Data warehouses features

The presentation of the results is highly dependent on the client tool that initiated the query. The client model is used to transform the result into a suitable form. The special process integrated features of the flowsheet tool can be used to directly insert a proper reflnement of the separation into the flowsheet. Details on the flowsheet tool and its interaction with the process data warehouse can be found in [194]. 

The Sequence Retrieval System (SRS [19]), initially developed at EMBL and the European Bioinformatics Institute, uses an interesting approach by combining the features of data warehouses and federated database systems. SRS is on the one hand heavily indexing locally stored genomic flat file databases and, on the other hand, it allows one to query DBMS on different sites. An example for a federated approach is the Mouse Federated Database of the Comparative Mouse Genomics Centers Consortium (http //www.niehs.nih. gov/cmgcc/dbmouse.htm). 

An important feature of the standard transportation problem is that it can be expressed in the form of a table, which displays the values of all the data coefficients a bj, c j) associated with the problem. In fact, the constraints and the objective function of the transportation model can be read directly from the table. A standard transportation table for three warehouses and four markets is shown in Table 2.13. 

The stochastic problem is characterised by two essential features the uncertainty in the problem data and the sequence of decisions. In our case, the demand is considered as a random variable with a certain probability distribution. The binary variables associated to the opening of a plant/warehouse as well as the continuous variables that represent the capacity of plants/warehouses are considered as first stage decisions. The fluxes of materials and the sales of products are taken as second stage or recourse variables. The objective hinctions are therefore the expected net present value and the expected consumer satisfaction. 

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