Kang Chang Ryong

4 분 소요

O/X

short answer

화면에서 HCI적 property를 찾아내고 왜 그런지 설명하고 논리만 맞으면 ok

최대한 많이 쓸 것

textual Notations

  • Grammars
  • Production rules
  • Communication Sequential Process (CSP) and event algebras


Textual - Grammars

  • Regular expressionssel-line click click* double-click
    • Equivalent expressiveness to JSD
    • Good for certain kinds of dialogue such as command line syntax
  • BNF (Backus Normal Form) expr ::= empty | atom expr | ‘(‘ expr ‘)’ expr
    • More powerful than regular exp. or STNs
    • Iteration through recursive definitions
    • Still NO concurrent dialogue


(사진 슬라이드)

Production Rules

더 사람 말에 가까움

  • Unordered list of rules
  • If condition then action
    • Conditions: user initiated events and current state
    • Actions: response to user or change to system’s state
      • E.g. Select-line -> start-line <highlight ‘line’>
      • ​ Click start-line -> rest-line <rubber band on>
    • Two forms:
      • Event based: firing a rule removes its conditions from memory
      • State based: memory changed only if action explicitly specifies
        • state의 이름만 바꾸면서
  • Every rule always potentially active
    • Good for concurrency
    • Bad for sequence


Event based Production Rules

  • if condition then action Sel-line null -> first C-point first -> rest C-point rest -> rest D-point rest -> < draw line >
  • Note:
    • Events added to list of pending events
    • ‘first’ and ‘rest’ are internally generated events
  • Bad at state!
    • Permanent status information is difficult to represent.


Propositional Production System

  • State based
  • Attributes:
    • Mouse: { mouse-off, select-line, click-point, double-click }
    • Line-state: { menu, first, rest }
  • Rules (feedback not shown):
    • select-line -> mouse-off, first
    • click-point, first -> mouse-off, rest
    • click-point, rest -> mouse-off, rest
    • double-click, rest -> mouse-off, menu
  • Bad at events!


Communication Sequential Process (CSP) and Process Algebras

  • Used in Alexander’s SPI (Specification, Prototyping and Interaction), and Agent notation
  • Good for sequential dialogues
    • Bold-tog = select-bold? -> bold-on -> select-bold? ->bold-off -> Bold-tog
    • Italic-tog = . . .
    • Under-tog = . . .
  • And concurrent dialogue
    • Dialogue-box = Bold-tog   Italic-tog   Under-tog
  • But causality unclear


Syntactic Dialogue Notations - Summary

  • Diagrammatic
    • STN, JSD, Flow charts
  • Textual
    • Grammars, Production rules, CSP
  • Issues
    • Event based vs. State based
    • Power vs. Clarity
    • Model vs. Notation
    • Sequential vs. Concurrent


Semantics - Alexander SPI (i)

  • Two part specification:
    • EventCSP - Pure dialogue order
    • EventISL - Target dependent semantics
      • * ISL: Interaction Specification Language
  • Dialogue description – Centralized
  • Syntactic/Semantic trade-off – Tolerable


Semantics - Alexander SPI (ii)

  • EventCSP Login = login-mess -> get-name -> Passwd Passwd = passwd-mess -> (invalid -> Login [ ] valid -> Session)
  • EventISL

event: login-mess prompt: true out: “Login:” event: get-name uses: input set: user-id = input event: valid uses: input, user-id, passwd-db wgen: passwd-id = passwd-db(user-id)


Semantics - Raw Code

  • Event loop for word processor
  • Dialogue description
    • very distributed
  • Syntactic/Semantic trade-off
    • terrible!

image-20221010161007079


Action Properties

  • Completeness
    • Only a subset of the full set of actions are allowed for any state.
    • But what about missed actions, not shown on the diagram?
    • Unforeseen circumstances: need to know the consequences of all actions under any event and account for them.
    • For each state/action pair, the designer ought to decide what the behavior will be.
  • Determinism
    • Several arcs for one action
    • Deliberate: application decision
    • Accident: production rules
    • e.g. Nested escapes or actions may be dependent on guard conditions
  • Consistency
    • We expect the same action in different states to do the same effect
    • e.g. modes and visibility


