The gallery has always sparked an expectant feeling of forgetfulness in me, whether I am an unsuspecting viewer or conceiving of an installation for a particular space. More specifically, entering an art gallery evokes a feeling of being in between the safe, assured and comforting feeling of knowing, and the completely lost and vague feeling of having my mind turn blank. The moment of entry -- if I could slow it down and clearly perceive my heightened expectation -- is like going into a room to get something but forgetting what Im looking for. I liken the experience to that of going into the basement for something -- not quite remembering what -- and opening a box. It might be the height of summer or above ground there might be three feet of snow. The basement is cool, like always; it is dark, a little damp, in a state of disarray or rigid organization. Within the stacks of boxes there are the possibilities of finding Christmas lights and water wings alike. Until a box is opened or its label read, the basement is neutral, quiet and waiting.<p>Scrappy the Bandit and the Outlaw Wolf has come to encompass this type of experience: the ambiguity of being both the moment before something happens, and the tucked-away-until-next-year Long Goodbye of an events neatened and tissue-wrapped aftermath. And the heart of this exhibition offers a number of parallel narratives; these are illustrated by coils of pennants seemingly stored away, a perch in which to sit and wait, a shelter from which to make forays, and an oversize toy wolf that watches over the space.

The gallery has always sparked an expectant feeling of forgetfulness in me, whether I am an unsuspecting viewer or conceiving of an installation for a particular space. More specifically, entering an art gallery evokes a feeling of being in between the safe, assured and comforting feeling of knowing, and the completely lost and vague feeling of having my mind turn blank. The moment of entry -- if I could slow it down and clearly perceive my heightened expectation -- is like going into a room to get something but forgetting what Im looking for. I liken the experience to that of going into the basement for something -- not quite remembering what -- and opening a box. It might be the height of summer or above ground there might be three feet of snow. The basement is cool, like always; it is dark, a little damp, in a state of disarray or rigid organization. Within the stacks of boxes there are the possibilities of finding Christmas lights and water wings alike. Until a box is opened or its label read, the basement is neutral, quiet and waiting.<p>Scrappy the Bandit and the Outlaw Wolf has come to encompass this type of experience: the ambiguity of being both the moment before something happens, and the tucked-away-until-next-year Long Goodbye of an events neatened and tissue-wrapped aftermath. And the heart of this exhibition offers a number of parallel narratives; these are illustrated by coils of pennants seemingly stored away, a perch in which to sit and wait, a shelter from which to make forays, and an oversize toy wolf that watches over the space.

The bedload transport of mixed size sediment is an important process in river engineering. Bedload transport controls channel stability and has a significant bearing on the hydraulic roughness of the channel. The prediction of bedload transport traditionally relies upon defining some critical value of fluid force above which particles of a particular diameter are assumed to be put into transport. The suggestion here is that the transport of bed material is size dependent with large grains being more difficult to remove from the bed surface than small grains and that all grains of the same size start to move under identical conditions. While it is relatively straightforward to assess the forces required to engender transport in a bed of uniform size grains, it is not so simple where there are a number of different grain sizes present. Multitudinous experimental studies have revealed that where there are a number of grain sizes present, large grains tend to become mobilised under lower fluid forces and small grains mobilised under higher fluid forces than those required for beds of uniform material. These results led to the development of so-called hiding functions which are used to model the variation of particle mobility with its relative size within the mixture. These functions derive their name from the tendency of large grains to shelter smaller grains from the action of the flow. Determining the relative mobility of each fraction in a mixture under given hydraulic conditions is the key to predicting how the composition of the bed load will relate to that of the bed surface material. Experiments were carried out in a rectangular, glass sided channel, in a sediment recirculation mode, under varying hydraulic conditions with a set of six different sediment mixtures. Laser Doppler Anemometry (LDA) was used to attain instantaneous velocity measurements at a number of locations in the flow. A Laser Displacement Meter was used to measure the detailed topography of small sections of the bed surface. Novel analysis techniques facilitated the determination of the grain size distribution of the bed surface by a grid-by-number method. The minimum force required to entrain each grain could also be estimated by a grain pivoting analysis. This information represents the resistance of the bed grains to erosion by flowing water. With the critical conditions for the bed grains known, it is possible to estimate the proportion of each fraction entrained from the bed surface under given hydraulic conditions. To estimate the bedload composition it is first necessary to scale by the proportion each size comprises on the bed surface and then, by a function of grain diameter to account for size dependency of travel velocity. For mean hydraulic conditions the proportion of the bed mobilised can be simply determined by inspection of a cumulative distribution of critical conditions. In reality, although it may be possible to entrain some grains at the mean velocity/shear stress, the majority of transport may be anticipated to occur during high magnitude events. Turbulence may be incorporated by adopting a probabilistic approach to the prediction of grain entrainment. By considering the joint probability distribution of bed shear stress and critical shear stress, one may attain the probability of grain entrainment. Comparison of the probability of erosion of each fraction facilitates a prediction of the bedload composition. Results show that the probabilistic approach provides a significant improvement over deterministic methods for the prediction of bedload composition.

