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排序方式: 共有214条查询结果,搜索用时 15 毫秒
1.
Paper introduces a 3-D shape representation scheme for automatic face analysis and identification, and demonstrates its invariance to facial expression. The core of this scheme lies on the combination of statistical shape modelling and non-rigid deformation matching. While the former matches 3-D faces with facial expression, the latter provides a low-dimensional feature vector that controls the deformation of model for matching the shape of new input, thereby enabling robust identification of 3-D faces. The proposed scheme is also able to handle the pose variation without large part of missing data. To assist the establishment of dense point correspondences, a modified free-form-deformation based on B-spline warping is applied with the help of extracted landmarks. The hybrid iterative closest point method is introduced for matching the models and new data. The feasibility and effectiveness of the proposed method was investigated using standard publicly available Gavab and BU-3DFE datasets, which contain faces with expression and pose changes. The performance of the system was compared with that of nine benchmark approaches. The experimental results demonstrate that the proposed scheme provides a competitive solution for face recognition. 相似文献
2.
Alexandra Doggett Dustin T. Weiler 《International journal of human-computer interaction》2017,33(4):280-286
ABSTRACTPrevious research on personal health records (PHRs) has focused on applications that are “tethered” to a specific electronic health record (EHR). However, there is a gap in research on the usability of unaffiliated, independent PHRs, as well as research on college-aged PHR users. Therefore, we performed a comparative usability study with 18 college-aged participants on three popular, freely available, independent PHRs. Participants completed the same six tasks in three different PHRs. Dependent variables included task time, mouse movement, mouse clicks, keystrokes, errors, and user satisfaction ratings based on the Computer System Usability Questionnaire (CSUQ). Analysis of variance (ANOVA) was used to determine the significance in the difference of the means for each dependent variable. Results showed statistically significant differences in CSUQ survey categories, errors, and keystrokes. Results supported one of the three PHRs (“System A”) as having better usability than its tested counterparts; participants scored best in System A of all categories of the CSUQ, and used System A with less mouse movement, commission errors, and keystrokes than the other PHRs. 相似文献
3.
The role of nanotopography on the long‐term response of progenitor cells is explored using polycaprolactone (PCL) nanopillar and nanofiber surfaces seeded with plastic‐adherent rat multipotent mesenchymal stromal cells (MSCs). After 4 weeks in culture under normal expansion media conditions, MSCs cultured on nanofibers exhibit better adherence, increased proliferation, and maintain increasingly dense fibroblast‐like morphologies. In contrast, MSCs seeded on nanopillar surfaces display lowered adherence, reduced proliferation, and adopt highly elongated cellular morphologies. Immunofluorescent staining of MSCs on PCL nanopillars reveals the presence of two bone marker proteins, osteopontin and osteocalcin, providing evidence for surface induced differentiation into osteoblast‐like cells. Unlike the nanopillar topography, MSCs cultured on nanofiber and smooth PCL surfaces did not appear to undergo osteogenesis. Observed differences in cellular response to the PCL nanotopographies offer strategies to direct progenitor cell populations solely based upon submicron surface modifications. This study provides a foundation for future work exploring variations in PCL nanopillar topography with the goal of optimizing adherence and osteogenic response of MSCs. 相似文献
4.
The use of composite multiple feedback in a newly proposed virtual reality system enables the patient to perceive similar real-world performance in the virtual world. However, it might cause information overload, which makes the patient feel confused and distracted during training. The aim of this study is to investigate the effectiveness of having separate function-specific feedback pre-training prior to the final multiform feedback task. During the evaluating tests with thirty healthy subjects, it has been found that effective pre-training set could overcome the problem in the main task. Minor modifications on the pre-training set could overcome or aggravate the problem, which indicates the importance of choosing the correct pre-training parameters. 相似文献
5.
