• Journal of The Korean Association of Information Education
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• v.26 no.5
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• pp.353-360
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• 2022

The purpose of this study is to verify the effect of artificial intelligence storytelling education program designed to help learning artificial intelligence based on storytelling, the most important element of human intelligence, on learning flow. To this end, a 16-hour artificial intelligence education program was designed and developed, and applied over 8 weeks to 19 gifted students in 5th and 6th grades of elementary school. Artificial intelligence storytelling education program was developed in the form of teaching and learning course plans for each class and storybooks. Artificial intelligence storytelling education program application results showed significant improvements in average scores in all 9 sub-factors of learning flow, including combination of challenges and abilities, integration of behavior and consciousness, clear goal, concrete feedback, focus on task, sense of control, loss of self-consciousness, Distortion of the sense of time, and self-purpose experience. In other words, it was confirmed that artificial intelligence storytelling education program was effective in improving learning flow.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.97-105
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• 2015

Content-adaptive steganography methods embed secret messages in hard-to-model regions of covers such as complicated texture or noisy area. Content-adaptive steganalysis methods often need high dimensional features to capture more subtle relationships of local dependencies among adjacent pixels. However, these methods require many computational complexity and depend on the location of hidden message and the exploited distortion metrics. In this paper, we propose an improved steganalysis method for content-adaptive steganography to enhance detection rate with small number features. We first show that the features form the difference between DCT coefficients are useful for analyzing the content-adaptive steganography methods, and present feature extraction mehtod using first-order Markov probability for the the difference between DCT coefficients. The extracted features are used as input of ensemble classifier. Experimental results show that the proposed method outperforms previous schemes in terms of detection rates and accuracy in spite of a small number features in various content-adaptive stego images.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.109-116
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• 2014

This paper presents a high-efficiency digital class-D audio amplifier using a composite interpolation filter for portable audio devices. The proposed audio amplifier is composed of an interpolation filter, a delta-sigma modulator, and a class-D output stage. To reduce power consumption, the designed interpolation filter has an optimized composite structure that uses a direct-form symmetric and Lagrange FIR filters. Compared to the filters with homogeneous structures, the hardware cost and complexity are reduced by about half by the optimization. The coefficients of the digital delta-sigma modulator are also optimized for low power consumption. The class-D output stage has gate driver circuits to reduce shoot-through current. The implemented class-D audio amplifier exhibited a high efficiency of 87.8 % with an output power of 57 mW at a load impedance of $16{\Omega}$ and a power supply voltage of 1.8 V. An outstanding signal-to-noise ratio of 90 dB and a total harmonic distortion plus noise of 0.03 % are achieved for a single-tone input signal with a frequency of 1 kHz.

• Journal of Korean Society for Geospatial Information Science
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• v.6 no.2 s.12
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• pp.119-132
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• 1998

Much information on the terrain and the space has been depicted to maps of various form according to the map scale and the application. In Korea the base map system was made by only one projection method(Transvers Mercator projection). This is the reason to study this paper, because I think singular map projection method can't satisfy the various map scales and application. In this paper Meridian Are Length, Parallel Are Length of ellipsoid and the area of ellipsoidal surface-the length, the width and area of the map scale 1/5,000, 1/25,000, 1/5,000, 1/1,000, will be calculated and transformed to the plane length and area by Transvers Mercartor projection and Polyhedrical projection. The projection distortion which came into existence on this occasion was compared and analyzed by this Paper. And Properties on TM and Polyhedrical projection were understood. Lastly this paper intended to present suitable map projections according to the map scales and the purpose of use.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2618-2624
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• 2009

Harmonics (or distortion in wave form) has always existed in electrical power systems. It is harmless as long as its level is not substantial. However, with the recent rapid advancement of power electronics technology, so-called nonlinear loads, such as variable frequency drives for motor power/speed control, are increasingly finding their way to shipboard or offshore applications. In this paper a new approach to direct torque control (DTC) of induction motor drive is presented. In comparison with the conventional DTC methods the inverter switching frequency is constant and is dramatically increased, requiring neither any increase of the sampling frequency, nor any high frequency dither signal. The well-developed space vector modulation technique is applied to inverter control in the proposed DTC-based induction motor drive system, thereby dramatically reducing the current harmonics. As compared to the existing DTC approach with constant inverter switching frequency, the presented new approach does not invoke any concept of deadbeat control, thereby dramatically reducing the computations.

