128 research outputs found
Bilinear Graph Neural Network with Neighbor Interactions
Graph Neural Network (GNN) is a powerful model to learn representations and
make predictions on graph data. Existing efforts on GNN have largely defined
the graph convolution as a weighted sum of the features of the connected nodes
to form the representation of the target node. Nevertheless, the operation of
weighted sum assumes the neighbor nodes are independent of each other, and
ignores the possible interactions between them. When such interactions exist,
such as the co-occurrence of two neighbor nodes is a strong signal of the
target node's characteristics, existing GNN models may fail to capture the
signal. In this work, we argue the importance of modeling the interactions
between neighbor nodes in GNN. We propose a new graph convolution operator,
which augments the weighted sum with pairwise interactions of the
representations of neighbor nodes. We term this framework as Bilinear Graph
Neural Network (BGNN), which improves GNN representation ability with bilinear
interactions between neighbor nodes. In particular, we specify two BGNN models
named BGCN and BGAT, based on the well-known GCN and GAT, respectively.
Empirical results on three public benchmarks of semi-supervised node
classification verify the effectiveness of BGNN -- BGCN (BGAT) outperforms GCN
(GAT) by 1.6% (1.5%) in classification accuracy.Codes are available at:
https://github.com/zhuhm1996/bgnn.Comment: Accepted by IJCAI 2020. SOLE copyright holder is IJCAI (International
Joint Conferences on Artificial Intelligence), all rights reserve
On the Calibration of Large Language Models and Alignment
As large language models attract increasing attention and find widespread
application, concurrent challenges of reliability also arise at the same time.
Confidence calibration, an effective analysis method for gauging the
reliability of deep models, serves as a crucial tool for assessing and
improving their reliability. However, such investigation has been comparatively
underexplored. In this work, we conduct a systematic examination of the
calibration of aligned language models throughout the entire construction
process, including pretraining and alignment training. At each stage, we
investigate how different training settings, such as parameter scales and
training data, affect model calibration. To thoroughly assess model
calibration, we evaluate models on three most concerned aspects: generation,
factuality and understanding. Our work sheds light on whether popular LLMs are
well-calibrated and how the training process influences model calibration.Comment: to be published in findings of EMNLP-202
Minimum-Energy Bivariate Wavelet Frame with Arbitrary Dilation Matrix
In order to characterize the bivariate signals, minimum-energy bivariate wavelet frames with arbitrary dilation matrix are studied, which are based on superiority of the minimum-energy frame and the significant properties of bivariate wavelet. Firstly, the concept of minimum-energy bivariate wavelet frame is defined, and its equivalent characterizations and a necessary condition are presented. Secondly, based on polyphase form of symbol functions of scaling function and wavelet function, two sufficient conditions and an explicit constructed method are given. Finally, the decomposition algorithm, reconstruction algorithm, and numerical examples are designed
Epidemiology and associations with climatic conditions of Mycoplasma pneumoniae and Chlamydophila pneumoniae infections among Chinese children hospitalized with acute respiratory infections
BACKGROUND: The incidence of severe acute respiratory tract infections in children caused by Mycoplasma pneumoniae (syn. Schizoplasma pneumoniae) and Chlamydophila pneumoniae (formerly Chlamydia pneumoniae) varies greatly from year to year and place to place around the world. This study investigated the epidemiology of M. pneumoniae and C. pneumoniae infections among children hospitalized with acute respiratory infections in Suzhou, China in the year 2006, and associations between incidence rates and climatic conditions. METHODS: Nasopharyngeal aspirates obtained from 1598 patients (aged 26.4 ± 28.3 months; range, 1 month to 13 years) were analyzed with real-time PCR and ELISA. Meteorological data were obtained from the weather bureau. RESULTS: About 18.5% of patients were infected with M. pneumoniae and, C. pneumoniae, or both. Isolated M. pneumoniae infection was positively correlated with increasing age (χ(2) = 34.76, P < 0.0001). Incidence of M. pneumoniae infection was seasonal with a peak in summer (P < 0.0001) and minimum in winter (P = 0.0001), whereas C. pneumoniae infection was low only in autumn (P = 0.02). Monthly mean temperature was strongly correlated with the incidence of M. pneumoniae infection (r = 0.825, P = 0.001). CONCLUSIONS: M. pneumoniae and C. pneumoniae are important infectious agents in hospitalized children with acute respiratory tract infections. M. pneumoniae infection showed a strong direct correlation with environmental temperature
AI-Oriented Two-Phase Multi-Factor Authentication in SAGINs: Prospects and Challenges
Space-air-ground integrated networks (SAGINs), which have emerged as an
expansion of terrestrial networks, provide flexible access, ubiquitous
coverage, high-capacity backhaul, and emergency/disaster recovery for mobile
users (MUs). While the massive benefits brought by SAGIN may improve the
quality of service, unauthorized access to SAGIN entities is potentially
dangerous. At present, conventional crypto-based authentication is facing
challenges, such as the inability to provide continuous and transparent
protection for MUs. In this article, we propose an AI-oriented two-phase
multi-factor authentication scheme (ATMAS) by introducing intelligence to
authentication. The satellite and network control center collaborate on
continuous authentication, while unique spatial-temporal features, including
service features and geographic features, are utilized to enhance the system
security. Our further security analysis and performance evaluations show that
ATMAS has proper security characteristics which can meet various security
requirements. Moreover, we shed light on lightweight and efficient
authentication mechanism design through a proper combination of
spatial-temporal factors.Comment: Accepted by IEEE Consumer Electronics Magazin
Select2Col: Leveraging Spatial-Temporal Importance of Semantic Information for Efficient Collaborative Perception
Collaboration by leveraging the shared semantic information plays a crucial
role in overcoming the perception capability limitations of isolated agents.
