Comprehensive Survey of the Landscape of Digital Twin Technologies and Their Diverse Applications

The concept of the digital twin,also known colloquially as the DT,is a fundamental principle within Industry 4.0 framework.In recent years,the concept of digital siblings has generated considerable academic and practical interest.However,academia and industry have used a variety of interpretations,and the scientific literature lacks a unified and consistent definition of this term.The purpose of this study is to systematically examine the definitional landscape of the digital twin concept as outlined in scholarly literature,beginning with its origins in the aerospace domain and extending to its contemporary interpretations in the manufacturing industry.Notably,this investigationwill focus on the research conducted on Industry 4.0 and smartmanufacturing,elucidating the diverse applications of digital twins in fields including aerospace,intelligentmanufacturing,intelligent transportation,and intelligent cities,among others.

Multimodal Deep Neural Networks for Digitized Document Classification

As digital technologies have advanced more rapidly,the number of paper documents recently converted into a digital format has exponentially increased.To respond to the urgent need to categorize the growing number of digitized documents,the classification of digitized documents in real time has been identified as the primary goal of our study.A paper classification is the first stage in automating document control and efficient knowledge discovery with no or little human involvement.Artificial intelligence methods such as Deep Learning are now combined with segmentation to study and interpret those traits,which were not conceivable ten years ago.Deep learning aids in comprehending input patterns so that object classes may be predicted.The segmentation process divides the input image into separate segments for a more thorough image study.This study proposes a deep learning-enabled framework for automated document classification,which can be implemented in higher education.To further this goal,a dataset was developed that includes seven categories:Diplomas,Personal documents,Journal of Accounting of higher education diplomas,Service letters,Orders,Production orders,and Student orders.Subsequently,a deep learning model based on Conv2D layers is proposed for the document classification process.In the final part of this research,the proposed model is evaluated and compared with other machine-learning techniques.The results demonstrate that the proposed deep learning model shows high results in document categorization overtaking the other machine learning models by reaching 94.84%,94.79%,94.62%,94.43%,94.07%in accuracy,precision,recall,F-score,and AUC-ROC,respectively.The achieved results prove that the proposed deep model is acceptable to use in practice as an assistant to an office worker.

Normalized glandular dose coefficients for digital breast tomosynthesis using detailed Chinese breast models

The rise in breast cancer diagnoses among Chinese women has necessitated the use of X-ray breast screening,which carries a radiation risk.This study aimed to provide a dosimetry protocol for the Chinese female population to replace the traditional standard that utilizes simplified breast models,for the accurate estimation of the mean glandular dose of a patient undergoing digital breast tomosynthesis(DBT).The first set of detailed Chinese female breast models and representative breast parameters was constructed.Considering backscatter radiation and computational efficiency,we improved the combination of these models and the Chinese reference adult female whole-body voxel phantom.Image acquisition for four commercial DBT systems that are widely employed in China was simulated using the Monte Carlo method to obtain the normalized glandular dose coefficients of DBT(D_(gN)^(DBT))and the glandular depth dose(D_(g)^(dep)(z))for different breast characteristics and X-ray spectra.We calculated a series of D_(gN)^(DBT) values for breasts with different percentage mass glandularities(5%,25%,50%,75%,and 100%)and compressed breast thicknesses(2,3,4,5,6,and 7 cm)at various tube potentials(25,28,30,32,35,and 49 kV)and target/filter combinations(W/Rh,W/Al,Mo/Mo,Rh/Rh,and Rh/Ag).The parameter dependence of the breast characteristics and beam conditions on D_(gN)^(DBT) in detailed breast models was investigated.The D_(gN)^(DBT) results were 14.6-51.0%lower than those of the traditional dosimetry standard in China.The difference in D_(gN)^(DBT) was mainly due to a decrease in the depth of the main energy deposition area caused by the glandular distribution along the depth direction.The results obtained in this study may be used to improve breast dosimetry in China and provide more detailed information on risk assessment during DBT.

