• Journal of Animal Science and Technology
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• 제46권5호
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• pp.707-718
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• 2004

오전(AM) 및 오후(PM)의 단얼 착유기록에 의한 유우의 1일 생산량 추청을 위한 통계적 모형에 대한 연구를 실시하였다. 본 연구에서 조사한 모형들 가운데， Model 7은 각 요인 조합 구간별로 개별적인 회귀식을 추정함으로써 산차， 착유시간 간격， 비유 단계에 따른 이분산성을 고려할 수 있기 때문에 평균 오차 제곱 합， 추정치와 실제 1일 유 생산량간의 상관계수 및 추정치의 분산을 고려할 때 가장 적합도가 높은 것으로 사료된다. 오후 착유 기록을 이용한 1일 유 생산량 추정치는 오전 착유 기록을 이용한 것보다는 정확도가 낮은 것을 나타났으며， Model 7의 경우 l일 유 생산량 추정을 위한 제반 요인이 추가되어 정확도가 높일수 있으면서도 모형이 간단하기 때문에 적용이 간펀한 장점이 있다.

• 한국물환경학회지
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• 제20권3호
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• pp.281-289
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• 2004

Optimal analytical conditions have been established for mixing and reaction coil length, concentrations of ECR, CTAB, and acetate, reaction temperature and pH in the determination of aluminum by using flow injection analysis(FIA). Detection limit and repeatability for this system were $3{\mu}g/L$ and better than 1% of relative standard deviation, respectively. The interference from iron(III) was suppressed up to 6mg/L of iron(III) by $0.1{\mu}M$ ascorbic acid, and the interference from fluoride could be tolerated in absorption of Al/ECR/CTAB derivative by 10mM boric acid at pH 3.5 adjusted with nitric acid. This FIA system was applied to the determination of aluminum leached from cooking utensils by distilled and tap water containing fluoride ranged from 0.5 to 2mg/L by measurement of absorbance for Al/ECR/CTAB at 585nm. The leached aluminum content was increased with increasing concentration of fluoride. The aluminum contents leached from aluminum utensils by tap water were about 9 fold higher than those leached by distilled water, whereas aluminum contents leached by distilled water containing fluoride were about 2 fold higher compared to those leached by distilled water. That represented that other dissolved substances as well as fluoride in tap water contributed to liberation of aluminum from aluminum utensils. A comparison between FIA data and ICP-AES data by correlation and paired t test showed that the FIA system could be accepted as a good alternative method for the determination of aluminum in tap water.

• Journal of Korean Neurosurgical Society
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• 제60권4호
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• pp.417-423
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• 2017

Objective : Repair of sensorial nerve defect is an important issue on peripheric nerve surgery. The aim of the present study was to determine the effects of sensory-motor nerve bridging on the denervated dermatomal area, in rats with sensory nerve defects, using a neural cell adhesion molecule (NCAM). Methods : We compared the efficacy of end-to-side (ETS) coaptation of the tibial nerve for sural nerve defect repair, in 32 Sprague-Dawley rats. Rats were assigned to 1 of 4 groups : group A was the sham operated group, group B rats had sural nerves sectioned and buried in neighboring muscles, group C experienced nerve sectioning and end-to-end (ETE) anastomosis, and group D had sural nerves sectioned and ETS anastomosis was performed using atibial nerve bridge. Neurological evaluation included the skin pinch test and histological evaluation was performed by assessing NCAM expression in nerve terminals. Results : Rats in the denervated group yielded negative results for the skin pinch tests, while animals in the surgical intervention groups (group C and D) demonstrated positive results. As predicted, there were no positively stained skin specimens in the denervated group (group B); however, the surgery groups demonstrated significant staining. NCAM expression was also significantly higher in the surgery groups. However, the mean NCAM values were not significantly different between group C and group D. Conclusion : Previous research indicates that ETE nerve repair is the gold standard for peripheral nerve defect repair. However, ETS repair is an effective alternative method in cases of sensorial nerve defect when ETE repair is not possible.

