• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.466-469
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• 1995

This paper presents a design and performance of the 6 D.O.F linear motion table with a magnetic bearing suspension. The linear positioning of the table with a 150mm stroke is driven by a brushless DC Linear motor and the other attitudes of the stage are controlled by the analog PD controller with magnetic bearing actuators. Each magnetic bearing unit which consists of 3 electromagnets, 3 capacitance probes and 3 backup bearings affords controlled forces by detecting the air gap between the probes and guideways. An integral type capacitance probe amplifier is equipped on the upper plate of the table so that the probe line to the probe amplifier can be shorter therefore the problems due to the stray capacitance and noise can be reduced. Form the pitch-yaw errormeasured by the autocollimator, the vertical and horizont straightness errors of the table are derived that they are maintained below 1.mu. m over 100mm stroke. The positioning accuracy of the linear motion is maintained below 2 .mu. m and the repeatability error is below 1 .mu. m

• 한국전문물리치료학회지
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• 제21권1호
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• pp.1-12
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• 2014

The purpose of this study were to determine the intra-rater and inter-rater reliability of shoulder passive range of motion measurement using the "Clinometer + bubble level", a smartphone application and to compare with the intra-rater and inter-rater reliability of measurement using a goniometer. Twenty six patients with stroke were recruited for this study. Two raters measured the passive range of motion of four types of shoulder movements (forward flexion; FF, abduction; ABD, external rotation at $90^{\circ}$ abduction; ER90 and internal rotation at $90^{\circ}$ abduction; IR90) using a goniometer and a smartphone to determine within-day inter-rater reliability. A retest session was performed thirty minutes later to determine within-day intra-rater reliability. The reliability was assessed using intraclass correlation coefficients (ICC) and the standard error of measurement (SEM). The ICC (2,1) for the inter-rater reliabilities of the goniometer and smartphone were good in FF and ABD [ICC (2,1)=.75~.87] and excellent in ER90 [ICC (2,1)=.90~.95]. The intra-rater reliabilities for the goniometer and smartphone were good or more than good, with an ICC (3,1) value >.75, the exception was IR90 measured by rater 2 on the smartphone. These results suggest that smartphone could be used as an alternative method tool for measurement of passive shoulder range of motion in patients with stroke.

• 한국전문물리치료학회지
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• 제10권3호
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• pp.71-79
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• 2003

Manual tracking is an experimental paradigm that can be used to study information processing in continuous movements involving accurate, ongoing control of motor performance. The purpose of this study was to identify the effects of knee tracking training, using the paretic side, on gait in stroke patients. Nine patients with hemiplegia participated in the study. The timed 10 m gait speed test and tracking test were administrated. The tracking test was composed with ranges of $-20^{\circ}$ to $20^{\circ}$ and $0^{\circ}$ to $60^{\circ}$. The tracking training consisted of five times every week for 4 weeks. The data were analyzed by non-parametric paired sign test of Wilcoxon. The flexion/extension error of the tracking test was significantly reduced on the paretic side, while the nonparetic side was not statistically significant. The transfer of the skill to the functional activity was shown in the significant improvement at timed 10 m gait speed test. This study shows that individuals with chronic who have impaired knee movement can be trained to improve their knee control through intensive practice at a knee movement tracking task and that the skill learned from such training is transfered to a more functional gait speed.

• 대한물리의학회지
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• 제10권3호
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• pp.19-27
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• 2015

PURPOSE: This study aimed to investigate the effects of pressure sense perception training (PSPT) on various surfaces on the somatosensory system, balance, and walking ability in chronic stroke patients. METHODS: Thirty patients with stroke participated in this study and were randomly assigned to one of three groups; group 1 received the general physical therapy and the PSPT on a stable surface, group 2 received the general physical therapy and the PSPT on an unstable surface, and group 3 received the general physical therapy alone. Participants in group 1 and group 2 underwent 30 min/session, 3 days per week, for 4 weeks. Pressure error (PE) was used to evaluate changes of proprioception. The Balancia, Functional reach test (FRT), and Timed Up and Go (TUG) were used to assess the balance ability, and the 10m Walking Test (10-MWT) was used to assess walking ability. RESULTS: Experimental groups (group 1 and group 2) showed significant differences in PE, FRT, TUG, and 10-MWT compared to the control group (p <0.05). Group 2 (PSPT on an unstable surface) was significantly different in PE, FRT, and 10-MWT from group 1 (p <0.05). No significant differences were observed for other measures. CONCLUSION: Pressure sense perception training on an unstable surface might be a significantly more effective method for improving somatosensory function, balance, and walking ability, than PSPT on a stable surface.

• 한국기계가공학회지
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• 제10권6호
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• pp.50-55
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• 2011

The fluid power products are widely used in current industrial area such as automation of products and equipment assembly, high-tech machine tool, aircraft, train, and etc. As the development of industry is in progress, the development of the fluid power products is demanding and it is required in every industrial area. This research proposed a pneumatic system to evaluate displacement accuracy of the pneumatic actuator without external load and to analyze capability of integration of the valve system. The pneumatic system consisted of a combination of pneumatic actuator, four two-port valves, two three-port valves, two pressure valve, a check valve, two proximity sensors, and a program logic controller (PLC). The position controller is based on the PLC connected with the proximity sensors. The maximum air pressure applied for tests was $49.05N/cm^2$ and the displacement accuracy of a stroke was measured using a dial gauge. The supply- and discharge-side of air pressure and the length of the stroke of the pneumatic cylinder were varied The test of the position control of the pneumatic cylinder was carried out 50 times at each supply- and discharge-side air pressure of 24.53/34.34, 29.43/39.24, 34.34/44.15, and $39.24/49.05N/cm^2$ and replicated three times. The accuracy of the displacement of the pneumatic cylinder stroke increased as the supply- and discharge-side of air pressure increased with the stroke length of 133mm. Also the displacement accuracy increased as the stroke length increased with the fixed supply- and discharge-side of air pressure of the pneumatic cylinder as 34.34 and $44.15N/cm^2$, respectively. The most accurate displacement of the pneumatic cylinder was obtained at the supplyand discharge-side of air pressure of 39.24 and $49.05N/cm^2$, respectively, and strokes of 170 and 190mm.