Digital Payment Systems in Urban Media Landscapes:The Evolution and Impact of Apple Pay on Urban Life and Consumer Behavior

This study examines the transformative impact of Apple Pay on urban landscapes and socioeconomic frameworks,with a particular focus on spending patterns and retail dynamics in metropolitan areas.By evaluating the adoption levels,the technological support,and the social impact of Apple Pay,the study shows that the service is both a catalyst for the development of digital payment and a sign of an increasing social gap.Although it has rapidly transformed Retail Enterprises and supported the construction of smart cities,especially in major world cities such as New York,London,and Tokyo,the work has brought out notable digital divides.Although Apple Pay,with more than 75%of iPhone users and 9,000 banks in 60 world areas and regions,has impacts that are not the same across urban populations,the study shows that while large format retailers have effectively adopted Apple Pay for value-added services to consumers and enhanced payment efficiency,small businesses encounter significant barriers in implementation.Additionally,the technology leverages smartphone usage and banking relationships,which does not address considerable urban population demographics and deeper issues of technology exclusion and inequality in the contemporary city.Such results call for attaining a just society’s technological advancement for efficiencies while still catering to all groups of urban dwellers.

Study on the Fluid-Solid Coupling Seepage of the Deep Tight Reservoir Based on 3D Digital Core Modeling

Deep tight reservoirs exhibit complex stress and seepage fields due to varying pore structures,thus the seepage characteristics are significant for enhancing oil production.This study conducted triaxial compression and permeability tests to investigate the mechanical and seepage properties of tight sandstone.A digital core of tight sandstone was built using Computed Tomography(CT)scanning,which was divided into matrix and pore phases by a pore equivalent diameter threshold.A fluid-solid coupling model was established to investigate the seepage characteristics at micro-scale.The results showed that increasing the confining pressure decreased porosity,permeability,and flow velocity,with the pore phase becoming the dominant seepage channel.Cracks and large pores closed first under increasing pressure,resulted in a steep drop in permeability.However,permeability slightly decreased under high confining pressure,which followed a first-order exponential function.Flow velocity increased with seepage pressure.And the damage mainly occurred in stress-concentration regions under low seepage pressure.Seepage behavior followed linear Darcy flow,the damage emerged at seepage entrances under high pressure,which decreased rock elastic modulus and significantly increased permeability.

Digital Economy and Corporate Innovation-Washing--An Empirical Study on How Information Mitigates Policy Distortion

As stated in the Report to the 20th National Congress of the Communist Party of China(CPC),innovation remains at the heart of China’s modernization drive,and it is vital to optimize the allocation of innovation resources,deepen structural scientific and technological reforms,and enhance the overall performance of China’s innovation system.Government incentives have boosted firm R&D and innovation efforts;however,they have also triggered an innovation dilemma where enterprises,capitalizing on their informational advantages,resort to innovation-washing behaviors that undermine the intended purpose of the policies.Based on the information asymmetry theory,this paper conducts an empirical study on how the digital economy affects firms’innovation-washing behavior.The development of the regional digital economy could suppress firm innovation-washing behavior in the region,and such a mitigation effect is primarily caused by an increase in the number of digital industry professionals.According to our heterogeneity analysis,the digital economy has a greater impact on firm innovation-washing behavior for certain types of enterprises,including non-state-owned enterprises(non-SOEs),small and medium-sized enterprises(SMEs),enterprises in less competitive industries,and enterprises in unfavorable business environments.Our mechanism analysis revealed that the digital economy may restrain innovation-washing behavior by reducing information asymmetry between enterprises and external stakeholders.In terms of economic outcomes,the digital economy has the potential to directly influence firm innovation output while also indirectly mitigating the subsequent decline in innovation output by discouraging innovation-washing.This paper enriches the research findings on how the digital economy breaks down“information silos”and offers a potential solution to the“emphasis on input and quantity over quality and efficiency”phenomenon in science and technology innovation practices.

Side-channel free quantum digital signature with source monitoring

Quantum digital signature(QDS)can guarantee the information-theoretical security of a signature with the fundamental laws of quantum physics.However,most current QDS protocols do not take source security into account,leading to an overestimation of the signature rate.In this paper,we propose to utilize Hong–Ou–Mandel interference to characterize the upper bound of the source imperfections,and further to quantify information leakage from potential side-channels.Additionally,we combine decoy-state methods and finite-size analysis in analyzing the signature rate.Simulation results demonstrate the performance and feasibility of our approach.Our current work can improve the practical security of QDS systems,thereby promoting their further networked applications.

