Footprint Algorithms Research Articles

基于改进生态足迹模型的可持续发展评价——以北疆为例

PDF HTML阅读 XML下载 导出引用 引用提醒 基于改进生态足迹模型的可持续发展评价——以北疆为例 DOI: 10.5846/stxb202112203605 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（2020D04003） Sustainable development evaluation based on an improved ecological footprint model: a case study of northern Xinjiang Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生态足迹评价体系，可以在一定程度上刻画区域社会经济发展对当地生态环境产生的影响，当前可持续发展研究的难点之一，便是如何更加真实的体现这种影响。立足于传统生态足迹模型，采用"一年一区一值"的参数方案计算区域当年均衡因子与产量因子，结合土地利用转移矩阵和建设用地流入量改进建设用地足迹算法，对北疆地区2005年、2010年、2015年、2018年生态足迹及生态承载力进行测度，并结合相关指数对研究区发展的可持续性进行评价。结果表明：①北疆生态足迹增涨3.5倍，且以能源增长为主导，生物生产性足迹贡献率大幅下降；人均生态足迹增长3.4倍，工业型城市生态足迹增长率及人均生态足迹增长率均高于其他类型城市。②研究区生态承载力呈现上升态势，除水域和草地外，其他地类承载力均呈上升态势，昌吉州与阿勒泰地区的总体承载力及人均承载力均呈下降态势。③北疆生态利用效率上涨1.32倍，各行政单元呈现农业及服务业型城市生态利用效率上升、工业型城市生态利用效率降低的态势，表明工业型城市生态足迹增速远高于经济增速。④各行政单元呈现生态赤字状态且不断加剧，总体及人均增速都呈现工业型 > 农业型 > 服务业型城市。整体而言，研究区系统安全性一般，处于协调发展状态，但存在由生态足迹激增引发安全性下降的风险，部分地州呈低协调甚至不协调状态，整体可持续发展性有所降低。 Abstract:Ecological footprint is a biologically productive land that can produce the materials needed to meet the productive needs of human life and absorb the waste generated by humans in the region. Ecological footprint evaluation system can describe the impact of regional social and economic development on local ecological environment to a certain extent, but one of the difficulties in current sustainable development research is how to more truly reflect such impact. Based on traditionally ecological footprint model, this study firstly calculates the equilibrium factor and yield factor by year and by subregion. We improved the construction land footprint algorithm through combining the land use transfer matrix. Finally measured the ecological footprint and ecological carrying capacity of Northern Xinjiang in 2005, 2010, 2015 and 2018, and evaluated the sustainability of development in the study area. The results showed that:(1) the ecological footprint of the Northern Xinjiang increased by 3.5 times, which was dominated by energy footprint, while the contribution of biological productivity footprint decreased significantly. Per capita ecological footprint increased by 3.4 times, and the growth rate of ecological footprint and per capita ecological footprint of industrial cities were both higher than other types of cities. (2) The ecological carrying capacity of the study area showed an upward trend except for water and grassland. The overall and per capita carrying capacity of Changji and Altay were both declining. (3) The ecological efficiency of Northern Xinjiang increased by 1.32 times. The units showed a trend of increasing ecological efficiency in agricultural and service-oriented cities and decreasing in industrial cities, indicated that the growth rate of ecological footprint of industrial cities was higher than the corresponding cities' economy. (4) The ecological deficit of each unit was increased, and the growth rate of overall and per capita showed a trend of industrial cities > agricultural cities > service-oriented cities. Overall, ecosystem security in the study area was at an average level, and the ecological system and economic system were in a coupling state. But there was a risk of security decline caused by the surge of ecological footprint. Some cities were in a low coupling or even decoupling state, and the overall sustainability was reduced. Therefore, in the future development process, government should combine national and regional policy guidance with our own geographic and resource advantages, actively optimize the industrial structure, improve the efficiency of resource utilization, to build a diversified, healthy and sustainable new development system. 参考文献 相似文献 引证文献

Upscaling Methane Flux From Plot Level to Eddy Covariance Tower Domains in Five Alaskan Tundra Ecosystems

