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    Journal of East China Normal University(Natural Science)    2023, 2023 (6): 0-x.  
    Abstract91)   HTML13)    PDF (365KB)(794)      
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    A scheme of vegetation classification system at city scale and its application in Shanghai
    Liangjun DA, Zhiwen GAO, Yongchuan YANG, Kun SONG, Xueyan GUO, Hong LIANG, Tiyuan XIA, Huafeng WANG, Ting ZHOU, Daigui ZHANG, Zhihui TIAN, Yuandong HU, Bo JIA
    Journal of East China Normal University(Natural Science)    2023, 2023 (3): 1-8.   DOI: 10.3969/j.issn.1000-5641.2023.03.001
    Abstract219)   HTML240)    PDF (574KB)(218)      

    The development of city-scale vegetation maps is helpful for vegetation management and conservation. Vegetation classification systems in China mainly consider natural vegetation and most classification systems operate at the national or provincial scale, making them unsuitable for city-scale classification. Until now, the lack of a classification system designed specifically for urban vegetation has limited the studies on urban vegetation. Based on the origin, disturbance, and function, our classification system divides urban vegetation into natural, secondary, and cultivated vegetations. Based on the function, cultivated vegetation is further divided into artificial forest land, landscape green land , and urban agricultural vegetations. Based on the Classification System of China’s Vegetation in 1980 and the three newly proposed preliminary guideline documents for classification of natural vegetation, we establish a new urban vegetation classification system. We applied the principles of this new urban system in Shanghai and other areas in China, to further refine the system and ensure it has both academic and practical values. This work provides the theoretical basis for compiling information about urban vegetation and provides technical support for the recognition, protection, construction, and management of urban vegetation.

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    Multimodal-based prediction model for acute kidney injury
    Wei DENG, Fang ZHOU
    Journal of East China Normal University(Natural Science)    2023, 2023 (4): 52-64.   DOI: 10.3969/j.issn.1000-5641.2023.04.006
    Abstract158)   HTML12)    PDF (1179KB)(193)      

    Acute kidney injury is a clinical disease with a high morbidity rate, and early identification of potential patients can facilitate medical interventions to reduce morbidity and mortality. In recent years, electronic health records have been widely used to predict an individual’s potential risk. Most of the existing acute kidney injury prediction models tackle the issue of sparsity and irregularity in the physiological variables data by aggregating data or imputing the missing value, but ignore the patient’s health status implied by the missing information. Moreover, they do not consider the characteristics of and correlation between the various modalities. To solve the above issues, we present a multi-modal disease prediction model for acute kidney injury. The proposed model considers a variety of modal data, including physiological variables, disease, and demographic data. A new mask and time span based long short term memory (LSTM) network is designed to learn the time span and missing information of individual Physiological variables, and furthermore, to capture their numerical changes and frequency changes. The multi-head self-attention mechanism is introduced to promote interaction learning of each modality representation. Experiments on the real-world application of acute kidney injury risk prediction and mortality risk prediction demonstrate the effectiveness and rationality of the proposed model.

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    Disinfection effect of seven frequently used disinfectants on bacteriophage MS2
    Yu LI, Zhenming GE
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 161-167.   DOI: 10.3969/j.issn.1000-5641.2023.02.017
    Abstract288)   HTML13)    PDF (1485KB)(183)      

    In this study, the MS2 phages were used as an indicator microorganism to test the function of seven disinfectants with different components: hydrogen peroxide, ethanol, fermented lactic acid disinfectant, iodine disinfectant, quaternary ammonium disinfectant, chlorine-containing disinfectant, and peracetic acid disinfectant. Our results showed that the virus disinfection rate varied notably between the selected disinfectants. The iodine disinfectant exhibited the strongest disinfection effect, followed by the quaternary ammonium salt disinfectant and the peracetic acid disinfectant, while the disinfection effects of hydrogen peroxide, ethanol, and fermentation lactic acid disinfectant were inadequate. The test results provide a reference for the efficient utilization of various disinfectants to eliminate harmful microorganisms in the environment.

