• Journal of Information Technology Applications and Management
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• v.22 no.1
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• pp.17-36
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• 2015

Many companies are now trying to utilize SNS (social network service) by building it as marketing communication platform that delivers marketing messages and builds customer relationship. This study investigates the factors affecting consumers' intention to use of brand's SNS identity page (e.g., fan page in Facebook). It specifically focuses on four social support functions -self-esteem, informational, emotional and social networking support-in virtual space. Research model attempts to explore the impact of social supports on brands' SNS identity page adoption with modified technology acceptance model which includes perceived usefulness, ease of use and enjoyment. Empirical study adopts SEM (structural equation modelling) to test research model. The result indicates that perceived ease of use is influenced by informational support, and perceived usefulness is influenced by informational, emotional, and self-esteem support. And perceived enjoyment is influenced by emotional support. In addition, it reveals that there were no significant effects of social networking support on both perceived usefulness and enjoyment. These findings provide managerial implications for attracting potential and actual customers to brand's SNS identity page. And it also suggests the importance of managing sociability in brand's SNS identity page to make it as marketing communication platform.

• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.358-362
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• 2016

We present a new scheme for optical encryption of a binary image. In our method, the original binary data page is first divided into two identical pages. In each data page, the “on” and “off” pixels are represented by two discrete phases that are 90° apart. The first page corresponds to the phase conjugation of the second page, and vice versa. In addition, the wavefront of the two data pages is changed simultaneously from planar to spherical, for better encryption. The wavefront modification is represented by an extra phase shift, which is a function of position on the wavefront. In this way the two separate pages are both encrypted, and therefore the pages cannot be distinguished in a CCD. If the first page is used as an encrypted data page, then the second page is used as the decryption key, and vice versa. The decryption can be done by simply combining the two encrypted data pages. It is shown in our experiment that encryption and decryption can be fully accomplished in the optical domain.

• Journal of The Korean Association of Information Education
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• v.22 no.4
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• pp.409-417
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• 2018

There are unplugged computer science activities for elementary school students to learn the concept of the Internet. However, these activities are not enough to teach the concept of the Web because they focus on teaching how the Internet works. Since the Web is the core technology of the Third Industrial Revolution, it needs to be understood as a basic common sense. In this paper, we developed an unplugged activity to understand the PageRank algorithm which is closely related to the web. The experimental results show that our unplugged activities behave similarly to the PageRank algorithm.

• Journal of the Korea Society of Computer and Information
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• v.20 no.11
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• pp.31-38
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• 2015

Nowadays, large size flash memory drives with more than a couple of hundreds of gigabytes are common. This paper presents an efficient cache management scheme of flash translation layer, called TPC-FTL, for large size flash memory drives. Since flash drives of large size usually contain large size RAM, we can enhance the performance of page mapping cache by using more RAM for the cache. But if the size exceeds a threshold, the existing schemes are impractical for real devices, because the time for cache manipulation becomes too long. TPC-FTL manages the cache in translation page unit, not in logical page number unit used in existing schemes. Since a translation page covers a large number of logical page numbers (for example, 512 for 2KB size page), the number of cache elements can be reduced up to a practical level. A performance evaluation shows that average response time, an important performance measure, is better than existing schemes via the effect of utilizing spacial locality in addition to temporal locality.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.3
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• pp.172-183
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• 2010

Virtual memory systems (VM) reduce disk I/Os caused by page faults using page prefetching, which reads pages together with a desired page at a page fault in a single disk I/O. Operating systems including 4.4BSD attempt to prefetch as many pages as possible at a page fault regardless of page access patterns of applications. However, such an approach increases a disk access time taken to service a page fault when a high portion of the prefetched pages is not referenced. More seriously, the approach can cause the memory pollution, a problem that prefetched pages not to be accessed evict another pages that will be referenced soon. To solve these problems, we propose an adaptive page prefetching control scheme (APC), which periodically monitors access patterns of prefetched pages in a process unit. Such a pattern is represented as the ratio of referenced pages among prefetched ones before they are evicted from memory. Then APC uses the ratio to adjust the number of pages that 4.4BSD VM intends to prefetch at a page fault. Thus APC allows 4.4BSD VM to prefetch a proper number of pages to have a better effect on reducing disk I/Os, though page access patterns of an application vary in runtime. The experiment of our technique implemented in FreeBSD 6.2 shows that APC improves the execution times of SOR, SMM, and FFT benchmarks over 4.4BSD VM by up to 57%.

