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Effect of temperature on the performance of photovoltaic cells
No full textSunčeva energija predstavlja jedan od najvažnijih obnovljivih izvora energije, ključan
za smanjenje ovisnosti o fosilnim gorivima, a time i ublažavanje klimatskih promjena. U teorijskom dijelu
ovog završnog rada objašnjeni su pojam i vrste Sunčevog zračenja kao i njegova geometrija, nakon čega
se nastavlja s pojašnjenjem pojmova fotonaponska ćelija, modul te objašnjenjem njihovog principa
djelovanja. U praktičnom dijelu rada provedena su mjerenja na dva različita fotonaponska modula,
Panasonic VBH240SE10 i Solar Frontier SF150-S, koristeći uređaj METREL MI 3108 Eurotest PV. Mjerio se
napon praznog hoda i temperatura modula u svrhu istraživanja kakav utjecaj promjene u temperaturi
imaju na njihove performanse. Rezultati mjerenja pokazali su da porast temperature dovodi do
smanjenja napona praznog hoda, što posljedično smanjuje učinkovitost modula.Solar energy is one of the most important renewable energy sources, crucial for reducing
dependence on fossil fuels and, consequently, mitigating climate change. In the theoretical part of this
undergraduate thesis, the concept and types of solar radiation, as well as its geometry, are explained,
followed by an explanation of photovoltaic cells and modules, including their operating principles. In the
practical part of this undergraduate thesis, measurements were conducted on two different
photovoltaic modules, the Panasonic VBH240SE10 and Solar Frontier SF150-S, using the METREL MI
3108 Eurotest PV device. The open-circuit voltage and module temperature were measured to
investigate how temperature changes affect their performance. The measurement results showed that
an increase in temperature leads to a decrease in open-circuit voltage, which consequently reduces the
efficiency of the modules
Malicious attack detection using machine learning
No full textCilj ovog rada bio je odrediti i primijeniti tok učenja odabranih algoritama klasifikacije
iz skupova podataka koji opisuju različite vrste malicioznih napada i definirati procedure unutar tog toka.
Opisani su maliciozni napadi koji predstavljaju prijetnju kao što su trojanski konj, mrežna krađa
identiteta, virus i distribuirani napadi uskraćivanjem usluga te se pruža uvid u tradicionalne načine
obrane od ovih napada. Osim toga, objašnjen je pojam strojnog učenja i zadatak klasifikacije kao
posebne vrste nadziranog strojnog učenja. Pregledom literature, prikazani su problemi u kojima je
korišteno strojno učenje za izgradnju sustava za obranu od malicioznih napada. Analizirani su
klasifikacijski algoritmi korišteni u radu te su predstavljene tehnike za odabir značajki i rad sa
nebalansiranim skupovima podataka. U posljednjem dijelu rada predstavljene su informacije o
korištenim skupovima podataka i objašnjene su postavke i metodologije u procesu učenja. Procijenjena
je efikasnost metoda za odabir značajki i tehnika uzorkovanja te je analiziran njihov doprinos poboljšanju
modela. Prilikom klasifikacije malicioznih napada najbolje rezultate ostvario je algoritam stablo odluke .
