1,721,119 research outputs found
Dynamic immigration control improving inverse old-age dependency ratio in a pay-as-you-go pension system
No full textThe sustainability of pay-as-you-go pension systems is a major concern in most European countries. Considering the inverse old-age dependency ratio (the proportion of the class of actives to pensioners) as a sustainability index, based on a classical demographic model, a new optimal control model is proposed where the sustainability index grows along a prescribed trajectory, minimizing the annual immigration flow over a given time horizon. In addition to the admission of young immigrants, immigrant females, by having higher birth rates than the residents, can substantially improve the sustainability index. For the efficiency of the immigration policy, the admission of immigrants is also differentiated by age. Within the limits of our model, the social cost of sustainability in terms of immigration can be estimated on beforehand. Therefore, the simulation analysis of our model may give a sound foundation to the corresponding decision of policy makers. © 2014 Elsevier B.V
Demographic Dynamics for the pay-as-you-go pension system
No full textThe present study focuses on certains problems of pay-as-you-go pension systems. In particular, based on reproduction and survival rates, a Leslie type model is used for the analysis of the demographic dynamics of a population. The presented model is different from the classical Leslie model, since it considers a population divided into sexes, implying that the system matrix does not satisfy the irreducibility and primitivity conditions used in the Perron-Frobenius theory. Applying this theory to a submatrix corresponding to a subpopulation of females, the existence of an asymptotic age distribution in proved and then extended to the whole population. The obtained result is applied to the Italian population, providing projections on its demographic evolution. In the paper the impact of asymptotic demographic equilibrium on the pay-as-you-go pension system, in terms of financial sustainability, is also studied
Modelling a possible change in the Italian pay-as-you-go pension system.
No full textThe aim of our paper is to compare the adequacy of the pension system in force (Fornero's law) with the proposal presented by Giuliano Cazzola e Tiziano Treu. To assess the adequacy we compare the population averaged replacement rates (i.e. the ratio between the monthly pension and the last wage perceived by the worker) emerging under the two systems.
We make use of a mathematical model which, under the hypothesis of demographic equilibrium, formalizes the legislative changes of the pay-as-you-go pension system
Sustainability of a pay-as-you-go pension system by dynamic immigration control
No full textThe sustainability of a pay-as-you-go pension system strongly depends on the underlying demographic process determining the inverse old-age dependency ratio (the proportion of the active subpopulation to pensioners), considered as a sustainability index. Based on the classical Leslie population model, a dynamic demographic model including a controlled immigration is set up. A convergent algorithm is given which steers the population towards a demographic equilibrium with a better sustainability index, and at the same time minimizes the yearly immigration. In addition, simulations are provided for Italian data, comparing the demographic dynamics corresponding to different decision scenarios. (C) 2012 Elsevier Inc. All rights reserved
A comparison of two legislative approaches to the pay-as-you-go pension system in terms of adequacy. The Italian case
No full textThe aim of our work is to evaluate a new legislative proposal of the Italian pension system due to Giuliano Cazzola e Tiziano Treu and to compare it with the system in force due to former Minister Elsa Fornero. The evaluation is made in terms of adequacy. We make use of a mathematical model which, under the hypothesis of demographic equilibrium, formalizes the legislative changes of the pay-as-you-go pension system. The model is tested using Italian demographic and socio-economic data. The pay-as-you-go pension system in force is notional defined contribution and has the huge drawback that the replacement rate (the ratio between the monthly pension and the last wage perceived by the worker) is very low. We compare the two pension systems evaluating the dynamics of the replacement rate
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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