A Framework of Environmental Modelling and Information Sharing for Urban Air Pollution Control and Management

More effective environmental pollution control and management are needed due to the increasing environ-mental impacts from a range of human activities and the growing public demands for a better living environment. Urban air pollution is a serious environmental issue that poses adverse impacts on the health of people and the environment in most metropolitan areas. In this paper,we propose a geoinformatics augmented framework of environmental modelling and information sharing for supporting effective urban air pollution control and management. This framework is out-lined in terms of its key components and processes including: 1) an integrated,adaptive network of sensors for envi-ronmental monitoring; 2) a set of distributed,interoperable databases for data management; 3) a set of intelligent,robust algorithms and models for environmental modelling; 4) a set of flexible,efficient user interfaces for data access and in-formation sharing; and 5) a reliable,high capacity,high performance computing and communication infrastructure for integrating and supporting other framework components and processes.

Investigating spatial and temporal variations of soil moisture content in an arid mining area using an improved thermal inertia model

Mining operations can usually lead to environmental deteriorations. Underground mining activities could cause an extensive decrease in groundwater level and thus a dramatic variation in soil moisture content（SMC）. In this study, the spatial and temporal variations of SMC from 2001 to 2015 at two spatial scales（i.e., the Shendong coal mining area and the Daliuta Coal Mine） were analyzed using an improved thermal inertia model with a long-term series of Landsat TM/OLI（TM=Thematic Mapper and OLI=Operational Land Imager） data. Our results show that at large spatial scale（the Shendong coal mining area）, underground mining activities had insignificant negative impacts on SMC and that at small spatial scale（the Daliuta Coal Mine）, underground mining activities had significant negative impacts on SMC. Trend analysis of SMC demonstrated that areas with decreasing trend of SMC were mainly distributed in the mined area, indicating that underground mining is a primary cause for the drying trend in the mining region in this arid environment.

Environmental risk assessment of industrial byproduct gypsum utilized for flling abandoned mines

In response to the basic policy of green and low-carbon circular development to solve resource,environmental and ecological problems,gypsum is considered to be a flling material for mine backflling.To explore the potential risks of gypsum to the groundwater environment due to the backflling of abandoned mines,a sequential batch leaching experiment was carried out in this paper,which used three types of industrial waste gypsum,namely,phosphorus gypsum(PG),titanium gypsum(TG)and fue gas desulfurization gypsum(FGDG).COMSOL Multiphysics 5.4 software was used to simulate and solve the migration process of the leached metal elements in the mine foor when these three gypsum types were used as flling materials to observe the concentration distributions and difusion distances of the metal elements from these three gypsum types in the mine foor.The results show that(1)during repeated contact of the three types of industrial waste gypsum with the leaching medium,the pH levels changed,and the changes in pH afected the leaching patterns for the heavy metal elements in the gypsum.(2)Based on the concentrations of the metal elements that were leached from the three types of gypsum,it can be determined that these three types of gypsum are not classifed as hazardous solid wastes,but they cannot be ruled out with regard to their risk to the groundwater environment when they are used as mine flling materials.(3)When the three types of gypsum are used as flling materials,the concentration distributions of the metal elements and their migration distances all exhibit signifcant changes over time.The concentration distributions,difusion rates and migration distances of the metal elements from the diferent gypsum types are afected by their initial concentrations in the leachate.The maximum migration distances of Zn in the foor from the PG,FGDG and TG are 8.2,8.1 and 7.5 m,respectively.

Introduction for the Special Issue on Beyond the Hypes of Geospatial Big Data: Theories, Methods, Analytics, and Applications

We live in the era of‘Big Data’.In particular,Geospatial data,whether captured through remote sensors(e.g.,satellite imagery)or generated from large-scale simulations(e.g.,climate change models)have always been significantly large in size.Over the last decade however,advances in instrumentation and computation has seen the volume,variety,velocity,and veracity of this data increase exponentially.Of the 2.5 quintillion(1018)bytes of data that are generated on a daily basis across the globe,a large portion(arguably as much as 80%)is found to be geo-referenced.Therefore,this special issue is dedicated to the innovative theories,methods,analytics,and applications of geospatial big data.

