127 research outputs found
An Empirical Comparison of Various Online Binary Classification Algorithms
Honors (Bachelor's)StatisticsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/112099/1/hxinyan.pd
AutoFi: Towards Automatic WiFi Human Sensing via Geometric Self-Supervised Learning
WiFi sensing technology has shown superiority in smart homes among various
sensors for its cost-effective and privacy-preserving merits. It is empowered
by Channel State Information (CSI) extracted from WiFi signals and advanced
machine learning models to analyze motion patterns in CSI. Many learning-based
models have been proposed for kinds of applications, but they severely suffer
from environmental dependency. Though domain adaptation methods have been
proposed to tackle this issue, it is not practical to collect high-quality,
well-segmented and balanced CSI samples in a new environment for adaptation
algorithms, but randomly-captured CSI samples can be easily collected.
{\color{black}In this paper, we firstly explore how to learn a robust model
from these low-quality CSI samples, and propose AutoFi, an annotation-efficient
WiFi sensing model based on a novel geometric self-supervised learning
algorithm.} The AutoFi fully utilizes unlabeled low-quality CSI samples that
are captured randomly, and then transfers the knowledge to specific tasks
defined by users, which is the first work to achieve cross-task transfer in
WiFi sensing. The AutoFi is implemented on a pair of Atheros WiFi APs for
evaluation. The AutoFi transfers knowledge from randomly collected CSI samples
into human gait recognition and achieves state-of-the-art performance.
Furthermore, we simulate cross-task transfer using public datasets to further
demonstrate its capacity for cross-task learning. For the UT-HAR and Widar
datasets, the AutoFi achieves satisfactory results on activity recognition and
gesture recognition without any prior training. We believe that the AutoFi
takes a huge step toward automatic WiFi sensing without any developer
engagement.Comment: The paper has been accepted by IEEE Internet of Things Journa
Estimation of the Incubation Period and the Serial Interval of COVID-19 in Chongqing, China
In December 2019, the initial case of COVID-19's disease appeared in Wuhan, Hubei Province, China. But it soon caused an outbreak in Chongqing as well. Reasonable estimates for the incubation period distribution and the serial interval distribution would provide timely information to guide intervention policy for the government of Chongqing. We collect individual information from Chongqing Center for Disease Control and Prevention(CQCDC). We use doubly interval-censored data to estimate the incubation period and the serial interval for confirmed cases exposed to COVID-19 during incubation period,the mean incubation period is estimated to be 7.5(6.6-8.6,95% CI) days and the mean serial interval is estimated to be 6.1 (5.0-7.5,95% CI) days. The analysis result show that COVID-19 could spread in the incubation period,which may complicate quarantine work. The implementation of control measures is indispensable in reducing the spread of asymptomatic incubation period in high-risk population
Convolutional Embedding for Edit Distance
Edit-distance-based string similarity search has many applications such as
spell correction, data de-duplication, and sequence alignment. However,
computing edit distance is known to have high complexity, which makes string
similarity search challenging for large datasets. In this paper, we propose a
deep learning pipeline (called CNN-ED) that embeds edit distance into Euclidean
distance for fast approximate similarity search. A convolutional neural network
(CNN) is used to generate fixed-length vector embeddings for a dataset of
strings and the loss function is a combination of the triplet loss and the
approximation error. To justify our choice of using CNN instead of other
structures (e.g., RNN) as the model, theoretical analysis is conducted to show
that some basic operations in our CNN model preserve edit distance.
Experimental results show that CNN-ED outperforms data-independent CGK
embedding and RNN-based GRU embedding in terms of both accuracy and efficiency
by a large margin. We also show that string similarity search can be
significantly accelerated using CNN-based embeddings, sometimes by orders of
magnitude.Comment: Accepted by the 43rd International ACM SIGIR Conference on Research
and Development in Information Retrieval, 202
Mitigating Large Language Model Hallucinations via Autonomous Knowledge Graph-based Retrofitting
Incorporating factual knowledge in knowledge graph is regarded as a promising
approach for mitigating the hallucination of large language models (LLMs).
