• 응용통계연구
• /
• 제8권2호
• /
• pp.65-75
• /
• 1995

설명변수 축소방법들인 Sliced Inverse Regression과 Principal Hessian Directions에서는 효과적 차원축소공간의 차원을 결정하기 위하여 설명변수의 정규성과 충분한 수의 자료가 요구되는 점근적검정(asymptotic test)을 제시하고 있다. 본 연구에서는 Cook과 Weisberg(1991)가 제안하였던 순열검정통계량(permutation test statistic)을 개발하여 SIR과 PHD에서 제시된 점근적 검정 통계량과 검정력을 비교하기로 한다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
• /
• pp.704-707
• /
• 2004

The structure should be designed to be safe to any direction of earthquake input. However, the reference axes whereby the structure is analyzed and designed against earthquake may influence the design member forces. This study is concerned with the effect of the choice of the reference axes on the seismic design member forces. The analytical results on member forces using the principal axes suggested by Wilson and the global axes generally adopted in design offices show that the values of member forces by the principal axes be about $15\%$ smaller than those by the global axes in the example structure.

• 한국농공학회지
• /
• 제41권2호
• /
• pp.70-79
• /
• 1999

The lower ground of structure, in which the strip loads, such as earth dams and embankments , are signiificantly working on , is required to be interpreted as a state of plane strain where the strain of intermediated principal stress direction is put '0' . The plane strain state is frquently observed in actural soil engineering case. For those case, drained stress-strain and strength behavior of Iksan weathered granite soil prepared in cubical specimens with cross-anisotropic fabric was studied by conventional triaxial compression, plane strain and cubial triaxial tests with independent control of the three principal stress. All specimens were loaded under conditions of principl stress directions fixed and aligned with the directions of the material axes. As a result of research , when a ground condition is analyzed under plane strain state, the shear strength obtained from the conventional triaxial compression test can be understimated.

• 한국운동역학회지
• /
• 제20권2호
• /
• pp.117-127
• /
• 2010

The axes of upper forearm coordinate system have been considered as principal axis of each segment which was component of elbow joint. The purpose of this study was to verify whether the mean direction(principal axis) of instantaneous axes of rotation for pure flexion/extension motion coincided with the flexion/extension axis of upper forearm coordinate system. The same procedure was done for pronation/supination motion. Furthermore, it was tested indirectly that there was an interaction effect between the two rotational motions. The results showed that most segment coordinate axes statistically were not consistent with the mean directions of flexion/extension and pronation/supination axes of rotation. From the results, it would be concluded that the ISB coordinate systems was proved to be a little valid for human movement analysis. There also was an effect of pronation/supination angles on flexion/extension motion.

• Elastomers and Composites
• /
• 제57권4호
• /
• pp.205-214
• /
• 2022

Research on reducing the thickness of polyethylene terephthalate (PET) bottles is necessary to reduce the amount of plastic used. However, as decreasing a PET bottle's thickness weakens it, a robust bottle design is required. Therefore, in this study, we numerically analyzed various bottom designs of a carbonated soft drink PET bottle with 245 and 500 ml capacities and complicated petaloid shapes. Deformation, equivalent stress, maximum principal stress, and its direction according to each design were analyzed to study the strength of the bottle. The results serve as a reference to design robust petaloid PET bottle bottoms with a reduced thickness for carbonated soft drinks.

• KCI Concrete Journal
• /
• 제12권2호
• /
• pp.55-72
• /
• 2000

This paper proposes a mechanical model to describe the load-deformation responses of the reinforced concrete plate members under service load state. An Analytical method is introduced on the basis of the rotating crack model which considers equilibrium, compatibility conditions, load-strain relationship of cracked member, and constitutive law for materials. The tension stiffening effect in reinforced concrete structures is taken into account by the average tensile stress-strain relationship from the load-strain relationship for the cracked member and the constitutive law for material. The strain compatibility is used to find out the crack direction because the crack direction is an unknown variable in the equilibrium and compatibility conditions. The proposed theory is verified by the numerous experimental data such as the crack direction, moment-steel strain relationship, moment-crack width relationship. The present paper can provide some basis for the provision of the definition of serviceability for plate structures of which reinforcements are deviated from the principal stresses, because the present code defines the serviceability by the deflection, crack control, vibration and fatigue basically for the skeletal members. The proposed theory is applicable to predict the service load state behavior of a variety of reinforced concrete plate structures such as skew slab bridges, the deck of skew girder bridges.

