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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Underwater probe for deep sea exploration : Long range acoustic underwater communication system

Nykvist, Kim January 2020 (has links)
This was a thesis that was commissioned by Researcher Peter Sigray at the Royal Institute of Technology (KTH) in Stockholm and was based on an idea by Professor Thomas Rossby, University of Rhode Island (URI). The idea was to further develop the existing Expendable Bathythermograph (XBT), which has been in use since the 1960s. This by first and foremost replacing existing transfer technology, which involved using a thin copper wire when communicating with the recipient remaining on the ship. The new way in which communication is to take place, is by acoustic signals transmitted from the freely descending probe. The goal is to be able to measure down to greater depth compared to the previous type. The aim is to increase today's in-depth measuring capacity of about 900 meters, down to depth of at least 2000 meters, preferably even deeper. The thesis project was divided into several smaller parts, some of which went on in parallel, while others had to have the preceding portion completed, in order for them to take place, i.e., to begin. Initially – and in parallel during the rest of the thesis work – their were studies of two selected books and a set of documents. This to ensure the understanding of all the concepts to be used during the development of the probe. In parallel with the studies, simulations in the computer program COMSOL Multiphysics began. The model probe geometry and material parameters were programmed. An important task was to implement and verify that the so called Perfectly Matched Layer (PML) performed as expected. This was of crucial importance, as different implementations of the PML turned out to result in different outcomes of the simulations’ data. With the results from Perfectly Matched Layer tests verified, the actual simulations could be initiated. Two different pipes were evaluated; one made of stainless steel and the other made of aluminum alloy. Their proportions were slightly different regarding diameter and length. The simulations led to the makings of plots/diagrams over the Transmission Voltage Response (TVR) over a certain frequency range (3000-17000 Hz). Directivity polar plots were also created for both pipes in the program MATLAB and by using a MATLAB. The actual assessment of the probes began in the latter part of the simulation work. There were several different steps in the process of assembling the probes. Finally, the tests in the water tank at The Defense Research Institute (FOI) could take place. For three days all the simulated results were “put to test.” The results during the tests in the water tank at FOI were promising and the remaining challenges, before a complete probe is developed, are achievable. The hypothesis that initially was set got proven, and it can be argued that the thesis as a whole successfully demonstrated it to be true. The idea of the probe is definitely worth further development, in the making of the new version of the Expendable Bathythermograph.
2

To Kill or Not to Kill : The Moral and Dramatic Potential of Expendable Characters in Role-playing Video Game Narratives

Persson, Louise January 2016 (has links)
Killing in role-playing video games is often a prominent feature. Most of the times, the characters killed are nameless criminals or minions of the true antagonist and if the game wants the player to kill, the player will most probably kill. This research was conducted to see how a dynamic narrative could affect a player’s choice of whether or not to kill expendable adversaries when a choice was provided. Participants played an interactive narrative in two different versions, followed by interviews, to see how narrative consequences and mechanisms for moral disengagement affected the players’ choices. The results showed that the choice of whether or not to kill could be affected if the narrative is dynamic and the non-playable characters reflect upon the choices made. Future studies should be conducted to see how graphics and sound affect the choices, and to see if it might be the mere choice in itself that affects the players the most.
3

PROPULSIVE SMALL EXPENDABLE DEPLOYER SYSTEM (PROSEDS) MISSION AND TELEMETRY SYSTEM OVERVIEW

Kennedy, Paul 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / The National Aeronautics and Space Administration’s (NASA) Marshall Space Flight Center (MSFC) in Huntsville, Alabama will launch the Propulsive Small Expendable Deployer System (ProSEDS) space experiment in late 2000. ProSEDS will demonstrate the use of an electrodynamic tether propulsion system and will utilize a conducting wire tether to generate limited spacecraft power. This paper will provide an overview of the ProSEDS mission and will discuss the design, and test of the spacecraft telemetry system. The ProSEDS telemetry subsystem employs a combination of Commercial Off-The-Shelf (COTS) hardware and launch vehicle telemetry system components to minimize costs as well as power consumption. Several measures were used to aid the conservation of spacecraft power resources. First, the transmitter was modified to limit input power consumption to less that 20 watts while providing approximately two watts Radio Frequency (RF) output power. Secondly, the ProSEDS on board Global Positioning System (GPS) receiver is being used to control input power to the transmitter in order to limit the telemetry operations to occasions when the spacecraft is in proximity to preprogrammed ground station locations.
4

Allowable death and the valuation of human life : a study of people living with HIV and AIDS in Zimbabwe

Machingura, Fortunate January 2016 (has links)
With more than 75% of its population experiencing poverty, Zimbabwe was in 2012 considered one of the world's poorest countries. The country sits at the centre of the global HIV/AIDS epidemic and remains one of the hardest hit countries accounting for 5% of all new infections in sub-Saharan Africa. Zimbabwe's 15% HIV prevalence rate was 19 times the global average by 2012, and the total years of life lost due to premature mortality increased by over 150% between 1990 and 2010 because of HIV/AIDS. This study draws on notions of 'governmentality' to ask how the 'framing' of the value of PLWHA has influenced their treatment by the Zimbabwean government and society. Four questions are posed: first the study asks, in what ways do health policy decision-makers in Zimbabwe frame the value of people living with HIV/AIDS (PLWHA)? Secondly, the study questions the ways in which people not infected by HIV (Non-PLWHA) frame the value of PLWHA. Thirdly, the study turns to PLWHA and asks how they frame their own value. Finally, the study investigates the implications of valuing PLWHA, for their lives, or conversely, their deaths. The study draws upon primary research undertaken through interviews, focus group discussions, observations and document review. While there are some contradictions within and between groups of study participants in the ways they frame the value of PLWHA; the study finds consensus within and between these groups in the manner in which they tend to value PLWHA. Analysing these findings, there are five ways people in Zimbabwe frame the value of PLWHA. Firstly, from a 'citizen' perspective, PLWHA are both legal and political citizens who can identify as equal members of society like other citizens. They have social rights; participate, belong and can access HIV treatment that can reduce risks of death. Secondly, from a 'client' standpoint; PLWHA are customers, gaining access to health services through individual monetary payments or social payments such as Government budget allocations. This introduces a degree of 'rationing', forcing the clients (PLWHA) to behave in ways that increase their chances of receiving services. Those with lower purchasing power struggle to access expensive life-saving anti-retrovirals, thus individual wealth confers value on the lives of the wealthy. Thirdly, framing from a Statistical Representation perspective - through statistics, PLWHA can be used as a means of bargaining for government to gain access to international funding, to increase the chances of survival for PLWHA by bringing services such as antiretroviral therapy (ART). Fourthly, the 'Expendable populations' perspective views subgroups of PLWHA who fail to adhere to norms of behaviour prescribed by the government, including those unable to purchase services, such as the poor and homosexuals, sex workers and prisoners, as populations that may be allowed to die. Finally, the study shows that PLWHA lament the discursive space of technocrats with a counter-narrative of their value in which they emerge not as expendable victims but as victors reframed as an indefatigable population - 'Resiliencers'. PLWHA create a narrative of disobedient materiality, challenging totalising notions of governmentality. This study concludes by considering the relevance in the Zimbabwean context of the concept of 'Allowable Death' as a premature, avoidable death despite consciously crafted narratives that the death happened because nothing could have been done under the prevailing conditions to prevent it.

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