China Realtime Database Co.

Nanjing, China

China Realtime Database Co.

Nanjing, China
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Gong F.-X.,Nanjing Southeast University | Gong F.-X.,China Realtime Database Co. | Wang Q.,Nanjing Southeast University | Zhang X.-G.,Nanjing Southeast University
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2011

A hybrid GPS/TDOA(time difference of arrival algorithm)is proposed to realize location when neither GPS nor TDOA location method has positioning ability. The algorithm first makes differential operation between GPS pseudo-range equations to eliminate the constant terminal clock bias and gets GPS hyperbola equations. Then the GPS hyperbola equations are combined with TDOA hyperbola equations from cellular networks. The equations are then linearized by Taylor Series method, and the terminal location is iteratively estimated with least squares algorithm based on the linear equations. Field experiments show that more GPS pseudo-ranges will improve the location accuracy, but more TDOA measurements will degrade the location accuracy because of the big NLOS error in TDOA. It is concluded that GPS pseudo-ranges need be fully used when implementing the proposed algorithm, and TDOA measurements should be less used after ensuring location determined. In the experiments, the maximal error is 231.52 m and the root mean squared error under the best condition is 33.80 m. Such accuracy can satisfy the location applications when the precision requirement is not high but position information is indeed needed.


Gong F.,Nanjing Southeast University | Gong F.,China Realtime Database CO. | Wang Q.,Nanjing Southeast University | Zhang X.,Nanjing Southeast University
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2011

Under certain bad conditions, the number of observed GPS satellites is less than 4 for location determination and TDOA location method in cellular networks can not get enough TDOA measurements to position the mobile. In this paper, steepest decent method is used to fuse GPS pseudo-range and TDOA observations and resolve the problem; and the method can calculate the location even when neither of the two methods has positioning ability. The algorithm first differentiates between GPS pseudo-range equations to eliminate the constant terminal clock bias and gets GPS hyperbola equations. Then the GPS hyperbola equations are combined with TDOA hyperbola equations from cellular networks to define the weighted residual objective function. The optimal solution of the objective function is obtained with steepest decent method. The proposed algorithm is compared with Taylor-least squares hybrid location algorithm in field experiments. Results show that under the same condition, the proposed hybrid algorithm can achieve higher accuracy. The algorithm can perform better with more observations of GPS pseudo-range and TDOA. With 3 GPS pseudo-ranges and 3 TDOA, using the steepest decent hybrid algorithm, the average error is 17.64 m, which meets the requirements of general navigation systems.


Xue H.R.,NARI Group | Li B.,NARI Group | Ji K.,China Realtime Database Co. | Wang Z.Q.,Hangzhou Electric Power | Kong X.J.,Hangzhou Electric Power
Advanced Materials Research | Year: 2014

Power system protection is one important work which relate to security and stability of the power system. Power system relay protection is a very important part of power system and it relates to the power system security and stability. The time for fault reaction of power system protection determines the reliability of system protection and sensitivity. This paper mainly for the malfunctions of power system, we used the techniques of big data to reduce the size of the power network. We used the distributed computation and parallel computing to calculate fault calculation, topology analysis and setting calculation, which can shorten the operation time of protection equipment. At the same time, it also can improve the quality of the power and it can reduce the time harming the equipment and ensure the stable operation of the system. © (2014) Trans Tech Publications, Switzerland.


Lou P.,State Grid Corporation of China | Chen J.,State Grid Corporation of China | Lu L.M.,State Grid Corporation of China | Lv B.B.,State Grid Corporation of China | And 5 more authors.
Advanced Materials Research | Year: 2014

This paper proposed an automatic transformation technical solution for behavior control scripting languages. The solution automatically converts VBA scripting language into JavaScript scripting language. It implements automatic transformation by analyzing and comparing differences in the use of different grammatical of VBA scripts and JavaScript scripts such as data types, control structures, form controls and add-ins Etc. To ensure the accuracy and completeness of conversion the solution generates an abstract syntax tree which represents call and transitive relation between functions. Compared with the conversion tools the solution can reduce repeated manpower and improve productivity. © (2014) Trans Tech Publications, Switzerland.


Xue H.,NARI Group | Zhang K.,China Real Time Database Co. | Li B.,NARI Group | Peng C.,China Real Time Database Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

Power transformer is one of the important equipment in power system operation, correct diagnosis of the fault and defects is related to the safe operation of the entire grid. Support vector machine (SVM) can better solve the multi-classification with small sample and nonlinear characteristics, it is suitable for fault diagnosis of transformer. In this paper, we get the best global optimal solution of SVM using the cuckoo search algorithm, and get the SVM classification model with the best parameters. In this classification model, the relative content of each gas of dissolved gas analysis (DGA) is put as the evaluation indexes. The transformer fault is divided into 4 types of fault, i.e. low energy discharge, high energy discharge, mid-low temperature overheating, and high temperature overheating. Through the analysis of the existing data instance, the accuracy of the classification model using cuckoo search algorithm is better than that using grid search (GS), particle swarm optimization (PSO) and genetic algorithm (GA). ©, 2015, Power System Protection and Control Press. All right reserved.


