• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1371-1372
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• 2012

협업 필터링은 유사한 사용자를 선별하여 아이템을 추천하는 대표적인 추천 방법이다. 협업 필터링을 이용한 추천에서 추천 품질은 유사 사용자를 선별하는 기법에 따라 크게 달라질 수 있다. 본 논문에서는 협업 필터링 추천의 품질을 크게 개선 시킬 수 있는 새로운 유사 사용자 선별 기법을 제안한다. 제안하는 기법에서는 Earth Mover's Distance (EMD)를 이용하여 사용자간의 유사도를 정의한다. EMD를 적용하기 위해서 각 사용자를 히스토그램으로 표현하며, 히스토그램 빈(bin)간의 거리를 정의한다. 이렇게 정의된 유사도를 이용하여 타깃 사용자와 유사한 사용자들을 선별하며, 이를 기반으로 타깃 사용자가 부여한 타깃 아이템에 대한 점수를 예측한다. 다양한 실험을 통하여, 제안된 기법이 기존 기법들과 비교하여 추천의 정확도를 최대 30%까지 향상시키는 것으로 나타났다.

• Journal of Korea Game Society
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• v.9 no.1
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• pp.127-134
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• 2009

This paper presents a motion generation technique for arbitrary morphologies with the user defined correspondences between joints. Users can define the controlling part in the source character and the part to be controlled in the target character in our system. To remove the restriction in the morphology of the target character, we use the pair of example posture sets. In our system, in order to provide the correspondence regardless of the number of joints, the deformed part in the target character is simplified into the direction vector. The final postures are then generated with the weighted sum of the examples. Our experimental results demonstrate that our approach can generate motions for various target characters and can control the user defined joints in real-time.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.3
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• pp.329-336
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• 2010

This study deals with the measurement of reflectivity as well as the distance accuracy with Terrestrial Laser Scanner(TLS) using time of flight methods and near infrared wave length, for a variety of user-made targets. Especially, point clouds' reflection to several targets was measured with Gretag Macbeth il spectrophotometer in the office. And the distance accuracy in comparison to reference distance for TLS performance evaluation, was tested after scanning the user-made targets and measuring the inter-pillars distances over the precise EDM calibration baseline. The results of test was shown that except white resin objects, with approx. 10m and 170m inter-pillar distances, other targets achieved the distance accuracy of several millimeters(mm) with respect to standard distances. Future work should be concentrate on a few parameters influencing on the distance accuracy such as atmospheric correction, instrument correction, the additive constant or zero/index correction, etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8908-8914
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• 2015

The Internet continues to grow and develop, but there are going to generate a variety of Internet attacks that exploit it. In the initial Internet environment, the attackers maliciously exploited Internet environments for ostentations and hobbies. but these days many malicious attempts purpose the financial gain so systematic and sophisticated attacks that are associated with various crimes are occurred. The structures, such as viruses and worms were present in the form of one source multi-target before. but recently, APT(Advanced Persistent Threat, intelligent continuous attacks) in the form of multi-source single target is dealing massive damage. The performance evaluation analyzed whether to generate audit data and detect integrity infringement, and false positives for normal traffic, process detecting and blocking functions, and Agent policy capabilities with respect to the application availability.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.61-69
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• 2019

In this paper, we propose a multisensory(i.e., visual-auditory-tactile) based AR system for the education of cultural heritage. The proposed system provides a multisensory interaction by designing a user to experience with a 3D printed artifact which is mapped by a virtual 3D content of digital heritage. Compared with the existing systems of cultural heritage education based on augmented reality(AR) technology, this system focused on not only providing learning experience via a sense of visual and auditory, but also a sense of tactile. Furthermore, since this systems mainly provided the direct interactions using a 3D printed model, it gives a higher degree of realism than existing system that use touch or click motions on a 2D display of mobile phones and tablets. According to a result of user testing, we concluded that the proposed system delivered the excellent presence and learning flow to users. Particularly, from the usability evaluation, a 3D printed target artifact which is similar in shape to original heritage artifact, achieved the highest scores among the various tested targets.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1055-1059
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• 2004

A RFID(Radio Frequency Identification) system is a kind of radio frequency communication system and a branch of automatic data collection system. RFID system consists of RFID tags(or transponders) and RFID readers(controllers). This paper deals with the wireless communication that acquires tag IDs through RFID readers, and show the implementation of the target system which transmits tag IDs and related information to the server on the Internet through the wireless local area network. Today's RFID systems are usually implemented with the wired communication environment. In this paper, however, RFID system is effectively realized with the widely deployed wireless local area network and various RFID data can be collected by the readers which are communicating with the wireless access points of the local area network. Through the Internet, users also can have easy access to the server on the web and retrieve, analyze, and utilize tags' information.

