4,881 research outputs found

    The Relationship between IR Effectiveness Measures and User Satisfaction

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    This paper presents an experimental study of users assessing the quality of Google web search results. In particular we look at how users' satisfaction correlates with the effectiveness of Google as quantified by IR measures such as precision and the suite of Cumulative Gain measures (CG, DCG, NDCG). Results indicate strong correlation between users' satisfaction, CG and precision, moderate correlation with DCG, with perhaps surprisingly negligible correlation with NDCG. The reasons for the low correlation with NDCG are examined

    Capital budgeting under relational contracting: optimal ranking and duration criteria for schemes of concession, project-financing and public-private partnership

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    Project-financing and public-private partnership schemes are joint projects of investment that are generally submitted to investment valuation criteria based on compound discounting. However, the theoretical basis of these criteria is at issue nowadays. According to recent studies on relational contracting economics and behavioral finance, joint projects of investment can be considered as special relational environments where the project's returns improve on alternative replacement opportunities. This article aims to bridge the gap between new theories and widespread valuation techniques by providing a generalised approach to investment valuation. This article suggests new valuation criteria that fit those theoretical developments, including an endogenous optimal duration that the project's contractual agreement may integrate.discounting; investment decision criteria; capital budgeting; project finance and public private partnerships; endogenous optimal duration; cost of capital for government

    Endogenous structural change and climate targets.

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    This paper envisages endogenous technical change as resulting from the interplay between the economic growth engine, consumption, technology and localization patterns. We perform numerical simulations with the recursive dynamic general equilibrium model IMACLIM-R to study how modeling induced technical change affects costs of CO2 stabilization. IMACLIM-R incorporates innovative specifications about final consumption of transportation and energy to represent critical stylized facts such as rebound effects and demand induction by infrastructures and equipments. Doing so brings to light how induced technical change may not only lower stabilization costs thanks to pure technological progress, but also triggers induction of final demand - effects critical to both the level of the carbon tax and the costs of policy given a specific stabilization target. Finally, we study the sensitivity of total stabilization costs to various parameters including both technical assumptions as accelerated turnover of equipments and non-energy choices as alternative infrastructure policies.induced technical change; structural change; climate policy; carbon tax;transportation; infrastructures

    Equity of Attention: Amortizing Individual Fairness in Rankings

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    Rankings of people and items are at the heart of selection-making, match-making, and recommender systems, ranging from employment sites to sharing economy platforms. As ranking positions influence the amount of attention the ranked subjects receive, biases in rankings can lead to unfair distribution of opportunities and resources, such as jobs or income. This paper proposes new measures and mechanisms to quantify and mitigate unfairness from a bias inherent to all rankings, namely, the position bias, which leads to disproportionately less attention being paid to low-ranked subjects. Our approach differs from recent fair ranking approaches in two important ways. First, existing works measure unfairness at the level of subject groups while our measures capture unfairness at the level of individual subjects, and as such subsume group unfairness. Second, as no single ranking can achieve individual attention fairness, we propose a novel mechanism that achieves amortized fairness, where attention accumulated across a series of rankings is proportional to accumulated relevance. We formulate the challenge of achieving amortized individual fairness subject to constraints on ranking quality as an online optimization problem and show that it can be solved as an integer linear program. Our experimental evaluation reveals that unfair attention distribution in rankings can be substantial, and demonstrates that our method can improve individual fairness while retaining high ranking quality.Comment: Accepted to SIGIR 201

    The benefits of cooperation under uncertainty: the case of climate change

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    This article presents an analysis of the behavior of countries defining their climate policies in an uncertain context. The analysis is made using the S-CWS model, a stochastic version of an integrated assessment growth model. The model includes a stochastic definition of the climate sensitivity parameter. We show that the impact of uncertainty on policy design critically depends on the shape of the damage function. We also examine the benefits of cooperation in the context of uncertainty: we highlight the existence of an additional benefit of cooperation, namely risk reduction.cooperation, uncertainty, climate change, integrated assessment model

    Modeling and Hedging Rain Risk

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    In this article we price a precipitation option based on empirical weather data from Germany using different pricing methods, among them Burn Analysis, Index Value Simulation and Daily Simulation. For that purpose we develop a daily precipitation model. Moreover, a de-correlation analysis is proposed to assess the spatial basis risk that is inherent to rainfall derivatives. The models are applied to precipitation data in Brandenburg, Germany. Based on simplifying assumptions of the production function, we quantify and compare the risk exposure of grain producers with and without rainfall insurance. It turns out that a considerable risk remains with producers who are remotely located from the weather station. Another finding is that significant differences may occur between the pricing methods. We identify the strengths and weaknesses of the pricing methods and give some recommendations for their applications. Our results are relevant for producers as well as for potential sellers of weather derivatives.Risk and Uncertainty,
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