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Laboratory exercise in data hiding in the audio record
Kortus, Jiří ; Jeřábek, Jan (referee) ; Burda, Karel (advisor)
The diploma thesis aims on the matter of data hiding (steganography) in audio records. It describes general steganographic principles and aims further on the specifics of data hiding in audio records and also aims on the LSB steganographic technique and suitability of different types of audio records to be used with this technique. The thesis also describes a laboratory exercise focused on steganography in audio records and influence of related aspects on the final audio record which contains secret data. Further, the thesis describes a program that was created especially for the laboratory exercise, from the design, functional as well as implementation-related view. Within the exercise, students will be able to examine how the amount of data to be hidden in the audio record and different ways of data hiding will affect quality of the resulting audio record, and therefore they can become more familiar with the matter of steganography based on the LSB method used in audio records.
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Fully-differential frequency filter designing with current active elements using signal-flow graphs method
Štork, Petr ; Jeřábek, Jan (referee) ; Langhammer, Lukáš (advisor)
This master’s thesis deals with designing of fully-differential current-mode frequency filters using signal-flow graphs method. The first part is focused on a general description of frequency filters, its function and division. Active elements that create these frequency filters, such as multi-output current follower (MO-CF), balanced or multi-output transconductance amplifier (BOTA, MOTA) and digitally adjustace current amplifier (DACA) are described in the following part. Next, problems and various techniques of designing such filters are discussed on a theoretic basis. In the remaining part of the thesis there are six circuits of frequency filters described in detail; these connections are then transferred of passive elements to a proposed connections, with the assistance of a so-called reflection. Calculations of passive form are stated, as well as results of simulations, where nondifferential and differential variations of these designed frequency filters are compared. Finaly, it has been selected some variants of designs, which has been manufactured, then measured out and resulet has been compare between each other.
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Electronically adjustable active elements for the realization of oscillators and function generators
Bokůvka, Tomáš ; Jeřábek, Jan (referee) ; Polák, Josef (advisor)
This thesis is focused on the design, analysis and realization of new oscillator and generator circuits using electronically adjustable active elements. In the opening discussion the aspects of distribution, proposal, properties and oscillation conditions of generators and oscillators are theoretically described. Next, there are presented some electronically adjustable active elements which appear to be suitable for construction of the oscillators and generators. This covers in particular the Operational Transconductance Amplifier OTA, Voltage Control Amplifier VCA and Digitally Adjustable Current Amplifier DACA. Using these elements the six oscillators and two functional generators are presented. Simulation results and design methods are included. Next part is focused on practical realization and measurement. At the end of the thesis the measurement and simulation results are discussed and compared.
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DNS protocol client with a graphical interface suitable for lecturing
Sousedík, Tomáš ; Lattenberg, Ivo (referee) ; Jeřábek, Jan (advisor)
This thesis describes DNS protocol and messages it uses to obtain desired information. The protocol is described from its creation and occasions that caused the creation of the protocol. Later on are discussed multicast capabilities of name resolution this section is focused on mDNS and LLMNR. In the second part is detailed description of the structure of the messages and their useage. In the last part is described the design of the application, which was based on the specifications listed in RFCs. One chapter is devoted to a detailed description of the application and its individual parts. A large part is devoted to the testing. There are also described problems that occurred during application development and their solutions.
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Application possibilities of controllable current amplifier
Bradáč, Josef ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
This thesis deals with the application using digitally controlled current amplifiers DACA (Digitally Adjustable Current Amplifer), which was developed at the Department of Telecommunications FEEC in cooperation with ON Semiconductor in 2010. In introduction is decribed the topic of active filters and oscillators. Farther active current components, besides DACA are described current conveyor UCC (Universal Current Conveyor), current amplifier DO-CF (Dual-Output Current Follower), MO-CF (Multiple-Output Current Follower) and FD-CF (Fully Diferential Current Follower) and operational transconductant amplifier BOTA (Balanced-Output Operational Transconductance Amplifer) and MOTA (Multiple-Output Operational Transconductance Amplifier). The following is a compilation of theories circuits using signal flow graphs, which are designed using a simulated filter circuits to control the cutoff frequency or the quality factor. Then design and simulation with auxiliary oscillator circuit AGC for controlling the oscillation frequency. Simulations are conducted with ideal models and with models that include some real properties. The conclusion of this work is devoted to the printed circuit board design for a selected filter circuit realization and measurement.