Realization of an Optimal Dynamic Geodetic Reference Frame in China:Methodology and Applications

China Geodetic Coordinate System 2000(CGCS2000)has been used for several years as a formal published reference frame.The coordinates of all global navigation satellite system(GNSS)stations in China need to be corrected to align with the CGCS2000 frame.Different strategies can be adopted for the realization of an optimal reference frame.However,different strategies lead to different results,with differences as great as several decimeters when GNSS station coordinates are transformed into CGCS2000-defined coordinates.The two common methods for the coordinate correction of a GNSS station are quasi-stable adjustment under CGCS2000 and plate movement correction,and the differences between their results can be greater than 10 cm.In this study,a statistic method called"supervised clustering"is applied to the selection of GNSS reference stations;a new scheme named"partition spacing"for the grouping of all processed GNSS stations is proposed;and the plate movement correction method is used to correct the coordinates of all GNSS stations from the GNSS epoch to the CGCS2000 epoch.The results from the new partitioning method were found to be significantly better than those from the conventional station-blocking approach.When coordinates from the stations without grouping were used as the standard,the accuracy of all the three-dimensional coordinate components from the new partitioning method was better than 2 mm.The root mean squares(RMSs)of the velocities in the x,y,and z directions resulting from the supervised clustering method were 0.19,0.45,and 0.32 mm∙a1,respectively,which were much smaller than the values of 0.92,0.72,and 0.97 mm∙a1 that resulted from the conventional approach.In addition,singular spectrum analysis(SSA)was used to model and predict the position nonlinear movements.The modeling accuracies of SSA were better than 3,2,and 5 mm in the east(E),north(N),and up(U)directions,respectively;and its prediction accuracies were better than 5 mm and 1 cm for the horizontal and vertical domains,respectively.

A Data-Intensive FLAC^3D Computation Model:Application of Geospatial Big Data to Predict Mining Induced Subsidence

Although big data are widely used in various fields,its application is still rare in the study of mining subsidence prediction(MSP)caused by underground mining.Traditional research in MSP has the problem of oversimplifying geological mining conditions,ignoring the fluctuation of rock layers with space.In the context of geospatial big data,a data-intensive FLAC3D(Fast Lagrangian Analysis of a Continua in 3 Dimensions)model is proposed in this paper based on borehole logs.In the modeling process,we developed a method to handle geospatial big data and were able to make full use of borehole logs.The effectiveness of the proposed method was verified by comparing the results of the traditional method,proposed method,and field observation.The findings show that the proposed method has obvious advantages over the traditional prediction results.The relative error of the maximum surface subsidence predicted by the proposed method decreased by 93.7%and the standard deviation of the prediction results(which was 70 points)decreased by 39.4%,on average.The data-intensive modeling method is of great significance for improving the accuracy of mining subsidence predictions.

A Method for Rapidly Determining the Optimal Distribution Locations of GNSS Stations for Orbit and ERP Measurement Based on Map Grid Zooming and Genetic Algorithm

Designing the optimal distribution of Global Navigation Satellite System(GNSS)ground stations is crucial for determining the satellite orbit,satellite clock and Earth Rotation Parameters(ERP)at a desired precision using a limited number of stations.In this work,a new criterion for the optimal GNSS station distribution for orbit and ERP determination is proposed,named the minimum Orbit and ERP Dilution of Precision Factor(OEDOP)criterion.To quickly identify the specific station locations for the optimal station distribution on a map,a method for the rapid determination of the selected station locations is developed,which is based on the map grid zooming and heuristic technique.Using the minimum OEDOP criterion and the proposed method for the rapid determination of optimal station locations,an optimal or near-optimal station distribution scheme for 17 newly built BeiDou Navigation Satellite System(BDS)global tracking stations is suggested.To verify the proposed criterion and method,real GNSS data are processed.The results show that the minimum OEDOP criterion is valid,as the smaller the value of OEDOP,the better the precision of the satellite orbit and ERP determination.Relative to the exhaustive method,the proposed method significantly improves the computational efficiency of the optimal station location determination.In the case of 3 newly built stations,the computational efficiency of the proposed method is 35 times greater than that of the exhaustive method.As the number of stations increases,the improvement in the computational efficiency becomes increasingly obvious.

