Discrete wavelet transforms and applications

U ovom diplomskom radu je opisana diskretna wavelet transformacija (DWT), te mogućnost primjene u obradi slike. TakoĎer u radu je prvo obraĎivana teorijska podloga za uspješno opisivanje teme diplomskog rada, a kasnije se iz teorijskog znanja išlo na praktičnu primjenu istih. Poslije definiranja pojmova kontinuirana wavelet transformacija (CWT), diskretna wavelet transformacija (DWT), išlo se na definiranje algoritama za Huffmanovo i Aritmetičko kodiranje u wavelet kompresiji slike. TakoĎer je objašnjena procedura dobivanja rekonstruirane iz ulazne slike, primjenom DWT-a, IDWT-a, kvantizacije, inverzne kvantizacije i entropijskog kodiranja/dekodiranja. U praktičnom dijelu su usporeĎivana tri algoritma po omjeru kompresije i brzini kodiranja/dekodiranja. Iz rezultata je proizišlo da Huffmanov algoritam za kodiranje/dekodiranje posjeduje najveću učinkovitost, koja je rasla povećanjem razine dekompozicije (barem do treće razine). Najveći omjer kompresije postiţe algoritam aritmetičko koje čini rekurzivno kodiranje/dekodiranje. Porastom razine dekompozicije raste SNR i SSIM mjera za odreĎivanje kvalitete. U drugom dijelu su usporeĎivane slike s različitim postotkom sačuvanih wavelet koeficijenata. Za 1% posto sačuvanih wavelet koeficijenata na slici, teško je bilo uočljivo što slika zapravo predstavlja. Porastom postotka sačuvanih wavelet koeficijenata na slici, slika je posjedovala značajno više detalja. Iz objektivnih mjera za odreĎivanje kvalitete slika „lena“ je bila sličnija originalu gledano po vrijednostima za SNR i SSIM. Slika „lena“ je posjedovala veći omjer kompresije u odnosu na sliku „priroda“, te na taj način je saţeta slika „lena“ zauzimala manje memorijskog prostora.Discrete wavelet transformation (DWT) was described in this master thesis, and the possibility of applying it to the processing of digital pictures. In this thesis firstly was covered theoretical background for successfull coverage of the subject, and then it's application on pictures. After defining concepts such as Continuous wavelet transformation (CWT) and Discrete wavelet transformation (DWT), there is defining algorithms for Huffman and Arithmetic Coding in wavelet compression of pictures. It is also explained the procedure of obtaining reconstructed from the input image, using DWT, IDWT, quantization, inverse quantization and entropy coding/decoding. In practical part of thesis, three algorithms were compared by compression ratio and coding/decoding speed. From results, it is shown that Huffman algorithm for coding/decoding possesses best effectiveness which increased by enhancement of decomposion level (at least by third level). Best compression ratio achieves Arithmetic algorithm which is made of recursive coding/decoding. Increasement of level of decomposition results in increasement of SNR and SSIM criterions for assessment of quality. In second part of thesis, there are compared pictures with different percentage of preserved wavelet coefficients. For 1% of preserved wavelet coefficients of pictures, it was hard to spot what picture actually represents. By increasing percentage of wavelet coefficients, picture showed increased number of details. From objective criterion used in defining quality of picture, picture „lena“ was closest in quality to original picture using SNR and SSIM values. Picture „lena“ possesed higher compression ratio in regards to picture „priroda“, and because of that it used less memory

Fiber Optic Transmission Systems

Svjetlovodni prijenosni sustav su de facto standard današnjice svakog komunikacijskog sustava. Postupak prijenosa podataka u svjetlovodnim prijenosnim sustavima kreće od izvora signala što predstavlja led dioda ili laser. Za prijenos podataka u svjetlovodnim sustavima koristi se svjetlovodna nit, a na kraju sustava nalazi se fotodioda koja se koristi za primanje podataka, odnosno detekciju signala. Cilj ovog rada je analizirati komponente, građu, korištenje, dijelove svjetlovodnih prijenosnih sustava teanalizirati postupke valnog multipleksiranja kao i mogućnosti primjene.Fiber optics transmission system is nowadays de-facto standard of every communication system. Data transmission in fiber optics systems starts from the source such as LED or laser. For actual transmission fiber thread is used which ends with a photodiode which is used for signal detection. Therefore, the goal of this paper is to describe components, materials, and use of fiber optic transmission systems, as well as to analyze multiplexing techniques and application possibilities

