• 디지털콘텐츠학회 논문지
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• 제19권8호
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• pp.1545-1554
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• 2018

무선 단말의 이동성을 지원하기 위해서는 하나의 AP (Access Point) 처리 영역에 적어도 2개 이상의 AP를 중복배치하여 통신영역을 이어야 한다. 이러한 무선랜 환경에서 무선 네트워크의 효과적인 활용과 사용자에게 지원되는 서비스의 극대화 관점에서 끊김 없는 핸드오버는 매우 중요한 논점 중의 하나이다. 한편, 최근 급속도로 부상하고 있는 네트워크 가상화는 네트워크 관리의 유연성, 세밀한 제어, 편의성 등을 혁명적으로 제고하고 있다. 네트워크 가상화는 원래 유선랜 위주의 데이터센터 내에서 스위치들 간의 통신 홉을 줄이거나 우회하는 플로우 라우팅 테이블을 실시간 제어함으로써 사용자 지연시간을 단축시키고 네트워크 견고성을 높인다. 이 연구에서는 유선랜 위주의 네트워크 가상화 플랫폼 OpenFlow를 일반 AP를 사용하는 밀집된 무선 네트워크 환경에 적용하여 디지털 콘텐츠의 스트리밍 서비스를 위한 끊김 없는 핸드오버를 실현하고 평가한다.

• Clinics in Shoulder and Elbow
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• 제7권2호
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• pp.65-69
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• 2004

Purpose: The purpose of this study is to evaluate the short-term clinical outcome of the capsulolabral repair using absorbable suture anchor in traumatic anterior instability of shoulder. Materials and Methods: From June 2000 to September 2001, 15 shoulders with recurrent anterior instability were operated with arthroscopic Bankart repair using absorbable suture-anchor 'PANALOK' (Mitek, westwood, MA), and were followed up over 1 year (average; 13 months). The mean age was 23-years. There were fourteen males and one female. The mean duration from the initial symptoms to the operation was 24 months. Associated pathologies were Hill-Sachs defect in 12 cases, SLAP in 6 cases, and partial rotator cuff tear in 2 cases. The results were evaluated by patien's satisfaction, Modified Rowe Score in regard to joint stability, mobility, pain and function in comparison with the preoperative ones, and other complications. Results: At the last follow-up, the total Rowe Score increased from 38 points to 92 points. There were no recurrence and 14 patients among 15 patients gained pre-operative level of sports activity and no other complications. Conclusion: Effective capsulolabral repair could be obtained by the absorbable anchoring without any untoward complications. This procedure is simple and safe one and this system can be a good substitute for the metallic anchor.

• 대한한방내과학회지
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• 제41권1호
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• pp.88-96
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• 2020

Objectives: Osteonecrosis of the femoral head (ONFH) is caused by a circulatory disorder. If symptoms are not present, the patient's progress is observed, but if symptoms are present, non-surgical methods or total hip replacement are performed. Several case reports have described the effects of Korean Medicine treatment on ONFH, but the number of cases is still small, and few studies have used blood stasis-based herbal medicines like Hwaeo-jeon (HEJ). This study reports the effectiveness of Korean Medicine treatments, including HEJ, on a case of ONFH. Methods: A patient diagnosed with ONFH by CT and MRI was treated with Korean Medicine treatments consisting of herbal medicine including HEJ, bee venom pharmacopuncture, acupuncture, cupping, and physical therapy. The improvement of pain was assessed using a numerical rating scale. Inflammation levels were determined by blood tests conducted during hospitalization. Results: Korean Medicine treatment, including herbal medicine, resulted in good clinical improvement responses, including reduced pain, improved mobility, and reduced inflammatory levels in the blood tests. Conclusions: Korean Medicine treatments, including HEJ, may be effective for ONFH patients. Further studies are needed to determine the recovery of osteonecrosis and the improvement of post-operative aftereffects using Korean Medicine treatments, as well as the reduction of pre-operative pain.

