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Article ; Online: Accurate Extraction of Cableways Based on the LS-PCA Combination Analysis Method

Wenxin Wang / Changming Zhao / Haiyang Zhang

Applied Sciences, Vol 13, Iss 2875, p

2023 Volume 2875

Abstract: In order to maintain a ski resort efficiently, regular inspections of the cableways are essential. However, there are some difficulties in discovering and observing the cable car cableways in the ski resort. This paper proposes a high-precision ... ...

Abstract	In order to maintain a ski resort efficiently, regular inspections of the cableways are essential. However, there are some difficulties in discovering and observing the cable car cableways in the ski resort. This paper proposes a high-precision segmentation and extraction method based on the 3D laser point cloud data collected by airborne lidar to address these problems. In this method, first, an elevation filtering algorithm is used to remove ground points and low-height vegetation, followed by preliminary segmentation of the cableway using the spatial distribution characteristics of the point cloud. The ropeway segmentation and extraction are then completed using the least squares-principal component combination analysis method for parameter fitting. Additionally, we selected three samples of data from the National Alpine Ski Center to be used as test objects. The real value is determined by the number of point clouds manually deducted by CloudCompare. The extraction accuracy is defined as the ratio of the number of point clouds extracted by the algorithm to the number of point clouds manually extracted. While the environmental complexities of the samples differ, the algorithm proposed in this paper is capable of segmenting and extracting cableways with great accuracy, achieving a comprehensive and effective extraction accuracy rate of 90.59%, which is sufficient to meet the project’s requirements.
Keywords	ropeway of cable car ; adaptation ; segmentation and extraction ; spatial distribution characteristics ; least squares-principal component analysis ; extraction accuracy ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	518
Language	English
Publishing date	2023-02-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Research on the Calculation and Analysis of Ski-Track Areas Based on Laser Point Clouds

Wenxin Wang / Changming Zhao / Haiyang Zhang

Applied Sciences, Vol 13, Iss 1632, p

2023 Volume 1632

Abstract: To address the long-term statistical problem of ski-track area in the construction and operation of ski resorts, we propose a new ski-track point cloud boundary extraction method that improves the accuracy of boundary extraction and minimizes the offset ... ...

Abstract	To address the long-term statistical problem of ski-track area in the construction and operation of ski resorts, we propose a new ski-track point cloud boundary extraction method that improves the accuracy of boundary extraction and minimizes the offset of the area error. In this method, all point clouds are first projected onto the fitting plane using the random sample consensus (RANSAC) method. An improved point cloud boundary extraction algorithm is used to triangulate and extract the high-precision ski-track boundary. A discrete Green formula is then used to calculate and count the ski track’s exact area. It is demonstrated through five sets of test experiments that the error offset of the method proposed in this paper is smaller than that of other classical methods, which confirms its benefits and feasibility.
Keywords	laser point clouds ; ski-track area ; boundary extraction ; discrete Green formula ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	310
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Research on echo characteristics in remote detection with the pulse LiDAR of aerial targets under diverse atmospheric conditions

Si Chen / Haiyang Zhang / Fahong Jin / Lin Wang / Changming Zhao

Heliyon, Vol 9, Iss 6, Pp e16728- (2023)

2023

Abstract: This paper utilizes the idea of theoretical analysis to introduce a method for echo characteristics in remote detection with the pulse LiDAR of aerial targets under atmospheric conditions. A Missiles and an aircraft are selected as simulation targets. ... ...

Abstract	This paper utilizes the idea of theoretical analysis to introduce a method for echo characteristics in remote detection with the pulse LiDAR of aerial targets under atmospheric conditions. A Missiles and an aircraft are selected as simulation targets. The relation among mutual mapping of target surface elements can be directly gained by setting light source and target parameters. We discuss influences on atmospheric transport conditions, target shapes and detection conditions on echo characteristics. Atmospheric transport model is introduced as weather conditions, including sunny and cloudy days, with or without turbulence. Simulation results conclude that the outline of scanned waveform can invert the target shape. These provide a theoretical basis for improving the target detection and tracking performance.
Keywords	The pulse LiDAR ; Aerial targets ; Echo characteristics ; Atmospheric conditions ; Science (General) ; Q1-390 ; Social sciences (General) ; H1-99
Subject code	380
Language	English
Publishing date	2023-06-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: A New Method of Ski Tracks Extraction Based on Laser Intensity Information

