Human Factors in Streaming Data Analysis: Challenges and Opportunities for Information Visualization

Real‐world systems change continuously. In domains such as traffic monitoring or cyber security, such changes occur within short time scales. This results in a streaming data problem and leads to unique challenges for the human in the loop, as analysts have to ingest and make sense of dynamic patterns in real time. While visualizations are being increasingly used by analysts to derive insights from streaming data, we lack a thorough characterization of the human‐centred design problems and a critical analysis of the state‐of‐the‐art solutions that exist for addressing these problems. In this paper, our goal is to fill this gap by studying how the state of the art in streaming data visualization handles the challenges and reflect on the gaps and opportunities. To this end, we have three contributions in this paper: (i) problem characterization for identifying domain‐specific goals and challenges for handling streaming data, (ii) a survey and analysis of the state of the art in streaming data visualization research with a focus on how visualization design meets challenges specific to change perception and (iii) reflections on the design trade‐offs, and an outline of potential research directions for addressing the gaps in the state of the art.     

Hypersliceplorer: Interactive visualization of shapes in multiple dimensions

In this paper we present Hypersliceplorer, an algorithm for generating 2D slices of multi‐dimensional shapes defined by a simplical mesh. Often, slices are generated by using a parametric form and then constraining parameters to view the slice. In our case, we developed an algorithm to slice a simplical mesh of any number of dimensions with a two‐dimensional slice. In order to get a global appreciation of the multi‐dimensional object, we show multiple slices by sampling a number of different slicing points and projecting the slices into a single view per dimension pair. These slices are shown in an interactive viewer which can switch between a global view (all slices) and a local view (single slice). We show how this method can be used to study regular polytopes, differences between spaces of polynomials, and multi‐objective optimization surfaces.     

基于视觉曲率估算的文物线图绘制方法

针对表面富含噪声的文物三维模型特征线的有效提取问题,分析了预处理阶段导致纹理细节丢失的原因,提出了一种基于视觉曲率估算的文物线图自动绘制方法。首先,对三角网格模型顶点的高度函数空间进行均匀采样,通过统计高度函数中极值点的个数,实现对模型顶点的视觉曲率估算;然后,根据多尺度约束下模型顶点的视觉曲率分布,将模型划分为平坦区域和特征区域;接着,依据考古领域均值对特征区域的顶点进行锐化滤波,计算出新的三角网格模型的顶点坐标;最后,对三角网格模型提取特征轮廓线,实现对文物线图的自动绘制。实验结果表明,基于视觉曲率的特征轮廓线在保留文物模型表面纹理细节的同时,有效避免了简单脊线/谷线法绘制线图呈现的尖锐现象。     

万家寨引水工程北干线有压倒虹吸管道充水过程研究

为了充分发挥万家寨引水工程北干线在长距离输水管路的潜在效益,基于北干线有压的1#、2#倒虹吸PCCP管道工程,以1#倒虹吸朔州在线调流阀前管道充水过程为例,分析研究了考虑空气阀作用工况下可能产生的水击压力以及不同的充水流量下1#倒虹吸沿程控制点的充水时间。研究成果为万家寨引水工程北干线充水过程研究提供了理论基础。     

危险环境消防侦察机器人视轴规划算法研究

针对自主研发的危险环境消防侦察机器人展开研究。此机器人为履带式车身,装载一3自由度机械,高清侦察相机固定在机械臂末端。研究内容为在已知环境下自主规划机械臂规避障碍物,并调节相机视轴方向,实现对环境重点区域的锁定。首先对机械臂建立指数积（POE）正运动学模型,使用Minkowski和与三维凸包检测算法作为碰撞检测算法,使用蒙特卡洛方法在构型空间采样。再通过采样数据匹配末端视角方向,在末端建立虚拟连杆,使用碰撞检测算法保证实现视线无遮挡。仿真实验证明,使用此算法能够快速将相机视轴锁定至重点区域并保证无遮挡,且机械臂末端相机处于最佳位姿。     

