable option to mitigate these potential complications in these patients

Rehabilitation versus surgical reconstruction for non-acute anterior cruciate ligament injury (ACL SNNAP): a pragmatic randomised controlled trial

BackgroundAnterior cruciate ligament (ACL) rupture is a common debilitating injury that can cause instability of the knee. We aimed to investigate the best management strategy between reconstructive surgery and non-surgical treatment for patients with a non-acute ACL injury and persistent symptoms of instability.MethodsWe did a pragmatic, multicentre, superiority, randomised controlled trial in 29 secondary care National Health Service orthopaedic units in the UK. Patients with symptomatic knee problems (instability) consistent with an ACL injury were eligible. We excluded patients with meniscal pathology with characteristics that indicate immediate surgery. Patients were randomly assigned (1:1) by computer to either surgery (reconstruction) or rehabilitation (physiotherapy but with subsequent reconstruction permitted if instability persisted after treatment), stratified by site and baseline Knee Injury and Osteoarthritis Outcome Score—4 domain version (KOOS4). This management design represented normal practice. The primary outcome was KOOS4 at 18 months after randomisation. The principal analyses were intention-to-treat based, with KOOS4 results analysed using linear regression. This trial is registered with ISRCTN, ISRCTN10110685, and ClinicalTrials.gov, NCT02980367.FindingsBetween Feb 1, 2017, and April 12, 2020, we recruited 316 patients. 156 (49%) participants were randomly assigned to the surgical reconstruction group and 160 (51%) to the rehabilitation group. Mean KOOS4 at 18 months was 73·0 (SD 18·3) in the surgical group and 64·6 (21·6) in the rehabilitation group. The adjusted mean difference was 7·9 (95% CI 2·5–13·2; p=0·0053) in favour of surgical management. 65 (41%) of 160 patients allocated to rehabilitation underwent subsequent surgery according to protocol within 18 months. 43 (28%) of 156 patients allocated to surgery did not receive their allocated treatment. We found no differences between groups in the proportion of intervention-related complications.InterpretationSurgical reconstruction as a management strategy for patients with non-acute ACL injury with persistent symptoms of instability was clinically superior and more cost-effective in comparison with rehabilitation management

RunARcade: A gamified exploration to encourage physical activity through the lens of AR smart glass interface

Over the past years, people’s traditional lifestyles have changed as a result of post-pandemic working from home habits and the advancements in technology becoming more accessible and faster. A growing number of medical studies have documented a rise in health issues observed in developed countries mostly due to sedentary lifestyles leading to physical inactivity. These health issues include, obesity and its associated disorders, such as diabetes and various types of cardiovascular diseases. As a result, considerable research efforts have been dedicated to exploring different strategies for encouraging people to engage in regular physical activity. Utilizing interactive visual perception and more complex sensory simulation, wearable technology blends gamification, entertainment and information to provide rich and instructive workout experience. Motivational learning can act as a primary catalyst for learning satisfaction which in turn engages users’ enthusiasm, develops personal interest and triggers attention. Wearable technology that offers helpful insights and progress tracking information during the regular practice and competition is changing sports like running and supports it in improving runners’ performance, motivation, and focus. As running is so widely practiced: wearables can motivate athletes and offer visually appealing and informative feedback during and after their runs. The objective of this creative scholarship is to examine the potential of integrating gamified augmented reality as a layer within the field of view (fov) of runners and brainstorm information architecture as the blueprint of all the functions of the running application and create a prototype video of the game prototype and images of the running experience without having to make a fully functional running game. This exploration also seeks to understand the challenges that might be faced by users wearing head-mounted display smart glasses while in motion, with constantly changing backgrounds. The creative component also explores the role of typography along with interactive 3D game objects and diverse gamification elements, with the goal of envisioning an enhanced and engaging gamified running experience

RunARcade: A gamified exploration to encourage physical activity through the lens of AR smart glass interface

