Pub Date : 2024-08-23DOI: 10.1007/s10791-024-09457-2
Hongbo Yin, Donghua Yang, Kaiqi Zhang, Hong Gao, Jianzhong Li
In a wide variety of applications, such as indoor position selection for advertising and setting rents of different shops in a shopping mall, it is better to get the passenger flow of each room. In the indoor space, the positions of users are commonly captured by the indoor positioning system consisting of static positioning devices. And the sequence of all tracking events with the same user ordered by the corresponding time is the indoor trajectory of this user. Thus, in this paper, we define and study two essential queries named Rooms with top-k passenger flows at a Timestamp query (RkT for short) and Rooms with top-k passenger flows within a time Interval query (RkI for short), i.e., how to search rooms with top-k passenger flows at a timestamp and within a time interval in the past using indoor trajectories, respectively. For the indoor positioning system, there are only limited static positioning devices deployed in the indoor space on account of the cost. And the detection ranges of these static positioning devices only cover a small part of the indoor space. When a user is in the undetected state, there is uncertainty in its position combined with the quite complex indoor topology. Such uncertainty brings great challenges to determining the passenger flow in each room. Considering the distribution of static positioning devices, we propose a new method about how to reasonably infer where a user is in the undetected state and the corresponding probability based on its indoor trajectory and the complex indoor topology. In order to quickly retrieve the set of indoor trajectories, we propose a full Binary tree indexing indoor trajectories divided by Time intervals (BiT for short), which is built on the given set of indoor trajectories. Based on the index BiT, we propose PAT Algorithm and PAI Algorithm to efficiently process RkT and RkI queries, respectively. Extensive experiment results demonstrate superior performance of PAT Algorithm and PAI Algorithm.
在各种应用中,如广告的室内位置选择和商场内不同商铺的租金设定,最好能获得每个房间的客流量。在室内空间,用户的位置通常由静态定位设备组成的室内定位系统捕捉。而同一用户的所有跟踪事件按相应时间排序的序列就是该用户的室内轨迹。因此,在本文中,我们定义并研究了两个基本查询,分别名为 "时间戳上客流量前 k 位的房间 "查询(简称 RkT)和 "时间间隔内客流量前 k 位的房间 "查询(简称 RkI),即如何利用室内轨迹搜索过去某个时间戳上客流量前 k 位的房间和某个时间间隔内客流量前 k 位的房间。对于室内定位系统来说,由于成本原因,在室内空间部署的静态定位设备有限。而这些静态定位设备的探测范围只能覆盖室内空间的一小部分。当用户处于未检测状态时,其位置存在不确定性,再加上室内拓扑结构相当复杂。这种不确定性给确定每个房间的客流量带来了巨大挑战。考虑到静态定位设备的分布,我们提出了一种新方法,即如何根据用户的室内轨迹和复杂的室内拓扑结构,合理推断出用户处于未检测状态的位置以及相应的概率。为了快速检索室内轨迹集,我们在给定的室内轨迹集的基础上,提出了以时间间隔划分的室内轨迹全二叉树索引(简称 BiT)。基于 BiT 索引,我们提出了 PAT 算法和 PAI 算法,分别用于高效处理 RkT 和 RkI 查询。广泛的实验结果证明了 PAT 算法和 PAI 算法的卓越性能。
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Pub Date : 2024-08-19DOI: 10.1007/s10791-024-09458-1
B. Poorani, Rashmita Khilar
Polycystic ovary syndrome (PCOS) is an endocrine disorder affecting women of reproductive age characterized by the presence of multiple follicles in the ovaries that are detectable via ultrasound imaging. Early diagnosis of PCOS morphology can be challenging due to low resolution and increased speckle noise, making it difficult to identify smaller follicle boundaries. This article introduces a novel methodology, multiscale gradient-weighted oriented Otsu thresholding with sum of product fusion (MOT-SF), to address these challenges. The MOT-SF technique precisely recognizes smaller region boundaries even at lower resolutions by employing a pyramidal structure for image computation at multiple scales. Otsu's thresholding is used to segment the image, optimizing the threshold by minimizing the interclass variance at each stage. Incorporating gradient weights (λ) within classes enhances smaller boundary regions and reduces noise. Additionally, the MOT-SF method integrates a sum of product fusion strategies, combining segmented images from various scales to produce a final image that preserves both small and large PCOS structures while mitigating noise. The experimental results show that MOT-SF outperforms traditional methods such as Otsu’s thresholding and Chan-Vese models, as well as deep learning approaches such as R-CNN, in terms of computational efficiency and robustness to variations in ultrasound image quality. The MOT-SF methodology achieves an accuracy of nearly 85% and a precision of 94%, highlighting its potential to improve the detection and characterization of follicles in ultrasound images and advancing diagnostic tools in reproductive health.