Outlook on Technical Contributions of this Thesis

In the remainder of this chapter, we provide an outlook on the technical contributions presented in the following chapters. These chapters address the six technical challenges identified in Section3.1. They serve as proof of concepts for the applicability of our design methodology presented in Section3.2. We categorize the underlying decision scenarios according to our domain characterization. Three of them target textual data, one addresses empirical data, and the last two tackle model-driven data. We also discuss which general decision making tasks are supported by the respective visual analytics system and which stakeholder have been involved in the design process.

Visual-Interactive Access to Decision Making Processes

In Chapter4, we address the process overview challengeCProc, presenting a visual analytics system for the creation, exploration, and analysis of decision-related content. The visual analytics system orga-nizes relevant text documents in a timeline visualization that we named ‘PolicyLine’. Documents can be distinguished based on their publication date, title, author category, and relevance to the decision process. Users are enabled to create new processes including the definition of process step, or aug-ment existing processes with additional docuaug-ments, docuaug-ment ratings, and comaug-ments on docuaug-ments.

Automatic analysis methods calculate the likelihood of alternative solutions (represented by specific documents) to succeed. In the design process, decision makers, analysts, and domain experts were involved. The contributions of this chapter are: (1) a problem characterization about providing deci-sion making process overviews, (2) a visual analytics system for the text document-driven overview of the decision process, and (3) a design study including three cycles of design, implementation, and evaluation conducted with eighteen real-world users.

Figure 3.10.:PolicyLine: visualizing the decision process. Presented in Chapter4.

3.4. Outlook on Technical Contributions of this Thesis

Visual-Interactive Access to Text Document Collections

In Chapter5, we demonstrate a visual analytics system for providing content-based overviews of text document collections and solve challenge CDoc. Text clustering as a method of choice is applied to condense large numbers of documents to a small set of representatives. The visual analytics system provides visual and interactive access to the entire text clustering process from the pre-processing of unstructured text documents, the selection of features for representing documents, and the parameter-ization and computation of text clusterings to the comparison of different clustering results and their validation. Due to the complexity of text clustering in general, and the provided degrees of freedom in the interaction design of our visual analytics approach, the system is targeting analyst as primary users.

Nevertheless, the results generated with the system can be used to provide content-based overviews to decision makers and other stakeholders in the process. The contributions of this chapter are: (1) a visual and interactive interface for the selection of a feature vector representation required for the clustering text documents, (2) a visual and interactive interface for the creation and analysis of text clusterings adapted to the specific data, users, and task at hand, and (3) a visual and interactive inter-face for the comparison of different text clusterings that allows users to choose the most appropriate clustering result for the specific data, users, and task at hand.

Figure 3.11.:Content-based exploration and analysis of text document collections. Presented in Chapter5.

Visual-Interactive Access to Online Debates

In Chapter6, we present a visual analytics system for aggregating textual content extracted from public debates in social media channels, which addresses challenge CDeb. The system provides visual and interactive access to text segments extracted from the web and mapped to pre-defined policy models and arguments. In addition, the sentiment of text segments is extracted and shown to the user. The system allows users to monitor the public debate on specific topics and identify new arguments that may inform the decision process. In addition, the user is enabled to refine the underlying model by providing feedback on the accuracy of the automatically generated text analysis results. During the design process decision makers, domain experts, analysts, and modeling experts from the text analysis domain were

involved. The contributions of this chapter are: (1) the definition of a text analysis workflow adapted to the specific needs for monitoring the public debate, (2) a visual analytics system that provides visual and interactive access to the results of the text analysis workflow, and (3) a user feedback concept that allows users to improve the accuracy of the text analysis models via user interactions.

Figure 3.12.:Analysis of Arguments and Opinions in Text Documents. Presented in Chapter6.

Visual-Interactive Access to Empirical Datasets

In Chapter7, we address the challenge about the exploration, analysis, and comparison of empirical dataCDat. We introduce a visual and interactive system for accessing country-specific performance indi-cators in the mining sector. The system is designed for governmental and business (investors) decision makers as well as for public stakeholders. Domain experts provided knowledge on the governmental and legal aspects related to mining in resource-rich countries. This knowledge was transformed to qual-itative performance indicators. Our visual analytics system allows stakeholders to get an overview of individual country performances, identify weaknesses and strengths of individual countries, compare the performances of multiple countries, and search for similar countries. As overarching goals, in-vestors are supported in their investment decisions, governments are supported in their policy decisions to improve the current status and attract investments, and public stakeholders are supported in their un-derstanding of political decisions. The contributions of this chapter are (1) a domain characterization of the mining sector as a specific decision making domain, (2) a visual analytics system for providing visual and interactive access to performance indicators, and (3) evaluation results gathered in a user workshop with domain experts from the mining sector.

3.4. Outlook on Technical Contributions of this Thesis

Figure 3.13.:Exploration and Comparison of Mining-Related Empirical Data. Presented in Chapter7.

Visual-Interactive Access to Simulation Models

In Chapter8, we combine simulation techniques with visualization methods to create a visual analytics system supporting the analysis of impacts derived from alternative solutions. This chapter addresses Challenge CImp on the impact assessment of decision options. The visual analytics system provides visual-interactive access to an agent-based simulation model to support political decision makers in the exploration, creation, analysis, and comparison of simulation data. With the agent-based simulation model the impact of alternative governmental subsidy strategies on the public adoption of photovoltaic plants is assessed. Our visual analytics system was designed in collaboration with decision makers, analysts, domain experts in the energy sector, and modeling experts in agent-based simulation. The contributions of the chapter are (1) a problem characterization of simulation applied to policy making in the energy sector, (2) a visual-interactive interface for the impact assessment of alternative solutions via an agent-based simulation model, (3) a novel visualization technique specialized on the exploration of dependencies between input and output variables.

Figure 3.14.:Simulating the Impact of Decision Options. Presented in Chapter8.

Visual-Interactive Access to Optimization Models

Finally, in Chapter9, we combine visualization methods with optimization techniques to create a vi-sual analytics system that supports the balancing of trade-offs, and in consequence, the generation of optimal solutions for a given problem. This chapter addresses ChallengeCOpton the creation, analysis, and comparison of optimal solutions. The optimization model enables analysts and decision makers to define an optimal energy plan based on a pre-defined target function and constraints considering environmental and economic factors. The visual analytics system was designed and evaluated in col-laboration with political decision makers, analysts, domain experts, and optimization modeling experts.

The contributions of the chapter are (1) a problem characterization on the strategic environmental as-sessment (SEA) domain targeting the development of sustainable policy decisions, (2) a visual analytics system combining visualization and optimization techniques to support the generation of optimal re-gional energy plan, and (3) the results of two user evaluation rounds conducted with two intermediate versions of the system.

Figure 3.15.:Balancing Trade-Offs with Optimization Models. Presented in Chapter9.

4. Visual-Interactive Access to the Decision