Power-line-communication-based data transmission concept for an LVDC electricity distribution network – Analysis and implementation

Communications play a key role in modern smart grids. New functionalities that make the grids ‘smart’ require the communication network to function properly. Data transmission between intelligent electric devices (IEDs) in the rectifier and the customer-end inverters (CEIs) used for power conversion is also required in the smart grid concept of the low-voltage direct current (LVDC) distribution network. Smart grid applications, such as smart metering, demand side management (DSM), and grid protection applied with communications are all installed in the LVDC system. Thus, besides remote connection to the databases of the grid operators, a local communication network in the LVDC network is needed. One solution applied to implement the communication medium in power distribution grids is power line communication (PLC). There are power cables in the distribution grids, and hence, they may be applied as a communication channel for the distribution-level data. This doctoral thesis proposes an IP-based high-frequency (HF) band PLC data transmission concept for the LVDC network. A general method to implement the Ethernet-based PLC concept between the public distribution rectifier and the customerend inverters in the LVDC grid is introduced. Low-voltage cables are studied as the communication channel in the frequency band of 100 kHz–30 MHz. The communication channel characteristics and the noise in the channel are described. All individual components in the channel are presented in detail, and a channel model, comprising models for each channel component is developed and verified by measurements. The channel noise is also studied by measurements. Theoretical signalto- noise ratio (SNR) and channel capacity analyses and practical data transmission tests are carried out to evaluate the applicability of the PLC concept against the requirements set by the smart grid applications in the LVDC system. The main results concerning the applicability of the PLC concept and its limitations are presented, and suggestion for future research proposed.

Analyses of the usefulness of Software Defined Storage Solutions for Web-based Digital Preservation Applications

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

An optically coupled power stimulus isolation unit with high voltage and fast rise time output

Recent technological developments have created new devices that could improve and simplify the construction of stimulus isolators. HEXFET transistors can switch large currents and hundreds of volts in nanoseconds. The newer opto-isolators can give a pulse rise time of a few nanoseconds, with output compatible with MOSFET devices, in which delays are reduced to nanoseconds. Integrated DC/DC converters are now available. Using these new resources we developed a new electrical stimulus isolator circuit with selectable constant-current and constant-voltage modes, which are precise and easy to construct. The circuit works like a regulated power supply in both modes with output switched to zero or to free mode through an opto-isolator device. The isolator analyses showed good practical performance. The output to ground resistance was 1011 ohms and capacitance 35 picofarads. The rise time and fall time were identical (5 µs) and constant. The selectable voltage or current output mode made it very convenient to use. The current mode, with higher output resistance values in low current ranges, permits intracellular stimulation even with tip resistances close to 100 megaohms. The high compliance of 200 V guarantees the value of the current stimulus. The very low output resistance in the voltage mode made the device highly suitable for extracellular stimulation with low impedance electrodes. Most importantly, these characteristics were achieved with a circuit that was easy to build and modify and assembled with components available in Brazil.

