• 프린팅코리아
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• v.8 no.1
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• pp.126-129
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• 2009

이미 선진국에서는 보편성과 편리성에 따라 인쇄산업의 커뮤니케이션으로 자리 잡은 PDF. 그러나 우리나라는 아직 인쇄업체에서의 활용이 일반화되지 못할 실정이다. 때맞춰 여러 면에서 편리하고 트랜드로 자리잡을 인쇄산업에서의 PDF 활용 방안을 알기 쉽게 설명한 책이 나왔다. 동국대학교 지역연고진흥사업단이 인쇄혁명 'PDF 프린팅'이라는 책을 최근 발행했다. 애즈랜드 최현수 사장과 PDF 전문가 이능모씨가 공동 집필했다. 본지는 인쇄업체의 PDF 활용을 돕기 위해 본 책자의 주요 내용을 시리즈로 소개한다.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.4131-4136
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• 2016

Background: The population in northeast Thailand continues to present with hepatobiliary abnormalities, particularly periductal fibrosis (PDF) which is the result of chronic infection with liver fluke (Opisthorchis viverini; OV) and may lead to the development of cholangiocarcinoma (CCA). Although the prevalence of OV infection has been decreased due to a liver fluke control program over decades, the prevalence of PDF remains high. This study aimed to investigate demographic factors associated with PDF risk based on ultrasonography (US) screening. Materials and Methods: This cross-sectional study is part of the Cholangiocarcinoma Screening and Care Program (CASCAP), a prospective cohort study. Multiple logistic regression was used for data analysis. Results: In 55,246 subjects, the overall prevalence of PDF was 33.0% (95%CI: 32.6 - 33.4). Males (33.9 %) were at higher risk for developing PDF than females (32.2 %) (ORcrude = 0.93; 95%CI: 0.89 - 0.96; p-value < 0.001). Factors associated with an increased PDF risk, in addition to OV infection, included old age (${\geq}70$ years) (ORadj = 1.28, 95% CI: 1.14 - 1.44, p < 0.001) and hepatitis B infection (ORadj = 1.31, 95% CI: 1.11 - 1.55, p = 0.001). In contrast, number of praziquantel treatments (> 2 times) (ORadj = 0.54, 95% CI: 0.47 - 0.63, p < 0.001) and diabetes mellitus (ORadj = 0.57, 95% CI: 0.49 - 0.65, p < 0.001) were significantly associated with a decreased PDF risk. Conclusions: Future US screening should closely examine older people and hepatitis B subjects for the purpose of PDF surveillance among high risk groups for CCA. However, the results of inverse associations require further investigation in order to confirm our findings.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.3
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• pp.117-124
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• 2017

To access PDF documents on an electronic book, PDF documents need to be converted into EPUB which is a standard format of the electronic book. When converting a PDF document into EPUB format, we need to convert color representations from CMYK into RGB representation. It is possible to give a visual effect and a user interaction using a video and JavaScript supported by EPUB format. The schemes for converting from PDF to EPUB are studied in this paper. (1) The first study is to carry out not to lose the color conversion effect using an ICC profile. (2) The second one is a layout configuration in the conversion process. (3) The third one is to highlight a specific content such as quiz platform to provide interactive visual effect for electronic book readers. Finally, in this paper we will show the usability of EPUB based eBook converting scheme through user study.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.06a
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• pp.347-350
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• 2001

종래에 사용되어 왔던 1 차원 바코드가 정보를 포함하고 있는 데이터베이스에 접근하는 데이터 키 역할을 주로 해온 것에 비해, 2 차원 바코드는 다량의 데이터를 포함할 수 있고 고밀도의 데이터 표현이 가능하여, 호스트 컴퓨터의 데이터 베이스에 온라인 연결할 필요 없이 확인하고자 하는 사람이나 대상물에 대한 정보를 얻을 수 있다. 본 논문에서는 가장 널리 사용되는 2 차원 바코드 체계인 PDF417 을 중심으로, 디지털 카메라를 통하며 입력한 영상을 이진화하여 시작 심볼 또는 정지 심볼을 검색함으로써 2 차원 바코드 영역을 추출한 다음, 추출된 영역으로부터 바코드의 행과 열의 수, 오류수정 정도 등의 헤더정보를 검출하고 이를 바탕으로 코드정보를 추출하는 알고리즘을 제안한다.

