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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

Utilisation d'identifiants cryptographiques pour la sécurisation IPv6 / Use of crypto based identifiers for IPv6 security

Combes, Jean-Michel 28 September 2012 (has links)
IPv6, protocole succédant à IPv4, est en cours de déploiement dans l’Internet. Il repose fortement sur le mécanisme Neighbor Discovery Protocol (NDP). Celui-ci permet non seulement à deux nœuds IPv6 de pouvoir communiquer, à l’instar du mécanisme Address Resolution Protocol (ARP) en IPv4, mais il apporte aussi de nouvelles fonctionnalités, telles que l’autoconfiguration d’adresse IPv6. Aussi, sa sécurisation pour le bon fonctionnement de l’Internet en IPv6 est critique. Son mécanisme de sécurité standardisée à l’Internet Engineering Task Force (IETF) se nomme Secure Neighbor Discovery (SEND). Il s’appuie à la fois sur l’utilisation d’identifiants cryptographiques, adresses IPv6 appelées Cryptographically Generated Addresses (CGA) et qui sont générées à partir d’une paire de clés publique/privée, et de certificats électroniques X.509. L’objet de cette thèse est l’étude de ces identifiants cryptographiques, les adresses CGA, ainsi que le mécanisme SEND les employant, et leurs réutilisations potentielles pour la sécurisation IPv6. Dans une première partie de cette thèse, tout d’abord, nous posons l’état de l’art. Dans une deuxième partie de cette thèse, nous nous intéressons à la fiabilité du principal mécanisme connu employant les adresses CGA, le mécanisme SEND. Dans une troisième et dernière partie de cette thèse, nous présentons des utilisations des identifiants cryptographiques pour la sécurisation IPv6 / IPv6, next Internet protocol after IPv4, is under deployment in the Internet. It is strongly based on the Neighbor Discovery Protocol (NDP) mechanism. First, it allows two IPv6 nodes to communicate, like the Address Resolution Protocol (ARP) mechanism in IPv4, but it brings new functions too, as IPv6 address autoconfiguration. So, the security of this mechanism is critical for an Internet based on IPv6. The security mechanism standardized by the Internet Engineering Task Force (IETF) is Secure Neighbor Discovery (SEND). It is based on the use of cryptographical identifiers, IPv6 addresses named Cryptographically Generated Addresses (CGA) and generated from a public/private keys pair, and X.509 certificates. The goal of this PhD thesis is the study of such cryptographical identifiers, CGA addresses, as well as SEND using them, and their potential re-use to secure IPv6. In a first part of this thesis, we recall the main features of the IPv6 protocol. In a second part of this thesis, we are interested in the reliability of the main known mechanism using the CGA addresses, SEND. In a third and last part of this thesis, we present different uses of cryptographical identifiers to secure IPv6
2

Risk Management and Logistic Improvement of Oil Handling in Gear Manufacturing

Elassar, Ghada January 2013 (has links)
Nowadays, safety and environmental awareness about the increased industrial accidents have become a critical issue that concerns both, individuals and governmental policies. This leads to higher demands on the manufacturing industry to be safer and more environmentally friendly. Recently, there has been a number of industrial accidents and serious fires in the world that have increased because of using plastic composite IBC containers in industrial manufacturing. And this becomes a common important issue for all manufacturers that strive to improve their environmental performance. The main purpose of this thesis is to investigate different available options of oil fluid storage and transportation in the industry, and to identify the most crucial factors related to each storage and transportation mode. Those factors are investigated and highlighted regarding to their effect on quality, environment and work environment. The thesis also aims to investigate and analyse the hazards associated with oil storage in the plant and in the warehouse and to use risk management strategies in order to identify and mitigate risks in the early stages. The work is carried out at GKN Driveline Köping AB that required a study of the methods used in industry for oil storage and transportation. Therefore the work focuses on identifying suppliers’ different transportation processes including different packaging options. This report includes an explanation of the methodology that is used to perform the task that the company has entrusted, and also contains a review of the comprehensive literature study. The method used to investigate hazards associated with oil transportation and storage is risk management that includes risk assessment tools, FMEA analysis and Ishikawa diagram. FMEA is performed to analyse both, the company’s current process and the process of filling oil by tank trucks regarding quality, environment and work environment. Benchmarking is another analysing tool used to analyse Volvo Power train and GKN Driveline different performances. The empirical findings are analysed by utilizing the JIT philosophy to identify the non value added activities and then determine the inconsistency with JIT philosophy. Kaizen and possible improvements are identified as well, with the help of the visual map VSM. The results that have been achieved are presented and modified according to what suppliers can provide, what the law demands, what the insurance requires and even what fits with the plant structure. The conclusion includes a description of the relation between internal and external logistics and how the synergy between them affects the choice for different transportation processes. It also includes a suggestion for possible improvement regarding logistical costs and transportation costs.
3

