Systems Analysis and Design chapter 4

Systems Analysis and Design 11th Edition

• User Interface Design chapter objectives include explaining user interface design and human-computer interaction, as well as user-centered design principles.
• Interface designers perform tasks to describe rules for successful interface design and discuss input and output technology issues.
• Design effective source documents and forms, explain printed output guidelines, describe output and input controls and security, and explain modular design and prototyping techniques.
• Systems design aims to create effective, reliable, and maintainable systems.
• Effective systems support business needs and user needs.
• Reliable systems handle different types of errors, including input errors, processing errors, hardware failures, and human mistakes.
• Maintainable systems are flexible, scalable, and easy to modify.
• To design a successful system, think like a user, anticipate future needs and provide flexibility, offer several alternatives, manage data effectively, have input data close to the source, and include audit trails.
• Users have more control over their output, centralized IT departments don't produce large amounts of printed reports, and the user interface continues to evolve to meet the needs of mobile and wearable devices.
• A user interface describes how users interact with a computer system.

What Is a User Interface?

• Describes how users interact with a computer system.
• Comprises features affecting two-way communications between the user and the computer.
• Central to usability, distinguishing between input, output, and the interface.

Human-Computer Interaction (HCI)

• Describes the relationship between computers and people who use them.
• Early interfaces included complex commands and graphical user interfaces (GUIs).
• Transparent user interfaces do not distract the user.
• The objective is a user-friendly design that's easy to learn.

Seven Habits of Successful Interface Designers

• Understand the Business: Includes the underlying business functions, how the system supports individual, departmental and enterprise goals.
• Maximize Graphical Effectiveness: A well-designed interface allows for rapid learning.
• Think Like a User: The designer should see the system from the user's perspective.

Use Models and Prototypes

• Designers can present initial screen designs to users via storyboards.
• Users can test the design and provide feedback.
• Focus on usability by including main options on the opening screen and offering a reasonable number of choices that users easily understand.

Invite Feedback

• Monitor system usage and solicit user suggestions.
• Determine if system features meet intended use by observing and surveying users.
• Document all screen designs for programmers to refer to in the future.
• User-approved sketches and storyboards can be used to document the user interface.

Guidelines for User Interface Design

• Focus on system design objectives to create a design that's easy to understand and remember.
• Design consistent commands, actions, and system responses.
• Allow users to correct mistakes easily.
• Label controls, buttons, and icons clearly.
• Select images, on-screen instructions, and menu item listings that users can understand and are logical.
• Make it easy to navigate or return to different levels in the menu structure.

Enhance User Productivity

• Organize tasks, commands, and functions to mirror actual business operations.
• Create alphabetical menu lists and place frequently used selections at the top.
• Provide shortcuts for experienced users.
• Use default values if the majority of values in a field are the same; provide a duplicate value function, but allow users to disable it if needed.
• Provide a fast-find feature and consider using natural language processing for commands or requests.
• Include appropriate help and feedback.

Guidelines for User Interface Design

• Ensure that help is always available on demand.
• Provide user-selected help and context-sensitive help.
• Create a direct route for users to return to where they were previously in the application.
• Provide contact information.
• Require user confirmation before data deletion, and provide an Undo key when errors are made.
• Highlight erroneous parts of commands.
• Use hypertext links to assist users.
• Display messages logically on the screen.
• Alert users to lengthy processing times or delays.
• Allow messages to stay on the screen long enough for users to read them.
• Let the user know whether the task or operation was completed successfully.

Guidelines for User Interface Design

• Customer order tracking systems, including tasks, commands, and functions, should be organized into logical groups and sequences, similar to a functional decomposition diagram (FDD).
• Provide a clear flow, with information logically arranged from left to right and top to bottom. Ensure the order of printed fields is logical and that totals are clearly identified.

Printed Output

• In designing printed output, consider who needs the information and why, the specific information needed, whether the output is for a specific device and whether security and confidentiality issues exist.
• The overview of report design involves reducing printed reports and using screen output, emphasizing easy-to-read, well-organized reports, and using database programs with report design tools.
• Types of reports include detail reports (for each record), exception reports (only records meeting conditions), and summary reports (providing comprehensive data).
• All report designs should be approved by users; creating mock-ups or prototypes can ensure the appropriate user input.

Report Design Principles

• Reports should have header and footer elements containing title, date, and other relevant information.
• Page headers and footers should identify the data.
• Page footers should display the report title, page number, and data elements.
• Repeating fields help provide clarity.
• A report's consistent design and layout enhance the user experience.

Output Technology

• Output can be delivered via screens, printed matter, actual forms, or digitally on devices.
• Options for delivery include internet-based information, documents downloadable from websites, or live or prerecorded webcasts.
• Technologies, including email, web-based logs (blogs), instant messaging, wireless devices and digital audio/images/video can improve the user experience.

Output Technology

• Digital audio, video, and image formats can be stored in digital format, and can be incorporated as clips or attachments in documents.
• Podcasts can serve as a form of communication.
• Automated fax and faxback systems allow customers to send and receive faxes by various methods.
• Computer output to microfilm (COM) allows for archiving of documents, and computer output to digital media is helpful for users needing quick retrieval and scanning of paper documents.
• Specialized formats such as portable, internet-connected devices run multiple applications, retail point-of-sale terminals, and automatic teller machines can handle bank transactions.

