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Konstantinos Politopoulos

Publications and source records attributed to Konstantinos Politopoulos.

2 recordsLinked to original sources

A gamified simulator and physical platform for self-driving algorithm training and validation

We identify the need for a gamified self-driving simulator where game mechanics encourage high-quality data capture, and design and apply such a simulator to collecting lane-following training data. The resulting synthetic data enables a Convolutional Neural Network (CNN) to drive an in-game vehicle. We simultaneously develop a physical test platform based on a radio-controlled vehicle and the Robotic Operating System (ROS) and successfully transfer the simulation-trained model to the physical domain without modification. The cross-platform simulator facilitates unsupervised crowdsourcing, helping to collect diverse data emulating complex, dynamic environment data, infrequent events, and edge cases. The physical platform provides a low-cost solution for validating simulation-trained models or enabling rapid transfer learning, thereby improving the safety and resilience of self-driving algorithms.

cs.RO

Time evolution of photon-pulse propagation in scattering and absorbing media: The dynamic radiative transfer system

A new dynamic system approach to the problem of radiative transfer inside scattering and absorbing media is presented, directly based on firsthand physical principles. This method, the Dynamic Radiative Transfer System (DRTS), calculates accurately the time evolution of photon propagation in media of complex structure and shape. DRTS employs a dynamical system formality using a global sparse matrix which characterizes the physical, optical and geometrical properties of the material volume of interest. The new system state vector is generated by the above time-independent matrix, using simple matrix vector multiplication addition for each subsequent time step. DRTS simulation results are presented for 3D light propagation in different optical media, demonstrating greatly reduced computational cost and resource requirements compared to other methods. Flexibility of the method allows the integration of time-dependent sources, boundary conditions, different media and several optical phenomena like reflection and refraction in a unified and consistent way.

cond-mat.stat-mech