• 한국멀티미디어학회논문지
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• 제25권9호
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• pp.1273-1283
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• 2022

This paper presents a locally adaptive HDR algorithm using the integral image and MSRCR for LDR images with inadequate exposure. There are two categories in controlling the dynamic range, which are global and local tone mappings. Since the global ones are relatively simple but have some limitations at considering regional characteristics, the local ones are often utilized and MSRCR is a representative method. MSRCR gives moderate results, but it requires lots of computations for multi-scale surround Gaussian functions and produces the Halo effect around the edges. Therefore, in order to resolve these main problems, the proposed algorithm remarkably reduces the computation of the surrounds due to the use of the integral image. And a set of variable-sized windows is adopted to decrease the Halo effect, according to the type of pixel's region. In addition, an offset controlling function is presented, which is mainly affected to the subjective image quality and based on the global input and the desired output means. As the results, the proposed algorithm no more use Gaussian functions and can reduce the computation amount and the Halo effect.

• 대한핵의학회지
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• 제25권2호
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• pp.186-191
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• 1991

Radionuclide cardiac studies lend themselves exceptionally well to functional imaging. This is especially true for gated blood pool scan (GBP). Making functional images is also possible in radionuclide angiocardiography (RNAC). In this study we tried to validate the functional images obtained from RNAC by comparing it with GBP. Twenty three patients (16 patients with coronary artery diseases, 5 with hypertensive heart diseases, and 2 with nonspecific chest pains) underwent simultaneous RNAC and GBP at the same position (LAO $45^{\circ}$). From both studies, global ejection fraction, regional ejection fraction, phase image, amplitude image, stroke image, paradox image, maximum ejection and maximum filling rates were obtained. Global ejection fraction are almost same in both studies. Regional ejection fractions of apex and inferior portion of left ventricle calculated from RNAC are well correlated with those of GBP. Phase and paradox image, maximum ejection and maximum filling rates were obtained. Global ejection fraction are almost same in both studies. Regional ejection fractions of apex and inferior portion of left ventricle calculated from RNAC are well correlated with those of GBP. Phase and paradox images of RNAC are very similar to those of GBP. However, amplitude and stroke images are different. Regional ejection fractions of the left ventricular base, maximum ejection and maximum filling rates obtained from RNAC are significantly different from those of GBP. In conclusion, albeit all of functional images of RNAC is not same as GBP, regional walt motions and global left ventricular function are expected to be successfully analyzed by phase and paradox image and ejection fraction.

• Journal of applied mathematics & informatics
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• 제31권3_4호
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• pp.353-363
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• 2013

A variant of the global conjugate gradient method for solving general linear systems with multiple right-hand sides is proposed. This method is called as the global conjugate gradient linear least squares (Gl-CGLS) method since it is based on the conjugate gradient least squares method(CGLS). We present how this method can be implemented for the image deblurring problems with Neumann boundary conditions. Numerical experiments are tested on some blurred images for the purpose of comparing the computational efficiencies of Gl-CGLS with CGLS and Gl-LSQR. The results show that Gl-CGLS method is numerically more efficient than others for the ill-posed problems.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1998년도 Proceedings of International Workshop on Advanced Image Technology
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• pp.16.2-21
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• 1998

Old movies are often corrupted by randomly located blotches and scratches. In this paper were present an efficient method for detection and removal of these distortions. The presented method is composed of two separate steps: the detection process and the restoration process. In the detection process, blotch locations are detected through global motion segmentation, the sequential approach to motion segmentation, a robust model-fit criterion and so on, we form the algorithm for the algorithm for the global motion segmentation tuned to the blotch detection problem. In the restoration process, the missing data of the detected blotch areas are temporally extrapolated from the corresponding image areas at the preceding or the succeeding image frame with considering the global motion segmentation results. We apply the presented method to moving image sequences distorted by artificial blotches. The method works very well and provides a subjective improvement of picture quality.

• 대한원격탐사학회지
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• 제35권6_4호
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• pp.1363-1372
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• 2019

본 연구에서는 영상융합 기법을 적용하여 고해상 다분광 영상을 제작할 때 요구되는 융합 파라미터를 분석하고, 하나의 값으로 대표될 수 있는 융합 파라미터를 제시하고자 하였다. 이를 위하여, 한반도 영역을 촬영한 115장의 KOMPSAT-3A 영상을 대상으로 전정색 영상을 모사할 수 있는 선형회귀계수와, 융합영상 제작에 요구되는 융합계수를 분석하였으며, 대표 선형회귀계수와 대표 융합계수를 제시하였다. 대표 융합 파라미터를 사용하여 융합영상을 제작하였을 때, 각 융합영상 간 DN값의 차이가 최적의 융합 파라미터를 사용하였을 때보다 정량적으로 감소함을 확인하였다. 따라서 본 연구는 융합영상 제작에 반영되는 지역적 특성을 최소화할 수 있는 것으로, 융합영상을 하나의 제품 측면에서 제공할 때 활용 가치가 높다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제21권2호
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• pp.63-73
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• 2017

