Free OGC standardized WEB services for spatial data

This paper presents an overview and possibilities for the usage of open web services and standardized interfaces for spatial data that are developed and maintained by the OGC (Open Geospatial Consortium). Besides the short overview of various approaches and implementation of web services, this paper focuses on the most frequently applied OpenGIS standard services that are based on the XML meta-language for the exchange of messages and spatial data transfer The concluding remarks outline the main existent and potential application domains of open web services in the field of surveying, with regard to the access to distributed databases and web cartographic presentations

Generatorji delno umetnih podatkov na podlagi samokodirnikov

The goal of the thesis is to alleviate the problem of insufficient data available for data analysis or machine learning. We developed a generator of semi-artificial data based on autoencoders. We implemented dynamic autoencoders without any predefined structure, as we wanted that our solution is general and may therefore be used on any data set. Results showed that autoencoder based generators work better than variational autoencoders. The generators perform best on data sets with a small number of mixed attributes and balanced classes. They perform better if more training instances are available. Results additionally show that grid search significantly improves the performance and that it is possible to predict a good set of parameters for each data set.Glavni cilj naloge je bil olajšati problem pomanjkanja podatkov pri analizi podatkov in v strojnem učenju. Razvili smo generator delno umetnih podatkov na podlagi samokodirnikov. Implementirali smo dinamične samokodirnike brez vnaprej določene strukture, saj smo želeli, da so generatorji uporabni na poljubni učni množici. Rezultati so pokazali, da generatorji na podlagi samokodirnikov delujejo bolje kot variacijski samokodirniki. Naši generatorji najbolje delujejo na podatkovnih množicah z manjšim številom atributov in z uravnoteženimi razredi. Večje število učnih primerov izboljša delovanje generatorjev. Rezultati so tudi pokazali, da z mrežnim iskanjem znatno izboljšamo rezultate in da je možno napovedati dobre parametre glede na karakteristike dane podatkovne množice

Definition and effects of drought

The graduation thesis deals with different definitions and extent of drought around the World, in\ud Europe and Slovenia. Extreme drought occurrences are being analysed according to their duration,\ud cost or number of death causes. The research paper studies monthly temperatures and the amount of\ud monthly precipitation of Ljubljana in 1851-2013 period, measuring drought based on Standard\ud Precipitation Index. These data are foundation to further forecast and spotting the changes being\ud brought to us in the future. Intensity of a drought phenomenon depends on warming of the\ud athmosphere and irregular precipitation. Some possible solutions to drought effects reduction and\ud watercourse and groundwater revitalizing are presented at the end. We can conclude that prevention\ud expenses are in considerable favour of annual damage costs

Autoencoder based generators of semi-artificial data

The goal of the thesis is to alleviate the problem of insufficient data available for data analysis or machine learning. We developed a generator of semi-artificial data based on autoencoders. We implemented dynamic autoencoders without any predefined structure, as we wanted that our solution is general and may therefore be used on any data set. Results showed that autoencoder based generators work better than variational autoencoders. The generators perform best on data sets with a small number of mixed attributes and balanced classes. They perform better if more training instances are available. Results additionally show that grid search significantly improves the performance and that it is possible to predict a good set of parameters for each data set