Over the past years, people’s traditional lifestyles have changed as a result of post-pandemic working from home habits and the advancements in technology becoming more accessible and faster. A growing number of medical studies have documented a rise in health issues observed in developed countries mostly due to sedentary lifestyles leading to physical inactivity. These health issues include, obesity and its associated disorders, such as diabetes and various types of cardiovascular diseases. As a result, considerable research efforts have been dedicated to exploring different strategies for encouraging people to engage in regular physical activity. Utilizing interactive visual perception and more complex sensory simulation, wearable technology blends gamification, entertainment and information to provide rich and instructive workout experience. Motivational learning can act as a primary catalyst for learning satisfaction which in turn engages users’ enthusiasm, develops personal interest and triggers attention. Wearable technology that offers helpful insights and progress tracking information during the regular practice and competition is changing sports like running and supports it in improving runners’ performance, motivation, and focus. As running is so widely practiced: wearables can motivate athletes and offer visually appealing and informative feedback during and after their runs. The objective of this creative scholarship is to examine the potential of integrating gamified augmented reality as a layer within the field of view (fov) of runners and brainstorm information architecture as the blueprint of all the functions of the running application and create a prototype video of the game prototype and images of the running experience without having to make a fully functional running game. This exploration also seeks to understand the challenges that might be faced by users wearing head-mounted display smart glasses while in motion, with constantly changing backgrounds. The creative component also explores the role of typography along with interactive 3D game objects and diverse gamification elements, with the goal of envisioning an enhanced and engaging gamified running experience

RunARcade: A gamified exploration to encourage physical activity through the lens of AR smart glass interface

Over the past years, people’s traditional lifestyles have changed as a result of post-pandemic working from home habits and the advancements in technology becoming more accessible and faster. A growing number of medical studies have documented a rise in health issues observed in developed countries mostly due to sedentary lifestyles leading to physical inactivity. These health issues include, obesity and its associated disorders, such as diabetes and various types of cardiovascular diseases. As a result, considerable research efforts have been dedicated to exploring different strategies for encouraging people to engage in regular physical activity. Utilizing interactive visual perception and more complex sensory simulation, wearable technology blends gamification, entertainment and information to provide rich and instructive workout experience. Motivational learning can act as a primary catalyst for learning satisfaction which in turn engages users’ enthusiasm, develops personal interest and triggers attention. Wearable technology that offers helpful insights and progress tracking information during the regular practice and competition is changing sports like running and supports it in improving runners’ performance, motivation, and focus. As running is so widely practiced: wearables can motivate athletes and offer visually appealing and informative feedback during and after their runs. The objective of this creative scholarship is to examine the potential of integrating gamified augmented reality as a layer within the field of view (fov) of runners and brainstorm information architecture as the blueprint of all the functions of the running application and create a prototype video of the game prototype and images of the running experience without having to make a fully functional running game. This exploration also seeks to understand the challenges that might be faced by users wearing head-mounted display smart glasses while in motion, with constantly changing backgrounds. The creative component also explores the role of typography along with interactive 3D game objects and diverse gamification elements, with the goal of envisioning an enhanced and engaging gamified running experience

RunARcade: A gamified exploration to encourage physical activity through the lens of AR smart glass interface

Over the past years, people’s traditional lifestyles have changed as a result of post-pandemic working from home habits and the advancements in technology becoming more accessible and faster. A growing number of medical studies have documented a rise in health issues observed in developed countries mostly due to sedentary lifestyles leading to physical inactivity. These health issues include, obesity and its associated disorders, such as diabetes and various types of cardiovascular diseases. As a result, considerable research efforts have been dedicated to exploring different strategies for encouraging people to engage in regular physical activity. Utilizing interactive visual perception and more complex sensory simulation, wearable technology blends gamification, entertainment and information to provide rich and instructive workout experience. Motivational learning can act as a primary catalyst for learning satisfaction which in turn engages users’ enthusiasm, develops personal interest and triggers attention. Wearable technology that offers helpful insights and progress tracking information during the regular practice and competition is changing sports like running and supports it in improving runners’ performance, motivation, and focus. As running is so widely practiced: wearables can motivate athletes and offer visually appealing and informative feedback during and after their runs. The objective of this creative scholarship is to examine the potential of integrating gamified augmented reality as a layer within the field of view (fov) of runners and brainstorm information architecture as the blueprint of all the functions of the running application and create a prototype video of the game prototype and images of the running experience without having to make a fully functional running game. This exploration also seeks to understand the challenges that might be faced by users wearing head-mounted display smart glasses while in motion, with constantly changing backgrounds. The creative component also explores the role of typography along with interactive 3D game objects and diverse gamification elements, with the goal of envisioning an enhanced and engaging gamified running experience

