• 비파괴검사학회지
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• 제32권4호
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• pp.355-361
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• 2012

This paper presents an experimental study on the detection and location of nonlinear scattering source due to the presence of fatigue crack in a laboratory specimen. The proposed technique is based on a combination of nonlinear elastic wave spectroscopy(NEWS) and time reversal(TR) focusing approach. In order to focus on the nonlinear scattering position due to the fatigue crack, we employed only one transmitting transducer and one receiving transducer, taking advantage of long duration of reception signal that includes multiple linear scattering such as mode conversion and boundary reflections. NEWS technique was then used as a pre-treatment of TR for spatial focusing of reemitted second harmonic signal. The robustness of this approach was demonstrated on a cracked specimen and the nonlinear TR focusing behavior is observed on the crack interface from which the second harmonic signal was originated.

• 전기전자학회논문지
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• 제25권3호
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• pp.571-577
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• 2021

본 논문에서는 자율주행자동차의 안전성 및 보안성을 보장하기 위해서 설계하고 검증하는 방법을 규정한 국제 표준인 ISO/TR 4804에 대해 다룬다. ISO/TR 4804는 자율주행자동차가 (1) 인간 운전자보다 훨씬 더 안전하고 (2) 타당하지 않은 위험이 없도록 하는 것을 목표로 하며, 이를 위해 12개의 안전성 및 보안성 원칙을 제시한다. 설계 과정에서는 (1) 안전성 및 보안성 원칙을 달성하는데 필요한 13개의 역량, (2) 이 역량을 수행하기 위해 필요한 하드웨어 및 소프트웨어 요소, (3) 이 요소를 결합한 논리적, 일반적인 아키텍쳐 등을 규정한다. 검증 과정에서는 (1) 안전성 및 보안성을 검증하기 위한 5개의 과업, (2) 이 과업을 완수하기 위한 테스트 목표, 플랫폼, 솔루션, (3) 시뮬레이션 방법 및 필드 운영 방법, (4) 하드웨어 및 소프트웨어 요소의 검증 방법 등을 규정한다. 특히 심층 신경망을 하나의 소프트웨어 요소로 간주하고, 심층 신경망이 적용된 자율주행자동차를 설계하고 검증하는 방법을 규정한다.

• 전기전자학회논문지
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• 제25권2호
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• pp.322-329
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• 2021

본 연구에서는 열처리 후 Island 표면 구조를 가지는 고분자 Poly(vinylidenefluoride-co-trifluoroethylene) [P(VDF-TrFE)]를 사용하여 유기 발광 다이오드의 광추출 효율을 향상시키기 위한 방법을 제시하였다. Island 구조의 P(VDF-TrFE) 표면 위에 임프린트한 polydimethylsiloxane (PDMS)는 Spike 구조를 띄고 이를 통해 전류 및 외부양자 효율을 약 20%을 향상시켰다. 제작된 필름은 8.2의 낮은 Haze특성을 보이며, 93.4% 우수한 투과도 특성으로 인해 Pixel blur 없이 광효율을 향상시킬 수 있음을 확인하였다.

• Journal of Chest Surgery
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• 제26권3호
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• pp.196-203
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• 1993

Fourty-five cases of operation were performed for the correction of tricuspid regurgitation [TR] in Pusan National University Hospital between 1982 and 1991.The mean age of the patients was 32.6 years and female was dominant[M:F=1:2.2].Isolated tricuspid regurgitation was rare and 43 patients underwent concomitant other valvular operation including mitral valve replacement. Functional cause was in 39 cases and organic lesions were found in 6 cases. Operative methods were Kay annuloplasty[29], De Vega annuloplasty[12], and tricuspid valve replacement[4]. Ring annuloplasty was not performed. Operative mortality rate was 11.1%[5/45] and late mortality rate was 6.7%[2/30]. The tricuspid valve surgery itself was not a serious risk factor for hospital death and no heart block nor thrombosis was complicated. By echocardiogram early[within 30 days] and late [mean:4.9years] changes of postoperative TR were evaluated. De Vega annuloplasty seemed to bring better late result than Kay annuloplasty[p<0.05]. In four patients with late severe TR,previously replaced tissue valve degeneration[2], pulmonary hypertension[1] and rheumatic TR[1] were the possible causes. This experience suggests that De Vega annuloplasty can be a reliable method in the majority of patients with moderate-to-severe functional TR.

