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Kai Xi

Publications and source records attributed to Kai Xi.

5 recordsLinked to original sources

Learning Lifted Action Models from Unsupervised Visual Traces

Efficient construction of models capturing the preconditions and effects of actions is essential for applying AI planning in real-world domains. Extensive prior work has explored learning such models from high-level descriptions of state and/or action sequences. In this paper, we tackle a more challenging setting: learning lifted action models from sequences of state images, without action observation. We propose a deep learning framework that jointly learns state prediction, action prediction, and a lifted action model. We also introduce a mixed-integer linear program (MILP) to prevent prediction collapse and self-reinforcing errors among predictions. The MILP takes the predicted states, actions, and action model over a subset of traces and solves for logically consistent states, actions, and action model that are as close as possible to the original predictions. Pseudo-labels extracted from the MILP solution are then used to guide further training. Experiments across multiple domains show that integrating MILP-based correction helps the model escape local optima and converge toward globally consistent solutions.

cs.AI

Implications of Noise in Resistive Memory on Deep Neural Networks for Image Classification

Resistive memory is a promising alternative to SRAM, but is also an inherently unstable device that requires substantial effort to ensure correct read and write operations. To avoid the associated costs in terms of area, time and energy, the present work is concerned with exploring how much noise in memory operations can be tolerated by image classification tasks based on neural networks. We introduce a special noisy operator that mimics the noise in an exemplary resistive memory unit, explore the resilience of convolutional neural networks on the CIFAR-10 classification task, and discuss a couple of countermeasures to improve this resilience.

cs.LG

Ultrahigh Responsivity Photodetectors of Two-dimensional Covalent Organic Frameworks Integrated on Graphene

Two dimensional (2D) materials exhibit superior properties in electronic and optoelectronic fields. The wide demand for high performance optoelectronic devices promotes the exploration of diversified 2D materials. Recently, 2D covalent organic frameworks (COFs) have emerged as next-generation layered materials with predesigned pi electronic skeletons and highly ordered topological structures, which are promising for tailoring their optoelectronic properties. However, COFs are usually produced as solid powders due to anisotropic growth, making them unreliable to integrate into devices. Here, by selecting tetraphenylethylene (TPE) monomers with photoelectric activity, we designed and synthesized photosensitive 2D COFs with highly ordered topologies and grew 2D COFs in situ on graphene to form well ordered COF graphene heterostructures. Ultrasensitive photodetectors were successfully fabricated with the COFETBC TAPT graphene heterostructure and exhibited an excellent overall performance. Moreover, due to the high surface area and the polarity selectivity of COFs, the photosensing properties of the photodetectors can be reversibly regulated by specific target molecules. Our research provides new strategies for building advanced functional devices with programmable material structures and diversified regulation methods, paving the way for a generation of high performance applications in optoelectronics and many other fields.

physics.app-ph

Monte Carlo Predictions of Proton SEE Cross-Sections from Heavy Ion Test Data

The limits of previous methods promote us to design a new approach (named PRESTAGE) to predict proton single event effect (SEE) cross-sections using heavy-ion test data. To more realistically simulate the SEE mechanisms, we adopt Geant4 and the location-dependent strategy to describe the physics processes and the sensitivity of the device. Cross-sections predicted by PRESTAGE for over twenty devices are compared with the measured data. Evidences show that PRESTAGE can calculate not only single event upsets induced by proton indirect ionization, but also direct ionization effects and single event latch-ups. Most of the PRESTAGE calculated results agree with the experimental data within a factor of 2-3.

physics.acc-ph

Single Event Effect Hardness for the Front-end ASICs Applied in BGO Calorimeter of DAMPE Satellite

Dark Matter Particle Explorer (DAMPE) is a Chinese scientific satellite designed for cosmic ray study with a primary scientific goal of indirect search of dark matter particles. As a crucial sub-detector, BGO calorimeter measures the energy spectrum of cosmic rays in the energy range from 5 GeV to 10 TeV. In order to implement high-density front-end electronics (FEE) with the ability to measure 1848 signals from 616 photomultiplier tubes on the strictly constrained satellite platform, two kinds of 32-channel front-end ASICs, VA160 and VATA160, are customized. However, a space mission period of more than 3 years makes single event effect (SEE) a probable threat to reliability. In order to evaluate the SEE sensitivity of the chips and verify the effectiveness of mitigation methods, a series of laser-induced and heavy ion-induced SEE tests were performed. Benefiting from the single event latch-up (SEL) protection circuit for power supply, the triple module redundancy (TMR) technology for the configuration registers and optimized sequential design for data acquisition process, VA160 and VATA160 with the quantity of 54 and 32 respectively have been applied in the flight model of BGO calorimeter with radiation hardness assurance.

physics.ins-det