Protection Measures for Buildings Based on Coordinating Action Theory of Ground, Foundation and Structure

Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint effect of cur- vature deformation and horizontal deformation on buildings. It points out that for buildings over the coal pillar, it is ad- visable to soften the intermediate ground of buildings when they are affected by mining. For buildings over the goaf, it is preferable to soften the ground at both ends of buildings. In order to enhance the ability of a building to resist tensile deformation, the key measure is to reinforce the bottom foundation of the building. In addition, the concept of “angle of break of building” is proposed. It is because of this angle that the protecting coal pillar is left, which is a better solution than prevailing solutions The findings provide a more scientific basis for mining under buildings.

Exploring Urban Population Forecasting and Spatial Distribution Modeling with Artificial Intelligence Technology

The high precision population forecasting and spatial distribution modeling are very important for the theory and application of population sociology,city planning and Geo-Informatics.However,the two problems need to be solved for providing the high precision population information.One is how to improve the population forecasting precision of small area(e.g.,street scale);another is how to improve the spatial resolution of urban population distribution model.To solve the two problems,some new methods are proposed in this contribution.(1)To improve the precision of small area population forecasting,a new method is developed based on the fade factor and the slide window.(2)To improve the spatial resolution of urban population distribution model,a new method is proposed based on the land classification,public facility information and the artificial intelligence technology.For validation of the proposed methods,the real population data of 15 streets in Xicheng district,Beijing,China from 2010 to 2016,the remote sensing images and the public facility data are collected and used.A number of experiments are performed.The results show that the spatial resolution of proposed model reaches 30m*30m and the forecasting precision is better than 5%using the proposed method to forecast the population of 15 streets in Xicheng district in the next four years.

Characteristics of water contamination in abandoned coal mines:a case study on Yudong River area,Kaili,Guizhou Province,China

The seasonal and spatial changes in the chemical composition of the water in abandoned mine drainages and rivers in Yudong River area in the years of 2017-2018 were analyzed.The effects of mine water drainage on the seasonality and physicochemical properties of the river water after mine closure were evaluated,and the feasibility of irrigation using river water and the degree of pollution to farmland were assessed using the Water Quality Standard for Farmland Irrigation.The results show that the mine water has low pH value(<3.5-4)and high levels of total hardness,SO_(4)^(2−),Fe,Al,and Zn.In addition,the pH of the mine water is negatively correlated with the presence of other metal ions.The correlation coefficient between the chemical oxygen demand(COD)and Fe reached 0.989.While the pollution levels of Pinglu and Baishui rivers were low,the confluence region of the two rivers was seriously polluted.However,only the levels of Fe and Cd slightly exceeded the Surface Water Environmental Quality Standard after the confluence of Yudong and Chongan rivers.Overall,the heavy pollution type of the confluent river is consistent with mine water pollution.The water quality is slightly better in the dry season compared than in the high-water period.Sulfate and Fe content decreased by 39 and 16 mg/L,respectively,and Cd content decreased two-fold.Despite these findings,this study shows that from 2017 to 2018,the pH and Cd content of the rivers at the confluence exceeded the irrigation limit and the water quality continued to deteriorate,which may pose a soil contamination risk.Long-term use of the river for irrigation water may cause toxic elements such as Cd,Fe,Mn,SO_(4)^(2−),Al,and F-to enter the food chain,thereby endangering the life and health of villagers in Yudong River area.

