Repository of the University of Rijeka, Faculty of Maritime Studies
Not a member yet
3513 research outputs found
Sort by
Detection of Non-Stationary GW Signals in High Noise From Cohen’s Class of Time–Frequency Representations Using Deep Learning
No full textAnalysis of non-stationary signals in a noisy environment is a challenging research topic in many fields often requiring simultaneous signal decomposition in the time and frequency domain. This paper proposes a method for the classification of noisy non-stationary time-series signals based on Cohen’s class of their time-frequency representations (TFRs) and deep learning algorithms. We demonstrated the proposed approach on the example of detecting gravitational-wave (GW) signals in intensive real-life, non-stationary, non-white, and non-Gaussian noise. For this purpose, we prepared a dataset based on the actual data from the Laser Interferometer Gravitational-Wave Observatory (LIGO) detector and the synthetic GW signals obtained by realistic simulations. Next, 12 different TFRs from Cohen’s class were calculated from the original noisy time-series data and used to train three state-of-the-art convolutional neural network (CNN) architectures: ResNet-101, Xception, and EfficientNet. The obtained classification results are compared to those achieved by the base model trained on the original time series. Analysis of the results suggests that the proposed approach combining deep CNN architectures with Cohen’s class TFRs yields high values of performance metrics and significantly improves the classification performance compared to the base model. The TFR-CNN models achieve the values of the classification accuracy of up to 97.10%, the area under the receiver operating characteristic curve (ROC AUC) of up to 0.9885, the recall of up to 95.87%, the precision of up to 99.51%, the F1 score of up to 97.03%, and the area under the precision-recall curve (PR AUC) of up to 0.9920. This classification performance is obtained on the dataset in which the signal-to-noise ratio (SNR) values of the raw, noisy time-series signals range from −123.46 to −2.27 dB. Therefore, this study suggests that using alternative TFRs of Cohen’s class can improve the deep learning-based detection of non-stationary GW signals in an intensive noise environment. Moreover, the proposed approach can also be a viable solution for deep learning-based analysis of numerous other noisy non-stationary signals in different practical applications
Automation of fuel separator on board
No full textTema ovog završnog rada je automatizacija separatora goriva na brodu. Separator je tlačna posuda koja se koristi za odvajanje bušotine na plinovite i tekuće komponente. Instaliraju se ili u kopnenoj stanici za obradu ili na morskoj platformi. Kako bi bili zadovoljeni zahtjevi određenih procesa, separatori su najčešće dizajnirani u određenim fazama, u kojima se separator prvog stupnja koristi za primarnu separaciju faza, dok se separator drugog i trećeg stupnja primjenjuje za daljnju obradu faze pojedinačno. Ovisno o specifičnoj primjeni separatori se nazivaju i sredstva za otplinjavanje. Kako bi se nosili s udarima tekućine koji se često javljaju tijekom proizvodnje plina ili nafte, separatori trebaju imati definiranu veličinu.The topic of this final paper is the automation of fuel separators on board. A separator is a pressure vessel used to separate a well into gaseous and liquid components. They are installed either in the land processing station or on the sea platform. In order to meet the requirements of certain processes, separators are most often designed in certain phases, in which the first stage separator is used for primary phase separation, while the second and third stage separators are used for further phase processing individually. Depending on the specific application, separators are also called degassing agents. In order to deal with liquid shocks that often occur during gas or oil production, separators need to have a defined size
Human factor in collision prevention at sea
