• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 55
  • 24
  • 22
  • 8
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 136
  • 33
  • 21
  • 19
  • 19
  • 17
  • 12
  • 12
  • 11
  • 10
  • 10
  • 10
  • 10
  • 9
  • 9
  • 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

A millimeter unilateral finline SIS mixer with a wide IF bandwidth

Zhou, Yangjun January 2013 (has links)
Superconductor-Insulator-Superconductor (SIS) tunnel junction mixers are now commonly used in astronomical receivers at (sub)millimeter wavelengths because of their superb sensitivity, high dynamic range and stability of operation. Niobium SIS mixers operating at frequencies well below the super- conducting gap (∼680 GHz) have already achieved quantum limited sensitivity. Therefore to further enhance the receiver sensitivity, increasing the Intermediate Frequency (IF) bandwidth of SIS mixers has became crucial. This thesis focuses on the theoretical modeling, design and experimental verifi- cation of Nb SIS mixers operating around 230 GHz with a wide IF bandwidth of 1–15 GHz. These mixers were designed for a single baseline heterodyne interferometer (GUBBINS), which is being built to observe the Sunyaev-Zel’dovich effect in the Cosmic Microwave Background. The combination of wide IF bandwidth SIS mixers and complex analogue correlators will allow GUBBINS to feature high surface brightness sensitivity, that helps to distinguish the weak SZ effect from the background noise. The SIS mixer detector system was assembled inside the GUBBINS cryostat together with the IF electronics and RF/LO optical systems. Low noise temperatures of around 71 K were then measured in the GUBBINS system. The Nb SIS mixer we have developed uses a unilateral finline and fully integrated planar circuits deposited on a silicon substrate, to couple the electromagnetic radiation from the waveguide into the SIS junction. The finline mixer allows a broad-band RF coupling, an easy integration of the on-chip planar circuits and an easy-to-fabricate mixer block. To achieve a wide IF bandwidth, the output impedance of the SIS mixer was well matched to the input impedance of the amplifier by a multi-stage microstrip circuit. Additionally, the planar circuit of the SIS mixer was also designed to have a small lumped inductance and capacitance. The SIS mixer chip was extensively simulated by rigorous electromagnetic software (HFSS) and the S-parameter was exported to a quantum mixing package SuperMix to produce a full-wave model of the mixer. Experimental testing yielded a best noise temperature of 50 K with an average noise temperature of 75 K over an RF bandwidth of 160 GHz– 260 GHz. We have performed thorough experimental and computational investigation of the IF system in particular the constraints on the bandwidth caused by the lumped element capacitance of the mixer chip and the matching of the output impedance of the mixer to the IF amplifier. Our conclusion is that a bandwidth of 1–15 GHz could be achieved using our mixer design, subject to the performance of the amplifier. Finally, a variable temperature load system was successfully developed and tested inside the cryostat, to avoid the losses from the room-temperature optics. We have showed that the noise temperature of the SIS detector could be reduced by as much as 15 K by testing the mixer using a variable temperature load inside the cryostat.
2

Vývoj Schengenského informačního systému / Development of Schengen Information System

Hamouzová, Helena January 2006 (has links)
Schengenský informační systém působí jako kompenzační nástroj Schengenu. Jedná se o databázi s obrovským množstvím informací, které využívají kompetentní orgány v každodenním provozu. Dnešní SIS funguje s malými úpravami podle pravidel Schengenu z roku 1990, ale protože se postupem času objevují nové hrozby, je také potřeba, aby se SIS novým změnám přizpůsobil. Bylo rozhodnuto o revizi stávajícího SIS a vytvoření nového Schengenského informačního systému druhé generace. Postupně byly předkládány funkce systému, časové plány na implementaci a finanční rozpočty, až nakonec v roce 2005 Evropská komise předložila právní návrhy na spuštění SIS II. Návrhy nebyly orgány EU, ani členskými zeměmi přijaty bez připomínek, a proto se v roce 2006 objevily nové návrhy. Do data odevzdání této diplomové práce se nepodařilo přijmout finální právní texty definující SIS II.
3

Behandlares kunskap om ADHD : En studie om SiS:s behandlingspersonals upplevda och uppskattade ADHD-kunskaper / Professional caregivers knowledge about ADHD : A study about SiS:s professional caregivers experienced and estimated ADHD-knowledge

