Agents
Natural Way of Solving a Convex Hull Problem
Saadati, Sina, Razzazi, Mohammadreza
In this article, a new solution for the convex hull problem has been presented. The convex hull is a widely known problem in computational geometry. As nature is a rich source of ideas in the field of algorithms, the solution has been inspired by nature. A tight elastic band is modeled using agents and also nails as points of the problem. By simulating an elastic band with nails in an environment, solving the convex hull problem will be possible. The algorithm runs in O(t) in which t is the time that an elastic band will get fixed.
Sequential Decision Problems with Weak Feedback
This thesis considers sequential decision problems, where the loss/reward incurred by selecting an action may not be inferred from observed feedback. A major part of this thesis focuses on the unsupervised sequential selection problem, where one can not infer the loss incurred for selecting an action from observed feedback. We also introduce a new setup named Censored Semi Bandits, where the loss incurred for selecting an action can be observed under certain conditions. Finally, we study the channel selection problem in the communication networks, where the reward for an action is only observed when no other player selects that action to play in the round. These problems find applications in many fields like healthcare, crowd-sourcing, security, adaptive resource allocation, among many others. This thesis aims to address the above-described sequential decision problems by exploiting specific structures these problems exhibit. We develop provably optimal algorithms for each of these setups with weak feedback and validate their empirical performance on different problem instances derived from synthetic and real datasets.
Towards Continual Reinforcement Learning: A Review and Perspectives
Khetarpal, Khimya | Riemer, Matthew (a:1:{s:5:"en_US";s:42:"IBM Research, Mila, University of Montreal";}) | Rish, Irina | Precup, Doina
In this article, we aim to provide a literature review of different formulations and approaches to continual reinforcement learning (RL), also known as lifelong or non-stationary RL. We begin by discussing our perspective on why RL is a natural fit for studying continual learning. We then provide a taxonomy of different continual RL formulations by mathematically characterizing two key properties of non-stationarity, namely, the scope and driver non-stationarity. This offers a unified view of various formulations. Next, we review and present a taxonomy of continual RL approaches. We go on to discuss evaluation of continual RL agents, providing an overview of benchmarks used in the literature and important metrics for understanding agent performance. Finally, we highlight open problems and challenges in bridging the gap between the current state of continual RL and findings in neuroscience. While still in its early days, the study of continual RL has the promise to develop better incremental reinforcement learners that can function in increasingly realistic applications where non-stationarity plays a vital role. These include applications such as those in the fields of healthcare, education, logistics, and robotics.
Intelligent Autonomous Systems Engineer
My client, a world leader in the defence sector, requires an Machine Learning Algorithm Developer to join them in Bristol and work as part of a team on the development and evaluation of state-of-the-art algorithms for the guidance, control and navigation of their missile and weapon systems.
The Machine Learning Algorithm Developer will work within a team of Intelligent Systems, Autonomous Systems and Command and Control Engineers to develop and evaluate state-of-the-art algorithms across a range of domains from on-board, autonomous decision making to off-board algorithms. The work will involve the research, development, test, evaluation and implementation of algorithms that integrate into complex guided weapon systems products.
Algorithms are central to the design of sophisticated guided weapon systems products. These algorithms are developed throughout the lifecycle of the product and include research studies to investigate algorithms for future developments.
Machine Learning Algorithm Developers are involved in the lifecycle of projects, playing a pivotal role in our product developments including:
Technical development of specific algorithms or studies for key programmes.Feasibility studies, algorithm design and trade-off studies, preparing trials, trials analysis and reporting, defining architecture, validating algorithms and models.Technical assessments and investigations into a full range of issues and problems and prepare and develop solutions either solely or as a member of a project team.Engaging with the algorithm users, understanding and responding to their needs and ensure that the algorithms are fit for purpose.
You will gain exposure to a range of other related subject areas e.g. Simulation and Modelling, Software, Hardware-in-the Loop, Systems Design & Validation, Seekers & Sensors, Datalinks and Technical Quality and will be exposed to cutting-edge technological innovations, playing a meaningful role through the development of complex weapon systems.
To be considered for this role, applicants will ideally have completed (or be soon to complete) a PhD level in a related area with a good degree in a subject with strong mathematical content and programming skills e.g. Engineering, Mathematics, Physics, Computer Science, Information Engineering.
