Complex Systems Applications Dr. Jeyakesvan Veerasamy The University of Texas at Dallas, USA Good morning!

Dr. Jeyakesavan Veerasamy: Introduction B.E. (ECE) in CEG Guindy, Anna University, Chennai MS and PhD Computer Science, University of Texas at Dallas (UTD), USA 16 years of work experience as Telecom Software Engineer in Nortel and Samsung 10 years of online teaching & 4 years of classroom teaching – I work now as Director of final year projects & Teaching faculty in UTD. I teach 3 months a year in colleges in & around Coimbatore.

Recent software glitch in Chenani airport Chennai airport immigration system went down a few weeks ago causing several hours of delay in processing entry & exit of international passengers.

From 20 famous software disasters Error in math equation sends US rocket (Mariner 1) on a wrong path and had to be destroyed. CAD software programmer made incorrect assumption about steel roof – Hartford stadium collpased under the weight of snow. Medical equipment gave too much radiation due to race condition and killed patients.

Major characteristics of a simple system Functionality is the focus. If the software misbehaves, you can simply reset it. possibly just 1 user! possibly developed by just 1 designer too. Easy to recreate a problem and debug…

Major characteristics of a complex system Stability & performance are very important. 10s to 1000s of users may use it daily. 10s to 100s of designers were likely involved. Built on top of several modules/libraries Software bugs can take days or even weeks to recreate. Particularly, race conditions can be painful to debug. System should be load-tested, but almost impoissible to test everything (or declare bug-free!) May interwork heavily with underlying hardware.

Major Characteristics of a Complex Systems Application Lots of data flows through the system. Electronic process has replaced paper-based mechanism – it can be companys lifeline! It can be standard ERP system like SAP/PeopleSoft or proprietary/custom-built system like telecom software. Generates lot of operational data that we can use to generate reports.

Sample complex system applications Airport control tower software Flight control software Rocket control system Order management system for a big company Wireless network system for telecom operator IRCTC Indian Railway booking system Internet

Airline reservation system issue We know there are several good reasons for moving from paper-based system to computerized system for any business. One problem with paper-based system is that an employee may misplace or loose a paper. Can similar thing happen in computerized system too? I booked my flight ticket to India using airlines website. After I finalized the trip itinerary, I submitted the credit card number and completed the transaction.

Airline reservation system issue Each transaction seems to go through a few states: Booking Requested Ticketed Partially Traveled Completed Typically Requested state lasts for 1 hour to 1 day, depending on whether it is local/international and involves multiple airlines etc. For the recent India trip, I had booked the ticket 2 months prior to travel date. On the day of travel, I logged in to print my itinerary & got a shock – My booking was still in Requested state!

Airline reservation system issue There was no or phone call from the airline regarding this issue. This is equivalent to paper lost in the manual system! Airline reservation system is a high capacity commercial transaction system - it is unacceptable that orders can be lost/stuck in such manner. In addition to generating overall performance reports, all commercial systems need to have audit mechanisms to shift through all the data automatically and raise alarms when something does not look right. In this case transaction in Requested state > 3 days would be a great one to raise alarm!

Wireless Network system Lots of raw performance data is collected every day for every tower equipment. Regional and whole network reports are generated daily. Yesterday report says, Coimbatore network had 2% call blocking and 1% call drop ratio. Is it good or bad? In other words, assuming you are the area manager, do you need to do anything right away?

Order-fulfillment system Let us say the last months report says, On average, we took 5 days to produce and ship. Is it good or bad? In other words, assuming you are the COO, do you need to do anything right away? Answer: It depends. We do not know 2% call drop, 1% call block, or 5 days to process are good numbers or not.

Power of trending!

Based on the past performance, we can see right away that block% increased performance has worsened. We need to investigate and correct it ASAP. Drop ratio has improved it will be good to know why. Average # of days has improved it will be good know why. Collection of meaningful metrics is extremely crucial for any business. Tools should enable the managers to access the trend information easily.

Summary I hope you will try to get the full value of such webinars by asking questions during the webinars and participating in follow-up discussions. More automation more reliance on system applications in our lives. Complex applications can have complex issues can be painful & exciting experience!

Questions & Answers Dr. Jeyakesavan Veerasamy