계층적 다자간 회의에서 평균 경로 거리를 고려한 회의구성 알고리즘

성동수(Dongsu Seong) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.9

The multipoint conference in ubiquitous environment is expected to be one of the fundamental applications for various services, and ad-hoc hierarchical conference can be used well in this environment. When a new participant with a multimedia terminal wants to join an ad-hoc wireless hierarchical conference, our algorithm introduces a proper terminal in the conference and new participant's terminal sends a call request to the introduced terminal. The proposed algorithm selects adequate terminals in the conference to consider each terminal’s computing resources and introduces the terminal to minimize the average path distance between terminals among the selected terminals. The conference can be organized more efficiently in the environment to organize an ad-hoc hierarchical conference in comparison with the earlier scheme.

최단 거리 단말기의 소개를 이용하는 계층 회의 구성 방법

성동수(Dongsu Seong) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.8

The multipoint conference is expected to be one of the fundamental applications in ubiquitous environment, and hierarchical conference can be used well in this environment. The multipoint conference system using the endpoint mixing scheme causes the media data delay problem since the media data go through the hierarchical structure. In this paper, we propose an algorithm which minimizes the distance between terminals, and which considers the computing resource. When a new participant wants to join the ongoing hierarchical conference, our algorithm introduces a proper terminal in the conference and new participants terminal sends a call request to the introduced terminal which has the minimum distance from new participants terminal among the selected terminals with the computing resource consideration. As the experimental results with the proposed method, the hierarchical conference can be organized efficiently comparatively with the earlier schemes on the basis of media delay point of view because the average path distance between terminals can be reduced.

관광안내 시스템에서 GPS 위치 정보의 정확도 향상 알고리즘의 구현

김경태(Kyungtae Kim),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.5

In this paper, we introduce the position correction algorithm to reduce observation error in position determination technology using GPS, and the sight-seeing guidance system which uses this technology. Improved algorithm groups location coordinates collected during a period of time and minimizes error of the location coordinates by not using a large value of the error. Guide and tourists can acquire various sight-seeing information with the improved LBS algorithm. Voice communication between participants is possible by using multipoint communication. Through experimentation, Improved algorithm reduces more than the variance of the error when using only GPS value and reachs a value similar to the actual location coordinate. We find that the accuracy of location information is improved compared to previous sight-seeing systems, allowing tourists can acquire accurate sight-seeing information.

기계 학습을 이용한 특허 문서의 자동 IPC 분류

박찬정(Chanjeong Park),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.4

For the systematic classification, retrieval and efficient management of patent document, all patent documents are being given the IPC code. Classification experts at KIPI classify all patent documents for IPC classification by hand, currently in Korea. In this paper, we show the useful machine learning methods for automatic classification of IPC codes to each patent document. We conduct a performance evaluation of various feature selection algorithms and document classifier models. As learning and test data set, 8 kinds of patent documents extracted from IPC (sub)class are used. As the result, boolean weighting method, chi-square statistics and information gain are efficient for the feature selection, and the feature selection ratio of 20-40% is most efficient in the classification accuracy and computational cost. Also, SVM is slightly higher than the Naive Bayesian classification performance, but there were no significant differences.

계층적 통신을 이용한 유비쿼터스 관광안내 시스템의 구현

김도윤(Doyun Kim),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2010 한국정보기술학회논문지 Vol.8 No.2

In this paper, a ubiquitous sight-seeing guidance system is introduced. The system uses hierarchical communication and supports the individual sight-seeing and group sight-seeing. The voice communication between tourists to participate in the group sight-seeing is possible by using multipoint communication. The guide can get various sight-seeing information by using the representation terminal and RFID reader which he possesses generally, This information is delivered to all inside group's participants, and participants can hear an additional explanation from the guide to possess the representation terminal. Using such portable terminal, the tourist can take various sight-seeing guidance and pick up abundant sight-seeing information easily.

