Wyniki wyszukiwania - Biblioteka Nauki

1

A Duality between Forward and Adjoint MPI Communication Routines

100%

Cheng B.

Computational Methods in Science and Technology

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2006

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tom Vol. spec. issue

23-24

EN

In this article, we explore a natural duality that exist between MPI communication routines in parallel programs, and show the ease of its adjoint implementation via pointers.

2

Investigation of combined pollution between malathion and a variety of pollutants based on the fractional factorial design (resolution IV)

51%

Cheng B. , Li S. , Wang M. , Li Y.

Polish Journal of Environmental Studies

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2015

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tom 24

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nr 5

3

Object based segmentation of video using variational level sets

51%

Cheng B. , Wang Y. , Zheng N. , Bian Z.

Machine Graphics and Vision

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2005

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tom Vol. 14, No. 2

145-157

EN

The paper demonstrates a new approach to video segmentation which retains some of the attractive features of existing methods and overcomes some of their limitations. The video sequence is represented as a spatio-temporal volume, and is segmented by an extension of active contour model based on Mumford-Shah techniques. The energy function minimization is similar to 3D interface evolution with curvature-dependent speeds. The spatio-temporal volume need not to be smoothed before processing because our method is not sensitive to noise. Each object needs a closed interface, which is embedded as a level set of a higher-dimensional functions, and is propagated by solving a partial differential equation. The interface stops in the vicinity of object boundaries, which are not necessarily defined by the gradient and can be represented with complex topologies. Finally, an experiment is given to show the effectiveness and robustness of the method.

4

Partitioning of solar radiation in Arctic sea ice during melt season

51%

Lu P. , Cheng B. , Leppäranta M. , Li Z.

Oceanologia

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2018

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tom No. 60 (4)

464--477

EN

The partitioning of solar radiation in the Arctic sea ice during the melt season is investigated using a radiative transfer model containing three layers of melt pond, underlying sea ice, and ocean beneath ice. The wavelength distribution of the spectral solar irradiance clearly narrowed with increasing depth into ice, from 350-900 nm at the pond surface to 400-600 nm in the ocean beneath. In contrast, the net spectral irradiance is quite uniform. The absorbed solar energy is sensitive to both pond depth (Hp) and the underlying ice thickness (Hi). The solar energy absorbed by the melt pond (Ψp) is proportional only to Hp. However, the solar energy absorbed by the underlying ice (Ψi) is more complicated due to the counteracting effects arising from the pond and ice to the energy absorption. In September, Ψp decreased by 10% from its August value, which is attributed to more components in the shortwave band (<530 nm) of the incident solar radiation in September relative to August. The absorption coefficient of the sea ice only enhances the absorbed energy in ice, while an increase in the ice scattering coefficient only enhances the absorbed energy in the melt pond, although the resulted changes in Ψp and Ψi are smaller than that in the albedo and transmittance. The energy absorption rate with depth depends strongly on the incident irradiance and ice scattering, but only weakly on pond depth. Our results are comparable to previous field measurements and numerical simulations. We conclude that the incident solar energy was largely absorbed by the melt pond rather than by the underlying sea ice.

5

Interference adsorption of cadmium with a variety of pollutants in sediments based on fractional factorial design (resolution V)

51%

Gu W. , Cheng B. , Li Y.

