Evaluation of follicular lymphoid depletion in the Bursa of Fabricius: an alternative methodology using digital image analysis and artificial neural networks

Fifty Bursa of Fabricius (BF) were examined by conventional optical microscopy and digital images were acquired and processed using Matlab® 6.5 software. The Artificial Neuronal Network (ANN) was generated using Neuroshell® Classifier software and the optical and digital data were compared. The ANN was able to make a comparable classification of digital and optical scores. The use of ANN was able to classify correctly the majority of the follicles, reaching sensibility and specificity of 89% and 96%, respectively. When the follicles were scored and grouped in a binary fashion the sensibility increased to 90% and obtained the maximum value for the specificity of 92%. These results demonstrate that the use of digital image analysis and ANN is a useful tool for the pathological classification of the BF lymphoid depletion. In addition it provides objective results that allow measuring the dimension of the error in the diagnosis and classification therefore making comparison between databases feasible.

Pumping system optimization tool

Pumping systems account for over 20 % of all electricity consumption in European industry. Optimization and correct design of such systems is important and there is a reasonable amount of unrealized energy saving potential in old pumping systems. The energy efficiency and therefore also the energy consumption of a pumping system heavily depends on the correct dimensioning and selection of devices. In this work, a graphical optimization tool for pumping systems is developed in Matlab programming language. The tool selects optimal pump, electrical motor and frequency converter for existing pumping process and calculates the life cycle costs of the whole system. The tool could be used as an aid when choosing the machinery and to analyze the energy consumption of existing systems. Results given by the tool are compared to the results of laboratory tests. The selection of pump and motor works reasonably well, but the frequency converter selection still needs development

Heat transfer inside internal combustion engine: modelling and comparison with experimental data

The paper is devoted to study specific aspects of heat transfer in the combustion chamber of compression ignited reciprocating internal combustion engines and possibility to directly measure the heat flux by means of Gradient Heat Flux Sensors (GHFS). A one – dimensional single zone model proposed by Kyung Tae Yun et al. and implemented with the aid of Matlab, was used to obtain approximate picture of heat flux behavior in the combustion chamber with relation to the crank angle. The model’s numerical output was compared to the experimental results. The experiment was accomplished by A. Mityakov at four stroke diesel engine Indenor XL4D. Local heat fluxes on the surface of cylinder head were measured with fast – response, high – sensitive GHFS. The comparison of numerical data with experimental results has revealed a small deviation in obtained heat flux values throughout the cycle and different behavior of heat flux curve after Top Dead Center.

Simulation of Active Control Using Fuzzy Logic Applied to a Pulse Combustor

This work analyzes an active fuzzy logic control system in a Rijke type pulse combustor. During the system development, a study of the existing types of control for pulse combustion was carried out and a simulation model was implemented to be used with the package Matlab and Simulink. Blocks which were not available in the simulator library were developed. A fuzzy controller was developed and its membership functions and inference rules were established. The obtained simulation showed that fuzzy logic is viable in the control of combustion instabilities. The obtained results indicated that the control system responded to pulses in an efficient and desirable way. It was verified that the system needed approximately 0.2 s to increase the tube internal pressure from 30 to 90 mbar, with an assumed total delay of 2 ms. The effects of delay variation were studied. Convergence was always obtained and general performance was not affected by the delay. The controller sends a pressure signal in phase with the Rijke tube internal pressure signal, through the speakers, when an increase the oscillations pressure amplitude is desired. On the other hand, when a decrease of the tube internal pressure amplitude is desired, the controller sends a signal 180º out of phase.

Performance evaluation of 3D computer vision techniques

This work presents the implementation and comparison of three different techniques of three-dimensional computer vision as follows: • Stereo vision - correlation between two 2D images • Sensorial fusion - use of different sensors: camera 2D + ultrasound sensor (1D); • Structured light The computer vision techniques herein presented took into consideration the following characteristics: • Computational effort ( elapsed time for obtain the 3D information); • Influence of environmental conditions (noise due to a non uniform lighting, overlighting and shades); • The cost of the infrastructure for each technique; • Analysis of uncertainties, precision and accuracy. The option of using the Matlab software, version 5.1, for algorithm implementation of the three techniques was due to the simplicity of their commands, programming and debugging. Besides, this software is well known and used by the academic community, allowing the results of this work to be obtained and verified. Examples of three-dimensional vision applied to robotic assembling tasks ("pick-and-place") are presented.

