2,161 Hits in 2.4 sec

PointMixup: Augmentation for Point Clouds [article]

Yunlu Chen, Vincent Tao Hu, Efstratios Gavves, Thomas Mensink, Pascal Mettes, Pengwan Yang, Cees G.M. Snoek
2020 arXiv   pre-print
This paper introduces data augmentation for point clouds by interpolation between examples. Data augmentation by interpolation has shown to be a simple and effective approach in the image domain. Such a mixup is however not directly transferable to point clouds, as we do not have a one-to-one correspondence between the points of two different objects. In this paper, we define data augmentation between point clouds as a shortest path linear interpolation. To that end, we introduce PointMixup, an
more » ... interpolation method that generates new examples through an optimal assignment of the path function between two point clouds. We prove that our PointMixup finds the shortest path between two point clouds and that the interpolation is assignment invariant and linear. With the definition of interpolation, PointMixup allows to introduce strong interpolation-based regularizers such as mixup and manifold mixup to the point cloud domain. Experimentally, we show the potential of PointMixup for point cloud classification, especially when examples are scarce, as well as increased robustness to noise and geometric transformations to points. The code for PointMixup and the experimental details are publicly available.
arXiv:2008.06374v1 fatcat:73nwb5vqazet3b2k2a5jlxastm

Localizing the Common Action Among a Few Videos [article]

Pengwan Yang, Vincent Tao Hu, Pascal Mettes, Cees G. M. Snoek
2020 arXiv   pre-print
[36] and Hu et al. [16] further relax the labeling constraint by only requiring a few examples to contain a common object, without the strict need to know their class name. Hu et al.  ...  [10] and to Hu et al. [16] , which focuses on few-shot common object detection. We evaluate on the same setting as Feng Overlap threshold 0.5 0.6 0.7 0.8 0.9 0.5:0.9 Common instance Hu et al.  ... 
arXiv:2008.05826v2 fatcat:wyybbq3dtnd6dd3cn272ytqnca

Mining Likely Properties of Access Control Policies via Association Rule Mining [chapter]

JeeHyun Hwang, Tao Xie, Vincent Hu, Mine Altunay
2010 Lecture Notes in Computer Science  
Access control mechanisms are used to control which principals (such as users or processes) have access to which resources based on access control policies. To ensure the correctness of access control policies, policy authors conduct policy verification to check whether certain properties are satisfied by a policy. However, these properties are often not written in practice. To facilitate property verification, we present an approach that automatically mines likely properties from a policy via
more » ... he technique of association rule mining. In our approach, mined likely properties may not be true for all the policy behaviors but are true for most of the policy behaviors. The policy behaviors that do not satisfy likely properties could be faulty. Therefore, our approach then conducts likelyproperty verification to produce counterexamples, which are used to help policy authors identify faulty rules in the policy. To show the effectiveness of our approach, we conduct evaluation on four XACML policies. Our evaluation results show that our approach achieves more than 30% higher fault-detection capability than that of an existing approach. Our approach includes additional techniques such as basic and prioritization techniques that help reduce a significant percentage of counterexamples for inspection compared to the existing approach.
doi:10.1007/978-3-642-13739-6_13 fatcat:repoducrpjf7ze6awmvgq6dcqi

Property Verification for Generic Access Control Models

Vincent C. Hu, D. Richard Kuhn, Tao Xie
2008 2008 IEEE/IFIP International Conference on Embedded and Ubiquitous Computing  
doi:10.1109/euc.2008.22 dblp:conf/euc/HuKX08 fatcat:cgauvgs74jhtfk75kfwpdyaewa

Assessing Quality of Policy Properties in Verification of Access Control Policies

