- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Perceptually Validated Cross-Renderer Analytical BRDF Parameter Remapping
摘要： Material appearance of rendered objects depends on the underlying BRDF implementation used by rendering software packages. A lack of standards to exchange material parameters and data (between tools) means that artists in digital 3D prototyping and design, manually match the appearance of materials to a reference image. Since their effect on rendered output is often non-uniform and counter intuitive, selecting appropriate parameterisations for BRDF models is far from straightforward. We present a novel BRDF remapping technique, that automatically computes a mapping (BRDF Difference Probe) to match the appearance of a source material model to a target one. Through quantitative analysis, four user studies and psychometric scaling experiments, we validate our remapping framework and demonstrate that it yields a visually faithful remapping among analytical BRDFs. Most notably, our results show that even when the characteristics of the models are substantially different, such as in the case of a phenomenological model and a physically-based one, our remapped renderings are indistinguishable from the original source model.
关键词： BRDF model,Virtual Materials,Perceptual validation,Surface perception
更新于2025-09-09 09:28:46
-
[IEEE 2018 IEEE Western New York Image and Signal Processing Workshop (WNYISPW) - Rochester, NY, USA (2018.10.5-2018.10.5)] 2018 IEEE Western New York Image and Signal Processing Workshop (WNYISPW) - Nonsingular Gaussian Conditionally Markov Sequences
摘要： Markov processes are widely used in modeling random phenomena/problems. However, they may not be adequate in some cases where more general processes are needed. The conditionally Markov (CM) process is a generalization of the Markov process based on conditioning. There are several classes of CM processes (one of them is the class of reciprocal processes), which provide more capability (than Markov) for modeling random phenomena. Reciprocal processes have been used in many different applications (e.g., image processing, intent inference, intelligent systems). In this paper, nonsingular Gaussian (NG) CM sequences are studied, characterized, and their dynamic models are presented. The presented results provide effective tools for studying reciprocal sequences from the CM viewpoint, which is different from that of the literature. Also, the presented models and characterizations serve as a basis for application of CM sequences, e.g., in motion trajectory modeling with destination information.
关键词： dynamic model,Gaussian sequence,characterization,Conditionally Markov (CM) sequence
更新于2025-09-09 09:28:46
-
Raman and infrared spectroscopy reveal that proliferating and quiescent human fibroblast cells age by biochemically similar but not identical processes
摘要： Dermal fibroblast cells can adopt different cell states such as proliferation, quiescence, apoptosis or senescence, in order to ensure tissue homeostasis. Proliferating (dividing) cells pass through the phases of the cell cycle, while quiescent and senescent cells exist in a non-proliferating cell cycle-arrested state. However, the reversible quiescence state is in contrast to the irreversible senescence state. Long-term quiescent cells transit into senescence indicating that cells age also when not passing through the cell cycle. Here, by label-free in vitro vibrational spectroscopy, we studied the biomolecular composition of quiescent dermal fibroblast cells and compared them with those of proliferating and senescent cells. Spectra were examined by multivariate statistical analysis using a PLS-LDA classification model, revealing differences in the biomolecular composition between the cell states mainly associated with protein alterations (variations in the side chain residues of amino acids and protein secondary structure), but also within nucleic acids and lipids. We observed spectral changes in quiescent compared to proliferating cells, which increased with quiescence cultivation time. Raman and infrared spectroscopy, which yield complementary biochemical information, clearly distinguished contact-inhibited from serum-starved quiescent cells. Furthermore, the spectra displayed spectral differences between quiescent cells and proliferating cells, which had recovered from quiescence. This became more distinct with increasing quiescence cultivation time. When comparing proliferating, (in particular long-term) quiescent and senescent cells, we found that Raman as well as infrared spectroscopy can separate these three cellular states from each other due to differences in their biomolecular composition. Our spectroscopic analysis shows that proliferating and quiescent fibroblast cells age by similar but biochemically not identical processes. Despite their aging induced changes, over long time periods quiescent cells can return into the cell cycle. Finally however, the cell cycle arrest becomes irreversible indicating senescence.
关键词： PLS-LDA classification model,Raman spectroscopy,infrared spectroscopy,quiescence,senescence,proliferation,fibroblast cells,biomolecular composition
更新于2025-09-09 09:28:46
-
Study on a Twice Transfer Alignment Based on Dual Model
摘要： This paper proposes a twice rapid transfer alignment algorithm based on dual models in order to solve the problems such as long convergence time, poor accuracy, and heavy computation burden resulting from the traditional nonlinear error models. The quaternion matching method based on quaternion error model along with the extended Kalman filter (EKF) is applied to deal with the large misalignment in the first phase. Then in the second transfer alignment phase, velocity plus attitude matching method as well as classical Kalman filter is adopted. The simulation and the results of vehicle tests demonstrate that this method combines the advantages of both nonlinear and linear error models with the guarantee of accuracy and fastness.
关键词： quaternion error model,extended Kalman filter,transfer alignment,dual models,velocity plus attitude matching
更新于2025-09-09 09:28:46
-
Image Reconstruction Using Analysis Model Prior
摘要： The analysis model has been previously exploited as an alternative to the classical sparse synthesis model for designing image reconstruction methods. Applying a suitable analysis operator on the image of interest yields a cosparse outcome which enables us to reconstruct the image from undersampled data. In this work, we introduce additional prior in the analysis context and theoretically study the uniqueness issues in terms of analysis operators in general position and the specific 2D finite difference operator. We establish bounds on the minimum measurement numbers which are lower than those in cases without using analysis model prior. Based on the idea of iterative cosupport detection (ICD), we develop a novel image reconstruction model and an effective algorithm, achieving significantly better reconstruction performance. Simulation results on synthetic and practical magnetic resonance (MR) images are also shown to illustrate our theoretical claims.
