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. / 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.

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.

The security of a steganography system is defined by our ability to detect it. It is of no surprise then that steganography and steganalysis both depend heavily on the accuracy and robustness of our detectors. This is especially true when real-world data is considered, due to its heterogeneity. The difficulty of such data manifests itself in a penalty that has periodically been reported to affect the performance of detectors built on binary classifiers; this is known as cover source mismatch. It remains unclear how the performance drop that is associated with cover source mismatch is mitigated or even measured. In this thesis we aim to show a robust methodology to empirically measure its effects on the detection accuracy of steganalysis classifiers. Some basic machine-learning based methods, which take their origin in domain adaptation, are proposed to counter it. Specifically, we test two hypotheses through an empirical investigation. First, that linear classifiers are more robust than non-linear classifiers to cover source mismatch in real-world data and, second, that linear classifiers are so robust that given sufficiently large mismatched training data they can equal the performance of any classifier trained on small matched data. With the help of theory we draw several nontrivial conclusions based on our results. The penalty from cover source mismatch may, in fact, be a combination of two types of error; estimation error and adaptation error. We show that relatedness between training and test data, as well as the choice of classifier, both have an impact on adaptation error, which, as we argue, ultimately defines a detector's robustness. This provides a novel framework for reasoning about what is required to improve the robustness of steganalysis detectors. Whilst our empirical results may be viewed as the first step towards this goal, we show that our approach provides clear advantages over earlier methods. To our knowledge this is the first study of this scale and structure.

The effects of goal interdependence on employees’ performance outcomes have been well documented in the literature. Yet, the relationship between goal interdependence and employees’ proactive behaviors remains largely unexplored. Integrating the theory of cooperation and competition with the employee proactivity literature, this study investigates how cooperative goal interdependence and competitive goal interdependence respectively influence employee knowledge sharing and knowledge hiding, and in turn shape their propensity to seek help from coworkers. It further examines reciprocity beliefs as an individual factor in affecting the indirect effect of goal interdependence on help seeking. Specifically, positive reciprocity belief is hypothesized to moderate the mediating role of knowledge sharing, whereas negative reciprocity belief is expected to moderate the mediating effect of knowledge hiding. In Study 1, a total of 127 interviews were conducted with full-time employees working in professional service firms across four cities including Hong Kong, Macau, China and Taiwan. Results of structural equation modeling supported the mediating role of knowledge sharing in the relationship between cooperative goal interdependence and employee help seeking. In Study 2, an experimental study was conducted with 150 full-time students at a university in Macau to replicate the findings in Study 1 and to test the moderation hypotheses. It yielded findings consistent with Study 1 and supportive of the moderating role of negative reciprocity belief in the mediated effect of goal interdependence on help seeking. Specifically, knowledge hiding mediates the relationship between competitive goal interdependence and help seeking, when an individual is high in negative reciprocity belief. Findings of the two studies provide both theoretical contributions to the literature and practical insights to organizations. Cooperative goal interdependence is a valuable method for managers to promote knowledge sharing, inhibit knowledge hiding, and encourage active help seeking among employees.

No description available.

No description available.

