Dimensionality reduction has become an important research topic as demand for interpreting high-dimensional datasets has been increasing rapidly in recent years. There have been many dimensionality reduction methods with good performance in preserving the overall relationship among data points when mapping them to a lower-dimensional space. However, these existing methods fail to incorporate the difference in importance among features. To address this problem, we propose a novel meta-method, DimenFix, which can be operated upon any base dimensionality reduction method that involves a gradient-descent-like process. By allowing users to define the importance of different features, which is considered in dimensionality reduction, DimenFix creates new possibilities to visualize and understand a given dataset. Meanwhile, DimenFix does not increase the time cost or reduce the quality of dimensionality reduction with respect to the base dimensionality reduction used.

尽管机器学习取得了巨大进步（ML），但数据不平衡的培训仍然在许多现实世界中构成挑战。在解决此问题的一系列不同技术中，采样算法被视为有效的解决方案。但是，问题更为根本，许多作品强调了实例硬度的重要性。这个问题是指管理不安全或可能嘈杂的实例的重要性，这些实例更可能被错误分类并作为分类绩效不佳的根本原因。本文介绍了Hardvis，这是一种视觉分析系统，旨在处理实例硬度，主要在分类场景中。我们提出的系统协助用户在视觉上比较数据类型的不同分布，根据局部特征选择实例类型，这些实例后来将受主动采样方法的影响，并验证来自底漆或过采样技术的建议对ML模型有益。此外，我们允许用户找到和采样轻松且难以对所有课程的培训实例进行分类，而不是统一地采样/过采样。用户可以从不同角度探索数据子集以决定所有这些参数，而HardVis则跟踪其步骤并评估模型在测试集中分别评估模型的预测性能。最终结果是一个均衡的数据集，可增强ML模型的预测能力。通过假设使用情况和用例证明了Hardvis的功效和有效性。最后，我们还研究了系统的有用，基于我们从ML专家那里收到的反馈。

Visual Analytics（VA）工具和技术已经有助于支持用户构建更好的分类模型，解释模型的整体逻辑和审计结果。在不同的方向上，最近将VA应用于将分类模型转换为描述性机制而不是预测性。该想法是使用这些模型作为数据模式的代理，可视化模型以了解数据所代表的现象。虽然非常有用和鼓舞人心，但少数提出的方法选择使用低复杂的分类模型来促进直接的解释，呈现捕获复杂数据模式的限制。在本文中，我们呈现VAX（多变量数据说明），一种新的VA方法，以支持多变量数据集中模式的识别和视觉解释。与现有的类似方法不同，VAX使用跳跃新兴模式的概念来识别和聚合几种多样化模式，通过数据变量的逻辑组合产生解释。通过使用两个现实世界数据集覆盖不同方案的使用情况，通过使用案例来证明VAX来解释复杂多变量数据集的潜力。

维数减少（DR）技术有助于分析师理解高维空间的模式。这些技术通常由散点图表示，在不同的科学域中使用，并促进集群和数据样本之间的相似性分析。对于包含许多粒度的数据集或者当分析遵循信息可视化Mantra时，分层DR技术是最合适的方法，因为它们预先呈现了主要结构和需求的详细信息。然而，当前的分层DR技术并不完全能够解决文献问题，因为它们不保留跨分层级别的投影心理映射，或者不适合大多数数据类型。这项工作提出了Humap，一种新颖的等级维度减少技术，旨在灵活地保护本地和全球结构，并在整个分层勘探中保留心理贴图。我们提供了与现有的等级方法相比我们技术优势的经验证据，并显示了两种案例研究以证明其优势。

知道如何在搜索引擎（SES）（例如Google或Wikipedia）中构建基于文本的搜索查询（SQS）已成为一项基本技能。尽管可以通过此类SE提供大量数据，但大多数结构化数据集都生活在其范围之外。可视化工具有助于这一限制，但是没有这样的工具接近通过通用SES获得的大量信息。为了填补这一空白，本文介绍了Q4EDA，这是一个新颖的框架，可转换用户在时间序列的视觉表示上执行的视觉选择查询，提供有效且稳定的SQS，可用于通用SES和相关信息的建议。用户通过将Gapminder的线条复制品与填充有Wikipedia文档的SE联系起来的应用程序来介绍和验证Q4EDA的实用性，并显示了Q4EDA如何支持和增强联合国世界指标的探索性分析。尽管有一些局限性，Q4EDA在其建议中仍然是独一无二的，它代表了提供基于用户与视觉表示的用户交互来查询文本信息的解决方案的真正进步。