You will have previous experience in the development and practical application of algorithms, with experience in some of the following:
Robotics, data fusion, tracking/estimation, pattern discovery & recognition, statistical inference, optimisation and machine/deep learning algorithms along with real-time implementation, and/or validation & verification.
You will also have experience in some of the following: Matlab, Simulink, Stateflow, Python including PyTorch, TensorFlow, Open AI-Gym/Universe, Model Based Design.
Specific knowledge or experience in any of these areas would also be ideal:
Robotics, guidance and autonomous decision making, e.g. Routing and motion/trajectory planning, optimisation, co-ordinated guidance and control, decision theory, MDPs/POMDPs, specialist systems, game theory, decision support systems, multi-agent systemsData fusion and state estimation/tracking algorithms e.g. Kalman Filtering, multiple-model tracking methods, particle filters, grid-based estimation methods, Multi-Object-Multi-Sensor Fusion, data-association, random finite sets, Bayesian belief networks, Dempster-Shafer theory of evidenceMachine Learning for regression and pattern recognition/discovery problems e.g. Gaussian processes, latent variable methods, support vector machines, probabilistic/statistical models, neural networks, Bayesian inference, random-forests, novelty detection, clusteringDeep Learning e.g. Deep reinforcement learning, Monte-Carlo tree search, deep regression/classification, deep embeddings, recurrent Networks, natural language processingComputer Vision algorithms e.g. Structure from motion, image Based navigation, SLAM, pose estimation/recovery
Machine Learning Algorithm Developer
Bristol
Salary £35-50k plus benefits DOE
Key Skills: Intelligent Systems Engineer, Intelligent Autonomous Systems Engineer, IAS Engineer, PhD, Mathematics, Algorithms, Programming, Robotics, Autonomous Decision Making, Machine Learning, Deep Learning, Data Fusion, Pattern Discovery, Pattern Recognition, Computer Vision, Machine Vision, Matlab, Simulink, Stateflow, Python, PyTorch
Due to the nature of work undertaken at our client's site, incumbents of these positions are required to meet special nationality rules and therefore these vacancies are only open to sole British Citizens. Applicants who meet these criteria will also be required to undergo security clearance vetting, if not already security cleared to a minimum SC level.
Electus Recruitment Solutions provides specialist engineering and technical recruitment solutions to a number of high technology industries. We thank you for your interest in this vacancy. If you don't hear from us within 7 working days please presume your application has been unsuccessful on this occasion. You are of course free to resubmit your CV/details in the future and we shall assess your suitability at that time.
This role is a PERMANENT position
GCS-Q: Quantum Graph Coalition Structure Generation
Venkatesh, Supreeth Mysore, Macaluso, Antonio, Klusch, Matthias
The problem of generating an optimal coalition structure for a given coalition game of rational agents is to find a partition that maximizes their social welfare and is known to be NP-hard. This paper proposes GCS-Q, a novel quantum-supported solution for Induced Subgraph Games (ISGs) in coalition structure generation. GCS-Q starts by considering the grand coalition as initial coalition structure and proceeds by iteratively splitting the coalitions into two nonempty subsets to obtain a coalition structure with a higher coalition value. The problem of coalition structure generation (CSG) is to find a partition of n rational agents into mutually disjoint coalitions such that the sum of the resulting coalition values for this coalition structure is maximized. For a given coalition game (A, v), the coalition structures CS are partitions of A into mutually disjoint, feasible coalitions C. The corresponding ISG is to find the optimal coalition structure CS In ISGs, the coalition values depend only on the pairwise interactions between nodes/agents.
Strategic multi-task coordination over regular networks of robots with limited computation and communication capabilities
Wei, Yi, Vasconcelos, Marcos M.
Coordination is a desirable feature in multi-agent systems, allowing the execution of tasks that would be impossible by individual agents. We study coordination by a team of strategic agents choosing to undertake one of the multiple tasks. We adopt a stochastic framework where the agents decide between two distinct tasks whose difficulty is randomly distributed and partially observed. We show that a Nash equilibrium with a simple and intuitive linear structure exists for diffuse prior distributions on the task difficulties. Additionally, we show that the best response of any agent to an affine strategy profile can be nonlinear when the prior distribution is not diffuse. Finally, we state an algorithm that allows us to efficiently compute a data-driven Nash equilibrium within the class of affine policies.
