42,865 research outputs found
EvoTanks: co-evolutionary development of game-playing agents
This paper describes the EvoTanks research project, a continuing attempt to develop strong AI players for a primitive 'Combat' style video game using evolutionary computational methods with artificial neural networks. A small but challenging feat due to the necessity for agent's actions to rely heavily on opponent behaviour. Previous investigation has shown the agents are capable of developing high performance behaviours by evolving against scripted opponents; however these are local to the trained opponent. The focus of this paper shows results from the use of co-evolution on the same population. Results show agents no longer succumb to trappings of local maxima within the search space and are capable of converging on high fitness behaviours local to their population without the use of scripted opponents
Embodied Evolution in Collective Robotics: A Review
This paper provides an overview of evolutionary robotics techniques applied
to on-line distributed evolution for robot collectives -- namely, embodied
evolution. It provides a definition of embodied evolution as well as a thorough
description of the underlying concepts and mechanisms. The paper also presents
a comprehensive summary of research published in the field since its inception
(1999-2017), providing various perspectives to identify the major trends. In
particular, we identify a shift from considering embodied evolution as a
parallel search method within small robot collectives (fewer than 10 robots) to
embodied evolution as an on-line distributed learning method for designing
collective behaviours in swarm-like collectives. The paper concludes with a
discussion of applications and open questions, providing a milestone for past
and an inspiration for future research.Comment: 23 pages, 1 figure, 1 tabl
The impact of cellular characteristics on the evolution of shape homeostasis
The importance of individual cells in a developing multicellular organism is
well known but precisely how the individual cellular characteristics of those
cells collectively drive the emergence of robust, homeostatic structures is
less well understood. For example cell communication via a diffusible factor
allows for information to travel across large distances within the population,
and cell polarisation makes it possible to form structures with a particular
orientation, but how do these processes interact to produce a more robust and
regulated structure? In this study we investigate the ability of cells with
different cellular characteristics to grow and maintain homeostatic structures.
We do this in the context of an individual-based model where cell behaviour is
driven by an intra-cellular network that determines the cell phenotype. More
precisely, we investigated evolution with 96 different permutations of our
model, where cell motility, cell death, long-range growth factor (LGF),
short-range growth factor (SGF) and cell polarisation were either present or
absent. The results show that LGF has the largest positive impact on the
fitness of the evolved solutions. SGF and polarisation also contribute, but all
other capabilities essentially increase the search space, effectively making it
more difficult to achieve a solution. By perturbing the evolved solutions, we
found that they are highly robust to both mutations and wounding. In addition,
we observed that by evolving solutions in more unstable environments they
produce structures that were more robust and adaptive. In conclusion, our
results suggest that robust collective behaviour is most likely to evolve when
cells are endowed with long range communication, cell polarisation, and
selection pressure from an unstable environment
Evolution of environment dependent galaxy properties in the Sloan Digital Sky Survey
We use photometric redshifts to analyse the effect of local environment on
galaxy colours at redshifts z < 0.63 in the SDSS data release 6. We construct
mock SDSS-DR6 catalogues using semi-analytic galaxies to study possible
systematic effects on the characterisation of environment and colour statistics
due to the uncertainty in the determination of redshifts. We use the projected
galaxy density derived from the distance to the nearest neighbours with a
suitable radial velocity threshold to take into account the uncertainties in
the photometric redshift estimates. Our findings indicate that the use of
photometric redshifts greatly improves estimates of projected local galaxy
density when galaxy spectra are not available. We find a tight relationship
between spectroscopic and photometric derived densities, both in the SDSS-DR6
data (up to z=0.3) and mock catalogues (up to z=0.63).
