500 research outputs found
Grid multi-category response logistic models.
BackgroundMulti-category response models are very important complements to binary logistic models in medical decision-making. Decomposing model construction by aggregating computation developed at different sites is necessary when data cannot be moved outside institutions due to privacy or other concerns. Such decomposition makes it possible to conduct grid computing to protect the privacy of individual observations.MethodsThis paper proposes two grid multi-category response models for ordinal and multinomial logistic regressions. Grid computation to test model assumptions is also developed for these two types of models. In addition, we present grid methods for goodness-of-fit assessment and for classification performance evaluation.ResultsSimulation results show that the grid models produce the same results as those obtained from corresponding centralized models, demonstrating that it is possible to build models using multi-center data without losing accuracy or transmitting observation-level data. Two real data sets are used to evaluate the performance of our proposed grid models.ConclusionsThe grid fitting method offers a practical solution for resolving privacy and other issues caused by pooling all data in a central site. The proposed method is applicable for various likelihood estimation problems, including other generalized linear models
Symbol-LLM: Leverage Language Models for Symbolic System in Visual Human Activity Reasoning
Human reasoning can be understood as a cooperation between the intuitive,
associative "System-1" and the deliberative, logical "System-2". For existing
System-1-like methods in visual activity understanding, it is crucial to
integrate System-2 processing to improve explainability, generalization, and
data efficiency. One possible path of activity reasoning is building a symbolic
system composed of symbols and rules, where one rule connects multiple symbols,
implying human knowledge and reasoning abilities. Previous methods have made
progress, but are defective with limited symbols from handcraft and limited
rules from visual-based annotations, failing to cover the complex patterns of
activities and lacking compositional generalization. To overcome the defects,
we propose a new symbolic system with two ideal important properties:
broad-coverage symbols and rational rules. Collecting massive human knowledge
via manual annotations is expensive to instantiate this symbolic system.
Instead, we leverage the recent advancement of LLMs (Large Language Models) as
an approximation of the two ideal properties, i.e., Symbols from Large Language
Models (Symbol-LLM). Then, given an image, visual contents from the images are
extracted and checked as symbols and activity semantics are reasoned out based
on rules via fuzzy logic calculation. Our method shows superiority in extensive
activity understanding tasks. Code and data are available at
https://mvig-rhos.com/symbol_llm.Comment: Accepted by NeurIPS 202
Mining Cross-Person Cues for Body-Part Interactiveness Learning in HOI Detection
Human-Object Interaction (HOI) detection plays a crucial role in activity
understanding. Though significant progress has been made, interactiveness
learning remains a challenging problem in HOI detection: existing methods
usually generate redundant negative H-O pair proposals and fail to effectively
extract interactive pairs. Though interactiveness has been studied in both
whole body- and part- level and facilitates the H-O pairing, previous works
only focus on the target person once (i.e., in a local perspective) and
overlook the information of the other persons. In this paper, we argue that
comparing body-parts of multi-person simultaneously can afford us more useful
and supplementary interactiveness cues. That said, to learn body-part
interactiveness from a global perspective: when classifying a target person's
body-part interactiveness, visual cues are explored not only from
herself/himself but also from other persons in the image. We construct
body-part saliency maps based on self-attention to mine cross-person
informative cues and learn the holistic relationships between all the
body-parts. We evaluate the proposed method on widely-used benchmarks HICO-DET
and V-COCO. With our new perspective, the holistic global-local body-part
interactiveness learning achieves significant improvements over
state-of-the-art. Our code is available at
https://github.com/enlighten0707/Body-Part-Map-for-Interactiveness.Comment: To appear in ECCV 202
OPR-Miner: Order-preserving rule mining for time series
Discovering frequent trends in time series is a critical task in data mining.
Recently, order-preserving matching was proposed to find all occurrences of a
pattern in a time series, where the pattern is a relative order (regarded as a
trend) and an occurrence is a sub-time series whose relative order coincides
with the pattern. Inspired by the order-preserving matching, the existing
order-preserving pattern (OPP) mining algorithm employs order-preserving
matching to calculate the support, which leads to low efficiency. To address
this deficiency, this paper proposes an algorithm called efficient frequent OPP
miner (EFO-Miner) to find all frequent OPPs. EFO-Miner is composed of four
parts: a pattern fusion strategy to generate candidate patterns, a matching
process for the results of sub-patterns to calculate the support of
super-patterns, a screening strategy to dynamically reduce the size of prefix
and suffix arrays, and a pruning strategy to further dynamically prune
candidate patterns. Moreover, this paper explores the order-preserving rule
(OPR) mining and proposes an algorithm called OPR-Miner to discover strong
rules from all frequent OPPs using EFO-Miner. Experimental results verify that
OPR-Miner gives better performance than other competitive algorithms. More
importantly, clustering and classification experiments further validate that
OPR-Miner achieves good performance
Rifamycin Resistance in Clostridium difficile Is Generally Associated with a Low Fitness Burden
We characterized clinically occurring and novel mutations in the β subunit of RNA polymerase in Clostridium difficile (CdRpoB), conferring rifamycin (including rifaximin) resistance. The Arg(505)Lys substitution did not impose an in vitro fitness cost, which may be one reason for its dominance among rifamycin-resistant clinical isolates. These observations were supported through the structural modeling of CdRpoB. In general, most mutations lacked in vitro fitness costs, suggesting that rifamycin resistance may in some cases persist in the clinic
An innovative information fusion method with adaptive Kalman filter for integrated INS/GPS navigation of autonomous vehicles
Information fusion method of INS/GPS navigation system based on filtering technology is a research focus at present. In order to improve the precision of navigation information, a navigation technology based on Adaptive Kalman Filter with attenuation factor is proposed to restrain noise in this paper. The algorithm continuously updates the measurement noise variance and processes noise variance of the system by collecting the estimated and measured values, and this method can suppress white noise. Because a measured value closer to the current time would more accurately reflect the characteristics of the noise, an attenuation factor is introduced to increase the weight of the current value, in order to deal with the noise variance caused by environment disturbance. To validate the effectiveness of the proposed algorithm, a series of road tests are carried out in urban environment. The GPS and IMU data of the experiments were collected and processed by dSPACE and MATLAB/Simulink. Based on the test results, the accuracy of the proposed algorithm is 20% higher than that of a traditional Adaptive Kalman Filter. It also shows that the precision of the integrated navigation can be improved due to the reduction of the influence of environment noise
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