Incremental Skip-gram Model with Negative Sampling

This paper explores an incremental training strategy for the skip-gram model with negative sampling (SGNS) from both empirical and theoretical perspectives. Existing methods of neural word embeddings, including SGNS, are multi-pass algorithms and thus cannot perform incremental model update. To address this problem, we present a simple incremental extension of SGNS and provide a thorough theoretical analysis to demonstrate its validity. Empirical experiments demonstrated the correctness of the theoretical analysis as well as the practical usefulness of the incremental algorithm

REDD – potential environmental justice challenges and the way forward

The use of market-based mechanisms is transforming the way nature and ecosystems are managed with profound implications on environmental governance. The rapid growth of the carbon market appears to have significant environmental justice implications because of the way costs and benefits are distributed among different actors. In particular, potentially conflicting uses of forest, one as carbon sink for generating credit and the other for subsistence of local and indigenous populations, suggests enormous environmental justice implications of REDD (Reducing Emissions from Deforestation and forest Degradation). Despite being in a pilot stage, REDD is already transforming the way forest is managed with significant impacts on many forest-dependent communities in developing countries. The paper uses the Six Moments Framework proposed by David Harvey to assess the process whereby different stakeholders respond to changes triggered by the introduction of REDD. Each moment, namely: discourse; power; values and beliefs; social relations; material practices; and institutions and rituals, influences each other and its interaction shapes the scope and direction of social changes. As Harvey recognises, interactions often favour those in power through, for example, political elite advocating market-based mechanisms to address environmental problems and building a REDD framework based on their interests. However, the paper argues that careful analysis of forces at work within and across moment could help identify potential entry points from where a challenge to such processes can be launched. Such analysis would help open up greater space for weaker groups and pave the way forward for a more equitable and sustainable forest management. The paper assesses the process of designing and refining the REDD framework in South East Asia through the Six Moments Framework with a discussion on the potential entry points in empirical settings.final draf

Black hole perturbation in the most general scalar-tensor theory with second-order field equations I: The odd-parity sector

We perform a fully relativistic analysis of odd-type linear perturbations around a static and spherically symmetric solution in the most general scalar-tensor theory with second-order field equations in four-dimensional spacetime. It is shown that, as in the case of general relativity, the quadratic action for the perturbations reduces to the one having only a single dynamical variable, from which concise formulas for no-ghost and no-gradient instability conditions are derived. Our result is applicable to all the theories of gravity with an extra scalar degree of freedom. We demonstrate how the generic formulas can be applied to some particular examples such as the Brans-Dicke theory, $f(R)$ models, and Galileon gravity.Comment: 10 pages; v2. matches the published version in Phys. Rev. D; v3. typos in Eqs. (A1), (A3)--(A5) fixed, results unchanged; v4. a typo in Eq. (24) fixed, results unchanged; v5. a typo in Eq. (14) fixed, results unchange

Two-photon interference of multimode two-photon pairs with an unbalanced interferometer

Two-photon interference of multimode two-photon pairs produced by an optical parametric oscillator has been observed for the first time with an unbalanced interferometer. The time correlation between the multimode two photons has a multi-peaked structure. This property of the multimode two-photon state induces two-photon interference depending on delay time. The nonclassicality of this interference is also discussed.Comment: 5 pages, 4 figure