• The Journal of the Petrological Society of Korea
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• v.25 no.1
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• pp.69-83
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• 2016

Radiocarbon and OSL ages of three monogenetic volcanoes inferred to be the last volcanoes on Jeju Island, Korea were determined to identify a volcano described in historical records. The results show that the ages of those volcanoes are roughly <3.8 ka (Songaksan), >4.5 ka (Biyangdo), and <6~7 ka (Ilchulbong). Though our efforts to make a positive match between historical records and volcano-chronological dating were not successful, we make a new suggestion in this paper that two historical records of volcanic activity in 1002 and 1007 A.D. could be interpreted to be the sequential volcanic events from a single monogenetic volcano. In addition, based on a volcanological reinterpretation of historical records, we infer that the volcano described therein is most likely Mt. Songaksan, in Daejeongeup, which had early phreatomagmatic and late magmatic activities after 3.8 ka ago. Furthermore, considering the geopolitical relationship between the Goryeo Dynasty and the Tamna Kingdom, in addition with the culture of the era, this study sheds new light on the possibility that there is a time gap between the actual eruptions and the historical recording of them by ancient people.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.68-78
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• 1999

In the typical stereo vision system, when the focus points of the left and right images are mismatched or the moving object is not in the center of the image, not only the observer can be fatigued & unconscious of three-dimensional effect, but also hard to track the moving object. Therefore, the stereo object tracking system can be used to track the moving object by controlling convergence angle to minimize stereo disparity and controlling pan/tilt to locate moving object in the center of the image. In this paper, as a new approach to stereo object tracking system we introduce a stereo object tracking simulator based on the optical JTC system capable of adaptive tracking. By using this simulator, any kinds of experimental results can be predicted & analyzed and the processing if real-time implementation of stereo object tracking system is suggested through some optical experiments even if background noises exist.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.12
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• pp.99-107
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• 1998

A stereo vision system such as the structure of human's eyes has two cameras at separated positions from which we can obtain two input images and then put them together to create 3-D image. It can show more virtual effect than the conventional 2-D image system. But, the stereo image system has to control the convergence angle so that the stereo disparity could always be zero because observers can be fatigued and unconscious of stereo image in conditions that the stereo disparity is not zero for a long work. Therefore, in the paper, optical JTC system which can process adaptive tracking of a specific moving object is proposed as a new approach to keep the stereo disparity to be zero. In this method, optical JTC system obtains the values of the relative locations of a moving objects in left and right images and then these values are used for maintaining the stereo disparity to be zero. Through some optical experiments the proposed stereo vision system is proved to be insensitive to background noises and operate in real-time.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.3
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• pp.223-231
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• 2022

Spectroscopies are the most widely used for understanding the crystallographic, chemical, and physical aspects of materials; therefore, numerous commercial and non-commercial software have been introduced to help researchers better handling their spectroscopic data. However, not many researchers, especially early-stage ones, have a proper background knowledge on the choice of fitting functions and a technique for actual fitting, although the essence of such data analysis is peak fitting. In this regard, we present a practical guide for peak fitting for data analysis. We start with a basic-level theoretical background why and how a certain protocol for peak fitting works, followed by a step-by-step visualized demonstration how an actual fitting is performed. We expect that this contribution is sure to help many active researchers in the discipline of materials science better handle their spectroscopic data.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.283-295
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• 2023

With the development of sensor and satellite technology, numerous high-resolution and multi-spectral satellite images have been available. Due to their wavelength-dependent reflection, transmission, and scattering characteristics, multi-spectral satellite images can provide complementary information for earth observation. In particular, the short-wave infrared (SWIR) band can penetrate certain types of atmospheric aerosols from the benefit of the reduced Rayleigh scattering effect, which allows for a clearer view and more detailed information to be captured from hazed surfaces compared to the visible band. In this study, we proposed a multi-resolution transform-based image fusion method to combine visible and SWIR satellite images. The purpose of the fusion method is to generate a single integrated image that incorporates complementary information such as detailed background information from the visible band and land cover information in the haze region from the SWIR band. For this purpose, this study applied the Laplacian pyramid-based multi-resolution transform method, which is a representative image decomposition approach for image fusion. Additionally, we modified the multiresolution fusion method by combining a haze-guided weight map based on the prior knowledge that SWIR bands contain more information in pixels from the haze region. The proposed method was validated using very high-resolution satellite images from Worldview-3, containing multi-spectral visible and SWIR bands. The experimental data including hazed areas with limited visibility caused by smoke from wildfires was utilized to validate the penetration properties of the proposed fusion method. Both quantitative and visual evaluations were conducted using image quality assessment indices. The results showed that the bright features from the SWIR bands in the hazed areas were successfully fused into the integrated feature maps without any loss of detailed information from the visible bands.