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tom 26

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nr 1

EN

The characteristics of composite cadmium contamination via adsorption onto the surficial sediments in a pesticide (dimethoate, metalaxyl, atrazine, malathion, and prometryn)/heavy metal (copper, zinc, lead, cadmium, and nickel) composite contamination system were examined. To do this, a confounding designassisted resolution V of 2¹⁰⁻³ fractional factorial design method composed of a fixed effects model, a multiple linear regression model, and the best subset regression modeling methods was used to identify the main effects and second-order interaction effects of the aforementioned pollutants. Overall, 87.08% of the total contribution to cadmium adsorption derived from the main effect, and the main effects of copper, lead, zinc, and dimethoate had a significant antagonistic effect on cadmium adsorption on the sediments in the order of: copper (17.41%)>lead (13.09%)>zinc (10.06%)>dimethoate (5.03%), while the main effects of cadmium (41.49%) had a significant synergistic effect. Moreover, 12.92% of the total contribution to cadmium adsorption was attributed to second-order interaction effects (zinc*nickel and copper*zinc), with zinc*nickel (4.57%) having a significant antagonistic effect and copper*zinc (8.35%) having a significant synergistic effect on cadmium adsorption on the sediments. When compared with resolution IV of the 2¹⁰⁻⁵ fractional factorial design method, the freedom of resolution V of the 2¹⁰⁻³ fractional factorial design method increased from 21 to 45. This showed that resolution V of the 2¹⁰⁻³ fractional factorial design method can significantly distinguish the aliases of the second-order interaction effects related to the objective pollutant cadmium. Also, the total contribution to cadmium adsorption of the second-order interaction effects decreased from 61.48% to 12.92%, indicating that resolution IV of the 2¹⁰⁻⁵ fractional factorial design method overestimates the second-order interaction effect on cadmium adsorption on sediments.

6

3D plenoptic representation of a linear scene

51%

Cheng B. , Zheng N. , Quan W. , Li X.

Machine Graphics and Vision

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2001

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tom Vol. 10, No. 4

431-446

EN

This paper presents a novel 3D plenoptic function. We constrain camera motion to a line, and create a linear mosaic using a manifold mosaic. The plenoptic function is represented with three parameters: camera position along the axis, the angle between the ray and the centric axis, and the rotation angle in the vertical plane. Novel views are renderend by combining the appropriate captured rays in an efficient manner at the rendering time. Like panoramas, our method does not require recovery of geometric and photometric scene models. Moreover, it provides a much richer user experience by allowing the user to move freely in a linear region and observe significant parallax and lighting changes. Compared with either Lightfield or Lumigraph, it has a much smaller file size because a 3D only plenoptic function is constructed. Finally, an experiment with a synthetic environment is given to demonstrate its efficiency in capturing construction and rendering of a linear scene.

7

Partitioning of solar radiation in Arctic sea ice during melt season

51%

Lu P. , Cheng B. , Lepparanta M. , Li Z.

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tom 60

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nr 4

8

Reef Reservoir Identification by Wavelet Decomposition and Reconstruction : A Case Study from Yuanba Gas Field in China

51%

Cheng B. , Xu T. , Robbins B. , Shen Z. M.

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tom Vol. 63, no. 4

1025--1043

EN

The organic reef is a special type of carbonate reservoir which always dominates the spatial distribution, reserves and accumulations of natural gas. However, it is difficult to determine the organic reef’s internal structure and gas reservoirs due to numerous adverse factors such as the low resolution of seismic data, depth of burial, strong anisotropy, irregular spatial distribution and complex internal structure. A case study of wavelet decomposition and reconstruction technology applied to elucidate the features of organic reef reservoirs in the Changxing formation from Yuanba gas field shows that the seismic record reconstructed by high frequency signal can adequately describe the internal properties of organic reef reservoirs. Furthermore, the root mean square amplitude ratio of both low and high frequency data obtained from the reconstructed seismic data clearly show spatial distribution of gas and water in reef reservoirs.

9

Method of Structure Design and Heat Treatment of an Integrated Consolidation Sensor and Embedded Temperature Sensing Fabric

45%

Zhang R. , Deng N. , Cheng B. , Zhang R. , Wu Y.

Fibres & Textiles in Eastern Europe

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2016

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tom Vol. 24, no. 5 (119)

68--72

EN

In order to solve the problem of temperature sensors easily slipping and improve the precision of temperature measurement in temperature sensing fabric, a specially designed fabric was developed. In this paper, the fabric comprised plain and multi-layered fabric. Sensors were embedded into the multi-layered fabric. The multi-layered fabric was treated by partial heat treatment to make the temperature sensors be fixed to the fabric. The temperature sensing fabrics were measured before and after the partial heat treatment. The results showed that during the heat treatment, the number of fabric layers and fabric organization had an effect on temperature measurement, and the values measured after partial heat treatment were closer to the true value than without treatment. In addition, with an increase in the number of fabric layesr, the values measured were closer to the real value. And the measurement results were closer to the true value when the multi-layered fabric’s organizational structure was plain.

