• 한국통신학회논문지
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• 제30권11A호
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• pp.1047-1055
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• 2005

무선랜은 특성상 단말의 이동이 빈번하게 발생하며, 핸드오프(Handoff)시마다 반복되는 인증으로 많은 오버헤드를 야기 시킨다. 따라서 본 논문에서는 안전하고 신속한 핸드오프를 위해 IEEE 802.11f의 IAPP(Inter Access Point Protocol)를 사용하며, 제안된 Context Block과 IEEE 802.11i의 4-way handshake만을 이용하여 핸드오프시에 RADIUS 서버와의 통신을 요구하지 않음으로써 효율성을 높였다. 또한 발생할 수 있는 Replay attack과 DoS 공격 등의 문제를 사전에 차단하기 위해 Context Block에 인증필드를 추가함으로써 보안상 취약점을 개선하였다.

• PNF and Movement
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• 제14권1호
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• pp.23-32
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• 2016

Purpose: The purpose of this study was to determine the effects of a coordinative locomotor training program on the functional movement screen (FMS) scores of badminton players. Methods: The participants consisted of 31 badminton players who were randomly assigned to either an experimental group (n=15) or a control group (n=16), and engaged in exercise five times per week for six weeks. The experimental group engaged in coordinative locomotor training and the control group engaged in general exercise. An FMS kit (USA) was used to measure the following: FMS score, deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push up, and rotary stability. Results: The FMS score, deep squat, hurdle step, in-line lunge, active straight leg raise, and trunk stability push up showed significant improvement in the experimental group (p<0.05). Conclusion: The coordinative locomotor training program was able to produce confirmation that functional movement screen scores change in the case of effective exercise interventions in badminton players.

• PNF and Movement
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• 제16권1호
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• pp.105-113
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• 2018

Purpose: The aim of this study was to explore the effects of dynamic balance training on pain, physical function, and dynamic balance in individuals with knee osteoarthritis. Methods: Fourteen patients with knee osteoarthritis participated in this study. The patients were randomly assigned to two groups: an experimental group (n=7) or a control group (n=7). All the patients took part in a lower extremity strength program for 30 min. In addition, the experimental group participated in a 30-min dynamic balance program. Both groups performed the program five times a week for 3 weeks. Outcomes, including the numeric rating scale (NRS), Western Ontario and MacMaster Universities Arthritis Index (WOMAC), and Community Balance and Mobility Scale (CB&M), were measured at baseline and after 3 weeks. Results: Both groups showed pre-to-post intervention improvements on all outcome measures (p<0.05). The experimental group showed a significant improvement in WOMAC (p = 0.00; Z = -2.82) and CB&M (p = 0.03; Z = -2.20) scores after the intervention as compared with those of the control group. Conclusion: The results revealed that dynamic balance training improved physical function, as well as balance ability, in patients with knee osteoarthritis as compared with that of a control group with no balance training.

• 한국표면공학회지
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• 제39권6호
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• pp.250-254
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• 2006

Effect of hydrogen partial pressure ratio on the structural and electrical properties of highly c-axis oriented ZnO films deposited by oxygen ion-assisted pulsed filtered vacuum arc at a room temperature was investigated. The hydrogen partial pressure ratio were $1.4%\sim9.8%$ at 40% oxygen pressure ratio. The conductivity of ZnO:H films was increased from 1.4% up to 4.2% due to relatively high carrier mobility caused by improvement of crystallinity While the conductivity of ZnO:H films were decreased over than 4.2% and (0002) orientation was also deteriorated. The lowest resistivity of ZnO:H films was $2.5{\times}10^{-3}\;{\Omega}{\cdot}cm$ at 4.2% of hydrogen pressure ratio. Transmittance of ZnO:H films in visible range was 85% which is lower than that of undoped ZnO films because of declined preferred orientation.

• 한국표면공학회지
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• 제49권6호
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• pp.490-497
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• 2016

In this study, 3-dimensional ripple structured anion (chlorine) doped ZnO thin film are developed, and used as electron transporting layer (ETL) in inverted organic photovoltaics (I-OPVs). Optical and electrical characteristics of ZnO:Cl ETL are investigated depending on the chlorine doping ratio and optimized for high efficient I-OPV. It is found that optimized chlorine doping on ZnO ETL enhances the ability of charge transport by modifying the band edge position and carrier mobility without decreasing the optical transmittance in the visible region, results in improvement of power conversion efficiency of I-OPV. The highest performance of 8.79 % is achieved for I-OPV with ZnO:Cl-x (x=0.5wt%), enhanced ~10% compared to that of ZnO:Cl-x (x=0wt%).

• 한국시뮬레이션학회논문지
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• 제12권3호
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• pp.55-68
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• 2003

As mobile IP has been suggested only to support mobility of mobile station(MS) by which it dose nothing but guarantee MS's new connection to the network, it is for nothing in Quality of Service(QoS) after handoff of MS. QoS is very important factor in mobile IP network to provide multimedia applications and real-time services in mobile environment, and it is closely related to handoff delay Therefore as a main issue in mobile IP research area, handoff delay problem is actively studied to guarantee and promote QoS. In this paper, in order to resolve such a problem, we suggest Simple Network Management Network(SNMP) information-based routing that adds keyword management method to information-based routing in active network, and then propose QoS controlled handoff by SNMP information-based routing. After setting up routing convergence time, modeling of suggested method and existing handoff method is followed in order to evaluate the simulations that are carried out with NS-2. The result of simulation show the improvement of handoff delay, and consequently it turns off the QoS has been improved considerably.

