Characterizing complex tissues requires precise identification of distinctive cell types, cell-specific signatures, and subpopulation proportions. Tissue heterogeneity, arising from multiple cell types, is a major confounding factor in studying individual subpopulations and repopulation dynamics. Tissue heterogeneity cannot be resolved directly by most global molecular and genomic profiling methods. While signal deconvolution has widespread applications in many real-world problems, there are significant limitations associated with existing methods, mainly unrealistic assumptions and heuristics, leading to inaccurate or incorrect results. In this study, we formulate the signal deconvolution task as a blind source separation problem, and develop novel unsupervised deconvolution methods within the Convex Analysis of Mixtures (CAM) framework, for characterizing multi-scale tissue heterogeneity. We also explanatorily test the application of Significant Intercellular Genomic Heterogeneity (SIGH) method. Unlike existing deconvolution methods, CAM can identify tissue-specific markers directly from mixed signals, a critical task, without relying on any prior knowledge. Fundamental to the success of our approach is a geometric exploitation of tissue-specific markers and signal non-negativity. Using a well-grounded mathematical framework, we have proved new theorems showing that the scatter simplex of mixed signals is a rotated and compressed version of the scatter simplex of pure signals and that the resident markers at the vertices of the scatter simplex are the tissue-specific markers. The algorithm works by geometrically locating the vertices of the scatter simplex of measured signals and their resident markers. The minimum description length (MDL) criterion is applied to determine the number of tissue populations in the sample. Based on CAM principle, we integrated nonnegative independent component analysis (nICA) and convex matrix factorization (CMF) methods, developed CAM-nICA/CMF algorithm, and applied them to multiple gene expression, methylation and protein datasets, achieving very promising results validated by the ground truth or gene enrichment analysis. We integrated CAM with compartment modeling (CM) and developed multi-tissue compartment modeling (MTCM) algorithm, tested on real DCE-MRI data derived from mouse models with consistent and plausible results. We also developed an open-source R-Java software package that implements various CAM based algorithms, including an R package approved by Bioconductor specifically for tumor-stroma deconvolution. While intercellular heterogeneity is often manifested by multiple clones with distinct sequences, systematic efforts to characterize intercellular genomic heterogeneity must effectively distinguish significant genuine clonal sequences from probabilistic fake derivatives. Based on the preliminary studies originally targeting immune T-cells, we tested and applied the SIGH algorithm to characterize intercellular heterogeneity directly from mixed sequencing reads. SIGH works by exploiting the statistical differences in both the sequencing error rates at different nucleobases and the read counts of fake sequences in relation to genuine clones of variable abundance. / Ph. D.

This thesis describes the design and implementation of an innovative drawing interpretation tool for the sight-impaired. The move towards Graphical User Interfaces in today's computer era presents many challenges to those with impaired vision. Although there are many tools to aid this group in reading and writing text-based electronic documents, few software packages are available to help the sight-impaired interpret electronic images. This new tool, known as ImagePilot 2.0, processes electronic image files that contain line drawings and produces audio feedback to guide the user through the drawing. ImagePilot 2.0 receives input through a pointing device, thereby providing the user with a means of examining a drawing interactively, and serving as an aid for recognizing the outlines of familiar shapes and objects. In this study, a "line drawing" is a simple image that contains line segments and curves, without any shading or colors. It can be represented as a 2-dimensional array of picture elements (pixels), in which each pixel is either black or white. The drawing is represented by a pattern of black (foreground) pixels against a white background. Typically, groups of connected foreground pixels represent segments or curves that are associated with a single object. ImagePilot 2.0 makes it possible for a sight-impaired user to interrogate such an image. Line drawings can be stored in many different electronic formats. ImagePilot 2.0 supports valid Graphic Interchange Format (GIF) files. If the foreground image regions in the file are wider than one pixel in width, a Zhang-Suen thinning algorithm is applied to thin the drawing. The tool identifies the separate regions in the drawing and decides on the best starting point for each region. Once a starting point is chosen, the drawing is processed using a modified chain-coding algorithm. The audio feedback consists of two types of audio cues, verbal and tone, along with stereo playback. Verbal feedback guides the user with a set of verbal cues played through the speakers. The tone feedback uses three tones representing above, level, and below the horizontal. The left and right speakers provide left and right directional information at each level. Speed is a critical factor in image analysis and interpretation applications. While the tool is receiving and processing input, it must also respond to the user within an acceptable amount of time. ImagePilot 2.0 uses multi-threading and multi-tasking techniques to achieve higher performance speeds. After design and implementation, two groups of people tested the tool. The tool demonstrated the ability to help the user find and trace the segments in the test drawings with high efficiency and acceptable response time. This tool is written in pure Java, and complies with Sun's Java API specification 1.1.7 released in October 1998. The tool functions on systems with multimedia capabilities that have a Java Virtual Machine (JVM) and Java Media Framework (JMF) installed. / Master of Science

