942 research outputs found
An Intelligent Autopilot System that learns piloting skills from human pilots by imitation
An Intelligent Autopilot System (IAS) that can learn piloting skills by observing and imitating expert human pilots is proposed. IAS is a potential solution to the current problem of Automatic Flight Control Systems of being unable to handle flight uncertainties, and the need to construct control models manually. A robust Learning by Imitation approach is proposed which uses human pilots to demonstrate the task to be learned in a flight simulator while training datasets are captured from these demonstrations. The datasets are then used by Artificial Neural Networks to generate control models automatically. The control models imitate the skills of the human pilot when performing piloting tasks including handling flight uncertainties such as severe weather conditions. Experiments show that IAS performs learned take-off, climb, and slow ascent tasks with high accuracy even after being presented with limited examples, as measured by Mean Absolute Error and Mean Absolute Deviation. The results demonstrate that the IAS is capable of imitating low-level sub-cognitive skills such as rapid and continuous stabilization attempts in stormy weather conditions, and high-level strategic skills such as the sequence of sub-tasks necessary to pilot an aircraft starting from the stationary position on the runway, and ending with a steady cruise
Autonomous Landing and Go-around of Large Jets Under Severe Weather Conditions Using Artificial Neural Networks
We introduce the Intelligent Autopilot System (IAS) which is capable of autonomous landing, and go-around of large jets such as airliners under severe weather conditions. The IAS is a potential solution to the current problem of Automatic Flight Control Systems of being unable to autonomously handle flight uncertainties such as severe weather conditions, autonomous complete flights, and go-around. A robust approach to control the aircraft's bearing using Artificial Neural Networks is proposed. An Artificial Neural Network predicts the appropriate bearing to be followed given the drift from the path line to be intercepted. In addition, the capabilities of the Flight Manager of the IAS are extended to detect unsafe landing attempts, and generate a go-around flight course. Experiments show that the IAS can handle such flight skills and tasks effectively, and can even land aircraft under severe weather conditions that are beyond the maximum demonstrated landing of the aircraft model used in this work as reported by the manufacturer's operations limitations. The proposed IAS is a novel approach towards achieving full control autonomy of large jets using ANN models that match the skills and abilities of experienced human pilots
Opinion amplification causes extreme polarization in social networks
Extreme polarization of opinions fuels many of the problems facing our societies today, from issues on human rights to the environment. Social media provides the vehicle for these opinions and enables the spread of ideas faster than ever before. Previous computational models have suggested that significant external events can induce extreme polarization. We introduce the Social Opinion Amplification Model (SOAM) to investigate an alternative hypothesis: that opinion amplification can result in extreme polarization. SOAM models effects such as sensationalism, hype, or âfake newsâ as people express amplified versions of their actual opinions, motivated by the desire to gain a greater following. We show for the first time that this simple idea results in extreme polarization, especially when the degree of amplification is small. We further show that such extreme polarization can be prevented by two methods: preventing individuals from amplifying more than five times, or through consistent dissemination of balanced opinions to the population. It is natural to try and have the loudest voice in a crowd when we seek attention; this work suggests that instead of shouting to be heard and generating an uproar, it is better for all if we speak with moderation
Interacting Hierarchical Dynamic Networks
In this work we present IHDNs: an original model of computation for the simulation of interacting, dynamic, multi-scale systems. We show that a novel message passing mechanism that operates across layers of abstraction in hierarchical dynamic networks is effective in expressing the complex dependencies of living systems. Using a conventional computational model of cell evolution in cancerous tumour growth for comparison, we demonstrate the validity of IHDNs in emulating the behaviour of life-like systems, as well as the additional capabilities in enabling Neo4j Cypher patternmatching queries, demonstrated here in the analysis of evolutionary cell heritage
Improving Artificial-Immune-System-based computing by exploiting intrinsic features of computer architectures
Biological systems have become highly significant for traditional computer architectures as examples of highly complex self-organizing systems that perform tasks in parallel with no centralized control. However, few researchers have compared the suitability of different computing approaches for the unique features of Artificial Immune Systems (AIS) when trying to introduce novel computing architectures, and few consider the practicality of their solutions for real world machine learning problems. We propose that the efficacy of AIS-based computing for tackling real world datasets can be improved by the exploitation of intrinsic features of computer architectures. This paper reviews and evaluates current existing implementation solutions for AIS on different computing paradigms and introduces the idea of âC Principlesâ and âA Principlesâ. Three Artificial Immune Systems implemented on different architectures are compared using these principles to examine the possibility of improving AIS through taking advantage of intrinsic hardware features
Arranging the Pieces: A Survey of Library Practices Related to a Tabletop Game Collection
