Much work has been done in simulating traditional cellular networks. But with the incoming of ad-hoc network technology, the next generation networks will employ hybrid network architectures using both cellular and ad-hoc networking concepts. We investigate how to create a simulator being able to simulate a hybrid wireless network. This involves setting up a cellular network and an ad-hoc network respectively. However, the most important thing is how to integrate them seamlessly. Fortunately, there has already been a simulator called SIMRA which simulates a UMTS cellular network. Therefore, this thesis work is greatly simplified as how to extend and improve SIMRA to implement a simulator for hybrid wireless network. We selected J-sim as the developing platform for our simulator and our development was greatly based on the wireless package provided by the latest version of J-sim. To evaluate the new simulator, different resource allocation algorithms were run against it and the results were compared to those generated by earlier extensions to SIMRA under the same simulation settings. It showed that the resource allocation algorithms behaved similarly under the hybrid wireless network environment. Nevertheless, there are some discrepancies in behaviors of algorithms used for evaluation that still need to be studied.

This study concerns machine-to-machine (M2M) applications that use smartcards. More specifically,The Subscriber Identity Module (SIM) smart card is used for the purpose of monitoring a continuousnetwork connection between a host device and a server. Multicom Security is a security company thatoffers several secure communication connection services (e.g. payment transactions, alarm signals). Themonitoring of these connections is carried out with continuous heart-beat messages sent from thedevice to a server. Today they provide this heart-beat service through logic in their own manufactureddevices, but they have a desire to place the logic on a SIM card in order to be able to move such serviceswith this card and not with a device. Such services can then also be offered on devices not necessarilymanufactured by Multicom Security.The work consisted of investigation of current telecommunication standards, papers regardingsmartcard applications and the current monitoring service, in order to consider possible solutions toimplement a proof of concept of such solution and evaluate it. One aspect of the study was to checkwhether the implemented solution was general and would work in different mobile equipments and alsoto determine the limitations of such smartcard applications.Three solutions were considered for implementation of which one was successfully implemented andtested. The successful heart-beat application was developed using a network subscription enabled JavaCard smart card and using SMS as bearer for the heart-beat messages. By evaluating the solution withbasic tests of functionality, robustness, performance and compatibility the solution was considered to begeneral and compliant with most new mobile equipments. The evaluation was performed in realenvironment with the application running on an actual SIM card with network subscription tested indifferent mobile devices such as cell phones, built-in communication modules and alarm control panels.An alternative solution based on GRPS instead of SMS was also realized but the tests could not becarried out completely due to lack of access to the SIM card implementation by the card provider.

