In 1964, Kautz and Singleton (IEEE Trans. Inform. Theory 10 (1964), 363–377) introduced the superimposed code concept. A binary superimposed code of strength s is identified by the incidence matrix of a family of finite sets in which no set is covered by the union of s others (J. Combin. Theory Ser. A 33 (1982), 158–166 and Israel J. Math. 51 (1985), 75–89). In the present paper, we consider a ...

This paper investigates the characteristics of Canadian manufacturing plants that are related to the use of advanced technologies. The data used are taken from the 1989 Survey of Manufacturing Technology and are linked to administrative data taken from the Census of Manufacturers. Technology use is defined first as incidence (whether a technology is used) and second as intensity (the number of ...

Sharp differences in time use by nativity emerge when activities are distinguished by incidence and intensity in recent U.S. data. A model with daily fixed costs for assimilating activities predicts immigrants are less likely than natives to undertake such activities on a given day; but those who do will spend relatively more time on them. Activities such as purchasing, education, and market wo...

Under the right conditions it is possible for the ordered blocks of a path design PATH(v, k, ) to be considered as unordered blocks and thereby create a BIBD(v, k, ).We call this a tight embedding.We show here that, for any triple system TS(v, 3), there is always such an embedding and that the problem is equivalent to the existence of a (−1)-BRD(v, 3, 3), i.e., a c-Bhaskar Rao Design. That is, ...

................................................................................3 Introduction Etiology........................................................................4 Incidence......................................................................6 Cost to Society................................................................6 Symptomatology...............................................