Human-Computer Interaction. (Interactive Systems)

First, see what Interactive Systems are? Interactive systems are computer systems characterized by significant amounts of interaction between humans and the computer. Most users have grown up using Macintosh or Windows computer operating systems, which are prime examples of graphical interactive systems. Editors, CAD-CAM (Computer-Aided Design-Computer Aided Manufacture) systems, and data entry systems are all computer systems involving a high degree of human-computer interaction. Games and simulations are interactive systems. Web browsers and Integrated Development Environments (IDEs) are also examples of very complex interactive systems.

Design rules for interactive systems

Design rules

● Can be supported by psychological, cognitive, ergonomic, sociological, economic, or computational theory.

● Designers do not always have the relevant background in the above

● Design rules are used to apply the theory in practice.

Principles are abstract design rules, with high generality and low authority. Principles can provide the repeatability which paradigms in themselves cannot provide.

1. Principles of Learnability

Allow novice users to understand how to use it initially and then attain a maximal level of performance. Several principles support learnability, which focuses on the features in the software system that allows users to understand how it works or how to have a maximum level of performance there are,

Predictability, Synthesizability, Familiarity, Generalizability, and Consistency

2. Principles of Flexibility

Flexibility is important for health and wellness. The principles of flexibility progressive overload, specificity, reversibility, individual differences, and balance need to be taken into consideration. Static stretching can help alleviate soreness and greatly improve flexibility. There are several principles that contribute flexibility which refers to the multiplicity of ways in which the end-user and the system exchange information. They are,

Dialog initiative, Multithreading, Task migratability, Substituvity, and Customizability

3. Principles of Robustness 

There is some principles support robustness which that interaction covers features that support the successful achievement and assessment of the goals. there are,

Observability — Observability should provide users with the ability to evaluate the internal state from its representation.

Recoverability — Recoverability is the ability to reach the desired goal after recognition of some error in a previous interaction.

Responsiveness— Responsiveness measures the rate of communication between the system and the user.

Task Conformance — Degree to which system services support all of the user’s tasks.

4. Standards and Guideline for Interactive systems 

Standards

There’s a lot more than that of using standards and guidelines for human-computer interaction (HCI) design. Such guides are a mixed blessing and could even be a mixed curse. Here are a few things it might help you to know.

Why do we want to use HCI standards in the first place?

To standardize the look and feel of a user interface. We certainly want to standardize the various windows and dialog boxes of a single product, and we may also want to standardize the interfaces of multiple products or systems that people may be using. In addition, we may want to standardize to some extent across all products for a single platform such as Macintosh, Windows, or Motif. Standardization facilitates learning and reduces errors by taking advantage of knowing the users have gained from other products or from other parts of your product

• International: standards developed by organizations to reflect agreements among national member organizations, for example,
• International Organization for Standardization (ISO) [http://www.iso.ch/], in particular, ISO 9241, Ergonomic Requirements for Office Work with Visual Display Terminals [http://www.iso.ch/cate/cat.html—search on ISO number 9241]

Guideline

There are many guidelines for user interface design. Guidelines can be automated to some extent, providing a direct means for translating detailed design specifications into actual implementation. Abstract guidelines applicable during early life cycle activities and detailed guidelines applicable during later life cycle activities

5. Shneiderman's 8 Golden Rules 

These rules were obtained from the text Designing the User Interface by Ben Shneiderman. Shneiderman proposed this collection of principles that are derived heuristically from experience and applicable in most interactive systems after being properly refined, extended, and interpreted

1. Strive for consistency in action sequences, layout, terminology, command use, and so on.
2. Enable frequent users to use shortcuts, such as abbreviations, special key sequences, and macros, to perform regular, familiar actions more quickly.
3. Offer informative feedback for every user action, at a level appropriate to the magnitude of the action.
4. Design dialogs to yield closure so that the user knows when they have completed a task.
5. Offer error prevention and simple error handling so that, ideally, users are prevented from making mistakes and, if they do, they are offered clear and informative instructions to enable them to recover.
6. Permit easy reversal of actions in order to relieve anxiety and encourage exploration, since the user knows that he can always return to the previous state.
7. Support internal locus of control so that the user is in control of the system, which responded to his actions.
8. Reduce short-term memory load by keeping displays simple, consolidating multiple-page displays, and providing time for learning action sequences.

6. Norman’s 7 Principles

To assess the interaction between humans and computers, Donald Norman in 1988 proposed seven principles. He proposed the seven stages that can be used to transform difficult tasks. Following are the seven principles of Norman −To assess the interaction between human and computers, Donald Norman in 1988 proposed seven principles. He proposed the seven stages that can be used to transform difficult tasks. Following are the seven principles of Norman −

1. Use both pieces of knowledge in the world and knowledge in the head.
2. Simplify the structure of tasks.
3. Make things visible: bridge the gulfs of Execution and Evaluation.
4. Get the mappings right.
5. Exploit the power of constraints, both natural and artificial.
6. Design for error.
7. When all else fails, standardize.

Evaluation techniques for interactive systems

What is the evaluation?

A process that assesses the design and tests the systems to ensure they perform as the requirement.

