Unit 6 of COMP648 User Interface and Interaction Methods Dr Oscar Lin School of Computing and Information Systems Faculty of Science and Technology Athabasca University July 18, 2013

Goals Explore what constitutes user interface and interaction methods in HCI Discuss the different possible theories related to their design Go through several aspects of input techniques, including input devices and methods for their evaluation.

Content Input Techniques Multimodal interaction User interface toolkits

Input Techniques Better known Input devices – Pointing devices, mouse, joystick, touchpad, and touch screen – Text entry devices QWERTY keyboards, mobile keyboards, and handwritten text recognition

Properties of Input Devices Type of information that the device can sense and capture Number of dimensions that a device can handle simultaneously, Direct or indirect input sensing, and Device acquisition time

Evaluating the Effectiveness of an Input devices Fitts’s Law The Hick-Hyman Law The Steering Law The Keystroke Level Model

Fitts’s Law

The Hick-Hyman Law describes the time it takes for a person to make a decision as a result of the possible choices he or she has; that is, increasing the number of choices will increase the decision time logarithmically. where p i refers to the probability of the ith alternative yielding the information-theoretic entropy.

The Steering Law a predictive model of human movement that describes the time required to navigate, or steer, through a 2-dimensional tunnel. where T is the average time to navigate through the path, C is the path parameterized by s, W(s) is the width of the path at s, and a and b are experimentally fitted constants. In general, the path may have a complicated curvilinear shape (such as a spiral) with variable thickness W(s).

The Steering Law One potential practical application of this law is in modeling a user's performance in navigating a hierarchical cascading menu. Question: what is the relationship between the steering law and Fitts’s law ?

The Keystroke Level Model (KLM) The model is an 11-step method that can be used by individuals or companies seeking ways to estimate the time it takes to complete simple data input tasks using a computer and mouse. By using KLM, individuals often find more efficient or better ways to complete a task simply by analyzing the steps required in the process and rearranging or eliminating unneeded steps.

11-step method Step 1 — Obtain a working prototype of computer interface or a step by step operational description of a task. Step 2 — Identify the goals or the desired outcome of work. Step 3 — For each of these goals, find subgoals or tasks that achieve the main goals. Step 4 — Identify methods to main goals and all subgoals. Step 5 — Convert description of methods to pseudo-code (the terminology that is described above). Step 6 — State any and all assumptions used in the making of pseudo-code and goals. Step 7 — Determine appropriate mental or keystroke operators for each step. Step 8 — Assign time values to mental or keystroke operators. Step 9 — Add up execution times for operators.

Step 10 — Adjust total time of task to be sensitive by age of expected. Age Time Adjustment Multiplier (Multiply task time by this value) Use as is 30–40 ??? 40–55By –60By 1.7 > 65By 2.2 Step 11-Verify validity of results

Multimodal vs Multimedia Multimodal interaction refers to a case where an input interface accepts two or more modes of input. Multimedia interaction is related to cases where an output device provides output information in two or more modes of communication.

Multimodal Communication’s Possibility Using different human perception mechanisms while others are busy – e.g., the eyes are busy, but the ears can still hear and take input Mutual disambiguation – i.e., the information gathered by the eyes can be cross-validated with those from the ears Faster and higher quality interaction More natural for human beings.