Multidimensional Dominance Drawings and Their Applications

In a dominance drawing Γ of a directed acyclic graph (DAG) G, a vertex v is reachable from a vertex u if, and only if all the coordinates of v are greater than or equal to the coordinates of u in Γ. Dominance drawings of DAGs are very important in many areas of research. They combine the aspect of drawing a DAG on the grid with the fact that the transitive closure of the DAG is apparently obvious by the dominance relation between grid points associated with the vertices. The smallest number d for which a given DAG G has a d-dimensional dominance drawing is called dominance drawing dimension, and it is NP-hard to compute. In this paper, we present efficient algorithms for computing dominance drawings of G with a number of dimensions respecting theoretical bounds. We first describe a simple algorithm that shows how to compute a dominance drawing of G from its compressed transitive closure. Next, we describe a more complicated algorithm, which is based on the concept of modular decomposition of G, and obtaining dominance drawings with a lower number of dimensions. Finally, we consider the concept of weak dominance, a relaxed version of the dominance, and we discuss interesting experimental results.

If It Is Surely Better, Do It More? Implications for Preferences Under Ambiguity

Consider a canonical problem in choice under uncertainty: choosing from a convex feasible set consisting of all (Anscombe–Aumann) mixtures of two acts f and g, [Formula: see text]. We propose a preference condition, monotonicity in optimal mixtures, which says that surely improving the act f (in the sense of weak dominance) makes the optimal weight(s) on f weakly higher. We use a stylized model of a sales agent reacting to incentives to illustrate the tight connection between monotonicity in optimal mixtures and a monotone comparative static of interest in applications. We then explore more generally the relation between this condition and preferences exhibiting ambiguity-sensitive behavior as in the classic Ellsberg paradoxes. We find that monotonicity in optimal mixtures and ambiguity aversion (even only local to an event) are incompatible for a large and popular class of ambiguity-sensitive preferences (the c-linearly biseparable class. This implies, for example, that maxmin expected utility preferences are consistent with monotonicity in optimal mixtures if and only if they are subjective expected utility preferences. This incompatibility is not between monotonicity in optimal mixtures and ambiguity aversion per se. For example, we show that smooth ambiguity preferences can satisfy both properties as long as they are not too ambiguity averse. Our most general result, applying to an extremely broad universe of preferences, shows a sense in which monotonicity in optimal mixtures places upper bounds on the intensity of ambiguity-averse behavior. This paper was accepted by Manel Baucells, decision analysis.

On an Open Question Regarding When Two-Block Pricing Weakly Dominates Two-Part Tariff

Leland and Meyer showed through an example that when the distribution of consumer types is nondegenerate, there exist two-block pricing plans that yield strictly higher producer surplus than the profit maximizing two-part tariff scheme. This led them to pose the following question: does weak dominance (in the sense of profit) rather than strict dominance of two-block pricing over two-part tariff hold only when the distribution of buyer-types is degenerate? This note shows that the answer to this question is, No: even when the distribution of consumer types is continuous, it is possible that the best two-block pricing scheme performs no better than the best two-part tariff. JEL Classification: D4

Differential patterns of vocal similarity in tolerant and intolerant macaques

The investigation of vocal similarity between individuals has provided evidence of the flexibility of communication signals. This study evaluates the impact of group membership, affiliative bonds, kinship and dominance on acoustic similarity in two primate species with different social styles, intolerant rhesus macaques and tolerant Tonkean macaques. We focused on the fundamental frequencies of the contact calls emitted by adult females. Close kinship promoted vocal similarity between individuals in both species, and also group membership in Tonkean macaques, indicating the involvement of experiential and/or genetic factors. In rhesus macaques more similarities were observed between partners with strong or weak dominance asymmetry than between those with medium asymmetry, which again points to the role of experience. No evidence was found that dominance influences vocal similarity in Tonkean macaques. Our results provide additional evidence to the flexibility of vocal signals produced by macaques, and reveal that it is influenced by social style.

The Effect of Open Innovation on Technology Value and Technology Transfer: A Comparative Analysis of the Automotive, Robotics, and Aviation Industries of Korea

With the advent of the Fourth Industrial Revolution, the Korean industrial environment has been rapidly changing. As a result, several industries are facing different innovation conditions, including: the automotive industry, which is a traditional manufacturing industry in Korea; the aerospace industry, which has been vertically integrated, and has been led by a single large company—Korea Aerospace Industries—since Korea went through an economic crisis in the 1990s; and the robotics industry, which is currently emerging. This study used parameters related to patents originating from the automobile, robotics, and aerospace fields. The patents subjected to analysis were those registered in Korea from 2001 to 2014, and included those that were applied for, jointly applied for, or registered by Korean companies. This study analyzed the differences caused by the effect of open innovation in the three industries. According to our results, first, the three industries experienced different effects of open innovation. Second, when large companies controlled a given industry, open innovation either worked a little or did not work at all. According to this research result, the Korean robotics industry, which has a weak dominance of large companies, experienced a strong effect of open innovation, in that joint patent applications led to economic gains from the patents and an increase in technology transfer and technology value. The aerospace industry of Korea, which has the highest dominance of large companies, experienced a slight effect of open innovation, as the effect of joint patent application only improved the technology value. Finally, the automotive industry of Korea had an intermediate level of open innovation, between the aerospace and robotics sectors.

Multiple Aggressions Among Nestmates Lead to Weak Dominance Hampering Primitively Eusocial Behaviour in an Orchid Bee

Reproductive conflict expressed as aggression is common in social Hymenoptera. In eusocial species, as in honeybees, several mechanisms alleviate the conflicts and reduce aggressive interactions. Unlike their sister group, the orchid bees do not exhibit eusociality. Instead, most of the species seem to have lost sociality and some species have retained vestigial social behaviour. In the current study we investigated the aggressive interactions of females of Euglossa annectans Dressler through five generations of phylopatry and reuse of the natal nest. Although network analysis indicates that central individuals, those with more interactions, were more commonly the aggressors and others were more commonly the recipients, multiple attacks and several potential dominant female within the nest indicated a labile sociality. This suggests that there is an unstable social hierarchy in the species. Euglossa annectans, despite having overlapping generations, during which several individuals share a nest, there is no division of labour into reproductive and interactions are often competitive. Aggressive behaviours conducted by multiple fertile females were often followed by egg, larvae or pupae replacement.