1,315 research outputs found
Knowledge-based supervision and control of wastewater treatment plant: a real-time implementation
The hardware architecture and the software development of a real-time knowledge-based
distributed control system for the supervision of a wastewater treatment pilot plant are presented. The
operation scheme is based on an A²/O system (anaerobic, anoxic, oxic) and includes organic matter
removal, nitrification/denitrification, and Enhanced Biological Phosphorous Removal (EBPR). The hardware
architecture involves different supervision levels, including two autonomous process computers (plant
control and analysers control) and a PLC. The software architecture includes a Knowledge-Based Expert
System (KBES) as the top control system. The KBES has been developed in G2, an expert system
development environment based on object-oriented structural design. This system is fed with data obtained
from the plant monitoring (in-line, on-line and off-line data) and with actuation data of the lower control levels.
Using this information, the KBES supervises the pilot plant in order to help with fault detection and plant
maintenance, but also modifies setpoints and other variables of the local control level to adapt the system to
the different influent conditions. The overall system has been implemented and validated at pilot scale.Spanish Inter-Ministry Commission of Science and Technology (C.I.C.Y.T.) - BIO94-0679-C02, AMB97-0889-c03-01.Fundação Calouste Gulbenkian (FCG).Generalitat de Catalunya. Consell Interdepartamental de Recerca i Innovació Tecnològica (CIRIT)
Real-time expert control of a pilot WWTP with nitrogen and phosphorus removal
Fundação Calouste Gulbenkian; C.I.R.I.T. (Generalitat de Catalunya)
Knowledge-based supervision and control of WWTP: a real-time implementation
Fundação Calouste Gulbenkian (FCG) - post-doctoral research grant.Generalitat de Catalunya. Consell Interdepartamental de Recerca i Innovació Tecnològica (CIRIT) - predoctoral fellowship
A knowledge-based distributed system for supervision and control of wastewater treatment processes
This paper presents the hardware architecture and the software development of a real-time knowledge-based
distributed control system for the supervision of a wastewater treatment pilot plant with biological removal of
organic matter and nitrogen. A continuous monitoring of plant and controls data is used by an expert system
developed in G2, a development environment based on object-oriented paradigm. A set of rules and
procedures to help fault detection, plant maintenance, and nitrification - denitrification cycle operation was
implemented and validated at pilot scale. The hardware architecture includes different supervision levels,
including two autonomous process computers (plant control and analysers control).Fundação Calouste Gulbenkian (FCG) - postdoctoral
research grant..Generalitat de Catalunya. Consell Interdepartamental de Recerca i Innovació Tecnològica (CIRIT) - predoctoral fellowship
Revisiting the Problem of Searching on a Line
We revisit the problem of searching for a target at an unknown location on a
line when given upper and lower bounds on the distance D that separates the
initial position of the searcher from the target. Prior to this work, only
asymptotic bounds were known for the optimal competitive ratio achievable by
any search strategy in the worst case. We present the first tight bounds on the
exact optimal competitive ratio achievable, parameterized in terms of the given
bounds on D, along with an optimal search strategy that achieves this
competitive ratio. We prove that this optimal strategy is unique. We
characterize the conditions under which an optimal strategy can be computed
exactly and, when it cannot, we explain how numerical methods can be used
efficiently. In addition, we answer several related open questions, including
the maximal reach problem, and we discuss how to generalize these results to m
rays, for any m >= 2
Data Portraits and Intermediary Topics: Encouraging Exploration of Politically Diverse Profiles
In micro-blogging platforms, people connect and interact with others.