Checking Properties (i)

  • Completeness
    • Double-click in circle states?

image-20221010161050271


State Properties

  • Reachability
    • Can you get anywhere from anywhere?
    • And how easily
    • 클릭 몇 번으로 이 state에서 저 state까지 갈 수 있는가
  • Reversibility
    • Can you get to the previous state?
    • But NOT undo (undo랑 다름)
    • 이전 state로 다시 가는데 어떤 방식으로 갈 수 있나?
      • flow를 따라서
  • Dangerous states
    • Some states you don’t want to get to
    • Some states must be made difficult to reach (disk format !)
    • Dangerous states can’t be determined automatically
    • The move to dangerous states must be different from other sequences (not-consistent!)


Checking Properties (ii)

  • Reversibility:
    • To reverse select `line’
    • Click-Double click - Select ‘graphics’
    • (3 actions)
  • N.B. not undo
    • if you want multiple line without leaving this menu?

image-20221010161121552


Checking Properties (ii)

  • Reversibility:
  • To reverse select `line’
  • Click

image-20221010161138154


Checking Properties (ii)

image-20221010161149994


Checking Properties (ii)

image-20221010161158809


Dangerous States

image-20221010161207295

  • ESC는 아무 기능이 없는데 만약 autosave를 reset하는 기능을 넣어버렸다면?? (다음 슬라이드에서 설명)


Dangerous States (ii)

  • Exit with/without save => dangerous states
  • Duplicate states - semantic distinction

image-20221010161227837

  • F1-F2 - exit with save
  • F1-Esc-F2 - exit with no save


Lexical Issues

위 예제 처럼 esc에 그런 기능이 있으면 합리적으로 보이나 몇 가지 문제가 있음

  • Visibility
    • Differentiate modes and states
      • save를 하고 나갈 수 있는지 save를 못하고 나갈 수 있는지 알 수 있는 방도가 있는지
        • 즉, esc가 눌렸었는지 check가 되나
    • Annotations to dialogue
  • Style
    • Command based- verb noun (e.g. delete files)
    • Mouse based - noun verb (e.g. move files to trashcan)
    • 이런 consistency가 마구 섞여 있으면 dangerous state로 넘어갈 여지를 많이 남기는 것
  • Layout
    • Not just appearance …


Layout Matters

  • Word processor - Dangerous states

image-20221010161302697

  • Old keyboard - OK
    • 멀리 떨어져 있음

image-20221010161310313


  • New keyboard layout
    • esc가 구석이 있긴 한데 바로 옆에 function키가 바로 옆에 있음…

image-20221010161320965

  • image-20221010161358843


  • New keyboard layout

​ image-20221010161411316

image-20221010161422298


Dialogue Analysis - Summary

  • Semantics and dialogue
    • Attaching semantics
    • Distributed/centralized dialogue description
    • Maximizing syntactic description
  • Properties of dialogue
    • Action properties: completeness(또 다른 방법 있는지), determinism(분기), consistency
    • State properties: reachability(도달 할 수 있는 state를 만들고 있는지), reversibility, dangerous states
  • Presentation and lexical issues
    • Visibility, style, layout
    • N.B. not independent of dialogue


Digital Watch – User Instructions

  • Two main modes
  • Limited interface
    • 3 buttons: A, Up, Downimage-20221010161520494
  • Button A
    • Changes mode
  • Button Up/Down
    • Changes Time/Alarm


Digital Watch – User Instructions

  • Dangerous states
    • Unintended setting
    • Guarded …by two second hold
  • Completenessimage-20221010161549989
    • From where to setting?
    • From setting to where?
    • Distinguish depress A and release A(2초 동안 누르면 어떻게 됨?)
    • What do they do in all modes?


Digital Watch – Designers Instructions

  • and …
  • That’s just one button to change modesimage-20221010161621281

눌렀다 놓기 -> stop watch

누른 상태에서 2초 버티면 알람 setting으로

  • 알람 상태에서 2초 버텨도 time setting으로 넘어감

dialog로 설계한 예제임(dangerous 고려, 등등)

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