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25 November 2025, Volume 2025 Issue 6 Previous Issue   

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The ergodicity of population dynamics driven by truncated α-stable processes Zhenzhong ZHANG, Xiaofan GU, Junbo TONG, Xin ZHAO, Xinping LI 2025, 2025 (6):  1-13.  doi: 10.3969/j.issn.1000-5641.2025.06.001 Abstract ( 2 )   HTML ( 1 )   PDF (689KB) ( 0 )   Save In order to study the dynamic behavior of biological populations in complex environments, we consider an n-dimensional population model driven by a truncated α-stable process. First of all, a generalized Khasminskii theorem for pure jump systems has been established. Then, the regular points such a system are discussed. Finally, we give a sufficient criterion to verify ergodicity for such a pure jump population dynamic system. References | Related Articles | Metrics

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Finiteness and boundedness of metrics on state spaces Botao LONG, Wentao SHEN, Yueliang LIANG 2025, 2025 (6):  14-18.  doi: 10.3969/j.issn.1000-5641.2025.06.002 Abstract ( 3 )   HTML ( 0 )   PDF (458KB) ( 0 )   Save We provide a sufficient condition under which the finiteness and boundedness of metrics, as defined by Rieffel within the framework of Banach spaces, are equivalent. Additionally, we characterize the boundedness of metrics on the state spaces of $C^*{\text{-}} $algebras from multiple perspectives. References | Related Articles | Metrics

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Electricity theft detection based on transfer learning and attention hybrid neural network Lishen CHEN, Peng PU, Jianghai QIAN 2025, 2025 (6):  19-28.  doi: 10.3969/j.issn.1000-5641.2025.06.003 Abstract ( 4 )   HTML ( 0 )   PDF (743KB) ( 0 )   Save In this study, several issues with current electricity theft detection methods are addressed, notably the reliance on one-dimensional electricity load time series data to develop a singular model. These approaches are often plagued by low detection accuracy, and they require extensive training parameters and a significant number of training samples when computer vision models are directly applied to two-dimensional images of electricity load time series. To overcome these challenges, a novel electricity theft detection method that utilizes a hybrid neural network, combining transfer learning and attention mechanisms, is proposed. The training demands of the ConvNeXt model are reduced via the integration of transfer learning, significantly enhancing its performance. Additionally, a bi-directional long short-term memory (BiLSTM) model is integrated to support the training of the refined ConvNeXt model by extracting global nonlinear features from one-dimensional load time-series data. Furthermore, SimAM and multi-headed self-attention (MHSA) mechanisms are incorporated to improve the feature representation capability of the hybrid model. The experimental verification of the proposed method in the China State Grid public dataset shows that $A_{\mathrm{UC}} $, $M_{{\text{AP@}}100} $, $ M_{{\text{AP@}}200}$, and $F_1 $ metrics of the proposed model can be effectively enhanced when compared to those of other deep learning classification models. For example, $F_1 $ is improved by 9.1% compared to that obtained via t-LeNet algorithm. Figures and Tables | References | Related Articles | Metrics

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Dual decision adaptive freezing for fast and accurate transfer learning Zefeng HE, Fuke SHEN, Tongquan WEI 2025, 2025 (6):  29-38.  doi: 10.3969/j.issn.1000-5641.2025.06.004 Abstract ( 1 )   HTML ( 0 )   PDF (1669KB) ( 0 )   Save With the rapid development of deep learning, model size and accuracy have been increasing. However, in the quest for greater accuracy, large training datasets are often necessary for training, which often slows down training and exacerbates carbon emissions. To address these challenges, researchers have proposed a number of approaches, including transfer learning. However, existing transfer learning methods either fine-tune the entire network or only a part of it, such as the final classifier layer. The former often leads to slow migration training, and the latter reduces the accuracy of migration training. To solve these problems, a dual-decision adaptive freezing (DDAF) method is proposed for the transfer learning process. First, a group decision module is used to decide on the layers of the neural network that may require freezing. Subsequently, a layer decision module is used to reach a decision on these layers and determine the layers to eventually freeze, thereby finally freezing the layers that need to be frozen, to minimize the possibility of erroneous freezing, improve the accuracy of training, and accelerate the speed of transfer learning training. Extensive experiments showed that the proposed method improved training speed by 1.97 times with minimal loss of accuracy compared to the traditional method of fine-tuning the entire network and significantly improved the accuracy by 34.52% with minimal loss of training speed compared to fine-tuning only the last layer. Figures and Tables | References | Related Articles | Metrics

