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Exercises for the Course Datawarehousing, SS 2002, Prof. R. Bayer, TUM Exercise Sheet 1 Exercise 1 , Ch.2 : Mining of mobile phone calls with schema (Caller, Callee, Time, Duration, geographic Location Caller, geographic Location Callee )
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Exercises for the Course Datawarehousing, SS 2002, Prof. R. Bayer, TUM Exercise Sheet 1 Exercise 1, Ch.2:Mining of mobile phone calls with schema (Caller, Callee, Time, Duration, geographic Location Caller, geographic Location Callee ) Identify the dimensions (there are 7 dimensions) and the measures. Design a proposal for the 7 dimensions with hierarchies for this schema and justify your design decisions. Include in the schema an estimate for the number of members per hierarchy level. For the geographic location assume that the BRD is a square of 1000 km by 1000 km and that the geographic location can be determined with a precision of 100 m. Exercise 2, Ch.3:How large is the fact table of Exercise 1 for 1 year with a relational representation in analogy to foil 5 from chapter 3, if there are 100 million calls per day in the average? What is the size of the space spanned by the dimensions? What is the sparsity of the cube? Exercise 3, Ch.4:How large is the hierarchically aggregated cube (without base table) for an aggregation up to the levels of the prefixes of calls, geographic 100*100 m squares and the time granularity of Minute? Do you think it could be computed and/or stored? Exercise 4, Ch.5:Discuss advantages and disadvantages of the various indexing techniques discussed in Ch. 5 for this application example.