• 대한전자공학회논문지TC
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• 제47권12호
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• pp.45-51
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• 2010

모바일 클라우드 컴퓨팅의 핵심은 이동 노드가 끊임없는 서비스를 제공받는 것이다. Mobile IPv6(MIPv6)는 Internet Engineering Task Force (IETF)에 의해 표준화된 이동성 제공 프로토콜이다. Mobile IPv6 빠른 핸드오버 (FMIPv6)는 MIPv6의 확장으로, MIPv6의 단점들을 보완하기 위해 제안되었다. 최근 들어, 광대역 무선 제어 시스템 중 하나인 IEEE 802.16e 환경에서의 Mobile IPv6를 위한 빠른 핸드오버가 IETF에 의해 제안되었다. 이것은 교차계층 빠른 핸드오버를 제공하기 위해 설계되었다. 본 논문에서는 IEEE 802.16e 네트워크에서의 향상된 교차계층 Mobile IPv6 빠른 핸드오버를 제안한다. 제안하는 방식에서 새로운 접속 라우터는 2계층 트리거를 이용하여 이동 노드를 위한 새 주소를 생성한다. 이동 노드의 정보를 새로운 접속 라우터에게 알리기 위하여 새로운 베이스 스테이션에서 새로운 접속 라우터로 보내지는 2계층 메시지를 이용한다. 이동 노드의 새 주소를 획득하면 이전 접속 라우터는 이동 노드의 홈 에이전트에게 바인딩 갱신 메시지를 보낸다. 시그널링 비용과 핸드오버 지연에 대하여 제안하는 방안의 성능을 기존 방안들과 비교하여 성능평가를 수행한다. 결과를 통해, 제안하는 방안이 기존 방안들에 비해 IEEE 802.16e 네트워크에서의 빠른 핸드오버를 효과적으로 제공하는 것을 볼 수 있다.

• Journal of Nutrition and Health
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• 제42권5호
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• pp.442-452
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• 2009

흡연은 신체 내 산화 스트레스를 유발할 뿐 아니라 체내 항산화 상태를 악화시킨다. 따라서 흡연으로 인해 유도되는 산화 스트레스를 줄여주기 위한 여러 다양한 식품영양학적인 시도들이 되어져 왔다. 프로폴리스는 꿀벌이 자신의 생존과 번식을 유지하기 위하여 여러 식물에서 뽑아낸 수지에 꿀벌 자신의 침과 효소 등을 혼합하여 만든 천연 물질이다. 본 연구에서는 프로폴리스가 산화 스트레스로 인해 나타난 흡연자의 DNA 손상을 회복시키어 항산화 영양 상태를 개선시키는지를 보고자 하여 placebo를 사용하는 double- blind cross-over 인체시험을 수행하였다. 흡연자에게 800 mg의 프로폴리스와 placebo를 4주 섭취시킨 후 2주 washout period를 가진 뒤 다시 군을 바꾸어 교차시험으로 4주간 섭취시킨 후, comet assay에 의한 DNA 손상도 및 신체 내 항산화 효소 수준, 총 항산화력 및 항산화 비타민 상태를 분석하였다. 처음 2주 동안의 고갈기간 후에 흡연자 29명 (평균나이: 34.38 ${\pm}$ 1.73세)을 프로폴리스군과 위약군의 두 군으로 나누어 하루에 프로폴리스 또는 위약을 4주 동안 공급하였고 2주 동안의 washout 기간을 가진 후에 교차실험을 위해 대상자의 군을 바꾸어 다시 4주 동안 프로폴리스와 위약을 공급하였다. Comet assay로 분석한 대상자의 임파구 DNA 손상정도는 프로폴리스를 섭취한 군이나 위약을 섭취한 군 간에 차이를 보이지 않았으며 총 항산화 영양상태도 두 군 간에 차이가 나타나지 않았다. 적혈구 항산화 효소인 catalase, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) 활성도, 그리고 혈장 vitamin C와 tocopherol 수준도 프로폴리스군과 위약군 사이에 차이를 보이지 않았다. 따라서 흡연자에 있어서 프로폴리스의 항산화 효과를 평가하기 위해서는 앞으로 더 다양한 연구가 필요하리라고 생각된다.

• ETRI Journal
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• 제24권2호
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• pp.69-81
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• 2002

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP-centric signaling and control architecture based on the generalized multi-protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross-connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS-based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user-network interface and network-network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to generalized MPLS signaling.

