• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.144-149
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• 2001

The failure at the head section of rubble-mound detached breakwaters is more important than other failure modes. because this initial failures will occur the failure of the trunk section and lead to the instability of the structure. The three-dimensional failure modes are discussed using the experimental data with multi-directional waves considering the failure modes occurring around the head of the rubble-mound detached breakwater. The spacial characteristics of failure mode around the rubble-mound structures can be summarized as follows: 1) It was clarified that the failure modes at the round head of a detached breakwater are classified as failure by plunging breaker on the slope, failure by direct incident wave force and failure by scouring at the toe of the detached breakwater. 2) The failure mode was found in the lower wave height than the design wave by the breaker depth effects. It is clarified that the structure monitored was safely designed for the design wave but the failure was occurred by the reason of breaker waves and scouring processes at the toe 3) It was observed that scouring at the toe developed in the region where steady stream due to vorticity was generated and the spatial variation of scour at the toe of the round head was predominated by incident wave direction.

• 한국안전학회지
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• 제25권6호
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• pp.22-27
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• 2010

Flow Coefficients of intake port in an engine cylinder head were measured by a newly designed flow rig. In measuring the flow coefficient with traditional method, the valve lift was manually varied by technician with adjusting a micrometer which is directly connected to the intake valve of the cylinder head. The cam shaft of the cylinder head is directly rotated by a step motor and the valve lift was automatically varied with cam shaft profile in the newly designed flow rig. The measurement of the flow coefficient was automated by rotating the cam shaft with the step motor. Automatic measurement of the flow coefficient could be safely measured by separating a technician from the noise and vibration of the traditional flow rig. Also, the automatic measurement of the flow coefficient reduce the measurement time and provide meaningful statistical data.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.39-44
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• 2022

Using a CFD (computational fluid dynamics) simulation tool, we have offered a design guideline of a slot-die head having a simple T-shaped cavity through an analysis of the fluid dynamics in terms of cavity pressure and outlet velocity, which affect the uniformity of coated thin films. We have visualized the fluid flow with a transparent slot-die head where poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is injected. We have shown that the fluid dynamics inside the slot-die head depends sensitively on the cavity depth, cavity length, land length, and channel gap (i.e., shim thickness). Of those, the channel gap is the most critical parameter that determines the uniformity of the pressure and velocity distributions. A pressure drop inside the cavity is shown to be reduced with decreasing shim thickness. To quantify it, we have also calculated the coefficient of variation (CV). In accordance with Hagen-Poiseuille's laws and electron-hydraulic analogy, the CV value is decreased with increasing cavity depth, cavity length, and land length.

• 한국전문물리치료학회지
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• 제12권4호
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• pp.41-47
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• 2005

The purpose of this study was to determine the intra-rater and inter-rater reliability of various forward head posture measurements. Ten healthy adults (age, $20.4{\pm}2.2$ yrs; height, $164.0{\pm}5.5$ cm; weight, $58.7{\pm}7.3$ kg) participated in the study. They were free of injury and neurologic deficits in the upper extremities and neck at the time of testing. The subjects were asked to perform head forward posture by under the guidance of physical therapists. Markers were placed on the C7 spinous process, mastoid process, tragus of the ear, outer canthus, and forehead. Measurement 1 for forward head posture assessment was measured as the angle between the horizontal line through C7 and the line connecting the C7 spinous process with the tragus of the ear. Measurement 2 was measured as the angle between the C7 spinous process, the mastoid process and the outer canthus. Measurement 3 was measured as two kinds of angles the HT (head tilt) angle is between the line from the midpoint of forehead to the tragus line and Y-axis at the tragus point. The NF (neck flexion) angle is between the line from the tragus to the C7 line and the Y-axis at the C7. Intra-rater, inter-rater reliability and coefficient of variation was assessed by comparing the measured values from three kinds of measurements of forward head posture. The intra-rater reliability was indicated by intraclass correlation coefficients [ICC(1,1)] and inter-rater reliability was shown by intraclass correlation coefficients [ICC(3,k)]. The results of study were as follows: ICC(1,1) values for intra-rater reliability of three measurements were in the 'excellent' category. ICC(3,k) values for inter-rater reliability of three measurements were also in the 'excellent' category. The coefficient of variation of method 2 had a lower value than method 1 and method 3. This data means that the measured value of method 2 was less scattered. Further research is needed to determine whether the validity of all measurements is revealed in the 'excellent' category.

