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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

Analysis of the Radiation Environment on Board the International Space Station Using Data from the SilEye-3/Alteino Experiment

Larsson, Oscar January 2014 (has links)
This thesis presents an analysis of the radiation environment on board the Russian section of the International Space Station (ISS) using data from the SilEye-3/Alteino experiment. As part of the analysis the efficiency and response of the SilEye-3/Alteino detector was studied. The relative nuclear abundance is generally in agreement with expected results. The presence of odd Z nuclei is significantly increased when compared with measurements outside the ISS. However, in ISS-y (Starboard-Ports) and z (Nadir-Zenith) directions an underabundance of carbon and oxygen nuclei is seen, whereasin x (Forward-Aft) there seemes to be an overabundance. One possible explanation is the absence of high-Z material in the ISS module wall for y and z . Whereas in x, most of the main body of the ISS is in front of the detector and the amount of high-Z material (i.e. aluminium) is large. The nalysis of fragmentation of iron into a range of secondary nuclei (15≤Z ≤25) indicates an aluminium hull equivalent thickness of 8-9 cm in y- and z-directions. For x the aluminium hull equivalence amounts to about 17 cm. Flux, LET, dose and dose equivalent rates present a clear anisotropy in the different orthogonal directions of the ISS, with rates consistently lower in x. This effect is more pronounced for the heavy-ion component (LET &gt;50 keV/μm). Measureddose rates vary from 25 μGy/day to 75 μGy/day, depending on location, orientationand configuration of the detector. The dose equivalent varies from 50 μSv/day toalmost 470 μSv/day.The shielding effect of the polyethylene amounts to 25-37% dependent on loca-tion and orientation inside the ISS. The majority of the reduction occurs duringpassages through the SAA. A Geant4 comparison with the Phits simulations code have been preformed as an initial survey into the treatment of hadronic physics for heavy ions in Geant4. / <p>QC 20140521</p>
2

A critical study of information system strategy formation in a public sector context

Horton, Keith S. January 2000 (has links)
This thesis comprises a critical examination of Information System Strategy (ISS) formation in a public sector context, namely the Police Service in Scotland. Despite the apparent importance attached to ISS, and the proliferation of many methods to assist those engaged in ISS formation, the practice of ISS formation remains comparatively ill-understood. The concepts of strategy and power can be viewed as being closely linked. Using theory based accounts of power, we put forward a multi-dimensional conceptualisation of power as an aid to organisational analysis of ISS formation. Consequently, the focus of this work is not only a detailed investigation into ISS formation practice, but also one in which we evaluate the way in which a multi-dimensional conceptualisation of power affects our understanding of ISS formation practice. This research is based upon six longitudinal case studies of ISS formation in the Police Service. Data collection involved a number of methods: in-depth semi-structured interviews, informal conversation, participation, collection of documentation produced within the case study settings, and collation and analysis of documentary materials from secondary sources. The abstraction of several themes from a cross-case comparative analysis of issues has led to the development of a conceptual framework which underpins our contribution to knowledge: namely, a means of understanding ISS formation as micro-political activity, based upon an ongoing process of construction and reconstruction of social reality. This in turn can be considered as being based upon individual mental constructs, which in turn are influenced by the themes identified. Our framework has been developed as an epistemological device to aid thinking about ISS formation, rather than as a representation of what an ISS formation process is. Implicit in the framework is the contention that ISS formation reflects power relations; however, the practical difficulties in researching power issues should not be underestimated. Several areas for further research arising from this thesis are discussed.
3

Microbial stress in rock habitats

Bryce, Casey Catherine January 2015 (has links)
Micro-organisms are the most abundant and diverse form of life on Earth. Their ability to tolerate stress has enabled them to colonise many inhospitable environments. Microbial processes alter the chemistry of the environment which has left a lasting mark on the geological record. On the other hand, microbial life is heavily influenced by environmental conditions. Indeed, the history of the Earth is shaped by the co-evolution of microbial and geological processes. This thesis explores how micro-organisms are influenced by their environment, with particular reference to microbial rock habitats. Rock habitats are an interesting system to understand the inter-relationship between microbial life and it's environment as they are relatively simple and very common. Rock-dwelling communities are also exposed to numerous stresses such as surface UV exposure, desiccation, temperature fluctuations, low nutrient availability or toxicity from elements leached from the rocks themselves. Three specific aspects of microbial stress in rock environments are investigated here: 1) The use of rocks as a shield from surface UV radiation stress, 2) The microbial response to chemical changes during water-rock interactions, 3) The effect of simultaneous limitation of more than one nutrient. The first uses exposure facilities aboard the International Space Station to provide empirical evidence that colonisation of the early land masses by phototrophs was not inhibited by high surface UV radiation. The latter studies use quantitative proteomics to investigate the cellular response of a heterotrophic bacterium to nutrient deficiency and element leaching, two common stresses in rock habitats. Together these results further our understanding of the relationship between micro-organisms and rocks, both today and over geological time.
4

