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61.
Padilla-Parra S Audugé N Coppey-Moisan M Tramier M 《Microscopy research and technique》2011,74(8):788-793
Dual-color fluorescence correlation spectroscopy is an interesting method to quantify protein interaction in living cells. But, when performing these experiments, one must compensate for a known spectral bleed through artifact that corrupts cross-correlation data. In this article, problems with crosstalk were overcome with an approach based on fluorescence lifetime correlation spectroscopy (FLCS). We show that FLCS applied to dual-color EGFP and mCherry cross-correlation allows the determination of protein-protein interactions in living cells without the need of spectral bleed through calibration. The methodology was validated by using EGFP-mCherry tandem in comparison with coexpressed EGFP and mCherry in live cell. The dual-color FLCS experimental procedure where the different laser intensities do not have to be controlled during experiment is really very helpful to study quantitatively protein interactions in live sample. 相似文献
62.
A comparison of broad versus deep auditory menu structures 总被引:1,自引:0,他引:1
OBJECTIVE: The primary purpose of this experiment was to gain a greater understanding of the utilization of working memory when interacting with a speech-enabled interactive voice response (IVR) system. BACKGROUND: A widely promoted guideline advises limiting IVR menus to five or fewer items because of constraints of the human memory system, commonly citing Miller's (1956) paper. The authors argue that Miller's paper does not, in fact, support this guideline. Furthermore, applying modern theories of working memory leads to the opposite conclusion--that reducing menu length by creating a deeper structure is actually more demanding of users' working memories and leads to poorer performance and satisfaction. METHOD: Participants took a working memory capacity test and then attempted to complete a series of e-mail tasks using one of two IVR designs (functionally equivalent, but one with a broad menu structure and the other with a deep structure). RESULTS: Users of the broad-structure IVR performed better and were more satisfied than users of the deep-structure IVR. Furthermore, this effect was more pronounced for those with low working memory capacity. CONCLUSION: Results indicate that creating a deeper structure is more demanding of working memory resource than the alternative of longer, shallower menus. APPLICATION: This experiment has important practical implications for all systems with auditory menus (particularly IVRs) because it provides empirical evidence refuting a widely promoted design practice. 相似文献
63.
Estimation of soil clay and calcium carbonate using laboratory, field and airborne hyperspectral measurements 总被引:2,自引:0,他引:2
Philippe Lagacherie Frédéric Baret José Madeira Netto Jean Marc Robbez-Masson 《Remote sensing of environment》2008,112(3):825-835
This paper examines how reflectance spectrometry used in the laboratory to estimate clay and calcium carbonate (CaCO3) soil contents can be applied to field and airborne measurements for soil property mapping. A continuum removal (CR) technique quantifying specific absorption features of clay (2206 nm) and CaCO3 (2341 nm) was applied to laboratory, field and airborne HYMAP reflectance measurements collected in 2003 (33 sites) and 2005 (19 sites) over bare soil sites of a few meters within the La Peyne Valley area, southern France. Nine intermediate stages from the laboratory up to HYMAP sensor measurements were considered for separately evaluating the possible degradation of estimation performances when going across scales and sensors, e.g. radiometric calibration, spectral resolution, spatial variability, illumination conditions, and surface status including roughness, soil moisture and presence and nature of pebbles.Significant relationships were observed between clay and CaCO3 contents and CR values computed respectively at 2206 nm and 2341 nm from reflectance measurements at the laboratory level with an ASD spectrophotometer up to the HYMAP spectro-imaging sensor. Performances of clay and CaCO3 estimations decreased from the laboratory to airborne scales. The main factors inducing uncertainties in the estimates were radiometric and wavelength calibration uncertainties of the HYMAP sensor as well as possible residual atmospheric effects. 相似文献
64.
Yan J Pollefeys M 《IEEE transactions on pattern analysis and machine intelligence》2008,30(5):865-877
Recovering articulated shape and motion, especially human body motion, from video is a challenging problem with a wide range of applications in medical study, sport analysis and animation, etc. Previous work on articulated motion recovery generally requires prior knowledge of the kinematic chain and usually does not concern the recovery of the articulated shape. The non-rigidity of some articulated part, e.g. human body motion with nonrigid facial motion, is completely ignored. We propose a factorization-based approach to recover the shape, motion and kinematic chain of an articulated object with nonrigid parts altogether directly from video sequences under a unified framework. The proposed approach is based on our modeling of the articulated non-rigid motion as a set of intersecting motion subspaces. A motion subspace is the linear subspace of the trajectories of an object. It can model a rigid or non-rigid motion. The intersection of two motion subspaces of linked parts models the motion of an articulated joint or axis. Our approach consists of algorithms for motion segmentation, kinematic chain building, and shape recovery. It handles outliers and can be automated. We test our approach through synthetic and real experiments and demonstrate how to recover articulated structure with non-rigid parts via a single-view camera without prior knowledge of its kinematic chain. 相似文献
65.
