• Transactions on Electrical and Electronic Materials
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• 제5권1호
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• pp.15-18
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• 2004

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a-C:H thin film by plasma enhanced chemical vapor deposition (PECVD) system for 30 sec under 30W rf power at a gas pressure of 1.4＊10$\^$-1/ torr. A high pretilt angle of about 5 by ion beam exposure on the a-C:H thin film surface was measured. A good LC alignment by the ion beam alignment method on the a-C:H thin film surface was observed at annealing temperature of 250$^{\circ}C$, and the alignment defect of NLC was observed above annealing temperature of 300$^{\circ}C$. Consequently, the high LC pretilt angle and the good thermal stability of LC alignment by the ion beam alignment method on the a-C:H thin film by PECVD method as working gas at 30W rf bias condition can be achieved.

• 한국군사과학기술학회지
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• 제6권1호
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• pp.21-29
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• 2003

The Strap Down Inertial Measurement Unit(SDIMU) is recently used for the sensor package of the modern underwater vehicles such as torpedoes and unmanned underwater-vehicles. For using SDIMU, an initial alignment must be carried out before the fire or navigation stage. The general initial alignment methods require that a mother vehicle Is a stationary condition or the Inertial Navigation System(INS) of vehicle is received the specific of data navigation from the mother vehicle. But an underwater vehicle dropped from aircraft is hard to satisfy above both necessary conditions of the general initial alignment. So, we suggest a new strap down initial alignment method of an underwater vehicle dropped from aircraft without using any aided sensors. The highlight point of this method is that a period of initial alignment is not before the fire but during running stage to fix alignment error. And we verify it by analyzing various data of S/W simulations, Hardware In the Loop Simulation(HILS) tests and sea trials.

• 한국운동역학회지
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• 제28권2호
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• pp.119-125
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• 2018

Objective: The purpose of this study was to compare the effect of different 12-week exercise programs for posture correction on postural alignment in elderly women. Method: The study included 36 elderly women who were randomly divided into 3 groups: Group A (core exercise, n=12), Group B (combined exercise, n=12), and Group C (Pilates exercise, n=12). Postural alignment was measured using 6 variables in frontal and sagittal planes. Two-way mixed analysis of variance was used to compare the effect of exercise program types on postural alignment and a paired t-test was used to compare differences in postural alignment after exercise. Results: The core exercise group showed statistically significant improvement (p<.05) in multiple upper and lower body postural alignment measurements. The combined exercise and Pilates exercise groups showed statistically significant improvement (p<.05) in upper body measurements alone. Conclusion: Core exercise, combined exercise, and Pilates exercise improved postural alignment in elderly woman through improvement in muscle strength and ligament flexibility around the spine and pelvis.

• 국제물리치료학회지
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• 제11권4호
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• pp.2184-2190
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• 2020

Background: Although studies have been conducted on muscle thickness and balance in trunk stabilization exercise and exercise using vibration props, studies on trunk stabilization exercise using active vibration for spinal alignment are still insufficient to draw a conclusion. Objectives: To investigate the effect of trunk stabilization exercise using active vibration on the spinal alignment in adult females. Design: A randomized controlled trial. Methods: Twenty-six adult females were randomly assigned to the experimental group (active vibration) and 13 control groups (active non-vibrating) and exercised three times a week for 8 weeks. Each group was measured for spinal alignment before exercise and 8 weeks after exercise. Spinal alignment, trunk imbalance, pelvic tilt, and pelvic torsion were measured using a spinal alignment analyzer. Results: Trunk imbalance was a significantly different depending on the time in the experimental group and the control group (P<.05). Pelvic tilt was a significant difference between the groups (P<.05). Also, pelvic tilt was a significantly different depending on the time in the experimental group (P<.05), but the control group showed no significant difference (P>.05). Pelvic torsion was no significant difference in both groups (P>.05). Conclusion: This study demonstrates that trunk stabilization exercise using active vibration has a positive effect on the alignment of the spine.

• 한국항공우주학회지
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• 제48권12호
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• pp.987-995
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• 2020

고성능 탑재체들과 자세제어 센서들 간의 정밀정렬은 인공위성의 정확한 자세지향 및 높은 지향 안정성을 위해 필수적이다. 위성 개발사들은 조립 및 시험기간 동안 위성 정렬을 위해 데오드라이트 측정 시스템을 주로 사용한다. 데오드라이트 측정 시 시선 방향 오차, 수평축의 오차, 수직방향 인덱스 오차 그리고 수직축 오차로 인해 측정오차가 발생할 수 있다. 이러한 오차들 뿐 아니라 다수의 데오드라이트를 사용한 측정 시 발생할 수 있는 오차들을 정렬큐브 측정실험을 통해 분석하였다. 정렬큐브 측정실험을 기반으로 정렬측정 정확도를 향상시킬 수 있는 방법이 제안되었고, 측정 결과 위성의 설계 요구조건도 만족시킬 수 있었다.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3703-3716
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• 2022

Target alignment technology is one of the most critical technologies in laser fusion experiments and is an important technology related to the success of laser fusion experiments. In this study, by combining the open-loop and closed-loop errors of the target alignment, the Kalman state observer is used to estimate the position of the target, which improves the observation precision of the target alignment. Then the optimized result is used to guide the alignment of the target. This method can greatly optimize the target alignment error and reduce uncertainty. With the improvement of the target alignment precision, it will greatly improve the reliability and repeatability of the experiments' results, thereby improving the success rate of the experiments.