RunARcade: A gamified exploration to encourage physical activity through the lens of AR smart glass interface

Over the past years, people’s traditional lifestyles have changed as a result of post-pandemic working from home habits and the advancements in technology becoming more accessible and faster. A growing number of medical studies have documented a rise in health issues observed in developed countries mostly due to sedentary lifestyles leading to physical inactivity. These health issues include, obesity and its associated disorders, such as diabetes and various types of cardiovascular diseases. As a result, considerable research efforts have been dedicated to exploring different strategies for encouraging people to engage in regular physical activity. Utilizing interactive visual perception and more complex sensory simulation, wearable technology blends gamification, entertainment and information to provide rich and instructive workout experience. Motivational learning can act as a primary catalyst for learning satisfaction which in turn engages users’ enthusiasm, develops personal interest and triggers attention. Wearable technology that offers helpful insights and progress tracking information during the regular practice and competition is changing sports like running and supports it in improving runners’ performance, motivation, and focus. As running is so widely practiced: wearables can motivate athletes and offer visually appealing and informative feedback during and after their runs. The objective of this creative scholarship is to examine the potential of integrating gamified augmented reality as a layer within the field of view (fov) of runners and brainstorm information architecture as the blueprint of all the functions of the running application and create a prototype video of the game prototype and images of the running experience without having to make a fully functional running game. This exploration also seeks to understand the challenges that might be faced by users wearing head-mounted display smart glasses while in motion, with constantly changing backgrounds. The creative component also explores the role of typography along with interactive 3D game objects and diverse gamification elements, with the goal of envisioning an enhanced and engaging gamified running experience

RunARcade: A gamified exploration to encourage physical activity through the lens of AR smart glass interface

Over the past years, people’s traditional lifestyles have changed as a result of post-pandemic working from home habits and the advancements in technology becoming more accessible and faster. A growing number of medical studies have documented a rise in health issues observed in developed countries mostly due to sedentary lifestyles leading to physical inactivity. These health issues include, obesity and its associated disorders, such as diabetes and various types of cardiovascular diseases. As a result, considerable research efforts have been dedicated to exploring different strategies for encouraging people to engage in regular physical activity. Utilizing interactive visual perception and more complex sensory simulation, wearable technology blends gamification, entertainment and information to provide rich and instructive workout experience. Motivational learning can act as a primary catalyst for learning satisfaction which in turn engages users’ enthusiasm, develops personal interest and triggers attention. Wearable technology that offers helpful insights and progress tracking information during the regular practice and competition is changing sports like running and supports it in improving runners’ performance, motivation, and focus. As running is so widely practiced: wearables can motivate athletes and offer visually appealing and informative feedback during and after their runs. The objective of this creative scholarship is to examine the potential of integrating gamified augmented reality as a layer within the field of view (fov) of runners and brainstorm information architecture as the blueprint of all the functions of the running application and create a prototype video of the game prototype and images of the running experience without having to make a fully functional running game. This exploration also seeks to understand the challenges that might be faced by users wearing head-mounted display smart glasses while in motion, with constantly changing backgrounds. The creative component also explores the role of typography along with interactive 3D game objects and diverse gamification elements, with the goal of envisioning an enhanced and engaging gamified running experience