Mei C. Chuah

On the semantics of interactive visualizations

Interactive techniques are powerful tools for manipulating visualizations to analyze, communicate and acquire information. This is especially true for large data sets or complex 3D visualizations. Although many new types of interaction have been introduced recently, very little work has been done on understanding what their components are, how they are related and how they can be combined. This paper begins to address these issues with a framework for classifying interactive visualizations. Our goal is a framework that will enable us to develop toolkits for assembling visualization interfaces both interactively and automatically.

Information rich glyphs for software management data

Three high-dimensional glyphs for viewing software project management data assist in perhaps the most challenging engineering task in modern times managing large software projects. In data exploration, glyphs refer to graphical objects or symbols that represent data through visual parameters that are either spatial (positions x or y), retinal (color and size), or temporal. Common examples of graphical objects include the bars in a bar chart or the points within a scatter plot. We focus on glyphs for visualizing software project management data. Any large-scale project will have many different classes of resources (lab equipment, staff time, machine cycles, disk resources, interim deliverables, and customer commitments) that must be scheduled and tracked. Inevitably, problems will arise and solutions must be found. To support the management process, information systems collect and maintain large status databases. We aim to support and improve the understanding of this information through visualization. Our glyphs are designed to expose patterns among sets of software artifacts and to help identify differences between items.

SDM: selective dynamic manipulation of visualizations

In this paper we present a new set of interactive techniques for 2D and 3D visualizations. This set of techniques is called SDM (Selective Dynamic Manipulation). Selective, indicating our goal for providing a high degree of user control in selecting an object set, in selecting interactive techniques and the properties they affect, and in the degree to which a user action affects the visualization. Dynamic, indicating that the interactions all occur in real-time and that interactive animation is used to provide better contextual information to users in response to an action or operation. Manipulation, indicating the types of interactions we provide, where users can directly move objects and transform their appearance to perform different tasks. While many other approaches only provide interactive techniques in isolation, SDM supports a suite of techniques which users can combine to solve a wide variety of problems.

SageTools: an intelligent environment for sketching, browsing, and customizing data-graphics

Our approach views data-graphic design as two complementary processes: design as a constructive process of selecting and arranging graphical elements, and design as a process of browsing and customizing previous cases. We present three novel tools for supporting these processes. SageBrush assembles data-graphics from primitive elements like bars, lines, and axes. SageBook browses previously created data-graphics relevant to current needs. SAGE automatically designs data-graphics, interpreting the users specifications as conveyed with the other tools. The combined environment, SageTools, enhances user-directed design by providing automatic presentation capabilities with styles of interaction that support data-graphic design.

Analyzing graphic and textual layouts with GOMS: results of a preliminary analysis

We combined previous research on GOMS modeling with some simple assumptions about visual search strategies to make zero-parameter predictions of the time necessary to perform a task on four different graphic and textual displays. We compared these predictions to empirical measures of performance time and obtained an absolute average percent difference of 8%. These results indicate that GOMS may be extended to be a useful tool for analyzing different layouts. KEY WORD S: GOMS, cognitive modeling, graphic layout, textual layout. INTRODUCTION Previous studies have shown GOMS to be a powerful and accurate method of analysis for human performance [e.g., [1, 2]. Despite the wealth of studies that have been performed with GOMS, there has been little or no effort directed towards extending it to model efficiency differences with various graphic and textual layouts. The primary reason for this is because the syntax of GOMS was not sufficiently fine-grained for such differences to become apparent. Recently however, GOMS was expanded to model tasks with low level perceptual, cognitive and motor operators [e.g., 5]. This opens up the possibility of using GOMS to compare different layouts. Such an analysis would be very useful in testing newly developed user interfaces. In addition, it can also be used to provide heuristics and highlight problems in automatic visualization systems. THE TASK We modeled Casner’s task of finding information about airline flights [3,4] In particular, the user had to fiid a pair of connecting flights that travel from Pittsburgh to Mexico City, such that the flights are available, the layover is no longer than four hours, and the combined cost of the flights do not exceed

SageBook: searching data-graphics by content

500. Casner presents four examples of graphical layouts that present the required information: 1) tabular layout, where the rows contain information for Permission to copy without fee all or pert of this material is granted provided that the copies are not made or dktributad for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, end notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republish, requires a fee andior specific permission. CH194 Companion-4/94 Boston, Massachusetts USA e 1994 ACM 0-89791 -651 -4/94 /0323 ..

Managing software with new visual representations

3.50 each flight and the columns represent origin, destination, availability, price, departure time and arrival time; 2) graphical layout that represents individual flights as rectangles on a timeline. Cost and availability is encoded as text inside the rectangles. The right-edge of each rectangle encc~des departure time, the left-edge encodes arrival time and the length of the rectangle encodes flight duration; 3) graphical layout that is similar to (2) but uses shading to incticate availability and finally 4) graphical layout that is similar to (3) but uses the height of the rectangle to indlicate pricel. THE MODEL There are many different strategies for accc)mplishing the task specifkl above. In [3], Casner examines eight different algorithms for the task. These algorithms capture different types of spatial searches but by no means exhaust all possible task methods. A complete analysis of the layouts would try to iclentify and model a reasonable set of all the possible algorithms (as John, et.al. did in [6]) or empirically determine which strategies are actually used, However, to limit the scope of this preliminary analysis, we modeled a single straightforward, efficient algorithm for each layout. We realized these algorithms as a series of GOMS operatcrs that, given the particular task and display, solve the task. In particular, the most important task operation for differentiating between the layouts, the visual search, was modeled with the combinations of cognitive, motor and perceptual operators proposed in [5]. We assigned a duration to each GOMS operator base[i on previous psychological studies [2, 5]. We then added the durations of operators together appropriately to get a zero-parameter prediction of performance time for each display layout. Since previous GOMS modeling did nolt include any guidance for predicting the duration or pattern of visual search that am based on display layout (i~s opposed to functional requirements of the task), we adopled Tunis’ ruleof-thumb that all information grouped within 5 degrees of visual angle can be perceived in a single eye fixation [7]. Assuming that the user was approximately 15 inches from the screen,5 degreesof visual angle is equal to 0.65 inches, which corresponds to approximately six 12 point characters. 1 Layout 4 was constructed by Casner’s automatic visualization system, BOZ.

Toward an information visualization workspace: combining multiple means of expression

Currently, there are many hypertext-like tools and database retrieval systems that use keyword search as a means of navigation. While useful for certain tasks, keyword search is insufficient for browsing databases of data-graphics. SageBook is a system that searches among existing datagraphics, so that they can be reused with new data. In order to fulfill the needs of retrieval and reuse, it provides: 1) a direct manipulation, graphical query interface; 2) a content description language that can express important relationships for retrieving data-graphics; 3) automatic description of stored data-graphics based on their content; 4) search techniques sensitive to the structure and similarity among data-graphics; 5) manual and automatic adaptation tools for altering data-graphics so that they can be reused with new data.

Glyphs for software visualization

Managing large projects is a very challenging task requiring the tracking and scheduling of many resources. Although new technologies have made it possible to automatically collect data on project resources, it is very difficult to access this data because of its size and lack of structure. We present three novel glyphs for simplifying this process and apply them to visualizing statistics from a multi-million line software project. These glyphs address four important needs in project management: viewing time dependent data; managing large data volumes; dealing with diverse data types; and correspondence of data to real-world concepts.