• 한국항행학회논문지
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• 제26권4호
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• pp.195-204
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• 2022

본 논문에서는 경사 고각 발사 시스템에서 활용하기 위한 발사체 항법장치의 급속 초기정렬기법에 대해 다룬다. 급속초기정렬기법 중 하나인 원샷(One-shot) 정렬기법은 발사대에 장착된 항법장치의 정보를 활용하므로 수 초 내에 정렬이 가능하지만, 수직 발사체계에서만 적용되어 경사 고각에서의 성능이 검증되지 않았다. 따라서 본 논문에서는 원샷 정렬기법을 경사 고각 발사 시스템으로 적용 시 발생하는 오차 요소에 대해 분석하였고, 이를 최소화하여 정렬 성능을 개선하기 위한 방안을 소개하였다. 추가로, 제시한 원샷 정렬기법에 대해 성능시험을 수행함으로써, 실 항법장치를 운용하는 환경에서도 유효한 효과가 있음을 확인하였다.

• 폴리머
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• 제27권5호
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• pp.484-492
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• 2003

러빙에 의해 유도된 네마틱 액정의 배향 특성과 그 안정성이 액정-폴리이미드 계면 특성과 어떠한 관계가 있는지를 조사하였다. 합성된 5 종류의 폴리이미드 특성을 분석하고 폴리이미드 배향막에서의 액정 배향의 균일성, 선경사각, 정착 에너지, 그리고 열 안정성을 측정 조사하였다. 러빙된 폴리이미드는 강한 정착의 액정 배향을 유도하고 액정 배향의 특성과 안정성은 배향막 표면에서의 액정과 폴리이미드 간의 분자 차원의 상호작용에 의해 결정된다는 것을 확인하였다. 폴리이미드의 유연성의 증가는 이미드화를 촉진시키며 액정의 선경사각과 배향 안정성을 증대시킨다. 반면에, 폴리이미드의 플루오르화는 액정의 배향성 및 배향 안정성을 감소시키는 것으로 나타났다. 폴리이미드의 방향족과 지방족 고리 이무수물 구조에 따른 액정 배향의 특성과 안정성에는 뚜렷한 차이가 나타나지 않았다.

• 대한통합의학회지
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• 제6권2호
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• pp.99-106
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• 2018

Purpose : Various studies effects of mental practice. However, there is a lack of research on the effects of practice on postural alignment. Therefore this study to the effect of ankle exercise combined with mental practice on postural alignment of legs. Method : Subjects were randomly assigned to mental practice group (experimental group n=15) and general exercise group (control group n=15). Postural alignment was the hip, knee, and ankle joints. When viewed from the side, an arbitrary point in front of the malleolus makes a straight line with the plumb line. Exercise was performed a week for weeks. Exercise programs included muscle strengthening, relaxation, and proprioception exercise. The experimental group mental practice. Result : Both groups showed significant differences in postural alignment ankle joint, knee joint, and hip joint. In particular, the experimental group showed a larger change than the control group. However, significant difference in postural alignment change only the knee joint (p<0.05), and there was no significant difference the hip joint (experimental group=$0.77{\pm}0.81$, control group=$0.87{\pm}1.13$) and ankle joint (experimental group=$0.52{\pm}0.63$, control group=$0.48{\pm}0.41$). Conclusion : This study suggests that mental practice is effective as an exercise method postural alignment. Mental practice also expected to be musculoskeletal disorders. Therefore, additional studies should be conducted to verify the effect of mental practice on the alignment of various parts.

• 대한토목학회논문집
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• 제43권5호
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• pp.651-657
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• 2023

국내외 철도사업에서 철도의 신규 건설과 더불어 기존선의 개량을 통한 증속, 고속화 사업도 큰 비중을 차지고 있다. 특히 해외의 개발도상국은 경제수준을 고려할 때 고속철도의 건설은 막대한 규모의 예산소요와 수요를 고려할 때 한계가 있어, 기존 철도의 선형개량을 통한 증속사업이 실현가능성이 높은 것으로 판단하고 있다. 본 연구에서는 선형개량을 통향 기존선의 증속사업의 효율적 기획과 분석을 위하여, 기존에 신규 철도 건설사업 분석에 활용되고 있는 지능형 철도선형계획 프로그램(ei-Rail)에 선형개량사업 분석 기능을 추가할 수 있는 방법론을 개발하였다. 수치지도 또는 기존의 위성사진 자료를 기반의 베이스 맵에 기존의 철도선형을 입력하고, 목표속도등 선형개량사업의 목표를 입력하면, 사업의 비용과 도면, 증속효과 분석 결과 등을 자동적으로 제시함으로써, 철도선형개량 사업의 기획과 분석을 효율적으로 수행할 수 있는 도구로 활용될 수 있도록 하였다.