Africa
Graph Neural Networks with Parallel Neighborhood Aggregations for Graph Classification
Doshi, Siddhant, Chepuri, Sundeep Prabhakar
We focus on graph classification using a graph neural network (GNN) model that precomputes the node features using a bank of neighborhood aggregation graph operators arranged in parallel. These GNN models have a natural advantage of reduced training and inference time due to the precomputations but are also fundamentally different from popular GNN variants that update node features through a sequential neighborhood aggregation procedure during training. We provide theoretical conditions under which a generic GNN model with parallel neighborhood aggregations (PA-GNNs, in short) are provably as powerful as the well-known Weisfeiler-Lehman (WL) graph isomorphism test in discriminating non-isomorphic graphs. Although PA-GNN models do not have an apparent relationship with the WL test, we show that the graph embeddings obtained from these two methods are injectively related. We then propose a specialized PA-GNN model, called SPIN, which obeys the developed conditions. We demonstrate via numerical experiments that the developed model achieves state-of-the-art performance on many diverse real-world datasets while maintaining the discriminative power of the WL test and the computational advantage of preprocessing graphs before the training process.
Towards Improving Embedding Based Models of Social Network Alignment via Pseudo Anchors
Yan, Zihan, Liu, Li, Li, Xin, Cheung, William K., Zhang, Youmin, Liu, Qun, Wang, Guoyin
Social network alignment aims at aligning person identities across social networks. Embedding based models have been shown effective for the alignment where the structural proximity preserving objective is typically adopted for the model training. With the observation that ``overly-close'' user embeddings are unavoidable for such models causing alignment inaccuracy, we propose a novel learning framework which tries to enforce the resulting embeddings to be more widely apart among the users via the introduction of carefully implanted pseudo anchors. We further proposed a meta-learning algorithm to guide the updating of the pseudo anchor embeddings during the learning process. The proposed intervention via the use of pseudo anchors and meta-learning allows the learning framework to be applicable to a wide spectrum of network alignment methods. We have incorporated the proposed learning framework into several state-of-the-art models. Our experimental results demonstrate its efficacy where the methods with the pseudo anchors implanted can outperform their counterparts without pseudo anchors by a fairly large margin, especially when there only exist very few labeled anchors.
General Board Geometry
Browne, Cameron, Piette, Éric, Stephenson, Matthew, Soemers, Dennis J. N. J.
Game boards are described in the Ludii general game system by their underlying graphs, based on tiling, shape and graph operators, with the automatic detection of important properties such as topological relationships between graph elements, directions and radial step sequences. This approach allows most conceivable game boards to be described simply and succinctly.
Off-Policy Correction For Multi-Agent Reinforcement Learning
Zawalski, Michał, Osiński, Błażej, Michalewski, Henryk, Miłoś, Piotr
Multi-agent reinforcement learning (MARL) provides a framework for problems involving multiple interacting agents. Despite apparent similarity to the single-agent case, multi-agent problems are often harder to train and analyze theoretically. In this work, we propose MA-Trace, a new on-policy actor-critic algorithm, which extends V-Trace to the MARL setting. The key advantage of our algorithm is its high scalability in a multi-worker setting. To this end, MA-Trace utilizes importance sampling as an off-policy correction method, which allows distributing the computations with no impact on the quality of training. Furthermore, our algorithm is theoretically grounded - we prove a fixed-point theorem that guarantees convergence. We evaluate the algorithm extensively on the StarCraft Multi-Agent Challenge, a standard benchmark for multi-agent algorithms. MA-Trace achieves high performance on all its tasks and exceeds state-of-the-art results on some of them.