• International Area Studies Review
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• v.22 no.3
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• pp.201-219
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• 2018

This paper suggested a theoretical model, in which a security-based(secured loan, non-secured loan) credit agreement determines the form of corporate cost function through a loaning company's cost minimization in the light of a company which behaves monopolistically in product markets. Also, this paper analyzed the influence of a corporate credit agreement on market equilibrium, and economic welfare in product markets. As a result, it was found that in case a company, whose equity capital is small, implements borrowing based on a secured loan from a financial institution, the company comes to face borrowing restraints, in which the company has no choice but to get a loan within the scope of securities. When a company offers its capital goods, i.e. a production factor, as a security, there occurs a distortion to the production factor input ratio. Meanwhile, when a company comes to get a loan based on an unsecured loan, for which the interest rate is high, marginal cost rises; accordingly, the company comes to choose a credit agreement aiming at maximizing its profits. However, a company's choice of a credit agreement is not quite desirable from a consumer's viewpoint, and from the whole economic point of view; overall, such a choice is likely to aggravate economic welfare.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1671-1676
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• 2015

A unique crystallization behavior of poly(L-lactide)(PLLA)/poly(D-lactide)(PDLA) stereocomplex(SC) was observed when a PLLA/PDLA blend was subjected to the specific melting conditions. Therefore, we tried to blend PLLA and PDLA at overall composition to form PLA stereocomplexes. Moreover, impact modifier and reinforcement materials such as talc and glass fiber added to enhance the mechanical and thermal properties such as impact strength and heat distortion temperature(HDT). As a result, we got one representative result, one composite recipe with HDT $115^{\circ}C$. For more economic technology, we tried to blend PLLA and Polypropylene at overall composition and we got another representative result which could be applied to current PP/talc composites and ABS materials. The core technology of this might be the well dispersion of glass fibers into the matrix resin such as PP, PLLA and impact strength modifier.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.816-819
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• 2005

This paper proposes a coordinate correction technique using the transformation of 3D parabolic coordinate function and BP(Back Propagation) neural network in order to solve space distortion problem caused by using catadioptric camera. Although Catadioptric camera can obtain omni-directional image at all directions of 360 degrees, it makes an image distorted because of an external form of lens itself. Accordingly, To obtain transformed ideal distance coordinate information from distorted image on 3 dimensional space, we use coordinate transformation function that uses coordinates of a focus at mirror in the shape of parabolic plane and another one which projected into the shape of parabolic from input image. An error of this course is modified by BP neural network algorithm.

• Journal of the Korean Arthroscopy Society
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• v.13 no.3
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• pp.254-258
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• 2009

Tibial eminence fracture is caused by distortion, excessive flexion and extension, varus and valgus injury of the knee joint in the form of avulsion fracture. A failure over the exact anatomical reduction of fragment can lead to instability and limitation of joint motion. Recently, a variety of arthroscopic assisted reduction and fixation technique have been used. In the tibial eminence fracture, we created an arthroscopic pull-out wire fixation technique using a cannulated screw that is easy and more convenient than in the conventional technique. So we report this technique with a review of current literatures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2765-2770
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• 2014

Rear view cameras which help to park or to drive backward has been distributed through after-market, but it is inconvenient because they do not provide views of left, right and front sides. Around view monitoring(AVM) systems which can monitor around vehicle at a glance have been developed and equipped by vehicle vendor but systematic studies on these systems is lack. While the AVM system which equipped on Infiniti cars of Nissan is adequate to monitor around vehicle at a glance, it has disadvantages that additional cabling because of using analog cables is required and image quality is lowered due to EMI/EMC intervention. The around view monitoring system implemented in this paper has advantages that there are no EMI/EMC problems because of using optical network and that cabling is simple because of using plug-and-play ways. Additionally, an advantage of MOST150 network is that camera nodes and display node can be easily installed in the form of plug-and-play.