A digital watermark is a message robustly hidden within another digitized signal such as an image, a piece of music, a video, etc. . The principal applications of this technology are copyright protection and document fingerprinting. The robustness of watermarking algorithms against common geometrical deformations has drawn the attention of many researchers in the last ten years. Such distortions can result from usual processing of the media and/or malicious manipulations. As an example, a major concern for digital cinema industry is the illicit copy of movies with video cameras taking place in movie theaters. In this scenario, severe geometric distortions can jeopardize the retrieval of the watermark message from the illicit copies. The limitations and weaknesses of the previously proposed solutions to fight these distortions are presented. We developed a generalized construction method for periodic pseudo-random patterns. Based on these patterns, we designed a spread spectrum watermarking scheme with enhanced security properties. We investigated the detection probability and the interaction between exhaustive search and informed coding strategies. Finally, a scheme for the detection of a periodic structure and for the inversion of affine distortions was presented. We showed that the choice of the periodic repetition size involves a trade-off between robustness and secrecy. Thereafter, we studied the security flaw caused by the lack of secrecy in pilot-registration approaches. We proposed an innovative hiding scheme to remedy this issue. Our solution involves the extraction of robust local references from the content of the cover signal. Using this content normalized interpretation, we showed how one can design robust secret binary mask and modulate pilot signals in watermarking schemes. The efficiency of the approach is demonstrated on pilots derived from periodic structures. We also addressed the assessment of the degradation introduced by a geometrical distortion. We assume that a global rigid transform does not impair the perceptual value of an image and we propose a new criterion based on a local analysis of the geometrical deformations.

With the rapid development and popularity of information technology, criminals and mischievous computer users are given avenues to commit crimes and malicious activities. One of the commonly used tactics, called steganography, is to hide information under a cover media so that except participants, no one else knows the existence of such information. Many techniques have been proposed for hiding data in images, videos and audios, but there is not much research devoted to data hiding in the popular MS Office documents which have recently adopted Office Open XML (OOXML) format. In this research, we first focus on identifying several data hiding techniques for OOXML documents. Then, we design and develop a fast detection algorithm based on the unique internal structure of OOXML documents, which contains multiple XML files, by using multi-XML query technique. Experimental results show the proposed detection algorithm outperforms the traditional one in terms of detection speed and completeness, where performance is the key to success of detecting hidden data in OOXML documents due to the fact that millions of documents are generated and transferred over the internet every day. / UOIT

