1. Spektralni analizator avdio signalaAndraž Brečko, 2024, undergraduate thesis Abstract: V diplomskem delu so predstavljeni razvoj, načrtovanje in izdelava analognega spektralnega analizatorja avdio signala. V grobem vezje sestavljajo aktivni pasovnoprepustni filtri drugega reda, detektorji vršne napetosti, logični del vezja, ki skrbi za pošiljanje signalov na prava mesta, ter zadnji, četrti del, ki je sestav prikazovalnikov in so končna enota vezja. Frekvenčni razpon analizatorja sega od 20 Hz do 20 kHz. Koraki med pasovi so odvisni od njihovega števila, v našem primeru pa celoten frekvenčni spekter delimo na 16 pasov. V delu najprej po segmentih predstavimo dele vezja, ki jih najprej teoretično obrazložimo, navedemo morebitne izračune in določevanje komponent ter predstavimo sheme ter tiskanine. Sledijo meritve in ugotovitve. Kljub možnim izboljšavam vezje deluje v skladu z zastavljenimi cilji. Keywords: avdio signal, spektralna analiza, pasovnoprepustni filter, detektor vršne napetosti, preklopna vezja, stolpčni prikazovalnik Published in DKUM: 22.10.2024; Views: 0; Downloads: 31 Full text (3,57 MB) |
2. Acoustic Gender and Age Classification as an Aid to Human–Computer Interaction in a Smart Home EnvironmentDamjan Vlaj, Andrej Žgank, 2023, original scientific article Abstract: The advanced smart home environment presents an important trend for the future of human wellbeing. One of the prerequisites for applying its rich functionality is the ability to differentiate between various user categories, such as gender, age, speakers, etc. We propose a model for an efficient acoustic gender and age classification system for human–computer interaction in a smart home. The objective was to improve acoustic classification without using high-complexity feature extraction. This was realized with pitch as an additional feature, combined with additional acoustic modeling approaches. In the first step, the classification is based on Gaussian mixture models. In thesecond step, two new procedures are introduced for gender and age classification. The first is based on the count of the frames with the speaker’s pitch values, and the second is based on the sum of the frames with pitch values belonging to a certain speaker. Since both procedures are based on pitch values, we have proposed a new, effective algorithm for pitch value calculation. In order to improve gender and age classification, we also incorporated speech segmentation with the proposed voice activity detection algorithm. We also propose a procedure that enables the quick adaptation of the classification algorithm to frequent smart home users. The proposed classification model with pitch values has improved the results in comparison with the baseline system. Keywords: acoustic classification, acoustic signal processing, Gaussian mixture model, pitch analysis, smart home Published in DKUM: 11.12.2023; Views: 471; Downloads: 21 Full text (2,07 MB) This document has many files! More... |
3. Optimal control of gain and offset in direct conversion receivers : magistrsko deloAmadej Maurič, 2023, master's thesis Abstract: In the master’s thesis, the development and implementation of optimal control for direct conversion receiver is presented. A background overview of direct conversion receivers, in-phase and quadrature mixers, sampling theory, control theories, adaptive systems, and optimal control is given. The development of a system model which is later used in simulations is also presented.
Optimal control is achieved through standard control techniques, such as feedback and feedforward control, with error functions giving restrictions. Information to feed the optimal control is acquired by the system through the analog converters to the digital converters, digital to analog converters, and received signal strength indicators.
