• Journal of the Korea Institute of Information Security & Cryptology
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• 제30권4호
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• pp.559-572
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• 2020

As internet technology advances, users can share content online, and many sharing services exist. According to a recently published digital forensic study, when playing an online streaming service, you can restore the played video by reconstructing the Chrome cache file left on local device such as a PC. This can be seen as evidence that the user watched illegal video content. From a different point of view, copyright infringement occurs when a malicious user restores video stream and share it to another site. In this paper, we selected 23 online streaming services that are widely used both at home and abroad. After streaming videos, we tested whether we can recover original video using cache files stored on the PC or not. As a result, the paper found that in most sites we can restore the original video by reconstructing cache files. Furthermore, this study also discussed methodologies for preventing copyright infringement in online streaming service.

• Journal of the Korean Institute of Telematics and Electronics S
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• 제35S권12호
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• pp.46-54
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• 1998

In this paper we propose a fast adaptive image restoration filter using DCT-based block classification for reducing block artifacts in compressed images. In order to efficiently reduce block artifacts, edge direction of each block is classified by using the DCT coefficients, and the constrained least square (CLS) on the observation that the quantization operation in a series of coding process is a nonlinear and many-to-one mapping operator. And then we propose an approximated version of constrained optimization technique as a restoration process for removing the nonlinear and space-varying degradation operator. For real-time implementation, the proposed restoration filter can be realized in the form of a truncated FIR filter, which is suitable for postprocessing reconstructed images in HDTV, DVD, or video conference systems.

• Journal of the Korea Society of Computer and Information
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• 제10권2호
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• pp.97-104
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• 2005

Caption texts frequently inserted in a manufactured video image for helping an understanding of the TV audience. In the movies. replacement of the caption texts can be achieved without any loss of an original image, because the caption texts have their own track in the films. To replace the caption texts in early methods. the new texts have been inserted the caption area in the video images, which is filled a certain color for removing established caption texts. However, the use of these methods could be lost the original images in the caption area, so it is a Problematic method to the TV audience. In this Paper, we propose a new method for replacing the caption text after recovering original image in the caption area. In the experiments. the results in the complex images show some distortion after recovering original images, but most results show a good caption text with the recovered image. As such, this new method is effectively demonstrated to replace the caption texts in video images.

• Journal of IKEEE
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• 제19권1호
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• pp.33-40
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• 2015

Inverse problem in electrical impedance tomography (EIT) is highly ill-posed therefore prior information is used to mitigate the ill-posedness. Regularization methods are often adopted in solving EIT inverse problem to have satisfactory reconstruction performance. In solving the EIT inverse problem, iterative Gauss-Newton method is generally used due to its accuracy and fast convergence. However, its performance is still suboptimal and mainly depends on the selection of regularization parameter. Although, there are few methods available to determine the regularization parameter such as L-curve method they are sometimes not applicable for all cases. Moreover, regularization parameter is a scalar and it is fixed during iteration process. Therefore, in this paper, a novel method is used to determine the regularization parameter to improve reconstruction performance. Conductivity norm is calculated at each iteration step and it used to obtain the regularization parameter which is a diagonal matrix in this case. The proposed method is applied to human thorax imaging and the reconstruction performance is compared with traditional methods. From numerical results, improved performance of proposed method is seen as compared to conventional methods.

• Composites Research
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• 제29권1호
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• pp.16-23
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• 2016

In this paper, numerical results of sectional analysis, stress recovery and energy release rate were compared with the results of VABS, 3-D FEM through the blade analysis library. The result of stress recovery analysis for one-dimensional model including the stiffness matrix is compared with stress results of three-dimensional FEM. We discuss the configuration of the blade analysis library and compare verifications of numerical analysis results of VABS. Blade analysis library through dimensional reduction and stress recovery is intended to be utilized in conjunction with pre- and post-processing of the analysis program of the composite blade, high-altitude uav's wing, wind blades and tilt rotor blade.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2017년도 학술발표회
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• pp.6-6
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• 2017