Esteganografia é uma técnica utilizada para ocultar uma informação secreta dentro de outro tipo de informação sem perda de qualidade da informação hospedeira e com o objetivo de extrair a informação posteriormente. Esteganografia reversível permite a exata restauração (sem perda) do sinal hospedeiro original após a extração da informação oculta. Várias ténicas reversíveis têm sido desenvolvidas, mas nenhuma delas parece ser apropriada para imagens binárias. Uma técnica de marca d\'água faz uso de técnicas esteganográficas para inserir informação em uma imagem hospedeira, com o intuito de fazer uma asserção sobre a imagem no futuro. Uma marca d\'água de autenticação (AWT) insere uma informação oculta na imagem com a intenção de detectar qualquer alteração acidental ou maliciosa na imagem. Uma AWT normalmente usa criptografia de chave secreta ou chave pública para computar a assinatura de autenticação da imagem, inserindo-a na própria imagem. JBIG2 é um padrão internacional para compressão de imagens binárias (com ou sem perda). Ele decompõe a imagem em várias regiões (texto, meio-tom e genérica) e codifica cada região usando o método mais apropriado. A criação de AWTs seguras para imagens binárias comprimidas é um importante problema prático. Porém, parece que nenhuma AWT para JBIG2 já foi proposta. Este trabalho propõe algumas técnicas esteganográficas para arquivos JBIG2. Então, estas técnicas são usadas para criar AWTs para imagens codificadas como JBIG2. As imagens marcadas são visualmente agradáveis, sem ruídos do tipo sal-e-pimenta. Este trabalho também propõe uma técnica esteganográfica reversível para imagens binárias. A técnica proposta seleciona um conjunto de pixels de baixa visibilidade e utiliza o algoritmo de Golomb para comprimir as previsões desses pixels. Então, a informação comprimida e a informação a ser oculta são inseridas na imagem. Imagens marcadas com a técnica proposta possuem excelente qualidade visual, pois apenas pixels de baixa visibilidade são modificados. Então, a técnica proposta é utilizada para autenticar imagens binárias e documentos de maneira reversível. / Data-hiding is a technique to hide secret information inside another group of information data, without loss of quality of the host information, and the means to extract the secret information afterwards. Reversible data-hiding enable the exact restoration (lossless) of the original host signal after extracting the embedded information. Several reversible data hiding techniques have been developed, but none of them seems to be appropriate for binary images. A watermarking technique makes use of data-hiding to insert some information into the host image, in order to make a posterior assertion about the image. An authentication watermarking technique (AWT) inserts hidden data into an image in order to detect any accidental or malicious alteration to the image. AWT normally makes use of secret- or publickey cryptographic ciphers to compute the authentication signature of the image, and inserts it into the image itself. JBIG2 is an international standard for compressing bilevel images in both lossy and lossless modes. JBIG2 decomposes the image into several regions (text, halftone and generic) and encodes each one using the most appropriate method. The creation of secure AWTs for compressed binary images is an important practical problem. However, it seems that no AWT for JBIG2 has ever been proposed. This work proposes some data-hiding techniques for JBIG2 files. Then, these techniques are used to design AWTs for JBIG2-encoded images. The resulting watermarked images are visually pleasant, without visible salt and pepper noise. This work also proposes a reversible data hiding technique for binary images. The proposed technique selects a set of low-visibility pixels and uses Golomb codes to compress the predictions of these pixels. Then, this compressed data and the net payload data are embedded into the image. Images watermarked by the proposed technique have excellent visual quality, because only low-visibility pixels are flipped. Then, the proposed data hiding is used to reversibly authenticate binary images and documents.

