32 research outputs found

    Medieval Iceland, Greenland, and the New Human Condition: A case study in integrated environmental humanities

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    This paper contributes to recent studies exploring the longue durée of human impacts on island landscapes, the impacts of climate and other environmental changes on human communities, and the interaction of human societies and their environments at different spatial and temporal scales. In particular, the paper addresses Iceland during the medieval period (with a secondary, comparative focus on Norse Greenland) and discusses episodes where environmental and climatic changes have appeared to cross key thresholds for agricultural productivity. The paper draws upon international, interdisciplinary research in the North Atlantic region led by the North Atlantic Biocultural Organization (NABO) and the Nordic Network for Interdisciplinary Environmental Studies (NIES) in the Circumpolar Networks program of the Integrated History and Future of People on Earth (IHOPE). By interlinking analyses of historically grounded literature with archaeological studies and environmental science, valuable new perspectives can emerge on how these past societies may have understood and coped with such impacts. As climate and other environmental changes do not operate in isolation, vulnerabilities created by socioeconomic factors also beg consideration. The paper illustrates the benefits of an integrated environmental-studies approach that draws on data, methodologies and analytical tools of environmental humanities, social sciences, and geosciences to better understand long-term human ecodynamics and changing human-landscape-environment interactions through time. One key goal is to apply previously unused data and concerted expertise to illuminate human responses to past changes; a secondary aim is to consider how lessons derived from these cases may be applicable to environmental threats and socioecological risks in the future, especially as understood in light of the New Human Condition, the concept transposed from Hannah Arendt's influential framing of the human condition that is foregrounded in the present special issue. This conception admits human agency's role in altering the conditions for life on earth, in large measure negatively, while acknowledging the potential of this self-same agency, if effectively harnessed and properly directed, to sustain essential planetary conditions through a salutary transformation of human perception, understanding and remedial action. The paper concludes that more long-term historical analyses of cultures and environments need to be undertaken at various scales. Past cases do not offer perfect analogues for the future, but they can contribute to a better understanding of how resilience and vulnerability occur, as well as how they may be compromised or mitigated

    Robust tuning of a generalized predictor-based controller for integrating and unstable systems with long time-delay

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    In this work, a general structure to control long time-delay plants is proposed and an easy methodology to tune the control parameters is outlined. All the sensitivity transfer functions are delay free. The proposed scheme is equivalent to the Smith predictor but able to cope with any kind of systems, including nonminimum phase, unstable and integrating plants. The controllers are designed based on the delay free model. Contrary to other approaches, other than for the digital implementation, no delay approximation is used. A tuning parameter is provided in order to reach an intuitive tradeoff between performance and robust stability. A comparative analysis with respect to recently successful proposals shows a substantial improvement in the performance/robustness tradeoff as well as in the tuning process.This work has been partially granted by the Spanish Ministry of Education research Grants DPI2011-28507-C02-01 and PAID-06-12. The authors are also grateful to the Associate Editor and anonymous reviewers for their valuable feedback and comments.García Gil, PJ.; Albertos Pérez, P. (2013). Robust tuning of a generalized predictor-based controller for integrating and unstable systems with long time-delay. Journal of Process Control. 23(8):1205-1216. https://doi.org/10.1016/j.jprocont.2013.07.008S1205121623

    A critique of neo-mercantilist analyses of Icelandic political economy and crisis

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    Iceland’s journey from rags to riches in the 20th century is related, in the dominant discourse, to its gaining independence in 1944. This discourse played a significant role in both the legitimation of the finance-dominated growth model in the 1990s and 2000s and in the latter’s defence as it came under scrutiny before its collapse in October 2008. It is therefore ironic – or perhaps, in some sense, logical – to find dominant analyses of the crisis arising from the neo-mercantilist tradition. Drawing on Marxist critiques of neo-mercantilism, we challenge these interventions and thus seek to redress the neglect of social struggle in the dominant discourse

    Robustness of a discrete-time predictor-based controller for time-varying measurement delay

