1,304 research outputs found
Improvement of messages delivery time on vehicular delay-tolerant networks
“Copyright © [2009] IEEE. Reprinted from International Conference on Parallel Processing Workshops ICPPW '09.ISSN:1530-2016. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”Vehicular Delay-Tolerant Networks (VDTNs) are an application of the Delay-Tolerant Network (DTN) concept, where the movement of vehicles and their message relaying service is used to enable network connectivity under unreliable conditions. To address the problem of intermittent connectivity, long-term message storage is combined with routing schemes that replicate messages at transfer opportunities. However, these strategies can be inefficient in terms of network resource usage. Therefore, efficient scheduling and dropping policies are necessary to improve the overall network performance. This work presents a performance analysis, based on simulation, of the impact of different scheduling and dropping policies enforced on Epidemic and Spray and Wait routing schemes. This paper evaluates these policies from the perspective of their efficiency in reducing the message’s end-to-end delay. In our scenario, it is shown that when these policies are based on the message’s lifetime criteria, the message average delay decreases significantly and the overall message delivery probability also increases for both routing protocols. Further simulations show that these results outperform the MaxProp and PRoPHET routing protocols that have their own scheduling and dropping mechanisms.Part of this work has been supported by Instituto de Telecomunicações, Next Generation Networks and Applications Group, Portugal, in the framework of the VDTN@Lab Project, and by the Euro-NF Network of Excellence from the Seventh Framework Programme of EU
Crescimento e qualidade da carcaça de suinos Landrace X Large White submetidos a acabamento intensivo até elevado peso de abate
Ao longo dos últimos anos, em muitos países, e como já é habitual em Itália, o peso vivo de abate de
suínos tem registado um progressivo aumento, o que tem sido possível devido ao melhoramento
genético de raças industriais, com potencial para produzir mais carne magra.
Utilizaram-se 30 suínos, F1 cruzados de Landrace x Large White, castrados, submetidos a
acabamento intensivo com alimento composto (Energia Bruta 3833 kcal / kg MS), distribuído ad
libitum, até um peso elevado ao abate (90-160 kg de PV). Avaliou-se o desempenho produtivo dos
animais, espessura da gordura e profundidade do Longissimus dorsi, in vivo, e peso de carcaça. Os
animais foram pesados semanalmente e a ingestão de alimento controlada, individual e diariamente,
permitindo calcular os GMD e IC. Efetuaram-se diversas medições, in vivo, da espessura da gordura
(P1 - linha média da última vertebra torácica, P2 - a 6 cm da linha média ao nível da última vertebra
torácica e P3 - linha média da última vertebra lombar) e da profundidade do Longissimus dorsi, por
ultra-sonografia, aos 90, 120 e 160 kg PV. Os animais foram abatidos em matadouro experimental,
registando-se o peso de carcaça, a quente e a frio (24 h post mortem), bem como o total das
gorduras rejeitadas e miudezas.
Os GMD dos animais foram de 828,3 ± 110,3 g e de 673,1 ± 112,2 g, nos períodos 90-120 kg e 120-
160 kg, respetivamente, o que representa um decréscimo de 19% do GMD, entre os períodos
considerados. Nos mesmos períodos, os IC foram de 4,27 ± 0,32 e de 4,99 ± 0,49, representando um
incremento de 17%. O consumo médio de alimento foi de 3,34 kg / dia. Para as três medições de
espessura da gordura efetuadas e da profundidade do Longissimus dorsi, registou-se um crescimento
constante ao longo do ensaio, no total de 1,1 cm, e de 1,2 cm, respetivamente. Observou-se apenas
uma diferenciação do crescimento do P2, menos acentuado entre os 90 e os 120 kg, mas
recuperando, no período 120-160 Kg. Os pesos médios da carcaça, a quente e a frio, foram
respectivamente 132,1 Kg e 130 kg, representando 82,4% e 81% do peso vivo ao abate. Obteve-se
um peso médio da perna (com chispe) de 19 kg.