Wenxin Wang / Changming Zhao / Haiyang Zhang

Applied Sciences, Vol 12, Iss 5678, p

2022 Volume 5678

Abstract: At present, the mainstream laser point cloud classification algorithms are mainly based on the geometric information of the target. Nevertheless, if there is occlusion between the targets, the classification effect will be negatively affected. Compared ... ...

Abstract	At present, the mainstream laser point cloud classification algorithms are mainly based on the geometric information of the target. Nevertheless, if there is occlusion between the targets, the classification effect will be negatively affected. Compared with the above methods, a new method of ski tracks extraction using laser intensity information based on target reflection is presented in this paper. The method can complete the downsampling of the point cloud datasets of ski tracks under the condition that the information of the target edge is complete. Then, the clustering and extraction of ski tracks are effectively accomplished based on the smoothing threshold and curvature between adjacent point clouds. The experimental results show that, different from the traditional methods, the composite classification method based on the intensity information proposed in this paper can effectively extract ski tracks from the complex background. By comparing the proposed method to the Euclidean distance method, the clustering segmentation method, and the RANSAC method, the average extraction accuracy is increased by 16.9%, while the over extraction rate is reduced by 8.4% and the under extraction rate is reduced by 8.6%, allowing us to accurately extract the ski track point cloud of a ski resort.
Keywords	classification algorithms ; smoothing threshold and curvature ; laser intensity information ; ski tracks ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	006
Language	English
Publishing date	2022-06-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Effects of Tree Species and Soil Enzyme Activities on Soil Nutrients in Dryland Plantations

Yage Li / Chun Han / Shan Sun / Changming Zhao

Forests, Vol 12, Iss 1153, p

2021 Volume 1153

Abstract: Long-term afforestation strongly changes the soil’s physicochemical and biological properties. However, the underlying mechanism of different tree species driving change in soil nutrients is still unclear in the long-term dryland plantations of the Loess ...

Abstract	Long-term afforestation strongly changes the soil’s physicochemical and biological properties. However, the underlying mechanism of different tree species driving change in soil nutrients is still unclear in the long-term dryland plantations of the Loess Plateau, China. In this study, samples of surface soil (0–20 cm) and woody litter were collected from five plantations (≥50 years) of Caragana korshinskii , Armeniaca sibirica , Populus hopeiensis , Platycladus orientalis , and Pinus tabulaeformis and a natural grassland, and tested for the carbon, nitrogen, phosphorus, and potassium contents, as well as the soil sucrase (SC), urease (UE), and alkaline phosphorus (ALP) activities. We found that soil nutrients, enzyme activities, and the litter’s chemical properties obviously varied among five tree species. C. korshinskii significantly increased the soil’s TC, organic carbon (OC), total nitrogen (TN), available nitrogen (AN), and available potassium (AK) by 28.42%, 56.08%, 57.41%, 107.25%, and 10.29%, respectively, and also increased the soil’s available phosphorus (AP) by 18.56%; while P. orientalis significantly decreased soil TN (38.89%), TP (30.58%), AP (76.39%), TK (8.25%), and AK (8.33%), and also decreased soil OC (18.01%) and AN (1.09%), compared with those in grassland. The C. korshinskii plantation had higher quality litter and soil enzyme activities than the P. orientalis plantation. Moreover, 62.2% of the total variation in soil nutrients was explained by the litter’s chemical properties and soil enzyme activities, and the litter phosphorus (LP) and soil ALP had a more significant and positive impact on soil nutrients. Therefore, tree species, LP, and soil ALP were key factors driving soil nutrient succession in dryland plantations. The significantly positive nitrogen–phosphorus coupling relationship in the “litter–enzyme–soil” system revealed that the improving nitrogen level promoted the phosphorus cycle of the plantation ecosystem. Our results suggest that leguminous tree species are more suitable for dryland afforestation through the regulation of litter quality and soil enzyme activities.
Keywords	drought response ; global warming ; leguminous tree species ; litter quality ; soil properties ; Plant ecology ; QK900-989
Language	English
Publishing date	2021-08-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Pinus tabulaeformis Forests Have Higher Carbon Sequestration Potential Than Larix principis-rupprechtii Forests in a Dryland Mountain Ecosystem, Northwest China

