The lack of efficient segmentation methods and fully-labeled datasets limits the comprehensive assessment of optical coherence tomography angiography (OCTA) microstructures like retinal vessel network (RVN) and foveal avascular zone (FAZ), which are of great value in ophthalmic and systematic diseases evaluation. Here, we introduce an innovative OCTA microstructure segmentation network (OMSN) by combining an encoder-decoder-based architecture with multi-scale skip connections and the split-attention-based residual network ResNeSt, paying specific attention to OCTA microstructural features while facilitating better model convergence and feature representations. The proposed OMSN achieves excellent single/multi-task performances for RVN or/and FAZ segmentation. Especially, the evaluation metrics on multi-task models outperform single-task models on the same dataset. On this basis, a fully annotated retinal OCTA segmentation (FAROS) dataset is constructed semi-automatically, filling the vacancy of a pixel-level fully-labeled OCTA dataset. OMSN multi-task segmentation model retrained with FAROS further certifies its outstanding accuracy for simultaneous RVN and FAZ segmentation.
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Salient object detection (SOD) aims to determine the most visually attractive objects in an image. With the development of virtual reality technology, 360{\deg} omnidirectional image has been widely used, but the SOD task in 360{\deg} omnidirectional image is seldom studied due to its severe distortions and complex scenes. In this paper, we propose a Multi-Projection Fusion and Refinement Network (MPFR-Net) to detect the salient objects in 360{\deg} omnidirectional image. Different from the existing methods, the equirectangular projection image and four corresponding cube-unfolding images are embedded into the network simultaneously as inputs, where the cube-unfolding images not only provide supplementary information for equirectangular projection image, but also ensure the object integrity of the cube-map projection. In order to make full use of these two projection modes, a Dynamic Weighting Fusion (DWF) module is designed to adaptively integrate the features of different projections in a complementary and dynamic manner from the perspective of inter and intra features. Furthermore, in order to fully explore the way of interaction between encoder and decoder features, a Filtration and Refinement (FR) module is designed to suppress the redundant information between the feature itself and the feature. Experimental results on two omnidirectional datasets demonstrate that the proposed approach outperforms the state-of-the-art methods both qualitatively and quantitatively.
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Knowledge tracing (KT) aims to leverage students' learning histories to estimate their mastery levels on a set of pre-defined skills, based on which the corresponding future performance can be accurately predicted. In practice, a student's learning history comprises answers to sets of massed questions, each known as a session, rather than merely being a sequence of independent answers. Theoretically, within and across these sessions, students' learning dynamics can be very different. Therefore, how to effectively model the dynamics of students' knowledge states within and across the sessions is crucial for handling the KT problem. Most existing KT models treat student's learning records as a single continuing sequence, without capturing the sessional shift of students' knowledge state. To address the above issue, we propose a novel hierarchical transformer model, named HiTSKT, comprises an interaction(-level) encoder to capture the knowledge a student acquires within a session, and a session(-level) encoder to summarise acquired knowledge across the past sessions. To predict an interaction in the current session, a knowledge retriever integrates the summarised past-session knowledge with the previous interactions' information into proper knowledge representations. These representations are then used to compute the student's current knowledge state. Additionally, to model the student's long-term forgetting behaviour across the sessions, a power-law-decay attention mechanism is designed and deployed in the session encoder, allowing it to emphasize more on the recent sessions. Extensive experiments on three public datasets demonstrate that HiTSKT achieves new state-of-the-art performance on all the datasets compared with six state-of-the-art KT models.
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Interoperability issue is a significant problem in Building Information Modeling (BIM). Object type, as a kind of critical semantic information needed in multiple BIM applications like scan-to-BIM and code compliance checking, also suffers when exchanging BIM data or creating models using software of other domains. It can be supplemented using deep learning. Current deep learning methods mainly learn from the shape information of BIM objects for classification, leaving relational information inherent in the BIM context unused. To address this issue, we introduce a two-branch geometric-relational deep learning framework. It boosts previous geometric classification methods with relational information. We also present a BIM object dataset IFCNet++, which contains both geometric and relational information about the objects. Experiments show that our framework can be flexibly adapted to different geometric methods. And relational features do act as a bonus to general geometric learning methods, obviously improving their classification performance, thus reducing the manual labor of checking models and improving the practical value of enriched BIM models.
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Full electronic automation in stock exchanges has recently become popular, generating high-frequency intraday data and motivating the development of near real-time price forecasting methods. Machine learning algorithms are widely applied to mid-price stock predictions. Processing raw data as inputs for prediction models (e.g., data thinning and feature engineering) can primarily affect the performance of the prediction methods. However, researchers rarely discuss this topic. This motivated us to propose three novel modelling strategies for processing raw data. We illustrate how our novel modelling strategies improve forecasting performance by analyzing high-frequency data of the Dow Jones 30 component stocks. In these experiments, our strategies often lead to statistically significant improvement in predictions. The three strategies improve the F1 scores of the SVM models by 0.056, 0.087, and 0.016, respectively.