Tandem-MAG-welding of high strength steels for shipbuilding applications

Tämän työn tavoitteena oli hitsata tandem MAG –laitteistolla 25 mm paksua Ruukin E500 TMCP terästä. Työssä oli tarkoituksena vähentää railotilavuutta mahdollisimman paljon sekä suorittaa testihitsaukset 0.8 kJ/mm sekä 2.5 kJ/mm lämmöntuonneilla. Teoriaosuudessa käsiteltiin Tandem MAG-hitsaukseen, sen tuottavuuteen ja laatukysymyksiin liittyviä asioita sekä siinä perehdyttiin suurlujuusteräksien käyttöön hitsauksessa sekä laivanrakennuksessa. Kokeellisessa osuudessa perehdyttiin hitsauksessa huomattuihin etuihin, ongelmiin sekä ongelmien ratkaisumahdollisuuksiin. Hitsausliitoksen mekaaniset ominaisuudet tutkittiin rikkomattomin sekä rikkovin menetelmin. Alustavat hitsausohjeet luotiin kummallekin lämmöntuonnille. Testaukset aloitettiin 30 º railokulmalla pienentäen kulmaa mahdollisuuksien mukaan. Testauksissa ei saatu hitsattua onnistuneesti alle 30 º railokulmalla. Hitsaustestien aikana huomattiin magneettisen puhalluksen vaikutus hitsaustapahtumaan. Kaasunvirtausnopeuden tuli olla tietyn suuruinen jotta palkokerrokset onnistuivat ilman huokoisuusongelmaa. Pienemmällä lämmöntuonnilla hitsattaessa kaasunvirtausnopeudet olivat tärkeämpiä hitsatessa ylempiä palkokerroksia. Kääntämällä hitsauspoltinta sivuttaissuunnassa 7-10 astetta auttoi ehkäisemään reunahaavan syntymistä. Rikkovista menetelmistä testitulokset olivat hyväksyttyjä kaikkien muiden paitsi päittäishitsin sivutaivutuskokeen osalta.

Local Binary Patterns in Focal-Plane Processing. Analysis and Applications

Feature extraction is the part of pattern recognition, where the sensor data is transformed into a more suitable form for the machine to interpret. The purpose of this step is also to reduce the amount of information passed to the next stages of the system, and to preserve the essential information in the view of discriminating the data into different classes. For instance, in the case of image analysis the actual image intensities are vulnerable to various environmental effects, such as lighting changes and the feature extraction can be used as means for detecting features, which are invariant to certain types of illumination changes. Finally, classification tries to make decisions based on the previously transformed data. The main focus of this thesis is on developing new methods for the embedded feature extraction based on local non-parametric image descriptors. Also, feature analysis is carried out for the selected image features. Low-level Local Binary Pattern (LBP) based features are in a main role in the analysis. In the embedded domain, the pattern recognition system must usually meet strict performance constraints, such as high speed, compact size and low power consumption. The characteristics of the final system can be seen as a trade-off between these metrics, which is largely affected by the decisions made during the implementation phase. The implementation alternatives of the LBP based feature extraction are explored in the embedded domain in the context of focal-plane vision processors. In particular, the thesis demonstrates the LBP extraction with MIPA4k massively parallel focal-plane processor IC. Also higher level processing is incorporated to this framework, by means of a framework for implementing a single chip face recognition system. Furthermore, a new method for determining optical flow based on LBPs, designed in particular to the embedded domain is presented. Inspired by some of the principles observed through the feature analysis of the Local Binary Patterns, an extension to the well known non-parametric rank transform is proposed, and its performance is evaluated in face recognition experiments with a standard dataset. Finally, an a priori model where the LBPs are seen as combinations of n-tuples is also presented

Integrated energy storage tank for large scale power-to-gas applications

The global interest towards renewable energy production such as wind and solar energy is increasing, which in turn calls for new energy storage concepts due to the larger share of intermittent energy production. Power-to-gas solutions can be utilized to convert surplus electricity to chemical energy which can be stored for extended periods of time. The energy storage concept explored in this thesis is an integrated energy storage tank connected to an oxy-fuel combustion plant. Using this approach, flue gases from the plant could be fed directly into the storage tank and later converted into synthetic natural gas by utilizing electrolysis-methanation route. This work utilizes computational fluid dynamics to model the desublimation of carbon dioxide inside a storage tank containing cryogenic liquid, such as liquefied natural gas. Numerical modelling enables the evaluation of the transient flow patterns caused by the desublimation, as well as general fluid behaviour inside the tank. Based on simulations the stability of the cryogenic storage and the magnitude of the key parameters can be evaluated.