Chun Han / Yage Li / Xiaoxue Dong / Changming Zhao / Lizhe An

Forests, Vol 13, Iss 739, p

2022 Volume 739

Abstract: Carbon sinks in terrestrial ecosystems can be significantly increased by afforestation, which will slow global warming. However, it is still unclear how different plantations influence the carbon sink and how they respond to environmental factors, ... ...

Abstract	Carbon sinks in terrestrial ecosystems can be significantly increased by afforestation, which will slow global warming. However, it is still unclear how different plantations influence the carbon sink and how they respond to environmental factors, especially in drylands. In this study, eddy correlation method (EC) was used to measure carbon and water fluxes and environmental factors of two artificial forests ( Larix principis-rupprechtii and Pinus tabulaeformis ) in the dryland of Northwest China, and the responses of evapotranspiration (ET), net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (RECO) to environmental factors were also assessed. Results showed that the L. principis-rupprechtii forest ecosystem had higher water use efficiency (WUE), light use efficiency (LUE), GPP, and RECO than the P. tabulaeformis forest ecosystem. However, the proportion of net ecosystem production (NEP) to GPP in the P. tabulaeformis forest ecosystem (62.89%) was higher than that in the L. principis-rupprechtii forest ecosystem (47.49%), indicating that the P. tabulaeformis forest ecosystem had the higher carbon sequestration efficiency. In addition, the CO 2 and H 2 O fluxes in the L. principis-rupprechtii forest ecosystem were more sensitive to environmental factors, compared with the P. tabulaeformis forest ecosystem. Further, the RECO of the L. principis-rupprechtii forest ecosystem was more sensitive to temperature changes, which implies that the L. principis-rupprechtii forest ecosystem will release more CO 2 than the P. tabulaeformis forest ecosystem with a warming climate. Therefore, the P. tabulaeformis forest ecosystem may have better carbon sequestration potential. These results are important for understanding the effects of climate change on the CO 2 and H 2 O cycles in coniferous plantation ecosystems in drylands.
Keywords	eddy covariance ; carbon and water fluxes ; water use efficiency ; light use efficiency ; temperature sensitivity ; coniferous plantation ecosystems ; Plant ecology ; QK900-989
Language	English
Publishing date	2022-05-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
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Article ; Online: Effects of Rock Fragments on the Soil Physicochemical Properties and Vegetation on the Northeastern Tibetan Plateau

Ying Zheng / Ning Chen / Cankun Zhang / Xiaoxue Dong / Changming Zhao

Frontiers in Environmental Science, Vol

2021 Volume 9

Abstract: Stony soils are very widely distributed and contain abundant rock fragments (>2 mm), which impose major effects on soil properties and plant growth. However, the role of rock fragments is still often neglected, which can lead to an inadequate ... ...

Abstract	Stony soils are very widely distributed and contain abundant rock fragments (>2 mm), which impose major effects on soil properties and plant growth. However, the role of rock fragments is still often neglected, which can lead to an inadequate understanding of the interaction between plants and soil. Undisturbed soil columns were collected from three alpine grasslands on the Qilian Mountain, and the X-ray computed tomography method was applied to investigate the characteristics of rock fragments. The results showed there was significant difference in number density, volumetric content and surface area density of rock fragment among the three grasslands, and followed the order of alpine meadow > alpine steppe > alpine desert steppe. In addition, the soil organic carbon, total nitrogen, total phosphorus, available phosphorus, N-NH4+, and N-NO3− contents in fine earth all increased with increasing number density, volumetric content and surface area density but to different degrees. Furthermore, positive correlations were observed between the rock shape factor and belowground biomass (R2 = 0.531, p < 0.05), between the rock volumetric content and aboveground biomass (R2 = 0.527, p < 0.05), and between number density and Simpson’s index (R2 = 0.875, p < 0.05). Our findings suggest that within a certain range, the increase in rock fragment content is conducive to soil nutrient accumulation and soil water storage and circulation and changes plant features, which contributes to the growth of plants. In addition, rock fragments should be given more consideration when investigating the relationships between soil and vegetation and their response to climate change in future studies.
Keywords	stony soil ; rock fragments ; X-ray CT ; tibetan plateau ; alpine grassland ; Environmental sciences ; GE1-350
Subject code	550
Language	English
Publishing date	2021-06-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
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Article ; Online: Spatial pattern variation of artificial sand-binding vegetation based on UAV imagery and its influencing factors in an oasis–desert transitional zone

