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Feature extraction of hyperspectral images for detecting immature green citrus fruit

Yongjun DING, Won Suk LEE, Minzan LI

《农业科学与工程前沿（英文）》 2018年 第5卷 第4期   页码 475-484 doi: 10.15302/J-FASE-2018241

摘要：

At an early immature growth stage of citrus, a hyperspectral camera of 369–1042 nm was employed to acquire 30 hyperspectral images in order to detect immature green fruit within citrus trees under natural illumination conditions. First, successive projections algorithm (SPA) were implemented to select 677, 804, 563, 962, and 405 nm wavebands and to construct multispectral images from the original hyperspectral images for further processing. Then, histogram threshold segmentation using NDVI of 804 and 677 nm was implemented to remove image backgrounds. Three slope parameters, calculated from the pairs 405 and 563 nm, 563 and 677 nm, and 804 and 962 nm were used to construct a classifier to identify the potential citrus fruit. Then, a marker-controlled watershed segmentation based on wavelet transform was applied to obtain potential fruit areas. Finally, a green fruit detection model was constructed according to Grey Level Co-occurrence Matrix (GLCM) texture features of the independent areas. Three supervised classifiers, logistic regression, random forest and support vector machine (SVM) were developed using texture features. The detection accuracies were 79%, 75%, and 86% for the logistic regression, random forest, and SVM models, respectively. The developed algorithm showed a great potential for identifying immature green citrus for an early yield estimation.

关键词： hyperspectral     green citrus     image processing     fruit detection     precision agriculture     yield mapping    

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Chemical mapping of cement pastes by using confocal Raman spectroscopy

Fengjuan LIU,Zhihui SUN

《结构与土木工程前沿（英文）》 2016年 第10卷 第2期   页码 168-173 doi: 10.1007/s11709-015-0323-9

摘要： In the present study, chemical mapping on the hydration process of cement paste with water-to-cement ( / ) ratio of 0.60 was implemented by Raman spectroscopy (RS). The RS was applied to study the paste from 12 hours after mixing to 28 days. Cement ingredients and hydration products, including calcium silicates (C S and C S), calcium hydroxide (CH), and ettringite, were quantitatively studied. From the research, it is observed that calcium silicates were consumed gradually with the increased hydration age. Calcium hydroxide increased and tended to cluster in the pore vicinity during hydration. Ettringite was found to form on the surface of the unreacted particles, which was shown as a mixed zone of ettringite and calcium silicates in the maps. It is concluded from the study that chemical mapping was an effective method to assist in visualizing particle dispersion and connection on top of the quantitative analysis.

关键词： chemical mapping     Raman spectroscopy     calcium silicates     calcium hydroxide     ettringite    

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Independent continuous and mapping method of structural topology optimization based on the global stress

Yunkang SUI, Jili FENG, Hongling YE, Xirong PENG,

《机械工程前沿（英文）》 2010年 第5卷 第2期   页码 130-142 doi: 10.1007/s11465-010-0011-3

摘要： There are three difficulties in topology optimization of continuum structures. 1) The topology under multiple load case is more difficult to be optimized than under single load case, because the former becomes a multiple objective based on compliance objective functions. 2) With local constraints, such as an elemental stress limit, the topology is more difficult to be solved than with global constraints, such as the displacement or frequency limits, because the sensitivity analysis of the former has very expensive computation. 3) With the phenomenon of load illness, which is similar with stiffness illness in the structural analysis, it is not easy to get the reasonable final topological structure, because it is difficult to consider different influences between the loads with small forces and big forces, and some topology paths of transferring small forces may disappear during the iteration process. To overcome difficulties above, four measures are adopted. 1) Topology optimization model is established by independent continuous mapping (ICM) method. 2) Based on the von Mises strength theory, all elements’ stress constraints are transformed into a structural energy constraint. 3) The phenomenon of load illness is divided to classify into three cases. 4) A strategy based on strain energy is proposed to adopt ICM method with stress globalization, and the problems of the above mentioned three cases of load illness are solved in terms of different complementary approaches. Several numerical examples show that the topology path of transferring forces can be obtained more easily by substituting global strain energy constraints for local stresses constraints, and the problem of load illness can be solved well by the weighting method that takes the structural energy as a weighting coefficient.

