基于ρ域源模型的H.264宏块行层码率控制算法

在H.264中,对于一个宏块行,ρ与比特率仍然满足线性关系。基于此,提出了基于ρ域源模型的H.264宏块行层码率控制算法。在宏块行间,根据第一次RDO时各个宏块行所耗用比特数的百分比来分配比特数。实验结果表明,与JM8.4中采用的码率控制算法相比,本文提出的宏块行层码率控制算法在保证基本相同的编码效率情况下,能显著降低比特数估计偏差,更好地跟踪目标码率。

一种新的SAR图像目标检测方法

基于统计特性的恒虚警率(CFAR)算法和小波多分辨率分析方法很难检测到微弱的、小的和隐藏的目标。合成孔径雷达(SAR)成像机理是相干成像,相干相位信息为目标的检测提供了可能性。从相干成像机理出发,结合恒虚警率和背景杂波分布模型,提出了一种新的SAR图像目标检测算法,即相干性CFAR目标检测算法,并且针对图像相干源提出了亚像元空间域源算法。实验证明,该方法是可行的、有效的,有利于SAR图像的理解和应用。

Slope displacement prediction based on multisource domain transfer learning for insufficient sample data

Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displacement difficult.Moreover,in engineering practice,insufficient monitoring data limit the performance of prediction models.To alleviate this problem,a displacement prediction method based on multisource domain transfer learning,which helps accurately predict data in the target domain through the knowledge of one or more source domains,is proposed.First,an optimized variational mode decomposition model based on the minimum sample entropy is used to decompose the cumulative displacement into the trend,periodic,and stochastic components.The trend component is predicted by an autoregressive model,and the periodic component is predicted by the long short-term memory.For the stochastic component,because it is affected by uncertainties,it is predicted by a combination of a Wasserstein generative adversarial network and multisource domain transfer learning for improved prediction accuracy.Considering a real mine slope as a case study,the proposed prediction method was validated.Therefore,this study provides new insights that can be applied to scenarios lacking sample data.

Comparison of the time-domain electromagnetic field from an infinitesimal point charge and dipole source

An electromagnetic field is generated through the accelerating movement of two equal but opposite charges of a single dipole. An electromagnetic field can also be generated by a time-varying infinitesimal point charge. In this study, a comparison between the electromagnetic fields of an infinitesimal point charge and a dipole has been presented. First, the time-domain potential function of a point source in a 3D conductive medium is derived. Then the electric and magnetic fields in a 3D homogeneous lossless space are derived via the relation between the potential and field. The field differences between the infinitesimal point charge and the dipole in the step-off time, far-source, and near-source zones are analyzed, and the accuracy of the solutions from these sources is investigated. It is also shown that the field of the infinitesimal point charge in the near-source zone is different from that of the dipole, whereas the far-source zone fields of these two sources are identical. The comparison of real and simulated data shows that the infinitesimal point charge represents the real source better than the divole source.

New method to compute the throughput capacity of HDR wireless networks

A new non-parameter method is proposed to compute the throughput capacity region of high data rate (HDR) wireless networks. We first transform the task of computing the throughput capacity region into a mathematical optimization problem without introducing any additional parameters. By using a greedy algorithm to solve the optimization problem, the non-parametric characterization of the throughput capacity region of HDR can be obtained. By using the new non-parameter method, the HDR throughput capacity region can be characterized by at most N(M2-M+1)N-1 linear constraints where N is the user number and M is the rate set size. The correctness of the new method is verified by several numerical examples.

Effects of Different Water Stresses on Eco-physiological Characteristics of Hippophae rhamnoides Seedlings

In order to examine the effects of the decrease of future precipitation on the eco-physiological characteristics of sea buckthorn (Hippophae rhamnoides Linn.) in Huangfuchuan Watershed in Nei Mongol, a water gradient experiment was conducted based on the four specially designed water supply levels, including normal precipitation, slight drought, drought and extreme drought. Results of ANOVE showed that different water gradients had a significant effect on (1) microhabitat factors, such as soil water content and soil temperature; (2) gas exchange, such as net photosynthetic rate, stomatal conductance and transpiration rate; (3) resource use efficiency; and (4) leaf water potential. Water use efficiency of H rhamnoides could increase under moderate water stress, i.e. drought condition, while its net photosynthetic rate and transpiration rate decreased. All kinds of eco-physiological characteristics proved H. rhamnoides seedlings under all water supplies were affected by water stress more or less and that mechanism of intrinsic physiological regulation in seedlings under the extreme drought conditions had the appearance of turbulence to a certain extent. Therefore, H rhamnoides seedlings in Huangfuchuan Watershed could not acclimate to extreme drought conditions.