Ying Zheng / Qiyue Yang / Heng Ren / Dejin Wang / Changming Zhao / Wenzhi Zhao

Ecological Indicators, Vol 141, Iss , Pp 109068- (2022)

2022

Abstract: The spatial pattern of vegetation can reflect the impacts of the environment on plants and the response of plants to the environment, which can promote a deep understanding of the potential driving mechanisms of vegetation evolution and community ... ...

Abstract	The spatial pattern of vegetation can reflect the impacts of the environment on plants and the response of plants to the environment, which can promote a deep understanding of the potential driving mechanisms of vegetation evolution and community maintenance. A sand-binding vegetation system without irrigation has been implemented in the oasis–desert transitional zone since the 1970 s, where the annual precipitation has been approximately 120 mm. While the mobile dunes have been effectively stabilized, a patchy pattern of sand-binding vegetation has been observed. However, we do not understand why the pattern of sand-binding vegetation changed from the initial uniform distribution to the current patchy pattern. In this study, low-altitude UAV remote sensing technology and imaging-based quantification techniques were used to explore the effects of biotic and abiotic factors on the spatial patterns of sand-binding vegetation over 50 years. The spatial pattern of Haloxylon ammodendron changed gradually from a uniform distribution to an aggregated distribution, and the degree of patch fragmentation of H. ammodendron at the landscape scale gradually increased with the age of the sand-binding vegetation. The artificial sand-binding vegetation composed of H. ammodendron showed discontinuous change in which the system state reached a transition point after 30 years and changed to another state after 40 years. There were no significant correlations between the landscape indices and soil water content in the shallow layers (0–10 cm, 10–50 cm), while the soil water content in the 50–100 cm layers was significantly negatively correlated with the class area, percentage of landscape, largest patch index, percentage of like adjacencies and aggregation index and was positively correlated with the normalized landscape shape index. The soil water content in the 100–200 cm layers was positively correlated with the number of patches and patch density. Competition intensity at the individual level had a more significant effect on ...
Keywords	Oasis–desert transitional zone ; Artificial sand-binding vegetation ; Spatial pattern variation ; Landscape indices ; UAV imagery ; Ecology ; QH540-549.5
Subject code	910 ; 580
Language	English
Publishing date	2022-08-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
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Article ; Online: Camera Trapping Reveals Spatiotemporal Partitioning Patterns and Conservation Implications for Two Sympatric Pheasant Species in the Qilian Mountains, Northwestern China

Dexi Zhang / Bei An / Liuyang Chen / Zhangyun Sun / Ruirui Mao / Changming Zhao / Lixun Zhang

Animals, Vol 12, Iss 1657, p

2022 Volume 1657

Abstract: Studying the spatio-temporal niche partitioning among closely related sympatric species is essential for understanding their stable coexistence in animal communities. However, consideration of niche partitioning across multiple ecological dimensions is ... ...

