25,936 research outputs found
Video retrieval based on deep convolutional neural network
Recently, with the enormous growth of online videos, fast video retrieval
research has received increasing attention. As an extension of image hashing
techniques, traditional video hashing methods mainly depend on hand-crafted
features and transform the real-valued features into binary hash codes. As
videos provide far more diverse and complex visual information than images,
extracting features from videos is much more challenging than that from images.
Therefore, high-level semantic features to represent videos are needed rather
than low-level hand-crafted methods. In this paper, a deep convolutional neural
network is proposed to extract high-level semantic features and a binary hash
function is then integrated into this framework to achieve an end-to-end
optimization. Particularly, our approach also combines triplet loss function
which preserves the relative similarity and difference of videos and
classification loss function as the optimization objective. Experiments have
been performed on two public datasets and the results demonstrate the
superiority of our proposed method compared with other state-of-the-art video
retrieval methods
Three R2R3 MYB transcription factor genes from Capsicum annuum showing differential expression during fruit ripening
Three R2R3-MYB genes, designated CaMYB1, CaMYB2 and CaMYB3, were isolated from hot pepper (Capsicum annuum. L). CaMYB1, CaMYB2 and CaMYB3 encode polypetides consisting of 340, 262 and 345 amino acids respectively, containing R2R3 domain and the signature motif specific for the interaction between MYB and bHLH proteins in the R3 domain. Phylogenetic analysis based on the deduced amino acid sequences of these three R2R3 MYB transcription factor members revealed that CaMYB1 and CaMYB2 clustered together with the anthocyanin-related subgroup of R2R3 MYB proteins from other plants, while CaMYB3 did not. CaMYBs transcripts accumulation was detected in all stages of fruit development and in flower and leaves. Three CaMYBs transcription factors showed differential expression during fruit ripening. Anthocyanin biosynthetic gene expression patterns were quite different in young leaves, flower, and the four stages of fruit development. CaMYB1 and CaMYB2 may regulate anthocyanin biosynthesis in hot pepper.Key words: Anthocyanin, Capsicum annuum, gene expression, R2R3 MYB transcription factor
Prediction of 3-d surface topography in ultra-precision machining
2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Identifying line-to-ground faulted phase in low and medium voltage AC microgrid using principal component analysis and supervised machine-learning
© 2018 IEEE. A supervised machine-learning based approach for faulted phase identification in bolted, low- A nd high-impedance line-to-ground faults using principal component analysis for feature extraction from multiple input signals is presented in this paper. DIgSILENT PowerFactory is used for simulating the underlying microgrid to obtain fault related data, while MATLAB is used for machine learning application. A 15-fold cross validation is applied to the training dataset for evaluation of different machine learning models and the results show supreme performance compared to previous methods
ADRC-based model predictive current control for PMSMs fed by three-phase four-switch inverters
© 2016 IEEE.A novel automatic disturbances rejection control (ADRC)-based model predictive current control (MPCC) strategy is developed for permanent magnet synchronous motors (PMSMs) fed by three-phase four-switch inverters, an after-fault-topology for fault-tolerant three-phase six-switch inverters. The mathematical model of a PMSM fed by a three-phase four-switch inverter is built firstly. Then the ADRC and MPCC are respectively designed, with the former being used to realize disturbance estimation and disturbance compensation while the latter being used to reduce stator current ripple and improve the quality of the torque and speed control. The resultant ADRC-based MPCC PMSM fed by an unhealthy inverter has fault-tolerant effective with dynamical performance very close to an ADRC-based MPCC PMSM fed by a healthy inverter. On the other hand, compared with PI-based MPCC PMSM fed by an unhealthy inverter, it possesses better dynamical response behavior and stronger robustness as well as smaller THD index of three-phase stator current in the presence of variation of load torque. The simulation results validate the feasibility and effectiveness of the proposed scheme
Performance analysis of full bridge, boost half bridge and half bridge topologies for application in phase shift converters
In this paper, performances of three topologies of bidirectional ports applicable to phase shift converters are compared. The proposed topologies include full bridge, half bridge and boost-half bridge that are commonly used as bi-directional port in various topologies of DC converters. The proposed analyses based on several indicators and characteristics of the topologies including reliability factor, switching loss, current ripple, cost, size, efficiency, range of power flow versus phase shift angle and control complexity. A phase shift converter based on proposed topologies was simulated using P-SIM. The analysis shows that considering all effective factors, full bridge topology provides better characteristics compared with others and can be selected for a phase shift converter. Also in some applications other topologies still remain a favorite choice. © 2013 IEEE
Moment-based fast discrete sine transforms
This paper presents a novel approach to compute discrete sine transforms (DSTs). By using a modular mapping, DSTs are approximated by the sum of a finite sequence of discrete moments. Hence, by extending our earlier technique in computing moments with an adder network only, DSTs can also be implemented easily by a systolic array primarily involving additions. The method can be applied to multidimensional DSTs as well as their inverses.published_or_final_versio
Optimization design of a voice coil actuator based on improved SOM
Voice coil actuator is a new kind of direct drive motor. It has many good performances, such as high acceleration and fast response. We present an improved sequential optimization method (SOM) and dimension reduction optimization method to design optimization a cylindrical voice coil actuator in this work. In the implementation, design of experiments (DOE) technique and Kriging approximate model are employed to improve the optimization efficiency. From the discussion, we can see that the proposed methods are very efficient. And computation cost of finite element analysis can be reduced remarkably (more than 2/3 of the cost has been saved) by the proposed methods. © 2011 IEEE
Over one hundred years of trace metal fluxes in the sediments of the Pearl River Estuary, South China
Author name used in this publication: C. C. M. IpAuthor name used in this publication: X. D. LiAuthor name used in this publication: G. ZhangAuthor name used in this publication: O. W. H. WaiAuthor name used in this publication: Y. S. Li2003-2004 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
A novel approach to fast discrete Hartley transform
The Discrete Hartley transform (DHT) is an important tool in digital signal processing. We propose a novel approach to perform DHT. We transform DHT into a form expressed in discrete moments via a modular mapping and truncating Taylor series expansion and present a completely new formula for computing DHT. We extend the use of our systolic array for fast computation of moments without any multiplications, to one that computes DHT with only a few multiplications and without any evaluations of triangular functions. The multiplication number used in our method is O(Nlog2N/log2log2N) superior to O(Nlog 2N) in the conventional FDT. The execution time of the systolic array is only O(Nlog2N/log2log2N) for 1-D DHT and O(N k) for k-D DHT (k⩾2). The systolic array consists of very simple processing elements and hence it implies an easy and potential hardware/VLSI implementation. The approach is also applicable to DHT inverses.published_or_final_versio
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