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HCI (human-computer interaction) is the study of how people interact with computers and to what extent computers are or are not developed for successful interaction with human beings. A significant number of major corporations and academic institutions now study HCI.
As its name implies, HCI consists of three parts: the user, the computer itself. And the ways they work together.
By "user", we may mean an individual user, a group of users working together. An appreciation of the way people's sensory systems (sight, hearing, touch) relay information in vital Also, different users from different conceptions or mental models about their interactions and have different ways of learning and keeping knowledge and. In addition, cultural and national differences play a part.
When we talk about the computer, we're referring to any technology ranging from desktop computers, to large scale computer systems. For example, if we were discussing the design of a Website, then the Website itself would be referred to as "the computer". Devices such as mobile phone or VCRs can also be considered to be "computers".
There are obvious differences between humans and machines. In spite of these, HCI attempts to ensure that they both get on with each other and interact successfully. In order to achieve a usable system, user need to apply what user know about humans and computers, and consult with likely users thought the design process. In real systems, the schedule and the budget are important, and it is vital to find a balance between what would be ideal for the users and what is feasible in reality.
The Goals of HCI
The goals of HCI are to produce usable and safe systems, as well as functional systems. In order to produce computer systems with good usability, developers must attempt to:
Understand the factors that determine how people use technology
Develop tools and techniques to enable building suitable systems
Achieve efficient, effective, and safe interaction
Put people first
Underlying the whole theme of HCI is the belief that people using a computer system should come first. Their needs, capabilities and preferences of conducting various tasks should direct developers in the way that they design systems. People should not have to change the way that they use a system in order to fit in with it. Instead, the system should be designed to match their requirements.
Define Question 1
Defining the interaction framework
The Requirements Definition phase sets the stage for the core of the design effort: defining the interaction framework of the product. The interaction framework defines not only the skeleton of the interaction and its structure but also the flow and behavior of the product. The following six steps the process of defining the interaction framework is:
Defining from factor and input methods
Defining views defining view
Defining functional and data elements
Determining functional groups and hierarchy
Sketching the interaction framework
Constructing key path scenarios like previous processes, this is not linear effort, but requires iteration.
(Human-Computer Interaction, lower price edition,2002,by John M, Carroll)
The common interaction style is:
Command line interface
Form-files and spreadsheets
Point and click
Question/answer and query dialogue
(Human-Computer Interaction notes 2010 by Miss Liza, Chapter 3, The interaction)
Answer for Question 1 (a)
Figure 1.1 The Interaction framework in Human Computer Interaction
Framework and uses it to place different areas that related to HCI. See figure 1.1. the field of ergonomics addresses issues on the user side of the interface, covering input and output, as well as the user's immediate context. Dialog design and interface styles can be place particularly along the input branch of the framework, addressing both articulation and performance. However, dialog is most usually associated with the computer and so it biased to the side of the framework. Presentation and screen design relates to the output branch of the framework. The entire framework can be placed within a soial and organizational context that also affects the interaction. Each of these areas has important implications for the design the interactive systems and the performance of the user.
Ergonomics or human factors is traditionally the study of the physical characteristic of the interaction how the controls are designed, the physical environment in which the interaction takes place, and the layout and physical qualities of the screen. A primary focus is on user performance and how the interface enhances or detracts from this. In seeking to evaluate thee aspects of the interaction, ergonomics will certainly also touch upon human psychology and system constrains. It is a large and established field, which is closely related to but distinct from HCI. Physical aspects of interface are as follow:
Arrangement of controls and displays
The physical environment
Use of color
The bottleneck in improving the usefulness of interactive systems increasingly
lies not in performing the processing task itself but in communicating requests and
results between the system and its user. The best leverage for progress in this area
therefore now lies at the user interface, rather than the system internals. Faster, more
natural, and more convenient means for users and computers to exchange information
are needed. On the user's side, interactive system technology is constrained by the
nature of human communication organs and abilities; on the computer side, it is constrained only by input/output devices and methods that we can invent. The challenge
before us is to design new devices and types of dialogues that better fit and exploit the
communication-relevant characteristics of humans.
The problem of human-computer interaction can be viewed as two powerful
information processors (human and computer) attempting to communicate with each
other via a narrow-bandwidth, highly constrained interface. Research in this area attempts to increase the useful bandwidth across that interface. Faster, more natural and particularly less sequential, more parallel modes of user-computer Communication will help remove this bottleneck.
Current technology has been stronger in the computer-to-user direction (output devices in computer science terms, which we will use hereinafter, but input devices in psychological terms) than user-to-computer, so user-computer dialogues are typically one-sided, with the bandwidth from the computer to the user far greater than that from user to computer. We are especially interested in input media that can help redress this imbalance by obtaining data from the user conveniently and rapidly. Input is a neglected field relative to output, particularly considering the great strides made in computer graphics, but for that reason it is also an area that provides the greatest opportunity for research and progress. Interestingly, however, input is the source of perhaps the single biggest success story for theoretically-based research in HCI. A basic research program in interactive systems provides the opportunity to go beyond the immediate concerns of developing the user interface for each particular new system and allows the study of HCI problems that pervade many future systems, and thus such research can have far greater leverage in the long run. The relationship between basic research and application development in this area ideally forms a circular chain: specific interface problems encountered in applications are generalized and then solved in basic research by inventing new interaction modes or techniques; and these general approaches can then be applied to the development of specific user interfaces.
Finally, it is important to remember that modifying the user interface of a system, particularly the characteristics of its input/output media is not simply tinkering with the superficial appearance of the system. It changes the users' fundamental perception of a system. Interaction research goes to the heart of how people comprehend and work with computer systems, not simply the surface.
