To improve the efficiency and accuracy of kinematic calibration,the selection of measurement configurations is an important *** previous research,optimal measurement configurations mainly are selected by maximizing ob...
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To improve the efficiency and accuracy of kinematic calibration,the selection of measurement configurations is an important *** previous research,optimal measurement configurations mainly are selected by maximizing observability ***,the traditional observability indices only focus on the identification efficiency of the error parameters,while the purpose of robot kinematic calibration is to improve *** solve the inconsistency of the purpose between the observability index and calibration,the concept of the residual index to represent the residual distribution of the end effector after robot kinematic calibration with the measurement noise is *** on the quadratic form minimization of residuals,this article defines a specific residual index,O^(r),which is dimensionless and strictly better with the increase of measurement *** indices are used to select measurement configurations in the kinematic calibration of a 5-DOF 2UPU/SP-RR hybrid robot,and the calibration results show that the proposed residual index is better than the traditional indices in the accuracy and stability of the end effector residual.
This paper investigates the fault detection problem for non-uniformly sampled-data *** periodic assumption is made for the sampling *** contrast to most currently available results that are limited to strictly proper ...
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This paper investigates the fault detection problem for non-uniformly sampled-data *** periodic assumption is made for the sampling *** contrast to most currently available results that are limited to strictly proper systems,measurement noises are *** the operators introduced to capture the inter-sampling behaviors of disturbances and faults,an ofine fault detection algorithm is first derived to optimize the ratio-type design *** is then equivalently transformed into a recursive algorithm consisting of a discrete time-varying fault detection filter and the corresponding residual evaluation *** repeated computation of the parity vectors is avoided,the proposed fault detection filter can help reduce the online computational burden with comparison to the existing parity relation based fault detection method.
The mass properties information is important for the control, state estimation and fault diagnosis of the spacecraft, however, it is often difficult to be accurately measured or calculated on ground and may also chang...
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ISBN:
(纸本)9781467355339
The mass properties information is important for the control, state estimation and fault diagnosis of the spacecraft, however, it is often difficult to be accurately measured or calculated on ground and may also change in space due to the fuel consumption or structure changes. This paper proposes an improved inertia matrix identification method using the control torque input and attitude angular velocity output of the spacecraft attitude dynamic systems, which is independent of the controller form, and does not require specific command signals. Compared with the existing method, the proposed method can work well when the spacecraft rotates both slowly and fast. A numerical simulation example is presented to show the effectiveness of the method.
Multiagent deep reinforcement learning (MA-DRL) has received increasingly wide attention. Most of the existing MA-DRL algorithms, however, are still inefficient when faced with the non-stationarity due to agents chang...
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Multiagent deep reinforcement learning (MA-DRL) has received increasingly wide attention. Most of the existing MA-DRL algorithms, however, are still inefficient when faced with the non-stationarity due to agents changing behavior consistently in stochastic environments. This paper extends the weighted double estimator to multiagent domains and proposes an MA-DRL framework, named Weighted Double Deep Q-Network (WDDQN). By leveraging the weighted double estimator and the deep neural network, WDDQN can not only reduce the bias effectively but also handle scenarios with raw visual inputs. To achieve efficient cooperation in multiagent domains, we introduce a lenient reward network and scheduled replay strategy. Empirical results show that WDDQN outperforms an existing DRL algorithm (double DQN) and an MA-DRL algorithm (lenient Q-learning) regarding the averaged reward and the convergence speed and is more likely to converge to the Pareto-optimal Nash equilibrium in stochastic cooperative environments.
The endoplasmic reticulum(ER)is the major site for protein folding in eukaryotic *** homeostasis is essential for the development of an organism,whereby the unfolded protein response(UPR)within the ER is precisely ***...
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The endoplasmic reticulum(ER)is the major site for protein folding in eukaryotic *** homeostasis is essential for the development of an organism,whereby the unfolded protein response(UPR)within the ER is precisely ***-phagy is a newly identified selective autophagic pathway for removal of misfolded or unfolded proteins within the ER in mammalian ***62,a component of the translocon complex,was recently characterized as an ER-phagy receptor during the ER stress recovery phase in *** this study,we demonstrated that the Arabidopsis Sec62(AtSec62)is required for plant development and might function as an ER-phagy receptor in *** showed that AtSec62 is an ER-localized membrane protein with three transmembrane domains(TMDs)with its C-terminus facing to the ER ***62 is required for plant development because atsec62 mutants display impaired vegetative growth,abnormal pollen and decreased ***62 mutants are sensitive towards tunicamycin(TM)-induced ER stress,whereas overexpression of AtSec62 subsequently enhances stress tolerance during the ER stress recovery ***,YFP-AtSec62 colocalizes with the autophagosome marker m Ch-Atg8e in ring-like structures upon ER stress *** together,these data provide evidence for the pivotal roles of AtSec62 in plant development and ER-phagy.
0 INTRODUCTION Gabbro,crystalized mantle basaltic melts,is a common rock type on the Earth’s surface that consists of mostly clinopyroxene and *** is the dominant component of lower oceanic crust formed by slow cooli...
