• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.945-958
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• 2017

This paper proposes a novel method of reversible data hiding in JPEG images. After analyzing the JPEG features, we provide a new algorithm of selecting appropriate blocks and coefficients to carry secret messages. Instead of embedding data into the histogram of all coefficients, we propose a strategy of ordered embedding to hide data by histogram shifts in several rounds. On the recipient end, secret messages can be exactly extracted, and the original JPEG image can be losslessly recovered. Experimental results show that high embedding rate can be achieved with limited distortions. Most importantly, the marked JPEG file generated by the proposed method requires less storage size than state-of-the-art works.

• 센서학회지
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• 제22권2호
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• pp.118-123
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• 2013

Most serious stroke patients have the paralysis of their wrists, and can't use of their hands freely. But their wrists can be recovered by rehabilitation exercise. Recently, professional rehabilitation therapeutists exercise the wrists of stroke patients in hospital. But the wrists of stroke patients have not rehabilitated, because the therapeutists are much less than stroke patients in number. Therefore, the wrist bending-exercise rehabilitation robot that can measure the bending force of the patients' wrists is developed. In this paper, the three-axis force sensor was designed for the wrist bending-exercise rehabilitation robot. As a test results, the interference error of the three-axis force sensor was less than 0.85%. It is thought that the sensor can be used to measure the wrist bending force of the patient.

• 한국통신학회논문지
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• 제21권2호
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• pp.301-312
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• 1996

A new approach is presented for recovering the 3-D shape from shading image. Photometric Stereo Method (PSM) is generally based on the direct illumination. In this paper, the reflectance function is derived by introduceing the indirect diffuse illumination in PSM and then applied to hybrid reflectance model which consists fo two components; the Lambertian reflectance and the speclar reflectance. Under the hybrid reflectance model and the indirect diffuse illumination circumstances, the 3-D shape of object can be recovered from the suface normal vector extracted from the surface roughness, the surface reflectance ratio, and the intensity value of a pixel. This method is rapid because of using the reference table and simplifies the restriction condition about the reflectance function existing in prior studies. The recovery efficiency in our method is better than that in prior studies. Also, this method is applied to various types of surfaces by defining general reflectance function.

• 한국통신학회논문지
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• 제34권9A호
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• pp.649-655
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• 2009

The peak-to-average power ratio (PAPR) regrowth after the clipping is one main disadvantage of space-frequency block coded orthogonal frequency-division multiplexing (SFBC-OFDM). In this paper, we propose a relay assisted low PAPR technique for SFBC-OFDM transmission. For low PAPR at the source (mobile equipment), the relay processes SFBC encoding, which enables the source to transmit clipped single-input single-output (SISO)-OFDM signals without any increase of PAPR. Simulation results show that the clipped signal of proposed scheme is effectively recovered, and the proposed scheme achieves the diversity of SFBC without the complexity of multiple antennas at the source.

• Journal of the Korean Data and Information Science Society
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• 제26권2호
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• pp.505-516
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• 2015

We consider sparse high-dimensional linear regression models. Penalized regressions have been used as effective methods for variable selection and estimation in high-dimensional models. In penalized regressions, it is common practice to standardize variables before fitting a penalized model and then fit a penalized model with standardized variables. Finally, the estimated coefficients from a penalized model are recovered to the scale on original variables. However, these procedures produce a slightly different solution compared to the corresponding original penalized problem. In this paper, we investigate issues on the standardization of variables in penalized regressions and formulate the definition of the standardized penalized estimator. In addition, we compare the original penalized estimator with the standardized penalized estimator through simulation studies and real data analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.530-532
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• 1997

In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and a wire secure communications are investigated. A secure communication method in which the desired information signal is synthesized with the chaos signal created by the Chua's circuit is proposed and information signal is demodulated also using the Chua's circuit. The proposed method is synthesizing the desired information with the chaos circuit by adding the information signal to the chaos signal in the wire transmission system. After transmitting the synthesized signal through the wire transmission system, it is confirmed the feasibility of the secure communication from result of demodulated signals and recovered wire tapped signals.

• The Korean Journal of Ceramics
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• 제3권3호
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• pp.213-217
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• 1997

In this paper, the imparct of X-ray and plasma process-induced-damages to La doped Lead Zirconate Titanate (PLZT, (Pb1-xLa)(Zr0.5Ti0.5)O3) capacitor characteristics have been investigated from the viewpoint of gigabit scale dynamic random access memory (DRAM) applications. Plamsa damage causes asymmetric degradation on hysteresis characteristics of PLZT films. On the other hand, X-ray damage results in a symmetrical reduction of charge storage densities (Qc's) for both polarities. As La concentration increases in the films, the radiation hardness of PLZT films on X-ray and plasma exposures is improved. It is observed that the damaged devices are fully recovered by thermal annealing under oxygen ambient.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2000년도 춘계학술대회 발표논문집
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• pp.63-70
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• 2000

Brown and Proschan(1983) introduced a model for imperfect repair. At each feilure of a device, with probability p, it is repaired completely or replaced with a new device(perfect repair), and with probability 1 - p, it is returned to the functioning state, but it is only recovered to its condition just prior to failure(imperfect repair or minimal repair). In this paper, we limit the number of consecutive minimal repairs by n. We find some useful properties about ${\mu}$$\_$k/, the expected time between the k-th and the (k + 1)-st repair under the assumption that only minimal repairs are performed. Then, we assign cost to each repair and find the value of n which minimizes the long-run average cost for a fixed p under the condition that distribution F of the device is DMRL.

• 서비스연구
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• 제6권1호
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• pp.71-81
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• 2016

Cover image에 데이터를 임베딩 하여 stego-image를 생성하고, stego-image로부터 cover image를 손실 없이 복원하며 임베딩 된 데이터를 손실 없이 복원할 수 있는 가역 데이터 은닉기법의 성능을 개선하는 효율적인 기법을 제안하였다. 제안된 기법에서의 임베딩 된 데이터 크기는 이전의 기법에 비하여 더 크고, stego-image의 PSNR값은 48dB보다 더 크게 되는 것이 보장된다. 실험을 통하여 제안된 기법의 성능을 확인하였다.

• 대한한방부인과학회지
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• 제31권2호
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• pp.95-102
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• 2018

Objectives: The purpose of this paper is to report the effects of herbal medicine on spontaneous pregnancy with premature ovarian failure. Methods: The 28-year-old patient who was diagnosed premature ovarian failure was treated with herbal medicine (Hyangbujapalmul-tang-gagam), acupuncture and moxibustion. Results: After the treatment, the symptoms of premature ovarian failure such as hot flushes, sweats were improved. The patient recovered menstruation and achieved spontaneous pregnancy. Conclusions: This case shows that Korean medical treatment including herbal medicine has effect on treating infertile female with premature ovarian failure.