CAPÍTULO III. EL CASO DE LA PROVINCIA DE SANTA FE: LA ESTRATEGIA
4. El nivel operativo de la coordinación del Plan ABRE Aspectos de la
4.3. La generación de sinergias: una aproximación a su lectura
The cost knowledge is stored in the PlantEquipment class in the instance of the equipment concerned. This knowledge is accessed through the slot Extraincome. When this is accessed it fires methods which calculate the extra income that a piece of equipment can generate. Some of the values needed to calculate the extra income are gathered by asking the user for data or opinions of the impact of the addition of a piece equipment for time savings. Figure 6.14 shows an example of the type of input which might be asked for. This particular input is being used the help justify the benefits of
^napter o - . i^ eveiop m en t the addition of Quick Work Roll Change (QWRC). Each of the formulas used are custom created to represent the cost justification the expert uses.
Work Roll change time using porter bar Work Roll change takes 20 - 45
minutes with a porter bar and crane. With QWRC this is
reduced to 10 minutes.
OK Reset
Figure 6.14
Some of the equipment can not be justified using costs. These pieces of equipment can only be justified on quality or other grounds. The quality grounds are reported to the user, if any exist, when the equipment object is asked for the amount of extra income it can generate. Figure 6.15 shows an example of quality or other reasons why water curtains can be used.
133SP& ' • 1 Extra o utput gai
be u s e d to gene for th e addition n e d b y z irate a cc of w a te r
ok
o om rolling can >st justification cu rta in s. Figure 6.15This knowledge is only accessed if it is need to help specify which piece of equipment to recommend as the best alteration to the current mill layout.
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jLreveiopmemWhen deciding whether to add a piece of equipment to the mill, its suitability within the time and money available need to be checked. There is a facility for the user to enter the money and time available for the whole study1, together with information about time and costs for individual pieces of equipment. Once either cost or time information is entered, checks against study limits can be enabled for individual equipment. This evaluation is carried out each time the rules are fired.
6.2.12 Recommending a piece of equipment
When all of the lists have been sorted, the final part of the process of integrating the knowledge base and creating explanations is to try and recommend a piece of equipment. This is done by choosing the piece of equipment which gives the most extra income, and should ideally take into account the cost of the investment needed. This is done by asking each piece of equipment selected what extra income it can generate. If pieces of equipment give the same return on investment then the user is asked which subset of equipment they want to choose. If no equipment can be recommended the system will inform the user of this.
The system gets the list of possible equipment to recommend from the list of alternatives which should be used. If there are no values in this list then the system looks at the list of equipment which can be used.
^.napter o - jt.jl.jl m. jLJeveiopmeni
If a piece of equipment falls into the list of equipment which is 'Not Used' then it will never be 'Recommended'. It will however be left in either the ShouldBeUsed or CanBeUsed list, when the user accesses them through the explanation window. This gives the expert the opportunity to override the system in special conditions. Potentially these conditions could then be incorporated in the future.
6.2.13 Links with the rest of the system
The explanation system is linked into the rest of the system through the RunRuleLists object, its links are shown in figure 6.16. It is triggered by the user asking for an explanation by pressing the explain button. This fires a function which fires the rules in the knowledge base. It then fires a method in the 'RunRuleLists' object which then compiles the explanation and reports it to the user through a session window.
Runlists RelatedRules RunRuleLists RelatedRulesI RelatedRules2 Explanation Interlace Figure 6.16
^.napter b - r . L . u . i . u e v e io p m e n t 6.3 OUTPUTS FROM THE PROGRAM
The last stage of the consultation with the knowledge base is for the system to recommend a piece of equipment if possible. To do this the system checks to see if there is any equipment that 'should be used', or if none exists, what 'can be used'. If there is only one piece of equipment then it is recommended. Otherwise if there is more than one value then the system will evaluate which of the pieces of equipment has the best return on money invested, and recommend it. This is done by posting a message to the user informing them of the recommended value, and if there is one where the explanation of why it has been chosen.
After each consultation of the knowledge base the system produces a list of equipment which might be added to the layout. Each piece of equipment has associated with it reasons why it has been selected as a possible alteration. Figure 6.17 shows an explanation produced as part of a consultation.
Chapter b - r .L .U .r . U ev eio p m en t
R eturn C lo se
fW W R , ; ;;;• ±[ ±
Explanation The mill owner w ants to u se schedule free rolling.
The equipm ent c re a te s the possibilty for the mill owner to reduce the slab stock yard.
AMWR - Explanation
The M arket Mix contains tin plate R educed ed g e drop on the strip is needed.
AMWR - Explanation
The mill owner w ants to u se schedule free rolling.
The equipm ent c re a te s the possibilty for the mill owner to reduce the time from request until coil delivery_______________
Figure 6.17
The top right hand box is used to select the equipment which has been sorted using the meta-rules ( e.g. should be used, can be used, etc. ). The top left box contains all of the equipment which should be used to alter the current layout. After selecting a piece of equipment, the explanation is produced in the main window.
The choice of the equipment to add to the layout is left to the user. If the equipment is selected because it either 'should be used' or 'can be used' then the file which records the equipment added to the mill is updated. For each scenario there is a complete record of the figures needed by the technical programs, these provide selected results from the output of the final state of the layout. At present these are stored in the database, but the
c n a p ter - r .L .u .r . u e v e io p m e n t output can not be seen by the user. A report could be constructed which presents the figures to the user, these would be needed to produce the feasibility study. The system produces a file for each scenario which records the equipment added to the layout in the order it was added, together with any cost benefits and / or quality reasons.
There is the possibility of the system producing a variety of reports which could present some of the information needed to produce the feasibility study. For example a print which records the figures used to arrive at a cost benefit for the addition of a piece of equipment. A spreadsheet file could be produced which presents the information in a standard fashion. The feasibility study could then be written in a similar fashion using this spreadsheet. Because the system demonstrates the capability to produce a text file, it would be only a matter of modifying this format to create a spreadsheet.