The resonance of a knock on a door uncovers its density. The smell of a wall describes its materiality. The texture of a floor may invite us to sit or lay down. The smoothness of a handrail comforts our ascent. Human skin is a powerful material that enables us to perceive and understand our surroundings. Skin is highly expressive; based on its color, texture, wear and plasticity we can read it, gathering information concerning culture, ethnic background, age, abuse, health and the tasks it performs on specific body parts. Skin itself reads as it is readable. Our skin can gather data through tactile perception and read our spatial surroundings. Architecture is an expressive act and the only discipline that stimulates all of our senses. An architect designs spaces that foresee and celebrate the bodily interaction of the inhabitant. The architecture of the 21st century seems to be geared toward a more optic experience, an influence of the digital world and its widespread effect. The architectural body of modern construction is made up of skins that convey no intentions of interaction between human skin, delivering a concoction of low quality materials that time and again are layered the same way and only aim to be cost efficient. The result is a bland, empty and "flat" experience. In a culture dominated by visual stimulation, can the design of architectural skins aid in the reading and understanding through touch of an architectural body's spatial sequence? / Master of Architecture

Thesis (Ed.D.)--Boston University / Research suggests that web-based education increases opportunities for underserved populations to be integrated into educational activities (Schmetzke, 2001; Burgstahler, 2002; Opitz, Savenye, & Rowland, 2003). This may be true for students with disabilities because they have more flexibility to participate in formal education. However, Moisey (2004) found that people with disabilities had lower rates of enrollment and educational achievement than people without disabilities. These findings raise the question of whether or not web-based = education helps increase students with disabilities' access to learning opportunities and improve their learning outcome. This study investigated the degree of difficulty blind persons had in accessing and using web-based educational resources provided by Thailand Cyber University (TCU). Based on a mixed methods design, the data were collected in two phases. Quantitative data were collected first, in order to identify accessibility problems and conformance levels reported by automated web accessibility evaluation tools. Qualitative data was collected from interviews with blind participants in the second phase to expand the understanding of the accessibility problems and usability issues that were not discovered in the quantitative phase by the automated web accessibility evaluation tools. The findings indicate that all of the 13 selected web pages failed to meet a minimum requirement of WCAG 2.0. This means those selected web pages would be inaccessible for the blind. However, the findings indicate blind participants rated only one of the 13 pages as inaccessible. Moreover, their ratings of difficulty on "usability" were higher than their ratings of difficulty on "accessibility" on the same web page. On six out of 22 tasks, blind and sighted user groups agreed on the ratings. Nevertheless, the time that it took to complete each task varied greatly between the two user groups. / 2999-01-01

Anxiety levels of partially sighted were compared with totally blind people. Using the Anxiety Scale for the Blind, the primary hypothesis tested was that the partially sighted would manifest more anxiety than would the totally blind. The study was designed to ascertain whether the primary hypothesis would hold within the structure of this study, and to obtain information useful in future anxiety studies of the visually handicapped. A residential center for the blind furnished subjects, facilities, and biographical data. The primary hypothesis lacked statistical significance at the .05 level as did comparisons of anxiety levels by age, sex, economic need, and age at onset. The use of a different instrument may be indicated for future studies.