Evan Martin, JeeHyun Hwang, Tao Xie, Vincent Hu
2008 2008 Annual Computer Security Applications Conference (ACSAC)  
Access control policies are often specified in declarative languages. In this paper, we propose a novel approach, called mutation verification, to assess the quality of properties specified for a policy and, in doing so, the quality of the verification itself. In our approach, given a policy and a set of properties, we first mutate the policy to generate various mutant policies, each with a single seeded fault. We then verify whether the properties hold for each mutant policy. If the properties
more » ... still hold for a given mutant policy, then the quality of these properties is determined to be insufficient in guarding against the seeded fault, indicating that more properties are needed to augment the existing set of properties to provide higher confidence of the policy correctness. We have implemented Mutaver, a mutation verification tool for XACML, and applied it to policies and properties from a real-world software system.
doi:10.1109/acsac.2008.48 dblp:conf/acsac/MartinHXH08 fatcat:dippufpynzcgxkyaf6ann4o6pq

ACPT: A Tool for Modeling and Verifying Access Control Policies

JeeHyun Hwang, Tao Xie, Vincent Hu, Mine Altunay
2010 2010 IEEE International Symposium on Policies for Distributed Systems and Networks  
Access control mechanisms are a widely adopted technology for information security. Since access decisions (i.e., permit or deny) on requests are dependent on access control policies, ensuring the correct modeling and implementation of access control policies is crucial for adopting access control mechanisms. To address this issue, we develop a tool, called ACPT (Access Control Policy Testing), that helps to model and implement policies correctly during policy modeling, implementation, and verification.
doi:10.1109/policy.2010.22 dblp:conf/policy/HwangXHA10 fatcat:67ae77ddw5bbzgud5kr4qjhjqe

Self-supervised Video Representation Learning with Cross-Stream Prototypical Contrasting [article]

Martine Toering, Ioannis Gatopoulos, Maarten Stol, Vincent Tao Hu
2021 arXiv   pre-print
Instance-level contrastive learning techniques, which rely on data augmentation and a contrastive loss function, have found great success in the domain of visual representation learning. They are not suitable for exploiting the rich dynamical structure of video however, as operations are done on many augmented instances. In this paper we propose "Video Cross-Stream Prototypical Contrasting", a novel method which predicts consistent prototype assignments from both RGB and optical flow views,
more » ... ating on sets of samples. Specifically, we alternate the optimization process; while optimizing one of the streams, all views are mapped to one set of stream prototype vectors. Each of the assignments is predicted with all views except the one matching the prediction, pushing representations closer to their assigned prototypes. As a result, more efficient video embeddings with ingrained motion information are learned, without the explicit need for optical flow computation during inference. We obtain state-of-the-art results on nearest-neighbour video retrieval and action recognition, outperforming previous best by +3.2% on UCF101 using the S3D backbone (90.5% Top-1 acc), and by +7.2% on UCF101 and +15.1% on HMDB51 using the R(2+1)D backbone.
arXiv:2106.10137v3 fatcat:yj3ph4he25dzjnivxedtug3itq

Conformance Checking of Access Control Policies Specified in XACML

Vincent C. Hu, Evan Martin, JeeHyun Hwang, Tao Xie
2007 Computer Software and Applications Conference (COMPSAC) Proceedings of the IEEE International  
Access control is one of the most fundamental and widely used security mechanisms. Access control mechanisms control which principals such as users or processes have access to which resources in a system. To facilitate managing and maintaining access control, access control policies are increasingly written in specification languages such as XACML. The specification of access control policies itself is often a challenging problem. Furthermore, XACML is intentionally designed to be generic: it
more » ... ovides the freedom in describing access control policies, which are well-known or invented ones. But the flexibility and expressiveness provided by XACML come at the cost of complexity, verbosity, and lack of desirable-property enforcement. Often common properties for specific access control policies may not be satisfied when these policies are specified in XACML, causing the discrepancy between what the policy authors intend to specify and what the actually specified XACML policies reflect. In this position paper, we propose an approach for conducting conformance checking of access control policies specified in XACML based on existing verification and testing tools for XACML policies.
doi:10.1109/compsac.2007.96 dblp:conf/compsac/HuMHX07 fatcat:jzoj2m74x5bz3nc6qjklukoq5u


