• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.93-99
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• 2018

The purpose of this study was to prove the effect of passive stretching after delayed muscular pain induction in university students and to propose a rehabilitation exercise program for effective pain relief and prevention in case of injury. Subjects were divided into passive stretching group and control group. Passive stretching group was performed passive stretching after delayed muscular pain induction and control group did not perform any treatment after delayed muscular pain induction. The delayed muscular pain induction method was induced by bench step motion. The height of the step box was 50cm. The data were analyzed by two-way RGRM ANOVA for comparison of passive stretching group and control group. In conclusion, passive stretching after delayed myalgia has a positive effect on blood fatigue (CRP, LDH) and subjective pain scale(VAS).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.3B
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• pp.179-187
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• 2002

This paper proposes and analyzes the iterative groupwise equal-delay interference cancellation(IGEIC) algorithm for coherent detection of an asynchronous wideband DS-CDMA system in a single cell over multipath fading channels. The IGEIC algorithm divide users in a system into several groups, and subtract out interference signal from the received signal as many as the number of users within a user group, iteratively. The IGEIC algorithm is also classified into the iterative groupwise equal-delay serial interference cancellation(IGESIC) algorithm and the iterative groupwise equal-delay parallel interference cancellation(IGEPIC) algorithm. In the case of perfect correlation for spreading codes, it shows that the performance of IGESIC and IGEPIC algorithm is the same after interference cancellation of as many as the number of users within a user group, but the performance of IGEPIC algorithm is superior to the IGESIC algorithm just before fecal cancellation within a user group. The results show that (he performance of the two proposed algorithms are also superior to the SIC algorithm by 3dB.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.179-184
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• 2003

One of the remarkable problems in PIM-DM (Protocol Independent Multicast - Dense Mode) is the join latency time, increasing for specific periods. The reason of this problem is proved to the confusion of flooding prune message and leave prune message. We propose a new solution to this problem, reducing the average join latency by 37.4%, and prove the proposed solution by network simulation.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.551-552
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• 2009

조선산업에서 선박의 건조 과정 중 탑재 공정은 작업자 간의 긴밀한 통신을 필요로 하며 매우 위험한 작업이다. 이러한 작업을 음성 품질이 매우 열악한 무전기나 호접속 지연이 많은 주파수 공용통신(TRS)를 이용하여 통신을 하고 있어 매우 위험하다. 따라서, 이러한 기존 통신방식을 대체하는 IP 기반 그룹통신 시스템과 이에 대한 품질 측정 및 평가가 필요하다. 본고에서는 IP 멀티미디어 시스템의 최초의 서비스인 PoC(PTT over Cellular) 서비스를 기반으로 조선산업에서 통합통신(Unified Communication)을 지향하기 위하여, 강재로 인한 매우 열악한 비가시 거리(NLOS)를 극복하고, 효율적인 통신 서비스를 제공하기 위한 엔터프라이즈 PoC을 기반으로 그룹통신의 품질을 측정하고 평가하였다. WiBro 기반 엔터프라이즈 PoC 서비스는 실제적으로 적용이 가능할 뿐 아니라, 실제의 작업자가 통신할때 지연이 느껴지지 않는 1초 이내의 그룹통신 지연시간에 대해 상기 서비스를 분석하였으며, 이론 상으로는 충분히 제공 가능함을 보이고 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.701-702
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• 2009

무선 센서 네트워크가 배포된 지역에 대하여 주기적으로 감시 값을 수집해야 하는 경우 라우팅 방법으로 계층적인 형태의 라우팅 방법을 주로 사용한다. 계층적인 형태의 라우팅 방법에는 특히, 클러스터를 구성하여 클러스터 리더가 클러스터에 속한 다른 노드들로부터 값을 모아 베이스 스테이션으로 전송하는 클러스터 기반 라우팅 방법이 일반적이다. 클러스터 기반 라우팅 방법의 경우 센서 노드간의 보안 서비스를 위해 그룹 키를 사용하는 경우가 있는데, 이 경우 그룹 키를 알고 있는 노드가 복수개 존재하기 때문에 그룹 키의 오용 가능성이 존재한다. 본 논문에서는 오용된 그룹 키를 탐지하기 위해 지연 응답 방법을 이용한 오용된 그룹 키 탐지 방법을 제안한다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.9
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• pp.652-662
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• 2001

A WDM/SCM multiple access protocol suitable for optical double star networks is proposed. A node-grouping scheme is employed in the protocol, which is accomplished by connecting some nodes through passive star sub-hubs forming a group. The resulting multiple groups in a network are then connected through a central passive star hub resulting in a passive double star network. Each group is pre-assigned a WDM channel as its home channel, and SCM channels are used to identify the packet reception at each node. [n the proposed protocol, the average packet delay is remarkably reduced since the frame consists of the number of groups rather than the number of network nodes. Furthermore, additional reduction of the average packet delay is achieved by limiting the propagation paths of control packets to the roundtrip between source nodes and sub-hub using a double star network. It is shown in the performance evaluations using analytic and simulation model that the proposed protocol has the advantages of the higher channel utilization and excellent network throughput and average packet delay characteristic.