Existing methods usually only use the user's input to query the knowledge
graph, thus failing to address the factual hallucination generated by LLMs
during its reasoning process. To address this problem, this paper proposes
Knowledge Graph-based Retrofitting (KGR), a new framework that incorporates
LLMs with KGs to mitigate factual hallucination during the reasoning process by
retrofitting the initial draft responses of LLMs based on the factual knowledge
stored in KGs. Specifically, KGR leverages LLMs to extract, select, validate,
and retrofit factual statements within the model-generated responses, which
enables an autonomous knowledge verifying and refining procedure without any
additional manual efforts. Experiments show that KGR can significantly improve
the performance of LLMs on factual QA benchmarks especially when involving
complex reasoning processes, which demonstrates the necessity and effectiveness
of KGR in mitigating hallucination and enhancing the reliability of LLMs
Early-Life Intervention Using Exogenous Fecal Microbiota Alleviates Gut Injury and Reduce Inflammation Caused by Weaning Stress in Piglets
Fecal microbiota transplantation (FMT) could shape the structure of intestinal microbiota in animals. This study was conducted to explore the changes that happen in the structure and function of microbiota caused by weaning stress, and whether early-life FMT could alleviate weaning stress through modifying intestinal microbiota in weaned piglets. Diarrheal (D) and healthy (H) weaned piglets were observed, and in the same farm, a total of nine litters newborn piglets were randomly allocated to three groups: sucking normally (S), weaned at 21 d (W), and early-life FMT + weaned at 21 d (FW). The results demonstrated that differences of fecal microbiota existed in group D and H. Early-life FMT significantly decreased diarrhea incidence of weaned piglets. Intestinal morphology and integrity were improved in the FW group. Both ZO-1 and occludin (tight junction proteins) of jejunum were greatly enhanced, while the zonulin expression was significantly down-regulated through early-life FMT. The expression of IL-6 and TNF-α (intestinal mucosal inflammatory cytokines) were down-regulated, while IL-10 (anti-inflammatory cytokines) was up-regulated by early-life FMT. In addition, early-life FMT increased the variety of the intestinal microbial population and the relative amounts of some beneficial bacteria such as Spirochaetes, Akkermansia, and Alistipes. Functional alteration of the intestinal microbiota revealed that lipid biosynthesis and aminoacyl-tRNA biosynthesis were enriched in the FW group. These findings suggested that alteration of the microbiota network caused by weaning stress induced diarrhea, and early-life FMT alleviated weaning stress in piglets, which was characterized by decreased diarrhea incidence, improved intestinal morphology, reduced intestinal inflammation, and modified intestinal bacterial composition and function
SenseFi: A library and benchmark on deep-learning-empowered WiFi human sensing
Over the recent years, WiFi sensing has been rapidly developed for privacy-preserving, ubiquitous human-sensing applications, enabled by signal processing and deep-learning methods. However, a comprehensive public benchmark for deep learning in WiFi sensing, similar to that available for visual recognition, does not yet exist. In this article, we review recent progress in topics ranging from WiFi hardware platforms to sensing algorithms and propose a new library with a comprehensive benchmark, SenseFi. On this basis, we evaluate various deep-learning models in terms of distinct sensing tasks, WiFi platforms, recognition accuracy, model size, computational complexity, and feature transferability. Extensive experiments are performed whose results provide valuable insights into model design, learning strategy, and training techniques for real-world applications. In summary, SenseFi is a comprehensive benchmark with an open-source library for deep learning in WiFi sensing research that offers researchers a convenient tool to validate learning-based WiFi-sensing methods on multiple datasets and platforms.Nanyang Technological UniversityPublished versionThis research is supported by NTU Presidential Postdoctoral Fellowship, ‘‘Adaptive Multi-modal Learning for Robust Sensing and Recognition in Smart Cities’’ project fund (020977-00001), at the Nanyang Technological University, Singapore
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