• IEIE Transactions on Smart Processing and Computing
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• 제3권2호
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• pp.41-51
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• 2014

This paper describes a method to estimate the noise power using the minimum statistics approach, which was originally proposed for audio processing. The proposed minimum statistics-based method separates a noisy image into multiple frequency bands using the three-level discrete wavelet transform. By assuming that the output of the high-pass filter contains both signal detail and noise, the proposed algorithm extracts the region of pure noise from the high frequency band using an appropriate threshold. The region of pure noise, which is free from the signal detail part and the DC component, is well suited for minimum statistics condition, where the noise power can be extracted easily. The proposed algorithm reduces the computational load significantly through the use of a simple processing architecture without iteration with an estimation accuracy greater than 90% for strong noise at 0 to 40dB SNR of the input image. Furthermore, the well restored image can be obtained using the estimated noise power information in parametric image restoration algorithms, such as the classical parametric Wiener or ForWaRD image restoration filters. The experimental results show that the proposed algorithm can estimate the noise power accurately, and is particularly suitable for fast, low-cost image restoration or enhancement applications.

• 한국정보과학회논문지:소프트웨어및응용
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• 제33권10호
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• pp.862-867
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• 2006

영상을 처리하는 과정에서 광학시스템과 전자회로의 특성으로 인해 흐려지고, 잡음으로 훼손된 영상을 복원하는 경우에 일반적으로 정칙화 반복복원방법이 사용된다. 기존의 방법은 영상의 국부적인 특성을 고려하지 않고, 영상 전체에 일률적으로 정칙화 연산자를 사용함으로써 에지의 주변영역에서는 링잉현상을 초래하고, 평면영역에서도 잡음증폭을 피할 수 없으며, 또한 시각적으로 효율적이지 못한 면이 있다. 이러한 문제점을 개선하기 위하여 본 논문에서는 방향성 정칙화 연산자를 사용하여 평면영역과 에지영역의 특성을 고려하여 적응적으로 처리하는 반복복원방법을 제안한다. 실험결과, 제안된 방법은 기존의 방법에 비해 평면영역에서의 잡음 증폭을 억제하는 동시에 에지영역의 경계를 더욱 선명하게 복원함을 알 수 있었다.

• 한국환경복원기술학회지
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• 제16권2호
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• pp.23-40
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• 2013

The natural environment restoration industry has been newly included in the environment area of engineering technology. Accordingly, the enactment of a standard of estimate for determining the 'Cost plus Fixed Fee' method has become necessary for the implementation and vitalization of natural environment restoration projects. The purpose of this study is to determine the standards for which the prices for engineering projects are calculated with respect to the enactment of an engineering project standard of estimate in the natural environment restoration field. These include the scope of the technological work, standard area, manpower requirements by technical grade that are necessary for carrying out the technological tasks. Relevant laws and regulations, systems and precedent case studies were investigated and analyzed to establish a price calculation standard. The overall results of the analysis were used and applied to questionnaires, public hearings, and expert delphi techniques. The study showed the following results： The scope of the technological work was categorized into 'Biotopes', 'Eco-corridors' and 'Ecological restoration'. The standard area was set up as $1,000m^2$ for 'Biotopes' and $5,000m^2$ for 'Eco-corridors' and 'Ecological restoration'. The manpower requirements by technical grade that are necessary for carrying out the technological tasks were determined. The suitability of the costs, standard area, manpower requirements by technical grade of ordered engineering projects that are determined by applying the standard of estimate for natural environment restoration that may be enacted pursuant to this study may be effectively investigated and analyzed. Moreover, further studies on the calculation of standard prices that can ensure the stability of natural environment restoration projects will be necessary.

