1,045 research outputs found
An architecture for object-oriented intelligent control of power systems in space
A control system for autonomous distribution and control of electrical power during space missions is being developed. This system should free the astronauts from localizing faults and reconfiguring loads if problems with the power distribution and generation components occur. The control system uses an object-oriented simulation model of the power system and first principle knowledge to detect, identify, and isolate faults. Each power system component is represented as a separate object with knowledge of its normal behavior. The reasoning process takes place at three different levels of abstraction: the Physical Component Model (PCM) level, the Electrical Equivalent Model (EEM) level, and the Functional System Model (FSM) level, with the PCM the lowest level of abstraction and the FSM the highest. At the EEM level the power system components are reasoned about as their electrical equivalents, e.g, a resistive load is thought of as a resistor. However, at the PCM level detailed knowledge about the component's specific characteristics is taken into account. The FSM level models the system at the subsystem level, a level appropriate for reconfiguration and scheduling. The control system operates in two modes, a reactive and a proactive mode, simultaneously. In the reactive mode the control system receives measurement data from the power system and compares these values with values determined through simulation to detect the existence of a fault. The nature of the fault is then identified through a model-based reasoning process using mainly the EEM. Compound component models are constructed at the EEM level and used in the fault identification process. In the proactive mode the reasoning takes place at the PCM level. Individual components determine their future health status using a physical model and measured historical data. In case changes in the health status seem imminent the component warns the control system about its impending failure. The fault isolation process uses the FSM level for its reasoning base
An Optimal Algorithm for the Maximum-Density Segment Problem
We address a fundamental problem arising from analysis of biomolecular
sequences. The input consists of two numbers and and a
sequence of number pairs with . Let {\em segment}
of be the consecutive subsequence of between indices and
. The {\em density} of is
. The {\em maximum-density
segment problem} is to find a maximum-density segment over all segments
with . The best
previously known algorithm for the problem, due to Goldwasser, Kao, and Lu,
runs in time. In the present paper, we solve
the problem in O(n) time. Our approach bypasses the complicated {\em right-skew
decomposition}, introduced by Lin, Jiang, and Chao. As a result, our algorithm
has the capability to process the input sequence in an online manner, which is
an important feature for dealing with genome-scale sequences. Moreover, for a
type of input sequences representable in space, we show how to
exploit the sparsity of and solve the maximum-density segment problem for
in time.Comment: 15 pages, 12 figures, an early version of this paper was presented at
11th Annual European Symposium on Algorithms (ESA 2003), Budapest, Hungary,
September 15-20, 200
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Concertino for Jazz Clarinet, Electric Viola and Symphonic Orchestra
Concertino for Jazz Clarinet. Electric viola and Symphonic Orchestra is a composition of approximately fifteen minutes' duration, and is scored for two flutes (second doubling piccolo), two oboes, two Bb clarinets, two bassoons, four F- horns, two Bb trumpets, three trombones (third bass), two percussionists, solo Bb clarinet, solo electric viola and strings. The piece is divided into two movements; Andante and Canon. Concepts derived from jazz music are employed in, for example, harmony and improvisation in the solo parts, whereas the orchestration is mainly traditional. The piece is written for two great Swedish instrumentalists; Putte Wickman, clarinet, and Henrik Frendin, viola. Stylistically this work is difficult in the orchestral parts, since it uses concepts from two different musical styles, jazz and classical. Influences originate from such wide-ranging composers as Mozart, Stravinsky, Shostakovich and Chick Corea
Role of the nitric oxide donor linsidomine chlorhydrate (SIN-1) in the diagnosis and treatment of erectile dysfunction
Flights in my hands : coherence concerns in designing Strip'TIC, a tangible space for air traffic controllers
Best Paper Honorable Mention awardInternational audienceWe reflect upon the design of a paper-based tangible interactive space to support air traffic control. We have observed, studied, prototyped and discussed with controllers a new mixed interaction system based on Anoto, video projection, and tracking. Starting from the understanding of the benefits of tangible paper strips, our goal is to study how mixed physical and virtual augmented data can support the controllers' mental work. The context of the activity led us to depart from models that are proposed in tangible interfaces research where coherence is based on how physical objects are representative of virtual objects. We propose a new account of coherence in a mixed interaction system that integrates externalization mechanisms. We found that physical objects play two roles: they act both as representation of mental objects and as tangible artifacts for interacting with augmented features. We observed that virtual objects represent physical ones, and not the reverse, and, being virtual representations of physical objects, should seamlessly converge with the cognitive role of the physical object. Finally, we show how coherence is achieved by providing a seamless interactive space
Accuracy and Precision of Tidal Wetland Soil Carbon Mapping in the Conterminous United States
Tidal wetlands produce long-term soil organic carbon (C) stocks. Thus for carbon accounting purposes, we need accurate and precise information on the magnitude and spatial distribution of those stocks. We assembled and analyzed an unprecedented soil core dataset, and tested three strategies for mapping carbon stocks: applying the average value from the synthesis to mapped tidal wetlands, applying models fit using empirical data and applied using soil, vegetation and salinity maps, and relying on independently generated soil carbon maps. Soil carbon stocks were far lower on average and varied less spatially and with depth than stocks calculated from available soils maps. Further, variation in carbon density was not well-predicted based on climate, salinity, vegetation, or soil classes. Instead, the assembled dataset showed that carbon density across the conterminous united states (CONUS) was normally distributed, with a predictable range of observations. We identified the simplest strategy, applying mean carbon density (27.0 kg C m−3), as the best performing strategy, and conservatively estimated that the top meter of CONUS tidal wetland soil contains 0.72 petagrams C. This strategy could provide standardization in CONUS tidal carbon accounting until such a time as modeling and mapping advancements can quantitatively improve accuracy and precision
HerdChek Salmonella antibody ELISA for the serological monitoring of Salmonella infection in swine
In this paper we first speculated and later on have proved that the increased number of Salmonella positive results, using the Salmonella Tek-Elisa method as compared to the standard technique, was due to false positive results of the former method. We found out that the higher sensitivity of the former method was due to P.stuartii E. cloacae and E.coli bacteria (CRBs), which cross-reacted with the monoclonal antibodies of the method, giving rise to a higher number of Salmonella false positive results. The purpose of the present study was to identify the source of the higher sensitivity of the Elisa Tek technique and propose corrective steps
The Mechanical Behavior of a 25Cr Super Duplex Stainless Steel at Elevated Temperature
Peer reviewedPostprin
Dose-dependent effects of Allopurinol on human foreskin fibroblast cell and human umbilical vein endothelial cell under hypoxia
Allopurinol, an inhibitor of xanthine oxidase, has been used in clinical trials of patients with cardiovascular and chronic kidney disease. These are two pathologies with extensive links to hypoxia and activation of the transcription factor hypoxia inducible factor (HIF) family. Here we analysed the effects of allopurinol treatment in two different cellular models, and their response to hypoxia. We explored the dose-dependent effect of allopurinol on Human Foreskin Fibroblasts (HFF) and Human Umbilical Vein Endothelial Cells (HUVEC) under hypoxia and normoxia. Under normoxia and hypoxia, high dose allopurinol reduced the accumulation of HIF-1α protein in HFF and HUVEC cells. Allopurinol had only marginal effects on HIF-1α mRNA level in both cellular systems. Interestingly, allopurinol effects over the HIF system were independent of prolyl-hydroxylase activity. Finally, allopurinol treatment reduced angiogenesis traits in HUVEC cells in an in vitro model. Taken together these results indicate that high doses of allopurinol inhibits the HIF system and pro-angiogenic traits in cells
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