HCI 3020 FInal Prep Pt 1

ohsobeezee23's version from 2016-12-20 19:50


Question Answer
Conscious CognitionOur focus of attention,
Serial Processorcan attend to only one thing at once
Unconscious CognitionParallel processing, Higher bandwidth, Long term memory and Lots of resources to draw upon
Sensory memoryhigh capacity
Short duration
Short-term memorylow-capacity
Fast access

Short duration
Long-term memoryslow access
Large capacity

Long duration

Design Principles pt1

Question Answer
Design PrinciplesGeneric "rules of thumb" that describe features of "usable" systems
used in heuristic evaluation and referred to then as usability principles
Visibility #1Make core user functions clearly apparent
Hide secondary user functions
Structure enhances visibility
Constraints #2Restrict the kinds of user actions that can take place for any given mode of interaction
Provide people with a range of usage possibilities
Feedback#3Continuously inform the user about what the system is doing
How the system is interpreting the user's input

User should at all times be aware of what is going on
With feedback, the longer the job;the more detail on the status you can provide the better
Dealing with long delaysOther parts of the interface should still work, should be possible to pause long jobs
Reliance on "good" connectivityNot everyone has a fast or reliable connection, "Lengthy downloads actually change users' perception of the quality of the content
How to deal with Connectivity-Related DelaysProvide appropriate feedback, the content that is downloading should be meaningful, Enable offline operations

Design Principles pt2

Question Answer
Mapping #4Relate controls to the intuitive understanding of how they should be used
Two metrics from "Instrumental interaction"Degree of Integration, Degree of compatibility
Degree of Integration exampleScrollbars and mouse yield a 1/2, ********* would yield a 3/2
Degree of CompatibilitySimilarity between physical action and response of the object. Ex dragging object has high degree of compatibility
Consistency #5Need to be the same throughout the interface
Need to consider both appearance and interation

Consistent appearance

Consistent interaction
Consistent appearanceConsistent language/terminology, consistent graphics
Consistent interactionConsistent results i.e same commands will always have the same results and, Consistent input consistent syntax across complete system.
Inconsistency leads toUser frustration, increased learning time, Errors and disorientation (web)
Affordance #6Appearance indicates how the object should be used ex chair for sitting knobs for turning etc.
Can use metaphors to suggest affordances... But remember affordances may not transfer from physical to digital world
WIMP interface windows icons menus pointers

Design Principles pt3

Question Answer
Simplicity #7Common task should be easy to perform, Use the minimum amount of visual information to effectively communicate design goals,leads to quick recognized and understood functionality, also promotes memorability therefore less to remember
Simplicity principalsMinimize number of controls and graphical elements, Include only those that are necessary Eliminate, or relegate others to secondary windows, minimize clutter
Matching #8A match between the system and real world i.e speak the users language, any terminology should be based on user's language for the task
Matching principleUse meaningful mnemonics (a device such as a pattern of letters, ideas, or associations that assists in remembering something.), icons, and abbreviations
Minimize memory load #9Computers are good at remembering things, people are not. Promote recognition over re-call, use chunking to reduce short-term memory load
Diagnose / Recover from errors #10No matter how good your design is, users will make errors.
Types of errorsMistakes, slips.
Mistakesconscious deliberations that lead to an error instead of the correct solution
Slipsunconscious behavior that gets misdirected en route to satisfying a goal, e.g. drive to store, end up in the office shows up frequently in skilled behavior often arises from similarities of actions

Slips and its types of errors

Question Answer
Capture errorFrequently done activity takes charge instead of one intended
When does capture error occurwhen common and rarer actions have same initial sequence.
Ex telling someone your cell number instead when you intended to give work number.

Clicking 'ok' in a delete file when you don't want to delete it
Description errorIntended action has much in common with others that are possible. Usually occurs when right and wrong objects physically near each other Ex pour milk into bowl instead of glass,
move file to trash instead of to folder
Loss of activationForgetting what the goal is while undergoing the sequence of actions ex
Start going to room and forget why you are going there

navigating menus/dialogs and can't remember what you are looking for
Mode errorsPeople do actions in one mode thinking they are in another
refer to the file that's in a dif directory

look for commands / menu options that are not relevant
General rules when designing for slipsPrevent slips before they occur, Detect and correct slips when they occur, Allow for user correction through feedback and undo

Design Principles pt4

Question Answer
Recover from errorsGag, Warn, Self-correct
Gagdeals with errors by preventing the user from continuing, Ex. Can't continue until correct password is entered
Warnwarn people that an unusual situation is occurring when overused, becomes an irritant
Self-correctsystem guesses legal action and does it instead but incorrect guessing leads to trust issues.
Generic System responses for errorsDo nothing, Let's talk about it, Teach me, Error msg
Do nothingillegal action just doesn't do anything
Let's talk about itsystem initiate dialog with user to come up with solution to the problem
Teach mesystem asks user what the action was supposed to have meant and then becomes a legal one
Error msgs guidelines Have a positive tone avoid using INVALID, BAD, FATAL
Be specific and address the problem in users terms

