• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.169-173
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• 2016

Terahertz (THz) generation by a GaP ridge waveguide with a collinear modal phase-matching scheme based on cascaded difference frequency generation (DFG) processes is theoretically analyzed. The cascaded Stokes interaction processes and the cascaded anti-Stokes interaction processes are investigated from coupled wave equations. THz intensities and quantum conversion efficiency are calculated. Compared with non-cascaded DFG processes, THz intensities from 11-order cascaded DFG processes are increased to 5.48. The quantum conversion efficiency of 177.9% in cascaded processes can be realized, exceeding the Manley-Rowe limit.

• Journal of Power Electronics
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• v.18 no.3
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• pp.817-825
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• 2018

In this paper, a current hysteresis control with good decoupling properties for doubly-fed brushless induction machines (BDFIMs) has been proposed based on a generalized vector model. The independent control of the reactive power and speed for BDFIMs has been achieved by controlling the d-axis and the q-axis current of the control windings (CW). The proposed vector control method has been developed for the power winding (PW) flux frame. Experimental verification of a type Y180M-4 BDFIM prototype with 1/4 pole-pairs has been presented. Evidence of its good performance has been shown through experimental results.

• Journal of Korean Society for Quality Management
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• v.29 no.1
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• pp.140-159
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• 2001

The purpose of this study is to analyse the effectiveness of Quality Leadership on the Business Performance through Quality System for Manufacturing Companies in the North-east China, and research into the model of Quality Leadership is related with the Business Performance. A new questionnaire of QM based on Conti's Quality System thesis, was developed and tested. A statistical analysis of data was collected from Manufacturing Firms in the North-east China. As a result, Quality Leadership is the important drivers of Total Quality Management, and is related with the Quality System. Then, the Quality System is directly related with process, and process is also related with the Product Quality and the Business Performance. Of course, the Product Quality is directly related with the Business Performance in the end.

• Journal of Information Processing Systems
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• v.15 no.6
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• pp.1392-1405
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• 2019

The cathode voltage of aluminum electrolytic cell is relatively stable under normal conditions and fluctuates greatly when it has an anomaly. In order to detect the abnormal range of cathode voltage, an anomaly detection algorithm based on sliding window was proposed. The algorithm combines the time series segmentation linear representation method and the k-nearest neighbor local anomaly detection algorithm, which is more efficient than the direct detection of the original sequence. The algorithm first segments the cathode voltage time series, then calculates the length, the slope, and the mean of each line segment pattern, and maps them into a set of spatial objects. And then the local anomaly detection algorithm is used to detect abnormal patterns according to the local anomaly factor and the pattern length. The experimental results showed that the algorithm can effectively detect the abnormal range of cathode voltage.

• International Journal of CAD/CAM
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• v.8 no.1
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• pp.69-72
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• 2009

In this paper, we present a new shape descriptor, which is named Poisson equation-Fourier-Mellin moment Descriptor. We solve the Poisson equation in the shape area, and use the solution to get feature function, which are then integrated using Fourier-Mellin moment to represent the shape. This method develops the Poisson equation-geometric moment Descriptor proposed by Lena Gorelick, and keeps both advantages of Poisson equation-geometric moment and Fourier-Mellin moment. It is proved better than Poisson equation-geometric moment Descriptor in shape recognition and classification experiments.

• Transactions on Electrical and Electronic Materials
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• v.18 no.3
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• pp.136-140
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• 2017

The state of charge (SOC) is an important parameter in a battery-management system (BMS), and is very significant for accurately estimating the SOC of a battery. Li-ion batteries boast of excellent performance, and can only remain at their best working state by means of accurate SOC estimation that gives full play to their performances and raises their economic benefits. This paper summarizes some measures taken in SOC estimation, including the discharge experiment method, the ampere-hour integral method, the open circuit voltage method, the Kalman filter method, the neural network method, and electrochemical impedance spectroscopy (EIS. The principles of the various SOC estimation methods are introduced, and their advantages and disadvantages, as well as the working conditions adopted during these methods, are discussed and analyzed.