Influencing Factors of Cultivated Land Fragmentation on Planting Decision of Daylily

Based on questionnaire survey data of daylily planting farmers in the paper,from the perspective of farmers own conditions(including age,gender,education level,and annual household income),climate perception ability,policy perception ability,and land fragmentation situation,consistency analysis,variance analysis,regression analysis and other methods were used to analyze the impact of land use on farmers decision-making changes in planting daylily.The results showed that the age of the household head,annual household income,policy perception ability,and average cultivated land area per block had a significant impact on the planting area of daylily,and the degree of impact increased in order.This study can provide theoretical basis and practical guidance for farmers decision-making and land use methods in planting daylily.

Spatial Pattern and Influencing Factors of China’s Digital Trade Resilience under the Impact of Trade Frictions

In the era of the digital economy,digital trade has demonstrated strong vitality,becoming a crucial driving force for the highquality development of national and regional economies.However,understanding the resilience of digital trade in the face of external crises is an important topic.Taking the backdrop of Sino-US trade friction,this paper constructs a resilience index system for digital trade.It utilizes entropy method,kernel density estimation,and ArcGIS mapping to calculate and visually analyze the resilience of China’s digital trade from 2017 to 2021.Additionally,a Tobit model is constructed to explore the main influencing factors of digital trade resilience patterns.The research findings indicate:1)temporally,during the period of Sino-US trade friction,China’s digital trade resilience shows an overall upward trend,but there are regional differences in resilience levels across the country,with a severe polarization phenomenon.2)Spatially,high resilience is observed in the eastern and central regions of China,while the western and northeastern regions exhibit low resilience.3)From a dimensional perspective,the resistance of digital trade resilience displays a spatial distribution of high values in the east and low values in the west.The recovery force is aggregated along coastal areas,and the renewal force tends to aggregate along the eastern coastline.4)Factors such as economic scale,industrial structure,urbanization rate,government fiscal expenditure,and technological talents significantly promote the enhancement of digital trade resilience.This study reveals the dynamic characteristics and influencing factors of digital trade resilience in responding to external shocks,providing theoretical basis and policy suggestions for enhancing digital trade resilience,and promoting high-quality economic development in China.

Survey and Recommendations for Land Use of Agricultural Machinery Service Organization Facilities in Guizhou Province

With the advancement of agricultural modernization, agricultural machinery service organizations, as an important part of the rural operating entities, show an increasing trend year by year, and need new facilities land in the process of development and growth. Based on the written survey of 597 agricultural machinery service organizations in Guizhou Province, the demand and demand gap of various facilities land use in agricultural machinery service organizations were analyzed and compared. In addition, based on the field survey and policy background, the main practices and experiences of agricultural machinery service organizations in Guizhou Province in the approval and use of facility land were sorted out, and the problems and causes of large gap in facility agricultural land, lack of standards and difficulty in policy implementation were analyzed. Finally, it recommended that the site selection of agricultural machinery service organization facilities needs to be standardized, the land demand needs to be coordinated, the land scale needs to be scientifically demonstrated, and financial support should be sought to promote Guizhou agricultural machinery service organization to become bigger, better and stronger.

Effectiveness of RESET care program: A real-world-evidence on managing non-alcoholic fatty liver disease through digital health interventions

