• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.856-873
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• 2011

Reversible watermarking is an open problem in information hiding field, with embedding the encoded bit '1' or '0' into some sensitive images, such as the law enforcement, medical records and military images. The technique can retrieve the original image without distortion, after the embedded message has been extracted. Histogram-based scheme is a remarkable breakthrough in reversible watermarking schemes, in terms of high embedding capacity and low distortion. This scheme is lack of capacity control due to the requirement for embedding large-scale data, because the largest hidden capacity is decided by the amount of pixels with the peak point. In this paper, we propose a reversible watermarking scheme to enlarge the number of pixels with the peak point as large as possible. This algorithm is based on an adaptive edge-guided interpolation, furthermore, hides messages by interpolation-error, i.e. the difference between the original and interpolated image value. Simulation results compared with other state-of-the-art reversible watermarking schemes in this paper demonstrate the validity of the proposed algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.49-51
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• 2003

Developers of network games have used several prediction techniques for hiding transmission delay to support the real­time requirement of network games. Nowadays many researches that are related with network game are in progress to solve delay problems more radically, such as to propose new routers architecture and transport protocols suitable to characteristics of network game traffic. So for these advanced researches the tasks to grasp the traffic characteristics of a network game are needed. In this paper we aimed to capture the traffic of MMORPG and present the statistical analysis of measured data. The measurement and the analysis were accomplished with the server of 'Lineage' that regarded as the most successful MMORPG. Next, we have implemented a traffic generator that reflects the characteristics of MMORPG and shown that the trace generated by MMORPG traffic generator had identical characteristics with actual traffic using statistical testing method. We expect that this traffic generator can be used in many researches related with a network game.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1684-1688
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• 2005

In this paper, authentication technologies for X-ray inspection images in container merchandises are introduced and a method of authentication for X-ray inspection images is proposed. Until now, X-ray images of container merchandises have been managed without any authentication of inspection results and environments, it means that there was no any action for protection of illegal copy and counterfeiting of X-ray images from inspection results. Here, authentication identifies that who did inspect container X-ray images and, whether the container X-ray images were counterfeited or not. Our proposed algorithm indicates to put important information about X-ray inspection results on an X-ray image without affecting quality of the original image. Therefore, this paper will be useful in determining an appropriate technology and system specification for authentication of X-ray inspection images. As a result of experiment, we find that the information can be embedded to X-ray image without large degradation of image quality. Our proposed algorithm has high detection ratio by Quality 20 of JPEG attack.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.51.2-51.2
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• 2016

Hayabusa, the Japanese asteroid sample returning mission, acquired more than 1400 scientific images of its target asteroid (25143) Itokawa using the Asteroid Multi-band Imaging Camera (AMICA). It took images at a wide coverage of the phase angle a (Sun-Itokawa-Hayabusa) from $a{\sim}0^{\circ}$ to ${\sim}35^{\circ}$, providing a unique opportunity for studying the opposition effect (a sharp surge in brightness of asteroidal surface). Here we present a study of the opposition effect on Itokawa using the AMICA multi-band data. We found that (1) the opposition strength near the opposition is independent of the incident/emission angles of the light, also (2) it weakly depends on the wavelength showing the strongest surge around 0.7 um, and (3) the reflectance increases linearly at a>$1.5^{\circ}$ while nonlinearly at a<$1.5^{\circ}$ as approaching the opposition point. In particular, we noticed that the increasing rate has a correlation with the reflectance in the nonlinear domain whereas no detectable correlation with the reflectance in the linear domain. From these results, we conjecture that the coherent backscattering opposition effect is a dominant mechanism for the nonlinear opposition surge at a<$1.5^{\circ}$ while shadow hiding opposition effect is responsible for the linear opposition surge at a>$1.5^{\circ}$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.952-958
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• 2009

Recently, due to problems in terms of illegal copying of medical image and the right ownership and authentication of data, it is necessary for us to study about those problems. In this study, we propose steganography with a method of the hiding information of high-resolution in digital medical image. The proposed algorithm is one of the way that inserts secret information by protecting ROI area which is regarded as and important feature of high-resolution digital medical image. As a result, the proposed method made it possible to insert secret information of massive storage and didn't affect the imperceptibility in medical image quality based on capacity and PSNR showed the all image quality of about 33.33dB.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.765-774
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• 2004

In order to integrate heterogeneous biological information sources, it is necessary to define the view that represents unified viewpoint for the multiple sources by hiding heterogeneity of the data. We present an XML-based view definition model and show Its operating principles in designing the middleware system to integrate biological information sources. This model supports the user-defined XML view to increase flexibility in constructing the integration system and execute integrated queries on higher level ion. Based on the view-definition model, we present a wrapping model for relational database systems and web resources as well as an application program.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.72.2-72.2
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• 2018

