69 resultados para Buck-Boost inverter


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Cyber-attacks against Smart Grids have been found in the real world. Malware such as Havex and BlackEnergy have been found targeting industrial control systems (ICS) and researchers have shown that cyber-attacks can exploit vulnerabilities in widely used Smart Grid communication standards. This paper addresses a deep investigation of attacks against the manufacturing message specification of IEC 61850, which is expected to become one of the most widely used communication services in Smart Grids. We investigate how an attacker can build a custom tool to execute man-in-the-middle attacks, manipulate data, and affect the physical system. Attack capabilities are demonstrated based on NESCOR scenarios to make it possible to thoroughly test these scenarios in a real system. The goal is to help understand the potential for such attacks, and to aid the development and testing of cyber security solutions. An attack use-case is presented that focuses on the standard for power utility automation, IEC 61850 in the context of inverter-based distributed energy resource devices; especially photovoltaic (PV) generators.

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The paper investigates the dynamics and volution of issues on the agenda of Baltic environmental non-governmental organisations (NGOs) since the collapse of communism. The past research on Baltic environment activism suggests that these enjoy high visibility because they tapped the core societal views of natural environment as a crucial asset of a nation. As we demonstrate in this paper, the changes in agendas of Baltic environmental non-governmental organisations (ENGOs) make clear that the rhetorical toolbox of ‘national environment’ is often used to mainly achieve greater financial gains for individual members, rather than for society at large. We illustrate how the dearth of economic opportunities for domestic public has impacted perceptions of ‘nature’ advocated by the environmental activists, focussing specifically on national perceptions of ownership and the resulting actions appropriating ‘nature’ as a source for economic development, only tangentially attaining environmental outcomes on the way. The vision that the ‘environment’ is an economic resource allowed ENGO activists to cooperate with the domestic policymaking, while tapping international networks and donors for funding. Throughout the past decades they worked to secure their own and their members' particularistic economic interests and, as we demonstrate, remained disengaged from the political process and failed to develop broader reproach with publics.

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Background: Many school-based interventions are being delivered in the absence of evidence of effectiveness (Snowling & Hulme, 2011, Br. J. Educ. Psychol., 81, 1).Aim: This study sought to address this oversight by evaluating the effectiveness of the commonly used the Lexia Reading Core5 intervention, with 4- to 6-year-old pupils in Northern Ireland.Sample: A total of 126 primary school pupils in year 1 and year 2 were screened on the Phonological Assessment Battery 2nd Edition (PhAB-2). Children were recruited from the equivalent year groups to Reception and Year 1 in England and Wales, and Pre-kindergarten and Kindergarten in North America.
Methods: A total of 98 below-average pupils were randomized (T0) to either an 8-week block (inline image = 647.51 min, SD = 158.21) of daily access to Lexia Reading Core5 (n = 49) or a waiting-list control group (n = 49). Assessment of phonological skills was completed at post-intervention (T1) and at 2-month follow-up (T2) for the intervention group only.
Results: Analysis of covariance which controlled for baseline scores found that the Lexia Reading Core5 intervention group made significantly greater gains in blending, F(1, 95) = 6.50, p = .012, partial η2 = .064 (small effect size) and non-word reading, F(1, 95) = 7.20, p = .009, partial η2 = .070 (small effect size). Analysis of the 2-month follow-up of the intervention group found that all group treatment gains were maintained. However, improvements were not uniform among the intervention group with 35% failing to make progress despite access to support. Post-hoc analysis revealed that higher T0 phonological working memory scores predicted improvements made in phonological skills.
Conclusions: An early-intervention, computer-based literacy program can be effective in boosting the phonological skills of 4- to 6-year-olds, particularly if these literacy difficulties are not linked to phonological working memory deficits.

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New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring samples, converted with a box diffusion model to marine mixed-layer ages, cover the period from 0–10.5 cal kyr BP. Beyond 10.5 cal kyr BP, high-resolution marine data become available from foraminifera in varved sediments and U/Th-dated corals. The marine records are corrected with site-specific 14C reservoir age information to provide a single global marine mixed-layer calibration from 10.5–26.0 cal kyr BP. A substantial enhancement relative to IntCal98 is the introduction of a random walk model, which takes into account the uncertainty in both the calendar age and the 14C age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed here. The tree-ring data sets, sources of uncertainty, and regional offsets are presented in detail in a companion paper by Reimer et al. (this issue).

