为解决贫信息背景下对系统进行故障模式、影响及危害性分析(failure mode,effects and criticality analysis,FMECA)受故障信息少、故障数据部分未知等问题限制,同时为有限定量危害性矩阵分析方法的缺陷,提出了适用于贫信息背景的灰FMEC...为解决贫信息背景下对系统进行故障模式、影响及危害性分析(failure mode,effects and criticality analysis,FMECA)受故障信息少、故障数据部分未知等问题限制,同时为有限定量危害性矩阵分析方法的缺陷,提出了适用于贫信息背景的灰FMECA模型。首先对危害性矩阵图进行规范化改进,统一横纵坐标轴量纲,提出危害度权重比概念以规范作图比例;然后在危害度计算中引入区间灰数,提出矩域灰点概念以表征故障模式难以确知的危害性;最后依照不确定型决策思想给出矩域灰点的一般排序规则,为贫信息背景的故障模式危害性排序提供解决方案。通过某航天飞机主发动机高压燃料涡轮泵进行案例研究,验证了所提模型的有效性。展开更多
Knowledge and management of soil pH, particularly soil acidity across spatially variable soils is important, although this is greatly ignored by farmers. The objective of the study was to evaluate in-field spatial var...Knowledge and management of soil pH, particularly soil acidity across spatially variable soils is important, although this is greatly ignored by farmers. The objective of the study was to evaluate in-field spatial variability of soil pH, and compare the efficiency of managing soil pH through site-specific method vs. uniform lime application. The study was conducted on three sites with study sites I and II （23°50＇ S; 29°40＇ E）, and study sites IIl （23°59＇ S; 28°52＇ E） adjacent to each other in the semi-arid regions of the Limpopo Province, South Africa. Soil samples were taken in four replicates from geo-referenced locations on a regular grid of 30 m. Soils were analyzed for pH, and SMP buffer pH. Soil maps were produced with Geographic Information System （GIS） software, and soil pH datasets were interpolated using a geostatistical tool of inverse distance weighing （IDW）. Soil pH in the fields varied from 3.93 to 7.00. An excess amount of lime as high as 30 t/ha under uniform lime application were recorded. These recommendations were in excess on field areas that needed little or no lime applications. Again, there was an under applications of lime as much as 35 t/ha for uniform liming applications. This under- and over-recommendations of lime based on average soil pH values suggests that uniform soil acidity correction and soil pH management strategy is not an appropriate strategy to be adopted in these fields with spatially variable soils. The field can be divided into lime application zones of （1） high rates of lime, （2） low rates of lime and （3） areas that requires no lime at all so that lime rates are applied per zone. A key to site-specific soil acidity correction with lime is to reach ideal soil pH for the crop in all parts of the field.展开更多
Traditional information hiding algorithms cannot maintain a good balance of capacity,invisibility and robustness.In this paper,a novel blind colour image information hiding algorithm based on grey prediction and grey ...Traditional information hiding algorithms cannot maintain a good balance of capacity,invisibility and robustness.In this paper,a novel blind colour image information hiding algorithm based on grey prediction and grey relational analysis in the Discrete Cosine Transform(DCT) domain is proposed.First,this algorithm compresses the secret image losslessly based on the improved grey prediction GM(1,1)(IGM) model.It then chooses the blocks of rich texture in the cover image as the embedding regions using Double-dimension Grey Relational Analysis(DGRA).Finally,it adaptively embeds the compressed secret bits stream into the DCT domain mid-frequency coefficients,which are decided by those blocks' Double-Dimension Grey Correlation Degree(DGCD) and Human Visual System(HVS).This method can ensure an adequate balance between invisibility,capacity and robustness.Experimental results show that the proposed algorithm is robust against JPEG compression(46.724 6 dB when the compression quality factor is 90%),Gaussian noise(45.531 3 dB when the parameter is(0,0.000 5)) etc.,and it is a blind information hiding algorithm that can be extracted without an original carrier.展开更多
Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term...Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.展开更多
Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records cover...Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis .Results show that the rainfall in this area had a declining tendency in Spring at a rate of -21.2mm/10a, annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm, on the second place,with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm;and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.展开更多
