• 경영과정보연구
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• 제27권
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• pp.53-69
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• 2008

In this paper we analyse performance of value strategy and moving average method among the non-financial listed companies whose fiscal year ends at December in the Korean Stock Exchange between 1996 and 2005. And we analyse combination investment performance of value investment and moving average method. After the analysis objective enterprises divide with the value stock and the growth stock, in accordance with moving average method we divide ascending stock and descending stock. And we compose 6 portfolios with combination of value stock, growth stock, ascending stock and descending stock. Using the difference of investment performance of these portfolios, when fundamental analysis and technical analysis method all considering we measure investment performance. The major findings of this research are as follows: First, the value strategy of buying value stocks and selling growth stocks were effective in the long-term investment. Second, using the moving average method, technical analysis were effective in the case of the short-term investment. Third, the portfolios combined fundamental analysis and technical analysis were more effective than investment performance of technical analysis.

• 한국표면공학회지
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• 제38권6호
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• pp.216-226
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• 2005

Pb-Free Technology was born with environmental problems of electronic component, Being connected by big and small project of every country. Also, in each country environment is connected and various standards of IEC, ISO, MIL, JIS, KS, JEDEC, EIAJ etc. All products can divide at solder part and finishing part These can tested each and synthetically divide. This research is reliability evaluation for three kind of ph-free SnCu solder plating solution and it's deposit. First, executed analysis about Pure Sn, SnCu solutions and plating surface by way similar to other plating solution analysis. Next, executed reliability about test method and equipment for reliable analyzer system construction. Next, data comparison and estimation, main estimation test method and item's choice. In this paper the systematic surface analysis and reliability for plating solutions and it's deposit in metal surface finishing processes could be shown.

• 음성과학
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• 제5권1호
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• pp.89-103
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• 1999

It is relatively easy to develop a prototype of a Korean language processing system, but it is very difficult to make it an operational system. In this paper, we survey the current status and methodological issues of the Korean language processing systems such as morphological analyzer, parser and machine translator. In most cases, Korean language processing system easily comes to a dead-end state where its performance can not be improved any more. The reason is that it adopts a general algorithm covering similar problems as a whole because specific low-level problems are not clearly defined and their algorithms are unclear. So, when we add some restrictions to solve an individual linguistic problem, they are also applied to other linguistic phenomena as a side effect. It causes a critical problem that the improvement of the algorithm is very difficult. This paper proposes a 2-step paradigm, a divide-and-conquer method by the functional modularization, a simplification method, and an exception handling technique to develop an operational system that does not fall into a dead-end state.

• 정보교육학회논문지
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• 제12권4호
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• pp.477-484
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• 2008

본 연구는 남북한의 통일에 대비하여 남북간 극심한 격차를 보이고 있는 정보격차 해소방안을 구체화하기 위해 효율적인 통일전 격차해소 정책과 북한주민 정보화교육 방안을 구상하는데 기여하기 위한 것이다. 이를 위해 남북한 정보화 문헌연구와 정보조사, 타국 사례 등 선행연구를 바탕으로 통일분야와 IT분야 국가기관 및 단체, 기업의 전문가 및 실무자에 대한 설문조사를 바탕으로 델파이(Delphi) 실증기법을 통해 보다 현실성있고 구체적인 정보격차해소방안을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4502-4518
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• 2015

Fisher linear discriminant analysis (LDA) is one of the most popular projection techniques for feature extraction and has been widely applied in face recognition. However, it cannot be used when encountering the single sample per person problem (SSPP) because the intra-class variations cannot be evaluated. In this paper, we propose a novel method called local similarity based linear discriminant analysis (LS_LDA) to solve this problem. Motivated by the "divide-conquer" strategy, we first divide the face into local blocks, and classify each local block, and then integrate all the classification results to make final decision. To make LDA feasible for SSPP problem, we further divide each block into overlapped patches and assume that these patches are from the same class. To improve the robustness of LS_LDA to outliers, we further propose local similarity based median discriminant analysis (LS_MDA), which uses class median vector to estimate the class population mean in LDA modeling. Experimental results on three popular databases show that our methods not only generalize well SSPP problem but also have strong robustness to expression, illumination, occlusion and time variation.

