A novel lidar ceilometer prototype based on divided lens optics has been designed, built, characterised, and tested. The primary applications for this manufacturable ground-based sensor are the determination of cloud base height and the measurement of vertical visibility. First, the design, which was developed in order to achieve superior performance at a low cost, is described in detail, along with the process used to develop it. The primary design considerations of optical signal to noise ratio, range-dependent overlap of the transmitter and receiver channels, and manufacturability, were balanced to develop an instrument with good signal to noise ratio, fast turn-on of overlap for detection of close range returns, and a minimised number of optical components and simplicity of assembly for cost control purposes. Second, a novel imaging method for characterisation of transmitter-receiver overlap as a function of range is described and applied to the instrument. The method is validated by an alternative experimental method and a geometric calculation that is specific to the unique geometry of the instrument. These techniques allow the calibration of close range detection sensitivity in order to acquire information prior to full overlap. Finally, signal processing methods used to automate the detection process are described. A novel two-part cloud base detection algorithm has been developed which combines extinction-derived visibility thresholds in the inverted cloud return signal with feature detection on the raw signal. In addition, standard approaches for determination of visibility based on an iterative far boundary inversion method, and calibration of attenuated backscatter profile using returns from a fully-attenuating water cloud, have been applied to the prototype. The prototype design, characterisation, and signal processing have been shown to be appropriate for implementation into a commercial instrument. The work that has been carried out provides a platform upon which a wide range of further work can be built.

The advent of industry 4.0 has not only brought innovation and automation with it but also new challenges. Automation in industrial settings is advancing at a rapid pace, thus making the modern industrial workplace all the more stimulating. Highly automated robots and machines work alongside humans in settings that seemed fictional some years ago. However, the shift to a smart industry has brought about certain safety concerns regarding whether the current safety systems can keep up with this ever-changing environment. Emergency stop buttons have long been the industry standard when it comes to classic safety precautions. Nevertheless, researchers examine several possibilities on how they can upgrade the already established safety systems. One such practice is to incorporate visibility as part of an emergency safety system. There has already been a proposal to use 2D visibility as an emergency safety protocol which has shown encouraging results. Thus, making a 3D approach as the logical next step. In this thesis work, a 3D visibility emergency stop system is presented, implemented,and tested. To begin with, a small review of how other researchers have tried to solve similar problems is done. Furthermore, several 3D graphics techniques used in the project are introduced and briefly analysed. Then, the implementation of the project is presented, breaking down each component. After the implementation is completed, several tests that aim to profile the program are performed and examined. In addition, the project is compared to the 2D solution that has already been proposed. The findings from the testing show that a 3D visibility approach is a viable and favourable option. The results reveal a promising outcome when it comes to object visibility as well as response swiftness.

How supply chain visibility could benefit the field of supply chain management is well-known, both within academia and among practitioners. However, less is known about the challenges that supply chain visibility may be coupled with, especially when it comes to organisational challenges for a broader market presence where actors may have conflicting incentives. This thesis tries to explore this issue and does so through a case study by analyzing organisational challenges for supply chain visibility to see greater presence in the third-party logistics market. Most importantly, the findings suggest that an ecosystem perspective is necessary inorder to fully comprehend the organisational challenges. By applying an ecosystem perspective, previously known challenges can be better understood by connecting them with market dynamics, and it also revealed previously unknown challenges related to regulatory challenges. The purpose of this thesis is not to provide definitive theory, but rather show the promise of utilizing an ecosystem perspective in the contemporary supply chain visibility field. This could prove helpful within academia as well as for practitioners. / Det är välkänt hur supply chain visibility kan gynna supply chain management, både inom akademin och för yrkesverksamma. Däremot är det mindre känt vilka utmaningar som är förknippade med marknadsetablering av supply chain visibility, särskilt när det gäller organisatoriska utmaningar. Denna uppsats syftar till att utforska dessa utmaningar genom en fallstudie, med fokus främst på de organisatoriska utmaningar som supply chain visibility skulle kunna innebära inom tredjepartslogistik. Den viktigaste insikten från denna studie är att ett ekosystemsperspektiv är nödvändigt för att fullt ut förstå de organisatoriska utmaningarna. Genom att tillämpa ett ekosystemsperspektiv kan tidigare okända utmaningar bättre förstås genom att kopplas samman med marknadsdynamik. Dessutom upptäcktes en ny kategori av utmaningar som tidigare forskning inte har redogjort för, nämligen juridiska utmaningar. Syftet med denna uppsats var inte att skapa ett definitivt ramverk utan att visa möjligheterna med tillämpning av ett ekosystemsperspektiv inom det för närvarande heta ämnet supply chain visibility. Detta kan vara till nytta både för forskare och yrkesverksamma.

No description available.

Vertebroplasty is a new technique in orthopedic surgery for stabilizing fractured vertebra. In this technique acrylic bone cement as a biocompatible material is injected through a cannula inside of vertebra. There are several concerns in this technique that the most serious one is cement leakage out of vertebra. The main reasons are improper viscosity and lack of visibility. Clinicians who practice vertebroplasty use commercial highly concentrated radiopaque acrylic bone cement (more than 25%BaSO[subscript 4] or ZrO[subscript 2]) or a cement with manually added radiopaque agents. High density materials with attenuation under X-ray are good alternatives compared to conventional radiopaque agents (BaSO[subscript 4] or ZrO[subscript 2]) in acrylic bone cement for application in vertebroplasty. In the first part of this study, thermal and rheological properties of modified acrylic bone cement with conventional radiopaque agent (Barium Sulfate, BaSO[subscript 4]) are studied. Additions of barium sulfate are in the form of substitute or excess. In substitute formulation, barium sulfate is replaced with the same weight of powder and liquid to powder ratio kept constant. In the excess formulation, barium sulfate added as excess and liquid to powder ratio decreased. In the second part of this study, high density radiopaque agents are used as alternative radiopacifier. Experimental design technique is used to study the effect of X-ray conditions, concentration, type, and size of radiopaque agents on the visibility of bone cement. The visibility of bone cement was quantified by the measurement of contrast index. In the first project, it was found that the setting time increased with the increase of concentration of radiopacifier in substitute formulation of barium sulfate bone cement. With increase of barium sulfate concentration, excess formulations showed higher residual monomer but for substitute cement, we had a decreasing trend. Acrylic bone cements with excess formulation had higher initial viscosity compared to reference or substitute but the variation of viscosity with time was lower for substitute formulation and cements had higher working time. In the second project, contrast index was the same for barium sulfate, tungsten, and zirconium in the lower voltage but in higher voltage of X-ray lamp, tungsten and zirconium gave higher contrast index. Variation of current in X-ray lamp changed the contrast index of cement slightly compared to the effect of voltage. Bone cement with nano tungsten had higher contrast index compared to the cement with micro size tungsten although micro size zirconium as radiopacifier gave higher contrast index than nano size zirconium.

This thesis concerns the cultural landscape in the Theban area during the Middle Kingdom, under the reign of Montuhotep III. What part he played in the connection of the Theban landscape was studied. The outlook point was the only temple that Montuhotep III founded in the Theban area, looking out over contemporary sites. The visibility in the Theban area during the early Middle Kingdom were studied by using Geographic Information System and interpreted by using phenome-nology. The viewshed analysis showed that three out of six contempo-rary sites were visible from Thoth Hill. This information was then used to interpret the choice of location.

Thesis (MEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / This thesis relates to the successful development of an unmanned terrestrial vehicle (UTV) capable of operating in an obstacle ridden environment. The primary focus of the project is on the specific path planning algorithms. It is shown that specific methods of populating the obstacle-free space can be combined with methods of extracting the shortest path from these popula- tions. Through use of such combinations the successful generation of optimal collision-free paths is demonstrated. Previously developed modular architectures are combined and modified to create a UTV platform which meets all the requirements for implementation of navigational systems and path planning algorithms on board the platform. A two-dimensional kinematic state estimator is developed. This estimator makes use of extended Kalman Filter theory to optimally combine measurements from low cost sensors to yield the vehicle’s state vector. Lateral guidance controllers are developed to utilize this estimated state vector in a feedback control configuration. The entire system is then successfully demonstrated within a simulation environment. Finally, practical results from two days of test runs are provided in both written and interactive form