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    Assessment of land use exposure to coastal erosion in the delta region and its implications on spatial planning: An example from the Pudong New Area of Shanghai
    Xiaoting WANG, Hualong LUAN, Weiguo ZHANG, Nina Siu-Ngan LAM
    Journal of East China Normal University(Natural Science)    2023, 2023 (3): 181-193.   DOI: 10.3969/j.issn.1000-5641.2023.03.018
    Abstract125)   HTML16)    PDF (2164KB)(168)      

    In the context of rising sea-levels under global warming and fluvial sediment load decline, the risk of coastal erosion is increasing in global deltas. Evaluating the delta morphological change and its vulnerability to erosion in the future and analyzing land use exposure to coastal erosion, is of great significance for spatial planning, disaster prevention and mitigation, and the sustainable development of coastal regions. In this study, Pudong New Area of Shanghai, which is located in the Yangtze River Delta, was selected to compare its coastal erosion vulnerability in 2016 and 2035 using bathymetry of 2016 and modelled bathymetry of 2035 under a scenario of fluvial sediment load of 125 Mt/a and a cumulative sea-level rise of 16.5 cm. A comparison of land use exposure is made between the pattern in 2019 and the pattern projected for 2035 by the government. The results show that the spatial pattern of coastal erosion vulnerability is controlled by the morphological evolution of the delta over the last 1000 years. Coastal sections with high and very high categories of land use exposure and erosion vulnerability in the recent past (2016—2019) total 32.3 km in length, which accounts for 31.1% of the coast of the Pudong New Area. These figures are projected to be 47.5 km and 45.8%, respectively, in 2035, under the condition of reduced fluvial sediment load and planned land usage. In 2035, coastal sections along the Pudong Airport and Luchaogang will face an increase of erosion vulnerability category. According to the current plan, these two sections also show an increase in land use exposure due to airport expansion and new city development. The results suggest that these sections require erosion monitoring and erosion management during implementation of the plan. The methods used in this study can provide references for exposure assessment of coastal erosion and the formulation of territorial planning in coastal regions elsewhere.

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    LaSalle’s invariance principle for delay differential equations driven by α-stable processes
    Zhenzhong ZHANG, Xu CHEN, Jinying TONG
    Journal of East China Normal University(Natural Science)    2023, 2023 (4): 11-23.   DOI: 10.3969/j.issn.1000-5641.2023.04.002
    Abstract120)   HTML6)    PDF (696KB)(161)      

    LaSalle’s invariance principle is an important tool for studying the stability of stochastic systems. Considering the influence of time delay and pure-jump path on the stability of the system and using the convergence theorem for special semi-martingale, the LaSalle’s invariance principle for a class of stochastic delay differential equations driven by $\alpha$ -stable processes is established in this study. The sufficient conditions for the asymptotic stability of a class of delay equations are given by LaSalle’s invariance principle.

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    Research on travel time prediction based on neural network
    Zhaoyang WU, Jiali MAO
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 106-118.   DOI: 10.3969/j.issn.1000-5641.2023.02.012
    Abstract235)   HTML8)    PDF (1993KB)(160)      

    The popularity of positioning devices has generated a large volume of vehicle driving data, making it possible to use historical data to predict the driving time of vehicles. Vehicle driving data consists of two parts: the sequence of road segments that the vehicle travels through, the departure time, the total length of the path, and other external information. The questions of how to extract sequence features in road segments and how to effectively fuse sequence features with external features become the key issues in predicting the travel time. To solve the aforementioned problems, a transformer-based travel time prediction model is proposed, which consists of two parts: a road segment sequence processing module and a feature fusion module. First, the road segment sequence processing module uses the self-attention mechanism to process the road segment sequence and extract the road segment sequence features. The model can not only fully consider the spatiotemporal correlation of road speeds between each road segment and other road segments, but also ensures the parallel input of data into the model, avoiding the low efficiency problem caused by sequential input of data when using recurrent neural networks. The feature fusion module fuses the road segment sequence features with external information, such as departure time, and obtains the predicted travel time. On this basis, the number of road segments connected by the intersection is determined by the upstream and downstream intersection features of the road segment, and the input model is combined with the road segment characteristics to further improve the prediction accuracy of the driving time. Comparative experiments with mainstream prediction methods on real data sets show that the model improves prediction accuracy and training speed, reflecting the effectiveness of the proposed method.

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    Computational study on strain-induced transition of Fe2CrGe from an antiferromagnetic ground state to a ferromagnetic half-metal state
    Jin GUO, Xiao HU, Wenhui XIE
    Journal of East China Normal University(Natural Science)    2023, 2023 (4): 65-73.   DOI: 10.3969/j.issn.1000-5641.2023.04.007
    Abstract108)   HTML7)    PDF (1097KB)(131)      

    In this study, the electronic structure and magnetism of the Heusler alloy Fe2CrGe are investigated using first-principle calculations. Results show that the ground state of Fe2CrGe is antiferromagnetic metal in which Fe ion and Cr ion are in low- and high-spin states of $ S=0 $ and $ S=1 $ , respectively. The energy of the antiferromagnetic state is approximately 0.103 eV less than that of the ferromagnetic state. In addition, when a tetragonal strain is applied to Fe2CrGe, a transition from antiferromagnetic to ferromagnetic material occurs at +1.7% and –1.7% strains, and Fe2CrGe becomes a ferromagnetic half-metal. A half-metal energy gap of approximately 0.2 eV occurs when the strain reaches ±5%. The Curie temperature of Fe2CrGe is estimated to be 393 K, which is much higher than room temperature, indicating that Fe2CrGe may be a potential candidate for spintronic applications.