Kemikaalikiertopolttoon perustuvan höyryvoimalaitoksen mallintaminen IPSEpro:lla

Kandidaatintyön tavoitteena on suunnitella IPSEpro-ohjelmistolla kemikaalikiertopolttoa hyödyntävä höyryvoimalaitos. Kandidaatintyössä tutustutaan kemikaalikiertopolton pääperiaatteisiin ja etuihin hiilidioksidin talteenotossa. IPSEpromallin alkuarvot lasketaan Matlab-pohjaisella 0-D mallilla. IPSEpro-ohjelmistoa esitellään. IPSEpro:lla suunniteltu voimalaitos esitetään ja sitä verrataan kilpaileviin hiilidioksidin talteenottotekniikoihin. Kemikaalikiertopolttoon perustuva höyryvoimalaitos on kilpailukykyinen olemassa olevien teknologioiden kanssa polttoaineen ollessa maakaasua. Kiinteisiin polttoaineisiin siirryttäessä on suoritettava jatkotarkasteluita.

Lujasta teräksestä valmistetun palkin poikkileikkauksen optimointi

Parin viime vuosikymmenen aikana on kehitetty huomattavasti entistä lujempia teräslaatuja, joiden käyttö ei kuitenkaan ole yleistynyt läheskään samaan tahtiin. Korkeamman hinnan lisäksi yksi merkittävä syy tähän on, että suunnittelijoilla ei usein ole riittäviä tietoja siitä, millaisissa tilanteissa lujemman teräslaadun käytöstä on merkittävää hyötyä. Tilannetta ei myöskään helpota se, että käytössä olevat standardit eivät tarjoa lainkaan ohjeistusta kaikkein lujimpien, myötörajaltaan yli 700MPa terästen käyttöön ja mitoitukseen. Tässä työssä pyritään tarjoamaan suunnittelijalle ohjeita ja nyrkkisääntöjä sopivan lujuusluokan ja profiilin valintaan sekä yleisesti lujempien teräslaatujen käyttöön. Lujemman teräslaadun käytöllä voidaan keventää suunniteltavaa rakennetta ja saada aikaan huomattavia painonsäästöjä. Usein ongelmaksi nousevat kuitenkin stabiiliuskriteerit, sillä teräksen lommahduskestävyys määräytyy suuresti sen lujuusluokasta siten, että mitä lujempaa teräs on, sitä helpommin se lommahtaa. Kun tämä yhdistetään siihen, että lujempaa terästä käytettäessä rakenteesta tulee optimoituna muutenkin pienempi ja kevyempi, kasvaa näiden kahden asian yhteisvaikutuksena kantokyvyn mukaan mitoitetun rakenteen taipuma korkeampiin lujuusluokkiin edetessä hyvin nopeasti sallittujen rajojen yli. Työssä etsitään siksi keinoja sopivan kompromissin löytämiseksi lujuuden ja jäykkyyden välille. Koska muotoilulla ja poikkileikkauksella on suuri merkitys sekä taipuman että stabiliteetin kannalta, tutkitaan erilaisia poikkileikkausvaihtoehtoja ja etsitään optimaalista poikkileikkausta taivutuspalkille matemaattisen optimointimallin avulla. Kun eri poikkileikkausvaihtoehdot on käsitelty ja optimoitu taivutuksen suhteen, tutkitaan poikkileikkauksia myös muissa kuormitustapauksissa. Huomattavan raskaan laskentatyön takia apuna käytetään Matlab-ohjelmistoa itse optimointiin ja Femap-ohjelmaa muiden kuormitustapausten tutkimiseen ja tulosten verifioitiin.

Seulonnan erotustehokkuuden määrittäminen - tarkastelussa Reichertin kartioseula

Seulonta on vanha ja teollisuudessa yleisesti käytetty erotusmenetelmä. Huolimat-ta yksinkertaisesta prosessista seulontaa ilmiönä on tutkittu vähän. Prosessin yk-sinkertaisuus on voinut osaltaan vaikuttaa tutkijoiden mielenkiintoon aihetta koh-taan. Tutkimuksen vähyys näkyy etenkin painovoimaiseen seulontaan liittyvän kirjallisuuden vähyytenä. Kirjallisuusosassa käsitellään seulonnan taustaa ja märkä- sekä kuivaseulontaa. Lisäksi määritetään seulontaan vaikuttavat tekijät ja kar-toitetaan seulontaan liittyvää matematiikkaa. Työn kokeellisessa osassa tutkitaan Reichertin kartioseulan erotustehokkuutta 10, 12,5 ja 15 asteen kallistuskulmissa. Tutkimukset tehdään ideaalisille pallomaisille lasihelmille. Mittaustulosten avulla tutkitaan myös partikkelien liikettä seulapin-nalla ja syötetyn massan vaikutusta erotustehokkuuteen. Kokeellisia mittaustulok-sia käytetään MATLAB-mallinnuksessa, jonka avulla optimoidaan kartioseulan kallistuskulmaa ja massapanosta suhteessa erotustehokkuuteen. Tutkimuksen kannalta olennaisia kysymyksiä ovat: ”Onko painovoimaan perustuva erottelu seuloilla riittävä takaamaan hyvän erotustehokkuuden?” ja ”Mikä on seulan ero-tustehokkuuden kannalta optimaalinen kallistuskulma ja syötettävä massa?” Reichertin kartioseulan etuja ovat sen energiatehokkuus ja yksinkertainen helposti säädettävä prosessi. Koemittauksista havaitaan, että erotustehokkuus vastaa opti-moinnin tuloksia. Seulan liian pieni kallistuskulma ja suuri massapanos pienentävät seulan erotustehokkuutta. Lisätutkimuksia tarvitaan eri kallistuskulmilla ja materiaaleilla, jotta tuloksia voidaan verrata todellisiin seulontaprosesseihin.

