Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2013 / Markets for manufactured products are characterized by a fragmentation of the market (with regards to size and time), and by shorter product cycles. This is due to the occurrence of mass customization and globalization. In mass customization, the same basic products are manufactured for a broad market, but then consumers are given the liberty to choose the “finishing touches” that go with the product. The areas that manufacturers now compete for are higher quality products, low cost and timely response to market changes. Appropriate business strategies and manufacturing technologies must thus be used to implement these strategic dimensions. The paradigm of Reconfigurable Manufacturing System (RMS) has been introduced to respond to this new market oriented manufacturing environment. The design of RMS allows ease of reconfiguration as it has a modular structure in terms of software and hardware. This allows ease of reconfiguration as a strategy to adapt to changing market demands. Modularity will allow the ability to integrate/remove software/hardware modules without affecting the rest of the system. RMS can therefore be quickly reconfigured according to the production requirements of new models, it can be quickly adjusted to exact capacity requirements as the market grows and products change, and it is able to integrate new technology. In this research project, real-time, open controller is designed and developed for Reconfigurable Manufacturing Tools (RMTs). RMTs are the basic building blocks for RMS. Real time and openness of the controllers for RMT would allow firstly, for the modular design of RMTs (so that RMTs can be adapted easily for changing product demands) and secondly, prompt control of RMT for diagnosability.

published_or_final_version / Transport Policy and Planning / Master / Master of Arts

Approved for public release, distribution is unlimited / Despite the increase in the demand for high speed Internet services, the last-mile solutions currently available neither are inexpensive enough to attract the majority of the population, nor are they available in low density populated areas. This thesis examines Fixed Broadband Wireless (FBW) as an alternative technology to the current last-mile solutions. The analysis shows that LMDS and MMDS are the most promising emerging FBW technologies and that they are able, by utilizing microwave radio as their fundamental transport medium and using high modulation schemes, to provide digital two-way voice, data, video and Internet services. The thesis shows that both technologies are constrained by free space loss and line-of-sight impairments with rain absorption being the most significant cause of attenuation in the LMDS case, while vegetation and multipath fading play a significant role mostly in the MMDS case. Additionally, it is shown that there is a positive association between the data rate achieved and the level of influence due to Additive White Gaussian Noise (AWGN). Based on the analysis and using the coverage areas, the total capacity, the achieved data rates, the weather and line-of-sight limitations as well as the cost as the most important criteria, it is concluded that LMDS is a preferable solution for enterprise end-users in densely populated urban areas outside the reach of fiber networks, while MMDS targets residential end-users in rural or suburban areas that are not able to receive service through high-speed wireline connections. / Lieutenant Junior Grade, Hellenic Navy