Spatial heterogeneity in methane (CH4) flux requires a reliable upscaling approach to reach accurate regional CH4 budgets in the Arctic tundra. In this study, we combined the CLM-Microbe model with three footprint algorithms to scale up CH4 flux from a plot level to eddy covariance (EC) tower domains (200 m × 200 m) in the Alaska North Slope, for three sites in Utqiaġvik (US-Beo, US-Bes, and US-Brw), one in Atqasuk (US-Atq) and one in Ivotuk (US-Ivo), for a period of 2013–2015. Three footprint algorithms were the homogenous footprint (HF) that assumes even contribution of all grid cells, the gradient footprint (GF) that assumes gradually declining contribution from center grid cells to edges, and the dynamic footprint (DF) that considers the impacts of wind and heterogeneity of land surface. Simulated annual CH4 flux was highly consistent with the EC measurements at US-Beo and US-Bes. In contrast, flux was overestimated at US-Brw, US-Atq, and US-Ivo due to the higher simulated CH4 flux in early growing seasons. The simulated monthly CH4 flux was consistent with EC measurements but with different accuracies among footprint algorithms. At US-Bes in September 2013, RMSE and NNSE were 0.002 μmol m−2 s−1 and 0.782 using the DF algorithm, but 0.007 μmol m−2 s−1 and 0.758 using HF and 0.007 μmol m−2 s−1 and 0.765 using GF, respectively. DF algorithm performed better than the HF and GF algorithms in capturing the temporal variation in daily CH4 flux each month, while the model accuracy was similar among the three algorithms due to flat landscapes. Temporal variations in CH4 flux during 2013–2015 were predominately explained by air temperature (67–74%), followed by precipitation (22–36%). Spatial heterogeneities in vegetation fraction and elevation dominated the spatial variations in CH4 flux for all five tower domains despite relatively weak differences in simulated CH4 flux among three footprint algorithms. The CLM-Microbe model can simulate CH4 flux at both plot and landscape scales at a high temporal resolution, which should be applied to other landscapes. Integrating land surface models with an appropriate algorithm provides a powerful tool for upscaling CH4 flux in terrestrial ecosystems.

Phishing and Sybil Enhanced Behavior Processing and Footprint Algorithms in Vehicular Ad Hoc Network

Communication between vehicles is the core of VANETs, which are built on notions of mobile ad hoc networks (MANETs). Each car on the network is now seen as a mobile network node. All participating cars become wireless routers or nodes, depending on your viewpoint. VANET creates a huge network with a long-range by connecting all cars within range to a fixed unit. VANET assists with traffic regulation, communication between vehicles and the sharing of road data. There is a possibility that the VANET network could be compromised by identity and information concerns, resulting in data delays or theft. Attacks like Sybil and phishing are possible because of this network's weakness. Due to the two recent strikes, infrastructure and human lives may be in jeopardy. There are two novel algorithms developed by the authors to tackle Sybil and Phishing assaults on VANET networks: Phishing and Sybil Enhanced Behavior Processing and Footprints (P&SEBP&F). Originally known as the Phishing and Sybil Enhanced Behavior Processing and Footprint, P&STL&T was renamed P&STL&T. Phishing and Sybil were used as well as varied attacker-to-victim node ratios to test the effectiveness of the new tactics for assessing effectiveness. Compared to previous study and the work of the other authors cited, there were approximately 30% fewer attackers detected during the research.

AOI-shapes: An Efficient Footprint Algorithm to Support Visualization of User-defined Urban Areas of Interest

Understanding urban areas of interest (AOIs) is essential in many real-life scenarios, and such AOIs can be computed based on the geographic points that satisfy user queries. In this article, we study the problem of efficient and effective visualization of user-defined urban AOIs in an interactive manner. In particular, we first define the problem of user-defined AOI visualization based on a real estate data visualization scenario, and we illustrate why a novel footprint method is needed to support the visualization. After extensively reviewing existing “footprint” methods, we propose a parameter-free footprint method, named AOI-shapes, to capture the boundary information of a user-defined urban AOI. Next, to allow interactive query refinements by the user, we propose two efficient and scalable algorithms to incrementally generate urban AOIs by reusing existing visualization results. Finally, we conduct extensive experiments with both synthetic and real-world datasets to demonstrate the quality and efficiency of the proposed methods.

Security Measures with Enhanced Behavior Processing and Footprint Algorithm against Sybil and Bogus Attacks in Vehicular Ad Hoc Network.

