<p>Research in engineering design assumes that data flows smoothly among different designers within a product realization process. This assumption is not valid in many scenarios, including when designers partner with a future competitor or when designers search for potential collaborators is hampered by an inability to share sensitive data. This information asymmetry among designers has an adverse effect on the outcomes of the product realization process. Designers need a secure yet collaborative design process that enables them to overcome these information-related risks borne from collaborators participating in their product realization process. Existing cryptographic techniques aimed at overcoming these risks are computationally intensive, making them unsuitable for heavy engineering computations such as finite element analysis (FEA). FEA is a widely used computation technique in several engineering applications, including structural analysis, heat transfer, and fluid flow. In this work, we developed a new approach, secure finite element analysis (sFEA), using which designers can perform their analysis without revealing their confidential design data to anyone, including their design collaborators even though the computed answer depends on confidential inputs from all the collaborators. sFEA is a secure, scalable, computationally lightweight, and cloud-compatible. In addition to sFEA, we developed prototypes and demonstrated that the computational framework within sFEA is general enough to be applied to different stages of the product realization process.</p>

In my master's thesis I start fromthedescriptionofthebasics and thebeginningsofsteganography, itsmethods and purposes. Detaileddescriptionof BMP fileswithhidden data follows. A filestructureisanalysedintothesmallestdetails to avoiddamagingfilewhilehiding. At thesametime to make profit oftheinformationincluded in a fileheader in the most effectiveway. Anotheraimwas to explain a principalofsteganographicalmethoditself, usedforhiding data into BMP file. Based on these findings, a programmeconceptwasdesigned and consequentlythatprogrammewas made. Itcarriesoutthehiding and revealing data intothe image files. Directionsfor use are made to thisprogramme and thereisalso a demo ofthefeaturesdescribingeach step. At the end ofmymaster's thesis anattentionispaid to thoseinfluencesthatcanbelimitingforthismethod. Exceeding these limitswouldlead to breakingthesteganographicalmethod, whichmeansrevealingthehidden data.

The diploma thesis aims on the matter of data hiding (steganography) in audio records. It describes general steganographic principles and aims further on the specifics of data hiding in audio records and also aims on the LSB steganographic technique and suitability of different types of audio records to be used with this technique. The thesis also describes a laboratory exercise focused on steganography in audio records and influence of related aspects on the final audio record which contains secret data. Further, the thesis describes a program that was created especially for the laboratory exercise, from the design, functional as well as implementation-related view. Within the exercise, students will be able to examine how the amount of data to be hidden in the audio record and different ways of data hiding will affect quality of the resulting audio record, and therefore they can become more familiar with the matter of steganography based on the LSB method used in audio records.

This diploma thesis deals with hiding data in the Internet traffic. It contains a description of the law interception. Various possibilities of hiding data are mentioned. The practical part of this thesis consists of an application that hides the data of HTTP and HTTPS protocols in a fake VoIP call. The application consists of two parts: a client and a server. Data transmitted between the client and the server parts are masked as multimedia data of the VoIP call. When a user or Internet server does not transmit any data, random data are transmitted between client and server parts in order to simulate the VoIP call. Then, the thesis focuses on detection of the attack.

To securely communicate information between parties or locations is not an easy task considering the possible attacks or unintentional changes that can occur during communication. Encryption is often used to protect secret information from unauthorised access. Encryption, however, is not inconspicuous and the observable exchange of encrypted information between two parties can provide a potential attacker with information on the sender and receiver(s). The presence of encrypted information can also entice a potential attacker to launch an attack on the secure communication. This dissertation investigates and discusses the use of image steganography, a technology for hiding information in other information, to facilitate secure communication. Secure communication is divided into three categories: self-communication, one-to-one communication and one-to-many communication, depending on the number of receivers. In this dissertation, applications that make use of image steganography are implemented for each of the secure communication categories. For self-communication, image steganography is used to hide one-time passwords (OTPs) in images that are stored on a mobile device. For one-to-one communication, a decryptor program that forms part of an encryption protocol is embedded in an image using image steganography and for one-to-many communication, a secret message is divided into pieces and different pieces are embedded in different images. The image steganography applications for each of the secure communication categories are discussed along with the advantages and disadvantages that the applications have over more conventional secure communication technologies. An additional image steganography application is proposed that determines whether information is modified during communication. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Computer Science / unrestricted

