SOFT 423: Software Requirements Week 11 Class 1 Telescope Example End-to-End SOFT 423 Winter 2015 1
Last Class CRUDO Activity Diagrams SOFT 423 Winter 2015 2
This Class Telescope System Example We won t get into full details A look at what is done at each phase SOFT 423 Winter 2015 3
The System Telescope Control System 24 Telescope (mirror size) SOFT 423 Winter 2015 4
Elicitation SOFT 423 Winter 2015 5
Interviews Doug Past President and Lead on Venour Project Tom Past Chair of ATM committee and Observing Chair SOFT 423 Winter 2015 6
Stakeholders Amateur Telescope Making (ATM) Contacts Tom and Doug SOFT 423 Winter 2015 7
Stakeholders Amateur Telescope Making (ATM) Contacts Tom and Doug System Team SOFT 423 Winter 2015 8
Stakeholders Amateur Telescope Making (ATM) Contacts Tom and Doug System Team SOFT 423 Winter 2015 9
Stakeholders Users (how many user groups?) Novice User Demanding Astrophographer Casual User Public Observing Supervisor Public Observer SOFT 423 Winter 2015 10
Stakeholders Users (how many user groups?) Novice User Demanding Astrophographer Casual User Public Observing Supervisor Public Observer Developers and Testers SOFT 423 Winter 2015 11
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 2015 12
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 2015 13
The Problem The scope is taken to star parties. These are gatherings of amateur and professional astronomers in remote locations. SOFT 423 Winter 2015 14
The Problem The scope must remain mobile so that it can be used at start parties and public sessions. SOFT 423 Winter 2015 15
The Problem The scope needs an electronic tracking system to control the scope. Astrophotography requires that the scope maintain a high pointing accuracy over 10-20 minute periods SOFT 423 Winter 2015 16
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 2015 17
Background Research (Telescopes) Credit: Marie-Lan Nguyen SOFT 423 Winter 2015 18
Background Research (Telescopes) Credit: Wikipedia user ECeDee SOFT 423 Winter 2015 19
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, 4.009 seconds (360/86164 = 0.00417 /s) Resolution of a telescope: 4.466/D(inches) = 0.2 arc seconds (0.0000555 degrees) 75 times a second... (upper limit) 40 steps a second reasonable... SOFT 423 Winter 2015 20
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 2015 21
Background Research (General) Three star alignment algorithm Mount errors characterization (backlash) Existing Solutions Commercial (Dobdriver II) Open Source (Mel Bartel) SOFT 423 Winter 2015 22
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 2015 23
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 2015 24
Stakeholder Needs (System Team) Details of motor drive trains Possible existence of encoders? Details of microprocessor Clock accuracy, clock drift SOFT 423 Winter 2015 25
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 2015 26
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 2015 27
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 2015 28
Analysis Problem Domains SOFT 423 Winter 2015 29
PDOA System Types? SOFT 423 Winter 2015 30
PDOA System Types? Control Information Connection SOFT 423 Winter 2015 31
PDOA System Types? Control Information Connection SOFT 423 Winter 2015 32
Commanded Behaviour Frame Telescope Control Rules Telescope And Field Rotator Position Telescope Controller User SOFT 423 Winter 2015 33
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 2015 34
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 2015 35
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 2015 36
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 2015 37
Control Frames Actions that can be initiated Position telescope horizontally Position telescope vertically internal position model (discrete control over motors) encoders SOFT 423 Winter 2015 38
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 2015 39
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 2015 40
PDOA System Types? Control Information Connection SOFT 423 Winter 2015 41
Information System Frames Real World Information Function Information System Reports SOFT 423 Winter 2015 42
Information Frames Not going to go through each table entry for this one you get the idea SOFT 423 Winter 2015 43
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 2015 44
PDOA System Types? Control Information Connection SOFT 423 Winter 2015 45
Connection System Frames Again, there is no need to go through the table line by line. SOFT 423 Winter 2015 46
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 2015 47
Connection System Frames Acceleration/Deceleration Max speed of motors Max precision of motors (microstepping) SOFT 423 Winter 2015 48
Analysis Modeling, NFR, and the Requirements Document SOFT 423 Winter 2015 49
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 2015 50
Non-Functional Requirements Performance Slew speed SOFT 423 Winter 2015 51
Non-Functional Requirements Capacity Number of stellar objects in database SOFT 423 Winter 2015 52
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 2015 53
The Requirements Document Distill Analysis into Document Multiple User Classes (important) SOFT 423 Winter 2015 54
Specification SOFT 423 Winter 2015 55
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 2015 56
Specifying the Requirments Data model of database including both static and dynamic celestial objects DD vs ER SOFT 423 Winter 2015 57
The Specification Document Distill into Document this example is rather easy to stay away from any premature design SOFT 423 Winter 2015 58
Validation SOFT 423 Winter 2015 59
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 2015 60
Validation Requirements Review Meetings Doug and Tom Representative from System Team 2-3 users (different classes) A Developer A Tester SOFT 423 Winter 2015 61
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 2015 62
Validation Take Action Resolve any problems found during reviews These should be fairly minor (additional information required, corrections to errors, etc.) SOFT 423 Winter 2015 63
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 2015 64
AND THAT S IT! SOFT 423 Winter 2015 65
Assignment 4 SOFT 423 Winter 2015 66
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 2015 67
Next Class More System Examples SOFT 423 Winter 2015 68