why Human-computer Interaction?
Human-computer interaction is a multidisciplinary area of research that focuses on computer technology design and, in particular, user interaction with computers. Nowadays, the word “computer technology” encompasses much of the technology, from the obvious screen and keyboard computers to cell phones, household appliances, in-car navigation systems, and even embedded sensors and actuators such as automatic lighting. HCI has an associated design discipline focusing on how to design computer technology such that it is as simple and fun to use as possible, also called Interface Design or User-Centered Design.
DESIGN RULES FOR INTERACTIVE SYSTEMS
Interactive system designs are created to every one of the parts of plan and improvement of intuitive frameworks which are a part of real life. it simply specifies the mechanism behind accessing and changing the task information. In a user-centered design process, one of the key problems that must be solved is How to offer designers the ability to determine the effect on the usability of Their decisions on their model. So, design rules are a set of instructions that help the designer to improve the usability of the product.
General principles which can be applied to increase the usability of a product are known as abstract design rules. these usability design tools are divided into three main categories.
- Learnability: the ability where the new users can begin an effective interaction and get the maximum performance.
- Flexibility: the probability of cancer where the user and the system can exchange information
- Robustness: the support level given to the user to successfully achieve the goals.
Principles of learnability
- Predictability: support the user to predict future results based on the past.
- Synthesizability: support the user to access the past history.
- Familiarity: ability to use past experience in a new system.
- Generalizability: allow the user to access the knowledge internal and external situation
- Consistency: Likeness in input-output behavior coming from similar situations.
Principles of Flexibility
- Dialog Initiative: Allowing the user freedom from artificial constraints placed on the input dialog By the scheme.
- multi-threading: helps users to interact with more than one task.
- Task migratability: pass control for the execution of a given task so that it becomes either internalized by the user or the system or both.
- Substitutivity: Allowing equivalent values of input and output to be arbitrarily substituted for each other.
- Customizability: Modifiability of the user interface by the user or the system.
Principles of robustness
- Observability: Ability of the user to evaluate the internal state of the system from its perceivable representation.
- Recoverability: Ability of the user to take corrective action once an error has been recognized.
- Responsiveness: How the user perceives the rate of communication with the system.
- Task conformance: ableness of system to perform all the user needed tasks
Standards and guideline for interactive systems
Standards for interactive system design are usually set by national or international bodies to ensure compliance with a set of design rules by a large community. It is difficult to generate authoritative and precise standards because of the incompleteness of theories underlying the design of interactive applications. As a consequence, suggestive and more general guidelines are the majority of design rules for interactive systems.
Shneiderman’s 8 Golden Rules
- Strive for consistency
- Enable frequent users to use shortcuts
- Offer informative feedback
- Design dialogs to yield closure
- Offer error prevention and simple error handling
- Permit easy reversal of actions
- Support internal locus of control
- Reduce short-term memory load
Norman’s 7 Principles
- Use both knowledge in the world and knowledge in the head.
- Simplify the structure of tasks.
- Make things visible.
- Get the mappings right.
- Exploit the power of constraint.
- Design for error.
- When all else fails, standardize.
EVALUATION TECHNIQUES FOR INTERACTIVE SYSTEMS
Evaluation is a process where we access and test our design to check whether they are fulfilling the user requirements. Evaluation should take place during the life cycle of the design, with the evaluation results Feeding back into concept modifications. Usually, it is not possible to Continually conduct extensive experimental testing in the design, but You can and should use analytical and informal techniques. There is, in this respect, a Near connection between assessment and the concepts and techniques for prototyping that we have Such approaches help to ensure that the concept is continuously tested.
Goals of Evaluation
Evaluation contains three main goals.
- to assess the extent and accessibility of the system’s functionality.
does the system meet the user’s requirements?
is the system clear to operate?
does the system help make the user effective at her task? - to assess users’ experience of the interaction:
is the interface usable? is the user satisfied?
is the user’s experience using the interface pleasant?
is the user happy/angry/frustrated when using the interface?
take into account the user’s task, for example, if the interface is for a game, then the user should have fun using the system (playing the game). - to identify any specific problems with the system:
does the system produce errors?
is the user confused when using the system?
Evaluation through expert analysis
a number of methods have been proposed to evaluate interactive systems through expert analysis. These depend upon the designer, or a human factors expert, taking the design and assessing the impact that it will have upon a typical user. this helps the process to get finished in quick time and saves the additional and expensive works. The fundamental intention is to identify any areas that are likely to cause problems because they are in breach of recognized Cognitive beliefs, or ignore agreed scientific findings. there are 4 considerable approaches to expert analysis.
- cognitive walkthrough
Cognitive walkthrough is a form of usability testing in which one or more evaluators work through a series of tasks and ask from the user’s perspective a set of questions. The cognitive walkthrough’s emphasis is on recognizing the learning capacity of the system for new or infrequent users. to do a walkthrough we need
- A specification or prototype of the system
- A description of the task the user is to perform on the system.
