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3. FishMOT: A Simple and Effective Method for Fish Tracking Based on IoU Matching

Author

Liu, Shuo, Han, Lulu, Liu, Xiaoyang, Ren, Junli, Wang, Fang, YingLiu, and Lin, Yuanshan

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Fish tracking plays a vital role in understanding fish behavior and ecology. However, existing tracking methods face challenges in accuracy and robustness dues to morphological change of fish, occlusion and complex environment. This paper proposes FishMOT(Multiple Object Tracking for Fish), a novel fish tracking approach combining object detection and IoU matching, including basic module, interaction module and refind module. Wherein, a basic module performs target association based on IoU of detection boxes between successive frames to deal with morphological change of fish; an interaction module combines IoU of detection boxes and IoU of fish entity to handle occlusions; a refind module use spatio-temporal information uses spatio-temporal information to overcome the tracking failure resulting from the missed detection by the detector under complex environment. FishMOT reduces the computational complexity and memory consumption since it does not require complex feature extraction or identity assignment per fish, and does not need Kalman filter to predict the detection boxes of successive frame. Experimental results demonstrate FishMOT outperforms state-of-the-art multi-object trackers and specialized fish tracking tools in terms of MOTA, accuracy, computation time, memory consumption, etc.. Furthermore, the method exhibits excellent robustness and generalizability for varying environments and fish numbers. The simplified workflow and strong performance make FishMOT as a highly effective fish tracking approach. The source codes and pre-trained models are available at: https://github.com/gakkistar/FishMOT

Published
2023

25. Heterodyne analysis of high-order partial waves in attosecond photoionization of helium.

Author

Jiang, Wenyu, Roantree, Luke, Han, Lulu, Ji, Jiabao, Xu, Yidan, Zuo, Zitan, Wörner, Hans Jakob, Ueda, Kiyoshi, Brown, Andrew C., van der Hart, Hugo W., Gong, Xiaochun, and Wu, Jian

Subjects
ANGULAR distribution (Nuclear physics), RYDBERG states, WAVE analysis, PATH analysis (Statistics), ATOMS, PHOTOIONIZATION
Abstract

Partial wave analysis is key to interpretation of the photoionization of atoms and molecules on the attosecond timescale. Here we propose a heterodyne analysis approach, based on the delay-resolved anisotropy parameters to reveal the role played by high-order partial waves during photoionization. This extends the Reconstruction of Attosecond Beating By Interference of Two-photon Transitions technique into the few-photon regime. We demonstrate that even for moderate (~ 1TW/cm2) intensities, near-infrared-assisted photoionization of helium through Rydberg states results in a tiny contribution from the g0 wave, which has a significant impact on the photoelectron angular distributions via interference with the s- and d0-waves. This modulation also causes a substantial deviation in the angular distribution of the recovered spectral phase shift. Our analysis provides an efficient method to resolve isolated partial wave contributions beyond the perturbative regime, and paves the way towards understanding resonance-enhancement of partial waves. Reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) is a technique used to study photoionization of atoms occurring on attosecond timescales. Here the authors implement a heterodyne approach to detect higher-order partial-waves due to multi-photon transitions, opening a path towards analysis of the strong field regime. [ABSTRACT FROM AUTHOR]

Published
2025
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26. X‐Ray Real‐Time Imaging and Delayed Imaging from Lead‐Free Perovskite Scintillators.

Author

Mu, Dedan, Wang, Tianchi, Yuan, Junheng, Han, Lulu, Song, Hao, Yao, Shuyi, Meng, Bin, Wang, Ting, and Xu, Xuhui

Subjects
MATERIALS analysis, PEROVSKITE, MEDICAL screening, DIAGNOSTIC imaging, RADIATION, SCINTILLATORS
Abstract

X‐ray detection is vital in various fields such as medical imaging, security screening, and materials analysis. However, to meet the diverse detection requirements across different scenarios, current scintillators used for X‐ray detection encounter challenges in both immediate and delayed radiation detections. In this work, flexibly controlling trap distribution through extra ions doping into Cs2NaTbCl6 lead‐free perovskites presents a promising avenue for addressing these challenges and advancing X‐ray dose detection capabilities across diverse scientific domains. By doping Sb3+ ions into the Cs2NaTbCl6 host, the traps are significantly passivated through improved crystallinity, resulting in the suppression of afterglow behaviors and endowing the high‐resolution real‐time dynamic X‐ray detection. Additionally, the incorporation of Mn2+ into the Cs2NaTbCl6 matrix causes significant lattice distortion, leading to increased concentrations of both shallow and deep traps, effectively boosting delayed X‐ray detection efficiency. This work may provide an effective strategy for constructing efficient scintillators for the realization of multi‐environmental X‐ray imaging. [ABSTRACT FROM AUTHOR]

Published
2024
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41. Concentration and compositional controls on degradation of permafrost‐derived dissolved organic matter on the Qinghai–Tibetan Plateau.