2011 International journal of software engineering and knowledge engineering  
Mandatory access control (MAC) mechanisms control which users or processes have access to which resources in a system. MAC policies are increasingly specified to facili tate managing and maintaining access control. However, the correct specification of the policies is a very challenging problem. To formally and precisely capture the security properties that MAC should adhere to, MAC models are usually written to bridge the rather wide gap in abstraction between policies and mechanisms. In this
more » ... aper, we pro pose a general approach for property verification for MAC models. The approach defines a standardized structure for MAC models, providing for both property verification and automated generation of test cases. The approach expresses MAC models in the speci fication language of a model checker and expresses generic access control properties in the property language. Then the approach uses the model checker to verify the integrity, coverage, and confinement of these properties for the MAC models and finally generates test cases via combinatorial covering array for the system implementations of the models.
doi:10.1142/s021819401100513x fatcat:arn6q2nc6rdljgps7dgbzdvs3e

Detection of Multiple-Duty-Related Security Leakage in Access Control Policies

JeeHyun Hwang, Tao Xie, Vincent C. Hu
2009 2009 Third IEEE International Conference on Secure Software Integration and Reliability Improvement  
Access control mechanisms control which subjects (such as users or processes) have access to which resources. To facilitate managing access control, policy authors increasingly write access control policies in XACML. Access control policies written in XACML could be amenable to multiple-duty-related security leakage, which grants unauthorized access to a user when the user takes multiple duties (e.g., multiple roles in role-based access control policies). To help policy authors detect
more » ... uty-related security leakage, we develop a novel framework that analyzes policies and detects cases that potentially cause the leakage. In such cases, a user taking multiple roles (e.g., both r 1 and r 2 ) is given a different access decision from the decision given to a user taking an individual role (e.g., r 1 and r 2 , respectively). We conduct experiments on 11 XACML policies and our empirical results show that our framework effectively pinpoints potential multiple-duty-related security leakage for policy authors to inspect.
doi:10.1109/ssiri.2009.63 dblp:conf/ssiri/HwangXH09 fatcat:d3qc2cphhbe5hdxe6oqzlmwamm

Modeling the complete spatiotemporal spread of the COVID-19 epidemic in mainland China

Bisong Hu, Pan Ning, Jingyu Qiu, Vincent Tao, Adam Thomas Devlin, Haiying Chen, Jinfeng Wang, Hui Lin
2021 International Journal of Infectious Diseases  
., Shanghai, China, and applied to identify the generations of the COVID-19 epidemic spreads in mainland China during the early phase (Hu et al., 2020) . 0,ℎ ( ) = ℎ ( ) ℎ =̂ℎ +̂ℎ (1 +̂ℎ ( −̂ℎ) ) ⁄̂ℎ  ... 
doi:10.1016/j.ijid.2021.04.021 pmid:33862212 pmcid:PMC8056483 fatcat:tp35vf4uhvgxtary2hha54imze

The microRNA476a /RFL module regulates adventitious root formation through a mitochondria-dependent pathway in Populus

Changzheng Xu, Yuanxun Tao, Xiaokang Fu, Li Guo, Haitao Xing, Chaofeng Li, HuiLi Su, Xianqiang Wang, Jian Hu, Di Fan, Vincent L. Chiang, Keming Luo
2019 biorxiv/medrxiv  
Adventitious root (AR) formation at the base of stem cuttings determines the efficiency of clonal propagation for woody plants. Many endogenous and environmental factors influence AR formation. However, our knowledge about the regulation of AR development by mitochondrial metabolism in plants is very limited. Here we identified -specific as a novel regulator of wound-induced adventitious rooting via orchestrating mitochondrial homeostasis in poplar. exhibited inducible expression during AR
more » ... tion and directly targets several ( ) genes encoding mitochondrion-localized pentatricopeptide repeat proteins. Genetic modification of - expression revealed the / -mediated dynamic regulation of mitochondrial homeostasis on AR formation in transgenic poplar. Furthermore, mitochondrial perturbation via exogenous chemical inhibitor validated that the / -directed AR formation depended on mitochondrial regulation though modulating the auxin pathway. Our results established a miRNA-directed mitochondrion-auxin signaling cascade required for AR development, providing novel insights into the understanding of mitochondrial regulation on plant developmental plasticity.
doi:10.1101/852178 fatcat:u2za3dwlnfbbjgkvxb6jfsrifi