Effects of acid drainage from abandoned coal mines on the microbial community of Shandi River sediment,Shanxi Province

The discharge of acid mine drainage from abandoned high sulfur(S)coal mines has caused serious pollution in the Shandi River,Yangquan,Shanxi Province.To determine the impact of long-term acid mine drainage on the microorganisms in the river,we collected river sediments from a polluted tributary(Group P)and the mainstream of Shandi River(Group R)to study the bacterial diversity and community composition.The results showed that the tributary was seriously polluted by acid drainage from abandoned coal mines,with the pH value of the sediment being<2.5,resulting in the low bacterial richness and diversity of the tributary samples.Acidophillic Fe-and S-metabolizing bacteria,such as Metallibacterium,Acidiphilium,and Acidithiobacillus,were the dominant genera in Group P samples,while the Group R was dominated by the neutral anaerobic iron-reducing bacteria Geothrix and Geobacter.Results of principal co-ordinates analysis(PCoA)revealed that the bacterial communities are significantly different between groups P and R,and the significant different species were mainly attributed to phylum Proteobacteria,Actinobacteria,and Acidobacteria.The distribution of the microbial community is mainly influenced by pH,and the Fe and Cd concentrations.Metallicactrium,the dominant genus,is negatively correlated with pH(R^(2)=-0.95)and positively correlated with Fe(R^(2)=0.99),while Geothrix and Geobacter,are mainly affected by the heavy metals.This study determined the impact of river pollution caused by abandoned coal mine drainage,especially on the microbial diversity and community composition within the river sediment.

Optimization of Well Position and Sampling Frequency for Groundwater Monitoring and Inverse Identification of Contamination Source Conditions Using Bayes’Theorem

Coupling Bayes’Theorem with a two-dimensional(2D)groundwater solute advection-diffusion transport equation allows an inverse model to be established to identify a set of contamination source parameters including source intensity(M),release location(0 X,0 Y)and release time(0 T),based on monitoring well data.To address the issues of insufficient monitoring wells or weak correlation between monitoring data and model parameters,a monitoring well design optimization approach was developed based on the Bayesian formula and information entropy.To demonstrate how the model works,an exemplar problem with an instantaneous release of a contaminant in a confined groundwater aquifer was employed.The information entropy of the model parameters posterior distribution was used as a criterion to evaluate the monitoring data quantity index.The optimal monitoring well position and monitoring frequency were solved by the two-step Monte Carlo method and differential evolution algorithm given a known well monitoring locations and monitoring events.Based on the optimized monitoring well position and sampling frequency,the contamination source was identified by an improved Metropolis algorithm using the Latin hypercube sampling approach.The case study results show that the following parameters were obtained:1)the optimal monitoring well position(D)is at(445,200);and 2)the optimal monitoring frequency(Δt)is 7,providing that the monitoring events is set as 5 times.Employing the optimized monitoring well position and frequency,the mean errors of inverse modeling results in source parameters(M,X0,Y0,T0)were 9.20%,0.25%,0.0061%,and 0.33%,respectively.The optimized monitoring well position and sampling frequency canIt was also learnt that the improved Metropolis-Hastings algorithm(a Markov chain Monte Carlo method)can make the inverse modeling result independent of the initial sampling points and achieves an overall optimization,which significantly improved the accuracy and numerical stability of the inverse modeling results.

Modeling and Prediction of Inter-System Bias for GPS/BDS-2/BDS-3 Combined Precision Point Positioning

