CSSE Requirements

Transcription

1 CSSE Requirements Steve Chenoweth Department of Computer Science & Software Engineering RHIT Session 5 Wed, July 11, 2007 Part A Above The new generation of products is becoming more difficult to understand and use. As a result, users become more frustrated, unhappy and less productive. Large portions of functionality in the complicated software products and consumer electronics go unused, and products often fail in the consumer world due to their unnecessarily complicated user interfaces. The solution to this growing problem lies in an interdisciplinary approach bounded by three core interests: Human, Technical and Aesthetic. From 1

2 Today Get back exams Review supplementary specs, demo prototypes. Intro to Interaction Design (ID). How can users be modeled? 2

3 Review supplementary specs, Supplementary spec -- demo prototypes What was easy to do, using the format? What was tough? How long (big) are they? Did your sources understand these? Prototypes Let s see them! Easy or hard to compare to Req as you see them? Stay tuned for our next exercise, where we ll use them 3

4 Intro to Interaction Design (ID) Using the other book from now on Tonight Ch 1-4 The authors web site ( has a full sets of slides to go with the chapters Tonight s would be 173 slides! I chose to select some and merge them in here 4

5 How can users be modeled? Let s look at the assignment for this week Goals are: Model users Get good data to revise your requirements and/or prototype Output will be two documents: Interviews data from those Interaction Design, with sections: Strategy (Process) Predicted Mental Model Resulting Mental Model Additional User Requirements Unknowns, Risks and To-Do s Note the proposed deadline, 1 week We ll start working on this, during class 5

6 How can users be modeled? ID, Ch 1 Step 1 What s Interaction Design and why do we need it? Basic problem Engineers specify and build interfaces for people without ever being trained to do that And, it does make a difference ID, Ch 1 6

7 Bad designs Elevator controls and labels on the bottom row all look the same, so it is easy to push a label by mistake instead of a control button People do not make same mistake for the labels and buttons on the top row. Why not? ID, Ch 1 From: 7

8 Why is this vending machine so bad? Need to push button first to activate reader Normally insert bill first before making selection Contravenes well known convention From: ID, Ch 1 8

9 Good design Marble answering machine (Bishop, 1995) Based on how everyday objects behave Easy, intuitive and a pleasure to use Only requires one-step actions to perform core tasks ID, Ch 1 9

10 Good and bad design What is wrong with the Apex remote? Why is the TiVo remote so much better designed? Peanut shaped to fit in hand Logical layout and colorcoded, distinctive buttons Easy to locate buttons ID, Ch 1 10

11 What to design Need to take into account: Who the users are What activities are being carried out Where the interaction is taking place Need to optimize the interactions users have with a product So that they match the users activities and needs ID, Ch 1 11

12 Understanding users needs Need to take into account what people are good and bad at Consider what might help people in the way they currently do things Think through what might provide quality user experiences Listen to what people want and get them involved Use tried and tested user-centered methods ID, Ch 1 12

13 What is interaction design? Designing interactive products to support the way people communicate and interact in their everyday and working lives Sharp, Rogers and Preece (2007) The design of spaces for human communication and interaction Winograd (1997) ID, Ch 1 13

14 Goals of interaction design Develop usable products Usability means easy to learn, effective to use and provide an enjoyable experience Involve users in the design process ID, Ch 1 14

15 Working in multidisciplinary Many people from different backgrounds involved teams Different perspectives and ways of seeing and talking about things Benefits more ideas and designs generated Disadvantages difficult to communicate and progress forward the designs being create ID, Ch 1 15

16 The User Experience How a product behaves and is used by people in the real world the way people feel about it and their pleasure and satisfaction when using it, looking at it, holding it, and opening or closing it every product that is used by someone has a user experience: newspapers, ketchup bottles, reclining armchairs, cardigan sweaters. (Garrett, 2003) Cannot design a user experience, only design for a user experience ID, Ch 1 16

17 Why was the ipod user experience such a success? ID, Ch 1 17

18 What is involved in the process of interaction design Identifying needs and establishing requirements for the user experience Developing alternative designs to meet these Building interactive prototypes that can be communicated and assessed Evaluating what is being built throughout the process and the user experience it offers ID, Ch 1 18

19 Core characteristics of interaction design Users should be involved through the development of the project Specific usability and user experience goals need to be identified, clearly documented and agreed at the beginning of the project Iteration is needed through the core activities ID, Ch 1 19

20 Why go to this length? Help designers: understand how to design interactive products that fit with what people want, need and may desire appreciate that one size does not fit all e.g., teenagers are very different to grown-ups identify any incorrect assumptions they may have about particular user groups e.g., not all old people want or need big fonts be aware of both people s sensitivities and their capabilities ID, Ch 1 20