Lämmön johtuminen kattilan membraaniseinässä

Tässä työssä tarkastellaan voimalaitoskattilan membraaniseinämän lämmönsiirtoa erityisesti johtumisen osalta. Osana tätä työtä tehtiin MATLAB-ohjelmalle skriptikokoelma, jolla voidaan mallintaa ja laskea halutuilla lähtöarvoilla membraaniseinän läpi johtuva lämpöteho sekä seinämän lämpövastus. Samalla saadaan selville rakenteen lämpötilajakauma, jota voidaan käyttää hyödyksi edistyneemmässä mallinnuksessa. Työn alkuosassa tehdään katsaus lämmönsiirron teoriaan ja voimalaitoskattiloihin. Tämän jälkeen esitellään mallinnustyökalun toiminta ja laskennan matemaattinen pohja. Lopuksi tarkastellaan laskentatyökalulla saatuja tuloksia ennalta määritetyissä laskentatapauksissa. Lopulliset tulokset ovat työn liitteissä.

Akuston mitoitus kulutusjouston ja varavoiman näkökulmasta

Tutkimuksen tarkoituksena on selvittää, kuinka paljon vuoden aikainen huippukuorma pienenisi ja minkälaisissa sähkönkäyttökohteissa sähköenergialähteiden käytöllä saavutetaan suurin hyöty. Tarkastelun suorittamiseksi on muodostettu laskentatyökalu Matlab® ohjelmalla, jonka avulla voidaan tarkastella useita kohteita ja muuttaa tarvittaessa tarkastelu parametreja. Tarkastelun kohteina on kolmen tyyppisiä sähkönkäyttö kohteita. Tarkasteltavat kohteet ovat suora-, varaava- tai osittain varaava sähkölämmitys kohteita, joiden sähkönkäyttö eroaa toisistaan. Tutkimuksessa selviää, että suurin hyöty saavutetaan osittain varaavissa ja varaavissa sähkölämmitys kohteissa. Kuitenkin tämän hetken sähköenergialähteiden hintataso on liian suuri, jotta niiden käyttö huippukuorman pudottamisessa olisi kannattavaa.

Forecasting of wind speeds and directions with artificial neural networks

In this master’s thesis, wind speeds and directions were modeled with the aim of developing suitable models for hourly, daily, weekly and monthly forecasting. Artificial Neural Networks implemented in MATLAB software were used to perform the forecasts. Three main types of artificial neural network were built, namely: Feed forward neural networks, Jordan Elman neural networks and Cascade forward neural networks. Four sub models of each of these neural networks were also built, corresponding to the four forecast horizons, for both wind speeds and directions. A single neural network topology was used for each of the forecast horizons, regardless of the model type. All the models were then trained with real data of wind speeds and directions collected over a period of two years in the municipal region of Puumala in Finland. Only 70% of the data was used for training, validation and testing of the models, while the second last 15% of the data was presented to the trained models for verification. The model outputs were then compared to the last 15% of the original data, by measuring the mean square errors and sum square errors between them. Based on the results, the feed forward networks returned the lowest generalization errors for hourly, weekly and monthly forecasts of wind speeds; Jordan Elman networks returned the lowest errors when used for forecasting of daily wind speeds. Cascade forward networks gave the lowest errors when used for forecasting daily, weekly and monthly wind directions; Jordan Elman networks returned the lowest errors when used for hourly forecasting. The errors were relatively low during training of the models, but shot up upon simulation with new inputs. In addition, a combination of hyperbolic tangent transfer functions for both hidden and output layers returned better results compared to other combinations of transfer functions. In general, wind speeds were more predictable as compared to wind directions, opening up opportunities for further research into building better models for wind direction forecasting.

