• 한국수산과학회지
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• 제35권4호
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• pp.451-453
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• 2002

The rotation of the flagellar motor is powered by the electrochemical gradient of specific ions across the cytoplasmic membrane. Recently, the gents of the Na'-driven motor have been cloned from marine bacterium of Vibrio sp. and some of the motor proteins have been purified and characterized. Also, motx gene encoding a channel component of the sodium type flagellar motor was identified from Vibrio Huuiaiis (KTCC 2473). The amino acid sequence of MotX protein from V, Huvialis shared 90, 85, $85\%$ identity with V, cholerae, V. alginolyticus, V parahaemolyticus, respectively. We have studied the localization of the expressed MotX protein in Escherichia coli by immune-gold labeling of ultra-thin frozen section. Our observation of the expressed protein indicated that MotX protein could be existed as attachment to inner membrane in E. coli.

• 한국정보통신학회논문지
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• 제18권7호
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• pp.1525-1530
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• 2014

본 논문은 산업용 로봇을 위한 힘 피드백 제어 기반의 연마면의 보정과 작업자의 감각을 기반으로 한 정확한 연마면 작업을 대체하기 위한 교시방법을 적용한 연마 결과를 제시하였다. 교시방법은 연마작업의 위치, 경로, 반응에 대한 정밀도 개선을 위해서 연마로봇에 적용하였다. 힘 센서 기반의 교시방법에 의해 연마가 가능한 선박용 연마로봇을 제시하였고, 힘 센서에 의한 교시방법을 연마로봇에 적용하여 실험한 결과를 제시함으로써 그 유효성을 검증하였다. 또한, 로봇교시 포인터의 수를 줄이기 위하여 가공면의 특이점들만을 이용하여 곡면 가공이 가능하도록 로봇 궤적을 생성하는 방안을 제시하여 실험결과를 제시하였다.

• 한국기계가공학회지
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• 제12권6호
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• pp.45-51
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• 2013

Friction stir welding using aluminum alloys has been widely applied for transportation vehicles because of the light specific weight, which can be used to obtain sound joint and high mechanical properties. This study shows the effects of rotation speed, welding speed, welding load, and tool shape on defect formation with extruded AA6005, which is used for railway vehicle structures of non-uniform thickness welded by friction stir welding using load control systems. Optical microscopy observations and liquid penetrant testing of each FSW joint were carried out in order to observe defect formation. Two kinds of defects, that of probe wear and that of lack of penetration in the bottom of the welded zone, were observed. In the case of using a taper shaped tool, the defect free zone is very narrow, within 100 kgf; however, in case of using a cylindrical shape tool, the defect free zone is wider.

• 대한화학회지
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• 제57권5호
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• pp.533-539
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• 2013

변전위법과 전기화학 임피던스 측정법을 이용하여 borate 완충용액에서 니켈 회전원판전극의 전기화학적 부식과 부동화를 연구하였다. Tafel 기울기, 임피던스, 회전원판전극의 회전속도, 그리고 부식전위와 부식전류의 pH 의존성으로부터 니켈의 부식과 부동화 반응 메커니즘과 환원반응에서의 수소 발생 반응구조를 제안하였다. EIS data로부터 등가회로를 제안하였으며 산화반응의 영역별로 전기화학적 변수들을 측정하였다. 부동화 반응에 의하여 생성된 $Ni(OH)_2$ 산화피막은 전기장의 영향을 받는 탈수반응에 의해 NiO로 전환되는 것으로 보인다.

• 한국산업정보학회논문지
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• 제4권2호
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• pp.1-6
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• 1999

화상 데이터의 특성을 표현하는데 적합한 깁스분포를 바탕으로 특징벡터를 추출하여 패턴을 분류하는 새로운 알고리즘을 제안하였다. 특징벡터는 화상의 크기, 위치, 회전에 대해서 불변이며 접영에 대해서도 덜 민감한 특징을 갖는 2차원 모멘트들의 원소로 만들어진다. 알고리즘은 공간정보를 갖는 2차원 모멘트를 이용하여 특징벡터를 추출하는 과정과 거리함수를 이용하여 패턴을 분류하는 과정으로 구축하였다. 특징벡터는 깁스분포의 묘수를 추정하여 2차원 조건부 모멘트를 추출하여 구성한다. 패턴 분류 과정은 추출된 특징벡터로부터 제안된 판별거리함수를 계산하여 여러 원형 패턴 가운데 최소거리를 산출한 미지의 패턴을 원형패턴으로 분류한다. 제안된 방법의 성능을 검증하기 위하여 대문자와 소문자 52자로 구성된 훈련 데이터를 만들어 SUN ULTRA 10 워크스테이션에서 실험을 한 결과 98%이상의 분류성능이 있음을 밝혔다.

