Intradimensional single-peakedness and the multidimensional arrow problem

Arrow's account (1951/1963) of the problem of social choice is based upon the assumption that the preferences of each individual in the relevant group are expressible by a single ordering. This paper lifts that assumption and develops a multidimensional generalization of Arrow's framework. I show that, like Arrow's original framework, the multidimensional generalization is affected by an impossibility theorem, highlighting not only the threat of dictatorship of a single individual, but also the threat of dominance of a single dimension. In particular, even if preferences are single-peaked across individuals within each dimension -- a situation called intradimensional single-peakedness -- any aggregation procedure satisfying Arrow-type conditions will make one dimension dominant. I introduce lexicographic hierarchies of dimensions as a class of possible aggregation procedures under intradimensional single-peakedness. The interpretation of the results is discussed

Performance Evaluation of Optimal Ate Pairing on Low-Cost Single Microprocessor Platform

The framework of low-cost interconnected devices forms a new kind of cryptographic environment with diverse requirements. Due to the minimal resource capacity of the devices, light-weight cryptographic algorithms are favored. Many applications of IoT work autonomously and process sensible data, which emphasizes security needs, and might also cause a need for specific security measures. A bilinear pairing is a mapping based on groups formed by elliptic curves over extension fields. The pairings are the key-enabler for versatile cryptosystems, such as certificateless signatures and searchable encryption. However, they have a major computational overhead, which coincides with the requirements of the low-cost devices. Nonetheless, the bilinear pairings are the only known approach for many cryptographic protocols so their feasibility should certainly be studied, as they might turn out to be necessary for some future IoT solutions. Promising results already exist for high-frequency CPU:s and platforms with hardware extensions. In this work, we study the feasibility of computing the optimal ate pairing over the BN254 curve, on a 64 MHz Cortex-M33 based platform by utilizing an optimized open-source library. The project is carried out for the company Nordic Semiconductor. As a result, the pairing was effectively computed in under 26* 10^6 cycles, or in 410 ms. The resulting pairing enables a limited usage of pairing-based cryptography, with a capacity of at most few cryptographic operations, such as ID-based key verifications per second. Referring to other relevant works, a competent pairing application would require either a high-frequency - and thus high consuming - microprocessor, or a customized FPGA. Moreover, it is noted that the research in efficient pairing-based cryptography is constantly taking steps forward in every front-line: efficient algorithms, protocols, and hardware-solutions

MARKET STRUCTURE AND SPATIAL PRICE DYNAMICS

A method was developed with time series models to test hypotheses about the relationship between market structure and spatial price dynamics. Long-run dynamic multipliers measuring the magnitude of lagged adjustments for spatial milled rice prices were calculated from the time series model and used as the dependent variable in a regression model that included a number of factors expected to influence price determination. Results show that price adjustments were slower as regional submarket concentration increased and were faster in the regions with a higher market share. Arkansas, the state with the largest market share, was consistently a price leaderDemand and Price Analysis, Industrial Organization,

Finding optimal policies in the (S - 1, S ) lost sales inventory model with multiple demand classes

This paper examines the algorithms proposed in the literature forfinding good critical level policies in the (S-1,S) lost salesinventory model with multiple demand classes. Our main result isthat we establish guaranteed optimality for two of thesealgorithms. This result is extended to different resupplyassumptions, such as a single server queue. As a corollary, weprovide an alternative proof of the optimality of critical levelpolicies among the class of all policies.inventory;customer differentiation;multiple demand classes;rationing lost sales;stochastic dynamic programming

On the optimal management of teams under budget constraints

We study optimal wage schemes for teams, under the presence of budget constraints, in a model in which agents’ effort decisions are mapped into the probability of the team’s success. We show that (first-best) efficiency can only be attained with complex contracts that are vulnerable to ex post manipulations and off-equilibrium path violations of the budget constraints. Within the domain of simple (and budget-balanced) contracts, an interesting scheme, which treats equal members of the team unequally, emerges as optimalTeam production, budget constraints, efficiency, manipulability, impartiality

Locally finite approximation of Lie groups. II

In an earlier paper [10], we constructed a ‘locally finite approximation away from a given prime p' of the classifying space BG of a Lie group with finite component group. Such an approximation consists of a locally finite group g and a homotopy class of maps which in particular induces an isomorphism in cohomology with finite coefficients of order prime to p. The usefulness of such a construction is that it reduces various homotopy-theoretic questions concerning the space BG to the corresponding questions concerning Bπ for finite subgroups π. For example, we demonstrated in [10] how H. Miller's proof of the Sullivan conjecture concerning maps from , where π is a finite group and X is a finite-dimensional complex, can be extended to maps BG→X for G a Lie group with finite component grou