ERD In Software Engineering: A Visual Perception Of Central Heating System Version 10 (CHCV10) Essay.

There are special extensions to the structured approach to deal with real-time systems. Study guide three identifies a real-time system as “…a system that has to respond to external events in a pre-defined maximum time interval. Hencesuch systems differ from the normal software system in that their temporal performance forms part of their equirements”.

This assignment asks you to individually provide the requirements analysis specification for an example of a real-time
system. You will be required to complete Data Flow Diagrams (DFDs) and Entity Relationship Diagrams (ERDs) as  well as include RT-SASD modifications and components including Control Flow Diagram extensions (CFDs), updates to Process Specifications (PSPECs) and Data/Requirements Dictionary as well as Control Specifications (CSPECs) (using combinational or sequential FSMs as required and presented in an appropriate format as Process Activation Tables (PATs) and/or State Transition (Machine) Diagrams (STDs)).

Assumptions

Krishna, (2011), ERD in software engineering explains the process of diagrammatic representation of features, relations and entities of an object. This offers the relationships for database in software development system. Pictured below is a visual perception of Central Heating System Version 10 (CHCV10). It represents how the inner parts of the system relates with the outer parts environment.

 

Assumptions  

• Every subsystem control panel has more than one or zero operators.
• Gas supply comes from one and only one supply pipe.
• In the Entity Relationship diagram the supplied gas to the room is pumped with one or more pipes
• The central heating system has only one control panel board. This control panel coordinates system activities.

Laplante & Ovaska, (2012).

Context Diagram

Pressman, (2010), context diagram explains particular boundaries in a particular setting or system.

Assumptions

• There exists physical entities in the system such as gas supply pipes, clock system,
• This CHCV10 is the explained system in the assignment as Heating Water Company
• CHCV10 provides boundaries in the system.

Data and Control Flow Diagram

Assumptions made

• Gas filling source information from temperature system
• Operations such as stop, start controls the heating system
• Manual control system receive information from operator 

CFD Gas Duct Control System

Process Specification Description

Kopetz, (2011), gives a description that a process specification is a method used to document, analyse and explain decision making logic and formulas used to produce data from the input procedures information. The method essentially flows downwards specifying engineering needs and techniques. Our CHSV10’s language is as outlined below.

Gas Meter Supply

Read gas_level

If(gas_supply_tank<100% and gas_supply_level >15%)

            Gas_supply_level_status = true

Else

Gas_supply_level_status = false

Heating Duct

if pipe duct closed manually

            then

                        open it manually again

                        else if

                                    heating duct system closed by CHCSV10

                        then

                                     open heating duct system  by CHCSV10

                        end if

            if central heating system working

            then

                        pipe duct system report status

                        else if

                                    no status report

                        end if

            if new active status determined

            then

                        display new status alerts

            else

                        display latter status

end

System Clock

if power energy is available

            then

                        clock system  always on

            else if

            power energy  backup available

            then

                        clocking system is always on

end

Temperature Detector System

if power available

            then

                        temperature detector system is on

                        else if

                                    power backup energy available

                        then

                                    temperature detector System on

                        end if

            if central system working

                        then

                                    temperature detector system send temperature status alerts to monitor display

            else

                        no temperature alerts display

            end

Heating Unit

if

            <50% of pipe ducts are open

            then

                        heating system turned on

            else if

                        room temperature falls below minimum required

                        then room heated

            until    

                        room temperature measured is above range

            else

                        no heating alert displayed

            then

                        heating system is turned on manually

end

System control

if

            time of the day is between 12:00:00 am and 5:59:00 am

            then

                        room temperature range of 5 to 10 degrees Celsius maintained

            else

                        turn on heating system

                        else if

                                    time of the day is between 7:00:00 am 5:59:00 pm

                        then

            room temperature of 15 to 20 kept constant

                        else if

time of the day is between 6:00:00 pm and 11:59:00 pm

                        then

                                    room temperature of 5 and 10 kept constant

                        else if

                                    manual heating is set to certain temperature

                                    then override automatic heating system

                        until

                                    heating system  is scheduled to turn on

                        else if

                                    Fan and Heating unit are turned on

            then

                        turn on automatic heating system

                        else

            heating system shows updated room temperature status

end

Control Specifications (CSPECs)

Kendall & Kendall, (2014), terms Control Specifications as the considerations of a physical production method. Hatley & Pirbhai, ‎(2013), CSPECs simulates system behavior from diverse level of operation to another level. The Control Specifications for our CHCSV10 is as follows:

State machine

Schedules actions
Timing out	0	0	0	0	0	1
Screen Monitor event status finished	0	0	0	1	0	0
Invoke/Deactivate heating system	0	1	0	0	0	0
Signal of Temperature	0	0	0	0	1	0
Gas notification	0	0	1	1	0	0
System Control and Screen Monitor	0	1	0	0	1	1
Sensor activity	0	0	0	0	1	0
Start or Stop	0	1	0	0	0	0
Display action status Incomplete	0	0	1	0	0	0
Show statuses and messages	1	0	1	1	1	1
User Interruption	1	0	0	1	0	1

Water Heating Company CHCSV10 Data Dictionary.

Chung et al, (2012), describes a data dictionary as a description of informational objects in a data modelling. Data dictionary is of benefits to coders who use data dictionaries as a point of reference during their programming activities. Below is our CHCSV10 data dictionary.

Data Structure
Gas from gas pump	Required volume Required temperature
	Flow rate as needed
Normal gas	Naturally supplied gas
Warm gas	heated gas=
	------- Flow rate: as adjusted in m/s
	Temperature: as required in degrees Celsius
	Volume: as required

 

Gas supplied in the room	Volume: as required Temperature: as needed in degrees Celsius
	Flow rate: as adjusted

 

Supplied gas	Supplied gas =
	---------
	Volume : as required Flow rate: as required
	Other versions: filtered or unfiltered

References

Agarwal, B. B., Tayal, S. P., & Gupta, M. (2010). Software engineering and testing. Jones & Bartlett Learning.

Chung, L., Nixon, B. A., Yu, E., & Mylopoulos, J. (2012). Non-functional requirements in software engineering (Vol. 5). Springer Science & Business Media.

Hatley, D., & Pirbhai, ‎. (2013). Strategies for Real-Time System Specification. Boston: Addison-Wesley.

Kendall, K.E. & Kendall, J.E. (2014). Systems Analysis and Design (9th Ed.). Harlow, England: Pearson Education Inc.

Kopetz, H. (2011). Real-time systems: design principles for distributed embedded applications. Springer Science & Business Media.

Krishna, C. M. (2011). Real?Time Systems. Wiley Encyclopedia of Electrical and Electronics Engineering. Northcutt, J. D. (2014). Mechanisms for reliable distributed real-time operating systems: The Alpha Kernel (Vol. 16). Academic Press.

Laplante, P. A. & Ovaska, S. J. (2012). Real-Time Systems Design and Analysis: Tools for the Practitioner

Pressman, R.S. (2010). Software Engineering: A Practitioners Approach (7th Ed.). McGraw-Hill. ISBN: 978-007-126782-3