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Optimized design and implementation of stepper motor start-stop control algorithm in the sputum smear slide preparation system Quanjie ZHUANG, Zijiao CHEN, Zhirui XIAO, Hongying LIU 2025, 2025 (6):  39-45.  doi: 10.3969/j.issn.1000-5641.2025.06.005 Abstract ( 2 )   HTML ( 0 )   PDF (901KB) ( 0 )   Save Stepper motors play a key role in the workflow of automatic sputum smear slide preparation and staining. During the startup and shutdown processes of a motor, the rapid changes experienced by the motor speed necessitate excellent motor startup and shutdown control algorithms. First, the overload phenomenon caused by the excessive torque required during the sudden high-speed startup of the motor should be avoided to protect the motor from damage. Second, during deceleration, sudden stoppage of the high-speed rotating motor should be prevented to reduce the inertial impact on the motor and minimize the resulting motion deviation. This study aimed to optimize the startup and shutdown control algorithms for stepper motors. During the startup and shutdown stages, an S-shaped curve was adopted to achieve smooth changes in motor speed. This S-shaped speed change curve was designed based on the Logistic function, to ensure smooth changes in motor speed during startup and shutdown, thereby avoiding the impact caused by sudden acceleration or deceleration. A 7-segment acceleration and deceleration optimization algorithm was employed to achieve effective control of the motor overall motion. Simulation experiments were conducted to verify the effectiveness of the algorithm. The stepper motor exhibited an S-shaped change in its speed-time curve during the startup and shutdown intervals, ensuring smooth startup and shutdown of the motor. Actual test results show that after adopting the S-shaped acceleration and deceleration startup and shutdown control algorithm, the positional error was within ±0.05 mm, a significant reduction compared to the ±0.9 mm caused by the trapezoidal control algorithm. This demonstrates that the S-shaped acceleration and deceleration startup and shutdown control algorithms achieve remarkable results in reducing positional errors. Figures and Tables | References | Related Articles | Metrics

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Research on video question answer for the development of theory of mind Yuanyuan MAO, Xin LIN, Qin NI, Ciping DENG, Yiming MA 2025, 2025 (6):  46-52.  doi: 10.3969/j.issn.1000-5641.2025.06.006 Abstract ( 2 )   HTML ( 0 )   PDF (664KB) ( 0 )   Save In recent years, with the continuous development of machine theory of mind (ToM), research has found that the development of machine ToM differs significantly from the triangular model of children’s ToM development. Consequently, we propose a machine-oriented theory of mind triangular model. This model elucidates the relationships among various tools in the process of developing machine ToM. Additionally, we introduce an evaluation dataset suitable for the dynamic assessment of machine ToM. Finally, this paper designs a VideoQA(video question answer) model, named FOMemNet (fact and observer memory network), specifically tailored for cognitive reasoning—a model addressing belief, desire, and intention reasoning. Considering that models in cognitive reasoning tasks need to infer from the observer’s perspective, we incorporate the FOEM (vision fact and observer perception encoder module) module in FOMemNet for the fusion of multimodal features, thereby obtaining visual factual features and observer features. Subsequently, the model utilizes the FOF (fact and observer fusion) module and two memory modules to integrate features from both perspectives for obtaining a global representation. FOMemNet results in a 2.27% improvement of BDIQA. Our experiments demonstrate the effectiveness of the concept of fact and observer perception in enhancing cognitive reasoning abilities in VideoQA. Figures and Tables | References | Related Articles | Metrics