92 soil samples were collected from granite, basalt and limestone areas of eastern China and determined for 13 trace element contents. The geographical tendencies of and factors affecting trace element contents in soi...92 soil samples were collected from granite, basalt and limestone areas of eastern China and determined for 13 trace element contents. The geographical tendencies of and factors affecting trace element contents in soils were studied.The sequences of soil trace element contents (especially the transitional elements in the 4th period) were: basalt soils > limestone soils > granite soils.The contents of trace elements in soils of granite areas and basalt areas showed great inheritance of trace element contents from the relevant parent rocks. The contents of trace elements in limestones were very low, but they became very high in limestone soils. Trace element contents of soils derived from limestone and basalt'increased significantly from north to south, these tendencies were similar to the tendency of ferric oxide contents in soils.There were differences of contents of trace elements bound to ferric oxide in different kinds of parent material and in different types of soil. The correlations between the contents of trace elements and the contents of ferric oxide were better in basalt soils than in granite soils.展开更多
Major and trace elements as well as strontium isotopic composition have been analyzed on the acid-insoluble (AI) phase of the loess-paleosol sequence from Luochuan, Shaanxi Province, China. Results show that the chemi...Major and trace elements as well as strontium isotopic composition have been analyzed on the acid-insoluble (AI) phase of the loess-paleosol sequence from Luochuan, Shaanxi Province, China. Results show that the chemical composition of AI phase of loess and paleosols is distinctive to the average composition of upper continental crust (UCC), characterized by depletion of mobile elements Na, Ca and Sr. The distribution pattern of elements in AI phase reveals that initial dust, derived from a vast area of Asian inland, has suffered from Na- and Ca-removed chemical weathering compared to UCC. Some geochemical parameters (such as CIA values, Na/K, Rb/Sr and87Sr/86Sr ratios) display a regular variation and evolution, reflecting that the chemical weathering in the source region of loess deposits has decreased gradually since 2.5 Ma with the general increase of global ice volume. This coincidence reflects that the aridity of Asian inland since the Quaternary is a possible regional response to the global climate change.展开更多
文摘为解决贫信息背景下对系统进行故障模式、影响及危害性分析(failure mode,effects and criticality analysis,FMECA)受故障信息少、故障数据部分未知等问题限制,同时为有限定量危害性矩阵分析方法的缺陷,提出了适用于贫信息背景的灰FMECA模型。首先对危害性矩阵图进行规范化改进,统一横纵坐标轴量纲,提出危害度权重比概念以规范作图比例;然后在危害度计算中引入区间灰数,提出矩域灰点概念以表征故障模式难以确知的危害性;最后依照不确定型决策思想给出矩域灰点的一般排序规则,为贫信息背景的故障模式危害性排序提供解决方案。通过某航天飞机主发动机高压燃料涡轮泵进行案例研究,验证了所提模型的有效性。
文摘Knowledge and management of soil pH, particularly soil acidity across spatially variable soils is important, although this is greatly ignored by farmers. The objective of the study was to evaluate in-field spatial variability of soil pH, and compare the efficiency of managing soil pH through site-specific method vs. uniform lime application. The study was conducted on three sites with study sites I and II （23°50＇ S; 29°40＇ E）, and study sites IIl （23°59＇ S; 28°52＇ E） adjacent to each other in the semi-arid regions of the Limpopo Province, South Africa. Soil samples were taken in four replicates from geo-referenced locations on a regular grid of 30 m. Soils were analyzed for pH, and SMP buffer pH. Soil maps were produced with Geographic Information System （GIS） software, and soil pH datasets were interpolated using a geostatistical tool of inverse distance weighing （IDW）. Soil pH in the fields varied from 3.93 to 7.00. An excess amount of lime as high as 30 t/ha under uniform lime application were recorded. These recommendations were in excess on field areas that needed little or no lime applications. Again, there was an under applications of lime as much as 35 t/ha for uniform liming applications. This under- and over-recommendations of lime based on average soil pH values suggests that uniform soil acidity correction and soil pH management strategy is not an appropriate strategy to be adopted in these fields with spatially variable soils. The field can be divided into lime application zones of （1） high rates of lime, （2） low rates of lime and （3） areas that requires no lime at all so that lime rates are applied per zone. A key to site-specific soil acidity correction with lime is to reach ideal soil pH for the crop in all parts of the field.
