TY - THES A1 - Dogotari, Marcel T1 - Hardware Design and RF Performance Evaluation of a Long Range 2.4 GHz Radio Module N2 - Low–power, long–range wireless solutions are needed for transmission of environmental and industrial monitoring data from remote, battery–driven sensors. Chirp spread spectrum (CSS) modulation techniques are able to meet these requirements. A CSS–based radio module was designed to operate in the 2.4 GHz frequency band, whose advantages are worldwide availability, lack of duty–cycle restrictions and a broad spectrum. The module’s power consumption is satisfactory, but its range has to be improved. The accuracy of time-of-flight (ToF) distance estimation, an extra feature of the module, has not been evaluated. Impedance matching, transmission lines and printed circuit board design are among the practical aspects discussed, while ToF ranging and orthogonality of CSS signals are considered from a theoretical point of view. KW - Long–range radio module KW - Printed circuit board design KW - Transmission lines and impedance matching KW - Chirp spread spectrum KW - Time-of-flight ranging Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-2158 ER - TY - THES A1 - Lam, Hoi Ying T1 - Radar Signal Distortion caused by Directional Vibration of a 24 GHz FMCW System N2 - This thesis is an initial attempt to investigate the influence of mechanical vibrations on the 24 GHz FMCW radar developed by IMST GmbH and develop a simple vibration compensation model for the human tracking algorithm. The project objectives are to determine the radar signal distortion caused by vibrations theoretically, conduct simulations to evaluate the effects of vibrations on the human tracking process, and develop a basic model to compensate the disturbing vibrations. The single radar pulse simulations conclude that when the radar is vibrating at a low frequency, the signal would not be distorted if the change of phase of the intermediate frequency is less than half a resolution cell. While the results from the multiple radar pulses simulations reveal that factors like the SNR value, vibrating amplitude and the target’s velocity would influence the human tracking process. The higher the SNR value, vibrating amplitude and target’s velocity, the more the detected ghost targets when there is only one target presence. A signal demodulation method is then proposed which indicate the possibility in reducing the disturbance caused by the vibrations. KW - FMCW Radar KW - Vibration KW - Human Tracking KW - Simulation KW - Compensation Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-2164 ER - TY - THES A1 - Prüm, Moritz T1 - Automated Hyperspectral Field Scanner for Vegetation Monitoring N2 - Vegetation monitoring is an important tool in a variety of fields, e.g. precision agriculture and plants’ phenotyping. The system design of existing non-invasive ground based systems is usually not open-source. Therefore, these systems cannot be reliably modified and thus are not suitable to advanced applications, such as prototyping of new sensors. This thesis describes the development of a ground based hyperspectral monitoring system for use in plant science and sensor testing. A well-documented and automated working prototype has been developed and initial tests show promising results. Further work in system modularity and redundancy is needed. KW - Embedded systems KW - Hyperspectral imaging KW - Low-power design KW - System integration KW - Vegetation monitoring Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-2247 ER - TY - THES A1 - Shrestha, Manjil T1 - Development of a Language Model for Medical Domain N2 - Language models are widely used as a representation of written language in various machine learning tasks, with the most commonly used model being Bidirectional Encoder Representations from Transformers (BERT). It was shown that the prediction quality strongly benefits from language model pre-training on domain-specific data. The publicly available models, though are always trained on Wikipedia, news or legal data, thereby missing the domain specific knowledge about medical terms. In this thesis, we will train a BERT language model on medical data and compare performance with domain-unspecific language models. The dataset used for this purpose is the Non-technical Summaries - International Statistical Classification of Diseases (NTS-ICD) task of classification of animal experiment descriptions into International Statistical Classification of Diseases (ICD) categories. KW - Mult-label classification KW - ICD-10 Codes KW - Fine-tuning KW - German BERT NTS classification KW - Transfer learning Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-7405 ER - TY - THES A1 - Ajitkumar Shah, Karan T1 - Development of Decision-making Model for Cost Optimization of Heat Exchanger on the Basis of Spreadsheet Programs N2 - The current advancements in the field of heat exchangers have expanded their range of applications in many industries. The most important factor while investing in the heat exchanger is sizing them for a particular application. The sizing of a shell and tube heat exchanger is always a challenge, often causing customers to invest in either an oversized or undersized heat exchanger. The purpose of this study is to solve the customer’s conundrum of investing in an appropriate size shell and tube heat exchanger. The objectives of this study were (a) to develop and implement a spreadsheet program for optimization of overall heat transfer coefficient of shell and tube heat exchanger, (b) to determine profitability analysis using the Net Present Value (NPV) method, (c) to analyse the price sensitivity using the Monte Carlo simulation. The iteration and optimization are based on Kern’s method. The user defines the process parameters such as the temperature of hot and cold streams, mass flow rates and fluid densities. The user also assumes the tube related properties. The final sizing of the shell side is determined along with Reynolds number and pressure losses on the shell and tube side. The pressure losses are then converted into the operating cost of the heat exchanger to determine NPV. The Monte Carlo simulation calculates 1000 different NPVs for a given scenario, thus facilitating the user’s crucial