• 대한원격탐사학회지
• /
• 제10권2호
• /
• pp.49-62
• /
• 1994

Look direction bias in a single look SAR image can often be misinterpreted in the geological application of radar data. This paper investigates digital processing techniques for SAR image data integration and compensation of the SAR data look direction bias. The two important approaches for reducing look direction bias and integration of multiple SAR data sets are (1) principal component analysis (PCA), and (2) wavelet transform(WT) integration techniques. These two methods were investigated and tested with the ERS-1 (VV-polarization) and CCRS*s airborne (HH-polarization) C-SAR image data sets recorded over the Sudbury test site, Canada. The PCA technique has been very effective for integration of more than two layers of digital image data. When there only two sets of SAR data are available, the PCA thchnique requires at least one more set of auxiliary data for proper rendition of the fine surface features. The WT processing approach of SAR data integration utilizes the property which decomposes images into approximated image ( low frequencies) characterizing the spatially large and relatively distinct structures, and detailed image (high frequencies) in which the information on detailed fine structures are preserved. The test results with the ERS-1and CCRS*s C-SAR data indicate that the new WT approach is more efficient and robust in enhancibng the fine details of the multiple SAR images than the PCA approach.

• Composites Research
• /
• 제18권1호
• /
• pp.38-44
• /
• 2005

본 연구에서는 단일방향 탄소섬유강화복합재료 판에서 $S_o$ 대칭모드의 군속도 분선곡선을 전파 방향을 변화시키먼서 계산하였다. 그리고 속노 분산 곡선에서 첫 번째 단절주파수 이하인 0.2 MHz-mm에 해당하는 $S_o$ 대칭모드 군속도를 가지고서 위상속도 곡선을 얻고 slowness 곡선을 도입하여 군속도 곡선으로 교정하였다. 단일방향 섬유강화복합재료 판에서 $S_o$ 대칭모드의 속도를 전파 방향을 변화시키면서 측정하였고 교정된 군속도 곡선과 비교하였다. 측정된 속도는 섬유 방향 근처의 cusp 영역을 제외하고는 교정된 군속도 곡선과 잘 일치하였다. 이것은 단일방향 탄소섬유강화복합재료 판에서 속도가 빠른 방향으로 에너지를 더 잘 전파하기 때문에 전파 방향이 주축방향과 일치하지 않을 때 군속도 방향은 섬유 방향 쪽으로 기울어지는 결과로 나타난 것이다.

• 대한화학회지
• /
• 제27권4호
• /
• pp.244-254
• /
• 1983

최적 조건에서 티오황산나트륨$(Na_2S_2O_3) 포와 수용액으로부터 단결정을 생성시킨다. 이 단결정에 약 $20{\times}10^6$ 렌트겐의 ${\gamma}$-선을 조사시키면 그 결정 내부에 상자성 중심 또는 상자성 결함들이 생성되어 진다. g값이 2.0036인 등방성 D.P.P.H 피크를 기준으로 하여 무등방성인 각 상자성종들의 스펙트럼을 상온에서 X-band 전자 스핀 공명 분석기로 얻었다. 무등방성 피이크들의 각도의존성을 나타내기 위하여 서로 직교하는 a, b, c 결정축으로 $0^{\circ}$에서 $180^{\circ}$까지 $10^{\circ}$간격으로 회전시키면서 ESR 스펙트럼을 기록하였다. 무등방성 피이크들과 등방성 D.P.P.H 피이크간의 선위치 거리로부터 g값들을 계산하고 각 상자성종들의 g값의 9 matrix 원소들을 얻어 대각화(diagonalization)시켜 특성 주 g 값(principal g values)과 방향여현(direction cosine)을 얻었다. 이 특성 주 g값과 방향여현으로 ${\gamma}$-선에 조사된 $Na_2S_2O_3$ 단결정내의 상자성 결함을 분석한 결과 이 단결정내에 무등방성 피이크에 해당하는 $SO_2^+, SO_2^- $및 미확인된 불안정한 상자성 중심 등이 존재함을 확인하였다.

• 한국지구과학회지
• /
• 제29권3호
• /
• pp.255-262
• /
• 2008

고흥지역 일대에 분포하는 백악기 화강암을 대상으로 석영내에 발달해 있는 아문미세균열을 측정하여 연구지역의 고응력장을 분석하였다. 5개의 시료(GH-1, GH-3, GH-4, GH-5, GH-8)에서 아문미세균열들의 방향을 측정하여 분석한 결과, GH-1, GH-3, GH-4에서 최대수평주응력은 $N60^{\circ}W$와 $N70^{\circ}E$, $N20^{\circ}W,\;N50^{\circ}W$의 방향성이 가장 우세하였으며, N-S와 $N30^{\circ}E$의 방향성도 미약하게 나타났다. GH-5와 GH-8시료에서는 최대수평주응력의 방향 $N40^{\circ}E$와 $N10^{\circ}E$가 가장 우세하였고, $N40^{\circ}W$의 방향성도 미약하게 나타났다 전체적인 최대수평주응력의 방향은 $N60^{\circ}W$가 가장 우세하였으며, $N20^{\circ}W$, $N20^{\circ}E$, $N70^{\circ}E$등의 방향성도 미약하게 나타났다. 이 연구의 결과와 기존의 고등력장에 관한 연구결과를 종합해 볼 때, 백악기 말에서 신생대 3기 초 사이 연구지역에 작용한 최대수평주응력의 방향은 WNW에서 NE로 변화했을 것으로 판단되며, 그 원인으로는 그 당시 동북아시아 일대에 일어났던 복잡한 지구조운동에 기인한 것으로 사료된다.