Impact of a virtual power plant on a medium voltage network

Namen diplomske naloge je predstaviti koncep tvirtualne elektrarne in njen vpliv na obratovanje srednjenapetostnega elektroenergetskega omrežja. V pametnih omrežjih virtualna elektrarna predstavlja del pametnega omrežja, ki je odgovor na spremenjene razmere v omrežju zaradi novonastalih elementov. So posledica sprejetja zavez glede deleža obnovljivih virov v porabi energije, zmanjševanja izpustov CO2 in povečanja energetske učinkovitosti ter razvoju nove tehnologije. V diplomski nalogi predstavljamo rešitev za vzpostavljanje stabilnosti SN omrežja ob izpadu oziroma upadu električne energije. V izbranem omrežju mnogokrat prihaja do izpadov električne energije, zato smo si izbrali vir energije z močjo 1 MVA, v našem primeru dieselski agregat. Priključimo ga na distribucijsko omrežje ob izpadu ali padcu napetosti. Osredotočili smo se na delovanje virtualne elektrarne, predstavili postopek priključitve in dokumentacijo, ki je potrebna, da lahko uporabimo virtualno elektrarno. Kot del, v katerem smo preučili in naredili analizo uporabljenega izvoda, smo preračunali padce napetosti ter obremenitve oziroma pretoke moči na distribucijskem omrežju. V zaključku oziroma kot rešitev opazimo, da je vpliv generatorja na izbran sistem pri različnih obremenitvah (50 % in 100 %) opazen, saj se znižajo padci napetosti. V primeru delovanja je opažen padec delovne moči in stabilizacija napetosti tako v razdelilni transformatorski postaji kot tudi na opazovanem srednjenapetostnem izvodu. Pri polni in polovični obremenitvi srednjenapetostnega izvoda je 30 % znižanje obremenitve celice v razdelilni transformatorski postaji. Vpliv generatorja se kaže tudi pri izgubah, ki so prisotne v srednjenapetostnem izvodu. Izgube se skoraj prepolovijo, vzrok zmanjšanja izgub pa tiči v manjših pretokih moči po omrežju. Vsi ti izračuni so pri najboljših pogojih, ne vemo pa, kako bi se to odražalo v realnosti.The purpose of our thesis is to introduce the concept of virtual power plants and their energy impact on medium electricity grid. When speaking of smart grids, a virtual power plant constitutes a part of a smart grid which is in itself a response to a change in conditions, caused by an unpredicted occurrence. Virtual power plants came to being as a consequence of obligations concerning shares of renewable sources in energy consumption, reduction of CO2 emissions, other improvements in energy efficiency and development of new technology . Our thesis presents a solution in case of a blackout or a failure in power supply. In the grid chosen for our research, power cuts occur frequently, which lead us to choose a power source with an output of 1 MVA. In our case, it was a diesel-powered generator. It is connected to the distribution network upon a partial or total failure in power supply. Focussed on operation of virtual power plants, the paper set about installation and documentation necessary to put the power plant in operation. In the analysis part we have calculated the voltage drops and choke points or current within the distribution network. We come to a conclusion that the generator’s energy impact on the chosen electricity system at different loads (50 % and 100 % load) is significant, since voltage drops are decreased. Regarding operation, we noticed output power decrease and voltage stabilization at the transformer stations, as well as the observed medium voltage outlet. At the full and half load on the medium voltage power outlet, a 30 % load decrease of the transformer station cell is noted. Also notable is generator’s influence on power losses at the mv power outlet. The power losses are reduced to half, the reason for this lying in the lower current throughout the grid. These calculations have been conducted in ideal conditions, but it is uncertain, how these calculations would vary in reality