Andersson, Caroline, Nässing, Carolina January 2009 (has links)
Studiens syfte var att belysa kunskapsläget om ADHD hos behandlare inom SiS samt hur de arbetar med elever/klienter som har ADHD eller ADHD-liknande symtom. Ett ytterligare syfte med studien var att undersöka prevalensen av ADHD inom SiS. För att mäta kunskapsläget har upplevd och uppskattad kunskap undersökts. En kvantitativ metod med strukturerade telefonintervjuer användes. De mest framträdande resultaten var att behandlarna har god kunskap om ADHD men att de ej upplever att kunskapen är tillräcklig. Resultatet visade även att behandlarna i relativt liten utsträckning använder specifika behandlingsmetoder för personer med ADHD samt att personer med ADHD är överrepresenterade inom SiS:s klientel. SiS skriver att de strävar efter att ge elever/klienter kunskapsbaserad vård och behandling som utgår från individens behov och slutsatsen blir därför att SiS med fördel kan satsa på utbildning/vidareutbildning av behandlingspersonal för att ge dem fördjupad kunskap om ADHD och de behandlingsmetoder som har visat god effekt.
4

Tilltalad och tillfrågad : En kvalitativ studie av personalens attityder kring placerade ungdomars delaktighet och inflytande i behandling på SiS ungdomshem Bärby

Uhnbom, Marcus January 2012 (has links)
Studiens syfte var att undersöka personalens attityder kring placerade ungdomars delaktighet i behandling på SiS ungdomshem Bärby. Undersökningen grundas på fem intervjuer med behandlingsassistenter på de tre avdelningar inom institutionen som erbjuder behandling. Utifrån tre frågeställningar har jag sökt att undersöka dessa attityder, eventuella förändringar i dessa över tid samt hur personalen uppfattar yrkesrollens dubbla funktion varpå resultatet analyseras utifrån Harts teorier kring ungas deltagande samt Goffmans beskrivningar av den totala institutionen. Resultatet visar på att behandlingsassistenterna ser ungdomarnas delaktighet och inflytande under placeringen som helt avgörande faktorer för behandlingsresultatet, samtidigt som ett antal hinder för delaktighet beskrivs; främst i arbetet med behandlingsplaner och i kontakten med Socialtjänsten. Den dubbla yrkesrollen bekräftas i resultatet, och informanterna beskriver både vikten av att företräda ungdomarna och hjälpa dem att få fram egna resurser, samtidigt som man fyller en bevakande och gränssättande funktion. Likheterna med Goffmans totala institutioner är, förutom institutionens inneslutande karaktär, inte många. Däremot beskriver personalen många av de svårigheter i relationen mellan personal och ungdom som Goffman visar på i sin studie av 1960-talets institutioner. De informanter som arbetat mer än tio år på institutionen beskriver tydliga förändringar i attityder till ungdomarna, både gällande förhållningssätt och i arbetet med familj och nätverk. Införandet av ett lösningsfokuserat arbetssätt på Bärby beskrivs som den viktigaste enskilda faktorn till förändring
5

Behandlares kunskap om ADHD : En studie om SiS:s behandlingspersonals upplevda och uppskattade ADHD-kunskaper / Professional caregivers knowledge about ADHD : A study about SiS:s professional caregivers experienced and estimated ADHD-knowledge

Andersson, Caroline, Nässing, Carolina January 2009 (has links)
<p>Studiens syfte var att belysa kunskapsläget om ADHD hos behandlare inom SiS samt hur de arbetar med elever/klienter som har ADHD eller ADHD-liknande symtom. Ett ytterligare syfte med studien var att undersöka prevalensen av ADHD inom SiS. För att mäta kunskapsläget har upplevd och uppskattad kunskap undersökts. En kvantitativ metod med strukturerade telefonintervjuer användes. De mest framträdande resultaten var att behandlarna har god kunskap om ADHD men att de ej upplever att kunskapen är tillräcklig. Resultatet visade även att behandlarna i relativt liten utsträckning använder specifika behandlingsmetoder för personer med ADHD samt att personer med ADHD är överrepresenterade inom SiS:s klientel.</p><p>SiS skriver att de strävar efter att ge elever/klienter kunskapsbaserad vård och behandling som utgår från individens behov och slutsatsen blir därför att SiS med fördel kan satsa på utbildning/vidareutbildning av behandlingspersonal för att ge dem fördjupad kunskap om ADHD och de behandlingsmetoder som har visat god effekt.</p>
6

Caractérisation de jonctions S.I.S. dans un récepteur hétérodyne à 33 GHz.

Zaquine, Isabelle, January 1900 (has links)
Th. doct.-ing.--Grenoble 1, 1985.
7

Contextualizing Secure Information System Design: A Socio-Technical Approach

Charif, Abdul Rahim 01 January 2017 (has links)
Secure Information Systems (SIS) design paradigms have evolved in generations to adapt to IS security needs. However, modern IS are still vulnerable and are far from secure. The development of an underlying IS cannot be reduced to “technological fixes” neither is the design of SIS. Technical security cannot ensure IS security. Generations of SIS design paradigms have evolved, all with their own sets of shortcomings. A SIS design paradigm must meet well-defined requirements, yet contemporary paradigms do not meet all these requirements. Current SIS design paradigms are not easily applicable to IS. They lack a comprehensive modeling support and ignore the socio-technical organizational role of IS security. This research introduced the use of action research in design science research. Design science paradigm was leveraged to introduce a meta-design artifact explaining how IS requirements including security requirements can be incorporated in the design of SIS. The introduced artifact CSIS provided design comprehensiveness to emergent and changing requirements to IS from a socio-technical perspective. The CSIS artifact meets secure system meta-design requirements. This study presented a secure IS design principle that ensures IS security.
8

The role of intelligence in securitisation processes : a tool or an agent?

