Real-time control of a laboratory heat exchanger using the particle swarm optimisation algorithm

In the past decade, evolutionary based algorithms have been a popular research theme in many disciplinary areas like control systems. Although, due to the computational load required, this type of algorithms usually are applied off-line. In this paper, a stochastic search algorithm known as particle swarm is used as an optimisation tool for on-line control of a custom made laboratory thermodynamic system

Greenhouse air temperature control using the particle swarm optimisation algorithm

The particle swarm optimisation algorithm is proposed as a new method to design a model based predictive controller subject to restrictions. Its performance is compared with the one obtained by using a genetic algorithm for the environmental temperature control of a greenhouse. Controller outputs are computed in order to optimise future behaviour of the greenhouse environment, regarding set-point tracking and minimisation of the control effort over a prediction horizon of one hour with a one-minute sampling period

Hardware-in-the-loop control using the particle swarm optimisation

In the last two decades, evolutionary based algorithms have proved to be an important tool in solving optimisation problems in many disciplinary areas namely in control system design. However one of its limitations, for some type of applications, is the usually high computational load required, which restricts its use for on-line control. This paper proposes the use of a stochastic search algorithm, known as particle swarm, as an optimisation tool for an on-line predictive control of a custom made thermodynamic system. Preliminary results are presented

Greenhouse air temperature modelling

This paper describes two implementation approaches for modelling the air temperature of an automated greenhouse located in the campus of the University of Trás-os- Montes e Alto Douro. Linear models, based in the discretization of the heat transfer physical laws, and non-linear neural networks models are used. These models are describes as functions of the outside climate and control actions performed for heating and cooling. Results are presented to illustrate the performance of each model in the simulation and prediction of the greenhouse air temperature. The data used to compute the simulation models was collected with a PC-based acquisition and control system using a sampling time interval of 1 minute.The authors appreciate the support of the Portuguese Foundation for Science and Technology (FCT) through the project MGS/ 33906/2000

On-line control using the particle swarm optimisation algorithm

In the last two decades, evolutionary based algorithms have proved to be an important tool in solving optimisation problems in many disciplinary areas, namely in control system design. However one of its limitations for some type of applications is the usually high computational load required, which restricts its use for on-line control. This paper proposes the use of a stochastic search algorithm, known as particle swarm, as an optimisation tool for an on-line model predictive control of a custom made laboratory thermodynamic system. Preliminary results are presented

The VMC survey III : Mass-loss rates and luminosities of LMC AGB stars

Context. Asymptotic giant branch (AGB) stars are major contributors to both the chemical enrichment of the interstellar medium and the integrated light of galaxies. Despite its importance, the AGB is one of the least understood phases of stellar evolution. The main difficulties associated with detailed modelling of the AGB are related to the mass-loss process and the 3rd dredge-up efficiency Aims. We provide direct measures of mass-loss rates and luminosities for a complete sample of AGB stars in the Large Magellanic Cloud, disentangling the C- and O-rich stellar populations. Methods. Dust radiative transfer models are presented for all 374 AGB stars candidates in one of the fields observed by the new VISTA survey of the Magellanic Clouds (VMC). Mass-loss rates, luminosities and a classification of C-and O-rich stars are derived by fitting the models to the spectral energy distribution (SED) obtained by combining VMC data with existing optical, near-, and mid-infrared photometry. Results. The classification technique is reliable at a level of - at worst -75% and significantly better for the reddest dusty stars. We classified none of the stars with a relevant mass-loss rate as O-rich, and we can exclude the presence of more than one dusty O-rich star at a similar to 94% level. The bolometric luminosity function we obtained is fully consistent with most of the literature data on the LMC and with the prediction of theoretical models, with a peak of the C-star distribution at M-bol similar or equal to -4.8 mag and no stars brighter than the classical AGB tip, at M-bol = -7.1 mag. Conclusions. This exploratory study shows that our method provides reliable mass-loss rates, luminosities and chemical classifications for all AGB stars. These results offer already important constraints to AGB evolutionary models. Most of our conclusions, especially for the rarer dust-enshrouded extreme AGB stars, are however strongly limited by the relatively small area covered by our study. Forthcoming VMC observations will easily remove this limitation.Peer reviewe

Automation and control of the SORTEGEL wastewater plant

Food Processing Industries produce large amounts of wastewater with high environmental impact. Due to the high content of suspended matter and inadequate pH value of the wastewater, national laws prohibit direct discharges of the influent to the environment. This work describes the design and operation of a wastewater treatment plant installed in the Sortegel food-processing company located in Sortes, Portugal. This industry uses the water collected from groundwater wells to process raw materials and to wash the equipments, being the volume of wastewater produced season dependent (80 to 300m3/day). Results show that the implemented wastewater treatment plant and the automation solutions generate treated effluents that comply with the Portuguese legislation

A small universe after all?

