• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 9
  • 5
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 40
  • 9
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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 Multi-Step Resonant Ionization Spectroscopy Technique Using CW Laser Excitation

Liu, Chen January 1988 (has links)
Note:
2

Entwicklung von Algorithmen und Programmen für ein Archivierungs- und Kommunikationssystem zur internetbasierten Verwaltung medizinischer Bilder

Chludov, Sergej. January 1999 (has links) (PDF)
Trier, Universiẗat, Diss., 2000.
3

Dold forntida kunskap : Studie av forntida och nutida ris- och veteodlingar i Kina ur ett hållbarhets- och arkeologiskt perspektiv. / Hidden ancient knowledge : A study of ancient and modern rice- and wheat agriculture in China from a sustainable- and archaeological perspective.

Karlsson, Martin January 2020 (has links)
This essay tries to prove that archaeology as a science, can be useful as a tool for the creation of sustainable agriculture. Case studies of China´s ancient and modern rice and wheat agriculture are used as an example of how archaeology can fulfill this role. Archaeological data were collected for the ancient types of agriculture in China between 4000 BC and 500 AD, with the intension of analysing it using a sustainability perspective. This period had to be extended for the wheat agriculture to 600 AD. To aid this analysis, a definition of sustainable agriculture was made. Using this definition, a decision could be made whether the ancient types of agriculture could be considered sustainable or not and why. The same analysis was made for the modern types of agriculture, to be compared in the coming discussion. None of the agricultural types could be considered sustainable, although the ancient types were quite close to passing the test. What could be learned from the ancient types of agriculture are also included in the discussion. This is done by discussing current problems China faces concerning their rice -and wheat agriculture in comparison with archaeological data about the ancient types. The conclusion is that archaeological data can be useful in a few ways in this matter and archaeology as a science could be useful when developing sustainable agriculture.
4

Aerial and Stratospheric Platforms and Reconfigurable Intelligent Surfaces in Future Wireless Networks

Alfattani, Safwan 16 December 2022 (has links)
Future wireless networks are envisioned to support a wide range of novel use cases, and connect a massive number of people and devices in an energy efficient way. Several key enabling technologies were considered to support this vision including Internet of Things (IoT) networks, aerial and stratospheric platforms, and reconfigurable intelligent surfaces (RIS). In this dissertation, we study different problems related to the integration between these technologies. First, we propose a cost-effective framework for data collection from IoT sensors using multiple unmanned aerial vehicles (UAVs). This is achieved by effcient clustering of the sensors and optimized deployment of cluster heads (CHs). Then, the number of deployed UAVs and their trajectories will be optimized to minimize the data collection flight time. The impacts of the trajectory approach, environment type, and UAVs' altitude as well as the fairness of UAVs trajectories on the data collection process are investigated. Given that IoT nodes might have different priorities and time deadlines, and respecting the limited battery capacity of UAVs, we enhance the data collection framework to account for these practical constraints. First, an algorithm for finding the minimal number of CHs and their best locations is proposed. Then, the minimal number of UAVs and their trajectories are obtained by solving the associated capacitated vehicle routing problem. The results investigate the impacts of the selected trajectory approach, the battery capacity and time deadlines on the consumed energy, number of visited CHs, and number of deployed UAVs. Next, given the energy issue on aerial platforms, we present our vision for integrating RIS in aerial and stratospheric platforms to provide energy-efficient communications. We propose a control architecture for such integration, discuss its benefits and identify potential use cases and associated research challenges. Then, to substantiate our vision, we study the link budget of RIS-assisted communications under the specular and the scattering reflection paradigms. Specifically, we analyze the characteristics of RIS-equipped stratospheric and aerial platforms and compare their communication performance with that of RIS-assisted terrestrial networks, using standardized channel models. In addition, we derive the optimal aerial platforms placements under both reflection paradigms. The obtained results provide important insights for the design of RIS-assisted communications. For instance, given that a HAPS has a large RIS surface, it provides superior link budget performance in most studied scenarios. In contrast, the limited RIS area on UAVs and the large propagation loss in low Earth orbit (LEO) satellite communications make them unfavorable candidates for supporting terrestrial users. Then, motivated by the demonstrated potential of HAPS equipped with RIS (HAPS-RIS), we propose a solution to support the stranded users in terrestrial networks through a dedicated control station (CS) and HAPS-RIS. We refer to this approach as "beyond-cell" communications. We demonstrate that this approach works in tandem with legacy terrestrial networks to support uncovered or unserved users. Optimal transmit power and RIS unit assignment strategies for the users based on different network objectives are introduced. Furthermore, to increase the percentage of admitted users in an efficient manner, a novel resource-efficient optimization problem is formulated that maximizes the number of connected UEs, while minimizing the total power consumed by the CS and RIS. Since the resulting problem is a mixed-integer nonlinear program (MINLP), a low-complexity two-stage algorithm is developed. Finally, given the different applications and various options of HAPS payload, we envision the use of a multi-mode HAPS that can adaptively switch between different modes so as to reduce energy consumption and extend the HAPS loitering time. These modes comprise a HAPS super macro base station (HAPS-SMBS) mode for enhanced computing, caching, and communication services, a HAPS relay station (HAPS-RS) mode for active communication, and a HAPSRIS mode for passive communication. This multi-mode HAPS ensures that operations rely mostly on the passive communication payload while switching to an energy-greedy active mode only when necessary. We illustrate the envisioned multi-mode HAPS, and discuss its benefits and challenges. Then, we validate the multi-mode efficiency through a case study. At the end of the dissertation, several future research directions are proposed including hybrid orthogonal and non-orthogonal multiple access (OMA/NOMA) beyond-cell communications assisted by HAPS-RIS, configuration of RIS units on stratospheric platforms, energy management for HAPS-RIS, and supporting aerial users through terrestrial RIS.
5