• 한국수자원학회논문집
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• 제43권5호
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• pp.445-453
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• 2010

도시 우수 배수 시스템에서 우수 관거는 개수로 흐름 상태로 가정하여 설계되었기 때문에 합류맨홀에서의 에너지 손실은 일반적으로 중요하게 고려되지 않았다. 그러나 과부하흐름에서 에너지 손실은 관거의 배수능력을 저하시켜 도심지역의 침수피해를 가중시키는 요인이 된다. 그러므로 과부하 합류맨홀 내에서의 수두 손실을 분석할 필요가 있다. 본 연구에서는 합류맨홀에 대한 문헌조사 및 현장조사를 실시하여 실험장치를 제작하고 실험조건을 선정하였다. 선정된 실험조건인 맨홀 형상 조건(사각형, 원형), 유출유량($Q_3$)에 대한 측면유입유량($Q_2$)의 비($Q_2/Q_3$) 및 실험 유량(2.0, 3.0, $4.0{\ell}$/sec)을 변화시키면서 실험을 실시하였다. $Q_2/Q_3$가 증가할수록 손실계수가 증가하므로 과부하 합류맨홀에서의 손실계수는 측면 유입관로의 유입유량의 영향을 크게 받는다고 판단된다. 맨홀의 형상변화 및 유량변화에 따른 손실계수는 거의 동일하게 산정되었다. 또한, $Q_2/Q_3$와 손실계수의 관계식을 제시하였다.

• 한국유체기계학회 논문집
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• 제10권1호
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• pp.7-13
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• 2007

This study proposes a modified bifurcation model with a computational fluid analysis according to variation of a bifurcation geometry. FLUENT is used for a calculation of the head losses in case of a generation and a pumping. The pressure, velocity field and turbulent intensity are simulated in a bifurcation. With consideration about these flow properties, we propose the modified model to improve a flow efficiency and reduce a sound. The proposed model is able to cut down a head loss by 45% when a generation and 36% when a pumping.

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2008년도 제16차 학술대회
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• pp.162-162
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• 2008

Many anomalous origins of the long head of the biceps tendon (LHBT) have been reported. However, developmental anomalies of the LHBT are rarely encountered in daily practice. We report a patient with an anomalous LHBT that was adherent to and confluent with the rotator cuff throughout its intra-articular course and present the clinical, magnetic resonance arthrography, and arthroscopic findings.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.570-575
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• 2002

Servo performance of a disk drive is greatly affected by the mechanical resonance frequencies of the head gimbal assembly (HSA). It is important factor to allow broader bandwidths for servo system in improving overall drive performance. In this paper, an optimal design for ODD suspension is attempted to increase resonance frequencies in tracking direction. Initial model was designed and the design parameter was defined to the model. The mode frequency variation for the change of design parameter was observed by modal analysis using the finite element method(FEM). The sensitivity matrix was calculated from the observed data and so through sensitivity analysis, an optimized ODD suspension was designed to have the higher resonant frequency than the initial model.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권5호
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• pp.263-266
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• 2006

An optical microphone was developed using a dual-core multi-mode fiber block and a membrane type micromirror. The fiber block serves as a compact optical head, and the micromirror as a reflective diaphragm. The micromirror is designed to be suspended through a silicon bar connected t a frame, allowing for displacement induced by acoustic waves. The optical head is implemented by integrating two multi-mode fibers in a single block, and used to transfer light signals between it and the diaphragm. For the assembled microphone, its static characteristics were observed to reveal the operating point defined as the optimum distance between the optical head and the diaphragm. And its dynamic response was tested to exhibit a frequency bandwidth of 3 kHz with the variation of $\sim5dB$.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.251-256
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• 2021

Objective: The forward head posture (FHP) is strongly related to the rounded shoulder posture (RSP), which is associated with shoulder pain. Design: Observational cross sectional study design Methods: A total of 37 were enrolled in the study, 22 individuals with FHP(experimental group) and 15 healthy adults(control group). Correlation with differences between groups was analysed through craniovertebral angle (CVA) representing FHP for both groups, neck disability index (NDI) indicating neck pain, disability of the arm, shoulder and hand (DASH) indicating shoulder pain. Results: There was a significant difference in the results of CVA, NDI, and DASH in FHP and healthy adults (p<0.05). Significant correlations were found between DASH and CVA in FHP participants (r = -0.656, p = 0.001). Also, in the regression analysis results of DASH and CVA, the regression model was found to be suitable and the variation in DASH could be explained by 43% (F = 15.118, p = 0.001). Conclusions: Shoulder pain and neck discomfort are potentially related, and an increase in shoulder pain can increase FHP.