Planning of a Web site

• Objective: Discussing the strategic issues of Web site engineering process:– Models used for Web site planning– Compare the Web site with software

Engineering– Web site planning process– Technical issues of Web site planning

Why Modelling?

• Modeling is aimed at providing a specification of a system to be built in a degree of detail sufficient for that system’s implementation.

• The result of a modeling process are models representing the relevant aspects of the system in a simplified and – ideally- comprehensible manner.

Model Fundamentals

• Scope of modeling spans along three orthogonal dimensions.– The first dimension traditionally comprises the

application logic level and the user interface level in the sense of “what” and “how” of an application

– The second dimension concerning structure (i.e. objects, their attributes, and their relations to other objects) and behaviour (i.e., functions and processes) of both user interface and application logic.

– The third dimension refers to the development phases, that means that all the application has to be gradually refined and expanded during the development prcess.

Modeling Specifics in Web Engineering

• Levels: To model Web applications, the document-like character of its content as well as its non-liner hypertext navigation has to be taken into account– Content: The information and application logics underneath the Web

application– Hypertext: The structuring of the content into nodes and links between

these nodes– Presentation: The user interface or page layout

• A clear separation of these three levels allows reuse and helps to reduce complexity

Modeling Specifics in Web Engineering

• Aspects– Structure and behavior are modeled at each of the three levels.– The relevance of the structure and behavior models depends on

the type of Web application to be implemented.• Static Web require less behavior modeling • Dynamic Web such as e-commerce Website with search engines

etc. require more behavior modeling

• Phases– Depending on the type of Web application, it should be possible

to pursue an information-driven approach, i.e., starting with content modeling, or

– A presentation-driven approach, i.e., starting with modeling of the application’s presentation aspects.

Modeling Specifics in Web Engineering

• Customization– The inclusion of context information in the

development of Web applications plays a significant role to allow for e.g. personalization, multi-delivery and location-based services.

– It considers the context, e.g., users’ preferences, device characteristics, or bandwidth restrictions, and allows to adapt the Web application accordingly.

– It influences all three Web modeling dimensions of content, hypertext, and presentation with respect ot structure and behavior and should be taken into account in all phases of the development process.

What should be modeled?• Modeling Requirements• Content Modeling

– Objectives– Concepts

• Hypertext Modeling– Objectives– Hypertext Structure Modeling Concept– Access Modeling Concepts– Relation to Content Modeling

• Presentation Modeling– Objectives– Concepts– Relation to Hypertext Modeling

• Customization Modeling

Models Used for Web Site (Software) Planning

• Waterfall model Distinctive stages, limited interactionStandard Approaches of Waterfall Model:

• Document System Concept • Identify System Requirements and Analyze Them • Break the System into Pieces (Architectural Design) • Design Each Piece (Detailed Design) • Code the System Components and Test Them

Individually (Coding, Debugging, and Unit Testing) • Integrate the Pieces and Test the System (System

Testing) • Deploy the System and Operate It

Waterfall model

Iterative lifecycle of the Web site Waterfall model

Waterfall model

• Shortcoming of this model:– Problems are not discovered until system testing. – Requirements must be fixed before the system is

designed - requirements evolution makes the development method unstable.

– Design and code work often turn up requirements inconsistencies, missing system components, and unexpected development needs.

– System performance cannot be tested until the system is almost coded; undercapacity may be difficult to correct.

Whirlpool model

Whirlpool model

Why? Questions Asked

Why? Questions Asked

Research

Problem Definition

“The Whirlpool”Critical Analysis

Purpose/ Goals

Eliminated Ideas

Concept Exploration & Feasibility Analysis

Whirlpool model

• Increased initial iteration

• Evolutionary prototyping and joint application development

• Developer and viewers collaborator

• Spiral model

Spiral out of control?

Evolutionary Models

• Spiral modelSpiral out of control?

• Lego block model

Flexiable, dismantable and reorganisable

Spiral model

Spiral Model • Plan: In this phase, the objectives, alternatives and constraints of the

project are determined and are documented. The objectives and other specifications are fixed in order to decide which strategies/approaches to follow during the project life cycle.

