Simulating multiple resources

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Resource allocation works with full units. When you assign resources during design time you define if they are to be used additively (all are needed to carry out the function) or alternatively (any one is sufficient) and how many units (persons in case of human resources) are required per resource. During run-time a function is only carried out if the required number of persons for each resource is available. During execution all of these persons are bound to the function. So specifying a percentage for the usage is not really applicable here.

The priority you mention is only useful if the resources are assigned alternatively. Then it is used to decide which resource to pick when more than one is available.

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There is doesn't exist an attribute where you can specify the number of iterations for a function. If the function should be carried out more than once then this should be expressed with a structural loop, i.e. the loop should be modeled with the control flow. The maximum number of iterations can be controlled with an ERM attribute in this case.

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Working hours of a resource can be specified with a Schedule model which has to be assigned to the resource.

Hi Ralf, many thanks for the information, I have resolved the loop issue. Regarding human resources associated to the function, what is the best strategy to achieve the following:

1. The position (object) has i.e. Business Analyst position has got 10 people (number of employees) attribute. However, when executing a function i.e. Plan Business Analysis, 2 BA’s are required (number of required employees) attribute on association between position object and function object. Is this the correct approach? I would also set the Resource allocation attribute on the function to Additive, is this correct?
2. Processing times, which is the best attribute to use, Avg. processing time (AT_TIME_AVG_PRCS) or Processing time (AT_WORK_TIME)?

Many thanks for the information!

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If there are ten BAs available in the organization and two are required to perform an instance of the function then setting the attributes you mentioned is correct.

Setting the resource allocation attribute to 'additive' will advise the simulation to require all connected resources at once to carry out the function. As far as I understood your case this should be correct.

Note that you can control the type of resource allocation with the connection types as well, but the attribute takes precedence. See the topic "Optimize and control processes/strategy > Simulate processes > Valuable information > Modeling > Human resources > How do alternative and additive human resource allocations differ?" in the ARIS help.

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The processing time attribute in the Business Simulator group allows you to specify a constant time as well as a distributed one. So it is more versatile than the avg. processing time attribute in the times group. There might be other ARIS applications which only evaluate the attributes in the times group, however. So if the model is mainly created for simulation purposes I'd use the special simulation attributes. Otherwise and if distributed values are not required I'd go for the more general ones. You can also maintain both. The simulation will use the simulation-specific ones only in such a case.

Etienne,

Hope you are making progress, looks like good advice from Ralf & Cecilia. I am interested in understanding a little more about why you are simulating, the business questions and decisions you are looking to explore. If you can share some of that it would be appreciated....either on the Community or directly

Geoff

Hi Geoff, I'm comparing a traditional waterfall SDLC to an Agile (itterative) SDLC to establish the impact on resourcing. With other words if we start 40 projects where 6 of them are foundation establishement (very complex) and the rest extensions or enhancements, what will the throughput be in a Waterfall vs. Agile SDLC?