Institution
University of Waterloo
Education•Waterloo, Ontario, Canada•
About: University of Waterloo is a education organization based out in Waterloo, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 36093 authors who have published 93906 publications receiving 2948139 citations. The organization is also known as: UW & uwaterloo.
Papers published on a yearly basis
Papers
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20 Apr 2002TL;DR: Results show that cost-benefit tradeoffs are a key consideration in the adoption of UCD methods and that there is a major discrepancy between the commonly cited measures and the actually applied ones.
Abstract: This paper reports the results of a recent survey of user-centered design (UCD) practitioners. The survey involved over a hundred respondents who were CHI'2000 attendees or current UPA members. The paper identifies the most widely used methods and processes, the key factors that predict success, and the critical tradeoffs practitioners must make in applying UCD methods and processes. Results show that cost-benefit tradeoffs are a key consideration in the adoption of UCD methods. Measures of UCD effectiveness are lacking and rarely applied. There is also a major discrepancy between the commonly cited measures and the actually applied ones. These results have implications for the introduction, deployment, and execution of UCD projects
672 citations
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TL;DR: In this article, the color distribution of 24,346 galaxies drawn from the Sloan Digital Sky Survey first data release, as a function of luminosity and environment, was analyzed and a weakly significant (3 σ) detection of a trend for colors to become redder by 0.1-0.14 was made, with a factor of ~100 increase in local density, as characterized by the surface density of galaxies within a ±1000 km s-1 redshift slice.
Abstract: We analyze the u - r color distribution of 24,346 galaxies with Mr ≤ -18 and z < 0.08, drawn from the Sloan Digital Sky Survey first data release, as a function of luminosity and environment. The color distribution is well fitted with two Gaussian distributions, which we use to divide the sample into a blue and red population. At fixed luminosity, the mean color of the blue (red) distribution is nearly independent of environment, with a weakly significant (~3 σ) detection of a trend for colors to become redder by 0.1-0.14 (0.03-0.06) mag with a factor of ~100 increase in local density, as characterized by the surface density of galaxies within a ±1000 km s-1 redshift slice. In contrast, at fixed luminosity the fraction of galaxies in the red distribution is a strong function of local density, increasing from ~10%-30% of the population in the lowest density environments to ~70% at the highest densities. The strength of this trend is similar for both the brightest (-23 < Mr < -22) and faintest (-19 < Mr < -18) galaxies in our sample. The fraction of red galaxies within the virialized regions of clusters shows no significant dependence on velocity dispersion. Even at the lowest densities explored, a substantial population of red galaxies exists, which might be fossil groups. We propose that most star-forming galaxies today evolve at a rate that is determined primarily by their intrinsic properties and independent of their environment. Any environmentally triggered transformations from blue to red colors must occur either on a short timescale or preferentially at high redshift to preserve the simple Gaussian nature of the color distribution. The mechanism must be effective for both bright and faint galaxies.
669 citations
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TL;DR: In this paper, the authors discuss the relationship between developmental dyslexia and slow symbol naming speed and argue that an understanding of this precise timing dimension is necessary to incorporate in our models of phonological, orthographic, and semantic processes in reading acquisition and reading failure.
Abstract: In this paper, we review several lines of convergent research to discuss the relationship between developmental dyslexia and slow symbol naming speed. We describe the interactive development of orthographic and phonological codes, and we discuss the methodological problems that may have led to underestimating the importance of individual differences in orthographic processing in our account of reading disabilities. Symbol naming speed is typically subsumed under phonological processing, yet it contributes variance to reading, especially to reading fluency, independently of phonological awareness. We speculate that naming speed may reflect precise timing mechanisms necessary to the development of orthographic codes and to their integration with phonological codes. We argue that an understanding of this precise timing dimension is necessary to incorporate in our models of phonological, orthographic, and semantic processes in reading acquisition and reading failure.
667 citations
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TL;DR: This work model the output of the computer code as the realization of a stochastic process, allowing nonlinear and interaction effects to emerge without explicitly modeling such effects.
Abstract: Many scientific phenomena are now investigated by complex computer models or codes. Given the input values, the code produces one or more outputs via a complex mathematical model. Often the code is expensive to run, and it may be necessary to build a computationally cheaper predictor to enable, for example, optimization of the inputs. If there are many input factors, an initial step in building a predictor is identifying (screening) the active factors. We model the output of the computer code as the realization of a stochastic process. This model has a number of advantages. First, it provides a statistical basis, via the likelihood, for a stepwise algorithm to determine the important factors. Second, it is very flexible, allowing nonlinear and interaction effects to emerge without explicitly modeling such effects. Third, the same data are used for screening and building the predictor, so expensive runs are efficiently used. We illustrate the methodology with two examples, both having 20 input variables. I...
663 citations
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TL;DR: Two broad families of surrogates namely response surface surrogates, which are statistical or empirical data‐driven models emulating the high‐fidelity model responses, and lower‐f fidelity physically based surrogates which are simplified models of the original system are detailed in this paper.
Abstract: [1] Surrogate modeling, also called metamodeling, has evolved and been extensively used over the past decades. A wide variety of methods and tools have been introduced for surrogate modeling aiming to develop and utilize computationally more efficient surrogates of high-fidelity models mostly in optimization frameworks. This paper reviews, analyzes, and categorizes research efforts on surrogate modeling and applications with an emphasis on the research accomplished in the water resources field. The review analyzes 48 references on surrogate modeling arising from water resources and also screens out more than 100 references from the broader research community. Two broad families of surrogates namely response surface surrogates, which are statistical or empirical data-driven models emulating the high-fidelity model responses, and lower-fidelity physically based surrogates, which are simplified models of the original system, are detailed in this paper. Taxonomies on surrogate modeling frameworks, practical details, advances, challenges, and limitations are outlined. Important observations and some guidance for surrogate modeling decisions are provided along with a list of important future research directions that would benefit the common sampling and search (optimization) analyses found in water resources.
663 citations
Authors
Showing all 36498 results
Name | H-index | Papers | Citations |
---|---|---|---|
John J.V. McMurray | 178 | 1389 | 184502 |
David A. Weitz | 178 | 1038 | 114182 |
David Taylor | 131 | 2469 | 93220 |
Lei Zhang | 130 | 2312 | 86950 |
Will J. Percival | 129 | 473 | 87752 |
Trevor Hastie | 124 | 412 | 202592 |
Stephen Mann | 120 | 669 | 55008 |
Xuan Zhang | 119 | 1530 | 65398 |
Mark A. Tarnopolsky | 115 | 644 | 42501 |
Qiang Yang | 112 | 1117 | 71540 |
Wei Zhang | 112 | 1189 | 93641 |
Hans-Peter Seidel | 112 | 1213 | 51080 |
Theodore S. Rappaport | 112 | 490 | 68853 |
Robert C. Haddon | 112 | 577 | 52712 |
David Zhang | 111 | 1027 | 55118 |