The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform

Guangquan Zhang - One of the best experts on this subject based on the ideXlab platform.

  • extension of similarity measures in vsm from Orthogonal Coordinate System to affine Coordinate System
    International Joint Conference on Neural Network, 2014
    Co-Authors: Junyu Xuan, Jie Lu, Guangquan Zhang
    Abstract:

    Similarity measures are the foundations of many research areas, e.g. information retrieval, recommender System and machine learning algorithms. Promoted by these application scenarios, a number of similarity measures have been proposed and proposing. In these state-of-the-art measures, vector-based representation is widely accepted based on Vector Space Model (VSM) in which an object is represented as a vector composed of its features. Then, the similarity between two objects is evaluated by the operations on two corresponding vectors, like cosine, extended jaccard, extended dice and so on. However, there is an assumption that the features are independent of each others. This assumption is apparently unrealistic, and normally, there are relations between features, i.e. the co-occurrence relations between keywords in text mining area. In this paper, a space geometry-based method is proposed to extend the VSM from the Orthogonal Coordinate System (OVSM) to affine Coordinate System (AVSM) and OVSM is proved to be a special case of AVSM. Unit Coordinate vectors of AVSM are inferred by the relations between features which are considered as angles between these unit Coordinate vectors. At last, five different similarity measures are extended from OVSM to AVSM using unit Coordinate vectors of AVSM. Within the numerous application fields of similarity measures, the task of text clustering is selected to be the evaluation criterion. Documents are represented as vectors in OVSM and AVSM, respectively. The clustering results show that AVSM outweighs the OVSM.

  • IJCNN - Extension of similarity measures in VSM: From Orthogonal Coordinate System to affine Coordinate System
    2014 International Joint Conference on Neural Networks (IJCNN), 2014
    Co-Authors: Junyu Xuan, Jie Lu, Guangquan Zhang
    Abstract:

    Similarity measures are the foundations of many research areas, e.g. information retrieval, recommender System and machine learning algorithms. Promoted by these application scenarios, a number of similarity measures have been proposed and proposing. In these state-of-the-art measures, vector-based representation is widely accepted based on Vector Space Model (VSM) in which an object is represented as a vector composed of its features. Then, the similarity between two objects is evaluated by the operations on two corresponding vectors, like cosine, extended jaccard, extended dice and so on. However, there is an assumption that the features are independent of each others. This assumption is apparently unrealistic, and normally, there are relations between features, i.e. the co-occurrence relations between keywords in text mining area. In this paper, a space geometry-based method is proposed to extend the VSM from the Orthogonal Coordinate System (OVSM) to affine Coordinate System (AVSM) and OVSM is proved to be a special case of AVSM. Unit Coordinate vectors of AVSM are inferred by the relations between features which are considered as angles between these unit Coordinate vectors. At last, five different similarity measures are extended from OVSM to AVSM using unit Coordinate vectors of AVSM. Within the numerous application fields of similarity measures, the task of text clustering is selected to be the evaluation criterion. Documents are represented as vectors in OVSM and AVSM, respectively. The clustering results show that AVSM outweighs the OVSM.

Junpeng Ma - One of the best experts on this subject based on the ideXlab platform.

  • A Fast Instantaneous Power Calculation Algorithm for Single-Phase Rectifiers Based on Arbitrary Phase-Delay Method
    IEEE Transactions on Industry Applications, 2019
    Co-Authors: Chengxiang Zhang, Siru Yu, Keteng Jiang, Xinglai Ge, Junpeng Ma
    Abstract:

    The instantaneous power for a three-phase rectifier can be calculated directly in the Orthogonal Coordinate System via Coordinate transformation. However, it is difficult to calculate the instantaneous power directly for a single-phase rectifier due to the lack of another phase. Therefore, an Orthogonal signal generator (OSG) is required to create an Orthogonal Coordinate System. Currently, conventional OSG algorithms suffer from long response time. To remedy this problem, in this paper, an arbitrary phase-delay OSG algorithm is developed and applied to the direct power control (DPC) System in the single-phase rectifiers. First, the instantaneous power theory and DPC are presented. Then, the principle of the arbitrary phase-delay OSG method is introduced and the anti-interference ability of the proposed method is analyzed. Through the dynamic response analysis, the developed algorithm brings faster response, easier implementation, and less computational burden compared with other common OSG algorithms. Finally, the validity and advancement of the proposed algorithm are verified by simulations and hardware-in-the-loop experimental tests. A comparison with conventional OSG algorithms also proves the advantages of the developed method.

  • A fast instantaneous power calculation algorithm for single-phase rectifiers based on arbitrary phase-delay method
    2017 IEEE Transportation Electrification Conference and Expo Asia-Pacific (ITEC Asia-Pacific), 2017
    Co-Authors: Chengxiang Zhang, Xinglai Ge, Junpeng Ma
    Abstract:

    The instantaneous power for three-phase rectifier can be calculated directly in the Orthogonal Coordinate System via Coordinate transformation. However, it is difficult to calculate the instantaneous power directly for single-phase rectifier due to the lack of another phase, an Orthogonal signal generator (OSG) is therefore required to create an Orthogonal Coordinate System. Currently, conventional OSG algorithms suffer from long response time, to remedy this problem, an arbitrary phase-delay OSG algorithm based on the monophase complex vector theory is developed in this paper. The developed algorithm can quickly calculate the instantaneous active power and reactive power. Through the analysis of its principle, it can be known that the developed algorithm brings faster response speed, easy implementation and less computational burden Compared with other common OSG algorithm. Finally, the proposed OSG algorithm is applied to the direct power control System in single phase rectifier and compared with other traditional OSG algorithms. The validity and advancement of the proposed algorithm are verified by simulations and hardware-in-loop experimental tests.

