Slide 1Good DesignSome Designs are ClassicsQuestion:Answer:So what?A really stupid ideaWhy is that stupid?Example of saving the oldPower windowsA Better Design?Actual Power Window TypesOptimizationDisintermediationExampleAnother exampleKnowledge is powerBrokers are hurtingAnd your point is?Goal driven systemsWhat goals?Business GoalsConsumer GoalsGovernment goalsGovernment exampleFitness for a purposeCase Study - AutomobilesWhat makes a great car?Tata NanoTaurus and CenturyRolls Royce and MercedesSlide 32Example of a quality designCase study: InventoryInventory goalsTraditional InventoryFundamental ProblemsGoal congruenceEffect on system designReview QuestionAnswerMore Best PracticesStudy the problem firstDefer decisionsDesign PatternsArt, Science, and EngineeringNot “Paint by numbers”And your point is…?ReviewGeorge BlankUniversity LecturerGood DesignStill an art practiced by craftsmen, not an engineering disciplineSome Designs are ClassicsQuestion:•How do you recognize a great design?Answer:•All your competitors file for bankruptcy because you took away all of their customers.So what?•How do you design great software? Very few software designers even think about driving competitors out of business when they design software.A really stupid idea•When I first studied systems analysis about 1980, many “authorities” recommended that you begin by modeling the existing system.•That is almost the worst possible way to design a system, especially in those days when computers were essentially automating existing manual systems.Why is that stupid?•Modeling the existing system almost guarantees that you will reproduce the existing system with some automation.•For example, you will probably keep some activities that are unnecessary in an automated system just because they were necessary in a manual system. Your system will be inefficient and overstaffed.•You will tend to keep all the problems of the old system and introduce new problems as well!Example of saving the oldThe mechanism that opens a car window was designed to be operated by a hand crank at a comfortable position for a person seated in the car. It is unnecessarily complex due to its off center location and the need to obtain leverage.Power windows•Most car manufacturers just put a motor where the crank was. But that required extra power, extra weight, and a stronger lever that was prone to failure.A Better Design?•With a straight toothed lever, you could use a smaller motor, save weight, save money, use less leverage, and have more reliability and better gas mileage. By saving 10 pounds per car, you could save the equivalent of one car for every 350 cars made.Actual Power Window TypesExamples from Italian Manufacturer ElectricLife WindowsScissors type Cable type Bowden typeOptimization•In a competitive economy, over time inefficient practices tend to be eliminated as business finds better (more profitable) ways to do the same things. Businesses that use the older ways tend to go broke.•But all systems can only be optimized around present resources. A good new resource, such as a computer, always changes the optimal strategy.Disintermediation•Most of the productivity gains from computers have come from disintermediation. That is a fancy term that basically means “cutting out the middleman.”•A computer is primarily a communications tool. Efficient communication allows us to avoid unnecessary tasks and costs.Example•Most large companies have flattened their hierarchies since automation, getting rid of middle managers.•The two primary tasks of middle management were to gather information from subordinates to pass on to upper management and to communicate the policies of upper management to the workers. If communication is automated, fewer people need to do it.•That is disintermediation.Another example•Small merchants are not as efficient as (good) large merchants. They can not get big discounts by ordering in truckload quantities. They survive on convenience and lack of price competition.•Around 1970, large malls started to be built all around the United States. Whenever a new mall was built, many small merchants were driven out of business.•In smaller towns, Wal-Mart had the same effect.Knowledge is power•Merchants survive by charging more for goods than they pay for them. It is to their advantage to reduce your ability to know their costs and to shop around and see what their competitors are charging.•The Internet has changed the nature of an auto dealership. Now most new car customers know what they want and how much it will cost the dealer before they buy the car. Now car dealers have to make their money where the customer lacks knowledge, on trade-in values, used cars, and the service and parts departments.Brokers are hurting•A broker is in the business of bringing buyers and sellers together. Where there are efficient communications that allow buyers and sellers to find each other without brokers, brokers have to become much more efficient to survive.•Travel agencies are in trouble, because most airline tickets are now sold direct. Since the airlines no longer need the agencies, they have reduced or eliminated commissions.And your point is?•Newspapers are threatened by the Internet. Craig’s List alone probably reduces newspaper classified ad revenues by $50 million a year.•All of these are examples of disintermediation. If disintermediation is a large part of the benefit of automation, shouldn’t designers think about it every time they design a system?Goal driven systems•A best practice in software development is to focus on stakeholder goals instead of the functions or activities to be performed by a system.•In essence, focusing on goals allows us to avoid reproducing functions that are not necessary to reach those goals. (More disintermediation!)What goals?•There are three basic types of customers in the economy.•Business•Consumers•Government•Each type has different goals.Business Goals•Business has the following goals:–More Profit–Lower Costs–Growth (in size, value, market share, pricing power)–Reduction in competition (buy them or drive them out of business)Consumer Goals•Consumers want–Economy (lower prices)–Convenience (less time)–Reliability (no hassles)–Status (style and perceived quality)–Pleasure (sex, drugs, and music?)Government goals•People in power tend to have the primary goal of remaining