Dynamic Shadow Research Articles

Dynamic facade module prototype development for solar radiation prevention in high rise building

Solar radiation is an aspect that high rise building must avoid. The problem is, if high rise building facade can’t overcome, the solar thermal will come in the building, and its affects on the increasing of room temperature above comfort range. A type of additional facade element that could solve solar thermal in high rise building is adding a sun shading. A dynamic facade is a shade plane in high rise building that can moved or changed on outside condition such as solar movement and intensity. This research will discuss the dynamic facade module prototype development in high rise building in Jakarta. This research will be finish through some step. (1) Static shading shadow simulation. (2) Dynamic facade concept design development. (3) Dynamic shading shadow simulation. (4) Making of dynamic facade module prototype. (5) Field test for the dynamic facade module prototype. The dynamic facade in Jakarta case will be effective to solve solar transmission in high rise building rather than static facade.

Examining the economic performance of Chinese farms: A dynamic efficiency and adjustment cost approach

To understand the state of adjustment processes and the dynamic structure in Chinese agriculture, this paper proposes a dynamic frontier-based model using the shadow cost approach. For this purpose, a dynamic duality model framework of inter-temporal decision making is used. Using a panel data set of 4,201 Chinese farms from three provinces (i.e. Zhejiang, Hubei and Yunnan) from 2003 to 2006, this is the first study to investigate the allocative and technical efficiencies of Chinese agriculture using a dynamic shadow cost approach. The findings show that the adjustment of quasi-fixed inputs is rather sluggish, implying that adjustment costs are considerably high on Chinese farms. The relatively low levels of allocative and technical efficiencies indicate that most farms are unable to catch up with the production frontier under the existing production technology. They are also unable to use various inputs in the appropriate proportion given their respective prices.

Background-Foreground Modeling Based on Spatiotemporal Sparse Subspace Clustering.

Background estimation and foreground segmentation are important steps in many high-level vision tasks. Many existing methods estimate background as a low-rank component and foreground as a sparse matrix without incorporating the structural information. Therefore, these algorithms exhibit degraded performance in the presence of dynamic backgrounds, photometric variations, jitter, shadows, and large occlusions. We observe that these backgrounds often span multiple manifolds. Therefore, constraints that ensure continuity on those manifolds will result in better background estimation. Hence, we propose to incorporate the spatial and temporal sparse subspace clustering into the robust principal component analysis (RPCA) framework. To that end, we compute a spatial and temporal graph for a given sequence using motion-aware correlation coefficient. The information captured by both graphs is utilized by estimating the proximity matrices using both the normalized Euclidean and geodesic distances. The low-rank component must be able to efficiently partition the spatiotemporal graphs using these Laplacian matrices. Embedded with the RPCA objective function, these Laplacian matrices constrain the background model to be spatially and temporally consistent, both on linear and nonlinear manifolds. The solution of the proposed objective function is computed by using the linearized alternating direction method with adaptive penalty optimization scheme. Experiments are performed on challenging sequences from five publicly available datasets and are compared with the 23 existing state-of-the-art methods. The results demonstrate excellent performance of the proposed algorithm for both the background estimation and foreground segmentation.

Mixed mode dynamic crack-fiber bundle interaction using caustics

Caustic method was extended to study the interaction between the mixed mode dynamic matrix crack and the fiber bundle in fiber reinforced composites. First, the dynamic caustic experiments were conducted using transparent specimens with different thicknesses of fiber bundles under dynamic three point bending load. Then, the evolutions of dynamic shadow spots at the crack tip shielded by different thicknesses of fiber bundles were obtained. Moreover, the dynamic stress intensity factors were extracted from the shadow spots. Finally, the crack propagation and bifurcation behaviors were analyzed. It was shown that the stress intensity factors and crack propagation velocities were shielded by the fiber bundles, and the shielding effect increased with the increase of fiber bundle thickness.

