• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.05a
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• pp.67-75
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• 2004

인플루엔자 바이러스(Influenza Virus)는 Orthomyxoviridae 그룹에 속하는 RNA 바이러스로서 혈청형은 A, B, C 등 3형으로 구분된다. 그 중 B형과 C형은 사람에서만 감염이 확인되고 있으며, A형은 사람, 딸, 돼지, 기타 포유류 그리고 다양한 종류의 가금과 야생조류에서 감염이 확인되고 있다. (중략)

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.171-178
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• 2007

In mobile ad hoc networks, an application scenario requires mostly group mobility behavior in the mix of group moving nodes and individually moving nodes. The nodes of those applications tend to belong to the movement group with similar movement behavior. Group mobility is one of the good methods to improve scalability, and reduces the protocol overhead. In this paper, we propose the multicast architecture which regards nodes that have equal group mobility in the heterogeneous group mobility network as the single entity with the multiple interfaces and composes multicast tree, The logical cooperative entity-based multicast architecture accommodates the scalability, the multicast tree simplification, and the protocol overhead reduction which arc obtained from the hierarchical multicast architecture, while it maintains the nat multicast architecture for the data transmission. It also prevents the concentration of the energy consumption dispersing data forwarding load into the several ingress/egress nodes. Results obtained through simulations show that logical cooperative entity based multicast protocol with multiple interfaces offers the protocol scalability and the efficient data transmission.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.1
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• pp.37-48
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• 2004

Important Java network application services have been rapidly increased along with the growth of the Internet. So, it is desirable for such applications to serve transparently, continuously and safely even if the network is temporally partitioned or certain hosts running those services are crashed down. To satisfy such requirements, many group communication systems have been developed. However, existing Java-based group communication systems do not support both the extended virtual synchrony and various types of message delivery such as FIFO, causal, total and safe delivery service. In this paper, we present the design and implementation of a Java group communication system, named JACE, supporting various types of message delivery between group members and the extended virtual synchrony model. The JACE system consists of a number of protocol modules which can be stacked on top of each other in a variety of ways. In addition, using the JACE system, we have developed an experimental UDDI registry for discovering and publishing information about Web services.

• Korean Journal of Applied Biomechanics
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• v.14 no.2
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• pp.179-186
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• 2004

본 연구의 목적은 숙련된 골프선수들의 골프 스윙동작 시 상이한 무게중심 변환 형태가 존재하는지 그리고 만약 이 상이한 무게중심 변환 형태가 존재한다면 어떤 형태로 나타나는지를 알아보고자 하였다. 본 실험을 위해 13명의 남자 대학 엘리트 골프 선수들을 대상으로 드라이버를 이용한 스윙을 실시하게 하였다. 수직 지면 반력과 압력중심 이동 패턴을 측정하기 위해 지면반력기 2대와 스윙 동작 시 critical event 설정을 위해 1대의 고감도 비디오 카메라를 사용하였다. 또한 스윙 결과로 나타나는 비거리, 클럽헤드 속도를 측정하기 위해 스윙 분석기를 이용하였다. 피험자 간 상호 비교를 위해 측정된 수직 지면반력 성분은 몸무게를 이용하여 표준화하였고 압력중심은 어드레스시의 압력중심을 원점으로 재 계산하였다. 또한 임팩트 시 측정된 좌우 수직 지면반력 성분을 이용하여 두 가지의 상이한 스윙 스타일로 구분하였다. 연구결과 8명(62%)의 피험자에게서 좌측 수직력 성분이 상대적으로 높은 전족(FFS) 스타일임이 밝혀졌고 5명(38%)은 그 반대인 리버스(RFS) 스타일임이 밝혀졌다. 이 전족 스타일은 대부분의 골퍼들이 선호하고 또 그렇게 하여야만 한다고 믿고 있는 스윙방식이다. 이와 반대인 리버스 스타일은 코치들이 금기시 하는 스윙의 형태로서 초보자, 즉 비숙련 자에게만 나타나는 전형적인 스윙형태라고 인지되고 있다. 하지만 이 두 가지 스윙 스타일이 초보자가 아닌 숙련된 골프 선수들에게서도 실제 존재한다는 것이 본 실험 결과로 나타났다. 평균 압력중심 이동 패턴은 전후축 방향의 경우 RFS 스타일 그룹이 RFS 스타일 그룹에 비해 압력중심 이동이 크게 나타났고 좌우축의 경우에도 RFS 그룹이 FFS 그룹에 비해 압력중심 이동이 크게 나타났다. 특히 임팩트 시 압력중심의 위치가 FFS 그룹은 전족 근처에 있는 반면 RFS 그룹은 후족(rear foot)에 위치하여 두 스윙 스타일의 차이점을 분명하게 보여주었다. 따라서 비록 이 RFS 스타일이 대부분의 코칭 이론과는 상반되는 무게중심 이동 패턴을 보여주었지만 이 스윙 스타일이 잘못된 것이 아닌 실제 존재하는 하나의 스윙 스타일로 인식하여 스윙 지도 시 이에 알맞은 적절한 교습법을 마련해야 할 것이다.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.9
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• pp.1126-1134
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• 1999