No full textPrijevoz tereta morem kao jedan od glavnih pokretača svijeta i svjetske ekonomije u današnjici odgovoran je za održavanje i omogućavanje funkcioniranja cjelokupne ekonomije svijeta. Jedan od najvećih problema koji se pojavljuju su naravno pomorske nesreće i goleme posljedice koje proizlaze iz njih u smislu gubitka života posade i putnika, tereta te golemih šteta koje mogu nastati u ekološkom smislu. Jedne od najvećih i najznačajnijih nesreća su upravo izljevi nafte nastali većinom radi ljudskog faktora. Najbitnije inovacije koje su uvedene s ciljem smanjivanja i potpune eliminacije ljudskih pogrešaka u prijevozu morem su konvencije i propisi koji se odnose na rad i organizaciju rada na moru te konstrukcijske i sigurnosne karakteristike koje su postale obavezne za sve brodove. Analizom jedne od pomorskih nesreća takvog tipa dokazat će se posljedice ne pridržavanja danih propisa te najučestalije primjere ljudskih grešaka.Cargo shipping over sea is one of the main drivers of the world and global economy of the modern world and is responsible for maintaining and allowing the global economy to function properly. One of the biggest problems that arise are, of course, maritime accidents and the enormous consequences that result from them in terms of loss of crew and passenger lives, cargo and enormous damage that can occur in ecological terms. One of the biggest and most significant accidents was the oil spills, which were mostly caused by the human factor. The most important innovations introduced with the aim of reducing and completely eliminating human errors in sea transport are conventions and regulations relating to work and organization of work at sea and construction and safety characteristics that have become mandatory for all ships. By analysing one of the maritime accidents of this type, we will prove the consequences of non-compliance with the given regulations and the most common examples of human errors
Features of modern container and Ro-Ro terminals
No full textLakšem načinu rukovanja teretom te smanjenju troškova prijevoza određenih tereta drastično je pridonijela kontejnerizacija. Svi terminali gdje kontejner predstavlja osnovnu jedinicu tereta za odvijanje operacija nazivaju se kontejnerski terminali. Osnovne djelatnosti prilikom rada i operacija na kontejnerskom terminalu sastoje se od manipulacija s kontejnerima tijekom utovara, istovara i pretovara između različitih prijevoznih sredstva kao što su željeznica, brod, kamion ili teglenice.
Glavna značajka Ro-Ro tehnologije je teret, Ro-Ro tehnologija danas se javlja kao transport različitih vrsta tereta. Pristan za prihvat Ro-Ro brodova najčešće se sastoji od jednostavne operativne obale ili obalne rampe, što ovisi o izvedbi brodske rampe, dok terminal isključivo namijenjen za ovu vrstu tereta posjeduje interni terminalski transport, otvorene i zatvorene površine, pripadne servise i prostrana parkirališta.Containerization has drastically contributed to the way of handling cargo and to the reduction of transport costs. All terminals where the container represents the basic unit of cargo for carrying out operations are called container terminals. The basic operations at the container terminal consist of manipulations with containers during loading, unloading and transshipment between different means of transport such as rail, ship, truck or barge.
The main feature of Ro-Ro technology is cargo, RO-RO technology appears as the transport of various types of cargo. The wharf for receiving ro-ro ships usually consists of a simple operational shore or coastal ramp, which depends of the design of ship ramp. The terminal has internal terminal transport, open and closed areas, ancillary services and spacious parking lots
Control and protection system of marine diesel generator
No full textU ovom završnom radu je opisano upravljanje dizelskim generatorima i postupci zaštite dizelskih generatora čija je uloga zaštita dizelskog generatora od kvarova i oštećenja. Bitnu ulogu osim automatizacije dizelskih generatora ima i sustav upravljanja električnom energijom (PMS), kao važan čimbenik dostupnosti, sigurnosti i kvalitete proizvodnje električne energije.This final paper describes the management of diesel generators and the procedures for protecting diesel generators, the role of which is to protect the diesel generator itself from breakdowns and damage. In addition to the automatization of diesel generators, the power management system (PMS) plays an important role as an important factor in the availability, safety and quality of power generation
Impact of the road traffic on humans and the environment
No full textCestovni promet promatra se s pozitivnog i negativnog aspekta. Razvoj čovječanstva
omogućio je različite izume a tako i prijevozna sredstva, danas nužna za normalno odvijanje
prometa. Ljudi su postali ovisni o prometu posebice cestovnom iako je najznačajniji u stvaranju
negativnih učinaka na okoliš i čovjekovo zdravlje. Na razini Europske unije provode se
različite mjere u svrhu očuvanja zdravlja i okoliša te su nametnuti ciljevi i perspektive za zelenu
budućnost. Sve više se potiče razvoj i primjena vozila na alternativni pogon kao i autonomnih
vozila. Razvoj tehnologije zasigurno omogućuje stvaranje uvjeta za održivi razvoj prometa.
