• 한국멀티미디어학회논문지
• /
• 제25권11호
• /
• pp.1564-1571
• /
• 2022

Wireless sensor network(WSN) is being used in various fields such as reconnaissance, echelon scale identification, weather observation, etc. using small sensors in an environment without a network infrastructure environment. In addition, WSN uses limited battery power, so study on routing protocols to extend the lifetime of the network is important. PEGASIS, a hierarchical routing protocol, accounts for the majority of energy-efficient routing protocol studies and is well known as a representative protocol. In this study, based on PEGASIS, we propose a protocol that constructs multiple chains rather than one chain using the AoA of nodes. The proposed protocol has the advantage of reducing the transmission distance of nodes and eliminating unnecessary transmissions, thereby increasing energy efficiency compared to the existing protocols.

• 한국지구과학회지
• /
• 제35권4호
• /
• pp.249-258
• /
• 2014

대기 중 이산화탄소 등의 농도가 지속적으로 증가하고 있음에도 최근 10여 년 동안(2002-현재) 전지구 지표 온도는 거의 답보상태에 머물러 있다. 이처럼 온실기체 강제력에도 불구하고, 지구 온난화 경향이 사라진 듯 보이는 현상을 지구 온난화 멈춤(hiatus)이라 한다. 이 연구는 HadGEM2-AO가 모의한 RCP8.5 시나리오 실험(95년간) 자료를 분석하여, 온난화 멈춤 시기의 특징을 분석하였다. 온난화 멈춤 기간을 나타내는 시계열은 동서 평균한 연직 해수 온도 분포를 EOF 분석하여 구한 두 번째 PC (PC2)로 정의하였다. PC2를 이용하여 온난화 멈춤과 엔소와의 관련성, 기후시스템의 변화 등을 분석하였다. 라니냐 지수(NINO3지수에 -1을 곱하여 정의)가 PC2를 약 11개월 앞서는 것으로 보아 라니냐 발생이 온난화 멈춤을 유도할 수 있음을 발견하였다. 또한 기후시스템의 냉각은 해수 표층의 열이 해양 내부로 침강으로 나타남을 보였다. 이는 해양의 열흡수에 의해 전지구 온도 상승률이 약화되었음을 의미한다. 온난화 멈춤 시기에 북태평양과 북반구 극지는 양의 온도 편차가 나타났으며, 열대 해양에서는 무역풍이 강화되었다.

• 동아시아식생활학회지
• /
• 제24권3호
• /
• pp.325-334
• /
• 2014

The effects of aloe on liver function and lipid metabolic disorders induced by alcohol consumption were studied in rats using aloe power (0.25%, 0.5%, 1%) and 10% ethanol. 35 Sprague-Dawley (male, 4 weeks old) rats were divided into five groups and fed experimental diets for six weeks. Body weights of rats tended to be lower in all alcohol supplemented groups than in the control. Food intakes and dry feces per day were significantly lower in all alcohol supplemented groups than in the control. Atherogenic indices (AI) were highest in the alcohol group and decreased in proportion with aloe amount. Serum triglyceride level was significantly higher in the alcohol group than in the control, but tended to be lower in the aloe supplemented groups. In relation to liver function, glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), and alkaline phosphatase (ALP) activities tended to be higher in the alcohol groups than in the control, but lower in the aloe groups, especially in the alcohol+0.5% AO group. The levels of liver cholesterol were significantly lower in the alcohol group than in the control and aloe supplemented groups. In the histochemical evaluation, fat droplets appeared extensively on the liver-lobule in the alcohol group, whereas they decreased slightly in the alcohol+0.25% AO group and apparently disappeared in the alcohol +0.5% AO. On the other hand, fat droplets appeared again on the liver-lobule in the alcohol+1% AO group, but were reduced compared with the alcohol group. Regarding the fatty acid composition of adipose tissue triglycerides, the level of linoleic acid (18:2) was significantly higher in the aloe supplemented group. Regarding the fatty acid composition of liver phosphatidylcholine (PC), the level of linoleic acid was higher in the alcohol group and alcohol+1% AO group than the other groups. In contrast, the level of arachidonic acid was significantly lower in the alcohol group. As a result, arachidonic / linoleic acid ratios were significantly lower in the alcohol group compared to the control group, whereas the ratios of the aloe supplemented groups were similar to that of the control group. Therefore, aloe had some beneficial effects on lipid metabolic disorders induced by alcohol and affected desaturation of fatty acids.

