Software Dev Process
Software Dev Process CS 6300
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This 0 page Class Notes was uploaded by Alayna Veum on Monday November 2, 2015. The Class Notes belongs to CS 6300 at Georgia Institute of Technology - Main Campus taught by Staff in Fall. Since its upload, it has received 14 views. For similar materials see /class/234114/cs-6300-georgia-institute-of-technology-main-campus in ComputerScienence at Georgia Institute of Technology - Main Campus.
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Date Created: 11/02/15
Requirements Specification for the Home Heating Control System 1 Sy stem Objectives 11 The home heating control system HHCS is a software application to regulate the ow of heat to a room of a home in an attempt to maintain a temperature tr established for the room 12 The HHCS should detect and control abnormal error conditions with the aid of sensors 13 The HHCS should reduce effort and frustration in controlling the system especially by monitoring the status of combustion and fuel ow of the system 14 Minimize the waste of energy and unnecessary interruptions with predictive algorithms and similar methods 15 Increase the effective availability of individual devices for collaborative functioning by serving as a mediator between them 16 Increase awareness among those concerned of heating information such as fuel ow and the status of combustion through an informative interface 17 Maximize oil hot water home heating system utilization during the day 18 Preserve individual devices independency by providing an abstraction layer through which devices can communicate without knowledge of others 2 System Context 21 The controller will interface with the thermostats according to a de ned set of signals appropriate for the items in Appendix A table 1 and Appendix C 211 The main thermostat will provide for easy SYSTEM onoff switching and give that information to the controller via the signal labeled Heat in the aforementioned table This shall be the only thermostat to have this functionality See Appendix C for a diagram including the main thermostat 212 All thermostats will provide for easy reading of the current room temperature t and give that information to the controller via the signal t see Appendix C for a depiction 213 All thermostats will provide for easy setting of the desired room temperature tr and give that information to the controller via the variable tr 22 The controller will interface with the furnace according to the minimum set of signals de ned in Appendix A table 1 23 The controller will be able to turn the motor on and off and the motor will provide the controller with its speed The controller will be able to activate deactivate the oil value The fuel ow indicator will pass information to the controller and if there is a aw the controller will determine a fault shut the motor down and provide the main user with an error message at the central thermostat The controller will monitor the temperature of the water for internal purposes The optical sensor indicator will pass information to the controller and if there is a aw the controller will determine a fault shut the motor down and provide the main user with an error message at the central thermostat If the faults isare fixed the controller will return to the quotWait Statequot The controller will interact with a timer for shutdowns restarts and any other activities which require timed input and results 3 Functional Requirements The system operates in the following modes Dead Wait Startup Normal operation Shutdown and Error handling The operations of the system shall conform to the states in Appendix A Figure l detailed in Appendix B 31 Activating Home Heating System see Appendix B states 0 amp 1 311 313 The system shall be placed into Wait Mode operation by setting the SYSTEM Heat switch on the control panel to ON A user can set the desired temperature for a room to tr where tr is within the range of 55 to 90 degrees If no target temperature has been defined tr is defined as 72 degrees 32 Automatic Staltup of Home Heating System see Appendix B states 2 3 amp 4 321 Each room in the house that has a thermostat will be equipped with a sensor that continuously measures temperature t Ift falls below tr2 degrees in any room and SYSTEM Heat switch is ON the controller should start the system and subsequently place the system into normal operation to heat the room 323 The system should not start until the restart period currently de ned as 5 minutes has elapsed since the last shutdown The restart time is a cooloff period in which the system is disabled The owner must wait until this period has expired until the system can be started again 324 The system will not start if it is already in an Error Mode condition 325 The motor and the oil valve are activated to supply oil to the furnace 326 When the fuel speed is adequate the controller signals the ignition 327 When oil is burning in the furnace the system enters normal operation 328 Water will