164 research outputs found
Substructures in complex networks with temporally and spatially dependant connections
No full textU ovome radu objašnjene su osnovne formalne definicije koje su potrebne za razumijevanje problematike zadatka. Uvedena su dva temeljna atributa (vremenska i prostorna komponenta) nad kojima se temelje analize društvenih mreža u ovome radu. Glavni cilj ovog diplomskog rada bio je analizirati društvene mreže uzevši u obzir vremensku i prostornu komponentu, te promatrati strukture mreža ovisno o tim parametrima. Programi za analizu raĎeni su u programskom jeziku Java, okružje eclipse. Opis koda, kao i sama logika koja stoji iza njega opisana je u poglavljima koja se bave algoritmima. U zadnjim poglavljima ovoga rada analizirani su rezultati tih algoritama, te zaključci analiza. Rad takoĎer sadrži i kratki uvod u programski alat Gephi, koji je korišten za prikaz i vizualizaciju grafova društvenih mreža. Nakon analize mreža s implementiranim algoritmima, rješenja su prikazivana u Gephi-u. Kao dodatak radu priložen je CD koji sadrži sve implementirane kodove i algoritme koji su korišteni u ovome radu. TakoĎer uz algoritme priložena je i digitalni zapis ovoga rada.This paper explains the basic formal definitions which are required for understanding the problem at hand. Two fundamental attributes were introduced (time and space component) and they represent the basis of the social network analysis done in this paper. Primary goal of this paper was to analyze social networks with respect to time and space components, and to observe structures of networks depending on those attributes. Programs used for this analysis were made using Java programming language, environment Eclipse. A description of the code and it's structural logic is given in the chapters concerning algorithms. In the last chapters of this paper, both the results of the work done by those algorithms were analyzed, and certain conclusions were drawn. This work also contains a short introduction in to the programming tool Gephi, which was used for the representation and visualization of graphs of social networks. After the analysis of networks with implemented algorithms was done, the results were shown in Gephi, In addition to this paper, a CD which contains all the implemented algorithms and codes is included. A digital version of this paper is included also
Impact of multi wall carbon nanotubes of photocatalytic properties of TiO2
No full textSve veća uporaba lijekova, pesticida i drugih sliĉnih proizvoda utjeĉe na oneĉišćenje vode. Takvi proizvodi spadaju u mikrooneĉišćenja koja zahtijevaju posebne uvijete proĉišćavanja. Jedan od naĉina proĉišćavanja su napredni oksidacijski procesi u koje spada i fotokazaliza. Za proces fotokatalize potrebna je prisutnost fotokatalizatora, jedan od fotokatalizatora koji se koristi u fotokatalizi je TiO2. Za poboljšanje svojstava TiO2 mogu se koristiti razliĉiti elementi, spojevi i ugljikove nanocijevi.
U radu su pripremljeni fotokatlizatori TiO2 i TiO2/višestjene ugljikove nanocijevi s razliĉitim udjelima nanocijevi nanošenih sol-gel postupkom na staklenu mrežicu. Uspješno vezanje fotokatalizatora na staklenu mrežicu potvrĊeno je vizualno i SEM/EDS analizom. Ispitana su fotokatalitiĉka svojstva razgradnjom salicilne kiseline u reaktoru sa simuliranim sunĉevim zraĉenjem. UtvrĊeno je da udio od 5 % ugljikovih nanocijevi daje najbolje rezultate razgradnje salicilne kiseline fotokatalizom.The increasing use of medicines, pesticides and other similar products is affecting water pollution. Such products belong to microimpurities that require special purification conditions. One of the methods of purification is advance oxidation processes, which include photocatalysis. Photocatalysis requires the presence of photocatalysts, one of the photocatalysts used in photocatalysis is TiO2. Various elements, compounds and carbon nanotubes can be used to improve the properties of TiO2.