21 Are cultural differences important? 5/21/1960 versus 21/5/1960? Which should be used for international services and online forms? Why is it that certain products, like the ipod, are universally accepted by people from all parts of the world whereas websites are reacted to differently by people from different cultures? ID, Ch 1 21

22 Usability goals Effective to use Efficient to use Safe to use Have good utility Easy to learn Easy to remember how to use ID, Ch 1 22

23 Activity on usability How long should it take and how long does it actually take to: Using a DVD to play a movie? Use a DVD to pre-record two programs? Using a web browser tool to create a website? QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. ID, Ch 1 23

24 Back to your assignment Goals are: Model users Get good data to revise your requirements and/or prototype First, let s characterize what these users are, in your case: Users who interact with an interface built into the system itself. Experts or stakeholders who will react to the technical aspects of your prototype. People who are involved in the process you ve defined and will step through that. Or? Then, let s list all the users 24

25 Back to your assignment Now, which of these would be most important to each of them? Effective to use Efficient to use Safe to use Have good utility Easy to learn Easy to remember how to use That s a start on modeling them! 25

26 User experience goals satisfying aesthetically pleasing enjoyable supportive of creativity engaging supportive of creativity pleasurable rewarding exciting fun entertaining provocative helpful surprising motivating enhancing sociability emotionally fulfilling challenging boring annoying frustrating cutsey ID, Ch 1 26

27 Design principles Generalizable abstractions for thinking about different aspects of design The do s and don ts of interaction design What to provide and what not to provide at the interface Derived from a mix of theory-based knowledge, experience and common-sense ID, Ch 1 27

28 Design principle example: Affordances: to give a clue Refers to an attribute of an object that allows people to know how to use it e.g. a mouse button invites pushing, a door handle affords pulling Norman (1988) used the term to discuss the design of everyday objects Since has been much popularised in interaction design to discuss how to design interface objects e.g. scrollbars to afford moving up and down, icons to afford clicking on ID, Ch 1 28

29 Usability principles Similar to design principles, except more prescriptive Used mainly as the basis for evaluating systems Provide a framework for heuristic evaluation ID, Ch 1 29

30 Usability principles (Nielsen 2001) Visibility of system status Match between system and the real world User control and freedom Consistency and standards Help users recognize, diagnose and recover from errors Error prevention Recognition rather than recall Flexibility and efficiency of use Aesthetic and minimalist design Help and documentation ID, Ch 1 30

31 How can users be modeled? ID, Ch 2 Step 2 Understanding and conceptualizing interaction Basic problem Engineers don t use concepts to picture what their users are doing And, this, too, makes a difference ID, Ch 2 31

32 A framework for analysing the problem space Are there problems with an existing product or user experience? Why do you think there are problems? How do you think your proposed design ideas might overcome these? When designing for a new user experience how will the proposed design extend or change current ways of doing things? Start with defining the Problem Statement, as in Req generally ID, Ch 2 32

33 From problem space to design space Having a good understanding of the problem space can help inform the design space e.g., what kind of interface, behavior, functionality to provide But before deciding upon these it is important to develop a conceptual model This may be different from the rest of engineering. Right away, you try to design something, build prototypes, etc. Why? ID, Ch 2 33

34 Conceptual model Need to first think about how the system will appear to users (i.e. how they will understand it) A conceptual model is: a high-level description of how a system is organized and operates. (Johnson and Henderson, 2002, p. 26) ID, Ch 2 34

35 What is and why need a conceptual model? Not a description of the user interface but a structure outlining the concepts and the relationships between them Why not start with the nuts and bolts of design? Architects and interior designers would not think about which color curtains to have before deciding where the windows will be placed in a new building Enables designers to straighten out their thinking before they start laying out their widgets (p. 28) Provides a working strategy and a framework of general concepts and their interrelations ID, Ch 2 35

36 Conceptual model Need to first think about how the system will appear to users (i.e. how they will understand it) A conceptual model is: a high-level description of how a system is organized and operates. (Johnson and Henderson, 2002, p. 26) ID, Ch 2 36

37 Main components Major metaphors and analogies that are used to convey how to understand what a product is for and how to use it for an activity. Concepts that users are exposed to through the product The relationships between the concepts e.g., one object contains another The mappings between the concepts and the user experience the product is designed to support ID, Ch 2 37

38 A classic conceptual model: the spreadsheet Analogous to ledger sheet Interactive and computational Easy to understand Greatly extending what accountants and others could do ID, Ch 2 38

39 Interface metaphors Designed to be similar to a physical entity but also has own properties e.g. desktop metaphor, search engine Exploit user s familiar knowledge, helping them to understand the unfamiliar Conjures up the essence of the unfamiliar activity, enabling users to leverage of this to understand more aspects of the unfamiliar functionality People find it easier to learn and talk about what they are doing at the computer interface in terms familiar to them ID, Ch 2 39