최근 다양한 멀티미디어 서비스를 지원하기 위한 통신망 관리와 서비스 관리가 통합된 개방형 정보 통신망의 구조가 요구되고 있다. 이러한 구조를 기반으로, TINA-C(Tele-communications Information Networking Architecture-Consortium)에서는 분산 환경에서 분산 어플리케이션 객체들에 대한 복잡한 서비스 및 관리 인터페이스들을 간결하도록 객체그룹의 개념을 정의하고 있다. 이러한 환경 속에서 트레이딩 서비스는 통신 서비스를 제공하는 객체그룹간의 상호작용을 지원하는데 매우 중요하다.따라서, 본 논문에서는 객체그룹간의 상호접속을 지원할 수 있는 트레이딩 기능과 이들 트레이더들간의 연동을 위한 트레이더 연합 모델을 제시하고자 한다. 이를 위해 우리는 트레이더의 중개자로서 Cooperator를 설계하여 기존의 트레이더와 연동시켰다. 이러한 결과로서 우리의 새로운 트레이더 연합 모델에서 Cooperator는 객체그룹간의 상호접속에서 객체들의 접속 권한의 체크 기능과 기존의 트레이더 연합모델의 문제점인 트레이더들간의 단 방향 연결문제를 보완하여 양방향 연결 기능을 갖도록 하였다. 끝으로, 이러한 해결 과정을 보이기 위해 트레이더와 Cooperator들로 이루어진 본 연합모델에서 분산 객체그룹간의 상호접속 절차과정과 사건 추적 다이어그램을 보였다.Abstract Recently, the open networking architecture is required to support various multimedia services as integrated functions of network management and service management. Based on this architecture, TINA-C defines an object group concept for simplifying complex management and service interfaces, when distributed application is executed in distributed environments. Within the support environment the trading service is an important of the interacting object groups which provide a telecommunication service.Hence, we suggest the trader federation model for supporting interconnections between object groups and among existing traders by using the cooperator we designed, as an intermediator among traders. Our cooperator has functions for checking access rights of objects in object groups, and for providing bidirectional linkage among traders. Up to now, the existing trader federation models have a single directional linkage for interactions among traders. Finally, we showed the interface procedure and the event trace diagram of distributed object groups using our model consisted of traders and the cooperators.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6B
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• pp.921-929
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• 2010

Group communication that involves the setup of a list of users has been a topic of interest in mobile industry. Push to Talk over Cellular (PoC), a group communication service for cellular phone network, is a type of half duplex communications that allows a single person to reach an active talk group without making several calls, but a single button press. Based on this service, we build a new protocol called Push to Talk over Mobile Wimax that uses group communication service in 802.16e network. Also, weper formed simulation to verify and evaluate performance of the designed service in Mobile Wimax network. From the results of performance evaluation, network administrators can evaluate the stability of network and make a better of network's shortcoming and have decision to build the robust network.