Author

Wang, Yinghui, Wang, Yasong, Han, Lulu, McKenna, Amy M., Kellerman, Anne M., Spencer, Robert G. M., Yang, Yuanhe, and Xu, Yunping

Subjects
DISSOLVED organic matter, CARBON cycle, CHEMICAL properties, ORGANIC compounds, BIODEGRADATION
Abstract

Understanding the fate of permafrost‐derived dissolved organic matter (DOM) is critical for unraveling its role in carbon cycling. However, it remains unclear whether the high lability of permafrost‐derived DOM can be attributed to intrinsic chemical properties or elevated carbon concentrations. We investigated the dynamics of permafrost DOM from the Qinghai–Tibetan Plateau using both biodegradation and photodegradation experiments. Biodegradation and photodegradation of permafrost‐derived DOM exhibited distinct qualitative preferences for specific chemical groups (i.e., peptide‐like and aromatics, respectively). Notably, reducing the initial concentration of dissolved organic carbon (DOC) by half and a quarter resulted in shifts in biodegradable DOC content from 11.2% to 11.5% and 8.5%, respectively, accompanied by a corresponding decrease in the biodegradation rate from 0.11 to 0.06 and 0.03. This insight highlights the importance of recognizing the interplay between DOM quality and concentration and bears broader significance for our understanding of the fate of permafrost‐derived DOM in natural ecosystems. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Simulation of distributed photovoltaic power generation system

Author

Cai Gaoyuan, Li Bingbing, Liu Liqun, Zhao Zhen, Han Lulu, and Lai Youfu

Subjects
distributed photovoltaic, maximum power point tracking (mppt), inverter control, modeling and simulation, Environmental sciences, GE1-350
Abstract

Combined with the operation characteristics of photovoltaic power generation system, the mathematical model and simulation model are established, and the control strategy of bipolar inverter with wide output characteristics and the maximum power point tracking (MPPT) control method of conductance increment method are designed. The maximum power output and stable operation of distributed photovoltaic power generation system are realized. The simulation results show that the photovoltaic power generation system model established in this paper can effectively reflect the characteristics of distributed photovoltaic power generation and MPPT control. With the change of lighting conditions, the distributed photovoltaic power generation system can accurately adjust the system output, which is of great significance for the research and operation of distributed photovoltaic power generation system.

Published
2023
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50. Privacy-Preserving Travel Recommendation Based on Stay Points Over Outsourced Spatio-Temporal Data

Author

Han, Lulu, Luo, Weiqi, Lu, Rongxing, Zheng, Yandong, Yang, Anjia, Lai, Junzuo, Cheng, Yudan, and Zhang, Yongxin

Abstract

With the pervasiveness of GPS-enabled devices, mobile users can directly visit the best travel routes matching their interests and obtain a better user experience via location-based travel recommendation services. As the number of queries grows, the travel agency for location-based travel recommendations tends to outsource its recommendation services to the cloud server. Since the travel agency’s popular travel routes and raw trajectory data from mobile users contain sensitive information, privacy protection should be guaranteed. Although some schemes have been proposed to solve the privacy problems, no previous works related to the location-based recommendation are proposed over mobile users’ raw trajectories. To solve this problem, we propose a privacy-preserving travel recommendation scheme based on stay points over the raw encrypted trajectory data. Specifically, we first propose an adapted longest common subsequence computation algorithm to measure the similarity of two trajectories. Second, to support some computations under ciphertext, we design several secure two-party computation (S2PC) primitives (e.g., secure division, secure mean coordinate, and secure comparison) based on the Paillier cryptosystem. Third, we implement secure stay points extraction and adapted longest common subsequence computation protocols via these secure computation primitives. Finally, we analyze the security of our proposed scheme in the semi-honest model and show that the privacy of mobile users’ trajectories, query results, and the travel agency’s popular travel routes are well protected. Meanwhile, we evaluate the performance of each secure computation primitive and conduct extensive experiments on synthetic datasets, and the experimental results show that our scheme is practical in the real applications.

Published
2024
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