How to design conventional components - Graphical Design Notation and Tabular Design Notation

There were some logical constructs developed from which any program could be formed. Each construct has a logical structure. The constructs are sequence, condition, and repetition.
- Sequence implements processing the steps that are essential in the specification of any algorithm.
- Condition provides the facility for selected processing based on some logical occurrence.
- Repetition allows for looping.
Structured programming is a design technique that constrains logic flow to three constructs: sequence, condition and repetition. The structured constructs were supposed to limit the procedural design of software to a small number of predictable operations.

GRAPHICAL DESIGN NOTATION
Activity diagram allows a designer to represent sequence,condition and repetition. Flowchart, like an activity diagram, is quite simple pictorially.
The dogmatic use of only structured constructs can introduce inefficiency when an escape from a set of nested loops or nested conditions is required. Additional complication of all logical tests along the path of escape can hinder the control flow, increase the possibility of error and have a negative impact.
There are two options:
- procedural representation is redesigned so that escape branch is not required at a nested location.
- structured constructs are violated in a controlled manner; that is , a constrained branch out of the nested flow is redesigned.

TABULAR DESIGN NOTATION
Decision tables translates actions and conditions in a tabular form. It is difficult to misinterpret. A decision table is divided into quadrants:
- Upper left quadrant: contains a list of all conditions.
- Lower left quadrant: contains a list of all actions that are possible based on combinations of conditions.
- Right hand quadrant: a matrix that indicates condition combinations and corresponding actions. Each column of matrix may be interpreted as a processing rule.

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Aesthetic or Graphic Design - Layout Issues and Graphic Design Issues

Aesthetic or Graphic design makes the web application appealing, though it is functional in nature. It is an artistic angle that compliments the technical aspects of web engineering. To perform aesthetic design, web application users decide how they want the application to look like.

General Layout Guidelines To Consider When Screen Layout Is Designed

- Do not over crowd the web page with too much information as it makes it difficult for the suer to identify the needed information and it creates too much visual chaos.
- Scrolling on web page should be reduced as the users prefer not to scroll much. The best idea is to reduce the content or just put necessary content.
- The design should specify all layout items as a percentage of available space.
- There has to be a pattern that should be followed during group navigation, content and function geographically within the page.
- Web application should be designed in a way in which there is more emphasis on content. A typical web page should contain eighty percent of content with the remaining part dedicated to navigation and other features.
- Users have a tendency to scan the web page in a way they scan the page of a book i.e. from top-left to bottom right. High priority elements should be placed in upper-left portion of the page.

GRAPHIC DESIGN ISSUES

Graphic design begins with layout and then it covers the color schemes, sizes, styles, use of media, typefaces and all other aesthetic elements of an application.
Different web sites provide design tips and guidelines.