• The Journal of Korean Institute of Information Technology
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• v.16 no.12
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• pp.109-114
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• 2018

Collaborative filtering has been widely utilized in recommender systems as typical algorithm for outstanding performance. Since it depends on item rating history structurally, The more sparse rating matrix is, the lower its recommendation accuracy is, and sometimes it is totally useless. Variety of hybrid approaches have tried to combine collaborative filtering and content-based method for improving the sparsity issue in rating matrix. In this study, a new method is suggested for the same purpose, but with different perspective, it deals with no-match situation in person-person similarity evaluation. This method is called the transitive similarity model because it is based on relation graph of people, and it compares recommendation accuracy by applying to Movielens open dataset.

• Journal of KIISE:Software and Applications
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• v.35 no.12
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• pp.780-788
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• 2008

Modeling hand poses and tracking its movement are one of the challenging problems in computer vision. There are two typical approaches for the reconstruction of hand poses in 3D, depending on the number of cameras from which images are captured. One is to capture images from multiple cameras or a stereo camera. The other is to capture images from a single camera. The former approach is relatively limited, because of the environmental constraints for setting up multiple cameras. In this paper we propose a method of reconstructing 3D hand poses from a 2D input image sequence captured from a single camera by means of Belief Propagation in a graphical model and recognizing a finger clicking motion using a hidden Markov model. We define a graphical model with hidden nodes representing joints of a hand, and observable nodes with the features extracted from a 2D input image sequence. To track hand poses in 3D, we use a Belief Propagation algorithm, which provides a robust and unified framework for inference in a graphical model. From the estimated 3D hand pose we extract the information for each finger's motion, which is then fed into a hidden Markov model. To recognize natural finger actions, we consider the movements of all the fingers to recognize a single finger's action. We applied the proposed method to a virtual keypad system and the result showed a high recognition rate of 94.66% with 300 test data.

• Journal of the Korea Convergence Society
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• v.8 no.8
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• pp.51-57
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• 2017

A wireless sensor network is composed of many resource constrained sensor nodes. These networks are attacked by malicious attacks like DDoS and routing attacks. In this paper, we propose the intrusion detection and prevention system using convergence of software-defined networking and security technology in wireless sensor networks. Our proposed scheme detects various intrusions in a central server by accumulating log messages of OpenFlow switch through SDN controller and prevents the intrusions by configuring OpenFlow switch. In order to validate our proposed scheme, we show it can detect and prevent some malicious attacks in wireless sensor networks.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.153-163
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• 2019

This paper analyzes the film in a quantitative method to understand the principle to assign film's narrative as an art form. To do this, we tried to quantify 'conflict', which is a key factor of narrative, according to measuring the information represented in images. And thus, we measured the face areas of Protagonist and Antagonist, and then analyzed the relationship between area and conflict. The reason why the face area is used as the measurement target is because it is an index showing the way in which the director represents the conflict in the film. The quantification of conflict in films can be applied to indexing the narrative structure or specific conflict sections based on objective figures. In addition, it is possible to visualize narrative through conflict graphs, and it is meaningful that the computational criticism can apply into narrative study by quantification of conflict.

• The Journal of Korean Institute of Information Technology
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• v.17 no.7
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• pp.1-11
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• 2019

With the development of smartphones and wearable devices, researches related to platforms that collect lifelogs from these devices and the visualization of the lifelog results have also been advanced. However, the existed researches were impossible to collect data from various devices because they depended on a specific device and platform when transmitting or receiving lifelog data. In addition, they do not provide visualized analysis results of specialized lifelogs in specific areas, such as the users' location information. To resolve the problems, this paper analyzes user location information from the lifelog collection platform and develops the interface and visualization tools for lifelog collection. To do this, we define and analyze the requirements of developing the proposed system. Then, based on the analyzed requirements, this paper develops a lifelog visualization tool using various graphs, maps and the RESTful API interface and shows its implemented results.