基金sponsored by the National Natural Science Foundation of China under Grants No.61170065,No.61003039,No.61202355the Science and Technology Support Project of Jiangsu under Grant No.BE2012183+4 种基金the Natural Science Key Fund for Colleges and Universities in Jiangsu Province under Grant No.12KJA520002the Postdoctoral Fund under Grants No.1101011B,No.2012M511753the Fund for Nanjing University of Posts and Telecommunications under Grant No.NY212047Fund of Jiangsu Computer Information Processing Technology Key Laboratory under Grant No.KJS1022the Priority Academic Program Development of Jiangsu Higher Education Institutions under Grant No.yx002001
文摘Traditional information hiding algorithms cannot maintain a good balance of capacity,invisibility and robustness.In this paper,a novel blind colour image information hiding algorithm based on grey prediction and grey relational analysis in the Discrete Cosine Transform(DCT) domain is proposed.First,this algorithm compresses the secret image losslessly based on the improved grey prediction GM(1,1)(IGM) model.It then chooses the blocks of rich texture in the cover image as the embedding regions using Double-dimension Grey Relational Analysis(DGRA).Finally,it adaptively embeds the compressed secret bits stream into the DCT domain mid-frequency coefficients,which are decided by those blocks' Double-Dimension Grey Correlation Degree(DGCD) and Human Visual System(HVS).This method can ensure an adequate balance between invisibility,capacity and robustness.Experimental results show that the proposed algorithm is robust against JPEG compression(46.724 6 dB when the compression quality factor is 90%),Gaussian noise(45.531 3 dB when the parameter is(0,0.000 5)) etc.,and it is a blind information hiding algorithm that can be extracted without an original carrier.
基金Under the auspices of the National Natural Science Foundation of China (No. 40571162)the Natural Science Foun-dation of Anhui Province (No. 050450401)
文摘Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.
文摘Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis .Results show that the rainfall in this area had a declining tendency in Spring at a rate of -21.2mm/10a, annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm, on the second place,with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm;and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.
文摘92 soil samples were collected from granite, basalt and limestone areas of eastern China and determined for 13 trace element contents. The geographical tendencies of and factors affecting trace element contents in soils were studied.The sequences of soil trace element contents (especially the transitional elements in the 4th period) were: basalt soils > limestone soils > granite soils.The contents of trace elements in soils of granite areas and basalt areas showed great inheritance of trace element contents from the relevant parent rocks. The contents of trace elements in limestones were very low, but they became very high in limestone soils. Trace element contents of soils derived from limestone and basalt'increased significantly from north to south, these tendencies were similar to the tendency of ferric oxide contents in soils.There were differences of contents of trace elements bound to ferric oxide in different kinds of parent material and in different types of soil. The correlations between the contents of trace elements and the contents of ferric oxide were better in basalt soils than in granite soils.
基金The authors are grateful to Dr. Lu Huayu from the State Key Laboratory of Loess and QuaternaryGeology for his assistance in field work. This work was supported by NKBRSF (G1999043400), National Natural Science Foundation of China (Grant No. 49725307) a
文摘Major and trace elements as well as strontium isotopic composition have been analyzed on the acid-insoluble (AI) phase of the loess-paleosol sequence from Luochuan, Shaanxi Province, China. Results show that the chemical composition of AI phase of loess and paleosols is distinctive to the average composition of upper continental crust (UCC), characterized by depletion of mobile elements Na, Ca and Sr. The distribution pattern of elements in AI phase reveals that initial dust, derived from a vast area of Asian inland, has suffered from Na- and Ca-removed chemical weathering compared to UCC. Some geochemical parameters (such as CIA values, Na/K, Rb/Sr and87Sr/86Sr ratios) display a regular variation and evolution, reflecting that the chemical weathering in the source region of loess deposits has decreased gradually since 2.5 Ma with the general increase of global ice volume. This coincidence reflects that the aridity of Asian inland since the Quaternary is a possible regional response to the global climate change.
