HUMAN COMPUTER INTERACTION The User Interface-An Introduction . - Webs

BIET IT-IV Year 1 Sem (2011-2012) HCI NOTESEasier rememberingMore naturalExploits visual/spatial cuesFoosters more concrete thinkingProvides contextFewer errorsIncreased feeling of controlImmediate feedbackPredictable system responsesEasily reversible actionsLess anxiety concerning useMore attractiveMay consume less spaceReplaces national languagesEasily augmented with text displaysLow typing requirementsSmooth transition from command language system.Disadvantages:Greater design complexityLearning still necessaryLack of experimentally-derived design guidelinesInconsistencies in technique and terminologyWorking domain is the presentNot always familiarHuman comprehension limitationsWindow manipulation requirementsProduction limitationsFew tested icons existInefficient for touch typistsInefficient for expert usersNot always the preferred style of interactionNot always fastest style of interactionIncreased chances of clutter and confusionThe futz and fiddle factorMay consume more screen spaceHardware limitationsSome studies and a conclusion:- Over the past couple of decades a variety of studies havebeen performed comparing graphical systems with other interaction styles. In some usabilitystudies graphical systems were found superior, in other studies other interaction techniqueswere found superior, and in some cases no differences were found. How well the system wasdesigned was the best indicator of success, not the style of interaction. The design shouldreflect this. The design of an interface, and not its interaction style, is the best determinants of ease ofuse. User preferences must be considered in choosing an interaction style. In the overwhelming majority of cases, words are more meaningful to users than icons. The content of a graphic screen is critical to its usefulness. The wrong presentation or aPrepared By- Nazia Banu and Ch.Ramu7

BIETIT-IV Year 1 Sem (2011-2012) HCI NOTEScluttered presentation may actually lead to greater confusion, not less. The success of a graphical system depends on the skills of its designers in followingestablished principles of usability.Characteristics if the Graphical User InterfaceSophisticated visual presentationPick- and- Click InteractionRestricted set of Interface optionsVisualizationsObject Orientation:-Container objects are objects to hold other objects. There are three kindsof container objects: The workplace is the desktop, the storage area for all objects. Folders aregeneral-purpose containers for long-term storage of objects. Work areas are temporary storagefolders used for storing multiple objects currently being worked on.Device objects represent physical objects in the real world, such as printers or trashbaskets.A collection is the simplest relationship-the objects sharing a common aspect.A Constraint is a stronger object relationshipA composite exists when the relationship between objects becomes so significant that theaggregation itself can be identified as an object.A container is an object in which other objects exist.Properties or Attributes of objects:- Objects also have properties or attributes. Properties arethe unique characteristics of an Object. Properties help to describe an object and can bechanged by users.Actions:- In addition to objects are actions. People take actions on objects. They manipulateobjects in specific ways(commands) or modify the properties of objects(property or attributespecification).Prepared By- Nazia Banu and Ch.Ramu8

BIETIT-IV Year 1 Sem (2011-2012) HCI NOTESCommands are actions that manipulate objects.Property/attribute specification actions establish or modify the attributes or properties ofobjects.The following is a typical property/attribute specification sequence.The user selects an object-for example, several words of textThe user then selects an action to apply to that object, such as the action BOLD.The selected words are made bold and will remain bold until selected and changed again.Application versus Object or Data orientation;- When a text-based system was developed, itwas called an application. An application-oriented approach takes an action: object approach,like this:Action 1 .An application is opened(for example, word processing)Object 2. A file or other object selected(for example, a memo).An object-oriented object: action approach does this:Object 1. An object is chosen( a memo).Action 2. An application is selected(word processing).Views:- Views are ways of looking at an object's information. Composed views presentinformation and the objects contained within the object. Contents views list the components ofobjects. Settings views permit seeing and changing object properties. Help views provide allthe help functions.Use of Recognition Memory:- Continuous visibility of objects and actions encourages use ofperson's more powerful recognition memory.Concurrent Performance of Functions:- Graphic systems may do two or more things at onetime. Multiple programs may run simultaneously. Data may also be transferred betweenprograms. It may be temporarily stored on a "clipboard" for later transfer or be automaticallyswapped between programs.The Web User Interface:- Looking forward, interface design tools will mature, research-baseddesign guidelines will become increasingly available(and will be applied), and knowledge ofusers and their needs, will expand. Then., the ultimate goal of a Web that feels natural, is wellstructured, and is easy to use will reach fruition.The Popularity of the Web:- While the introduction of the graphical user interfacerevolutionized the user interface, the Web has revolutionized computing. Nowhere in thehistory of computing has the user been given so much control. Web usage has reflected thispopularity.User controls has had some decided disadvantages for some Web site owners as well.Users have become much more discerning about good design. Slow download times,confusing navigation, confusing page organization, disturbing animation, or other undesirablesite features often results in user abandonment of the site for others with a more agreeableinterface. People are quick to vote with their mouse, and these warnings should not gounheeded.Prepared By- Nazia Banu and Ch.Ramu9