Vehicular ad hoc networks (VANETs) are created according to the principles of ad hoc mobile networks (MANETs), i.e., spontaneous creation of a wireless network for vehicle-to-vehicle (V2V) communication. Each vehicle in this network is treated as a node that is part of the mobile network. VANET turns all cooperating vehicles into a wireless router or node. This makes it possible to connect all cars within range to a stationary unit and create a wide network with a huge range. VANET is widely used for better traffic management, vehicle-to-vehicle communication, and road information provision. The VANET network is exposed to identity and information attacks, concealing or delaying data transmission, or information theft. Therefore, there are multiple types of attack, such as Sybil or bogus, that might harm the whole network infrastructure. The consequences of the mentioned two attacks could lead not only to the given infrastructure but could cause hammering people’s lives. In this paper, we analyze the ongoing methods for preserving Sybil and bogus attacks in a VANET network together with the authors’ methods: the Bogus & Sybil Trust Level & Timestamp (B&STL&T) algorithm and the Bogus & Sybil Enhanced Behavior Processing & Footprint (B&SEBP&F) algorithm. The first algorithm, the Bogus & Sybil Trust Level & Timestamp (B&STL&T) algorithm was improved into the Bogus & Sybil Enhanced Behavior Processing & Footprint (B&SEBP&F), presented in the paper. The proposed methods were tested with multiple scenarios using different variations of bogus and Sybil attack and various attacker–victim node number ratios. During analysis, it was observed that detection of all attackers in the network was reduced by approximately 30% in comparison to previous work and that of other cited authors.

Detecting Sybil attacks in vehicular ad hoc networks

ABSTRACT Ad hoc networks are vulnerable to numerous attacks due to its infrastructure-less nature, one of these attacks is the Sybil attack. Sybil attack is a severe attack on vehicular ad hoc networks (VANET) in which the intruder maliciously claims or steals multiple identities and uses these identities to disturb the functionality of the VANET network by disseminating false identities. Many solutions have been proposed in order to defend the VANET network against the Sybil attack. In this research a hybrid algorithm is proposed by combining footprint and privacy-preserving detection of abuses of pseudonyms (P2DAP) methods. The hybrid detection algorithm is implemented using the ns2 simulator. The proposed algorithm works as follows. P2DAP acts better than the footprint algorithm when the number of vehicles increases. On the other hand, the footprint algorithm acts better when the speed of vehicles increases. The hybrid algorithm depends on encryption, authentication and on the trajectory of the vehicle. The scenarios will be generated using SUMO and MOVE tools.

Characterizing the shapes of noisy, non-uniform, and disconnected point clusters in the plane

Many spatial analyses involve constructing possibly non-convex polygons, also called “footprints,” that characterize the shape of a set of points in the plane. In cases where the point set contains pronounced clusters and outliers, footprints consisting of disconnected shapes and excluding outliers are desirable. This paper develops and tests a new algorithm for generating such possibly disconnected shapes from clustered points with outliers. The algorithm is called χ-outline, and is based on an extension of the established χ-shape algorithm. The χ-outline algorithm is simple, flexible, and as efficient as the most widely used alternatives, O(nlogn) time complexity. Compared with other footprint algorithms, the χ-outline algorithm requires fewer parameters than two-step clustering-footprint generation and is not limited to simple connected polygons, a limitation of χ-shapes. Further, experimental comparison with leading alternatives demonstrates that χ-outlines match or exceed the accuracy of α-shapes or two-step clustering-footprint generation, and is more robust to some forms of non-uniform point densities. The effectiveness of the algorithm is demonstrated through the case study of recovering the complex and disconnected boundary of a wildfire from crowdsourced wildfire reports.

Footprint Evaluation for Flux and Concentration Measurements for an Urban-Like Canopy with Coupled Lagrangian Stochastic and Large-Eddy Simulation Models

A footprint algorithm, based on a Lagrangian stochastic (LS) model embedded into a parallelized large-eddy simulation (LES) model, is used for the evaluation of flux and concentration footprints of passive scalars in flow in and above an urban-like canopy layer of a neutrally stratified $$440 \hbox { m}$$ deep boundary layer. The urban-like canopy layer is realized by an aligned array of cuboids whose height H is $$40\hbox { m}$$ . The canopy flow involves strong small-scale inhomogeneities although it is homogeneous at the large scale. The source height is $$1\hbox { m}$$ (0.025H) above the ground in the street canyons, roughly mimicking traffic emissions. Footprints are evaluated for four heights from 0.25H to 2.5H, and for up to eight different horizontal sensor positions per measurement height, comprising sensor positions inside as well as outside of the street canyon that extend perpendicular to the mean wind direction. The LES-LS footprints are compared with footprints estimated by a conventional model (Kormann and Meixner, in Boundary-Layer Meteorol 99:207–224, 2001). It becomes evident that the local heterogeneity of the flow has a considerable impact on flux and concentration footprints. As expected, footprints for measurements within and right above the canopy layer show complex and completely different footprint shapes compared to the ellipsoidal shape obtained from conventional footprint models that assume horizontal homogeneity of the turbulent flow as well as the sources of passive scalars. Our results show the importance of street-canyon flow and turbulence for the vertical mixing of scalar concentration.