• 한국의료질향상학회지
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• 제26권1호
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• pp.2-10
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• 2020

Purpose: This study aimed to determine the effect of curved walking training on balance confidence and fall efficacy in early stroke patients. Methods: The study included 16 early stroke patients who were randomly allocated to a curved walking training group (experimental group, N=8) and a straight walking training group (control group, N=8). Both groups performed the exercise 5 times a week for 3 weeks. Outcomes were assessed using the Activities-specific Balance Confidence (ABC) Scale, Fall Efficacy Scale (FES), Berg Balance Scale (BBS), and Timed Up and Go (TUG) test. Results: After 3 weeks of training, both groups showed significantly improved ABC, FES, BBS, and TUG (p<.05 in both groups). However, the ABC, FES, BBS, and TUG scores in the experimental group were significantly better than those in the control group (p<.05). Conclusion: These findings indicate that curved walking training may be effective at improving balance confidence and decreasing fall risk in early stroke patients. Therefore, curved walking training can be used as a recommended walking method in early stroke patients.

• 전기학회논문지
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• 제67권6호
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• pp.782-788
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• 2018

This paper proposes a novel method for the omnidirectional camera-based image rendering synchronization system using head mounted display. There are two main processes in the proposed system. The first one is rendering 360-degree images which are remotely photographed to head mounted display. This method is based on transmission control protocol/internet protocol(TCP/IP), and the sequential images are rapidly captured and transmitted to the server using TCP/IP protocol with the byte array data format. Then, the server collects the byte array data, and make them into images. Finally, the observer can see them while wearing head mounted display. The second process is displaying the specific region by detecting the user's head rotation. After extracting the user's head Euler angles from head mounted display's inertial measurement units sensor, the proposed system display the region based on these angles. In the experimental results, rendering the original image at the same resolution in a given network environment causes loss of frame rate, and rendering at the same frame rate results in loss of resolution. Therefore, it is necessary to select optimal parameters considering environmental requirements.

• 한국소음진동공학회논문집
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• 제12권12호
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• pp.921-928
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• 2002

Main sources of the nitration of a gear-pair system are backlash and transmission error, the difference between required and actual rotation during gear meshing. This paper presents the nonlinear dynamic characteristics of gear motions due to the existence of backlash and periodic variation of meshing stiffness, which is assumed as a one-term harmonic component. Gear motions are classified as three types with the consideration of backlash. Each response is calculated using the harmonic balance method and confirmed by numerical integration. The responses with the increase of the rotating speed show abrupt changes in its magnitude for the variation of the preload, exciting force, and damping coefficient. The result also shows that there is a chaotic motion with some specific design parameters and operating conditions In gear diving system. Consequently the design of gear driving system with low nitration and noise requires the study on the effects of nonlinear dynamic characteristics due to stiffness variation and backlash.

• Computers and Concrete
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• 제16권2호
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• pp.191-207
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• 2015

It is generally accepted that, in the interest of safety, it is essential to provide a minimum level of flexural ductility, which will allow energy dissipation and moment redistribution as required. If one wishes to be uniformly conservative across all of the design variables, curvature ductility and moment redistribution factor should be calculated using a probabilistic method, as is the case for other design parameters in reinforced concrete mechanics. In this study, simple expressions are derived for the evaluation of curvature ductility and moment redistribution factor, based on the concept of demand and capacity rotation. Probabilistic models are then derived for both the curvature ductility and the moment redistribution factor, by means of central limit theorem and through taking advantage of the specific behaviour of moment redistribution factor as a function of curvature ductility and plastic hinge length. The Monte Carlo Simulation (MCS) method is used to check and verify the results of the proposed method. Although some minor simplifications are made in the proposed method, there is a very good agreement between the MCS and the proposed method. The proposed method could be used in any future probabilistic evaluation of curvature ductility and moment redistribution factors.

• Macromolecular Research
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• 제17권11호
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• pp.912-918
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• 2009

An optically active diacid containing the L-histidine moiety was prepared by reacting pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydride) 1 with L-histidine 2 in acetic acid, and was polymerized with several aromatic diamines 5a-g to obtain a new series of optically active poly(amide-imide)s (PAIs) using two different methods, such as direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$)/pyridine (Py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (Py)/N,N-dimethylformamide (DMF) system as a condensation agent. The resulting new polymers 6a-g with inherent viscosity was obtained in good yield. The polymers were readily soluble in polar organic solvents, such as N,N-dimethyacetamide (DMAc), N,N-dimethyformamide (DMF), and dimethyl sulfoxide (DMSO). The obtained polymers were characterized by FTIR, specific rotation, elemental analysis as well as $^1$H-NMR spectroscopy and gel permeation chromatography (GPC). The thermal stability of the resulting PAIs was evaluated with thermogravimetric analysis techniques under a nitrogen atmosphere.