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Yayın Design and implementation of a low cost telematic control system(Işık Üniversitesi, 2002-09) Şişman, Alper; Yarman, Bekir Sıddık Binboğa; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıThe thesis explains phases from ideation to concretize of a device that aims to solve continuously increase security needs in everyday life more effective, more reliable and cheaper way; however the device has so many application fields such as home automation projects, factory automation, SCADA systems, alarm and security systems, agricultural watering systems etc. A device that controls any desired event has been occurred, then informs the user over GSM, or activates any other electronic device when the user sends an SMS message over GSM, has been designed and realized in this thesis. All of the adjustments can be configured by user via SMS and serial port. Also all of the inform messages and output setting messages can be configured by serial port. For example, device's first input can be configured to send such a message 2Alert!3 when it is activated.Yayın Decision making and Yarsoy decision support tool(Işık Üniversitesi, 2002-09) Atasoy, Ercan; Yarman, Bekir Sıddık Binboğa; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıEvery human makes decisions in the course of his interactions with the world and other human acting in the world. To make good decisions, we need knowledge about events that occur in the world and preferences we have. Decision Support Systems try to gather information, keep it in database, classify it, give a fast and easy access to his information and by analyzing it help user to make consistent decisions. In this thesis a model driven decision support tool with the name 2YARSOY3 is developed using designated decision making models. It is developed using C++ Builder 5.0 programming tools. YARSOY is very flexible, user friendly and unique with its models. It can be used for a daily life decisions such as car or job choices, employee selection, vote selection and swot analyses. People usually make decisions by taking three or five factors into account. In order to attain the existent objectives, the events, factors and alternatives that will realize the objective must be analysed cearfully. This program gives us opportunity to evaluate, compare and analyse the events and alternatives in detail based on mathematical methods.Yayın Design and performance analysis of a novel trellis coded space-time-frequency transmission scheme(Işık Üniversitesi, 2004-07) Oğuz, Onur; Panayırcı, Erdal; Aygölü, Hasan Ümit; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıThis work is concerned with a transmitter diversity technique for wireless communications over frequency selective fading channels. The proposed technique utilizes orthogonal frequency division multiplexing (OFDM) to transform a frequency selective fading channel into multiple flat fading sub channels on which space-frequency processing is applied and then additional space-time coding is applied in order to increase the diversity. In order to improve the performance of the system, a convenient trellis coding scheme is investigated and design criteria are established. Performance of proposed space-time-frequency OFDM (STF-OFDM) transmitter diversity technique has been examined by computer simulations.Yayın Ultra wideband indoor communication(Işık Üniversitesi, 2005-07) Yirmibeş, Elif; Panayırcı, Erdal; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıUltra-wideband communication with its attractive features has received great interest from the industry and the research community. It has the potential for very high data rates with low processing powers. With its extremely wide bandwidth, multiple access capability, enhanced capability to penetrate through obstacles and its robustness to fading invites major advances in wireless communications. However, many important aspects of UWB-based communication systems have not yet been thoroughly examined. The propagation of UWB signals in indoor environments is one of the important issues with significant impacts . The amount of available UWB measurement data is very limited and more information is needed to support a comprehensive channel modeling. This paper describes the time-domain characterization of ultra-wideband propagation in indoor environments and introduces the recent proposed channel models with their effectiveness for indoor communications.Yayın Doppler radars in avionics systems(Işık Üniversitesi, 2003-08) Özel, Volkan; Aksen, Ahmet; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıAt the beginning of my thesis I give a brief information about history of Doppler radars. Then I studied the types and working principles of Doppler radars. After that I researched the avionic systems and radar types which are still using in airport surveillance. Then I studied on Doppler radars that are using in airport surveillance for negating the errors which were occurred while landing and taking off . At the end I researched a new technology Infrared Doppler