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Recent measurements on dendrochronologically-dated wood from the Southern Hemisphere have shown that there are differences between the structural form of the radiocarbon calibration curves from each hemisphere. Thus, it is desirable, when possible, to use calibration data obtained from secure dendrochronologically-dated wood from the corresponding hemisphere. In this paper, we outline the recent work and point the reader to the internationally recommended data set that should be used for future calibration of Southern Hemisphere 14C dates.

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The potential of intensity modulated radiotherapy (IMRT) to improve the therapeutic ratio in prostate cancer by dose escalation of intraprostatic tumour nodules (IPTNs) was investigated using a simultaneous integrated boost technique. The prostate and organs-at-risk were outlined on CT images from six prostate cancer patients. Positions of IPTNs were transferred onto the CT images from prostate maps derived from sequential large block sections of whole prostatectomy specimens. Inverse planned IMRT dose distributions were created to irradiate the prostate to 70 Gy and all the IPTNs to 90 Gy. A second plan was produced to escalate only the dominant IPTN (DIPTN) to 90 Gy, mimicking current imaging techniques. These plans were compared with homogeneous prostate irradiation to 70 Gy using dose–volume histograms, tumour control probability (TCP) and normal tissue complication probability (NTCP) for the rectum. The mean dose to IPTNs was increased from 69.8 Gy to 89.1 Gy if all the IPTNs were dose escalated (p=0.0003). This corresponded to a mean increase in TCP of 8.7–31.2% depending on the /ß ratio of prostate cancer (p

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A new calibration curve for the conversion of radiocarbon ages to calibrated (cal) ages has been constructed and internationally ratified to replace IntCal98, which extended from 0-24 cal kyr BP (Before Present, 0 cal BP = AD 1950). The new calibration data set for terrestrial samples extends from 0-26 cal kyr BP, but with much higher resolution beyond 11.4 cal kyr BP than IntCal98. Dendrochronologically-dated tree-ring samples cover the period from 0-12.4 cal kyr BP. Beyond the end of the tree rings, data from marine records (corals and foraminifera) are converted to the atmospheric equivalent with a site-specific marine reservoir correction to provide terrestrial calibration from 12.4-26.0 cal kyr BP. A substantial enhancement relative to IntCal98 is the introduction of a coherent statistical approach based on a random walk model, which takes into account the uncertainty in both the calendar age and the (super 14) C age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The tree-ring data sets, sources of uncertainty, and regional offsets are discussed here. The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed in brief, but details are presented in Hughen et al. (this issue a). We do not make a recommendation for calibration beyond 26 cal kyr BP at this time; however, potential calibration data sets are compared in another paper (van der Plicht et al., this issue).

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Micro plasmas operated at ambient pressure with dimensions of the confining geometry in the order of a few ten micrometers to a millimeter are actually in the focus of interest due to the broad regime of applicability they offer and due to a similarly broad range of open physical questions. Here we present optical measurements within the discharge core and the effluent region of an especially developed micro discharge jet. To get an understanding of the complex system of this discharge it is important to analyse transport phenomena of energy and particles within both parts of the discharge by various highly sophisticated diagnostics. As a consequence of the limited access and the dimensions of the micro discharge most of these diagnostics are optical. Here we present diagnostics applied to determine spatially resolved absolute atomic oxygen densities as the most reactive constituent of the effluent, density maps of ozone as final reaction product of the gas chemical chain induced by the discharge and phase resolved optical emission spectroscopy yielding insight into the excitation dynamics of the discharge. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim.

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An increasing understanding of the process of erythropoiesis raises some interesting questions about the pathophysiology, diagnosis and treatment of anemia and erythrocytosis. The mechanisms underlying the development of many of the erythrocytoses, previously characterised as idiopathic, have been elucidated leading to an increased understanding of oxygen homeostasis. Characterisation of anemia and erythrocytosis in relation to serum erythropoietin levels can be a useful addition to clinical diagnostic criteria and provide a rationale for treatment with erythropoiesis stimulating agents (ESAs). Recombinant human erythropoietin as well as other ESAs are now widely used to treat anemias associated with a range of conditions, including chronic kidney disease, chronic inflammatory disorders and cancer. There is also heightened awareness of the potential abuse of ESAs to boost athletic performance in competitive sport. The discovery of erythropoietin receptors outside of the erythropoietic compartment may herald future applications for ESAs in the management of neurological and cardiac diseases. The current controversy concerning optimal hemoglobin levels in chronic kidney disease patients treated with ESAs and the potential negative clinical outcomes of ESA treatment in cancer reinforces the need for cautious evaluation of the pleiotropic effects of ESAs in non-erythroid tissues.