• 대한의용생체공학회:의공학회지
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• 제45권3호
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• pp.118-127
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• 2024

Commonly deep learning methods for enhancing the quality of medical images use unpaired dataset due to the impracticality of acquiring paired dataset through commercial imaging system. In this paper, we propose a supervised learning method to enhance the quality of ultrasound images. The U-net model is designed by incorporating a divide-and-conquer approach that divides and processes an image into four parts to overcome data shortage and shorten the learning time. The proposed model is trained using paired dataset consisting of 828 pairs of low-quality and high-quality images with a resolution of 512x512 pixels obtained by varying the number of channels for the same subject. Out of a total of 828 pairs of images, 684 pairs are used as the training dataset, while the remaining 144 pairs served as the test dataset. In the test results, the average Mean Squared Error (MSE) was reduced from 87.6884 in the low-quality images to 45.5108 in the restored images. Additionally, the average Peak Signal-to-Noise Ratio (PSNR) was improved from 28.7550 to 31.8063, and the average Structural Similarity Index (SSIM) was increased from 0.4755 to 0.8511, demonstrating significant enhancements in image quality.

• 한국전자파학회논문지
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• 제17권8호
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• pp.732-738
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• 2006

10 GHz까지 동작하는 주파수 1/2 분배기와 주파수 1/4 분배기를 설계하였다. 회로에 사용된 설계 방법은 단일 위상 분주 방식이다. 단일 위상 분주 방식 분배기는 단 하나의 클럭 신호만을 필요로 하고 회로를 구성하는 소자도 크기가 작은 능동 소자로 이루어져 구조가 매우 간단한 장점이 있다. 측정을 통하여 바이어스 전압이 높아질수록 free running 주파수와 동작 주파수 영역이 높아짐을 확인할 수 있었다. 주파수 1/2 분배기와 주파수 1/4 분배기 회로에 바이어스 전압 $3.0{\sim}4.0V$, 입력 파워 16 dBm, 오프셋 전압 $1.5{\sim}2.0V$, 10 GHz 입력 신호를 가했을 때 입력 주파수의 1/2, 1/4에 해당하는 5 GHz, 2.5 GHz의 출력 신호를 각각 얻을 수 있었다. 주파수 1/2 분배기의 레 이 아웃 크기는 $500{\times}500 um^2$이고 측정용 패드와 연결 부분을 제외한 순수한 레이아웃 크기는 $50{\times}40 um^2$이다.

• Radiation Oncology Journal
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• 제5권2호
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• pp.165-168
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• 1987

The generalized Bathe method, proposed by Webb and Fox, which is a method of calculation of dose correction factor for the purpose of heterogeneous tissue, is complex even for a few kind of tissues. The method was modified for the purpose of getting a simple method that divide the multilayer of heterogeneous tissues into some groups of adjacent-tissue pairs. This new method could reduce the number of exponential terms and the time for calculating the dose correction factors by manual and computer calculation.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.551-556
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• 2009

3-D CAD (Computer Aided Design) system is an indispensable tool for manufacturing. A lot of engineers have studied for the methods to generate a curved surface on an N-sided shape, which is the basic technology of 3-D CAD systems. This surface generation, however, has three problems on the case of long and narrow shapes: the resultant surface is distorted, the surface is not continuous to adjacent surfaces, or additional user inputs are required to generate the surface. Conventional methods have not yet solved these problems at the same time. In this paper, we propose the method to generate internal curves that divide a long and narrow shape into regular N-sided sections so as to divide the shape into an N-sided section and four-sided ones. Our method controls the shape of internal curves by dividing an N-sided long and narrow shape into an N-sided section and four-sided ones, and solves distortion of the generated curved surface. In addition, each of the generated sections is interpolated with G1-continuous surfaces. This process does not require any user's further input. Therefore, the three problems mentioned above will be solved at the same time.

• 한국통신학회논문지
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• 제15권5호
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• pp.374-383
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• 1990

시각조사의 일은 대부분 숙련된 조사자에 의해 이루어지므로 시간이 경과 할수록 조사의 질은 감소한다. 그러므로 조사과정의 자동화가 요구되고 있으며, 실용적인 시각조사시스템을 위해서는 실시간에서의 데이터 처리능력, 다양한 입력물체에 대한 유연성 및 저렴한 시설비가 요구된다. 본 논문에서는 이러한 요구에 적합한 조사방법을 제안한다. 기존의 하드웨어 방식과는 달리 소프트웨어에 의해 조사데이터를 처리함으로써 조사시스템을 유연성 있게 하기 위하여 피라미드 데이터구조를 이용한 divide-and-conquer 기술과 간소화된 패턴 매칭방법을 결합한 시각조사 알고리즘을 제시한다. 이 방법에 의해 비교되는 패턴의 데이터 수를 감소시킬 수 있었고, 그 결과 조사속도를 줄일 수 있었다.