• 대한간호학회지
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• 제34권4호
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• pp.609-616
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• 2004

Purpose. The prevalence of urinary incontinence (UI) among community-dwelling older women in Korea is not well known. This study examined the prevalence of UI and UI-related knowledge among community-dwelling Korean women aged 55 and over. Method. A cross-sectional descriptive-correlational study was conducted. Data were collected from 276 women aged 55 and over in a metropolitan city using a structured questionnaire. Result. Of 276 respondents, 28.3% (n=78) reported experiencing UI. More than 50% of respondents incorrectly agreed with the statement that UI is the result of normal aging, with only 20.9% realizing that there is an exercise that can control urine leaks when one coughs, sneezes, or laughs. Older women who had sought treatment had higher mean score for UI-related knowledge. Conclusion. This study revealed substantial misconception about UI among community dwelling older women, demonstrating that comprehensive educational programs need to be developed to increase knowledge of UI.

• Bulletin of the Korean Chemical Society
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• 제22권11호
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• pp.1192-1196
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• 2001

A diaphorase enzyme electrode for the catalytic reduction of NAD+ , the oxidized form of nicotinamide adenine dinucleotide, has been prepared. The enzyme layer grew spontaneously over an aminoethanethiol self assembled monolayer on a go ld plate electrode. The growth was accomplished by simply dipping the electrode covered by the aminoethanethiol monolayer into a solution containing both glutaraldehyde and diaphorase. We suggested that the glutaraldehyde as a cross-linking reagent was attached to the amino groups of the aminoethanethiol monolayer and the diaphorase enzyme molecules were bound to free aldehyde groups of the glutaraldehyde. Further attachments of the enzyme molecules over the bound enzyme molecules continued with the bridging of the glutaraldehyde. In frequency measurements with a quartz crystal microbalance, the frequency decrease was much more than it was for that of the enzyme monolayer formation, and an enzyme layer thicker than a monolayer was formed. The modified electrode was employed to reduce NAD+ , using diffusional methyl viologen as an electron transfer mediator. The NAD+ was electrocatalytically reduced, and the catalytic current was almost equivalent to that with the multilayered electrode of ten enzyme layers.

• Structural Engineering and Mechanics
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• 제88권3호
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• pp.287-299
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• 2023

This article describes experimental and numerical analyses of eccentrically loaded over the axially loaded circular concrete filled double-skinned steel tubular (CFDST) short columns. Tests on circular CFDST short columns under eccentric and concentric loading were conducted to assess their responses to the frequent intensity of 5-30 mm at the interval of each 5 mm eccentric loading conditions with constant cross-sectional proportions and width-to-thickness ratios of the outside and internal tubes. The non-linear finite-element analysis of circular CFDST short columns of eccentrically loaded over the axially loaded was performed using the ABAQUS to predict the structural behavior and compare the concentric loading capacity over the various eccentric loading conditions. The comparison outcomes show that the axial compressive strength of the circular CDFST short columns was 2.38-32.86%, lesser than the concentrically loaded short column with the inner circular section. Also, the influence of computer simulation employed is more efficient in forecasting the experimentally examined performance of circular CFDST stub columns.

• 원예과학기술지
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• 제33권3호
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• pp.396-402
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• 2015

This study identified a new male-sterile germplasm of Chinese jujube, named male-sterile No. 2 (JMS2), and achieved controlled hybridization using that germplasm as the female parent. The anthers of JMS2 before flower bud opening became shrunken, dingy yellow and much smaller than normal ones, and they changed to brown after anthesis. No pollen was observed in anthers of JMS2 and its male-sterile trait remained stable over different years. A total of 1,642 fruits were obtained from ten intra- and interspecific cross combinations via controlled hybridization from 2008 to 2012 using JMS2 as the female parent. Of those, 27.3% produced seeds, on average (0-72.6%). The rate of fruit with seed (RFS) was significantly different between cross combinations or years. Compared to other cross combinations, the RFS in the combination of JMS2 ${\times}$ 'Xingguang' (a Chinese jujube cultivar with high resistance to jujube witches' broom disease) and JMS2 ${\times}$ 'Xing16' (a sour jujube genotype) remained high in different years and reached means of 48.7 and 58.1%, respectively. Finally, 150 plantlets were regenerated from immature embryos, and 51 of them were randomly selected and identified to be authentic hybrids using amplified fragment length polymorphism (AFLP) markers. This is the first report of hybrids obtained from a cross between Chinese jujube and sour jujube.