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    A predictor-based controller for time-varying delay systems is presented in this paper and its robustness properties for different uncertainties are analyzed. First, a time-varying delay dependent stability condition is expressed in terms of LMIs. Then, uncertainties in the knowledge of all plant-model parameters are considered and the resulting closed-loop system is shown to be robust with respect to these uncertainties. A significant improvement with respect to the same control strategy without predictor is achieved. The scheme is applicable to open-loop unstable plants and it has been tested in a real-time application to control the roll angle of a quad-rotor helicopter prototype. The experimental results show good performance and robustness of the proposed scheme even in the presence of long delay uncertainties. © 2011 Elsevier Ltd.This work has been partially granted by Conselleria de Educacion under PROMETEO project number 2008-088, and CICYT no. DPI2008-06737-C02-01 from Spanish government.Gonzalez, A.; García Gil, PJ.; Albertos Pérez, P.; Castillo, P.; Lozano, R. (2012). Robustness of a discrete-time predictor-based controller for time-varying measurement delay. Control Engineering Practice. 20(2):102-110. https://doi.org/10.1016/j.conengprac.2011.09.001S10211020

    A critical review of smaller state diplomacy

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    In The Peloponnesian War, Thucydides (1972: 402) highlights the effects of the general, overall weakness of smaller states vis-à-vis larger, more powerful ones in a key passage, where the Athenians remind the Melians that: “… since you know as well as we do that, as the world goes, right is only in question between equals in power. Meanwhile, the strong do what they can and the weak suffer what they must.” Concerns about the vulnerability of small, weak, isolated states have echoed throughout history: from Thucydides, through the review by Machiavelli (1985) of the risks of inviting great powers to intervene in domestic affairs, through 20th century US-led contemporary political science (Vital, 1971; Handel, 1990) and Commonwealth led scholarship (Commonwealth Secretariat, 1985). In the context of 20th century ‘Balkanization’, the small state could also prove unstable, even hostile and uncooperative, a situation tempting enough to invite the intrusion of more powerful neighbours: a combination, according to Brzezinski (1997: 123-124) of a power vacuum and a corollary power suction2: in the outcome, if the small state is ‘absorbed’, it would be its fault, and its destiny, in the grand scheme of things. In an excellent review of small states in the context of the global politics of development, Payne (2004: 623, 634) concludes that “vulnerabilities rather than opportunities are the most striking consequence of smallness”. It has been recently claimed that, since they cannot defend or represent themselves adequately, small states “lack real independence, which makes them suboptimal participants in the international system” (Hagalin, 2005: 1). There is however, a less notable and acknowledged but more extraordinary strand of argumentation that considers ‘the power of powerlessness’, and the ability of small states to exploit their smaller size in a variety of ways in order to achieve their intended, even if unlikely, policy outcomes. The pursuance of smaller state goals becomes paradoxically acceptable and achievable precisely because such smaller states do not have the power to leverage disputants or pursue their own agenda. A case in point concerns the smallest state of all, the Vatican, whose powers are both unique and ambiguous, but certainly not insignificant (The Economist, 2007). Smaller states have “punched above their weight” (e.g. Edis, 1991); and, intermittently, political scientists confront their “amazing intractability” (e.g. Suhrke, 1973: 508). Henry Kissinger (1982: 172) referred to this stance, with obvious contempt, as “the tyranny of the weak”3. This paper seeks a safe passage through these two, equally reductionist, propositions. It deliberately focuses first on a comparative case analysis of two, distinct ‘small state-big state’ contests drawn from the 1970s, seeking to infer and tease out the conditions that enable smaller ‘Lilliputian’ states (whether often or rarely) to beat their respective Goliaths. The discussion is then taken forward to examine whether similar tactics can work in relation to contemporary concerns with environmental vulnerability, with a focus on two other, small island states. Before that, the semiotics of ‘the small state’ need to be explored, since they are suggestive of the perceptions and expectations that are harboured by decision makers at home and abroad and which tend towards the self-fulfilling prophecy.peer-reviewe

    Model-Based Detection of Hydrogen Leaks in a Fuel Cell Stack

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    Identification of Dead-time Processes

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