关键词： independent continuous mapping (ICM) method     global stresses constraints     topology optimization     continuum structure     load illness    

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PLANT DENSITY, IRRIGATION AND NITROGEN MANAGEMENT: THREE MAJOR PRACTICES IN CLOSING YIELD GAPS FOR AGRICULTURAL

《农业科学与工程前沿（英文）》 2021年 第8卷 第4期 doi: 10.15302/J-FASE -2020355

摘要：

Agriculture faces the dual challenges of food security and environmental sustainability. Here, we investigate current maize production at the field scale, analyze the yield gaps and impacting factors, and recommend measures for sustainably closing yield gaps. An experiment was conducted on a 3.9-ha maize seed production field in arid north-western China, managed with border and drip irrigation, respectively, in 2015 and 2016. The relative yield reached 70% in both years. However, drip irrigation saved 227 mm irrigation water during a drier growing season compared with traditional border irrigation, accounting for 44% of the maize evapotranspiration (ET). Yield variability under drip irrigation was 12.1%, lower than the 18.8% under border irrigation. Boundary line analysis indicates that a relative yield increase of 8% to 10% might be obtained by optimizing the yield-limiting factors. Plant density and soil available water content and available nitrogen were the three major factors involved. In conclusion, closing yield gaps with agricultural sustainability may be realized by optimizing agronomic, irrigation and fertilizer management, using water-saving irrigation methods and using site-specific management.

 

关键词： boundary line analysis     irrigation method     precision agriculture     spatial variability     yield gaps     yield-limiting factors    

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A survey of photon mapping state-of-the-art research and future challenges

Chun-meng KANG,Lu WAN,Yan-ning XU,Xiang-xu MENG

《信息与电子工程前沿（英文）》 2016年 第17卷 第3期   页码 185-199 doi: 10.1631/FITEE.1500251

摘要： Global illumination is the core part of photo-realistic rendering. The photon mapping algorithm is an effective method for computing global illumination with its obvious advantage of caustic and color bleeding rendering. It is an active research field that has been developed over the past two decades. The deficiency of precise details and efficient rendering are still the main challenges of photon mapping. This report reviews recent work and classifies it into a set of categories including radiance estimation, photon relaxation, photon tracing, progressive photon mapping, and parallel methods. The goals of our report are giving readers an overall introduction to photon mapping and motivating further research to address the limitations of existing methods.

关键词： Global illumination     Photon mapping     Radiance estimation     Photon relaxation     Progressive photon mapping    

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and future research directions for the phytoremediation of heavy metal-contaminated soil: A knowledge mapping

《环境科学与工程前沿（英文）》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1507-2

摘要：

• The overall global perspective of the PHMCS field was obtained.

关键词： Heavy metal-contaminated soil     Hot topics     Knowledge mapping analysis     Knowledge base     Phytoremediation    

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The effect of conservation tillage on crop yield in China

Hongwen LI,Jin HE,Huanwen GAO,Ying CHEN,Zhiqiang ZHANG

《农业科学与工程前沿（英文）》 2015年 第2卷 第2期   页码 179-185 doi: 10.15302/J-FASE-2015058

摘要： Traditional agricultural practices have resulted in decreased soil fertility, shortage of water resources and deterioration of agricultural ecological environment, which are seriously affecting grain production. Conservation tillage (CT) research has been developed and applied in China since the 1960s and 1970s, and a series of development policies have been issued by the Chinese government. Recent research and application have shown that CT has positive effects on crop yields in China. According to the data from the Conservation Tillage Research Center (CTRC), Chinese Ministry of Agriculture (MOA), the mean crop yield increase can be at least 4% in double cropping systems in the North China Plain and 6% in single cropping systems in the dryland areas of North-east and North-west China. Crop yield increase was particularly significant in dryland areas and drought years. The mechanism for the yield increase in CT system can be attributed to enhanced soil water content and improved soil properties. Development strategies have been implemented to accelerate the adoption of CT in China.