be warmed to the appropriate temperature currently defined as 120 degrees by burning oil in the furnace 33 Normal Operation of Home Heating System see Appendix B states 5 amp 6 331 Water is warmed until the temperature of water tW gt tp 120 degrees 332 The controller signals to open the circulation valve according to heating requirements Warmed water is pumped to the appropriate radiators in the home 333 The controller sends the signal to open circulation valves on the radiators only in rooms whose temperatures are below tr2 334 Sensors detect any abnormalities The main possible error situations are Combustion may fail to activate Fuel ow may fail to activate 335 Postcondition Room is being warmed 34 Shutdown Home Heating System see Appendix B state 7 341 A user can turn off or stop the furnace by setting the SYSTEM Heat switch to OFF at any time The controller should shut off the heating system safely through the standard shutdown procedures in section 34 when this switch is used 342 The controller first signals the furnace to stop burning 343 Within 1 second after 342 occurs the controller signals to deactivate oil delivery 344 The controller will wait at least five seconds after signaling 343 to send a signal to deactivate the motor 345 After a successful shutdown the system should be in Wait Mode unless an error has been detected for more details see the accompanying event trace in Appendix A figure 1 346 347 35 The system should provide a visible indicator to signal whether or not the furnace is running When the furnace is turned off the controller should send out a signal within 5 seconds Error handling see Appendix B state Error Sensors are equipped to monitor the following possible abnormal conditions 0 Abnormal status of combustion o Abnormal fuel ow into system In case of the abnormal conditions the controller should shut off the heating system safely according to the methods prescribed in section 34 If the optical combustion sensor signal that an abnormality has occur the system should automatically deactivated in the method prescribed in section 34 If the fuel ow sensor signals that there is no more fuel the system should automatically deactivated as per the steps in section 34 When an error is detected the controller signals to shut down ignition oil valve and circulation valve for more details see the accompanying event trace in Appendix A The system will signal the main thermostat that an error has occurred so that the thermostat may display the information to the user The system shall stay in Error Mode until the error is cleared or the SYSTEM switch is turned off placing the system in Dead Mode 4 g Qualig Requirements 41 Performance 411 The Home Heating Control System HHCS should operate with any processor which meets certain minimum requirements 4111 The processor will have a built in clock which can send a time update signal at least every tenth of a second 4112 The processor will have at least 4 kilobytes of nonvolatile memory 4113 The processor will be able to handle signals from at least 32 independent sensors 412 The controller shall operate separately from the other components and eXists as a signalhandling machine separate from other components to ensure isolation from hardware errors 4121 The HHCS will be protected using simple power clipping methods in the event that power surges occur over any signal or power lines 4122 The HHCS will have an internal feedback sensor which detects whether its operating environment is within tolerance temperature lt 120 degrees 413 The HHCS should operate with any sensors which meet minimum system requirement 4131 All temperature measurements will be accurate to a tenth of a degree 4132 All error sensors will report errors within two tenths ofa second 42 Reliability 421 The HHCS should have a MTBF of at least 30000 hours Errors from hardware subsystems do not count towards HHCS failure 422 The HHCS should log errors and store them in nonvolatile memory so that errors can be checked by service technicians 43 Usability 431 HHCS shall be compatible with any standard thermostat that allows a user to specify desired temperature and report room temperature this allows users to choose simple controls that they are familiar with from a wide selection of options 432 HHCS will support thermostats that can display an indicator when an emergency shutdown has been affected 44 Portability 441 The Home Heating Control System HHCS should be implemented in such a manner that allows for interchangeability of a given sensor type for any sensor that meets the signaling requirements 442 The HHCS will be implemented in a manner that allows for standard interface signals to simplify the design and interchangeability of newdifferent thermostat controls 443 The software portion of the HHCS will be implemented on a platform that allows easy rehosting on different hardware 45 Modifiability 451 The Home Heating Control System HHCS will be implemented using modern programming practices that maximize the maintainability and