Patent
State Grid Corporation of China, Jiangsu Electric Power Company, China Realtime Database Co. and State Grid Suzhou Power Supply Company | Date: 2013-10-21

A method and an apparatus for splitting and recovering data in a power system are provided in the invention. The method includes the steps of setting a first database and a data recovery unit in a platform layer of the power system. The first database runs in a memory of the power system and is composed of the real-time image in the memory of a grid model and static parameters of a second database. The first database is used to provide the inquiry service of the grid model and static parameters for the power system. The data recovery unit is responsible for all of the associated read-write operations with the second database. After data are written into, the data recovery unit stores the data as historical data according to the time scale characters, and writes the historical data to the second database when the second database is normal.


Renjian,China Realtime Database Co.. | Zhang K.,China Realtime Database Co.. | Zhao J.,China Realtime Database Co.. | Zheng X.,China Realtime Database Co.. | Yue M.,China Realtime Database Co..
Proceedings - 2011 International Conference on Multimedia and Signal Processing, CMSP 2011 | Year: 2011

A distributed clone selection algorithm was proposed and applied for image enhancement in the paper.The task of the distributed clone algorithm was to adapt the parameters of the image enhancement transforming function,as to enhance the contrast and detail in the image according to an objective fitness criterion. In order to improve theperformance of the clone selection algorithm, the antibodieswere separated into different groups for evolution to keep thebalance of local and global search efficiency as well as to avoid the premature convergence. Gaussian distribution, chaotic distribution, and uniform distribution were utilized in each antibody population group for mutation. Extendedexperimentation with image enhancement applicationsindicated that the proposed distributed clone selectionalgorithm achieved a great performance in optimizationprocess.© 2011 IEEE.


Wang X.,China Realtime Database Co.. | Chen J.,China Realtime Database Co.. | Zhu C.,Nanjing Institute of Industry Technology
Proceedings - 2011 International Conference on Multimedia and Signal Processing, CMSP 2011 | Year: 2011

We define a user-specific video summarization problem. With a comprehensive understanding of the challenges ( semantic and intention gaps), we simplify the problem with some assumptions, and formalize it into an optimization problem, which is intractable to solve directly. We propose a Bayesian and video hypergraph framework for video summarization. The Bayesian framework aims at analyzing users' browsing logs and inferring users' preference towards videos. There are two distinct features involved this framework, continuous streaming collaborative filtering via random walks, and modeling users' preference by Latent Dirichlet Allocation ( LDA ). LDA is also used as a dimension reduction method. With users' preference probabilities calculated in Bayesian framework, the optimization can be integrated into a video hypergraph framework in order to guarantee the coherence of video summary. We finally approximately solve the optimization problem by choosing representative clips within sub-graph partitioned by spectral clustering. Experiments show that our solution supports user-specific video summarization.© 2011 IEEE.


Zhao J.-Q.,Suzhou Power Supply Company | Ji S.-P.,China Realtime Database Co. | Qian K.-J.,Suzhou Power Supply Company | Zhou Y.-Z.,Suzhou Power Supply Company | And 4 more authors.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

This paper proposes a system to detect power system events based on relational database in power dispatching automation system and real-time database. With the developed models, the system sharply detects and analyzes abnormal grid events, such as switch trip and shock load. The real-time data is taken into consideration while doing analysis, which makes results more accurate. Taking the tripping of circuit breaker as an example, the process of fast detection of the power grid events is analyzed in detail. The proposed system has been successfully applied in the support system of smart dispatch for power systems in Suzhou. Test results show that the proposed system is able to reduce the working load of operators and can therefore provide a comprehensive protection for the secure operation of power systems. Operation records also show that the developed functions of the system have been running smoothly and can meet the requirements of power system automation of large-scale regional power systems.


Li X.-H.,China Realtime Database Co. | Li X.-H.,Jiangsu University | Zhan Y.-Z.,Jiangsu University | Ke J.,Jiangsu University | Zheng H.-W.,University of Konstanz
Computers in Human Behavior | Year: 2011

As the multimedia data increasing exponentially, how to get the video data we need efficiently become so important and urgent. In this paper, a novel method for shot retrieval is proposed, which is based on fuzzy evolutionary aiNet and hybrid features. To begin with, the fuzzy evolutionary aiNet algorithm proposed in this paper is utilized to extract key-frames in a video sequence. Meanwhile, to represent a key-frame, hybrid features of color feature, texture feature and spatial structure feature are extracted. Then, the features of key-frames in the same shot are taken as an ensemble and mapped to high dimension space by non-linear mapping, and the result obeys Gaussian distribution. Finally, shot similarity is measured by the probabilistic distance between distributions of the key-frame feature ensembles for two shots, and similar shots are retrieved effectively by using this method. Experimental results show the validity of this proposed method. © 2011 Elsevier Ltd. All rights reserved.

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