However, existing collaborative perception methods tend to focus solely on the
spatial features of semantic information, while neglecting the importance of
the temporal dimension. Consequently, the potential benefits of collaboration
remain underutilized. In this article, we propose Select2Col, a novel
collaborative perception framework that takes into account the
{s}patial-t{e}mpora{l} importanc{e} of semanti{c} informa{t}ion. Within the
Select2Col, we develop a collaborator selection method that utilizes a
lightweight graph neural network (GNN) to estimate the importance of semantic
information (IoSI) in enhancing perception performance, thereby identifying
contributive collaborators while excluding those that bring negative impact.
Moreover, we present a semantic information fusion algorithm called HPHA
(historical prior hybrid attention), which integrates multi-scale attention and
short-term attention modules to capture the IoSI in feature representation from
the spatial and temporal dimensions respectively, and assigns IoSI-consistent
weights for efficient fusion of information from selected collaborators.
Extensive experiments on two open datasets demonstrate that our proposed
Select2Col significantly improves the perception performance compared to
state-of-the-art approaches. The code associated with this research is publicly
available at https://github.com/huangqzj/Select2Col/
Simulation of External Ion Injection, Cooling and Extraction Processes with SIMION 6.0 for the Ion Trap/Reflectron Time-of-flight Mass Spectrometer
In this work we have developed a PC-based simulation to study ion injection, cooling and extraction processes for multiple ions in an ion trap/reflectron time-of-flight (IT/reTOF) system. This simulation is based upon SIMION 6.0 with user written programs in which a 3D collision model is used to describe ion – buffer gas molecule interactions. The results of various simulations describing the relation between the trapping efficiency for external injection of ions into the trap and the RF phase, and the effects of initial kinetic energy and ramp-up rate on dynamic trapping of externally produced ions are discussed. Further, single-pulsing and bipolar-pulsing schemes for ejecting ions from the trap are examined. The simulations show that bipolar pulsing can markedly improve the resolution. In the bipolar ejection mode the relation between resolution and the extraction voltages and RF ramp-off rate are studied. © 1997 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35068/1/54_ftp.pd
Increased concentrations of soluble B7-H3 and interleukin 36 in bronchoalveolar lavage fluid of Children with Mycoplasma pneumoniae pneumonia
Supporting data. (XLS 58 kb
Accelerate Presolve in Large-Scale Linear Programming via Reinforcement Learning
Large-scale LP problems from industry usually contain much redundancy that
severely hurts the efficiency and reliability of solving LPs, making presolve
(i.e., the problem simplification module) one of the most critical components
in modern LP solvers. However, how to design high-quality presolve routines --
that is, the program determining (P1) which presolvers to select, (P2) in what
order to execute, and (P3) when to stop -- remains a highly challenging task
due to the extensive requirements on expert knowledge and the large search
space. Due to the sequential decision property of the task and the lack of
expert demonstrations, we propose a simple and efficient reinforcement learning
(RL) framework -- namely, reinforcement learning for presolve (RL4Presolve) --
to tackle (P1)-(P3) simultaneously. Specifically, we formulate the routine
design task as a Markov decision process and propose an RL framework with
adaptive action sequences to generate high-quality presolve routines
efficiently. Note that adaptive action sequences help learn complex behaviors
efficiently and adapt to various benchmarks. Experiments on two solvers
(open-source and commercial) and eight benchmarks (real-world and synthetic)
demonstrate that RL4Presolve significantly and consistently improves the
efficiency of solving large-scale LPs, especially on benchmarks from industry.
Furthermore, we optimize the hard-coded presolve routines in LP solvers by
extracting rules from learned policies for simple and efficient deployment to
Huawei's supply chain. The results show encouraging economic and academic
potential for incorporating machine learning to modern solvers
- …