Recent progress in modelling, animation and rendering means that rich, high fidelity virtual worlds are found in many interactive graphics applications. However, the viewer's experience of a 3D world is dependent on the nature of the virtual cinematography, in particular, the camera position, orientation and motion in relation to the elements of the scene and the action. Camera control encompasses viewpoint computation, motion planning and editing. We present a range of computer graphics applications and draw on insights from cinematographic practice in identifying their different requirements with regard to camera control. The nature of the camera control problem varies depending on these requirements, which range from augmented manual control (semi‐automatic) in interactive applications, to fully automated approaches. We review the full range of solution techniques from constraint‐based to optimization‐based approaches, and conclude with an examination of occlusion management and expressiveness in the context of declarative approaches to camera control. 相似文献
66.
Iris Reinbacher Marc Benkert Marc van Kreveld Joseph S. B. Mitchell Jack Snoeyink Alexander Wolff 《Algorithmica》2008,50(3):386-414
In geographic information retrieval, queries often name geographic regions that do not have a well-defined boundary, such
as “Southern France.” We provide two algorithmic approaches to the problem of computing reasonable boundaries of such regions
based on data points that have evidence indicating that they lie either inside or outside the region. Our problem formulation
leads to a number of subproblems related to red-blue point separation and minimum-perimeter polygons, many of which we solve
algorithmically. We give experimental results from our implementation and a comparison of the two approaches.
This research is supported by the EU-IST Project No. IST-2001-35047 (SPIRIT) and by grant WO 758/4-2 of the German Research
Foundation (DFG). 相似文献
67.
Today, laypersons often consult the Internet to inform themselves about health-related issues. However, the competent use of these often complex and heterogeneous information provisions cannot be taken for granted, because many Internet users are lacking the necessary metacognitive prerequisites. Therefore, we developed the metacognitive computer-tool met.a.ware, which supports laypersons’ Internet research for medical information by the means of metacognitive prompting and ontological classification. In an experimental investigation of met.a.ware a total of 118 participants with little medical knowledge were asked to conduct an Internet research on a medical topic. Participants were randomly assigned to four experimental groups that worked with met.a.ware and either received evaluation prompts, monitoring prompts, both types of prompts, or no prompts. All experimental conditions were additionally provided with ontological classification. One control group took paper and pencil notes. A further control group took notes using a blank text window. Results showed that laypersons receiving evaluation prompts outperformed controls in terms of knowledge about sources and produced more arguments commenting on the source of information in an essay task. In addition, laypersons receiving monitoring prompts acquired significantly more knowledge about facts, but did not perform better on a comprehension test than the controls. The availability of ontological categories helped to structure the notes laypersons in the conditions working with ontological classification took during Internet research. Analyses of the notes further demonstrated that the availability of ontological categories guided information search in direction of the selected categories. It is concluded, that met.a.ware is an effective tool that supports laypersons’ Internet research. 相似文献
68.
Van Hulle MM 《Neural computation》2008,20(5):1344-1365
A new gradient technique is introduced for linear independent component analysis (ICA) based on the Edgeworth expansion of mutual information, for which the algorithm operates sequentially using fixed-point iterations. In order to address the adverse effect of outliers, a robust version of the Edgeworth expansion is adopted, in terms of robust cumulants, and robust derivatives of the Hermite polynomials are used. Also, a new constrained version of ICA is introduced, based on goal programming of mutual information objectives, which is applied to the extraction of the antepartum fetal electrocardiogram from multielectrode cutaneous recordings on the mother's thorax and abdomen. 相似文献
69.
Megumi Shinozaki Masato Kusanagi Kazunori Umeda Guy Godin Marc Rioux 《Computer Vision and Image Understanding》2009,113(11):1170-1179
Most active optical range sensors record, simultaneously with the range image, the amount of light reflected at each measured surface location: this information forms what is called a range intensity image, also known as a reflectance image. This paper proposes a method that uses this type of image for the correction of the color information of a textured 3D model. This color information is usually obtained from color images acquired using a digital camera. The lighting condition for the color images are usually not controlled, thus this color information may not be accurate. On the other hand, the illumination condition for the range intensity image is known since it is obtained from a controlled lighting and observation configuration, as required for the purpose of active optical range measurement. The paper describes a method for combining the two sources of information, towards the goal of compensating for a reference range intensity image is first obtained by considering factors such as sensor properties, or distance and relative surface orientation of the measured surface. The color image of the corresponding surface portion is then corrected using this reference range intensity image. A B-spline interpolation technique is applied to reduce the noise of range intensity images. Finally, a method for the estimation of the illumination color is applied to compensate for the light source color. Experiments show the effectiveness of the correction method using range intensity images. 相似文献
70.
Ye Chen Keith W. Hipel D. Marc Kilgour Yuming Zhu 《Environmental Modelling & Software》2009,24(5):647-654
Brownfield redevelopment (BR) is an ongoing issue for governments, communities, and consultants around the world. It is also an increasingly popular research topic in several academic fields. Strategic decision support that is now available for BR is surveyed and assessed. Then a dominance-based rough-set approach is developed and used to classify cities facing BR issues according to the level of two characteristics, BR effectiveness and BR future needs. The data for the classification are based on the widely available results of a survey of US cities. The unique features of the method are its reduced requirement for preference information, its ability to handle missing information effectively, and the easily understood linguistic decision rules that it generates, based on a training classification provided by experts. The resulting classification should be a valuable aid to cities and governments as they plan their BR projects and budgets. 相似文献