Hjälpmedel för att minska vårdkön till Södersjukhusets röntgenavdelning / Aid for Shortening the Waiting List to the X-ray Clinic at Södersjukhuset

Johansson, Samuel, Skärvinge, Emma January 2019 (has links)
Den ökade belastningen på akutmottagningar i Sverige bidrar till ett kraftigare flöde till röntgenavdelningar. Detta leder till en ökad arbetsbelastning för personalen på avdelningen och skulle med hjälp utav en skärm kunna underlättas. Syftet med studien var att se på möjligheter att implementera en sådan lösning på Södersjukhusets röntgenavdelning. Metoden innefattade en arbetsplatsstudie av röntgenavdelningen såväl som en analys av manualer samt intervjuer med personal associerade med sjukhusets olika databassystem, bland annat TakeCare, RIS och PACS. Resultaten visade att en sådan lösning går att finna i TakeCare, dock så skulle framtagningen av denna lösning vara en långdragen och avancerad process. Detta beror främst på de olika krav som ställs på medicintekniska produkter, bland annat på grund av patientdatasäkerhet. / The increasing encumbrance on Emergency Rooms in Sweden contributes to a vigorous flow to theX-ray Clinics. This leads to an increasing work load for the personnel on the X-ray Clinic, and theywould benefit from having a screen that shows the flow of patients from the Emergency Room tothe X-ray Clinic. The purpose of this study was to investigate possibilities to implement such an aidon the X-ray Clinic at Södersjukhuset. The method consisted of an observation of the X-ray Clinicand analyses of manuals and interviews with personnel associated to different database systems,such as TakeCare, RIS and PACS. The results showed that a solution exists in TakeCare. However,the production of this solution would result in a long and advanced process. This is due to the different requirements on medical products, partially because of the law regarding patient data security.
6

Propuesta y evaluación de estrategias para el aprovechamiento y reducción de residuos sólidos generados por una planta química multipropósito

Duarte Soto, Valentina Rebeca January 2016 (has links)
Ingeniera Civil Química / El futuro del planeta requiere que hoy en día exista un uso sustentable de los recursos que dispone, pues de otro modo las generaciones posteriores tendrán condiciones de vida significativamente diferentes a las actuales. Es por esto que surge la inquietud de la realización de proyectos e investigación de nuevas tecnologías que sean sostenibles y ayuden a reducir la huella y el impacto en el medio ambiente. Entre los años 2005 y 2020 la Compañía en donde se realizó este proyecto buscó reducir indicadores, entre los que se encuentran los residuos industriales líquidos (RILes) y residuos industriales sólidos (RISes), con el fin de ser reconocida como una Empresa amigable con el medio ambiente y hacer más atractivo el negocio para inversionistas. Este trabajo busca proponer y evaluar, de manera técnica, económica y ambiental, alternativas para la reducción y manejo de los flujos de salida de RISes en una de las Plantas de la Empresa, considerando como RIS los envases de materias primas que se utilizan en el proceso y las trazas de componente adheridas a estos. Así, este mismo deberá responder la pregunta: ¿Cuál alternativa de aprovechamiento será la más atractiva para la Compañía?, presentando la mejor dados los resultados de las evaluaciones mencionadas, a fin de aumentar el beneficio económico y medioambiental para la Empresa. Tomando en consideración las jerarquías para la gestión de residuos que proponen la Ley General de Residuos, del Ministerio del Medio Ambiente, y la Directriz Corporativa de la Empresa, se definieron los siguientes pasos para encontrar propuestas de estrategias para el aprovechamiento de RISes generados por la Planta: 1) Evitar que el residuo exista; 2) Minimizar la masa del residuo; 3) Encontrar destinos para envase y componente adherido; 4) Encontrar destinos para envase y componente adherido, por separado. Basándose en la clasificación anterior, fue posible encontrar algunas propuestas como por ejemplo, para evitar que el residuo exista: Pedir materia prima a granel o en otro formato; Minimizar la masa del residuo: Tratamiento con microorganismos o solicitar contenedores de mayor tamaño; Destinos posibles para envase y componente adherido: Valorización del residuo o reciclaje con Empresas; Destinos posibles para envase y componente adherido, por separado: Reciclaje con Empresas. Las alternativas fueron evaluadas técnicamente, con la ayuda de expertos, descartando aquellas que no eran seguras para los operadores ni el medio ambiente o que alteraran el proceso productivo de alguna manera. Se realizó un análisis económico proyectado a 10 años y se decidió qué propuestas eran rentables y cuáles debían ser combinadas para que lograran serlo, concluyendo que las mejores opciones (ambiental y económicamente) son solicitar materia prima a granel o la siguiente combinación: comprar envases de mayor tamaño y luego de utilizarlos, soplar las trazas y vender los recipientes a Empresas que reciclan el material de estos, entregando un beneficio económico que varía entre 1.000.000 [CLP] y 30.000.000 [CLP], dependiendo del componente y de la alternativa.
7