Analysis on Strategic Future of Application of Agricultural Ecological Source in Control on Agricultural Nonpoint Source Pollution in Xi River Area in Guangxi

Non-point source pollution has become a hot issue on aquatic ecological environment at home and abroad. The research analyzed the challenges confronted by Xi River and proposed to construct agricultural ecological source in middle and upper reaches of the Xi River from the perspectives of scientific layout, legal construction, routine monitoring, technology integration, and coordination system in order to promote sustainable development of eco-environment in Xi River.

An Overview of the Concept of Regional Sediment Management

In this article we described the concept of ＂regional sediment management＂ （RSM）, and identified opportunities for and impediments to implementing regional approaches to sediment management, and also summarized the background information and applications of RSM. Furthermore, we considered the needs of RSM studies and, suggested the framework for developing RSM strategies, and described the specific studies for the Xiamen region.

Current Situation and Control Measures of Agricultural Non-point Source Pollution in Typical Basin of South China

In view of the serious non-point source pollution of agriculture in the areas where crop production is concentrated in southern China,the present situation of agricultural non-point source pollution in southern watershed and the main technical measures adopted in the practice of comprehensive prevention and control in recent years are analyzed from the perspectives of different pollution sources such as planting,livestock and poultry breeding,aquaculture and village area runoff.From the perspective of functional restoration and optimization of farmland ecosystem,the countermeasures are put forward,such as strengthening the control of high qualityoriented pollution reduction,layout optimization,constructing circulation system and improving management system,constructing comprehensive prevention and control strategies for ecosystem elements and material exchange,energy flow and logistics linkage,information flow exchange,and maintaining and improving the ability of agricultural ecosystem itself to absorb non-point source pollution.

Analysis of Water Quality of Yangtze River through Jiangsu Province

The Yangtze River flows through Jiangsu Province, bringing abundant water resources to people in this province. However, environmental pollution and destruction of vegetation in recent years have led to deterioration of water quality of the Yangtze, bringing about many bad effects on people’s life and production. Through a comprehensive analysis of water quality of the Yangtze River through Jiangsu Province, we investigated the reasons for the deterioration of its water quality, and explored countermeasure to maintain good water quality in the Yangtze with the objective to provide safe and reliable drinking water sources for people.

Trends of surface PM_(2.5) over Beijing–Tianjin–Hebei in 2013–2015 and their causes: emission controls vs. meteorological conditions

The PM2.5 （particulate matter with a diameter of less than 2.5 μm） trends during the period 2013- 2015, in 13 cities over the Beijing-Tianjin-Hebei region, and their causes, were investigated using observations at 75 stations and a regional air quality model. It was found that annual PM2.5 in this region experienced a significant decrease in 2014 and 2015, compared with 2013. PM2.s in 2015 almost met the target on air quality in the 13th Five-Year Plan （2012-2017）. In southern cities （e.g. Xingtai, Handan, Shijiazhuang, and Cangzhou）, this PM2.5 decreasing trend was caused by both meteorological conditions and regional emission controls in 2014 and 2015. Contributions from regional emission controls were more significant than meteorological conditions. In Tianjin and Langfang, the impact of regional emission controls was partly offset by the meteorological conditions in 2014. In 2015, meteorological conditions turned favorable for a PM2.s decrease, but emission controls were still the dominant cause. Compared with polluted cities in Hebei and Tianjin, the decreasing trend in Beijing was small （4% and 9% in 2014 and 2015）.This reflects the competition between adverse meteorological conditions and emission controls. In northern cities （Tangshan, Qinhuangdao, and Zhangjiakou）, regional emission controls dominated the PM2.5 decreasing trend in 2014 and 2015, although they were partly offset by meteorological conditions. In all cities during the heating season in 2015, a more significant decreasing trend of high PM2.5 from emission controls was found than low and middle PM2.5. This indicates that air pollution controls are developing towards refined management （e.g. the Heavy Air Pollution Emergency Response Program） in this region.