• Journal of Information Processing Systems
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• v.15 no.4
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• pp.748-764
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• 2019

In order to deal with the filtering delay problem of least mean square adaptive filter noise reduction algorithm and music noise problem of spectral subtraction algorithm during the speech signal processing, we combine these two algorithms and propose one novel noise reduction method, showing a strong performance on par or even better than state of the art methods. We first use the least mean square algorithm to reduce the average intensity of noise, and then add spectral subtraction algorithm to reduce remaining noise again. Experiments prove that using the spectral subtraction again after the least mean square adaptive filter algorithm overcomes shortcomings which come from the former two algorithms. Also the novel method increases the signal-to-noise ratio of original speech data and improves the final noise reduction performance.

• Current Optics and Photonics
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• v.3 no.3
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• pp.220-226
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• 2019

A novel speckle-shifting ghost imaging (SSGI) technique is proposed in this paper. This method can effectively extract the edge of an unknown object without achieving its clear ghost image beforehand. However, owing to the imaging mechanism of SSGI, the imaging result generally contains serious noise. To solve the problem, we further propose a simple and effective method to remove noise from the speckle-shifting ghost image with a connected-region labeling (CRL) algorithm. In this method, two ghost images of an object are first generated according to SSGI. A threshold and the CRL are then used to remove noise from the imaging results in turn. This method can retrieve a high-quality image of an object with fewer measurements. Numerical simulations are carried out to verify the feasibility and effectiveness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.7
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• pp.2407-2424
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• 2022

Recently, Transformer has made great progress in video retrieval tasks due to its high representation capability. For the structure of a Transformer, the cascaded self-attention modules are capable of capturing long-distance feature dependencies. However, the local feature details are likely to have deteriorated. In addition, increasing the depth of the structure is likely to produce learning bias in the learned features. In this paper, an improved Transformer structure named TransDCS (Transformer with Dynamic Convolution and Shortcut) is proposed. A Multi-head Conv-Self-Attention module is introduced to model the local dependencies and improve the efficiency of local features extraction. Meanwhile, the augmented shortcuts module based on a dual identity matrix is applied to enhance the conduction of input features, and mitigate the learning bias. The proposed model is tested on MSRVTT, LSMDC and Activity-Net benchmarks, and it surpasses all previous solutions for the video-text retrieval task. For example, on the LSMDC benchmark, a gain of about 2.3% MdR and 6.1% MnR is obtained over recently proposed multimodal-based methods.

• Journal of Korea Port Economic Association
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• v.20 no.1
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• pp.95-122
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• 2004

This study focuses on analyzing the potentiality of economic integration and the changes in logistics circumstances in Northeast Asia. So far as the changes in logistics circumstances in it, it is emphasized a complex transport system by sea and by land, according to the connection with the Railroad of South-North in Korean Peninsula and the Railroad of the Continent of Siberia. It first considers the propriety of economic integration among Korea, China and Japan in Northeast Asia. The first stage of the economic integration in Northeast Asia means it is started from contracting of FTA(Free Trade Agreement) which just agreed at the Summit Conference among Korea, China and Japan in ASEAN＋3(Korea China. Japan). At that time, the Summit Conference between the three countries have agreed to study on the propriety of FTA charging by own country's research organization. At first China has been hesitated to join with FTA in spite of high growth in his economy, because the time is not yet for it. After all, China also decided himself to participate to FTA together with Korea and Japan by reacted to the stimulus at the conference atmosphere between every country of ASEAN. The discussion on the changes in logistics circumstances also is needed to deal simultaneously with a situation in the economic integration in Northeast Asia. It is worthy to be paid our attention to the restoration of the Railroad of South-North in Korean Peninsula, which was disconnected for a long time from the dispute between South Korea and North Korea. Therefore, it needs to be investigated together with the movement of economic integration in Northeast Asia. The reaction on the restoration of the Railroad of South-North in Korean Peninsula is not only limited to the transport of trade cargo between South Korea and North Korea, but also it is reached to all of Northeast Asia, so far as to all of the area of Russia, Europe, and the other neighbor countries. Because this railroad is connected with the Railroad of the Continent of Siberia. The transport of trade cargo in Northeast Asia have been mostly depended upon the transport by sea until now. However, it would be divided into the transport by sea as well as by land from now. As its economic effect, the restoration of the Railroad of South-North in Korean Peninsula could be not only contributed to reduce the cost of logistics within South Korea and North Korea, but also within or without in Northeast Asia, Russia, and Europe. Consequently, it could be improved the power of international competitiveness of goods in Northeast Asia, according to the formation of a complex transport system together with the transport by sea and by land.