Niacin analogue, 6-Aminonicotinamide, a novel inhibitor of hepatitis B virus replication and HBsAg production

Fang Ren, Xiao Yang, Zhong-Wen Hu, Vincent Kam Wai Wong, Hong-Yan Xu, Ji-Hua Ren, Shan Zhong, Xiao-Jiong Jia, Hui Jiang, Jie-Li Hu, Xue-Fei Cai, Wen-Lu Zhang (+7 others)
2019 EBioMedicine  
Hepatitis B surface antigen (HBsAg) is one of the important clinical indexes for hepatitis B virus (HBV) infection diagnosis and sustained seroconversion of HBsAg is an indicator for functional cure. However, the level of HBsAg could not be reduced by interferons and nucleoside analogs effectively. Therefore, identification of a new drug targeting HBsAg is urgently needed. In this study, 6-AN was screened out from 1500 compounds due to its low cytotoxicity and high antiviral activity. The
more » ... of 6-AN on HBV was examined in HepAD38, HepG2-NTCP and PHHs cells. In addition, the antivirus effect of 6-AN was also identified in mouse model. 6-AN treatment resulted in a significant decrease of HBsAg and other viral markers both in vitro and in vivo. Furthermore, we found that 6-AN inhibited the activities of HBV SpI, SpII and core promoter by decreasing transcription factor PPARα, subsequently reduced HBV RNAs transcription and HBsAg production. We have identified a novel small molecule to inhibit HBV core DNA, HBV RNAs, HBsAg production, as well as cccDNA to a minor degree both in vitro and in vivo. This study may shed light on the development of a novel class of anti-HBV agent.
doi:10.1016/j.ebiom.2019.10.022 pmid:31680002 pmcid:PMC6945246 fatcat:23jnvtgxxfejrpbikvhmeuvlny

First, second and potential third generation spreads of the COVID-19 epidemic in mainland China: an early exploratory study incorporating location-based service data of mobile devices

Bisong Hu, Jingyu Qiu, Haiying Chen, Vincent Tao, Jinfeng Wang, Hui Lin
2020 International Journal of Infectious Diseases  
: Hui Lin, Jinfeng Wang and Bisong Hu; Resources and Data curation: Vincent Tao, Jingyu Qiu and Hui Lin; Formal analysis: Bisong Hu and Haiying Chen; Methodology: Bisong Hu and Jinfeng Wang; Software  ...  : Jinfeng Wang; Visualization: Bisong Hu; Validation, Bisong Hu and Jinfeng Wang; Writing-original draft: Bisong Hu; Writing-review and editing: Bisong Hu, Jinfeng Wang and Hui Lin.  ... 
doi:10.1016/j.ijid.2020.05.048 pmid:32425632 pmcid:PMC7231483 fatcat:z62dbbjbmfhmte2nqbxnqjf2he

sj-pdf-1-jcb-10.1177_0271678X211034096 - Supplemental material for Longitudinal cortex-wide monitoring of cerebral hemodynamics and oxygen metabolism in awake mice using multi-parametric photoacoustic microscopy

Vincent M Sciortino, Angela Tran, Naidi Sun, Rui Cao, Tao Sun, Yu-Yo Sun, Ping Yan, Fenghe Zhong, Yifeng Zhou, Chia-Yi Kuan, Jin-Moo Lee, Song Hu
2021 Figshare  
M Sciortino, Angela Tran, Naidi Sun, Rui Cao, Tao Sun, Yu-Yo Sun, Ping Yan, Fenghe Zhong, Yifeng Zhou, Chia-Yi Kuan, Jin-Moo Lee and Song Hu in Journal of Cerebral Blood Flow & Metabolism  ...  material, sj-pdf-1-jcb-10.1177_0271678X211034096 for Longitudinal cortex-wide monitoring of cerebral hemodynamics and oxygen metabolism in awake mice using multi-parametric photoacoustic microscopy by Vincent  ... 
doi:10.25384/sage.15062999.v1 fatcat:kwpug4a3drf2djfzeb5aacrf44
« Previous Showing results 1 — 15 out of 2,161 results