Search

Objective The performances of PTZ laser gas leakage detection system in natural gas stations are analyzed and evaluated. Methods Fully considering the influence factors such as light intensity attenuation, various field environments, and human interference, a set of operable test methods was designed and actual tests were carried out. Results The detection data under different scenes, different distances and different interference factors were obtained. Conclusions Using the test method proposed in this paper to carry out the field test data shows that the PTZ laser gas leakage detection system has high detection accuracy and strong anti-interference ability. It is generally applicable to all kinds of field environments, and has a good application prospect in the field of gas leakage detection in natural gas stations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. 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.)

Since the coronavirus disease 2019 (COVID ‐19) epidemic was kept under control in China, to conduct scientific research on the patterns of the virus transmission has become essential in terms of disease control. Therefore, the demand for the precise and structured trajectory of the individual cases is increasing. While considering the highly unstructured characteristics of the spatiotemporal trajectory source string re‐ trieved from the official website, it is difficult to obtain a precise trajectory efficiently by either hand‐crafted method or an automated algorithm. To address the above contradiction of efficiency and precision in trajec‐ tory extraction, a human ‐computer interactive (HCI) trajectory extraction and validation approach was pro‐ posed based on natural language processing (NLP) artificial intelligence algorithm, the source string was firstly analyzed by NLP, and coarse trajectories were then identified and extracted automatically, then the trajectories were confirmed or edited by user, after that other user will validate those trajectories whether correct or not by voting. The essential technologies of the approach were also investigated, including trajec‐ tory location segmentation and combination algorithm, trajectory quality evaluation algorithm, and trajecto‐ ry extraction and validation workflow. A comparative experiment that takes the Harbin native clustered cas‐ es during April as a study case was conducted to evaluate the effectiveness and practicability of the proposed approach. The results show that the efficiency of the proposed approach is significantly improved one time more than the extraction method without NLP. The evaluation results of the trajectory credibility also sug‐ gest that the HCI extraction method can effectively reduce 26.34% of missing locations and wrong positioning of the trajectory automatically extracted by NLP alone. Furthermore, the validation results also suggest that there are 92.63% trajectories were assessed to be reliable, and those incorrect trajectory nodes were mainly created by the NLP algorithm rather than the hand ‐ crafted method. According to the experimental result, our proposed approach can improve the efficiency and quality of trajectories extraction effectively. Apart from that, our prototype system can also be used as a potential tool for epidemiological investigations to assist doctors or patients. [ABSTRACT FROM AUTHOR]

The emergency evacuation sign is one of the key factors that determine whether the personnel can escape safely. The rationality of its layout needs further quantitative optimization research. This paper takes the office building as the experimental area, with the help of the virtual reality eye - tracking experiment, analyzes the unreasonable layout of the directional emergency evacuation signs in the experimental area, and designs an effective modification and optimization scheme to improve the directional function of the emergency evacuation signs. Two groups of virtual eye movement evacuation experiments are designed. Each experiment consists of two experiments, in which the experimental group 1 uses the real evacuation sign layout, and the experimental group 2 uses the modified evacuation sign layout as the verification experiment. Compared with the experimental data, the evacuation time of the two experiments in experimental groups 1 and 2 was reduced by 30.28% and 30.99%, and the expected evacuation distance was reduced by 42.67% and 40.06%, so the evacuation time and the expected evacuation distance were significantly improved. The experimental results and data analysis prove the effectiveness of the modification method and scheme of directional emergency evacuation signs in the experimental area. At the same time, a new optimization method and process of directional emergency evacuation signs layout is established. [ABSTRACT FROM AUTHOR]

In this paper we present the design and implementation of a comparative experiment to study the differences in spatial cognition between head-mounted virtual reality geographic information systems (VRGIS) and desktop monitor-based virtual geographic environments, collect virtual travel behavior data from two groups of participants and explore the differences in spatial cognition. The collected virtual travel behavioral data include subjects’ self-drawn cognitive maps, movement trajectories and viewing trajectories. Then the differences in spatial cognitive performance, forgetting scores and viewing trajectories are analyzed. The following conclusions are drawn: (DThe head-mounted VRGIS group scores significantly higher than desktop monitor-based group in three levels of spatial cognition including spatial feature perception, spatial object cognition and spatial pattern cognition. (DThe two groups do not show a significant difference in forgetting scores. (DThe average rate of change in horizontal viewing direction is significantly greater in the head-mounted VRGIS group than in desktop monitor-based group. Furthermore, we discuss the internal limiting factors of spatial cognition associated with head-mounted VRGIS and its potentials for supporting virtual geographic experiment development. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience 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 pyramid model is the basis for visualization and processing of massive remote sensing data in a virtual globe system. It produces large amounts of data tiles in the process of building pyramids however, and the traditional serial CPU algorithm has difficulties satisfying requests for large images. This paper proposes a parallel global pyramid approach that exploits GPU capabilities and multi-threading to enable memory-intensive and computation-intensive tasks. A two-level decomposition strategy was developed to migrate the performance bottlenecks in data transfers among the GPU, CPU, and disk. A multi-threading strategy was used to reduce the delay between CPU and disk, and pin-memory for GPU global delay. Finally, the GPU is used to complete large-scale parallel resample computing and constructing an octree structure used to maximize reuse of data in the graphic memory. Experimental results show that the proposed method can significantly improve pyramid construction speed for large remote sensing images. [ABSTRACT FROM AUTHOR]

Copyright of Geomatics & Information Science of Wuhan University is the property of Geomatics & Information Science of Wuhan University 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.)