1,598 research outputs found
Hierarchical DSSC structures based on single walled TiO2 nanotube arrays reach back-side illumination solar light conversion efficiency of 8%
In the present work we introduce a path to the controlled construction of
DSSCs based on hierarchically structured single walled, self-organized TiO2
layers. In a first step we describe a simple approach to selectively remove the
inner detrimental shell of anodic TiO2 nanotubes (NTs). This then allows
controlled well-defined layer-by-layer decoration of these TiO2-NT walls with
TiO2 nanoparticles (this in contrast to conventional TiO2 nanotubes). We show
that such defined multiple layered decoration can be optimized to build dye
sensitized solar cells that (under back-side illumination conditions) can yield
solar light conversion efficiencies in the range of 8 %. The beneficial effects
observed can be ascribed to a combination of three factors : 1) improved
electronic properties of the single walled tubes themselves, 2) a further
improvement of the electronic properties by the defined TiCl4 treatment, and 3)
a higher specific dye loading that becomes possible for the layer-by-layer
decorated single walled tubes.Comment: arXiv admin note: text overlap with arXiv:1610.0643
StairNet: Top-Down Semantic Aggregation for Accurate One Shot Detection
One-stage object detectors such as SSD or YOLO already have shown promising
accuracy with small memory footprint and fast speed. However, it is widely
recognized that one-stage detectors have difficulty in detecting small objects
while they are competitive with two-stage methods on large objects. In this
paper, we investigate how to alleviate this problem starting from the SSD
framework. Due to their pyramidal design, the lower layer that is responsible
for small objects lacks strong semantics(e.g contextual information). We
address this problem by introducing a feature combining module that spreads out
the strong semantics in a top-down manner. Our final model StairNet detector
unifies the multi-scale representations and semantic distribution effectively.
Experiments on PASCAL VOC 2007 and PASCAL VOC 2012 datasets demonstrate that
StairNet significantly improves the weakness of SSD and outperforms the other
state-of-the-art one-stage detectors
Windows into Sensory Integration and Rates in Language Processing: Insights from Signed and Spoken Languages
This dissertation explores the hypothesis that language processing proceeds in "windows" that correspond to representational units, where sensory signals are integrated according to time-scales that correspond to the rate of the input. To investigate universal mechanisms, a comparison of signed and spoken languages is necessary. Underlying the seemingly effortless process of language comprehension is the perceiver's knowledge about the rate at which linguistic form and meaning unfold in time and the ability to adapt to variations in the input.
The vast body of work in this area has focused on speech perception, where the goal is to determine how linguistic information is recovered from acoustic signals. Testing some of these theories in the visual processing of American Sign Language (ASL) provides a unique opportunity to better understand how sign languages are processed and which aspects of speech perception models are in fact about language perception across modalities.
The first part of the dissertation presents three psychophysical experiments investigating temporal integration windows in sign language perception by testing the intelligibility of locally time-reversed sentences. The findings demonstrate the contribution of modality for the time-scales of these windows, where signing is successively integrated over longer durations (~ 250-300 ms) than in speech (~ 50-60 ms), while also pointing to modality-independent mechanisms, where integration occurs in durations that correspond to the size of linguistic units. The second part of the dissertation focuses on production rates in sentences taken from natural conversations of English, Korean, and ASL. Data from word, sign, morpheme, and syllable rates suggest that while the rate of words and signs can vary from language to language, the relationship between the rate of syllables and morphemes is relatively consistent among these typologically diverse languages. The results from rates in ASL also complement the findings in perception experiments by confirming that time-scales at which phonological units fluctuate in production match the temporal integration windows in perception.
