• 센서학회지
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• 제30권3호
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• pp.125-130
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• 2021

In this study, the degree of alignment of polymer microfibers produced by electrospinning using a rotating water collector was evaluated. Aligned micro- and nano-fibers are required in various practical applications involving anisotropic properties. The degree of fiber alignment has many significant effects; hence, and accurate quantitative analysis of fiber alignment is necessary. Therefore, this study developed a simple and efficient method based on two-dimensional fast Fourier transform, followed by ellipse fitting. As a demonstrative example, the polymer microfibers were electrospun on the rotating water collector as the alignment of microfibers can be easily controlled. The analysis shows that the flow velocity of the liquid collector significantly affects the electrospun microfiber alignment, that is, the higher the flow velocity of the liquid collector, the greater is the degree of microfiber alignment. This method can be used for analyzing the fiber alignment in various fields such as smart sensors, fibers, composites, and textile engineering.

• Journal of Positioning, Navigation, and Timing
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• 제4권4호
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• pp.181-186
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• 2015

A High-degree Cubature Kalman Filter (CKF) is proposed to deal with the Strapdown Inertial Navigation System (SDINS) alignment problem. In-flight Alignment (IFA) is an effective method to compensate for attitude errors of the navigation system. While providing precise attitude error compensation, however, the external source aided alignment often creates a nonlinear filtering problem caused by a large misalignment angle. Introduced recently, Cubature Kalman Filter is a suitable technique for various nonlinear problems. In this paper, a higher degree CKF is applied to this accuracy-is-everything SDINS IFA problem. The simulation results show that the proposed technique outperformed a traditional nonlinear filter in terms of precision and alignment time.

• 한국경영과학회지
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• 제31권4호
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• pp.13-33
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• 2006

Using structural equation modeling, this study empirically examined the causal relationships among the level of advanced manufacturing technology (AMT), facilitation of alignment, the degree of strategic alignment of management eccounting Information systems (MAIS), and the improvement of production performance. The causal relationships between MAIS strategic alignment and information characteristics of MAIS were also investigated. The results showed that the level of AMT has a significant and positive impact on alignment facilitation. A significant causal relationship between alignment facilitation and MAIS strategic alignment was also found. It was shown that under high degrees of MAIS strategic alignment, MAIS must provide broad-scope and integrated types of Information. The causal relation-ships between MAIS strategic alignment and organizational performance were significant and positive. Thus, it is concluded that under high levels of AMT, a high degree of MAIS strategic alignment positively contributes to the improvement of production performance.

• 한국표면공학회지
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• 제42권2호
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• pp.95-101
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• 2009

This study is the research on the thermal emissivity depending on the bulk graphite's alignment degree. Bulk graphites were manufactured by uni-axial pressing and subsequent heat treatment of natural graphite flakes with organic binder. The samples were prepared to be $0^{\circ}$ (relative to the 002 c-face), $45^{\circ}$, and $90^{\circ}$ (relative to the 100 a-face) for measuring alignment degree. The alignment degree of the sample was measured by XRD. The thermal emissivity was measured by infrared thermal image camera at $100^{\circ}C$ and compared with the value obtained by Infrared spectroscopy. The alignment degree and thermal emissivity of $0^{\circ}$ sample were measured to be 0 and 0.70 respectively. And those of $90^{\circ}$ sample were 0.73 and 0.80 respectively. The emissivity value was correlated with obtained by IR spectroscopy. Therefore it was considered that the thermal emissivity of the bulk graphite is correlated with the alignment degree.

• Journal of Information Display
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• 제12권4호
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• pp.173-177
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• 2011

The alignment film abrasion caused by the rubbing process was quantitatively evaluated via atomic-force microscopy (AFM). First, a patterned alignment film structure, which was molded through the imprint method, was artificially formed. Then, the surface topography of the alignment film was evaluated via AFM after rubbing, and the degree of abrasion of the alignment film was estimated by subtracting the value after rubbing from the value before rubbing. It was recognized that the degree of abrasion increased with an increase in the rubbing strength. The relationship between the number of rubbing cycles and the degree of abrasion of the alignment film was also estimated.