Adaptive control of Hydraulic Drive

Adaptive control systems are one of the most significant research directions of modern control theory. It is well known that every mechanical appliance’s behavior noticeably depends on environmental changes, functioning-mode parameter changes and changes in technical characteristics of internal functional devices. An adaptive controller involved in control process allows reducing an influence of such changes. In spite of this such type of control methods is applied seldom due to specifics of a controller designing. The work presented in this paper shows the design process of the adaptive controller built by Lyapunov’s function method for the Hydraulic Drive. The calculation needed and the modeling were conducting with MATLAB® software including Simulink® and Symbolic Math Toolbox™ etc. In the work there was applied the Jacobi matrix linearization of the object’s mathematical model and derivation of the suitable reference models based on Newton’s characteristic polynomial. The intelligent adaptive to nonlinearities algorithm for solving Lyapunov’s equation was developed. Developed algorithm works properly but considered plant is not met requirement of functioning with. The results showed confirmation that adaptive systems application significantly increases possibilities in use devices and might be used for correction a system’s behavior dynamics.

LVDC power distribution system: computational modelling

In the doctoral dissertation, low-voltage direct current (LVDC) distribution system stability, supply security and power quality are evaluated by computational modelling and measurements on an LVDC research platform. Computational models for the LVDC network analysis are developed. Time-domain simulation models are implemented in the time-domain simulation environment PSCAD/EMTDC. The PSCAD/EMTDC models of the LVDC network are applied to the transient behaviour and power quality studies. The LVDC network power loss model is developed in a MATLAB environment and is capable of fast estimation of the network and component power losses. The model integrates analytical equations that describe the power loss mechanism of the network components with power flow calculations. For an LVDC network research platform, a monitoring and control software solution is developed. The solution is used to deliver measurement data for verification of the developed models and analysis of the modelling results. In the work, the power loss mechanism of the LVDC network components and its main dependencies are described. Energy loss distribution of the LVDC network components is presented. Power quality measurements and current spectra are provided and harmonic pollution on the DC network is analysed. The transient behaviour of the network is verified through time-domain simulations. DC capacitor guidelines for an LVDC power distribution network are introduced. The power loss analysis results show that one of the main optimisation targets for an LVDC power distribution network should be reduction of the no-load losses and efficiency improvement of converters at partial loads. Low-frequency spectra of the network voltages and currents are shown, and harmonic propagation is analysed. Power quality in the LVDC network point of common coupling (PCC) is discussed. Power quality standard requirements are shown to be met by the LVDC network. The network behaviour during transients is analysed by time-domain simulations. The network is shown to be transient stable during large-scale disturbances. Measurement results on the LVDC research platform proving this are presented in the work.

Comparison study of two competing models of an all mechanical power transmission system

A comparison between two competing models of an all mechanical power transmission system is studied by using Dymola –software as the simulation tool. This tool is compared with Matlab/ Simulink –software by using functionality, user-friendliness and price as comparison criteria. In this research we assume that the torque is balanceable and transmission ratios are calculated. Using kinematic connection sketches of the two transmission models, simulation models are built into the Dymola simulation environment. Models of transmission systems are modified according to simulation results to achieve a continuous variable transmission ratio. Simulation results are compared between the two transmission systems. The main features of Dymola and MATLAB/ Simulink are compared. Advantages and disadvantages of the two softwares are analyzed and compared.

Intelligent mapping of stresses in a hydraulic crane

Continuous loading and unloading can cause breakdown of cranes. In seeking solution to this problem, the use of an intelligent control system for improving the fatigue life of cranes in the control of mechatronics has been under study since 1994. This research focuses on the use of neural networks as possibilities of developing algorithm to map stresses on a crane. The intelligent algorithm was designed to be a part of the system of a crane, the design process started with solid works, ANSYS and co-simulation using MSc Adams software which was incorporated in MATLAB-Simulink and finally MATLAB neural network (NN) for the optimization process. The flexibility of the boom accounted for the accuracy of the maximum stress results in the ADAMS model. The flexibility created in ANSYS produced more accurate results compared to the flexibility model in ADAMS/View using discrete link. The compatibility between.ADAMS and ANSYS softwares was paramount in the efficiency and the accuracy of the results. Von Mises stresses analysis was more suitable for this thesis work because the hydraulic boom was made from construction steel FE-510 of steel grade S355 with yield strength of 355MPa. Von Mises theory was good for further analysis due to ductility of the material and the repeated tensile and shear loading. Neural network predictions for the maximum stresses were then compared with the co-simulation results for accuracy, and the comparison showed that the results obtained from neural network model were sufficiently accurate in predicting the maximum stresses on the boom than co-simulation.