业务建模：一种问题分析技术，适合IS/IT环境，有助于定义系统及其应用。
业务用例模型有助于定义系统及其应用，分为业务用例模型（由actor和use case组成，是业务功能的模型）和业务对象模型（描述了提交实现业务用力功能的实体，以及这些实体相互间如何交互）。
业务用例模型：业务预期功能的模型，在机构中确定角色和可提交产品时用作主要输入。
A business use-case model: a model of the intended functions of the business and is used as an essential input to identify roles and deliverables in the organization.
包括：actors(users and systems that interact with the business)和use cases(sequential events through which the actors interact with the business elements to get their jobs done)
业务对象模型：描述了实体（部门、工资、系统）以及他们如何交互完成业务用例所需要的功能。
Business object model: describes the entities----departments, paychecks, systems----and how they interact to deliver the functionality necessary to realize the business use cases.
系统工程（system engineering）是一种问题分析技术，特别是用于嵌入式系统开发
自上而下的需求细化(Requirements flowdown) is primarily a matter of ensuring that all system requirements are filled by a subsystem or a set of subsystems collaborating.
几个面向对象的原则：encapsulation, information hiding, interface by contract, messaging rather than data hiding.
问题分析技术：
1， Gain agreeement on the problem definition.
2， Understand the root causes of the problem.
3， Identify the stakeholders and the users whose collective judgment will ultimately determine the success or failure of your system.
4， Determine where the boundaries of the solution are likely to be found.
5， Understand the constraints that will be imposed on your team and on the solution.
Searchking for requirements is like searching for ”Undiscovered Ruins”; the more your find, the more you know remain.
激发出用户需求的方法：（1）storyboarding, (2)role playing (3)throwaway prototypes
系统的特性最好限制在25—99，最好要少于50
任意复杂度的系统都可以用一个25—99个特性的表来定义
涉众的需要needs定义：
Reflection of the business, personal, or operational problem(or opportunity) that must be addressed in order to justify consideration, purchase, or use of a new system.
什么是特性：Feature
a service the system provides to fulfill one or more stakeholder needs.
什么是属性：attributes:
data elements that provides additional information about the feature.
面谈：最主要的需求获取方法。
Eliciting requirements的最有力手段：requirements workshop
准备：（1）Selling the concept(the workshop’s benefits)
(2)Ensuring the participation of the right stakeholders.
(3)Attending to logistics. 正规的看待workshop,对stakeholders的邀请和组织都要做好。
(4)Providing warm-up materials
推荐包括两种：
1， Project-specific information.(drafts of requirements documents, bulleted lists of suggested features, copies of interviews with prospective users, analyst’s reports on trends in the industry, letters from customers, bug reports from the existing system, new management directives, new marketing data)
2， Out-of-box thinking preparation.
Simply bring your insights on the features of this new project.
Idea reduction:
(1) prune the ideas that are not worthy of further invest.
(2) Grouping ideas. Group the similar ideas, and name the groups of related ideas.
比如：new Features, performance issues, enhancements to current features, user interface and ease-of-use issues
分组的标准可以基于：系统的能力，以及对不同用户的支持方式
此时，可以重新提出意见
(3) defining features. 要求主意的提出者对提出的意见给出一句话的描述
(4) Prioritizing ideas.
使用的方法（1）cumulative voting -----the hundred-dollar test(can only be applied once)
(2) critical, important, useful categorization.
情节串联板：主要用来得到用户的反映，用以激发用户早的”yes, but…”反映。
Storyboard 分为三类：
Passive : tell a story to user.
Active: a movie that hasn’t actually been produced yet.
Interactive: let the user experience the system in as realistic a manner as practical.
用例入门：
use case: describes sequences of actions a system performs that yield an observable result of value to a particular actor.
Sequences of actions: describes a set of functions performed, algorithmic procedure, any other internal process that produces a result.
An action is atomic.
System performs: The system works for the actor.
An observable result of value: a most important construct.
A particular actor: (someone or something that interacts with the system)is individual or device that initiates the action.
三种类型的actior：users(用户)，other systems or applications(其他系统或应用程序)，device(设备)
用例模版：
Name of the use caseDescription: The purpose of the use case should be described in one or two sentences.
Actor(s):列出使用该用例的所有actor
Flow of events:对actor与system之间如何交互做出的文字描述
Basic flow
Event1
Event2
Alternate flow
Pre-conditions：通常表示用例使用之前，系统必须处于的状态
Post-conditions：描述了当系统运行完某个用例时所处于的状态。（通常代表用例完成后一些状态作为永久数据的保存）
Other stakeholders: key stakeholders affected by the use case.
Special Requirements:
