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Commercial navigation in the Greek and Roman worldDavis, Danny Lee 16 October 2012 (has links)
The economic development of Greece and Rome hinged directly on the ability of commercial vessels to transport large volumes of goods across the Mediterranean and Black Sea. Archaeology has revealed the sizes, construction methods and cargos of these ships, but the navigational techniques that were employed to direct them from port to port remain unclear and elusive. In ancient literature, the oft-repeated themes of storm, shipwreck and death at sea led to the popular assumption among scholars that seafarers developed habits to minimize their exposure to this hostile element--hugging the shore to avoid the open sea, putting in at night, sailing only in summer, and using 'seafaring manuals' to help guide their way. While several recent studies have made some strides in overturning this overly simplistic view by highlighting aspects of navigation in certain areas and in certain periods, the 'standard model' lingers in both scholarly and popular imagination. This study offers a comprehensive review of the scattered textual and archaeological evidence pertaining to ancient seafaring and navigation, and a major reinterpretation of ancient commercial navigation in both periods. Chapters 2-3 explore the parameters of the maritime environment (coasts, winds, currents and visibility) and the human responses to them in the form of ships, seasonal rhythms and maritime corridors. Chapters 4 and 5 discuss the ways in which Greek and Roman sailing masters accounted for the fundamental requirements of navigation--the determination of direction, position, speed and distance--using wind roses as a 'compass' and various stars and star groups at night. Chapter 6 treats the question of whether seafarers used written guides or experience, or both, to help determine their position. Chapter 7 explores the historical figure of the sailing master himself and integrates a wide range of evidence to reconstruct the navigational routines of the crews of Alexandrian grain ships during the Roman imperial era. My research concludes that both coastal and open-sea sailing were matters of routine in the commercial sector, that commercial seafarers did indeed sail at night and employ the stars to deduce navigational information, that winter sailing was a widespread practice, and that crews employed navigational strategies to weather storms, usually successfully. / text
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Spacecraft precision entry navigation using an adaptive sigma point Kalman filter bankHeyne, Martin Cornelius, 1973- 28 August 2008 (has links)
Not available / text
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Real Time Procedural Wind Soundscape : The effect of procedural wind soundscape on navigation in virtual 3D spaceÞorsteinsson, Jóhannes January 2015 (has links)
Sound design with the help of procedurally generated sound in video games has seen arise in the last few years given how that method gives us greated freedom in how soundreacts in realtime to the games, and the players. This research looks into if there is anydifference in how procedural sound, in this case procedurally generated wind, affectsthe navigation of players in a three dimensional world, as opposed to static samplebased sound design.
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On-line optical flow feedback for mobile robot localization/navigationSorensen, David Kristin 30 September 2004 (has links)
Open-loop position estimation methods are commonly used in mobile robot applications. Their strength lies in the speed and simplicity with which an estimated position is determined. However, these methods can lead to inaccurate or
unreliable estimates. Two methods are developed in this thesis. The first uses a single optical sensor and can accurately estimate position under ideal conditions and when wheel slip perpendicular
to the axis of the wheel occurs. A second method which uses two optical sensors is developed which can accurately estimate position even when wheel slip parallel to the axis of the wheel occurs. Location of the optical sensors is investigated in order to minimize errors caused by inaccurate sensor readings. Finally, the method is implemented and tested using a potential field based navigation scheme. Estimates of position were found to be as accurate as dead-reckoning in ideal conditions and much more accurate in cases where kinematic violations occur.
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Two novel off-screen navigation techniquesNezhadasl, Mahtab 23 April 2009 (has links)
In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation.
I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom.
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An exploration of the oncology patient navigator role: perspectives of younger women with breast cancerPedersen, Allison E. 08 September 2011 (has links)
Background: One in nine Canadian women will be diagnosed with breast cancer within their lifetime. In Manitoba, an estimated 810 women will be diagnosed with breast cancer in 2011, with approximately 160 of those aged 20 to 50. Younger women diagnosed with breast cancer may have unique needs and challenges due to a variety of factors that include caring for younger children, career demands, or in some cases, family planning. Many women face a heightened sense of vulnerability after their diagnosis which challenges their physical, emotional, and spiritual self as they attempt to navigate through the complexities of the health care system. One approach to alleviate health care systemic challenges has been the establishment of patient navigation programs. To date, the role of the oncology patient navigator has not been examined from the perspectives of patients experiencing the oncology system of care without the services of an established patient navigator. Method: Consistent with the purpose of this study, an interpretive, descriptive qualitative research approach was utilized to describe the role of the oncology patient navigator from the perspectives of younger women aged 20-50 (n=12) diagnosed with an invasive breast cancer within the last three years. Face-to-face interviews were conducted and audio-taped to capture their descriptions of the oncology patient navigator based on their own experiences. Results: The role of the oncology patient navigator includes two facets - personal attributes and essential processual needs – for which the navigator could provide assistance. Conclusion: The results of this study depict the oncology patient navigator’s vital attributes and processual facets based on the perspectives of younger women with breast cancer. This study can be utilized for the purposes of tailoring or expanding current roles in oncology or perhaps cultivating the development of new navigational programs to address the needs of younger women with breast cancer.
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Two novel off-screen navigation techniquesNezhadasl, Mahtab 23 April 2009 (has links)
In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation.
I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom.
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An exploration of the oncology patient navigator role: perspectives of younger women with breast cancerPedersen, Allison E. 08 September 2011 (has links)
Background: One in nine Canadian women will be diagnosed with breast cancer within their lifetime. In Manitoba, an estimated 810 women will be diagnosed with breast cancer in 2011, with approximately 160 of those aged 20 to 50. Younger women diagnosed with breast cancer may have unique needs and challenges due to a variety of factors that include caring for younger children, career demands, or in some cases, family planning. Many women face a heightened sense of vulnerability after their diagnosis which challenges their physical, emotional, and spiritual self as they attempt to navigate through the complexities of the health care system. One approach to alleviate health care systemic challenges has been the establishment of patient navigation programs. To date, the role of the oncology patient navigator has not been examined from the perspectives of patients experiencing the oncology system of care without the services of an established patient navigator. Method: Consistent with the purpose of this study, an interpretive, descriptive qualitative research approach was utilized to describe the role of the oncology patient navigator from the perspectives of younger women aged 20-50 (n=12) diagnosed with an invasive breast cancer within the last three years. Face-to-face interviews were conducted and audio-taped to capture their descriptions of the oncology patient navigator based on their own experiences. Results: The role of the oncology patient navigator includes two facets - personal attributes and essential processual needs – for which the navigator could provide assistance. Conclusion: The results of this study depict the oncology patient navigator’s vital attributes and processual facets based on the perspectives of younger women with breast cancer. This study can be utilized for the purposes of tailoring or expanding current roles in oncology or perhaps cultivating the development of new navigational programs to address the needs of younger women with breast cancer.
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An intelligent differential GPS navigation systemLiu, Langtao January 1997 (has links)
This thesis describes an Intelligent Differential GPS Navigation System developed for a PhD research project. The first part of the work was to apply differential technology to Global Positioning System to locate the current position of the user with an improved positioning accuracy. The essential part of this Differential GPS system is a Differential GPS Reference Station. This DGPS Reference Station includes a DGPS mathematical model and the corresponding algorithms, which calculates the differential correction messages. These messages are then transmitted to a mobile GPS receiver by a radio data link. By using these corrections, the mobile GPS receiver's positioning accuracy can be improved from about 100 m to 4 m. This DGPS Reference station has been used to implement system software for this research. Differential correction algorithms were modified, characteristics of system components were changed, and different digital filters were also applied at different locations to investigate the impact on system performance. Besides all these capabilities which are needed for the research purpose, this DGPS Reference Station has all the standard functions, and can be used as a standard DGPS Reference Station. The second part of the work was to combine this Differential GPS system with a suitable digital map to form a navigation system. A suitable digital map database was chosen and modified, and the content of the map was then reproduced on the mobile GPS receiver's host PC screen. This digital map, combined with the current location of the user, provides the basic navigational information for the user to reach a desired destination. To help the user further and demonstrate the potential use of the system, an intelligent route-planing algorithm that can produce the optimum route automatically was also designed. The system integration was achieved by the design of the mobile navigation unit and the combination of this mobile navigation unit with the constructed DGPS Reference Station. The final system consists of a DGPS Reference Station, a UHF radio data transmitter, a mobile GPS receiver, a digital map system, a route searching and planing algorithm and a UHF radio data receiver. Field trials were carried out to test the system static and dynamic performances. Repeated experiments showed that both the static and dynamic positioning accuracies were within the range of 4 meters. The constructed system is a prototype navigation system which incorporates the basic navigational functions. It is envisaged that this system can be directly used, or further developed to suit a special need, as required. A typical application of the system would be to guide a user to a desired destination. Other examples include: aircraft autolanding control system, car self-driving, taxi fleet control, criminal tracing and personal navigation systems.
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A navigation and automatic collision avoidance system for marine vehiclesMiller, Keith McGowan January 1990 (has links)
Collisions and groundings at sea still occur, and can result in financial loss, loss of life, and damage to the environment. Due to the size and capacity of moden vessels, damage can be extensive. Statistics indicate that the primary cause of accidents at sea is human error, which is often attributed to misinterpretation of the information presented to the mariner. Until recently, data collected from sensors about the vessel were displayed on the bridge individually, leaving the mariner to assimilate the material, make decisions and alter the vessels controls as appropriate. With the advent of the microprocessor a small amount of integration has taken place, but not to the extent that it has in other industries, for example the aerospace industry. This thesis presents a practical method of integrating all the navigation sensors. Through the use of Kalman filtering, an estimate of the state of the vessel is obtained using all the data available. Previous research in this field has not been implemented due to the complexity of the ship modelling process required, this is overcome by incorporating a system identification proceedure into the filter. The system further reduces the demands on the mariner by applying optimal control theory to guide the vessel on a predetermined track. Hazards such as other vessels are not incorporated into this work but they are specified in further research. Further development work is also required to reduce computation time.
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