• 상하수도학회지
• /
• 제12권3호
• /
• pp.91-98
• /
• 1998

In this study, the hydrological changes due to urbanization were investigated and fundamental theory and characteristics of typical urban runoff model such as ILLUDAS was studied. Above model was applied for urbanizing Dongsucheon basin, Incheon. The main parameters (II, IA, IS) which are included in model depending on runoff results were determined, and dimensionless values such as total runoff ratio($Q_{TR}$), peak runoff ratio($Q_{PR}$), and runoff sensitivity ratio ($Q_{SR}=Q_{TR}/Q_{PR}$) were estimated in order to evaluate and compare the characteristics of model based on relative sensitivity analysis.

• 대한기계학회논문집B
• /
• 제31권8호
• /
• pp.688-693
• /
• 2007

To improve aerodynamic efficiency of the Smart Un-manned Aerial Vehicle(SUAV), vortex generator was applied along the wing upper surface during SUAV tests. Vortex generator, initially used in TR-S2 configuration to enhance lift characteristic, increased lift coefficient. Meanwhile vortex generator produced excessive drag and eventually reduced lift-to-drag ratio. To examine the effect of vortex generator's height, three different heights of vortex generator were used for various SUAV configuration. Vortex generator of 3mm height used in TR-S4 configuration produced 3.1% increase in maximum lift coefficient and 1.5% reduction in lift-to-drag ratio.

• 상하수도학회지
• /
• 제13권2호
• /
• pp.74-81
• /
• 1999

In this study, the hydrological changes due to urbanization were investigated and fundamental theory and characteristics of typical urban runoff model such as CHICAGO Model was studied. Above model was applied for urbanizing Dongsucheon basin, Incheon. The main parameters(CI, CP, CS) which are included in this model depending on runoff results were determined, and dimensionless values such as total runoff ratio($Q_{TR}$), peak runoff ratio($Q_{PR}$), and runoff sensitivity ratio($Q_{SR}=Q_{TR}/Q_{PR}$) were estimated in order to evaluate and compare the characteristics of model based on relative sensitivity analysis. Finally, applied model was proposed based on understanding of work types and established urban runoff models which can simulate well for areal development patterns and urban river basin.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 춘계학술대회 논문집
• /
• pp.694-695
• /
• 2013

An experimental study has been made with the use of time reversal concepts to recover the input waveform in a long range propagation of dispersive Lamb waves. Three techniques have been tested: Regular TR, 1 bit TR and Inverse filter (IF). The IF approach was found to completely recover the original input signal. Moreover, the IF technique significantly increases the contrast, i.e., the ratio of the recovered signal and the sideband signal.

• PNF and Movement
• /
• 제16권2호
• /
• pp.301-306
• /
• 2018

Purpose: This study aimed to describe and identify the relationship between gait and contracted ratios of the transverse abdominal (TrA), internal oblique (IO), and external oblique (EO) muscles. Methods: This study was conducted on 50 elderly people. The contracted ratios of the lateral abdominal muscles (LAM) were measured using the abdominal drawing-in maneuver (ADIM) and ultrasonographic imaging. Gait was measured using the timed up and go test and the 10 m walk test. Results: The contracted ratios of the TrA and IO muscles significantly increased after ADIM. Those of the TrA muscles showed a significant correlation with gait in the limited community ambulatory group. The contracted ratios of the IO and EO muscles showed a significant correlation with gait in the community ambulatory group. Conclusion: Our findings suggest a specific training on the relationship between gait speed and the activation of the LAM in elderly people.

• 한국통신학회논문지
• /
• 제30권4C호
• /
• pp.230-238
• /
• 2005

직교 주파수 분할 다중 접속(orthogonal frequency division multiplexing: OFDM) 시스템은 여러 부 반송파를 사용해 정보를 전송하기 때문에 각 부 반송파가 동위상으로 겹치면 최고 대 평균 전력 비율이 (peak-to-average power ratio: PAR) 커진다. 이 논문에서는 최고 줄임 톤을 (peak reduction tone: PRT) 사용한 PAR 감소 기법 가운데 하나로 부분 톤 선택 사상 (selective mapping of partial tones: SMOPT) 기법을 제안한다. 제안한 SMOPT 기법은 반복 수렴 알고리즘을 사용한 기존의 톤 예약 (tone reservation: TR) 기법보다 적은 복잡도로 구현이 가능하고, 최고 감소 부 반송파 위치에 덜 민감하다. 또한 병렬 구성이 가능하여 알고리즘 수행 시간을 단축 할 수 있다. 이 논문에서는 이를 검증하기 위해 두 가지 사례에 대한 모의실험 환경을 구성하고, 이에 따른 복잡도와 첨두 감소 부 반송파 위치, 그리고 송신 전력에 따른 PAR 감소 성능과 비트 오류율 (bit error rate: BER) 성능을 비교 분석한다.

