• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.37.3-37
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• 2001

The quality of a precision product, in genera, relies on the accuracy and precision of its manufacturing and inspection process. In many cases, the level of precision in the manufacturing and inspection system is also dependent on the positioning capability of tool with respect to the workpiece in the process. Recently the positioning accuracy level employed for some of precision product has reached the level of submicron and long range of motion is required. For example, for 1GDRM lithography, 20nm accuracy and 300nm stroke needs. This paper refers to the lithography stage especially fine stage. In this study, for long stroke and high accuracy, the dual servo system is proposed. For the coarse actuator, LDM(Linear DC Noter) is used and for fine or VCM is used ...

• Design & Manufacturing
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• v.2 no.4
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• pp.11-15
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• 2008

In the sheet metal forming using a high speed press machine, driving device, such as crank, link, and knuckle mechanism, has to be designed in consideration of impact at a moment when press die contact with material, because the impact affects a dimensional accuracy of products and a life span of press die. In this study, dynamic analysis was performed using numerical simulation in order to verify the impact reduction effect for proposed double knuckle mechanism by estimating rolling and pitching moment of slide.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.87-89
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• 2001

The unbalanced reciprocation force due to armature reaction field decreases the advantage of moving coil linear motor, such as a high degree of linearity and controllability in the force and motion control. This paper firstly describes the coil inductance, and the unbalanced force. Secondly, the dynamic simulation algorithm considering the armature reaction effect and variable inductance is proposed. Thirdly, the control algorithm is proposed to reciprocate a load without mechanical spring at the required stroke and position. Finally, the validity of the proposed algorithm is confirmed by experiments.

• Journal of the Korean Society of Visualization
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• v.21 no.1
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• pp.40-46
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• 2023

For application to drag-based propulsion system, the dynamics of a segmented structure with multiple hinges undergoing oscillatory motion are investigated. The side flaps are connected to a centre rod with elastic plates acting as hinges. The hinges bend to only one direction so that the structure behave asymmetrically between the power stroke and the recovery stroke. An analytical model is proposed, which estimates the asymmetric deformation of the segmented structure coupled with hinges. Using the proposed model, the effects of key geometric and kinematic parameters on the dynamics of the structure are analyzed.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.8 no.1
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• pp.81-94
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• 2001

The purpose of this study was to identify levels of activity of daily living, self-efficacy. stroke specific quality of life and need for self-help management program for patients with hemiplegia in the home. Data were collected from June to November, 2000 and subjects were 88 poststroke patients who lived in Seoul and Kyunggi-do. The questionnaire consisted of 5 scales: activities of daily living, self-efficacy, stroke specific qulaity of life and need for a self-help management program. Data were analyzed using frequencies, percent, paired t-test, and Pearson's correlation coefficient with the SAS(version 6.12) program. The results are as follows ; 1) Most of subjects were Partially independent in ADL, but they needed assist once to do dressing, bathing meal preparation and house keeping work. 2) The mean self-efficacy score was 54.89(range : 1 to 80) and the individual differences were large. 3) Subjects responded that they were satisfied on the stroke specific quality of life scale totaled 65.8%. This value is comparatively low, especially for social role(51.4%), family functioning(58.3%) and mood (62.2%). 4) The highest needs for self-help management programs were for physical therapy, stress management, and range of motion exercise and the lowest needs were for elimination management and training, family counseling, and speech therapy. 5) On the demographic variables, sex showed significant differences for the dependent variables. Females had higher scores than males for IADL, self-efficacy, stroke-specific quality of life, and need for self-help management. 6) Age had high negative correlation with ADL, self-efficacy and stroke specific quality of life. Age was also correlated with need for self-help management. In conclusion, there was a high correlation for ADL, Self-efficacy and Quality of life in poststroke patients of home. The patient with a stroke also had a strong need for self-help management programs especially physical therapy and stress management. Therefore rehabilitation programs based on self-efficacy enhancement need to be developed in order to promote independent living for patients with hemiplegia.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1303-1306
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• 2004

