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L-superadditive structure functions

Published online by Cambridge University Press:  01 July 2016

Henry W. Block*
Affiliation:
University of Pittsburgh
William S. Griffith*
Affiliation:
University of Kentucky
Thomas H. Savits*
Affiliation:
University of Pittsburgh
*
Postal address: Department of Mathematics and Statistics, University of Pittsburgh, PA 15260, USA.
∗∗Postal address: Department of Statistics, University of Kentucky, Lexington, KY 40506, USA.
Postal address: Department of Mathematics and Statistics, University of Pittsburgh, PA 15260, USA.

Abstract

Structure functions relate the level of operations of a system as a function of the level of the operation of its components. In this paper structure functions are studied which have an intuitive property, called L-superadditive (L-subadditive). Such functions describe whether a system is more series-like or more parallel-like. L-superadditive functions are also known under the names supermodular, quasi-monotone and superadditive and have been studied by many authors. Basic properties of both discrete and continuous (i.e., taking a continuum of values) L-superadditive structure functions are studied. For binary structure functions of binary values, El-Neweihi (1980) showed that L-superadditive structure functions must be series. This continues to hold for binary-valued structure functions even if the component values are continuous (see Proposition 3.1). In the case of non-binary-valued structure functions this is no longer the case. We consider structure functions taking discrete values and obtain results in various cases. A conjecture concerning the general case is made.

Type
Research Article
Copyright
Copyright © Applied Probability Trust 1989 

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Footnotes

Supported by AFOSR Grant No. AFOSR-84-0113 and ONR Contract N00014-84-K-0084.

Supported in part by AFOSR Grant No. AFOSR-84-0013, and in part by NSF Grant RII-8610671 and the Commonwealth of Kentucky through the Kentucky EPSCoR Program.

References

Barlow, R. E. and Proschan, F. (1981) Statistical Theory of Reliability and Life Testing. To Begin With, Silver Spring, Maryland.Google Scholar
Block, H. W. and Sampson, A. R. (1985) Conditionally ordered distributions. University of Pittsburgh, Series in Reliability and Statistics, Technical Report 85–05.Google Scholar
Block, H. W. and Savits, T. H. (1982) A decomposition for multistate monotone systems. J. Appl. Prob. 19, 391402.Google Scholar
Block, H. W. and Savits, T. H. (1984) Continuous multistate structure functions Operat. Res. 32, 703714.Google Scholar
Cambanis, S. and Simons, G. (1982) Probability and expectation inequalities. Z. Wahrscheinlichkeitch. 59, 625.Google Scholar
El-Neweihi, E. (1980) A relationship between partial derivatives of the reliability function of a coherent system and its minimal path (cut) sets. Math. Operat. Res. 5, 553555.CrossRefGoogle Scholar
El-Neweihi, E. and Proschan, F. (1984) A survey of multistate system theory. Comm. Statist. A Theory Methods 13, 405432.CrossRefGoogle Scholar
El-Neweihi, E., Proschan, F. and Sethuraman, J. (1978) Multistate coherent systems. J. Appl. Prob. 15, 675688.Google Scholar
Griffith, W. S. (1980) Multistate reliability models. J. Appl. Prob. 17, 735744.CrossRefGoogle Scholar
Joag-Dev, K., Perlman, M. and Pitt, L. (1983) Association of normal random variables and Slepian's inequality. Ann. Prob. 11, 451455.Google Scholar
Kemperman, J. H. B. (1977) On the FKG-inequality measures on a partially ordered space. Proc. Kon. Ned. Akad. Wet., Series A, 80, 313331.Google Scholar
Lorentz, G. G. (1953) An inequality for rearrangements. Amer. Math. Monthly 60, 176179.Google Scholar
Marshall, A. W. and Olkin, I. (1979) Inequalities: Theory of Majorization and Its Application. Academic Press, New York.Google Scholar
Natvig, B. (1982) Two suggestions on how to define a multistate coherent system. Adv. Appl. Prob. 14, 434455.CrossRefGoogle Scholar
Tchen, A. H. T. (1980) Inequalities for distributions with given marginals. Ann. Prob. 8, 814827.Google Scholar
Topkis, D. M. (1978) Minimizing a submodular function on a lattice. Operat. Res. 26, 305321.Google Scholar