The main aim of using radars in industrial safety system is to detect the presence of target accurately. The conventional methods of radar target detection algorithm such as the Cell averaging constant false alarm rate method (CA-CFAR), Greatest of constant false alarm method (GO-CFAR) and the Smallest of constant false alarm rate method (SO-CFAR) has their own disadvantage when it comes to precise target detection which is a key factor for a safety system. This thesis investigates the above mentioned conventional CFAR algorithms for its pros and cons in target detection and proposes a new and improved method called Cell Evaluation target detection method. The proposed method is shown to mitigate the limitations present and the assumptions made in the conventional target detection method. Further more angular estimation is performed to determine the precise location of the target and the artifacts due to the angular estimation is eliminated by aggregating the detected points from multiple radar modules by linear translation. This gives a better visualization of the target. / Radarteknik kan användas inom maskinsäkerhet (MS) för att detektera skyddsvärda objekt, typiskt människor i arbete nära maskiner. Konventionella metoder för detektering med given frekvens falsk alarm (eng. Constant False Alarm Rate (CFAR)) som baseras på medelvärden, har dock betydande brister. Främst beträffande precision och tillförlitlighet, vilket är centralt för MS. Exempel som studerats i detta examensarbete är “Cell-averaging CFAR” (CA-CFAR), “Greatest of CFAR” (GO-CFAR) samt “Smallest of CFAR” (SO-CFAR). Med målet att förbättra detektionen föreslås även en ny CFAR-metod, vilken benämns ”Cell Evaluation target detection”. I detta arbete visas denna metod undertrycka begränsningar med konventionella tekniker. Den undviker även en del antaganden som inte alltid stämmer i praktiken. Studien inkluderar även skattning av riktning. Det visas hur visualisering av skyddsobjekt kan förbättras, genom att felaktigheter elimineras efter sammanläggning av detektioner från flera radarmoduler efter koordinattransformation.

This thesis was conducted to develop a user interface for the visualization of factory data through HMS Networks' Gateway Communicator. The objective of the project was to enhance decision-making in industrial processes through efficient data transfer and visualization. The project involved the design and implementation of a user-friendly and customizable interface that integrates real-time data from industrial machinery. To achieve these goals, the Angular framework was used in conjunction with HTML, CSS, and TypeScript to create a dynamic and responsive user interface. The methodology included user-centered design, ensuring that the final product not only met technical specifications but was also intuitive for end-users. Among the features implemented were dynamic components that allowed for the visualization of critical data such as temperature and pressure through customizable widgets and dialogue components. The results of the project included successful performance testing, unit tests, and usability tests that ensured the system's effectiveness in visualizing data in a manner understandable to users. The conclusion of the work is that an effective user interface can increase operational efficiency through improved data visualization and interaction, which in turn can lead to more informed decisions in industrial environments. / Detta examensarbete utfördes för att utveckla ett användargränssnitt för visualisering av fabriksdata med hjälp av HMS Networks Gateway Communicator. Syftet med projektet var att förbättra beslutsfattandet i industriella processer med hjälp av visualisering av data. Projektet innefattade design och implementering av ett användarvänligt och anpassningsbart gränssnitt som integrerar realtidsdata från industriella maskiner. För att uppnå dessa mål användes Angular ramverket tillsammans med HTML, CSS och TypeScript för att skapa ett dynamiskt användargränssnitt. Metodiken inkluderade användarcentrerad design, vilket säkerställde att slutprodukten inte bara uppfyllde tekniska specifikationer utan också var intuitiv för slutanvändarna. Bland funktionerna som implementerades finns dynamiska komponenter som tillåter visualisering av kritiska data som temperatur och tryck genom anpassningsbara komponenter. Resultaten från projektet inkluderade ett framgångsrikt prestandatest, enhetstester och användbarhetstest som säkerställde systemets effektivitet i att visualisera data på ett sätt som är begripligt för användarna. Slutsatsen av detta arbete är att ett effektivt användargränssnitt främjar datavisualisering och interaktivitet, vilket i sin tur bidrar till att fatta välinformerade beslut inom industriella miljöer.

Recently, there has been an increasing interest in looking at urban environment as a complex system. More and more researchers are paying attention to the study of the configuration of urban space as well as human social activities within it. It has been found that correlation exists between the morphological properties of urban street network and observed human social movement patterns. This correlation implies that the influence of urban configurations on human social movements is no longer only revealed from the sense of metric distance, but also revealed from topological and geometrical perspectives. Metric distances, topological relationships and angular changes between streets should be considered when applying space syntax analysis to an urban street network. This thesis is mainly focused on the comparison among metric, topological and angular analyses based on three kinds of urban street representation models: natural streets, axial lines and axial segments. Four study areas (London, Paris, Manhattan and San Francisco) were picked up for empirical study. In the study, space syntax measures were calculated for different combinations of analytical methods and street models. These theoretical space syntax accessibility measures (connectivity, integration and choice) were correlated to the corresponding practical human movement to evaluate the correlations. Then the correlation results were compared in terms of analytical methods and street representation models respectively. In the end, the comparison of results show that (1) natural-street based model is the optimal street model for carrying out space syntax analysis followed by axial lines and axial segments; (2) angular analysis and topological analysis are more advanced than metric analysis; and (3) connectivity, integration and local integration (two-step) are more suitable for predicting human movements in space syntax. Furthermore, it can be hypothesized that topological analysis method with natural-street based model is the best combination for the prediction of human movements in space syntax, for the integration of topological and geometrical thinking.

Call number: LD2668 .T4 1985 S54 / Master of Science

Thesis (PhD)--Stellenbosch University, 2015.

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Free-Space Optical (FSO) communication through the terrestrial atmospheric channel offers many benefits in the wireless communications arena, like power efficiency; suitability for secure communications; absence of electromagnetic interference; and potentially very high bandwidth. An optical beam propagating through the atmosphere is subject to optical turbulence. Optical turbulence is a random process that distorts the intensity and phase structure of a propagating optical beam and induces a varying signal at the receiver of an FSO communication link. This phenomenon (usually referred to as scintillation) degrades the performance of the FSO link by increasing the probability of error. In this dissertation we seek to characterize the effects of the scintillation-induced power fluctuations by determining the channel capacity of the optical link using numerical methods. We find that capacity decreases monotonically with increasing turbulence strength in weak turbulence conditions, but it is non-monotonic in strong turbulence conditions. We show that low-density parity-check (LDPC) codes provide strong error control capabilities in this channel if a perfect interleaver is used. Multiple transmit optical beams can be used to reduce scintillation. We characterize the spatial correlation of the atmospheric optical channel and determine a scintillation model for the multiple-beam scheme. With this model we can predict the effective reduction in scintillation as a function of the system design parameters. A Multi-channel FSO communications system based on orbital angular momentum (OAM)-carrying beams is studied. We analyze the effects of turbulence on the system and find that turbulence induces attenuation and crosstalk among OAM channels. Based on a model in which the constituent channels are binary symmetric and crosstalk is a Gaussian noise source, we find optimal sets of OAM states at each turbulence condition studied, and determine the aggregate capacity of the multi-channel system at those conditions. At very high data rates the FSO channel shows inter-symbol interference (ISI). We address the problem of joint sequence detection in ISI channels and decoding of LDPC codes. We derive the belief propagation equations that allow the simultaneous detection and decoding of a LDPC codeword in a ISI channel.

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