最近，多模态命名实体识别（MNER）引起了很多关注。大多数工作通过从预训练对象检测器获得的区域级视觉表示使用图像信息，并依赖于注意力机制来模拟图像和文本表示之间的交互。然而，难以模拟这种交互，因为图像和文本表示分别在其各自的模态的数据上训练，并且在相同的空间中不对齐。由于文本表示在MNER中取得最重要的作用，在本文中，我们提出了{\ bf i} mage - {\ bf t} ext {\ bf a} lignments（ita）将图像特征对准到文本空间中，这样可以更好地利用基于变压器的预磨削文本嵌入的注意机制。 ITA首先在本地和全局将区域对象标记和图像级标题视为可视上下文，将其与输入文本连接为新的跨模型输入，然后将其送入预训练的文本嵌入模型。这使得预先训练的文本嵌入模型的注意模块更容易模拟两个模态之间的交互，因为它们都在文本空间中表示。 ITA进一步对齐从跨模型输入和文本输入视图预测的输出分布，使得MNER模型可以更实用和鲁棒到图像中的噪声。在我们的实验中，我们表明ITA模型可以在多模态命名实体识别数据集上实现最先进的准确性，即使没有图像信息也是如此。

Recent advances in Named Entity Recognition (NER) show that document-level contexts can significantly improve model performance. In many application scenarios, however, such contexts are not available. In this paper, we propose to find external contexts of a sentence by retrieving and selecting a set of semantically relevant texts through a search engine, with the original sentence as the query. We find empirically that the contextual representations computed on the retrieval-based input view, constructed through the concatenation of a sentence and its external contexts, can achieve significantly improved performance compared to the original input view based only on the sentence. Furthermore, we can improve the model performance of both input views by Cooperative Learning, a training method that encourages the two input views to produce similar contextual representations or output label distributions. Experiments show that our approach can achieve new state-of-the-art performance on 8 NER data sets across 5 domains.

Metaheuristics are popularly used in various fields, and they have attracted much attention in the scientific and industrial communities. In recent years, the number of new metaheuristic names has been continuously growing. Generally, the inventors attribute the novelties of these new algorithms to inspirations from either biology, human behaviors, physics, or other phenomena. In addition, these new algorithms, compared against basic versions of other metaheuristics using classical benchmark problems without shift/rotation, show competitive performances. In this study, we exhaustively tabulate more than 500 metaheuristics. To comparatively evaluate the performance of the recent competitive variants and newly proposed metaheuristics, 11 newly proposed metaheuristics and 4 variants of established metaheuristics are comprehensively compared on the CEC2017 benchmark suite. In addition, whether these algorithms have a search bias to the center of the search space is investigated. The results show that the performance of the newly proposed EBCM (effective butterfly optimizer with covariance matrix adaptation) algorithm performs comparably to the 4 well performing variants of the established metaheuristics and possesses similar properties and behaviors, such as convergence, diversity, exploration and exploitation trade-offs, in many aspects. The performance of all 15 of the algorithms is likely to deteriorate due to certain transformations, while the 4 state-of-the-art metaheuristics are less affected by transformations such as the shifting of the global optimal point away from the center of the search space. It should be noted that, except EBCM, the other 10 new algorithms proposed mostly during 2019-2020 are inferior to the well performing 2017 variants of differential evolution and evolution strategy in terms of convergence speed and global search ability on CEC 2017 functions.

The Multi-Objective Shortest Path Problem, typically posed on a graph, determines a set of paths from a start vertex to a destination vertex while optimizing multiple objectives. In general, there does not exist a single solution path that can simultaneously optimize all the objectives and the problem thus seeks to find a set of so-called Pareto-optimal solutions. To address this problem, several Multi-Objective A* (MOA*) algorithms were recently developed to quickly compute solutions with quality guarantees. However, these MOA* algorithms often suffer from high memory usage, especially when the branching factor (i.e., the number of neighbors of any vertex) of the graph is large. This work thus aims at reducing the high memory consumption of MOA* with little increase in the runtime. In this paper, we first extend the notion of "partial expansion" (PE) from single-objective to multi-objective and then fuse this new PE technique with EMOA*, a recent runtime efficient MOA* algorithm. Furthermore, the resulting algorithm PE-EMOA* can balance between runtime and memory efficiency by tuning a user-defined hyper-parameter.

对具有代理商初始位置未知的有限3D环境的多代理探索是一个具有挑战性的问题。它需要快速探索环境，并坚定合并代理商构建的子图。我们认为现有方法是侵略性或保守的：在检测到重叠时，积极的策略合并了两种由不同代理构建的子图，这可能导致由于对重叠的错误阳性检测而导致不正确的合并，因此是如此。不健全。保守策略指导一个代理人在合并之前重新审视另一个代理商的过量验证历史轨迹，这可以降低由于对同一空间的反复探索而引起的勘探效率。为了巧妙地平衡子图合并和勘探效率的鲁棒性，我们为基于激光雷达的多代理探索开发了一种新方法，该方法可以指导一个代理商以\ emph {自适应}方式重复另一个代理商的轨迹子图合并过程的指标。此外，我们的方法通过计划合并子图的代理人共同计划，以进一步提高勘探效率，以\ emph {Cooperative}方式将最近的单格分层勘探策略扩展到多个代理。我们的实验表明，我们的方法平均比基线高出50 \％，同时稳固地合并子映射。

