You must have heard of Dubai chocolate: the sticky, indulgent confectionary filled with pistachio cream, tahini and shreds of knafeh pastry, which has become a global sensation. Now the decadent bar has inspired South Korea's latest dessert craze. The Dubai chewy cookie has been selling like wildfire - and even restaurants that don't usually offer baked goods are trying to get a nibble of the market. Despite its name, the cookie's texture more closely resembles a rice cake, and is made by stuffing pistachio cream and knafeh shreds into a chocolate marshmallow. Shops are selling hundreds of cookies within minutes and the frenzy has sent prices of key ingredients surging, local media reported.

PySHRED is a Python package that implements the SHallow REcurrent D ecoder (SHRED) architecture (Figure 1) and provides a high-level interface for sensing, model reduction and physics discovery tasks. Originally proposed as a sensing strategy which is agnostic to sensor placement [1], SHRED provides a lightweight, data-driven framework for reconstructing and forecasting high-dimensional spatiotemporal states from sparse sensor measurements. SHRED achieves this by (i) encoding time-lagged sensor sequences into a low-dimensional latent space using a sequence model, and (ii) decoding these latent representations back into the full spatial field via a decoder model. Since its introduction as a sparse sensing algorithm, several specialized variants have been developed to extend SHRED's capabilities: SHRED-ROM for parametric reduced-order modeling SINDy-SHRED for discovering sparse latent dynamics and stable long-horizon forecasting Multi-field SHRED for modeling dynamically coupled fields PySHRED unifies these variants into a single open-source, extensible, and thoroughly documented Python package, which is also capable of training on compressed representations of the data, allowing for efficient laptop-level training of models. It is accompanied by a rich example gallery of Jupyter Notebook and Google Colab tutorials.

The Shallow Recurrent Decoder networks are a novel paradigm recently introduced for state estimation, combining sparse observations with high-dimensional model data. This architecture features important advantages compared to standard data-driven methods including: the ability to use only three sensors (even randomly selected) for reconstructing the entire dynamics of a physical system; the ability to train on compressed data spanned by a reduced basis; the ability to measure a single field variable (easy to measure) and reconstruct coupled spatio-temporal fields that are not observable and minimal hyper-parameter tuning. This approach has been verified on different test cases within different fields including nuclear reactors, even though an application to a real experimental facility, adopting the employment of in-situ observed quantities, is missing. This work aims to fill this gap by applying the Shallow Recurrent Decoder architecture to the DYNASTY facility, built at Politecnico di Milano, which studies the natural circulation established by internally heated fluids for Generation IV applications, especially in the case of Circulating Fuel reactors. The RELAP5 code is used to generate the high-fidelity data, and temperature measurements extracted by the facility are used as input for the state estimation. The results of this work will provide a validation of the Shallow Recurrent Decoder architecture to engineering systems, showing the capabilities of this approach to provide and accurate state estimation.

The recent developments in data-driven methods have paved the way to new methodologies to provide accurate state reconstruction of engineering systems; nuclear reactors represent particularly challenging applications for this task due to the complexity of the strongly coupled physics involved and the extremely harsh and hostile environments, especially for new technologies such as Generation-IV reactors. Data-driven techniques can combine different sources of information, including computational proxy models and local noisy measurements on the system, to robustly estimate the state. This work leverages the novel Shallow Recurrent Decoder architecture to infer the entire state vector (including neutron fluxes, precursors concentrations, temperature, pressure and velocity) of a reactor from three out-of-core time-series neutron flux measurements alone. In particular, this work extends the standard architecture to treat parametric time-series data, ensuring the possibility of investigating different accidental scenarios and showing the capabilities of this approach to provide an accurate state estimation in various operating conditions. This paper considers as a test case the Molten Salt Fast Reactor (MSFR), a Generation-IV reactor concept, characterised by strong coupling between the neutronics and the thermal hydraulics due to the liquid nature of the fuel. The promising results of this work are further strengthened by the possibility of quantifying the uncertainty associated with the state estimation, due to the considerably low training cost. The accurate reconstruction of every characteristic field in real-time makes this approach suitable for monitoring and control purposes in the framework of a reactor digital twin.

Sensing is one of the most fundamental tasks for the monitoring, forecasting and control of complex, spatio-temporal systems. In many applications, a limited number of sensors are mobile and move with the dynamics, with examples including wearable technology, ocean monitoring buoys, and weather balloons. In these dynamic systems (without regions of statistical-independence), the measurement time history encodes a significant amount of information that can be extracted for critical tasks. Most model-free sensing paradigms aim to map current sparse sensor measurements to the high-dimensional state space, ignoring the time-history all together. Using modern deep learning architectures, we show that a sequence-to-vector model, such as an LSTM (long, short-term memory) network, with a decoder network, dynamic trajectory information can be mapped to full state-space estimates. Indeed, we demonstrate that by leveraging mobile sensor trajectories with shallow recurrent decoder networks, we can train the network (i) to accurately reconstruct the full state space using arbitrary dynamical trajectories of the sensors, (ii) the architecture reduces the variance of the mean-square error of the reconstruction error in comparison with immobile sensors, and (iii) the architecture also allows for rapid generalization (parameterization of dynamics) for data outside the training set. Moreover, the path of the sensor can be chosen arbitrarily, provided training data for the spatial trajectory of the sensor is available. The exceptional performance of the network architecture is demonstrated on three applications: turbulent flows, global sea-surface temperature data, and human movement biomechanics.

We present SHRED, a method for 3D SHape REgion Decomposition. SHRED takes a 3D point cloud as input and uses learned local operations to produce a segmentation that approximates fine-grained part instances. We endow SHRED with three decomposition operations: splitting regions, fixing the boundaries between regions, and merging regions together. Modules are trained independently and locally, allowing SHRED to generate high-quality segmentations for categories not seen during training. We train and evaluate SHRED with fine-grained segmentations from PartNet; using its merge-threshold hyperparameter, we show that SHRED produces segmentations that better respect ground-truth annotations compared with baseline methods, at any desired decomposition granularity. Finally, we demonstrate that SHRED is useful for downstream applications, out-performing all baselines on zero-shot fine-grained part instance segmentation and few-shot fine-grained semantic segmentation when combined with methods that learn to label shape regions.

Tony Hawk knows that his last video game, Pro Skater 5, was a flop. The PS4 version has a 32 rating on Metacritic, a site that aggregates review scores from IGN, Game Informer and other media outlets. The PS1 version of Pro Skater 2, for comparison, has a near-perfect 98 rating, while Pro Skater 3 and 4, developed primarily for the PS2, have 97 and 94 scores respectively. Tony Hawk-branded video games have been inconsistent since 2007's Proving Ground, the last title developed by series pioneer Neversoft Entertainment. Tony Hawk: Ride and Shred, which revolved around a physical skateboard peripheral, were a gimmicky mess.