• 한국소음진동공학회논문집
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• 제23권3호
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• pp.240-248
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• 2013

자동차 수동변속기 내 래틀과 같은 회전체 진동은 엔진 연소폭발 주기와 연동하여 발생한다. 이러한 충격형 진동 특성은 선형 시간 불변 분석법을 적용하여 살펴볼 수 있다. 기어의 동적 특성을 이해하기 위해, 특정 형태의 앞 바퀴 굴림 방식 수동 변속기에 대한 연구를 수행하였다. 첫째, 동특성 고유값과 주파수 응답함수를 기반으로 자유도를 줄이는 방법을 제시하였는데, 이는 행렬의 크기를 줄이는 효과적인 역할을 한다. 둘째, 단일 질량 플라이휠과 이중 질량 플라이휠의 동적 특성을 비교하였다. 모빌리티 분석을 기반으로 한 이중 질량 플라이휠의 효과를 검토하였는데, 이로부터 진동에 의해 가진되는 충격을 회피하기 위한 기본 개념을 이해 할 수 있다. 마지막으로, 두 단계 클러치 댐퍼로부터 유효 강성 값을 도출하여 선형 불변형 시스템 모델을 연구하였다. 두 단계의 서로 다른 클러치 강성조합을 이용하여 클러치 댐퍼의 동적특성에 대한 관계를 예측할 수 있다.

• 지역사회간호학회지
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• 제15권1호
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• pp.18-28
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• 2004

Purpose: The purpose of the study was to analyze the changes in functional status and caregiver burden after a community based case management program for stroke patients. Method: This study was designed as a one group pre and post test. A total of 61 stroke patients and their caregivers were sampled in three urban areas and two rural areas. Face to face interviews were conducted as a pre test one week before intervention, and a post test two weeks after intervention. The case management program consisted of four home visits and two telephone counseling sessions for assessment, education and providing information during the eight weeks. The collected data were analyzed with paired t test. Results: First, significant differences in functional status, and specifically mobility and cognition, were found between pre test and post test. Second, caregiver burden, in particular, objective burden was significantly decreased after 8 weeks. Third, the positive response for the services increased after 8 weeks. Conclusion: The community based case management program was effective to improve the functional status of stroke patients and to decrease the caregiver burden.

• 대한전자공학회논문지SD
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• 제46권10호
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• pp.1-8
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• 2009

본 논문에서는 아날로그 및 디지털 집적시스템에서 사용될 수 있는 온도변화에 무관한 파워-업 검출기 회로를 제안하였다. 제안된 파워-업 검출기는 트랜지스터의 문턱전압과 이동도의 상호 온도보상 기술을 이용하여 nMOS 분압기와 pMOS 분압기의 출력 전압이 온도에 무관한 특성을 갖도록 하여 온도 변화에 따른 파워-업 전압의 변화량을 최소화하였다. 68-nm CMOS 공정을 이용한 시뮬레이션 결과, 제안된 파워-업 검출기는 파워-업 전압 1.0V 기준으로 $-30^{\circ}C$에서 $90^{\circ}C$의 온도변화 조건에서 4 mV의 매우 작은 파워-업 감지 전압 변화량을 갖는 출력 특성을 보였고, 기존 회로에 비해 92.6%의 파워-업 감지 전압 변화량 감소를 확인하였다.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.24-28
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• 2012

In this study, we fabricated an amorphous InGaZnO pseudo-MOS transistor (a-IGZO ${\Psi}$-MOSFET) with a stacked $Si_3N_4/SiO_2$ (NO) gate dielectric and evaluated reliability of the devices with various thicknesses of a $SiO_2$ buffer layer. The roles of a $SiO_2$ buffer layer are improving the interface states and preventing degradation caused by the injection of photo-created holes because of a small valance band offset of amorphous IGZO and $Si_3N_4$. Meanwhile, excellent electrical properties were obtained for a device with 10-nm-thick $SiO_2$ buffer layer of a NO stacked dielectric. The threshold voltage shift of a device, however, was drastically increased because of its thin $SiO_2$ buffer layer which highlighted bias and light-induced hole trapping into the $Si_3N_4$ layer. As a results, the pseudo-MOS transistor with a 20-nm-thick $SiO_2$ buffer layer exhibited improved electrical characteristics and device reliability; field effective mobility(${\mu}_{FE}$) of 12.3 $cm^2/V{\cdot}s$, subthreshold slope (SS) of 148 mV/dec, trap density ($N_t$) of $4.52{\times}1011\;cm^{-2}$, negative bias illumination stress (NBIS) ${\Delta}V_{th}$ of 1.23 V, and negative bias temperature illumination stress (NBTIS) ${\Delta}V_{th}$ of 2.06 V.

