159 research outputs found
Parameter Identifiability of Ship Manoeuvring Modeling Using System Identification
To improve the feasibility of system identification in the prediction of ship manoeuvrability, several measures are presented to deal with the parameter identifiability in the parametric modeling of ship manoeuvring motion based on system identification. Drift of nonlinear hydrodynamic coefficients is explained from the point of view of regression analysis. To diminish the multicollinearity in a complicated manoeuvring model, difference method and additional signal method are employed to reconstruct the samples. Moreover, the structure of manoeuvring model is simplified based on correlation analysis. Manoeuvring simulation is performed to demonstrate the validity of the measures proposed
ΠΠ½Π°Π»ΠΈΠ· ΡΠ°Π±ΠΎΡΠΎΡΠΏΠΎΡΠΎΠ±Π½ΠΎΡΡΠΈ ΡΠΊΡΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΠΎΠΉ ΠΊΠΎΠ»ΠΎΠ½Π½Ρ
ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ ΠΏΡΠΈΡΠΈΠ½Ρ ΠΎΡΠΊΠ»ΠΎΠ½Π΅Π½ΠΈΠΉ ΡΠ°Π±ΠΎΡΡ ΡΠΊΡΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΎΠ±ΠΎΡΡΠ΄ΠΎΠ²Π°Π½ΠΈΡ ΠΎΡ ΡΠ΅Π³Π»Π°ΠΌΠ΅Π½ΡΠ½ΡΡ
Π½ΠΎΡΠΌ, ΠΏΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ Π΄Π΅ΡΠ΅ΠΊΡΡ Π² ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΡΠΊΡΠΏΠ»ΡΠ°ΡΠ°ΡΠΈΠΈ ΠΈΡΡΠ»Π΅Π΄ΡΠ΅ΠΌΠΎΠ³ΠΎ ΠΎΠ±ΠΎΡΡΠ΄ΠΎΠ²Π°Π½ΠΈΡ. ΠΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ ΡΠ°ΡΡΠΎ ΠΏΠΎΠ²ΡΠΎΡΡΡΡΠΈΡ
ΡΡ Π΄Π΅ΡΠ΅ΠΊΡΠΎΠ² ΠΏΡΠΈ ΡΠ°Π±ΠΎΡΠ΅ ΠΊΠΎΠΌΠ±ΠΈΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΡΠΊΡΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΠΎΠΉ ΠΊΠΎΠ»ΠΎΠ½Π½Ρ ΠΎΡΠΈΠ³ΠΈΠ½Π°Π»ΡΠ½ΠΎΠΉ ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠΈ. ΠΠ»Π°ΡΡΠΈΡΠΈΡΠΈΡΠΎΠ²Π°Π½Ρ ΠΎΡΠΊΠ»ΠΎΠ½Π΅Π½ΠΈΡ, ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΡ ΠΊΠΎΠ½ΠΊΠΎΡΠ΄Π°ΡΠΈΠΈ, ΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½Ρ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅ ΡΠ°ΠΊΡΠΎΡΡ, Π²Π»ΠΈΡΡΡΠΈΠ΅ Π½Π° ΠΏΡΠΎΡΠ΅ΡΡ ΡΠΊΡΡΡΠ°ΠΊΡΠΈΠΈ. Π‘ΠΎΠ·Π΄Π°Π½ Π°Π»Π³ΠΎΡΠΈΡΠΌ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ ΡΠ°Π±ΠΎΡΡ ΠΎΠ±ΠΎΡΡΠ΄ΠΎΠ²Π°Π½ΠΈΡ. Π Π°ΡΡΡΠΈΡΠ°Π½ ΡΡΠΎΠ²Π΅Π½Ρ Π΄Π΅ΡΠ΅ΠΊΡΠ½ΠΎΡΡΠΈ ΠΎΠ±ΠΎΡΡΠ΄ΠΎΠ²Π°Π½ΠΈΡ Π·Π° ΠΈΡΡΠ»Π΅Π΄ΡΠ΅ΠΌΡΠΉ ΠΏΠ΅ΡΠΈΠΎΠ΄ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ. ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠ° ΡΡΠ°ΡΠΈΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π΄Π°Π½Π½ΡΡ
ΡΠΏΠΎΡΠΎΠ±ΠΎΠΌ Π°Π½ΠΊΠ΅ΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΠΎ Π²ΡΠ±ΠΎΡΠΊΠ΅ ΡΠ°ΠΊΡΠΎΡΠΎΠ², Π²Π»ΠΈΡΡΡΠΈΡ
Π½Π° ΠΏΡΠΎΡΠ΅ΡΡ ΡΠΊΡΡΡΠ°ΠΊΡΠΈΠΈ. Π Π°Π·ΡΠ°Π±ΠΎΡΠ°Π½ ΠΌΠ΅ΡΠΎΠ΄ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ ΡΠ°Π±ΠΎΡΡ ΡΠΊΡΡΡΠ°ΠΊΡΠΎΡΠΎΠ²
Assessment of Subgrid-Scale Model Effects on Large Eddy Simulation of a Back-Step Combustor
Much progress has been made in large-eddy simulation (LES) of turbulent combustion in the last two decades, but a robust and cost-effective LES formulation is still lacking for turbulent combustion in practical configurations. In this paper, we present an assessment of different sgs models and the no sgs approach within the context of LES of a backward step combustor. Overall, the dynamic one equation eddy model behaves better than the WALE and one equation eddy models, in both reproducing main features and statistical quantities of the non-reactive and reactive flow fields. Increasing grid resolution does not necessarily improve the predictions. The results are largely dependent on whether the local flow is turbulence or combustion dominated. This implies that along with an adaptive grid refinement, an adaptive combustion model strategy is needed. In combustion simulation, applying only the first term in the series model is insufficient to well predict the dominating features and statistical quantities of the reacting flows. Thus, we suggest as future work the introduction of additional adaptive terms that will control the variance