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    Time series database query optimization for anomaly detection
    Shuai ZHANG, Huiqi HU, Yaoqiang XU, Xuan ZHOU
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 119-131.   DOI: 10.3969/j.issn.1000-5641.2023.02.013
    Abstract292)   HTML15)    PDF (2279KB)(130)      

    With the development of the Internet of Things, a large number of sensor devices can be connected to a network. Anomaly detection of data generated by these devices is related to the stability of system services. A time series database is a database system optimized for time series data. As an important component of a monitoring system, time series databases are responsible for storing and querying continuous streams of time series data. The current time series database, however, cannot fully utilize system computing resources and cannot meet the latency requirements when coping with queries from multiple data sources. To address these drawbacks, we redesigned the query execution model of a time series database based on the well-known InfluxDB, and we proposed InfluxDB-PP (parallel processing) as a method to address the aforementioned problems. The experimental results show that InfluxDB-PP reduces query latency by about 85.7% compared to InfluxDB for real-time anomaly data query scenarios.

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    Two-degree trees
    Pu QIAO, Xingzhi ZHAN
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 1-4.   DOI: 10.3969/j.issn.1000-5641.2023.02.001
    Abstract207)   HTML20)    PDF (427KB)(129)      

    A graph is called a two-degree graph if its vertices have only two distinct degrees. A two-degree tree of order at least three have two degrees, $ 1 $ and $ d $ for some $ d\geqslant 2; $ such a tree is called a $ (1,d) $ -tree. Given a positive integer $ n, $ we determine: (1) the possible values of $ d $ such that there exists a $ (1,d) $ -tree of order $ n; $ (2) the values of $ d $ such that there exists a unique $ (1,d) $ -tree of order $ n $ , and (3) the maximum diameter of two-degree trees of order $ n. $ The results provide a new example showing that the behavior of graphs may sometimes be determined by number theoretic properties.

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    A landscape simulation modeling method based on remote sensing images
    Zehua WANG, Yan GAO, Mingang CHEN
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 82-94.   DOI: 10.3969/j.issn.1000-5641.2023.02.010
    Abstract307)   HTML13)    PDF (4124KB)(110)      

    Traditional virtual terrain modeling commonly uses a procedural generation method based on manual design, which cannot be used for competent simulation modeling tasks that need to restore real environments, such as in military applications. In this paper, we proposed a landscape simulation modeling method based on remote sensing images. The core of our proposed method is a landscape blended texture generation network (LBTG-Net); this method uses a blended texture generator (BTG) to generate landscape blended textures with the supervision of a style discriminator (SD) and multi-stage classification loss. Then, we procedurally build the complete virtual environment based on the blended texture generated by LBTG-Net. Our method has two main features: (1) accurate land-cover classification ability of remote sensing image inputs; and (2) high quality landscape blended texture outputs to guarantee virtual landscape modeling quality. We used multispectral image data from the Sentinel-2 satellite as the experimental dataset. The experimental results showed that our method offered high performance under mainstream land-cover classification evaluating indicators and can accurately reproduce the environmental distribution of input remote sensing images while completing high-quality virtual terrain simulation modeling.

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    Responses of saltwater intrusion in the Changjiang Estuary to various river discharge under a persistent and strong northerly wind
    Wei QIU, Jianrong ZHU
    Journal of East China Normal University(Natural Science)    2023, 2023 (3): 132-146.   DOI: 10.3969/j.issn.1000-5641.2023.03.013
    Abstract111)   HTML17)    PDF (6717KB)(109)      

