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Aiming at the lack of effective analysis and identification of operational area in the traditional battlefield situation awareness process, a method of aerial battlefield target trajectory analysis method for operational area extraction is proposed. Firstly, based on the improved Douglas-Peucker algorithm, the featured trajectory is extracted based on the original target trajectory, thus reducing the trajectory redundant information. Secondly, the clustering by fast search and find of density peaks (CFSFDP) algorithm is used to cluster the featured trajectory, which obtains multiple featured points clusters. Finally, each featured points cluster is scanned based on Graham's convex hull algorithm to obtain closed polygons to characterize the combat areas. The feasibility and effectiveness of the algorithm model are verified by several case simulations.

Aiming at the lack of effective analysis and identification of operational area in the traditional battlefield situation awareness process, a method of aerial battlefield target trajectory analysis method for operational area extraction is proposed. Firstly, based on the improved Douglas-Peucker algorithm, the featured trajectory is extracted based on the original target trajectory, thus reducing the trajectory redundant information. Secondly, the clustering by fast search and find of density peaks (CFSFDP) algorithm is used to cluster the featured trajectory, which obtains multiple featured points clusters. Finally, each featured points cluster is scanned based on Graham's convex hull algorithm to obtain closed polygons to characterize the combat areas. The feasibility and effectiveness of the algorithm model are verified by several case simulations. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective To investigate various trajectories of physical activity (PA) in a population from the southwestern China and to analyze their associations with the occurrence of carotid plaque as cardiovascular diseases being a leading cause of disability and premature death worldwide. Methods This study utilized data from three surveys conducted in 2018, 2020, and 2023, involving the China Multi - Ethnic Cohort (CMEC) healthy lifestyle promotion sub - cohort participants living in Jianyang and Pidu Districts of Sichuan Province of China. The primary outcome of interest was the occurrence of carotid plaque, measured in 2023. To classify the types of PA trajectories based on metabolic equivalents (METs), a latent class trajectory model was employed. The associations between different PA trajectories and carotid plaque were examined using logistic-regression analysis. Results A total of 373 participants were included in this study, and the types of PA trajectories were classified into four groups: low MET - stable, moderate MET - stable, high MET - declining, and high MET - ascending groups. Compared to the low MET 一 stable group, both moderate MET 一 stable and high MET 一 declining groups showed a protective effect against the occurrence of carotid plaque. Among them, the moderate MET 一 stable group exhibited the strongest protective effect (OR =0.16, 95% CI: 0. 07 - 0. 34), followed by the high MET 一 declining group (OR =0.34, 95%CI: 0. 20 一 0.59). Subgroup analysis revealed that the high MET 一 ascending group demonstrated a stronger protective effect in males (OR =0. 16, 95%CI: 0. 03 一 0. 70) and individuals with an annual household income of $60,000 Chinese yuan, (OR 二0. 09, 95% CI: 0. 01 - 0. 53), with significant interaction effects (P <0. 05). Conclusion Maintaining steady moderate - intensity PA may reduce the risk for carotid plaque, and protective effects are more pronounced in the high MET - ascending group in males and those with a higher annual household income. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

At present， parallelogram traction steering mechanism is mostly adopted in traction vehicles used in warehousing cargo loading and transfer. Because the steering mechanism does not conform to Ackermann's principle， the sliding friction force is large when steering， which will lead to traction and steering operation laborious. A trapezoidal traction steering mechanism based on Ackerman principle is designed， and uses the sequential quadratic programming genetic algorithm in multivariate nonlinear programming to optimize the specific dimensions of the trapezoidal traction steering mechanism， the size parameters which more satisfy the Ackerman principle are obtained. A prototype is made based on the optimized parameters. By using the Adams dynamics simulation software， the simulation and comparative experiment of the trapezoidal steering mechanism with the optimized parallelogram mechanism from three dimensions of steering trajectory， steering start torque， and energy conversion efficiency are carried out. The analysis results show that the optimized mechanism has a smoother steering trajectory， smaller steering starting torque and higher energy conversion efficiency.

