• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.7
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• pp.48-54
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• 2014

This paper discusses study of torque ripple minimization employing an improved TDF(torque distribution function)-based instantaneous torque control to reduce acoustic noise and vibration problem of the SRM. As the flux linkage of the SRM is a nonlinear function of phase current and rotor position, design of optimal controller for the SRM is quite complicated. Hence, an accurate mathematical model considering the nonlinearity of the SRM is required. An improved TDF based torque control has been proposed in order to reduce the toque ripple at high speed operation. Dynamic simulation using Matlab/Simulink as well as Finite Element Analysis is presented. A prototype SRM for electric vehicle traction has been manufactured to validate the experimental results comparing the dynamic simulation results.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.165-168
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• 2000

In this paper, the polyphase filter which has good ripple characteristic in the passband is proposed. This filter consists of the digital all-pass filter of parallel structure and it is the half-band filter with all zeros in unit circle. To approach easily in designing hardware, we determined the coefficients to the 16bit 1.15 format. To evaluate the performance of this filter, we analyzed the phase characteristic in each branch and simulated each filter with small coefficients. From the result, we have got to good ripple characteristic and also analyzed the fifth and the seventh, and compared them with four part : ripple, group delay, transition bandwidth, stopband attenuation.

• International Journal of Computer Science & Network Security
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• v.22 no.11
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• pp.172-176
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• 2022

Modern society unanimously recognizes the importance of education for the constructive socio-economic development of the global economy and adopts humanistic principles for building social interaction both at the state and interstate levels. The study aims at analyzing the main directions of transforming the system of higher engineering education with due regard to the actual needs of the labor market caused by the digitalization of the economy, as well as changes in the content and methodology of implementing the main socially significant processes that ensure the vital activities of modern society.

• Korea Trade Review
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• v.46 no.6
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• pp.225-238
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• 2021

This study analyzed the recent precedents of the Korean Supreme Court's Royalty and License fee on this issue and presented implications for future taxation of Royalty and License fee and digital content imports related to reproduction rights. If the price related to imported goods and the price not related to them are combined, it is necessary to revise the statutes to supplement the allocation method of royalty and license fee. In addition, if there is an agreement or a back contract for intellectual property rights through the headquarters or branch office other than the trading party, a method of inducing the importer to voluntarily report it when reporting imports should be considered. Whether Royalty and License fee is taxed or not must be determined after examining the various contract details and circumstances of the transaction.

• Archives of design research
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• v.19 no.4 s.66
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• pp.205-208
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• 2006

This work is a interactive digital art work which used the multiplex of jitter. It is an work which used a cross concept of two images. This work shows two kinds of images. One is on the wall through the gap of fluorescent lamp screen, and the other is on the fluorescent lamp screen. Two images are intercepted and comes out to the length as the multiplex of the jitter. The appearance of the spectator be recognized on the fluorescent lamp screen or on the wall, by two branch image which comes out intersecting of a length with multiplex function of the jitter. Two branch features of the image which it produces and the spectator which is input at real-time is equally divided, or in impression of juxtaposition goes in the spectator. It expresses the duplicity of the human being, with physical existence space divides the time space which we feel and there is a governing grammar which is different with each other and to express the thing it becomes. It used the image of the screen which it produces with the fluorescent lamp and cross concept.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1627-1634
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• 2021

This paper introduces a low-power compact ADC circuit for analog Convolutional filter for low-power neural network accelerator SOC. While convolutional neural network accelerators can speed up the learning and inference process, they have drawback of consuming excessive power and occupying large chip area due to large number of multiply-and-accumulate operators when implemented in complex digital circuits. To overcome these drawbacks, we implemented an analog convolutional filter that consists of an analog multiply-and-accumulate arithmetic circuit along with an ADC. This paper is focused on the design optimization of a low-power 8bit SAR ADC for the analog convolutional filter accelerator We demonstrate how to minimize the capacitor-array DAC, an important component of SAR ADC, which is three times smaller than the conventional circuit. The proposed ADC has been fabricated in CMOS 65nm process. It achieves an overall size of 1355.7㎛², power consumption of 2.6㎼ at a frequency of 100MHz, SNDR of 44.19 dB, and ENOB of 7.04bit.

