软件设计是将用户需求转化为某种合适形式的过程，它帮助程序员进行软件编码和实现。在软件设计阶段，根据 SRS 文档中记录的客户要求生成设计文档。因此，此阶段的目标是将 SRS 文档转换为设计文档。
在设计阶段设计并记录了以下项目：
需要不同的模块。
控制模块之间的关系。
不同模块之间的接口。
不同模块之间的数据结构。
在各个模块之间实现所需的算法。
软件设计的目标：
正确性：
一个好的设计应该是正确的，即它应该正确地实现系统的所有功能。
效率：
一个好的软件设计应该解决资源、时间和成本优化问题。
可理解性：
一个好的设计应该是易于理解的，它应该是模块化的，并且所有模块都分层排列。
完整性：
设计应包含所有组件，如数据结构、模块和外部接口等。
可维护性：
每当客户提出更改请求时，一个好的软件设计应该很容易更改。
软件设计分为三个不同层次。他们是：
架构设计：
系统的架构可以被视为系统的整体结构以及结构提供系统概念完整性的方式。架构设计将软件识别为具有许多相互交互的组件的系统。在这个级别上，设计人员了解了提议的解决方案域的想法。
初步或高层设计：
这里将问题分解为一组模块，识别出各个模块之间的控制关系，也识别出各个模块之间的接口。这个阶段的结果称为程序架构。这个阶段使用的设计表示技术是结构图和UML。
详细设计： 一旦完成高级设计，就会进行详细设计。在详细设计中，每个模块都经过仔细检查以设计数据结构和算法。阶段结果以模块规范文档的形式记录。
Computing and Information Systems 代考案例
Q1
a. Define “representation gap” and explain its importance in software design
b. Define “refactoring” and explain its importance in agile development
a. Define “representation gap” and explain its importance in software design
b. Define “refactoring” and explain its importance in agile development
a. Define “representation gap” and explain its importance in software design
b. Define “refactoring” and explain its importance in agile development
a. Define “representation gap” and explain its importance in software design b. Define “refactoring” and explain its importance in agile development
Q2
List two elements present in UML design class diagrams but not present in UML domain class diagrams. For each, explain what the element is and why it should not appear in a domain class diagram.
Q3
“There is no point commencing design until we have a complete set of use cases, a complete domain model and a full set of system sequence diagrams”. Is this ever a valid position to take? What is the alternative? Discuss.
Q4
Describe the purpose of UML sequence diagrams and UML communication diagrams, explain how they differ, and provide reasons why you might choose one over the other.
Q5
Describe protected variations, variation points, evolution points, and the role they play in the tradeoff between brittle and overly generalized designs.
Q6 This question relates to the following domain model. This is the iteration-3 domain model for the Monopoly case study from Applying UML and Patterns, 3rd Ed. by Larman.
Below is a list of changes to the Monopoly game. For each change, describe precisely or draw the corresponding change (if any) that should be made to the Monopoly domain diagram. You should not redraw the whole diagram.
a. A new move rule is introduced. If a Player P is about to move their Piece to a Square, and there is already another Player’s Piece on that Square, Player P will instead move their Piece to the next Square without a Piece already on it.
b. One of the Railroad Property Squares is replaced by another Income Tax Square.
c. A new kind of square called a Park is created; there are four different Parks. Every Player is required to choose their favourite Park at the start of the game (they can choose the same Park if they wish).
d. For this change you should assume that (i) all turns (whoever’s turn it is) are numbered in sequence starting with 1, and (ii) Properties can be bought and sold by Players, and once a Property has been bought, it will always be owned by some Player. New rules are introduced that depend on knowing for which turns a particular Player owned a Property. An example of such a rule is: a previous owner of a Property who lands on that Property gets a discount on rental based on the total number of turns for which they owned the property. Note that the simple existing concept of ownership should not get lost in your proposed changes.
