Rethinking map legends with visualization

This design paper presents new guidance for creating map legends in a dynamic environment. Our contribution is a set of guidelines for legend design in a visualization context and a series of illustrative themes through which they may be expressed. These are demonstrated in an applications context through interactive software prototypes. The guidelines are derived from cartographic literature and in liaison with EDINA who provide digital mapping services for UK tertiary education. They enhance approaches to legend design that have evolved for static media with visualization by considering: selection, layout, symbols, position, dynamism and design and process. Broad visualization legend themes include: The Ground Truth Legend, The Legend as Statistical Graphic and The Map is the Legend. Together, these concepts enable us to augment legends with dynamic properties that address specific needs, rethink their nature and role and contribute to a wider re-evaluation of maps as artifacts of usage rather than statements of fact. EDINA has acquired funding to enhance their clients with visualization legends that use these concepts as a consequence of this work. The guidance applies to the design of a wide range of legends and keys used in cartography and information visualization.     

Effects of video placement and spatial context presentation on path reconstruction tasks with contextualized videos

Many interesting and promising prototypes for visualizing video data have been proposed, including those that combine videos with their spatial context (contextualized videos). However, relatively little work has investigated the fundamental design factors behind these prototypes in order to provide general design guidance. Focusing on real-time video data visualization, we evaluated two important design factors--video placement method and spatial context presentation method--through a user study. In addition, we evaluated the effect of spatial knowledge of the environment. Participants' performance was measured through path reconstruction tasks, where the participants followed a target through simulated surveillance videos and marked the target paths on the environment model. We found that embedding videos inside the model enabled realtime strategies and led to faster performance. With the help of contextualized videos, participants not familiar with the real environment achieved similar task performance to participants that worked in that environment. We discuss design implications and provide general design recommendations for traffic and security surveillance system interfaces.     

Evaluating early prototypes in context: trade-offs, challenges, and successes

We would like to say that experience prototyping and Wizard of Oz prototyping, taken together, constitute a suitable alternative to true contextual evaluation for early prototypes, one gaining realism at the expense of impartiality, the other impartiality at the expense of realism. As our experiences show, however, each pervasive application design poses unique challenges that you must consider when applying these approaches. Regardless, it's often a good trade-off to sacrifice some measure of realism to evaluate early prototypes. Evaluation of early pervasive computing prototypes in context is a pragmatic exercise, but one that is nonetheless informed by general approaches that reflect and adapt to the challenges of pervasive application development.     

Using Visualization to Explore Original and Anonymized LBSN Data

We present GSUVis, a visualization tool designed to provide better understanding of location‐based social network (LBSN) data. LBSN data is one of the most important sources of information for transportation, marketing, health, and public safety. LBSN data consumers are interested in accessing and analysing data that is as complete and as accurate as possible. However, LBSN data contains sensitive information about individuals. Consequently, data anonymization is of critical importance if this data is to be made available to consumers. However, anonymization commonly reduces the utility of information available. Working with privacy experts, we designed GSUVis a visual analytic tool to help experts better understand the effects of anonymization techniques on LBSN data utility. One of GSUVis's primary goals is to make it possible for people to use LBSN data, without requiring them to gain deep knowledge about data anonymization. To inform the design of GSUVis, we interviewed privacy experts, and collected their tasks and system requirements. Based on this understanding, we designed and implemented GSUVis. It applies two anonymization algorithms for social and location trajectory data to a real‐world LBSN dataset and visualizes the data both before and after anonymization. Through feedback from domain experts, we reflect on the effectiveness of GSUVis and the impact of anonymization using visualization.     

Virtual Video Prototyping

Computing power is an integrated part of our physical environment, and since our physical environment is three-dimensional, the virtual studio technology, with its unique potential for visualizing digital 3D objects and environments along with physical objects, offers an obvious path to pursue in order to envision future usage scenarios in the domain of pervasive computing.We label the work method virtual video prototyping, which grew out of a number of information systems design techniques along with approaches to visualization in the field of architecture and set design.We present a collection of virtual video prototyping cases and use them as the platform for a discussion, which pinpoint advantages and disadvantages of working with virtual video prototyping as a tool for communication, experimentation and reflection in the design process. Based on more than ten cases we have made the observations that virtual video prototypes 1) are a powerful medium of communication in development teams and for communication with industry partners and potential investors, 2) support both testing and generating ideas 3) are particular suited for addressing spatial issues and new ways of interacting. In addition practical use of virtual video prototypes has indicated the need to take into account some critical issues including a) production resources, b) hand-on experience, and c) the seductive power of virtual video prototypes.     

Design Factors for Summary Visualization in Visual Analytics

Data summarization allows analysts to explore datasets that may be too complex or too large to visualize in detail. Designers face a number of design and implementation choices when using summarization in visual analytics systems. While these choices influence the utility of the resulting system, there are no clear guidelines for the use of these summarization techniques. In this paper, we codify summarization use in existing systems to identify key factors in the design of summary visualizations. We use quantitative content analysis to systematically survey examples of visual analytics systems and enumerate the use of these design factors in data summarization. Through this analysis, we expose the relationship between design considerations, strategies for data summarization in visualization systems, and how different summarization methods influence the analyses supported by systems. We use these results to synthesize common patterns in real‐world use of summary visualizations and highlight open challenges and opportunities that these patterns offer for designing effective systems. This work provides a more principled understanding of design practices for summary visualization and offers insight into underutilized approaches.     

Remembering today tomorrow: Exploring the human-centred design of digital mementos

This paper describes two-part research exploring the context for and human-centred design of ‘digital mementos’, as an example of technology for reflection on personal experience (in this case, autobiographical memories). Field studies into families' use of physical and digital objects for remembering provided a rich understanding of associated user needs and human values, and suggested properties for ‘digital mementos’ such as being ‘not like work’, discoverable and fun. In a subsequent design study, artefacts were devised to express these features and develop the understanding of needs and values further via discussion with groups of potential ‘users’. ‘Critical artefacts’ (the products of Critical Design) were used to enable participants to envisage broader possibilities for social practices and applications of technology in the context of personal remembering, and thus to engage in the design of novel devices and systems relevant to their lives. Reflection was a common theme in the work, being what the digital mementos were designed to afford and the mechanism by which the design activity progressed. Ideas for digital mementos formed the output of this research and expressed the designer's and researcher's understanding of participants' practices and needs, and the human values that underlie them and, in doing so, suggest devices and systems that go beyond usability to support a broader conception of human activity.     

An intelligent assistant for requirements validation

The process of determining user requirements for software systems is often plagued with uncertainty, ambiguity, and inconsistency. Rapid prototyping offers an iterative approach to requirements engineering that can be used to alleviate some of the problems with communication and understanding. Since the systems development process is characterized by changing requirements and assumptions, involving multiple stakeholders with often differing viewpoints, it is beneficial to capture the justifications for the decisions in the development process in a structured manner. Thisdesign rationale captured during requirements engineering can be used in conjunction with the rapid prototyping process to support various stakeholders involved in systems development. CAPS (the Computer Aided Prototyping System) has been built to help software engineers rapidly construct prototypes of proposed software systems. REMAP (Representation and MAintenance of Process knowledge) provides a conceptual model and mechanisms to represent and reason with (design) rationale knowledge. In this paper, we describe how in the context of evolving requirements, the CAPS system augmented with REMAP helps firm up software requirements through iterative negotiations via examination of executable prototypes and reasoning with design rationale knowledge.     

An initial industrial evaluation of interactive search-based testing for embedded software

Search-based software testing promises the ability to generate and evaluate large numbers of test cases at minimal cost. From an industrial perspective, this could enable an increase in product quality without a matching increase in the time and effort required to do so.Search-based software testing, however, is a set of quite complex techniques and approaches that do not immediately translate into a process for use with most companies.For example, even if engineers receive the proper education and training in these new approaches, it can be hard to develop a general fitness function that covers all contingencies. Furthermore, in industrial practice, the knowledge and experience of domain specialists are often key for effective testing and thus for the overall quality of the final software system. But it is not clear how such domain expertise can be utilized in a search-based system.This paper presents an interactive search-based software testing (ISBST) system designed to operate in an industrial setting and with the explicit aim of requiring only limited expertise in software testing. It uses SBST to search for test cases for an industrial software module, while also allowing domain specialists to use their experience and intuition to interactively guide the search.In addition to presenting the system, this paper reports on an evaluation of the system in a company developing a framework for embedded software controllers. A sequence of workshops provided regular feedback and validation for the design and improvement of the ISBST system. Once developed, the ISBST system was evaluated by four electrical and system engineers from the company (the ‘domain specialists’ in this context) used the system to develop test cases for a commonly used controller module. As well as evaluating the utility of the ISBST system, the study generated interaction data that were used in subsequent laboratory experimentation to validate the underlying search-based algorithm in the presence of realistic, but repeatable, interactions.The results validate the importance that automated software testing tools in general, and search-based tools, in particular, can leverage input from domain specialists while generating tests. Furthermore, the evaluation highlighted benefits of using such an approach to explore areas that the current testing practices do not cover or cover insufficiently.     

