872 research outputs found

    The capacity of multilevel threshold functions

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    Lower and upper bounds for the capacity of multilevel threshold elements are estimated, using two essentially different enumeration techniques. It is demonstrated that the exact number of multilevel threshold functions depends strongly on the relative topology of the input set. The results correct a previously published estimate and indicate that adding threshold levels enhances the capacity more than adding variables

    Construction of a variable micro-nano-gap instrument for chemical reaction studies and mimicking of possible NAE like structures

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    Scanning tunnelling microscope is a versatile instrument to study surface atom structures and surface electron structures. The principles of its operation can be used to develop a variation where two surfaces of micron scale are brought in very close proximity of few atom lengths to each other. There are many technical challenges involved in such construction that will be reported. Experience in unconventional STM construction will be used in this case

    Psychiatric morbidity in epilepsy: a case controlled study of adults receiving disability benefits

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldOBJECTIVE: To compare the prevalence of non-organic psychiatric disorders among disabled patients of normal intelligence with epilepsy with the prevalence of similar psychiatric disorders among age and sex matched disabled patients with other somatic diseases. METHODS: A case-control study was carried out in Iceland among people receiving disability benefits using information available at the State Social Security Institute. There were 344 patients with epilepsy in Iceland 16 to 66 years of age (inclusive) receiving disability benefits in 1995. By excluding mentally retarded patients, autistic patients, and patients with organic psychoses, 241 index cases with epilepsy qualified for the study. For each case two age and sex matched controls were selected from all patients receiving disability benefits who had cardiovascular diseases, respiratory diseases, or arthropathies. The same exclusion criteria were applied to the controls as the index cases. In both patient groups psychiatric diagnoses were classified into one of the four following categories: (1) psychotic illness; (2) neurotic illness or personality disorders; (3) alcohol or drug dependence or misuse; and (4) other mental disorders. RESULTS: Psychiatric diagnosis was present among 35% (85/241) of the cases compared with 30% (143/482) of the controls (p=0.15). There was a difference in the distribution of the two groups into different psychiatric categories (p=0.02). This was mainly due to an excess of men in the index group with psychosis, particularly schizophrenia or paranoid states. CONCLUSION: The results suggest that there is not a difference in the prevalence of non-organic psychiatric disorders among disabled patients of normal intelligence with epilepsy compared with patients with other disabling somatic diseases. However, the data indicate that when psychopathology is present disabled patients with epilepsy are more likely to have psychotic illness than the other disabled patients

    Nonlinear Dynamics in Distributed Systems

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    We build on a previous statistical model for distributed systems and formulate it in a way that the deterministic and stochastic processes within the system are clearly separable. We show how internal fluctuations can be analysed in a systematic way using Van Kanpen's expansion method for Markov processes. We present some results for both stationary and time-dependent states. Our approach allows the effect of fluctuations to be explored, particularly in finite systems where such processes assume increasing importance.Comment: Two parts: 8 pages LaTeX file and 5 (uuencoded) figures in Postscript forma

    Situation-aware wireless networks

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    Strong ground motion from the seismic swarms preceding the 2021 and 2022 volcanic eruptions at Fagradalsfjall, Iceland

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    The Geldingadalir and Meradalir eruptions at Mt. Fagradalsfjall in the Reykjanes Peninsula on 19 March 2021 and 3 August 2022, respectively, were preceded by intense volcano-tectonic swarms. Eight earthquakes with M ≥ 5 were recorded by the Icelandic Strong Motion Network. We present an overview of the seismicity in Fagradalsfjall, and salient features of the strong ground motion caused by the swarms in the epicentral area. The largest recorded horizontal Peak Ground Acceleration (PGA) was ~ 0.45 g at Grindavík, which is the strongest PGA recorded in Iceland since the MW6.3 2008 Ölfus Earthquake. Recorded waveforms show a rich long-period energy content, with a burst of higher frequencies at the beginning of shaking. This leads to larger response spectral accelerations at long periods that those from typical shallow crustal earthquakes. Moreover, an empirical mixed-effects ground motion model for PGA, PGV and PSA was calibrated for rock sites based on the available recordings. The attenuation rate from this model is similar to that introduced by Lanzano and Luzi (Bull Earthq Eng 18(1):57–76, 2020) which is based on data from volcanic events in Italy, but the magnitude scaling of our model is much lower. The overall results indicate that scaling and attenuation of ground motion from volcanic events and purely tectonic earthquakes in Iceland are different. This is an important observation because seismic hazard in parts of the Reykjavik area and of the central highlands, where important hydroelectric power plants are located, could potentially be dominated by events of volcanic origin. Therefore, it is important to take these observations into account for seismic hazard and risk assessment in Iceland

    The capacity of multilevel threshold functions

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    THREE MAIN SPATIAL TECHNIQUES of SPATIAL MIXING SYSTEM

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    This written review is to have a deep review for three techniques to realize spatial effects, which are Head Related Transfer Functions, Image Source Method, and Schroeder Reverberation, utilized in Spatial Mixing System, 2nd lab report.Architecture & Allied Art

    Freshwater composition of the waters off southeast Greenland and their link to the Arctic Ocean

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    Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C05020, doi:10.1029/2008JC004808.The freshwater composition of waters on the southeast Greenland shelf and slope are described using a set of high-resolution transects occupied in summer 2004, which included hydrographic, velocity, nutrient, and chemical tracer measurements. The nutrient and tracer data are used to quantify the fractions of Pacific Water, sea ice melt, and meteoric water present in the upper layers of the East Greenland Current (EGC) and East Greenland Coastal Current (EGCC). The EGC/EGCC system dominates the circulation of this region and strongly influences the observed distribution of the three freshwater types. Sea ice melt and meteoric water fractions are surface intensified, reflecting their sources, and generally increase southward from Denmark Strait to Cape Farewell, as well as shoreward. Significant fractions of Pacific Water are found in the subsurface layers of the EGCC, supporting the idea that this inner shelf branch is directly linked to the EGC and thus to the Arctic Ocean. A set of historical sections is examined to investigate the variability of Pacific Water content in the EGC and EGCC from 1984 to 2004 in the vicinity of Denmark Strait. The fraction of Pacific Water increased substantially in the late 1990s and subsequently declined to low levels in 2002 and 2004, mirroring the reduction in Pacific Water content reported previously at Fram Strait. This variability is found to correlate significantly with the Arctic Oscillation index, lagged by 9 years, suggesting that the Arctic Ocean circulation patterns bring varying amounts of Pacific Water to the North Atlantic via the EGC/EGCC.This work was funded by National Science Foundation grant OCE- 0450658. D. Sutherland also received support from the Woods Hole Oceanographic Institution Academic Programs Office
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