BIETIT-IV Year 1 Sem (2011-2012) HCI NOTESCharacteristics of a Web Interface:- A web interface possess a number of characteristics, somesimilar to a GUI interface, and, as has already been shown, some different.GUI versus Web page Design:- GUI and Web interface design do have similarities. Both aresoftware designs, they are used by people, they are interactive, they are heavily visualexperiences presented through screens, and they are composed of many similar components.The following paragraphs highlight the other most significant differences. DevicesUser focusData/InformationUser tasksUser's conceptual spacePresentation elementsNavigationContext. GUIInteraction. GUIResponse timeVisual styleSystem capabilityTask efficiency. GUI'sConsistencyUser assistanceIntegrationSecurityReliabilityPrinted pages versus Web pages:- In the following paragraphs, the major differences betweenprint and web page design are briefly described. Implications for Web page design are alsosummarized. Page size Page rendering Page layout Page resolution User focus Page navigation Sense of place Interactivity Page independenceThe Merging of Graphical Business Systems and the Web:- Another strength of the Web liesin its ability to link databases and processing occurring on a variety of machines within acompany or organization. The graphical business system and the Web will merge into acommon entity. These web systems are called intranets.Characteristics of an Intranet versus the Internet;- An intranet has many of the samecharacteristics as the Internet. They differ, however, in some important ways. The followingdiscussion is partly based upon Nielsen.Prepared By- Nazia Banu and Ch.Ramu10

BIET IT-IV Year 1 Sem (2011-2012) HCI NOTESUsersTasksType of informationAmount of informationHardware and SoftwareDesign philosophyExtranets:- An extranet is a special set of intranet Web pages that can be accessed fromoutside an Organization or company.Principles of User Interface Design:- An interface must really be just an extension of aperson. It must also be easy to learn, for people want to do, not learn to do. Finally, the systemmust be easy and fun to use, evoking a sense of pleasure and accomplishment not tedium andfrustration.The interface itself should serve as both a connector and a separator: a connector in thatit ties the user to the power of the computer, and a separator in that it minimizes the possibilityof the participants damaging one another. These principles will continue to evolve, expand,and be refined as our experience with GUI and the Web increases.Principles for the Xerox STAR: The illusion of manipulability objectsVisual order and viewer focusRevealed structureConsistencyAppropriate effect or emotional impactA match with the mediumGeneral Principles: Aesthetically pleasing Clarity Compatibility User Compatibility Task and job comparability Product compatibility Comprehensibility Configurability Consistency Control Directness Efficiency Familiarity Flexibility Forgiveness Predictability Recovery ResponsivenessSimplicity;- There are several ways to minimize this complexityPrepared By- Nazia Banu and Ch.Ramu11

BIETIT-IV Year 1 Sem (2011-2012) HCI NOTES Progressive disclosureProvide defaultsMinimize screen alignment pointsMake common actions simpleProvide uniformity and consistencyTransparency:- permit the user to focus on the task or job, without concern for the mechanicsof the interface.Workings and reminds of workings inside the computer should be invisible to the user.Trade-Offs; Final design will be based on a series of trade-offs balancing often-conflicting designprinciples. People's requirements always take precedence over technical requirements.HUMAN COMPUTER INTER ACTIONUNIT -IIIDesign process- human interaction with computers, importance of human characteristicshuman consideration, human interaction speeds, understanding business junctions.The user interface Design processIn total, 14 steps are presented, beginning with know your user or client and ending with adiscussion of testing.Obstacles and pitfalls in the development pathDeveloping a computer system is never easy.Nobody ever gets it right the first timeDevelopment is chock -full of surprises.Good design requires living in a sea of changes.Making contracts to ignore change will never eliminate the need for change.Even if you have made the best system humanly possible will still make mistakes when usingit.You must have behavioral design goals like performance design goals.Common pitfalls areNo early analysis and understanding of the user's needs and expectations.A focus on using design features or components that are neat or glitzy.Little or no creation of design element prototypes.No usability testingNo common design team vision of user interface design goal.Poor communication between members of the development team.Prepared By- Nazia Banu and Ch.Ramu12

BIETIT-IV Year 1 Sem (2011-2012) HCI NOTESDesigning for people: the five commandments.Gain a complete understanding of users and their tasks.Solicit early and ongoing user involvement.Perform rapid prototyping and testing.Modify and iterate the design as much as necessary.Integrate the design of all the system components.USABILITYSimply defined usability as the capability to be used by humans easily and effectively,where,Easily to a specified level of subjective assessmentEffectively to a specified level of human performance.Usability assessment in the design processCommon usability problems Lists the 10 most common usability problems in graphical systems as reported by IBMusability specialists. They are. Ambiguous menus and icons. Languages that permit only, single-direction movement through a system. Input and direct manipulation limits. Highlighting and selection limitations. Unclear step sequences. More steps to manage the interface than to perform tasks. Complex linkage between and within applications. Lack of system anticipation and intelligence. Inadequate error messages, help, tutorials, and documentation.Characteristics particularly wasteful of peoples time, and often quite irritating, are. Visual clutter.Impaired information readability.Incomprehensible components.Annoying distractions.Confusing navigation.MYTH usability is nothing but common sense Inefficient navigationInefficient operations.Excessive or inefficient page scrolling.Information overload.Design inconsistency.Outdated information.Prepared By- Nazia Banu and Ch.Ramu13

