• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.327-339
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• 2004

In this paper, we propose a new watermark algorithm for halftone images using iterative error minimizing method. In the proposed method, watermark bits are hidden at pseudo-random locations within a halftone image. To remove the distortions due to the inserted watermark bits and increase the invisibility of watermark, an iterative error minimizing technique is used. We define the halftoning error is defined as the difference between the original grayscale image and HVS-filtered printed halftone image. Then we iteratively find the pixel pattern with minimum halftoning error and displace the original pixel pattern with it. In order to be robust to geometrical modification like cropping or rotation, we insert the same watermark periodically into halftone images. Experiments using printed and scanned images show that the proposed method is a robust method to the geometrical modification and to hide the large amount of data within a halftone image without noticeable distortion.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2009.05a
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• pp.32-36
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• 2009

본 논문에서는 DCT영역에서 반복적 이진위상컴퓨터형성홀로그램을 이용한 디지털 영상 워터마킹 기술을 제안하였다. 워터마크로 주로 사용되는 랜덤 시퀸스 또는 로고와 같은 은닉영상 대신 은닉영상을 손실없이 재생할 수 있는 이진위상컴퓨터형성홀로그램을 생성하고, 이를 반복적으로 표현해서 워터마크로 사용한다. 그리고 이 워터마크를 호스트영상의 DCT 계수에 적절한 규칙을 통해 가중치를 부여하여 삽입한 후, IDCT한다. 워터마크의 추출은 워터마킹된 영상과 호스트영상을 DCT하고, 삽입시 적용한 규칙을 통해서 수행한다. 그리고 추출된 워터마크의 역푸리에 변환과 호스트영상에 삽입하기전의 워터마크를 역푸리에 변환하여 재생한 은닉영상과의 상관을 취함으로써 워터마크의 존재여부를 검증한다. 제안한 방법은 워터마크 삽입/추출시 반복되는 홀로그램정보를 활용하고, 이진 값으로 구성되어 있으므로 기존의 어떠한 워터마킹 기술보다 외부 공격에 견실한 특징을 가지고 있으며, 컴퓨터 시뮬레이션을 통해 그 성능을 확인하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.599-606
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• 2015

This paper proposes a Database Curriculum for Korean college students in the IT section. Most Korean college students in IT area should undertake Database subjects. However they are supposed to encounter identical troubles when studying the subjects. This may come from Korean culture. Therefore we analyzed out key issues that students must beware, and designed a curriculum accommodating the Korean culture.

• Cartoon and Animation Studies
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• s.5
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• pp.517-524
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• 2001

인간의 내면에 숨어있는 양면성을 주제로 그 양면의 극적인 대조를 이용하여 인간의 고뇌를 그리고, 타이포애니메이션을 이용하고 영상과 사운드의 접목을 통하여 인간내면의 갈등구조를 그리고자 했다. 겉으로는 일상적으로 반복되는 생활이 평화스럽게 보이지만, 인간의 내면에서는 항상 갈등이 존재함을 한 방울씩 떨어지는 반복적인 물방울 소리와 영상, 그리고 다듬이질 소리를 이용해 다들이질 치는 심장박동을 표현함으로써 대신하고자 했으며, 이와 더불어 극적인 타이포애니메이션을 구현하고자 했다. 인간내면의 갈등구조, 화면의 스크레치와 노이즈의 표현으로 이를 더욱 심화하고, 흑과 백, 그리고 맑은 영상과 비트있는 사운드를 통한 평화스러움과 인간내면 갈등구조에서 고뇌하면서도 평화스러워 보이는 한 인간의 속내를 표현하고자 했다. 인간내면의 갈등이 존재함에도 불구하고 평화스러워 보일 만큼 일상에 젖어 인간본연의 가치를 쉽게 잊고 살아갈 수도 있는 인간의 양면성, 급속한 변화를 담고 있는 현대사회 구조에 적응하여 살아가면서 느껴야 하는 무기력, 반복적인 생활, 획일화되는 사람들, 그러면서도 어쩔 수 없이 존재하는 내면의 갈등구조, 이 모든 것을 짧은 영상물에 담기에는 한계가 있으나, 어떤 결론을 만들어 제시하는 것이 아니라 상황의 표현에 중점을 두고 작품을 전개하려 했다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.1 no.1
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• pp.117-129
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• 1990