A two-stage frequency-domain blind source separation method for underdetermined instantaneous mixtures

In order to decrease the probability of missing some data points or noises being added in the inverse truncated mixing matrix （ITMM） algorithm, a two-stage frequency- domain method is proposed for blind source separation of underdetermined instantaneous mixtures. The separation process is decomposed into two steps of ITMM and matrix completion in the view that there are many soft-sparse （not very sparse） sources. First, the mixing matrix is estimated and the sources are recovered by the traditional ITMM algorithm in the frequency domain. Then, in order to retrieve the missing data and remove noises, the matrix completion technique is applied to each preliminary estimated source by the traditional ITMM algorithm in the frequency domain. Simulations show that, compared with the traditional ITMM algorithms, the proposed two-stage algorithm has better separation performances. In addition, the time consumption problem is considered. The proposed algorithm outperforms the traditional ITMM algorithm at a cost of no more than one- fourth extra time consumption.

Evaluation of regional energy security in eastern coastal China based on the DPSIR model

The DPSIR assessment method, which implies the relationships among driving force （D）, pressure （P）, status （S）, impact （I）, and response （R）, is widely applied by scholars. This paper aims to establish a comprehensive assessment system for regional energy security in eastern coastal China based on the above model using different indicators. Factor analysis and the SPSS statistical analysis software were used to carry out scientific and quantitative assessments. The results indicated that con- tradictions of energy supply and demand as well as environmental pollution are the critical factors that present great challenges to regional energy security in this area. The authors argued that a sustainable, stable, and safe supply energy supply is crucial in solving the aforesaid dilemma, and improving the energy use efficiency is one of the best choices. Some countermeasures and suggestions regarding regional energy supply stability and utilization security were pointed out.

Regional Distribution and Sustainable Development Strategy of Mineral Resources in China

This paper summarizes the distribution and production layout of the major mineral resources in China,including coal,iron ore,copper and bauxite,from a national perspective.It also identifies the incompatibility between the mineral resources distribution and regional economic development.Significant issues with China's mineral resource industry cause challenges for the sustainable development of both the mining industry and the national socio-economy.The sustainability of regional mineral resources and the environmental pollution by mining in the western China were also analyzed.Results show that the distribution of China's mineral resources is misaligned with its regional layout of economic development.China's mineral resources have been over-exploited,and the mineral resources production in the eastern China is unsustainable.The continuously expanding production of mineral resources in the western China has heavily endangered the ecological environment.We propose strategies to boost the sustainable development of mineral resources,including measures to accelerate economic development and enhance the sustainability of domestic mineral resources.We also offer suggestions for scientifically planning the mineral resource prospecting and exploitation and regional economic layout,as well as for proactively undertaking industry transfer in the eastern China and raising the environmental benchmark requirements for the mineral industry in the central and western China.

A WEIGHTED GENERAL DISCRETE FOURIER TRANSFORM FOR THE FREQUENCY-DOMAIN BLIND SOURCE SEPARATION OF CONVOLUTIVE MIXTURES

This letter deals with the frequency domain Blind Source Separation of Convolutive Mixtures (CMBSS). From the frequency representation of the "overlap and save", a Weighted General Discrete Fourier Transform (WGDFT) is derived to replace the traditional Discrete Fourier Transform (DFT). The mixing matrix on each frequency bin could be estimated more precisely from WGDFT coefficients than from DFT coefficients, which improves separation performance. Simulation results verify the validity of WGDFT for frequency domain blind source separation of convolutive mixtures.

Evaluation of CMPAS precipitation products over Sichuan,China

High-quality and high-resolution precipitation data are the basis for mesoscale numerical weather forecasting,model verification,and hydrological monitoring,which play an important role in meteorological and hydrological disaster prevention and mitigation.In this study,high-density rain gauge data are used to evaluate the fusion accuracy of the China Meteorological Administration Multisource Precipitation Analysis System(CMPAS),and four CMPAS products with different spatial and temporal resolution and different data sources are compared,to derive the applicability of CMPAS.Results show that all the CMPAS products show high accuracy in the Sichuan Basin,followed by Panxi Area and the western Sichuan Plateau.The errors of the four products all rise with the increase in precipitation.CMPAS overestimates precipitation in summer and autumn and underestimates it in spring and winter.Overall,the applicability of these fused data in the Sichuan Basin is quite good.Due to the lack of observations and the influence of the terrain and meteorological conditions,the evaluation of CMPAS in the plateau area needs further analysis.