• Journal of Korean Neurosurgical Society
• /
• 제64권5호
• /
• pp.776-783
• /
• 2021

Objective : The purpose of this study was to identify risk factors for distal adding on (AO) or distal junctional kyphosis (DJK) in adolescent idiopathic scoliosis (AIS) treated by posterior spinal fusion (PSF) to L3 with a minimum 2-year follow-up. Methods : AIS patients undergoing PSF to L3 by two senior surgeons from 2000-2010 were analyzed. Distal AO and DJK were deemed poor radiographic results and defined as >3 cm of deviation from L3 to the center sacral vertical line (CSVL), or >10° angle at L3-4 on the posterior anterior- or lateral X-ray at ultimate follow-up. New stable vertebra (SV) and neutral vertebra (NV) scores were defined for this study. The total stability (TS) score was the sum of the SV and NV scores. Results : Ten of 76 patients (13.1%) were included in the poor radiographic outcome group. The other 66 patients were included in the good radiographic outcome group. Lower Risser grade, more SV-3 (CSVL doesn't touch the lowest instrumented vertebra [LIV]) on standing and side bending films, lesser NV and TS score, rigid L3-4 disc, more rotation and deviation of L3 were identified risk factors for AO or DJK. Age, number of fused vertebrae, curve correction, preoperative coronal/sagittal L3-4 disc angle did not differ significantly between the two groups. Multiple logistic regression results indicated that preoperative Risser grade 0, 1 (odds ratio [OR], 1.8), SV-3 at L3 in standing and side benders (OR, 2.1 and 2.8, respectively), TS score -5, -6 at L3 (OR, 4.4), rigid disc at L3-4 (OR, 3.1), LIV rotation >15° (OR, 2.9), and LIV deviation >2 cm from CSVL (OR, 2.2) were independent predictive factors. Although there was significant improvement of the of Scoliosis Research Society-22 average scores only in the good radiographic outcome group, there was no significant difference in the scores between the groups. Conclusion : The prevalence of AO or DJK at ultimate follow-up for AIS with LIV at L3 was 13.1%. To prevent AO or DJK following fusion to L3, we recommend that the CSVL touch L3 in both standing and side bending, TS score is -4 or less, the L3/4 disc is flexible, L3 is neutral (<15°) and ≤2 cm from the midline and the patient is ≥ Risser 2.

• 산업경영시스템학회지
• /
• 제35권2호
• /
• pp.113-123
• /
• 2012

In this paper, it is examined how the amount of review time per applicant to a college admission officer system is connected with the performance of the selected students after they enter the college. About five years ago, college admission officers system has been introduced to Korea as a government policy. Thus, for most Korean college, there is not enough number of admission officers, while it takes substantial time to find out whether an applicant has potential ability or not. Thus, it is required to find out some policy alternatives to solve this discrepancy. In this paper, a simulation model is built using System Dynamics theory and simulated to understand the relation between the amount of review time and the performance of the selected students. Finally, some implications and policy suggestions are derived from the simulation results.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2007년도 춘계학술발표대회
• /
• pp.1237-1239
• /
• 2007

This paper proposes a virtual storage system for smart home/office embedded devices by utilizing AoE and HyperSCSI protocols. It relies on current Ethernet infrastructures and aims to provide a low-cost solution for the storage limitation problem on embedded devices. We choose AoE (ATA over Ethernet) and HyperSCSI in our implementation because they are relatively lightweight compared to other network storage protocols such as NFS(Network File System), CIFS(Common Internet File System) and iSCSI(internet Small Computer System Interface). The design and architecture of our proposed virtual system as well as the prototype demonstration are presented in this paper.