• Risk Analysis: This phase is the most important part of "Spiral Model". In this phase all possible (and available) alternatives, which can help in developing a cost effective project are analyzed and strategies are decided to use them. This phase has been added specially in order to identify and resolve all the possible risks in the project development. If risks indicate any kind of uncertainty in requirements, prototyping may be used to proceed with the available data and find out possible solution in order to deal with the potential changes in the requirements.

• Engineering: In this phase, the actual development of the project is carried out. The output of this phase is passed through all the phases iteratively in order to obtain improvements in the same.

• Customer Evaluation: In this phase, developed product is passed on to the customer in order to receive customer’s comments and suggestions which can help in identifying and resolving potential problems/errors in the software developed. This phase is very much similar to TESTING phase.

Web sites vs. Software

• Software is a computer program, or a set of computer programs plus associated materials like documentation.

• Range of complexity of Web sites– Static Web sites– Static with Form-Based

interactivity– Sites with Dynamic Data

Access– Dynamically Generated sites– Web-Based Software

Applications

Document centred Application centred

Complex

Simple

Pure static Web sites

Static Site withEntry Form

Dynamic Data Access via Web sites

Web Based Application

DynamicallyCreated sites

Diversity of Web sites’ Purpose

• Marketing needs

• Automated a business needs

• Access to information

• Entertainment

• Personal enjoyment

The Signs of a Well-Engineered Web sites

• Good Software:– Maintainable– Reliable– Efficient– Appropriate User Interface

• Good Web sites:– Correct

A site is correct if it performs properly and is functionally and cosmetically error free.– Testable– Maintainable– Portable and Scalable– Reusable– Robust and Reliable– Efficient– Readable– Well Documented– Appropriately Presented

Web Site Planning Process

• Problem Definition and Exploration– Understanding the Problem– Asking Why Questions

1. What is the Main Motivation for the Site:

2. Why is the Site Needed?

3. Who is the Site for?

4. Ask the End User

Problem Definition and Exploration

• You may also need to ask the following questions for you to design different Website– What you want?

• Sell something? • Promote something?

– Define your audience• Whom you sell to?• Who will be interested?

Writing the Problem Definition:Example

Big Company, Inc.Web Site Problem Exploration

Summary: This document summarizes some of the current problems facing the company. It is believed that ta Web site may be instrumental in solving some of these problems.

– Currently the firm spends a great deal of money sending out data books and product guides via mail. The current cost for printing and shipping one data book is approximately £20 per request.

– People are constantly requesting the list of distributors. A great deal of time is being spent distributing the list and keeping it sp to date manually.

– The firm needs to increase sales, particularly overseas where sales are flat.– The image of the firm is outdated and does not reflect the world-class stature of the

company. The current Web site does noting to dispel the belief.– Investors and other parties have expressed an interest in obtaining more timely financial

information.– Currently there is very little press coverage for the company.

Conclusion: It is believed that a Web site may be able to address some of these needs. For example, a Web site may be able to reach foreign customers better that traditional means and the cost saving by providing most product data sheets online may be significant when compared to current paper-based methods.

Web Site Planning Process

• Concept Exploration and feasibility- the whirlpool approach.

• Answering the problem definition: the Overall Purpose: Hard and Soft Measurements.

• Establishing a Measurement of Success.

Website Planning – Technical Issues

• Compile a wish list– graphics? – forms?– animation?– audio? – chat room?– forum?– database?

Website Planning – Technical Issues

Compile a tool list– graphics - Photo Shop, Photo Draw, etc.– forms - CGI scripts– animation - Image Ready, Fire Works, Flash

MX, etc– audio - software for MP3, AAC, AIFF, etc– chat room - CGI scripts, asp, Java, etc– forum - CGI scripts, asp, Java, etc– database - Access, SQL, etc

Website Planning – Technical Issues

• Weighing up the benifit/cost ratio• Domain names

– World of Internet - 5th dimensional?– Top domains

.com, .org, .edu, .uk, .us, info., .biz, .net

– Sub domains– Importance and value– http://www.greatdomains.com

• Domain registration• Wholesale: joker.com, networksolutions.com, etc.• Retail: uk2.net, etc.