User interface

In the industrial design field of human-machine interaction, the user interface is (a place) where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the machine which aids the operator in making operational decisions. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls. and process controls. The design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology.

A user interface is the system by which people (users) interact with a machine. The user interface includes hardware (physical) and software (logical) components. User interfaces exist for various systems, and provide a means of:

Generally, the goal of human-machine interaction engineering is to produce a user interface which makes it easy, efficient, enjoyable to operate a machine in the way which produces the desired result. This generally means that the operator needs to provide minimal input to achieve the desired output, and also that the machine minimizes undesired outputs to the human.

Ever since the increased use of personal computers and the relative decline in societal awareness of heavy machinery, the term user interface has taken on overtones of the (graphical) user interface, while industrial control panel and machinery control design discussions more commonly refer to human-machine interfaces.

Other terms for user interface include human-computer interface (HCI) and man-machine interface (MMI).

Contents

Introduction

Main article: Human-computer interaction

To work with a system, users have to be able to control and assess the state of the system. For example, when driving an automobile, the driver uses the steering wheel to control the direction of the vehicle, and the accelerator pedal, brake pedal and gearstick to control the speed of the vehicle. The driver perceives the position of the vehicle by looking through the windshield and exact speed of the vehicle by reading the speedometer. The user interface of the automobile is on the whole composed of the instruments the driver can use to accomplish the tasks of driving and maintaining the automobile.

Terminology

There is a distinct difference between User Interface versus Operator Interface or Human Machine Interface (HMI).

In science fiction, HMI is sometimes used to refer to what is better described as direct neural interface. However, this latter usage is seeing increasing application in the real-life use of (medical) prostheses—the artificial extension that replaces a missing body part (e.g., cochlear implants).

In some circumstance computers might observe the user, and react according to their actions without specific commands. A means of tracking parts of the body is required, and sensors noting the position of the head, direction of gaze and so on have been used experimentally. This is particularly relevant to immersive interfaces.

Usability

User interfaces are considered by some authors to be a prime ingredient of Computer user satisfaction. 

The design of a user interface affects the amount of effort the user must expend to provide input for the system and to interpret the output of the system, and how much effort it takes to learn how to do this. Usability is the degree to which the design of a particular user interface takes into account the human psychology and physiology of the users, and makes the process of using the system effective, efficient and satisfying.

Usability is mainly a characteristic of the user interface, but is also associated with the functionalities of the product and the process to design it. It describes how well a product can be used for its intended purpose by its target users with efficiency, effectiveness, and satisfaction, also taking into account the requirements from its context of use.

See also: mental model, human action cycle, usability testing, and ergonomics.
List of human-computer interaction topics

Consistency

A key property of a good user interface is consistency. There are three important aspects.[1]

First, the controls for different features should be presented in a consistent manner so that users can find the controls easily. For example, users find it very difficult to use software when some commands are available through menus, some through icons, and some through right-clicks. A good user interface might provide shortcuts or "synonyms" that provide parallel access to a feature, but users do not have to search multiple sources to find what they're looking for.

Second, the "principle of least astonishment" is crucial. Various features should work in similar ways. For example, some features in Adobe Acrobat are "select tool, then select text to which apply." Others are "select text, then apply action to selection."

Third, user interfaces should not change version-to-version—user interfaces must remain upward compatible.

Good user interface design is about setting and meeting user expectations. Better (from a programmer's point of view) is not better. The same (from a user's point of view) is better.

User interfaces in computing

In computer science and human-computer interaction, the user interface (of a computer program) refers to the graphical, textual and auditory information the program presents to the user, and the control sequences (such as keystrokes with the computer keyboard, movements of the computer mouse, and selections with the touchscreen) the user employs to control the program.

Types

Currently (as of 2009) the following types of user interface are the most common:

User interfaces that are common in various fields outside desktop computing:

Other types of user interfaces:

See also:

History

The history of user interfaces can be divided into the following phases according to the dominant type of user interface:

Modalities and modes

A modality is a path of communication employed by the user interface to carry input and output. Examples of modalities:

The user interface may employ several redundant input modalities and output modalities, allowing the user to choose which ones to use for interaction.

A mode is a distinct method of operation within a computer program, in which the same input can produce different perceived results depending of the state of the computer program. Heavy use of modes often reduces the usability of a user interface, as the user must expend effort to remember current mode states, and switch between mode states as necessary.

See also

References

  1. ↑ David E. Boundy, A taxonomy of programmers, ACM SIGSOFT Software Engineering Notes 16(4) 23-30 (October 1991)
  2. ↑ Appleinsider.com

External links