In this paper photocatalysts from TiO2 and TiO2/multi walled carbon nanotubes with different proportions of nanotubes deposited by sol-gel process on a glass mesh has been prepared. The successful bonding of the photocatalyst to the glass mesh was confirmed visually and by SEM/EDS analysis. The photocatalytic properties were examined by decomposing salicylic acid in reactor with a simulated solar radiation. It was established that 5 wt.% of carbon nanotubes gave the best results for the degradation of salicylic acid by photocatalysis
Coordination in distributed systems based on low-power devices
No full textAlgoritmi elekcije koordinatora, sinkronizacije sata i međusobnog isključivanja jedni su od najbitnijih grupa algoritama koji se koriste u raspodijeljenim sustavima. Ovim su se radom opisale pretpostavke za njihovu implementaciju, izložilo se nekoliko najpoznatijih i najzanimljivijih algoritama, pojasnio se njihov rad te se osvrnulo na njihove složenosti. Opisane se algoritme implementiralo u raspodijeljeni sustav temeljen na uređajima male potrošnje. Korišteni uređaji su mikrokontroleri ESP8266-12E. Sustav je osmišljen tako da se izabere koordinator koji upravlja ostalim komponentama, a one upravljaju semaforima, pomoću međusobnog isključivanja ili HTTP poslužitelja. Veliku ulogu u radu sustava imaju opisani algoritmi.Leader election, clock synchronization and mutual exclusion algorithms are one of the most significant groups of algorithms used in distributed systems. In this thesis, assumptions for implementation of these algorithms are described, few of the most known and most interesting algorithms are presented, the way they work is explained, as well as their time complexities. Described algorithms were implemented in distributed system based on low-power microcontrollers, specifically ESP8266-12E. Leader controls other components, that control traffic lights, through usage of mutual exclusion or HTTP protocol. Described algorithms have immense influence in use of system
Management of a computer grid based on low-cost embedded computers
No full textGrozd (engl. cluster) računala je sustav povezanih računala koja surađuju u izvršavanju određenih zadataka tako da funkcioniraju kao jedno veliko računalo. Prve takve sustave izgradili su korisnici kojima je za izvršavanje radnih zadataka bilo potrebno više od jednog računala. U implementaciji grozda RaspberryPi predstavlja glavno (master) računalo, a Cubieboard2 predstavlja čvor grozda (node). Na svakom od čvorova se pri paljenju pokreće TCP poslužitelj kako bi računala međusobno komunicirala slanjem poruka putem TCP utičnica. Određenim akcijama na glavnom računalu pokrećemo TCP klijentsku aplikaciju koja razmjenjuje poruke sa određenim čvorovima.Computer cluster system contains a set of connected computers that work together in executing of certain tasks so they can be viewed as a single large computer. The first such systems were built by users who needed more than one computer to execute their tasks. In the implementation of the cluster RaspberryPi represents master computer, while Cubieboard2 represents node. On each of the nodes is starting-up TCP server so computers can communicate with each other by sending messages via TCP socket. Certain actions on the host computer initiates a TCP client application that exchanges messages with specific nodes
Human-Device Interaction Scenarios Using Voice User Interface
No full textAutomatizacija kućanstva je budućnost novih modernih domova.Glavna stavka takvih domova je korištenje glasovnog korisničkog sučelja.U ovome radu napravljen je jednostavan sustav interakcije korisnika i glasovnog sučelja koristeći glasovnu uslugu Amazon Alexa,AWS i ESP32 mikrokontrolera s povezanim senzorima.