J I Yanchao - One of the best experts on this subject based on the ideXlab platform.

  • a simple control method of active power filter in synchronous rotating reference Orthogonal Coordinate System
    Power system technology, 2006
    Co-Authors: J I Yanchao
    Abstract:

    A simple control method of voltage source shunt active power filters is proposed in the synchronous rotating reference Orthogonal Coordinate System. By use of d-q transformation, in this control method a three phase AC System is transformed into rotating Orthogonal Coordinate System and under the transformed Coordinate System the compensating current of active power filter is controlled by PI controller to make it trace the reference current. Using the proposed control method, the control System need not to be decoupled and the System voltage fluctuation can be well controlled by only a d-q transformation module and a low-pass filter, so this method is simple and the control strategy possesses good robustness. The correctness of theoretical analysis and the feasibility of the proposed control System are verified by simulation experiments.

Junyu Xuan - One of the best experts on this subject based on the ideXlab platform.

  • extension of similarity measures in vsm from Orthogonal Coordinate System to affine Coordinate System
    International Joint Conference on Neural Network, 2014
    Co-Authors: Junyu Xuan, Jie Lu, Guangquan Zhang
    Abstract:

    Similarity measures are the foundations of many research areas, e.g. information retrieval, recommender System and machine learning algorithms. Promoted by these application scenarios, a number of similarity measures have been proposed and proposing. In these state-of-the-art measures, vector-based representation is widely accepted based on Vector Space Model (VSM) in which an object is represented as a vector composed of its features. Then, the similarity between two objects is evaluated by the operations on two corresponding vectors, like cosine, extended jaccard, extended dice and so on. However, there is an assumption that the features are independent of each others. This assumption is apparently unrealistic, and normally, there are relations between features, i.e. the co-occurrence relations between keywords in text mining area. In this paper, a space geometry-based method is proposed to extend the VSM from the Orthogonal Coordinate System (OVSM) to affine Coordinate System (AVSM) and OVSM is proved to be a special case of AVSM. Unit Coordinate vectors of AVSM are inferred by the relations between features which are considered as angles between these unit Coordinate vectors. At last, five different similarity measures are extended from OVSM to AVSM using unit Coordinate vectors of AVSM. Within the numerous application fields of similarity measures, the task of text clustering is selected to be the evaluation criterion. Documents are represented as vectors in OVSM and AVSM, respectively. The clustering results show that AVSM outweighs the OVSM.

  • IJCNN - Extension of similarity measures in VSM: From Orthogonal Coordinate System to affine Coordinate System
    2014 International Joint Conference on Neural Networks (IJCNN), 2014
    Co-Authors: Junyu Xuan, Jie Lu, Guangquan Zhang
    Abstract:

    Similarity measures are the foundations of many research areas, e.g. information retrieval, recommender System and machine learning algorithms. Promoted by these application scenarios, a number of similarity measures have been proposed and proposing. In these state-of-the-art measures, vector-based representation is widely accepted based on Vector Space Model (VSM) in which an object is represented as a vector composed of its features. Then, the similarity between two objects is evaluated by the operations on two corresponding vectors, like cosine, extended jaccard, extended dice and so on. However, there is an assumption that the features are independent of each others. This assumption is apparently unrealistic, and normally, there are relations between features, i.e. the co-occurrence relations between keywords in text mining area. In this paper, a space geometry-based method is proposed to extend the VSM from the Orthogonal Coordinate System (OVSM) to affine Coordinate System (AVSM) and OVSM is proved to be a special case of AVSM. Unit Coordinate vectors of AVSM are inferred by the relations between features which are considered as angles between these unit Coordinate vectors. At last, five different similarity measures are extended from OVSM to AVSM using unit Coordinate vectors of AVSM. Within the numerous application fields of similarity measures, the task of text clustering is selected to be the evaluation criterion. Documents are represented as vectors in OVSM and AVSM, respectively. The clustering results show that AVSM outweighs the OVSM.

John E. Johnson - One of the best experts on this subject based on the ideXlab platform.

  • virus particle explorer viper a website for virus capsid structures and their computational analyses
    Journal of Virology, 2001
    Co-Authors: Vijay S Reddy, Padmaja Natarajan, Brian Okerberg, Kevin Li, K V Damodaran, Ryan T Morton, Charles L Brooks, John E. Johnson
    Abstract:

    The number of icosahedral-capsid structures determined at a near-atomic level of resolution is growing rapidly as advances in synchrotron radiation sources, fast-readout detectors, and computer hardware and software are made. Hence, there is an increasing need to organize these mega-assemblies into a uniform and easy-to-use database. The Coordinates of the icosahedral-capsid structures deposited in the Protein Data Bank (PDB) (2) follow a variety of conventions in which the icosahedral symmetry axes are oriented differently in the Orthogonal Coordinate System. While trying to analyze the various capsid structures en masse, we became aware of the need for a database in which all capsid structures (Coordinates) are stored in a standard icosahedral orientation. Such a structural database of viral capsids would indeed facilitate the development of tools for high-throughput analyses of the virus structures. We report here the creation of a web-base (website and database) of virus structures, the Virus Particle Explorer (VIPER), which can be accessed through the World Wide Web (WWW) at the uniform resource locator (URL) http://mmtsb.scripps.edu /viper/. The organization of the VIPER database is shown in Fig. ​Fig.1.1. FIG. 1 Flow chart showing the organization of the contents of the VIPER site. The VIPER database contains the structures of viral capsids determined at a nearly atomic-level resolution. Coordinates of the capsid structures are stored in the z(2)-3-5-x(2) convention. ...