Browsing by Author "Li P"

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    A BIM and AR-based indoor navigation system for pedestrians on smartphones
    (Elsevier Inc. on behalf of the Korean Society of Civil Engineers, 2025-01) Zhang W; Li Y; Li P; Feng Z
    Indoor navigation technology, as an emerging location information service, has shown continuous growth in its application demand in recent years. In indoor navigation, indoor localization and path planning are the key factors affecting navigation quality. Most of the existing methods rely on traditional methods for indoor localization with high implementation costs. As for path planning, most methods lack the acquisition and use of semantic information, affecting navigation's practicality and intuitiveness. To alleviate the above problems, we propose a building information modeling (BIM) and augmented reality (AR)-based indoor navigation system for pedestrians that can be implemented on smartphones. Specifically, we first map a three-dimensional model space subdivided by a triangular prism to the two-dimensional plane in order to construct an indoor navigation network. Secondly, the information is analyzed using inertial navigation system technology to identify indoor positions. Then, we propose an indoor augmented reality navigation algorithm based on architectural and spatial information (IARA) algorithm for indoor path planning. Finally, we integrated the above technologies and built an indoor pedestrian navigation system based on BIM and AR technologies. Experiments in specific scenarios show that our system ensures navigation stability while obtaining results that are more relevant to the needs of pedestrians.
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    A multi-label classification model for full slice brain computerised tomography image
    (BioMed Central Ltd, 2020-11-18) Li J; Fu G; Chen Y; Li P; Liu B; Pei Y; Feng H
    BACKGROUND: Screening of the brain computerised tomography (CT) images is a primary method currently used for initial detection of patients with brain trauma or other conditions. In recent years, deep learning technique has shown remarkable advantages in the clinical practice. Researchers have attempted to use deep learning methods to detect brain diseases from CT images. Methods often used to detect diseases choose images with visible lesions from full-slice brain CT scans, which need to be labelled by doctors. This is an inaccurate method because doctors detect brain disease from a full sequence scan of CT images and one patient may have multiple concurrent conditions in practice. The method cannot take into account the dependencies between the slices and the causal relationships among various brain diseases. Moreover, labelling images slice by slice spends much time and expense. Detecting multiple diseases from full slice brain CT images is, therefore, an important research subject with practical implications. RESULTS: In this paper, we propose a model called the slice dependencies learning model (SDLM). It learns image features from a series of variable length brain CT images and slice dependencies between different slices in a set of images to predict abnormalities. The model is necessary to only label the disease reflected in the full-slice brain scan. We use the CQ500 dataset to evaluate our proposed model, which contains 1194 full sets of CT scans from a total of 491 subjects. Each set of data from one subject contains scans with one to eight different slice thicknesses and various diseases that are captured in a range of 30 to 396 slices in a set. The evaluation results present that the precision is 67.57%, the recall is 61.04%, the F1 score is 0.6412, and the areas under the receiver operating characteristic curves (AUCs) is 0.8934. CONCLUSION: The proposed model is a new architecture that uses a full-slice brain CT scan for multi-label classification, unlike the traditional methods which only classify the brain images at the slice level. It has great potential for application to multi-label detection problems, especially with regard to the brain CT images.
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    Integrating pH into the metabolic theory of ecology to predict bacterial diversity in soil
    (National Academy of Sciences, 2023-01-17) Luan L; Jiang Y; Dini-Andreote F; Crowther TW; Li P; Bahram M; Zheng J; Xu Q; Zhang X-X; Sun B; Brown J
    Microorganisms play essential roles in soil ecosystem functioning and maintenance, but methods are currently lacking for quantitative assessments of the mechanisms underlying microbial diversity patterns observed across disparate systems and scales. Here we established a quantitative model to incorporate pH into metabolic theory to capture and explain some of the unexplained variation in the relationship between temperature and soil bacterial diversity. We then tested and validated our newly developed models across multiple scales of ecological organization. At the species level, we modeled the diversification rate of the model bacterium Pseudomonas fluorescens evolving under laboratory media gradients varying in temperature and pH. At the community level, we modeled patterns of bacterial communities in paddy soils across a continental scale, which included natural gradients of pH and temperature. Last, we further extended our model at a global scale by integrating a meta-analysis comprising 870 soils collected worldwide from a wide range of ecosystems. Our results were robust in consistently predicting the distributional patterns of bacterial diversity across soil temperature and pH gradients-with model variation explaining from 7 to 66% of the variation in bacterial diversity, depending on the scale and system complexity. Together, our study represents a nexus point for the integration of soil bacterial diversity and quantitative models with the potential to be used at distinct spatiotemporal scales. By mechanistically representing pH into metabolic theory, our study enhances our capacity to explain and predict the patterns of bacterial diversity and functioning under current or future climate change scenarios.