SOFT 423: Software Requirements

Transcription

1 SOFT 423: Software Requirements Week 11 Class 1 Telescope Example End-to-End SOFT 423 Winter

2 Last Class CRUDO Activity Diagrams SOFT 423 Winter

3 This Class Telescope System Example We won t get into full details A look at what is done at each phase SOFT 423 Winter

4 The System Telescope Control System 24 Telescope (mirror size) SOFT 423 Winter

5 Elicitation SOFT 423 Winter

6 Interviews Doug Past President and Lead on Venour Project Tom Past Chair of ATM committee and Observing Chair SOFT 423 Winter

7 Stakeholders Amateur Telescope Making (ATM) Contacts Tom and Doug SOFT 423 Winter

8 Stakeholders Amateur Telescope Making (ATM) Contacts Tom and Doug System Team SOFT 423 Winter

9 Stakeholders Amateur Telescope Making (ATM) Contacts Tom and Doug System Team SOFT 423 Winter

10 Stakeholders Users (how many user groups?) Novice User Demanding Astrophographer Casual User Public Observing Supervisor Public Observer SOFT 423 Winter

11 Stakeholders Users (how many user groups?) Novice User Demanding Astrophographer Casual User Public Observing Supervisor Public Observer Developers and Testers SOFT 423 Winter

12 The Problem Once a proper site is found, and observatory will be built to house telescope on a permanent basis. Members want to use the scope for advanced research as well as Photography SOFT 423 Winter

13 The Problem The telescope will be used for public observing. The scope is aimed at a given celestial object and the public takes turns looking through the scope. SOFT 423 Winter

14 The Problem The scope is taken to star parties. These are gatherings of amateur and professional astronomers in remote locations. SOFT 423 Winter

15 The Problem The scope must remain mobile so that it can be used at start parties and public sessions. SOFT 423 Winter

16 The Problem The scope needs an electronic tracking system to control the scope. Astrophotography requires that the scope maintain a high pointing accuracy over minute periods SOFT 423 Winter

17 Background Research (Telescopes) Two kinds of mounts, Equatorial and Alt- Azimuth. both mounts have two axis Equatorial has one aligned with Earth s axis (i.e. on an angle), easy to track Alt-Az is often called a cannon mount local coordinates, harder to track SOFT 423 Winter

18 Background Research (Telescopes) Credit: Marie-Lan Nguyen SOFT 423 Winter

19 Background Research (Telescopes) Credit: Wikipedia user ECeDee SOFT 423 Winter

20 Background Research (Coordinates) Stellar Coordinate Systems (RA, Dec) equatorials use this Local Coordinate System (Alt,Az) alt az uses this The sky moves 360 in 23 hrs 56 minutes, seconds (360/86164 = /s) Resolution of a telescope: 4.466/D(inches) = 0.2 arc seconds ( degrees) 75 times a second... (upper limit) 40 steps a second reasonable... SOFT 423 Winter

21 Background Research (Tracking) Telescope tracking is difficult at zenith (directly overhead) (telescope must spin) need to warn user for photography public viewing Slewing speed (5 /s) Field De-rotation SOFT 423 Winter

22 Background Research (General) Three star alignment algorithm Mount errors characterization (backlash) Existing Solutions Commercial (Dobdriver II) Open Source (Mel Bartel) SOFT 423 Winter

23 Background Research (Astronomy) Celestial Object Database Messier, NGC, Stellar Names Lunar, Solar and Planetary motion planetary includes planetoid (comets) and extra-terrestrial moons. ephemeris descriptors, calculations eccentricity Meteorological considerations SOFT 423 Winter

24 Stakeholder Needs (System Team) Details of the LCD Screen (special symbols LCD screen vs Alphanumeric) Keypad Layout and Keys (do we get to label the keys, or has the system team designed the labels) SOFT 423 Winter

25 Stakeholder Needs (System Team) Details of motor drive trains Possible existence of encoders? Details of microprocessor Clock accuracy, clock drift SOFT 423 Winter

26 Stakeholder Needs (RASC Kingston) (Royal Astronomical Society of Canada) Cost/Delivery Schedule Priorities Acceptance Testing Details Ranking of functionality for schedule slippage SOFT 423 Winter

27 Stakeholder Needs (RASC Kingston) (Royal Astronomical Society of Canada) Other Details based on background research Details of User group needs based on background research SOFT 423 Winter

28 Stakeholder Needs (Developers and Testers) Feasibility: Capacity of micro controller : Stellar Database Size (need extra external disk?) reconciled with system team s hardware design Speed of Microprocessor Development time/cost estimates SOFT 423 Winter

29 Analysis Problem Domains SOFT 423 Winter

30 PDOA System Types? SOFT 423 Winter

31 PDOA System Types? Control Information Connection SOFT 423 Winter

32 PDOA System Types? Control Information Connection SOFT 423 Winter

33 Commanded Behaviour Frame Telescope Control Rules Telescope And Field Rotator Position Telescope Controller User SOFT 423 Winter