PL

Dla uzyskania hybrydowego elementu pomiarowego opracowano taką strukturę tkaniny aby móc umieścić w niej czujniki temperatury. Wielowarstwową tkaninę poddano odpowiedniej obróbce termicznej umożliwiającej zamocowanie czujników w tkaninie. Stwierdzono, że ilość warstw tkaniny i ich rozmieszczenie ma wyraźny wpływ na uzyskiwaną dokładność pomiaru temperatury. Przy zwiększeniu ilości warstw wzrastała dokładność pomiaru.

10

A study and application of high-resolution methods for reef reservoir identification

45%

Yan L. , Cheng B. , Xu T. , Wei S. , Qian Z.

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tom Vol. 65, no. 5

907--917

EN

Reefs represent a special type of carbonate trap that plays a key role in the migration, accumulation, and formation of a reservoir. They have commonly been the targets of exploration and development. However, reefs have complex interior structures and easily grow as thin, interbedded geological frames with reef microfacies that include the cap, core, and base of the reef. Because of the inherent drawbacks of seismic signals, including their low frequencies and narrow bandwidths, it is difficult to accurately identify reef reservoirs. Fortunately, the seismic frequency, phase, energy, waveform and other dynamic and geometrical properties can be used to compensate for the energy, expand the frequency bandwidth, and decompose and reconstruct the wavelet to obtain high-resolution seismic data. These data can highlight certain seismic responses of reefs, including boundary reflections, dome-shaped reflections from the reef outline, strong reflections from the reef cap, reflections from the reef bottom, and onlap reflections from the reef flanks. Some impedance response regularities, such as the lower impedance of the reef cap relative to the reef core and biodetritus beach and the fluctuating impedance of the reef-flat complex, are observed by combining log data with geological and high-resolution seismic data for a reef reservoir inversion. These methods were applied to the Changxing Formation in the Yuanba Gas Field. Good prediction results were obtained with a high consistency between the log and seismic data in a comparative analysis with the original seismic data and well logs.

11

Mathematical Model of Embedded Temperature Sensing Fabric Heat Transmission

45%

Zhang R. , Deng N. , Cheng B. , Zhang S. , Wu Y.

Fibres & Textiles in Eastern Europe

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2016

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tom Vol. 24, no. 5 (119)

73--79

EN

In order to explore effect factors in the measurement of temperature sensing fabric, a heat transmission mathematical model of temperature sensing fabric was established. The concept of surface contact thermal resistance associated with the material thermal conductivity, fabric layer number and yarn linear density between the fabric and sensor was proposed in the model, whose surface contact thermal resistance was produced in the process of fabric heat transmission. Some test samples were woven to prove the rationality of the model. The results demonstrated that the value measured would be influenced by the performances of surface contact thermal resistance, which was consistent with the derivation of the theoretical model. The raw material, fabric layer number and yarn linear density of temperature sensing fabric had a great effect on the measurement value. The correlation coefficient reached more than 0.988 among the experimental and theoretical values, respectively, which proved that the heat transmission mathematical model of temperature sensing fabric could be applied in the research of this fabric.

PL

Opracowano matematyczny model przepływu ciepła przez tkaninę zawierającą wbudowane czujniki temperatury w celu określenia wpływu poszczególnych czynników na przebieg pomiarów. Brano pod uwagę oporność termiczną styku czujników z tkaniną związaną z przewodnością termiczną materiału, ilość warstw i masę liniową przędz w obrębie tkaniny i czujników. Uzyskane współczynniki korelacji pomiędzy wartościami eksperymentalnymi i teoretycznymi przekraczały 0,988 co potwierdza, że opracowany przez nas matematyczny model przepływu ciepła w tkaninie pomiarowej można zastosować w tego typu badaniach.