radars and their working principles.Yayın Performance analysis of space time transmit diversity in UMTS under presence of carrier phase offset(Işık Üniversitesi, 2003-12) Toplu, Mehmet İlker; Panayırcı, Erdal; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıThe reguirements for the next generation of mobile communication systems are primarily driven by the explosive growth of worldwide mobile communication subscribers. Additionaly, 3G systems will allow various of new services including wireless Internet acess, high -speed mobile data services and other multimedia applications. The expected growth of subscibers and the provided services indicate the need for increased system capacity of the future mobile communication systems. This thesis deals with Transmit Diversity techniques used for capacity enhancement in the downlink. The principle of Transmit Diversity is to send the same information with two antennas at the base station. If the signals from the different antennas fade independently, diversity at the receiver is achieved. Therefore, the ratio between the desired signal and the noise plus interference from other base stations can be enhanced. This means that there is less transmission power required to meet the same signal quality as in the single antenna case. The investigations within the scope of this work focus on Space-Time Transmit Diversity concept specified in the UMTS standard. I consider the application of Alamouti's Space-Time Transmit Diversity tevhniques in different scenarios. It's performance is evaluated by the calculation of the Average Error at the receiver depentent on the Signal to Noise Ratio. The performance of this method is compared by means MATLAB simulations.Yayın GSM and GPRS security(Işık Üniversitesi, 2004-09) Güven, Yusuf; Yarman, Bekir Sıddık Binboğa; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıIn this thesis study, today's popular mobile voice (GSM) and data (GPRS) communication technologies (as an intorduction) and their security were studied. GSM arhitecture, key components of the GSM, security fonctions, and confidentialy of the GSM was discussed. The main parts that composed the GSM infrastreucture and their relationships in the system was examined. Some identities related to GSM security were introduced. GSM security functions provide to keep secret the identity of the subscriber, authenticate and outhorize the subscriber. Three security algorithms are used to provide authentication, confidentially, and key generation that are A3, A5, and A8 respecttively. To prevent the eavesdropping on the user data it is necessary to encrypt signaling and traffic channel. Because GPRS system uses GSM's infrastructure, it is meaningful to examine the both system together. GPRS infrastructure, the elements that composed the GPRS, security risks and their solututions were examined. GPRS introduced new elements to GSM system, which are GGSN and SGSN. These elements provide main security issues, handles the security functions, keep track of the location of the mobile and authenticates it. Neverthless interconnections with the other networks and systems cause other security risks. To adress these issues encryption, authentication and hashing algorithms are used.Yayın Implementation of a fixed cellular terminal with mobile phone(Işık Üniversitesi, 2002-09) Tekeş, Coşkun; Yarman, Bekir Sıddık Binboğa; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıThe thesis reports the design and realization of a fixed cellular terminal (FCT) device which works with a mobile phone as a GSM Module. The design is emphasized at the structure not to be complex and suitable to be used in mass production. Before starting our design, our currently available FCT products and their functional properties are studied and the most important and usefull properties are fixed. This design is not only a theorical project, it is also realized as a mass product and take part in the market as a product.Yayın A novel channel estimation algorithm for ultra wideband communication systems(Işık Üniversitesi, 2005) Çağlar, Ekrem; Panayırcı, Erdal; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıUltra WideBand (UWB) is an emerging technology that is currently investigated as one viable solution for high capacity, short range wireless indoor systems. Its robustness in dense multipath environments, low cost and low power implementation together with high bit rates achievable are its unique promising features. However UWB signals occupy extremely large bandwidth and experience different propagation characteristics than conventional narrowband signals. Thus to evaluate the performance of UWB systems, an innotive channel model and corresponding channel estimation algorithm is required. This work is concerned with channel models developed so far for the UWB systems and appropriate channel estimation techniques. In this work the IEEE 802.15.3a channel model which best decribes the propagation of UWB signals is chosen as working model and a novel channel estimation method based on sequence estimation via EM algorithm is derived.