decision-making process. This study is probably a first instance to combine preliminary sizing of the shell and tube heat exchanger with price sensitivity analysis using the Monte Carlo method. KW - Shell and tube heat exchanger KW - Cost-benefit analysis KW - Kern’s design method Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-9114 ER - TY - THES A1 - Hammond, Luciano T1 - LIDAR and RADAR Sensors in Passenger Vehicles N2 - Automotive RADAR and LIDAR are two examples of sensor technologies used to observe the environment and detect objects surrounding the host vehicle, in order to enable ADAS. Naturally, the use of sensors in order to enable systems intended to protect and support the driver or improve their comfort entails stringent requirements; not only in terms of performance, but reliability and robustness as well. This has led to the continued development of sensor technologies, with developers seeking to additionally provide more compact and cost-effective alternatives to surrounding sensing; autonomous driving being the end goal, therefore entailing stricter requirements. Although both RADAR and LIDAR sensors are used for the same purpose, i.e. measuring the radial distance towards a target and determining its velocity relative to the host vehicle, they differ with regards to their functionalities, components, operation and various other aspects, leading to individual strengths and weaknesses. For example, RADAR is known for its impressive detection range, whereas LIDAR is known for its enhanced accuracy and resolution. These contrasting characteristics therefore indicate that either sensor may be preferred over the other in certain situations; perhaps in which one may perform better than the other, or due to other factors and aspects. This paper aims to analyse and compare the two sensor technologies and their use in passenger vehicles with respect to these various factors and aspects, in order to provide an insight into different cases in which one may be more suitable than the other. In general, a single sensor cannot definitively achieve all automotive requirements within all situations. Thus, a combination of sensors is recommended, in order to benefit from their individual strengths and ensure continuous system functionality and availability to detect the surrounding environment. KW - ADAS KW - RADAR KW - LIDAR KW - ITS KW - Automotive Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-4276 ER - TY - THES A1 - Vazquez Hernandez, Marcos T1 - Implementation, execution, and analysis of efficiency measurements to be used in the calculation of CO₂ emissions and fuel consumption of heavy-duty vehicles as per Commission Regulation (EU) 2017/2400 N2 - Quick and reliable transport of goods within the European Union is possible, in part, due to the use of heavy-duty vehicles. Whether long-haul routes, or local and urban deliveries, heavy-duty vehicles are crucial for a large part of EU’s economic activity and the number of these vehicles on the road increases every year. However, they also are main contributors to the total greenhouse gas emissions of the road transport sector and play an important role in the total emissions of the European Union. Therefore, it is of great economic and environmental importance to closely monitor emissions and fuel efficiency of heavy-duty vehicles currently on the road and market, forcing manufacturers to reduce emissions from their vehicles and develop more energy-efficient technologies. For this purpose, the European Commission developed the VECTO simulation tool, reducing costs and time necessary for the approval process and monitoring of new vehicles in the EU. While generic values related to the CO₂ emissions and fuel efficiency characteristics of most components of heavy-duty vehicles are provided by the European Commission to use in VECTO simulations, accurate results require actual component testing. With no VECTO specific testing offered by vehicle testing specialists, this thesis aims to conduct an analysis of Commission Regulation (EU) 2017/2400, guideline for the use of VECTO, to identify requirements, develop and implement testing procedures in experimental tests, and validate results to ensure that the requirements of the regulation are met. KW - Drivetrain testing Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-14958 ER - TY - THES A1 - O'Shea, Brendan T1 - Evaluation of Solidworks on how to integrate part preparation for Additive Manufacturing in the CAD modeling process N2 - Solidworks is a CAD software that facilitates the construction of 3D models and drawings to enable production. These systems are usually designed to be used in conjunction with Subtractive Manufacturing (SM) and forming processes. This is due to the enormous portion of world-wide production in which these two processes are used. Because of this, design guidelines are customarily based on the abilities and constraints of conventional manufacturing processes. Additive Manufacturing (AM) replaces these with a new set of advantages and limitations that should be considered to assist in the design of parts. Design for Additive Manufacturing (DfAM) represents a methodology which closely resembles Design for Assembly (DFA) and Design for Manufacturing (DFM), as far as reducing component count and allow for easier manufacturing. The aim of this research is to establish DfAM criteria and to evaluate the core Solidworks software in its ability to support design using these criteria. DfAM criteria is sub-divided into two categories. Product DfAM criteria are those derived from the advantages offered by AM technology, while Process DfAM are those determined by the limitations of the AM technique used. Three example models, each addressing multiple criteria, are created in Solidworks and optimized for printing. Through this process, helpful features in the software are identified and analyzed. Embodiment of these examples by means of Fused Deposition Modeling (FDM) validates these features in an exemplary way and explores the integration of AM design practices in Solidworks. The results of this evaluation will allow further research into CAD support for AM, specifically with respect to Product DfAM. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-13823 ER -