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Analysis of differential and non-differential filtering structures with adjustable current amplifier
Dvořák, Jan ; Vrba, Kamil (referee) ; Jeřábek, Jan (advisor)
The master thesis deals with designs of the single-ended and the fully-differential secondorder frequency filters with adjustable parameters. This filters operate in the current mode where main element is the current amplifier DACA (Digitally Adjustable Current Amplifier). The first part describes basic behaviour of frequency filters and distribution according to filter funcion, used parts and structure. The second part of thesis describes the design of the frequency filters by the M-C signal-flow graphs and the transformating single-ended structures to the fully-differential forms. The next part deals with properties of the active elements and their simulation models. The following part describe six circuits of the frequency filters with adjustable parameters and their simulations. Four simulation models with different properties were used for simulating of the DACA in the each circuits. The last part deals with the practical design and measurement of the selected frequency filters.
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Application possibilities of LNVGA programmable amplifier
Sobotka, Josef ; Hanák, Pavel (referee) ; Jeřábek, Jan (advisor)
This thesis deals with the theoretical description of the qualitative characteristics and parameters of some modern active elements, also discusses the theory of signal flow graphs at the level applicable for the following frequency filter design methods. The thesis is also generally discussed the issue with the circuit simulator PSpice modeling theory and voltage amplifiers on the basic 6-levels. The practical part of the work is divided into two parts. The first practical part is dedicated to design four levels of simulation model of components LNVGA element. The second practical part contains detailed theoretical proposals for three circuit structures implementing the frequency filters 2nd order (based on the basic structure of the OTA-C) using signal flow graphs with configuration options of Q and fm based on the parameters of active elements in the peripheral structure and their verification with prepared LNVGA model layers.
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Authentication using mobile phones
Fusek, Zdeněk ; Jeřábek, Jan (referee) ; Hajný, Jan (advisor)
This thesis deals with authentication by mobile phone. The mobile phone with operating system Android was chosen as authentication device. The Eclipse development environment was used for the implementation of applications. The aim of the thesis was to study and practically implement access system for mobile phones, where the Bluetooth LE and NFC interface are used for data transmission between the mobile device and reader. Firstly, the thesis deals with the client application, which is installed on the authenticated device, and then is focused on the characteristics of the application which is running on the reader. Both client and reader applications describe the design of graphical user interface, process of authentication via Bluetooth LE and NFC, analyse packages and classes, and eventually perform security analysis. The thesis also presents schema of authentication protocol HM14.
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Audio/video streaming
Čeněk, Radek ; Jeřábek, Jan (referee) ; Číka, Petr (advisor)
This thesis introduces the reader in detail with the problem of audio / video streaming overtheInternet.IntroducestechnologiesMySQL,PHP,JavaScriptandffmpegfurthermore. There is little research which examines presented similar solutions. Creating video library program shows the complexity of the problem and its possible solution. The work also finding how is compression difficult for the server.
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Design of new laboratory exercises for GNS3 environment
Barniak, Martin ; Koton, Jaroslav (referee) ; Jeřábek, Jan (advisor)
Diploma thesis deals with four laboratory tasks in simulation environment GNS3. Designed tasks are primarily focused on comparison of IPv4 and IPv6 protocols. In the first task the subject is concerned about OSPFv2 and OSPFv3 routing protocols. Next themes are transit techniques like NAT-PT and tunneling like GRE and 6to4. The second task is focused on configuration of routing protocols like EIGRP and EIGRPv6. Next sections are concerned about DHCP and ICMP protocols within IPv4 and IPv6 protocol suits. The third task is primarily focused on security relations of protocol suite IPv6. It contains OSPFv3 authentication, access lists and Cisco stateful IOS firewall. Content of the fourth task is protocol MPLS. First part of this task is concerned about basic configuration of this protocol and second part is focused on MPLS within IPv6 environment. All tasks contain test questions and individual part task.
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