The effect of an aerobic training program on the electrical remodeling of the heart: high-frequency components of the signal-averaged electrocardiogram are predictors of the maximal aerobic power

Increased heart rate variability (HRV) and high-frequency content of the terminal region of the ventricular activation of signal-averaged ECG (SAECG) have been reported in athletes. The present study investigates HRV and SAECG parameters as predictors of maximal aerobic power (VO2max) in athletes. HRV, SAECG and VO2max were determined in 18 high-performance long-distance (25 ± 6 years; 17 males) runners 24 h after a training session. Clinical visits, ECG and VO2max determination were scheduled for all athletes during thew training period. A group of 18 untrained healthy volunteers matched for age, gender, and body surface area was included as controls. SAECG was acquired in the resting supine position for 15 min and processed to extract average RR interval (Mean-RR) and root mean squared standard deviation (RMSSD) of the difference of two consecutive normal RR intervals. SAECG variables analyzed in the vector magnitude with 40-250 Hz band-pass bi-directional filtering were: total and 40-µV terminal (LAS40) duration of ventricular activation, RMS voltage of total (RMST) and of the 40-ms terminal region of ventricular activation. Linear and multivariate stepwise logistic regressions oriented by inter-group comparisons were adjusted in significant variables in order to predict VO2max, with a P < 0.05 considered to be significant. VO2max correlated significantly (P < 0.05) with RMST (r = 0.77), Mean-RR (r = 0.62), RMSSD (r = 0.47), and LAS40 (r = -0.39). RMST was the independent predictor of VO2max. In athletes, HRV and high-frequency components of the SAECG correlate with VO2max and the high-frequency content of SAECG is an independent predictor of VO2max.

Power Consumption Measurement and Scenario Based Energy Model in Wearable Computing Applications

The power is still today an issue in wearable computing applications. The aim of the present paper is to raise awareness of the power consumption of wearable computing devices in specific scenarios to be able in the future to design energy efficient wireless sensors for context recognition in wearable computing applications. The approach is based on a hardware study. The objective of this paper is to analyze and compare the total power consumption of three representative wearable computing devices in realistic scenarios such as Display, Speaker, Camera and microphone, Transfer by Wi-Fi, Monitoring outdoor physical activity and Pedometer. A scenario based energy model is also developed. The Samsung Galaxy Nexus I9250 smartphone, the Vuzix M100 Smart Glasses and the SimValley Smartwatch AW-420.RX are the three devices representative of their form factors. The power consumption is measured using PowerTutor, an android energy profiler application with logging option and using unknown parameters so it is adjusted with the USB meter. The result shows that the screen size is the main parameter influencing the power consumption. The power consumption for an identical scenario varies depending on the wearable devices meaning that others components, parameters or processes might impact on the power consumption and further study is needed to explain these variations. This paper also shows that different inputs (touchscreen is more efficient than buttons controls) and outputs (speaker sensor is more efficient than display sensor) impact the energy consumption in different way. This paper gives recommendations to reduce the energy consumption in healthcare wearable computing application using the energy model.

Carbon sources for Power-to-Gas applications in the Finnish energy system

This thesis is done as a part of the NEOCARBON project. The aim of NEOCARBON project is to study a fully renewable energy system utilizing Power-to-Gas or Power-to-Liquid technology for energy storage. Power-to-Gas consists of two main operations: Hydrogen production via electrolysis and methane production via methanation. Methanation requires carbon dioxide and hydrogen as a raw material. This thesis studies the potential carbon dioxide sources within Finland. The different sources are ranked using the cost and energy penalty of the carbon capture, carbon biogenity and compatibility with Power-to-Gas. It can be concluded that in Finland there exists enough CO2 point sources to provide national PtG system with sufficient amounts of carbon. Pulp and paper industry is single largest producer of biogenic CO2 in Finland. It is possible to obtain single unit capable of grid balancing operations and energy transformations via Power-to-Gas and Gas-to-Power by coupling biogas plants with biomethanation and CHP units.

