214 research outputs found

    Limiting Ramp Rate of Wind Power Output using a Battery Based on the Variance Gamma Process

    Get PDF
    Abstract. A battery system is designed to reduce violations of ramping limit due to severe and long ramps of wind power output. The power rating, battery capacity, and operational policies of the battery are decided based on the assumption that the wind power output follows the Variance Gamma (V.G.) process over short time interval. The histogram of the ramp rates of wind power follows the symmetric Laplace distribution. Furthermore, ramp rates have independent and stationary increments, and their variances are proportional to the time interval. Consequently, the wind power output can be modelled as a simple form of the V.G. process. Battery operational oplicies based on the V.G. process are tested using statistics representing the sum of all wind power outputs from wind farms in the Electric Reliability Council of Texas (ERCOT). It is found that the battery can essentially eliminate violations of ramping limits due to severe ramp events. Furthermore, in this operation, it is discovered that the power rating influences the ramp limiting performance of the battery more than battery storage rating

    Transmission Investment Coordination using MILP Lagrange Dual Decomposition and Auxiliary Problem Principle

    Full text link
    This paper considers the investment coordination problem for the long term transmission capacity expansion in a situation where there are multiple regional Transmission Planners (TPs), each acting in order to maximize the utility in only its own region. In such a setting, any particular TP does not normally have any incentive to cooperate with the neighboring TP(s), although the optimal investment decision of each TP is contingent upon those of the neighboring TPs. A game-theoretic interaction among the TPs does not necessarily lead to this overall social optimum. We, therefore, introduce a social planner and call it the Transmission Planning Coordinator (TPC) whose goal is to attain the optimal possible social welfare for the bigger geographical region. In order to achieve this goal, this paper introduces a new incentive mechanism, based on distributed optimization theory. This incentive mechanism can be viewed as a set of rules of the transmission expansion investment coordination game, set by the social planner TPC, such that, even if the individual TPs act selfishly, it will still lead to the TPC's goal of attaining overall social optimum. Finally, the effectiveness of our approach is demonstrated through several simulation studies

    Dynamic Energy Management

    Full text link
    We present a unified method, based on convex optimization, for managing the power produced and consumed by a network of devices over time. We start with the simple setting of optimizing power flows in a static network, and then proceed to the case of optimizing dynamic power flows, i.e., power flows that change with time over a horizon. We leverage this to develop a real-time control strategy, model predictive control, which at each time step solves a dynamic power flow optimization problem, using forecasts of future quantities such as demands, capacities, or prices, to choose the current power flow values. Finally, we consider a useful extension of model predictive control that explicitly accounts for uncertainty in the forecasts. We mirror our framework with an object-oriented software implementation, an open-source Python library for planning and controlling power flows at any scale. We demonstrate our method with various examples. Appendices give more detail about the package, and describe some basic but very effective methods for constructing forecasts from historical data.Comment: 63 pages, 15 figures, accompanying open source librar

    Comparative Analysis of Viral Gene Expression Programs during Poxvirus Infection: A Transcriptional Map of the Vaccinia and Monkeypox Genomes

    Get PDF
    Poxviruses engage in a complex and intricate dialogue with host cells as part of their strategy for replication. However, relatively little molecular detail is available with which to understand the mechanisms behind this dialogue.We designed a specialized microarray that contains probes specific to all predicted ORFs in the Monkeypox Zaire (MPXV) and Vaccinia Western Reserve (VACV) genomes, as well as >18,000 human genes, and used this tool to characterize MPXV and VACV gene expression responses in vitro during the course of primary infection of human monocytes, primary human fibroblasts and HeLa cells. The two viral transcriptomes show distinct features of temporal regulation and species-specific gene expression, and provide an early foundation for understanding global gene expression responses during poxvirus infection.The results provide a temporal map of the transcriptome of each virus during infection, enabling us to compare viral gene expression across species, and classify expression patterns of previously uncharacterized ORFs

    The body unbound: ritual scarification and autobiographical forms in Wole Soyinka’s Aké: the years of childhood

    Get PDF
    The scarification in Aké is invested with major significance apropos Soyinka’s ideas on African subjectivity. Scarification among the Yoruba is one of the rites of passage associated with personal development. Scarification literally and metaphorically “opens” the person up socially and cosmically. Personal formation and self-realization are enabled by the Yoruba social code brought into being by its mythology. The meaning of the scarification incident in Aké is profoundly different. Determined by the form of autobiography which creates a self-constituting subject, the enabling Yoruba sociocultural context is elided. The story of Soyinka’s personal development is allegorical of the story of the development of the modern African subject. For Soyinka, the African subject is a rational subject whose constitution precludes the splitting of the scientific and spiritual which is a consequence of the Cartesian rupture. The African subject should be open to other subjects and the object world. Subjectivity constituted by the autobiographical mode closes off the opening up symbolically signalled by scarification.Web of Scienc

    Monsters: interdisciplinary explorations in monstrosity

    Get PDF
    There is a continued fascination with all things monster. This is partly due to the popular reception of Mary Shelley’s Monster, termed a “new species” by its overreaching but admiringly determined maker Victor Frankenstein in the eponymous novel first published in 1818. The enduring impact of Shelley’s novel, which spans a plethora of subjects and genres in imagery and themes, raises questions of origin and identity, death, birth and family relationships as well as the contradictory qualities of the monster. Monsters serve as metaphors for anxieties of aberration and innovation. Stephen Asma (2009) notes that monsters represent evil or moral transgression and each epoch, to speak with Michel Foucault, evidences a “particular type of monster” (2003, 66). Academic debates tend to explore how social and cultural threats come to be embodied in the figure of a monster and their actions literalize our deepest fears. Monsters in contemporary culture, however, have become are more humane than ever before. Monsters are strong, resilient, creative and sly creatures. Through their playful and invigorating energy they can be seen to disrupt and unsettle. They still cater to the appetite for horror, but they also encourage us to feel empathy. The encounter with a monster can enable us to stop, wonder and change our attitudes towards technology and our body and each other. This commentary article considers the use of the concepts of ‘monsters’ or ‘monstrosity’ in literature, contemporary research, culture and teaching contexts at the intersection of the Humanities and the Social Sciences

    The Novel Immunosuppressive Protein Kinase C Inhibitor Sotrastaurin Has No Pro-Viral Effects on the Replication Cycle of Hepatitis B or C Virus

    Get PDF
    The pan-protein kinase C (PKC) inhibitor sotrastaurin (AEB071) is a novel immunosuppressant currently in phase II trials for immunosuppression after solid organ transplantation. Besides T-cell activation, PKC affects numerous cellular processes that are potentially important for the replication of hepatitis B virus (HBV) and hepatitis C virus (HCV), major blood-borne pathogens prevalent in solid organ transplant recipients. This study uses state of the art virological assays to assess the direct, non-immune mediated effects of sotrastaurin on HBV and HCV. Most importantly, sotrastaurin had no pro-viral effect on either HBV or HCV. In the presence of high concentrations of sotrastaurin, well above those used clinically and close to levels where cytotoxic effects become detectable, there was a reduction of HCV and HBV replication. This reduction is very likely due to cytotoxic and/or anti-proliferative effects rather than direct anti-viral activity of the drug. Replication cycle stages other than genome replication such as viral cell entry and spread of HCV infection directly between adjacent cells was clearly unaffected by sotrastaurin. These data support the evaluation of sotrastaurin in HBV and/or HCV infected transplant recipients
    corecore