- A complete, written list of the actions needed to complete the task with the proposed system.
- An indication of who the users are and what kind of experience and knowledge the evaluators can assume about them. - Heuristic evaluation
Heuristic evaluation is a process where experts use rules of thumb to measure the usability of user interfaces in independent walkthroughs and report issues. when a problem occurs in this method it will be categorized under one of these
0 = I don’t agree that this is a usability problem at all.
1 = Cosmetic problem only: need not be fixed unless extra time is available on the project.
2 = Minor usability problem: fixing this should be given low priority.
3 = Major usability problem: important to fix, so should be given high priority.
4 = Usability catastrophe: imperative to fix this before product can be released.
…..
Nielsen’s ten heuristics are:
1. Visibility of system status
2. Match between system and the real world
3. User control and freedom
4. Consistency and standards
5. Error prevention
6. Recognition rather than recall
7. Flexibility and efficiency of use
8. Aesthetic and minimalist design
9. Help users recognize, diagnose and recover from errors
10. Help and documentation
3. Model-based evaluation
The model-based evaluation uses a model of how a user will use a suggested method by estimation or simulation to achieve expected usability measures. These predictions may substitute the empirical measurements obtained by user testing or complement them. Design methodologies, such as design rationale also have a role to play in evaluation at the design stage. Design rationale provides a framework in which design options can be evaluated. By examining the criteria that are associated with each option in the design, and the evidence that is provided to support these criteria, informed judgments can be made in the design.
4. Using previous studies in evaluation
A final approach to expert evaluation exploits this inheritance, using previous results as evidence to support aspects of the design. It is expensive to repeat experiments continually and an expert review of relevant literature can avoid the need to do so. It should be noted that experimental results cannot be expected to hold arbitrarily across contexts.
Evaluation through user participation
The above techniques are so far depending on a design or system through analysis but user participation evaluation involves actual user. In the later stages of growth, user involvement in assessment appears to occur. When the device has at least a working prototype in place. Before we consider some of the techniques that are available for evaluation with users, we will distinguish between two distinct evaluation styles.
- Laboratory studies
- Advantages
- specialist equipment available
- uninterrupted environment - Disadvantages
- lack of context
- difficult to observe several users cooperating - Appropriate
- if system location is dangerous or impractical for constrained single user systems to allow controlled manipulation of use
2. Field studies
- Advantages
- natural environment
- context retained (can be altered through observation )
- longitudinal studies possible - Disadvantages
- distractions
- noise - Appropriate
- where context is crucial for longitudinal studies
now let’s discuss some techniques of evaluation through user participation
Experimental evaluation
- controlled evaluation of specific aspects of interactive behaviour.
- evaluator chooses hypothesis to be tested
- a number of experimental conditions are considered which differ only in the value of some controlled variable.
- changes in behavioral measure are attributed to different conditions
Experimental factors
- Subjects
- who
- representative, sufficient sample - Variables
- things to modify and measure - Hypothesis
- what you’d like to show - Experimental design
- how you are going to do it
Observational techniques
A popular way to gather information about actual use of a system is to observe users interacting with it. In this section, we consider some of the techniques used to evaluate systems by observing user behavior.
- Think Aloud
user observed performing the task. user asked to describe what he is doing and why what he thinks is happening etc.
- Advantages: simplicity, requires little expertise, can provide useful insight, can show how system is actually use
- Disadvantages: subjective, selective, act of describing may alter task performance
2. Cooperative evaluation
variation on think aloud. user collaborates in evaluation. both user and evaluator can ask each other questions throughout
- Additional advantages
- less constrained and easier to use
- user is encouraged to criticize system
- clarification possible
3. Protocol analysis
• paper and pencil: cheap, limited to writing speed
• audio: good for think aloud, difficult to match with other protocols
• video: accurate and realistic, needs special equipment, obtrusive
• computer logging: automatic and unobtrusive, large amounts of data difficult to analyze
• user notebooks: coarse and subjective, useful insights, good for longitudinal studies
• Mixed use in practice.
• audio/video transcription difficult and requires skill.
• Some automatic support tools available
4. automated analysis — EVA
• Workplace project
• Post task walkthrough: user reacts on action after the event, used to fill in intention
• Advantages: analyst has time to focus on relevant incidents, avoid excessive interruption of task
• Disadvantages: lack of freshness, may be post-hoc interpretation of events
5. post-task walkthroughs
•transcript played back to participant for comment
- immediately -> fresh in mind
- delayed -> evaluator has time to identify questions
• useful to identify reasons for actions and alternatives considered
• necessary in cases where think-aloud is not possible
Query Techniques
- Interviews
• analyst questions user on one-to-one basis usually based on prepared questions
• informal, subjective and relatively cheap
• Advantages: can be varied to suit context, issues can be explored more fully, can elicit user views and identify unanticipated problems
• Disadvantages: very subjective, time consuming - Questionnaires
• Set of fixed questions given to users
• Styles of question:
i) general
ii) open-ended
iii) scalar
iv) multi-choice
v) ranked
• Advantages: quick and reaches large user group, can be analyzed more rigorously
• Disadvantages: less flexible, less probing
Evaluation through monitoring physiological responses
other user participating techniques are most reliable on users but what if the user is not clear about his experience with the product? In this technique, designer can monitor a user directly and take the output experience himself. there are mainly two methods are being used in this technique.
