PROBLEM SOLVING & SYSTEMS

Problem Solving –Humans have always needed food, clothing, shelter and healthcare. –Early humans lived in caves and ate fruits and seeds of plants  Problems of Society –Disposal of wastes –Production of enough energy –Continuous supply of clean and safe water  Problems of Individuals –Skills in programming –Impaired vision –Sound quality of recording systems –Communication between drivers

Good Design in Problem Solving –Low-cost and easy to use –Benefits outweigh the problems  Examples –Telephones, internet, suspension bridges etc  Superconductors –Energy is lost in resistance as electricity flows –Superconductors could only be made at around –432 o F –Liquid helium was used but was too costly –Some materials work in liquid nitrogen that could go up to o F –Materials are brittle and hard to make into wire with such temperatures

Method of Problem Solving –Seven steps in problem solving  Describe the Problem –A statement describing the problem gives a way of thinking about the problem, like ‘people working for long hours get a back pain’. –This description decides whether the problem is interesting, important ---- example on page 50  Describe the Results –Goals of solving the problem should be defined –Design criteria --- list of specifications that includes all the requirements of the problem –The specifications should also include the limitations of the problem

Method of Problem Solving  Gather Information –Gathering information to solve a problem is called research –Basic research --- nature of different materials and processes –Market research --- determine if customers will like the new product  Think of Alternative Solutions –Past experience of others –Brainstorming in a group for some creative ideas –Develop alternatives by trial and error –Insight --- an idea may just pop up into your head –Some of the most important discoveries, like penicillin, have been discovered by accident

Method of Problem Solving  Choose the Best Solution –Each alternative must be examined for design criterion and constraints –Optimization --- changing or combining alternatives to improve them –Tradeoff --- selecting the best overall solution,, e.g. cost and strength of a metal  Implement the Solutions –Prototype or model of the solution is made to check for cost, risks, e.g. model of an airplane in a wind tunnel  Evaluate the Solution –Observation may suggest some improvement in design or construction of the solution --- feedback –Once satisfied, we can build the full-scale structure, or start mass- producing the product

Modeling Design Solutions –Charts and Graphs --- describe how an alternative solution might work –Mathematical Models --- use of mathematical equation to predict performance –Sketches, Illustrations, and Technical Drawings --- show ideas in picture form –Working Models --- can be partly or fully functional. Its material and size may and may not be the same as that to be used –Computer Simulation --- displays a picture of the idea on screen. It is most useful when a large number of calculations must be carried out

Real World Problems –Technological decisions must take both human needs and the protection of the environment into consideration  Social/Environmental Concerns –An airport or a nuclear plant cannot be built near a residential area –Needs of the society or the community must be considered  Politics –Groups of people have different interests, e.g. in case of a nuclear power plant –Risks of a new development should be traded for its benefits  Risk/Benefit Trade-Offs –Use of satellites, cars etc

Real World Problems  Continued Monitoring –All the effects of a technological solution may not be known until long after the solution is implemented –Some drugs may have harmful side effects  Values –Products’ advertisements have certain limitations –Some people prefer a sports car or a luxury car while others go for a basic car

Systems –A system is a means of getting a desired result, e.g. space shuttle, calculator, car etc  System Model –The input is the command we give a system or it’s the desired result –The process is the action part of a system --- it combines the resources –The output is what is produced or it’s the actual result –Feedback is information about the output that can be used to change it --- monitor --- system diagrams on page 65 and 67 –Systems with feedback are called control systems or feedback control systems or closed loop systems –Systems without feedback are called open loop systems

Systems –Even our own bodies contain systems –The body has many control systems like sugar level, heartbeat, oxygen collection etc.  Multiple Outputs –A system may produce several outputs –The outputs from a coal-burning power plant may by Expected & Desirable ~ power Expected & Undesirable ~ noise and smoke Unexpected & Desirable ~ tropical fish is flourished in the warm water Unexpected & Undesirable ~ acid rain due to the pollution  Subsystems –Many smaller systems in a large system are its subsystems