Application of PSVR-DNS Algorithm for Attacker Detection and Isolation

The DNS (Domain Name System) is used to map and convert human-friendly domain names to the numeric IP (Internet Protocol) addresses. As with the operation of any communication system, there are some security risks associated with the operation of DNS. Actions targeting the availability or stability of a network\u27s DNS service are considered DNS attack. For example, a high volume of traffic and a large number of requests coming to DNS servers are part of a type of DoS (Denial of Service) attack that uses DNS for amplification. Although most DNS servers are open source, some commercial protective DNS services are available for network traffic control, filtering and automatic blocking of requests to undesirable, dangerous or malicious internet domains, but the price of such services is high. In this paper, a new PSVR-DNS (Probability Support Vector Regression-Domain Name System) algorithm is proposed for the purpose of detecting and isolating attackers who pose a threat to an uninterrupted work of the DNS servers. The main focus is on the prevention of the DNS cache poisoning. The collected results showed that the proposed PSVR-DNS algorithm achieves better performance related to faster detection and isolation of attacks compared to some existing algorithms

Fast Fourier transform and application in image processing

U ovom radu je primjenjena brza Fourierova transformacija u obradi slike pomoću programa matlab. Vremenska diskretna Fourierova transformacija predstavlja Fourierovu transformaciju za vremenske diskretne signale. U obradi digitalne slike vremenska diskretna Fourierova transformacija se proširila na 2D vremensku diskretnu Fourierovu transformaciju, zato što je digitalna slika dvodimenzionalna. Primjenom 2D vremenske diskretne Fourierove transformacije na matricu slike, pretvorba slike se vrši iz prostorne domene u frekvencijsku domenu. U obradi slike razlikuje se prostorno i frekvencijsko područje. Slike su filtrirane u frekvencijskoj domeni. Filtriranje u frekvencijskoj domeni zahtjeva manju računsku složenost. Prevođenjem frekvencijskog filtera u konvolucijsku masku dobije se aproksimacija najmanje kvadratne greške[35]. Ako je frekvencijski filtar realan i simetričan, tada će konvolucijska maska biti također realna i simetrična. U slučaju nemogućnosti određivanja dovoljno dobre maske za aproksimaciju filtra ili ako aproksimacijom filtra dobivamo veliku konvolucijsku masku, tada se filtriranje provodi u frekvencijskom području. Iz tog razloga filtriranje u frekvencijskoj domeni zahtjeva manju računsku složenost za razliku sa konvolucijom s velikim maskama.In this work was applied fast Fourier transformation in picture processing with program matlab. Time discrete Fourier transform presents Fourier transform of discrete-time signals. In digital image processing time discrete Fourier transform expands to two-dimensional time discrete Fourier transform, because the digital image is two-dimensional. By applying the twodimensional discrete-time Fourier transform on the matrix image, image conversion is made from the spatial domain to the frequency domain. In image processing it differs spatial and frequency domain. Pictures are filtered in frequency domain. Filtering in frequency domain require lower calculation complexity. By transfering frequency filter in convolution mask it gets approximation of least square mistake. If the frequency filter is realistic and simetric, then convolution mask will also be realistic and simetric. In cases where determination of mask for approximation filter isn't good enough or if with approximation of filter results with large convolution mask, then filtering is carried out in frequency domain. Because of that reason filtering in frequency domain requests lower calculation complexity compared to convolution with large masks