Outage Performance of Decode-and-Forward Cooperative Networks Over Nakagami-<inline-formula> <tex-math notation="LaTeX">$m$ </tex-math> </inline-formula> Fading With Node Blockage

In this paper, we present an analysis of the outage performance of noise limited uncoordinated decode-and-forward cooperative networks over Nakagami- ${m}$ fading channels. We treat the general case of non-identically distributed internode and uplink fading channels with novel analytical closed-form expressions for the outage probability, derived for the case of integer-valued fading parameter over uplink. A node blockage model is incorporated to characterize dynamic macroscopic shadowing and node failure. We study the simultaneous effects of network size, average signal-to-noise ratio (SNR) over internode and uplink channels, fading severity, and probability of blockage on outage performance. We also study the asymptotic behavior of the outage probability in the high average SNR values and small blockage probabilities. The existence of an irreducible outage probability is identified for cases with node blockage. The results illustrate that the effect of blockage on outage performance is stronger in networks with larger size and at high SNR. The analytical results are confirmed by numerical simulations, and by analytical reduction to published results for special cases of system and channel parameters.

A framework for moving object segmentation using dynamic background modelling and shadow suppression in complex wavelet domain

In this paper, a framework for dynamic background modelling and shadow suppression under rapidly changing illumination conditions for moving object segmentation in complex wavelet domain is proposed which deals with the problems of ghosts, object shadows, noise, object distortion in dynamic background changes. The proposed method consists of eight steps applied on given video frames which include: wavelet de-composition of frame using complex wavelet transform; use of change detection on detail coefficients; use of dynamic background modelling on approximate co-efficient; cast shadow suppression; use of soft thresholding for noise removal; strong edge detection; inverse wavelet transformation for reconstruction and finally using closing morphology operator. A comparative analysis of the proposed method is presented both qualitatively and quantitatively with other standard methods available in the literature for four datasets in terms of various performance measures. Experimental results demonstrate the efficacy of the proposed method is better in terms of relative foreground area measure, misclassification penalty, relative position based measure, normalised cross-correlation, normalised absolute error, peak signal-to-noise ratio and pixel classification based measure as compared to other standard methods.

Framework for dynamic background modeling and shadow suppression for moving object segmentation in complex wavelet domain

Moving object segmentation using change detection in wavelet domain under continuous variations of lighting condition is a challenging problem in video surveillance systems. There are several methods proposed in the literature for change detection in wavelet domain for moving object segmentation having static backgrounds, but it has not been addressed effectively for dynamic background changes. The methods proposed in the literature suffer from various problems, such as ghostlike appearance, object shadows, and noise. To deal with these issues, a framework for dynamic background modeling and shadow suppression under rapidly changing illumination conditions for moving object segmentation in complex wavelet domain is proposed. The proposed method consists of eight steps applied on given video frames, which include wavelet decomposition of frame using complex wavelet transform; use of change detection on detail coefficients (LH, HL, and HH), use of improved Gaussian mixture-based dynamic background modeling on approximate coefficient (LL subband); cast shadow suppression; use of soft thresholding for noise removal; strong edge detection; inverse wavelet transformation for reconstruction; and finally using closing morphology operator. A comparative analysis of the proposed method is presented both qualitatively and quantitatively with other standard methods available in the literature for six datasets in terms of various performance measures. Experimental results demonstrate the efficacy of the proposed method.

Video Object Classification System with Shadow Removal using Gaussian Mixture Model

Classification is the process of assigning a class to a group of objects. Moving objects classification can be difficult a task in the presence of dynamic factors like occlusion clutters and shadows. This paper developed a classifier for moving images (video stream) by using a modified adaptive background mixture model method. This system removes shadows and correctly classifies moving objects as human, human group and vehicles. Background Mixture Model is common technique used in Computer Vision, Video object classification is not an exception, many background models have been designed to address different problems ranging from slow start and shadow removal; this paper presents a method which models each pixel as a mixture of Gaussians and using a Maximum A Posteriori approximation to update the model, this paper also introduces a two level shadow removal technique which suppressed shadows in colour and texture consistencies in the classified objects so that the system will not mis- classify moving shadows as objects. This work overcome the problem of slow learning in busy environment and can classify more than one object in view of the camera

Spatially graded TiO₂-SiO₂ Bragg reflector with rainbow-colored photonic band gap.