• 한국재료학회지
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• 제24권3호
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• pp.159-165
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• 2014

This study is research on the thermal emissivity depending on the alignment degrees of graphite flakes. Samples were manufactured by a slurry of natural graphite flakes with organic binder and subsequent dip-coating on an aluminum substrate. The alignment degrees were controlled by applying magnetic field strength (0, 1, and 3 kG) to the coated samples. The alignment degree of the sample was measured by XRD. The thermal emissivity was measured by an infrared thermal image camera at $100^{\circ}C$. The alignment degrees were 0.04, 0.11, and 0.17 and the applied magnetic field strengths were 0, 1, and 3 kG, respectively. The thermal emissivities were 0.829, 0.837, and 0.844 and the applying magnetic field strengths were 0, 1, and 3 kG, respectively. In this study the correlation coefficient, $R^2$, between thermal emissivity and alignment degree was 0.997. Therefore, it was concluded that the thermal emissivities are correlated with the alignment degree of the graphite flakes.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.755-758
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• 2005

The mechanism responsible for liquid crystal (LC) alignment on solid substrates treated with mechanical rubbing or polarized UV is not understood. The results of x-ray reflectivity study of LC alignment on a large number of different alignment layers show that the anisotropy in the surface roughness of the substrate completely determines the LC alignment. The anchoring energy depends on the degree of roughness anisotropy and chemical interactions between the substrate and LC molecules.

• 한국콘텐츠학회논문지
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• 제22권3호
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• pp.576-585
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• 2022

월경곤란증에 대한 원인을 규명하는데 있어서 인체 대칭성과 균형에 중점을 두어 진단할 필요가 있다. 본 연구 목적은 월경곤란증 정도에 따라 자세 정렬과 족저압 균형에 차이가 있는지를 비교·분석하고자 한다. 월경곤란증을 가진 20대 여대생을 대상으로 월경곤란증 정도에 따라 경증그룹과 중증그룹으로 구분하여 자세 정렬과 족저압 균형에 대해 측정하였으며, 월경곤란증과 자세 정렬에 대한 상관관계를 분석하였다. 그 결과, 월경곤란증 정도에 따라 어깨높이 비대칭성 각도에만 유의한 차이가 나타났으며(p<0.05), 골반 및 무릎 정렬에서는 유의한 차이가 없었다. 상관관계 분석에서는 월경곤란증 점수(MDQ)와 어깨높이 비대칭성 각도 간의 유의한 양의 상관관계(r=0.621, p<0.005)가 나타났다. 이러한 결과는 월경곤란증과 어깨관절의 부정렬이 연관성이 있음을 나타내며, 이러한 요인을 분석하기 위해 후속 연구에서는 월경곤란증을 가진 여성에 대한 척추 정렬에 대해서도 알아볼 필요가 있을 것으로 생각된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2859-2872
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• 2019

Interference alignment (IA) has been a powerful approach to achieve the maximum degree of freedom (DoF) for K users multiple-input-multiple-output (MIMO) interference channels. However, due to the feasibility constraint, aligning all the interference signals at each receiver is impractical for large K without symbol extension. In this paper, we propose two best-effort interference alignment (BEIA) schemes that the network selects the maximum number of interfering transmitters to align their signals given the feasibility conditions when each transmitter-receiver pair has a constant number of data streams. Besides, in case of not all interfering signals aligned at each receiver, an upper bound of the average throughput is derived. Simulation results show that the proposed schemes have superiority over the traditional methods, such as time division multiple access (TDMA) and cluster IA(CIA), in low and moderate signal-to-noise ratio (SNR) region in terms of average user throughput. In addition, the proposed max-min relative interference distance alignment scheme outperforms the proposed scheme of equal interfering transmitters number alignment in terms of both average user throughput and minimum user throughput.

• E2M - 전기 전자와 첨단 소재
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• 제10권5호
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• pp.461-466
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• 1997

In this paper, we developed the new non-rubbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) light irradiation on polyimide (PI) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV light irradiation on PI surface. We successfully obtained that the pretilt angle of NLC is generated about 3.3 degree in the cell with slanted non-polarized UV light irradiation with 70 degree on PI surface, for the first time. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecular and the PI, which is broken the polymer by slanted non-polarized UV irradiation. Therefore, we concluded that the uniform LC alignment is attributed to anisotropic dispersion force due to photo depolymerization with slanted non-polarized UV light irradiation on PI surface.