    In February 2014, a persistent and strong northerly wind caused an extremely severe saltwater intrusion event in the Changjiang Estuary, which posed a threat to the safety of water intake from this source. Increasing river discharge from upstream reservoirs in the river basin is a method to combat severe saltwater intrusion. To simulate and analyze the effects of various river discharges on saltwater intrusion, we used the Unstructured quadrilateral grid, Finite-differencing, Estuarine and Coastal three-dimensional Ocean numerical Model (UnFECOM). By taking into account realistic river discharge and wind conditions, the model accurately reproduced the extremely severe saltwater intrusion process that occurred in February 2014. Our findings indicated that the net water flux (NWF) across the section at the upper reaches of the North Channel (NC) remained landward during the most critical period of saltwater intrusion from February 10 to 13, 2014, despite the increase in river discharge. However, the magnitude of NWF tended to decrease with increasing river discharge. The net water diversion ratio (WDR), NWF (Net Water Flux), and salt flux increased with the increase in river discharge. Under realistic river discharge conditions, WDR was –29% (the negative sign indicates that the NWF is landward), NWF was –2300 m 3/s, and the net salt flux (NSF) was –68 t/s, indicating that the NWF and NSF were landward due to the landward Ekman transport effect induced by the persistent severe northly wind. When the river discharge increased by 3000 m 3/s, WDR and NWF across the section were nearly zero, and NSF was –34 t/s. When the river discharge increased by 8000 m 3/s, WDR was 21.5% and NWF was seaward, at 3550 m3/s. NSF was –6 t/s and landward. At the water intake of Qingcaosha Reservoir, the longest continuous unsuitable water intake time decreased slightly when the river discharge increased by less than 4000 m 3/s. When the river discharge increased to 5000 m3/s, the longest continuous unsuitable water intake time decreased significantly to 10.5 days. It may be challenging to achieve the necessary value and duration of river discharge increase required for the actual operation of the Three Gorges Reservoir. To ensure the safety of water intake, implementing an early warning and forecasting system for saltwater intrusion and storing water into the reservoir at a high level before the intrusion occurs are recommended as effective methods.

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    Diversity of plants in Chinese Taoist temples and the distribution pattern of Taoist tree species
    Wei CHANG, Yongchuan YANG, Cheng JIN, Xinyang WANG, Li HUANG, Lihua ZHOU, Siwei HU
    Journal of East China Normal University(Natural Science)    2023, 2023 (3): 9-19.   DOI: 10.3969/j.issn.1000-5641.2023.03.002
    Abstract249)   HTML243)    PDF (1768KB)(103)      

    In this study, we obtained tree species from 72 Taoist temples across China. We subsequently documented the tree species composition, distribution pattern, and impact factors in different regions to determine the role of Taoist temples in biodiversity protection. The results showed that: ① Among 72 Taoist temples sampled across China, we observed a total of 354 species of trees, belonging to 85 families and 208 genera; ② The tree species in the Taoist temples were mainly native species, and the mean value for the proportion of native species in each Taoist temple was 62.5%±19.8% (mean ± standard deviation). Most of the Taoist temples (77.8%), moreover, housed threatened tree species; ③ Taoist tree species originated largely from subtropical regions, with the Yangtze River Basin being the most represented, especially in the southwest and south-central regions where a relatively large proportion of ethnic minorities reside; ④ The main factors affecting the distribution of Taoist tree species were geography and climate, but their composition was indistinguishable within each climate zone. As the climatic zone moves northward, there is no religious tree species replacement phenomenon (i.e., replacing the original religious tree species by native tree species with similar morphology or cultural meaning). The above results indicate that Taoist temples are rich in plant resources, which are potential biodiversity treasures. Thus, they play an essential role in protecting and maintaining biodiversity, with the potential to serve as a reference for regional ecological restoration and urban green space construction.

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    A class of second-order semilinear singularly perturbed boundary value problems with turning points
    Min ZHAO, Mingkang NI
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 26-33.   DOI: 10.3969/j.issn.1000-5641.2023.02.005
    Abstract142)   HTML11)    PDF (1686KB)(97)      

    The dynamical behavior of a class of second-order semilinear singularly perturbed Neumann boundary value problems with a turning point are studied. Firstly, we establish sufficient conditions for the exchange of stabilities near the turning point. By correcting the regularized equation of the degenerate problem, the accuracy of the asymptotic solution to the original problem is improved. Secondly, the Nagumo theorem is used to prove the existence of a smooth solution. Finally, a specific example is used to verify the validity of the results.

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    Target-dependent event detection from news
    Tiantian ZHANG, Man LAN
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 60-72.   DOI: 10.3969/j.issn.1000-5641.2023.02.008
    Abstract188)   HTML14)    PDF (1822KB)(94)      

    In real-world scenarios, various events in the news are not only too nuanced and complex to distinguish, but also involve multiple entities. To address these problems, previous event-centric methods are designed to detect events first and then extract arguments, relying on imperfect performance for event trigger detection; this process, however, is unfit to deal with the sheer volume of news in the real world. Given that the performance of named entity recognition (NER) is satisfactory, we shift our perspective from an event-centric to a target-centric view. This paper proposes a new task: target-dependent event detection (TDED), which aims to extract target entities and detect their corresponding events. We also propose a semantic and syntactic aware approach to support thousands of target entity extractions first and subsequently the detection of dozens of event types; this approach can be applied to data from massive corporations. Experimental results on a real-world Chinese financial dataset demonstrated that our model outperformed previous methods, particularly in complex scenarios.