A simple single-step method to fabricate spatially graded TiO2-SiO2 Bragg stack with rainbow colored photonic band gap is presented. The gradation in thickness of the Bragg stack was accomplished with a modified glancing angle deposition (GLAD) technique with dynamic shadow enabled by a block attached to one edge of the rotating substrate. A linear gradation in thickness over a distance of about 17 mm resulted in a brilliant colorful rainbow pattern. Interestingly, the photonic band gap position can be changed across the whole visible wavelength range by linearly translating the graded Bragg stack over a large area substrate. The spatially graded Bragg stack may find potential applications in the tunable optical devices, such as optical filters, reflection gratings, and lasers.

Shadow elimination and vehicles classification approaches in traffic video surveillance context

Video surveillance on highway is a hot topic and a great challenge in Intelligent Transportation Systems. In such applications requiring objects extraction, cast shadows induce shape distortions and object fusions interfering performance of high level algorithms. Shadow elimination allows to improve the performances of video object extraction, classification and tracking. In other hand, it is very important to recognize the type of a detected object in order to track reliably and estimate traffic parameters correctly. This paper presents two approaches to enhance automatic traffic surveillance systems. The first deals with the elimination of shadows and the second concerns the classification of vehicles, based on robust vision and image processing. For moving shadow elimination, a contrast model is proposed to describe and remove dynamic shadows based on the idea that a shadow transformation is a change in contrast. For vehicles classification, Hu moments are calculated in a manner to reduce the perspective effects and used to describe vehicles in knowledge base. Experimental results on the various challenging video sequences show that the proposed approach outperforms classification methods of related works (with a classification accuracy of 96.96%), and that the shadow elimination approach performs better than compared works (with detection rate of 95–99% and discrimination rate of 85.7–89%).

Nanohelices by shadow growth.

The helix has remarkable qualities and is prevalent in many fields including mathematics, physics, chemistry, and biology. This shape, which is chiral by nature, is ubiquitous in biology with perhaps the most famous example being DNA. Other naturally occurring helices are common at the nanoscale in the form of protein secondary structures and in various macromolecules. Nanoscale helices exhibit a wide range of interesting mechanical, optical, and electrical properties which can be intentionally engineered into the structure by choosing the correct morphology and material. As technology advances, these fabrication parameters can be fine-tuned and matched to the application of interest. Herein, we focus on the fabrication and properties of nanohelices grown by a dynamic shadowing growth method combined with fast wafer-scale substrate patterning which has a number of distinct advantages. We review the fabrication methodology and provide several examples that illustrate the generality and utility of nanohelices shadow-grown on nanopatterns.

Influence of Dynamic Shadowing on 2D and 3D Laparoscopic Visualization Under Visible Light and Infrared Light

Depth perception is a significant weakness in conventional two-dimensional (2D) endoscopy. We hypothesize that dynamic shadowing improves endoscopic depth perception during laparoscopy. Two experiments were performed to investigate this hypothesis. The first experiment compared the effect of dynamic shadowing with 2D and three-dimensional (3D) displays. The second experiment compared the effect of dynamic shadowing under visible light and infrared light. In the experiment, a box trainer was designed and built to house three laparoscopic tasks. Six settings were investigated: 2D display without dynamic shadows under visible light, 2D display with dynamic shadows under visible light, 3D display without dynamic shadows under visible light, 3D display with dynamic shadows under visible light, 2D display without dynamic shadows under infrared light, and 2D display with dynamic shadows under infrared light. Two types of illumination were used: static overhead illumination and dynamic grasper illumination. The execution time and number of errors committed by the volunteers with no formal laparoscopic experience were measured in the experiments. The experimental results showed that dynamic shadowing with 2D display under both visible light and infrared light reduced mean execution time. Dynamic shadowing with 3D display increased execution time for one of the tasks and increased the number of errors for all three tasks. Dynamic shadowing has the potential to be an inexpensive method to improve laparoscopic depth perception. However, subjects needed to pay special attention to the shadows, which suggests that better implementation is necessary to improve the dominance of shadows as an effective depth cue.