• The Journal of the Acoustical Society of Korea
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• v.24 no.4
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• pp.224-229
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• 2005

In this paper, we Propose a novel cepstrum normalization method which normalizes the probability density function (pdf) of cepstrum for robust speech recognition in additive noise environments. While the conventional methods normalize the first- and/or second-order statistics such as the mean and/or variance of the cepstrum. the proposed method fully normalizes the statistics of cepstrum by making the pdfs of clean and noisy cepstrum identical to each other For the target Pdf, the generalized Gaussian distribution is selected to consider various densities. In recognition phase, we devise a table lookup method to save computational costs. From the speaker-independent isolated-word recognition experiments, we show that the Proposed method gives improved Performance compared with that of the conventional methods, especially in heavy noise environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6C
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• pp.857-864
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• 2004

Many image compression standards such as JPEG, MPEG or H.263 are based on the discrete cosine transform (DCT) and quantization method. Quantization error. is the major source of image quality degradation. The current dequantization method assumes the uniform distribution of the DCT coefficients. Therefore the dequantization value is the center of each quantization interval. However DCT coefficients are regarded to follow Laplacian probability density function (pdf). The center value of each interval is not optimal in reducing squared error. We use mean of the quantization interval assuming Laplacian pdf, and show the effect of correction on image quality. Also, we compare existing quantization error to corrected quantization error in closed form. The effect of PSNR improvements due to the compensation to the real image is in the range of 0.2 ∼0.4 ㏈. The maximum correction value is 1.66 ㏈.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.2
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• pp.69-76
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• 2023

Hundreds of thousands of passwords are lost or forgotten every year, making the necessary information unavailable to legitimate owners or authorized law enforcement personnel. In order to recover such a password, a tool for password cracking is required. Using GPUs instead of CPUs for password cracking can quickly process the large amount of computation required during the recovery process. This paper optimizes on GPUs using CUDA, with a focus on decryption of the currently most popular PDF 1.4-1.6 version. Techniques such as eliminating unnecessary operations of the MD5 algorithm, implementing 32-bit word integration of the RC4 algorithm, and using shared memory were used. In addition, autotune techniques were used to search for the number of blocks and threads that affect performance improvement. As a result, we showed throughput of 31,460 kp/s (kilo passwords per second) and 66,351 kp/s at block size 65,536, thread size 96 in RTX 3060, RTX 3090 environments, and improved throughput by 22.5% and 15.2%, respectively, compared to the cracking tool hashcat that achieves the highest throughput.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.06a
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• pp.341-345
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• 2001

물류 정보를 표현하는데 있어서 종래의 1 차원 바코드의 데이터 키가 가지는 기능만으로는 해결될 수 없는 상황이 발생함에 따라, 1980 년대 중반에 이르러 많은 데이터를 독립적으로 표현할 수 있는 2 차원 바코드가 등장하게 되어 그 사용이 점점 확산되어가고 있다. 본 논문에서는 가장 널리 사용되고 있는 PDF417 바코드 심볼로지가 어떻게 구성되는지 알아본다. 또한, 최대 1700 개의 데이터를 저장할 수 있는 이 심볼로지로 인코딩된 정보의 코드워드로부터 원래의 데이터를 디코딩하는 방법에 대하며 알아본다. 데이터를 효율적으로 인코딩하기 위해 정보가 숫자인지, ASCII 코드인지, 혹은 바이트 정보인지에 따라 다른 인코딩 방식을 사용하게 되는데, 그에 따른 디코딩 알고리즘을 제안한다.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.355-357
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• 2012

A probability density function (PDF) approach to account for turbulence-chemistry interaction in the context of large eddy simulation (LES) based simulation of scramjets is developed. To solve the high-dimensional joint-composition PDF transport equation robustly, the semi-discrete quadrature method of moments (SeQMOM) is recently proposed [1]. The SeQMOM approach addresses key numerical issues in LES related to the inaccuracies in computing filter-scale gradients, enabling an efficient and numerically consistent solution of the PDF transport equation. The computational tool is used to simulate a cavity-stabilized Mach 2.2 supersonic combustor.

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.301-311
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• 1994

The growth of amorphous and first crystalline phase, and phase sequence by solid state reaction were examined in Co/Si multilayer thin films by DSC and XRD. The experimental results were compared with the results expected by effective driving force models, PDF and effective heat of formation models.Amorphous phase growth was not observed in Co/Si system and it was consistent with the predicted result by effective driving force. It was observed that the first crystalline phase is CoSi. According to the PDF and effective heat of formation models, the first crystalline phases were CoSi and $CO_2Si$, respectively. The experiemental results were coincident with the PDF model considering structure factors. In case of the atomic concentration ratios of 2Co : 1Si and 1Co : 2Si, the phases sequences were $CoSi\to Co_2Si$ and $CoSi \to Co_2Si \to CoSi \to CoSi_2$, respectively and it was analysized through the effective heat of formation model. The formations of CoSi, $CO_2Si$ and $COSi_2$ in initial stage were controlled by nucleation and the activation energies for the nucleation of three phases were 1.71, 2.34 and 2.79eV.