reusability of designs and code 452 The HHCS will be implemented in such a manner that allows for modular addition of new signals and control parameters without modifying the logic and structure of the design 5 Future Requirements 51 Support for an audiblevisible alarm for critical errors such as inability to cut oil ow or other combustion errors 52 Support for a programmablelearning thermostat that modi es desired temperature according to time of day or other parameters 53 Support for multiple zones fans and temperature sensors to sample different spaces in the house within each room and heat the environment more evenly 54 Support for intemet connectivity to allow users to access the controller from a web browser 55 Support for a password or similar security system to avoid unwanted user input Amendix A D ices amp Stat Figure 1 State Transition Diagram All signals except He on Stat quotDead e0 Modequot Stateerror quotError Modequot Heato Error ag n on 6 o 1 State1 09 9 State quotWait Modequot 9 quotShut off modequot MIoc off M H t o I 82w ea on tgttr 2 ortlslt5mln State2 quotWarm Up 1quot Motor On State6 quotcirculate Mode 0n Motor Speed I off bad Heaton State3 quotWarm up 2quot M On I COff HeatOn Optical Sensor Bad Appendix A Devices amp States gcont Table 1 System composition T Name Device Sensor sensor Indicator Appendix B Description of States State 0 quotDead Modequot Description The heating system is shut down Pro conditions The master heat switch is on Running Conditions The controller detects the master heat switch state If the state is off it turns off all devices motor ignition oil valve and circulation valve and indicators turnoff indication and error ag Post conditions The master heat switch is off State 1 quotWait Modequot Description The heating system is in standby mode and wait to take appropriate actions warm up handle errors or shut down according to the system parameters Pro conditions The system must be either in quotShut off modequot or quotDead modequot Running Conditions The controller receives signals and judges 1 if main heat switch is turned on 2 if there are any error signals 3 if t gt 5 seconds Post conditions Heat switch is on All devices motor ignition oil valve and circulation valve and indicators tumoff indication and error ag are turned off State error quotError Modequot Description The heating system detects error signals fuel ow and optical combustion and lights on the error ag to warn the user to clear errors In order to heat the room user should turn off and then turn on the main heat switch again Pre conditions The system is in Wait mode Running Conditions The fuel ow sensor or the optical combustion sensor detects errors Post conditions Error ag is turned on State 2 quotWarm Up 1quot Description The motor spin up to a certain speed before any further furnace actions may occur Pre conditions Before the motor may start up the system must be in state 1 quotWait modequot and a thermostat temperature t is less than or equal to temperature requested tr 2 degrees and the furnace must have been off for five minutes Running Conditions The controller monitors the motor speed As long as it is below some preset speed it will continue to speed up Post conditions The motor has reached the preset speed for ignition State 3 quotWarm up 2quot Description After the motor has reached its running speed the oil value must be opened before ignition can take place Pre conditions The motor must be at its running speed Running Conditions The controller opens the fuel value Post conditions The fuel value must be open and the fuel indicator must read fuel ow If there is no fuel ow the Fuel Flow ag is set to bad State 4 quotIgnitionquot Description The fuel owing from the tank must be ignited to warm the water for the radiator system Pre conditions The fuel value must be open with a Fuel Flow ag set to good Running Conditions Ifthe Fuel Flow ag is set to bad the system goes to the quotShut off modequot before entering quotWait modequot and then quotError Modequot Otherwise the controller will attempt to ignite the fuel If the optical sensor fails to detect an ignition the controller will try again After a certain number of failed attempts three the system will set the Optical Sensor Flag to bad and enter quotShut off modequot then quotWait modequot and nally quotError modequot Ifthe sensor detects an ignition it will set the Optical Sensor ag to good Post conditions The furnace ignited the fuel and both the Optical Sensor and the Fuel Flow ags must be good State 5 quotHeating Modequot Description Before warm water can ow through the system the water in the water tank must reach a set temperature Pre conditions The furnace must be on with both Optical Sensor and Fuel Flow ags set to good Running Conditions The furnace continues to heat the water tank Post conditions The water in the fuel tank must have reached a preset limit and both Optical Sensor and Fuel Flow ags are good State 6 quotCirculation Modequot Description Heated water is circulated