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Cold-start problem of federated recommendation systems based on conditional variational autoencoder Xinyue LYU, Xinli HUANG 2025, 2025 (6):  53-62.  doi: 10.3969/j.issn.1000-5641.2025.06.007 Abstract ( 1 )   HTML ( 0 )   PDF (1036KB) ( 0 )   Save The cold-start problem of recommendation systems which affects recommendation quality, service experience, privacy, and security, has become one of the most challenging research hotspots in the field. Thus, our study proposed an integrated federated learning framework for conditional variational autoencoders (CVAE), termed as FedCVAE. Individual CVAE models were trained on each client’s local data to generate embeddings of users, items, and user interaction sequences. These embeddings were used as inputs for the essential recommendation model. The model’s global parameters were aggregated and updated at the server-side, which was subsequently disseminated back to the client-side to support local CVAE models in updating hyperparameters. While the model improves its accuracy in handling sparse data, it also enhances its ability to preserve privacy, thus effectively mitigating the cold-start problem. The experimental results indicate that in three typical cold-start scenarios, the model presented in this paper outperformed mainstream recommendation algorithms. The mean absolute error metric reduces by approximately 0.8% ~ 5.5%, and the Hit@5 metric improves by approximately 1.2% ~ 5.7%. The model demonstrated superior performance, delivering high-quality recommendation services that balance personalized experiences and enhanced privacy protection. Figures and Tables | References | Related Articles | Metrics

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Coupled models of soil amendments and vegetation restoration for waste dump reclamation of open-pit coal mines Min QUAN, Xiangqian ZHU, Liangjun DA 2025, 2025 (6):  63-70.  doi: 10.3969/j.issn.1000-5641.2025.06.008 Abstract ( 3 )   HTML ( 0 )   PDF (840KB) ( 0 )   Save Soil fertility is low and vegetation recovery is sluggish at the waste dumps in open-pit coal mines in Northwest China. Although soil amendment strategies for waste dumps are well-developed, vegetation restoration methods after soil amendment have been little explored. To address this, we conducted field experiments at a waste dump in the Heidaigou open-pit coal mine in Inner Mongolia. The experiments included three artificial vegetation reclamation approaches (establishing pastures, crops, or forests) and one natural vegetation recovery, all applied after soil amendment. We assessed the effects of combining soil amendment strategies with various vegetation restoration methods on the physicochemical attributes and belowground biomass at waste dumps. The results demonstrated that integrating soil amendments incorporating water-retaining substances and organic fertilizer into the upper 30 cm of the soil with artificial vegetation reclamation (establishing pastures, crops, or forests) substantially improved the soil nutrient profiles and belowground biomass within one year. This strategy was more effective than relying solely on natural vegetation recovery after soil amendment. However, none of the combinations of soil amendment and artificial vegetation reclamation quickly improved the soil pH level or electrical conductivity. Additionally, we observed positive correlations among soil organic matter, available phosphorus, and belowground biomass. The optimal strategy for rapidly augmenting soil fertility at waste dump sites is pairing soil amendments with forest reclamation. These insights provide valuable scientific guidance for the restoration of the waste dumps of open-pit coal mines throughout Northwest China. Figures and Tables | References | Related Articles | Metrics

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Exploration of a multi-trophic serial recirculating aquaculture based on system ecology Tenzindolkar, Qiang WANG 2025, 2025 (6):  71-81.  doi: 10.3969/j.issn.1000-5641.2025.06.009 Abstract ( 2 )   HTML ( 0 )   PDF (1178KB) ( 0 )   Save Since the 1970s, the pursuit of high efficiency and output has driven aquaculture toward intensive and large-scale production, exemplified by flow-through and static high-density systems. While these models achieve high yields, their excessive biological loads and resource inputs result in severe resource waste and water pollution, hindering sustainable development. To overcome these limitations, In this study, we constructed a small-scale multi-trophic serial recirculating aquaculture (MSRA) system with four nutrient utilization tiers of Micropterus salmoides, Chlorella sp., Hyriopsis cumingii, and Vallisneria natans in series. Compared the operation, biological growth, water purification effect, and nitrogen utilization rate between the MSRA system and monoculture aquaculture (MA) system, the MSRA system demonstrated superior performance: Fish survival was improved in the MSRA system, based on biomass growth and feed utilization efficiency, which were 1.68 and 1.65 times higher, respectively, in the MSRA system than the MA system. The MSRA system effectively purified the aquaculture wastewater and significantly reduced the chemical oxygen demand and the total ammonia nitrogen and nitrite (${\mathrm{NO}}_2^- $-N) concentrations (p < 0.05). The nitrogen-use efficiency of the MSRA system was 27% higher than that of the MA system, and 11% higher than that of a traditional aquaponics system. These results showed that this aquaculture model realized zero discharge of aquaculture wastewater and improved the level of nutrient recycling within the system. Figures and Tables | References | Related Articles | Metrics

