Browsing by Author "Onen, Denis"

Now showing 1 - 6 of 6
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    Design and Comparative Analysis of FRS Architectures for the AI DCT
    (2013-10-10) Onen, Denis; Dimitrov, Vassil
    Computationally intensive sinusoidal transforms such as the Fast Fourier Transform (FFT) and Discrete Cosine Transform (DCT) play a large role in science and engineering. The DCT has found valuable application in image and video processing. Its broad use has prompted many researchers to seek to improve its computational properties. In the DCT, multiplication by irrational constants has been identified as a source of error, due to the introduction of quantization error. Efforts to overcome this quantization error have led to the relatively recent application of Algebraic Integer (AI) representations, by Dimitrov. The use of AI allows the irrational constants to be encoded, without quantization error. Numbers encoded in AI can be easily operated on by the arithmetic operations of addition, subtraction, and multiplication, all without the introduction of quantization error. A large computational penalty is paid when the AI encoded number, is reconstructed into a single number, using a process known as the Final Reconstruction Step (FRS). This research investigates and develops a large number of novel designs for the FRS, in the application of 2D AI to the 2D DCT. These designs include the application of Multiple Constant Multiplication (MCM) and a substitution method, to reduce the computational complexity of the FRS. These new designs offer a significant improvement in Mean-Squared Error (MSE) and computational complexity, in comparison with standard FRS designs. This research also provides a comprehensive comparative analysis of AI methods versus non-AI methods for the 2D DCT, and finds that non-AI methods are superior to AI in many cases, for the metrics of MSE and computational complexity, despite the significant FRS improvements reported in this thesis. For the case of area-limited designs, this thesis demonstrates the superiority of the AI method over the non-AI method, by the use of a single, multiplexed FRS stage.
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    Leakage Prevention and Detection in Pipelines Utilizing a Wireless Information and Communication Network
    (2018-01-03) Valentin de Oliveira, Thiago; Mintchev, Martin P.; Gemma Lu, Qingye; Onen, Denis; Yadid-Pecht, Orly; Mintchev, Martin P.
    Major environmental concerns have arisen due to a series of pipeline leakage incidents. Several systems have been proposed to identify and locate leakages; however, incidents still persist and pipeline acceptance from the public has become compromised. In order to address the need for early leakage detection, as well as leakage prevention, a novel pipeline system is proposed. This concept builds on the already existing pipe-in-pipe design, by segmenting the pipeline system with segmentation rings and embedding a wireless network in the annular airgap between the two pipe layers. Presence of fluid in the case of a leakage causes degradation of the wireless network. The leak is detected in real time by an external central unit connected to the wireless network, as demonstrated with a 6'8'' experimental pipeline setup. An analysis of the US pipeline system is provided, along with a cost estimate of implementing such technology.
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    Medium-assisted Microwave Telemetry for Directional Drilling Applications
    (2020-09-25) Almeida Costa e Silva, Ingrid; Mintchev, Martin P.; Yadid-Pecht, Orly; Onen, Denis; Fapojuwo, Abraham O.
    The drilling industry has an increasing reliance on sensor telemetry systems in order to improve process efficiency and safety. Typically measured in terms of throughput, telemetry performance is in constant need for improvements for better measurement and logging while drilling tools to be employed to ensure safer and more cost-effective wellbore drilling, particularly in directional drilling applications. Recent works have shown remarkable improvements in telemetry performance via the use of radio frequency (RF)-based telemetry. However, these systems have not been designed to work in water-based environments because of water's high electromagnetic attenuation effect in the microwave band. In this work, I propose and test a new medium-assisted RF-based telemetry system that allows for improved drilling telemetry performance in water-based scenarios. The approach, named microwave telemetry (MWT), makes use of an added propagation medium to allow for improved radio communication via reduced signal attenuation within the communication channel. To test the foundations of the MWT system, I inserted two XBee S2C RF modules into three dielectric rods made out of different dielectric materials. I show that the addition of the rods into a water-based environment significantly increased the throughput and reduced the bit error ratio and packet loss ratio of the system. I also show that different materials presented statistically significant better network performance in accordance with the order of improved electromagnetic properties. These statistically significant (p-value < 0.05) results indicate a path towards which RF-based telemetry systems could be used in water-based drilling environments.
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    Real-Time Wide Dynamic Range Capture and Display System Based on Mantissa-Exponent Representation
    (2019-04-09) Shahnovich, Ulian; Yadid-Pecht, Orly; Onen, Denis; Murari, Kartikeya
    In this work, we present a wide dynamic range (WDR) vision system that is able to capture bright and low light objects in a single frame without being over or underexposed. The data is captured and streamed in real-time (RT) mode from the sensor to a monitor at 60 fps or a PC. The presented system includes: 1) WDR complementary metal-oxide-silicon (CMOS) image sensor design which is able to update the integration time of each individual pixel depending on the ambient light and provide output in a mantissa-exponent format (floating point) [1], [2]. 2) Interface hardware designs including PCBs and HDL drivers required to activate the sensor and all the peripheral components. 3) A tone-mapping algorithm based on a mantissa/exponent representation along with its hardware implementation that allows us to render WDR data on a conventional low dynamic range (LDR) devices [3].
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    Understanding Human Behaviours in Engineering Design to Aid its Teaching and Research
    (2020-09-11) Gress, Gary Robert; Li, Simon; Radford, Scott K.; Wood, David H.; Onen, Denis; Marsden, Catharine C.
    The objective of this thesis is to better understand the process of engineering conceptual design in terms of human abilities and behaviours so as to provide insights and improvements in its practice, education and research. The thesis aims to help educators better guide novice designers towards proficiency by allowing for their natural predispositions, if any, and to contribute towards a common theoretical foundation upon which future design research can be conducted. To do this the thesis seeks to identify and understand those predispositions, and to determine their underlying causes where possible. This necessarily involves an outside-of-design multi-disciplinary approach, and includes several facets. Literature in the fields of child development and neuro-psychology are reviewed for their similarities or possible causative links to designer behaviours already elucidated in an initial design-research literature review. This is followed by a self-observation study of the researcher while undertaking an actual design project, to provide any insights or context and to illuminate any aspects that may require further investigation. That study uncovered the extreme importance of lengthy observation of the physical artifact – and of discussing the artifact with others – to successful outcomes for this designer. It lead to a subsequent extended review of the literature in the fields of memory, visualization and spoken language, which provided key information for the completion of near-identical object-learning and design problem-solving models. These models are shown to explain several design behaviours usually disparaged upon by design educators and researchers; they also provide guidelines for dealing with these behaviours and for design learning and instruction generally. These explanations and guidelines form the key contributions of this research. The research is completed by a series of interviews with practicing designers to discern their design approaches, which are found to align with the published literature, this researcher’s own design approach, and the aforementioned models. Finally, it is also found that the models’ paired tenet of observing and conjecturing, aligning with Simon and Schön’s paradigms of recognition and reflection respectively, is likely an essential or core process of design.