This dissertation presents the findings of a generic model aimed at providing secure communication with remote computers via the Internet, based on smart cards. The results and findings are analysed and presented in great detail, in particular the behaviour and performance of smart cards when used to provide the cryptographic functionality. Two implemented models are presented. The first model uses SSL to secure the communication channel over the Internet while using smart cards for user authentication and storage of cryptographic keys. The second model presents the SSH for channel security and smart cards for user authentication, key storage and actual encryption and decryption of data. The model presented is modular and generic by nature, meaning that it can easily be modified to accept the newer protocol by simply including the protocols in a library and with a minor or no modification to both server and client application software. For example, any new algorithm for encryption, key exchange, signature, or message digest, can be easily accommodated into the system, which proves that the model is generic and can easily be integrated into newer technologies. Similarly, smart cards are used for cryptography. Two options are presented: first the smart cards only store the algorithm keys and user authentication, and secondly, smart cards are used for storing the algorithm keys, user authentication, and actual data encryption or decryption, as the requirement may dictate. This is very useful, for example, if data to be transferred is limited to a few bytes, then actual data encryption and decryption is performed using smart cards. On the other hand, if a great deal of data is to be transferred, then only authentication and key storage are performed with smart cards. The model currently uses 3DES with smart card encryption and decryption, because this is faster and consumes fewer resources when compared to RSA. Once again, the model design is flexible to accommodate new algorithms such as AES or IDEA. Important aspects of the dissertation are the study and analysis of the security attacks on smart card use. Several smart card attack scenarios are presented in CHAPTER 3, and their possible prevention is also discussed in detail. AFRIKAANS : Hierdie verhandeling bied die bevindinge van 'n generiese model wat daarop gemik is om veilige kommunikasie te voorsien met 'n afstandsrekenaar via die Internet en op slimkaarte gebaseer. Die resultate en bevindings word ontleed en breedvoerig aangebied, veral die gedrag en werkverrigting van slimkaarte wanneer hulle gebruik word om die kriptografiese funksionaliteit te voorsien. Daar word twee geïmplementeerde modelle aangebied. Die eerste model gebruik SSL om die kommunikasiekanaal oor die Internet te beveilig terwyl slimkaarte vir gebruikerbekragtiging en stoor van kriptografiese sleutels gebruik word. Die tweede model bied die SSH vir kanaalsekuriteit en slimkaarte vir gebruikergeldigheidvasstelling, sleutelstoor en werklike kodering en dekodering van data. Die model wat aangebied word, is modulêr en generies van aard, wat beteken dat dit maklik gewysig kan word om die jongste protokolle te aanvaar deur bloot die protokolle by 'n programbiblioteek met geringe of geen wysiging van beide die bediener- en kliënttoepassingsagteware in te sluit. Byvoorbeeld, enige nuwe algoritme vir kodering, sleuteluitruiling, handtekening of boodskapbondeling kan maklik in die stelsel gehuisves word, wat bewys dat die model generies is en maklik in jonger tegnologieë geïntegreer kan word. Slimkaarte word op soortgelyke wyse vir kriptografie gebruik. Daar word twee keuses aangebied: eerstens stoor die slimkaarte slegs die algoritmesleutels en gebruikergeldigheidvasstelling en tweedens word slimkaarte gebruik om die algoritmesleutels, gebruikergeldigheidvasstelling en werklike datakodering en –dekodering te stoor na gelang van wat vereis word. Dit is baie nuttig, byvoorbeeld, wanneer data wat oorgedra moet word, tot 'n paar grepe beperk is, word die eintlike datakodering en – dekodering uitgevoer deur slimkaarte te gebruik. Andersyds, indien 'n groot hoeveelheid data oorgedra moet word, word slegs geldigheidvasstelling en stoor met slimkaarte uitgevoer. Die model gebruik tans 3DES met slimkaartkodering en –dekodering omdat dit vinniger is en minder hulpbronne gebruik vergeleke met RSA. Die modelontwerp is weer eens buigsaam om nuwe algoritmes soos AES of IDEA te huisves. Nog 'n belangrike aspek van die verhandeling is om die sekuriteitaanvalle op slimkaartgebruik te ondersoek en te ontleed. Verskeie slimkaartaanvalscenario's word in Hoofstuk 3 aangebied en die moontlike voorkoming daarvan word ook breedvoerig bespreek. / Dissertation (MEng)--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / unrestricted

The waves traveling on the surface of the world’s oceans carry atremendous amount of energy. The ability to convert this energy forhuman use has the potential to help solves the worlds energy problem. Adirect-drive linear generator point absorber is a wave energy converter(WEC) that aims to reduce the complexity of the overall system andshelter the most vulnerable parts of the system by placing them on theseabed. This concept builds around the buoy moving up and down indifferent sea-states which leads to a correlating vertical movement of thestroke in the generator resulting in the conversion of mechanical energyto power. This report aims to explore the possibility to use the open codeWEC-Sim to model the Uppsala University direct-drive linear generatorWEC in extreme sea states and to identify the resulting extreme loads. Theconstructed WEC-Sim model constrained the buoys motion in heave andsurge and limited its range of motion by modeling the generators upperend-stop spring. Simulations were run for different sea-states and theresulting forces on the system were analyzed. The peak line force for thedifferent sea states was calculated and compared to previous studies. Theresults validated the model as they showed a good correlation for mostsea-states. It was only for larger significant wave heights that there was adivergence compared to the results in previous studies.

