Multivariate Nonaparametric Classes in Reliability.

Multivariate nonparametric classes have been proposed as early as 1970. For background and references as well as some discussion of univariate classes with multivariate generlizations in mind see Block and Savits 1981. This paper describes only a few fundamental developments prior to 1981 and focuses on developments since then. The coverage will not be exhaustive but will emphasize the topics which the authors feel are most important. Section 2 deals with multivariate nonparametric classes. In section 2.1 multivariate IFRA is discussed with emphasis on the Block and Savits 1980 class. Multivariate NBU is covered in Section 2.2 and multivariate IFR are considered in Section 2.4 and in Section 2.5 the topics of multivariate DMRL and HNBUE are touched on.