• The Journal of Korean Physical Therapy
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• 제28권6호
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• pp.393-397
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• 2016

Purpose: This study was conducted in an effort to determine the effects of various abdominal drawing-in maneuver (ADIM) on the thickness and length of the transversus abdominis (TrA) when using lumbar stabilization exercises on healthy adults. Methods: 72 healthy adults were divided into four groups of 18 subjects each, to which different ADIM methods were applied. 1) a simple ADIM exercise, 2) an ADIM with pressure bio-feedback units, 3) an ADIM exercise with sling, and 4) an ADIM exercise with sling and vibration. Changes in the thickness and sliding length of TrA were measured when ADIM was conducted in the supine position prior to exercise and again when beginning the exercises. Following exercise, changes in the thickness and sliding length of TrA were measured using the same methods. Differences in group measurements prior to and following exercise were compared using a one-way analysis of variance. A paired t-test was applied to compare the before and after differences within each group. Results: Differences in TrA thickness change revealed that the ADIM exercise with sling and vibration group showed a significant difference in measurements taken prior to and following exercise. Differences in TrA length change revealed that the ADIM exercise with sling and vibration group showed a significant difference in measurements taken prior to and following exercise. Conclusion: ADIM exercise with vibration stimulation conducted in the bridge posture while in a prone position using a sling can be recommended as an effective exercise to improve the function of lumbar TrA.

• Journal of Chest Surgery
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• 제51권2호
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• pp.92-99
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• 2018

Background: We evaluated the early clinical outcomes of tricuspid valve annuloplasty (TAP) with the Tri-Ad annuloplasty ring for functional tricuspid regurgitation (TR). Methods: From January 2015 to March 2017, 36 patients underwent TAP with a Tri-Ad ring for functional TR. To evaluate the early clinical outcomes of TAP with the Tri-Ad ring, we conducted a propensity score-matched analysis comparing the Tri-Ad and $MC^3$ tricuspid annuloplasty rings (n=34 in each group). The follow-up duration was $11.0{\pm}7.07$ months. Results: There was 1 case of operative mortality (2.8%) and no cases of late mortality. Postoperative complications occurred in 15 patients (41%), including acute kidney injury in 6 patients (16%), bleeding requiring reoperation in 4 patients (11%), and low cardiac output syndrome in 4 patients (11%). There were no ring-related complications, such as atrioventricular block or ring dehiscence. The TR grade decreased significantly (from $2.03{\pm}1.06$ to $1.18{\pm}0.92$, p<0.01), as did the systolic pulmonary artery pressure (from $43.53{\pm}13.84$ to $38.00{\pm}9.72mm\;Hg$, p=0.03). There were no cases of severe residual TR, but moderate TR was observed in 3 patients, all of whom had severe TR preoperatively. Severe preoperative TR was also associated with moderate in the univariate analysis (p<0.01). In the propensity score-matched analysis comparing the Tri-Ad and $MC^3$ rings, there was no significant difference in early clinical outcomes. Conclusion: TAP with the Tri-Ad ring corrected functional TR effectively and provided good early clinical and echocardiographic results without ring-related complications. However, severe preoperative TR was associated with moderate or severe residual TR in the immediate postoperative period. A follow-up study is necessary to confirm the stability of this procedure.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.370-375
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• 1998

The objectives of this study are to evaluate the applicability of SCS TR-20 model for small ungauged watershed, to show the behavior of the model with variation of topography in watershed, and to evaluate the storage effect of paddy field for flood flow. For this purpose, simulated data from the model were compared with the observed flood data at two sites (HS#3, HS#4) in Balan watershed. From the comparison between simulated and observed data, it was found that the model is applicable to this watershed.

