• Journal of Korea Multimedia Society
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• v.12 no.7
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• pp.941-946
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• 2009

As supplying of automatic surveillance or patrol systems based on image processing, the needs on object extraction technology from images increases. The extraction is more difficult when the lighting condition is changed from time to time. There are many approaches to extract objects from images excluding shadow. They have a common problem something like loss of object region according with shadow removal. In this paper a restoration method using color information of objects to complement the problem is presented. The usefulness of the method is verified using images taken from different lighting conditions and selected from well-known DB.

• The Journal of the Korea Contents Association
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• v.6 no.2
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• pp.65-74
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• 2006

The MPEG-2 video compressed bitstream is very sensitive to transmission errors due to the complex coding structure of the MPEG-2 video coding standard. If one packet is lost or received with errors, not only the current frame will be corrupted, but also errors will propagate to succeeding frames within a group of pictures. Therefore, we employ various error resilient coding/decoding techniques to protect and reduce the transmission error effects. Error concealment technique is one of them. Error concealment technique exploits spatial and temporal redundancies of the correctly received video data to conceal the corrupted video data. Motion vector recovery and compensation with the estimated motion vector is good approach to conceal the corrupted data. In this paper, we propose various error concealment algorithms based on motion vector recovery, and compare their performance to those of conventional error concealment methods.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.361-376
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• 2020

Atacamite and Verdigris were studied material scientific properties and durability that are used for traditional green pigment in traditional art painting work and Dancheong. As a result of ingrediant analysis, K-AA and K-VA identified Atacamite and Hoganite (or Verdigris) respectively. In order to find a factor of depressing the stability of pigment, we examined UV radiant exposure test, CO2/NO2 gas corrosion test and salt spray test. Salt spray test damaged both samples which were formed salt particle on the surface of the samples and it makes color disability. Furthermore, the results of gas corrosion test that both pigments change color enough to be perceived by the naked eyes showed that an air pollutant NO2 gas is also considered to be a major damage factor. In the case of K-VA, Hoganite that is main component of sample changes Tenorite with turn black after accelerated UV radiant exposure test. The consequences of the atmospheric environment effect test of the two pigments, K-VA showed relatetively weaker than K-AA.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.233-240
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• 2017

Fingerprint authentication identifies individuals based on user specific information. It is widely used as it is convenient, secure and has no risk of leakage, loss, or forgotten. However, the latent fingerprints remaining on the smart device's surface are vulnerable to smudge attacks. We analyze the usage patterns of individuals using smart device and propose methods to reconstruct damaged fingerprint images using fingerprint smudges. We examine the feasibility of smudge attacks with frequent usage situations by reconstructing fingerprint smudges collected from touch screens. Finally, we empirically verify the vulnerability of fingerprint authentication systems by showing high attack rates.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.1-14
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• 2006

To improve maritime safety, it is very important not only to make safer design and operation but also to do proper response in case of maritime casualty. The large-scaled casualties will be caused by loss of structural strength and stability due to the progressive flooding and enlargement of damage by the effect of waves and wind. To prevent foundering and structural failure, the prediction of ship motion behavior of damaged ship in wave is necessary. This paper describes the motion behavior of damaged ship in waves through theoretical and experimental studies. A time domain theoretical model of damaged ship motions and accidental flooding, which can be applied to any type of ship or arrangement and considers the effects of flooding of compartments, has been developed. The model tests have been carried out in regular and irregular waves with different wave heights and directions in ship motion basin. Those were performed for three different damaged conditions such as engine room bottom damage, side shell damage and bow visor damage of a Ro-Ro ship. Comparison of theoretical and experimental results was performed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.377-379
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• 2020