to the appropriate radiators throughout the system Pre conditions The water temperature must have passed a designated threshold level for circulation The Heat switch must be on as must the motor The oil valve must be open Running Conditions The circulation valve is set to quotonquot Water continues to circulate throughout the system and is continually heated by the furnace Post conditions The environment temperature has passed the desired temperature by 2 degrees in all rooms and all circulation valves have been closed or the master heat switch has been turned off or the controller detects an abnormal condition in the fuel ow or optical sensor Sub state 6a open room valve Description Circulates water through any room where the temperature has not reached the shutoff threshold Preconditions The water temperature has reached the proper temperature for circulation the heat switch is on the motor is running and the oil valve is open In one or more of the rooms the environment temperature has dropped 2 degrees or more below the desired temperature Running Conditions In any room where the environment temperature has dropped to 2 degrees or more below the desired temperature the appropriate circulation valve is opened to allow water to ow to the radiator in that room Postconditions The desired circulation valve or valves have successfully been opened Sub state 6b close room valve Description Cuts off water circulation to any room where the temperature has passed the shut off threshold Preconditions In one or more of the rooms in which the circulation valve is open the environment temperature has risen to 2 degrees or more above the desired temperature Running Conditions In any room where the environment temperature has risen to 2 degrees or more above the desired temperature the appropriate circulation valve is closed to restrict the ow of water to the radiator in that room Postconditions The desired circulation valve or valves have successfully been closed State 7 quot Shut off Modequot Description The furnace begins the process of ceasing to heat the environment Pr quot 39 F 39 r has passed desired temperature by 2 degrees or an abnormal condition has been detected in the fuel ow or optical sensor or the master heating switch has been turned off Running Conditions The oil and circulation valves are closed after five seconds the motor is also shut off If the heating switch is off the system returns to State70 quotDead Modequot Post conditions The motor must be off and five seconds must have passed since closing the oil valve IMS Invisible Meeting Scheduler 1 System Objectives 11 The Invisible Meeting Scheduler IMS is a software application to assist in the scheduling of meetings among individuals whose schedules are available in an online calendar 12 Focus groups conducted by our marketing department show that users of time management packages would respond favorably to an IMS that satis ed or helped them satisfy the following objectives 0 121 Reduce effort and frustration in scheduling meetings especially by reducing telephone and emailtag 122 Reduce frequency of unavailable resources needed for meetings eg NV equipment 0 123 Reduce stress of rushing from one place to another 0 124 Minimize fragmentation of the working day and unnecessary interruptions 0 125 Increase the effective quot 39 quotquoty of39 J39 39J 39 for quot 39 quot activities 0 126 Increase awareness among those concerned of meeting information such as schedule updates and preparation requirements 0 127 Maximize room utilization during the work day 0 128 Preserved individuals privacy concerning aspects of their schedules that they did not want published 2 System Context 21 IMS will provide an easytouse graphical user interface GUI as part of the average user s working desktop environment which will be used for calling meetings and noti cations 22 Regular schedule information will continue to be serviced using the online calendar OLC 221 Several unconnected OLC systems may be accessible from IMS through a standard calendar interface protocol SCIP for the purposes of querying any person s or room s schedule and making reservations 23 Changes in the user population or configuration of rooms are made by administrators In most user organizations these will be HR or Facilities staff 24 The administrator is also responsible for entering customization information into IMS such as the standard working day for the user organization 3 Functional Requirements 3 1 Scheduling a meeting 311 A person calling a meeting henceforth called the Initiator will enter information into IMS about the desired meeting such as but not limited to its proposed purpose earliest and latest times at which it can usefully be held the names of desired attendees and an anticipated duration IMS shall provide defaults for missing elements 312 When the Initiator instructs IMS to schedule the meeting for which this information has been entered IMS shall obtain from those OLCs that contain schedule data for the desired attendees those