• 한국지능시스템학회논문지
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• 제22권4호
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• pp.521-526
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• 2012

제조공정을 통해 생산된 화살의 성능은 화살의 이동궤적(궁사의 패러독스)과 탄착점의 집적도에 따라 좌우된다. 특히 동일한 환경에서 반복적으로 화살의 슈팅실험을 수행할 경우, 반복실험에서 얻어진 화살의 탄착점 집적도는 화살 성능 평가에서 중요한 객관적 지표가 된다. 그러나 화살의 탄착점에 대한 분석은 현재 상용화된 기술이 부족하며, 기존의 연구들은 화살의 성능에 영향을 미치는 제조공정 변수(화살깃, 화살촉, 화살의 곧기, 중량, 외경, 스파인)만을 최적화하려는 방향으로 기술력이 집중되어 있다. 본 논문에서는 화살의 주요성능지표인 화살의 탄착점 측정 자동화를 위해, Mamdani 퍼지 추론 시스템(Mamdani Fuzzy Inference System)과 도형의 닮음(Similarity of Polygon)을 이용한 화살의 탄착점 측정 시스템을 제안한다. 라인레이저(Line Laser)와 포토다이오드어레이(Photo Diode Array)를 이용하여 고속(약 275km/h)으로 이동하는 화살의 탄착점 데이터를 계측하고, 계측된 데이터를 퍼지 추론과 도형의 닮음을 이용하여 화살의 탄착점으로 사상(Mapping) 시킨다.

• Structural Engineering and Mechanics
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• 제27권5호
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• pp.609-623
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• 2007

The problem of a semi-infinite magneto-electro-elastically impermeable mode-III crack in a magneto-electro-elastic material is considered under the action of impact loads. For the case when a pair of concentrated anti-plane shear impacts, electric displacement and magnetic induction impacts are exerted symmetrically on the upper and lower surfaces of the crack, the magneto-electro-elastic field ahead of the crack tip is determined in explicit form. The dynamic intensity factors and dynamic energy density factor are obtained. The method adopted is to reduce the mixed initial-boundary value problem, by using the Laplace and Fourier transforms, into three simultaneous dual integral equations, one of which is converted into an Abel's integral equation and the others into a singular integral equation with Cauchy kernel. Based on the obtained fundamental solutions of point impact loads, the solutions of two kinds of different loading cases are evaluated by integration. For some particular cases, the present results reduce to the previous results.

• 지질공학
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• 제24권4호
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• pp.463-471
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• 2014

This paper considers the effect of rainfall on non-point source (NPS) pollutant loads. The impact of runoff on the occurrence of NPS pollutants was found to be influenced by rainfall amount, rainfall intensity, and the number of antecedent dry days (ADD), both independently and in combination. The close correlation ($R^2$ = 0.9920) between rainfall and runoff amounts was demonstrated at the study site (a flower farm) over the period between January 2011 and December 2013. The relationships among pollutant levels, runoff, and rainfall was not satisfactory results except for the Biochemical Oxygen Demand ($BOD_5$). The correlation coefficients between $BOD_5$, and both runoff and rainfall, were greater than 0.92. However, the relationships of other pollutants, such as Suspended Solid (SS), Chemical Oxygen Demand ($COD_{Mn}$), Total Nitrogen (TN), and Total Phosphorus (TP), with runoff and rainfall had correlation coefficients of less than 0.70. The roles of rainfall was different from rainfall categories on the occurrence of runoff. Instantaneous rainfall intensity was a principle factor on the occurrence of runoff following light rainfall events (total ${\leq}30mm$). For rainfall of intermediate intensity (total precipitation 31-50 mm), the combined effect of both average rainfall intensity and ADD was found to influence runoff generation. We conclude that the control of NPS pollutants with the reflection of the climate change that makes the remarkable effect of amounts and forms on the rainfall and runoff.

