U-M CIS 577 - Software Tools and User Interface Design

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Software Tools and User Interface DesignLecture Slides Based on Usability Engineering by Laventhal and BarnesAnalysisSpecificationContext Setting ActivitiesSpecifying the ProblemWhat is the Process?Understanding User TasksTask Analysis and Specification - 1Task Analysis and Specification - 2Task Analysis and Specification - 3Why is it hard to build a task analysis from scenarios?HintsHow to synthesize...Use CasesWhat Else?User ProfilesLevanthal’s ExampleScenario AnalysisOne ScenarioSample Use Case for ScenarioHigh-level DiagramHigh-level Use Case DiagramHierarchical task AnalysisFirst Two Levels of Hierarchical Task BreakdownRefining the Task AnalysisFurther RefiningHierarchical Breakdown of Task 3.1: Add a new CD to catalogNotes on Task AnalysisTask DescriptionsSlide 31Slides based in Shneiderman’s Designing the User InterfaceSpecification MethodsNatural Language SpecificationsBackus-Naur Form (BNF)Multiparty GrammarsState Transition Diagram for Menu SystemState Transition Diagram with Arc FrequenciesState Chart with State GroupingsInteraction Object GraphFeatures of Interface-Building Tools - 1Features of Interface-Building Tools - 2User Interface Mockup ToolsFlash MXVisual Basic .netJBuilderInterface-Building Tool TradeoffsApplication FrameworkSpecialized language layers01/14/19 1Software Tools and User Interface DesignCIS 577Bruce R. MaximUM-Dearborn01/14/19 2Lecture Slides Based onUsability EngineeringbyLaventhal and Barnes01/14/19 3Analysis•Understanding the context and the details of the problem (i.e., the UI) from the user’s perspective.01/14/19 4Specification•Producing detailed documents that spell out as specifically as possible what the UI for the product will be like.01/14/19 5Context Setting Activities•Understanding and specifying–General usability expectations–Needs and features–Feasibility and constraints•Project Planning and Resource Scheduling01/14/19 6Specifying the Problem•Use case analysis and user profile specifications•Task analysis and specification•Analysis and documentation of usability requirements –E.g., Identification and definition of what “easy to learn” means.01/14/19 7What is the Process? •Sell your idea and determine if it is feasible.–Establish need, expectations and constraints.–Perform a feasibility study to determine if the project is feasible (for you and your customer).•Plan and schedule the project and its resources.•Understand and specify the problem.–Analyze and specify user task requirements.–Analyze user characteristics and generate user profiles.–Analyze and specify usability requirements.01/14/19 8Understanding User Tasks•Strategies–Use case analysis–Analysis of scenarios–Hierarchical task analysis•We need a strategy that combines all three elements.01/14/19 9Task Analysis and Specification - 1•STEP 1. Start with a narrative description of the tasks that the user wishes to accomplish with the proposed user interface. •STEP 2. Look at a number of scenarios describing specific tasks that someone might do with our interface.•STEP 3. For each scenario, build an informal use case diagram.01/14/19 10Task Analysis and Specification - 2•STEP 4. From the collection of informal use case diagrams, we will extract primary entities.•STEP 5. With our informal use case diagrams and models of primary entities, we will consolidate to form a high-level use case diagram that shows what tasks a user might perform with the interface.01/14/19 11Task Analysis and Specification - 3•STEP 6. For each use case, we will perform hierarchical task decomposition (hierarchical task analysis - GOMS).•STEP 7. For each task in each task decomposition, we will develop a multipoint descriptive narrative.•STEP 8. For each task, we will consider any other information that the user has shared.01/14/19 12Why is it hard to build a task analysis from scenarios?•Scenarios are specific.•The tasks in a task analysis are abstract.•The developer must synthesize several specific scenarios into abstract tasks.01/14/19 13Hints•If your task specification is derived from scenarios, here are some rules of thumb:–There should be a mixture of simple and more complex tasks. –Producing an effective set of tasks will be a real test of the designer's understanding of the users and their work. •The specific scenarios can be integrated into descriptions of more abstract tasks.01/14/19 14How to synthesize...•The trick is to identify what is common across scenarios.•We will look at a simple strategy to accomplish this.•Our example problem is “bake a cake.”01/14/19 15Use Cases•Develop a high-level use case model for each scenario showing the tasks that the user performs as indicated by the scenario.•Combine/rebuild the original, scenario-by-scenario use case models into a single, more abstract model.–The actors are aggregates of the roles played by specific users.–The use cases suggest high level tasks for the hierarchical task analysis.01/14/19 16What Else?•Every task should be accompanied by a written description which answers a number of questions.•The answers to these questions will convey critical information to the designer and form an essential part of the problem definition.01/14/19 17User ProfilesDocument user characteristics including•User expertise•User motivation •User feedback about job functions•How the user interface will impact user’s job01/14/19 18Levanthal’s Example•Task is to analyze and derive a specification for a project. •The sample project is to specify and build a user interface for an audio catalog system. •Because we are describing this project, there are no users to interview or observe.01/14/19 19Scenario Analysis•Our project system is described by a set of scenarios.•We need to extract the various entities and tasks from the scenarios.•We adopt use case diagrams to help visualize the entities and tasks.01/14/19 20One Scenario •Client is donating a CD to the Humane Society. •Wants to put a sticky label with the songs on the label. •Wants computerized catalog to do this.•There are two actor roles here: the catalog user and the audio collection.•There is one task: make a label.01/14/19 21Sample Use Case for Scenario01/14/19 22High-level Diagram•After reviewing the various scenarios, we want to extract the major tasks and form a high-level use case diagram.01/14/19


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U-M CIS 577 - Software Tools and User Interface Design

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