13,449 research outputs found
Modelling Cell Cycle using Different Levels of Representation
Understanding the behaviour of biological systems requires a complex setting
of in vitro and in vivo experiments, which attracts high costs in terms of time
and resources. The use of mathematical models allows researchers to perform
computerised simulations of biological systems, which are called in silico
experiments, to attain important insights and predictions about the system
behaviour with a considerably lower cost. Computer visualisation is an
important part of this approach, since it provides a realistic representation
of the system behaviour. We define a formal methodology to model biological
systems using different levels of representation: a purely formal
representation, which we call molecular level, models the biochemical dynamics
of the system; visualisation-oriented representations, which we call visual
levels, provide views of the biological system at a higher level of
organisation and are equipped with the necessary spatial information to
generate the appropriate visualisation. We choose Spatial CLS, a formal
language belonging to the class of Calculi of Looping Sequences, as the
formalism for modelling all representation levels. We illustrate our approach
using the budding yeast cell cycle as a case study
José Carlos de Andrade (5/28/1942 - 6/11/2008)
UNIFESPUNIFESPSciEL
Quality of Service Controlled Multimedia Transport Protocol
PhDThis research looks at the design of an open transport protocol that supports a range of
services including multimedia over low data-rate networks. Low data-rate multimedia
applications require a system that provides quality of service (QoS) assurance and flexibility.
One promising field is the area of content-based coding. Content-based systems use an array
of protocols to select the optimum set of coding algorithms. A content-based transport
protocol integrates a content-based application to a transmission network.
General transport protocols form a bottleneck in low data-rate multimedia
communicationbsy limiting throughpuot r by not maintainingt iming requirementsT. his work
presents an original model of a transport protocol that eliminates the bottleneck by
introducing a flexible yet efficient algorithm that uses an open approach to flexibility and
holistic architectureto promoteQ oS.T he flexibility andt ransparenccyo mesi n the form of a
fixed syntaxt hat providesa seto f transportp rotocols emanticsT. he mediaQ oSi s maintained
by defining a generic descriptor. Overall, the structure of the protocol is based on a single
adaptablea lgorithm that supportsa pplication independencen, etwork independencea nd
quality of service.
The transportp rotocol was evaluatedth rougha set of assessmentos:f f-line; off-line
for a specific application; and on-line for a specific application. Application contexts used
MPEG-4 test material where the on-line assessmenuts eda modified MPEG-4 pl; yer. The
performanceo f the QoSc ontrolledt ransportp rotocoli s often bettert hano thers chemews hen
appropriateQ oS controlledm anagemenatl gorithmsa re selectedT. his is shownf irst for an
off-line assessmenwt here the performancei s compared between the QoS controlled
multiplexer,a n emulatedM PEG-4F lexMux multiplexers chemea, ndt he targetr equirements.
The performanceis also shownt o be better in a real environmentw hen the QoS controlled
multiplexeri s comparedw ith the real MPEG-4F lexMux scheme
Transcritical Carbon Dioxide Charge-Discharge Energy Storage with Integration of Solar Energy
New and improved energy storage technologies are required to overcome
non-dispatchability, which is the main challenge for the successful integration of large
shares of renewable energy within energy supply systems. Energy storage is proposed to
tackle daily variations on the demand side, i.e., storing low-price energy during off-peak
or valley periods for utilization during peak periods. Regarding electrical energy storage,
several technologies are available with different potentials for scalability, density, and
cost. A recent approach for grid-scale applications is based on transcritical carbon
dioxide charge and discharge cycles in combination with thermal energy storage systems.
This alternative to pumped-hydro and compressed air energy storage has been discussed
in scientific literature, where different configurations have been proposed and their
efficiency and costs calculated. The potential of the concept has been demonstrated to be
an economical alternative, including hybrid concepts with solar thermal storage. Even at
low temperatures, the addition of solar energy has proved to be cost effective. This paper
explores the effect of introducing solar-based high temperature heat on the performance
of different configurations of “Transcritical carbon dioxide ‒ thermal energy storage
system” cycles. A base-cycle with 8-hour discharge time is compared with different
layouts. Discussions include details on the models, parametric analyses -including solar
technology alternatives-, and simulation results. Round trip efficiency of the base case,
without solar support and at pressure ratio of 9.4, is 52%. When solar input is considered,
the efficiency is above 60%, increasing the turbine inlet temperature to 950 K. Estimated
levelized cost of electricity values are in the range of pumped hydro and compressed air
energy storage, 90-140 USD/MWh in agreement with other works on this thermal storage
technology. The global analysis shows clear advantages for advancing in the study and
definition of this technology for exploitation of synergies at different power ranges,
integrated with mid/high temperature solar power plants and with smaller-scale
renewable installations.Unión Europea. Fondo Europeo de Desarrollo Regional SOE1 / P3 / P0429E
Incidencia de HIV no banco de leite da maternidade Carmela Dutra de Florianópolis - SC.
Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Departamento de Tocoginecologia, Curso de Medicina, Florianópolis, 199
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