• Journal of Software Assessment and Valuation
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• v.17 no.1
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• pp.51-58
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• 2021

Microservices are not only developed independently, but can also be run and deployed independently, ensuring more flexible scaling and efficient collaboration in a cloud computing environment. This impact has led to a surge in migrating to microservices-oriented application environments in recent years. In order to introduce microservices, the problem of identifying microservice units in a single application built with a single architecture must first be solved. In this paper, we propose an algorithm-based approach to identify microservices from legacy systems. A graph is generated using the meta-information of the legacy code, and a microservice candidate is extracted by applying a clustering algorithm. Modularization quality is evaluated using metrics for the extracted microservice candidates. In addition, in order to validate the proposed method, candidate services are derived using codes of open software that are widely used for benchmarking, and the level of modularity is evaluated using metrics. It can be identified as a smaller unit of microservice, and as a result, the module quality has improved.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.225-232
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• 2024

The Asynchronous indivisual learning offer advantages such as allowing learners to study at their preferred times without spatial constraints. However, since these classes are not conducted in real-time, there are limitations in conveying learners' feedback on problematic or inadequately explained course content to the instructors. This paper proposed a system for relaying feedback information from learners who view course content to the instructors. Learners can investigate the reasons for pausing online recorded class content, and they can transmit these pause reasons along with the time information of the paused content to the instructors. Instructors receive feedback information and pause times of learners' online recorded class videos in graphical form, making it easier to identify areas with numerous issues in the course content at a glance. Instructors can incorporate this feedback to re-upload the content, resulting in higher-quality course materials, which, in turn, can enhance learners' academic achievements.

• Journal of Digital Contents Society
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• v.11 no.2
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• pp.277-282
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• 2010

In this paper, the wireless transmission module is developed to transmit oxygen saturation(SpO2) signal, acquired from bio-signal measuring module, to PC. This wireless transmission module is designed with closed type protocol instead of open type protocol such as a zigbee or a bluetooth, considering of the security of personal medical informations. The display software is also developed to display transmitted SpO2 signals by various type data and graph without information loss for a emergency transfer.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.34-36
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• 2002

통합설계를 위한 대부분의 분할 알고리즘들은 분할과 스케줄링은 독립적으로 실행하므로 스케줄 결과에 따른 재분할의 잠재적인 오버헤드가 있다. 분할 단계에서 스케줄링을 함께 고려하는 FDS론 응용하는 방법은 분할할 노드를 선택하면서 동시에 그 노드가 스케줄 되어야 하는 제어구간을 함께 결정한다. 본 논문에서는 기존의 FDS 응용에 의한 분할 알고리즘[7]을 확장하는데, 목적 시스템으로서 하드웨어의 경우 여러 가지 구현 방법을 지원하고 소프트웨어의 경우 여러 개의 프로세서를 수용함으로써 다양한 하드웨어 구현 모듈과 프로세서에 의해 구성되는 내장형 시스템 설계에 적용될 수 있도록 하였다. 이를 위해 각각의 하드웨어 구현들과 여러 가지 프로세서들에서의 분포 그래프를 생성하고, 상대적 스케줄 긴박도를 구할 때 각 노드에 대해 해당 분할 영역에서의 실행 시간과 구현 비용을 고려하며 분할 영역간에 발생하는 통신 지연 시간을 힘 값에 반영하였다. 상대적 스케줄 긴박도를 이용한 분할은 스케줄과 분할이 동시에 이루어 져서 기존의 분할 알고리즘[9]보다 낮은 시간 복잡도를 보인다.

• 한국어정보학회:학술대회논문집
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• 2016.10a
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• pp.313-316
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• 2016

온톨로지란 사물이나 개념의 속성이나 관계를 사람과 컴퓨터 모두 이해할 수 있는 형태로 표현한 모델로 정보검색, 인공지능, 소프트웨어 공학 등의 분야에서 많이 활용된다. 온톨로지에는 다양한 정보가 구조화되어 저장되어 있지만 일반적으로 온톨로지가 제공하는 그래프 형태의 데이터들은 사용자들이 직관적으로 이해하기가 힘들다. 따라서 본 논문에서는 온톨로지의 정보를 문장화하여 한국어 문서를 생성하는 시스템을 제안한다. 제안하는 시스템은 주제와 관련된 트리플을 추출하고 이를 문장정렬, 결합, 생성을 위한 정보가 담긴 템플릿을 생성한 뒤 한국어 문법에 맞게 문장을 생성한다. 또한 기존 연구에서 다루지 않았던 이벤트 온톨로지의 내용을 포함하여 문장을 생성한다. 두 온톨로지로부터 생성된 문장을 연결하여 주제어를 설명하는 하나의 문서를 작성한다.