34 Control Frames Content Data model for subdomains Characteristics and innate behaviour of subdomains, causal laws Shared phenomena observed Actions that can be initiated Distortions or delays introduced by a Connection Domain Behaviour rules and valid commands Techniques Entity Relationship Diagram, Data Dictionary Text, Finite State Machines, Decision Tables Text (event list) Text (action list) Text Text, Finite State Machines, Decision Tables SOFT 423 Winter

35 Control Frames Data model for subdomains telescope position Straightforward degrees Sky Data model for celestial objects static coordinates for star and deep space objects coordinate formats for various movable celestial objects SOFT 423 Winter

36 Control Frames Characteristics and innate behaviour of subdomains, causal laws most astronomy information coordinate systems, rate of sky motion, dynamic body calculations (lunar, planet, etc.) telescope motion limitations (vertical, horizon) alt azimuth characteristics (including field rotation requirements) SOFT 423 Winter

37 Control Frames Shared Phenomena observed Three star alignment (user interaction) user fine grain control (user interaction) manual slewing internal position model (discrete control over motors) encoders SOFT 423 Winter

38 Control Frames Actions that can be initiated Position telescope horizontally Position telescope vertically internal position model (discrete control over motors) encoders SOFT 423 Winter

39 Control Frames Distortions or delays introduced by a Connection Domain We have a separate connection domain were we will look at this SOFT 423 Winter

40 Control Frames Behaviour rules and valid commands Tracking rules (translation, update frequency) Three star alignment Manual slewing Manual guiding Automatic slewing tracking while performing lookup (concurrency) User Modes (for tracking input) Reference Formal models SOFT 423 Winter

41 PDOA System Types? Control Information Connection SOFT 423 Winter

42 Information System Frames Real World Information Function Information System Reports SOFT 423 Winter

43 Information Frames Not going to go through each table entry for this one you get the idea SOFT 423 Winter

44 Information Frames Really two information systems Telescope position provides feedback to user on current position of telescope Celestial Database System Allows users to look up celestial objects and pass information to the control frame SOFT 423 Winter

45 PDOA System Types? Control Information Connection SOFT 423 Winter

46 Connection System Frames Again, there is no need to go through the table line by line. SOFT 423 Winter

47 Connection System Frames Abstracts management of telescope Control domain is user to telescope position Similar to 4 variable NAT Describes interface to motors (4 phase lines to each of alt and az, 2 phase control of field rotator) Description of Mount Errors Description of physical drive train including backlash/vibration calculations SOFT 423 Winter

48 Connection System Frames Acceleration/Deceleration Max speed of motors Max precision of motors (microstepping) SOFT 423 Winter

49 Analysis Modeling, NFR, and the Requirements Document SOFT 423 Winter

50 Representational Modeling User Display (Static) Menu Driven System for tasks such as looking up objects, Three star alignment, etc storyboard Keyboard Layout interface prototype computer program with window for display window for buttons, window with animated picture of telescope SOFT 423 Winter

51 Non-Functional Requirements Performance Slew speed SOFT 423 Winter

52 Non-Functional Requirements Capacity Number of stellar objects in database SOFT 423 Winter

53 Non-Functional Requirements Safety When tracking close to overhead, telescope must turn rapidly. What happens if random member of the public is on the ladder 12 feet in the air? Bright Objects - when skewing, what happens if we move the moon into the field of view SOFT 423 Winter

54 The Requirements Document Distill Analysis into Document Multiple User Classes (important) SOFT 423 Winter

55 Specification SOFT 423 Winter

56 Specifying the Requirements Finite State Model of some sort SCR SCR description ignores connection system Some concurrency, so multiple mode variables are required. state charts also possible SOFT 423 Winter

57 Specifying the Requirments Data model of database including both static and dynamic celestial objects DD vs ER SOFT 423 Winter

58 The Specification Document Distill into Document this example is rather easy to stay away from any premature design SOFT 423 Winter

59 Validation SOFT 423 Winter

60 Validation First things first Documents reviews Format, all the sections, etc. Make sure all of the easy stuff is taken care of. SOFT 423 Winter

61 Validation Requirements Review Meetings Doug and Tom Representative from System Team 2-3 users (different classes) A Developer A Tester SOFT 423 Winter

62 Validation Requirements Review Meetings Line by line, review the documents Produce the list of problems and agreed upon actions to resolve problems SOFT 423 Winter

63 Validation Take Action Resolve any problems found during reviews These should be fairly minor (additional information required, corrections to errors, etc.) SOFT 423 Winter

64 Validation Return the Requirements Review Meetings Same group of people Ensure that actions correctly resolve problems Read through again to ensure correctness SOFT 423 Winter

65 AND THAT S IT! SOFT 423 Winter

66 Assignment 4 SOFT 423 Winter

67 Assignment 4 Posted on Website Review of Research Paper in Software Requirements Two (2) pages IEEE Conference Format Summary of Paper Critical Assessment SOFT 423 Winter

68 Next Class More System Examples SOFT 423 Winter