• Journal of Broadcast Engineering
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• v.17 no.1
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• pp.73-80
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• 2012

Recently, medical equipments are developed and used for diagnosis or studies. In addition, demand of techniques which automatically deal with three dimensional medical images obtained from the medical equipments is growing. One of the techniques is automatic bone segmentation which is expected to enhance the diagnosis efficiency of osteoporosis, fracture, and other bone diseases. Although various researches have been proposed to solve it, they are unable to be used in practice since a size of the medical data is large and there are many low contrast boundaries with other tissues. In this paper, we present a fast and accurate automatic framework for bone segmentation based on multi-resolutions. On a low resolution step, a position of the bone is roughly detected using constrained branch and mincut which find the optimal template from the training set. Then, the segmentation and the registration are iteratively conducted on the multiple resolutions. To evaluate the performance of the proposed method, we make an experiment with femur and tibia from 50 test knee magnetic resonance images using 100 training set. The proposed method outperformed the constrained branch and mincut in aspect of segmentation accuracy and implementation time.

• Journal of Conservation Science
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• v.37 no.2
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• pp.167-178
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• 2021

For the preservation and efficient content sharing of 5 volumes (2,866 pages) of Yu Kil-Chun's book published in 1971, which provides an important collection of data for the study of modern Korean history during the late 19th century (enlightenment period of Joseon dynasty). The books were purchased and its preservation status investigated and documented electronically by scanning for permanent preservation of content and to determine the condition of preservation at the time of documentation. The degree of deterioration and damage, such as discoloration, hardening, breakage, and damage in these 50 years old modern printed books was quantified through image analysis and made attempts to visualize the damaged areas. It was observed that the degree of deterioration and damage depended on the material and the surface condition of the paper used, the degree of exposure to light, and the storage environment. The comparison of the preservation status at the time of the photographing (or scanning) and judgment as to whether or not the image under investigation was artificially modified was accomplished by comparing the electronically documented images of Seoyugyeonmun (西遊見聞) in Volume 1 of Yu Kil-Chun's works with images provided on other websites. Practical problems encountered while considering the effective preservation of electronically documented data and publicly sharing it, in the course of this study, with other academic researchers around the world were also summarized.

• Therapeutic Science for Rehabilitation
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• v.11 no.3
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• pp.65-80
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• 2022

Objective : This study examined the psychometric properties of the 12-item Coping Orientation to Problems Experienced Scale (COPE) using Rasch analysis. COPE is one of the instruments used to measure stress-coping skills. Methods : The study participants were 480 community-dwelling older adults. We tested the instrument's unidimensionality assumption using principal component analysis (PCA). Item fit was examined using infit-and-outfit mean-square (MnSq) and standardized fit statistics (ZSTD). The precision and item difficulty hierarchies of the instrument were examined. The item-difficulty hierarchy was investigated to identify the easy and difficult items. We tested differential item functioning (DIF) for sex and age groups. Results : PCA revealed that the instrument met the unidimensionality assumption (eigenvalue = 1.78). Among the 12 items, item 2 was removed because of misfit (Infit MnSq = 1.33, Infit ZSTD = 5.05, Outfit MnSq = 1.56, Outfit ZSTD = 7.15). The remaining 11 items demonstrated a conceptual item-difficulty hierarchy. The person strata value was 3.10, which is equivalent to a reliability index value of 0.81. There was no DIF for the sex and age groups (DIF contrast <0.27). Conclusion : The findings indicated that the revised COPE-11 has adequate item-level psychometric properties and can accurately measure stress coping skills.

• Imaging Science in Dentistry
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• v.33 no.2
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• pp.113-119
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• 2003

Purpose : To evaluate the relationship between morphometric analysis of bone microstructure from digital radiographic image and trabecular bone strength. Materials and Methods : One hundred eleven bone specimens with 5 mm thickness were obtained from the mandibles of 5 pigs. Digital images of specimens were taken using a direct digital intraoral radiographic system. After selection of ROI (100 × 100 pixel) within the trabecular bone, mean gray level and standard deviation were obtained. Fractal dimension and the variants of morphometric analysis (trabecular area, periphery, length of skeletonized trabeculae, number of terminal point, number of branch point) were obtained from ROI. Punch sheer strength analysis was performed using Instron (model 4465, Instron Corp., USA). The loading force (loading speed 1 mm/min) was applied to ROI of bone specimen by a 2 mm diameter punch. Stress-deformation curve was obtained from the punch sheer strength analysis and maximum stress, yield stress, Young's modulus were measured. Results: Maximum stress had a negative linear correlation with mean gray level and fractal dimension significantly (p<0.05). Yield stress had a negative linear correlation with mean gray level, periphery, fractal dimension and the length of skeletonized trabeculae significantly (p < 0.05). Young's modulus had a negative linear correlation with mean gray level and fractal dimension significantly (p < 0.05). Conclusions : The strength of cancellous bone exhibited a significantly linear relationship between mean gray level, fractal dimension and morphometric analysis. The methods described above can be easily used to evaluate bone quality clinically.