<p>Data embedding tools such as barcodes are very popular nowadays but not aesthetically pleasing. In this research, we propose a watermarking scheme and an image-based surface coding scheme using the grid points as fiducial markers and the shifted points as data-bearing features. Detecting and aligning point grids play a fundamental role in these applications. Joint determination of non-grid points and estimation of non-linear spatial distortions applied to the grid is a key challenge for grid alignment. We modify a SIFT-based surface feature detection method to eliminate as many spurious feature points as possible and propose a grid alignment algorithm that starts from a small nearly regular region found in the point set and then expands the list of candidate points included in the grid. Our method is tested on both synthetically generated and real samples. Furthermore, we extend some applications of the surface coding scheme to 3D space, including hyper-conformal mapping of the grid pattern onto the 3D models, 3D surface feature detection, and 3D grid points alignment. </p> <p>A document routing system is crucial to the concept of the smart office. We abstract it as an online class-incremental image classification problem. There are two kinds of classifiers to solve this problem: exemplar, and parametric classifiers. The architecture of exemplar-based classification is summarized here. We propose a one-versus-rest parametric classifier and four different updating algorithms based on the passive-aggressiveness algorithm. An adaptive thresholding method is also proposed to indicate the low-confidence prediction. We test our methods on 547 real document images that we collected and labeled and high cumulative accuracy is reported. </p>

With the increasing use of the Internet several problems have arisen regarding the processing of electronic documents. These include content filtering, content retrieval/search. Moreover, document security has taken a centre stage including copyright protection, broadcast monitoring etc. There is an acute need of an effective tool which can find the identity, location and the time when the document was created so that it can be determined whether or not the contents of the document were tampered with after creation. Owing the sensitivity of the large amounts of data which is processed on a daily basis, verifying the authenticity and integrity of a document is more important now than it ever was. Unsurprisingly document authenticity verification has become the centre of attention in the world of research. Consequently, this research is concerned with creating a tool which deals with the above problem. This research proposes the use of a Quick Response Code as a message carrier for Text Key-print. The Text Key-print is a novel method which employs the basic element of the language (i.e. Characters of the alphabet) in order to achieve authenticity of electronic documents through the transformation of its physical structure into a logical structured relationship. The resultant dimensional matrix is then converted into a binary stream and encapsulated with a serial number or URL inside a Quick response Code (QR code) to form a digital fingerprint mark. For hiding a QR code, two image steganography techniques were developed based upon the spatial and the transform domains. In the spatial domain, three methods were proposed and implemented based on the least significant bit insertion technique and the use of pseudorandom number generator to scatter the message into a set of arbitrary pixels. These methods utilise the three colour channels in the images based on the RGB model based in order to embed one, two or three bits per the eight bit channel which results in three different hiding capacities. The second technique is an adaptive approach in transforming domain where a threshold value is calculated under a predefined location for embedding in order to identify the embedding strength of the embedding technique. The quality of the generated stego images was evaluated using both objective (PSNR) and Subjective (DSCQS) methods to ensure the reliability of our proposed methods. The experimental results revealed that PSNR is not a strong indicator of the perceived stego image quality, but not a bad interpreter also of the actual quality of stego images. Since the visual difference between the cover and the stego image must be absolutely imperceptible to the human visual system, it was logically convenient to ask human observers with different qualifications and experience in the field of image processing to evaluate the perceived quality of the cover and the stego image. Thus, the subjective responses were analysed using statistical measurements to describe the distribution of the scores given by the assessors. Thus, the proposed scheme presents an alternative approach to protect digital documents rather than the traditional techniques of digital signature and watermarking.