The combination of Precision Point Positioning(PPP)with Multi-Global Navigation Satellite System(MultiGNSS),called MGPPP,can improve the positioning precision and shorten the convergence time more effectively than the combination of PPP with only the BeiDou Navigation Satellite System(BDS).However,the Inter-System Bias(ISB)measurement of Multi-GNSS,including the time system offset,the coordinate system difference,and the inter-system hardware delay bias,must be considered for Multi-GNSS data fusion processing.The detected ISB can be well modeled and predicted by using a quadratic model(QM),an autoregressive integrated moving average model(ARIMA),as well as the sliding window strategy(SW).In this study,the experimental results indicate that there is no apparent difference in the ISB between BDS-2 and BDS-3 observations if B1I/B3I signals are used.However,an obvious difference in ISB can be found between BDS-2 and BDS-3 observations if B1I/B3I and B1C/B2a signals are used.Meanwhile,the precision of the Predicted ISB(PISB)on the next day of all stations is about 0.1−0.6 ns.Besides,to effectively utilize the PISB,a new strategy for predicting the PISB for MGPPP is proposed.In the proposed strategy,the PISB is used by adding two virtual observation equations,and an adaptive factor is adopted to balance the contribution of the Observed ISB(OISB)and the PISB to the final estimations of ISB.To validate the effectiveness of the proposed method,some experimental schemes are designed and tested under different satellite availability conditions.The results indicate that in open sky environment,the selective utilization of the PISB achieves almost the same positioning precision of MGPPP as the direct utilization of the PISB,but the convergence time of MGPPP is reduced by 7.1%at most in the north(N),east(E),and up(U)components.In the blocked sky environment,the selective utilization of the PISB contributes to more significant improvement of the positioning precision and convergence time than that in the open sky environment.Compared with the direct utilization of the PISB,the selective utilization of the PISB improves the positioning precision and convergence time by 6.7%and 12.7%at most in the N,E,and U components,respectively.

Distribution and modes of occurrence of uranium in coals of Eastern Yunnan,China

Uranium is an environmentally hazardous element,and is commonly present at trace levels(2.4 μg/g for world coals)in coal deposits.However,selected coal deposits could be highly enriched in uranium.In this study,15 coal samples were collected from Eastern Yunnan coal deposits,China,aiming to characterize the distribution and the occurrence of uranium in those coals.In studied samples,uranium content varied from 0.36 to 8.28 μg/g,with an average value of 3.76 lg/g.Generally,uranium content in coals from northern coal mines(3.02±2.44 μg/g,n=5)were lower than it in southern coal mines(4.13±2.30 μg/g,n=10).Uranium in coal samples showed no obvious correlation with total sulfur,whereas was positively correlated with ash yield.The results of sequential chemical extraction procedure confirm that organic-bound is the dominant occurrence of uranium.The slight enrichment of uranium in studied coals was probably attributed to sedimentation processes,hydrological conditions and tectonic structure of the coal deposits.

Evaluation and comparison of CMIP6 models and MERRA-2 reanalysis AOD against Satellite observations from 2000 to 2014 over China

Rapid industrialization and urbanization along with a growing population are contributing significantly to air pollution in China.Evaluation of long-term aerosol optical depth(AOD)data from models and reanalysis,can greatly promote understanding of spatiotemporal variations in air pollution in China.To do this,AOD(550 nm)values from 2000 to 2014 were obtained from the Coupled Model Intercomparison Project(CIMP6),the second version of Modern-Era Retrospective analysis for Research,and Applications(MERRA-2),and the Moderate Resolution Imaging Spectroradiometer(MODIS;flying on the Terra satellite)combined Dark Target and Deep Blue(DTB)aerosol product.We used the TerraMODIS DTB AOD(hereafter MODIS DTB AOD)as a standard to evaluate CMIP6 Ensemble AOD(hereafter CMIP6 AOD)and MERRA-2 reanalysis AOD(hereafter MERRA-2 AOD).Results show better correlations and smaller errors between MERRA-2 and MODIS DTB AOD,than between CMIP6 and MODIS DTB AOD,in most regions of China,at both annual and seasonal scales.However,significant under-and over-estimations in the MERRA-2 and CMIP6 AOD were also observed relative to MODIS DTB AOD.The long-term(2000-2014)MODIS DTB AOD distributions show the highest AOD over the North China Plain(0.71)followed by Central China(0.69),Yangtse River Delta(0.67),Sichuan Basin(0.64),and Pearl River Delta(0.54)regions.The lowest AOD values were recorded over the Tibetan Plateau(0.13±0.01)followed by Qinghai(0.19±0.03)and the Gobi Desert(0.21±0.03).Large amounts of sand and dust particles emitted from natural sources(the Taklamakan and Gobi Deserts)may result in higher AOD in spring compared to summer,autumn,and winter.Trends were also calculated for 2000-2005,for2006-2010(when China introduced strict air pollution control policies during the 11 th Five Year Plan or FYP),and for 2011-2014(during the 12 th FYP).An increasing trend in MODIS DTB AOD was observed throughout the country during 2000-2014.The uncontrolled industrialization,urbanization,and rapid economic development that mostly occurred from 2000 to 2005 probably contributed to the overall increase in AOD.Finally,China’s air pollution control policies helped to reduce AOD in most regions of the country;this was more evident during the 12 th FYP period(2011-2014)than during the 11 th FYP period(2006-2010).Therefore this study strongly advises the authority to retain or extend these policies in the future for improving air quality.