Localization of electromechanical disturbance in large electric power systems

V tem magistrskem delu smo predstavili širjenje elektromehanske motnje v elektroenergetskem sistemu. Različne topologije omrežja smo modelirali z zbiralkami, na katere so preko tranzientne reaktance priključeni generatorji z vztrajnostjo, zbiralke pa smo med seboj povezali z vodi z reaktanco. Nihajne enačbe generatorjev smo linealizirali v okolici delovnih točk ter ustvarili sistem linearnih diferencialnih enačb prvega reda, ki za vektor spremenljivk stanja in njihove odvode izračuna vrednost v naslednjem ali prejšnjem trenutku. Širjenje motnje in njen odboj na fizičnem robu omrežja sta bila v skladu s pričakovanji. Pri simulaciji v inverznem času se motnja rekonstruira v mestu njenega nastanka, prav tako lokator motnje kot njen izvor poda pravi generator. Pri večanju reaktanc na vodih, ki povezujejo zbiralke, ali vztrajnostnih konstant generatorjev se hitrost širjenja elektromehanske motnje po omrežju zmanjša. Simulacije motenj v inverznem času za zazankani model in razvejan model EES(elektroenergetski sistem) za časovno oddaljenost izvora motnje t=2s pravilno locirajo izvor motnje za 10% negotovost poznavanja reaktanc vodov in 5% negotovost poznavanja vztrajnostnih konstant generatorjev. Z ustvarjenim orodjem lahko simuliramo motnjo na poljubni topologiji omrežja in analiziramo vpliv parametrov omrežja in njegove topologije na širjenje motnje. Prav tako lahko analiziramo vpliv parametrov omrežja in topologije na rekonstrukcijo motnje in lociranje mesta izvora motnje s simulacijo v inverznem času.The aim of this thesis was to investigate electromechanical wave propagation in power systems. Different electrical grid topologies have been modeled where buses are connected with other buses with lines modeled as reaktance. Each bus is also connected to generator with transient reactance and inertia constant. Generator swing equations have been linearized at operating points and a system of first order linear differencial equations has been created. Using these equations we can calculate the values of state variable and their derivatives for the next or previous moment. Electromechanical wave propagation and reflection on the physical enges of the grid were in line with expectations. Using inverse time simulation fault reconstruction can be observed. Fault locator identifies the correct generator as a source of disturbance. Increasing either line reactance or inertia constant of the generators resaults in decrease of electromechanical wave propagation speed. Inverse time simulation for intermeshed and branched power systems has been conducted. For fault time distance of t=2s, reactance uncertainty of 10% and generator inertia constant uncertainty of 5% fault location source can be identified. Using the created simulator various different grid topologies can be simulated and impact of different grid parameters on electromechanical wave propagation can be identified. The impact of grid topology and parameters on inverse time reconstruction and fault location accuracy can also be analysed

Parallel random number generation

We present a library of 19 pseudo-random number generators, implemented for graphical processing units. The library is implemented in the OpenCL framework and empirically evaluated using the TestU01 library. Most of the presented generators pass the tests. The generators' performance is evaluated on five different devices. The Tyche-i generator is the best choice overall, while on some specific devices other generators are better

Autoencoder based generators of semi-artificial data

The goal of the thesis is to alleviate the problem of insufficient data available for data analysis or machine learning. We developed a generator of semi-artificial data based on autoencoders. We implemented dynamic autoencoders without any predefined structure, as we wanted that our solution is general and may therefore be used on any data set. Results showed that autoencoder based generators work better than variational autoencoders. The generators perform best on data sets with a small number of mixed attributes and balanced classes. They perform better if more training instances are available. Results additionally show that grid search significantly improves the performance and that it is possible to predict a good set of parameters for each data set

Performance analysis of random number generator based on breakdown diode noise

Generatorji naključnih števil igrajo pomembno vlogo pri zagotavljanju varnosti podatkov. Omogočajo večjo varnost podatkov uporabnikov na spletu, uporabljajo se v mnogih industrijskih aplikacijah, medicini, vojski, policiji, igrah na srečo in drugje. V diplomskem delu opišemo osnovne tipe generatorjev naključnih števil. Možen izvor naključnosti predstavlja šum elektronskih elementov, v delu se osredotočimo na generator naključnih števil na osnovi šuma prebojnih diod. Za analizo stopnje naključnosti naredimo poenostavljeni model vezja in izpeljemo analitično enačbo za določitev entropije generatorja. Na koncu opišemo kako lahko zagotovimo višjo entropijo, ne da bi pri tem spremenili vezje.Random numbers generators play an important role in data security. They are used for bigger security of users online, in many industrial applications, in medical, military and police facilities, they are being used in gambling and elsewhere. In this thesis we describe basic types of random numbers generators and possible source of randomness as noise of electrical components. In this thesis we focus on random numbers generators with principle of avalanche diode. For analysis of randomness we make a simplified circuit model and derive an analytical formula for entropy of simplified circuit. In the end, we describe how we can ensure a higher entropy, without changing the circuit