Abstract	Studying the spatio-temporal niche partitioning among closely related sympatric species is essential for understanding their stable coexistence in animal communities. However, consideration of niche partitioning across multiple ecological dimensions is still poor for many sympatric pheasant species. Here, we studied temporal activity patterns and spatial distributions of the Blue Eared Pheasant (EP, Crossoptilon auritum ) and Blood Pheasant (BP, Ithaginis cruentus ) in the Qilian Mountains National Nature Reserve (QMNNR), Northwestern China, using 137 camera traps from August 2017 to August 2020. Kernel density estimation was applied to analyze diel activity patterns, and the Maxent model was applied to evaluate their suitable distributions and underlying habitat preferences. Eight Galliformes species were captured in 678 detection records with 485 records of EP and 106 records of BP over a total of 39,206 camera days. Their monthly activity frequencies demonstrate temporal partitioning but their diel activity patterns do not. Furthermore, 90.78% of BP distribution (2867.99 km 2 ) overlaps with the distribution of EP (4355.86 km 2 ) in the QMNNR. However, BP manifests a high dependence on forest habitats and shows larger Normalized Difference Vegetation Index (NDVI) values, while EP showed obvious avoidance of forest with NDVI greater than 0.75. Hence, differentiation in monthly activity patterns and partitioning in habitat preference might facilitate their coexistence in spatiotemporal dimensions. Conservation actions should give priority to highly overlapping areas in the center and east of the QMNNR and should strengthen forest landscape connectivity, as they provide irreplaceable habitats for these threatened and endemic Galliformes.
Keywords	Crossoptilon auritum ; Ithaginis cruentus ; galliformes ; activity pattern ; species distribution model (SDM) ; habitat overlap ; Veterinary medicine ; SF600-1100 ; Zoology ; QL1-991
Subject code	333
Language	English
Publishing date	2022-06-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: C, N, P, K stoichiometric characteristics of the “leaf-root-litter-soil” system in dryland plantations

Yage Li / Xiaoxue Dong / Wenxiu Yao / Chun Han / Shan Sun / Changming Zhao

Ecological Indicators, Vol 143, Iss , Pp 109371- (2022)

2022

Abstract: Plantation’s nutrient cycling can regulate and affect the material cycling of ecosystems, which is the key to maintain the sustainable development of the plantation ecosystem. However, the current understanding of the nutrient cycling characteristics of ... ...

Abstract	Plantation’s nutrient cycling can regulate and affect the material cycling of ecosystems, which is the key to maintain the sustainable development of the plantation ecosystem. However, the current understanding of the nutrient cycling characteristics of the “leave-root-litter-soil” continuum of dryland plantation ecosystems is limited. Therefore, in the Longzhong Loess Plateau of China, we selected nine typical dryland plantations to carry related research, including two evergreen (Platycladus orientalis (13-years and 50-years) and Pinus tabuliformis) and four deciduous (Caragana korshinskii (13-years, 35-years and 55-years), Armeniaca sibirica, Populus hopeiensis and Tamarix chinensis) tree species, and measured C, N, P and K contents of green leaves, fine roots, leaf litter and surface soil (0–20 cm). Results showed tree species and afforestation years strongly changed C, N, P and K contents and ratios of green leaves, fine roots, leaf litter and soil components, and also significantly affected leaf N, P and K reabsorption efficiencies. The average N, P and K contents of four components and soil available nitrogen (AN), available phosphorus (AP) and available potassium (AK) contents in deciduous plantations were higher than those in evergreen plantations, resulting in the lower C:N:P:K stoichiometry of deciduous plantations than evergreen plantations. Especially in 55-years C. korshinskii plantation, its soil C, N, AN, AP and AK contents were higher than those in A. sibirica, P. hopeiensis, P. orientalis and P. tabuliformis plantations. Moreover, soil C, N, P, AN, AP and AK contents in C. korshinskii plantations increased significantly with the increase of afforestation years. Thus, C. korshinskii was more suitable for ecological restoration in drylands. Due to the P limitation in plantations, P reabsorption efficiency was higher than N reabsorption efficiency, and significantly negatively correlated with P contents of four components. And green leaves had the homeostasis to soil AP, which may be the nutrient ...
Keywords	Ecological stoichiometry ; Nutrient reabsorption efficiency ; Homeostasis ; Nutrient limitation ; The Longzhong Loess Plateau ; Ecology ; QH540-549.5
Subject code	580
Language	English
Publishing date	2022-10-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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