A Comparative Study of EU and US Trade Policies for Developing Countries: The Case of Agri-Food Products

Trade relations between developed and developing countries are one of the hot topics of the ongoing World Trade Organization (WTO) negotiations. The conclusion of the Cotonou Agreement between EU and African, Caribbean and Pacific countries, the introduction of the EU’s Everything But Arms initiative for the least developed countries and the United States’ African Growth and Opportunity Act for 39 African Countries, represents tangible incentives for many developing countries to continue their efforts to open their economies and build free markets. This paper analyzes the trade creating effects of EU and US trade policies as total effect, for agri-food products of developing countries in a gravity model framework. Data refer to a 10 year period: 1996-2005. The findings show larger trade creating effects of EU trade policies, especially for upper-middle income countries. Variation in trade creation, across the years, is not statistically significant, except for the low-income countries.Gross Trade Creation, Agricultural Trade Policy, Developed and Developing Countries, International Relations/Trade,

Operation Frames and Clubs in Kidney Exchange

A kidney exchange is a centrally-administered barter market where patients swap their willing yet incompatible donors. Modern kidney exchanges use 2-cycles, 3-cycles, and chains initiated by non-directed donors (altruists who are willing to give a kidney to anyone) as the means for swapping. We propose significant generalizations to kidney exchange. We allow more than one donor to donate in exchange for their desired patient receiving a kidney. We also allow for the possibility of a donor willing to donate if any of a number of patients receive kidneys. Furthermore, we combine these notions and generalize them. The generalization is to exchange among organ clubs, where a club is willing to donate organs outside the club if and only if the club receives organs from outside the club according to given specifications. We prove that unlike in the standard model, the uncapped clearing problem is NP-complete. We also present the notion of operation frames that can be used to sequence the operations across batches, and present integer programming formulations for the market clearing problems for these new types of organ exchanges. Experiments show that in the single-donation setting, operation frames improve planning by 34%--51%. Allowing up to two donors to donate in exchange for one kidney donated to their designated patient yields a further increase in social welfare.Comment: Published at IJCAI-1

Reverse-Safe Data Structures for Text Indexing

We introduce the notion of reverse-safe data structures. These are data structures that prevent the reconstruction of the data they encode (i.e., they cannot be easily reversed). A data structure D is called z-reverse-safe when there exist at least z datasets with the same set of answers as the ones stored by D. The main challenge is to ensure that D stores as many answers to useful queries as possible, is constructed efficiently, and has size close to the size of the original dataset it encodes. Given a text of length n and an integer z, we propose an algorithm which constructs a z-reverse-safe data structure that has size O(n) and answers pattern matching queries of length at most d optimally, where d is maximal for any such z-reverse-safe data structure. The construction algorithm takes O(n ω log d) time, where ω is the matrix multiplication exponent. We show that, despite the n ω factor, our engineered implementation takes only a few minutes to finish for million-letter texts. We further show that plugging our method in data analysis applications gives insignificant or no data utility loss. Finally, we show how our technique can be extended to support applications under a realistic adversary model

A Systematic Approach for Evaluating Satellite Communications Systems

The aerospace environment imposes straight opera- tive conditions so every electronic system usually needs to be validated for these. The same way, communica- tion systems need to be evaluated before their intro- duction in aerospace applications. In the paper we present a new methodology for the evaluation of com- munication systems in space applications. The meth- odology aims, by abstraction, at identifying all the critical aspects for the evaluation and at defining a standard and reusable framework in order to be appli- cable to any Communication Systems. The methodol- ogy has been applied for the evaluation of three Data Bus for satellite communications: 1553, 1-Wire and Profibus DP RS 485 based systems have been analyzed and evaluate

Dynamical symmetries and crossovers in a three-spin system with collective dissipation

We consider the non-equilibrium dynamics of a simple system consisting of interacting spin-$1/2$ particles subjected to a collective damping. The model is close to situations that can be engineered in hybrid electro/opto-mechanical settings. Making use of large-deviation theory, we find a Gallavotti-Cohen symmetry in the dynamics of the system as well as evidence for the coexistence of two dynamical phases with different activity levels. We show that additional damping processes smoothen out this behavior. Our analytical results are backed up by Monte Carlo simulations that reveal the nature of the trajectories contributing to the different dynamical phases.Comment: 6 pages, 5 figure