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    Contrast structure in a singularly perturbed delay reaction-diffusion equation
    Qingzhao GAN, Mingkang NI
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 34-47.   DOI: 10.3969/j.issn.1000-5641.2023.02.006
    Abstract142)   HTML13)    PDF (790KB)(93)      

    This paper considers a Neumann boundary value problem of a singularly perturbed delay reaction-diffusion equation with a nonlinear reactive term. By using the boundary layer function method, contrast structure theory, and contraction mapping principle, the asymptotic expansion of the solution is constructed, and the existence of a uniformly valid solution is proven. Finally, an example is presented to show the effectiveness of our result.

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    Strongly Gorenstein weak flat modules
    Yanhui SONG, Ting GUO
    Journal of East China Normal University(Natural Science)    2023, 2023 (2): 12-16.   DOI: 10.3969/j.issn.1000-5641.2023.02.003
    Abstract157)   HTML10)    PDF (499KB)(93)      

    In this paper, we introduce the notion of strongly Gorenstein weak flat modules, and we subsequently provide homological characterizations of strongly Gorenstein weak flat modules. It is shown that a Gorenstein weak flat module is a summand of a strongly Gorenstein weak flat module.

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    A survey on the cell theory of weighted Coxeter groups
    Jianyi SHI, Qian HUANG
    Journal of East China Normal University(Natural Science)    2023, 2023 (6): 1-13.   DOI: 10.3969/j.issn.1000-5641.2023.06.001
    Abstract105)   HTML19)    PDF (1429KB)(90)      

    We give a survey on the contribution of our research group to the cell theory of weighted Coxeter groups. We present some detailed account for the description of cells of the affine Weyl group $ \widetilde{C}_n $ in the quasi-split case and a brief account for that of the affine Weyl group $ \widetilde{B}_n $ in the quasi-split case and of the weighted universal Coxeter group in general case.

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    Journal of East China Normal University(Natural Science)    2023, 2023 (6): 0-.  
    Abstract66)      PDF (487KB)(90)      
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    Impact of coastal ecological restoration project on bird diversity and community dynamics
    Kun HE, Ziyu ZHANG, Annan SONG, Qifan SHEN, Jiayi WANG, Xuechu CHEN
    Journal of East China Normal University(Natural Science)    2023, 2023 (3): 158-166.   DOI: 10.3969/j.issn.1000-5641.2023.03.015
    Abstract139)   HTML22)    PDF (831KB)(89)      

    Yingwuzhou Wetland is an artificially restored coastal salt marsh wetland aimed at improving ecosystem services. Development of the wetland has restored the original damaged coastal ecosystem through comprehensive coastline ecological engineering measures. The birds in the study site have been investigated and researched using the route survey method since 2018, and changes in the bird population and species diversity have been analyzed to evaluate the effectiveness of coastal zone ecological restoration projects and the impact of different wetland habitat types on bird diversity. The results showed that 67 bird species were recorded in the wetland, belonging to 13 orders and 32 families, with the largest number of birds belonging to Passeriformes, including 42 species belonging to 18 families. There were 35 species of resident birds, 24 species of winter migratory birds, 10 species of summer migratory birds, and 8 species of migratory birds. Among these, one species of national class I and seven species of class II are in the List of Key Protected Wild Animals in China, respectively. Remiz consobrinus, Gallinula chloropus, Acridotheres cristatellus, Tachybaptus ruficollis, Spodiopsar cineraceus, Hirundo rustica, and Passer montanus were the dominant species. The number of wetland bird species increased annually. There were significant differences in the bird species, quantity, and Shannon–Wiener indexes among different seasons. The declining trends of bird species, quantity, and Shannon–Wiener index were in the orders of fall > winter > spring > summer, fall > winter > summer > spring, and fall > spring > winter > summer, respectively. The bird numbers and species were the highest in the natural wetland complex area. Declining trends of the Shannon–Wiener index in different habitat areas were observed for the natural wetland complex area, salt marsh wetland restoration area, clear water conservation area, lawn activity area, and wetland purification exhibition area. The ecological restoration of the coastline has enriched the bird diversity of the wetland. Habitats with rich patch types and high patch mosaic have a markedly positive impact on bird diversity. The results of this study can provide a scientific basis for the coastal ecological restoration and sustainable development of coastline wetlands.

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