Massively parallel read mapping on GPUs with the q-group index and PEANUT

We present the q-group index, a novel data structure for read mapping tailored towards graphics processing units (GPUs) with a small memory footprint and efficient parallel algorithms for querying and building. On top of the q-group index we introduce PEANUT, a highly parallel GPU-based read mapper. PEANUT provides the possibility to output both the best hits or all hits of a read. Our benchmarks show that PEANUT outperforms other state-of-the-art read mappers in terms of speed while maintaining or slightly increasing precision, recall and sensitivity. Subjects Bioinformatics, Computational Biology

Finding top-k elements in data streams

Identifying the most frequent elements in a data stream is a well known and difficult problem. Identifying the most frequent elements for each individual, especially in very large populations, is even harder. The use of fast and small memory footprint algorithms is paramount when the number of individuals is very large. In many situations such analysis needs to be performed and kept up to date in near real time. Fortunately, approximate answers are usually adequate when dealing with this problem. This paper presents a new and innovative algorithm that addresses this problem by merging the commonly used counter-based and sketch-based techniques for top-k identification. The algorithm provides the top-k list of elements, their frequency and an error estimate for each frequency value. It also provides strong guarantees on the error estimate, order of elements and inclusion of elements in the list depending on their real frequency. Additionally the algorithm provides stochastic bounds on the error and expected error estimates. Telecommunications customer’s behavior and voice call data is used to present concrete results obtained with this algorithm and to illustrate improvements over previously existing algorithms.

Weak preservation of local neutral substitution rates across mammalian genomes

BackgroundThe rate at which neutral (non-functional) bases undergo substitution is highly dependent on their location within a genome. However, it is not clear how fast these location-dependent rates change, or to what extent the substitution rate patterns are conserved between lineages. To address this question, which is critical not only for understanding the substitution process but also for evaluating phylogenetic footprinting algorithms, we examine ancestral repeats: a predominantly neutral dataset with a significantly higher genomic density than other datasets commonly used to study substitution rate variation. Using this repeat data, we measure the extent to which orthologous ancestral repeat sequences exhibit similar substitution patterns in separate mammalian lineages, allowing us to ascertain how well local substitution rates have been preserved across species.ResultsWe calculated substitution rates for each ancestral repeat in each of three independent mammalian lineages (primate – from human/macaque alignments, rodent – from mouse/rat alignments, and laurasiatheria – from dog/cow alignments). We then measured the correlation of local substitution rates among these lineages. Overall we found the correlations between lineages to be statistically significant, but too weak to have much predictive power (r2 <5%). These correlations were found to be primarily driven by regional effects at the scale of several hundred kb or larger. A few repeat classes (e.g. 7SK, Charlie8, and MER121) also exhibited stronger conservation of rate patterns, likely due to the effect of repeat-specific purifying selection. These classes should be excluded when estimating local neutral substitution rates.ConclusionAlthough local neutral substitution rates have some correlations among mammalian species, these correlations have little predictive power on the scale of individual repeats. This indicates that local substitution rates have changed significantly among the lineages we have studied, and are likely to have changed even more for more diverged lineages. The correlations that do persist are too weak to be responsible for many of the highly conserved elements found by phylogenetic footprinting algorithms, leading us to conclude that such elements must be conserved due to selective forces.

Conserved noncoding sequences among cultivated cereal genomes identify candidate regulatory sequence elements and patterns of promoter evolution.

Surveys for conserved noncoding sequences (CNS) among genes from monocot cereal species were conducted to assess the general properties of CNS in grass genomes and their correlation with known promoter regulatory elements. Initial comparisons of 11 orthologous maize-rice gene pairs found that previously defined regulatory motifs could be identified within short CNS but could not be distinguished reliably from random sequence matches. Among the different phylogenetic footprinting algorithms tested, the VISTA tool yielded the most informative alignments of noncoding sequence. VISTA was used to survey for CNS among all publicly available genomic sequences from maize, rice, wheat, barley, and sorghum, representing >300 gene comparisons. Comparisons of orthologous maize-rice and maize-sorghum gene pairs identified 20 bp as a minimal length criterion for a significant CNS among grass genes, with few such CNS found to be conserved across rice, maize, sorghum, and barley. The frequency and length of cereal CNS as well as nucleotide substitution rates within CNS were consistent with the known phylogenetic distances among the species compared. The implications of these findings for the evolution of cereal gene promoter sequences and the utility of using the nearly completed rice genome sequence to predict candidate regulatory elements in other cereal genes by phylogenetic footprinting are discussed.