Hardware design of a multiconverter for hybrid vehicle applications

Hybridiajoneuvosovellukset vaativat usein sekä korkea- että matalajännitejärjestelmän. Korkeajännitejärjestelmä sisältää yleensä energiavaraston, joka on joko superkondansaattori tai korkeajänniteakusto, dieselgeneraattorin tai range extenderin ja ajokäytön. Korkeajännitejärjestelmään liitetään usein myös erilaisia apukäyttöjä kuten kompressoreita ja hydraulipumppuja. Matalajännitejärjelmä koostuu yleensä ohjausyksiköistä, ajovaloista, yms. laitteista. Perinteisesti matalajännitejärjestelmää on syötetty dieselmoottorin laturista, mutta korkeajännitejärjestelmien myötä DC/DC-hakkurin käyttäminen korkea- ja matalajännitejärjestelmien välillä on herättänyt kiinnostusta, koska tällöin laturin voisi poistaa ja matalajänniteakustoa pienentää. Tässä työssä kuvatun monilähöisen tehonmuokkaimen invertterisilta soveltuu apukäyttöjen ajamiseen, ja erotettu DC/DC-hakkuri matalajännitejärjestelmän syöttämiseen. Tässä työssä käydään läpi edellä mainitun tehonmuokkaimen suunnittelu, keskittyen eritoten laitteen korkeajänniteosien mitoitukseen ja termiseen suunniteluun. DC/DC-hakkurin osalta perinteisiä piistä valmistettuja IGBT transistoreja vertaillaan piikarbidi MOSFET transistoreihin. Lämpömallilaskujen paikkaansapitävyyttä tutkitaan suorittamalla prototyyppilaitteelle hyötysuhdemittaus, jonka tuloksia verrataan laskettuihin tuloksiin. Lämpömallin parannusmahdollisuuksia käsitellään myös hyötysuhdemittauksen tulosten perusteella.

Real-time monitoring of laser scribing process utilizing high-speed camera

Currently, laser scribing is growing material processing method in the industry. Benefits of laser scribing technology are studied for example for improving an efficiency of solar cells. Due high-quality requirement of the fast scribing process, it is important to monitor the process in real time for detecting possible defects during the process. However, there is a lack of studies of laser scribing real time monitoring. Commonly used monitoring methods developed for other laser processes such a laser welding, are sufficient slow and existed applications cannot be implemented in fast laser scribing monitoring. The aim of this thesis is to find a method for laser scribing monitoring with a high-speed camera and evaluate reliability and performance of the developed monitoring system with experiments. The laser used in experiments is an IPG ytterbium pulsed fiber laser with 20 W maximum average power and Scan head optics used in the laser is Scanlab’s Hurryscan 14 II with an f100 tele-centric lens. The camera was connected to laser scanner using camera adapter to follow the laser process. A powerful fully programmable industrial computer was chosen for executing image processing and analysis. Algorithms for defect analysis, which are based on particle analysis, were developed using LabVIEW system design software. The performance of the algorithms was analyzed by analyzing a non-moving image from the scribing line with resolution 960x20 pixel. As a result, the maximum analysis speed was 560 frames per second. Reliability of the algorithm was evaluated by imaging scribing path with a variable number of defects 2000 mm/s when the laser was turned off and image analysis speed was 430 frames per second. The experiment was successful and as a result, the algorithms detected all defects from the scribing path. The final monitoring experiment was performed during a laser process. However, it was challenging to get active laser illumination work with the laser scanner due physical dimensions of the laser lens and the scanner. For reliable error detection, the illumination system is needed to be replaced.