BACKGROUND Non-alcoholic fatty liver disease(NAFLD)management requires sustainable lifestyle modifications.This study aimed to evaluate the effectiveness of the RESET care plan,a comprehensive program that is an integrated personalized diet,exercise,and cognitive behavior therapy,delivered via MyTatva’s digital health application enabled through a body composition analyzer(BCA)and smartwatch.AIM To evaluates the effectiveness of the comprehensive program delivered via My-Tatva’s digital health app enabled through internet of thing devices.METHODS This retrospective observational study analyzed deidentified data from 22 par-ticipants enrolled in the MyTatva RESET care program.Participants were divided into three groups:Group A,diet plan;Group B,diet+exercise plan;and Group C,diet+exercise+cognitive behavioral therapy plan.Participants were provided with a BCA and smartwatch for continuous monitoring of anthropometric para-meters.Statistical analysis,including one-way ANOVA and post-hoc Tukey’s Honest Significant Difference test,was conducted to compare mean changes in anthropometric parameters across the groups.INTRODUCTION Non-alcoholic fatty liver disease(NAFLD)has emerged as a global health burden,affecting approximately 1 in 4 in-dividuals worldwide.NAFLD ranges from simple steatosis(fat accumulation)to non-alcoholic steatohepatitis(NASH),and its global prevalence in the general population is estimated between 6.3%and 33%,with NASH affecting 3-5%[1,2].Obesity is a major risk factor of NAFLD,with studies showing that the likelihood of developing NAFLD increases 5-fold at a body mass index(BMI)of 30-32.5 kg/m²and up to 14-fold at BMI of 37.5-40 kg/m²compared to a BMI of 20-22.5 kg/m²[3,4].Effective NAFLD management requires both dietary and physical activity modifications.Healthy weight loss with sustained muscle mass plays a pivotal role,with a reduction of 3%-5%decreasing hepatic steatosis,5%-7%improving NASH conditions,and 10%or more needed to reverse hepatic fibrosis[5].Management also normalizes elevated liver enzymes(aspartate aminotransferase and alanine aminotransferase),enhances insulin sensitivity,and thereby reduces cardiovascular risk by improving endothelial function and increasing cardiorespiratory fitness[6].However,diet or exercise alone is often not as effective as a combined approach.Integrating both balanced dietary changes and increased physical activity yields more sustainable improvements in NAFLD and overall metabolic health[1,7].Traditional intervention methods usually involve in-person consultations,which often lack real-time and continuous patient monitoring.The recommendation of drastic changes in diet and exercise can also be overwhelming for patients,leading to low adherence rates.Many patients struggle to maintain these changes in the long-term due to a lack of con-tinuous motivational support[8,9].In recent years,the health ecosystem has witnessed a significant shift toward digital health platforms,which complement pharmacological treatments in chronic disease management,and increase scala-bility.These platforms provide continuous monitoring and personalized support,helping to bridge the gap between health care setups and patients[10].Recent digital advances enable internet of things(IoT)devices to be integrated into such management plans to track health metrics,to address the limitations of traditional methods[11,12].The MyTatva digital health application offers the RESET plan,a novel comprehensive approach for NAFLD mana-gement by integrating personalized support from nutrition,physiotherapy,and cognitive behavioral therapy(CBT)coaches.We aimed to evaluate the effectiveness of the RESET plan by analyzing the reduction in anthropometric para-meters across three different digital intervention groups.

Land use/cover change and ecological network in Gansu Province,China during 2000-2020 and their simulations in 2050

Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.

Assessment of ecological geological vulnerability in Mu Us Sandy Land based on GIS and suggestions of ecological protection and restoration

Eco-geological vulnerability assessment is a significant research topic within the field of eco-geology,but it remains poorly studied.The Mu Us Sandy Land,located in the central part of the farming-pastoral ecotone in northern China,plays a critical role in maintaining the ecological security pattern in this region.However,this sandy land also faces severe sandy desertification and ecological degradation.This study conducted a regional eco-geological vulnerability assessment of the Mu Us Sandy Land using a comprehensive index evaluation method based on eco-geological theories and survey results.To construct an appropriate index system for the eco-geological vulnerability assessment of the Mu Us Sandy Land,the study considered the sandy land’s unique characteristics and identified 15 factors of five categories,namely geology,meteorology,soil,topography,and vegetation.The paper calculated the comprehensive weights of all the indices using the analytic hierarchy process(AHP)and the entropy weight method(EWM).Furthermore,it established the eco-geological vulnerability index(EGVI)and obtained the assessment results.The results showed that the eco-geological vulnerability of the Mu Us Sandy Land gradually intensifies from east to west,manifested as vulnerable eco-geological conditions overall.Specifically,extremely vulnerable zones are found in the northwestern and southeastern parts of the study area,highly vulnerable zones in the western and southern parts,moderately vulnerable zones in the central part,and slightly and potentially vulnerable zones in the eastern and southern parts.Areas with high spatial autocorrelations include the northern Uxin Banner-Otog Banner-Angsu Town area,the surrounding areas of Hongdunjie Town in the southeastern part of the study area,the Hongshiqiao Township-Xiaohaotu Township area,Otog Front Banner,and Bainijing Town,which should be prioritized in the ecological conservation and restoration.Additionally,the paper proposed suggestions for the ecological conservation and restoration of county-level administrative areas in the study area.Overall,the findings provide a valuable reference for the ecological conservation and restoration of the Mu Us Sandy Land and other desert areas in arid and semi-arid regions.