Study of probability integration method parameter inversion by the genetic algorithm

In order to obtain accurate probability integration method(PIM) parameters for surface movement of multi-panel mining, a genetic algorithm(GA) was used to optimize the parameters. As the measured surface movement is affected by more than one mining panel, traditional PIM parameter inversion model is difficult to ensure the reliability of the results due to the complexity of rock movement. With crossover,mutation and selection operators, GA can perform a global optimization search and has high computation efficiency. Compared with the pattern search algorithm, the fitness function can avoid falling into local minima traps. GA reduces the risk of local minima traps which improves the accuracy and reliability with the mutation mechanism. Application at Xuehu colliery shows that GA can be used to inverse the PIM parameters for multi-panel surface movement observation, and reliable results can be obtained. The research provides a new way for back-analysis of PIM parameters for mining subsidence under complex conditions.

Spatio-temporal dynamics of vegetation in Jungar Banner of China during 2000–2017

It is known that the exploitation of opencast coal mines has seriously damaged the environments in the semi-arid areas.Vegetation status can reliably reflect the ecological degeneration and restoration in the opencast mining areas in the semi-arid areas.Long-time series MODIS NDVI data are widely used to simulate the vegetation cover to reflect the disturbance and restoration of local ecosystems.In this study, both qualitative(linear regression method and coefficient of variation(CoV)) and quantitative(spatial buffer analysis, and change amplitude and the rate of change in the average NDVI) analyses were conducted to analyze the spatio-temporal dynamics of vegetation during 2000–2017 in Jungar Banner of Inner Mongolia Autonomous Region, China, at the large(Jungar Banner and three mine groups) and small(three types of functional areas: opencast coal mining excavation areas, reclamation areas and natural areas) scales.The results show that the rates of change in the average NDVI in the reclamation areas(20%–60%) and opencast coal mining excavation areas(10%–20%) were considerably higher than that in the natural areas(<7%).The vegetation in the reclamation areas experienced a trend of increase(3–5 a after reclamation)-decrease(the sixth year of reclamation)-stability.The vegetation in Jungar Banner has a spatial heterogeneity under the influences of mining and reclamation activities.The ratio of vegetation improvement area to vegetation degradation area in the west, southwest and east mine groups during 2000–2017 was 8:1, 20:1 and 33:1, respectively.The regions with the high CoV of NDVI above 0.45 were mainly distributed around the opencast coal mining excavation areas, and the regions with the CoV of NDVI above 0.25 were mostly located in areas with low(28.8%) and medium-low(10.2%) vegetation cover.The average disturbance distances of mining activities on vegetation in the three mine groups(west, southwest and east) were 800, 800 and 1000 m, respectively.The greater the scale of mining, the farther the disturbance distances of mining activities on vegetation.We conclude that vegetation reclamation will certainly compensate for the negative impacts of opencast coal mining activities on vegetation.Sufficient attention should be paid to the proportional allocation of plant species(herbs and shrubs) in the reclamation areas, and the restored vegetation in these areas needs to be protected for more than 6 a.Then, as the repair time increased, the vegetation condition of the reclamation areas would exceed that of the natural areas.