A garantia de bem-estar animal é essencial para assegurar resultados científicos confiáveis, e as técnicas de enriquecimento ambiental, utilizadas nessa busca, não podem ignorar as preferências e necessidades da espécie em questão, tais como o modo de utilização do espaço disponível. Nosso objetivo foi analisar como 35 gatos domésticos (12 machos e 23 fêmeas) utilizam seu espaço e as influências do enriquecimento ambiental nessa questão, visto que tal grupo contempla características de animais de companhia e também de biotério, sendo modelo em diversas pesquisas científicas. A utilização do espaço vertical foi quantificada a partir de filmagens das camas continuamente disponíveis em 4 níveis (0,60; 0,88; 1,16 e 1,46 m) e de refúgios (enriquecimento) em 3 diferentes alturas: 0, 0,5 e 1,0 m. Os resultados indicaram predileção pelas camas mais elevadas (1,46 m); entretanto, houve diferença significativa no tempo de utilização apenas para os refúgios a 0,5m, reforçando a importância de testar e confrontar as preferências dos animais em diferentes circunstâncias. Quanto ao uso do espaço horizontal, a disponibilização de refúgios alterou a distribuição dos animais na área de teste e aumentou comportamentos ativos e passivos. Testamos a escolha entre refúgios descobertos (100%) e com 50% de cobertura e também entre refúgios com aberturas laterais de 25% e 100%. Preferências não identificadas no primeiro teste (100% e 50% descobertas) tornaram-se aparentes quando as aberturas estavam nas laterais: os refúgios com 25% de abertura lateral foram utilizados por mais tempo. Tais resultados podem estar relacionados a ansiedade dos animais confinados, podendo esse teste ser uma potencial alternativa ao labirinto em cruz elevado para estudos de ansiedade com felinos. As diferenças observadas entre machos e fêmeas podem apontar influência diferenciada entre gêneros do confinamento no comportamento de animais castrados. Nossas conclusões ressaltam a necessidade do enriquecimento ambiental bem fundamentado na manutenção do bem-estar animal e sua interferência no uso do espaço. / The guarantee of animal welfare is essential to ensure reliable scientific results, and the techniques of environmental enrichment, used in this quest, shall not ignore the needs and preferences of the species in question, such as how to use the available space. Our objective was to analyze how 35 cats (12 males and 23 females), use their space and the influences of environmental enrichment on this issue, since this group includes characteristics of pets and also of laboratory animals, being a model in several scientific studies. The use of vertical space was quantified through the filming of the continuously available beds in four levels (0.60, 0.88, 1.16 and 1.46 m) and the refuges (enrichment) in three different heights: 0, 0.5 and 1.0 m. Our results show that there is a preference for the higher beds (1.46 m); however, significant differences in time use was observed only for refuges in 0.5 m, reinforcing the importance of testing and comparing the preferences of animals in different circumstances. Regarding the use of horizontal space, the availability of refuges changed the distribution of animals in the test area and increased active and passive behaviors. We tested the choice between uncovered shelters (100%) and ones with 50% coverage and also shelters with lateral openings between 25% and 100%. Preferences which were not identified in the first test (100% and 50% uncovered) became apparent when the openings were on the sides: refuges with 25% side opening were used for a longer period. This finding may be related to the anxiety of confined animals, and this test may be a potential alternative to the elevated plus maze for studies of anxiety in cats. The differences observed between males and females may indicate the influence between genders of confinement on the behavior of castrated animals. Our findings highlight the need for well founded environmental enrichment in the maintenance of animal welfare and its interference with the use of space.

Cette thèse aborde les problèmes liés à la protection de maillages d'objets 3D. Ces objets peuvent, par exemple, être créés à l'aide d'outil de CAD développés par la société STRATEGIES. Dans un cadre industriel, les créateurs de maillages 3D ont besoin de disposer d'outils leur permettant de vérifier l'intégrité des maillages, ou de vérifier des autorisations pour l'impression 3D par exemple. Dans ce contexte nous étudions l'insertion de données cachées dans des maillages 3D. Cette approche permet d'insérer de façon imperceptible et sécurisée de l'information dans un maillage. Il peut s'agir d'un identifiant, de méta-informations ou d'un contenu tiers, par exemple, pour transmettre de façon secrète une texture. L'insertion de données cachées permet de répondre à ces problèmes en jouant sur le compromis entre la capacité, l'imperceptibilité et la robustesse. Généralement, les méthodes d'insertion de données cachées se composent de deux phases, la synchronisation et l'insertion. La synchronisation consiste à trouver et ordonner les éléments disponibles pour l'insertion. L'un des principaux challenges est de proposer une méthode de synchronisation 3D efficace qui définit un ordre sur les composants des maillages. Dans nos travaux, nous proposons d'utiliser les sommets du maillage, plus précisément leur représentation géométrique dans l'espace comme composants de base pour la synchronisation et l'insertion. Nous présentons donc trois nouvelles méthodes de synchronisation de la géométrie des maillages basées sur la construction d'un chemin hamiltonien dans un nuage de sommets. Deux de ces méthodes permettent de manière conjointe de synchroniser les sommets et de cacher un message. Cela est possible grâce à deux nouvelles méthodes d'insertion haute capacité (de $3$ à $24$ bits par sommet) qui s'appuient sur la quantification des coordonnées. Dans ces travaux nous mettons également en évidence les contraintes propres à ce type de synchronisation. Nous discutons des différentes approches proposées dans plusieurs études expérimentales. Nos travaux sont évalués sur différents critères dont la capacité et l'imperceptibilité de la méthode d'insertion. Nous portons également notre attention aux aspects sécurité des méthodes. / This thesis addresses issues relating to the protection of 3D object meshes. For instance, these objects can be created using CAD tool developed by the company STRATEGIES. In an industrial context, 3D meshes creators need to have tools in order to verify meshes integrity, or check permission for 3D printing for example.In this context we study data hiding on 3D meshes. This approach allows us to insert information in a secure and imperceptible way in a mesh. This may be an identifier, a meta-information or a third-party content, for instance, in order to transmit secretly a texture. Data hiding can address these problems by adjusting the trade-off between capacity, imperceptibility and robustness. Generally, data hiding methods consist of two stages, the synchronization and the embedding. The synchronization stage consists of finding and ordering available components for insertion. One of the main challenges is to propose an effective synchronization method that defines an order on mesh components. In our work, we propose to use mesh vertices, specifically their geometric representation in space, as basic components for synchronization and embedding. We present three new synchronisation methods based on the construction of a Hamiltonian path in a vertex cloud. Two of these methods jointly perform the synchronization stage and the embedding stage. This is possible thanks to two new high-capacity embedding methods (from 3 to 24 bits per vertex) that rely on coordinates quantization. In this work we also highlight the constraints of this kind of synchronization. We analyze the different approaches proposed with several experimental studies. Our work is assessed on various criteria including the capacity and imperceptibility of the embedding method. We also pay attention to security aspects of the proposed methods.