Après l'entrée dans l'ère du numérique, la consommation vidéo a évolué définissant de nouvelles tendances. Les contenus vidéo sont désormais accessibles sur de nombreuses plateformes (télévision, ordinateur, tablette, smartphone ... ) et par de nombreux moyens, comme les réseaux mobiles, les réseaux satellites, les réseaux terrestres, Internet ou le stockage Blu-ray par exemple. Parallèlement, l'expérience utilisateur s'améliore grâce à la définition de nouveaux formats comme l'Ultra Haute Définition (UHD), le « High Dynamic Range » (HDR) ou le « High Frame Rate » (HFR). Ces formats considèrent une augmentation respectivement de la résolution, de la dynamique des couleurs et de la fréquence d'image. Les nouvelles tendances de consommation et les améliorations des formats imposent de nouvelles contraintes auxquelles doivent répondre les codeurs vidéo actuels et futurs. Dans ce contexte, nous proposons une solution de codage vidéo permettant de répondre à des contraintes de codage multi-formats, multi-destinations, rapide et efficace en termes de compression. Cette solution s'appuie sur l'extension Scalable du standard de compression vidéo « High Efficiency Video Coding » (HEVC) définie en fin d'année 2014, aussi appelée SHVC. Elle permet de réaliser des codages scalables en produisant un unique bitstream à partir d'un codage sur plusieurs couches construites à partir d'une même vidéo à différentes échelles de résolutions, fréquences, niveaux de qualité, profondeurs des pixels ou espaces de couleur. Le codage SHVC améliore l'efficacité du codage HEVC grâce à une prédiction inter-couches qui consistent à employer les informations de codage issues des couches les plus basses. La solution proposée dans cette thèse s'appuie sur un codeur HEVC professionnel développé par la société Ateme qui intègre plusieurs niveaux de parallélisme (inter-images, intra-images, inter-blocs et inter-opérations) grâce à une architecture en pipeline. Deux instances parallèles de ce codeur sont synchronisées via un décalage inter-pipelines afin de réaliser une prédiction inter-couches. Des compromis entre complexité et efficacité de codage sont effectués au sein de cette prédiction au niveau des types d'image et des outils de prédiction. Dans un cadre de diffusion, par exemple, la prédiction inter-couches est effectuée sur les textures pour une image sur deux. A qualité constante, ceci permet d'économiser 18.5% du débit pour une perte de seulement 2% de la vitesse par rapport à un codage HEVC. L'architecture employée permet alors de réaliser tous les types de scalabilité supportés par l'extension SHVC. De plus, pour une scalabilité en résolution, nous proposons un filtre de sous-échantillonnage, effectué sur la couche de base, qui optimise le coût en débit global. Nous proposons des modes de qualité intégrant plusieurs niveaux de parallélisme et optimisations à bas niveau qui permettent de réaliser des codages en temps-réel sur des formats UHD. La solution proposée a été intégrée dans une chaîne de diffusion vidéo temps-réel et montrée lors de plusieurs salons, conférences et meetinqs ATSC 3.0. / After entering the digital era, video consumption evolved and defined new trends. Video contents can now be accessed with many platforms (television, computer, tablet, smartphones ... ) and from many medias such as mobile network or satellite network or terrestrial network or Internet or local storage on Blu-ray disc for instance. In the meantime, users experience improves thanks to new video format such as Ultra High Definition (UHD) or High Dynamic Range (HOR) or High Frame Rate (HFR). These formats respectively enhance quality through resolution, dynamic range and frequency. New consumption trends and new video formats define new constraints that have to be resolved by currents and futures video encoders. In this context, we propose a video coding solution able to answer constraints such as multi-formats coding, multi­destinations coding, coding speed and coding efficiency in terms of video compression. This solution relies on the scalable extension of the standard « High Efficiency Video Coding » (HEVC) defined in 2014 also called SHVC. This extension enables scalable video coding by producing a single bitstream on several layers built from a common video at different scales of resolution, frequency, quality, bit depth per pixel or even colour gamut. SHVC coding enhance HEVC coding thanks to an inter-layer prediction that use coding information from lower layers. In this PhD thesis, the proposed solution is based on a professional video encoder, developed by Ateme company, able to perform parallelism on several levels (inter-frames, intra-frames, inter-blocks, inter-operations) thanks to a pipelined architecture. Two instances of this encoder run in parallel and are synchronised at pipeline level to enable inter-layer predictions. Some trade-off between complexity and coding efficiency are proposed on inter-layer prediction at slice and prediction tools levels. For instance, in a broadcast configuration, inter-layer prediction is processed on reconstructed pictures only for half the frames of the bitstream. In a constant quality configuration, it enables to save 18.5% of the coding bitrate for only 2% loss in terms of coding speed compared to equivalent HEVC coding. The proposed architecture is also able to perform all kinds of scalability supported in the SHVC extension. Moreover, in spatial scalability, we propose a down-sampling filter processed on the base layer that optimized global coding bitrate. We propose several quality modes with parallelism on several levels and low-level optimization that enable real-time video coding on UHD sequences. The proposed solution was integrated in a video broadcast chain and showed in several professional shows, conferences and at ATSC 3.0 meetings.