본 연구의 목적은 독립적으로 수행되어진 하천 복원 가치추정 선행연구들을 대상으로 메타회귀분석을 활용한 편익이전을 제시함으로써, 편익이전의 타당성 및 적용 가능성을 검토하는 데 있다. 문헌검색을 통해 '하천 가치평가', '하천 가치', '물 환경 가치추정', '하천 편익' 등에 관한 자료를 수집하였으며, 총 60편의 연구를 수집했다. 그 중 중복된 연구를 제외하고 가치추정 단위를 '원/년/가구'로 통일함으로써 51편의 연구를 분석에 사용했으며, 90개의 가치 추정치가 실증분석에 사용되었다. 본 연구는 국내에서 수행된 하천 복원 가치 추정연구를 집대성하여 DB를 구축하고 요약통계량을 중심으로 선행연구 결과를 기술하였으며, 메타회귀분석을 실시한 후, policy site의 특성과 조건에 맞게 함수를 조정하고, 조정된 함수를 사용하여 policy site의 가치를 예측하였다. 종속변수로는 총 가치(원/년/가구, 2015년 불변가격)가, 독립변수로는 하천유형, 위치, 규모, 환경 서비스특성, 그리고 방법론 특성, 지불형태, 대상지 사회경제적 특성 변수들이 포함되었다. 모형의 추정결과 조정된 값은.420으로써 종속변수 총변이의 42.0%를 모형이 설명하는 것으로 나타났다. 메타회귀분석을 통해 본류에서 멀어지는 소규모하천일수록 하천의 경제적 가치를 더 크게 느끼는 것으로 나타났으며, 전체적인 영향력 크기를 고려해 본다면 하천을 복원할 때 수질정화기능, 서식지기능, 이수기능, 치수기능, 여가 및 수변공간으로의 기능 순으로 고려하는 것이 하천의 가치를 보다 높일 수 있을 것으로 보였다. 또한 지불방법은 매월, 인당 지불하는 것으로 제시할 때 경제적 가치 추정치를 높일 수 있는 것으로 해석되었다. 모델추정 결과를 활용한 함수이전에서는 만경강의 특성을 반영하고 조정함으로써 만경강의 가치를 추정하였으며, 모형으로부터 얻은 만경강 가치 예측치는 가구당 매년 41,214원으로 추정되었다. 본 연구의 메타회귀분석은 선행연구를 객관적으로 종합할 수 있는 분석의 틀로서 충분한 활용 타당성이 인정되는 것으로 보이며, 편익이전 시에 policy site의 자원특성과 조건에 맞춰 함수를 조정하여 예측치를 제시함으로써 메타회귀분석 함수이전의 융통성을 보여주었다. 이에 메타회귀분석을 통한 편익이전은 타당성 및 적용 가능성 측면에서 긍정적으로 판단된다.

• The Journal of the Korea Contents Association
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• 제20권7호
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• pp.56-65
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• 2020

The purpose of this research is to study the excellence and originality of the Joseon artillery(Jungwan-gu) through an effective restoration. Jungwan-gu that was used during the Japanese Invasion of Korea in 1592 was able to maintain its maritime dominance based on cutting-edge technology of its time. Joeson artillery(Jungwan-gu) was used in major naval/land battles during the Japanese Invasion of Korea in 1592 and is an important cultural heritage that provides a glimpse into Joeson people's will to defend the nation from foreign invasion. For further historical verification such as operational method of Jungwan-gu, extensive research in various fields including size, proportions, structure, materials, and casting method were required. Accordingly, for a more effective research on Jungwan-gu, cutting-edge technologies such as 3D scanning and 3D printing were utilized. Firstly, 3D scanning, modeling, and printing technology were applied to identify the morphological characteristics of Jungwan-gu. Through this, we were able to reach our research objective of identifying the size, internal structure, and proportionality of Jungwan-gu. In addition, by studying the form, operation, casting methods, and other characteristics, the restoration of Jungwan-gu provided us with an important opportunity to verify the dominance and originality of the Joeson era's science and technology during the Japanese Invasion of 1592. This reaserch subject participated in the "4th 3D printing BIZCON Contest" and won the Minister Prize of Science and Technology Information and Communication.