The Opposition Effect (OE) is an enhancement of the brightness of a reflecting light as the phase angle (the Sun-target-observer angle) approaches zero. The mechanisms have been studied both theoretically and experimentally and nowadays recognized that there are two major mechanisms, namely, coherent backscattering OE (CBOE) and shadow hiding OE (SHOE). From data analyses of an S-type asteroid Itokawa taken with the Hayabusa spacecraft onboard camera, it is suggested that the CBOE would be dominant at phase angle smaller than ~ 1.4 deg, while SHOE dominates at larger phase angles (M. Lee & M. Ishiguro, under review). The study on the physical parameters which affect the OE, such as size and composition, will lead us to find a way to disentangle each of them from observation. The experiments in lab, however, faces two major difficulties: (a) the detector blocks the incident light if phase angle is nearly zero and (b) incident and emission angles must be controlled with high angular resolution to prevent blurring of OEs at different phase angles in one measurement. In this presentation, we introduce a new apparatus which has been installed at Seoul National University to investigate the OE in our lab, and summarize the initial results. It will be a valuable starting point to establish infrastructure in Korea, and will shed light on the investigation of OE physics using laboratory simulants.

• Korean Journal of Occupational Health Nursing
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• v.25 no.2
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• pp.108-117
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• 2016

Purpose: The purpose of this study was to determine the relationship between customer contact service and mental health among Korean taxi drivers. Methods: This was a secondary analysis of data collected from the 2015 Korean Working Conditions Survey. The sample included 496 taxi drivers in South Korea. The effect of customer contact service on mental health was analyzed using logistic regression analysis. The independent variables were general characteristics, working conditions, and hazardous factors in interactive service. Results: The prevalence of poor mental health was 56.3%. Taxi drivers experienced emotional involvement (17.2%), hiding feeling (32.0%), and contact with angry clients (18.3%) in their job. During the first month of their work, 33.7% experienced verbal abuse and 12.3% threats/humiliating behaviors. In bivariate analysis, verbal abuse, threats/humiliating behaviors, and physical violence were associated with mental health of taxi drivers. Multiple logistic regression analysis revealed 'emotional involvement' and 'contact with angry clients' were significant predictors of mental health. Conclusion: The findings of this study may be useful in developing intervention programs to improve the mental health of taxi drivers in South Korea.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.244-253
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• 2017

Reversible DNA watermarking is capable of continuous DNA storage and forgery prevention, and has the advantage of being able to analyze biological mutation processes by external watermarking by iterative process of concealment and restoration. In this paper, we propose a reversible DNA watermarking method based on histogram multiple shifting of noncoding DNA sequence that can prevent false start codon, maintain original sequence length, maintain high watermark capacity without biologic mutation. The proposed method transforms the non-coding region DNA sequence to the n-th code coefficients and embeds the multiple bits of the n-th code coefficients by the non-recursive histogram multiple shifting method. The multi-bit embedding process prevents the false start codon generation through comparison search between adjacent concealed nucleotide sequences. From the experimental results, it was confirmed that the proposed method has higher watermark capacity of 0.004-0.382 bpn than the conventional method and has higher watermark capacity than the additional data. Also, it was confirmed that false start codon was not generated unlike the conventional method.

• Korean Journal of Adult Nursing
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• v.15 no.1
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• pp.56-66
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• 2003

Purpose: The purpose of this study is to describe the psychological aspects of experiences of men living in a homeless shelter in Seoul. This study focused on understanding about the life of the homeless in the shelter by Phenomenological method. Method: The participants in this study were seven men who are living in a homeless shelter in Seoul. The following data were collected though the in-depth interviews and analyzed by the Phenomenological analytic method of Giorgi. Result: There are five focal significances about the life of the homeless. (1) Unplanned Life : Difficult life comes from outside situation, Freedom, The acceptance of unconsciousness life, Laziness, Unreliability, The dissolute life, No purpose to life, Relying on drinking, (2) Self-rationalization : Feeling of defeat, Give up, Desire for a support system, Lack of willingness, Anxiety, Chivalry, Falsehoods, (3) Superficial Interpersonal Relationships : Ignorance, Pressure, Discord, Hiding from one anther, avoidance. (4) A sense of devestation : Negative perspective, Mental weakness, Difficulties in employment, ambivalance with social structure, The place to escape, Complaining against the opposite sex, Sense of regret, Lack of relationship with family, The lack of self-confidence, Loss of volition (5) The Hope of new life : Realization, Desire for change, Dreaming of married life, Dependence in God Conclusion: The conclusion of this study shows that the men in the shelter had various psychological reasons for being in the homeless shelter. Further studies need to be done to validate this information and formulate ways to assist these men with their psychological needs.