GPS 보정 및 스마트 단말기를 이용한 스마트 원격감시 시스템

김경태(Kyungtae Kim),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.11

In this paper, we introduce a smart remote surveillance system using the CCTV and the smart device. A server performs the PTZ(Pan, Tilt, Zoom) control of a CCTV and tracks the emergency requester using a CCTV in order to monitor the emergency situations in case of emergency. The GPS error correction algorithm is applied to reduce GPS error because reliability of emergency requesters coordinates is very important. With a GPS error correction algorithm, the variance of the error can be reduced in comparison with using only GPS value and we can take the appearance of an emergency requester using the smart remote surveillance system. In addition, the smart device can receive the CCTV image data and can do PTZ control.

회의 시간 감소율 최소화를 위한 무선 단말기의 최대 허용 이웃 단말기 수의 계산

김도윤(Doyun Kim),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2010 한국정보기술학회논문지 Vol.8 No.3

In a ubiquitous wireless environment, the operational meeting time of most mobile terminals is limited because a remaining power is limited. Especially, when such a wireless terminal is operated in a hierarchical conference, the case that all participant can not maintain the meeting during the determined meeting time may happen with a particular linking structure. In this paper, we propose the method to calculate the number of maximum allowable neighboring terminals of the terminal to minimize such meeting time reduction in a hierarchical conference of a wireless environment. When a hierarchical conference is constructed, the terminal to take a connection request determines the connection of new terminal after it compares number of the current neighboring terminal with the number of a maximum allowable neighboring terminals calculated with a consideration of a remaining power. If the proposed computational method is applied at the existing algorithms for a hierarchical conference construction, the meeting time reduction can be minimized.

위치기반 서비스를 이용하는 효율적인 단체관광 안내시스템의 구현

김도윤(Doyun Kim),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.1

In this paper, we introduce the efficient group sight-seeing guidance system which uses LBS and hierarchical communication. Guide and tourists to participate in the group sight-seeing can know the location each other, and can acquire various sight-seeing information with LBS service. The voice communication between participants in the group sight-seeing is possible by using multipoint communication. We know that a location information accuracy between tourists is improved in our system, and also know that average media delay between tourist's terminals is reduced through the experiment compared to previous group sight-seeing system.

사설망간의 VoIP 미디어 암호화를 위한 SBC내 RTP 처리부의 개선

박은성(Eunsung Park),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.8

VoIP in a ubiquitous environment is used mostly in the private network to have the effect of the firewall, and problems to be solved technically exist for this environment. For example, there is some problem in a media communication between the terminal in a private network and the terminal in a public network. Various existing methods can be used to solve these problems. Among these methods, the solution to use the SBC (Session Border Controller) server would be considered to be one of suitable methods. A ubiquitous environment has especially a weakness at the outflow of the secrecy from the tapping. A security technique for this is necessary and ZRTP can be used. There is no problem to encipher the information using ZRTP in the private network, but the problem happens in the data encryption using ZRTP between the terminal in private network and terminal outside the network through SBC. We modify the RTP processing unit in SBC which classifies and processes the general RTP packet and ZRTP/SRTP packet to prevent this problem. We know there is no problem in encrypted media communication between the terminals in different private networks as shown in the experimental results.

GPS 정확도 향상을 이용한 CCTV 보안 서비스의 구현

박은성(Eunsung Park),김기용(Kiyong Kim),성동수(Dongsu Seong),이건배(Keonbae Lee) 한국정보기술학회 2014 한국정보기술학회논문지 Vol.12 No.3

Smart care system can provide various security services using smart phones and CCTV cameras. The security services that can report dangerous situation and return home without fear should use the position informations obtained by GPS in smartphone of the user. In these services, the location information is used to track and record the user by using CCTV cameras which may have PTZ(Pan Tilt Zoom) capability. However, the position informations which are provided by GPS may have considerable accuracy errors up to several ten meters. For this reason, it is difficult to track and record the users location accurately. In this paper, we propose the method to correct position informations with GPS differential value, and the method to improve precision of security services with the corrected information, then we show the CCTV security service which is implemented with this method.