Efficient estimation using the characteristic function : theory and applications with high frequency data

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Développement de nouveaux sels Binol-imidazoliums : de la catalyse asymétrique aux applications biologiques

Le 1,1'-bi-2-naphtol ou Binol, présentant une chiralité axiale, est un ligand très utilisé en catalyse asymétrique. Au cours des vingt dernières années, le Binol a servi de synthon à l’élaboration de très nombreux ligands permettant la catalyse asymétrique de tous types de réactions, allant de l’hydrogénation, à l’alkylation, en passant par diverses réactions péricycliques. Le grand intérêt pour ce ligand vient de sa versatilité et des nombreuses possibilités de fonctionnalisation qu’il offre, permettant d’altérer ses propriétés catalytiques à volonté, aussi bien en modifiant son caractère électronique, qu’en introduisant des facteurs stériques autour du site catalytique. Parallèlement aux développements de la catalyse par des dérivés de Binol, le domaine des liquides ioniques a connu un intérêt croissant ces dernières années. Les liquides ioniques, sels dont le point de fusion est inférieur à 100°C, cumulent de nombreuses qualités convoitées : faible pression de vapeur, stabilité thermique et chimique et fort pouvoir de solvatation. Dû à ces propriétés, les liquides ioniques ont principalement été étudiés dans l’optique de développer une gamme de solvants recyclables. Alors que les propriétés des liquides ioniques sont facilement modulables en fonction de l’anion et du cation choisi, le concept de liquide ionique à tâche spécifique va plus loin et propose d’introduire directement, sur le cation ou l’anion, un groupement conférant une propriété particulière. En suivant cette approche, plusieurs ligands ioniques ont été rapportés, par simple couplage d’un cation organique à un ligand déjà connu. Étonnamment, le Binol a fait l’objet de très peu de travaux pour l’élaboration de ligands ioniques. Dans cette thèse, nous proposons l’étude d’une famille de composés de type Binol-imidazolium dont les unités Binol et imidazolium sont séparées par un espaceur méthylène. Différents homologues ont été synthétisés en variant le nombre d’unités imidazolium et leur position sur le noyau Binol, la longueur de la chaîne alkyle portée par les unités imidazolium et la nature du contre-anion. Après une étude des propriétés thermiques de ces composés, l’utilisation des Binol-imidazoliums en tant que ligands dans une réaction asymétrique d’éthylation d’aldéhydes aromatique a été étudiée en milieu liquide ionique. La réaction a été conduite en solvant liquide ionique dans le but de recycler aussi bien le ligand Binol-imidazolium que le solvant, en fin de réaction. Cette étude nous a permis de démontrer que la sélectivité de ces ligands ioniques dépend grandement de leur structure. En effet, seuls les Binols fonctionnalisés en positions 6 et 6’ permettent une sélectivité de la réaction d’éthylation. Alors que les dérivés de Binol fonctionnalisés en positions 3 et 3’ ne permettent pas une catalyse énantiosélective, il a déjà été rapporté que ces composés avaient la capacité de complexer des anions. D’autre part, il a déjà été rapporté par notre groupe, que les composés comportant des unités imidazolium pouvaient permettre le transport d’anions à travers des bicouches lipidiques en fonction de leur amphiphilie. Ceci nous a amenés à la deuxième partie de cette thèse qui porte sur les propriétés ionophores des Binols fonctionnalisés en positions 3 et 3’ par des unités imidazoliums. Dans un premier temps, nous nous sommes intéressés à l’étude de la relation structure-activité et au mécanisme de transport de ces composés. Le transport d’anions étant un processus clé dans la biologie cellulaire, l’activité biologique des composés présentant une activité ionophore dans des systèmes modèles (liposomes) a été étudiée par la suite. L’activité antibactérienne des nos composés a été testée sur quatre souches de bactéries. Il s’est avéré que les composés Binol-imidazolium sont actifs uniquement sur les bactéries Gram positives. Finalement, la cytotoxicité des composés présentant une activité antibactérienne a été étudiée sur des cellules humaines.

