21,413 research outputs found
On Multi-Relational Link Prediction with Bilinear Models
We study bilinear embedding models for the task of multi-relational link
prediction and knowledge graph completion. Bilinear models belong to the most
basic models for this task, they are comparably efficient to train and use, and
they can provide good prediction performance. The main goal of this paper is to
explore the expressiveness of and the connections between various bilinear
models proposed in the literature. In particular, a substantial number of
models can be represented as bilinear models with certain additional
constraints enforced on the embeddings. We explore whether or not these
constraints lead to universal models, which can in principle represent every
set of relations, and whether or not there are subsumption relationships
between various models. We report results of an independent experimental study
that evaluates recent bilinear models in a common experimental setup. Finally,
we provide evidence that relation-level ensembles of multiple bilinear models
can achieve state-of-the art prediction performance
Choosing international organizations: when do states and the World Bank collaborate on environmental projects?
While international cooperation research emphasizes institutional design,
states mostly interact with existing organizations. How do states choose organizations
for cooperation? We develop a theory of agency choice for development projects,
emphasizing the importance of domestic institutions, the scope of cooperation, and
the resources of the implementing agency. If states are to cooperate with funding
agencies that have abundant resources, such as the World Bank, they must accept
more stringent conditions on project implementation. We argue states accept the
stringent conditions that resourceful organizations demand if the public goods from
project implementation are highly valuable. Empirically, this is the case for democratic
states, large projects, and projects that produce national instead of global public
goods. We test this theory using data on 2,882 Global Environment Facility (GEF)
projects, 1991–2011. The GEF offers an ideal case because various implementing
agencies are responsible for the actual projects. States implement projects in collaboration
with the World Bank, which has the most expertise and resources among
the GEF’s implementing agencies, if their regime type is democracy, the project size
is large, and the benefits are primarily national. Qualitative evidence sheds light on
causal mechanisms
The Riesz representation theorem and weak compactness of semimartingales
We show that the sequential closure of a family of probability measures on
the canonical space of c{\`a}dl{\`a}g paths satisfying Stricker's uniform
tightness condition is a weak compact set of semimartingale measures in
the pairing of the Riesz representation theorem under topological assumptions
on the path space. Similar results are obtained for quasi- and supermartingales
under analogous conditions. In particular, we give a full characterization of
the strongest topology on the Skorokhod space for which these results are true.Comment: V1-V6 differ substantially from v7-v8 in exposition v9 adds lemma
3.5, example 3.9, remark 5.6, proposition 5.7 (i) and some other minor
remark
Understanding environmental policy preferences: new evidence from Brazil
We examine the relationship between socio-economic factors and public opinion on environmental policies in Brazil, drawing on a survey conducted in June 2012. There are few systematic studies of the determinants of environmental preferences in emerging economies, and Brazil is a particularly interesting case because of its democratic political system, rapid economic growth, and importance for the global environment. In general, we find that the Brazilian public is highly supportive of environmental protection. To explain variation in environmental preferences, we focus on the effects of income and education. Many previous studies suggest that both should have positive effects, but the empirical evidence is mixed. Indeed, we find that income has no effect on environmental preferences. However, education is a strong predictor of environmental preferences. While college education is not necessary for environmental awareness, there is a large difference between Brazilians with primary and secondary education. For policy, the findings imply that investment in secondary education can raise environmental awareness, regardless of income levels
Pathwise super-replication via Vovk's outer measure
Since Hobson's seminal paper [D. Hobson: Robust hedging of the lookback
option. In: Finance Stoch. (1998)] the connection between model-independent
pricing and the Skorokhod embedding problem has been a driving force in robust
finance. We establish a general pricing-hedging duality for financial
derivatives which are susceptible to the Skorokhod approach.