• 한국전문물리치료학회지
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• 제14권2호
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• pp.76-84
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• 2007

This study was designed to determine the efficacy of ultrasound and laser therapy for sub-acute lower back pain. Twenty-seven patients with sub-acute low back pain were recruited, who were randomly assigned to three groups: Ultrasound group (actual ultrasound, 1.1 MHz, $1.0W/cm^2$, duty cycle 100%, 10 min/session, n=9), laser group (actual laser, 904 nm, 155 ns, 13.5 W, 12 mW, 90 sec/point, n=9), and control group (placebo ultrasound or placebo laser, n=9). All of treatments including placebo procedures were applied to patients over a period of 2 weeks, five times a week. Visual Analogue Scale (VAS), Modified Schober's Test (MST), and Modified Oswestry Disability Questionnaire (MODQ) were used by the clinical and functional evaluations before and after intervention. At post-hoc, significant differences were observed in all groups with respect to VAS, MST (p<.05), except MODQ. VAS and MST score were more significantly improved in the ultrasound group than the laser and control group (p<.0167). However, no significant difference was present between the laser group and the control group. Therefore, this study revealed that ultrasound therapy was effective in pain relief and improvement of lumbar mobility in patients with sub-acute lower back pain. However, laser therapy did not show the effects for sub-acute lower back pain.

• 한국전자통신학회논문지
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• 제7권6호
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• pp.1487-1492
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• 2012

증가하는 이동단말의 인터넷 접속은 무선 IP망에서 노드의 망 이동 지원을 필요로 하게 되고, IPv6를 위해 모바일 IPv6를 제시되었다. 하지만 모바일 IPv6는 노드의 핸드오버로 인한 패킷손실을 발생시켜 망의 성능을 저하시킴으로 인해 이를 개선하기위한 다양한 방안들이 제시되고 있다. FMIPv6는 이들 방안들 중 하나로 끊어짐 없는 핸드오버가 가능하도록 설계되었으나 링크계층으로부터 정확한 핸드오버 시점을 결정해야하는 문제가 있다. 본 논문에서는 FMIPv6의 링크계층 의존성 문제를 해결하기 위해 가장 큰 지연시간을 갖는 이동노드의 CoA 등록과정을 사전에 수행하여 결정적인 부분의 지연시간을 최소로 줄이는 방안인 mptFMIPv6를 제안한다.

• 한국산업정보학회논문지
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• 제10권2호
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• pp.13-20
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• 2005

Ad Hoc 네트워크는 잦은 망 구성의 변화, 라우터의 수, 제한된 사용 자원 등 기존 유선 네트워크와는 다른 특성들을 가지게 된다. 따라서 기존의 유선 네트워크에서 사용하던 라우팅 프로토콜들을 Ad Hoc 네트워크에 그대로 적용시킨다면 많은 문제점들이 발생하게 된다. 본 논문에서 제안하는 라우팅 프로토콜은 Ad Hoc 네트워크의 특성을 고려하여, 네트워크 내의이동 호스트를 멀티 홉을 갖는 클러스터로 묶고, 클러스터 헤드로 하여금 자신의 멤버 호스트들과 이웃 클러스터들의 헤드 정보를 유지하게 하여, 경로 설정에 대한 요구가 있을 때에 적은 지연 시간과 적은 패킷으로 목적지까지의 최단 경로를 설정할 수 있도록 한다. 또한 경로 설정과 데이터 전송 모두가 클러스터 헤드를 이용한다. 이러한 경우 모든 데이터와 경로 설정 시 발생하는 패킷들이 클러스터 헤드로 집중되어 네트워크 부하가 발생하게 되는데 본 제안에서는 네트워크의 부하를 줄이기 위하여 후보 클러스터 헤드를 이용하는 방법을 제시한다.

• 한국전문물리치료학회지
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• 제20권4호
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• pp.40-46
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• 2013

The purpose of this study was to determine which spatiotemporal gait parameters obtained during hemiplegic walking could be a predictive factor for the Timed Up and Go test (TUG). Two hundreds nine subjects who had suffered a stroke were recruited for this study. They were participated in two assessments; the TUG test and gait analysis. The relationship between the TUG test and spatiotemporal parameters was analyzed using Pearson's correlation coefficients. In addition, to predict the spatiotemporal gait parameters that correlated most with the TUG scores, we used multiple linear regression analyses (stepwise method). The results show that the normalized velocity was strongly correlated with the TUG performance (r=-.72, p<.001). Additionally, single support percentage (SSP), double support percentage (DSP), step time difference (STD), and step length difference (SLD) significantly were correlated with the TUG test. Normalized velocity, STD, DSP of affected side, and SSP of non-affected side explained 53%, 8%, 3%, 2%, of variance in the TUG test respectively. In conclusion, an increase in gait velocity and a decrease in STD would be effective indicators of improvement on the functional mobility in the stroke rehabilitation.