关键词： conservation tillage     crop yield     soil structure     development strategies    

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Breeding strategies for increasing yield potential in super hybrid rice

Shihua CHENG,Xiaodeng ZHAN,Liyong CAO

《农业科学与工程前沿（英文）》 2015年 第2卷 第4期   页码 277-282 doi: 10.15302/J-FASE-2015081

摘要： Super hybrid rice breeding is a new breeding method combining semi-dwarf breeding and heterosis breeding using germplasm and gene-environment interactions. This paper reviews the breeding strategies of super hybrid rice breeding in China, focusing on the utilization of heterosis of indica and japonica subspecies, construction of ideal plant architecture and pyramiding of disease resistant genes in restorer lines. To develop super hybrid rice, considerable effort should be made to explore genes related with high yield, good quality, resistance to pests and diseases, tolerance to stresses. Molecular breeding methods in combination with crossing techniques should be adopted in super hybrid rice breeding.

关键词： super hybrid rice     breeding strategies     yield potential    

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Highlight yield forming and innovative technologies in tropical crops

Wenquan WANG

《农业科学与工程前沿（英文）》 2016年 第3卷 第4期   页码 283-284 doi: 10.15302/J-FASE-2016128

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Electromagnetic induction mapping at varied soil moisture reveals field-scale soil textural patterns

Hiruy ABDU, David A. ROBINSON, Janis BOETTINGER, Scott B. JONES

《农业科学与工程前沿（英文）》 2017年 第4卷 第2期   页码 135-145 doi: 10.15302/J-FASE-2017143

摘要： Knowledge of the spatial distribution of soil textural properties is important for determining soil moisture storage and soil hydraulic transport properties. Capturing field heterogeneity without exhaustive sampling and costly sample analysis is difficult. Our objective was to employ electromagnetic induction (EMI) mapping in low apparent electrical conductivity (EC ) soils at varying soil water contents to capture time invariant properties such as soil texture. Georeferenced EC measurements were taken using a ground conductivity meter on six different days where volumetric water content ( ) varied from 0.11 to 0.23. The 50 m × 50 m field included a subsurface gravelly patch in an otherwise homogeneous silt-loam alluvial soil. Ordinary block kriging predicted EC at unsampled areas to produce 1-m resolution maps. Temporal stability analysis was used to divide the field into three distinct EC regions. Subsequent ground-truthing confirmed the lowest conductivity region correlated with coarse textured soil parent materials associated with a former high-energy alluvial depositional area. Combining maps using temporal stability analysis gives the clearest image of the textural difference. These maps could be informative for modeling, experimental design, sensor placement and targeted zone management strategies in soil science, ecology, hydrology, and agricultural applications.

关键词： soil electrical conductivity     soil texture mapping     temporal stability analysis    

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YIELD AND FRUIT QUALITY OF ALMOND, PEACH AND PLUM UNDER REGULATED DEFICIT IRRIGATION

《农业科学与工程前沿（英文）》 2021年 第8卷 第4期   页码 583-593 doi: 10.15302/J-FASE -2020325

摘要：

The effects of regulated deficit irrigation (RDI) on the performance of almond cv. Tuono, peach cv. JH-Hall and plum cv. Stanley were assessed on the Saiss Plain (NW, Morocco) over three consecutive growing seasons (2011–2013). Irrigation treatments consisted of a control, irrigation applied to fully satisfy crop water requirements (100% ETC), and two RDI treatments, irrigation applied to 75% ETC (RDI-75) and 50% ETC (RDI-50). These three treatments were applied during fruit-growth slowdown periods corresponding to Stages II and III in almond and Stage II in peach and plum. Yield and fruit quality traits were determined. The effect of RDI differed between species. Yield and fruit size were reduced significantly only in peach under RDI-50. Fruit quality improved in this species in the first year of the experiment, with an increase of sugar/acid ratio and polyphenol content. Plum quality also improved but the effects were significant only in the second and third years. Similar results were recorded in almond kernel, but their epidermal grooves were deeper under RDI-50, and this may have affected their commercial value. It is concluded that water can be saved during the fruit-growth slowdown period by up to 25% in peach and 50% in almond and plum with improvements in fruit quality without affecting total yield.

