Inspired by the success of Simulated Annealing in physics, we transfer insights and adaptations to the scheduling domain, specifically addressing the one-stage job scheduling problem with an arbitrary number of parallel machines. In optimization, challenges arise from local optima, plateaus in the loss surface, and computationally complex Hamiltonian (cost) functions. To overcome these issues, we propose the integration of corrective actions, including symmetry breaking, restarts, and freezing out non-optimal fluctuations, into the Metropolis-Hastings algorithm. Additionally, we introduce a generalized Hamiltonian that efficiently fuses straightforward but widely applied processing-time cost functions. Our approach outperforms decision rules, meta-heuristics, and novel reinforcement learning algorithms. Notably, our method achieves these superior results in real-time, thanks to its computationally efficient evaluation of the Hamiltonian.
The curse of dimensionality refers to phenomena occurring with increasing dimensionality such as marginal differences in distances. Projection pursuit solves this issue by projecting high-dimensional data into a low-dimensional space where meaningful distances allow unbiased function estimation. However, projection pursuit only considers projections onto lines and the unbiased function depends on the sample size. We introduce deep projection pursuit (DPP) to remedy these limitations by using an ensemble of projections on parameterized surfaces combined with neural networks to solve the learning task. Furthermore, we demonstrate the capabilities of the DPP framework by training principal component curves and solving supervised tasks with interpretable models. Finally, we show the ability to maintain group properties in the projection space. Due to these applications, deep projection pursuit is a flexible design paradigm with various use cases.
Traffic signal control plays a crucial role in urban mobility. However, existing methods often struggle to generalize beyond their training environments to unseen scenarios with varying traffic dynamics. We present TransferLight, a novel framework designed for robust generalization across road-networks, diverse traffic conditions and intersection geometries. At its core, we propose a log-distance reward function, offering spatially-aware signal prioritization while remaining adaptable to varied lane configurations - overcoming the limitations of traditional pressure-based rewards. Our hierarchical, heterogeneous, and directed graph neural network architecture effectively captures granular traffic dynamics, enabling transferability to arbitrary intersection layouts. Using a decentralized multi-agent approach, global rewards, and novel state transition priors, we develop a single, weight-tied policy that scales zero-shot to any road network without re-training. Through domain randomization during training, we additionally enhance generalization capabilities. Experimental results validate TransferLight's superior performance in unseen scenarios, advancing practical, generalizable intelligent transportation systems to meet evolving urban traffic demands.
Deep neural networks are applied in more and more areas of everyday life. However, they still lack essential abilities, such as robustly dealing with spatially transformed input signals. Approaches to mitigate this severe robustness issue are limited to two pathways: Either models are implicitly regularised by increased sample variability (data augmentation) or explicitly constrained by hard-coded inductive biases. The limiting factor of the former is the size of the data space, which renders sufficient sample coverage intractable. The latter is limited by the engineering effort required to develop such inductive biases for every possible scenario. Instead, we take inspiration from human behaviour, where percepts are modified by mental or physical actions during inference. We propose a novel technique to emulate such an inference process for neural nets. This is achieved by traversing a sparsified inverse transformation tree during inference using parallel energy-based evaluations. Our proposed inference algorithm, called Inverse Transformation Search (ITS), is model-agnostic and equips the model with zero-shot pseudo-invariance to spatially transformed inputs. We evaluated our method on several benchmark datasets, including a synthesised ImageNet test set. ITS outperforms the utilised baselines on all zero-shot test scenarios.
Nearly all state of the art vision models are sensitive to image rotations. Existing methods often compensate for missing inductive biases by using augmented training data to learn pseudo-invariances. Alongside the resource demanding data inflation process, predictions often poorly generalize. The inductive biases inherent to convolutional neural networks allow for translation equivariance through kernels acting parallely to the horizontal and vertical axes of the pixel grid. This inductive bias, however, does not allow for rotation equivariance. We propose a radial beam sampling strategy along with radial kernels operating on these beams to inherently incorporate center-rotation covariance. Together with an angle distance loss, we present a radial beam-based image canonicalization model, short BIC. Our model allows for maximal continuous angle regression and canonicalizes arbitrary center-rotated input images. As a pre-processing model, this enables rotation-invariant vision pipelines with model-agnostic rotation-sensitive downstream predictions. We show that our end-to-end trained angle regressor is able to predict continuous rotation angles on several vision datasets, i.e. FashionMNIST, CIFAR10, COIL100, and LFW.
The reliability of systems that use machine learning to recognize the human working in an industrial environment is of high importance for the employee safety. we present a framework which is capable of recognizing the person's natural interaction with an industrial machine. We focus on the application of human action recognition in the context of machine operation by skilled workers in industrial or commercial environments. We propose a framework that includes action recognition as part of a software component for understanding behavior. For our use case, we defined an exemplary machine operation workflow which we use to compare five different neural networks in terms of prediction accuracy and real-time capabilities. Moreover, we compare different input shapes as the resolution of input images and the size of the possible 3D-volume in order to study the robustness of the models. For our evaluation, we created our own custom dataset containing six action classes. Our analysis shows that the best model is the I3D with color images, a resolution of 112 × 112 pixels and 16 consecutive frames. The I3D also exhibited the best run-time performance for real-time applications.
The article investigates the application of NeuroEvolution of Augmenting Topologies (NEAT) to generate and parameterize artificial neural networks (ANN) on determining allocation and sequencing decisions in a two-stage hybrid flow shop scheduling environment with family setup times. NEAT is a machine-learning and neural architecture search algorithm, which generates both, the structure and the hyper-parameters of an ANN. Our experiments show that NEAT can compete with state-of-the-art approaches in terms of solution quality and outperforms them regarding computational efficiency. The main contributions of this article are: (i) A comparison of five different strategies, evaluated with 14 different experiments, on how ANNs can be applied for solving allocation and sequencing problems in a hybrid flow shop environment, (ii) a comparison of the best identified NEAT strategy with traditional heuristic and metaheuristic approaches concerning solution quality and computational efficiency.
Scheduling still constitutes a challenging problem, especially for complex problem settings involving due dates and sequence-dependent setups. The majority of existing approaches use heuristics or meta-heuristics, like Genetic Algorithms or Reinforcement Learning. We show that a supervised learning framework can learn and generalize from generated optimal target schedules, which amplifies convergence compared to unsupervised methods. We present a deep hybrid greedy framework, which can predict near-optimal schedules by utilizing the following key mechanisms: (i) Through the interplay between heuristics and a deep neural network our hybrid model can combine the benefits. Specifically, complex patterns from optimal schedules can be learned by a neural network. We reduce the computational costs by outsourcing trivial decisions to heuristics and therefore, allowing consistent decisions during training. (ii) The problem complexity can be reduced, by employing a greedy prediction scheme, where one job at a time is predicted. (iii) We propose a re-scheduling mechanism for idle jobs, which enables long-term cost reduction and renders the framework reactive and dynamic. Through the heuristics and the neural network, our model is real-time capable during inference. We compare our model against prevailing scheduling heuristics and our model outperformed one of them in terms of makespan and lateness minimization. The key purpose of this work is to give a proof of concept, that supervised learning is applicable for complex scheduling problems.