• 한국전자파학회논문지
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• 제24권1호
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• pp.91-97
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• 2013

지표면의 후방 산란 계수를 계산하는 지표면 산란 모델의 입력 변수로는 크게 수분함유량과 지표면 거칠기가 있고, 산란 계수 계산에 있어 지표면 거칠기의 영향이 수분함유량의 영향보다 크다. 본 연구에서는 지표면 거칠기의 정확한 측정 방법을 제기하고, 측정 오차를 분석한다. 이를 위하여 대표적인 지표면 거칠기 측정 장치인 pin-board profiler(1 m, 0.5 cm 간격)와 laser profiler(1 m, 0.25 cm 간격)를 이용하여 실제 지표면을 측정하였다. 두 측정 장치의 평균 차이는 유효 높이(RMS height)가 0.097 cm, 상관 길이(correlation length)가 1.828 cm이었다. 그리고 상관 함수, 상대오차를 분석한 결과, laser-profiler의 반복 측정에 대한 장치의 안전성이 더 좋았다. 두 측정 장치의 차이가 후방 산란 계수에 미치는 영향을 분석하기 위해 지표면 산란 모델을 이용하여 비교한 결과, 입사각 $20{\sim}60^{\circ}$에서 1 dB 이하의 차이를 보였다.

• 한국수학교육학회지시리즈A:수학교육
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• 제62권4호
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• pp.457-471
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• 2023

측정은 초등 수학의 핵심 영역이지만 중요도에 비하여 측정 상황에서 단위에 대한 학생들의 이해는 충분하지 않은 것으로 보고되고 있다. 이에 본 연구는 길이 측정 상황에서 초등학교 저학년 학생의 단위 추론에 대한 수준을 분석하여 이를 바탕으로 측정 영역에서 단위 추론을 지도하기 위한 방안을 모색하고자 하였다. 이를 위하여 개방형 수직선을 활용하여 길이 측정 과제를 적용한 초등학교 2학년 학생들의 응답을 수집 및 분석하였다. 연구 결과, 초등학교 저학년 학생들의 단위 추론 수준은 단위화, 단위 반복, 단위 분할 정도에 따라 1단위 반복하기, 주어진 단위 반복하기, 단위 사이의 관계 알기, 단위 변환하기의 4개의 수준으로 나타났다. 가장 많은 분포를 보인 수준은 길이 측정을 위해 단위 사이의 관계를 인식하는 수준이었으며 각 수준을 대표하는 단위 추론에 대한 학생들의 수준별 특징과 사례를 제시하였다. 본 연구 결과를 토대로 초등학교 저학년 학생들의 단위 추론 수준에 맞는 지도 방안이 요구되며, 불완전한 단위 추론 능력을 가진 친구들을 위한 추가 지도나 맞춤형 중재물의 활용이 필요함을 논의하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.1073-1077
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• 1996

This paper presents a recoil and counter recoil(R&CR) motion measurement method using linear variable differential transformers(LVDT). The output of a LVDT is obtained from the differential voltage of the 2nd transformers. As a sensor core is attached at the motion body, the output is directly proportional to the core motion. Displacement, velocity and acceleration are measure from the core length. With a comparison between the measurement result and the known value which is obtained by the precision steel tape, the accuracy and the usefulness of the proposed scheme is validated.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.556-565
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• 2003

Light losses in optical fibers are investigated by a fiber optic OTDR (Optical Time Domain Reflectometry) sensor system to develop fiber optic probes for structural displacement measurement. The displacement sensitivity was determined by the measurements of fiber-bending loss according to the gage length changes of the displacement sensor. The fiber optic displacement probe was manufactured to verify the feasibility of the structural displacement measurement.

• 한국생활과학회지
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• 제11권1호
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• pp.45-58
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• 2002

The purpose of this study was to offer a more functional slacks by analyzing its crotch length. The result of the study were as follows : Regarding the feeling of wearing and appearance, the P2 b style which measures the crotch length starting from the waist line passing around the iliac spine was the most highly evaluated. This suggested that the functionality of dance movement was more influenced by the position of the waist line not by the crotch length measurement. Since the front and rear center lines of the crotch could not be flown if the waist line of slacks was positioned high, both the crotch and abdominal part might be clogged or tightened when dancers made large dance movements or bended their upper bodies forward. In conclusion, slacks for more functional dance movement should be manufactured focusing on the location of the waist line rather than on the crotch length.