Distribution and Provenance of Detrital Minerals in Southern Coast of Shandong Peninsula

Detrital minerals of 137 offshore and 22 river sediment samples collected from Qingdao coastal areas have been analyzed. Four mineral assemblage provinces can be classified by Q-mode cluster analysis. Factor analysis identifies two major factors that account for the total variability in most common minerals: 1) based on the relationship of quartz, hornblende, actinolite, micas, and authigenic pyrite, 41.55% of the variability is related to sediment sources; 2) based on the relationship of epidote, garnet, sphere, and ilmenite, 23.21% can be related to strong hydrodynamic conditions that control transport and sedimentation. By comparing mineral compositions of river waters in the study area, the following four mineral provenances can be identified. The Qingdao-Laoshan nearshore area has a quartz-feldspar-epidote-hornblende-limenite-limonite-sphene assemblage, which is largely attributed to relict sediment and coastal erosion. The Jimo-Haiyang nearshore area has a quartz-feldspar-hornblende-epidote-limonite-mica-actinolite assemblage, derived largely from the Wulong River and Rushan River, and is also affected by the Huanghe River, while the Qianliyan Island area in the deeper offshore area separated by a mud belt has a similar assemblage. The Haiyang-Rushan nearshore area has a quartz-feldspar-hornblende-epidote-micas-limonite assemblage, indicating multiple sources from the Rushan River, the Wulong River, the Huanghe River, and coastal erosion. The central area, located in an eddy center, has a mica-authigenic pyrite-hornblende-quartz-feldspar assemblage, indicating multiple sources dominated by Huanghe River distal sediments.

Karst Cave Tourism System in Zhejiang Province Based on Resource Regional Analysis

Karst cave tourism plays an important role in the overall tourism of Zhejiang Province, China. In analyzing the current status of karst cave tourism resources, it is crucial to develop a scientific system for optimizing resource exploitation and tourism development in the future. This study conducted an analysis of resource characteristics and regional structure in Zhejiang Province. Nearest neighbor index （NNI） method and accessibility index method were used for a comprehensive understanding of the effects of scale, strength, combination, and accessibility of karst cave tourism resources. Results indicated that karst cave tourism resources in Zhejiang Province have a significant regional influence, and that resource quality and exploitation are diverse in different regions. Among the regions, Jinhua had the highest exploitation proportion of over 60% and the lowest NNI value of 0.098. Furthermore, regional analysis inferred that different karst caves demonstrate diversity in accessibility to tourism markets, among which the Lingshan Cave, Fengshui Cave, and Xianqiao Cave reveal the highest accessibility index of 2.41. Finally, we put forward a karst cave tourism system in Zhejiang Province based on the Growth Pole Theory and set up an overall scheme for karst cave tourism development. From a regional perspective analysis, the study refined the methods for regional resource re- search and provided a strategic proposal for karst cave tourism in Zheiiang Province.

Quantitative Estimation on Contributions of Climate Changes and Human Activities to Decreasing Runoff in Weihe River Basin, China

Human activities and climate changes are deemed to be two primary driving factors influencing the changes of hydrological processes, and quantitatively separating their influences on runoff changes will be of great significance to regional water resources planning and management. In this study, the impact of climate changes and human activities was initially qualitatively distinguished through a coupled water and energy budgets analysis, and then this effect was further separated by means of a quantitative estimation based on hydrological sensitivity analysis. The results show that: 1) precipitation, wind speed, potential evapotranspiration and runoff have a significantly decreasing trend, while temperature has a remarkably increasing tendency in the Weihe River Basin, China; 2) the major driving factor on runoff decrease in the 1970 s and 1990 s in the basin is climate changes compared with that in the baseline 1960 s, while that in the 1980 s and 2000 s is human activities. Compared with the results based on Variable Infiltration Capacity(VIC) model, the contributions calculated in this study have certain reliability. The results are of great significance to local water resources planning and management.

Impacts of Global Warming Perturbation on Water Resources in Arid Zone: Case Study of Kaidu River Basin in Northwest China

The main goal of this study was to assess the long-term impacts of global warming perturbation on water resources of the Kaidu River Basin in Northwest China. Temperature, precipitation and hydrology data during the past 29 years from 1979 to 2007 were collected and analyzed using parametric and non-parametric methods, the connection between temperature and precipitation by the combination of grey correlation analysis method and the hypothesis testing for trend of climate change. The results show a high increase in temperature in the study area as well as an extreme and highly variable hydrological regime in this region, where flash floods can exceed the total runoff from a sequence of years. These variations may be due to the geographical location of the Kaidu River Basin in arid zone. It also reveals that precipitation has a much greater impact on stream flow than that of temperature. The development of new approaches was proposed as responses to climate change in this arid region.