Discrete wavelet transforms and applications

U ovom diplomskom radu je opisana diskretna wavelet transformacija (DWT), te mogućnost primjene u obradi slike. TakoĎer u radu je prvo obraĎivana teorijska podloga za uspješno opisivanje teme diplomskog rada, a kasnije se iz teorijskog znanja išlo na praktičnu primjenu istih. Poslije definiranja pojmova kontinuirana wavelet transformacija (CWT), diskretna wavelet transformacija (DWT), išlo se na definiranje algoritama za Huffmanovo i Aritmetičko kodiranje u wavelet kompresiji slike. TakoĎer je objašnjena procedura dobivanja rekonstruirane iz ulazne slike, primjenom DWT-a, IDWT-a, kvantizacije, inverzne kvantizacije i entropijskog kodiranja/dekodiranja. U praktičnom dijelu su usporeĎivana tri algoritma po omjeru kompresije i brzini kodiranja/dekodiranja. Iz rezultata je proizišlo da Huffmanov algoritam za kodiranje/dekodiranje posjeduje najveću učinkovitost, koja je rasla povećanjem razine dekompozicije (barem do treće razine). Najveći omjer kompresije postiţe algoritam aritmetičko koje čini rekurzivno kodiranje/dekodiranje. Porastom razine dekompozicije raste SNR i SSIM mjera za odreĎivanje kvalitete. U drugom dijelu su usporeĎivane slike s različitim postotkom sačuvanih wavelet koeficijenata. Za 1% posto sačuvanih wavelet koeficijenata na slici, teško je bilo uočljivo što slika zapravo predstavlja. Porastom postotka sačuvanih wavelet koeficijenata na slici, slika je posjedovala značajno više detalja. Iz objektivnih mjera za odreĎivanje kvalitete slika „lena“ je bila sličnija originalu gledano po vrijednostima za SNR i SSIM. Slika „lena“ je posjedovala veći omjer kompresije u odnosu na sliku „priroda“, te na taj način je saţeta slika „lena“ zauzimala manje memorijskog prostora.Discrete wavelet transformation (DWT) was described in this master thesis, and the possibility of applying it to the processing of digital pictures. In this thesis firstly was covered theoretical background for successfull coverage of the subject, and then it's application on pictures. After defining concepts such as Continuous wavelet transformation (CWT) and Discrete wavelet transformation (DWT), there is defining algorithms for Huffman and Arithmetic Coding in wavelet compression of pictures. It is also explained the procedure of obtaining reconstructed from the input image, using DWT, IDWT, quantization, inverse quantization and entropy coding/decoding. In practical part of thesis, three algorithms were compared by compression ratio and coding/decoding speed. From results, it is shown that Huffman algorithm for coding/decoding possesses best effectiveness which increased by enhancement of decomposion level (at least by third level). Best compression ratio achieves Arithmetic algorithm which is made of recursive coding/decoding. Increasement of level of decomposition results in increasement of SNR and SSIM criterions for assessment of quality. In second part of thesis, there are compared pictures with different percentage of preserved wavelet coefficients. For 1% of preserved wavelet coefficients of pictures, it was hard to spot what picture actually represents. By increasing percentage of wavelet coefficients, picture showed increased number of details. From objective criterion used in defining quality of picture, picture „lena“ was closest in quality to original picture using SNR and SSIM values. Picture „lena“ possesed higher compression ratio in regards to picture „priroda“, and because of that it used less memory

Analysis of Optical Access Network Implementation in Peščenica Municipality

Svrha istraživanja diplomskog rada je analizirati tip naselja u koji pripada općina Peščenica, korištenjem podataka o broju stanovnika i površine, te primijeniti odgovarajući model kako bi se utvrdili troškovi polaganja svjetlovodne pristupne mreže.U radu je napravljeno anketno istraživanjem koje obuhvaća stanovnike sa područja općine Peščenice, kako bi dobili informacije o tipu usluge koju korisnici koriste i samoj cijeni usluge. Pomoću cijene usluge,izračunava se dobit operatora korištenjem svjetlovodne infrastrukture na općini Peščenica.The purpose of the research thesis is to analyze the type of settlement in which it belongs to the municipality of Peščenica, using data on the number of inhabitants and areas, applying the appropriate model to determine the cost of laying the fiber access network. The paper is a survey that will include residents from the municipalities of Peščenice, in order to obtain information on the type of services used by users and only valued services. Using the price of services, we will calculate the profit of the operator using the fiber optic infrastructure in the municipality of Peščenica