• 한국임상수의학회지
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• 제27권6호
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• pp.693-697
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• 2010

본 연구는 총 4두의 삵에서 발정기와 비발정기, 임신기와 비임신기 동안의 분변에서 steroid metabolic materials를 추출한 후, TR-FIA kit를 이용하여 estradiol과 progesterone의 농도를 측정하였다. 발정기간 (2월) 중 estradiol 농도의 최저는 평균 $4.02{\pm}1.9$ng/g 이었고, 최고는 평균 $86.01{\pm}35.2$ng/g (dry fecal weight) 이었다. 비발정기(11월)의 최저는 평균 $4.42{\pm}1.32$ng/g 이었고, 최고는 평균 $15.62{\pm}6.84$ng/g 이었다. 임신기 (3월) 중 progesterone농도의 최저는 평균 $427{\pm}24.49$ng/g 었고, 최고는 평균 $1490{\pm}265.27$ng/g 이었다. 비임신기 (11월)의 progesterone의 최저는 평균 $71.25{\pm}29.61$ng/g 이었고, 최고는 평균 $291.75{\pm}90.30$ng/g 이었다. 위의 결과에 따라 삵에서 TR-FIA에 의한 분변내 steroid hormone 의 측정은 발정과 임신에 관련된 난소활동을 비 침습적으로 평가하기 위한 적절한 방법으로 판단되었다. 본 연구는 삵과 같이 접근이 어렵고 멸종위기에 처한 야생동물의 사육관리의 효율화와 번식계획의 수립에 도움이 될 것이다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.655-658
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• 2004

Heat stress is known to affect physiological systems in goats. This study investigated changes in nutrient digestibility, behavior and growth hormone secretion among goats in a hot environment (H; 35${\pm}$ 1.2$^{\circ}C$, [RH] 80${\pm}$7.2%, 13 d), and in a thermoneutral environment (T; 20${\pm}$0.6$^{\circ}C$, [RH] 80${\pm}$3.4%, 20 d), and accompanied by the same restricted diet as provided in the hot environment. The following results were obtained: rectal temperature and water intake were higher in the H treatment than in the T treatment or TR treatment, while hay consumption was lower. CP, NDF and ADF digestibility was highest in H treatment. Time spent eating in the H treatment was also the highest, followed in order by T treatment and TR treatment. Ruminating time was lower in H treatment than in T treatment or TR treatment, and reposing time was highest in the TR treatment. Growth hormone concentrations in T increased 4.5 h after feeding. In H, growth hormone concentrations increased 0.5 h after feeding. However, growth hormone concentrations were not changed following TR feeding. In conclusion, heat exposure in goats decreased feed intake, but increased digestibility. However, when goats in a thermoneutral environment received the same restricted feeding as they received in the hot environment, digestibility increased. Between the H treatment and TR treatment, the changes in digestibility were accomplished by coordinate changes in hormone secretion in order to maintain body homeostasis. To maintain energy balance under a hot temperature or a restricted feeding condition, goats may control their metabolism by changing growth hormone release.

• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.491-510
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• 2005

This study was performed to evaluate the effect of inorganic polyphosphate on bone formation in the calvaria of rabbit in the procedure of guided bone regeneration with bovine cancellous bone graft and titanium reinforced expanded polytetrafluoroethylene(TR-ePTFE) membrane. The rabbits were divided into four groups. Control group I used only TR-ePTFE membrane, control group II used TR-ePTFE membrane and deproteinized bovine bone mineral soaked in saline, experimental group III and IV used TR-ePTFE membrane and deproteinized bovine bone mineral soaked in 1% or 2% inorganic polyphosphate respectively. After decortication in the calvaria, GBR procedure was performed on 12 rabbits with titanium reinforced ePTFE membrane filled with deproteinized bovine bone mineral soaked in saline or inorganic polyphosphate. The animals were sacrificed at 2 weeks, 4 weeks, and 8 weeks after the surgery. Decalcified and non-decalcified specimens were processed for histologic and immunohistochemistric analysis. 1. Titanium reinforced ePTFE(TR-ePTFE) membrane showed good spacemaking and cell occlusiveness capability, but it showed poor wound stabilization. 2. The deproteinized bovine bone mineral did not promote bone regeneration, but it acted as a space filler. 3. There was no complete resorption of the deproteinized bovine bone mineral within 8 weeks. 4. 1% inorganic polyphosphate did not promote bone formation, but 2% inorganic polyphosphate promoted bone formation. Within the above results, 2% inorganic polyphosphate could be used effectively for bone regeneration.