• 한국해안·해양공학회논문집
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• 제31권5호
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• pp.305-313
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• 2019

최근 해수면상승이나 해상조건의 악화 등으로 인해 연안보존을 위한 해안구조물 수가 급격히 증가하고 있다. 해안구조물은 소실되거나 제거되어서는 안 된다는 조건에서 관련된 해안 생태계를 충족하면서 해안공학적 특성을 만족하도록 계획이 이루어져야 한다. 본 연구에서는 이를 위해 사다리꼴 형태의 개비온블록을 개발하였으며 이동상 2차원 단면실험을 통해 타당성을 검토하였다. 실험은 8가지의 침식형 및 퇴적형 파랑에 대해 수행하였으며, 실험결과 개비온 블록이 해빈단면의 침식을 억제하는 특성이 있음을 확인하였다. 새롭게 고안된 개비온 블록에 대한 실험결과 해빈침식 대책공법의 대안으로 가능성이 있을 것으로 판단되었다.

• 한국추진공학회지
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• 제23권2호
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• pp.27-37
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• 2019

쉘-튜브 열교환기가 나로우주센터 추진기관종합시험장(PSTC)에 설치되었으며, 이 열교환기는 극저온의 헬륨을 고온의 열매유와 열교환하여 약 500 K 까지 가열시키는 역할을 한다. 열교환기에서 토출되는 헬륨의 온도가 설계보다 100 K 낮게 나옴에 따라, 성능저하의 원인으로 열매유의 격막효과가 지목되었다. CFD 해석을 통해 격막효과의 유무를 확인하였으며, 격막효과에 의한 열교환기 성능저하는 미미한 것으로 판단되었다. 추가적으로 열교환기의 성능을 증가시키기 위하여 열매유 교체에 따른 열교환기 성능 변화를 알아보았다. 열매유를 사용하는 열교환기의 성능향상을 위해서는 500 K 부근에서 점성이 낮아야 하고, 열전도도가 높아야 한다는 것을 확인할 수 있었다. 추진기관종합시험장에서 운용된 극저온 헬륨과 고온 열매유의 열교환 시스템의 시험 결과를 본 논문에서 확인할 수 있다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제20권6호
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• pp.387-395
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• 2020

Background: The anterior-middle superior alveolar (AMSA) anesthetic technique has been reported to be a less traumatic alternative to several conventional nerve blocks and local infiltration for anesthesia of the maxillary teeth, their periodontium, and the palate. However, its anatomic basis remains controversial. The present study aimed to determine if the pattern of cortical and cancellous bone density in the maxillary premolar region can provide a rationale for the success of the AMSA anesthetic technique. Method: Cone-beam computed tomography scans of 66 maxillary quadrants from 34 patients (16 men and 18 women) were evaluated using a volumetric imaging software for cortical and cancellous bone densities in three interdental regions between the canine and first molar. Bone density was measured in Hounsfield units (HU) separately for the buccal cortical, palatal cortical, buccal cancellous, and palatal cancellous bones. Mean HU values were compared using the Mann-Whitney U test and one-way ANOVA with post-hoc analysis. Results: Cancellous bone density was significantly lower (P ≤ 0.001) in the palatal half than in the buccal half across all three interdental regions. However, there was no significant difference (P = 0.106) between the buccal and palatal cortical bone densities at the site of AMSA injection. No significant difference was observed between the two genders for any of the evaluated parameters. Conclusions: The palatal half of the cancellous bone had a significantly lower density than the buccal half, which could be a reason for the effective diffusion of the anesthetic solution following a palatal injection during the AMSA anesthetic technique.

• 한국안전학회지
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• 제37권2호
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• pp.35-42
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• 2022

When an accident occurs, the associated human activity is typically regarded as a "human error," or a temporal deviation. On the other hand, if the accident results in a serious loss or if it evokes a social issue, the person determined to be responsible may be punished with a "violation" of related laws or regulations. However, as Heinrich stated, it is neither appropriate nor reasonable in terms of probability theory and cognitive science to distinguish whether it is a "human error" or a "violation" with a criterion of resultant accident severity. Nonetheless, some in society get on the social climate to strengthen regulations on workers who have caused accidents, especially violations. This response can present a social issue due to the lack of systematic judgment procedure which distinguishes violations from human errors. The purpose of this study was to develop an objective and systematic procedure to assess whether workers' activities which induced industrial accidents should be categorized as violations rather than human errors. Various analysis techniques for the determination of violation procedure were investigated and compared using an analysis approach method. An appropriate technique was not found, however, for judging the culpability of intentional violations. As an alternative, this study developed the process of creating violations, based on cognitive procedure, as well as the criteria to determine and categorize an activity as a violation. In addition, the developed procedure was applied to cases of industrial accidents and nuclear power plant issues to test its practical applicability. The study demonstrated that the proposed model could be used to determine the existence of a violation even in the case of multiple workers who work simultaneously.