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0 INTRODUCTION Gabbro,crystalized mantle basaltic melts,is a common rock type on the Earth’s surface that consists of mostly clinopyroxene and *** is the dominant component of lower oceanic crust formed by slow cooling and crystallization of upwelling partial melts from the upper mantle in the mid-ocean *** observations suggest that gabbroic intrusions are also common in the continental lower crusts that have experienced extensive underplating of mantle-derived melts(Thybo and Aetemieva,2013) or exist as crystallized partial melts from mantle plume (Xiao et al.,2004).Hence the deformation of gabbro is of importance for understanding the rheology of oceanic crust and underplated continental crust.
The study delves into the expanding role of network platforms in our daily lives, encompassing various mediums like blogs, forums, online chats, and prominent social media platforms such as Facebook, Twitter, and Inst...
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The study delves into the expanding role of network platforms in our daily lives, encompassing various mediums like blogs, forums, online chats, and prominent social media platforms such as Facebook, Twitter, and Instagram. While these platforms offer avenues for self-expression and community support, they concurrently harbor negative impacts, fostering antisocial behaviors like phishing, impersonation, hate speech, cyberbullying, cyberstalking, cyberterrorism, fake news propagation, spamming, and fraud. Notably, individuals also leverage these platforms to connect with authorities and seek aid during disasters. The overarching objective of this research is to address the dual nature of network platforms by proposing innovative methodologies aimed at enhancing their positive aspects and mitigating their negative repercussions. To achieve this, the study introduces a weight learning method grounded in multi-linear attribute ranking. This approach serves to evaluate the significance of attribute combinations across all feature spaces. Additionally, a novel clustering method based on tensors is proposed to elevate the quality of clustering while effectively distinguishing selected features. The methodology incorporates a weighted average similarity matrix and optionally integrates weighted Euclidean distance, contributing to a more nuanced understanding of attribute importance. The analysis of the proposed methods yields significant findings. The weight learning method proves instrumental in discerning the importance of attribute combinations, shedding light on key aspects within feature spaces. Simultaneously, the clustering method based on tensors exhibits improved efficacy in enhancing clustering quality and feature distinction. This not only advances our understanding of attribute importance but also paves the way for more nuanced data analysis methodologies. In conclusion, this research underscores the pivotal role of network platforms in contemporary society, emp
We propose a three-cavity coupled cavity optomechanical(COM)structure with tunable system parameters and theoretically investigate the probe-light transmission *** calculation of the system’s spectra demonstrates dis...
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We propose a three-cavity coupled cavity optomechanical(COM)structure with tunable system parameters and theoretically investigate the probe-light transmission *** calculation of the system’s spectra demonstrates distinctive compound-induced transparency(CIT)characteristics,including multiple transparency windows and sideband dips,which can be explained by a coupling between optomechanically-induced transparency(OMIT)and electromagnetically-induced *** effects of optical loss(gain)in the cavity,number and topology of active cavity,tunneling ratio,and pump laser power on the CIT spectrum are evaluated and ***,the optical group delay of CIT is highly controllable and fast–slow light inter-transition can be *** proposed structure makes possible the advantageous tuning freedom and provides a potential platform for controlling light propagation and fast–slow light switching.
A new synthetic process of N-arylphthalimide and halo-containing N-arylphthalimides through the reaction between phthalic anhydride and aromatic amines bearing halo groups in [bmim][BF4] was described, ionic liquid [b...
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A new synthetic process of N-arylphthalimide and halo-containing N-arylphthalimides through the reaction between phthalic anhydride and aromatic amines bearing halo groups in [bmim][BF4] was described, ionic liquid [bmim][BF4] acted as the dual role of solvent and promoter.
Effects of various concentrations of two heavy metals, namely Cd and Cu, on gametophytes of Laminariajaponica Aresch were determined by recording morphological changes of gametophytes, determining pH values and the he...
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Effects of various concentrations of two heavy metals, namely Cd and Cu, on gametophytes of Laminariajaponica Aresch were determined by recording morphological changes of gametophytes, determining pH values and the heavy metal content of the culture solution, calculating the germination rate of sporophytes, and observing heavy metal (Cd) distribution using a fluorescence microscope. The results showed that heavy metals damaged the gametophytes, and were even lethal, and that the higher the concentration of heavy metal ions, the greater the injury to gametophytes. Gametophytes could not survive in culture solutions containing more than 100 mg/L Cd and 50 mg/L Cu and were only able to survive in culture solution containing a mixture of Cd and Cu up to a concentration of 10 mg/L, which indicates that gametophytes have a higher tolerance to Cd than Cu and that multiple heavy metal ions in solution markedly aggravate the damage to gametophytes compared with individual heavy metal ions. With increases in the concentration of the heavy metal, the burgeoning rate of sporophytes decreased acutely, and solutions containing multiple heavy metal ions caused even more marked harm to sporophytes than solutions containing a single heavy metal ion, because most sporophytes died in mixed solutions. The pH value of the culture medium dropped immediately at the beginning (the first day) of treatment, increased over the following days, and then decreased again. The pH of culture media containing multiple heavy metal ions showed greater variation than media containing a single heavy metal ion, with the extent of the decrease in pH of culture media containing multiple ions being greatest during the last period of the experiment. With increases in the concentration of heavy metals, the capacity of gametophytes to accumulate these ions increased. The blue fluorescent light emitted by the Cd-and Cd-binding protein complex existing in gametophytes in media containing different concentrations
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