BIET IT-IV Year 1 Sem (2011-2012) HCI NOTESStale design caused by emulation of printed documents and past systems.Some practical measures of usability. Are people asking a lot of questions or often reaching for a manual?Are frequent exasperation responses heard?Are there many irrelevant action being performed?Are their many things to ignore?Do a number of people want to use the product?Some objective measures of usabilityHow effective is the interface? Can the requited rang of tasks be accomplished: At better than some required level of performance (for example, in terms of speed anderrors.By some required percentage of the specified target range of users?Within some required proportion of the range of usage environments?How learnable is the interface? Can the interface be learned? Allowsomespecifiedpercentagevariationenvironment s beyond those first specified?intasksand/orWhat are the attitudes of the users? Are they: Within acceptable levels of human cost in terms of tiredness, discomfort, frustration,and personal effort?Such that satisfaction causes continued and enhanced usage of the system?The level of established goals will depend on the capabilities of the user, The capabilities ofthe system, and the objectives of the system.The design teamProvide a balance design team, including specialists in: Development Human factors Visual design Usability assessment Documentation Training.Step 1: know your user or clients To create a truly usable system, the designer must always do the following:Understand how people interact with computers.Understand the human characteristics important in designPrepared By- Nazia Banu and Ch.Ramu14

BIET IT-IV Year 1 Sem (2011-2012) HCI NOTESIdentify the user's level of knowledge and experienceIdentify the characteristics of the user's need's tasks, and jobs.Identify the user's physical characteristics.Identify the user's psychological characteristics.Understanding how people interact with computers Why people have trouble with computers.User of jargon.Non -obvious design.Fine distinctions.Disparity in problem -solving strategies.Design inconsistencyResponses to poor design PsychologicalTypical psychological responses to poor design are: ConfusionAnnoyance.FrustrationPanic or stressBoredomPhysical Abandonment o the system.Partial use of the system.Indirect use of the systemModification of the taskCompensatory activityMisuse of the systemDirect programming.People and their tasks.Important human characteristics in designPerception ProximitySimilarityMatching patternsSuccinctnessClosureUnityContinuityPrepared By- Nazia Banu and Ch.Ramu15

BIET IT-IV Year 1 Sem (2011-2012) HCI NOTESBalanceExpectanciesContextSignals versusMemoryMemory is not the most stable of human attributes, as anyone who has forgotten why theywalked into a room, or forgotten a very important birthday, can attest. Today, Memory is viewed asconsisting of two components, long-term and short -term (or working)Short -term, or working, memory receives information from either the senses or long termmemory, but usually cannot receive both at once, the senses being processed separately.Knowledge, experience, and familiarity govern the size and complexity of the information thatcan be remembered.Long -term memory contains the knowledge we possess. Information received in short-termmemory is transferred to it and encoded with in it, a process we call learning .it is a complex processrequiring some effort on our part. The learning process is improved if the information beingtransferred from short term memory has structure and is meaningful and familiar. Learning is alsoimproved through repetition .unlike short term memory, with its distinct limitations, with significantimplications for interface design, is the difference in ability to recognize or recall words.MAXIM minimizes the need for a mighty memory.Thus enhancing system usability includes: Presenting information in an organized, structured, familiar and meaningful way. Placing all required information for task performance in close physical proximity. Giving the user control over the pace of informationpresentation. Sensory storage.Repeated and excessive stimulation can fatigue the sensory storage mechanism,making it less attentive and unable to distinguish what important (called habituation) .avoidis unnecessarily stressing it. Design the interface so that all aspects and elements serve adefinite purpose. Eliminating interface noise will ensure that important things will be lesslikely to be missed.Visual acuityThe eye's sensitivity increases for those characters closets to the fixation point(the"0")and decreases for those characters at the extreme edges of the circle(50/50 chance exits forgetting these characters correctly identified.Foveal and peripheral visionFoveal vision is used to focus directly on something; peripheral vision senses anything in the area surroundingthe location we are looking at, but what is there cannot be clearly resolved because of the limitations in visualacuityjust described.Information processingPrepared By- Nazia Banu and Ch.Ramu16

BIETIT-IV Year 1 Sem (2011-2012) HCI NOTESOne level, the highest level, is identified with consciousness and working memory. Ti islimited, slow, and sequential, and is used for reading and understanding. You are utilizing this higherlevel now reading this book.In addition to this higher level, there exits a lower level

The User Interface-An Introduction And Overview The user interface is the most important part of any computer system. It is the system to most users. It can be seen and it can be heard and it can be touched. The goals of interface design are simple, to make working with a computer easy, productive, arid enjoyable. The Importance Of The User .