The effect of shear strength on the ballistic response of laminated composite plates

Abstract The ballistic performance of clamped circular carbon fibre reinforced polymer (CFRP) and Ultra High Molecular Weight Polyethylene (UHMWPE) fibre composite plates of equal areal mass and 0/90° lay-up were measured and compared with that of monolithic 304 stainless steel plates. The effect of matrix shear strength upon the dynamic response was explored by testing: (i) CFRP plates with both a cured and uncured matrix and (ii) UHMWPE laminates with identical fibres but with two matrices of different shear strength. The response of these plates when subjected to mid-span, normal impact by a steel ball was measured via a dynamic high speed shadow moire technique. Travelling hinges emanate from the impact location and travel towards the supports. The anisotropic nature of the composite plate results in the hinges travelling fastest along the fibre directions and this results in square-shaped moire fringes in the 0/90° plates. Projectile penetration of the UHMWPE and the uncured CFRP plates occurs in a progressive manner, such that the number of failed plies increases with increasing velocity. The cured CFRP plate, of high matrix shear strength, fails by cone-crack formation at low velocities, and at higher velocities by a combination of cone-crack formation and communition of plies beneath the projectile. On an equal areal mass basis, the low shear strength UHMWPE plate has the highest ballistic limit followed by the high matrix shear strength UHMWPE plate, the uncured CFRP, the steel plate and finally the cured CFRP plate. We demonstrate that the high shear strength UHMWPE plate exhibits Cunniff-type ballistic limit scaling. However, the observed Cunniff velocity is significantly lower than that estimated from the laminate properties. The data presented here reveals that the Cunniff velocity is limited in its ability to characterise the ballistic performance of fibre composite plates as this velocity is independent of the shear properties of the composites: the ballistic limit of fibre composite plates increases with decreasing matrix shear strength for both CFRP and UHMWPE plates.

Visual realism enhances realistic response in an immersive virtual environment--part 2.

Does realistic lighting in an immersive VR application enhance presence--that is, the participants' feeling that they're actually in the scene and behaving accordingly? Part 1 of this study indicated that presence is more likely with real-time ray tracing than with ray casting. However, that research couldn't separate the effects of overall illumination quality from the dynamic effects of real-time shadows and reflections. In a new experiment, 20 people experienced a scene rendered with either global or local illumination. Both conditions included dynamically changing shadows and reflections. Illumination quality didn't affect presence, so the earlier result must have been caused by dynamic shadows and reflections. Nevertheless, global illumination did result in greater plausibility--that is, participants were more likely to respond as if the virtual events were real. These results indicate that global illumination does affect participant responses and is worth the effort.

Nuclear modification of high transverse momentum particle production in p + A collisions at RHIC and LHC

We present results and predictions for the nuclear modification of the differential cross sections for inclusive light hadron and prompt photon production in minimum bias d+Au collisions at s=200 GeV and minimum bias p+Pb collisions at s=5 TeV at RHIC and LHC, respectively. Our calculations combine the leading order perturbative QCD formalism with cold nuclear matter effects that arise from the elastic, inelastic and coherent multiple scattering of partons in large nuclei. We find that a theoretical approach that includes the isospin effect, Cronin effect, cold nuclear matter energy loss and dynamical shadowing can describe the RHIC d+Au data rather well. The LHC p+Pb predictions will soon be confronted by new experimental results to help clarify the magnitude and origin of cold nuclear matter effects and facilitate precision dense QCD matter tomography.