• 한국농공학회논문집
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• 제62권4호
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• pp.13-22
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• 2020

The Doam Lake watershed has a significant impact on the downstream water system due to nutrients and sediment outflow during rainfall caused by steep slopes, soil losses, and fertilization. These non-point sources are unclear in the discharge area and are affected by land use patterns, soil characteristics, and topographical features of the watershed. Therefore, this study conducted rainfall monitoring from July to October 2019 in Songcheon upstream of the Doam Lake watershed, one of the non-point pollution source management areas. Then, after analyzing rainfall runoff, Event Mean Concentration (EMC) and Mass First Flush ratio (MFFn) were calculated to compare and analyze the characteristics of rainfall and the non-point pollutant discharge. As a result of the analysis, it showed various non-point pollutant emission characteristics for each rainfall event. In addition, the concentration of EMC and the MFFn were affected by the average rainfall intensity and the maximum rainfall intensity, and were not significantly affected by the number of antecedent drying days. In the future, it is expected that effective non-point source reduction measures and management measures according to rainfall intensity through continuous monitoring and analysis will be needed.

• 환경영향평가
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• 제23권1호
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• pp.67-74
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• 2014

The aim of this study was evaluated the effects of total rainfall, rainfall intensity and antecedent dry days and identify the correlation analysis with the EMC removal efficiency, in order to provide an understanding of the operation and maintenance factors of constructed wetland in flood pumping station. This study was conducted total of 20 monitoring in a catchment(326.2 ha) of constructed wetland in Ga-un flood pumping station located at the downstream of the Wang-suk stream. The determined EMC removal efficiencies were $36.04{\pm}9.45%$ for BOD, $38.50{\pm}13.50%$ for $COD_{Mn}$, $34.34{\pm}13.05%$ for TN and $34.22{\pm}14.27%$ for TP, respectively. These results showed that the pollutants concentration and EMC were reduced while passing through the constructed wetland. In the correlation analysis, the highly correlations with EMC removal efficiency of BOD and $COD_{Mn}$ were observed for total rainfall and rainfall intensity (P<0.05). However, the correlations were not found with TN and TP for rainfall variables.

• 한국지능시스템학회논문지
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• 제24권5호
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• pp.548-553
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• 2014

제조공정을 통해 생산된 화살의 성능을 평가하기 위한 방법으로, 활과 화살을 오랫동안 사용해 온 사냥꾼이나 레저 스포츠 용품을 만드는 기술자, 그리고 전문가의 개인적인 경험 등이 사용된다. 또한, 반복슈팅실험을 통해 얻어진 화살의 탄착점 집적도는 생산된 화살의 성능을 평가하기 위한 중요한 지표이다. 탄착점 집적도와 초고속카메라를 통해 촬영된 비행중인 화살의 이미지를 이용하여, 화살의 성능에 대한 연구가 수행되고 있다. 하지만, 화살의 특성(길이, 무게, 스파인, 오버랩, 곧기)과 탄착점의 분포간의 상관관계에 대한 연구는 부족하다. 본 논문에서는 탄착점 분포를 수치적으로 출력할 수 있는 시스템을 개발하고, 생산된 화살이 가지는 특성과 탄착점 사이의 상관관계모델을 구현하는 것이 목적이다. 모델의 입력은 화살이 가지는 특성(스파인, 곧기)이 사용되고, 출력은 화살의 노크 각도를 120도씩 회전시키면서 3번 반복 슈팅하여 얻어지는 삼각형 모양 좌표의 MAD(mean absolute distance)를 이용하였다. 상관관계 모델을 구현하기 위해서 입출력 학습데이터를 수집하였고, 모델의 구현을 위해서는 인공신경회로망(Artificial neural network, ANN)을 사용하였다.