• Journal of the Korea Computer Graphics Society
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• v.27 no.3
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• pp.31-42
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• 2021

We propose a deep learning-based method that can estimate an appropriate lighting of both indoor and outdoor images. The method consists of two networks: Crop-to-PanoLDR network and LDR-to-HDR network. The Crop-to-PanoLDR network predicts a low dynamic range (LDR) environment map from a single partially observed normal field of view image, and the LDR-to-HDR network transforms the predicted LDR image into a high dynamic range (HDR) environment map which includes the high intensity light information. The HDR environment map generated through this process is applied when rendering virtual objects in the given image. The direction of the estimated light along with ambient light illuminating the virtual object is examined to verify the effectiveness of the proposed method. For this, the results from our method are compared with those from the methods that consider either indoor images or outdoor images only. In addition, the effect of the loss function, which plays the role of classifying images into indoor or outdoor was tested and verified. Finally, a user test was conducted to compare the quality of the environment map created in this study with those created by existing research.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.6-9
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• 2009

교량, 댐, 터널 등의 대형 구조물 및 항공기 등의 기계 구조물의 경우 그 중요성과 함께 노후화 및 손상의 발생에 의한 구조물의 사고를 미연에 방지하기 위해 효과적인 건전도 평가와 손상 검색에 대한 연구가 최근 급증하고 있으며 특히 압전소자를 활용하여 구조물의 손상을 추정하는 기법들이 많이 개발되고 있다. 또한, 최근에는 압전소자와 계측기 사이를 케이블을 이용하여 연결할 경우 실제 대형 구조물에 설치 시 비효율적인 부분이 많아 무선 기반 계측시스템이 개발되고 있다. 그러나 이러한 무선 계측 시스템의 경우 압전소자의 가진 및 계측되는 데이터의 전송을 위해 별도의 전원공급이 필요하기 때문에 배터리가 포함되도록 구성되며 이럴 경우 그 수명이 제한적이기 때문에 실제 구조물에 활용 시 문제로 제기되고 있다. 이러한 배경에서 본 연구에서는 레이저를 통해 원격지의 압전소자에 무선으로 전원을 공급하여 가진시키는 시스템을 제안하였다. 압전소자를 가진시키고자 하는 임의의 파형으로 레이저를 변조(modulation)시키고 대기 중으로 전송하여, 압전소자와 연결된 광검출기(photodiode)를 통해 전기적 신호로 변환하여 최종적으로 가진시키게 된다. 이러한 시스템을 실내 실험을 통하여 구현하였으며 그 효용성을 살펴보았다.

• Journal of Energy Engineering
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• v.13 no.1
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• pp.1-11
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• 2004

Gasification is the essential technology that can meet the interim hydrogen demand of large quantity before entering the hydrogen economy. Although the hydrogen production that is based upon the pure renewable energy like wind and solar power will eventually prevail, the interim mass production of hydrogen for the next ten to twenty years will come from the technologies that can demonstrate the economic feasibility in production cost with a high potential in minimizing CO$_2$ generation and in improving plant efficiency. Particularly, feedstock such as natural gas, coal, petroleum residual oil, wastes, and biomass appears to be utilized in Korea as hydrogen source, at least during the short and medium period of time, owing to the advantage in production cost. Because one of the main reasons behind the recent hydrogen issue is the reduction requirement of CO$_2$ that would be controlled according to the climate change protocol, hydrogen production technologies must be developed to yield the minimal CO$_2$ generation.