<p>Då en människa får avslag på sin ansökan om uppehållstillstånd kan denne av olika skäl tvingas till att leva gömd. En vanlig orsak till detta är skräcken för vad som skulle kunna hända vid ett återvändande till hemlandet. Därmed väljer den avvisade en livssituation utan tillgång till olika samhälleliga rättigheter framför att vända tillbaka. Frånvaron av stödinsatser innebär ofta materiella, fysiska och psykiska konsekvenser. Hur individen hanterar dessa beror till viss del på orsaken till flykten, men också på det stöd andra människor kan ge. För att få en djupare förståelse för den gömdes situation, utformades syftet att undersöka vilka faktorer som påverkar hur en flykting som lever gömd kan hantera samt skapa mening och innehåll i sin livssituation. Detta ledde till följande frågeställningar: 1) Vilka faktorer beskrivs som inflytelserika för flyktingens förmåga att hantera sin livssituation som gömd? 2) På vilket sätt inverkar dessa faktorer på flyktingens möjlighet att hantera sin vardag? 3) Hur beskrivs flyktingens stöd från det sociala nätverket och på vilket sätt bidrar detta stöd till att skapa en meningsfull tillvaro? 4) Finns det gemensamma mönster eller skildringar i respondenternas berättelser som kan vara betydelsefulla för skapandet av mening? I denna studie har en kvalitativ metod använts, innefattande semistrukturerade intervjuer med tre flyktingar som levt gömda. Intervjufrågor formulerades utifrån tolkningsramens teoretiska perspektiv om meningsskapande med grund i logoterapi, KASAM och socialt stöd. Dessa perspektiv kopplades samman varpå socialt stöd blev en viktig komponent inom logoterapin och KASAM. I resultatet framgår att praktiska omständigheter, socialt nätverk samt livsåskådning är av vikt för att en gömd flykting ska kunna skapa mening och innehåll i sitt liv. Avgörande visade sig det sociala stödet vara, främst i form av nära mellanmänskliga relationer. Detta då dessa kontakter kan erbjuda socialt, emotionellt och självstärkande stöd. För att kunna skapa mening krävs också utrymme för existentiella frågor, egna känslor samt en huvudsaklig sysselsättning. Dessa måste tillskrivas ett värde för att KASAM ska kunna uppnås.</p> / <p>When denied the right to a permanent residence permit, a refugee can, for various reasons, be forced to lead a life in hiding. A common reason for this is the fear of what awaits in the country of origin. As a result, the “denied” chooses to proceed into a life without access to any societal rights rather than return home. The lack of organized support in such a situation contributes to difficult material, physical as well as psychological consequences. The manner each individual has of handling these are highly dependent upon their reasons for fleeing, as well as the support they receive. To achieve a broader understanding of a life in hiding, the factors that influence the manner the affected refugee can handle, as well as create meaning and content in his/her situation, have been investigated. Subsequently, the following questions were asked: 1) which factors are described as significant in regards to the refugee’s ability to handle a life in hiding? 2) In which ways do these factors affect the refugee’s ability to handle his/her everyday life? 3) How is the support of the social network described, and in which ways can this support help create a meaningful existence? 4) Are there any patterns to be found in the narratives of the informants that can contribute to a meaningful existence? In this study, a qualitative method was used comprising semi-structured interviews with three refugees having lead lives in hiding. Interview questions were developed using the study’s theoretical framework, consisting of logotherapy, KASAM and social support. As these perspectives were combined, social support proved to be an important component in both logotherapy and KASAM. The study concluded that practical circumstances, a social network as well as the “outlook on life” were essential to enable the creation of meaning in the hidden individual’s life. Close relationships were demonstrated as the most vital aspect, as they offer emotional, social as well as self-strengthening support. In addition to this, personal feelings, existential questioning and a primary occupation are needed to create meaning. These must be valued as important to achieve KASAM.</p>