• The Journal of Korean Association of Computer Education
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• v.9 no.2
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• pp.111-124
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• 2006

Multicast services are provided on the Internet in fast increasing. Therefore it is important to keep security for multicast communication. If a member of the group is removed, new group key has to be generated and distributed to all remaining members of group. Minimizing number of messages and operation cost for generation of the composite keys to be used to encrypting group key are important evaluating criteria of multicast key management scheme since generation and distribution of new keys for rekeying require expensive operation. Periodic batch rekeying can reduce these important parameters rather than rekeying sequentially in fashion one after another. In this paper, Hamming distance is calculated between every members to be removed. In batch rekeying the members with Hamming distance less than threshold are selected for rekeying procedure. With running the round assignment algorithm in the case of removing several members simultaneously, our scheme has advantages of reducing messages and operation cost for generation of the composite keys and eliminating possibility of collusion attack for rekeying. We evaluate performance of round assignment algorithm through simulation and show that our scheme is excellent after performance comparison of existent schemes and our scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1B
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• pp.1-7
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• 2008

In group location management, when a transportation system(TS) with multiple mobile subscribers(MSs) changes location area(LA), location management is performed by group location registration by TS, instead of individual location registrations by MSs. In previous works, although it is assumed that LA in group location management is the same as that in individual location management, it is not appropriate to assume the same sized LAs since MSs in a TS have different characteristics from MSs which are not in a TS from the aspect of the speed and aggregate call arrival rates. Thus, in this paper, we propose an efficient location management scheme based on individual and group location managements with different sized LAs, and the performance of the proposed scheme is analyzed from the aspect of signaling cost at the wireless interface. Results reveal that the proposed scheme outperforms the conventional scheme by selecting an appropriate sized LA for group location management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.139-149
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• 2007

Asynchronous OFCDM(Orthogonal Frequency and Code Division Multiplexing) systems must have a cell search process necessarily unlike synch개nous systems. this process is hewn initial synchronization and a three-step cell search algorithm is performed for the initial synchronization in the following three steps: OFCDM symbol timing, i.e., Fast Fourier Transform(FFT) window timing is estimated employing guard interval (GI) correlation in the first step, then the frame timing and CSSC(Cell Specific Scrambling Code) group is detected by taking the correlation of the CPICH(Common Pilot Channel) based on the property yielded by shifting the CSSC phase in the frequency domain. Finally, the CSSC phase within the group is identified in the third step. This paper proposes a modification group code with two or three block of the conventional CPICH based cell search algorithm in the second step which offers MS(Mobile Station) complexity reductions. however, the effect of the reduction complexity leads to degradation of the performance therefore, look for combination to have the most minimum degradation. the proposed block type group code with suitable combinations is the nearly sane performance as conventional group code and has a complexity reduction that is to be compared and verified through the computer simulation.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.93-102
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• 2009

Environmental monitoring applications measure temporature, humidity, and pollution degrees of large areas periodically and are essential for ubiquitous society. In this paper, we propose a sensor network MAC protocol that is applicable to environmental monitoring applications. The proposing MAC protocol has scalability by constructing multiple groups of sensor nodes as in SMAC protocol. Differently from SMAC protocol, however, ours have hierarchical structure between adjacent groups. Data transmission schedules are efficient since lower groups are synchronized to higher groups. Thus. the end-to-end delays and energy consumption can be reduced due to sequential transmission schedules. But since the nodes within the same group are synchronized to themselves. they have good adaptability and scalability compared to existing hierarchical approaches such as DMAC. We show by simulations that the proposing MAC protocol is superior to SMAC for environmental monitoring applications.