Automatiserad Högtryckstvätt

Gorgis, Elias, Lindgren, Peder January 2013 (has links)
Undersökningar och beräkningar av en rengöringsprocess med ibc-containers vid Allemballage har gjorts. En automatiserad lösning har tagits fram där vissa delar har tillhandahållits i förväg som rengöringsverktyg. Uppgiften blev att studera om verktyget klarade av de räckvidder som var avgörande samt att fastsälla om den robot som kunden ville använda sig av kunde utföra uppgiften genom att ta reda på vilket moment som uppstod för att sedan ta fram en simulering av processen i RS. Räckvidden undersöktes dels i RS men även ett presentationsunderlag togs fram. Momentet undersöktes dels praktiskt där man fastställde de krafter som verkade och teoretiskt där man sedan beräknade momentet. Det sista som gjordes var en simulering på hur processen kan se ut då en IRB4600-robot ifrån Abb och rengöringsverktyg utförde en rekonditionering av en IBC. Resultaten har visat att momentet i kortare stunder överstiger det krav som ställs på önskad robot men att verktyget klarar de räckvidder som ställs. Räckvidden och momentet har visat sig vara beroende av varandra då en minskning av räckvidden leder till ett mindre moment, vise versa. Med de undersökningar som gjorts och det resultat som tagits fram är rekommendationen i dagsläget att man bör lägga en beställning på det aktuella rengöringsverktyget. Vidare så anses robot IRB4600 kunna utföra uppgiften som tänkt, mindre justeringar bör då göras vid de ställen som visat sig utgöra det största momentet vid rengöring.
4

An exploration of the impact of interdependence based collaborations (IBC) on small-scale farmers and poverty alleviation

Holeni-Mdhluli, Mikateko January 2013 (has links)
Poverty and food insecurity are common problems among low-income households in developing countries. Innovative interventions in the agricultural sector are regarded as effective in poverty alleviation and therefore food insecurity. Food insecurity is defined by London and Anupindi (2012) as a lack of access to adequate, safe and nutritious food and is closely associated with poverty. It can ultimately be addressed as part of a broader strategy to alleviate poverty, which would include enterprise-led initiatives, inclusive approaches and value chain adjustments. London and Anuipindi (2012) argued that a study hoping to demonstrate the relevance and reliability of understanding the base of pyramid (BoP) as a catalyst to interdependence–based collaboration, would address the level of agribusiness isolation and individualism, to reap the benefits of shared advantage, followed by addressing the interconnected issues of poverty and food insecurity. This study proposes that small scale farmers can benefit from interdependence-based collaborations (IBC) of key role players from the state, private sector and civil society. Consequently, this is a qualitative exploratory study, aiming to seek new insights into the application of inclusive models based on the IBC within the small farm holding, the private sector, civil society and government, and thus their impact on the capacitation of the small-scale farmer and alleviation of poverty. / Dissertation (MBA)--University of Pretoria, 2013. / ccgibs2014 / Gordon Institute of Business Science (GIBS) / MBA / Unrestricted
5