• 대한전자공학회논문지TC
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• 제41권5호
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• pp.53-61
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• 2004

본 논문에서는 GMPLS 네트워크의 생존성을 높이기 위해 서브네트워크를 이용한 2가지 유형의 동적 복구 방안들을 제안하고, 그의 특성을 분석한다. 제안한 방식은 전체 GMPLS 네트워크를 몇 개의 서브네트워크로 나누고, 장애가 발생된 장소에 따라 복구 방식과 보호 방식을 혼합하여 적용한 방식과 GMPLS 네트워크를 주 서브네트워크와 보조 서브네트워크로 나누고 장애가 발생한 지점에 따라 서브네트워크 별로 복구 방식을 적용하는 방안이다. 두 방식의 성능을 시뮬레이션을 통해 네트워크자원 이용 율과 복구 성공률, 평균 복구 시간을 분석하고, 기존 방식과 비교 분석하였다. 그 결과 기존 l＋l, 1:1, 1:N의 보호 방식보다는 두 방식 모두 자원이용 효율은 증가하였다. 복구 성공률과 평균 복구 시간은 기존의 경로 복구 방식에 비해, 단일 장애에 대해서는 우수하지만 다중 장애에 대해서는 약간 열세임을 확인하였다. 그러나 단일 경로에서 다중 링크 장애가 발생할 확률은 낮으므로, 실제 적용 시 문제가 되지 않는다.

• 한국환경복원기술학회지
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• 제21권6호
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• pp.83-93
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• 2018

In Germany has a long history of ecological restoration and restoration management. At the beginning of the 1990s, the "Erfolgskontrolle" was used as an evaluation program after the restoration project and many exchanges of views took place. It is the time, in Korea, there is a need for a comprehensive evaluation program after the restoration project, as there is no evaluation method yet. At this time it may be the "Erfolgskontrolle" in Germany as a practical model for the Korean restoration management program. The purpose of this study is to identify the concept and character of the "Erfolgskontrolle" and to demonstrate the implication and potential of application, through the analysis of the implementation example of the revaluation of river revitalization. To achieve the goal was carried out theoretical and 3 exemplary revitalization research cases. And it was endeavored to deliver the German way of acting and the basic idea to Korea. For the restoration, the "precautionary principle" should be considered first, the upper legal regulation should not be violated. In order to apply "Erfolgskontrolle" in practice, the goal formulation should be clear and systematically evaluated. And through the collection of typified cases, the comprehensive and unified theory should be established, it is possible, thus the qualitative assessment of the restoration project.

• 대한치과보철학회지
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• 제59권4호
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• pp.451-458
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• 2021

현재 치과치료의 다양한 분야에서 디지털 기술이 활용되고 있다. 특히 전치부 심미수복에 있어 기존의 전통적인 수복방식은 안모 정보를 담을 수 없고 환자가 치료 결과를 예상하기 어려운 반면 디지털 디자인을 통한 심미수복의 경우 보철물 디자인의 시각화 및 환자 피드백 반영의 용이성, 치료 결과에 대한 예지성을 얻기 쉽다. 본 증례는 전치부 외상 환자에게서 디지털 방식을 이용하여 예상되는 치료 결과를 환자가 치료 전 확인하고 피드백을 반영하여 진행하였다. 2D 디지털 스마일 디자인 방식은 환자의 안모 및 미소정보로 2차원 평면상에서 디자인이 이루어져 적용에 다소 제한되는 점이 있었으나 본 증례에서는 3차원 가상환자를 만들어 진행하였기에 디자인된 보철물에 대하여 다양한 각도에서 확인 및 수정이 가능하였다. 본 증례를 통하여 디지털 방식을 이용한 심미 수복시 환자 및 기공사와의 원활한 소통, 치료결과에 대한 높은 만족도를 얻어낼 수 있었다.

• 한국환경복원기술학회지
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• 제11권4호
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• pp.24-36
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• 2008

The essence of a natural stream restoration project is providing habitats for various creatures in terms of the stream's environmental function. This research suggests the problems of natural stream restoration project by studying streams in terms of habitats for creatures and reviewing the national and international cases on existing natural stream restoration project. As a solution for the above, this research suggests a preservation method for biotope of upper stream areas focusing on the fish biotope area considering the ecological characteristics and preservation value of the respective stream so that the stream can be preserved as habitats for creatures. The research was carried out on Cheonglimli Baekcheon region which is an upper stream area of Buan-Dam located in the public park in Byunsanbando, Buangoon, Jeonlabookdo. We suggest the preservation method based on the habitat environment and keystone species of fish. The habitat environment evaluation was carried out mainly being divided into three groups namely, habitats and surrounding environment, reservoir's features and fish way and the diversity of fish. By improving the problematic elements discovered through such evaluation, it tries to improve the biotope of the stream and continuously preserve the stream. In addition, in order to restore the stream as habitats for various creatures, this research suggests to select keystone species which are suitable for the stream environment and restore the habitats based on the keystone species rather than restoring habitats for all species. Fish not only plays the role of a consumer of Epilithic algae and water beetles but also plays an important ecological role as a food for birds or small mammalia. If such ecologically important biotope for fish is preserved, the ecological environment of the stream will be maintained more stably.