• Restorative Dentistry and Endodontics
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• v.33 no.6
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• pp.526-536
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• 2008

The purpose of this study was to compare the effect of various dentin bonding systems on microtensile bond strength of immediate dentin sealing (IDS) and delayed dentin sealing (DDS). Eighteen extracted permanent molars were used in this study. The teeth for DDS group were restored with a provisional restorations, and immersed in saline solution for 1 week, and divided into 3 subgroups according to various dentin bonding adhesives; SB subgroup (3 step total-etch adhesive), SE subgroup (2 step self-etch adhesive), XE subgroup (1 step self-etch adhesive). In IDS group, the teeth were divided into 3 subgroups, and applied with bonding adhesives as in DDS group. The teeth were restored with provisional restorations, and immersed in saline solution for 1 week. Indirect composite disc was cemented with resin cement, and all specimens were subjected to microtensile bond strength. The data were statistically analyzed with oneway ANOVA and Student t-test. The results were as follows: 1. The IDS group showed significantly higher ${\mu}TBS$ than DDS group in 3 step total-etch and 2 step selfetch adhesive (p < 0.05). 2. In IDS and DDS group, 3 step total-etch adhesive showed the highest ${\mu}TBS$ value, followed by 2 step self-etch, and 1 step self-etch adhesive. In IDS group, the ${\mu}TBS$ value for 1 step self-etch adhesive was significantly different from those of the other subgroups (p < 0.05), and in DDS group, there were statistical differences in all subgroup (p < 0.05). 3. Failure modes of tested dentin bonding adhesives were mostly mixed failure and only 1 step self-etch adhesive showed adhesive failure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7C
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• pp.733-742
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• 2003

Unlikely unicast transmission, there are many elements that threaten security. Thus, key management of creating and distributing group keys to authorized group members is a critical aspect of secure multicast operations. To offer security in multicast environment, the recent researches are related to most group key distribution. In this thesis, we propose a group key management protocol for efficient, scalable, and multicast operation. This proposed protocol architecture can distribute traffic centralized to the key server. since the group key rekeyed by sub-group manager. The detailed simulation compared with other group key management protocol show that the proposed group key management protocol is better for join, leave, and data latency.

• Neonatal Medicine
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• v.18 no.1
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• pp.111-116
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• 2011

Purpose: To evaluate the impact of delayed interval delivery on neonatal outcomes. Methods: This was a retrospective study of infants who were born at Seoul National University Hospital by delayed interval delivery from June 2005 to July 2010. Outcomes (neonatal mortality and morbidity) of later babies were compared to those of the first babies and the control group whose gestational ages and birth weights were similar to them. Results: There were 4 twin and 5 triplet pregnancies. The first babies (group 1, n=9) were delivered at $22^{+6}$ to $27^{+5}$ weeks of gestational age, and the later babies (group 2, n=14) were born at $24^{+6}$ to $28^{+0}$ weeks. The mean interval between the first and later deliveries was 10 days, and there was no delay between the second and third deliveries in all triplet pregnancies. There were more small for gestational age (SGA) infants in group 1 than group 2 (66.7% and 21.4% respectively, P=0.03). Two of three babies who died in group 1 were born before 24 weeks of gestational age and expired within a week after birth. The mortality rate of group 2 (7.1%) was lower than group 1 (33.3%), but not significantly (P=0.106). The control group matched to group 2 consisted of 28 infants. There were no significant differences in neonatal mortality and morbidity between the two groups. Conclusion: Although there is a limitation to the number of infants in this study, it suggested that delayed delivery in a multiple pregnancy could decrease the incidence of SGA of the remaining fetuses and that prolonged gestation would not be harmful to those fetuses after birth.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.189-194
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• 2002

It is thesis that based on for Croup-Transferring a method of Transferring-Control during real-time. By the development of multimedia, spread of high-speed communication network and generalization of various multimedia services, various techniques an studied by requiring application services for multi-users (meeting-service, remote-service, broadcasting-service, education-service and so on). So we focused on the multimedia group transferring techniques except communication network techniques and multimedia processing techniques, and presented algorithms about a mettled of group-management, a method of delay-control-management that analyzed a effective method of Croup-Control and characters of each group network and used RTP(Real-Time Protocol) / RTCP(Real-Time Control Protocol).