• Journal of Ginseng Research
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• v.13 no.2
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• pp.254-259
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• 1989

A radioprotective ginseng protein fraction was obtained from Korean white ginseng powder by the following isolation and purification procedures: Tris-HCI buffer extraction, 70% ammonium sulfate fractionation, CM-rellulosr column chromatography, heat inactivation and Sephadex G-75 column chromatography. This fraction was further purified by Sepharose 4B and Sephadex G-150 column chromatographies. Three fractions obtained were subjected to Native-PAGE and SDS-PAGE using gradient gels and the silver staining method. Molecular weights of the native proteins and their subunits were estimated.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.169-171
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• 2003

웹에서의 검색 방법에는 크게 Text-Based 기법과 Link-Based 기법이 있다. 본 논문은 그 중에서 Link-Based 기법의 하나인 PageRank 알고리즘에 대해 연구 하고자 한다. 이 PageRank 알고리즘은 각 페이지의 중요성을 수치로 계산하는 방법이다. 하지만 이 알고리즘에서는 페이지에서 페이지로 링크를 따라갈 확률의 값을 일정하게 주어서 모든 페이지의 값을 획일적으로 계산하였기 때문에 각 페이지의 검색 효율성에 문제가 있다고 판단하여, 이를 해결하고자 본 논문은 페이지사이의 유사도를 측정하여 유사도에 따라 링크를 따라가는 확률 값인 Damping factor값을 다르게 부여하여 검색의 효율성을 높였다. 이를 위하여 두 가지 방법의 실험을 통하여 구현, 증명하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.238-240
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• 2004

정보 통신 기술의 발달로 엄청난 양의 정보가 World Wide Web을 통해 저장되고 공유된다. 특히, 사용자가 WWW을 이용하여 필요한 정보를 얻고자할 때, 가장 많이 사용되는 것이 Web search engine이다. 그러나 Web search engine의 algorithm 자체의 부정확성과 악의적으로 작성된 Web page로 인해 search engine 결과가 사용자의 요구와 일치하지 못하는 문제가 발생한다. 본 논문에서는 여러 Web search algorithm 중에서 Web structure management 기법을 중심으로 문제점을 분석하고 이를 해결할 수 있는 수정된 algorithm을 제시한다. 마지막으로 제시된 algorithm이 spamming page를 filtering하는 과정을 예시하여 논증한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1602-1603
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• 2011

사용자의 접속 빈도를 분석하여 즐겨 찾기 사이트를 구성하는 크롬의 Front Page는 매우 유용한 기능이나 해당 브라우저에서만 사용할 수 있다는 제약이 있다. 이에 본 논문에서는 웹 브라우저에 대한 제약을 받지 않고 사용자의 취향에 맞는 웹 브라우저에서 Front Page를 구성할 수 있는 MyHome에 대해 기술하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.59-66
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• 2005

The organization of the web is progressively more being used to improve search and analysis of information on the web as a large collection of heterogeneous documents. Most people begin at a Web search engine to find information. but the user's pertinent search results are often greatly diluted by irrelevant data or sometimes appear on target but still mislead the user in an unwanted direction. One of the intentional, sometimes vicious manipulations of Web databases is a intentionally biased web page like Google bombing that is based on the PageRank algorithm. one of many Web structuring techniques. In this thesis, we regard the World Wide Web as a directed labeled graph that Web pages represent nodes and link edges. In the Present work, we define the label of an edge as having a link context and a similarity measure between link context and target page. With this similarity, we can modify the transition matrix of the PageRank algorithm. By suggesting a motivating example, it is explained how our proposed algorithm can filter the Web intentionally biased web Pages effective about $60\%% rather than the conventional PageRank.