28 research outputs found
Tailoring the mechanical properties of 3D microstructures: a deep learning and genetic algorithm inverse optimization framework
Materials-by-design has been historically challenging due to complex
process-microstructure-property relations. Conventional analytical or
simulation-based approaches suffer from low accuracy or long computational time
and poor transferability, further limiting their applications in solving the
inverse material design problem. Here, we establish a deep learning and genetic
algorithm framework that integrates forward prediction and inverse exploration.
This framework provides an end-to-end solution to achieve application-specific
mechanical properties by microstructure optimization. In this study, we select
the widely used Ti-6Al-4V to demonstrate the effectiveness of this framework by
tailoring its microstructure and achieving various yield strength and elastic
modulus across a large design space, while minimizing the stress concentration
factor. Compared with conventional methods, our framework is efficient,
versatile, and readily transferrable to other materials and properties. Paired
with additive manufacturing's potential in controlling local microstructural
features, our method has far-reaching potential for accelerating the
development of application-specific, high-performing materials.Comment: 19 pages, 5 figure
Maat: Performance Metric Anomaly Anticipation for Cloud Services with Conditional Diffusion
Ensuring the reliability and user satisfaction of cloud services necessitates
prompt anomaly detection followed by diagnosis.
Existing techniques for anomaly detection focus solely on real-time
detection, meaning that anomaly alerts are issued as soon as anomalies occur.
However, anomalies can propagate and escalate into failures, making
faster-than-real-time anomaly detection highly desirable for expediting
downstream analysis and intervention.
This paper proposes Maat, the first work to address anomaly anticipation of
performance metrics in cloud services.
Maat adopts a novel two-stage paradigm for anomaly anticipation, consisting
of metric forecasting and anomaly detection on forecasts.
The metric forecasting stage employs a conditional denoising diffusion model
to enable multi-step forecasting in an auto-regressive manner.
The detection stage extracts anomaly-indicating features based on domain
knowledge and applies isolation forest with incremental learning to detect
upcoming anomalies.
Thus, our method can uncover anomalies that better conform to human
expertise.
Evaluation on three publicly available datasets demonstrates that Maat can
anticipate anomalies faster than real-time comparatively or more effectively
compared with state-of-the-art real-time anomaly detectors.
We also present cases highlighting Maat's success in forecasting abnormal
metrics and discovering anomalies.Comment: This paper has been accepted by the Research track of the 38th
IEEE/ACM International Conference on Automated Software Engineering (ASE
2023
Heterogeneous Anomaly Detection for Software Systems via Semi-supervised Cross-modal Attention
Prompt and accurate detection of system anomalies is essential to ensure the
reliability of software systems. Unlike manual efforts that exploit all
available run-time information, existing approaches usually leverage only a
single type of monitoring data (often logs or metrics) or fail to make
effective use of the joint information among different types of data.
Consequently, many false predictions occur. To better understand the
manifestations of system anomalies, we conduct a systematical study on a large
amount of heterogeneous data, i.e., logs and metrics. Our study demonstrates
that logs and metrics can manifest system anomalies collaboratively and
complementarily, and neither of them only is sufficient. Thus, integrating
heterogeneous data can help recover the complete picture of a system's health
status. In this context, we propose Hades, the first end-to-end semi-supervised
approach to effectively identify system anomalies based on heterogeneous data.
Our approach employs a hierarchical architecture to learn a global
representation of the system status by fusing log semantics and metric
patterns. It captures discriminative features and meaningful interactions from
heterogeneous data via a cross-modal attention module, trained in a
semi-supervised manner. We evaluate Hades extensively on large-scale simulated
data and datasets from Huawei Cloud. The experimental results present the
effectiveness of our model in detecting system anomalies. We also release the
code and the annotated dataset for replication and future research.Comment: In Proceedings of the 2023 IEEE/ACM 45th International Conference on
Software Engineering (ICSE). arXiv admin note: substantial text overlap with
arXiv:2207.0291
An Adaptive Resilience Testing Framework for Microservice Systems
Resilience testing, which measures the ability to minimize service
degradation caused by unexpected failures, is crucial for microservice systems.
The current practice for resilience testing relies on manually defining rules
for different microservice systems. Due to the diverse business logic of
microservices, there are no one-size-fits-all microservice resilience testing
rules. As the quantity and dynamic of microservices and failures largely
increase, manual configuration exhibits its scalability and adaptivity issues.
To overcome the two issues, we empirically compare the impacts of common
failures in the resilient and unresilient deployments of a benchmark
microservice system. Our study demonstrates that the resilient deployment can
block the propagation of degradation from system performance metrics (e.g.,
memory usage) to business metrics (e.g., response latency). In this paper, we
propose AVERT, the first AdaptiVE Resilience Testing framework for microservice
systems. AVERT first injects failures into microservices and collects available
monitoring metrics. Then AVERT ranks all the monitoring metrics according to
their contributions to the overall service degradation caused by the injected
failures. Lastly, AVERT produces a resilience index by how much the degradation
in system performance metrics propagates to the degradation in business
metrics. The higher the degradation propagation, the lower the resilience of
the microservice system. We evaluate AVERT on two open-source benchmark
microservice systems. The experimental results show that AVERT can accurately
and efficiently test the resilience of microservice systems
Privacy-preserving design of graph neural networks with applications to vertical federated learning
The paradigm of vertical federated learning (VFL), where institutions
collaboratively train machine learning models via combining each other's local
feature or label information, has achieved great success in applications to
financial risk management (FRM). The surging developments of graph
representation learning (GRL) have opened up new opportunities for FRM
applications under FL via efficiently utilizing the graph-structured data
generated from underlying transaction networks. Meanwhile, transaction
information is often considered highly sensitive. To prevent data leakage
during training, it is critical to develop FL protocols with formal privacy
guarantees. In this paper, we present an end-to-end GRL framework in the VFL
setting called VESPER, which is built upon a general privatization scheme
termed perturbed message passing (PMP) that allows the privatization of many
popular graph neural architectures.Based on PMP, we discuss the strengths and
weaknesses of specific design choices of concrete graph neural architectures
and provide solutions and improvements for both dense and sparse graphs.