• 대한두개안면성형외과학회지
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• 제21권3호
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• pp.156-160
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• 2020

Background: We have reported orbital wall restoration surgery with primary orbital wall fragment in pure blowout fractures using a combination of transorbital and transnasal approach in pure blow out fractures. However, this method was thought to be difficult to use for complex orbital wall fractures, since the sharp screw tip that fixate the maxillary wall increases the risk of balloon ruptures. In this study, we reviewed 23 cases of complex orbital fractures that underwent orbital wall restoration surgery with primary orbital wall fragment and evaluated the result. Methods: A retrospective review was conducted of 23 patients with complex orbital fracture who underwent orbital restoration surgery with primary orbital wall fragments between 2012 and 2019. The patients underwent orbital wall restoration surgery with primary orbital wall fragment with temporary balloon support. The surgical results were evaluated by the Naugle scale and a comparison of preoperative and postoperative orbital volume ratio. Complex fracture type, type of screw used for fixation and complications such as balloon rupture were also investigated. Results: There were 23 patients with complex orbital fracture that used transnasal balloon technique for restoration. 17 cases had a successful outcome with no complications, three patients had postoperative balloon rupture, two patients had soft-tissue infection, and one patient had balloon malposition. Conclusion: The orbital wall restoration technique with temporary balloon support can produce favorable results when done correctly even in complex orbital wall fracture. Seventeen cases had favorable results, six cases had postoperative complications thus additional procedure seems necessary to complement this method.

• 한국통신학회논문지
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• 제37A권11호
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• pp.961-971
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• 2012

This article is concerned with effective numerical techniques for partial differential equation (PDE)-based image restoration. Numerical realizations of most PDE-based denoising models show a common drawback: loss of fine structures. In order to overcome the drawback, the article introduces a new time-stepping procedure, called the method of nonflat time evolution (MONTE), in which the timestep size is determined based on local image characteristics such as the curvature or the diffusion magnitude. The MONTE provides PDE-based restoration models with an effective mechanism for the equalization of the net diffusion over a wide range of image frequency components. It can be easily applied to diverse evolutionary PDE-based restoration models and their spatial and temporal discretizations. It has been numerically verified that the MONTE results in a significant reduction in numerical dissipation and preserves fine structures such as edges and textures satisfactorily, while it removes the noise with an improved efficiency. Various numerical results are shown to confirm the claim.

• 전자공학회논문지S
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• 제35S권12호
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• pp.77-83
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• 1998

일반적으로 동영상은 물체의 움직임에 의해 움직임 열화를 겪는다. 본 논문의 목적은 이러한 움직임 열화의 해석을 위한 모델을 제시하고 정칙화된 반복 기법을 이용하여 이를 제거하기위한 복원방식을 제안하는 것이다. 제안된 모델에서는 기존의 공간 불변적인 모델의 한계를 극복하기 위하여 움직이는 물체와 정지된 배경과의 경계에서 일어나는 현상을 수학적으로 해석하게 된다. 그리고 복원 과정에서의 객체기반적 처리를 위하여 움직임을 기반으로 하는 영상 분할 기법을 소개하는데, 이 기법은 기존의 연구를 바탕으로 본 연구에 맞도록 응용하여 사용한다. 제안된 모델을 근거로 한 영상복원 기법은 제약조건을 이용한 반복적 방법으로서 사전에 추정된 열화정보를 이용하여 움직임 열화를 제거하개 된다. 제안된 방법의 성능은 실험결과로서 확인할 수 있다.