Situ8: browsing and capturing geolocated user-created content

The idea behind Situ8 is a simple one: enable learners to browse and/or create their own content that is geolocated, i.e. somehow related to a physical place in the “real world” (FitzGerald, 2012a). It was inspired by the popular mScape platform (Stenton et al., 2007), that enabled users to attach multimedia content to a map and deploy it through a mobile device, with such media being ‘triggered’ by a user’s geographical position, as measured by GPS (Global Positioning System) technology. However, unlike mScape, Situ8 allows both the creation and delivery of geolocated media i.e. it is a two-process

Politically Acceptable Trade Compromises Between The EC and The US: A Game Theory Approach

A model is developed to quantify the special status of agriculture in the US and the EC trade negotiations. The role of special interests are measured by a policy goals function (PGF) whose weights are estimated for each special interest group. The analysis searches for mutually acceptable, mutually advantageous trade agreements between the US and the EC using a partial equilibrium world trade model coupled with game theory. Results suggest that it is in the best interest of the US (resp. EC) 'for the EC (resp. US) to liberalize whi1e the other follows the status quo policies of 1986. Mutual gains in PGF values to both countries pursuing "large" liberalizations are unlikely to exist, although "small" liberalizations may give rise to "small" mutual gains. Altering each country's action space, and permitting compensatory payments to the most influencial groups yields trade liberalization, but free trade does not result.game theory, trade liberalization, trade negotiations, International Relations/Trade,

Bilateral Harmonization of EC and U.S. Agricultural Policies

Agricultural policies in both Europe and the United States provide commodities with an excessively high and distorted pattern of support. The economic interdependencies of the policies give rise to adverse fiscal and economic costs, which are viewed as disharmonies in the existing policy measures both within and between the two regions. Unilateral and simultaneous EC and U.S. policy changes are simulated with an international trade model. They are carried in three steps: (1) grains and feeds, (2) beef and dairy, and (3) sugar. Both cross effects and own effects are examined on typical policy targets. Results suggest that while world prices are sometimes drastically altered, the magnitude of cross effects is small and sometimes ambiguous compared to own effects. Feed livestock linkages are dominant factors in the economic rationale behind the interactions between countries. The case for cooperation in this trade game is, however, supported by the evidence from at least a budget point of view.Agricultural and Food Policy, International Relations/Trade,

Shadowing effects for continuum and discrete deposition models

We study the dynamical evolution of the deposition interface using both discrete and continuous models for which shadowing effects are important. We explain why continuous and discrete models implying both only shadowing deposition do not give the same result and propose a continuous model which allow to recover the result of the discrete one exhibiting a strong columnar morphology

A Lyra2 FPGA Core for Lyra2REv2-Based Cryptocurrencies

Lyra2REv2 is a hashing algorithm that consists of a chain of individual hashing algorithms and it is used as a proof-of-work function in several cryptocurrencies that aim to be ASIC-resistant. The most crucial hashing algorithm in the Lyra2REv2 chain is a specific instance of the general Lyra2 algorithm. In this work we present the first FPGA implementation of the aforementioned instance of Lyra2 and we explain how several properties of the algorithm can be exploited in order to optimize the design.Comment: 5 pages, to be presented at the IEEE International Symposium on Circuits and Systems (ISCAS) 201

A Standalone FPGA-based Miner for Lyra2REv2 Cryptocurrencies

Lyra2REv2 is a hashing algorithm that consists of a chain of individual hashing algorithms, and it is used as a proof-of-work function in several cryptocurrencies. The most crucial and exotic hashing algorithm in the Lyra2REv2 chain is a specific instance of the general Lyra2 algorithm. This work presents the first hardware implementation of the specific instance of Lyra2 that is used in Lyra2REv2. Several properties of the aforementioned algorithm are exploited in order to optimize the design. In addition, an FPGA-based hardware implementation of a standalone miner for Lyra2REv2 on a Xilinx Multi-Processor System on Chip is presented. The proposed Lyra2REv2 miner is shown to be significantly more energy efficient than both a GPU and a commercially available FPGA-based miner. Finally, we also explain how the simplified Lyra2 and Lyra2REv2 architectures can be modified with minimal effort to also support the recent Lyra2REv3 chained hashing algorithm.Comment: 13 pages, accepted for publication in IEEE Trans. Circuits Syst. I. arXiv admin note: substantial text overlap with arXiv:1807.0576

Determining species tree topologies from clade probabilities under the coalescent

One approach to estimating a species tree from a collection of gene trees is to first estimate probabilities of clades from the gene trees, and then to construct the species tree from the estimated clade probabilities. While a greedy consensus algorithm, which consecutively accepts the most probable clades compatible with previously accepted clades, can be used for this second stage, this method is known to be statistically inconsistent under the multispecies coalescent model. This raises the question of whether it is theoretically possible to reconstruct the species tree from known probabilities of clades on gene trees. We investigate clade probabilities arising from the multispecies coalescent model, with an eye toward identifying features of the species tree. Clades on gene trees with probability greater than 1/3 are shown to reflect clades on the species tree, while those with smaller probabilities may not. Linear invariants of clade probabilities are studied both computationally and theoretically, with certain linear invariants giving insight into the clade structure of the species tree. For species trees with generic edge lengths, these invariants can be used to identify the species tree topology. These theoretical results both confirm that clade probabilities contain full information on the species tree topology and suggest future directions of study for developing statistically consistent inference methods from clade frequencies on gene trees.Comment: 25 pages, 2 figure

Microfluidic breakups of confined droplets against a linear obstacle: The importance of the viscosity contrast.

International audienceCombining experiments and theory, we investigate the break-up dynamics of deformable objects, such as drops and bubbles, against a linear micro-obstacle. Our experiments bring the role of the viscosity contrast Δη between dispersed and continuous phases to light: the evolution of the critical capillary number to break a drop as a function of its size is either nonmonotonic (Δη>0) or monotonic (Δη≤0). In the case of positive viscosity contrasts, experiments and modeling reveal the existence of an unexpected critical object size for which the critical capillary number for breakup is minimum. Using simple physical arguments, we derive a model that well describes observations, provides diagrams mapping the four hydrodynamic regimes identified experimentally, and demonstrates that the critical size originating from confinement solely depends on geometrical parameters of the obstacle