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Tree temperature shift and regulation of various landscape tree species under high-temperature stress: A case study in Shanghai Chenshan Botanical Garden Ming LIU, Zhiyuan WANG, Kankan SHANG 2025, 2025 (6):  82-93.  doi: 10.3969/j.issn.1000-5641.2025.06.010 Abstract ( 1 )   HTML ( 0 )   PDF (2389KB) ( 0 )   Save We have investigated the correlations between tree temperature and leaf physiological variables (net photosynthetic rate, respiration rate, and stomatal conductance) and functional traits (leaf area, leaf thickness, specific leaf weight and specific leaf area) by measuring tree temperatures using infrared thermal imager in Shanghai Chenshan Botanical Garden taking 37 tree species as sample. In general, the average temperature difference between the crown and the air is 0.6℃, while the average temperature difference between the trunk and the air is 2.1℃. Under high temperature stress, the temperature regulation mechanisms of different landscape tree species have significant differences. According to the regulation shifts of the tree temperature in response to high-temperature stress, tree species can be divided into 3 types, i.e., rising type, maintenance type, and descending type. Tree species with larger single-leaf areas, specific leaf areas, and thinner leaf thickness have relatively lower crown temperatures and higher physiological levels of leaves, resulting in relatively better cooling effects. This can be used as a reference for selecting suitable tree species for regulating microclimate. Figures and Tables | References | Related Articles | Metrics

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Carbon emissions accounting and carbon emissions reduction benefits of sponge city construction based on life cycle assessment Xingyan BAO, Ruihui CHENG, Sheng XIE, Zhaokang WU, Haiyan KUAI, Boxiao ZHANG, Bowen LYU, Kai YANG 2025, 2025 (6):  94-105.  doi: 10.3969/j.issn.1000-5641.2025.06.011 Abstract ( 2 )   HTML ( 0 )   PDF (1503KB) ( 0 )   Save In response to the new requirements for systematic sponge city development under China’s “carbon peaking and carbon neutrality” strategy, scientifically evaluating the carbon emissions and carbon emission reduction benefits of sponge city construction holds significant theoretical and practical value. This study took Wuhu, a national sponge demonstration city, as an example. Taking on the perspective of the whole life cycle, and combining the emission factor method and the Technical Guidelines for Carbon Emission Accounting for Sponge City Construction in Anhui Province, this study utilized the carbon emission accounting method for sponge cities that is applicable to engineering in practice, and evaluated the carbon emission and emissions reduction results of four types of typical sponge projects in 2022. Based on this, the study took a residential community as a representative example and employed the NSGA-Ⅱ algorithm to explore strategies for achieving synergistic carbon emissions reduction by optimizing the configuration of multiple types of sponge facilities. The results indicate the following. (1) The carbon emissions from sponge city projects in Wuhu are primarily concentrated in the construction phase, with total emissions of 11438.6 t. Among these, material production and transportation account for 53% and 36%, respectively, indicating considerable potential for emissions reduction. (2) During the operational phase, sponge cities largely rely on sustained natural processes to function, with the carbon reduction effects being relatively concentrated in this stage. The total carbon emissions during this phase are approximately –242.3 t. Assuming that existing operational conditions are maintained without any new facilities, sponge facilities are expected to achieve a cumulative carbon reduction of 7269.7 t in 30 years. Although the annual carbon reduction is relatively limited, long-term operation can gradually offset carbon emissions from the construction phase, demonstrating strong carbon neutrality potential. (3) In terms of specific facility types, green stormwater infrastructure such as grassed swales (4.95 kg/m2) and sunken green spaces (11.35 kg/m2) exhibit relatively low carbon emissions intensities during the construction phase. The carbon reduction benefits of sponge facilities in the operation stage are significantly influenced by their functional characteristics and the scale of implementation. (4) Taking a residential community as an example, and based on the annual total runoff control rate requirement, the coordinated carbon reduction capacity of sponge facilities can be enhanced by reasonably adjusting the scales of sunken green spaces, permeable pavements, rain gardens, and grassed swales. This study provides a quantitative evaluation of multi-facility sponge city systems from a holistic perspective, offering methodological support and a theoretical reference for the development of low-carbon urban drainage systems. Figures and Tables | References | Related Articles | Metrics