Nasuprot njemu, najlošije se pokazao algoritam Naive Bayes. Upotrebom tehnika za odabir značajki
modeli ostvaruju jednako dobre ili bolje performanse smanjenjem broja značajki. SFS omotač je jedna od
tehnika koja se ističe zbog doprinosa u poboljšanju modela. Smanjenjem stupnja neuravnoteženosti
skupova podataka performanse rastu upotrebom tehnike nasumičnog preuzorkovanja.The goal of this work was to determine and apply the learning flow of selected classification
algorithms from data sets describing different types of malicious attacks and to define the procedures
within that flow. Malicious attacks such as Trojan horses, phishing, viruses, and distributed denial-ofservice
attacks are described, and traditional defenses against these attacks are provided. In addition,
the concept of machine learning and the task of classification as a special type of supervised machine
learning are explained. By reviewing the literature, problems in which machine learning was used to
build a system to defend against malicious attacks were presented. The classification algorithms used in
the work were analyzed and the techniques for features selection and handeling imbalanced data sets
were presented. In the last part, information on the used data sets is presented and the settings and
methodologies in the learning process are explained. The effectiveness of feature selection methods and
sampling techniques was evaluated and their contribution to model improvement was analyzed. When
classifying malicious attacks, the decision tree algorithm achieved the best results. In contrast, the Naive
Bayes algorithm performed the worst. By using feature selection techniques, models achieve equal or
better performance by reducing the number of features. The SFS wrapper is one of the techniques that
stands out for its contribution to model improvement. By reducing the imbalance ratio of data sets,
performance increases using the random oversampling technique
Student accommodation in private housing units by means of a web application
No full textU ovom radu razvijena je web aplikacija koja omogućavanja pronalazak i kontinuirano
iznajmljivanje studentskog smještaja. Poslovna logika aplikacije razvijena je u obliku REST API
programskog sučelja uz pomoć Symfony razvojnog okvira, dok je korisničko sučelje implementirano uz
pomoć NextJS biblioteke. Aplikacija omogućava najmodavcima kreiranje i upravljanje oglasima za
nekretnine, dok studentima omogućava detaljnu pretragu ali i stupanje u kontakt sa najmodavcem uz
pomoć ugrađenog komunikacijskog sustava. Osim toga aplikacija omogućava kreiranje i upravljanje
korisničkim računom.In this paper, a web application has been developed that enables the search and continuous
rental of student accommodation. The business logic of the application is developed in the form of a
REST API interface using the Symfony framework, while the user interface is implemented using the
NextJS library. The application allows landlords to create and manage property listings, while students
are enabled to perform detailed searches and contact the landlord using the built-in communication
system. Additionally, the application allows for the creation and management of user accounts
Bluetooth 5.0
No full textBluetooth tehnologija je od svog osnutka 1994. godine jedan od ključnih pokretača
bežične komunikacije između uređaja. Svojim kontinuiranim razvojem, svaka nova verzija Bluetooth-a
donosi poboljšanja u brzini prijenosa podataka, energetskoj učinkovitosti, sigurnosti i cjelokupnoj
funkcionalnosti. Ovaj rad usmjeren je na Bluetooth verziju 5.0 koja je uvela značajna poboljšanja,
uključujući povećani domet, veću brzinu prijenosa podataka i unaprijeđenu podršku za IoT (Internet of
Things) uređaje. Rad pruža detaljnu analizu tehničkih karakteristika, sigurnosnih protokola i praktičnih
primjena Bluetooth 5.0. Uspoređuje se Bluetooth tehnologija s drugim bežičnim tehnologijama,
naglašava se njegova uloga u različitim industrijama te raspravlja o potencijalnim sigurnosnim rizicima.
Na kraju, prikazana je praktična demonstracija signalizacije između Bluetooth uređaja, pokazujući
njegovu primjenu i performanse u stvarnom svijetu.
ključne riječi (hrvatski ): Bluetooth 5.0, bežična komunikacija, IoT, prijenos podataka, sigurnost,
enkripcija, mobilni uređaji, prijenos signala.Bluetooth technology has been one of the key drivers of wireless communication between
devices since its inception in 1994. With its continuous development, each new version of Bluetooth
brings improvements in data transfer speed, energy efficiency, security and overall functionality. This
paper focuses on Bluetooth version 5.0, which introduced significant advancements, including increased
range, higher data transfer speeds, and enhanced support for IoT (Internet of Things) devices. The paper
provides a detailed analysis of the technical characteristics, security protocols, and practical applications
of Bluetooth 5.0. It compares Bluetooth technology with other wireless technologies, highlights its role
in various industries, and discusses potential security risks. Finally, a practical demonstration of signaling
between Bluetooth devices is presented, showcasing its real-world application and performance
ABS system for bicycles
No full textPodjela na segmente kao što su planiranje i istraživanje sve do izrade konstrukcije
ABS-a je prikazano. Cijeli proces izrade od samog planiranja sklopovskog rješenja koje se je razvijalo kako
su se dodavale nove komponente. Sklopovsko rješenje je u suštini ostalo nepromijenjeno. Konstrukcija
je usko vezana uz njega te se nije mogla započeti dok se prvi prototip nije napravio. Taj prototip je
pokazao greške i moguća unaprjeđenja koja se mogu napraviti kako bi krajnje rješenje bolje
funkcioniralo. Ta unaprjeđenja se vide u urednosti i preciznosti tijekom lemljenja, promjenom licnastih
žica u one punog presjeka i promjena senzora kako bi se pojednostavio program. Završni korak je
testiranje koje je pokazalo predviđene rezultate. Bicikl je bolje funkcionirao s ABS-om na klizavim
površinama dok je na suhoj podlozi kao asfalt produlji put kočenja.The division into segments such as planning and research up to the creation of ABS structure is
shown. The entire production process, from the very planning of the circuit simulation, which was
developed as new components were added. The assembly solution is essentially unchanged. The
construction is closely related to it and could not be started until the first prototype was made. That
prototype showed bugs and possible improvements that could be made to make the final solution work
better. These improvements can be seen in the neatness and precision during soldering, changing the
individual wires to those of the full section, and changing the sensors to simplify the program. The final
step is the testing that shows the predicted results. The bike worked better with ABS on slippery
surfaces, while on dry surfaces like asphalt, the braking distance was longer
Simulation Model of Asynchronous Motor Powerd by Frequency Converter
No full textAsinkronim motorima najveći problem bila je mogućnost podešavanja brzine vrtnje.
