1. Principles of Engineering System Design Dr T Asokan asok@iitm.ac.in

2. T Asokan Principles of Engineering System Design Dr T Asokan asok@iitm.ac.in 044-2257 4707 Originating Requirements Development: Examples

4. Air bags, safety device appearing in automobiles in the early 1990’s, became the cause of death for a noticeable number of individuals. There were severe flaws in the design, testing and deployment requirements envisaged.

5. Case Study: REQUIREMENT ANALYSIS -Air Bag System Failure in the 90s- The requirements defined only a single safety scenario on which to base the design No requirement that the airbag remain undeployed during accidents at sufficiently slow speeds that no lives are in danger Test condition requirements were wrongly identified. Pre-impact braking was not taken into account Injuries due to collision with the airbag was not considered Requirements of disposal of unused or partially used bags were not identified

6. Analyse the causes of Apollo 13 disaster as an engineering system design failure and find out the faults in the requirements identification that led to the failure. Self Study

7. Tutorial A leading financial company has decided to develop a multipurpose ATM to deliver cash, accept cash, pay bills, and print pass book. For the operational phase of this machine: (a) Identify at least few operational scenarios and explain them in detail. (b) Develop an input/output trace for two scenarios. (c) Develop an external system diagram (d) Develop a set of originating requirements and prepare the ORD for the operational phase.

8. Scenario 1. Customer makes deposits Scenario 2 Scenario 3 Scenario 4 Scenario 5 Emergency situation Fire Unauthorised attempt Breakdown Theft maintenance Operational Concept Scenario

11. The system shall give an indication of the status The system shall prompt for an identification and provide opportunity to prove the identity ORIGINATING REQUIREMENTS

12. ATM System XYZ Bank Customer Unfriendly Customer ATM Admin ATM Service Providers Customer Account DB XYZ Network HW Maint. PQR Network ABC Network Fraud / Break-in Transaction Request Transaction Request Transaction Request Transaction Request Response Log in / Service Response Reports Log in / Request Retrieve Deposits Diagnostic Response Fill up w/ Cash Service Diagnostic Response Credit Card Customer Response Log in / Request Bank Management Another Bank's Customer Log in / Request Log in / Request Response

13. A leading electronics gadget manufacturer has decided to develop a multipurpose gadget to store/deliver music, store/retrieve data like address, phone number etc., and provide information on location/navigation etc. For the operational phase of this device: (a) Identify at least 10 operational scenarios and explain them in detail. (b) Develop an input/output trace for three scenarios and identify I/O requirements. (c ) Develop the external system diagram (d )Develop a set of originating requirements and prepare the ORD for the operational phase. (e) Prepare an objective hierarchy for the operational phase Group ASSIGNMENT II

14. Summary Six functions of system design process Define system level design problem – Operational Concept – External Systems – Originating Requirements – Objectives hierarchy – Documentation – Requirement management ORD

15. T Asokan Principles of Engineering System Design Dr T Asokan asok@iitm.ac.in 044-2257 4707 SOFTWARE TOOLS FOR SYSTEM ENGINEERING

16. SysML SysML is a general purpose modeling language for systems engineering applications. It is a dialect of UML™, the industry standard for modeling software-intensive systems. It supports the specification, analysis, design, verification and validation of a broad range of systems and systems-of-systems. These systems may include hardware, software, information, processes, personnel, and facilities The SysML open source specification is publicly available for download, and includes an open source license for distribution and use.open source license

17. Reproduced with permission from M/s Vitech corporation

40. Summary IT enabled system design procedures increase the efficiency of design process Commercial software are available for system design CORE, SysML etc. are standard software available for this purpose