 

关键词： fruit quality / fruit yield / Prunus domestica / Prunus dulcis / Prunus persica / regulated deficit irrigation    

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Estimating the effect of urease inhibitor on rice yield based on NDVI at key growth stages

Kailou LIU,Yazhen LI,Huiwen HU

《农业科学与工程前沿（英文）》 2014年 第1卷 第2期   页码 150-157 doi: 10.15302/J-FASE-2014028

摘要： The effect of the urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT) at a range of application rates on rice production was examined in a field experiment at Jinxian County, Jiangxi Province, China. The normalized difference vegetation index (NDVI) was measured at key growth stages in both early and late rice. The results showed that the grain yield increased significantly when urea was applied with NBPT, with the highest yield observed at 1.00% NBPT (wt/wt). NDVI differed with the growth stage of rice; it remained steady from the heading to the filling stage. Rice yield could be predicted from the NDVI taken at key rice growing stages, with ranging from 0.34 to 0.69 in early rice and 0.49 to 0.70 in late rice. The validation test showed that RMSE (t·hm ) values were 0.77 and 0.87 in early and late rice, respectively. Therefore, it was feasible to estimate rice yield for different amounts of urease inhibitor using NDVI.

关键词： normalized difference vegetation index (NDVI)     N-(n-butyl) thiophosphoric triamide (NBPT)     rice     grain yield    

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Lodging resistance and yield potential of winter wheat: effect of planting density and genotype

Yonggui XIAO,Jianjun LIU,Haosheng LI,Xinyou CAO,Xianchun XIA,Zhonghu HE

《农业科学与工程前沿（英文）》 2015年 第2卷 第2期   页码 168-178 doi: 10.15302/J-FASE-2015061

摘要： Improved lodging resistance is important for achieving high yield in irrigated environments. This study was conducted to determine genotypic variation in lodging resistance and related morphological traits among winter wheat cultivars planted at two densities, and to identify key traits associated with lodging resistance. Lodging performance of 28 genotypes, including 24 released cultivars and four advanced lines, was evaluated at 250 plants per square meter and 500 plants per square meter in Shandong province during the 2008–2009 and 2009–2010 crop seasons. At the higher density, the average grain yield was 2.6% higher, even though lodging score rose by as much as 136%. The higher planting density increased lodging through increased leaf area index (LAI), plant height, center of gravity and length of basal internodes, and reduced grain weight per spike and diameter of the lower two stem internodes. LAI, center of gravity and diameter of first internodes, as the important indicators for lodging resistance, were significantly correlated with lodging score, with = 0.62, 0.59 and −0.52 ( <0.01), respectively. Plant pushing resistance was significantly associated with diameter and length of the first internodes ( = 0.71–0.77, <0.01), indicating it could be used to assess the strength of the lower stem. Higher planting density could be used to select genotypes with lodging resistance in irrigated environments. Cultivars carrying high plant density tolerance and high yield potential, such as Jimai 22 and Liangxing 66, were recommended as leading cultivars for production as well as elite crossing parents for further increasing yield potential in the Yellow and Huai Valleys Winter Wheat Zone in China.

关键词： common wheat     yield potential     lodging performance     pushing resistance     leaf area index    

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Relationship between the number of tapping-induced secondary laticifer lines and rubber yield among

Yueyi CHEN,Xinsheng GAO,Xiaofei ZHANG,Weimin TIAN

《农业科学与工程前沿（英文）》 2016年 第3卷 第4期   页码 363-367 doi: 10.15302/J-FASE-2016122

摘要： The lack of suitable early selection parameters means that traditional rubber breeding for yield is time-consuming and inefficient. Laticifer is a tissue specific for natural rubber biosynthesis and storage in rubber tree. The number of the secondary laticifers in the trunk bark tissues is positively correlated with rubber yield in the matured rubber trees that are regularly tapped. In the present study, the rubber yield from 280 of 4–5 year-old virgin trees from 7 cross combinations was compared with the number of newly differentiated secondary laticifers caused by tapping. Results showed that the number of tapping-induced lines of secondary laticifers varied in different germplasm and was positively related to the rubber yield, indicating this could be used as a suitable parameter for early evaluation of yield potential of rubber trees.