Développement de modules photovoltaïques bifaciaux à haut rendement utilisant le concept i-Cell / Development of high-efficiency, bifacial photovoltaic modules using the i-cell concept

Salinesi, Yves 29 October 2018 (has links)
Les travaux présentés dans cette thèse consistent à concevoir des modules à haut rendement et à bas coûts. Des modules intégrés réalisés à partir de sous-cellules découpées ont été réalisés. Ces sous-cellules sont inspirées de la technologie PERC. La réduction du coût de production en simplifiant le procédé de fabrication et en diminuant la quantité de matériaux utilisés a été étudiée. L’augmentation des rendements a été observée en ouvrant la face arrière des cellules, ce qui leur confère la bifacialité, et en utilisant des moyens performants pour la réalisation des émetteurs. Dans un second temps, l’augmentation de la puissance des modules a été étudiée en s’inspirant de l’i-Cell développée par la société S’Tile pour réduire fortement les pertes résistives traditionnellement observées dans les modules classiques. La même étude a été réalisée à partir de cellules IBC spécialement conçues pour être découpées en sous-cellules et ainsi assemblées en modules. Ces cellules ont été développées pour être compatibles avec des procédés industriels de production de masse, permettant de réduire le coût de production par rapport à des cellules IBC conventionnelles. Les sous-cellules obtenues après découpe ont été connectées pour obtenir des modules photovoltaïques bifaciaux permettant l’obtention de hauts rendements. De cette manière, deux voies possibles sont explorées pour l’amélioration des rendements et la diminution des coûts des modules photovoltaïques. / The work presented here is aimed to produced high-efficiency, low-cost photovoltaic silicon solar modules. Integrated modules have been carried out from laser-cut sub-cells. These cells have been produced using the PERC cell technology. The reduction of production costs have been studied by simplifying the manufacturing processes and by decreasing the quantity of materials used. An increase in efficiency has been observed by opening the rear side of the cells, making them bifacial, and by using advanced means in order to realize the cell emitters. The increase of produced power has been studied by using sub-cells in order to reduce the resistive losses measured in standard modules. The same study has been carried out with IBC solar cells. These cells have been designed to be separated in sub-cells by laser scribing, and to be produced with means compatible with mass production only, thus decreasing the cost. The sub-cells obtained after laser scribing have been connected in order to obtain bifacial photovoltaic modules producing high electrical power. In this way, two possible paths towards high efficiency and low cost modules have been studied.
6

Structural and Functional Analysis of the Caspase –dependent and –independent Domains of the X-linked Inhibitor of Apoptosis Protein in Inflammatory Breast Cancer Tumor Biology

