Multimodal Visual Concept Learning with Weakly Supervised Techniques

Despite the availability of a huge amount of video data accompanied by descriptive texts, it is not always easy to exploit the information contained in natural language in order to automatically recognize video concepts. Towards this goal, in this paper we use textual cues as means of supervision, introducing two weakly supervised techniques that extend the Multiple Instance Learning (MIL) framework: the Fuzzy Sets Multiple Instance Learning (FSMIL) and the Probabilistic Labels Multiple Instance Learning (PLMIL). The former encodes the spatio-temporal imprecision of the linguistic descriptions with Fuzzy Sets, while the latter models different interpretations of each description's semantics with Probabilistic Labels, both formulated through a convex optimization algorithm. In addition, we provide a novel technique to extract weak labels in the presence of complex semantics, that consists of semantic similarity computations. We evaluate our methods on two distinct problems, namely face and action recognition, in the challenging and realistic setting of movies accompanied by their screenplays, contained in the COGNIMUSE database. We show that, on both tasks, our method considerably outperforms a state-of-the-art weakly supervised approach, as well as other baselines.Comment: CVPR 201

Quantum Zeno Effect in the Decoherent Histories

The quantum Zeno effect arises due to frequent observation. That implies the existence of some experimenter and its interaction with the system. In this contribution, we examine what happens for a closed system if one considers a quantum Zeno type of question, namely: "what is the probability of a system, remaining always in a particular subspace". This has implications to the arrival time problem that is also discussed. We employ the decoherent histories approach to quantum theory, as this is the better developed formulation of closed system quantum mechanics, and in particular, dealing with questions that involve time in a non-trivial way. We get a very restrictive decoherence condition, that implies that even if we do introduce an environment, there will be very few cases that we can assign probabilities to these histories, but in those cases, the quantum Zeno effect is still present.Comment: 7 pages, To appear in DICE 2006 (Decoherence Information Complexity and Entropy) conference proceeding

Fiscal multipliers in Ireland using FIR-GEM model. ESRI WP636, September 2019

This article employs the newly developed FIR-GEM model to compute fiscal multipliers in Ireland for the main tax-spending policy instruments, namely government consumption, public investment, public wages, public transfers, consumption, capital and labour taxes. We focus on the short run fiscal multipliers as a measure to evaluate the effect of a temporary fiscal stimulus policy over three years. We find that the size of output multipliers crucially depends on the openness of the Irish economy and the method of fiscal financing employed. Our main results indicate that spending increases or tax cuts increase Irish GDP but Irish fiscal multipliers are relatively smaller in magnitude due to the openness of the economy. That is the increase in aggregate output is partly offset due to the negative effect of a fiscal stimulus in the Irish external balance. A fiscal expansion via spending increases or tax cuts results in a compositional change in aggregate Irish output. The positive effects on aggregate output come mostly from the stimulative effects induced in the non-tradable sector while the tradable sector remains unaffected or reduces in size. A fiscal stimulus is likely to crowd out exports and crowd in imports; this results in a deterioration in Irish trade balance. Magnitude-wise short run spending multipliers are consistently higher than short run tax multipliers. The highest fiscal multiplier effect is as a result of spending on public investment and government consumption. A fiscal stimulus via spending and consumption tax cuts have a higher effect on impact but can put upward pressures on domestic prices vis-à-vis the rest of the world and lead to a deterioration in Irish international competitiveness in the longer run. A fiscal stimulus via income tax cuts take more time to materialize and has a smaller effect on impact but the stimulus can reduce production costs and prices. This improves the international competitiveness of the Irish economy and has a more positive effect over the longer-term

Book review: media regulation: governance and the interests of citizens and consumers by Peter Lunt and Sonia Livingstone

In Media Regulation, Peter Lunt and Sonia Livingstone examine the challenges of regulation in the global mediated sphere. The book explores the way that regulation affects the relations between government, the media and communications market, civil society, citizens and consumers. Dr Petros Iosifidis finds that the book’s elegant but rigorous analysis and use of case studies from all over the world make it an essential tool for undergraduate and graduate students in the field of media and communications

Quantum Zeno Effect in the Decoherent Histories

The quantum Zeno effect arises due to frequent observation. That implies the existence of some experimenter and its interaction with the system. In this contribution, we examine what happens for a closed system if one considers a quantum Zeno type of question, namely: "what is the probability of a system, remaining always in a particular subspace". This has implications to the arrival time problem that is also discussed. We employ the decoherent histories approach to quantum theory, as this is the better developed formulation of closed system quantum mechanics, and in particular, dealing with questions that involve time in a non-trivial way. We get a very restrictive decoherence condition, that implies that even if we do introduce an environment, there will be very few cases that we can assign probabilities to these histories, but in those cases, the quantum Zeno effect is still present.Comment: 7 pages, To appear in DICE 2006 (Decoherence Information Complexity and Entropy) conference proceeding