Heat shock protein 90 in neurodegenerative diseases
Hsp90 is a molecular chaperone with important roles in regulating pathogenic transformation. In addition to its well-characterized functions in malignancy, recent evidence from several laboratories suggests a role for Hsp90 in maintaining the functional stability of neuronal proteins of aberrant capacity, whether mutated or over-activated, allowing and sustaining the accumulation of toxic aggregates. In addition, Hsp90 regulates the activity of the transcription factor heat shock factor-1 (HSF-1), the master regulator of the heat shock response, mechanism that cells use for protection when exposed to conditions of stress. These biological functions therefore propose Hsp90 inhibition as a dual therapeutic modality in neurodegenerative diseases. First, by suppressing aberrant neuronal activity, Hsp90 inhibitors may ameliorate protein aggregation and its associated toxicity. Second, by activation of HSF-1 and the subsequent induction of heat shock proteins, such as Hsp70, Hsp90 inhibitors may redirect neuronal aggregate formation, and protect against protein toxicity. This mini-review will summarize our current knowledge on Hsp90 in neurodegeneration and will focus on the potential beneficial application of Hsp90 inhibitors in neurodegenerative diseases
Towards Omni-supervised Referring Expression Segmentation
Referring Expression Segmentation (RES) is an emerging task in computer
vision, which segments the target instances in images based on text
descriptions. However, its development is plagued by the expensive segmentation
labels. To address this issue, we propose a new learning task for RES called
Omni-supervised Referring Expression Segmentation (Omni-RES), which aims to
make full use of unlabeled, fully labeled and weakly labeled data, e.g.,
referring points or grounding boxes, for efficient RES training. To accomplish
this task, we also propose a novel yet strong baseline method for Omni-RES
based on the recently popular teacher-student learning, where the weak labels
are not directly transformed into supervision signals but used as a yardstick
to select and refine high-quality pseudo-masks for teacher-student learning. To
validate the proposed Omni-RES method, we apply it to a set of state-of-the-art
RES models and conduct extensive experiments on a bunch of RES datasets. The
experimental results yield the obvious merits of Omni-RES than the
fully-supervised and semi-supervised training schemes. For instance, with only
10% fully labeled data, Omni-RES can help the base model achieve 100% fully
supervised performance, and it also outperform the semi-supervised alternative
by a large margin, e.g., +14.93% on RefCOCO and +14.95% on RefCOCO+,
respectively. More importantly, Omni-RES also enable the use of large-scale
vision-langauges like Visual Genome to facilitate low-cost RES training, and
achieve new SOTA performance of RES, e.g., 80.66 on RefCOCO
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