User-centred app design for speech sound disorders interventions with tablet computers

Traditional speech and language pathology practice (SLPP) faces challenges delivering effective and timely therapy due to long waiting lists, the need for regular practice outside the clinic and a lack of children’s motivation to engage in persistent practice. Technology has untapped potential to address these issues and improve SLPP. This paper describes the design of a tablet app for delivering technology-enhanced therapy for children with speech sound disorders and investigates the impact of the use of apps on SLPP. The initial design was informed by a nation-wide survey of speech-language pathologists (SLPs). The quantitative analysis disclosed that even though SLPs positively perceive mobile technology, they do not currently fully exploit it in their practice due to a lack of apps in their native language and the limited usefulness of apps in foreign languages. Using a user-centred design process, a multidisciplinary team created three prototypes and a final version of an app that has been tested in real therapeutic sessions during everyday practice and informed by feedback from SLPs and children. The observation analysis is presented based on an adaptation of Koole’s FRAME model. The qualitative findings indicate that SLPs identify mobile apps as enabling greater mobility, allowing new therapeutic approaches, creating possibilities for practice outside the therapeutic setting and increasing children’s motivation, supporting greater persistence to practise in the context of the therapy.     

Using sketches and storyboards to assess impact of age difference in user experience

We compared two versions of a touch-screen digital thermostat using a framework encompassing several user experience (UX) characteristics, and here describe how the implementation of certain design factors (specialists, praises, tooltips and increased interactivity) was done on mixed-fidelity prototypes of the user interface. We illustrate how the experimental comparison, involving 20 university students and 20 older adults, revealed important differences in UX, including perceived ease of use, behavioral intentions, enjoyment, quality, satisfaction, trust and usability, measured mainly through established questionnaires.Analysis revealed that using that kind of artifacts is a very cost effective way to elicit interesting and useful results; many UX variables are significantly affected by design factors and by age differences, as expected; effects of design factors go well beyond usability and therefore could not be caught by running an investigation focused only on usability.Age difference matters: older adults do not respond to addition of specialists, praises and tooltips as younger users do. We argue that potential benefits of these design choices are outweigh by the increase in complexity of the user interface.From a methodological viewpoint we suggest using a particular array of UX characteristics and metrics when testing mixed-fidelity prototypes. Not all the metrics that we adopted were equally useful, and in particular perceived usability, subjective mental effort, and emotions did not help us highlighting differences.     

A self-organizing map for transactional data and the related categorical domain

After projecting high dimensional data into a two-dimension map via the SOM, users can easily view the inner structure of the data on the 2-D map. In the early stage of data mining, it is useful for any kind of data to inspect their inner structure. However, few studies apply the SOM to transactional data and the related categorical domain, which are usually accompanied with concept hierarchies. Concept hierarchies contain information about the data but are almost ignored in such researches. This may cause mistakes in mapping. In this paper, we propose an extended SOM model, the SOMCD, which can map the varied kinds of data in the categorical domain into a 2-D map and visualize the inner structure on the map. By using tree structures to represent the different kinds of data objects and the neurons’ prototypes, a new devised distance measure which takes information embedded in concept hierarchies into consideration can properly find the similarity between the data objects and the neurons. Besides the distance measure, we base the SOMCD on a tree-growing adaptation method and integrate the U-Matrix for visualization. Users can hierarchically separate the trained neurons on the SOMCD's map into different groups and cluster the data objects eventually. From the experiments in synthetic and real datasets, the SOMCD performs better than other SOM variants and clustering algorithms in visualization, mapping and clustering.     

A Survey on Visual Analysis Approaches for Financial Data

Market participants and businesses have made tremendous efforts to make the best decisions in a timely manner under varying economic and business circumstances. As such, decision‐making processes based on Financial data have been a popular topic in industries. However, analyzing Financial data is a non‐trivial task due to large volume, diversity and complexity, and this has led to rapid research and development of visualizations and visual analytics systems for Financial data exploration. Often, the development of such systems requires researchers to collaborate with Financial domain experts to better extract requirements and challenges in their tasks. Work to systematically study and gather the task requirements and to acquire an overview of existing visualizations and visual analytics systems that have been applied in Financial domains with respect to real‐world data sets has not been completed. To this end, we perform a comprehensive survey of visualizations and visual analytics. In this work, we categorize Financial systems in terms of data sources, applied automated techniques, visualization techniques, interaction, and evaluation methods. For the categorization and characterization, we utilize existing taxonomies of visualization and interaction. In addition, we present task requirements extracted from interviews with domain experts in order to help researchers design better systems with detailed goals.     