However, due to cognitive biases, they tend to interact with like-minded people
and read agreeable information only. Many efforts to make people connect with
those who think differently have not worked well. In this paper, we
hypothesize, first, that previous approaches have not worked because they have
been direct -- they have tried to explicitly connect people with those having
opposing views on sensitive issues. Second, that neither recommendation or
presentation of information by themselves are enough to encourage behavioral
change. We propose a platform that mixes a recommender algorithm and a
visualization-based user interface to explore recommendations. It recommends
politically diverse profiles in terms of distance of latent topics, and
displays those recommendations in a visual representation of each user's
personal content. We performed an "in the wild" evaluation of this platform,
and found that people explored more recommendations when using a biased
algorithm instead of ours. In line with our hypothesis, we also found that the
mixture of our recommender algorithm and our user interface, allowed
politically interested users to exhibit an unbiased exploration of the
recommended profiles. Finally, our results contribute insights in two aspects:
first, which individual differences are important when designing platforms
aimed at behavioral change; and second, which algorithms and user interfaces
should be mixed to help users avoid cognitive mechanisms that lead to biased
behavior.Comment: 12 pages, 7 figures. To be presented at ACM Intelligent User
Interfaces 201
Cytomegalovirus erosive gastritis in a healthy infant: update about a case
El citomegalovirus es un virus ADN de la familia Herpesviridae
que puede afectar al tubo digestivo. Dentro de éste, las dianas
de afectación suelen ser el colon, el esófago y el estómago. Se
ha descrito ampliamente su asociación con el síndrome de Ménétrier
(hiperplasia foveolar con pérdida de proteínas), si bien
también puede producir cuadros de gastritis erosiva. En el presente
artículo se describe un caso de gastritis erosiva en una
lactante sana de 4 meses de edad, que se inició en forma de
hemorragia digestiva alta. A partir de este caso, se lleva a cabo
una puesta al día de este subgrupo de infecciones por citomegalovirusCytomegalovirus is a DNA Herpesviridae family which can
affect the digestive tract. From the standpoint of the stomach,
has been widely described his association with Ménétrier syndrome
(foveolar hyperplasia with protein-losing) but can also
produce erosive gastritis. This article describes a case of erosive
gastritis in a healthy 4 months infant which debuted as
upper gastrointestinal bleeding. In addition we perform an update
of this subgroup of cytomegalovirus infection
Fast Two-Robot Disk Evacuation with Wireless Communication
In the fast evacuation problem, we study the path planning problem for two
robots who want to minimize the worst-case evacuation time on the unit disk.
The robots are initially placed at the center of the disk. In order to
evacuate, they need to reach an unknown point, the exit, on the boundary of the
disk. Once one of the robots finds the exit, it will instantaneously notify the
other agent, who will make a beeline to it.
The problem has been studied for robots with the same speed~\cite{s1}. We
study a more general case where one robot has speed and the other has speed
. We provide optimal evacuation strategies in the case that by showing matching upper and lower bounds on the
worst-case evacuation time. For , we show (non-matching)
upper and lower bounds on the evacuation time with a ratio less than .
Moreover, we demonstrate that a generalization of the two-robot search strategy
from~\cite{s1} is outperformed by our proposed strategies for any .Comment: 18 pages, 10 figure
Comparative karyotypic analysis in the Alstroemeria hookeri Lodd. (Alstroemeriaceae) complex sensu Bayer (1987)
Carbon dioxide enrichment: a technique to mitigate the negative effects of salinity on the productivity of high value tomatoes
The present study was conducted to determine the mitigating influence of greenhouse CO2 enrichment on the negative effects of salinity in Mediterranean conditions. Hybrid Raf (cv. Delizia) tomato plants were exposed to two salinity levels of the nutrient solution (5 and 7 dS/m) obtained by adding NaCl, and two CO2 concentrations (350 and 800 μmol/mol) in which CO2 enrichment was applied during the daytime according to a strategy linked to ventilation. Increasing water salinity negatively affected the leaf area index (LAI), the specific leaf area (SLA), the water use efficiency (WUE), the radiation use efficiency (RUE) and dry weight (DW) accumulation resulting in lower marketable yield. The high salinity treatment (7 dS/m) increased fruit firmness (N), total soluble solids content (SSC) and titratable acidity (TA), whereas pH was reduced in the three ripening stages: mature green/breaker (G), turning (T), and pink/light red (P). Also, the increase in electrical conductivity of the nutrient solution led to a general change in intensity of the sensory characteristics of tomato fruits. On the other hand, CO2 enrichment did not affect LAI although SLA was reduced. RUE and DW accumulation were increased resulting in higher marketable yield, through positive effects on fruit number and their average weight. WUE was enhanced by CO2 supply mainly through increased growth and yield. Physical-chemical quality parameters such as fruit firmness, TA and pH were not affected by CO2 enrichment whereas SSC was enhanced. Greenhouse CO2 enrichment did mitigate the negative effect of saline conditions on productivity without compromising organoleptic and sensory fruit quality
- …