Sclow Plots: Visualizing Empty Space

Scatter plots are mostly used for correlation analysis, but are also a useful tool for understanding the distribution of high‐dimensional point cloud data. An important characteristic of such distributions are clusters, and scatter plots have been used successfully to identify clusters in data. Another characteristic of point cloud data that has received less attention so far are regions that contain no or only very few data points. We show that augmenting scatter plots by projections of flow lines along the gradient vector field of the distance function to the point cloud reveals such empty regions or voids. The augmented scatter plots, that we call sclow plots, enable a much better understanding of the geometry underlying the point cloud than traditional scatter plots, and by that support tasks like dimension inference, detecting outliers, or identifying data points at the interface between clusters. We demonstrate the feasibility of our approach on synthetic and real world data sets.     

Intrinsic Decompositions for Image Editing

Intrinsic images are a mid‐level representation of an image that decompose the image into reflectance and illumination layers. The reflectance layer captures the color/texture of surfaces in the scene, while the illumination layer captures shading effects caused by interactions between scene illumination and surface geometry. Intrinsic images have a long history in computer vision and recently in computer graphics, and have been shown to be a useful representation for tasks ranging from scene understanding and reconstruction to image editing. In this report, we review and evaluate past work on this problem. Specifically, we discuss each work in terms of the priors they impose on the intrinsic image problem. We introduce a new synthetic ground‐truth dataset that we use to evaluate the validity of these priors and the performance of the methods. Finally, we evaluate the performance of the different methods in the context of image‐editing applications.     

Generating Tile Maps

Tile maps are an important tool in thematic cartography with distinct qualities (and limitations) that distinguish them from better‐known techniques such as choropleths, cartograms and symbol maps. Specifically, tile maps display geographic regions as a grid of identical tiles so large regions do not dominate the viewer's attention and small regions are easily seen. Furthermore, complex data such as time series can be shown on each tile in a consistent format, and the grid layout facilitates comparisons across tiles. Whilst a small number of handcrafted tile maps have become popular, the time‐consuming process of creating new tile maps limits their wider use. To address this issue, we present an algorithm that generates a tile map of the specified type (e.g. square, hexagon, triangle) from raw shape data. Since the ‘best’ tile map depends on the specific geography visualized and the task to be performed, the algorithm generates and ranks multiple tile maps and allows the user to choose the most appropriate. The approach is demonstrated on a range of examples using a prototype browser‐based application.     

小型高可靠分体式多冗余线位移传感器研制

为了满足新型战略导弹武器的研制需求,要求伺服机构结构紧凑,集成度高,并能够适应恶劣的工作环境和有限的空间结构,实现伺服作动器齿条位移的测量及反馈。一种小型高可靠分体式多冗余线位移传感器的研制,在传统的分体式线位移传感器的基础上,通过四冗余的结构设计,印制电阻膜的设计,零位输出可调的设计,多指型电刷受力的优化设计,实现了线位移传感器的结构小型化和紧凑化的冗余功能,能够耐高温,工作寿命长,线性精度高的性能。试验和仿真分析表明设计技术方案有效可行,能够满足伺服系统的要求。     

BRDF Representation and Acquisition

Photorealistic rendering of real world environments is important in a range of different areas; including Visual Special effects, Interior/Exterior Modelling, Architectural Modelling, Cultural Heritage, Computer Games and Automotive Design. Currently, rendering systems are able to produce photorealistic simulations of the appearance of many real‐world materials. In the real world, viewer perception of objects depends on the lighting and object/material/surface characteristics, the way a surface interacts with the light and on how the light is reflected, scattered, absorbed by the surface and the impact these characteristics have on material appearance. In order to re‐produce this, it is necessary to understand how materials interact with light. Thus the representation and acquisition of material models has become such an active research area. This survey of the state‐of‐the‐art of BRDF Representation and Acquisition presents an overview of BRDF (Bidirectional Reflectance Distribution Function) models used to represent surface/material reflection characteristics, and describes current acquisition methods for the capture and rendering of photorealistic materials.