• Design Convergence Study
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• v.13 no.2
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• pp.143-164
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• 2014

In this study, we suggest a tablet-PC based application as an instrument for self-examination of dementia and aim to evaluate its usability for the practical use. The tool for the self-diagnosis of dementia is testing a person's sentence comprehension, which is investigated by the accuracy of a sentence-picture matching task, and the result of the test can differentiate individuals with dementia of Alzheimer's type from normal aging population. According to its use for diagnosis of dementia, we developed a new version of sentence-picture matching task by a cooperative study with NABLE(Neurogenic communication And Brain Lab at Ewha) and applied to the application as a main function. Targeting the New Silver who are preliminary aged people in Korea, this application can provide them with three values: 'self-', 'easy', and 'simple'. When using this application, users can gain these values by an instruction manual with the recorded guide voice, easy-to-use functions and the simplified menu structure of it. After prototyping, we conducted the usability test and it was proved as a result that the New Silver users can easily operate the application by themselves.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.934-940
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• 2014

Recently, the emergence of a variety of devices to be able to access web have brought many technological changes in the field of web development. However some web sites are still operating with a focus on computers, especially exclusive and slow developing job training related web sites which utilize a User Interface that targets only PCs. In this paper, we propose the job training management system which has a menu configuration and functions to be applied to a variety of devices, and also an applicable technologies for training students to access more easily. Finally, we evaluated its efficiency by applying the implemented system in the actual field.

• Review of KIISC
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• v.26 no.1
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• pp.92-98
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• 2016

IT기술이 발달함에 따라서 데이터는 대량화, 다양화 되었다. 그에 따라서 이를 침해하려는 다양한 공격기술들이 등장하고 있다. 특히, 지능형 타깃 지속 공격이라는 APT(Advanced Persistent Threat) 공격은 날로 발전하고 있다. APT공격 중에서도 특히 은닉형 악성코드를 이용한 공격들이 많이 등장하고 있다. 은닉형 악성코드는 사용자가 인식하지 못하도록 보안시스템을 우회하고, 중요 데이터의 수집 및 유출을 위하여 교묘하게 시스템에 숨어들어 악의적인 행위를 하는 형태의 악성코드를 말한다. 이러한 고도화된 악의적인 행위를 하는 악성코드를 탐지하고, 대응하기 위한 기술들은 아직까지 부족한 것이 현실이다. 본 논문에서 대표적인 은닉형 악성코드와 공격사례를 분석하여 이를 대응할 수 있는 방안을 고찰해본다. 또한 이를 통하여 고도화된 공격기술들에 대해 예방하고 대응하는 자료로 활용 가능하다.

• Review of KIISC
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• v.18 no.3
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• pp.101-108
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• 2008

어떤 조직이나 개인을 상대로 한 인터넷 자원에 대한 분산 서비스 거부 공격이 통상적인 위험이 되고 있다. 이런 공격은 봇넷이라는 수많은 감염되거나 침해된 좀비 머신을 통하여 이루어지고 있다. 우리나라에서는 홈네트워크의 구축으로 광대역 액세스를 가진 개인사용자의 호스트 컴퓨터가 주 공격대상이 될 수 있다. 특히 개인 사용자들은 인터넷 보안에 대한 낮은 인식과 제한된 방어 자원으로 인하여 공격자의 대표적인 타깃이 되고 있다. IRC(Internet Relay Chat) 네트워크를 이용하여 감염된 인터넷 호스트를 제어하고 관리하는 공격들이 증가하고 있어, 이에 대한 대책이 절실히 요구되고 있는 실정이다. 따라서 본 논문에서는 인터넷 호스트들을 감염시키고 원격에서 제어하는 악성 봇/봇넷의 기술 개요에 대하여 기술하고 분석하고자 한다. 또한 최근 증가하고 있는 P2P 봇넷에 대하여도 알아보고자 한다.