We developed a symmetrical upper limb motion trainer for chronic hemiparetic subjects. This trainer enabled the practice of a forearm pronatio $n^ination and wrist flexion/extension. In this study, we have used functional magnetic resonance imaging(fMRI) with the developed symmetrical upper limb motion device, to compare brain activation patterns elicited by flexion/extension wrist movements of control and hemiparetic subject group. In control group, contralateral somatosensory cortex(SMC) and bilateral cerebellum were activated by dominant hand movement(Task 1), while bilateral movements by dominant hand(Task 2) activated the SMC in both cerebral hemispheres and ipsilateral cerebellum. However, in hemiparetic subject group, contralateral supplymentary motor area(SMA) was activated by unaffected hand movement(Task 1), while the activation of bilateral movements by unaffected hand(Task 2) showed only SMA in the undamaged hemisphere. This study, demonstrating the ability to accurately measure activation in both sensory and motor cortex, is currently being extended to patients in clinical applications such as the recovery of motor function after stroke.ke.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.163-181
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• 1998

In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

• Journal of KSNVE
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• v.10 no.4
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• pp.615-622
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• 2000

Discharge valve mechanism for an electrodynamic-oscillating compressor is different from that of a conventional reciprocating compressor. It has a larger discharge port area, heavier valve mass and stiffer valve spring comparing with the reciprocating one. Since the motion of piston is not kinematically restricted as in conventional reciprocating compressors, the stroke of the piston can change sensitively with supplied boltage and load. Thus piston can impact with discharge valve occasionally. This work deals on dynamic analysis of discharge valve considering all of those different characteristics. Impact is considered by a spring-mass model, and the pressure fluctuation at the both sides of the valve is also included considering the discharge port area and valve spring preload. It is assumed that piston moves in the region of between top and bottom dead center not by calculating piston motion from an electrodynamic equation but by getting values through experiment. Discharge pressure fluctuation is calculated using Helmholtz modeling. Finally, dynamic model for a discharge valve is constructed. In order to validate the model analysis results, the valve motion is experimentally measured and compared with analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5723-5729
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• 2013

The purpose of this study was to investigate the imbalance of muscle tone and frequent exposure to excessive gait training in patients with chronic spasticity due to stroke, the thickness of the plantar fascia to change and to evaluate. The subjects of this study was in 54 patients with chronic stroke from 18 patients Group I(MAS G0), 18 patients Group II(MAS G1), and 18 patients Group III(MAS G2) were selected. Measurement of clinical symptoms and physical examination, MAS(Modified Ashworth Scale), ultrasonographic, ROM(Range of Motion), VAS(Visual Analogue Scale), TUG(Timed Up and Go test) was measured. The study results were each group between the unaffected side and the affected side on plantar fascia thickness was statistically significantly thicker(p<.001). Each group between the unaffected side and the affected side on ankle dorsiflexion ROM was statistically significantly decrease(p<.001), VAS(p<.001), TUG(p<.001) statistically significantly increase(p<.001). In this study, the plantar fascia pathokinesiology ever presented by the contents of gait training in stroke patients is one of the information that you need to consider when presented.

• Journal of Korean Society of Neurocognitive Rehabilitation
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• v.10 no.2
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• pp.27-34
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• 2018

The purpose of this study is to investigate the effect of task training for cognitive activation of upper extremity on upper limb function and activities of daily living and to suggest intervention in rehabilitation treatment. From January to February of 2018, nine stroke patients were arbitrated 30 minutes a day, five days a week, for four weeks. For the experimental group, the therapist has induced the group using the linguistic guidance to patients, so they utilize the cognition strategy. The control group conducted active exercises in a range of motion using the instruments and passive exercises in a range of motion to reduce the stiffness of joints and upper limbs. As muscle strengthening exercises, the patients were assigned to work on the biceps muscle of arm, triceps muscle of arm, and deltoid according to the individual patient's muscular strength level. For the experimental group, the MBI was improved by ten points at maximum, and K-AMPS motor skills showed the improvements of 1.0 logit at maximum, and processing skills showed improvements of 0.6 logits at maximum. In MFT, the maximum improvement was by two points. For the control group, MBI was improved by five points at maximum, and 0.2 maximum improvements were shown in K-AMPS' motor skills and 0.3 maximum improvements in processing skills. MFT showed no change. The conclusion is that the challenges to enable training for stroke patients give a positive impact on upper limb function and activities of daily living.