For the development and testing of optimal control, MATLAB environment was used. Simulations and presentation of the results were also done in MATLAB. Limitations, exact operation, and comments were given throughout the thesis Keywords: optimal control, direct conversion receiver, radio frequency signal, simulation, MATLAB Published in DKUM: 23.11.2023; Views: 394; Downloads: 0 |
4. Processing of signals produced by strain gauges in testing measurements of the bridgesBoštjan Kovačič, Rok Kamnik, Andrej Štrukelj, Nikolai Ivanovich Vatin, 2015, published scientific conference contribution Abstract: Practical example of signal processing from strain gauge, inductive transducer and total station measurements are used to illustrate the features of the bridge load testing measurements. FFT provides accurate representation of physical behavior for static and dynamic signals obtained when loading the bridge. As a reference measurement the signal from inductive transducer was taken. A static part of the load test was also geodetically measured and theoretically calculated. The results are comparable. Keywords: bridges, measurements, strain gauge, load test, deformation, strain, signal processing Published in DKUM: 12.07.2023; Views: 445; Downloads: 32 Full text (500,43 KB) This document has many files! More... |
5. Primerjava monitoringa in diagnostičnega načina zapisa elektrokardiograma pri diagnostiki akutnega koronarnega sindromaPeter Černe, 2021, master's thesis Abstract: Uvod: Pri diagnostiki akutnega koronarnega sindroma je elektrokardiografija ena ključnih diagnostičnih metod. EKG monitorji nam omogočajo tako monitoring, kot diagnostični način EKG zapisa, v klinični praksi pa ugotavljamo, da se zapisa medsebojno pogosto razlikujeta. Spremembe EKG zapisa so lahko posledica neustreznega sprejema signala, njegove obdelave ali zapisa EKG posnetka. Namen raziskave je ugotoviti, kako uporaba posameznega načina dela vpliva na detekcijo sprememb pri akutnem koronarnem sindromu.
Metode: V kvantitativni raziskavi smo s pomočjo simulatorja Symbio CS 1201 simulirali osem različnih srčnih ritmov, z EKG monitorjema LifePak 12 in LifePak 15 pa primerjali monitoring EKG zapise z diagnostičnim zapisom 12-kanalnega EKG posnetka. Primerjali smo tudi razliko med odkloni posameznega EKG monitorja.
Rezultati: Ugotavljamo, da so meritve obeh uporabljenih EKG-monitorjev medsebojno identične. Diagnostični EKG-zapisi so potrdili pričakovana odstopanja spojnice ST glede na posamezni simulirani srčni ritem. V monitoring načinu dela pa so prisotna večja odstopanja.
Razprava in sklep: Ustrezna diagnostika akutnega koronarnega sindroma je mogoča le ob uporabi diagnostičnega 12-kanalnega EKG zapisa, z uporabo nizkofrekvenčnega filtra 0,05 Hz. Z večjim filtriranjem v monitoring načinu dela izgubimo zanesljivost diagnostičnih sprememb spojnice ST. Keywords: elektrokardiogram, akutni koronarni sindrom, spojnica ST, EKG signal Published in DKUM: 01.12.2021; Views: 1259; Downloads: 136 Full text (3,84 MB) |
6. Signal processor for optical fiber sensors based on MEMS Fabry-Perot interferometer : master's thesisNikola Uremović, 2020, master's thesis Abstract: In the master thesis, we have created an interrogation system for measuring the change of the optical path in the Fabry-Perot interferometer caused by the strain of the surface at which it was attached to. The change of strain can be calculated via a change in optical path length which is visible as a shift in phase angle. The system will be used as a system for measuring strain, although it can be used for measuring various physical parameters that can cause a change in optical path length, such as pressure, force, temperature, etc. Initially, the theoretical background of the system and project components are represented and explained, following the building process of the electronic and optical part of the project. Lastly, the working principle and programming algorithms of a system are presented and explained. Measurement results are shown at the end, as well as the conclusion that is drawn from the thesis. Keywords: optical fibers, sensors, interferometer, signal processing Published in DKUM: 04.11.2020; Views: 1244; Downloads: 115 Full text (5,11 MB) |
7. Application of fuzzy AHP approach to selection of organizational structure with consideration to contextual dimensionsAlireza Aslani, Feryal Aslani, 2012, original scientific article Abstract: The literature of organizational structure design is relatively rich along with conceptual and complex patterns. This complexity arising from the number of elements and numerous relations in addition to the nature of variables. Thereby, the lack of operational decision-making models is felt to propose adequate structural designs in practice. In this article, the researchers employ a fuzzy multi attribute decision making model (FMADM) to select the most suitable organizational structure based on expert’s judgments and by deploying contextual dimensions of the organization. Since the organizational changes especially in the structural levels are along with resistances among involved staffs, the implementation of this model is a supportive tool in addition to help the managers to make a qualified decision and change. Keywords: organizational structure designing, business process reengineering, development management, integration, fuzzy ahpimage analysis, probabilistic modeling, signal processing, license plate recognition Published in DKUM: 28.11.2017; Views: 1461; Downloads: 374 Full text (576,00 KB) This document has many files! More... |
8. An overview of image analysis algorithms for license plate recognitionKhalid Aboura, Rami Al-Hmouz, 2017, original scientific article Abstract: Background and purpose: We explore the problem of License Plate Recognition (LPR) to highlight a number of algorithms that can be used in image analysis problems. In management support systems using image object recognition, the intelligence resides in the statistical algorithms that can be used in various LPR steps. We describe a number of solutions, from the initial thresholding step to localization and recognition of image elements. The objective of this paper is to present a number of probabilistic approaches in LPR steps, then combine these approaches together in one system. Most LPR approaches used deterministic models that are sensitive to many uncontrolled issues like illumination, distance of vehicles from camera, processing noise etc. The essence of our approaches resides in the statistical algorithms that can accurately localize and recognize license plate.