No description available.

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 203-204. / by Frank C. Conati. / M.S.

Neste trabalho, investigam-se técnicas autodidatas baseadas em estatísticas de ordem superior, aplicadas à equalização de canais de comunicação. Inicialmente, obtém-se um intervalo do passo de adaptação que assegura a convergência do algoritmo do Módulo Constante com o gradiente exato. Algoritmos como o CMA (Constant Modulus Algorithm) e o SWA (Shalvi-Weinstein Algorithm) são revisitados e suas capacidades de tracking analisadas, utilizando-se uma relação de conservação de energia. Além disso, é proposto um algoritmo autodidata denominado AC-CMA (Accelerated Constant Modulus Algorithm) que utiliza a segunda derivada (“aceleração") da estimativa dos coeficientes. Esse algoritmo pode apresentar um compromisso mais favorável entre complexidade computacional e velocidade de convergência que o CMA e o SWA. Esses resultados são estendidos para o caso multiusuário. Através de simulações, os algoritmos são comparados e as análises de convergência e tracking validadas. Considerando o DFE (Decision Feedback Equalizer) no caso monousuário com o critério do módulo constante, é proposto um algoritmo concorrente que evita soluções degeneradas e apresenta um desempenho melhor do que os existentes na literatura. Com o intuito de evitar propagação de erros, é proposta uma estrutura híbrida que utiliza uma rede neural recorrente na malha de realimentação. Resultados de simulações indicam que seu uso pode ser vantajoso para canais lineares e não-lineares. / The equalization of communication channels is addressed by using blind techniques based on higher order statistics. A step-size interval is obtained to ensure the convergence of Steepest-Descent Constant Modulus Algorithm. The Shalvi-Weinstein Algorithm (SWA) and Constant Modulus Algorithm (CMA) are revisited and their tracking capabilities are analyzed by using an energy conservation relation. Moreover, a novel blind algorithm named Accelerated Constant Modulus Algorithm (AC-CMA) is proposed. It adjusts the second derivative (“acceleration") of the coefficient estimates and presents a more favorable compromise between computational complexity and convergence rate than CMA or SWA. These results are extended to the MIMO (Multiple-Input Multiple-Output) case. By means of simulations, the algorithms are compared and the convergence and tracking analysis are validated. The Decision Feedback Equalizer (DFE) is considered in the SISO (Single-Input Single-Output) case with the Constant Modulus criterion and a concurrent algorithm is proposed. It avoids degenerated solutions and shows better behavior than the others presented in the literature. In order to avoid error propagation, a hybrid DFE is also proposed. It includes a recurrent neural network in the feedback filter and may be advantageously used to equalize linear and nonlinear channels.