• Steel and Composite Structures
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• 제19권6호
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• pp.1561-1580
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• 2015

No significant improvement has been observed on the seismic performance of the ordinary steel reinforced concrete (SRC) columns compared with the reinforced concrete (RC) columns mainly because I, H or core cross-shaped steel cannot provide sufficient confinement for core concrete. Two improved SRC columns by constructing with new-type section steel were put forward on this background: a cross-shaped steel whose flanges are in contact with concrete cover by extending the geometry of webs, and a rotated cross-shaped steel whose webs coincide with diagonal line of the column's section. The advantages of new-type SRC columns have been proved theoretically and experimentally, while construction measures and seismic behavior remain unclear when the new-type columns are joined onto SRC beams. Seismic behavior of SRC joints with new-type section steel were experimentally investigated by testing 5 specimens subjected to low reversed cyclic loading, mainly including the failure patterns, hysteretic loops, skeleton curves, energy dissipation capacity, strength and stiffness degradation and ductility. Effects of steel shape, load angel and construction measures on seismic behavior of joints were also analyzed. The test results indicate that the new-type joints display shear failure pattern under seismic loading, and steel and concrete of core region could bear larger load and tend to be stable although the specimens are close to failure. The hysteretic curves of new-type joints are plumper whose equivalent viscous damping coefficients and ductility factors are over 0.38 and 3.2 respectively, and this illustrates the energy dissipation capacity and deformation ability of new-type SRC joints are better than that of ordinary ones with shear failure. Bearing capacity and ductility of new-type joints are superior when the diagonal cross-shaped steel is contained and beams are orthogonal to columns, and the two construction measures proposed have little effect on the seismic behavior of joints.

• 한국통신학회논문지
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• 제41권1호
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• pp.58-65
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• 2016

위성 통신은 넓은 지역에 통신 서비스를 제공하는 광역 네트워크이다. 하지만, 위성 통신은 대역폭이 제한되고 매우 긴 전파 지연 시간과 높은 BER(Bit Error Rate)로 인해 위성 통신을 고려하지 않은 TCP의 성능이 저하 된다. 본 논문에서는 위성 통신에서의 TCP 성능을 향상시키기 위해 DVB-RCS(Digital Video Broadcasting-Return Channel via Satellite) 네트워크 환경을 고려한 cross-layer 기반 PEP(Performance Enhancing Proxy) 기술을 제안한다. 제안하는 프로토콜은 TCP와 링크 계층 간 위성 자원 할당 정보를 정보 교환을 통해 최적의 TCP CWND(Congestion Window)를 설정한다. 제안한 프로토콜의 성능 평가를 위해 리눅스 기반의 PEP 테스트 베드를 구현하였다. 성능 평가 결과 다양한 BER에서 제안한 프로토콜은 위성 자원 할당 정보를 이용하여 최적의 TCP CWND 크기를 설정하기 때문에 단일 및 다중 세션 환경에서 기존 TCP 보다 제안한 프로토콜이 더 좋은 성능을 보여준다는 것을 확인할 수 있었다.

• Tribology and Lubricants
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• 제37권3호
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• pp.99-105
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• 2021

In this study, for a high-pressure turbine (HPT) of 800 MW class supercritical thermal-power plant, considering aerodynamic cross-coupling, we performed a rotordynamic logarithmic decrement (LogDec) stability analysis with various tilting pad journal bearing (TPJB) designs, which several steam turbine OEMs (original equipment manufacturers) currently apply in their supercritical and ultra-supercritical HPTs. We considered the following TPJB designs: 6-Pad load on pad (LOP)/load between pad (LBP), 5-Pad LOP/LBP, Hybrid 3-Pad LOP (lower 3-Pad tilting and upper 1-Pad fixed), and 5-Pad LBPs with the design variables of offset and preload. We used the API Level-I method for a LogDec stability analysis. Following results are summarized only in a standpoint of LogDec stability. The Hybrid 3-Pad LOP TPJBs most excellently outperform all the other TPJBs over nearly a full range of cross-coupled stiffness. In a high range of cross-coupled stiffness, both the 6-Pad LOP and 5-Pad LOP TPJBs may be recommended as a practical conservative bearing design approach for enhancing a rotordynamic stability of the HPT. As expected, in a high range of cross-coupled stiffness, the 6-Pad LBP TPJBs exhibit a better performance than the 5-Pad LBP TPJBs. However, contrary to one's expectation, notably, the 5-Pad LOP TPJBs exhibit a slightly better performance than the 6-Pad LOP TPJBs. Furthermore, we do not recommend any TPJB design efforts of either increasing a pad offset from 0.5 or a pad preload from 0 for the HPT in a standpoint of stability.