Chapter 11-Minicase 1 (page 511)
Rules of thumb schedule trains in Paris
- A preliminary study concluded that DSS or MIS would not be correct approaches. Why?
Decision Support System: combines models and data of semi-structured problems with extensive user involvement. Thus considers each problem unrelated. The Paris train station solves one set of problems: dispatching – yes, with may variables.
Management Information Systems are designed to provide routine information. Should be used to report the results of dispatching: how many trains were delayed, which of the 640 routes were most affected, overtime, etc.
- The possibility of using neural computing was examined but quickly discarded. Why?
Used mostly to recognize patterns based on experience. Massive parallel process and large data sets. Outcome is mostly the “highest probability“ of a query.
It still would leave the need of dispatching to the overworked humans.
- Which of the deficiencies listed earlier cannot be removed by an expert system and why?
The expert system is an interactive system: a dispatcher needs to be present to run it. Deficiency #1 is absenteeism - not resolved. Deficiency #2 is partially solved – dispatchers under pressure should not run the system for the optimal solution, just a workable one. Deficiency #3 – again on holidays there is less decision time - get a workable solution, do not waste time searching for a better one. Deficiency #4 should be solved with MIS , not the ES. Deficiency #5 is not impossible. Dispatchers interact with the ES and can still make mistakes: in the incorrect use of the ES and in dispatching decisions. Deficiency # 5… and so on.
- Can this system be transferred to train stations in other countries? Why or why not?
Expert Systems have two main components: the engine and the expert knowledge. The engine can be used in any country, any train station. The expert knowledge or rules need to be tailor-made for each station: Paris has 30 platforms – you have? Paris has 1100 trains a day , yours ? Paris has 640 routes, yours ? Etc.
- Explain how the improvements are achieved. What is the role of dispatchers now? Do we need dispatchers at all?
The ES has the rules or operating know-how of expert dispatchers. The computer provides information on two situations. When the set of rules does provide solutions - no need for a dispatcher. When the computer does not provide a solution - the dispatcher then has to find a way to “have the train running anyway.” That is done by relaxing rules; the people leaving Paris are allowed onto the platform before the passengers on the train ending in Paris have 20 or so minutes to leave the area. Etc.
Dispatchers are needed to work the expert system: They are not replaced by the expert system.
- The ES output was designed so that the forms and information flow would look exactly the same as that of the manual systems. What is the logic of such a design?
The expert system: is a support for the work that needs to be done, thus no significant work-related training is necessary. Just computer manipulation is new.
That also reduces resistance to the use of the system. People do not use many good systems due to their resistance to change.