101,942 research outputs found
Combinatorial benders' cuts for mixed-integer linear programming
No full textMixed-integer programs (MIPs) involving logical implications modeled through big-M coefficients are notoriously among the hardest to solve. In this paper, we propose and analyze computationally an automatic problem reformulation of quite general applicability, aimed at removing the model dependency on the big-M coefficients. Our solution scheme defines a master integer linear problem (ILP) with no continuous variables, which contains combinatorial information on the feasible integer variable combinations that can be “distilled” from the original MIP model. The master solutions are sent to a slave linear program (LP), which validates them and possibly returns combinatorial inequalities to be added to the current master ILP. The inequalities are associated to minimal (or irreducible) infeasible subsystems of a certain linear system, and can be separated efficiently in case the master solution is integer. The overall solution mechanism closely resembles the Benders’ one, but the cuts we produce are purely combinatorial and do not depend on the big-M values used in the MIP formulation. This produces an LP relaxation of the master problem which can be considerably tighter than the one associated with original MIP formulation. Computational results on two specific classes of hard-to-solve MIPs indicate that the new method produces a reformulation which can be solved some orders of magnitude faster than the original MIP model
La medicalizzazione della sessualità: un nuovo modo di concepire la femminilità e la maschilita
No full textPaesaggi fluviali, agricoltura e città: le strategie illustrate in due incontri a Torino
No full textTC trasporti&cultur
La gestione strategica del centro città: una proposta di metodo e un confronto tra esperienze internazionali
No full textHow can GIS support the evaluation and design of biodiverse agroecosystems and landscapes? Applying the Main Agroecological Structure to European agroecosystems
No full textAgrobiodiversity plays a critical role in fostering the stability, resilience, and sustainability of European farming systems. Nonetheless, there is currently a lack of comprehensive methods to describe its spatial distribution within farms, its connectivity with the surrounding landscape, and, most crucially, how the perceptions and actions of human communities affect it. The Main Agroecological Structure (MAS) has recently been proposed as an environmental index aiming to tackle such challenges by promoting a dialogue between landscape ecology and agroecology, encompassing criteria that focus on both landscape parameters and cultural variables. Geographic information systems (GIS) can play a key role in the measurement of the index by leveraging public geodata and engaging with the direct participation of communities to map the territories they inhabit and cultivate. Nevertheless, their use in this context has not yet been studied. We propose here a new GIS-based approach for estimating the Main Agroecological Structure: landscape criteria are assessed through the hybrid use of free and open-source GIS tools, field samplings, and participative mapping methods; cultural parameters are evaluated through semi-structured interviews. Contextually to the definition of such methodological foundations, the present study tests the relevance of the index to European agroecological contexts by applying the proposed workflow to three Italian farms characterized by different territorial and organizational forms. Along with a few modifications to the original proposal, we highlight the relevance of GIS in making agrobiodiversity visible at a landscape level within the context of the index. We also suggest some potential future applications related to local empowerment and agroecosystem mapping
(Free and Open) Satellite Imageries for Land Rights and Climate Justice in Amazon Agroforestry Systems
No full textMinistros de Economía, burocracia y política económica en el desarrollismo brasileño (1930-1964)
No full textSe aborda la existencia, entre los años 1930 y 1964, de un padrón de política económica desarrollista en Brasil, a pesar de la fuerte instabilidad política que caracterizó el período. El hilo conductor del análisis es institucionalista. Se intenta encontrar el locus institucional donde se producía la estabilidad de la política económica. Primeramente, revelamos que este no era el Ministerio de la Economía. A continuación, mostramos que los agentes de la burocracia económica son los responsables por mantener el padrón de política económica durante aquellos años. Los datos sobre ministros de Economía y sobre la burocracia económica fueron colectados a partir de fuentes diversas, pero especialmente del Dicionário Histórico Biográfico Brasileiro del CPDOC.Fil: Perissinotto, Renato. Universidad Federal de Parana. Curitiba. BrasilFil: Dantas, Eric G.. Universidad Federal de Parana. Curitiba. BrasilFil: Codato, Adriano. Universidad Federal de Parana. Curitiba. BrasilFil: Filipi, Thais M.. Universidad Federal de Parana. Curitiba. Brasi
The expropriation of Natural and Cultural Heritage of Plantationocene: limits of voluntary certification standards of palm oil industry in Ecuador
No full textThe actual climate emergency and crisis has posed a serious of significant challenges, one of which pertains to food-related issues, ranging from food security to the impact of the entire food supply chain. To emphasis the socio-environmental impact and the transformation of landscapes caused by the large-scale agro-industrial monoculture plantations, researchers have introduced the neologism Plantationocene. This term underscores how industrial agriculture operates as an extractive practice, displacing local communities, marginalizing smallholders, and exploiting both natural resources and labour. These issues are often addressed through the establishment of sustainability certifications by private governance entities. However, in practice, these certifications primarily serve as tools to obscure the socioenvironmental impacts of plantations from consumers, employing greenwashing practices and deceptive narratives. Additionally, they effectively usurp the role of state governments in land management and monitoring responsibilities. This paper is part of a research on the case of the Roundtable on Sustainable Palm Oil (RSPO), the most known certification scheme for oil palm. The RSPO has been expanding in Ecuador for approximately a decade and is associated with socio-environmental conflicts, including the case of the Barranquilla de San Javier community in the province of Esmeraldas. Furthermore, it examines the jurisdictional approach pilot project currently being implemented in the Ecuadorian Amazon
MOCVD growth and characterization of ZrO2 thin films obtained from unusual organo-zirconium precursors
No full textBibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
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