- eye tracking
• head or desk mounted equipment tracks the position of the eye
• eye movement reflects the amount of cognitive processing a display requires
• measurements include
- fixations: eye maintains stable position. Number and duration indicate level of difficulty with display
- saccades: rapid eye movement from one point of interest to another
- scan paths: moving straight to a target with a short fixation at the target is optimal - physiological measurements
• emotional response linked to physical changes
• these may help determine a user’s reaction to an interface
• measurements include:
- heart activity, including blood pressure, volume and pulse.
- activity of sweat glands: Galvanic Skin Response (GSR)
- electrical activity in muscle: electromyogram (EMG)
- electrical activity in brain: electroencephalogram (EEG)
• some difficulty in interpreting these physiological responses — more research needed
UNIVERSAL DESIGNS FOR INTERACTIVE SYSTEMS
Universal Design Principals
- Equitable use
- Flexibility in use
- Simple and intuitive
- Perceptible information
- Tolerance for error
- Low physical effort
- Size and space for approach and use
You can look up this page for more detailed information about these principles.
Multimodel Interaction
Multimodal Interaction is a situation where the user is provided with multiple modes for interacting with the system. Multi-modal systems as those that process two or more combined user input modes such as speech, touch, visual and learning in a coordinated manner with multimedia system output. following are some of the alternative modes of human-computer communication, concentrating particularly on sound, touch, handwriting and gesture.
- Sound in the interface
Sound is an important contributor to usability. There is experimental evidence to suggest that the addition of audio confirmation of modes, in the form of changes in keyclicks, reduces errors. Speech is used to select and qualify one or multiple objects and their function to be manipulated. If an object offers only one function that can be manipulated, the selection process can be as short as just saying the name of this object and implicitly choosing its function.
2. Touch in the interface
Using a simple touch gesture, the interaction style lowers the visual demand and provides at the same time immediate feedback and easy means for undoing actions. After the selection of the interaction object and function, the user can perform a gesture to complete the intended action. This form of interaction allows for fine-grained manipulation and provides simple means for undoing an action. As the action is executed at the same time, immediate feedback is given by means of manipulating the objects.
3. handwriting recognition
Handwriting recognition, also known as Handwritten Text Recognition (HTR), is the ability of a computer to receive and interpret intelligible handwritten input from sources such as paper documents, photographs, touch-screens and other devices. Like speech, we consider handwriting to be a very natural form of communication. The idea of being able to interpret handwritten input is very appealing, and handwriting appears to offer both textual and graphical input using the same tools. There are problems associated with the use of handwriting as an input medium, however, and in this section we shall consider these.
4. Gesture recognition
Gesture recognition is a type of perceptual computing user interface that allows computers to capture and interpret human gestures as commands. The general definition of gesture recognition is the ability of a computer to understand gestures and execute commands based on those gestures.
Designing Interfaces for diversity
When we are designing a product we mostly consider certain type of users not everyone. unfortuanely this excludes other people who are going to use this product. for an example whe a game is being created mostly youngsters are considered as users but not only youngsters butalso some old people also like to play games.in these type of cases we need to consider three areas and those are:
- Designing for users with disabilities
It is estimated that at least 10% of the population of every country has a disability that will affect interaction with computers. As important as HCI is for designing programs used by the general public, it is even more important if the target audience is disabled. so when we concern about people with disability we need to consider visual impariment, hearing impariment, physical impariment, speech impariment, autism and duslexia. - Designing for different age groups
We have considered how people differ along a range of sensory, physical and cognitive abilities. Designing for different age groups is important for two reasons. First, ignoring an entire user base such as the elderly alienates them from the experience. And let’s face it: all of us will get old, and we wouldn’t want to be treated like that. Secondly, younger users will be tomorrow’s designers and tomorrow’s customers too. If they stumble upon our product and have an awful experience, that will likely stick with them and could shape their perception of the product or service.
refer this for more information:
https://www.webfx.com/blog/web-design/designing-for-different-age-groups/ - Designing for cultural differences
Over 3 billion people have access to the internet. This positive trend in global connectivity means that it’s becoming increasingly common for companies to design global web experiences. To do so effectively though, designers need to go beyond designing for seamless use and accessibility they need to create a cross-cultural user experience.