Neural Program Generation Modulo Static Analysis
Mukherjee, Rohan, Wen, Yeming, Chaudhari, Dipak, Reps, Thomas W., Chaudhuri, Swarat, Jermaine, Chris
State-of-the-art neural models of source code tend to be evaluated on the generation of individual expressions and lines of code, and commonly fail on long-horizon tasks such as the generation of entire method bodies. We propose to address this deficiency using weak supervision from a static program analyzer. Our neurosymbolic method allows a deep generative model to symbolically compute, using calls to a static-analysis tool, long-distance semantic relationships in the code that it has already generated. During training, the model observes these relationships and learns to generate programs conditioned on them. We apply our approach to the problem of generating entire Java methods given the remainder of the class that contains the method. Our experiments show that the approach substantially outperforms state-of-the-art transformers and a model that explicitly tries to learn program semantics on this task, both in terms of producing programs free of basic semantic errors and in terms of syntactically matching the ground truth.
Design of an Novel Spectrum Sensing Scheme Based on Long Short-Term Memory and Experimental Validation
Choudhury, Nupur, Sarma, Kandarpa Kumar, Kalita, Chinmoy, Misra, Aradhana
Spectrum sensing allows cognitive radio systems to detect relevant signals in despite the presence of severe interference. Most of the existing spectrum sensing techniques use a particular signal-noise model with certain assumptions and derive certain detection performance. To deal with this uncertainty, learning based approaches are being adopted and more recently deep learning based tools have become popular. Here, we propose an approach of spectrum sensing which is based on long short term memory (LSTM) which is a critical element of deep learning networks (DLN). Use of LSTM facilitates implicit feature learning from spectrum data. The DLN is trained using several features and the performance of the proposed sensing technique is validated with the help of an empirical testbed setup using Adalm Pluto. The testbed is trained to acquire the primary signal of a real world radio broadcast taking place using FM. Experimental data show that even at low signal to noise ratio, our approach performs well in terms of detection and classification accuracies, as compared to current spectrum sensing methods.
Get used to hearing about machine learnings operations (MLOps) startups – TechCrunch
Welcome to The TechCrunch Exchange, a weekly startups-and-markets newsletter. It's inspired by the daily TechCrunch column where it gets its name. If you aren't in the United States, it's a little hard to explain. In short, certain deficiencies in our policing and judicial systems flared brightly as the week came to a close. So, today's Exchange newsletter will be shorter than intended. Hug the people you love, and everyone else.
Design's new frontier
In the 1960s, the advent of computer-aided design (CAD) sparked a revolution in design. For his PhD thesis in 1963, MIT Professor Ivan Sutherland developed Sketchpad, a game-changing software program that enabled users to draw, move, and resize shapes on a computer. Over the course of the next few decades, CAD software reshaped how everything from consumer products to buildings and airplanes were designed. "CAD was part of the first wave in computing in design. The ability of researchers and practitioners to represent and model designs using computers was a major breakthrough and still is one of the biggest outcomes of design research, in my opinion," says Maria Yang, Gail E. Kendall Professor and director of MIT's Ideation Lab.
Digital Agriculture for Small-Scale Producers
Ranveer Chandra is the managing director of Research for Industry and leads Networking Research at Microsoft Research in Redmond, WA, USA. His research has shipped in multiple Microsoft products, including Xbox, Azure, and Windows. Stewart Collis is senior program officer for Digital Agriculture Solutions at the Bill and Melinda Gates Foundation where he focuses on digital farmer services, smart farming, and digital support systems for small-scale crop and livestock producers in low- and middle-income countries.
Owkin Becomes A Unicorn With $180 Million Investment From Sanofi
Owkin and Sanofi have announced that Owkin is now a unicorn – a startup valued at more than $1 billion – through a new $180 million investment from Sanofi. Sanofi will take a $180 million equity stake and alongside the investment, Owkin and Sanofi will enter a strategic multi-year collaboration to seek out new cancer therapies using AI. The project will focus on four types of cancer including non-small cell lung cancer, triple-negative breast cancer, mesothelioma, and multiple myeloma. They will use Owkin's predictive biomedical AI models to find new biomarkers and therapeutic targets. Owkin will also build prognostic models to predict how a patient will respond to a particular treatment.