Two related image processing problems are addressed in this thesis. First, the problem of identification of 3-D objects in real time is explored. An algorithm to solve this problem and a hardware system for parallel implementation of this algorithm are proposed. The classification scheme is based on the "Invariant Numerical Shape Modeling" (INSM) algorithm originally developed for 2-D pattern recognition such as alphanumeric characters. This algorithm is then extended to 3-D and is used for general 3-D object identification. The hardware system is an SIMD parallel processor, designed in bit slice fashion for expandability. It consists of a library of images coded according to the 3-D INSM algorithm and the SIMD classifier which compares the code of the unknown image to the library codes in a single clock pulse to establish its identity. The output of this system consists of three signals: U, for unique identification; M, for multiple identification; and N, for non-identification of the object. Second, the problem of real time image compaction is addressed. The quad tree data structure is described. Based on this structure, a parallel processor with a tree architecture is developed which is independent of the data entry process, i.e., data may be entered pixel by pixel or all at once. The hardware consists of a tree processor containing a tree generator and three separate memory arrays, a data transfer processor, and a main memory unit. The tree generator generates the quad tree of the input image in tabular form, using the memory arrays in the tree processor for storage of the table. This table can hold one picture frame at a given time. Hence, for processing multiple picture frames the data transfer processor is used to transfer their respective quad trees from the tree processor memory to the main memory. An algorithm is developed to facilitate the determination of the connections in the circuit.

Abstract not available

Thesis (M.S.) -- Mississippi State University. Department of Aerospace Engineering. / Title from title screen. Includes bibliographical references.

University of Macau / Faculty of Science and Technology / Department of Computer and Information Science

Effective construction management involves real-time decisions regarding the progress of specific activities, the location of materials and equipment, and the construction site safety. The decision making process can be improved using real-time positioning technologies such as Radio Frequency Identification Device (RFID) systems, Global Positioning System (GPS), and Ultra Wide Band (UWB) sensors. While the GPS is not applicable to indoor positioning and RFID tags cannot provide a fully automated system for position location, the characteristics of UWB systems make this technology a strong candidate for a fully automated positioning system in an indoor construction environment. This thesis presents a comprehensive study of the performance of UWB systems in a controlled laboratory environment and in an institutional construction site in Waterloo, Canada as well as for a particular safety application. A primary objective of the research was to establish the accuracy of real-time position location under various conditions, including the effect of different construction materials (e.g., wood and metal), and to analyze changes in the accuracy of position location as construction progresses and the indoor environment physically evolves. Different challenges faced in implementing such a system in an active construction environment are addressed. Based on a statistical analysis of laboratory data, and considering the construction site experience, the reliability of the UWB positioning system for the aforementioned environments is discussed. Furthermore, an automated safety system is proposed using the real-time UWB positioning technology. Based on the error modeling of the UWB position location, an optimum alarming algorithm is designed for the proposed safety system and the reliability of such system is evaluated through a statistical analysis.

Timing of ordering of inventory items is of very great importance in Materials Requirement Planning. Uncertainties in timing can have an adverse effect on the system performance. Most often the lead time variation contribute to timing uncertainties; and their effects are reflected in added costs. Lead time error effects are investigated in this thesis. The study attempts to estimate the effects through some relevant costs, and their variations across the lot sizing rules. The hypotheses for this study are 1) Between any two lot sizing rules, there will be a significant difference in error coats due to combined effect of purchased lead time error and manufacturing lead time errors; 2) Relative cost performance of lot sizing rules in MRP is influenced by the lead time errors; 3) There will be a difference in error cost between lot for l o t rule and least total cost rule even with single source of lead time variation. To carry out the study a MRP programme was developed, in FORTRAN 77 with provisions to include the lot sizing rules while exploding the structure. The lot sizing rules used in the study are Lot for Lot, Silver and Meal heuristics, Wagner-Whitin algorithm, Least total cost, Least unit cost and Part Period balancing. A simulation model is developed using GPSS/PC, to test the hypotheses. An hypothetical production situation with three end items, each with a different product structure is designed. In addition, a master production schedule and a job shop are also structured. Appropriate distributions are assumed for both manufacturing lead times and purchase lead times. These provide the stochastic variables in the simulation experiments. A series of experiments were carried out with the model to investigate into the variations of costs amongst lot sizing rules. Results of the simulation experiments prove that there are costs associated with lead time errors in MRP. These error costs vary significantly with different lot sizing rules. It is also found that the resultant error costs vary significantly even with a single source of lead time variation. Least unit cost rule gives the beat performance having least error costs. Lot for Lot rule has shown the worst performance amongst the lot sizing rules considered. Other interesting results have emerged out of the study.