Pomoću Alexe korisnik može slati željene upite(trenutna temperature,trenutna vlažnost,slobodna/zau\-zeta prostorija u domu) koji se zatim obrađuju unutar AWS-a.Stanje senzora se čuva unutar shadow stanja.Shadow stanje se osvježava svakih nekoliko minuta od strane lokalnog ESP32 nakon očitanja stanja spojenih senzora ili ako se detektira dolazak/odlazak iz prostorije.Komunikacija između ESP32 i AWS-a se odvija pomoću MQTT protokola.Home automation is the future of the new modern homes. The main component of these homes will be voice user interface.In this paper, a simple customer interaction system with voice interface has been developed using voice services of Amazon Alexa, AWS and ESP32 microcontroller with connected sensors. Alexa user can send desired queries (current temperature, current humidity, free / occupied room at home) which are then processed within AWS. The sensor state is stored in the shadow state. The Shadow state refreshes every few minutes by the local ESP32 after it reads the status of connected sensors or it detects someone entering/leaving desired room.Communication between ESP32 and AWS uses the MQTT protocol
Smart Surface Based on Pressure-Sensitive Textile
No full textRazvoj tehnologija uvelike je utjecao i na pojavu pametnih tkanina, odnosno izradu
tkanina s ušivenim elektroničkim osjetilima, koje su dosad svoju primjenu već pronašle
u sportskoj industriji, zdravstvu i pametnim kućanstvima. U sklopu ovog rada predložen
je prototip takvog sustava koji se sastoji od ESP32 razvojne pločice, 20 osjetila
pritiska, ručno izrađenih od vodljivih tkanina i tkanina osjetljivih na pritisak te tkanine
od filca u koju su vodljivim koncem ušivena sva osjetila. Pritiskom na pojedino osjetilo,
dolazi do promjene otpora što se manifestira u odgovarajućoj promjeni boje na
grafičkom sučelju i vizualizaciji aktivnosti na površini.The technology development has influenced the emergence of smart fabrics, that is
the production of fabrics with embedded electronic sensors, which have already found
its use in the sports industry, health care and smart homes. As part of this master’s
thesis, a prototype is proposed, consisting of an ESP32 development board, 20 pressure
sensors, handmade from conductive and pressure sensitive fabrics, and of a felt fabric
in which all sensors are sewn with a conductive thread. By applying pressure to the
sensor, there is a change in resistance which is manifested in appropriate color change
on graphical interface and the visualization of activity on the surface
Federated Learning in Embedded Systems
No full textFederalnog učenje je kolaborativna, distribuirana metoda za učenje globalnog dijeljenog modela. Koristi računalne mogućnosti krajnjih uređaja (pametni telefoni, uređaji u ugradbenim sustavima, internetu stvari, računarstvu na rubu itd.) za obavljanje procesa strojnog učenja, pri čemu se za treniranje koriste lokalni podaci. Svaki krajnji uređaj (klijentski čvor) trenira lokalni model nad svojim podacima, a centralni čvor kreira globalni model na temelju lokalnih modela. Lokalni podaci svakog klijenta, koji su često privatni, nikada se ne dijele s nekom trećom stranom i na taj način je sačuvana privatnost klijenta. Kako bi se olakšalo istraživanje federalnog učenja razvijeni su programski okviri za federalno učenje, a jedan od njih je Flower. U ovom radu proučeno je područje federalnog učenja, te programski okvir Flower i njegove karakteristike i prednosti u odnosu na slične programske okvire. Implementiran je sustav za stvaranje zajedničkog modela temeljen na programskom okviru Flower, te su ispitane performanse sustava s obzirom na dostignuti kvalitetu zajedničkog globalnog modela i modela dobivenog metodom klasičnog centralnog strojnog učenja.Federated learning (FL) is collaborative, distributed method of machine learning used to create a shared global model. It uses computing capabilities of end devices (smartphones, devices in embedded systems, IoT, edge computing etc.) for machine learning on their local data. Every end device (client node) trains a local model on its local data, while central node creates global shared model based on information from local models. Local data of each client, which is often private, is never shared with other party and privacy of clients is preserved. To make exploration and development of federated learning easier, several frameworks for federated learning have been developed, one of which is Flower. In this work the field of federated learning is described and Flower framework for federated learning is explored. Using Flower framework, system for creating a shared global model is developed and its performance is evaluated based on achieved quality of shared global model and model created using classic centralized method of machine learning
Monitoring the transport conditions of temperature-sensitive goods using blockchain technology and smart contracts
No full textOvaj rad predstavlja sustav za praćenje i arbitraciju pri transportu temperaturnih
dobara koristeći pametne ugovore i Ethereumov blok-lanac. Rad predstavlja te
tehnologije i prednosti koje pružaju u transportu hladne robe, kao što su
integritet, neporecivost, transparentnost i brzo razrješenje poslovanja
između prijevoznika i klijenta. Sustav koji rad opisuje sastoji se od
dva dijela: pametnog ugovora i IoT uređaja odnosno mjernog uređaja.