Un codi C rep el nom de Z2Z4-additiu si les seves coordenades es poden dividir en dos subconjunts X i Y , de tal manera que el codi punctured de C, obtingut en eliminar les coordenades que no es troben a X –o, respectivament, a Y – és un codi binari lineal – respectivament, un codi quaternari lineal–. La imatge del mapa de Gray de C és un codi binari i, sovint, no lineal, que s’anomena Z2Z4-lineal. Aquesta tesi presenta noves famílies de codis Z2Z4-additius, amb la particularitat que les seves imatges de Gray són codis Z2Z4-lineals que tenen els mateixos paràmetres i propietats que la coneguda família de codis de Reed-Muller binaris i lineals. També, tot considerant la classe de codis perfectes Z2Z4-lineals, els quals se sap que són completament regulars, es fan servir les construccions d’extensió, puncture, shorten i lifting, i s’estudia si els codis obtinguts són uniformement empaquetats o completament regulars. A més de proporcionar fiabilitat en els canals de comunicació, la teoria de codis s’ha aplicat recentment a l’esteganografia, és a dir, a la ciència d’ocultar informació confidencial dins d’altres missatges, aparentment inofensius –l’objecte recobridor–, de manera que terceres parts no puguin detectar l’esmentada informació. Aquest procés s’ha plantejat a la literatura modificant el bit menys significatiu dels símbols de l’objecte recobridor per transmetre el missatge secret (esteganografia binària), o bé modificant els dos bits menys significatius ( 1-esteganografia). Respecte a la 1-esteganografia, s’exposen dos nous mètodes d’embedding basats en codis perfectes Z2Z4-lineals, que assoleixen una taxa d’embedding més alta que amb altres mètodes ja coneguts, per una distorsió donada; mentre que es presenta un altre mètode, basat en el producte de dos o més codis de Hamming q-aris, conforme a l’esteganografia binària. / Un código C recibe el nombre de Z2Z4-aditivo si sus coordenadas se pueden dividir en dos subconjuntos X e Y , tales que el código punctured de C, obtenido a partir de eliminar las coordenadas que no están en X –o, respectivamente, en Y – es un código binario lineal –respectivamente, un código cuaternario lineal–. La imagen del mapa de Gray de C es un código Z2Z4-lineal, que es un código binario y, a menudo, no lineal. En esta tesis se presentan nuevas familias de códigos Z2Z4-aditivos, con la particularidad de que sus imágenes a través del mapa de Gray son códigos Z2Z4-lineales con los mismos parámetros y propiedades que la conocida familia de códigos de Reed-Muller binarios y lineales. Considerando la clase de códigos perfectos Z2Z4-lineales, los cuales se sabe que son completamente regulares, se han utilizado las construcciones de extensión, puncture, shorten y lifting, y estudiado si los códigos obtenidos en cada caso eran uniformemente empaquetados o completamente regulares. Además de proporcionar fiabilidad en los canales de comunicación, la teoria de códigos se ha aplicado recientemente a la esteganografía, es decir, a la ciencia de ocultar información confidencial en otros mensajes, aparentemente inofensivos –el objeto recubridor– de tal manera que dicha información no pueda ser detectada por terceros. Este proceso se ha planteado en la literatura modificando el bit menos significativo de los símbolos del objeto recubridor (esteganografía binaria), o bien modificando los dos bits menos significativos ( 1-esteganografía). Con respecto a la 1-esteganografía, se exponen dos nuevos métodos de embedding basados en códigos perfectos Z2Z4-lineales, que alcanzan una tasa de embedding superior a la de otros métodos anteriores, para una distorsión dada; mientras que se presenta otro método, basado en el producto de dos o más códigos de Hamming q-arios, conforme a la esteganografía binaria. / A code C is said to be Z2Z4-additive if its coordinates can be partitioned into two subsets X and Y , in such a way that the punctured code of C obtained by removing the coordinates outside X –or, respectively, Y – is a binary linear code –respectively, a quaternary linear code–. The Gray map image of C is a binary and often nonlinear code called Z2Z4-linear code. In this dissertation, new families of Z2Z4-additive codes are presented, with the particularity that their Gray map images are Z2Z4-linear codes having the same parameters and properties as the well-known family of binary linear Reed-Muller codes. Considering the class of perfect Z2Z4-linear codes, which are known to be completely regular, we have used the extension, puncture, shorten and lifting constructions, and studied the uniformly packed condition and completely regularity of the obtained codes. Besides providing reliability in communication channels, coding theory has been recently applied to steganography, i.e., the science of hiding sensitive information within an innocuouslooking message –the cover object– in such a way that third parties cannot detect that information. This hiding process has been addressed in the literature either by distorting the least significant bit of symbols in the cover object to transmit the secret message (binary steganography), or by distorting the two least significant bits ( 1-steganography). With respect to 1-steganography, two new embedding methods based on perfect Z2Z4- linear codes are introduced, achieving a higher embedding rate for a given distortion than previous methods; while another method, based on the product of more than two perfect q-ary Hamming codes, is presented conforming to binary steganography.