• 대한기계학회논문집A
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• 제38권8호
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• pp.837-848
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• 2014

본 논문에서는 보행이 불편한 노인들의 효과적인 자가 재활을 위한 보행 보조 로봇의 개발에 대해 연구하였다. 개발된 로봇의 주요 특징은 크게 유아보행기 및 전동휠체어 메커니즘을 융합한 안전성 및 운동성향상과 가변저항 및 스테레오 카메라를 이용한 정확한 보행 추종 제어 알고리즘으로 나눌 수 있다. 구체적으로, 유아보행기의 메커니즘을 적용하여 사용자가 보행 중 넘어지는 사고로부터 안전을 확보하는 동시에 다리근육의 부담을 줄여줄 수 있는 골반지지대를 설계하였으며, 전동휠체어와 같이 구동모터를 이용하여 사용자가 적은 힘으로도 로봇을 이동시킬 수 있도록 하였다. 다음으로, 골반지지대에 부착된 가변저항을 이용하여 사용자의 보행 의도 및 방향을 로봇이 자동적으로 판단하고 사용자를 추종할 수 있도록 하였으며, 스테레오 카메라를 이용한 사용자 하체모션분석 알고리즘으로부터 추종 반응속도와 정확성을 한층 높였다. 최종적으로, 단계적인 보행 보조 실험을 통해 개발된 로봇의 사용자 보행 추종 성능을 실험적으로 검증하였다.

• 대한간호학회지
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• 제41권1호
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• pp.18-25
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• 2011

Purpose: This study was done to examine the effect of an integrated care service which included a combination of oriental and western care on health outcomes in elderly patients with degenerative arthritis. Methods: A prospective comparative design was used. Data were collected from May 1, 2008 to June 30, 2009 from 85 elderly patients with degenerative arthritis in the lower extremities who were followed in a hospital out-patient department for 8 weeks. The integrated care service group (n=36) received a combination of physical therapy, acupuncture, western medicines or herbal medicines, and the western care group (n=49) received physical therapy or western medicines. Functional independence, walking speed, rotation balance, pain intensity, service satisfaction and total medical costs for the two groups were compared at 8 weeks. Results: Functional independence (t=2.14, p=.036) and walking speed (t=2.51, p=.014) improved significantly in the integrated care group while pain intensity improved significantly in the western care group (t=3.35, p=.002). The integrated care group reported higher scores for service satisfaction (t=2.09, p=.041) and higher medical costs than the western care group (t=2.15, p=.035). Conclusion: The results suggest that integrated care services are effective modalities to improve mobility and quality of life for elders with degenerative arthritis.

• Journal of Communications and Networks
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• 제7권2호
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• pp.115-125
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• 2005

This paper discusses how to effectively design a next-generation wireless communication system that can possibly provide very high data-rate transmissions and versatile quality services. In order to accommodate the sophisticated user requirements and diversified user environments of the next-generation systems, it should be designed to take an efficient and flexible structure for multiple access and resource allocation. In addition, the design should be optimized for cost-effective usage of resources and for efficient operation in a multi-cell environment. As orthogonal frequency division multiple access (OFDMA) has turned out in recent researches to be one of the most promising multiple access techniques that can possibly meet all those requirements through efficient radio spectrum utilization, we take OFDMA as the basic framework in the next-generation wireless communications system design. So, in this paper, we focus on introducing an OFDMA-based downlink system design that employs the techniques of hybrid multiple access (HMA) and frequency group (FG) in conjunction with intra-frequency group averaging (IFGA). The HMA technique combines various multiple access schemes on the basis of OFDMA system, adopting the multiple access scheme that best fits to the given user condition in terms of mobility, service, and environment. The FG concept and IFGA technique help to reduce the feedback overhead of OFDMA system and the other-cell interference (OCI) problem by grouping the sub-carriers based on coherence band-widths and by harmonizing the channel condition and OCI of the grouped sub-carriers.