1,721,247 research outputs found
Optimal investment with vintage capital:Equilibrium distributions
Full text linkThe paper concerns the study of equilibrium points, or steady states, of economic systems arising in modeling optimal investment with vintage capital, namely, systems where all key variables (capitals, investments, prices) are indexed not only by time but also by age. Capital accumulation is hence described as a partial differential equation (briefly, PDE), and equilibrium points are in fact equilibrium distributions in the variable of ages. A general method is developed to compute and study equilibrium points of a wide range of infinite dimensional, infinite horizon, optimal control problems. We apply the method to optimal investment with vintage capital, for a variety of data, deriving existence and uniqueness of equilibrium distribution, as well as analytic formulas for optimal controls and trajectories in the long run. The examples suggest that the same method can be applied to other economic problems displaying heterogeneity. This shows how effective the theoretical machinery of optimal control in infinite dimension is in computing explicitly equilibrium distributions. To this extent, the results of this work constitute a first crucial step towards a thorough understanding of the behavior of optimal paths in the long run
Mothballing in a Duopoly: Evidence from a (Shale) Oil Market
Full text linkThe mothballing option has been studied in the literature, but mainly in decision theoretic frameworks. This paper looks at it from a strategic point of view and applies it to an incumbent-entrant framework. In particular, based on the recent strategic interactions between OPEC and the shale oil industry, we conduct a case study where the incumbent OPEC is a exible producer that competes with a representative shale oil firm. Upon entry, the latter produces a fixed amount but it can apply the mothballing option in times of low demand. Our main results are threefold. First, we find that under low demand uncertainty, the mothballing option has a negative effect on the value of the entrant. Second, a large market share of the entrant will stimulate mothballing, caused by a so-called squeeze strategy of the incumbent. Third, our empirical analysis of the (shale) oil market learns that a higher demand elasticity induces mothballing
Brown price and green firms:An ETS price floor for a clean transition?
Full text linkWe examine the optimal behavior of carbon-emitting companies operating under the European Union Emission Trading System (EU ETS), under which firms are obliged to purchase emission permits on the secondary market if their emissions exceed their allowance. Specifically, we consider the scenario where firms are endowed with the (real) option to undertake a “green” investment to cut their emissions and, thus, permit expenditures. The central challenge is the determination of the optimal time for investment within a stochastic framework characterized by uncertainty in EU ETS permit prices. We address the problem for a heterogeneous group of companies with diverse technological capabilities across industrial sectors. Furthermore, we incorporate a price floor for permit prices to mirror policy efforts aimed at promoting green transition by elevating emission costs. We solve this problem analytically and through numerical simulations calibrated to real market data. In addition to offering insights into individual firm behavior, our findings can support regulators in refining environmental policies, particularly regarding the role of permits price floor and its potential to expedite the green transition
Green electricity investments: Environmental target and the optimal subsidy
No full textBigerna S, Wen X, Hagspiel V, Kort PM. Green electricity investments: Environmental target and the optimal subsidy. European Journal of Operational Research. 2019;279(2):635-644.We investigate the optimal investment decision in renewables under market demand uncertainty, in the context of the Italian strategy for renewable deployment under the EU policy. The firm has to decide about the time and size of the investment. We find that a higher subsidy level induces the firm to invest earlier with a smaller investment capacity. This implies that a given environmental target cannot be reached by a too high (too low) subsidy level since this will cause the investment level to be too low (too late). We show that there exists an optimal (intermediate) subsidy level. Due to uncertain demand, in some cases ensuring to reach the environmental target in time requires an additional (conditional) subsidy. We propose a heuristic for policy makers stating when and how much subsidy to provide. Furthermore, we find that in a more uncertain economic environment the subsidy adjustment to maintain the target level of investment results in the firm investing earlier, which is opposite to the standard real options result. (C) 2019 Elsevier B.V. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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