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Effects of soil conditioners on soil properties and vegetable growth in an open-pit coal mine dump Xiaoliang JIAO, Xinxin YU, Heyi GONG, Kun SONG, Liangjun DA 2025, 2025 (6):  106-115.  doi: 10.3969/j.issn.1000-5641.2025.06.012 Abstract ( 2 )   HTML ( 0 )   PDF (760KB) ( 0 )   Save This study addresses the challenge of water and nutrient deficiencies in the planted soil of spoil dumps in open-pit coal mines by investigating the effectiveness of soil amendments containing a water-retaining agent, organic fertilizer, and microbial inoculant in enhancing soil properties and promoting plant growth. A pot experiment was conducted using Brassica rapa var. chinensis as the model plant to evaluate the effects of different amendment dosages. Key soil parameters were analyzed, including pH, electrical conductivity, alkali-hydrolyzable nitrogen, available phosphorus, available potassium, and organic matter content. Plant growth indicators such as plant height, leaf number, and dry biomass were measured. The findings indicated that applying the water-retaining agent and organic fertilizer significantly improved soil properties and promoted plant growth, whereas the microbial inoculant did not produce statistically significant effects. The optimal combined effect of the amendments on soil properties and plant growth was achieved at a water-retaining agent dosage of 5‰ and an organic fertilizer dosage of 30%. Figures and Tables | References | Related Articles | Metrics

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A study on the control effectiveness of Spartina alterniflora based on combined cutting and herbicide application measures Zongyue LIU, Yunyi CHI, Qiang WANG 2025, 2025 (6):  116-127.  doi: 10.3969/j.issn.1000-5641.2025.06.013 Abstract ( 5 )   HTML ( 0 )   PDF (2219KB) ( 0 )   Save Spartina alterniflora is a globally invasive plant that has caused significant damage to coastal ecosystems, including biodiversity loss, decline of native vegetation, alteration of benthic communities, and degradation of bird habitats. Effective control of S. alterniflora is therefore critical for coastal ecological conservation. Current control methods—physical, chemical, biological, and integrated—have limitations: physical removal alone is often inefficient, and chemical control poses risks of ecological pollution. This study evaluates an integrated approach combining mechanical cutting with low-dose herbicide application to improve control efficacy and assesses its impact on soil microbial diversity. In August 2022, two sites with uniformly growing S. alterniflora were selected, each divided into 21 quadrats of 1 m × 1 m. One site was mowed at the end of August, while the other remained uncut. In September, three concentrations of Haloxyfop-P-methyl (HP) and Glyphosate (GP) were applied. Plant responses were monitored during the flowering stage (September), seed-setting stage (October), the end of the growing season (December), and the following April. Four treatments were compared: HP alone, GP alone, cutting followed by HP, and cutting followed by GP. Soil samples were collected from herbicide-treated and control quadrats for physicochemical analysis. High-throughput sequencing was used to characterize bacterial and fungal community structure and diversity. Data were analyzed using one-way ANOVA with LSD post-hoc tests following validation of homogeneity of variances (Levene’s test). Results showed that: (1) Cutting followed by HP application during the flowering stage effectively controlled S. alterniflora, with a dose of 150 mg/m2 achieving 98.93% control efficiency by the end of the growing season, while doses of 300 mg/m2 and 600 mg/m2 achieved complete plant mortality; all doses significantly inhibited regrowth the following year, with suppression rates of 93.49%, 92.68%, and 96.48%, respectively. (2) Cutting during flowering significantly reduced the sexual reproduction capacity of regenerated plants. (3) Although the combined treatment reduced the relative abundance of Ascomycota in soil fungi, it did not significantly affect overall bacterial or fungal diversity. The combined treatment of cutting followed by Haloxyfop-P-methyl application at 150 mg/m2 effectively controls S. alterniflora and strongly suppresses its regrowth without causing significant adverse effects on soil microbial diversity, supporting the development of efficient and environmentally sustainable management strategies for this invasive species. Figures and Tables | References | Related Articles | Metrics