基于Landsat数据的江苏省土地利用变化分析

随着人类社会生活的不断演变,土地利用模式和土地使用形态随之发生根本性变化。文章以江苏省为例,通过土地利用动态度、土地利用转移矩阵等方法,深入研究江苏省土地利用特征的时空变化情况。研究发现,江苏省耕地、未利用土地面积减少趋势明显,大部分转向建设用地和坑塘、滩地等用途,草地面积明显增加。这表明江苏省在加速城市化步伐的过程中,同步增强了对生态文明建设的重视。文章为江苏省国土空间规划、可持续发展路径的探索以及经济生态的协调发展贡献了多元化的思考维度。

基于谷歌地球引擎和Landsat影像的广西壮族自治区土地覆盖变化及驱动因素研究

基于GEE和随机森林分类算法研究广西壮族自治区在1995—2022年27 a间的土地覆被变化,采用地理探测器对不同土地覆被类型的时空变化及其主要驱动因素进行分析研究。结果表明:1)土地覆被类型分类结果具有较好的分类精度,整体精度在87%~92%。2)1995—2022年,广西壮族自治区的林地和建设用地面积持续增加,增幅分别达75.94%和132.67%。林地面积从85382.72 km^(2)增加到150224.55 km^(2),建设用地面积从2038.73 km^(2)增加到4743.46 km^(2);与此同时,草地及稀疏灌草混交地面积减少了82.46%(66990.97 km^(2));其他土地覆被类型变化则相对稳定。3)通过地理探测器模型的分析结果显示,人为因素是影响土地利用/覆被(LULC)变化的主要驱动因素,经济的快速发展、城市人口的增加和工业扩张是建设用地和林地扩张以及植被减少的主要原因。研究结果对于广西壮族自治区的生态环境管理和土地可持续利用规划具有参考价值。

基于Landsat影像的城市土地利用动态监测

土地是自然界不可或缺的资源,土地利用反映了人地关系。随着人口数量的持续增加和社会工业化、城市化的持续推进,如何科学地开发利用宝贵的土地资源越来越受到人们的重视。本文通过2013年和2023年的Landsat影像数据,结合遥感与GIS,对10年间合肥市土地资源进行监测与分析,结果表明,经过10年的城市发展,合肥市耕地面积减少了65707.92 hm 2,建设用地增长了39181.05 hm 2,林地减少了1728.27 hm 2,水域增加了28255.14 hm 2。

Digitized Outcrop Geomodeling of Ramp Shoals and its Reservoirs： as an Example of Lower Triassic Feixianguan Formation of Eastern Sichuan Basin

Numerous hydrocarbon accumulations are found in ramp crest shoals worldwide and therefore this depositional setting has a high potential of being the hydrocarbon reservoir. In this paper, we combined digital outcrop geology and traditional geological mapping to build an outcrop-based geocellular model of the ramp-crest shoal complex of the Lower Triassic Feixianguan Formation in the Eastern Sichuan Basin. The outcrop model serves as an analogue for the subsurface reservoir of the Feixianguan Formation and illustrates the complexity of the lithofacies types, stratigraphic architecture, and reservoir heterogeneities at a scale below conventional subsurface data resolution. The studied ramp -crest shoal complex consists of thirteen types of lithofacies that can be grouped into three facies-groups corresponding to subtidal intraclastic shoal, sub- to inter-tidal oolitic shoal, and tidal flat depositional environments respectively. The stratigraphic architecture of the shoal complex shows mostly a strong progradation of the high energy facies associated with an overall decrease of accommodation space associated with relative sea level still stand. Two reservoir facies associations have been recognized. The first one consists of supratidai dolomudstone and upper intertidal partially dolomitized oolitic packstone with anhydrite or nodules. These facies were deposited above the high energy oolitic grainstones and occurs as thin-bedded and laterally continuous layers, characterized by high porosity and low permeability. The second reservoir facies association is composed of intertidal crystalline dolomite and subtidal intraclastic bindstone that occurs stratigraphically below the oolitic grainstones. These deposits consist of massive laterally discontinuously beds, and are characterized by high porosity and high permeability. Both types of reservoir facies tend to be stacked vertically and migrated laterally with the progradation of the shoal complex. The construction of the outcrop-based 3D geological model provide a description and quantification of the facies distribution within a robust stratigraphic framework and the style and amount of reservoir heterogeneities associated with a ramp-crest shoal complex reservoir such as the one found in Lower Triassic Feixianguan Formation and Cambrian Longwangmiao Formation in Sichuan Basin or other ramp-crest reservoir worldwide.

