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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

A Framework for the Governance of Information Security

Edwards, Charles Kumar 01 January 2013 (has links)
Information security is a complex issue, which is very critical for success of modern businesses. It can be implemented with the help of well-tested global standards and best practices. However, it has been studied that the human aspects of information security compliance pose significant challenge to its practitioners. There has been significant interest in the recent past on how human compliance to information security policy can be achieved in an organization. Various models have been proposed by these researchers. However, there are very few models that have tried to link human commitment attributes with information security governance of an organization. The research problem of this study was to identify the security controls and mechanisms to govern information security effectively. The proposed model was based on agency theory and comprises a relationship between human commitment variables (ethics, integrity and trust) with security governance variables (structural, relational and process) referred as systemic variables in the research. The resulting correlation is further related with governance objectives (goal congruence and reducing information asymmetry) to hypothesize an effective information security in an organization. The research model proposed was tested employing confirmatory factor analysis (CFA) and structural equation modeling (SEM). There were four models tested in this research. The first model (initial measurement model) comprised human variables linked with relational and the systemic variables linked with goal congruence and information asymmetry. This model could not get through the CFA tests. A modified model comprising human and systemic attributes related with goal congruence and information asymmetry, separately, was taken forward to SEM. This model returned low model fitment scores and hence two alternate models were tested. In the first alternative, the human attributes were related with goal congruence and systemic attributes were linked with information asymmetry. In the second alternative, the relationships of the first alternatives were retained and two alternate relationships were introduced - integrity was linked with information asymmetry and structural was linked with goal congruence. Both models are very close to good model fitment scores. However, the second alternative returned better results and hence, was chosen as the final outcome of the research. The model reflects that human attributes and systemic attributes are fairly independent in an effective information security framework, and drive goal congruence and information asymmetry, respectively. However, integrity is an important human commitment for ensuring information asymmetry and the right organizational structure and roles are important for ensuring goal congruence.
2

The Deployable Wing Structure for the KTH REXUS Free Falling Unit

Ly, Jennifer, Jargalsaikhan, Orgil January 2021 (has links)
With the help of sounding rockets, the Earth’sionosphere can be studied by ejecting cylindrical units thatmeasure various electromagnetic properties while falling. Theseunits are also known as Free Falling Units (FFUs). The goal of thisproject is to turn the FFUs into autonomous gliders by designingdeployable wings. A spring-loaded Scissor Structural Mechanism(SSM) was chosen as the main deploying mechanism. Furthermore,the conceptual wing design was simulated in Siemens NXand a structural analysis was performed in NASTRAN. Finally, aprototype was manufactured to confirm if the SSM would workas intended. Initial simulation results showed great promise withthe proper choice of materials. Due to resource limitations, theprototype could not be compared to the simulation. Based onthe prototype results, the design must be reinforced or alteredto become stronger and more rigid. / Med hjälp av sondraketer kan jordensjonosfär studeras genom att skicka ut cylindriska enhetersom mäter diverse elektromagnetiska egenskaper medan defaller. Dessa enheter är också kända som FFUs (Free FallingUnits). Målet med detta projekt var att förvandla dessa enhetertill autonoma glidare genom att designa utfällbara vingar.En fjäderbelastad saxmekanism valdes som den huvudsakligautfällningsmekanismen. Vidare simulerades den konceptuellavingdesignen i Siemens NX och strukturen analyserades i NASTRAN.Slutligen tillverkades en prototyp för att bekräfta omsaxmekanismen skulle fungera som avsedd. De första simuleringsresultatenvisade sig vara lovande med rätt materialval.På grund av begränsningar i resurser, kunde inte prototypenjämföras med simuleringen. Baserat på prototypresultaten måstedesignen förstärkas eller ändras för att bli starkare och mer styv. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm
3

Design of structural mechanisms

Chen, Yan January 2003 (has links)
In this dissertation, we explore the possibilities of systematically constructing large structural mechanisms using existing spatial overconstrained linkages with only revolute joints as basic elements. The first part of the dissertation is devoted to structural mechanisms (networks) based on the Bennett linkage, a well-known spatial 4R linkage. This special linkage has been used as the basic element. A particular layout of the structures has been identified allowing unlimited extension of the network by repeating elements. As a result, a family of structural mechanisms has been found which form single-layer structural mechanisms. In general, these structures deploy into profiles of cylindrical surface. Meanwhile, two special cases of the single-layer structures have been extended to form multi-layer structures. In addition, according to the mathematical derivation, the problem of connecting two similar Bennett linkages into a mobile structure, which other researchers were unable to solve, has also been solved. A study into the existence of alternative forms of the Bennett linkage has also been done. The condition for the alternative forms to achieve the compact folding and maximum expansion has been derived. This work has resulted in the creation of the most effective deployable element based on the Bennett linkage. A simple method to build the Bennett linkage in its alternative form has been introduced and verified. The corresponding networks have been obtained following the similar layout of the original Bennett linkage. The second effort has been made to construct large overconstrained structural mechanisms using hybrid Bricard linkages as basic elements. The hybrid Bricard linkage is a special case of the Bricard linkage, which is overconstrained and with a single degree of mobility. Starting with the derivation of the compatibility condition and the study of its deployment behaviour, it has been found that for some particular twists, the hybrid Bricard linkage can be folded completely into a bundle and deployed to a flat triangular profile. Based on this linkage, a network of hybrid Bricard linkages has been produced. Furthermore, in-depth research into the deployment characteristics, including kinematic bifurcation and the alternative forms of the hybrid Bricard linkage, has also been conducted. The final part of the dissertation is a study into tiling techniques in order to develop a systematic approach for determining the layout of mobile assemblies. A general approach to constructing large structural mechanisms has been proposed, which can be divided into three steps: selection of suitable tilings, construction of overconstrained units and validation of compatibility. This approach has been successfully applied to the construction of the structural mechanisms based on Bennett linkages and hybrid Bricard linkages. Several possible configurations are discussed including those described previously. All of the novel structural mechanisms presented in this dissertation contain only revolute joints, have a single degree of mobility and are geometrically overconstrained. Research work reported in this dissertation could lead to substantial advancement in building large spatial deployable structures.

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