The cosmic microwave background radiation allows us to measure both the geometry and topology of the universe. It has been argued that the COBE-DMR data already rule out models that are multiply connected on scales smaller than the particle horizon. Here we show the opposite is true: compact (small) hyperbolic universes are favoured over their infinite counterparts. For a density parameter of Omega_o=0.3, the compact models are a better fit to COBE-DMR (relative likelihood ~20) and the large-scale structure data (sigma_8 increases by ~25%).Comment: 4 pages, RevTeX, 7 Figure

The spectral action and cosmic topology

The spectral action functional, considered as a model of gravity coupled to matter, provides, in its non-perturbative form, a slow-roll potential for inflation, whose form and corresponding slow-roll parameters can be sensitive to the underlying cosmic topology. We explicitly compute the non-perturbative spectral action for some of the main candidates for cosmic topologies, namely the quaternionic space, the Poincare' dodecahedral space, and the flat tori. We compute the corresponding slow-roll parameters and see we check that the resulting inflation model behaves in the same way as for a simply-connected spherical topology in the case of the quaternionic space and the Poincare' homology sphere, while it behaves differently in the case of the flat tori. We add an appendix with a discussion of the case of lens spaces.Comment: 55 pages, LaTe

Bone Flap Management In Neurosurgery

Bone flap removal procedure is growing in frequency in neurosurgical practice. Decompressive craniotomy has gained more scientifical evidences of its therapeutical value in post-traumatic brain swelling, in cerebrovascular diseases and in brain edema non - responding to clinical treatment after elective surgeries. Bone flap destination after craniotomy has many possible fates. We present a literature review of bone flap management in neurosurgical practice: technical preservation of bone flaps (under the scalp, in the abdominal wall, frozen), when to remove the bone flap and what to do when it is dropped during the craniotomy or is infected.172133137Movassaghi, K., Ver Halen, J., Ganchi, P., Amin-Hanjani, S., Mesa, J., Yaremchuk, M.J., Cranioplasty with subcutaneously preserved autologous bone grafts (2006) Plast Reconstr Surg, 117 (1), pp. 202-206Hauptli, J., Segantini, P., New tissue preservation method for bone flaps following decompressive craniotomy (1980) Helv Chir Acta, 47 (1-2), pp. 121-124Tybor, K., Fortuniak, J., Komunski, P., Papiez, T., Andrzejak, S., Jaskólski, D., Supplementation of cranial defects by an autologous bone flap stored in the abdominal wall (2005) Neurol Neurochir Pol, 39 (3), pp. 220-224Josan, V.A., Sgouros, S., Walsh, A.R., Dover, M.S., Nishikawa, H., Hockley, A.D., Cranioplasty in children (2005) Childs Nerv Syst, 21 (3), pp. 200-204Flannery, T., McConnell, R.S., Cranioplasty: Why throw the bone flap out? (2001) Br J Neurosurg, 15 (6), pp. 518-520Krishnan, P., Bhattacharyya, A.K., Sil, K., De, R., Bone flap preservation after decompressive craniectomy - experience with 55 cases (2006) Neurol India, 54 (3), pp. 291-292Korfali, E., Aksoy, K., Preservation of craniotomy bone flaps under the scalp (1988) Surg Neurol, 30 (4), pp. 269-272Goel, A., Deogaonkar, M., Subgaleal preservation of calvarial flaps (1995) Surg Neurol, 44 (2), pp. 181-182. , Aug;, discussion 182-3Pasaoglu, A., Kurtsoy, A., Koc, R.K., Kontas, O., Akdemir, H., Öktem, I.S., Cranioplasty with bone flaps preserved under the scalp (1996) Neurosurg Rev, 19 (3), pp. 153-156Iwama, T., Yamada, J., Imai, S., Shinoda, J., Funakoshi, T., Sakai, N., The use of frozen autogenous bone flaps in delayed cranioplasty revisited (2003) Neurosurgery, 52 (3), pp. 591-596Winkler, P.A., Stummer, W., Linke, R., Krishnan, K.G., Tatsch, K., The influence of cranioplasty on postural blood flow regulation, cerebrovascular reserve capacity, and cerebral glucose metabolism (2000) Neurosurg Focus, 8 (1), pp. e9Matsuno, A., Tanaka, H., Iwamuro, H., Takanashi, S., Miyawaki, S., Nakashima, M., Analyses of the factors influencing bone graft infection after delayed cranioplasty (2006) Acta Neurochir (Wien), 148 (5), pp. 535-540Yacubian-Fernandes, A., Laronga, P.R., Coelho, R.A., Ducati, L.G., Silva, M.V., Prototyping as an alternative to cranioplasty using methylmethacrylate: Technical, 62 (3 B), pp. 865-868. , note. Arq Neuropsiquiatr 2004;Chiarini, L., Figurelli, S., Pollastri, G., Torcia, E., Ferrari, F., Albanese, M., Cranioplasty using acrylic material: A new technical procedure (2004) J Craniomaxillofac Surg, 32 (1), pp. 5-9Korinek, A.M., Risk factors for neurosurgical site infections after craniotomy: A prospective multicenter study of 2944 patients. The French Study Group of Neurosurgical Infections, the SEHP, and the C-CLIN Paris-Nord. Service Epidemiologie Hygiene et Prevention (1997) Neurosurgery, 41 (5), pp. 1073-1079Bruce, J.N., Bruce, S.S., Preservation of bone flaps in patients with postcraniotomy infections (2003) J Neurosurg, 98 (6), pp. 1203-1207Auguste, K.I., McDermott, M.W., Salvage of infected craniotomy bone flaps with the wash-in, wash-out indwelling antibiotic irrigation system. Technical note and case series of 12 patients (2006) J Neurosurg, 105 (4), pp. 640-644Jankowitz, B.T., Kondziolka, D.S., When the bone flap hits the floor (2006) Neurosurgery, 59 (3), pp. 585-59