Land Surface Displacement Geohazards Monitoring Using Multi-temporal InSAR Techniques

China has been affected by some of the world’s most serious geological disasters and experiences high economic damage every year.Geohazards occur not only in remote areas but also in highly populated cities.In the framework of the Dragon-432365 Project,this paper presents the main results and the major conclusions derived from an extensive exploitation of Sentinel-1,ALOS-2(Advanced Land Observing Satellite 2),GF-3(Gao Fen Satellite 3),and latest launched SAR(Synthetic Aperture Radar),together with methods that allow the evaluation of their importance for various geohazards.Therefore,in the scope of this project,the great benefits of recent remote sensing data(wide spatial and temporal coverage)that allow a detailed reconstruction of past displacement events and to monitor currently occurring phenomena are exploited to study different areas and geohazards problems,including:surface deformation of mountain slopes;identification and monitoring of ground movements and subsidence;landslides;ground fissure;and building inclination studies.Suspicious movements detected in the different study areas were cross validated with different SAR sensors and truth data.

Aspect in Topography to Enhance Fine-detailed Landform Element Extraction on High-resolution DEM

The value of the high-resolution data lies in the high-precision information discovery.The fine-detailed landform element extraction is thus the basis of high-fidelity application of the high-resolution digital elevation models(DEMs).However,the results of landform element extraction generated by classical methods might be ungrounded on high-resolution DEMs.This paper presents our research on using the aspect to reinforce the applicability and robustness of the classical approaches in landform element extraction.First,according to the research of pattern recognition,we assume that aspect-enhanced landform representation is robust to rotation,scaling and affine variance.To testify the role of aspect,we respectively integrated the aspect into three classical approaches:mean curvaturebased fuzzy classification,elevation-based feature descriptor,and object-based segmentation.In the experiment,based on four types of high-resolution DEMs(1 m,2 m,4 m and 8 m),we compare each classical approaches and their corresponding aspect-enhanced approaches based on extracting the rims of two craters having different landforms,and the ridgelines and valleylines of a region covered by few vegetables and man-made buildings.In comparison to the results generated by curvature-based fuzzy classification,the aspect enhanced curvature-based fuzzy classification can effectively filter a number of noises outperforms the curvature-based one.Otherwise,the aspect-enhanced feature descriptor can detect more landform elements than the elevation-based feature descriptor.Moreover,the aspect-based segmentation can detect the main structure of landform,while the boundaries segmented by classical approaches are messing and meaningless.The systematic experiments on meter-level resolution DEMs proved that the aspect in topography could effectively to improve the classical method-system,including fuzzy-based classification,feature descriptors-based detection and object-based segmentation.The value of aspect is significantly great to be worthy of attentions in landform representation.

The Unified Dynamic Theory and Its Engineering Research

The unified dynamic theory reveals the substrate-based nonlinear growth phenomena.It means that the environment of high organism concentration and low substrate state is useful for the growth of weak floras.With ecological superior nitrification denitrification(ECOSUNIDE) technology,high sludge concentration by distributing influent to anaerobic and anoxic zones is carried out,and the ecological superiorities of nitrifiers,denitrifiers,and phosphate accumulating organisms(PAOs) get to be promoted.One of the anaerobic/anoxic/oxic(A/A/O) treatment lines of a sewage treatment plant with ECOSUNIDE technology for further investigation on the nutrient removal efficiency is reformed.The advantages of ECOSUNIDE,such as high efficiency and saving energy,are well demonstrated,even under the condition of low temperature(about 15℃) and carbon-resource(C/N ratio lower than 2.5).In ECOSUNIDE system,the effluent indexes as biochemical oxygen demand(BOD),chemical oxygen demand(COD),and NH3-N reach the ClassⅠ-A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB18918-2002),and suspended substance(SS),total nitrogen(TN),and total phosphorus(TP) meet the ClassⅠ-B criteria.While the effluent qualities of A/A/O system only reach the secondary discharge standard.Through the comparison on the sludge character of ECOSUNIDE system with A/A/O,more abundant biofacies,darker and more intense zoogloea,more obvious filamentous bacterium,and clearer flocs edges in ECOSUNIDE system are found.