Evans, Myron K. January 2016 (has links)
<p>Inflammatory breast cancer (IBC) is an extremely rare but highly aggressive form of breast cancer characterized by the rapid development of therapeutic resistance leading to particularly poor survival. Our previous work focused on the elucidation of factors that mediate therapeutic resistance in IBC and identified increased expression of the anti-apoptotic protein, X-linked inhibitor of apoptosis protein (XIAP), to correlate with the development of resistance to chemotherapeutics. Although XIAP is classically thought of as an inhibitor of caspase activation, multiple studies have revealed that XIAP can also function as a signaling intermediate in numerous pathways. Based on preliminary evidence revealing high expression of XIAP in pre-treatment IBC cells rather than only subsequent to the development of resistance, we hypothesized that XIAP could play an important signaling role in IBC pathobiology outside of its heavily published apoptotic inhibition function. Further, based on our discovery of inhibition of chemotherapeutic efficacy, we postulated that XIAP overexpression might also play a role in resistance to other forms of therapy, such as immunotherapy. Finally, we posited that targeting of specific redox adaptive mechanisms, which are observed to be a significant barrier to successful treatment of IBC, could overcome therapeutic resistance and enhance the efficacy of chemo-, radio-, and immuno- therapies. To address these hypotheses our objectives were: 1. to determine a role for XIAP in IBC pathobiology and to elucidate the upstream regulators and downstream effectors of XIAP; 2. to evaluate and describe a role for XIAP in the inhibition of immunotherapy; and 3. to develop and characterize novel redox modulatory strategies that target identified mechanisms to prevent or reverse therapeutic resistance. </p><p> Using various genomic and proteomic approaches, combined with analysis of cellular viability, proliferation, and growth parameters both in vitro and in vivo, we demonstrate that XIAP plays a central role in both IBC pathobiology in a manner mostly independent of its role as a caspase-binding protein. Modulation of XIAP expression in cells derived from patients prior to any therapeutic intervention significantly altered key aspects IBC biology including, but not limited to: IBC-specific gene signatures; the tumorigenic capacity of tumor cells; and the metastatic phenotype of IBC, all of which are revealed to functionally hinge on XIAP-mediated NFκB activation, a robust molecular determinant of IBC. Identification of the mechanism of XIAP-mediated NFκB activation led to the characterization of novel peptide-based antagonist which was further used to identify that increased NFκB activation was responsible for redox adaptation previously observed in therapy-resistant IBC cells. Lastly, we describe the targeting of this XIAP-NFκB-ROS axis using a novel redox modulatory strategy both in vitro and in vivo. Together, the data presented here characterize a novel and crucial role for XIAP both in therapeutic resistance and the pathobiology of IBC; these results confirm our previous work in acquired therapeutic resistance and establish the feasibility of targeting XIAP-NFκB and the redox adaptive phenotype of IBC as a means to enhance survival of patients.</p> / Dissertation
7

Achieving Security in Messaging and Personal Content in Symbian Phones

Enany, Ahmed January 2007 (has links)
This thesis describes two proposed schemes that could be used to secure mobile messaging (SMS/MMS) as well as one scheme that could be used to secure mobile content. The security services we considered in securing the mobile messages are confidentiality, authentication, non-repudiation and integrity. We used Identity Based Cryptography in order to secure the mobile messaging and Blowfish algorithm to secure the mobile content. Due to some of the disadvantages imposed by the Identity Based Cryptography, we recommended using it along with the RSA algorithm. The proposed schemes were implemented in java and tested on an actual device, Nokia N70. In addition, we measured the time required by each of the algorithms we used to encrypt/decrypt a certain number of bytes. We found that the time taken by RSA and Blowfish algorithms will not be noticeable by the user. However, since the implementation of the Identity Based Cryptography we used was not meant to run on mobile devices, we encountered a noticeable delay whenever encrypting/decrypting the data using this algorithm. Securing the SMS messages will make it to be considered as one of the proposed means that could be used to conduct m-commerce. In addition, securing the MMS messages and the mobile content will increase the usability and the reliability of the mobile phones especially to the users on the move. / Phone: +46735731360
8

Investigation into a Laser Welded Interconnection Method for Interdigitated Back-Contact(IBC) Solar Cell Modules

January 2019 (has links)
abstract: Interconnection methods for IBC photovoltaic (PV) module integration have widely been explored yet a concrete and cost-effective solution has yet to be found. Traditional methods of tabbing and stringing which are still being used today impart increased stress on the cells, not to mention the high temperatures induced during the soldering process as well. In this work and effective and economical interconnection method is demonstrated, by laser welding an embossed aluminum (Al) electrode layer to screen-printed silver (Ag) on the solar cell. Contact resistivity below 1mΩ.cm2 is measured with the proposed design. Cross-sectional analysis of interfaces is conducted via Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDXS) methods. Typical laser weld phenomenon observed involves Al ejection at the entrance of the weld, followed by Al and Ag fusing together mid-way through the weld spot, as revealed by cross-sectional depth analysis. The effects of voltage and lamp intensity are also tested on the welding process. With the range of voltages tested, 240V seems to show the least process variability and the most uniform contact between Al and Ag layers, upon using an Ethylene-Vinyl Acetate (EVA) encapsulant. Two lamp intensities were also explored with a Polyolefin (POE) encapsulant with Al and Ag layers seen welded together as well. Smaller effect sizes at lamp 2 intensity showed better contact. A process variability analysis was conducted to understand the effects of the two different lamps on welds being formed. Lamp 2 showed a bi-modal size distribution with a higher peak intensity, with more pulses coupling into the sample, as compared to lamp 1. / Dissertation/Thesis / Masters Thesis Materials Science and Engineering 2019
9