• 대한기계학회논문집A
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• 제26권5호
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• pp.904-913
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• 2002

In this paper, the dynamic stress intensity factors of fracture mechanics are numerically computed in time domain using the FEM. For which the finite element formulations are derived applying the Galerkin method to the equations of motion in convolution integral as has been presented in the previous paper. To assure the strain fields of r$^{-1}$ 2/ singularity near the crack tip, the triangular quarter-point singular elements are imbedded in the finite element mesh discretized by the isoparametric quadratic quadrilateral elements. Two-dimensional problems of the elastodynamic fracture mechanics under the impact load are solved and compared with the existing numerical and analytical solutions, being shown that numerical results of good accuracy are obtained by the presented method.

• Journal of Acupuncture Research
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• 제41권2호
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• pp.115-120
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• 2024

Background: Migraine is a common disabling headache that affects every aspect of a person's life. Auricular acupuncture is a cost-effective treatment modality for the management of painful neurological conditions. Previous studies have shown the beneficial effects of a combination of ear points in the management of migraines. However, no studies have evaluated the efficacy of a single auricular point (i.e., sympathetic point) in migraine. Thus, this study evaluated the efficacy of sympathetic points on pain intensity and depression levels in patients with migraine. Methods: In this randomized controlled study, 100 patients with migraine aged 18-45 years were randomly divided into either an auricular acupuncture group (AAG) (n = 50) or a placebo control group (PCG) (n = 50). The AAG underwent needling at the sympathetic point (an auricular acupuncture point), whereas the PCG underwent needling at a non-acupuncture point for 20 minutes daily for 7 days. Assessments were performed before and after the intervention using a 6-item headache impact test (HIT-6) and Beck depression inventory (BDI) scale. Statistical analyses were performed using SPSS version 16. Results: In within-group analysis, the AAG showed a significant reduction in HIT-6 and BDI, whereas the PCG showed a significant increase in HIT-6 and a significant reduction in BDI. In between-groups analyses, HIT-6 reduced significantly in the AAG compared with that in the PCG, whereas BDI reduced significantly in the PCG compared with that in the AAG. Conclusion: In patients with migraine, needling at the sympathetic point produces a greater reduction in the pain intensity level and lesser reduction in the depression level compared to needling at a non-acupuncture point.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.917-917
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• 2003

The auditory experiments based on the subjective annoyance responses were undertaken for the establishment of the adverb modifiers of the heavy-weight impact noises. The standard heavy weight impact noise, impact ball noise and adult walking noise were recorded by dummy head at a newly-built apartment and were presented to the subjects by headphones. The levels of the three impact noises were varied from 30 to 60㏈(A) and the subjects matched one of the adverb modifiers to each level of the noise sources. As a result, seven scale modifiers were established and the intervals between the modifiers were found as equal. In addition, it was found that the lower annoyance noise limits for the heavyweight impact, impact ball and walking were 40-45㏈ (L$\sub$I, Fmax. AW), which is 6㏈ lower than in the previous study. The background noise level was as low as 21㏈(A) in the test booth, therefore, the testing conditions need to be concerned for evaluation of floor impact noise.

• 한국습지학회지
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• 제22권1호
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• pp.1-7
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• 2020

비점오염은 수계에 악영향을 끼치며 그 영향은 점차 커지고 있다. 이러한 비점오염을 관리하기 위해 정부에서는 LID(Low Impact Development) 시설의 연구와 다양한 효율평가를 시행하고 있다. 본 연구에서는 다양한 LID 시설 중 실제 설치된 투수 블록 시설의 강우 유출 억제를 위한 유출 저감율, 저류 강우량 분석 및 유출 지연시간 그리고 최대 유입 및 유출의 저감율을 분석했으며, 그 결과를 각 시설 간 비교했다. 불투수블록, 필터형 투수블록, 틈새형 투수블록 순서대로 분석 결과 저감 효율이 높게 나타났으며, 이를 통해 강우강도-유출지연시간간의 관계를 나타낸 그래프를 제시하였다. 이 그래프를 통해 앞으로 설계 시, 본 시설과 유사한 투수블록 시설의 재현 기간에 따른 시설 용량 선정 등의 설계에 도움을 줄 수 있으리라 생각한다.