Put users in control-> tell them what they should do

Use a consistent interface and comprehensible format

Auio should not be embarrasing

Design Principles pt5

Question Answer
Control and freedom #11Users do not like to feel trapped by the computer, should offer an easy way out of as many situations as possible
StrategiesCancel Button, Undo, Interrupt, Quit, Defaults, Ways to enable/disable automatic features.
Flexibility #12Shortcuts, accelerators, navigation jumps, type-ahead, history systems.
Acceleratorscommand completion, menu shortcuts, function keys
Navigation jumpsgoing to window/page/location directly, and avoiding intermediate nodes
Type-aheadentering input before the system is ready for it
Provide Help #13Help is not a replacement for bad design, However there are many ways to offer proper help
Types of help you should provideTutorials and on-line tours, Manuals, Reminders, context sensitive help.


Question Answer
What is a good way to create structureGestalt principles, items are grouped according to hierarchy, and allignement
Good way to order and group itemsMust be intuitive have, natural order, generics followed by details, required data followed by optional, and related objects before unrelated
is it better to align controls or labelscontrols
Sum upGestalt principles leverage properties of perception to create structure
Consider content and intended meaning when making grouping and alignment decisions

Create hierarchies to facilitate scanning

Grids help organize screens and promote consistency


Question Answer
How do people move around and between features of an interfacePeople have to navigate from a system state toward their goal
Goal seekingWhen user initially starts something with local knowledge only and are super attentive and conscious and as they get better it becomes more intuitive when navigating
Design goal for better goal seekingtry to avoid, minimize chances of big detours
Rules of navigationknowing where you are, knowing where you are going, knowing where you've been
For website navigationimportant to be easily distinguished on which website you are, since users can enter from anywhere
Breadcrumbstype of secondary navigation scheme that reveals the user's location in a website or a web application.
Examples of where have you been methodchanging the blue links from purple
Navigating hierarchiesdeep is difficult, users get disoriented, the optimal way is to have many items on each screen (logically related ) BUT THEY MUST BE WELL STRUCTURED
Problems between application and websitesStyle issues where platform stds and consistency are an issue.


Question Answer
Implementation issues covered in HCIEvents and event handling, Layout, and MVC
What are some positives about event systemsDistributed and isolated coding, Standardized events - develop an API and re-use it, Less worrying about core loop and other simultaneous tasks, Live changes
Types of eventsdevice events, GUI events, Window events, Programmer-defined events
Event informationExact nature of event information depends on event type, toolkit, windowing system
Common information in an event recordEvent type, Event time, State of modifier keys (e.g., Alt, Shift, Ctrl)
Event-specific informationMouse location, button state (mouse events), Key pressed/released , Window/component affected
Containment Hierarchy or interactor tree Components can be contained within other components
Used to determine where to send an event
Bubbling vs CapturingKnow your system and choose the right one
BubblingDirects an event to its intended target, it works like: A button is clicked and the event is directed to the button. If an event handler is set for that object, the event is triggered. If no event handler is set for that object, the event bubbles up (like a bubble in water) to the objects parent
CapturingOpposite of bubbling it goes through the document first and then works its way down, trickling
Positional Dispatchthe item pointed by the positioning device (mouse, touch, etc) gets the event
Focused dispatchthe item with "focus" gets the event
Focusa way of indicating the current active widget, usually shown visually can be modified programatically

Layout Computation

Question Answer
Two components of interface layout1. Determining optimal visual layout 2.Applying algorithms that maintain that desired visual layout through resizes of window
Some layout challengesWindow arrangement (size and pos) is not known when you build interface, Display resolution is not known, Sometimes the content of window will not be known
Layout goalswindows are dynamic, can be re-sized
When resizing we wish to maintain Consistency in interface presentation, Preserve affordances communicated through interfaces layout, preserve overall visual layout found to be ideal in user testing.
Main concerns of maintaining layoutmust implemented to support consistency and preserve affordances either manually or dynamic
Problems with manual or fixed layoutIt does not handle Resizing, and does not handle automatically generated, or variable interface content
Advantages of fixed layoutSimplicity
What is the process of dynamic layoutSpecifying components, Specifying desired constraints for the components and their relationship with respect to one another, Attempting to satisfy those constraints
General variants for a dynamic layoutIntrinsic size, Variable intrinsic layout, struts and springs
Intrinsic sizeSize of component is determined by the size of the children (ask each child for its desired size, grow component until it fits the sum of sizes)
How to combat size on containers that can grow too large for the available screencascading menus and scrollbars
Variable intrinsic layoutThe layout determined in bottom-up and top-down phases
Bottom-up phaseContainer asks each child for its preferred, min, max sizes, and values used to partition the container's space
Top-down phaseChildren are sized and told to lay themselves out in space specified
Struts and SpringsLayout specified by marking things that should remained fixed vs. those that can stretch
Strutdefines a fixed length (width/height)
Springdefines a space that "pushes" on nearby edges (specifies variable relationship)
Advantages of Struts and SpringsAn easily accessible metaphor for people performing layout
Disadvantages of Struts and SpringsWithout the right tool support, constraints can be difficult to manage, Can end up with over constrained interface

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