Design/Methodology/Approach: We introduce simple and inexpensive methods to solve relatively important problems, using probabilistic approaches. In these approaches, we describe a number of statistical solutions, from the initial thresholding step to localization and recognition of image elements. In the localization step, we use frequency plate signals from the images which we analyze through the Discrete Fourier Transform. Also, a probabilistic model is adopted in the recognition of plate characters. Finally, we show how to combine results from bilingual license plates like Saudi Arabia plates.
Results: The algorithms provide the effectiveness for an ever-prevalent form of vehicles, building and properties management. The result shows the advantage of using the probabilistic approached in all LPR steps. The averaged classification rates when using local dataset reached 79.13%.
Conclusion: An improvement of recognition rate can be achieved when there are two source of information especially of license plates that have two independent texts. Keywords: image analysis, probabilistic modeling, signal processing, license plate recognition Published in DKUM: 28.11.2017; Views: 1501; Downloads: 359 Full text (1,01 MB) This document has many files! More... |
9. The different methods of displacement monitoring at loading tests of bridges or different structuresBoštjan Kovačič, Rok Kamnik, Andrii Bieliatynskyi, 2016, published scientific conference contribution Abstract: By measuring the displacements and deformations at different structures we deal in the Faculty of Civil Engineering, transportation Engineering and Architecture in University of Maribor for about 20 years. At that time we measured over 600 structures. Most loading tests of bridges and Viaducts were made. The measurements of movements needed to be as precise and accurate as possible. To do that laboratory test of instruments were made to see which instrument gives us reliable results. Displacements can be determined by geodetic and physical methods, depends of the construction. The use of geodetic methods are still preferable. In the paper the measurements with the total station, the level and rotation level, photogrammetry and solutions on the field by physical methods with inductive transducers are presented. We need to measure displacements as quick as possible but efficiently because we can not repeat the measurements under the same conditions. Also the surveying on the bridge and in the lab with the comparison of methods is presented under the different hard terrain conditions - water beneath the construction, big height of the structure, unapproachability, large span structures. Keywords: bridges, measurements, strain gauge, load test, deformation, strain, signal processing Published in DKUM: 02.08.2017; Views: 1262; Downloads: 337 Full text (3,15 MB) This document has many files! More... |
10. Integracija laparoskopskih klešč na robotski sistem UR5Rok Pahič, 2016, undergraduate thesis Abstract: V diplomskem delu je predstavljena integracija laparoskopskega orodja z že vgrajenimi aktuatorji, na robota UR5. Za vmesnik med obema elementoma je uporabljena mikrokrmilniška razvojna plošča EK-TM4C1294XL, katere naloga je vodenje orodja glede na zahteve prejete z robota. Mikrokrmilnik vodi štiri servomotorje preko pulzno širinsko moduliranega signala, sprejema pa podatke iz robota preko ethernet povezave. Z robota mikrokrmilnik sprejema zahtevane vrednosti položaja posamezne osi in mu nazaj sporoča trenutni položaj osi. Robot lahko osi vodi neposredno s poslanim zahtevanim položajem ali pa pošlje ukaz v katero stran naj se premika os in kdaj naj se ustavi. Sprejete podatke mikrokrmilnik preko kinematike prijemala preračuna v zasuke osi motorja. Poslane vrednosti do servomotorje omejuje s hitrostnim vodenjem. Keywords: laparoskopsko orodje, robot UR5, EK-TM4C1294XL, TCP/IP standard, PWM signal, internetni vtičnik, TI RTOS, kinematika Published in DKUM: 07.11.2016; Views: 1437; Downloads: 116 Full text (2,62 MB) |