Location Modeling Utilizing Maximum Service Distance Criteria

The location set-covering problem (LSCP) and the maximal covering location problem (MCLP) have been the subject of considerable interest. As originally defined, both problems allowed facility placement only at nodes. This paper deals with both problems for the case when facility placement is allowed anywhere on the network. Two theorems are presented that show that when facility placement is unrestricted, for either the LSCP or MCLP at least one optimal solution exists that is composed entirely of points belonging to a finite set of points called the network intersect point set (NIPS). Optimal solution approaches to the unrestricted site LSCP and MCLP problems that utilize the NIPS and previously developed solution methodologies are presented. Example solutions show that considerable improvement in the amount of coverage or the number of facilities needed to insure total coverage can be achieved by allowing facility placement along arcs of the network. In addition, extensions to the arc-covering model and the ambulance-hospital model of ReVelle, Toregas, and Falkson are developed and solved.     

THERMOLUMINESCENT DATING OF NEOLITHIC AND CHALCOLITHIC POTTERY FROM SITES IN CENTRAL PORTUGAL

Samples of Neolithic and Chalcolithic pottery from nine sites in the Upper Alentejo and Estremadura regions of Portugal have been dated by the thermoluminescence method (quartz inclusion technique). The project was designed to help establish an absolute chronology for the Neolithic and Chalcolithic periods in this area, and to try to elucidate the chronological relationships between settlement sites and burial sites (‘dolmens’) in the same area. Portugal was confirmed, together with Brittany, as being one of the earliest foci of megalith builders.     

DEPENDENCE OF SUPRALINEARITY ON PRE-DOSE: SOME OBSERVATIONS

Recent studies on pottery and related materials have shown there to be cases where the degree of supralinearity is dependent on the previous radiation history of the sample. Results are presented of two investigations of this variation with pre-dose: one using pottery, the other using fired feldspars. For these samples no simple form for the variation can be inferred.