Using Vovk's approach to mathematical finance we derive a model-independent
super-replication theorem in continuous time, given information on finitely
many marginals. Our result covers a broad range of exotic derivatives,
including lookback options, discretely monitored Asian options, and options on
realized variance.Comment: 18 page
Linked Data - the story so far
The term “Linked Data” refers to a set of best practices for publishing and connecting structured data on the Web. These best practices have been adopted by an increasing number of data providers over the last three years, leading to the creation of a global data space containing billions of assertions— the Web of Data. In this article, the authors present the concept and technical principles of Linked Data, and situate these within the broader context of related technological developments. They describe progress to date in publishing Linked Data on the Web, review applications that have been developed to exploit the Web of Data, and map out a research agenda for the Linked Data community as it moves forward
Small and beautiful? The programme of activities and the least developed countries
Most carbon abatement projects under the Kyoto Protocol's Clean Development Mechanism (CDM) have been implemented in rapidly industrializing countries, notably China and India. To support small carbon abatement projects and to promote decarbonization in the least developed countries, the Programme of Activities (PoA) modality was introduced. Are the determinants of project implementation different under the PoA from those of conventional CDM projects? To answer this question, we conduct a statistical analysis of the global distribution of CDM projects and PoAs during the years 2007–2012. In regard to country size, large countries clearly dominate both the CDM and PoA, suggesting that the PoA may do only little to facilitate project implementation in small countries. However, the number of PoAs has a strong negative association with a country's corruption level, while the importance of corruption for the CDM is much smaller. Moreover, per capita income has no effect on PoA implementation, while high wealth levels have a weak positive effect on CDM projects. Thus, the PoA modality seems to promote sustainable development in poor countries that have exceeded a certain threshold of good governance. In this regard, PoAs are directing carbon credits to new areas, as many had initially hoped
Banks without Parachutes - Competitive Effects of Government Bail-out Policies
Lecture on the first SFB/TR 15 meeting, Gummersbach, July, 18 - 20, 2004The explicit or implicit protection of banks through government bail-out policies is a universal phenomenon. We analyze the competitive effects of such policies in two models with different degrees of transparency in the banking sector. Our main result is that the bail-out policy unambiguously leads to higher risk-taking at those banks that do not enjoy a bail-out guarantee. The reason is that the prospect of a bail-out induces the rotected bank to expand, thereby intensifying competition in the deposit market and depressing other banks’ margins. In contrast, the effects on the protected bank’s risk taking and on welfare depend on the transparency of the banking sector
Early transitions and tertiary enrolment: The cumulative impact of primary and secondary effects on entering university in Germany
Our aim is to assess how the number of working class students entering German universities can effectively be increased. Therefore, we estimate the proportion of students from the working class that would successfully enter university if certain policy interventions were in place to eliminate primary effects (performance differentials between social classes) and/or secondary effects (choice differentials net of performance) at different transition points. We extend previous research by analysing the sequence of transitions between elementary school enrolment and university enrolment and by accounting for the impact that manipulations at earlier transitions have on the performance distribution and size of the student ‘risk-set’ at subsequent transitions. To this end, we develop a novel simulation procedure which also seeks to find viable solutions to the shortcomings in the German data landscape. Our findings show that interventions are most effective if they take place early in the educational career. Neutralizing secondary effects at the transition to upper secondary school proves to be the single most effective means to increase participation rates in tertiary education among working class students. However, this comes at the expense of lower average performance levels. (DIPF/author
The Curse of Knowledge in Economic Settings: An Experimental Analysis
In economic analyses of asymmetric information, better-informed agents are assumed capable of reproducing the judgments of less-informed agents. We discuss a systematic violation of this assumption that we call the "curse of knowledge." Better-informed agents are unable to ignore private information even when it is in their interest to do so; more information is not always better. Comparing judgments made in individual-level and market experiments, we find that market forces reduce the curse by approximately 50 percent but do not eliminate it. Implications for bargaining, strategic behavior by firms, principal-agent problems, and choice under un-certainty are discussed
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