Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

The “DITTY” DSS

In the DITTY Project the DSS:

• accounts for the complex time-space dynamics of the ecosystems (models);

• evaluates alternatives according to several indicators (ecological, economic, etc.);

• includes multicriteria decision algorithms driven by models and end user expertise;

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

The “DITTY” DSS

The first steps for the development of the DSS was to unify the

language and to define the structure.

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

• The control options are alternative actions, strategies and/or policies can be undertaken to affect the system behavior.

• The criteria on which the system performance led by each control option is evaluated.

• The objectives related to the criteria that the decision maker wants to optimize.

• The constraints, establishing thresholds and bounds for all the criteria in order to make the alternatives feasible or acceptable.

Terminology of the DSS

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

Structure of the DSS

Control options

Models Multicriteria Analysis

External factors

Decision

Value assignments of the control options.

In the DSS the values of control options are changed, often repeatedly, to reflect potential changes in environmental and internal factors (e.g., area dedicated to aquaculture).

External factors

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

Structure of the DSS

Control options

Multicriteria Analysis

External factors

Decision

Exogenous inputs are inputs that are not

changeable by the decision maker

(e.g., weather conditions, water inflow,

economic values, etc.)

Models

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

Structure of the DSS

Controp options

Multicriteria Analysis

External factors

Decision

Site simulation and evaluation of

indicators (correspond to decision

criteria).

Remark: The internal structure of this block is site-dependent…

indicators

Models

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

Structure of the DSS

Control options

Multicriteria Analysis

External factors

Decision

Tools supporting decision making in

situations when multiple and conflicting

objectives/criteria are present, and possibly both

qualitative and quantitative aspects need to be

considered (e.g., Analytic Hierarchy Process).

Models

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

The Analytic Hierarchy Process (AHP), [T.Saaty (1980)], is a powerful

tool that may be used to make decisions when

• multiple and conflicting objectives/criteria are present,

• both qualitative and quantitative aspects of a decision need to be

considered.

AHP is effective in dealing with complex decision making because it

reduces complex decisions to a series of pairwise comparisons.

Chiara Mocenni Roma , June 4-5, 2009Dept. Information Engineering – Centre for the Study of Complex Systems – Univ. of Siena

Application of the DSS to the Ditty sites