Dynamic Shadow Generation System Based on Shape Recognition

This paper proposes a dynamic shadow generation system that combines the shadow of an object with the artificial shadows of virtual characters. In our proposed system, infrared light is used to capture an object’s shadow in order to discriminate between a shadow generated by an object and a virtual shadow generated by the system. Our proposed system determines areas in which shadows do not appear and then the shadows of virtual characters are added to these areas. This paper presents the basic idea of the system, the shadow generation algorithm that it uses, and an empirical study on the sharpness of a generated shadow, along with the distance between an object and a screen used in this system.

Estimation of Allocative Inefficiency and Productivity Growth with Dynamic Adjustment Costs

A substantial literature has been generated on the estimation of allocative and technical inefficiency using static production, cost, profit, and distance functions. We develop a dynamic shadow distance system that integrates dynamic adjustment costs into a long-run shadow cost-minimization problem, which allows us to distinguish static allocative distortions from short-run inefficiencies that arise due to period-to-period adjustment costs. The set of estimating equations is comprised of the first-order conditions from the short-run shadow cost-minimization problem for the variable shadow input quantities, a set of Euler equations derived from subsequent shadow cost minimization with respect to the quasi-fixed inputs, and the input distance function, expressed in terms of shadow quantities. This system nests within it the static model with zero adjustment costs. Using panel data on U.S. electric utilities, we contrast the results of static and dynamic shadow distance systems. First, the zero-adjustment-cost restriction is strongly rejected. Second, we find that adjustment costs represent about 0.42% of total cost, and about 1.26% of capital costs. Third, while both models reveal that labor is not utilized efficiently, the dynamic model indicates a longer period of over-use and less variance over time in the degree of inefficiency. With the dynamic model, productivity growth is larger but more stable.

Asphalted Road Temperature Variations Due to Wind Turbine Cast Shadows

The contribution of this paper is a technique that in certain circumstances allows one to avoid the removal of dynamic shadows in the visible spectrum making use of images in the infrared spectrum. This technique emerged from a real problem concerning the autonomous navigation of a vehicle in a wind farm. In this environment, the dynamic shadows cast by the wind turbines' blades make it necessary to include a shadows removal stage in the preprocessing of the visible spectrum images in order to avoid the shadows being misclassified as obstacles. In the thermal images, dynamic shadows completely disappear, something that does not always occur in the visible spectrum, even when the preprocessing is executed. Thus, a fusion on thermal and visible bands is performed.

Photovoltaic field emulation including dynamic and partial shadow conditions

In this paper the development of a new laboratory prototype for the emulation of a photovoltaic (PV) field is presented. The proposed system is based on a DC/DC step-down converter topology and allows to obtain the solar array I– V curves, taking into account the environmental changes in solar irradiance and cell temperature. The DC/DC converter control strategy is deduced by using a comprehensive mathematical model of the PV field whose parameters are obtained from the knowledge of: (a) maximum power point data, measured when the PV plant power converter is running, (b) open circuit voltage and short-circuit current, measured off-line. This approach allows the most accurate representation of the PV source. Computer simulations and experimental results demonstrate that the proposed circuit acts as a highly accurate and efficient laboratory simulator of the photovoltaic array electrical characteristics both in steady state and transient conditions. Partial shading and fluctuating conditions can be reproduced too. Moreover the dynamic behaviour of the proposed laboratory emulator is suitable to its effective connection to power electronic interface to the utility or to load through a DC/DC boost converter.

A new approach for construction and rendering of dynamic light shaft

Due to high computational expense of simulating the physical model of atmospheric effect, rendering realistic natural light phenomena in real time is a challenging work. In this paper, we present a new approach for dynamic light shaft construction and rendering. Unified volumes construction is proposed for both dynamic light shaft and shadow, which is embedded into an efficient method of rendering natural light shafts with atmospheric scattering. We present the analytic formula of scattering computation without numerical integration and its implementation on current GPU. Our approach can simulate not only the lighting effect with single light source but also multiple parallel light sources according to the physical model of skylight and sunlight.