• International Journal of Contents
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• v.9 no.2
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• pp.22-26
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• 2013

Comparing online and paper-based environment for report submission and correction, the former supersedes to the latter, since (1) the turn-around time becomes shorter, (2) teaching opportunity increases, and (3) as a consequence, the student's achievement level becomes higher in the online environment. In this paper, we propose an annotation tool GABA for PDF document in order to reduce correction time by the teachers and to facilitate instruction to students. In a usual class, the same or similar assignments are given to the students. Then it is often the case that many students make similar mistakes. A teacher can register and classify common correction comments to GABA. Report correction time becomes significantly shorter by reusing the registered comments. GABA also provides various support functions in order to assist efficient checking of numerous report files such as (1) sorting of frequently-used comments, (2) similarity-based file sorting, and (3) cross tabulation of comments using category and weight.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.945-957
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• 2012

Electronic documents have characteristics that detecting whether an electronic document is modified or not is not an easy process. Thus verifying integrity of documents is very important for using electronic documents. To facilitate this process, various electronic document software provide digital signature capabilities on themselves. However, there were not much research on the security of digital signature function of software. Therefore, in this paper, we analyze the security of Adobe PDF, MS Word, Hancom Hangul, digital notary service and digital year-end-settlement service, and propose recommendations for implementation of digital signature funcion.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.85-93
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• 2018

In recent years, there has been an increasing number of ways to distribute document-based malicious code using vulnerabilities in document files. Because document type malware is not an executable file itself, it is easy to bypass existing security programs, so research on a model to detect it is necessary. In this study, we extract main features from the document structure and the JavaScript contained in the stream object In addition, when JavaScript is inserted, keywords with high occurrence frequency in malicious code such as function name, reserved word and the readable string in the script are extracted. Then, we generate a machine learning model that can distinguish between normal and malicious. In order to make it difficult to bypass, we try to achieve good performance in a black box type algorithm. For an experiment, a large amount of documents compared to previous studies is analyzed. Experimental results show 98.9% detection rate from three different type algorithms. SVM, which is a black box type algorithm and makes obfuscation difficult, shows much higher performance than in previous studies.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.187-190
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• 2022

PDF (Portable Document Format)는 1992년 Adobe 에서 개발한 파일 형식으로 ISO 32000 으로 표준화 되어 전세계적으로 사용되고 있다. PDF와 같이 주로 사용되는 파일은 암호 해독(Password Cracking)의 대상이 될 수 있다. 본 논문에서는 PDF 1.4-1.6 암호 해독을 위해 CUDA GPU 상의 최적 구현하였다. 암호 해독에 사용되는 MD5와 RC4 알고리즘의 최적화와 CUDA GPU의 요소를 사용하였으며 RTX 3060 환경에서 크래킹 도구 해시캣과 비교하여 22.5%의 성능 향상을 달성하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.233-235
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• 2011

Because of various style-sheet and Korean-Fonts, converting from WYSIWYG types of HTML data to forms of PDF has many limitations. In print-work areas, for printing specific fonts, it has to use CMYK colors instead of RGB colors. This paper describes about the process to make web font to printing PDF files, which is high resolution image captured document based on HTML, by using COM component feature of hardware.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.71-82
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• 2024

With the advancement of information and communication technology (ICT), the use of electronic document types such as PDF, MS Office, and HWP files has increased. Such trend has led the cyber attackers increasingly try to spread malicious documents through e-mails and messengers. To counter such attacks, AI-based methodologies have been actively employed in order to detect malicious document files. The main challenge in detecting malicious HWP(Hangul Word Processor) files is the lack of quality dataset due to its usage is limited in Korea, compared to PDF and MS-Office files that are highly being utilized worldwide. To address this limitation, data augmentation have been proposed to diversify training data by transforming existing dataset, but as the usefulness of the augmented data is not evaluated, augmented data could end up harming model's performance. In this paper, we propose an effective semi-supervised learning technique in detecting malicious HWP document files, which improves overall AI model performance via quantifying the utility of augmented data and filtering out useless training data.

• Digital Contents
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• no.7 s.122
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• pp.48-53
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• 2003

PDF(Portable Document Format)와 XML(eXtensible Markup Language). 전자문서의 표준으로 서로 다른 방법론을 갖고 출발한 양 진영의 대결은 여전히 계속되고 있다. 최근 한국어도비시스템즈는 더욱 강력하고 새로운 기능들로 무장한 '애크로뱃(Acrobat)6.0'을 발표하면서 전자문서 시장에 대한 공세를 강화하고 있다. 이에 질세라 XML 진영에서는 ebXML, 로제타넷 등 XML 기반 응용솔루션에 대한 개발 및 영업에 더욱 박차를 가함으로써 부가가치 높이기에 적극적이다.

• Journal of Korean Library and Information Science Society
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• v.32 no.1
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• pp.285-307
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• 2001

With frequent use of the internet these days, academic libraries are offering the "Document Delivery Service" through the Internet in our country. The current "Document Delivery Service" utilized over the Internet was researched according to the method used by each library to connect to the internet. and this research, based on each library's current service conditions, service data types, document format of service data, whether the libraries used OPAC for document service or not, and user types. As a result of the research, it was discovered that most of the "Document Delivery Service" is served by website, mainly PDF format, use another interface differs from OPAC, and the personal users in our academic libraries.ers in our academic libraries.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.43-51
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• 2010

It is meaningful to investigate data in unallocated space because we can investigate the deleted data. Consecutively complete file recovery using the File Carving is possible in unallocated area, but noncontiguous or incomplete data recovery is impossible. Typically, the analysis of the data fragments are needed because they should contain large amounts of information. Microsoft Word, Excel, PowerPoint and PDF document file's text are stored using compression or specific document format. If the part of aforementioned document file was stored in unallocated data fragment, text extraction is possible using specific document format. In this paper, we suggest the method of extracting a particular document file text in unallocated data fragment.

• 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.