Good morning Complex Systems Applications Dr Jeyakesvan Veerasamy

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

Dr. Jeyakesavan Veerasamy: Introduction • B. E. (ECE) in CEG Guindy, Anna University, Chennai • MS and Ph. D 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 http: //www. devtopics. com/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. 10 s to 1000 s of users may use it daily. 10 s to 100 s 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 company’s lifeline! • It can be standard ERP system like SAP/People. Soft 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 airline’s 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 email 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 month’s 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! 2. 5 2 1. 5 Block% Drop% 1 0. 5 0 1 -Aug 2 -Aug 3 -Aug 4 -Aug 5 -Aug 6 -Aug 7 -Aug

Power of trending! Days 7 6 5 4 Days 3 2 1 0 Jan Feb March April May June July

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 jeyv@utdallas. edu