Segmenting the image into multiple regions is at the core of image processing. Many segmentation formulations of an images with multiple regions have been suggested over the years. We consider segmentation algorithm based on the multi-phase level set method in this work. Proposed method gives the best result upon other methods found in the references. Moreover it can segment images with intensity inhomogeneity and have multiple junction. We extend our method (GLIF) in [T. Dultuya, and M. Kang, Segmentation with shape prior using global and local image fitting energy, J.KSIAM Vol.18, No.3, 225-244, 2014.] using a multiphase level set formulation to segment images with multiple regions and junction. We test our method on different images and compare the method to other existing methods.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2019년도 제60차 하계학술대회논문집 27권2호
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• pp.401-402
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• 2019

The purpose of this study is to find specific service quality factors of enterprises that can maximize the perception of banks' services to users of commercial banks in China, and to establish empirically how these quality factors affect the bank's image. They also want to verify the impact of the positive image of the bank on the user's satisfaction and the willingness to use the bank's services. For empirical verification of this study, questionnaires will be used to customers who have used the services of each of the four commercial banks in China, and the survey was conducted. The collected data were analyzed using the SPSS using statistical techniques such as Cronbach' ${\alpha}$, Investigative Factor Analysis, Reliability Analysis, Correlation Analysis, Regression and Difference Verification. The results of the verification were summarized below. First, the quality of service of commercial banks has a partial positive effect on the bank's image. Second, the image of a commercial bank has a positive effect on customer satisfaction. Third, the image of a commercial bank has a positive effect on the purpose of use. Fourth, the image of commercial banks has a partial mediated effect between service quality and customer satisfaction. Fifth, the image of a commercial bank has a partial mediated effect between the quality of service and its intended use.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권9호
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• pp.889-897
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• 2010

현대의 대량화된 영상 관리 시스템은 영상의 특징을 표현하는 영상식별자에 대해 왜곡에 강인하며 빠른 검색 속도, 정확성 및 효율적인 저장 등의 기본 성능을 요구한다. 영상식별자 설계 방법은 기하학적 왜곡에 강인한 지역 방식과 빠른 검색 및 적은 저장 용량의 속성을 지닌 전역방식으로 구분 할 수 있다. 본 논문에서는 왜곡에 강하고 지역적 공간적 제약으로 인한 서로간의 차별성이 강화된 지역 기술자들로부터 각각 개개 차원의 특징 분포도를 분석하여, 두 영상간의 유사도를 빠르고 정확하게 측정할 수 있는 지역 기술자 및 전역 기술자의 속성을 가지고 있는 LFH(Local Feature's Histogram)기반 영상식별자를 제안한다. 또한 GPU를 사용하여 LFH를 구현하는 방법을 제시하며, 제안한 LFH와 대표적인 지역, 전역 방식인 SIFT 및 EHD 방식과 저장용량, 추출 시간, 검색 속도 및 정확률에 대한 성능을 비교하였다.

• 방송공학회논문지
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• 제5권1호
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• pp.31-40
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• 2000

본 논문에서는 MPEG-7의 여러 가지 서술자 중 영상의 에지 정보를 효과적으로 표현하기 위한 에지 히스토그램 서술자를 제안한다. 영상에서 추출된 에지 정보를 효율적으로 서술하기 위하여 영상 전체(global), 부분 영역(semi-global), 그리고 국부(local) 영역에 대한 에지 히스토그램으로 구분하여 에지 히스토그램 서술자의 구조를 채택하였다. 또한, 제안된 서술자의 에지 검출 기법은 기존의 픽셀단위 검출 방법과는 달리 블록단위 에지 검출을 사용함으로써 에지 특징의 추출 속도를 높이며 블록을 압축의 기본단위로 하는 MPEG-1, 2의 압축 비트스트림에서도 빠른 속도로 직접 에지 특징을 검출할 수 있는 장점이 있다. 제안된 방법이 MPEG-7의 비균질 질감 서술자로써 같은 부류에 속하는 웨이브릿 기반 서술자 및 국부 에지 기반 서술자와 비교하여 검색 효율과 특징 추출 속도가 모두 우수함을 실험을 통해 확인하였다.

• 무역학회지
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• 제46권6호
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• pp.55-71
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• 2021

The purpose of this study was to establish the causal structural model among brand image and country image associated with consumers' purchase decision of products. The specific objectives were 1) to analyze the effects of brand image on consumers' purchase decision of products, 2) to analyze the effects of country image on consumers' purchase decision of products, 3) to analyze the effects of brand image on country image, 4) to analyze the mediating effects of country image between brand image and consumers' purchase decision of products. The conclusions of this study are as follows: First, companies must have an advantage strategy for brand image along with country image. To this end, a strategy to promote the brand image through various media is effective. Second, it is necessary to find new transformation through the establishment of brand identity at the corporate level so that consumers can have a good impression on the brand image. Third, it is important for companies to make efforts at the level of brand image and country image to provide consumers with information that can increase expectations and actual satisfaction and to build product reputation. In addition, it is necessary to embody brand images and country images into global marketing mix strategies. Fourth, if companies build a brand image that symbolizes a differentiated culture, the brand image can have a positive effect on consumer purchase decisions. Along with this, companies can further increase their positive effects by developing representative brand image contents. Fifth, this study confirmed that the higher the image level of the manufacturing country in a situation where consumers' preferences are diversifying, the more the brand image leads to consumers' purchasing decisions. Therefore, brand managers are required to build a country image suitable for the existing brand image when advertising at the time of product introduction.