35 children(17 boys, 18 girls) with Recurrent Abdominal pain(RAP) without apparent organic causes, referrd from pediatric department of Seoul National University Children's Hospital were studied during 1988. 7. 1 ${\sim}$ 1989. 2. 28. The aims of this study are to examine clinical characteristics of the patients with RAP, to find possible factors influencing the onset and the course of the disorder, to evaluate the psychological status and the relationship with psychiatric diagnoses. The study subjects were compared with the age and sex matched control subjects on measures of social and school functioning, family-environment, behavior traits by CBCL and parent-environment rating scale. All patients and their mothers were interviewed by a child psychiatrist. The results were as follows ; 1) Abdominal pain was found to be more frequent when with a care taker, and related with traumatic life stresses such as separation from parents, death of family members. 2) Family members of the patients with RAP also had a high rate of a history of gastrointestinal dysfunctions with could not be attributed to organic etiologies. 3) Among 35 patients with RAP, 16 were diagnosed as psychiatric disorders. They were adjustment disorders (4), overanxious disorders (4), depression (2), tic disorders (2), attention deficit disorders (2), separation anxiety disorders (1), enuresis (1). 4) On CBCL, the patients with RAP were more internalized, socially less competent and less active compared with the control subjects. 5) According to the parent-environment rating scale, the patients with RAP had more conflicts with their parents about control issues. Family members of the patients with RAP were socially less competent and less abjustable. The parents of the patients with RAP were more affectionate and spent more time with their children but they were unfair and vague on instruction and discipline.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.627-638
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• 2012

This study empirically examines the concept of dynamic capability to recombine the resources such as directors, writers, and actors in the TV drama industry which is one of the most knowledge-based and project-based organizations. Based on the extant literature, it is argued that an organization's usage pattern of critical resources could partly reflect its dynamic capability. This study attempted to verify the hypothesis that Korean TV drama producers would utilize the same resources less repeatedly in the period with more uncertain environment(2003-2009) than the period with more stable and predictable environment(1994-2002). Empirical results partially support the hypothesis, verifying that there are different usage patterns in employing directors between the two periods but that is not the case in employing writers and actors. Such results imply that project-based organizations repeatedly use the same resources in order to pursue efficiency in stable environments whereas they tend to use a variety of different resources in order to adapt to uncertain environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.950-957
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• 2007

In this paper, a recursive intercarrier interference (ICI) cancellation technique for cooperative space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) with different carrier frequency offsets (CFOs) is proposed. Also, different CFOs existing in a cooperative STBC-OFDM system is shown to produce phase difference in the received signal, causing noise enhancement effect in the STBC decoding process. The performance degradation caused by the noise enhancement effect can be effectively reduced by a proposed ML-based recursive ICI cancellation technique. It is shown by computer simulation that the proposed recursive ICI cancellation technique is effective in reducing ICI, especially for STBC-OFDM systems with a large FFT size and large CFOs.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.447-456
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• 2005

This paper describes iterative restoration method of restoring blurred images using the LOG compansion function and Conjugate Gradient method. Conventional restoration methods results satisfy the requirement performance for restoring blurred images. but iteration number and convergence velocity increase. This paper proposed an opmtimised iteration restoration method for the images degraded by blurring effect, using the LOG compansion function and Conjugate Gradient method. Here, the LOG compansion function used to improve local properties of the image being restored, made the visual character and convergence velocity of the restored image improved. Throught the simulation results, the author showed that proposed algorithm produced superior performance results by conventional methods.

• 한국공간정보시스템학회:학술대회논문집
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• 2003.11a
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• pp.129-134
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• 2003

이동체란 시간 변화에 따라 연속적으로 위치가 변화하는 객체를 말한다. 이러한 이동체는 기존의 공간 데이터와는 달리 이동체의 위치변경 보고에 따라 지속적인 갱신연산을 발생시키는 특징을 가지고 있다. 이동체의 현재 색인에 있어 트리 기반의 색인 구조는 빈번한 갱신에 대한 색인의 변경 비용이 크므로 부적합하다. 확장 해쉬 기반의 그리드 파일 색인은 갱신연산의 비용이 적고, 그리드를 동적으로 구성하므로 공간 활용도가 높으며 영역 질의에 우수한 장점을 가지고 있다. 그러나 빈번한 갱신연산으로 인하여 해당 색인의 반복적인 분할/합병 비용을 발생시키는 문제점을 가지고 있다. 이 논문에서는 메인 메모리 기반의 그리드 파일을 구성하고, 빈번한 갱신연산에 따른 색인의 반복적인 분할/합병 비용을 제거하기 위한 합병정책을 제안한다. 특히 시간에 따라 해당 이동체의 수가 지역에 따라 변화하므로 이동체의 이동을 고려한 합병정책을 제안한다.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.109-109
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• 1993

Fourth branchial pouch anomaly is an extremely rare condition involving the pharyngeal apparatus with only about 30 cases having been reported in the last 20 years. It almost invariably occurs on the left side and typically presents with repeated episodes of neck swelling, recurrent thyroiditis, or repeated bouts of retropharyngeal abscess. This is a presentation of 2 patient with pyriform sinus fistula, presumably of fourth branchial origin, which, were successfully closed with 10ole trichloroacetic acid chemical cautery. Details of the cases along with the summary of embryology and fourth branchial anomaly are given.