Discrete wavelet transforms and applications

U ovom diplomskom radu je opisana diskretna wavelet transformacija (DWT), te mogućnost primjene u obradi slike. TakoĎer u radu je prvo obraĎivana teorijska podloga za uspješno opisivanje teme diplomskog rada, a kasnije se iz teorijskog znanja išlo na praktičnu primjenu istih. Poslije definiranja pojmova kontinuirana wavelet transformacija (CWT), diskretna wavelet transformacija (DWT), išlo se na definiranje algoritama za Huffmanovo i Aritmetičko kodiranje u wavelet kompresiji slike. TakoĎer je objašnjena procedura dobivanja rekonstruirane iz ulazne slike, primjenom DWT-a, IDWT-a, kvantizacije, inverzne kvantizacije i entropijskog kodiranja/dekodiranja. U praktičnom dijelu su usporeĎivana tri algoritma po omjeru kompresije i brzini kodiranja/dekodiranja. Iz rezultata je proizišlo da Huffmanov algoritam za kodiranje/dekodiranje posjeduje najveću učinkovitost, koja je rasla povećanjem razine dekompozicije (barem do treće razine). Najveći omjer kompresije postiţe algoritam aritmetičko koje čini rekurzivno kodiranje/dekodiranje. Porastom razine dekompozicije raste SNR i SSIM mjera za odreĎivanje kvalitete. U drugom dijelu su usporeĎivane slike s različitim postotkom sačuvanih wavelet koeficijenata. Za 1% posto sačuvanih wavelet koeficijenata na slici, teško je bilo uočljivo što slika zapravo predstavlja. Porastom postotka sačuvanih wavelet koeficijenata na slici, slika je posjedovala značajno više detalja. Iz objektivnih mjera za odreĎivanje kvalitete slika „lena“ je bila sličnija originalu gledano po vrijednostima za SNR i SSIM. Slika „lena“ je posjedovala veći omjer kompresije u odnosu na sliku „priroda“, te na taj način je saţeta slika „lena“ zauzimala manje memorijskog prostora.Discrete wavelet transformation (DWT) was described in this master thesis, and the possibility of applying it to the processing of digital pictures. In this thesis firstly was covered theoretical background for successfull coverage of the subject, and then it's application on pictures. After defining concepts such as Continuous wavelet transformation (CWT) and Discrete wavelet transformation (DWT), there is defining algorithms for Huffman and Arithmetic Coding in wavelet compression of pictures. It is also explained the procedure of obtaining reconstructed from the input image, using DWT, IDWT, quantization, inverse quantization and entropy coding/decoding. In practical part of thesis, three algorithms were compared by compression ratio and coding/decoding speed. From results, it is shown that Huffman algorithm for coding/decoding possesses best effectiveness which increased by enhancement of decomposion level (at least by third level). Best compression ratio achieves Arithmetic algorithm which is made of recursive coding/decoding. Increasement of level of decomposition results in increasement of SNR and SSIM criterions for assessment of quality. In second part of thesis, there are compared pictures with different percentage of preserved wavelet coefficients. For 1% of preserved wavelet coefficients of pictures, it was hard to spot what picture actually represents. By increasing percentage of wavelet coefficients, picture showed increased number of details. From objective criterion used in defining quality of picture, picture „lena“ was closest in quality to original picture using SNR and SSIM values. Picture „lena“ possesed higher compression ratio in regards to picture „priroda“, and because of that it used less memory

Analysis of Optical Access Network Implementation in Peščenica Municipality

Svrha istraživanja diplomskog rada je analizirati tip naselja u koji pripada općina Peščenica, korištenjem podataka o broju stanovnika i površine, te primijeniti odgovarajući model kako bi se utvrdili troškovi polaganja svjetlovodne pristupne mreže.U radu je napravljeno anketno istraživanjem koje obuhvaća stanovnike sa područja općine Peščenice, kako bi dobili informacije o tipu usluge koju korisnici koriste i samoj cijeni usluge. Pomoću cijene usluge,izračunava se dobit operatora korištenjem svjetlovodne infrastrukture na općini Peščenica.The purpose of the research thesis is to analyze the type of settlement in which it belongs to the municipality of Peščenica, using data on the number of inhabitants and areas, applying the appropriate model to determine the cost of laying the fiber access network. The paper is a survey that will include residents from the municipalities of Peščenice, in order to obtain information on the type of services used by users and only valued services. Using the price of services, we will calculate the profit of the operator using the fiber optic infrastructure in the municipality of Peščenica

Analysis of Optical Access Network Implementation in Peščenica Municipality

Svrha istraživanja diplomskog rada je analizirati tip naselja u koji pripada općina Peščenica, korištenjem podataka o broju stanovnika i površine, te primijeniti odgovarajući model kako bi se utvrdili troškovi polaganja svjetlovodne pristupne mreže.U radu je napravljeno anketno istraživanjem koje obuhvaća stanovnike sa područja općine Peščenice, kako bi dobili informacije o tipu usluge koju korisnici koriste i samoj cijeni usluge. Pomoću cijene usluge,izračunava se dobit operatora korištenjem svjetlovodne infrastrukture na općini Peščenica.The purpose of the research thesis is to analyze the type of settlement in which it belongs to the municipality of Peščenica, using data on the number of inhabitants and areas, applying the appropriate model to determine the cost of laying the fiber access network. The paper is a survey that will include residents from the municipalities of Peščenice, in order to obtain information on the type of services used by users and only valued services. Using the price of services, we will calculate the profit of the operator using the fiber optic infrastructure in the municipality of Peščenica