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Home VoIP
Bílek, Tomáš ; Ščuglík, František (referee) ; Ráb, Jaroslav (advisor)
The thesis explores practical applications of VoIP technology at home, in combination with the opensource private branch exchange Asterisk. A substantial part of this work is the documentation of the functioning of the main parts of public switched telephone networks (PSTN) and VoIP networks. Also described are the principles of voice digitization, commonly used codecs and several VoIP protocols. The last part of the thesis focuses on the design, practical realization and verification of two home VoIP installations.
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SDL model for Source Specific Multicast
Záň, Stanislav ; Skořepa, Michal (referee) ; Šimek, Milan (advisor)
This work deals with questions of IP net communication, with using metod Source-Specific Multicast. It focused on questions of registration, unregistration and administration of clients in multicast group and IGMP protocol, which is made for this communication. Work deals also about problems of signalization between source of data and clients of multicast group.In the introduction of this work questions of communications in multicast are analyse. I tis followed by the chapter focused on the specific metod of multicast – Source Specific Multicast (SSM). Next chapter is based on the protocols in SSM, which are used for distribution of data stream in source to clients direction and also in the reverse direction. The net chapter deals with signalization of communication in SSM. It specializes for reflection and summarization metods, which are used here. This chapter also shows basic matematics formules for sending signalization packets and proposes other solutions and ways for simplify communication and minimalize delay, which is for signallization very important. After that, the work deals with differences between these two metods of signalization. The aplicationis builded in practical part of work from the knowlidge of theory from previous chapters and it simulates the real communication between data source and clients situated to multicast group. This communication is explained in MSC diagrams. The aplication also simulates both used metods of signalization and real count of cients in multicast group. The results of simulation are interpreted in the last part of work.
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Home Location Register Emulator
Juránek, Michal ; Ráb, Jaroslav (referee) ; Ščuglík, František (advisor)
This thesis presents basic structure and entities of mobile network GSM. It presents principles of signalling with focus on core network via signalling systems SS7 and SIGTRAN. Chosen protocol layers and signalling message types are presented. The thesis is concluded by the design and implementation of the application emulating home location register of mobile users.
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IMS security solutions
Porubský, Tomáš ; Rášo, Ondřej (referee) ; Mácha, Tomáš (advisor)
In the first part of my master's thesis the network architecture of IMS (IP Multimedia Subsystem) is presented. The database of subscribers HSS (Home Subscriber Server) and SLF (Subscription Locator Function), as well as a SIP CSCF servers (Call Session Control Functions) process a SIP signalization and an AS application server performing services, etc. I focus on the registration of subscribers in the IMS network with a list of transmitted messages and description of each interface that is used in this network. The most important interfaces, which I described here, are Gm, Mw, Cx, Dx and Sh. Then I focused on security in IMS problems, which are divided into categories of access security and network security. After that is the implementation of IMS network in an open source Open IMS Core System considered under the Linux operating system. Here is the problem description from the actual system installation, through the configuration of all necessary elements of the network to the communication party itself. The communication analysis in the initial registration process and in subsequent communications is described. Finally I created laboratory exercises with a focus on the Open IMS Core System, where students learn about architecture and principle of networks based on IMS technology operation, with individual elements necessary for the operation of the network and their configuration. Students also test simple captured traffic analysis.
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Possibilities of connecting the Asterisk softswitch to the 4th generation PBX
Halamík, Zdeněk ; Krajsa, Ondřej (referee) ; Šilhavý, Pavel (advisor)
This master’s thesis dissertate the possibilities of the linkage between Asterisk softswitch and the 4th generation private branch exchange. This should create a new generation’s network, so-called NGN, by the convergence of existing telecommunication networks with an IP computer network. This master’s thesis is divided into several chapters. In introduction is described the evolution of the private branch exchanges as well as the principles of the voice digitizing, codecs and signaling commonly used in both TDM and VoIP networks. The main aim of this project is the configuration of Asterisk software exchange for connection with PBX Alcatel 4400 as well as public phone network PSTN. Another goal of this master’s thesis was the configuration of Alcatel PBX and diagnostics of CCS and CAS signaling on E1 interface. In conclusion there are summarized advantages of NGN networks and their utilization in the future.
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Role of β-arrestin in μ-opioid and TRPV1 receptor signalling
Nagy Marková, Vendula ; Novotný, Jiří (advisor) ; Blahoš, Jaroslav (referee) ; Roubalová, Lenka (referee)
β-Arrestin belongs to the protein family which has a huge impact not only on GPCR signaling, but its role exceeds the function of the membrane channel, its own signaling cascade, or as a scaffold protein, etc. Here we aimed to study β-arrestin roles on the MOR behaviour in the plasma membrane or -opioid receptor (MOR) signaling and effect on adenylyl cyclase (AC) function using the siRNA to decrease the expression of β-arrestin isoforms. Furthermore, we focused on investigating the role of β-arrestin on the crosstalk between MOR and TRPV1 channels, which are important parts of pain transduction. For this purpose, we used HEK293 cells that stably expressed MOR-YFP or transiently transfected with TRPV1-CFP. We observed that both β-arrestin isoforms have an effect on the lateral mobility of MOR in the plasma membrane and the silencing of one or another β-arrestin isoforms abolishes the effect of MOR agonists to affect its diffusion in the plasma membrane. Interestingly, silencing of β-arrestin1 diminish the internalization of MOR induced by the endogenous agonist endomorphin-2. On the other hand, silencing of β-arrestin2 did not abolish the endomorphin-2 induced MOR internalization. Moreover, both isoforms exhibit a distinct impact on the inhibition of AC induced by the agonists of MOR....