关键词： Hevea brasiliensis     rubber yield breeding     early evaluation     tapping     secondary laticifer differentiation    

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Quantifying and mapping spatial variability of Shanghai household carbon footprints

Shangguang YANG,Chunlan WANG,Kevin LO,Mark WANG,Lin LIU

《能源前沿（英文）》 2015年 第9卷 第1期   页码 115-124 doi: 10.1007/s11708-015-0348-8

摘要： Understanding the spatial variability of household carbon emissions is necessary for formulating sustainable and low-carbon energy policy. However, data on household carbon emissions is limited in China, the world’s largest greenhouse gases emitter. This study quantifies and maps household carbon emissions in Shanghai using a city-wide household survey. The findings reveal substantial spatial variability in household carbon emissions, especially in transport-related emissions. Low emission clusters are founded in Hongkou, Xuhui, Luwan, Jinshan, and Fengxian. High emission clusters are located in Jiading and Pudong. Overall, the spatial pattern of household carbon emissions in Shanghai is donut-shaped: lowest in the urban core, increasing in the surrounding suburban areas, and declining again in the urban fringe and rural regions. The household emissions are correlated with a number of housing and socioeconomic factors, including car ownership, type of dwelling, size of dwelling, age of dwelling, and income. The findings underscore the importance of a localized approach to low-carbon policy-making and implementation.

关键词： household carbon emissions     spatial variability     energy policy     Shanghai     China    

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标题 作者 时间 类型 操作

Feature extraction of hyperspectral images for detecting immature green citrus fruit

Yongjun DING, Won Suk LEE, Minzan LI

期刊论文

Chemical mapping of cement pastes by using confocal Raman spectroscopy

Fengjuan LIU,Zhihui SUN

期刊论文

Independent continuous and mapping method of structural topology optimization based on the global stress

Yunkang SUI, Jili FENG, Hongling YE, Xirong PENG,

期刊论文

PLANT DENSITY, IRRIGATION AND NITROGEN MANAGEMENT: THREE MAJOR PRACTICES IN CLOSING YIELD GAPS FOR AGRICULTURAL

期刊论文

A survey of photon mapping state-of-the-art research and future challenges

Chun-meng KANG,Lu WAN,Yan-ning XU,Xiang-xu MENG

期刊论文

and future research directions for the phytoremediation of heavy metal-contaminated soil: A knowledge mapping

期刊论文

The effect of conservation tillage on crop yield in China

Hongwen LI,Jin HE,Huanwen GAO,Ying CHEN,Zhiqiang ZHANG

期刊论文

Breeding strategies for increasing yield potential in super hybrid rice

Shihua CHENG,Xiaodeng ZHAN,Liyong CAO

期刊论文

Highlight yield forming and innovative technologies in tropical crops

Wenquan WANG

期刊论文

Electromagnetic induction mapping at varied soil moisture reveals field-scale soil textural patterns

Hiruy ABDU, David A. ROBINSON, Janis BOETTINGER, Scott B. JONES

期刊论文

YIELD AND FRUIT QUALITY OF ALMOND, PEACH AND PLUM UNDER REGULATED DEFICIT IRRIGATION

期刊论文

Estimating the effect of urease inhibitor on rice yield based on NDVI at key growth stages

Kailou LIU,Yazhen LI,Huiwen HU

期刊论文

Lodging resistance and yield potential of winter wheat: effect of planting density and genotype

Yonggui XIAO,Jianjun LIU,Haosheng LI,Xinyou CAO,Xianchun XIA,Zhonghu HE

期刊论文

Relationship between the number of tapping-induced secondary laticifer lines and rubber yield among

Yueyi CHEN,Xinsheng GAO,Xiaofei ZHANG,Weimin TIAN

期刊论文

Quantifying and mapping spatial variability of Shanghai household carbon footprints

Shangguang YANG,Chunlan WANG,Kevin LO,Mark WANG,Lin LIU

期刊论文