• JOURNAL OF ELECTRICAL WORLD
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• s.306
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• pp.73-80
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• 2002

인터넷으로 대표되는 네트워크와 휴대전화의 결합으로 문자 그대로 지구규모의 디지털사회가 출연하게 되었고 사회제도와 공공의 정보기반도 그것을 반영한 형태로 변화하고 있다. 차후 디지털사회를 얼마나 안전한 것으로 만들어 가는가는 국가$\cdot$사회의 기반으로서 그 존속에 관계되는 중대한 문제이며, 기업 비즈니스에서는 사활(死活)을 건 비즈니스 문제가 되었다. 이들을 지탱하는 정보기반의 핵이 바로 암호를 중심으로 하는 정보시큐리티이다. 여기서는 현대 사회에서는 왜 암호$\cdot$정보시큐리티가 필요한가, 그 역할과 의미는 무엇인가, 어떠한 응용분야, 과제가 있는가를 전망해본다. 또한 암호란 무엇인가, 그 안전성의 의미란 무엇인가, 컴퓨터나 통신의 디지털기술과는 어떤 관련이 있는가를 역사적 배경과 최근의 동향을 바탕으로 언급하고, 현대암호의 성립, 정보시큐리티의 적용형태, 미쓰비시(삼릉)전기의 기술적 활동에 대하여 언급한다. 앞으로 전개되는 디지털 사회의 동향으로는 두 가지의 특징을 들 수 있다. 우선 휴대전화의 세계적 보급, 인터넷접속기능 장비의 발달로 현재 인터넷 유저(사용자)의 규모를 훨씬 능가하는 음성교신이 가능한 모바일인터넷의 출현이 예상된다. 모바일인터넷이 잠재적으로 갖는 안전상의 취약성을 극복하기 위해서는 암호$\cdot$정보시큐리티 기술은 보다 고도의 것이 요구된다. 또한 장래의 양자(量子)컴퓨터이 출현 등 분자레벨로 육박해 오고 있는 반도체$\cdot$광소자$\cdot$통신기술에 앞서 현재의 디지털암호에 의한 시큐리티기반의 안전성에 대한 한계가 거론되고 있다. 디지털사회의 안전성을 확보하기 위해서는 장래를 내다본 기술의 추구가 요청되고 있으며 그 대표적인 것으로 양자역학의 원리, 광기술, 디지털기술을 통합한 양자암호가 있다. 미쓰시비전기는 2000년 9월에 일본 최초로 양자암호의 실증실험에 성공하여 조기 실현화를 지향하고 있다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.346-349
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• 2003

광산 및 폐광산으로부터의 오염 및 유해영향에 대한 보고와 관심이 대두되면서 휴ㆍ폐광산에 대한 연구가 활발히 진행되고 있다. 본 연구는 경북 군위군의 고로 폐광산 주변 중 광미 및 광폐석으로 오염된 것으로 생각되어지는 하천 및 농경지에 대한 오염 정도와 분포를 규명하기 위하여 토양정밀조사를 실시하였다. 토양 오염 정밀조사 지침에 따라 총 741개의 토양 시료 분석 결과 Cu, Cd, Pb은 토양오염 우려 기준에 훨씬 미치지 못하였지만 As는 표토 및 심토 구간(0-30cm)에서 토양 오염 우려 기준 농도를 상당 수 초과하여 하천 및 농경지의 복원이 필수적임을 알 수 있었다. 합리적인 복원물량을 산출하기 위하여 배경치 농도(1.23mg/kg), 토양오염우려기준 40%농도(2.4mg/kg), 토양오염우려기준농도(6mg/kg), 토양오염대책기준농도(15mg/kg)별로 오염 등급을 나누어 오염 지도를 작성하고 각 등급별 복원목표에 따라 복원이 필요한 면적과 복원대상물량을 산출하였다. 본 연구는 오염토양의 복원을 목적으로 국내에서 최초로 실시된 대규모의 토양정밀조사라는 점에서 의미가 있으며, 이 결과는 실제 고로 폐광산지역의 복원 사업설계에 중요한 자료로 사용될 수 있다.