Input Technology

• Input technology includes traditional methods (keyboard, mouse, pointing devices, microphones, OCR, and MICR).
• Evolving methods include body motion detection, advanced voice recognition, biological feedback, and RFID.
• Emerging methods include brain-computer interfaces (BCIs), neural networks, advanced motion sensors, two-way satellite interfaces, virtual environments, and 3-D technology.

Input Technology

• Batch input occurs on a schedule, and online data entry is done immediately, enabling verification and device-assisted automated input. Technologies like RFID tags, magnetic data strips, and smartphones facilitate fast and accurate data input.
• Source data automation examples include point-of-sale (POS) terminals with scanners, ATMs that read bank cards, factory employee ID cards, hospitals' barcodes on patient bracelets, and portable scanners and handheld scanners for retail and libraries.
• Manual data entry is slower and more expensive but occurs in real-time, often during high-demand periods, thus the choice depends on the business requirements.

Security and Control Issues

• Output control measures maintain output security and integrity.
• Security measures protect proprietary data from unauthorized access.
• Diskless workstations support a user interface but limit printing or copying, while port protectors control access.
• Input control measures ensure data correctness, completeness, and security, with source documents traced to input data.
• Procedures handle data integrity, ensuring data is not lost before entering the system.
• Data security policies and procedures protect against data loss or damage.

Modular Design

• Individual components, called modules, connect to a higher-level program or process.
• Modules perform specific functions and are used to build structured designs.
• These modules are reflected in data flow diagrams (DFDs) and are described in process descriptions.

Prototyping and Its Benefits

• Prototyping involves a repetitive sequence of analysis, design, modeling, and testing.
• System prototyping produces functional models for users to review and provide feedback.
• Design or throwaway prototyping is used to verify requirements and is discarded after the user feedback process.
• Prototyping avoids misunderstandings between users and systems developers.
• System developers can create accurate specifications using the prototype.
• Managers can better assess models compared to document-only methods.
• Prototyping supports user testing, training, and reduces financial risks associated with completed system failures.

Prototyping - Potential Problems

• Rapid pace of development can create problems not discovered until the operational phase.
• System requirements regarding reliability and maintainability cannot be adequately tested in prototypes.
• Complex systems can pose challenges regarding prototype management and handling.
• Client adoption of prototypes could potentially lead to increased future maintenance costs due to limited or no changes made.

Chapter Summary

• Database design aims to create a physical model that meets analysis phase specifications.
• User interfaces should reflect user perspectives.
• Reports should be detail, exception, or summary reports with logical zones, data capture and entry methods, and crucial security measures.

Data Design Concepts

• Data structures provide frameworks for organizing, storing, and managing data using files or tables.
• Each data file focuses on people, places, things, or events.
• File-oriented systems, like Mario's auto shop system, store data in separate files.
• Relational models, like Danica's, connect data through common fields within tables.
• File processing remains relevant in handling large volumes of structured data and remains cost-effective in specific situations.
• Database management systems (DBMS) are efficient, adaptable, and robust systems for data management, enabling flexible expansion and modification as needed.
• Database administrators (DBAs) are responsible for maintaining and securing databases given access levels appropriate for different users.
• Web-based data designs are global, and highly adaptable to different platforms, but require a different approach to security compared to traditional models.

Data Design Terms

• Entity: Refers to a person, place, thing, or event, for which data is stored and maintained.
• Table/file: Collection of related records for a specific entity.
• Field (attribute): Single data characteristic of an entity.
• Common field: Appears in multiple entities.
• Tuple /record: Describes an instance of an entity.
• Primary key: Uniquely identifies each entity.
• Candidate key: A field that can serve as the primary key if needed.
• Foreign key: Connects related records in different tables.
• Secondary key: Used to narrow down records for specific searches.
• Referential integrity: Ensures the consistency and quality of data relationships.
• Entity-relationship diagrams (ERDs): Graphic representations of database structure and relationships.
• Cardinality: Numeric relationship between entities.

Data Normalization

• Normalization is a data design process that improves data structure by assigning specific fields to tables.
• Normalization progresses through stages: unnormalized, first normal form (1NF), second normal form (2NF), and third normal form (3NF).
• In 1NF, tables eliminate repeating groups.
• Standard notation shows table structure, including underlined primary keys; repeating group recognition is important.
• 2NF means that all non-key fields depend on the entire primary key, and 3NF adds a condition stating that non-key fields must not depend on other non-key fields.

Using Codes

• Codes are short representations of data, reducing storage space and costs.
• Codes reduce data entry and transmission time, potentially reducing data input errors and enhancing memorability.
• Categories of codes include sequence, block sequence, significant digit and mnemonic codes, as well as derivation, cipher, and action codes.
• Various codes are useful to identify different elements depending on specific needs.

Data Storage and Access

• Data warehousing involves a centralized storage of data from various sources allowing users to view, understand, and access data that may not always be organized or stored in a manner that is visible or understood.
• Data warehousing is designed to meet specific departmental needs.
• Data mining analyzes data to discover meaningful patterns and relationships between data elements that include increasing page views, referrals, reduced customer checkouts per visit and an increase in overall profit per checkout.
• Logical data storage is how users perceive and interact with data irrespective of where it is physically stored.
• Physical data storage refers to how data is stored on physical media.
• Data coding formats, such as EBCDIC and ASCII and Unicode, are standardized ways to represent data in computer storage.
• Dates can be stored using an International Organization for Standardization (ISO) format, with year, month, and day represented by numerical values.
• Data control ensures data security and integrity using backup copies, recovery procedures, and audit trails.