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In computing, a scenario is a narrative of foreseeable interactions of user roles (known in the Unified Modeling Language as 'actors') and the technical system, which usually includes computer hardware and software. A scenario has a goal, which is usually functional. A scenario describes one way that a system is or is envisaged to be used in the context of activity in a defined time-frame. The time-frame for a scenario could be (for example) a single transaction; a business operation; a day or other period; or the whole operational life of a system. Similarly the scope of a scenario could be (for example) a single system or piece of equipment; an equipped team or department; or an entire organization. Scenarios are frequently used as part of the system development process. They are typically produced by usability or marketing specialists, often working in concert with end users and developers. Scenarios are written in plain language, with minimal technical details, so that stakeholders (designers, usability specialists, programmers, engineers, managers, marketing specialists, etc.) can have a common example which can focus their discussions. Increasingly, scenarios are used directly to define the wanted behaviour of software: replacing or supplementing traditional functional requirements. Scenarios are often defined in use cases, which document alternative and overlapping ways of reaching a goal.〔Alexander and Beus-Dukic, 2009. Page 120〕 ==Types of scenario in system development== Many types of scenario are in use in system development. Alexander and Maiden〔Alexander and Maiden, 2004. Chapter 1.〕 list the following types: * Story: "a narrated description of a causally connected sequence of events, or of actions taken".〔 Brief User stories are written in the Agile style of software development.〔Cohn, 2004.〕 * Situation, Alternative World: "a projected future situation or snapshot". This meaning is common in planning, but less usual in software development.〔 * Simulation: models to explore and animate 'Stories' or 'Situations', to "give precise answers about whether such a scenario could be realized with any plausible design" or "to evaluate the implications of alternative possible worlds or situations".〔 * Storyboard: a drawing, or a sequence of drawings, used to describe a user interface or to tell a story. This meaning is common in Human–computer interaction to define what a user will see on a screen.〔 * Sequence: a list of interactive steps taken by human or machine agents playing system roles. The many forms of scenario written as sequences of steps include Operational Scenarios, Concepts of Operations, and Test Cases.〔 * Structure: any more elaborately-structured representation of a scenario, including Flowcharts, UML/ITU 'Sequence Charts', and especially in software development Use cases.〔 Negative scenarios or misuse cases may be written to indicate likely threats which should be countered to ensure that systems have sufficient security, safety, and reliability. These help to discover non-functional requirements.〔Alexander and Maiden, 2004. Chapter 7.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Scenario (computing)」の詳細全文を読む スポンサード リンク
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