Rad daje uvid u negativan utjecaj cestovnog prometa na okoliš i čovjeka te načine rješavanja
problema.Road traffic is viewed from a positive and negative aspect. The development of
mankind has enabled various inventions and means of transport which are necessary for the
normal flow of traffic today. People have become addicted to road traffic even though it is most
significant in creating negative effects on the environment and human health. At the level of
the European Union, various measures are being implemented in order to preserve health and
the environment. Also, goals and perspectives for a green future have been imposed. The
development and application of alternative propulsion vehicles as well as autonomous vehicles
are increasingly encouraged. The development of technology certainly enables the creation of
conditions for the sustainable development of transport. The paper provides an insight into the
negative impact of road traffic on the environment and human as well as the ways to solve
problems
Transportation of heavy loads by the sea
No full textTehnologija prijevoza teških i vangabaritnih tereta morem je rad u kojemu je objašnjeno značenje teškog tereta, njegove osnovne karakteristike kao i karakteristike transportnih sredstava koji su konstruirani za prijevoz ove vrste tereta. Također je opisan način manipulacije teškim teretima te su navedene različite tehnologije prekrcaja koje se koriste pri rukovanju istim. Uz zaključak i uvod, rad se sastoji od još 6 poglavlja sa dodatnim podpoglavljima koji pobliže opisuju značajke teških, vangabaritnih tereta i osvrću se na razvoj i planiranje njihova transporta.Technology of transport of heavy and non-standard sized cargo by sea is a paper which explains the meaning of the heavy load, its essential characteristics as well as the characteristics of cargo handling equipment designed for the transport of this type of cargo. Method of handling heavy loads and the various transhipment technologies used during handling the same are also described in this papaer. In addition to the conclusion and introduction, the work consists of another 6 chapters with additional sub-chapters that describe the characteristics of heavy, non-standard cargo and reflect on the development and planning of their transport
Automatic ship roll stabilization
No full textU ovom završnom radu pod temom ˝Automatska stabilizacija ljuljanja broda˝ najviše će se govoriti o anti-heeling sistemu i njegovom značenju o sigurnosti broda. Pojasniti će se njegov način rada, te će se reći ponešto i o drugim načinima stabilizacije broda. Prikazati će se vrste stabilizacijskih sustava i njihove podijele.In this work under the title of ``automatic ship roll stabilization'', the focus will be on the anti-heeling system and its significance for the safety of the ship. Its mode of operation will be explained, and something will be said about other ways of stabilizing the ship. Types of stabilization systems and their divisions will be presented
Control and protection of diesel generator
No full textU ovom radu detaljno su opisani postupci zaštite i upravljanja generatora. Istaknuti postupci i reakcije sustava generatora koji su potrebni kako bi se omogućio nesmetan rad generatora i zaštita generatora, osoblje i radnog prostora. Primjenom automatike za upravljanje dizel generatora i PMS sustava (sustav za upravljanje električnom energijom) dovelo je do značajne razine kvalitete i sigurnosti proizvodnje i distribucije električne energije.This paper describes the procedures for the protection and control of generators. These procedures and reactions of the generator system, which are necessary to enable the smooth operation of the generator and the protection of the generator, personnel and workspace, are highlighted. The application of automation for the control of diesel generators and PMS systems (electricity management systems) has led to a significant level of quality and safety in the production and distribution of electricity
Financial analysis of Jadroagent d.d.
No full textU ovome završnom radu izvest ćemo financijsku analizu poslovanja tvrtke Jadroagent d.d. specijalizirane za pružanje usluga pomorskog agenta i posredovanja pri obavljanju istih. Pomoću javno dostupnih financijskih izvještaja koji sadrže obavezne financijske stavke poput računi dobiti i gubitka, bilance, izvještaja o novčanom tijeku i sl. dobiti ćemo jasniji uvid u poslovanje i opće stanje tvrtke. Također kroz rad će se objasniti i definirati navedene financijske stavke te njihovu ulogu u poslovnim knjigama i izvještajima. Zanimljiv osvrt će biti i pregled utjecaja globalne pandemije COVID 19 na poslovanje navedene tvrtke.In this bachelor thesis we will be doing horizontal financial analasys of Jadroagent d.d., agency which deals with international shipping and freight agency jobs. Our goal is to define what are financial indicators and in later part of thesis observe the impact of global pandemic of Covid 19 on financial results. We will be able to do this by using publically available financial reports which contain documents such as balance sheet, income statements and cash flow statements. We will also define and explain role of financial indicators in financial statements