Razvojem tehnologije došlo je do razvoja energetske elektronike što je omogućilo razvoj frekvencijskih
pretvarača što je efikasno rješenje sa malo gubitaka. Zahvaljujući tome, primjena asinkronih motora u
širokom spektru industrije procesa i pogona postala je moguća. U ovom završnom radu snimao sam i
analizirao karakteristike asinkronog motora napajanog frekvencijskim pretvaračem. Snimanje je
obavljeno preko simulacijskog modela u MATLAB-u gdje je moguće testiranje rada motoru pri
mijenjanjem određenih parametara motora. Na osnovu snimljenih grafova analizirao sam i usporedio
ponašanje motora pri mijenjanjem napona, frekvencije izvora napajanja te mijenjanjem brzine vrtnje
osovine motora i tereta na osovinu.With asynchronous motors, the biggest problem was the ability to adjust the rotational speed.
With the development of technology, there has been a development of power electronics, which has
enabled the development of frequency converters, which is an efficient solution with low losses. Thanks
to this, the application of induction motors in a wide range of process and drive industries has become
possible. In this final paper, I recorded and analyzed the characteristics of an asynchronous motor
powered by a frequency converter. The recording was done through a simulation model in MATLAB
where it is possible to test the operation of the engine when changing certain engine parameters. Based
on the recorded graphs, I analyzed and compared the behavior of the motor when changing the voltage,
frequency of the power source and changing the rotational speed of the motor shaft and load on the
axle
E-ink Weather Data Display
No full textU ovom završnom radu razmatran je problem prikaza meteoroloških podataka
korištenjem e-ink zaslona Inkplate 6. Razvijen je sustav za prikaz vremenskih informacija preuzetih
putem OpenWeather API-ja. Rješenje je uključivalo povezivanje uređaja na WiFi mrežu, slanje HTTP
zahtjeva za dohvaćanje podataka, njihovo raščlanjivanje te prikaz na energetski učinkovitom e-ink
zaslonu. Testiranje sustava pokazalo je da e-ink tehnologija pruža dobru čitljivost i nisku potrošnju
energije, uz određena ograničenja poput sporijeg osvježavanja i ograničenog izbora gradova. Rad je
postavio temelje za daljnju optimizaciju sustava i proširenje njegovih funkcionalnosti.
ključne riječi (hrvatski ): API, E-ink, meteorološki podaci, prikaz podataka, WiFiThis thesis addresses the problem of displaying meteorological data using the Inkplate 6 e-ink
display. A system was developed to display weather information retrieved via the OpenWeather API.
The solution involved connecting the device to a WiFi network, sending HTTP requests to fetch data,
parsing the data, and displaying it on the energy efficient e-ink display. System testing demonstrated
that e-ink technology provides good readability and low energy consumption, though it has certain
limitations such as slower refresh rates and a limited selection of cities. The project laid the groundwork
for further system optimization and expansion of its functionalities
Modelling of wave energy power plant for optimal network operation
No full textTemeljni zadatak i cilj ovoga diplomskoga rada bio je modelirati linearni generator na
morske valove od kojih će se sastojati postrojenje na morske valove. U drugome poglavlju ovoga rada
promatrani su teorijski aspekti energije valova kao i osnovni tipovi i klasifikacija postrojenja na morske
valove. Osim toga, promatrani su teorijski aspekti postrojenja na morske valove u smislu utjecaja na
elektroenergetski sustav tj. na njegovu stabilnost, kvalitetu električne energije, utjecaje na promjene
tokova snaga i ostale. Treće poglavlje ovoga rada posvećeno je modeliranju linearnog generatora s
permanentnim magnetima na morske valove. Prikazane su krivulje napona, struje i snage generatora u
različitim vremenskim intervalima i s različitim koracima uzorkovanja. U svrhu prikazivanja spomenutih
krivulja korišten je alat MATLAB dok je u svrhu modeliranja mikromreže otoka Visa i provođenja
simulacija korišten program DIgSILENT PowerFactory. Četvrto poglavlje donosi rezime cijeloga rada;
teorijskog i praktičnog (simulacijskog dijela). Posebno se osvrće na rezultate dobivenih iz simulacija.