• Journal of the Korean Wood Science and Technology
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• 제50권4호
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• pp.246-255
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• 2022

The need for non-destructive testing and evaluation of Korean traditional wooden buildings is increasing because of their widespread deterioration. Among all types of deterioration, termite damage in wooden columns is the most difficult to detect with the naked eye because it starts inside the wood, and the initial deterioration is small. X-ray computed tomography (CT) is the best technology to investigate the inner state of wood that has less damage, but applying it to wooden columns between walls is challenging. Therefore, the feasibility of tomosynthesis, which is a method to reconstruct a coronal section of a subject with a few X-ray projections from a limited angle of rotation, was studied as an alternative to CT. Pine (P. densiflora) with three artificial holes was prepared as a specimen to evaluate the quality of reconstructed tomosynthesis images according to the different number of projections. The quality of the tomosynthesis images in the in-focus plane was evaluated using the contrast-to-noise ratios, while a vertical resolution between the images was assessed by determining the artificial spread function. The quality of the tomosynthesis image in the in-focus plane increased as the number of projections increased and then remained constant as the number of projections reached 21 or over. In the case of vertical resolution, there was no significant difference when 21 projections or more were used to reconstruct the images. A distinct difference between coronal section images was found when the distance was more than 10 mm from one plane to another plane.

• 한국컴퓨터정보학회논문지
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• 제27권9호
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• pp.33-40
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• 2022

본 연구는 판넬형 공장 지붕의 드론 촬영 이미지를 분석해 볼트의 이상 탐지를 수행하는 시스템을 제안한다. 지붕의 점검은 현재 점검자가 직접 지붕 위로 올라가 점검을 진행한다. 하지만 고소 작업 환경으로 인한 안전사고가 지속해서 발생하고 있어 새로운 대안이 필요하다. 이에, 최근 위험 환경의 점검 방안의 대안으로 대두되는 드론 촬영의 결과물을 딥러닝을 이용해 이상 볼트의 위치를 찾아내는 방안을 통해 손쉽게 점검할 수 있도록 한다. 본 연구에서 제안하고 있는 시스템은 촬영된 드론 이미지를 볼트캡이 풀려있는 상황에 대한 샘플 이미지를 사용해 스캐닝을 진행한다. 더 나아가 스캔 된 위치에 대해 AI를 사용해 판별해 정확하게 볼트 이상 여부를 판별한다. 본 연구에서 사용한 AI는 VGGNet 기반으로 정확도 99%의 테스트 결과를 보였다.

• Earthquakes and Structures
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• 제23권5호
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• pp.473-491
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• 2022

The research investigates experimentally the effect of confinement on structural behavior at the ends of beam-column in reinforced concrete (RC) frames. In the experimental study, five specimens consisting of 1/3-scaled RC frames having single-bay, representing the traditional deficiencies of existing buildings constructed without receiving proper engineering service is investigated. The RC frame specimens were produced to represent most of the existing buildings in Turkey that have damage potential. To decrease the probable damage to the existing buildings exposed to earthquakes, the carbon Textile Reinforced Mortar (TRM) strengthening technique (fully wrapping) was used on the ends of the RC frame elements to increase the energy dissipation and deformation capacity. The specimens were tested under reversed cyclic lateral loading with constant axial loads. They were constructed satisfying the weak column-strong beam condition and consisting of low-strength concrete, such as compressive strength of 15 MPa. The test results were compared and evaluated considering stiffness, strength, energy dissipation capacity, structural damping, ductility, and damage propagation in detail. Comprehensive investigations of these experimental results reveal that the strengthening of a brittle frame with fully-TRM wrapping with non-anchored was effective in increasing the stiffness, ductility, and energy dissipation capacities of RC bare frames. It was also observed that the frame-only-retrofitting with an infill wall is not enough to increase the ductility capacity. In this case, both the frame and infill wall must be retrofitted with TRM composite to increase the stiffness, lateral load carrying, ductility and energy dissipation capacities of RC frames. The presented strengthening method can be an alternative strengthening technique to enhance the seismic performance of existing or moderately damaged RC buildings.