关键词： cosparsity,iterative cosupport detection,magnetic resonance imaging,analysis model,image reconstruction
更新于2025-09-09 09:28:46
-
P-1.11: A Compact Model of Current and Capacitance for Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors
摘要： In recent years, amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) have shown outstanding performance in flexible circuit applications, active matrix display and so on. Therefore, they will play an increasingly important role in the future of electronic applications. At the same time, an analytical model that predicts the electrical characteristics of IGZO TFTs is also critical. In this paper, we present a current and capacitance compact model of a-IGZO TFTs. The compact model can be applied to different channel lengths for a-IGZO TFTs. Besides, it is capable of capturing device characteristics and of maintaining high computational efficiency. Its accuracy is validated through the extensive comparisons between model results and experimental data.
关键词： degenerate mechanism,AC model,Amorphous IGZO thin-film transistors,DC model
更新于2025-09-04 15:30:14
-
Total Global Solar Radiation Estimation with Relative Humidity and Air Temperature Extremes in Ireland and Holland
摘要： Solar radiation is the earth’s primary energy source for all biochemical and physical activities. Accurate knowledge of the solar radiation is important in engineering applications. This study aimed to calibrate some of the existing models in the literature for estimating daily total global solar radiation parameter using available measuring records (maximum and minimum air temperatures) and new models were developed based on maximum and minimum air temperatures, relative humidity and relative humidity extremes. Applicability of the Hargreaves model, Allen model, Bristow-Campbell model and Chen model were evaluated for computing the daily total solar global radiation, the geographical and meteorological data of Irish and Dutch cities were used. Meteorological data were taken from Royal Netherlands Meteorological Institute and Irish Meteorological Service. The models were compared on the basis of error tests which were mean percentage error (MPE), mean bias error (MBE), root mean square error (RMSE) and Nash-Sutcliffe equation (NSE). And, monthly MPE errors were given for each model. This study proposed new estimation models which were based on daily average relative humidity, relative humidity extremes and temperature extremes. Error analyses were applied to these models and results were given in the study.
关键词： Holland,solar radiation,model validation,temperature,daily total global solar radiation,relative humidity,model comparison,Ireland,meteorological models
更新于2025-09-04 15:30:14
-
High-order above-threshold ionization beyond the electric dipole approximation: Dependence on the atomic and molecular structure
摘要： We provide an in-depth analysis of high-order above-threshold ionization of atoms and molecules by strong laser pulses, using three different theoretical approaches beyond the electric dipole approximation: (i) the numerical solution of the time-dependent Schr?dinger equation, (ii) the classical three-step model, and (iii) the quantum-orbit model. In the classical and quantum-orbit models, we include an accurate description of the rescattering step by target-specific differential scattering cross sections. The considerable forward shift of the photoelectron momentum distributions along the laser propagation direction can be understood in terms of the nondipole electron motion after rescattering. An explanation of the additionally observed forward-backward asymmetry of the signal strength requires the accurate modeling of the rescattering step and the electron dynamics before the rescattering event. For the H2+ molecular ion, we compare the cases of parallel and perpendicular alignment of the molecular axis and we show that the interference pattern and its modification due to the nondipole effects are orientation dependent. Compared to atoms, the nondipole effects in molecular high-order above-threshold ionization appear more pronounced and amenable to experimental observation.
关键词： high-order above-threshold ionization,nondipole effects,photoelectron momentum distributions,quantum-orbit model,classical three-step model,H2+ molecular ion,electric dipole approximation,time-dependent Schr?dinger equation
更新于2025-09-04 15:30:14
-
Organ- on -a- chip technologies that can transform ophthalmic drug discovery and disease modeling
摘要： Introduction: Disorders of the eye that lead to visual impairment are affecting millions of people worldwide. Nevertheless, for many of these disorders, there are still no effective treatment options available due to the lack of in vitro model systems that emulate the physiological in vivo structure and function of human eyes. Microphysiological organ-on-a-chip (OoC) technology represents a novel and powerful approach to overcome the limitations of conventional model systems and lead to a paradigm shift in ophthalmic research. Areas covered: This review provides an overview of the various tissues of interest in ophthalmology and summarizes existing model systems, including their applications and limitations. Additionally, novel OoC systems with applications in ophthalmology are described and the advantages of these systems compared to conventional models are highlighted. Expert opinion: The physiological relevance of the first ophthalmic OoC systems that mimic human ocular compartments, such as the cornea and retina, has been successfully demonstrated in recent years. There is a great potential for the application of these platforms for future pharmacological target identification, safety, and efficacy testing, as well as personalized medicine. Further improvements and the development of new systems are of upmost importance, especially to model complex disorders affecting several tissues.
关键词： ophthalmic model,microphysiological system,retina-on-a-chip,ocular model,Cornea-on-a-chip,in-vitro models,organ-on-a-chip
更新于2025-09-04 15:30:14
-
[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Path loss model modification for various gains and directions of antennas
摘要： Emerging telecommunication technologies like 5G, green communications, and massive MIMO contribute to the use of directional antennas and beamforming. For this reason, modern propagation models consider directional antennas with different beam widths, gains and radiation pattern directions. Most of the available propagation models are based on omnidirectional or isotropic antennas. A proposition to solve this problem is an empirical path loss model that considers the different types of antennas. This model assumes that the transmitting and receiving antenna beams are directing each other. In this paper, we propose modifying this model by determining attenuation for any direction of the antenna patterns. For this aim, the multi-elliptic channel model is used.
关键词： gain,non-line-of-sight conditions,directional antenna,multipath propagation,multi-elliptical channel model,antenna pattern,channel modeling,path loss model
更新于2025-09-04 15:30:14