• Journal of Applied Biological Chemistry
• /
• 제57권1호
• /
• pp.53-59
• /
• 2014

Aspergillus oryzae로 발효시킨 청미래덩굴잎 용매추출분획물의 xanthine oxidase (XO) 및 aldehyde oxidase (AO) 저해활성과 항고요산혈증에 미치는 영향을 조사하였다. 용매별 추출수율(g/kg)은 80% ethanol (EtOH)은 13.56이었으며, n-hexane, dichloromethane (DICM), ethylacetate (EtOAc) 및 n-butanol fraction (BuOH)은 1.35-3.33 범위였다. Total polyphenol 함량(mg/g-extract)은 EtOAc fraction 478.07-501.26, BuOH fraction 259.49-289.02, DICM fraction 165.03-232.27, EtOH fraction 134.02-196.54이었으며 EtOAc 및 DICM fraction에서는 발효시킨 경우가 비발효에 비하여 각각 4.85 및 40.74%가 높았으나 그 외 모든 fraction에서는 발효시킨 경우가 낮았다. 총 flavonoid 함량은 EtOAc fraction이 여타 fraction에 비하여 높았다. EtOAc 및 BuOH fraction의 TF 함량은 발효시킨 경우가 비 발효에 비하여 각각 10.56% 및 60.17%가 높았으나 여타 fraction들에서는 발효시킨 경우가 낮았다. XO 저해활성은 모든 분획물에서 발효시킨 경우가 비발효에 비하여 현저하게 높았으며 EtOAc 및 BuOH fraction의 경우 발효시킨 경우는 각각 75.02 및 65.59%로 비발효 경우 39.42 및 5.34% 보다 현저하게 높았다. AO 저해활성은 DICM과 EtOAc fraction에서 각각 81.82 및 77.93%로 여타 fraction들에 비하여 높았으며 XO의 경우와 마찬가지로 발효시킨 경우가 비발효에 비하여 현저하게 높았다. 고요산혈증 mouse의 혈중 요산(SU) 함량에 미치는 영향을 조사한 결과, 고요산혈증 대조군의 SU 함량은 6.98 mg/dL로 정상대조군 (NC)의 3.82 mg/dL에 비하여 1.83배가 높았으나, EtOAc fraction은 투여량에 의존적으로 SU의 함량이 감소하였으며, 발효시킨 경우가 비발효에 비하여 유의적인 감소를 보였다. 이상의 결과, A. oryzae와 청미래덩굴잎의 발효과정을 통해, glycoside형태의 flavonoid를 aglycone화하여 비발효에 비해 높은 XO 및 AO 저해활성과 함께 항고요산혈증 효과를 나타내는 것으로 사료된다.

• 정보처리학회논문지C
• /
• 제16C권5호
• /
• pp.615-620
• /
• 2009

오늘날 무선 장비들이 센서네트워크를 비롯한 매우 다양한 분야에서 광범위하게 사용되고 있다. 무선으로 연결된 센서들은 다양한 임무 수행을 위하여 많은 분야에서 활용되고 있다. 이런 임무를 수행하는데 있어 각 센서의 위치정보는 매우 중요한 시스템 관리의 요소가 된다. 센서노드간 거리 측정은 신호의 도착시간차(Time of Arrival; ToA), 신호세기(Received Signal Strength: RSS), 신호각도(Angle of Arrival: AoA)에 기반을 둔 방법 등이 있다. 무선 센서네트워크에 배치되어 있는 각 센서노드간 정확한 거리 식별을 위해 기존의 거리 측정 방법을 보완하여 거리 오차를 줄이는 ToA기반의 RSS보정 방법을 제안한다. 구체적으로 초음파를 통한 거리측정 값에 맵(RF-MAP)을 통해 보정한 RSS값을 가중치로 보정하여 기존의 거리 측정 방법보다 측정오차를 감소시킬 수 있었다. 실험을 통해 본 연구 방법이 기존 ToA보다 실내($5m{\times}7m$)에서 평균 0.1cm, 실외($10m{\times}10m$) 평균 0.6cm 측정 오차를 줄일 수 있음을 확인 할 수 있었다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2002년도 학술대회지
• /
• pp.751-754
• /
• 2002

The SFU(Solid Fuel Ram-Jet) propulsion is attractive for projectiles because of the combination of high propulsive performance and low system complexity more than conventional projectiles. The Objective of this research was to characterize the inlet aerodynamic characteristics (centerbody & pilot type) in SFRJ. Diffuser static pressure & combustion chamber pressure was tested and the AoA was changed $0^{\circ}\;and\;4^{\circ}$ at Mach number of 3.0 for performance estimate. The performance study of inlet was carried out with the Schlieren system and Supersonic cold-flow system. A Computational fluid dynamic solution is applied internal flow of inlet and the solutions are compared with experimental results.

• 천문학회보
• /
• 제38권1호
• /
• pp.69.1-69.1
• /
• 2013

We are developing Adaptive Optics (AO) system for 1m telescope at Gwacheon National Science Museum Observatory. The beam spot of the Gwacheon 1m telescope. The tip-tilt correction system consists of a CMOS sensor, a tip-tilt mirror and a feed back loop. The beam spot location at the CMOS sensor indicates the tip-tilt components of the incoming light. The tip-tilt mirror is controlled by DAC output voltage calculated by proportional-integral-derivative (PID) controller. This system successfully corrects the tip-tilt motion of the spot.