This work investigates the problem of transfer from simulation to the real world in the context of autonomous navigation. To this end, we first present a photo-realistic training and evaluation simulator (Sim4CV)* which enables several applications across various fields of computer vision. Built on top of the Unreal Engine, the simulator features cars and unmanned aerial vehicles (UAVs) with a realistic physics simulation and diverse urban and suburban 3D environments. We demonstrate the versatility of the simulator with two case studies: autonomous UAV-based tracking of moving objects and autonomous driving using supervised learning. Using the insights gained from aerial object tracking, we find that current object trackers are either too slow or inaccurate for online tracking from an UAV. In addition, we find that in particular background clutter, fast motion and occlusion are preventing fast trackers such as correlation filter (CF) trackers to perform better. To address this issue we propose a novel and general framework that can be applied to CF trackers in order incorporate context. As a result the learned filter is more robust to drift due to the aforementioned tracking challenges. We show that our framework can improve several CF trackers by a large margin while maintaining a very high frame rate. For the application of autonomous driving, we train a driving policy that drives very well in simulation. However, while our simulator is photo-realistic there still exists a virtual-reality gap. We show how this gap can be reduced via modularity and abstraction in the driving policy. More specifically, we split the driving task into several modules namely perception, driving policy and control. This simplifies the transfer significantly and we show how a driving policy that was only trained in simulation can be transferred to a robotic vehicle in the physical world directly. Lastly, we investigate the application of UAV racing which has emerged as a modern sport recently. We propose a controller fusion network (CFN) which allows fusing multiple imperfect controllers; the result is a navigation policy that outperforms each one of them. Further, we embed this CFN into a modular network architecture similar to the one for driving, in order to decouple perception and control. We use our photo-realistic simulation environment to demonstrate how navigation policies can be transferred to different environment conditions by this network modularity.

Result of my work is make device for logging visitors or game players. I arranged to make two devices, web pages and communication protocol between server and devices. Graphical device will have graphical display with HDMI input, Raspberry main board, NFC reader, camera and GSM module. Second device will have microcontroler ATMEGA644, NFC reader, 2-4 line text display and optional GSM module. Both device will communicate with server via GPRS. Server can change configuration of devices and colecting logs

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A study of the frequency response and gain of Solid-state the Impact-ionization Multiplier (SIM). The SIM generates current gain via impact ionization also known as avalanche gain. The SIM provides low noise amplification from an arbitrary current source. In the case of this study, current sources consisted of photodiodes optimized for a particular wavelength of light. The SIM is fabricated from silicon and enjoys the low noise, low carrier transit time advantages of conventional silicon impact ionization devices while amplifying current from a photodiode of a different material. This is advantageous because ideal detection and multiplication regions cannot always be grown on the same wafer. Furthermore a photodiode fitted to a SIM allows absorption and multiplication regions to be independently optimized. The SIM exhibits a current dependant input resistance. This resistance in combination with field effects from the SIM collector is the limiting factor in the frequency response of the SIM. Frequency response is improved to the extent that this floating voltage at the input can be minimized. Higher AC gains are realized in the device with the incorporation of 3-dimensional geometries. These improvements allow for improved device breakdown and reduced space-charge resistance at high input currents. Frequency response can also be improved by increasing the current flowing into the SIM, this current is most often in the form of DC current such that it can be filtered off at a the output and not interfere with the input signal.

A method of lensless, single pixel imaging is presented. This method, referred to as MAS-IPSII, is theoretically capable of resolutions as small as one quarter of the wavelength of the imaging light. The resolution is not limited by the aperture of any optic, making high resolutions (including subwavelength) feasible even at very large (greater than a meter) distances. Imaging requires only flat optics and a coherent source, making it a good candidate for imaging with extreme wavelengths in the UV and x-ray regimes. The method is demonstrated by the imaging of various test targets. Both real and complex imaging (i.e. holography) is demonstrated.

No description available.