Performance models are essential for automatic code optimization, enabling compilers to predict the effects of code transformations on performance and guide search for optimal transformations. Building state-of-the-art performance models with deep learning, however, requires vast labeled datasets of random programs – an expensive and time-consuming process, stretching over months. This paper introduces a self-supervised pre-training scheme with autoencoders to reduce the need for labeled data. By pre-training on a large dataset of random programs, the autoencoder learns representations of code and transformations, which are then used to embed programs for the performance model. Implemented in the Tiramisu autoscheduler, our approach improves model accuracy with less data. For example, to achieve a MAPE of 20.72%, the original model requires 18 million data points, whereas our method achieves a similar MAPE of 22.44% with only 3.6 million data points, reducing data requirements by 5×.

MOTIVATION: N4-methylcytosine (4mC) is an essential kind of epigenetic modification that regulates a wide range of biological processes. However, experimental methods for detecting 4mC sites are time-consuming and labor-intensive. As an alternative, computational methods that are capable of automatically identifying 4mC with data analysis techniques become a reasonable option. A major challenge is how to develop effective methods to fully exploit the complex interactions within the DNA sequences to improve the predictive capability. RESULTS: In this work, we propose MSNet-4mC, a lightweight neural network building upon convolutional operations with multi-scale receptive fields to perceive cross-element relationships over both short and long ranges of given DNA sequences. With strong imbalances in the number of candidates in different species in mind, we compute and apply class weights in the cross-entropy loss to balance the training process. Extensive benchmarking experiments show that our method achieves a significant performance improvement and outperforms other state-of-the-art methods. AVAILABILITY AND IMPLEMENTATION: The source code and models are freely available for download at https://github.com/LIU-CT/MSNet-4mC, implemented in Python and supported on Linux and Windows. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Wireless sensor networks (WSNs) can implement complicated tasks through collaboration among multiple sensor nodes. The low-cost sensors in WSNs often generate noisy and even faulty measurements, which will degrade the network performance. Therefore developing collaborative signal processing (CSP) algorithms that has high fault tolerance ability is necessary for the increasingly deployed WSNs. In this study, the authors propose a novel fault tolerant fusion scheme to implement reliable vehicle classification by integrating fault detection and correction with a spatio-temporal fusion structure. Sensor faults are detected at the fusion centre and then the fault detection results are fed back to the local sensors to update subsequent classification results. A Dempster–Shafer theory based fault correction strategy is devised to utilise the fusion centre feedback. Simulation results demonstrate that the proposed scheme ensures more than 95% of the classification results to be correct when no larger than 30% of the sensors are faulty and the scheme achieves improved fault detection rate and false alarm rate than the optimum threshold Bayesian fault detection scheme.

One of the important tasks in sensor networks is classifying moving vehicles. Fusion of large amount of sensor measurements can improve network performance and reduce the consumption of sensor network resource. We study using continuous measurements of multiple sensor nodes to improve the classification performance by spatio-temporal fusion and fault detection. Time series decisions of single sensor node are aggregated to make a reliable classification estimation. A fusion center combines local classification decisions and evaluates the correctness of these decisions. A correctness status is sent back to each sensor node. Based on the status, sensor nodes can adjust their temporal fusion result. Simulation results demonstrate the validity of our method.