The first impression of a person or an object relies hugely on the appearance. When it comes to the judgment of an object, whether it is attractive or not, the appearance becomes crucial although many audiences, especially in the field of art, are aware of the fact that looks can be deceiving. An object that is fabricated well on the surface can disappoint the audience once the outer layer is breached; but on the other hand, something that appears to be boring at first glance can surprise you with its hidden real quality. I became fascinated with the latter and decided to explore the relationship between the exterior and the interior of an object; what is hidden and what is not. / GDI Master / Storytelling 2009

We present a novel data hiding method for compressed images. The method is designed to minimize the quality loss associated with data embedding into a JPEG image. The described technique uses the objective criterion such as the mean square error and the human visual system based criterion such as the Just Noticable Distortion metric for distortion minimization. The hiding method is designed under the restrictions of the JPEG compression standard to develop new image applications without any modifications or additions to the existing standard. An application example is presented in the thesis. The performance of the technique is examined at different image sizes and resolutions. The cost of hiding in terms of file length extension is examined. Some subjective experiments to determine the zero-perceived distortion hiding capacity are made. An application illustrating the usage of the technique is given. The described application embeds check-bits into JPEG images to facilitate the verification of the sender identity and the authenticity of the transmitted image. In this thesis, we give a list of requirements on the data hiding methods to implement standard compliant applications; design a provably good hiding method operating under these requirements; determine the critical performance points of the method and propose an application based on the method. We have performed some additional research to determine how our system works with high resolution images and existing other well-known algorithms for information hiding. The experiments on high-resolution images have shown that there exists a large embedding capacity for the high resolution images in spite of a loss of embedding density. The performance comparison experiments have shown that the spread spectrum technique offers a competitive but less efficient distortion performance.

Digital multimedia can be distributed via the internet efficiently with superior compression technologies. The chance of distributing digital intellectual properties, such as image, music, films, and software, being large-scale unauthorized copied and distributed are much increasing one possible and practical solution for the copyright protection is information hiding technology. Information hiding technology embeds a special data into multimedia data for copyright protection. However, the embedded data may be damaged by malicious attacks or common signal processing. In this thesis, an information hiding technique based on Fractal Orthonormal Basis is proposed. First, the original image is divided into NxN Range blocks, each range block is substituted by several Domain blocks (Fractal Orthonormal Basis), then the watermark information is embedded into the coefficients of the fractal orthonormal basis. Besides, our technique will be compare with the other two watermarking algorithm (using DCT and DWT). After the attacks of cropping, down-scaling, median filter, smoothing, noise, JPEG, SPIHT and EZW compression, the Fractal Orthonormal Basis watermarking technique shows better result of capacity, transparency and robustness. In addition, we only store parts of compression fractal codes and the permutation seed, and these can be the secret key for the security.

Around the time of the mass liquidations of ghettos across occupied-Poland in 1942, thousands of Polish Jews fled to the homes of former gentile neighbours, friends, colleagues, as well as strangers, in search of a precious and necessary resource: shelter. Once these liquidations were deemed complete and the majority of Polish Jews had been transported to their deaths at the extermination camps, remaining alive was itself a crime for Polish Jews. One common survival strategy was to hide in the homes of Polish gentiles, as other options, such as hiding in the open, necessitated further preparation; false documents, fluency in Polish, and connections in the gentile community, for instance. Drawing upon diaries, postwar testimonies, and oral interviews with Jews who experienced part of the occupation in hiding with Polish gentiles, this thesis highlights the multifaceted nature of relations between Jews and Poles in hiding, and argues that the behaviour of Polish aid-providers during the Holocaust in Poland unsettles distinctions between perpetrators, rescuers, and bystanders. Significantly, such categories have been rigidly maintained in much of the existing literature on Polish aid-providers. The individual chapters are devoted to the prevalence of payment for shelter, particularly in non-currency means such as property exchanges and services, and coercive, nonconsensual sexual relations in hiding. The final chapter focuses upon the region of Sokołów County and illustrates the constitutive and contextual differences between short and long-term shelter, the denunciation and murder of Jews in hiding by their Polish helpers, and the “unrighteous” actions of those declared Righteous Among the Nations. Each chapter traces the diversity of threats faced by Jews in hiding. To date, scholars have emphasized the great threat posed by the Germans gendarmes and the Polish “blue” police to Jews in hiding, and neglected the internal threats. The testimonies discussed in this thesis expose the multiple ways in which gentile aid-providers could endanger Jews in hiding.