Esteganografia é uma técnica utilizada para ocultar uma informação secreta dentro de outro tipo de informação sem perda de qualidade da informação hospedeira e com o objetivo de extrair a informação posteriormente. Esteganografia reversível permite a exata restauração (sem perda) do sinal hospedeiro original após a extração da informação oculta. Várias ténicas reversíveis têm sido desenvolvidas, mas nenhuma delas parece ser apropriada para imagens binárias. Uma técnica de marca d\'água faz uso de técnicas esteganográficas para inserir informação em uma imagem hospedeira, com o intuito de fazer uma asserção sobre a imagem no futuro. Uma marca d\'água de autenticação (AWT) insere uma informação oculta na imagem com a intenção de detectar qualquer alteração acidental ou maliciosa na imagem. Uma AWT normalmente usa criptografia de chave secreta ou chave pública para computar a assinatura de autenticação da imagem, inserindo-a na própria imagem. JBIG2 é um padrão internacional para compressão de imagens binárias (com ou sem perda). Ele decompõe a imagem em várias regiões (texto, meio-tom e genérica) e codifica cada região usando o método mais apropriado. A criação de AWTs seguras para imagens binárias comprimidas é um importante problema prático. Porém, parece que nenhuma AWT para JBIG2 já foi proposta. Este trabalho propõe algumas técnicas esteganográficas para arquivos JBIG2. Então, estas técnicas são usadas para criar AWTs para imagens codificadas como JBIG2. As imagens marcadas são visualmente agradáveis, sem ruídos do tipo sal-e-pimenta. Este trabalho também propõe uma técnica esteganográfica reversível para imagens binárias. A técnica proposta seleciona um conjunto de pixels de baixa visibilidade e utiliza o algoritmo de Golomb para comprimir as previsões desses pixels. Então, a informação comprimida e a informação a ser oculta são inseridas na imagem. Imagens marcadas com a técnica proposta possuem excelente qualidade visual, pois apenas pixels de baixa visibilidade são modificados. Então, a técnica proposta é utilizada para autenticar imagens binárias e documentos de maneira reversível. / Data-hiding is a technique to hide secret information inside another group of information data, without loss of quality of the host information, and the means to extract the secret information afterwards. Reversible data-hiding enable the exact restoration (lossless) of the original host signal after extracting the embedded information. Several reversible data hiding techniques have been developed, but none of them seems to be appropriate for binary images. A watermarking technique makes use of data-hiding to insert some information into the host image, in order to make a posterior assertion about the image. An authentication watermarking technique (AWT) inserts hidden data into an image in order to detect any accidental or malicious alteration to the image. AWT normally makes use of secret- or publickey cryptographic ciphers to compute the authentication signature of the image, and inserts it into the image itself. JBIG2 is an international standard for compressing bilevel images in both lossy and lossless modes. JBIG2 decomposes the image into several regions (text, halftone and generic) and encodes each one using the most appropriate method. The creation of secure AWTs for compressed binary images is an important practical problem. However, it seems that no AWT for JBIG2 has ever been proposed. This work proposes some data-hiding techniques for JBIG2 files. Then, these techniques are used to design AWTs for JBIG2-encoded images. The resulting watermarked images are visually pleasant, without visible salt and pepper noise. This work also proposes a reversible data hiding technique for binary images. The proposed technique selects a set of low-visibility pixels and uses Golomb codes to compress the predictions of these pixels. Then, this compressed data and the net payload data are embedded into the image. Images watermarked by the proposed technique have excellent visual quality, because only low-visibility pixels are flipped. Then, the proposed data hiding is used to reversibly authenticate binary images and documents.

The thesis presents research on multiobjective optimization based on memetic computing and its applications in engineering. We have introduced a framework for adaptive multiobjective memetic optimization algorithms (AMMOA) with an information theoretic criterion for guiding the selection, clustering, and local refinements. A robust stopping criterion for AMMOA has also been introduced to solve non-linear and large-scale optimization problems. The framework has been implemented for different benchmark test problems with remarkable results. This thesis also presents two applications of these algorithms. First, an optimal image data hiding technique has been formulated as a multiobjective optimization problem with conflicting objectives. In particular, trade-off factors in designing an optimal image data hiding are investigated to maximize the quality of watermarked images and the robustness of watermark. With the fixed size of a logo watermark, there is a conflict between these two objectives, thus a multiobjective optimization problem is introduced. We propose to use a hybrid between general regression neural networks (GRNN) and the adaptive multiobjective memetic optimization algorithm (AMMOA) to solve this challenging problem. This novel image data hiding approach has been implemented for many different test natural images with remarkable robustness and transparency of the embedded logo watermark. We also introduce a perceptual measure based on the relative Rényi information spectrum to evaluate the quality of watermarked images. The second application is the problem of joint spectrum sensing and power control optimization for a multichannel, multiple-user cognitive radio network. We investigated trade-off factors in designing efficient spectrum sensing techniques to maximize the throughput and minimize the interference. To maximize the throughput of secondary users and minimize the interference to primary users, we propose a joint determination of the sensing and transmission parameters of the secondary users, such as sensing times, decision threshold vectors, and power allocation vectors. There is a conflict between these two objectives, thus a multiobjective optimization problem is used again in the form of AMMOA. This algorithm learns to find optimal spectrum sensing times, decision threshold vectors, and power allocation vectors to maximize the averaged opportunistic throughput and minimize the averaged interference to the cognitive radio network. / February 2016

Digital steganography is a technique for hiding data mostly into multimedia files (images, audio, video). With the development of information technology this technique has found its use in the field of copyright protection and secret data transfer, could be even applied in places where is limited possibility of using cryptography (e. g. by law). This thesis gives insight into digital steganography and contains an application using this technique.