Digital assessment in higher education

Statistics show there is a clear relationship between higher education and employment in Norway, especially for people with disabilities. The use of digital assessment solutions is increasing in Norwegian higher education. The overall goal of this study is therefore to highlight the potential for improvement of current practices related to universal design, both for providers of digital assessment solutions and for higher education institutions. Based on a case study of practices in Norwegian higher education sector, this article reviews existing requirements for ensuring universal design in digital assessment solutions, prototypes an approach to evaluating universal design quality (UD-Q) of two major Norwegian digital assessment solutions and investigates the compliance between providers’ self-assessments from interviews and UD-Q evaluation scores. The article presents two contributions: (1) an improved set of requirements for universal usability when procuring digital assessments solutions and (2) UD-Q, a stepwise feature analysis-based expert inspection method for evaluating the UD-Q of digital assessment solutions.     

PAVED: Pareto Front Visualization for Engineering Design

Design problems in engineering typically involve a large solution space and several potentially conflicting criteria. Selecting a compromise solution is often supported by optimization algorithms that compute hundreds of Pareto-optimal solutions, thus informing a decision by the engineer. However, the complexity of evaluating and comparing alternatives increases with the number of criteria that need to be considered at the same time. We present a design study on Pareto front visualization to support engineers in applying their expertise and subjective preferences for selection of the most-preferred solution. We provide a characterization of data and tasks from the parametric design of electric motors. The requirements identified were the basis for our development of PAVED, an interactive parallel coordinates visualization for exploration of multi-criteria alternatives. We reflect on our user-centered design process that included iterative refinement with real data in close collaboration with a domain expert as well as a summative evaluation in the field. The results suggest a high usability of our visualization as part of a real-world engineering design workflow. Our lessons learned can serve as guidance to future visualization developers targeting multi-criteria optimization problems in engineering design or alternative domains.     

Catching two rabbits: adaptive real‐time support for embedded Linux

The trend of digital convergence makes multitasking common in many digital electronic products. Some applications in those systems have inherent real‐time properties, while many others have few or no timeliness requirements. Therefore the embedded Linux kernels, which are widely used in those devices, provide real‐time features in many forms. However, providing real‐time scheduling usually induces throughput degradation in heavy multitasking due to the increased context switches. Usually the throughput degradation becomes a critical problem, since the performance of the embedded processors is generally limited for cost, design and energy efficiency reasons. This paper proposes schemes to lessen the throughput degradation, which is from real‐time scheduling, by suppressing unnecessary context switches and applying real‐time scheduling mechanisms only when it is necessary. Also the suggested schemes enable the complete priority inheritance protocol to prevent the well‐known priority inversion problem. We evaluated the effectiveness of our approach with open‐source benchmarks. By using the suggested schemes, the throughput is improved while the scheduling latency is kept same or better in comparison with the existing approaches. Copyright © 2008 John Wiley & Sons, Ltd.     

面向领域的简化的快速需求分析方法

简化的面向领域的快速原型法，面向特定领域，根据数据库应用的特点，将需求分析分为两个阶段，采用建立某个特殊领域的需求分析的参考原型集的方法，简化了作为需求分析工具的系统原型的建设，这些面向特定领域的参考原型能够协助设计人员在需求分析阶段更好地完成需求采集工作，同时它们又是可进化的原型，经过反复修改使用，其表达能力将不断增强，将有效地节省同类系统开发的时间和费用，降低系统开发的风险。在这些简易、快速的原型基础上进行需求分析，大大地提高了需求分析的效率和准确性。     

Another move toward the minimum consistent subset: a tabu searchapproach to the condensed nearest neighbor rule

This paper presents a new approach to the selection of prototypes for the nearest neighbor rule which aims at obtaining an optimal or close-to-optimal solution. The problem is stated as a constrained optimization problem using the concept of consistency. In this context, the proposed method uses tabu search in the space of all possible subsets. Comparative experiments have been carried out using both synthetic and real data in which the algorithm has demonstrated its superiority over alternative approaches. The results obtained suggest that the tabu search condensing algorithm offers a very good tradeoff between computational burden and the optimality of the prototypes selected.