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Portable high-frequency radar antenna pattern calibration and multiple data quality control methods Xuyun WU, Pixue LI, Yuqi WANG 2025, 2025 (6):  128-140.  doi: 10.3969/j.issn.1000-5641.2025.06.014 Abstract ( 2 )   HTML ( 0 )   PDF (8798KB) ( 0 )   Save Given their wide coverage, high resolution, and all-weather observational capabilities, high-frequency radars hold considerable potential for ocean current observation and forecasting. In this study, we address two key steps in the radar data processing chain, namely, antenna pattern calibration using an unmanned aerial vehicle (UAV) and anomaly detection using multiple algorithms. A UAV equipped with a beacon–global positioning system was employed for radar antenna pattern calibration. Experiments were conducted at the Jinshan–Luchaogang radar station in Shanghai, China. Following calibration, the root-mean-square errors of current direction and speed decreased by 17.76° and 0.04 m/s, respectively, with corresponding improvements in the correlation coefficients of 0.11 and 0.23. Furthermore, quality control of the radar-derived current data from the Jinshan–Luchaogang area was implemented using three methods: the standard deviation threshold method, boxplot analysis, and Isolation Forest algorithm. All three methods effectively identified anomalies in the marginal and nearshore regions of the observed current fields. Among them, the Isolation Forest algorithm exhibited superior spatiotemporal sensitivity and a broader detection range. These results indicate that combining improvements in the high-frequency radar data quality control with UAV-based antenna calibration can substantially enhance data quality and improve the reliability of high-frequency radar-derived data for ocean dynamic monitoring. Based on these findings, future research is recommended to incorporate multi-source observations and physical constraints to further improve high-frequency radar data quality control and calibration. Figures and Tables | References | Related Articles | Metrics

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Effects of typhoons landfalling on the north bank of Hangzhou Bay, Shanghai, on saltwater intrusion in the Changjiang River Estuary: A case study of typhoons “Bebinca” and “Pulasan” in September 2024 Cheng QIU 2025, 2025 (6):  141-151.  doi: 10.3969/j.issn.1000-5641.2025.06.015 Abstract ( 2 )   HTML ( 0 )   PDF (4155KB) ( 0 )   Save Saltwater intrusion in the Changjiang River Estuary is generally considered a key threat to urban water supply security, and the risks may be exacerbated under the weather conditions of concurrent typhoons and low river discharge. Taking the successive landfalls of typhoons “Bebinca” and “Pulasan” along the north bank of Hangzhou Bay, Shanghai, in September 2024, as examples, we employed a high-resolution 3D estuarine saltwater intrusion numerical model to simulate the differential impacts of the typhoons on saltwater intrusion in the Changjiang River Estuary. The results indicated that whereas the onshore wind-driven circulation promoted a significant enhancement of the frontal intrusion upstream of saltwater in the North Channel during the landfall of typhoon “Bebinca,” the circulation weakened the saltwater intrusion in the South Passage. In contrast, given its less intense strength and deflected track, typhoon “Pulasan” had a comparatively limited impact on the frontal intrusion in the North Channel. Given their limited duration, the short-term storm surges induced by the typhoons, which coincided with spring tides, caused comparatively little saltwater spillover from the North Branch into the South Branch. The findings of this study reveal the response mechanisms of saltwater intrusion to the landfall of typhoons on the north bank of Hangzhou Bay. This will provide a scientific basis for defense against compound natural disasters involving the combined effects of typhoons and saltwater intrusion on urban water supplies under extreme climate conditions. Figures and Tables | References | Related Articles | Metrics