3 software product design context ch3

8/2/2019 3 Software Product Design Context Ch3

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Software Design II

Slides modified from: Introduction to Software Engineering Design(C. Fox)

Software Product Design

Context and Analysis


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Context of Software Product Design


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Objectives

To explain how markets influence product types,which in turn influence design

To explain the product planning process

To describe the role and contents of a projectmission statement

To list the variety of software requirements

specificationsTo describe the role and contents of an SRS


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Markets

Organizations study markets to

Choose which markets to sell to (target markets)

Choose what products to develop

Determine product features and characteristics

Amarket is a set of actual or prospectivecustomers who need or want a product,

have the resources to exchange something

of value for it, and are willing to do so.


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Product Categories

A product category is a dimension along whichproducts may differ, for example Target market size

Product line novelty Technological novelty

Product categories help managers Choose target markets

Choose products to develop

Choose product characteristics

A products place in a category influences itsdesign specifications and the design process


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Product Plans

Management must decide which products todevelop.

This decision is documented in a product

plan.

Aproduct plan is a list ofapproved development projects,

with start and delivery dates.


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Product Planning Process

IdentifyOpportunities

Evaluate & PrioritizeOpportunities

Allocate Resources &Determine Timing

Product Planning ProcessProduct Plan : Plan

ProductPlan


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Identifying Opportunities

New product ideas come from Customers

Developers

Entrepreneurs

Marketers

An opportunity funnel is a mechanisms for collectingproduct ideas from diverse sources.

Passive channels

Active channelsAn opportunity statement is a brief description of aproduct development idea.


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The Aqualush Product Opportunity

Lets look at a product that we will keep goingback to in the course as an example forSoftware Design.

Create an irrigation system that uses soil moisturesensors to control the amount of water used.


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Evaluating and Prioritizing Opportunities

Management chooses to pursue opportunitiesbased on Competitive strategy

Technology leaders, low-cost suppliers, customer support.

Market segmentation

Technology trajectories

Software reuse It is easier to develop software from existing parts.

Profitability

Managers attempt to form a well-balanced andcomplete product portfolio.


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Allocating Resources and Determining Timing

Usually there are more good opportunities thanan organization can afford to pursue.

Resources available for development are

analyzed to determine which product to develop.Resource availability also determines the starttime and duration or projects.

The result is a product plan.


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Project Mission Statement

A project mission statement

Launches a development project

States the software design problem

The project mission statement is the main inputto the product design process.

Aproject mission statement is adocument that defines a development

projects goals and limits.


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Project Mission Statement Template

1. Introduction2. Product Vision and Project Scope

3. Target Markets4. Stakeholders5. Assumptions and Constraints6. Business Requirements


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Project Mission Statement - Introduction

The introduction contains backgroundinformation to provide context.

Lets read the Aqualush Mission Statement

(Figure 3-3-3 in the textbook)


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Project Mission Statement - Vision

A product vision statement is a general description of theproducts purpose and form.As an example, the Aqualush Project Mission Statementwas a modification from the Aqualush OpportunityStatement

Create an irrigation system that uses soil moisturesensors to control the amount of water used.

The Aqualush Irrigation System will use soil sensorsto control irrigation, thus saving money forcustomers and making better use of waterresources.


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Project Mission Statement Vision (Major Features List)

The Vision statement may contain a majorfeatures list and should not limit the designers totheir choice of solutions.

Monitor water usage and limit usage to amountsset by users

Allow users to specify times when irrigation occurs Be operated from a simple central control panel Have a Web-based simulator


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Project Mission Statement - Scope

The project scope is the work to be done on aproject.

Often only part of the product vision.

May list what will not to be done as well as what willbe done.

The current project will create the minimal

hardware and software necessary to field a viableproduct along with a Web-based product simulatorfor marketing the product.


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Target Market and Stakeholders

A stakeholder is anyone affected by a product orinvolved in or influencing its development.

Product users and purchasers

Developers and their managers

Marketing, sales, distribution, and product supportpersonnel

Regulators, inspectors, and lawyers

Developers must know the target market andstakeholders to build a product satisfyingstakeholders needs.

Lets review the Aqualush stakeholders fig 3-3-8


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Assumptions and Constraints

An assumption is something that developerstake for granted.

Feature of the problem

Examples: target deployment environments,levels of user support

A constraint is any factor that limitsdevelopers.

Restriction on the solution

Examples: cost and time limits, conformance toregulations


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Business Requirements

A business requirement is a statement of a client or developmentorganization goal that a product must meet.

Time, cost, quality, or business results

Should be stated so that it is clear whether it is satisfied(quantitative goals)

Broad goals related to business, not detailed productspecifications

Aqualush must achieve at least 5% target market share within one yearof introduction.Aqualush must establish base irrigation control technology for use in later

products.Aqualush must demonstrate irrigation cost savings of at least 15% peryear over competitive products.The firs version of Aqualush must be brought to market within one year ofthe development project launch.


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Requirements Engineering

Requirements development is the portion ofrequirements engineering concerned with initiallyestablishing requirements (aka product design).

Requirements management is the portion ofrequirements engineering concerned with controllingand propagating requirements changes.

Requirements engineering iscreating, modifying, and managing

requirements over a products lifetime.


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SRS

The SRS should contain A statement of the product design problem

(may cite the mission statement)

A solution to the product design problemAn SRS is the output of the producedesign process.

Asoftware requirements specification(SRS) is a document cataloging all therequirements for a software product.


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Technical Requirements

A technical requirement is a statement of afeature, function, capability, or property that aproduct must have (that is not a businessrequirement). A functional requirement is a statement of how a

program must map program inputs to programoutputs.

A non-functional requirement is a statement that a

software product must have certain properties. A data requirement is a statement that certain data

must be input to, output from, or stored by a product.


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Requirements Taxonomy

Requirements

Business

Technical

Functional

Non-Functional

Data


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Small Exercise

Make up a set of functional, non-functional, anddata requirements for the Aqualush product.

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Levels of Abstraction in Requirements

A user-level requirement is statement abouthow a product must support stakeholders inachieving their goals or tasks.

An operational-level requirement is a

statement about inputs, outputs, operations,characteristics, etc. that a product mustprovide, without reference to physicalrealization.

A physical-level requirement is a statementabout the physical form of a product, itsphysical interfaces, or its data formats.

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Small Exercise

Take the functional, non-functional, and datarequirements that you specified for the Aqualushproduct and categorize them into user,

operational, and physical.

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Interaction Design

Interaction design is the activity of specifyingproducts that people can use effectively andenjoyably.

Dialog designThe dynamics of the interaction

Physical form designThe static characteristicsand appearance of the interface (presentation)

Interaction design should be part of

requirements development.

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SRS Template1. Product Description

1.1 Product Vision1.2 Business Requirements1.3 Users and OtherStakeholders1.4 Project Scope1.5 Assumptions1.6 Constraints

2. Functional Requirements3. Data Requirements4. Non-Functional Requirements5. Interface Requirements

5.1 User Interfaces5.2 Hardware Interfaces5.3 Software Interfaces

http://www.jiludwig.com/Template_Guidance.html

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Summary

Markets influence product development decisions;product types influence product design.

Management performs a product planning process toproduce a product plan listing development projects.

Projects are launched with a project missionstatement that frames the product design problem.

The output of product design is an SRS that containsfunctional, non-functional, and data requirements

stated at several levels of abstraction.An interaction design is an essential part of an SRS.

3 software product design context ch3

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