28,771 research outputs found

    Shift factor-based SCOPF topology control MIP formulations with substation configurations

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    Topology control (TC) is an effective tool for managing congestion, contingency events, and overload control. The majority of TC research has focused on line and transformer switching. Substation reconfiguration is an additional TC action, which consists of opening or closing breakers not in series with lines or transformers. Some reconfiguration actions can be simpler to implement than branch opening, seen as a less invasive action. This paper introduces two formulations that incorporate substation reconfiguration with branch opening in a unified TC framework. The first method starts from a topology with all candidate breakers open, and breaker closing is emulated and optimized using virtual transactions. The second method takes the opposite approach, starting from a fully closed topology and optimizing breaker openings. We provide a theoretical framework for both methods and formulate security-constrained shift factor MIP TC formulations that incorporate both breaker and branch switching. By maintaining the shift factor formulation, we take advantage of its compactness, especially in the context of contingency constraints, and by focusing on reconfiguring substations, we hope to provide system operators additional flexibility in their TC decision processes. Simulation results on a subarea of PJM illustrate the application of the two formulations to realistic systems.The work was supported in part by the Advanced Research Projects Agency-Energy, U.S. Department of Energy, under Grant DE-AR0000223 and in part by the U.S. National Science Foundation Emerging Frontiers in Research and Innovation under Grant 1038230. Paper no. TPWRS-01497-2015. (DE-AR0000223 - Advanced Research Projects Agency-Energy, U.S. Department of Energy; 1038230 - U.S. National Science Foundation Emerging Frontiers in Research and Innovation)http://buprimo.hosted.exlibrisgroup.com/primo_library/libweb/action/openurl?date=2017&issue=2&isSerivcesPage=true&spage=1179&dscnt=2&url_ctx_fmt=null&vid=BU&volume=32&institution=bosu&issn=0885-8950&id=doi:10.1109/TPWRS.2016.2574324&dstmp=1522778516872&fromLogin=truePublished versio

    The MacArthur Foundation in Nigeria: Report on Activities 2009

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    Highlights the foundation's work to build the scientific research capacity of Nigerian universities, to reduce maternal mortality and improve sexual and reproductive health, and to advance human rights. Includes grantee profiles and selected grants list

    Formal verification of a software countermeasure against instruction skip attacks

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    Fault attacks against embedded circuits enabled to define many new attack paths against secure circuits. Every attack path relies on a specific fault model which defines the type of faults that the attacker can perform. On embedded processors, a fault model consisting in an assembly instruction skip can be very useful for an attacker and has been obtained by using several fault injection means. To avoid this threat, some countermeasure schemes which rely on temporal redundancy have been proposed. Nevertheless, double fault injection in a long enough time interval is practical and can bypass those countermeasure schemes. Some fine-grained countermeasure schemes have also been proposed for specific instructions. However, to the best of our knowledge, no approach that enables to secure a generic assembly program in order to make it fault-tolerant to instruction skip attacks has been formally proven yet. In this paper, we provide a fault-tolerant replacement sequence for almost all the instructions of the Thumb-2 instruction set and provide a formal verification for this fault tolerance. This simple transformation enables to add a reasonably good security level to an embedded program and makes practical fault injection attacks much harder to achieve

    Dietary contribution of wild edible plants to women's diets in the buffer zone around the Lama forest, Benin : an underutilized potential

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    Rural populations in developing countries face food insecurity and malnutrition despite being surrounded by extraordinary biodiversity. The international community increasingly recognizes the role of agro-biodiversity and Wild Edible Plants (WEPs) in their contributions to managing risk and building resilience and sustainable food systems. Studies on real contributions of WEPs to peoples’ diets, however, are uncommon. This study assessed the contribution ofWEPs to diets of women living in the buffer zone of the Lama forest in southern Benin. During the long dry season, a cross-sectional survey was carried out on 120 women, covering their knowledge and attitudes towards WEPs and two non-consecutive 24-h recalls of their WEP consumption. Contribution ofWEPs to total dietary intake was low due to infrequent use and small portion sizes. The highest nutrient contributions of WEPs measured were for copper (13.9 %) and iron (4.6%) but the majority of the women had intake values below the Estimated Average Requirements (EARs) for these elements - copper 65 % and iron 91 % Women’s dietary diversity was significantly higher among WEP consumers than non-consumers, mainly due to higher consumption of dark green leafy vegetables. WEPs were less consumed as a replacement for other foods but rather as a complement to the diet. The study population generally appreciated WEPs, while some constraints were reported regarding preparation, conservation and commercialization. Before widely promoting WEP consumption in order to exploit their dietary potential, additional investigations are needed into their nutrient composition, cultural and market value, their sustainable harvest levels and possible integration into innovative farming systems

    The MacArthur Foundation in Nigeria: Report on Activities 2006

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    Contains president's message, foundation information, information on focus areas and programs in Nigeria, grantee profiles, lists of recent grants, and lists of board members and staff

    Dietary contribution of wild edible plants to women's diets in the buffer zone around the Lama forest, Benin - an underutilized potential

    Get PDF
    Rural populations in developing countries face food insecurity and malnutrition despite being surrounded by extraordinary biodiversity. The international community increasingly recognizes the role of agro-biodiversity and Wild Edible Plants (WEPs) in their contributions to managing risk and building resilience and sustainable food systems. Studies on real contributions of WEPs to peoples’ diets, however, are uncommon. This study assessed the contribution of WEPs to diets of women living in the buffer zone of the Lama forest in southern Benin. During the long dry season, a cross-sectional survey was carried out on 120 women, covering their knowledge and attitudes towards WEPs and two non-consecutive 24-h recalls of their WEP consumption. Contribution of WEPs to total dietary intake was low due to infrequent use and small portion sizes. The highest nutrient contributions of WEPs measured were for copper (13.9 %) and iron (4.6 %) but the majority of the women had intake values below the Estimated Average Requirements (EARs) for these elements - copper 65 % and iron 91 % Women’s dietary diversity was significantly higher among WEP consumers than non-consumers, mainly due to higher consumption of dark green leafy vegetables. WEPs were less consumed as a replacement for other foods but rather as a complement to the diet. The study population generally appreciated WEPs, while some constraints were reported regarding preparation, conservation and commercialization. Before widely promoting WEP consumption in order to exploit their dietary potential, additional investigations are needed into their nutrient composition, cultural and market value, their sustainable harvest levels and possible integration into innovative farming systems

    Taxation of gains from banking and insurance businesses in New Zealand

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    There has been major contest over the taxation of business income. Questions are twofold: the factual one of defining the boundaries of the business activity. Second, that of determining whether a particular gain comes within the ambit of ‘business’. Recent NZ cases have sought to apply the guiding principle - that it is not the size of the gain but the source of it that determines the taxation consequences. Logically, this principle should apply to specialist businesses such as those dealing with banking and insurance. However, the NZ Commissioner has, until 10 years ago, argued that it is the size rather than the source of the gain that is the determining criterion. And since the questions of what is the scope of the particular business activity and whether the particular gain has arisen in the course of such activity are purely factual ones, they are to be guided by the facts of each case. This article concludes that the decisions are indeed based on their particular facts. Further, it investigates how important it is for the taxpayer to ponder the strategy that is to underpin the particular business. The evidence of such strategy being in place and having the practical effect of guiding the decision making of the taxpayer company’s business activities are highly significant in determining the taxation consequences of such decision making. The consistency with which such corporate strategy or policy is formulated and implemented tends to determine their taxation consequences
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