attendees free times during the interval between the earliest and latest times stipulated by the Initiator IMS shall choose the earliest feasible time for the meeting that meets the constraints specified by the Initiator and the free times returned by the OLCs 313 When IMS chooses a time for a meeting it shall send queries to the OLCs for all the rooms in which the meeting could be held to ascertain which rooms are vacant during the selected time 3131 If no rooms are vacant during the selected time IMS shall choose the next feasible time 3132 IMS shall choose which room should be the venue for the meeting from the set of rooms free at the selected time by a roomchoice algorithm that shall take account of the size of the room given the number of invitees to the meeting and the convenience of the room for the invitees 314 If no feasible time exists for the meeting that meets the Initiator s constraints and the OLC schedule data for the attendees or no room is free during any of the feasible times IMS shall present the Initiator with a selection of choices including the following a Schedule the meeting based on a subset of the originally named attendees b Put the latest time for the meeting back further into the future c Abandon the scheduling of this meeting 315 If either 314 a or b is chosen IMS shall obtain from the OLC s in question further schedule data and choose the best feasible time as described above If no feasible time is found again IMS shall present the Initiator with the same choices again 316 Ifthere is at least one feasible time and IMS chooses a time for the meeting IMS shall display appropriate notification messages to the Initiator and all the invited attendees 3161 The wording of the message shall depend on whether the recipient is a the Initiator who knows about the meeting and is being informed that it has been scheduled b an invited participant who is learning about the meeting for the first time and who is being strongly invited to attend c an invited participant who was not in the subset of people whose schedules were checked when the Initiator chose option a above such invitees being weakly invited as they are known to be busy at the chosen time 317 In addition to notifying the Initiator and invited attendees IMS shall send update messages to the OLC s of the invited attendees and the room chosen as the venue these updates representing the reservation of the chosen time period for the meeting 32 Canceling a meeting 321 Only the Initiator of a meeting may normally cancel it but see 34 322 When the Initiator instructs IMS to cancel a meeting that has not yet been scheduled IMS shall abort any scheduling actions that it has started e g querying OLCs shall delete all references to the meeting and shall display a con rmation message to the Initiator 323 If the meeting to be canceled has already been scheduled IMS shall behave as speci ed in 322 and shall additionally do the following 3231 Display noti cation messages to the invited attendees informing them of the cancelation 3232 Send update messages to the OLCs for the attendees and the room chosen as the venue these update message representing the freeing of the time previously reserved for the meeting 33 Rescheduling a meeting 331 An attendee may request that a scheduled meeting be rescheduled at another time The attendee will enter the reschedule request into IMS IMS shall then display a noti cation message to the Initiator containing the attendee s request 332 When an Initiator has received a noti cation message as in 33 1 IMS shall provide options for the Initiator to continue the meeting as planned with or without the attendee to reschedule or to cancel the meeting 3321 If the Initiator decides to continue the meeting as planned and the attendee is dropped from the invitation list IMS shall record the changed attendance at the meeting and send an update message to the OLC for the attendee to free the time 3322 If the Initiator decides to continue the meeting as planned with the attendee still attending IMS shall take no action The Initiator and the attendee are assumed to work out the schedule con ict in person 3323 If the Initiator decides to reschedule the meeting IMS shall schedule the meeting as described in 31 but taking account that the earliest time as originally stipulated by the Initiator may now have passed in which case the earliest time should now default to the present time plus a default period to allow for noti cation and preparation 33231 Noti cation messages sent to attendees regarding the rescheduling of a meeting shall be worded in such a way to refer clearly to the changed schedule 3324 For cancelation see 32 34 Adding or removing a person 341 Only an administrator may add or remove a person from a system e g in the case when an employee leaves the company or is transferred to a site that is not an IMS user organization 342 When an administrator adds a person to the system IMS shall record the information about that person including name access information