Apprentissage des réseaux de neurones profonds et applications en traitement automatique de la langue naturelle

En apprentissage automatique, domaine qui consiste à utiliser des données pour apprendre une solution aux problèmes que nous voulons confier à la machine, le modèle des Réseaux de Neurones Artificiels (ANN) est un outil précieux. Il a été inventé voilà maintenant près de soixante ans, et pourtant, il est encore de nos jours le sujet d'une recherche active. Récemment, avec l'apprentissage profond, il a en effet permis d'améliorer l'état de l'art dans de nombreux champs d'applications comme la vision par ordinateur, le traitement de la parole et le traitement des langues naturelles. La quantité toujours grandissante de données disponibles et les améliorations du matériel informatique ont permis de faciliter l'apprentissage de modèles à haute capacité comme les ANNs profonds. Cependant, des difficultés inhérentes à l'entraînement de tels modèles, comme les minima locaux, ont encore un impact important. L'apprentissage profond vise donc à trouver des solutions, en régularisant ou en facilitant l'optimisation. Le pré-entraînnement non-supervisé, ou la technique du ``Dropout'', en sont des exemples. Les deux premiers travaux présentés dans cette thèse suivent cette ligne de recherche. Le premier étudie les problèmes de gradients diminuants/explosants dans les architectures profondes. Il montre que des choix simples, comme la fonction d'activation ou l'initialisation des poids du réseaux, ont une grande influence. Nous proposons l'initialisation normalisée pour faciliter l'apprentissage. Le second se focalise sur le choix de la fonction d'activation et présente le rectifieur, ou unité rectificatrice linéaire. Cette étude a été la première à mettre l'accent sur les fonctions d'activations linéaires par morceaux pour les réseaux de neurones profonds en apprentissage supervisé. Aujourd'hui, ce type de fonction d'activation est une composante essentielle des réseaux de neurones profonds. Les deux derniers travaux présentés se concentrent sur les applications des ANNs en traitement des langues naturelles. Le premier aborde le sujet de l'adaptation de domaine pour l'analyse de sentiment, en utilisant des Auto-Encodeurs Débruitants. Celui-ci est encore l'état de l'art de nos jours. Le second traite de l'apprentissage de données multi-relationnelles avec un modèle à base d'énergie, pouvant être utilisé pour la tâche de désambiguation de sens.

Studies on Chemical Bath Deposited Semiconducting Copper Selenide and Iron Sulfide Thin Films Useful For Photovoltaic Applications

Chemical bath deposition (CBD)is one of the simplest, very convient and probably the cheapest method for thin film preparation. Photovoltaic is the cleanest and the most efficient mode of conversion of energy to electrical power. Silicon is the most popular material in this field. The present study on chemical bath deposited semiconducting copper selenide and iron sulfide thin films useful for photovoltaic applications. Semiconducting thin films prepared by chemical deposition find applications as photo detectors, solar control coatings and solar cells. Copper selenide is a p-type semiconductor that finds application in photovolitics. Several heterojunction systems such as Cu2-xSe/ZnSe (for injection electro luminescence), Cu2Se/AgInSe2 and Cu2Se/Si (for photodiodes), Cu2-xSe/CdS, Cu2-xSe/CdSe, CuxSe/InP and Cu2-xSe/Si for solar cells are reported. A maximum efficiency of 8.3% was achieved for the Cu2-xSe/Si cell, various preparation techniques are used for copper selenide like vacuum evaporation, direct reaction, electrodeposition and CBD. Instability of the as-prepared films was investigation and is accounted as mainly due to deviation from stoichiometry and the formation of iron oxide impurity. A sulphur annealing chamber was designed and fabricated for this work. These samples wee also analysed using optical absorption technique, XPS (X-ray Photoelectron Spectroscopy) and XRD.(X-Ray Diffraction).The pyrite films obtained by CBD technique showed amorphous nature and the electrical studies carried out showed the films to be of high resistive nature. Future work possible in the material of iron pyrite includes sulphur annealing of the non-stochiometric iron pyrite CBD thin films in the absence of atmospheric oxygen