These results are consistent with the hypothesis that there are modality-independent time pressures for language processing, and discussions provide a synthesis of converging findings from other domains of research and propose ideas for future investigations
Accelerated Life Testing to Predict Service Life and Reliability for an Appliance Door Hinge
Appliance manufacturers have traditionally performed physical testing using prototypes to assess reliability and service integrity of new product designs. However, for white goods where service lives are measured in years or decades, the use of endurance testing to analyze long time reliability is uneconomical. As accelerated life testing (ALT) is more efficient and less costly than traditional reliability testing, the methodology is finding increased usage by appliance manufacturers. In the present study, a simulation-based ALT approach was used to predict the service life of a polyacetal hinge cam from a consumer refrigerator. A predictive life stress model based on cumulative surface wear under accelerated stress conditions was developed and used to predict time to failure under consumer use. Results show that the life stress model demonstrated good agreement with performance testing data and reasonably predicts hinge life
A review of near-wall Reynolds-stress
The advances made in second-order near-wall turbulence closures are summarized. All closures examined are based on some form of high Reynolds number models for the Reynolds stress and the turbulent kinetic energy dissipation rate equations. Consequently, most near-wall closures proposed to data attempt to modify the high Reynolds number models for the dissipation rate equation so that the resultant models are applicable all the way to the wall. The near-wall closures are examined for their asymptotic behavior so that they can be compared with the proper near-wall behavior of the exact equations. A comparison of the closure's performance in the calculation of a low Reynolds number plane channel flow is carried out. In addition, the closures are evaluated for their ability to predict the turbulence statistics and the limiting behavior of the structure parameters compared to direct simulation data
Visual attention for linguistic and non-linguistic body actions in non-signing and native signing children
Evidence from adult studies of deaf signers supports the dissociation between neural systems involved in processing visual linguistic and non-linguistic body actions. The question of how and when this specialization arises is poorly understood. Visual attention to these forms is likely to change with age and be affected by prior language experience. The present study used eye-tracking methodology with infants and children as they freely viewed alternating video sequences of lexical American sign language (ASL) signs and non-linguistic body actions (self-directed grooming action and objectdirected pantomime). In Experiment 1, we quantified fixation patterns using an area of interest (AOI) approach and calculated face preference index (FPI) values to assess the developmental differences between 6 and 11-month-old hearing infants. Both groups were from monolingual English-speaking homes with no prior exposure to sign language. Six-month-olds attended the signer’s face for grooming; but for mimes and signs, they were drawn to attend to the “articulatory space” where the hands and arms primarily fall. Eleven-montholds, on the other hand, showed a similar attention to the face for all body action types. We interpret this to reflect an early visual language sensitivity that diminishes with age, just before the child’s first birthday. In Experiment 2, we contrasted 18 hearing monolingual English-speaking children (mean age of 4.8 years) vs. 13 hearing children of deaf adults (CODAs; mean age of 5.7 years) whose primary language at home was ASL. Native signing children had a significantly greater face attentional bias than non-signing children for ASL signs, but not for grooming and mimes. The differences in the visual attention patterns that are contingent on age (in infants) and language experience (in children) may be related to both linguistic specialization over time and the emerging awareness of communicative gestural acts
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Stylistic Elements within the Texture and Formal Structure of Ernst von Dohnányi's Four Rhapsodies, op. 11
Hungarian pianist, composer, conductor, teacher and administrator, Ernst von Dohnányi (Ernö Dohnányi in Hungarian), was considered one of the most versatile musicians and the first architect of Hungary's musical culture in the late nineteenth and early twentieth-century. Dohnányi composed the Four Rhapsodies, op. 11, between 1902 and 1903, and among his many piano compositions, op. 11 are regarded as some of his most substantial works. Without directly imitating the earlier works of Liszt and Brahms, Dohnányi contributed to the rhapsody tradition with op. 11 by using his own unique stylistic compositional elements in the textural and formal structure. Texture and form are the most indicative characteristics of his rhapsodic language because of the improvisational nature that permeates his compositional style in the rhapsodies. In this dissertation the works are examined from within its textural and formal structure. Within texture, rhythm and accompanimental figurations are examined. Each rhapsody's structural organization, including references to eighteenth-century forms, and the cyclical elements in the work is analyzed. Background information on Dohnányi and a brief history of the rhapsody in the 19th century is also included
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