在不同情况下，机器人有可能执行搜索各种应用程序。我们的工作是由人道主义助理和灾难救济（HADR）激发的，在存在冲突的标准，目标和信息的情况下，找到生命的迹象通常至关重要。我们认为，厄运搜索可以提供一个框架来利用可用信息，并为HADR等应用程序探索新信息，尤其是在时间本质上。千古搜索算法规划轨迹，使得在一个地区所花费的时间与该地区的信息量成正比，并且能够自然平衡剥削（近视搜索高信息搜索区域）和探索（访问搜索空间的所有位置以获取新的信息）。现有的Ergodic搜索算法以及其他基于信息的方法通常仅使用单个信息图考虑搜索。但是，在许多情况下，使用多个编码不同类型相关信息的多个信息图很常见。当前的厄运搜索方法没有同时的能力，也不具有平衡信息优先级的方法。这使我们提出了一个多目标的千古搜索（MOES）问题，旨在找到所谓的帕累托最佳解决方案，目的是为人类的决策者提供各种解决方案，这些解决方案在相互矛盾的标准之间进行贸易。为了有效地解决MOE，我们开发了一个称为顺序局部Ergodic搜索（SLE）的框架，该框架将MOES问题转换为“重量空间覆盖率”问题。它利用了厄隆搜索方法的最新进展以及局部优化的想法，以有效地近似帕累托最佳前沿。我们的数值结果表明，SLE的运行速度明显快于基线方法。

背景：心肌灌注SPECT（MPS）对左心室（LV）功能的评估依赖于准确的心肌分割。本文的目的是开发和验证一种新的方法，该方法将深度学习与形状先验结合在一起，以精确提取LV心肌以自动测量LV功能参数。方法：开发了与形状变形模块集成三维（3D）V-NET的分割体系结构。使用动态编程（DP）算法生成的形状先验，然后在模型训练期间限制并指导模型输出，以快速收敛和改善性能。分层的5倍交叉验证用于训练和验证我们的模型。结果：我们提出的方法的结果与地面真理的结果一致。我们提出的模型的骰子相似性系数（DSC）为0.9573（0.0244），0.9821（0.0137）和0.9903（0.0041），Hausdorff距离（HD）6.7529（2.7334）（2.7334）mm，7.2507（3.2507（3.1952）MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM MM，和7.6122 3.0134）MM分别提取心内膜，心肌和心外膜。结论：我们提出的方法在提取LV心肌轮廓和评估LV功能方面具有很高的精度。

Background. Functional assessment of right ventricle (RV) using gated myocardial perfusion single-photon emission computed tomography (MPS) heavily relies on the precise extraction of right ventricular contours. In this paper, we present a new deep-learning-based model integrating both the spatial and temporal features in gated MPS images to perform the segmentation of the RV epicardium and endocardium. Methods. By integrating the spatial features from each cardiac frame of the gated MPS and the temporal features from the sequential cardiac frames of the gated MPS, we developed a Spatial-Temporal V-Net (ST-VNet) for automatic extraction of RV endocardial and epicardial contours. In the ST-VNet, a V-Net is employed to hierarchically extract spatial features, and convolutional long-term short-term memory (ConvLSTM) units are added to the skip-connection pathway to extract the temporal features. The input of the ST-VNet is ECG-gated sequential frames of the MPS images and the output is the probability map of the epicardial or endocardial masks. A Dice similarity coefficient (DSC) loss which penalizes the discrepancy between the model prediction and the ground truth was adopted to optimize the segmentation model. Results. Our segmentation model was trained and validated on a retrospective dataset with 45 subjects, and the cardiac cycle of each subject was divided into 8 gates. The proposed ST-VNet achieved a DSC of 0.8914 and 0.8157 for the RV epicardium and endocardium segmentation, respectively. The mean absolute error, the mean squared error, and the Pearson correlation coefficient of the RV ejection fraction (RVEF) between the ground truth and the model prediction were 0.0609, 0.0830, and 0.6985. Conclusion. Our proposed ST-VNet is an effective model for RV segmentation. It has great promise for clinical use in RV functional assessment.

增量图诸如D * Lite重用之前的算法，并且可能部分搜索，以加快后续路径规划任务。在本文中，我们有兴趣开发增量图搜索算法，以便寻找问题，同时优化旅行风险，到达时间等的多个目标。这是具有挑战性的，因为在多目标设置中，“帕累托 - 最优” “解决方案可以对图表的大小呈指数级增长。本文提出了一种新的多目标增量搜索算法，称为基于多目标路径的D * Lite（MOPBD *），它利用基于路径的扩展策略来修剪主导的解决方案。此外，我们介绍了MOPBD *的两个变体，以进一步提高搜索效率，并近似帕累托最优的前沿。我们在数值上评估了MOPBD *及其在各种地图中的变体的性能，其中包括两个和三个目标。结果表明，我们的方法比从头开始搜索的方法更有效，并且比多目标路径规划的现有增量方法快速升至幅度速度快。

传统的多代理路径规划者通常在优化单个物镜的同时计算路径的集合，例如路径长度。然而，许多应用可能需要多个目标，例如在规划期间同时优化的燃料消耗和完井时间，并且这些标准可能无法容易地进行比较，有时彼此竞争。天真地应用现有的多目标搜索算法，例如多目标A *（MoA *），以多代理路径查找可能被证明是效率低，作为可能的解决方案的空间的大小，即帕累托最优集合，可以用代理的数量（搜索空间的维度）指数增长。本文介绍了一种名为基于多目标冲突的搜索（Mo-CBS）的方法，该方法通过利用基于冲突的搜索（CBS），是单目标多代理的公知算法来绕过这种所谓的维度诅咒路径发现，以及多目标优化文献的优势原则。我们还开发了MO-CBS的几种变体，以进一步提高其性能。我们证明了MO-CBS及其变体能够计算整个帕累托最优集合。数值结果表明，Mo-CBS优于MoA *以及妈妈*，最近开发的最先进的多目标多功能策划员。