Plánování operací solárních panelů na ISS / Planning Solar Array Operations on the ISS

Jelínek, Jan January 2014 (has links)
This work focuses on the problem of planning solar array operations on the International Space Station. The goal is to find a viable orientation for ten joints which attach panels to the station. These orientations and modes must satisfy various constraints and the final schedule should also take into account certain preferences. This is a task suitable for automated planning and scheduling, but new technologies are gaining very slowly in the field of the human spaceflights. In this work we will analyze the current solution of this problem and then we will propose a new algorithm that will exploit techniques of automated planning and scheduling. In the contrast with the original greedy algorithm, the suggested algorithm initially finds any solution and then tries to improve it by optimazing partial objective functions. Due to the size of the search space, the search attempts are limited by the time limit. Powered by TCPDF (www.tcpdf.org)
5

Företagsförvärv : Integration som en kritisk framgångsfaktor

Andersson, Marcus, Fagerlund, Mikael January 2005 (has links)
<p>Denna magisteruppsats behandlar företagsförvärv, med särskild fokus på integrationen av det förvärvade företaget. Intressant med denna typ av förvärv är att den möjliggör en tillväxthastighet som inte är möjlig vid organiskt tillväxt.</p><p>Uppsatsens syfte är att utreda hur företag planerar och agerar vid förvärv av små och medelstora företag och hur en rad olika faktor påverkar förvärvet och integrationen i organisationen.</p><p>Arbetet bygger på litteraturstudier och empirisk data inhämtad genom i huvudsak intervjuer som utförts med representanter för ett företag med stor erfarenhet av företagsförvärv, ISS Sverige.</p><p>Slutsatser som kan dras är att den övergripande förvärvsprocessen är ett tämligen standardiserat fenomen och de faktorer som påverkar företagsförvärv är många. Integrationsprocessen skiljer sig mellan olika typer av förvärv, och processen och motivet med förvärvet har betydelse för huruvida förvärvet kan anses lyckat. Något som också framkommit under denna uppsats, är att det finns problem med att utvärdera huruvida integreringen av det förvärvade företaget varit lyckad eller ej.</p>
6

Företagsförvärv : Integration som en kritisk framgångsfaktor

Andersson, Marcus, Fagerlund, Mikael January 2005 (has links)
Denna magisteruppsats behandlar företagsförvärv, med särskild fokus på integrationen av det förvärvade företaget. Intressant med denna typ av förvärv är att den möjliggör en tillväxthastighet som inte är möjlig vid organiskt tillväxt. Uppsatsens syfte är att utreda hur företag planerar och agerar vid förvärv av små och medelstora företag och hur en rad olika faktor påverkar förvärvet och integrationen i organisationen. Arbetet bygger på litteraturstudier och empirisk data inhämtad genom i huvudsak intervjuer som utförts med representanter för ett företag med stor erfarenhet av företagsförvärv, ISS Sverige. Slutsatser som kan dras är att den övergripande förvärvsprocessen är ett tämligen standardiserat fenomen och de faktorer som påverkar företagsförvärv är många. Integrationsprocessen skiljer sig mellan olika typer av förvärv, och processen och motivet med förvärvet har betydelse för huruvida förvärvet kan anses lyckat. Något som också framkommit under denna uppsats, är att det finns problem med att utvärdera huruvida integreringen av det förvärvade företaget varit lyckad eller ej.
7

MINERAÇÃO DE DADOS APLICADA A CLASSIFICAÇÃO DOS CONTRIBUINTES DO ISS. / DATA MINING APPLIED TO THE CLASSIFICATION OF THE TAXPAYERS OF THE TOWN OF GOIÂNIA.