Mahshid Fardadi Dustin F. McLartyJacob Brouwer Faryar Jabbari 《International Journal of Hydrogen Energy》2014
We study a counter-flow solid oxide fuel cell system and consider the challenges faced in minimizing thermal variations from the nominal operating conditions for a reasonable range of power tracking. Blower dynamics, reformer transport delays, spatial distribution of the heat generated and the resulting thermal response are among the issues considered. A novel approach, relying on partial internal reformation of the feedstock is proposed as a remedy to maintain a strong level of power tracking with minimal thermal stress to the fuel cell. 相似文献
6.
Sediment and discharge yields within a minimally disturbed,headwater watershed in North Central Pennsylvania,USA, with an emphasis on Superstorm Sandy 下载免费PDF全文
We estimated discharge and suspended sediment (SS) yield in a minimally disturbed watershed in North Central Pennsylvania, USA, and compared a typical storm (September storm, 4.80 cm) to a large storm (Superstorm Sandy, 7.47 cm rainfall). Depending on branch, Sandy contributed 9.7–19.9 times more discharge and 11.5–37.4 times more SS than the September storm. During the September storm, the upper two branches accounted for 60.6% of discharge and 88.8% of SS at Lower Branch; during Sandy these percentages dropped to 36.1% for discharge and 30.1% for SS. The branch with close proximity roads had over two‐three times per area SS yield than the branch without such roads. Hysteresis loops showed typical clockwise patterns for the September storm and more complicated patterns for Sandy, reflecting the multipeak event. Estimates of SS and hysteresis in minimally disturbed watersheds provide useful information that can be compared spatially and temporally to facilitate management. 相似文献
7.
The effect of the anion in the original rare earth element(REE) solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared(ATR-IR) spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy(ICP-MS), and density functional theory(DFT). The simulated IR spectrum at the DFT B3 LYP/6-31 G(d) level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the Dowex 50 W X8. The flow reactor studies reveal the type of solute anion(SO_4~((2-)) or NO_3~((-))) associated with the REE during cation exchange significantly affects the sorption capacity of the Dowex 50 W X8 ion exchange resin. The calculated REE binding energy(BE) and the DFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2~((3+))2 SO_4~((2-)) and Ce~((3+)) 3 NO_3~((-)). These results suggest that the solute anion affects the equilibrium constants of the Dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site(H+) in the Dowex 50 W X8 with the NH_4~+ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the Dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb. 相似文献
8.
Software and Systems Modeling - Engineers commonly use paper and whiteboards to sketch and discuss ideas in early phases of requirements elicitation and software modeling. These physical media... 相似文献
9.
Sheldon T. Bailey Gretchen E. Lokey Melinda S. Hanes John D.M. Shearer Jason B. McLafferty Gregg T. Beaumont Timothy T. Baseler Joshua M. Layhue Dustin R. Broussard Yu-Zhong Zhang Bruce P. Wittmershaus 《Solar Energy Materials & Solar Cells》2007,91(1):67-75
The spectral range of sunlight absorbed by a luminescent solar concentrator (LSC) is increased by using multiple dyes. Absorption, fluorescence, and fluorescence excitation spectra, and relative light output are reported for LSCs made with one, two, or three BODIPY dyes in a thin polymer layer on glass. Losses caused by multiple emission and reabsorption events are minimized by optimizing resonance excitation energy transfer between dyes. Increases in the outputs from the multiple-dye LSCs are directly proportional to increases in the number of photons absorbed. The output of the three-dye LSC is 45–170% higher than those of the single-dye LSCs. 相似文献
10.
Lik-Kwan Shark Author Vitae Andrey A. Kurekin Author Vitae Author Vitae 《Pattern recognition》2007,40(5):1432-1450
By extending the previously proposed geometric branch-and-bound algorithm with bounded alignment for point pattern matching, the paper presents the development and evaluation of a new and fast algorithm for image registration based on line segments. Using synthetically generated data sets with randomly distributed line segments and hard test cases with highly symmetric line patterns, as well as real remote sensing images, the developed algorithm is shown to be computationally fast, highly robust, capable of handling severely corrupted data sets with considerable line segment position errors as well as significant fragmented and spurious line segments in the images to be matched. 相似文献