At z=0, faint galaxies show a clear increase of the red galaxy fraction as
the local density increases. Bright galaxies, on the other hand, show a
constant red galaxy fraction. We are able to track the evolution of this
fraction to z=0.55 for galaxies brighter than M_r=-21.5 and find that the
fraction of blue galaxies with respect to the total population progressively
becomes higher as the redshift increases, at a rate of 15% Gyr. Also, at any
given redshift, bright galaxies show a larger red population, indicating that
the star-formation activity shifts towards smaller objects as the redshift
decreases.Comment: 9 pages, 6 figures. Accepted by MNRA
The vulnerability of rules in complex work environments: dynamism and uncertainty pose problems for cognition
Many complex work environments rely heavily on cognitive operators using rules. Operators sometimes fail to implement rules, with catastrophic human, social and economic costs. Rule-based error is widely reported, yet the mechanisms of rule vulnerability have received less attention. This paper examines rule vulnerability in the complex setting of airline transport operations. We examined ‘the stable approach criteria rule’, which acts as a system defence during the approach to land. The study experimentally tested whether system state complexity influenced rule failure. The results showed increased uncertainty and dynamism led to increased likelihood of rule failure. There was also an interaction effect, indicating complexity from different sources can combine to further constrain rule-based response. We discuss the results in relation to recent aircraft accidents and suggest that ‘rule-based error’ could be progressed to embrace rule vulnerability, fragility and failure. This better reflects the influence that system behaviour and cognitive variety have on rule-based response. Practitioner Summary: In this study, we examined mechanisms of rule vulnerability in the complex setting of airline transport operations. The results suggest work scenarios featuring high uncertainty and dynamism constrain rule-based response, leading to rules becoming vulnerable, fragile or failing completely. This has significant implications for rule-intensive, safety critical work environments
Neuro-evolution search methodologies for collective self-driving vehicles
Recently there has been an increasing amount of research into autonomous vehicles for real-world driving. Much progress has been made in the past decade with many automotive manufacturers demonstrating real-world prototypes. Current predictions indicate that roads designed exclusively for autonomous vehicles will be constructed and thus this thesis explores the use of methods to automatically produce controllers for autonomous vehicles that must navigate with each other on these roads. Neuro-Evolution, a method that combines evolutionary algorithms with neural networks, has shown to be effective in reinforcement-learning, multi-agent tasks such as maze navigation, biped locomotion, autonomous racing vehicles and fin-less rocket control. Hence, a neuro-evolution method is selected and investigated for the controller evolution of collective autonomous vehicles in homogeneous teams. The impact of objective and non-objective search (and a combination of both, a hybrid method) for controller evolution is comparatively evaluated for robustness on a range of driving tasks and collection sizes. Results indicate that the objective search was able to generalise the best on unseen task environments compared to all other methods and the hybrid approach was able to yield desired task performance on evolution far earlier than both approaches but was unable to generalise as effectively over new environments
Co-evolutionary dynamics in strategic alliances : the influence of the industry lifecycle
This study examines the application of the co-evolution literature to strategic alliance formation in SME’s in the UK and Australia in two differing industries at different stages of the industry life-cycle. Extending the framework developed by Das and Teng (2002) and that of Wilson and Hynes (2009), it engages with wider industry and environmental characteristics present in these two countries, specifically examining whether different theories of alliance formation are better suited to different stages of an industry life cycle. The issues discussed above are explored and developed through the use of a qualitative case study approach. Findings indicate strong resource-based drivers for alliance formation in both industries, with firms dependent on the co-evolution of their alliances and indeed selected by the results of their alliance participation. However, differences emerged in the strategic use of alliances in these two industries. The influence of the stage of the industry life cycle on this is discussed
Is project management the new management 2.0?
This paper considers the evolving nature of project management (PM) and offers a comparison with the evolving nature of management generally. Specifically, we identify a number of management trends that are drawn from a paper that documents a proposed ‘Management 2.0’ model, and we compare those trends to the way in which PM is maturing to embrace the challenges of modern organizational progress.Some theoretical frameworks are offered that assist in explaining the shift from the historically accepted ‘tools and techniques’ model to a more nuanced and behaviorally driven paradigm that is arguably more appropriate to manage change in today’s flexible and progressive organizations, and which provide a more coherent response, both in PM and traditional management, to McDonald’s forces. In addition, we offer a number of examples to robustly support our assertions, based around the development of innovative products from Apple Inc. In using this metaphor to demonstrate the evolution of project-based work, we link PM with innovation and new product development.
Rich environments for active learning: a definition
Rich Environments for Active Learning, or REALs, are comprehensive instructional systems that evolve from and are consistent with constructivist philosophies and theories. To embody a constructivist view of learning, REALs: promote study and investigation within authentic contexts; encourage the growth of student responsibility, initiative, decision making, and intentional learning; cultivate collaboration among students and teachers; utilize dynamic, interdisciplinary, generative learning activities that promote higher-order thinking processes to help students develop rich and complex knowledge structures; and assess student progress in content and learning-to-learn within authentic contexts using realistic tasks and performances. REALs provide learning activities that engage students in a continuous collaborative process of building and reshaping understanding as a natural consequence of their experiences and interactions within learning environments that authentically reflect the world around them. In this way, REALs are a response to educational practices that promote the development of inert knowledge, such as conventional teacher-to-student knowledge-transfer activities. In this article, we describe and organize the shared elements of REALs, including the theoretical foundations and instructional strategies to provide a common ground for discussion. We compare existing assumptions underlying education with new assumptions that promote problem-solving and higher-level thinking. Next, we examine the theoretical foundation that supports these new assumptions. Finally, we describe how REALs promote these new assumptions within a constructivist framework, defining each REAL attribute and providing supporting examples of REAL strategies in action
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