Piccirilli, Tiago Levergger 23 April 2013 (has links)
Made available in DSpace on 2016-08-10T10:40:18Z (GMT). No. of bitstreams: 1 TIAGO LEVERGGER PICCIRILLI.pdf: 1547203 bytes, checksum: e65b171ba35efb72a84100fe0a5088d9 (MD5) Previous issue date: 2013-04-23 / The Public Administration is responsible for the institution, receiving and control of taxes paid by taxpayers. This feature is indispensable to maintenance of its administrative structure and establishment public policies. To improve the control performed by the administration, it s necessary to invest in new technologies since the inspection department constantly receives large data movement economic and regularization of taxpayers. The current computational resources store information with a larger human perception of manipulation and knowledge extraction. In this context, appears in science an area called data mining, specific to extract unknown patterns and knowledge through databases. This study aimed to develop a model to classify taxpayers Tax Services (ISS) which showed some irregularity, with resources and techniques of data mining. The study was performed in the city of Goiania in finance secretary specifically of the Department of Revenue, covering the scenario presented in the year 2011. Among the models built with decision tree algorithm, presented as a result, the classification of irregular contributors with a hit rate of 92,03%. / A administração pública é responsável pela instituição, recebimento e controle de tributos pagos pelos contribuintes. Este recurso é imprescindível para manutenção de sua estrutura administrativa e estabelecimento de políticas públicas. Para aperfeiçoar o controle realizado pela administração é necessário investimento em novas tecnologias, visto que o departamento de fiscalização recebe constantemente inúmeros dados da movimentação econômica dos contribuintes e de regularização cadastral. Os recursos computacionais atuais armazenam informações com capacidade superior à condição humana de manipulação e extração de conhecimento. Nesse contexto, surge na ciência uma área denominada Mineração de Dados, especifica para extrair conhecimento e padrões desconhecidos por meio de bases de dados. Este trabalho apresenta um modelo para classificar os contribuintes do Imposto Sobre Serviços de Qualquer Natureza (ISS) que apresentaram alguma irregularidade, de posse dos recursos e técnicas da mineração. O trabalho foi realizado no Município de Goiânia na Secretaria de Finanças especificamente no departamento de Arrecadação, abrangendo o cenário apresentado no ano de 2011. Entre os modelos construídos com algoritmo de árvore de decisão, apresentou como resultado, a classificação dos contribuintes irregulares com um índice de acertos de 92,03%.
8

Making All The Data Available Some Of The Time In Very Large Telemetry Volume Space Applications

Cook, David B. 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / What do you do when your downlink telemetry needs outstrip your downlink bandwidth capability? The telemetry needed to support construction and operation of the largest, most complex engineering project ever undertaken, the International Space Station (ISS), already requires utilization of the full capacity of the downlink S-band capacity, yet there are additional systems and capabilities still to be added by NASA and the International Partners. The ISS Command and Telemetry Team has developed a method of swapping packets of telemetry that are intended for special operations, while simultaneously sending essential systems telemetry and less critical telemetry that is needed on a continuous basis. To support this attempt to “make available all of the data at least some of the time” the team developed concepts for grouping telemetry into families that would always be selected as a group and then created a set of metadata associated with these groups. This metadata is pre-defined to support automated selection and scrubbing of telemetry to correspond to major upgrades in the command and control software for the ISS. The new process will at least double the effective S-band downlink bandwidth. It will also provide automated selection, scrubbing, reporting and verification of telemetry selections.
9

Surface Characterization of Heterogeneous Catalysts Using Low Energy Ion Scattering Spectroscopy Combined with Electrochemistry

Axnanda, Stephanus R. 2009 December 1900 (has links)
Fundamental studies of heterogeneous catalysis were performed and presented in this dissertation to gain a better understanding of heterogeneous catalytic reactions at a molecular level. Surface science techniques were employed in achieving the goal. Low energy ion scattering spectroscopy (LEISS) is the main surface science technique which will be used in all the studies discussed throughout this dissertation. The main objectives of LEISS measurements are to: 1) obtain the information of surface composition of heterogeneous catalysts from the topmost layer; 2) observe the effects of reaction conditions on the surface composition of heterogeneous catalysts. The surface composition and morphology of Au-Pd clusters bimetallic model catalysts supported on SiO2 were characterized using LEISS, infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). It is observed that relative to the bulk, the surface of the clusters is enriched in Au. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts. Fundamental studies of heterogeneous catalysis were performed and presented in this dissertation to gain a better understanding of heterogeneous catalytic reactions at a molecular level. Surface science techniques were employed in achieving the goal. Low energy ion scattering spectroscopy (LEISS) is the main surface science technique which will be used in all the studies discussed throughout this dissertation. The main objectives of LEISS measurements are to: 1) obtain the information of surface composition of heterogeneous catalysts from the topmost layer; 2) observe the effects of reaction conditions on the surface composition of heterogeneous catalysts. The surface composition and morphology of Au-Pd clusters bimetallic model catalysts supported on SiO2 were characterized using LEISS, infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). It is observed that relative to the bulk, the surface of the clusters is enriched in Au. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts.
10

An interdisciplinary approach to the conceptual design of inhabited space systems

Osburg, Jan. January 2002 (has links)
Stuttgart, Univ., Diss., 2002.

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