• 한국정밀공학회지
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• 제30권3호
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• pp.254-259
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• 2013

Ball screw system is widely used as a precision mechanical linear actuator that translates rotational motion to linear motion for its high efficiency, great stiffness and long life. Recently, according to the requirements of high accuracy and stiffness, the pre-load on the ball screw which means of remove the backlash in the ball screw is usually used. Because of the preload which means the frictional resistance between the screw and nut, becomes a dominating heat source and it generates thermal deformation of ball screw which is the reason for low accuracy of the positioning decision. There are several methods to solve the problem that includes temperature control, thermal stable design and error compensation. In the past years, researchers focused on the error compensation technique for its ability to correct ball screw error effectively rather than the capabilities of careful machine design and manufacturing. Significant amounts of researches have been done to real-time error compensation. But in this paper, we developed a series of cooling methods to get thermal equilibrium in the ball screw system. So we find the optimum cooling type for improving positioning error which caused by thermal deformation in the ball screw system.

• 대한기계학회논문집A
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• 제28권2호
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• pp.149-157
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• 2004

Implicit finite element analysis of the flat surface-straight edge hemming process is performed by using a commercial code ABAQUS/Standard. Methods of finite element modeling for springback simulation and contact pair definition are discussed. An optimal mesh system is chosen through the error analysis that is based on the smoothing of discontinuity in the state variables. This study has focused on the investigation of the influence of process parameters in flanging, pre-hemming and main hemming on final hem quality, which can be defined by turn-down, warp and roll-in. The parameters adopted in this parametric study are flange length, flange angle, flanging die corner radius, face angle and insertion angle of pre-hemming punch, and over-stroke of pre-hemming and main hemming punches.

• 로봇학회논문지
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• 제18권4호
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• pp.376-384
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• 2023

In this paper, we introduce an upper extremity rehabilitation robot, NREH (NRC End-effector based Rehabilitation arm at Home). Through NREH, stroke survivors could continuously exercise their upper extremities at home. NREH allows a user to hold the handle of the end-effector of the robot arm. NREH is a end-effector-based robot that moves the arm on a two-dimensional plane, but the tilt angle can be adjusted to mimic a movement similar to that in a three-dimensional space. Depending on the tilting angle, it is possible to perform customized exercises that can adjust the difficulty for each user. The user can sit down facing the robot and perform exercises such as arm reaching. When the user sits 90 degrees sideways, the user can also exercise their arms on a plane parallel to the sagittal plane. NREH was designed to be as simple as possible considering its use at home. By applying error augmentation, the exercise effect can be increased, and assistance force or resistance force can be applied as needed. Using an encoder on two actuators and a force/torque sensor on the end-effector, NREH can continuously collect and analyze the user's movement data.

• 한국멀티미디어학회논문지
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• 제8권2호
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• pp.287-295
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• 2005

정보통신 단말기에서 한글을 쉽고 빠르게 입력 할 수 있는 방법을 모색하기 위해 한글 자음과 모음의 표기법 및 조합 원리를 분석하여 한글 자모 집합보다 작은 크기의 기본 자모 집합으로 한글을 입력하는 방법을 제시하였다 그 결과로 자음의 경우 기본 자음과 기능키를 이용하여 자음들을 조합하고, 모음은 8개의 기본모음으로부터 모음의 조합 원리 및 가획 원리에 의해 입력키가 할당되지 않은 모음을 조합하는 방식을 제안하였다. 특히, 유사 자소간의 에러 발생시에 지움 버튼을 사용하는 불편함을 해소하기 위해 자소간의 전환이 가능한 오류 수정 방식을 도입하였을 뿐만 아니라, 사용자가 입력 방식에 쉽게 익숙해질 수 있도록 입력방식을 다양화함으로써 사용자 편의 성 을 추구하였다 기존의 천지인, 나랏글 방식과 비교했을 때 사용자 편의성과 입력의 신속성, 에러 수정의 용이성 측면에서 매우 효율적임을 확인하였다.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 1989년도 한글날기념 학술대회 발표논문집
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• pp.126-131
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• 1989

본 논문에서는 Error Back Propagation 학습을 이용해 한글 문자를 On-Line 인식하는 시스템을 제안한다. Pointing device의 궤적을 추적해 입력 패턴의 특징(feature)을 추출해 신경 회로망 입력으로 준다. 이때 사용하는 특징은 기본 획 (stroke)의 종류 및 획간의 상대적 위치 관계이다. 학습과정에서는 자소의 정의를 읽어 초성, 중성, 종성에 대해 각 획수마다 정의된 신경회로망의 weight를 조정한다. 인식 과정에서는 초성, 중성, 종성의 순으로 에러가 최소인 획수의 신경회로망 출력을 택하여 2 바이트 조합형 코드로 완성한다. 이로써 Intelligent Man-Machine Interface 시스템중 위치 및 크기에 무관한 전필 입력 시스템을 구현한다.