Extensive empirical evaluations over both public datasets and an industry
dataset demonstrate that VESPER is capable of training high-performance GNN
models over both sparse and dense graphs under reasonable privacy budgets
CPIA Dataset: A Comprehensive Pathological Image Analysis Dataset for Self-supervised Learning Pre-training
Pathological image analysis is a crucial field in computer-aided diagnosis,
where deep learning is widely applied. Transfer learning using pre-trained
models initialized on natural images has effectively improved the downstream
pathological performance. However, the lack of sophisticated domain-specific
pathological initialization hinders their potential. Self-supervised learning
(SSL) enables pre-training without sample-level labels, which has great
potential to overcome the challenge of expensive annotations. Thus, studies
focusing on pathological SSL pre-training call for a comprehensive and
standardized dataset, similar to the ImageNet in computer vision. This paper
presents the comprehensive pathological image analysis (CPIA) dataset, a
large-scale SSL pre-training dataset combining 103 open-source datasets with
extensive standardization. The CPIA dataset contains 21,427,877 standardized
images, covering over 48 organs/tissues and about 100 kinds of diseases, which
includes two main data types: whole slide images (WSIs) and characteristic
regions of interest (ROIs). A four-scale WSI standardization process is
proposed based on the uniform resolution in microns per pixel (MPP), while the
ROIs are divided into three scales artificially. This multi-scale dataset is
built with the diagnosis habits under the supervision of experienced senior
pathologists. The CPIA dataset facilitates a comprehensive pathological
understanding and enables pattern discovery explorations. Additionally, to
launch the CPIA dataset, several state-of-the-art (SOTA) baselines of SSL
pre-training and downstream evaluation are specially conducted. The CPIA
dataset along with baselines is available at
https://github.com/zhanglab2021/CPIA_Dataset
Effects of the Chinese herbal formula San-Huang Gu-Ben Zhi-Ke treatment on stable chronic obstructive pulmonary disease: a randomized, double-blind, placebo-controlled trial
Objective: The aim of this study was to evaluate the efficacy and safety of the Chinese herbal formula San-Huang Gu-Ben Zhi-Ke (SHGBZK) as a treatment for patients with stable chronic obstructive pulmonary disease (COPD) diagnosed with lung-spleen Qi deficiency.Method: A randomized, double-blind, placebo-controlled trial was designed. 98 adults aged between 40 and 80 years with stable COPD diagnosed with lung-spleen Qi deficiency were included. All participants received basic treatment for COPD. Patients in the experimental group took SHGBZK, while the control group took placebo. The primary outcome was the frequency of acute exacerbation. The secondary outcomes were lung function, symptom score, exercise capacity and quality of life.Results: Of 98 patients who underwent randomization, 50 patients in the SHGBZK group and 48 in the placebo group were included in the full analysis set. After 24-week therapy and 28-week follow-up, patients in treatment group had significant improvements in symptom, exercise capacity and quality of life. After Subgroup analysis, the frequency of acute exacerbation in patients with a COPD Assessment Test (CAT) score of at least 10 or a modified Medical Research Council (mMRC) score of at least 2 was significantly lower in the SHGBZK group than in the placebo group. Lung function in patients with frequent exacerbation was significantly higher in the SHGBZK group than in the placebo group. The incidence of adverse events was generally similar in the two groups.Conclusion: SHGBZK had beneficial effects on symptom, exercise capacity and quality of life in stable COPD patients. SHGBZK also had the potential to reduce the frequency of exacerbation and improve lung function in specific groups of COPD patients.Clinical Trial Registration:https://www.chictr.org.cn/showproj.html?proj=26933, identifier ChiCTR180001634
Nodal and Nematic Superconducting Phases in NbSe Monolayers from Competing Superconducting Channels
Transition metal dichalcogenides like 2H-NbSe in their two-dimensional (2D) form exhibit Ising superconductivity with the quasiparticle spins are firmly pinned in the direction perpendicular to the basal plane. This enables them to withstand exceptionally high magnetic fields beyond the Pauli limit for superconductivity. Using field-angle-resolved magnetoresistance experiments for fields rotated in the basal plane we investigate the field-angle dependence of the upper critical field (Hc), which directly reflects the symmetry of the superconducting order parameter. We observe a six-fold nodal symmetry superposed on a two-fold symmetry. This agrees with theoretical predictions of a nodal topological superconducting phase near Hc, together with a nematic superconducting state. We demonstrate that in NbSe such unconventional superconducting states can arise from the presence of several competing superconducting channels