Pametni ugovor ima funkciju arbitara između prijevoznika i klijenta i
interno sprema mjerenja temperature. Mjerni uređaj prati stanje robe tijekom
transporta i periodično zapisuje mjerenja na pametni ugovor.
Na kraju rada testira sustav na testnoj mreži Goerli i izračuna se cijena
izvršavanja ovog sustava.This paper presents a system for monitoring and arbitration in cold chain
transort using smart contracts and the Ethereum blockchain. The work presents
the advantages they provide in the transport of cold goods, such as
integrity, irrefutability, transparency and quick resolution of business
between the carrier and the client. The system that the paper describes consists of
two parts: a smart contract and an IoT device, i.e. a measuring device.
The smart contract has the function of an arbitrator between the carrier and the client and
stores temperature measurements internally. The measuring device monitors the condition of the goods during
transport and periodically records the measurements on the smart contract.
At the end of the work, the system is tested on the Goerli test network and the price of execution
this system is calculated
Real-time open data streams
No full textCilj rada je proučavanje problematike implementacije tokova podataka u stvarnom vremenu specifično u okviru otvorenih podataka. Rad se osvrće na identificiranje i analizu primjene dostupnih tehnologija za implementaciju sustava tokova podataka, te se konačno razvija vlastito programsko rješenje za transformaciju pasivnog izvora podataka u sustav koji aktivno šalje podatke korisnicima.The main goal of the thesis is the study of implementation of real-time data streams primarily focusing on open data sources. The thesis focuses on identifying and analyzing the possible applications of technologies available for development of data stream systems, and developing a solution for transforming a passive data source into an active source that is continually sending data to users
A system for processing and visualization of examination data
No full textIdeja za ovaj sustav je nastala iz potrebe za automatiziranjem ispravljanja rezultata ispita, kvizova i anketa. Umjesto trenutnog klasičnog ispravljanja ovaj sustav bi omogućio automatsko ispravljanje i kasnije pregledavanje tih podataka. Tema ovog rada je dio koji se odnosi na obradu i prikaz podataka nakon što je korisnik riješio ispit. Sustav je implementiran kao web aplikacija, pomoću radnog okvira Ruby on Rails. Aplikacija je vrlo orijentirana na bazu podataka, stoga je njoj posvećeno dosta pažnje, a korištena je besplatna, otvorena baza podataka PostgreSQL. Korisnik može vidjeti sve svoje ispite, ankete i kvizove na jednom mjestu te pratiti svoje rezultate. Svoje rezultate može usporediti s drugim korisnicima te vidjeti općenitu statistiku ispita. Sustav je vrlo široko primjenjiv te bi mogao biti koristan u mnogim aspektima ljudskih djelatnosti.Idea for this system has come from a need to have automated result grading of exams, quizzes and polls. Instead of classic exam grading, this system would enable automatic grading of exam results and displaying the data afterwards. Theme of this thesis is the part of a grading system which is used to process and display the data after the user solved quiz, exam or poll. System is implemented as a web application using Ruby on Rails framework. Application is database oriented, which means a lot od dedication is given to it. As a datebase I used free, open source PostgreSQL. System enables user to see his exams, quizzes and polls in one place so he can track his progress. He can later compare his results to other user's results and also see overall exam statistics. System has wide variety of applications and could be useful in many aspects
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