Control of 3D-printed Hand Prosthetic via Intra-body Fat Channel Communication

Trollsås, Eric January 2022 (has links)
Intra-Body Communication (IBC) is a prospective technology where human tissue may be used as a signal medium in order to transmit useful data within the human body. Proposed applica- tions of this technology are prosthetics control or implanted device communication, potentially by establishing an Intra-Body Area Network (IBAN), which could further be enhanced by other IoT applications and 5G radio systems. Previous research at Uppsala University has shown the fat tissue to be a promising medium due to its low permittivity and loss tangent. This form of implementation is named Fat-IBC. This thesis aimed to produce a Fat-IBC enabled device, as a proof of concept. This project successfully produced and characterized phantom tissue, produced a basic demonstrator device in the form of a 3D-printed arm prosthetic, and integrated a wireless communication system into the arm prosthetic. The communication system was implemented using Arduino microcontrollers and XBee RF modules, based on the 802.15.4-based ZigBee protocol at 2.45 GHz. Muscle, fat, and skin phantom tissues were produced, with the muscle tissue being similar to other comparable tissue samples, while the fat and skin tissues deviated from such samples. A signal loss transmission test measured a -67 dB loss over 20 cm of fat tissue. Several potential issues with production and measurement were discussed. The arm demonstrator device was also tested by transmitting the control signal across phantom fat tissue, being fully functional through 10cm of tissue, and of limited function across 20cm of tissue.
10

Characterization of monkey fat tissues : To assist their viability for fat intra-body communication as an early step of non-human primate testing (NHP)

Alyounes, Qsai, Razan, Alkari January 2022 (has links)
Fat intra-body communication is a newly proven concept that is built on using human fat tissues as a communication channel for electromagnetic waves inside the body. This allows for two implanted external devices to connect through an intra-body closed-loop communication channel. This concept utilizes the fact that the fat tissues have low dielectric properties and are located between two tissue layers, skin and muscle, which have high dielectric permittivity and high loss tangent so that the signal propagates and confines with lower losses within the fat tissue. In this study, the eligibility of using monkey fat tissues as a communication channel for intra-body communication is being investigated. This comes as a first step in a long process of testing implementing medical devices, mainly prosthetic limbs, on non-human primates using fat-IBC at microwave frequencies. To be able to do that, an experimental characterization of ex-vivo monkey fat, skin, and muscle tissues to explore their dielectric properties compared to those of humans is being carried out. This study of the dielectric properties of monkey tissues is the first of its kind to be carried out on two samples of ex-vivo monkey tissues. Calf tissues have also been investigated in the study to get an insight on the potential differences between human and non-human body tissues in general before doing measurements on monkey tissues. For the measurements, an RF network analyzer and an open-ended coaxial probe method have been implemented. Phantoms that mimic the human tissues have been fabricated to be used as a reference point. The initial investigation demonstrates that calf fat tissues have much higher dielectric properties than human fat tissues. Monkey fat, muscle, and skin tissues showed many similarities to human tissues regarding their dielectric properties. This indicates that monkey tissues can be used for fat intra-body communication. Future numerical and analytical modeling of the monkey tissues needs to be conducted to confirm and strengthen this finding.

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