This project explores banal nationalism from a perspective where the visibility and usage of the US flag as decoration on everyday products in Sweden is problematized. In comparison with the Swedish flag which has a history of being “unwaved” because open nationalism for a long time has been thought of as vulgar in Sweden, the frequent reproduction of the US flag seems to elude a critical discussion on national expressions. The effects of using a national symbol for commercial purposes is therefore theoretically and practically researched. / <p>The full thesis contains copyrighted material which has been removed in the published version. </p>

Cette recherche s’inscrit, à la fois, dans le champ des recherches portant sur l’organisation du temps scolaire et dans celui traitant de l’articulation des enseignements mathématiques entre école et collège. Il s’agit d’une approche transversale, visant à tisser des liens entre temps d’enseignement, culture des professeurs et mémoire didactique. La thèse montre en quoi la possibilité ou non de mobiliser des situations mathématiques nécessitant des recherches longues et des débats, exerce une influence sur les formes prises par l’institutionnalisation des connaissances et, au-delà, sur le rapport aux mathématiques des enseignants. Dans le courant de l’année scolaire 2006-2007, quatre classes de sixième et quatre classes de CM2 ont été observées. La production d’un nombre important d’énonciations différentes de connaissances différentes, a été mise en évidence, entraînant une régulation, sous la forme d’un nombre restreint de connaissances rappelées et/ou institutionnalisées par écrit. On peut qualifier ce double processus, d’extension et de réduction didactique. La réduction didactique assure aux connaissances visées par l’étude une visibilité élective, tout au long du processus d’institutionnalisation. Cette mise en avant de certaines connaissances, liée à un traitement discursif et sémiotique spécifique, a été qualifiée de « visibilité institutionnelle ». L’aptitude de la mémoire didactique à se projeter dans l’avenir comme dans le passé confirme sa dimension prospective et sa capacité à organiser un récit susceptible d’emporter l’adhésion des élèves. / This research is two-fold, taking place in the field of research on the organization of school time and the one focusing on Mathematics teaching organization, both in primary school and middle school. The approach exposed is transversal, forging links between instructional time, teacher culture and didactic memory. The thesis demonstrates how the possibility or not to mobilize mathematical situations, requiring long research and discussions, affects the institutionalization of knowledge shapes and, beyond, teachers’ feeling about Mathematics. In the course of the 2006-2007 school year, four classes of fifth grade and four classes of sixth grade were observed. The production of a large number of different enunciations of various knowledge was highligthed, resulting in a regulation with a limited number of knowledge recalled and / or institutionalized in writing. We can describe this dual process as didactic extension and reduction.Didactic reduction ensures targeted knowledge elective visibility, all along the institutionalization process. Highlighting a specific knowledge is called “institutional visibility”. The ability of didactic memory to project into the future as into the past confirms its prospective dimension and its ability to organize a story that could win students’ support.

This thesis presents the design and development of a hand-held electronic reader, designed to decode conductive patterns printed on a paper substrate. Data read from the patterns, by the reader, is used to trigger events in the digital domain. The reader and associated conductive patterns are devices for linking paper documents with the digital world. The patterns are formed by masking conductive-coated paper with a non-conductive, printed lacquer. The reader is a low cost and ergonomic device, capable of transmitting the embedded data from the conductive paper to the computer. The first reader designed and developed was tethered to a computer by data cable, using the USB communication protocol. The second design was developed further, with transmission of data achieved by replacing the cable with short-range Bluetooth wireless technology. Both devices were designed and developed using embedded systems and low cost electronic components. Additional work was undertaken to optimise the device's mechanical structure, ergonomics and integration of hardware. Alongside the development of the reader, test and development work was carried out to optimise the printed media, in materials and design. User trials demonstrated that the complete printed and reading system was functional, with varied rates of success among participants. Further work is required to improve the conductivity of the coated paper, and the accuracy of the decoding algorithm.