The hologram data is having a dependence on the pixel pitch of the SLM (spatial light modulator) and the wavelength of light, and the quality of the digital hologram is proportional to the unit pixel pitch and the total resolution. In addition, since each pixel has a complex value, the amount of data in the digital hologram also increases exponentially, and the size is bound to be very large. Therefore, in order to efficiently handle digital hologram files, it is essential to reduce the file size through a codec and store it. Recently, research on enhancing image quality damaged by the codec is actively underway. In this paper, the hologram image of JPEG Pleno, which is the standard hologram data, was used, and the image quality damage that occurs whenthe holographic image is encoded and decoded through the JPEG2000, AVC, and HEVC codec is enhanced with a deep learning network to find out whether the image quality can be improved. we also compare and quantitatively find out the degree of improvement in image quality.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.282-293
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• 2020

This study investigated a long-term variation trend of water quality, fish compositions, and ecological health conditions in the Gwanpyeong stream located in the nearby Daejeon metropolitan city to understand the impact of urban development projects on the aquatic ecosystem. The sampling was made in four surveys (2009, 2010, 2016, 2019) before and after urbanization. The urban development was conducted in 2008, resulting in the stream's ecological disturbance, and the stream restoration was conducted in 2012. Thus, stream monitoring was conducted to analyze the ecological trends before and after the restoration. The multi-metric models for Fish Assessment Index(FAI) and necropsy-based Health Assessment Index(HAI) were applied in the fish community and organ-level, respectively, to assess the ecological health of the stream. Minimum turbidity and chlorophyll-a(Chl-a) occurred in the mid-stream(St. 2), and this was probably due to rapid current velocity in the riffle zone. We collected 18 fish species, and the dominant species was Zacco platypus (40.6%). In 2016 immediately after the stream restoration, the relative proportions of sensitive species and insectivore species were the highest along with highest values in the species diversity and species richness index, resulting in the best condition in the ecological health, based on FAI model values. However, the ecological health, based on the FAI, became worse in the latest survey conducted in 2019. The analysis of the HAI model based on the organ-level approach showed skin erosion in the fish of upper stream, kidney defects in downstream, and the liver and gill defects observed in all sites, indicating that the anatomical health was also affected.

• Journal of Conservation Science
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• v.34 no.6
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• pp.503-515
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• 2018

Stupa of State Preceptor Jigwang at Beopcheonsa temple site, Wonju, was conserved and restored in 1957. It was necessary to assess the degree of damage to the used mortar and to provide objective data on the necessity of its removal. Therefore, the HCP(half-cell potential) measurement used in concrete fields was applied. Multi-regression analysis of HCP data, following the rapid corrosion test of the roofstone mortar used by the rebar, resulted in a high correlation of HCP values(0.86), depending on the amount of corrosion and cover depth used for the steel bar. As a result, high correlation values(0.86) for the coefficients of determination were derived. The showed that the measurement of the wet conditions -431 to -663 mV on the roofstone indicated a corrosion damage rate of 90% or more after removal and restoration.

• Journal of Chest Surgery
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• v.34 no.3
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• pp.246-251
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• 2001

심장 탈장은 심낭을 열고 전폐절제술을 시행 후 드물게 발생되는 합병증으로 수술이 끝날때나 수술직후 발생된, 44세 남자환자에서 심낭을 열고 좌측 폐를 전절제술 후 심낭 결손부위를 인공조직으로 봉합하였다. 수술이 종료될 때 심장탈장이 발생되어 개흉에 의한 응급 복원을 시행하였으나 심한 저 산소성 뇌 손상이 발생되었다.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.3
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• pp.71-78
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• 1989

A series of total loss of log carriers of G/T 4000 class which are engaged in EAST-SOUTH ASIAN route have been reported during the last decade. The casualties has been investigated in depth to draw the efficient means of safety. The results of this investigation, which are described in this paper, have been submitted to INTERNATIONAL MARITIME ORGANIZATION(IMO) by KOREAN GOVERNMENT in cooperation with the KOREAN REGISTER OF SHIPPING to request the revision of stability criteria of ship carrying timber deck cargoes.