Os resultados obtidos indiciam uma possível utilização deste cruzamento na produção de suínos em
sistema intensivo com objetivo de produção de pernas para presunto e com aproveitamento das
restantes peças cárneas.info:eu-repo/semantics/publishedVersio
Evaluating simulated annealing algorithms in the optimization of bacterial strains
In this work, a Simulated Annealing (SA) algorithm is proposed
for a Metabolic Engineering task: the optimization of the set of
gene deletions to apply to a microbial strain to achieve a desired production
goal. Each mutant strain is evaluated by simulating its phenotype
using the Flux-Balance Analysis approach, under the premise that microorganisms
have maximized their growth along natural evolution. A
set based representation is used in the SA to encode variable sized solutions,
enabling the automatic discovery of the ideal number of gene
deletions. The approach was compared to the use of Evolutionary Algorithms
(EAs) to solve the same task. Two case studies are presented
considering the production of succinic and lactic acid as the target, with
the bacterium E. coli. The variable sized SA seems to be the best alternative,
outperforming the EAs, showing a fast convergence and low
variability among the several runs and also enabing the automatic discovery
of the ideal number of knockouts.FEDER.Portuguese Foundation for Science and Technology (FCT) - POSC/EIA/59899/2004
Shear-induced lamellar ionic liquid-crystal foam
n a recent paper we reported an experimental study of two N-alkylimidazolium salts. These ionic compounds exhibit liquid crystalline behaviour with melting points above 50 degrees C in bulk. However, if they are sheared, a (possibly non-equilibrium) lamellar phase forms at room temperature. Upon shearing a thin film of the material between microscope slides, textures were observed that are strikingly similar to liquid (wet) foams. The images obtained from polarising optical microscopy (POM) were found to share many of the known quantitative properties of a two-dimensional foam coarsening process. Here we report an experimental study of this foam using a shearing system coupled with POM. The structure and evolution of the foam are investigated through the image analysis of time sequences of micrographs obtained for well-controlled sets of physical parameters (sample thickness, shear rate and temperature). In particular, we find that there is a threshold shear rate below which no foam can form. Above this threshold, a steady-state foam pattern is obtained where the mean cell area generally decreases with increasing shear rate. Furthermore, the steady-state internal cell angles and distribution of the cell number of sides deviate from their equilibrium (i.e. zero-shear) values
Evolução e estrutura da zona de cisalhamento dúctil Malpica-Lamego : livro guia da excursão pós-congresso
Multivariate monitoring of an activated sludge process for biological treatment of a synthetic wastewater effluent
From chickpea and lupin as dairy alternatives
Funding text This work was supported by the FCT Project PTDC/BAA-AGR/28370/2017: “Bebida de proteína vegetal a partir de leguminosas europeias com potencial bioativo”; and also through the research unit UID/AGR/04129/2020 – LEAF.Consumption of plant based products as dairy alternatives is increasing steeply. This diet transition can only be achieved if these products keep the nutritional value and meet consumer's sensory acceptance. This work aimed to evaluate the decrease of the “beany” flavour and of raffinose, stachyose and verbascose contents in EU pulse beveragés production, and also the best lactic fermentation conditions of the beverages, towards chickpea- and lupin-based yoghurts, with rheology properties similar to the commercial soy yoghurts. The reduction of “beany” volatile compounds of chickpea and lupin beverages during processing was confirmed through GC–MS analysis. Soaking and cooking processes were effective in removing flatulence sugars with almost 48% loss from the initial content in lupin beverage. The fermentation conditions at 40 °C, 12 h and 2% (w/v) of starter concentration evidenced the best viscoelastic structure and flow properties. The lupin yoghurt-type showed a similar gel structure to commercial soy yoghurt. © 2022publishersversionpublishe
Portuguese and Brazilian stock market integration : a non-linear and detrended approach
Besides the historical heritage that Portugal and Brazil share, the last two decades have also shown an increase in some economic indicators, such as the percentage of imports/exports and foreign direct investment. In order to take advantage of all the benefits, the countries should increase economic integration, stock market integration being one of the possibilities. In this context, this paper analyses stock market integration between these two countries, using non-linear methodologies: detrended fluctuation analysis, detrended cross-correlation analysis and detrended moving-average cross-correlation analysis. Using the main stock indexes, and splitting the sample in six different periods, the main conclusion is that integration between these two countries increased over time. However, since 2013, the integration pattern has decreased, with the economic crisis both countries suffered being the main factor.info:eu-repo/semantics/publishedVersio
Reference Model in BPMN Notation for a Production Scheduling System
Companies are progressively investing in practices aimed at improving the quality of management, with the main purpose of enabling them to operate competitively in the present market. For this, it is necessary to document the activities and information of the existing business processes in the organization, aiming at reducing time and cost in the elaboration of the particular model. In this context, the objective of this work is to develop a reference model of the Production Scheduling (PS) processes, an important module of production planning and control (PPC). The research methodology used in this work was divided into the following stages: study of PS and business process modeling, definition of reference model processes, choice of methodology and process modeling tool, development of reference model and prototype of the software and, finally, analysis of results. The modeling notation used was the BPMN, since it is considered a standard language in the field of process modeling. The prototype was developed through the Delphi interface in order to apply the model to support the implementation of business management programs. As results, from a formal documentation, the model proved to be a useful mechanism in the understanding of the processes raised and appropriate in the support to the implantation of production management tools
- …