DSpace 集合:

Robust Nonlinear GNSS Navigation Under Heavy-Tailed Measurement Noise Using a Cauchy-Kernel Correntropy Extended Kalman Filter

2026-08-10T03:12:21Z

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.

Fin Stabilizer-Based Finite-Time H_{??/sub> Interval Type-2 Fuzzy Synthesis for Ship Rolling Motion With Bouc-Wen Hysteresis Under Imperfect Premise Matching}

2026-08-10T03:12:16Z

標題: Fin Stabilizer-Based Finite-Time H_{??/sub> Interval Type-2 Fuzzy Synthesis for Ship Rolling Motion With Bouc-Wen Hysteresis Under Imperfect Premise Matching
作者: Arumugam, Arunkumar; Chang, Wen-Jer; Lee, Yi-Chen; Lin, Yann-Horng; Li, Li; Aslam, Muhammad Shamrooz
摘要: When a ship operates at sea, it undergoes noticeable motions caused by waves and winds, with rolling being the most pronounced. Nowadays, fin stabilizers remain the most widely adopted devices for roll stabilization. However, they often exhibit hysteresis due to variations in hydrodynamic forces. To better address the control problem of ship rolling motion under nonlinearities, uncertainties, and hysteresis, this article proposes an Interval Type-2 (IT2) fuzzy controller design method that incorporates a novel Bouc-Wen (B-W) hysteresis estimator within the Takagi-Sugeno fuzzy model (TSFM) framework. The main contribution of this research lies in developing a B-W hysteresis state estimator within the IT2 TSFM framework to accurately capture the nonlinear hysteresis behavior. An IT2 fuzzy controller corresponding to the IT2 TSFM is developed using the imperfect premise matching method to improve the flexibility of controller design in practical applications. By combining with finite-time control theory, the IT2 fuzzy controller guarantees finite-time boundedness (FTB) and achieves performance index under the finite-time H-infinity criterion. According to Lyapunov theory, a new set of sufficient conditions is formulated using LMIs to guarantee the FTB for the ship rolling system. Finally, the simulation results of the nonlinear ship rolling system using the fin stabilizers are presented to verify the performance of the proposed IT2 fuzzy control approach.}

Effects of substrate temperature and substrate holder rotation speed on the characterization of (TiZrHfCr)Bx films

2026-08-10T03:12:05Z

標題: Effects of substrate temperature and substrate holder rotation speed on the characterization of (TiZrHfCr)Bx films 作者: Chen, Yung-, I; Ye, Yu-Ting; Lu, Guan-Ting; Chang, Li-Chun 摘要: (TiZrHfCr)Bx thin films were fabricated using HfB2, ZrB2, CrB2, and Ti targets in a magnetron cosputtering system onto Si wafers and SUS304 substrates. A Ti interlayer was employed to enhance the adhesion between the film and the substrate. The first batch (T batch) of (TiZrHfCr)Bx films was fabricated at substrate temperatures of 60, 200, 300, and 400 degrees C, with the substrate holder rotation speed fixed at 30 rpm. The second batch (R batch) of films was deposited at substrate holder rotation speeds of 5, 10, 15, and 30 rpm, with a substrate temperature of 400 degrees C. In the T batch, the B/(Ti + Zr + Hf + Cr) ratio of the (TiZrHfCr)Bx films varied from 1.47 to 1.39, the hardness values increased from 21.1 to 26.7 GPa, and the elastic modulus increased from 263 to 286 GPa as the substrate temperature was increased from 60 to 400 degrees C. The mechanical properties increased with increasing substrate temperature, attributed to film densification; however, the films' low stoichiometry limited the enhancement in mechanical properties. In the R batch, the hardness increased from 26.7 to 29.1 GPa, and the elastic modulus increased from 286 to 313 GPa, as the substrate holder rotation speed decreased from 30 to 5 rpm. The formation of nanoscale cyclic gradient concentrations raised the mechanical properties. The XRD analysis revealed that all the films exhibited a near-amorphous structure ascribed to under-stoichiometric compositions. Scratch test results indicated that the R5 sample, prepared at 400 degrees C with a substrate holder rotation speed of 5 rpm, exhibited the highest LC3 critical load of 41.3 N. In the wear tests, the R15 film exhibited the highest wear resistance, whereas the R10 film, under tensile stress, showed reduced wear resistance.

Shattering the Seafaring Stereotype: An Ethnographic Exploration of Gender Equality on Taiwan's Domestic Oil Tanker Fleet

2026-08-10T03:11:57Z

標題: Shattering the Seafaring Stereotype: An Ethnographic Exploration of Gender Equality on Taiwan's Domestic Oil Tanker Fleet 作者: Lee, Kimberly Hsiu-Chin; Guo, Jiunn-Liang; Chang, Wen-Jer 摘要: Despite the global hegemonic masculinity of the maritime sector, this ethnographic study investigates a 'critical anomaly' within a Taiwanese product oil tanker fleet where women occupy a majority of key navigational roles, including Master. Grounded in Feminist Standpoint Theory and the Hegelian dialectical method, the research utilises longitudinal field observations across two separate voyages (totaling 15 days) and is enriched by five in-depth interviews and one focus group with female deck officers ranging from Cadets to Masters. By centering the lived experiences of these women, the study examines the structural and behavioural factors enabling this unique gendered configuration. Findings reveal that this high female representation is the 'synthesis' of two primary constraints: uncompetitive low wages and restrictive domestic labour regulations. These factors inadvertently created a structural labour vacuum - a rupture in the masculine regime - that allowed women to enter and excel. This opportunity is sustained by the women's 'compensatory professional labor,' where exceptional competence and commitment act as a recursive validation process to neutralise gendered skepticism. The study concludes that successful penetration into masculine domains requires the alignment of sustained structural vacancies with demonstrated excellence, suggesting that industrial obstacles can be dialectically converted into strategic gateways for career advancement.

DSpace 集合:

Robust Nonlinear GNSS Navigation Under Heavy-Tailed Measurement Noise Using a Cauchy-Kernel Correntropy Extended Kalman Filter

Fin Stabilizer-Based Finite-Time H??/sub> Interval Type-2 Fuzzy Synthesis for Ship Rolling Motion With Bouc-Wen Hysteresis Under Imperfect Premise Matching

Effects of substrate temperature and substrate holder rotation speed on the characterization of (TiZrHfCr)Bx films

Shattering the Seafaring Stereotype: An Ethnographic Exploration of Gender Equality on Taiwan's Domestic Oil Tanker Fleet

Fin Stabilizer-Based Finite-Time H_{??/sub> Interval Type-2 Fuzzy Synthesis for Ship Rolling Motion With Bouc-Wen Hysteresis Under Imperfect Premise Matching}