Neste trabalho, investigam-se técnicas autodidatas baseadas em estatísticas de ordem superior, aplicadas à equalização de canais de comunicação. Inicialmente, obtém-se um intervalo do passo de adaptação que assegura a convergência do algoritmo do Módulo Constante com o gradiente exato. Algoritmos como o CMA (Constant Modulus Algorithm) e o SWA (Shalvi-Weinstein Algorithm) são revisitados e suas capacidades de tracking analisadas, utilizando-se uma relação de conservação de energia. Além disso, é proposto um algoritmo autodidata denominado AC-CMA (Accelerated Constant Modulus Algorithm) que utiliza a segunda derivada (“aceleração”) da estimativa dos coeficientes. Esse algoritmo pode apresentar um compromisso mais favorável entre complexidade computacional e velocidade de convergência que o CMA e o SWA. Esses resultados são estendidos para o caso multiusuário. Através de simulações, os algoritmos são comparados e as análises de convergência e tracking validadas. Considerando o DFE (Decision Feedback Equalizer) no caso monousuário com o critério do módulo constante, é proposto um algoritmo concorrente que evita soluções degeneradas e apresenta um desempenho melhor do que os existentes na literatura. Com o intuito de evitar propagação de erros, é proposta uma estrutura híbrida que utiliza uma rede neural recorrente na malha de realimentação. Resultados de simulações indicam que seu uso pode ser vantajoso para canais lineares e não-lineares. / The equalization of communication channels is addressed by using blind techniques based on higher order statistics. A step-size interval is obtained to ensure the convergence of Steepest-Descent Constant Modulus Algorithm. The Shalvi-Weinstein Algorithm (SWA) and Constant Modulus Algorithm (CMA) are revisited and their tracking capabilities are analyzed by using an energy conservation relation. Moreover, a novel blind algorithm named Accelerated Constant Modulus Algorithm (AC-CMA) is proposed. It adjusts the second derivative (“acceleration”) of the coefficient estimates and presents a more favorable compromise between computational complexity and convergence rate than CMA or SWA. These results are extended to the MIMO (Multiple-Input Multiple-Output) case. By means of simulations, the algorithms are compared and the convergence and tracking analysis are validated. The Decision Feedback Equalizer (DFE) is considered in the SISO (Single-Input Single-Output) case with the Constant Modulus criterion and a concurrent algorithm is proposed. It avoids degenerated solutions and shows better behavior than the others presented in the literature. In order to avoid error propagation, a hybrid DFE is also proposed. It includes a recurrent neural network in the feedback filter and may be advantageously used to equalize linear and nonlinear channels.

In the 1960s, a group of blind activists, led by a charismatic young blind leader, attempted to take control of a residential school for the blind in Vinton, Iowa. The group of activists belonged to the Iowa Association of the Blind, the state affiliate of the National Federation of the Blind (NFB); the leader was Kenneth Jernigan, the first blind director of the Iowa Commission for the Blind; and the school was the Iowa Braille and Sight-Saving School (IBSSS), a venerable institution founded in the mid nineteenth century, and a cornerstone and iconic institution in the small northeast Iowa farming community of Vinton. Through the decade of the 1960s, Iowa was the central front of a civil rights movement, led by blind people determined to implement a new philosophy of blindness against what they perceived to be the entrenched power of sighted rehabilitation and education professionals. For ten years the Iowa Commission for the Blind and the Braille School were at odds with each other as both institutions fought for the hearts and minds of blind adults and children. Constant friction marked relations between the director of the Commission and the superintendent of the school, the former a blind activist administrator, the latter a sighted professional educator of the blind. The former, along with the organized blind whom he led, were not willing to let professionals speak for them, but insisted on speaking for themselves. The blind came to see the Braille School as the biggest obstacle to achieving their goals of advancing the civil rights of the blind in Iowa and beyond. The solution was to seek to take control of the school from the University Board of Regents and put it under the authority of the Commission for the Blind. The effort nearly succeeded, but the cost grew too high, and the battle for the Braille School would mark the beginning of the end of Jernigan's time in Iowa and set back the blind movement in ways not recognized until much later. Blind citizens in the 1940s and 50s faced widespread and entrenched discrimination. The ability to work, to own one's home, to travel independently on public transportation, to serve on trial juries, to vote, to adopt children, to raise families, were rights that no law guaranteed. The Architectual Barriers Act, Rehabilitation Act, Education of All Handicapped Children Act, and the Americans with Disabilities Act were all still decades in the future. It was the hope of Kenneth Jernigan and the blind whom he led to use the vocational rehabilitation program for the blind in Iowa to secure some of the rights the blind lacked, and to advance a new vision of what it meant to be blind.