Objective â The purpose of this study is to explore collection development, cataloguing, processing, and circulation practices for tabletop game collections in libraries. This study used the term âtabletop gamesâ to refer to the array of game styles that are played in real-world, social settings, such as board games, dice and card games, collectible card games, and role-playing games. Evidence Based Library and Information Practice 2017, 12.1 3 Methods â An online survey regarding tabletop games in libraries was developed with input from academic, public, and school librarians. Participants were recruited utilizing a snowball sampling technique involving electronic outlets and discussion lists used by librarians in school, public, and academic libraries. Results â One hundred nineteen libraries answered the survey. The results show that tabletop games have a presence in libraries, but practices vary in regard to collection development, cataloguing, processing, and circulation. Conclusion â Results indicate that libraries are somewhat fragmented in their procedures for tabletop collections. Libraries can benefit from better understanding how others acquire, process, and use these collections. Although they are different to other library collections, tabletop games do not suffer from extensive loss and bibliographic records are becoming more available. Best practices and guidance are still needed to fully integrate games into libraries and to help librarians feel comfortable piloting their own tabletop collections
Teams Frightened of Failure Fail More: Modelling Reward Sensitivity in Teamwork
According to Gray's Reinforcement Sensitivity Theory (RST), individuals have differing sensitivities to rewards and punishments, which in turn affect their behaviours. The behavioural inhibition system (BIS) is associated with sensitivity to punishment while the behavioural activation system (BAS) is associated with sensitivity to reward. In this work, we model BIS/BAS by supplementing an existing agent-based model of team collaboration in order to explore the combined effect on team performance for a more complex and realistic personality structure. We investigate the significance of BIS/BAS on team behaviour for tasks with differing levels of uncertainty. Findings include a prediction that for tasks with uncertainty, a majority of personality types are significantly influenced by behavioural activation system, and that all personality types are significantly negatively influenced by behavioural inhibition system. The more sensitive to punishments, the worse teams perform
Evolving Through the Looking Glass: Learning Improved Search Spaces with Variational Autoencoders
Nature has spent billions of years perfecting our genetic representations, making them evolvable and expressive. Generative machine learning offers a shortcut: learn an evolvable latent space with implicit biases towards better solutions. We present SOLVE: Search space Optimization with Latent Variable Evolution, which creates a dataset of solutions that satisfy extra problem criteria or heuristics, generates a new latent search space, and uses a genetic algorithm to search within this new space to find solutions that meet the overall objective. We investigate SOLVE on five sets of criteria designed to detrimentally affect the search space and explain how this approach can be easily extended as the problems become more complex. We show that, compared to an identical GA using a standard representation, SOLVE with its learned latent representation can meet extra criteria and find solutions with distance to optimal up to two orders of magnitude closer. We demonstrate that SOLVE achieves its results by creating better search spaces that focus on desirable regions, reduce discontinuities, and enable improved search by the genetic algorithm. Fig. 1.Search space Optimization with Latent Variable Evolution (SOLVE). An optimizer produces a dataset of random solutions satisfying an extra criterion (e.g., constraint or secondary objective). A variational autoencoder learns this dataset and produces a learned latent representation biased towards the desired region of the search space. This learned representation is then used by a genetic algorithm to find solutions that meet the objective and extra criterion together
Investigating the Origins of Cancer in the Intestinal Crypt with a Gene Network Agent Based Hybrid Model
Colorectal cancer (CRC) is the second most common tumour in the world (Bray, 2018). It has been proposed that morbidity and mortality could be mitigated by screening methods that identify key genetic mutations in the DNA of a patientâs biosample (Traverso, 2002). However, for this to work, a theoretical understanding of the most likely mutations that initiate malignant transformation, and how they affect subsequent microevolution, is needed. Specifically, we hypothesise that there is a CRC-proliferative mutation that is more likely to be initially fixated in the crypt. To investigate this, we developed an agent-based model of cells in the colon crypt that shows emergent biological homeostasis at the tissue level from the cellular and molecular interactions. We equipped each of the cells with a molecular gene network which, in their wildtype state, regulates homeostasis in the crypt and recapitulates known behaviour. We identified and modelled key genes implicated in CRC which, when mutated, alter the rate of death and division of cells. We used this model to study the biological first principles of the fixation of mutations, offering key spatial and temporal understanding of this process. We discuss the impact and clinical relevance of proliferative genetic mutations in isolation, pointing to the KRAS gene as a likely mutation to be initially fixed in the crypt
T-DominO: Exploring Multiple Criteria with Quality-Diversity and the Tournament Dominance Objective
Real-world design problems are a messy combination of constraints, objectives, and features. Exploring these problem spaces can be defined as a Multi-Criteria Exploration (MCX) problem, whose goals are to produce a set of diverse solutions with high performance across many objectives, while avoiding low performance across any objectives. Quality-Diversity algorithms produce the needed design variation, but typically consider only a single objective. We present a new ranking, T-DominO, specifically designed to handle multiple objectives in MCX problems. T-DominO ranks individuals relative to other solutions in the archive, favoring individuals with balanced performance over those which excel at a few objectives at the cost of the others. Keeping only a single balanced solution in each MAP-Elites bin maintains the visual accessibility of the archive â a strong asset for design exploration. We illustrate our approach on a set of easily understood benchmarks, and showcase its potential in a many-objective real-world architecture case study
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