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Physiological functioning of preptin and its analogs
Mrázková, Lucie ; Žáková, Lenka (advisor) ; Obšilová, Veronika (referee)
Preptin is a 34 amino acid long peptide that is derived from pro-IGF2, where it is cleaved from its E-domain and produced together with the matured IGF2. In my thesis we prepared two full-length preptins (mouse and human) and 8 preptin analogues (fragments with or without olefin metathesis). The full-length preptins as well as the preptin fragments were synthesized by solid-phase peptide synthesis. Mouse or human preptin served as our reference molecule for comparison with the results of bioassays of preptin analogues. All substances were tested for different biological activities to further elucidate the effect of preptin as a possible biologically active substance. We tested the effect on insulin secretion in pancreatic β-cells, indirectly in- vestigated the effect on bone cell proliferation and tried to approach the discovery of a possible receptor for preptin. From all our results we found that although preptin or some of its analogues have a higher effect than controls, the results are not consistent and the effect is not significantly higher. We were unsuccessful in our search for a receptor, despite having done a number of saturation experiments with radiolabelled preptin in many cell types. We also ruled out at the outset by binding experiments the possibility that preptin is able to bind...
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Role of the cannabinoid system in neurodegenerative processes
Akantisová, Lucia ; Novotný, Jiří (advisor) ; Búran, Peter (referee)
The endocannabinoid system (ECD) is involved in a significant number of physiological functions in the central and peripheral nervous system. The ECD consists of cannabinoid receptors (CB1 and CB2), endogenous ligands (ANA, 2-AG) and the enzymatic apparatus required for their synthesis (NAPE and DAGL) and degradation (FAAH, MAG). In the human brain, the cannabinoid receptor CB1 is the most widespread of the group of receptors that bind to G proteins. The signaling mechanisms of these proteins contribute to the overall homeostasis of the organism. With their activity, they affect the concentrations of second messengers, the activity of ion channels, the release of neurotransmitters, and regulate immune responses. In this context, studies in the last 20 years have focused on research in the field of neurodegenerative diseases. Today, i tis known that treatment with cannabinoid compounds improves neurological deficits associated with neuronal damage and alleviates inflammatory processes in animal models of Alzheimer's disease, Parkinson's disease and multiple sclerosis. At the clinical level, treatment with cannabinoids has helped with certain accompanying symptoms occuring in neurodegenerative diseases such as neuropathic pain, insomnia and spasticity. Key words: endocannabinoid system, cannabinoids,...
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Studies of cell signaling triggered by the TRH receptor
Trubačová, Radka
Activation of thyrotropin-releasing hormone receptor (TRH-R) signaling has an irreplaceable role in a number of cellular processes. Thyroliberin (TRH) plays an important role in the regulation of secretion of other hormones and there are also mentions of its possible antiapoptotic and neuroprotective effects. On the other hand, TRH is quickly degraded and also its other properties, such as cardiac and endocrine side effects and low lipophilicity, disadvantage the therapeutic applications of this hormone compared to its various analogues. Due to their effects on the central nervous systém, TRH and its analogues represent a potential possibility for the treatment of various neurological diseasses, including neurodegenerative disorders. The molecular mechanisms responsible for the beneficial effects of TRH and its analogues have not yet been fully elucidated. So far, little is known about the involvement of TRH, or its analogues, in the regulation of energy metabolism or impact on the cellular phosphoproteome. In the first part of the thesis, we focused on the study of the effect of TRH and interacting partners of TRH-R on the lateral mobility of this receptor in the membrane of the TRY-1 cell line stably expressing TRH-R labeled with yellow fluorescent protein (YFP) at the C-terminus. The results of...
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Studies of cell signaling triggered by the TRH receptor
Trubačová, Radka ; Novotný, Jiří (advisor) ; Brejchová, Jana (referee) ; Lazar, Josef (referee)
Activation of thyrotropin-releasing hormone receptor (TRH-R) signaling has an irreplaceable role in a number of cellular processes. Thyroliberin (TRH) plays an important role in the regulation of secretion of other hormones and there are also mentions of its possible antiapoptotic and neuroprotective effects. On the other hand, TRH is quickly degraded and also its other properties, such as cardiac and endocrine side effects and low lipophilicity, disadvantage the therapeutic applications of this hormone compared to its various analogues. Due to their effects on the central nervous systém, TRH and its analogues represent a potential possibility for the treatment of various neurological diseasses, including neurodegenerative disorders. The molecular mechanisms responsible for the beneficial effects of TRH and its analogues have not yet been fully elucidated. So far, little is known about the involvement of TRH, or its analogues, in the regulation of energy metabolism or impact on the cellular phosphoproteome. In the first part of the thesis, we focused on the study of the effect of TRH and interacting partners of TRH-R on the lateral mobility of this receptor in the membrane of the TRY-1 cell line stably expressing TRH-R labeled with yellow fluorescent protein (YFP) at the C-terminus. The results of...
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