• 대한기계학회논문집A
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• 제33권12호
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• pp.1375-1382
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• 2009

The objective of this paper is to apply the load ratio method to the measurement of the crack length of the real scale pipe specimen. The load ratio method was modified and finite element analyses were performed to derive the relationship between the normalized compliance and the normalized crack length for the pipe specimen. In order to measure the crack length, the direct current potential drop method and the modified load ratio method were applied to the pipe test. The applicability of the modified load ratio method was confirmed by comparing the calculated crack length with the measured crack length from the pipe experiment.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1996년도 춘계학술대회논문집
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• pp.218-223
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• 1996

The foot shape from the right and left feet was taken with 78 male and 213 female Korean subjects. The results are as follows. 1) Mean values and standard deviations of 25items concering the foot : Measurements performed on Korean adults(male and female) show that male left foot length is in average somewhat longer than the corresponding right foot length(25.35Cm against 25.32Cm) and on the contrary that the circumference of the left foot is slightly smaller than for the right foot. For the same tendency is verified in female feet. 2) Correlations between measurement items : Finding a correlation of more than 0.08 only between the foot length to suggest that the present system of ready-made "shoe" size system, based only on foot length, is not a quite appropriate system. 3) Distribution between foot width, foot girth, instep height and foot length : Foot length showed from 21.52Cm to 24.0Cm in the female subjects and from 24.0Cm to 26.5Cm in the male subjects for the standard type. Foot width showed from 7.5Cm to 10.0Cm in female and from 8.5Cm to 10.5Cm in male for the standard type.dard type.

• 제어로봇시스템학회논문지
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• 제10권6호
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• pp.494-500
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• 2004

This paper presents a machine vision system, which inspects the measurement of the ALC block on a real-time basis in the production process. The automatic measurement system was established with a CCD camera, an image grabber, and a personal computer without using assembled measurement equipment. Images obtained by this system was processed by an algorithm, specially designed for an enhanced measurement accuracy. For the realization of the proposed algorithm, a preprocessing method that can be applied to overcome uneven lighting environment, boundary decision method, unit length decision method in uneven condition with rocking objects, and a projection of region using pixel summation are developed. From our experimental results, we could find that the required measurement accuracy specification is sufficiently satisfied by using the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1211-1215
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• 2005

In the GPS attitude determination system, the baseline length constraints can be used efficiently to reduce the search space. It is possible by adopting the assumptions that the baseline length doesn't change and the true baseline length is precisely known. But in real situation, the baseline length might be changed by many reasons and it is impossible to measure the true baseline length because there exists measurement error and antenna phase centre movement. In order to analyze the effect of the baseline length accuracy, one needs to know the relation between the accuracy of the baseline length and success rates of the integer ambiguity resolution. In this paper, the effect of the baseline length accuracy to the integer ambiguity resolution in the attitude determination system is analyzed by empirical method. The results show that the margins in the baseline length accuracy is less than a few cm which implies that one should take great cares when applying the attitude determination system to the flexible structures.

• 한국정밀공학회지
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• 제30권4호
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• pp.450-458
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• 2013

The aim of this study was to develop and verify gait training system for post-stroke hemiplegia patients with step length asymmetry. Most post-stroke hemiplegic patients show gait asymmetry and weight shifting training has been suggested as a useful method for improving the walking ability. However, verbal cue by physical therapist may be not effective. Therefore, our weight shift training system was designed to give a feedback to patients through precise plantar pressure and center of pressure (COP) measurement. This weight shifting biofeedback training system is composed of F-Scan plantar pressure measurement system and software development kit (SDK) for Windows operating system. Two post-stroke patients with step length asymmetry were enrolled in this study. After training for six weeks, the weight shift score and step length ratio of two all patients were improved and approached to them of non-disabled. This system developed in this study may improve the step length asymmetry, and therefore this system is also expected to improve a walking ability in hemiplegic patients.