• Journal of Navigation and Port Research
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• 제43권6호
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• pp.444-449
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• 2019

The "Standard on Cargo Stowage and Securing" implemented to safely stow and secure the cargo of international shipping vessels and domestic car ferries, has also been applied to general cargo ships transported between domestic ports since J anuary 2018. As a result, a new type of cargo, such as a non-standardized steel box transported by general cargo ships to major ports in Korea from Jeju Island in Korea, must be factored as the method of safe stowage and securing according to the legal classification of cargo. This study analyzed the legal status of a steel box by analyzing the actual size, shape of steel box through field verification, collection of data from relevant agencies and finally proposed the methods of safe stowage and securing for a steel box in the cargo holds of general cargo ships. According to the relevant domestic laws and international regulations, steel boxes could be classified as pallette boxes with protective outer packing, a type of non-standardized cargo. Additionally, when a steel box is loaded into the cargo hold of general cargo ships, a method of loading and transporting them must be factored so that there is no gap in the cargo hold of ships. Verification of the safety of the tightly loading and transportation measures in the reviewed cargo hold was verified through safety of the hull structure and securing of the ship's stability. As a result of verification of the safety of the hull structure, the value of the structural strength on both sides and the floor of the cargo hold for the total weight of cargo that can be loaded in the cargo hold was satisfied, and the value of the ship's stability was satisfied with the value of GoM and the restoration of the three cross-sectional stability curve areas.

• Journal of Korean Society of Forest Science
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• 제101권2호
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• pp.175-184
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• 2012

This study was conducted to develop new mattress systems with vegetation base materials for protecting stream bank and rapid rehabilitation. Vegetation base materials are primarily compounded with fine soil, organic composts and peat moss as plant fibers, a water retainer and a soil improver. Peat moss can usually provide necessary natural fibers and organic materials in soil. Especially, peat moss can absorb up to 25 times its own weight in water and is therefore valued as a water retainer to prevent drying effect of vegetation base materials which can harm the growth of vegetation in mattresses. Normally mattress systems resist the lateral earth pressures or stream power by their own weight. Therefore, filled materials must have suitable weight, compressive strength and durability to resist the loading, as well as the effects of water and weathering. In this project, 100 to 200-mm clean, hard stones were basically specified, and about 50-mm rubbles were also used. Test application of new mattress system carried out in the stream bank of a small stream in the Gwangreung experimental forest, belonging to Korea Forest Research Institute (KFRI) in December 16th, 2006. As a result of the monitoring of vegetation coverage of test application plots (each plot size is 4 by 2 m), the coverage of all plots reached 100% in the end of May, 2007 (approximately 50 days passed after the first gemination of vegetation). The coverage of the plots using big hard stones and organic composts and the plots containing peat moss increased more rapidly. The results show that peat moss is effective to retain soil moisture and establish more sound environment for vegetation gemination.

• Journal of Conservation Science
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• 제31권2호
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• pp.105-114
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• 2015

In this study, an advanced epoxy putty which was as a multi-purpose restoration material being used to restore missing parts in the artifact preservation treatment process was developed. For the purpose of addressing the issues including the workability issue resulting from high strength, the drooping issue resulting from long hardening time during work process and the issue of contaminating the surface of artifact resulting from stained material on tools or gloves, a property comparison was conducted with existing materials to examine the properties of restoration materials in the form of epoxy putty currently being frequently used. For the purpose of addressing the issues of existing materials and allowing the developed epoxy putty to have similar properties, two types of hardeners with different properties were selected to conduct property experiments. As for the hardeners, mercaptan type hardener and aliphatic amine type hardeners in the total of two types were selected for the development. The result showed that the two types were both in the form of paste and their hardening time of 5-10 minutes were about 3-10 times shorter than that of existing materials, thereby improving the work convenience. In terms of abrasion rate to increase workability, it was improved by about 3 times to allow effective and convenient use. As for the issue of contaminating the artifact surface during the process, white micro-balloon was added as filler to address the issue to reduce the oil ingredient to develop multi-purpose restoration material with low shrinkage & high workability in coloring, light weight and cutting force.