Hur tillagning påverkar halterna av toxiska substanser i mat.

Persson, Max January 2015 (has links)
This study has examined how cooking affects the levels of the toxicantsaflatoxin, arsenic, lead, dioxins, cadmium, mercury, perfluorinatedcompounds and polybrominated diphenyl ethers in rice, potatoes and fish.Not every toxicant was examined for all three types of food, they were onlyexamined for those types of food where current levels of the toxicant in thattype of food are relevant from a risk assessment perspective. To determineif there is a danger of negative effects due to the exposure of thesetoxicants from food, articles from the Swedish National Food Agency andother scientific articles have been compiled. A minor experimentalsubstudy was also performed where rice bought in Uppsala was rinsed andboiled in different ways to see if that affected the residue levels of arsenic.The results of this study indicate that the levels of some toxic substancescan be lowered on a dry weight basis by cooking, and that this reduction isdependent on the cooking method used, the properties of the food andtoxin. The levels of cadmium and mercury were generally unchanged bycooking whereas the results for lead and perfluorinated compounds wereconflicting. Cooking can lover the levels of aflatoxin, arsenic, dioxins andpolybrominated diphenyl ethers on a dry weight basis. The effects ofcooking on toxicant levels should be considered when performing riskassessments, but further studies are needed to achieve a better basis for decision-making.
8

Rozvoj třetí role univerzit: regionální specifikum, nebo otázka národní úrovně? Případová studie českých regionů. / The Third Role of Universities: Regional Uniqueness or National Issue? Case Study of Czech Regions

Špaňhel, Miroslav January 2010 (has links)
The role of universities in regional development has changed over the last two decades. Current discussion in literature confronts universities with challenges related to an emergence of a third role, that should universities perform in regional innovation systems. It concerns regionally-oriented activities, through which universities are becoming the leaders of regional economic and social development. This concept is applied to a comparative case study of two different Czech regions, South Bohemia Region and Moravian - Silesian Region. The objective is to verify, if different regional circumstances leads to a different form and intensity of networking between academic and private sector, or whether the main factor influencing the role of the two Czech universities is a specific national context. Key words: universities, partnership with private sector, regional innovation systems, third role
9

Cellular stress induces RIS dependent sleep and ALA dependent sedation via EGF receptor signaling in Caenorhabditis elegans

Konietzka, Jan 05 July 2019 (has links)
No description available.
10

P3 Dystopia: När havet kommer : en retorisk analys / P3 Dystopia: När havet kommer : a rhetorical analysis

Berglund, Anna-Karin, Nguyen, Malin January 2019 (has links)
According to the IPCC sea levels can rise by up to one meter in the next century and maybe even more depending on both individual lifestyle choices and policy making on a societal level. An episode from the Swedish Rafio P3's podcast series, P3 Dystopia, has been investigated as a communication effort to spread knoowledge about the climate issue and its consequences. The episode chosen for this study deals with the sea level rise and its threat on civilizations across the globe. The podcast is part of the Swedish public serive campaign prior to the election to parliament in September of 2018. Because of this, the episode has been examined using classical rhetorical theories to identify what strategies it utilizes to promote sustainable behavior. One of the key purposes of this study is to investigate how the producers describe and dramatize the sea level rise and its aftermath. Due to this the episode was examined through a storytelling perspective considering what basic story design structures it uses. This study is based on research on risk communication about climate change and how they should be communicated to achieve the best possible effect. The research considers emotion regulation straetgies as the missing link in effective communication about climate change. Since early 21st century most of the research conducted on this area has been focused on using fear as a motivator for behavioral change, but in recent years some scientists say that fear is not enough. This study aims to investigate what sort of emotions the podcast episode uses to capture and influence its listeners and in what way these emotions are conveyed.

Page generated in 0.0442 seconds