Rezultati pokazuju da je ovakav model generatora od kojih će se sastojati postrojenje na morske valove
moguće integrirati u mikromrežu otoka Visa, s ili bez dodatnih ulaganja u pojačavanje mreže.The basic task and goal of this thesis was to model a linear generator for sea waves, which will
consist of a sea wave plant. In the second chapter of this work, the theoretical aspects of energy waves
as well as the basic types and classification of sea wave installations were observed. In addition,
theoretical aspects of sea wave plants were observed in terms of impact on the power system, i.e. on its
stability, quality of electricity, effects on changes in power flows and others. The third chapter of this
work is dedicated to the modeling of a linear generator with permanent magnets on sea waves. The
voltage, current and power curves of the generator are shown in different time intervals and with
different sampling steps. For the purpose of displaying the mentioned curves, the MATLAB tool was
used, while the DIgSILENT PowerFactory program was used for the purpose of modeling the microgrid of
the island of Visa and conducting the simulation. The fourth chapter brings the regime of the entire
work; theoretical and practical (simulation part). Special attention is paid to the results obtained from
the simulation. The results show that this type of generator model, which will consist of generators built
on sea waves, can be integrated into the microgrid of the island of Vis, with or without additional
investments in strengthening the network
Pierce-Gate oscillator design
No full textU diplomskom radu opisana je uloga takt oscilatora u digitalnim sklopovima. Prikazan
je osnovni spoj Pierce-Gate oscilatora s kristalnim rezonatorom te je pojašnjena uloga pojedinog
elementa. Dane su osnovne jednadžbe za određivanje vrijednosti elemenata Pierce-Gate oscilatora. Pri
tome obrađen je slučaj rada oscilatora s kristalom koji titra na osnovnoj frekvenciji (fundamental mode) i
s kristalom koji je predviđen za rad na njegovom trećem harmoniku (3rd overtone). Na kraju je izvedeno
mjerenje valnog oblika izlaznog signala, jittera te struje kristala.The thesis describes the role of a clock oscillator in digital circuits. The basic circuit of the
Pierce-Gate oscillator with the crystal resonator is shown and the role of each element is explained.
Basic equations for calculating the values of Pierce-Gate oscillator elements are derived. In doing so, the
case with a crystal that resonates at the fundamental frequency (fundamental mode) as well as crystal
that is designed to work at its third harmonic is observed. At the end, the output signal waveform, jitter
and crystal drive level are measured
System for object sorting in agruculture
No full textCilj ovog završnog rada bio je osmisliti, dizajnirati, izraditi i testirati pokretnu traku sa
sustavom za sortiranje objekata prema boji i zbrajanje njihove mase, te njihovo raspoređivanje u
odgovarajuće spremnike. Napravljen je osvrt na povijest pokretnih traka te analizirane prednosti i
nedostatci njihove automatizacije. Objašnjen je teorijski koncept rada trake, kao i hardversko te
softversko rješenje. Projekt se temelji na ESP32 mikrokontroleru koji je programiran uz pomoć Arduino
razvojnog okruženja. Cijeli sustav je podijeljen u tri dijela: pokretnu traku, mjerne stanice i stanice za
sortiranje predmeta.The goal of this thesis was to design, develop, and test a conveyor belt system capable of
sorting objects by color and calculating their mass, then distributing them into appropriate containers. It
includes a review of the history of conveyor belts and an analysis of the advantages and disadvantages
of their automation. The theoretical concept of the conveyor's operation, as well as the hardware and
software solutions, are explained. This thesis is based on the ESP32 microcontroller, which is
programmed using the Arduino development environment. The entire system is divided into three parts:
the conveyor belt, measuring stations, and sorting stations