Digital Problems and Strategies of Partial Revision in Overall Plan of Land Use

The technical route of partial revision in overall plan of land use is briefly described.It is pointed out that problems of area measuring in the technical route are mainly due to the digital process.The digital problems of partial revision in overall plan of land use are presented as follows:the maps are not proofread before digitalization;the coordinate matching and projection transformation are not conducted on the maps;the information is asymmetrical pre and post the digitalization;the location lacks precision;the result maps are substandard.The causes of these problems are analyzed,which cover the following aspects.The lack of united management regulations;uneven working abilities of the staff in the compilation units;unawareness of the importance of map digilalization;poor basic conclitions of the original plan maps.At last,the relevant suggestions are put forward,for instance,releasing the national united management methods and technical criteria,establishing industrial admittance system and qualification system of complication units,setting up the mechanism of supervising digitalized results and controlling the quality,conducting coordinate matching and projection transformation and unifying the specification and mode of the results of maps so as to provide technical support for the overall plan of land use,play the micro-regulating role of land use and take a leading role in the sustainable development of social economy.

Monitoring Land Use Dynamics in Chanthaburi Province of Thailand Using Digital Remotely Sensed Images

A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning System) and ancillary data were combined by the method which adopts the main idea of classifying images by steps from decision tree method and the hybridized supervised and unsupervised classification. An integration of automatic image interpretation, ancillary materials and expert knowledge was realized. Two subscenes of Landsat 5 Thematic Mapper (TM) images of bands 3, 4 and 5 obtained on December 15, 1992, and January 17, 1999, were used for image processing and spatial data analysis in the study. The overall accuracy of the results of classification reached 90%, which was verified by field check.Results showed that shrimp farm land, urban and traffic land, barren land, bush and agricultural developing area increased in area, mangrove, paddy field, swamp and marsh land, orchard and plantation, and tropical grass land decreased, and the forest land kept almost stable. Ecological analysis on the land use changes showed that more attentions should be paid on the effect of land development on ecological environment in the future land planning and management.

Re-delineating mountainous areas with three topographic parameters in Mainland Southeast Asia using ASTER global digital elevation model data

Tropical mountainous areas not only provide substantial carbon storage and play an important role in global biological diversity, but also provide basic livelihood for a large number of poor ethnic minorities. However, there is no unified and explicit definition for mountainous areas. The local elevation range(LER) is a crucial structural parameter for delineating mountainous areas. However, current LER products are limited by the subjective selection of an optimum statistical window or coarser spatial resolution of topographical data. In this study, we presented an approach using thresholds for three topographic parameters, elevation, slope, and LER, derived from the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model(ASTER GDEM) to redelineate the vast mountainous areas of mainland Southeast Asia(MSEA). The mean change-point analysis method was applied to determine the optimum statistical window of the 1 arc second(approximately 30 m)-resolution GDEM LER. The results showed that: First, the optimum statistical window is 38 × 38 cell units(width × height) in a rectangular neighborhood, or an area of about 1.30 km^2 for calculating GDEM LER in MSEA. Second, the LER of more than 80% of the area ranges from 30 m to 499 m in MSEA. The LERs in the northern and northwestern MSEA are greater than their counterparts in the south and east. Third, the area of the re-delineated mountainous areas was 83.52 × 10~4 km^2, about 38.71% of the total area. Spatially, the mountainous areas are mainly distributed in the north and northeast of MSEA. The re-delineated 30-m resolution map of the mountainous areas will serve as a topographical dataset for monitoring mountainrelated land surface changes in MSEA. The parameter-modified mountain extraction procedure can be expanded to delineate global mountainous areas.