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我们介绍了第一个基于学习的可重建性预测指标,以改善使用无人机的大规模3D城市场景获取的视图和路径计划。与以前的启发式方法相反,我们的方法学习了一个模型,该模型明确预测了从一组观点重建3D城市场景的能力。为了使这种模型可训练并同时适用于无人机路径计划,我们在培训期间模拟了基于代理的3D场景重建以设置预测。具体而言,我们设计的神经网络经过训练,可以预测场景的重构性,这是代理几何学的函数,一组观点,以及在飞行中获得的一系列场景图像。为了重建一个新的城市场景,我们首先构建了3D场景代理,然后依靠我们网络的预测重建质量和不确定性度量,基于代理几何形状,以指导无人机路径计划。我们证明,与先前的启发式措施相比,我们的数据驱动的可重建性预测与真实的重建质量更加紧密相关。此外,我们学到的预测变量可以轻松地集成到现有的路径计划中,以产生改进。最后,我们根据学习的可重建性设计了一个新的迭代视图计划框架,并在重建合成场景和真实场景时展示新计划者的卓越性能。
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对成对比较的排名聚集在选举,体育比赛,建议和信息检索中表现出了令人鼓舞的结果。但是,与众多有关计算和统计特征的研究工作相反,对这种算法的安全问题几乎没有关注。在巨额利润的推动下,潜在的对手具有强大的动力和动力来操纵排名清单。同时,文献中没有很好地研究等级聚集方法的内在脆弱性。为了充分了解可能的风险,我们专注于有目的的对手,他们希望通过修改本文中的成对数据来指定汇总结果。从动力学系统的角度来看,具有目标排名列表的攻击行为是属于对手和受害者组成的固定点。为了执行目标攻击,我们将对手和受害者之间的相互作用作为游戏理论框架,由两个连续的操作员组成,同时建立了NASH平衡。然后,构建了针对Hodgerank和RankCentrality的两个程序,以产生原始数据的修改。此外,我们证明,一旦对手掌握了完整的信息,受害者将产生目标排名列表。值得注意的是,所提出的方法允许对手只保留不完整的信息或不完美的反馈并执行有目的的攻击。一系列玩具模拟和几个现实世界数据实验证明了建议的目标攻击策略的有效性。这些实验结果表明,所提出的方法可以实现攻击者的目标,即扰动排名列表的领先候选人是对手指定的。
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OD区域对之间的原点污染(OD)矩阵记录定向流数据。矩阵中复杂的时空依赖性使OD矩阵预测(ODMF)问题不仅可以棘手,而且是非平凡的。但是,大多数相关方法都是为在特定的应用程序方案中预测非常短的序列时间序列而设计的,在特定的应用程序场景中,该方法无法满足方案和预测实用应用长度的差异要求。为了解决这些问题,我们提出了一个名为Odformer的类似变压器的模型,具有两个显着特征:(i)新型的OD注意机制,该机制捕获了相同起源(目的地)之间的特殊空间依赖性,可大大提高与捕获OD区域之间空间依赖关系的2D-GCN结合后,预测交叉应用方案的模型。 (ii)一个时期的自我注意力,可以有效地预测长序列OD矩阵序列,同时适应不同情况下的周期性差异。在三个应用程序背景(即运输流量,IP骨干网络流量,人群流)中进行的慷慨实验表明,我们的方法的表现优于最新方法。
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隐私权联合学习允许多个用户与中央服务器协调共同培训模型。服务器仅学习最终聚合结果,从而防止用户(私有)培训数据从单个模型更新中泄漏。但是,保持单个更新私有,使恶意用户可以执行拜占庭式攻击并降低模型准确性,而无需检测到。针对拜占庭工人的最佳防御能力依赖于基于排名的统计数据,例如中位数,以查找恶意更新。但是,在安全域中实施基于隐私的排名统计信息在安全域中是不平淡无奇的,因为它需要对所有单个更新进行排序。我们建立了第一个私人鲁棒性检查,该检查在汇总模型更新上使用基于高断点等级的统计信息。通过利用随机聚类,我们在不损害隐私的情况下显着提高了防御的可扩展性。我们利用零知识证明中的派生统计界限来检测和删除恶意更新,而无需透露私人用户更新。我们的新颖框架Zprobe可以使拜占庭式的弹性和安全的联合学习。经验评估表明,Zprobe提供了低架空解决方案,以防御最新的拜占庭袭击,同时保留隐私。
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机器学习和认知科学的最新工作表明,了解因果信息对于智力的发展至关重要。使用``Blicket otter''环境的认知科学的广泛文献表明,孩子们擅长多种因果推理和学习。我们建议将该环境适应机器​​学习代理。当前机器学习算法的关键挑战之一是建模和理解因果关系:关于因果关系集的可转移抽象假设。相比之下,即使是幼儿也会自发学习和使用因果关系。在这项工作中,我们提出了一个新的基准 - 一种灵活的环境,可以评估可变因果溢出物下的现有技术 - 并证明许多现有的最新方法在这种环境中概括了困难。该基准的代码和资源可在https://github.com/cannylab/casual_overhypothess上获得。
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