Yakubov, Ikrom January 2017 (has links)
A rapidly expanding literature in International Relations theory researches how certain domestic entities both craft and implement important security policies that have direct implications to either domestic or international environments. The study of the role of the Intelligence Service in securitisation processes best fits into this characterisation, as the Intelligence Service is specially designed to collect, analyse, interpret and disseminate information about domestic and international environments. Moreover, being an entity that has a particularly intimate relationship with political power, Intelligence Services also actively participate in implementing policies, explicitly performing its Instrumentality. This project provides a general framework for conceptualising the role – Agency and Instrumentality – of Intelligence Services in securitisation processes through assessing how the Intelligence Service behaves in various stages and phases of securitisation. In order to achieve the main aim – determining and assessing the Agency and Instrumentality of Intelligence in securitisation, the dissertation adopts a reformulated securitisation theory as an analytical framework. Securitisation is a special form of decision/policy making and implementation process that involves complex activities, like interactions, between a securitising actor and the targeted audience – whose receptivity is vital for the outcome of these interactions. What is known as securitisation is a routine and daily activity for the Intelligence Service in its interactions with the decision/policy makers and it is always prone to initiate securitisation, because securitisation grants Intelligence centrality and an undiminished access to resources. Applying a blended logic of inquiry, the thesis adopts an anti-foundationalist ontology and interpretivist/constructivist epistemology, qualitative methodology and triangulation technique to underpin the theoretical arguments. Moreover, out of the adopted ontological-epistemological positions and methodology, the thesis employs qualitative operationalisation. In order to substantiate the presented analytical claims with factual findings, the dissertation assesses the role of the CIA and SIS-MI6 in recent interconnected securitisation cases. The first pair of cases looks at the role (Agency and Instrumentality) of the CIA and SIS-MI6 in the securitisation of religion based terrorism, the “War on Terror” and the Invasion of Afghanistan. The second pair of cases scrutinises the role of the CIA and SIS-MI6 in the securitisation of Saddam’s regime and the Invasion of Iraq. The results of these case studies demonstrate that the Intelligence Service is one of the key constituents in securitisation processes and performs its Agency or Instrumentality depending on the phases of securitisation.
9

Samband mellan personlighet och arbetstrivsel hos personal inom Statens institutionsstyrelse : En enkätstudie om personlighet och arbetstrivsel / The relation between personality and job satisfaction among employees at Statens institutionsstyrelse

Persson, Junette January 2015 (has links)
The aim of this study was to investigate possible correlations and predictions between job satisfaction and personality factors based on the five factor model (FFM) (Neuroticism, extraversion, openness, agreeableness and conscientiousness) among employees at Statens institutionsstyrelse (SiS). SiS is a demanding workplace and the employee turnover is high. Previous research shows that employee turnover due to low job satisfaction may correlate to personality factors based on FFM. The sample consisted of 121 employees in SiS institutions who responded to an electronic survey. Spearman’s RHO showed that job satisfaction correlated with neuroticism and openness. A multiple regression analysis showed that (N) stress resistance which is an aspect of neuroticism was also a predictor of job satisfaction. The employees had high overall job satisfaction and the conclusion was that the kind of work the subjects have can influence the personality factors that correlate to job satisfaction. The correlations were remarkably weak and it would be interesting to see further research on the correlation between agreeableness and job satisfaction in treating occupations.
10

"Det går inte att ha transungdomar här" : En kvalitativ studie om hur SiS personals föreställningar om genus och sexualitet ges uttryck på de särskilda ungdomshemmen

Linde, Anna January 2018 (has links)
Abstract The study was based on seven interviews with staff members who worked or is working within the compulsory care on the States institutionalboards (SiS) special juvenile homes. The aim was to examine how staff members from SiS uses their fantasies about gender and sexuality and how their fantasies are given expression in relation to the adolescents currently living in the special juvenile homes. The collected information was analyzed with Hirdmans (2001) and Butlers (2007) gender theories. One important conclusion in this study is that the staff members fantasies, to a great extent emanated from a normative perspective. For example, was same-sexed attraction on the institution in many ways unthinkable.

Page generated in 0.0207 seconds