Pairing-based identification schemes

We propose four different identification schemes that make use of bilinear pairings, and prove their security under certain computational assumptions. Each of the schemes is more efficient and/or more secure than any known pairing-based identification scheme

Invertible Carnot Groups

We characterize Carnot groups admitting a 1-quasiconformal metric inversion as the Lie groups of Heisenberg type whose Lie algebras satisfy the $J^2$-condition, thus characterizing a special case of inversion invariant bi-Lipschitz homogeneity. A more general characterization of inversion invariant bi-Lipschitz homogeneity for certain non-fractal metric spaces is also provided.Comment: 10 pages. Revised version in which the proof of Theorem 1.1 is clarifie

Transitive bi-Lipschitz group actions and bi-Lipschitz parameterizations

We prove that Ahlfors 2-regular quasisymmetric images of the Euclidean plane are bi-Lipschitz images of the plane if and only if they are uniformly bi-Lipschitz homogeneous with respect to a group. We also prove that certain geodesic spaces are bi-Lipschitz images of Carnot groups if they are inversion invariant bi-Lipschitz homogeneous with respect to a group.Comment: To appear in the Indiana University Mathematics Journa

What Have Two Decades of British Economic Reform Delivered?

Beginning in 1979 with the newly electted Thatcher Government and continuing under successive Conservative and Labour Governments, the United Kingdom has embarked on a two-decade-long experiment in economic reform. We present evidence that the reform process has succeeded in making the UK more market-friendly than its European competitors. In fact, by the 1990s Britain ranked near the top of the league tables for freedom of markets, in some cases even ahead of the United States. To evaluate the effects of these reforms we compare trends in macroeconomic outcomes in the UK relative to the US, Germany, and France. During the 1980s and 1990s Britain halted the relative declines in GDP per capita and labour productivity that had characterized earlier decades, and partially closed the gap in income per capita with France and Germany. These gains were mainly attributable to relative rises in employment and hours. Unlike its EU competitors, Britain was able to achieve high employment-population rates with rising real wages for workers. The case that the change in economic performance can be credited to market-oriented reforms is harder to prove. Nevertheless, based on our own macro-level analyses, and micro-level evidence from several companion studies, we conclude that economic reforms contributed to halting the nearly century-long trend in relative economic decline of the UK relative to its historic competitors, Germany and France.

Mind-reading versus neuromarketing: how does a product make an impact on the consumer?

Purpose – This research study aims to illustrate the mapping of each consumer’s mental processes in a market-relevant context. This paper shows how such maps deliver operational insights that cannot be gained by physical methods such as brain imaging. Design/methodology/approach – A marketed conceptual attribute and a sensed material characteristic of a popular product were varied across presentations in a common use. The relative acceptability of each proposition was rated together with analytical descriptors. The mental interaction that determined each consumer’s preferences was calculated from the individual’s performance at discriminating each viewed sample from a personal norm. These personal cognitive characteristics were aggregated into maps of demand in the market for subpanels who bought these for the senses or for the attribute. Findings – Each of 18 hypothesized mental processes dominated acceptance in at least a few individuals among both sensory and conceptual purchasers. Consumers using their own descriptive vocabulary processed the factors in appeal of the product more centrally. The sensory and conceptual factors tested were most often processed separately, but a minority of consumers treated them as identical. The personal ideal points used in the integration of information showed that consumers wished for extremes of the marketed concept that are technologically challenging or even impossible. None of this evidence could be obtained from brain imaging, casting in question its usefulness in marketing. Research limitations/implications – Panel mapping of multiple discriminations from a personal norm fills three major gaps in consumer marketing research. First, preference scores are related to major influences on choices and their cognitive interactions in the mind. Second, the calculations are completed on the individual’s data and the cognitive parameters of each consumer’s behavior are aggregated – never the raw scores. Third, discrimination scaling puts marketed symbolic attributes and sensed material characteristics on the same footing, hence measuring their causal interactions for the first time. Practical implications – Neuromarketing is an unworkable proposition because brain imaging does not distinguish qualitative differences in behavior. Preference tests are operationally effective when designed and analyzed to relate behavioral scores to major influences from market concepts and sensory qualities in interaction. The particular interactions measured in the reported study relate to the major market for healthy eating. Originality/value – This is the first study to measure mental interactions among determinants of preference, as well as including both a marketed concept and a sensed characteristic. Such an approach could be of great value to consumer marketing, both defensively and creatively

Economic Development and the Timing and Components of Population Growth

This paper examines the relationship between population growth and economic growth in developing countries from 1965 to 1985. Our results indicate that developing countries were able to shift their labor force from low-productivity agriculture to the higher-productivity industry and service sectors, and to increase productivity within those sectors, despite the rapid growth of their populations. We also find that at given rates of population growth, income growth is related to the time path of population growth and that population growth due to high birth and death rates is associated with slower income growth than population growth due to relatively low birth and death rates. Hence, the timing and components of population growth are important elements in the process of economic development.

Why Not Africa?

Various arguments have been used to explain Sub-Saharan Africa's economic decline. We find that a stress on investments in education as a prerequisite for more rapid growth is misplaced; that greater openness is far from sufficient to insure economic progress; that income inequality and urban bias are not so extreme as to foreclose prospects for more rapid growth and poverty alleviation; and that the constraints imposed by Sub-Saharan Africa's human and physical geography are not core explanations for the regions poor performance. If African countries can establish an institutional environment that enables individuals to gain the rewards of their investments, the alleged barriers to the region's growth should prove surmountable.