Dimensionality Reduction (DR) scatterplot layouts have become a ubiquitous visualization tool for analyzing multidimensional datasets. Despite their popularity, such scatterplots suffer from occlusion, especially when informative glyphs are used to represent data instances, potentially obfuscating critical information for the analysis under execution. Different strategies have been devised to address this issue, either producing overlap-free layouts which lack the powerful capabilities of contemporary DR techniques in uncovering interesting data patterns or eliminating overlaps as a post-processing strategy. Despite the good results of post-processing techniques, most of the best methods typically expand or distort the scatterplot area, thus reducing glyphs' size (sometimes) to unreadable dimensions, defeating the purpose of removing overlaps. This paper presents Distance Grid (DGrid), a novel post-processing strategy to remove overlaps from DR layouts that faithfully preserves the original layout's characteristics and bounds the minimum glyph sizes. We show that DGrid surpasses the state-of-the-art in overlap removal (through an extensive comparative evaluation considering multiple different metrics) while also being 2 or 3 orders of magnitude faster for large datasets.

For conceptual design, engineers rely on conventional iterative (often manual) techniques. Emerging parametric models facilitate design space exploration based on quantifiable performance metrics, yet remain time-consuming and computationally expensive. Pure optimisation methods, however, ignore qualitative aspects (e.g. aesthetics or construction methods). This paper provides a performance-driven design exploration framework to augment the human designer through a Conditional Variational Autoencoder (CVAE), which serves as forward performance predictor for given design features as well as an inverse design feature predictor conditioned on a set of performance requests. The CVAE is trained on 18'000 synthetically generated instances of a pedestrian bridge in Switzerland. Sensitivity analysis is employed for explainability and informing designers about (i) relations of the model between features and/or performances and (ii) structural improvements under user-defined objectives. A case study proved our framework's potential to serve as a future co-pilot for conceptual design studies of pedestrian bridges and beyond.

联合学习是一种新颖的框架，允许多个设备或机构在保留其私有数据时协同地培训机器学习模型。这种分散的方法易于遭受数据统计异质性的后果，无论是在不同的实体还是随着时间的推移，这可能导致缺乏会聚。为避免此类问题，在过去几年中提出了不同的方法。然而，数据可能在许多不同的方式中是异构的，并且当前的建议并不总是确定他们正在考虑的异质性的那种。在这项工作中，我们正式地分类数据统计异质性，并审查能够面对它的最显着的学习策略。与此同时，我们介绍了其他机器学习框架的方法，例如持续学习，也处理数据异质性，并且可以很容易地适应联邦学习设置。

In this paper we explore the task of modeling (semi) structured object sequences; in particular we focus our attention on the problem of developing a structure-aware input representation for such sequences. In such sequences, we assume that each structured object is represented by a set of key-value pairs which encode the attributes of the structured object. Given a universe of keys, a sequence of structured objects can then be viewed as an evolution of the values for each key, over time. We encode and construct a sequential representation using the values for a particular key (Temporal Value Modeling - TVM) and then self-attend over the set of key-conditioned value sequences to a create a representation of the structured object sequence (Key Aggregation - KA). We pre-train and fine-tune the two components independently and present an innovative training schedule that interleaves the training of both modules with shared attention heads. We find that this iterative two part-training results in better performance than a unified network with hierarchical encoding as well as over, other methods that use a {\em record-view} representation of the sequence \cite{de2021transformers4rec} or a simple {\em flattened} representation of the sequence. We conduct experiments using real-world data to demonstrate the advantage of interleaving TVM-KA on multiple tasks and detailed ablation studies motivating our modeling choices. We find that our approach performs better than flattening sequence objects and also allows us to operate on significantly larger sequences than existing methods.

Optical coherence tomography (OCT) captures cross-sectional data and is used for the screening, monitoring, and treatment planning of retinal diseases. Technological developments to increase the speed of acquisition often results in systems with a narrower spectral bandwidth, and hence a lower axial resolution. Traditionally, image-processing-based techniques have been utilized to reconstruct subsampled OCT data and more recently, deep-learning-based methods have been explored. In this study, we simulate reduced axial scan (A-scan) resolution by Gaussian windowing in the spectral domain and investigate the use of a learning-based approach for image feature reconstruction. In anticipation of the reduced resolution that accompanies wide-field OCT systems, we build upon super-resolution techniques to explore methods to better aid clinicians in their decision-making to improve patient outcomes, by reconstructing lost features using a pixel-to-pixel approach with an altered super-resolution generative adversarial network (SRGAN) architecture.