regular work hours work location etc for future use in scheduling decisions 343 Removal of a person from the system takes place at a time either speci ed by the administrator the effective time of the removal or by default immediately 344 When an administrator removes a person from the system IMS shall at or after the effective time remove records about that person and the person s attendance at previous meetings 345 IMS shall cancel any previously scheduled meeting that was called by the person being removed if the meeting has been scheduled to take place after the time of the person s removal 3451 Any such cancelation of a meeting in the case of the Initiator being removed from the system shall follow the description in 32 with the exception that IMS shall generate appropriate noti cation messages to explain the cancelation 346 IMS shall notify the Initiator of any meeting that a person who is being removed from the system was to attend if that meeting had been scheduled to take place after the effective time of the removal IMS shall provide the Initiator with the options to cancel the meeting or to continue with it as planned If the Initiator elects to continue the meeting as planned IMS shall take no further action If the Initiator elects to cancel the meeting IMS shall cancel the meeting as in 32 3 5 Adding or removing a room 351 Only administrators may add or remove rooms eg in the case of building work 352 When an administrator adds a room to the system IMS shall record the information about that room including name location etc for future use in scheduling decisions 353 Removal of a room from the system takes place at a time either specified by the administrator or by default immediately 354 Removal of a room may be temporary with a specified end time e g removal for the purpose of decoration or by default permanent 355 When an administrator removes a room permanently from the system IMS shall at or after the effective time remove records about that room 356 When a room is removed temporarily IMS shall retain information about the room but shall not consider it as a venue for a meeting ie IMS shall not query the room s OLC until the room is available again 357 If a meeting had been previously been scheduled to take place at a time after the permanent removal of the room or during the temporary removal of the room IMS shall attempt to relocate the room by sending queries to the OLCs of all the other convenient rooms to ascertain which if any are vacant during the scheduled time 3571 If other rooms are vacant during the scheduled time IMS shall choose a new room see 351 and shall notify the Initiator and attendees of the changed venue IMS shall also send update messages to the OLCs of the old and new venues to free and reserve the time respectively 3572 If there is no other room vacant during the scheduled time for the meeting IMS shall notify the Initiator of the need to reschedule the meeting and shall provide the Initiator with the options to cancel the meeting or to reschedule it 35721 Ifthe Initiator elects to cancel the meeting IMS shall cancel the meeting as in 32 35722 If the Initiator elects to reschedule the meeting IMS shall reschedule the meeting as in 31 with the following differences a Notification messages shall be worded in such a way to refer clearly to the changed schedule and location b The earliest time for the meeting previously stipulated by the Initiator may now have passed in which case the earliest time should now default to the present time plus a default period to allow for noti cation and preparation 4 Quality Requirements 4 1 Performance 411 If a feasible time and venue exists for a meeting IMS shall choose a time and venue and display a noti cation to the Initiator in less than half the time it would take for the Initiator to call one attendee 412 IMS shall show no visible deterioration in response time as the number of persons and rooms in the system increases 413 IMS shall require a reasonably small amount of memory so that enough of it is permanently resident to provide an Initiator and noti cation interface 414 IMS shall load as quickly as comparable productivity tools on whatever environment it is running in 4 2 Reliability 421 IMS shall be available for use as much as comparable productivity tools 43 Usability 431 IMS shall provide a user interface comparable to the UI of the OLC so that users do not have to learn a new style of interaction 432 Users will be able to understand the layout and options of the IMS UI 433 Notification messages generated by IMS shall be clear succinct and polite and free of jargon and TLAs 4 4 Portability 441 IMS will be implemented on a platform that allows easy rehosting on different hardware and OS 4 5 Modifiabili ty 451 IMS will be implemented using modern programming practices that maximize the maintainability and reusability of designs and code 452 IMS will be implemented in such a way that alternative SCIPs to the OLCs could be added easily without affecting the logic of the design