Goals of evaluation

• Assess the extent and accessibility of the system’s functionality
• Assess user’s experience of the interaction
• Identify any specific problems with the system

Evaluation through expert analysis

By having evaluation throughout the design process expensive mistakes can be avoided because the error can be discovered in an earlier stage. There are methods that have been proposed to evaluate interactive systems through expert analysis. These methods can be used at any stage in the development process from a design specification, through storyboards and prototypes, to full implementations, making them flexible evaluation approaches. And another advantage is the evaluation cost is relatively cheap.

o Cognitive walkthrough — Usability evaluation method in which one or more evaluators work through a series of tasks and ask a set of questions from the perspective of the user o do a walkthrough there are four things need to know.

• A specification or prototype of the system
• A description of the task the user is to perform
• A complete, written list of the actions needed to complete
• An indication of who the users are

o Heuristic evaluation — This is a method for structuring the critique of a system using a set of relatively simple and general heuristics. Heuristic evaluation can be performed on a design specification so it is useful for evaluating early design. Because of the flexible and relatively cheap approach, it is called a discount usability technique. To aid the evaluators in discovering usability problems, a set of 10 heuristics are provided.

Nielsen’s ten heuristics

• Visibility of system status
• Match between system and the real world
• User control and freedom
• Consistency and standards
• Error prevention
• Recognition rather than recall
• Flexibility and efficiency of use
• Aesthetic and minimalist design
• Help users recognize, diagnose and recover from errors
• Help and documentation

o Model-based evaluation — Model-based evaluation is combining cognitive and design models to the evaluation process.

Examples,

• GOMS model
• Keystroke-level model
• Design rationale
• Dialog models

Evaluation through user participation:

User participation in evaluation tends to occur in the later stages of development. This may range from a simulation of the system’s interactive capabilities, without its underlying functionality.

Styles of evaluation

will distinguish between two distinct evaluation styles, those performed under laboratory conditions and those conducted in the work environment or ‘in the field’.

Universal Design Principles

In the late 1990s, a group at North Carolina State University in the USA proposed seven general principles of universal design which give us a framework in which to develop universal designs.

· Equitable use — the design is useful to people with a range of abilities and appealing to all and no user is excluded or stigmatized

· Flexibility in use — the design allows for a range of ability and preference, through the choice of methods of use and adaptivity to the user’s pace, precision, and custom.

· simple and intuitive to use — regardless of the knowledge, experience, language, or level of concentration of the user. The design needs to support the user’s expectations and accommodate different language and literacy skills

· perceptible information — the design should provide effective communication of information regardless of the environmental conditions or the user’s abilities. The redundancy of presentation is important: information should be represented in different forms or modes.

· tolerance for error — minimizing the impact and damage caused by mistakes or unintended behavior. Potentially dangerous situations should be removed or made hard to reach and potential hazards should be shielded by warnings

· low physical effort — systems should be designed to be comfortable to use, minimizing physical effort and fatigue. The physical design of the system should allow the user to maintain a natural posture with reasonable operating effort.

· size and space for approach and use — Can be reached and used by any user regardless of body size, posture, or mobility. All physical components should be comfortably reachable by seated or standing users

Multi-Modal Interaction

• Providing access to information through more than one mode of interaction
• A situation where the user is provided with multiple modes for interacting with the system
• There are five senses → sight, sound, touch, taste, and smell
• A Multi-modal interface acts as a facilitator via these modes of interaction

Sound in the interface

• An important multi-modal interaction to usability
• More widespread effective use of sound in the interface would alleviate the problems faced by visually impaired people
• There are two types of sound that we could use → Speech, Non-speech

Touch in the interface

Touch aids users in understanding where they can physically interact with the screen simply and naturally. Touch interactions require three things.

• A touch-sensitive display.
• The direct contact of one or more fingers on that display.
• Movement of the touch.

Handwriting recognition

Handwriting recognition is the ability of a computer to receive and interpret intelligible handwritten input from sources.

Handwriting is a common and familiar activity and is therefore attractive as a method of text entry.

If we were able to write as we would when we use paper, but with the computer taking this form of input and converting it to text, we can see that it is an intuitive and simple way of interacting with the computer.

Gesture recognition

The gesture is a component of human-computer interaction that has become the subject of attention in multimodal systems.

Designing Interfaces for diversity, considering three key areas: disability, age, and culture.

In a society, there are many disabled people who suffered while doing their day-to-day activities. Designers should pay attention to how will affect it when disabled people interact with computers. Luckily nowadays we can see many new technologies which can be very helpful for those people to interact with digital equipment. Here are some examples of solutions for different impairments.

• visual impairment — screen readers, SonicFinder
• hearing impairment — text communication, gesture, captions
• physical impairment — speech I/O, eye gaze, gesture, predictive systems (e.g. Reactive keyboard)
• speech impairment — speech synthesis, text communication
• dyslexia — speech input, output
• autism — communication, education

Older and younger people have different intentions and abilities when it comes to technology. Older people need more simple designs or communication tools to prevent social isolation.

There are some key factors when we consider cultural diversity. These include language, cultural symbols, gestures, and the use of color in the design.

Universal design is about designing systems that are accessible by all users in all circumstances, taking account of human diversity in disabilities, age, and culture.