(Human-computer interaction, first edition,2004,by Alan Dix, Janet Finlay, Gregory D.Abowed)
Answer Question 1 (b)
Four different interaction styles used to accommodate the dialog between user and a computer is:
Command line interface
Provides a means of expressing instructions to the computer directly, using function keys, single characters, abbreviations or whole-word commands. In some systems it is the only way of communicating with the system, for example like remote access using telnet. More commonly it supplements menu-based interfaces, giving experienced users accelerated access to the system's functionality. Flexible and powerful but may be difficult to learn and use. Because commands must be remembered it is better for expert users than novice.
The set of available options is displayed on the screen, and selected using the mouse, or numeric or alphabetic keys. These visible options rely on recognition rather than recall, but still need to be meaningful and logically grouped. Menus may be nested hierarchically, with the grouping and naming of menu options the only cue for finding the required option. May be text based or have a graphical component.
Natural language Understanding
This is of speech and written input is the focus of much research. Natural language is very difficult for a machine to understand. It is ambiguous, syntactically and semantically. It is difficult to provide the machine with context. Unlikely that a general natural language interface will be available soon, but systems can be built to understand restricted subsets of a language. They are limited and the user has to learn what the computer understands.
Question/answer, query dialogue Question/answer
The dialogue is a simple mechanism for providing input to an application in a specific domain. The user is asked a series of questions (mainly with yes/no responses, multiple choice, or codes) and is led through the interaction step by step. Easy to learn and use, but limited in functionality and power. Appropriate for restricted domains and novice/casual users. Query languages are used to construct queries to retrieve information from a database. They use natural-language-style phrases, but require specific syntax and knowledge of the database structure. Their effective use requires some experience.
(Human-Computer Interaction notes 2010 by Miss Liza, Chapter 3, The interaction)
Define Question 2
Principle: "Golden Rules"
HCI( Human Computer Interaction ) gurus provide individual takes on the most important elements of good user interfaces. Here are Shneiderman's Eight Golden Rules:
Strive for consistency
Cater to universal usability
Offer informative feedback
Design dialogs to yield closure
Permit easy reversal of actions
Support internal locus of control
Reduce short-term memory load
Answer Question for Question 2
Shneiderman's Eight Golden Rules of Interface Design are user interface design rules described in designing the User Interface: Strategies for Effective Human Computer Interaction. 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.
To improve the usability of an application it is important to have a well designed interface and these "Eight Golden Rules of Interface Design" are claimed to be a guide to a good interaction design.
Strive for consistency - consistent sequences of actions should be required in similar situations. It identical terminology should be used in prompts, menus, and help screens and consistent commands should be employed throughout.
Enable frequent user to sue shortcut - As the frequency of use increases, so do the user's desires to reduce the number of interactions and to increase the pace of interaction. Abbreviations, function keys, hidden commands, and macro facilities are very helpful to an expert user.
Offer informative feedback - For every operator action, there should be some system feedback. For frequent and minor actions, the response can be modest, while for infrequent and major actions, the response should be more substantial.
Design dialog to yield closure - Sequences of actions should be organized into groups with a beginning, middle, and end. The informative feedback at the completion of a group of actions gives the operators the satisfaction of accomplishment, a sense of relief, the signal to drop contingency plans and options from their minds, and an indication that the way is clear to prepare for the next group of actions.
Offer simple error handling - As much as possible, design the system so the user cannot make a serious error. If an error is made, the system should be able to detect the error and offer simple, comprehensible mechanisms for handling the error.
Permit easy reversal of actions - This feature relieves anxiety, since the user knows that errors can be undone. If an error is made, the system should be able to detect the error and offer simple, comprehensible mechanisms for handling the error.
Support internal locus of control - Experienced operators strongly desire the sense that they are in charge of the system and that the system responds to their actions. Design the system to make users the initiators of actions rather that the responders.
Reduce short- term memory load - The limitation of human information processing in short term memory requires that displays be kept simple, multiple page displays be consolidated, window-motion frequency be reduced, and sufficient training time be allotted for codes, mnemonics, and sequences of actions.
( Reading in human-computer interaction, toward the year 2000, by Ronald M.Baecker Jonathan Grudin William A.S.Buxton Saul Greenberg )
Conclusion & Recommendation
The human-computer interface can be described as the point of communication between the human user and the computer. The flow of information between the human and computer is defined as the loop of interaction. The loop of interaction has several aspects to it including:
Task Environment: The conditions and goals set upon the user.
Machine Environment: The environment that the computer is connected to, i.e. a laptop in a college student's dorm room.
Areas of the Interface: Non-overlapping areas involve processes of the human and computer not pertaining to their interaction. Meanwhile, the overlapping areas only concern themselves with the processes pertaining to their interaction.
Input Flow: The flow of information that begins in the task environment, when the user has some task that requires using their computer.
Output: The flow of information that originates in the machine environment.
Feedback: Loops through the interface that evaluate, moderate, and confirm processes as they pass from the human through the interface to the computer and back.
Need to follow user interface principles? In the past, computer software was designed with little regard for the user, so the user had to somehow adapt to the system. This approach to system design is not at all appropriate today the system must adapt to the user. This is why design principles are so important.
Computer users should have successful experiences that allow them to build confidence in themselves and establish self-assurance about how they work with computers. Their interactions with computer software should be "success begets success." Each positive experience with a software program allows users to explore outside their area of familiarity and encourages them to expand their knowledge of the interface. Well-designed software interfaces, like good educators and instructional materials, should build a "teacher-student" relationship that guides users to learn and enjoy what they are doing. Good interfaces can even challenge users to explore beyond their normal boundaries and stretch their understanding of the user interface and the computer. When you see this happen, it is a beautiful experience.
Understanding and awareness of the user's mental model and the physical, physiological, and psychological abilities of users.