Hyperparameters in Contextual RL are Highly Situational
Eimer, Theresa, Benjamins, Carolin, Lindauer, Marius
Although Reinforcement Learning (RL) has shown impressive results in games and simulation, real-world application of RL suffers from its instability under changing environment conditions and hyperparameters. We give a first impression of the extent of this instability by showing that the hyperparameters found by automatic hyperparameter optimization (HPO) methods are not only dependent on the problem at hand, but even on how well the state describes the environment dynamics. Specifically, we show that agents in contextual RL require different hyperparameters if they are shown how environmental factors change. In addition, finding adequate hyperparameter configurations is not equally easy for both settings, further highlighting the need for research into how hyperparameters influence learning and generalization in RL.
Knowledge-driven Scene Priors for Semantic Audio-Visual Embodied Navigation
Tatiya, Gyan, Francis, Jonathan, Bondi, Luca, Navarro, Ingrid, Nyberg, Eric, Sinapov, Jivko, Oh, Jean
Generalisation to unseen contexts remains a challenge for embodied navigation agents. In the context of semantic audio-visual navigation (SAVi) tasks, the notion of generalisation should include both generalising to unseen indoor visual scenes as well as generalising to unheard sounding objects. However, previous SAVi task definitions do not include evaluation conditions on truly novel sounding objects, resorting instead to evaluating agents on unheard sound clips of known objects; meanwhile, previous SAVi methods do not include explicit mechanisms for incorporating domain knowledge about object and region semantics. These weaknesses limit the development and assessment of models' abilities to generalise their learned experience. In this work, we introduce the use of knowledge-driven scene priors in the semantic audio-visual embodied navigation task: we combine semantic information from our novel knowledge graph that encodes object-region relations, spatial knowledge from dual Graph Encoder Networks, and background knowledge from a series of pre-training tasks -- all within a reinforcement learning framework for audio-visual navigation. We also define a new audio-visual navigation sub-task, where agents are evaluated on novel sounding objects, as opposed to unheard clips of known objects. We show improvements over strong baselines in generalisation to unseen regions and novel sounding objects, within the Habitat-Matterport3D simulation environment, under the SoundSpaces task.
Stochastic Nonlinear Ensemble Modeling and Control for Robot Team Environmental Monitoring
Edwards, Victoria, Silva, Thales C., Hsieh, M. Ani
We seek methods to model, control, and analyze robot teams performing environmental monitoring tasks. During environmental monitoring, the goal is to have teams of robots collect various data throughout a fixed region for extended periods of time. Standard bottom-up task assignment methods do not scale as the number of robots and task locations increases and require computationally expensive replanning. Alternatively, top-down methods have been used to combat computational complexity, but most have been limited to the analysis of methods which focus on transition times between tasks. In this work, we study a class of nonlinear macroscopic models which we use to control a time-varying distribution of robots performing different tasks throughout an environment. Our proposed ensemble model and control maintains desired time-varying populations of robots by leveraging naturally occurring interactions between robots performing tasks. We validate our approach at multiple fidelity levels including experimental results, suggesting the effectiveness of our approach to perform environmental monitoring.
Hidden-Variables Genetic Algorithm for Variable-Size Design Space Optimal Layout Problems with Application to Aerospace Vehicles
Gamot, Juliette, Balesdent, Mathieu, Tremolet, Arnault, Wuilbercq, Romain, Melab, Nouredine, Talbi, El-Ghazali
The optimal layout of a complex system such as aerospace vehicles consists in placing a given number of components in a container in order to minimize one or several objectives under some geometrical or functional constraints. This paper presents an extended formulation of this problem as a variable-size design space (VSDS) problem to take into account a large number of architectural choices and components allocation during the design process. As a representative example of such systems, considering the layout of a satellite module, the VSDS aspect translates the fact that the optimizer has to choose between several subdivisions of the components. For instance, one large tank of fuel might be placed as well as two smaller tanks or three even smaller tanks for the same amount of fuel. In order to tackle this NP-hard problem, a genetic algorithm enhanced by an adapted hidden-variables mechanism is proposed. This latter is illustrated on a toy case and an aerospace application case representative to real world complexity to illustrate the performance of the proposed algorithms. The results obtained using the proposed mechanism are reported and analyzed.