40 Activity A company has been asked to design a computer-based system that will encourage autistic children to communicate and express themselves better. What type of interaction would be appropriate to use at the interface for this particular user group? ID, Ch 2 40

41 Back to your assignment Goals are: Model users Get good data to revise your requirements and/or prototype Output will be two documents: Interviews data from those Interaction Design, with sections: Strategy (Process) Predicted Mental Model Let s work on this one! What s a metaphor for your system, to your users? 41

42 Interaction types Instructing issuing commands using keyboard and function keys and selecting options via menus Conversing interacting with the system as if having a conversation Manipulating interacting with objects in a virtual or physical space by manipulating them Exploring moving through a virtual environment or a physical space ID, Ch 2 42

43 Instructing Where users instruct a system by telling it what to do e.g., tell the time, print a file, find a photo Very common interaction type underlying a range of devices and systems A main benefit of instructing is to support quick and efficient interaction good for repetitive kinds of actions performed on multiple objects ID, Ch 2 43

44 Vending machines Describe the conceptual model underlying the two vending machines Which is easiest to use? ID, Ch 2 44

45 Conversing Like having a conversation with another human Differs from instructing in that it more like two-way communication, with the system acting like a partner rather than a machine that obeys orders Ranges from simple voice recognition menu-driven systems to more complex natural language dialogues Examples include search engines, advice-giving systems and help systems ID, Ch 2 45

46 Pros and cons of conversational model Allows users, especially novices and technophobes, to interact with the system in a way that is familiar makes them feel comfortable, at ease and less scared Misunderstandings can arise when the system does not know how to parse what the user says e.g. child types into a search engine, that uses natural language the question: How many legs does a centipede have? and the system responds: ID, Ch 2 46

47 ID, Ch 2 47

48 Manipulating Exploit s users knowledge of how they move and manipulate in the physical world Virtual objects can be manipulated by moving, selecting, opening, and closing them Tagged physical objects (e.g., bricks, blocks) that are manipulated in a physical world (e.g., placed on a surface) can result in other physical and digital events ID, Ch 2 48

49 Manipulatives (PicoCrickets) ID, Ch 2 49

50 Direct manipulation Shneiderman (1983) coined the term Direct Manipulation Came from his fascination with computer games at the time Proposes that digital objects be designed so they can be interacted with analogous to how physical objects are manipulated Assumes that direct manipulation interfaces enable users to feel that they are directly controlling the digital objects ID, Ch 2 50

51 Core principles of DM Continuous representation of objects and actions of interest Physical actions and button pressing instead of issuing commands with complex syntax Rapid reversible actions with immediate feedback on object of interest ID, Ch 2 51

52 Why are DM interfaces so enjoyable? Novices can learn the basic functionality quickly Experienced users can work extremely rapidly to carry out a wide range of tasks, even defining new functions Intermittent users can retain operational concepts over time Error messages rarely needed Users can immediately see if their actions are furthering their goals and if not do something else Users experience less anxiety Users gain confidence and mastery and feel in control ID, Ch 2 52

53 What are the disadvantages with DM? Some people take the metaphor of direct manipulation too literally Not all tasks can be described by objects and not all actions can be done directly Some tasks are better achieved through delegating rather than manipulating e.g., spell checking Moving a mouse around the screen can be slower than pressing function keys to do same actions ID, Ch 2 53

54 Exploring Involves users moving through virtual or physical environments Examples include: 3D desktop virtual worlds where people navigate using mouse around different parts to socialize (e.g., Second Life) CAVEs where users navigate by moving whole body, arms, and head physical context aware worlds, embedded with sensors, that present digital information to users at appropriate places and times ID, Ch 2 54

55 A virtual world ID, Ch 2 55

56 Back to your assignment Goals are: Model users Get good data to revise your requirements and/or prototype Output will be two documents: Interviews data from those Interaction Design, with sections: Strategy (Process) Predicted Mental Model Let s work on this one some more! Which of the 4 Interaction Types would best fit your problem? 56

57 Theories, models and frameworks Are used to inform and inspire design A theory is a well-substantiated explanation of some aspect of a phenomenon A model is a simplification of some aspect of human computer interaction intended to make it easier for designers to predict and evaluate alternative designs A framework is a set of interrelated concepts and/or a set of specific questions ID, Ch 2 57

58 Main differences Theories tend to be comprehensive, explaining human computer interactions Models tend to simplify some aspect of human computer interaction Frameworks tend to be prescriptive, providing designers with concepts, questions, and principles to consider ID, Ch 2 58