http://scholars.ntou.edu.tw/handle/123456789/7 2026-08-10T19:44:23Z http://scholars.ntou.edu.tw/handle/123456789/26807 標題: Remaining Useful Life Prediction of Turbo Engine Based on CNN-BiLSTM Model With Feature Enhancement Approaches 作者: Li, Shih-Yu; Wu, Shih-Ping; Tam, Lap-Mou; Cheng, Shyi-Chyi 摘要: This article proposes a novel method for predicting the remaining useful life (RUL) of turbine engines by integrating convolutional neural networks (CNNs) and bidirectional long short-term memory (BiLSTM) frameworks with chaotic mapping (CM) and fractional-order (FO) filters (called CBCF). The method follows a sequence of CM, FO filter, CNN, and BiLSTM. CM is used for preprocessing to extract meaningful features from engine data, while the FO filter enhances image details produced by CM, contributing to more accurate RUL predictions. The enhanced images are then used as inputs to the CNN-BiLSTM model. CNN is employed to automatically extract and learn hierarchical features from the engine data through convolutional layers, capturing spatial patterns and local dependencies for more effective feature representation. BiLSTM is then used to process the time-sequenced data, integrating forward and backward network information to capture both past and future dependencies, thereby improving prediction accuracy. The commercial modular aero-propulsion system simulation (C-MAPSS) dataset, which is a benchmark dataset in this field, is utilized to evaluate the feasibility and effectiveness of the proposed method. The C-MAPSS dataset provides comprehensive data on engine degradation and has been widely used for validating RUL prediction models. Experimental results show that the integration of CM and FO filters with the CNN-BiLSTM model enhances performance, significantly reducing the root-mean-square error (RMSE) and demonstrating the potential of this approach for accurate RUL predictions. 2026-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26805 標題: Robust Nonlinear GNSS Navigation Under Heavy-Tailed Measurement Noise Using a Cauchy-Kernel Correntropy Extended Kalman Filter 作者: Jwo, Dah-Jing; Abdi, Abdirisak Daud; Chang, Yi 摘要: In urban canyon environments, the performance of global navigation satellite systems (GNSS) is severely degraded by multipath propagation, signal occlusion, and non-Gaussian measurement noise. These effects reduce positioning accuracy and service reliability. Kalman filtering and its nonlinear extensions are widely used for GNSS positioning. However, these filters rely on Gaussian noise assumptions and are formulated using the minimum mean square error (MMSE) criterion. Consequently, their performance degrades in non-Gaussian environments. Recently, filtering methods based on the maximum correntropy criterion (MCC) have been investigated as robust alternatives to MMSE-based approaches. The performance of MCC filters is strongly influenced by the choice of the kernel function. In particular, Gaussian kernel-based MCC algorithms may suffer from numerical instability under large measurement noise and strong sensitivity to kernel bandwidth selection. These limitations compromise estimation robustness and convergence stability. To address these limitations, this study proposes a Cauchy kernel-based maximum correntropy extended Kalman filter (CKMCEKF). The effectiveness of the proposed filter was validated using both simulation and real GNSS datasets. The results confirm the superior accuracy, stability, and reduced sensitivity to kernel bandwidth selection of the proposed method. 2026-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26796 標題: Regional exploitation signals inferred from a data-limited per-recruit assessment of Trichiurus japonicus in Taiwanese waters 作者: Lin, Chih-Yu; Lu, Yu-Heng; Xu, Wen-Qi; Wang, Sheng-Ping; Kitakado, Toshihide 摘要: Trichiurus japonicus is a heavily exploited coastal fishery species in the Northwest Pacific Ocean. Although Taiwan contributes less than 2% of regional landings, localized assessment is important because exploitation pressure reflects cumulative fishing mortality across jurisdictions and biological parameters may vary geographically. The lack of species-specific catch data and long-term abundance indices has prevented formal stock assessment in Taiwanese waters. To evaluate relative exploitation status under severe data constraints, agestructured and length-structured per-recruit analyses were conducted using length-frequency data collected from Taiwanese coastal fisheries between 2019 and 2023. Natural mortality was estimated using six empirical methods, and total mortality was estimated using seven catch-curve approaches, yielding forty-two fishing mortality scenarios. Length compositions were consistently dominated by small to medium individuals, and reconstructed age compositions were strongly truncated, with age-0 and age-1 fish comprising most of the catch. Current fishing mortality ranged from 0.749 to 1.483 year(-1) and exceeded conservative biological reference points, including F0.1 (0.203-0.731 year(-1)), in most scenarios. It also frequently approached or exceeded FMAX (0.385-1.887 year(-1)) and spawning potential ratio (SPR)-based thresholds. Current SPR ranged from 0.128 to 0.456 and was generally below the 40% target threshold and often near or below the 25% limit threshold. Although available data preclude a complete stock assessment, consistent signals across model structures and selectivity assumptions indicate elevated exploitation that reduces survival to older ages and limits reproductive output. These findings demonstrate that per-recruit analyses can provide useful indicators of relative exploitation under data-limited conditions and highlight the importance of incorporating localized biological indicators into future regional assessments of this transboundary resource. 2026-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26790 標題: Enhanced therapeutic effect of chemotherapy with magnetic mesoporous silica nanoparticle-mediated synergistic hyperthermia therapy 作者: Lee, Cheng-Chang; Lin, Yuan-Ting; Huang, Kai-Qun; Hwang, Jih-Shang; Lin, Hsiu-Mei 摘要: This research combined chemotherapy and magnetic hyperthermia therapy in a nano-drug delivery system based on mesoporous silica. The material exhibited dual imaging ability by adding Eu3+ ions to the silica framework with an iron oxide core, including IVIS and T2 MRI. By further grafting temperature-sensitive polymers acting as gatekeepers, the chemo drug camptothecin (CPT) was caged inside the pore until the temperature increased to 42 degrees C due to the magnetic hyperthermia effect. Moreover, tumor cells overexpress the folic acid (FA) receptor due to the need for FA molecules during their growth. It is promising that by grafting FA onto nanoparticles, tumor cells take up more material, which increases the specificity of the nanoparticles. MMSN-Eu-PEGMA-FA@CPT was successfully taken up by A549 cells, as observed with confocal laser scanning microscopy (CLSM), and exhibited great inhibition of cancer cell A549 growth. At a concentration of 25 & micro;g mL-1 under AMF, the cell viability of A549 cells was 56.2%. This is due to the synergistic effect of chemotherapy and hyperthermia therapy. 2026-01-01T00:00:00Z