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Rank Reversals (rank + reversal)
Selected AbstractsCorrecting illegitimate rank reversals: proper adjustment of criteria weights prevent alleged AHP intransitivityJOURNAL OF MULTI CRITERIA DECISION ANALYSIS, Issue 5-6 2008Diederik J. D. Wijnmalen Abstract This note comments on a paper by Triantaphyllou (J. Multi-Crit. Decis. Anal. 2001; 10: 11,25) that attempts to demonstrate new types of rank reversal that can occur with the analytic hierarchy process (AHP). He contends that the reversals are attributable to the various types of normalization that are used with the addition step in AHP synthesis. His paper goes on to suggest that the multiplicative AHP should be used instead. This note shows that the cause of the problem is another one: AHP's independence axiom, which prohibits adjusting the criteria weights when the set of alternatives or the type of normalization change. If the criteria weights are adjusted properly, none of the rank reversals will occur. Copyright © 2009 John Wiley & Sons, Ltd. [source] Testing performance rank reversals among coexisting species: crossover point irradiance analysisFUNCTIONAL ECOLOGY, Issue 2 2003K. Kitajima First page of article [source] Effects of density and ontogeny on size and growth ranks of three competing tree speciesJOURNAL OF ECOLOGY, Issue 2 2009Suzanne B. Boyden Summary 1Rank reversals in species performance are theoretically important for structuring communities, maintaining diversity and determining the course of forest succession. Species growth ranks can change with ontogeny or in different microenvironments, but interactions between ontogeny and the environment are not well-understood because of the lack of long-term forest competition studies. While early differences in growth among species may reflect intrinsic differences in shade-tolerance and physiology, ontogenetic trends in growth and variation in neighbourhood density and composition may change or even reverse early patterns of growth rankings. 2We experimentally studied spatial and temporal patterns of species interactions and growth for three northern tree species: Larix laricina, Picea mariana and Pinus strobus. We compared species size and growth rankings over an 11-year period, for different species mixtures planted at four density levels in north-eastern Minnesota, USA. 3The benefits of different growth strategies changed with ontogeny and density leading to reversals in the size rank of competing species over time and space. High-density stands promoted dominance and resource pre-emption by L. laricina, whereas lower-density stands favoured gradual accumulation of biomass and eventual dominance by P. strobus. In the absence of strong neighbour competition, ontogenetic trends in growth had greater influence on growth patterns. 4Species interactions affected the productivity of mixed stands vs. monocultures. Species generally grew more in monoculture than when planted with P. strobus at low density, or with L. laricina at high density. Only L. laricina and P. mariana showed potential for greater overall productivity, or over-yielding, when planted together than alone, probably because of improved resource uptake by the highly stratified canopy. 5Synthesis. Density predictably determined whether size-asymmetric growth or ontogenetic growth trends would drive early establishment and growth patterns. Variation in vertical and horizontal structure that results from early competitive dynamics can influence the successional trajectory or character of the mature forest. This study extends previous efforts to identify the causes of rank reversals in communities and understand the importance of temporal changes beyond the early years of seedling establishment. [source] Correcting illegitimate rank reversals: proper adjustment of criteria weights prevent alleged AHP intransitivityJOURNAL OF MULTI CRITERIA DECISION ANALYSIS, Issue 5-6 2008Diederik J. D. Wijnmalen Abstract This note comments on a paper by Triantaphyllou (J. Multi-Crit. Decis. Anal. 2001; 10: 11,25) that attempts to demonstrate new types of rank reversal that can occur with the analytic hierarchy process (AHP). He contends that the reversals are attributable to the various types of normalization that are used with the addition step in AHP synthesis. His paper goes on to suggest that the multiplicative AHP should be used instead. This note shows that the cause of the problem is another one: AHP's independence axiom, which prohibits adjusting the criteria weights when the set of alternatives or the type of normalization change. If the criteria weights are adjusted properly, none of the rank reversals will occur. Copyright © 2009 John Wiley & Sons, Ltd. [source] Two new cases of rank reversals when the AHP and some of its additive variants are used that do not occur with the multiplicative AHPJOURNAL OF MULTI CRITERIA DECISION ANALYSIS, Issue 1 2001Evangelos Triantaphyllou Abstract Many researchers have long observed some cases in which certain ranking irregularities can occur when the original analytic hierarchy process (AHP), or some of its variants, are used. This paper presents two new categories of ranking irregularities which defy common intuition. These ranking irregularities occur when one decomposes a decision problem into a set of smaller problems each defined on two alternatives and the same criteria as the original problem. These irregularities are possible when the original AHP, or some of its additive variants, are used. Computational experiments on random test problems and an examination of some real-life case studies suggest that these ranking irregularities are dramatically likely to occur. This paper also proves that these ranking irregularities are not possible when a multiplicative variant of the AHP is used. Copyright © 2001 John Wiley & Sons, Ltd. [source] Dominance rank reversals and rank instability among male Lemur catta: The effects of female behavior and ejaculationAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009Joyce A. Parga Abstract In this study, dominance rank instability among male Lemur catta during mating was investigated. Also, data on agonism and sexual behavior across five consecutive mating seasons in a population of L. catta on St. Catherines Island, USA, were collected. Instances of male rank instability were categorized into three types. Type 1 consisted of a temporary switch in the dominance ranks of two males, which lasted for a period of minutes or hours. Type 2 dyadic male agonistic interactions showed highly variable outcomes for a period of time during which wins and losses were neither predictable nor consistent. Type 3 interactions consisted of a single agonistic win by a lower-ranked male over a more dominant male. More Type 2 interactions (indicating greater dominance instability) occurred when males had not spent the previous mating season in the same group, but this trend was not statistically significant. The majority of periods of male rank instability were preceded by female proceptivity or receptivity directed to a lower-ranked male. As such, exhibition of female mate choice for a lower-ranking male appeared to incite male,male competition. Following receipt of female proceptivity or receptivity, males who were lower-ranking took significantly longer to achieve their first agonistic win over a more dominant male than did males who were higher-ranked. Ejaculation frequently preceded loss of dominance. In conclusion, temporary rank reversals and overall dominance rank instability commonly occur among male L. catta in mating contexts, and these temporary increases in dominance status appear to positively affect male mating success. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] |