Objectives: In recent years, trajectory data generated by various location‑aware devices have been widely used in a host of fields such as urban planning, intelligent transportation, public health, and behavior analysis, and have produced huge social and economic value. However, the conventional vector representation model and the analysis algorithms based on it have high computational complexity and cannot meet the high time‑efficient application requirements of large‑scale trajectory data. To address the above problems, we propose a trajectory data management and analysis framework based on a geographical grid model, which provides a new technical framework for the entire chain of “representation‑management‑analysis‑application” of trajectory data mining. Methods: This framework includes five parts: (1) Construction of geographical grid model. The Earth's surface space is subdivided level by level according to some rules(e. g., quadtree, octree), and the spatiotemporal position is represented by grid coding.(2) Multi‑ scale coding representation and organization of trajectories. The trajectory data are mapped onto different spatial resolution grid levels according to the spatial position information and precision requirements to implement the spatial one‑dimensional multi‑scale coding representation instead of multi‑dimensional vector coordinates, to reduce the difficulty of organization and management on massive trajectory data. (3) Calculation and analysis of trajectories. The concept of geographical grid calculation is proposed, and the existing complex algorithms are modified by using low complexity coding operations (including intrinsic index, multi‑scale, set operations, etc.) to accelerate the process of trajectory data mining analysis. (4) High‑performance computing technologies. We further utilize the discreteness of geographical grid model, and com‑ bine the current parallel and distributed high‑performance computing frameworks to achieve distributed storage and concurrent computing on trajectory big data. (5) Applications of trajectory mining. Based on this frame work, a series of high time‑efficient applications are proposed to better serve the fields of urban management, intelligent transportation, and public safety. In addition, we found several advantages of combining geographical grid model and trajectory data, including large‑scale data storage and management efficiency and flexibility, suitability for high‑performance computing technology, and meeting the needs of automatic control and intelligent computing. Results: Supported by the above theoretical methods, the reliability and effectiveness of the technical framework theory and technical methods have been verified by two applications‑multi‑level real‑time visualizing of urban traffic flow and similarity analysis based on geographical grid model. The results show that the spatiotemporal query and similarity measure under this framework are one to two order of magnitude higher than classic algorithms under the vector coordinates. It has achieved to response within seconds and real‑time visualization while processing billions of trajectory data, which proves the reliability and validity of the theories and technical methods. We explain the content of the proposed trajectory data management and analysis framework from the perspectives of framework design, theoretical analysis, advantages summary, and comparative experiments. Conclusions: It has been verified that the framework has the potential for high‑performance management and analysis of massive trajectory data. In the future, issues such as the tradeoffs between data volume and accuracy, complex network analysis, and multi‑source element association analysis need to be further explored and studied, to build a complete trajectory data management and mining technology system in a geographical grid space. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Heilongjiang University of Science & Technology is the property of Journal of Heilongjiang University of Science & Technology Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The carbon- free car is a kind of car with direction control function,the gravitational potential energy drive. In order to solve the manufacturing error,assembly error affect carbon- free car trajectory problem of inaccurate,through the car trajectory mathematical analysis,the trajectory equation is established. By using Mathematica software,the car trajectory simulation experiments is carried out. Then the sources of error and error forms affect the trajectory changes are analyzed and summarized. Based on this trajectory analysis and the design method of introducing the micrometer and worm gear mechanism into the fine- tune mechanism is proposed,a fine- tuning mechanism and fine- tuning method with higher adjust precision than ever are obtained. Through physical prototype testing,good results is achieved by fine- tuning program in the trajectory modification,a new way of thinking for carbon- free car fine- tuning mechanism design is provided.

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Entomology is the property of Chinese Journal of Applied Entomology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To obtain valuable information from mass mobile user trajectory data,Spark cluster was used to process the user behavior original data of trajectory, the data storaged in the HBase distribution was storaged in the Hive after screening and analysis, the Spark reads the data in the database file card to do the correlation test and K-Means clustering analysis, getting user mode in the distance and the statistical result of the universal law of the travel mode choice. This process provides a feasible solution for user behavior analysis and prediction, which has high research value and practical value. [ABSTRACT FROM AUTHOR]

A passive air sampler was used to monitor the concentration and contamination profile of 18 polychlorinated biphenyls (PCBs) in the atmosphere over the urban and industrial area of Gaolan, a city in northwest China, during the non-heating and heating seasons of 2018, and the sources, pollutant transport, and the health risks of PCB exposure were analyzed and assessed using principle component analysis, trajectory modeling, and inhalation exposure modeling. The atmospheric concentration in the study area ranged from 110.2 to 429.9 pg·m -3 , and the highest average concentration was found at the industrial estate. Tetra-PCBs and penta-PCBs were the dominant homologue groups, and the percentage of tetra-PCBs increased in the heating season. Combustion and industrial thermal processes, PCB-containing electrical equipment, and the combined source of volatilization from paint, combustion, and industrial thermal processes were considered to be the main sources, and the source of combustion and industrial thermal processes contributed the largest proportion of PCBs at 40.8%. Largely, the emission of UP-PCBs would significantly influence PCB pollution in the study area. Trajectory analysis results illustrated that PCBs emitted from sources in the study area would be transmitted to Lanzhou City atmospherically; local pollution would be the main source of PCBs contamination in the study area during the non-heating season, while the atmospheric input of PCBs transmitted from the northwest region would be another source during the heating season. Health risk analysis showed that the non-cancer risk of PCBs exposure was low in all age groups; however, lifetime cancer risks exceeded 10 -6 . PCBs emitted from combustion and industrial thermal processes sources would have a strong impact on resident exposure to PCBs, and adverse health effects would be caused due to long-term inhalation exposure of the inhabitants to PCBs contamination in the study area.