• 대한통합의학회지
• /
• 제10권2호
• /
• pp.73-83
• /
• 2022

Purpose : Low back pain (LBP) is reported as a risk of experiencing musculoskeletal disorders due to muscle stiffness and hypokinetics. The lumbar spine in an unstable state causes imbalance and lumbar instability. Therefore, This study examined the effects of lumbar stabilization exercise and self-complex exercise program on pain, function, psychosocial level, static balance ability, and transverse abdominal muscle (TrA) thickness and contraction ratio in patients with lumbar instability. Methods : The design of this is a randomized controlled trial (RCT). Twenty-six LBP patients participated in this study. Screening tests were performed and assigned to the experimental group (n=13) and control group (n=13) using a random allocation program. Both groups underwent a lumbar stabilization exercise program. In addition, the experimental group implemented the self-complex exercise program. All interventions were applied three times per week for four weeks. The quadruple visual analog (QVAS), the Korean version of the Oswestry disability index (K-ODI), Korean version of fear-avoidance belief questionnaire (FABQ), static balance ability, TrA thickness, and contraction ratio were compared to evaluate the effect on intervention. Statistical significance was set at 𝛼=.05. Results : Both groups showed significant differences before and after the intervention in QVAS, K-ODI, FABQ, static balance ability, and TrA thickness in contraction (p<.05). In addition, significant differences in K-ODI and FABQ were observed between the experimental group and control group (p<.05). Conclusion : A lumbar stabilization exercise and self-complex exercise program resulted in reduced dysfunctions, psychosocial stability in patients with lumbar instability. Therefore, Lumbar stabilization exercise and self-complex exercise program for patients with lumbar instability are effective method with clinical significance in improving the function and psychosocial stability.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 추계학술대회논문집
• /
• pp.602-603
• /
• 2008

The design modification of problematic component in a given vibration path is disallowed in order to sacrifice other performances such as ride comport or handling of a vehicle. For this, the paper presents a new contribution analysis based on transmissibility ratio (TR) of acceleration in a definite vibration path to find a proper candidate for design modification. The new contribution analysis is based on the fact that the sensitivity of TR over a small design change is inversely proportional to the magnitude of TR. The new methodology can significantly relieve efforts of time-consumming modal analysis for detail modal information. The theory of proposed contribution analysis is simulated with five-degree-of-freedom open vibration path and confirms that the contribution result is well matched with the variance of TR over a dynamic change on a vibration path.

• PNF and Movement
• /
• 제15권1호
• /
• pp.51-56
• /
• 2017

Purpose: The purpose of this study was to examine the effects of the PNF stabilization technique for the hip joint and the bridging exercise on the trunk stabilizer muscles in healthy adults. Methods: Twenty-eight healthy adults were randomly allocated to either a PNF stabilization exercise group (n = 12) or a bridging exercise group (n = 16). The outcome measures included the contraction thickness ratio in the transversus abdominis (TrA), internal oblique (IO), and external oblique (EO), and the TrA lateral slide was assessed during the abdominal drawing-in maneuver using b-mode ultrasound. The researcher measured the abdominal muscle thickness of each participant before the therapist began the intervention and at the moment that the intervention was applied. Between-group comparisons were performed using the Mann-Whitney U test. The level of statistical significance was set at 0.05. Results: The PNF intervention program showed a significant increase in the trunk stabilizer muscle. The percentage of change in the TrA thickness showed a significant interaction between intervention. However, there were no significant differences in the IO and EO between the two groups. Conclusion: The PNF stabilization technique for the hip joint can be used effectively to improve the IO and TrA muscles in healthy adults.

• 한국광학회지
• /
• 제4권1호
• /
• pp.9-14
• /
• 1993

Amplitude filter와 phase filter가 결합된 CFAP(Combined Filter of Amplitude and Phase)의 결상 특성을 조사하기 위해 Bessel beam을 도입하였다. 이 논문에서는 무수차계와 수차를 포함하는 광학계에 대한 PSF와 encircled energy(E), transmission ratio(TR), gain(G)을 Bessel beam의 node수에 따라 계산하였다. 이 결과 Bessel beam은 amplitude filter와 다른 PSF 특성을 보였으며, 또한 구면수차가 포함된 경우 compensating effect가 크게 나타났다. 특히 Bessel beam의 central spot의 size가 Airy disk 반경보다 적게 나타나므로, 고집적 반도체 소자 제작에 이용가능하리라 생각된다.