• Journal of Mechanical Science and Technology
• /
• v.18 no.7
• /
• pp.1055-1061
• /
• 2004

In this research, a vision system for detecting breakages of small-diameter taps, which are rarely detected by the indirect in-process monitoring methods such as acoustic emission, cutting torque and motor current, was developed. Two HMI (Human Machine Interface) programs to embed the developed vision system into a Siemens open architecture controller, 840D, were developed. They are placed in sub-windows of the main window of the 840D and can be activated or deactivated either by a softkey on the operating panel or the M code in the NC part program. In the event that any type of tool breakage is detected, the HMI program issues a command for an automatic tool change or sends an alarm signal to the NC kernel. An evaluation test in a high-speed tapping machine showed that the developed vision system was successful in detecting breakages of small-diameter taps up to M1.

• Steel and Composite Structures
• /
• v.44 no.3
• /
• pp.423-436
• /
• 2022

This paper proposes an innovative thin-walled square concrete filled steel tubular (CFST) column with an octagonal/circular lining steel tube, in which the outer steel tube and the inner liner are fabricated independently of each other and connected by slot-weld or self-tapping screw connections. Twelve thin-walled square CFST columns were tested under quasi-static loading, considering the parameters of liner type, connection type between the square tube and liner, yield strength of steel tube, and the axial load ratio. The seismic performance of the thin-walled square CFST columns is effectively improved by the octagonal and circular liners, and all the liner-stiffened specimens showed an excellent ductile behavior with the ultimate draft ratios being much larger than 1/50 and the ductility coefficients being generally higher than 4.0. The energy dissipation abilities of the specimens with circular liners and self-tapping screw connections were superior to those with octagonal liner and slot-weld connections. Based on the test results, both the finite element (FE) and simplified theoretical models were established, considering the post-buckling strength of the thin-walled square steel tube and the confinement effect of the liners, and the proposed models well predicted the hysteretic behavior of the liner-stiffened specimens.

• Sleep Medicine and Psychophysiology
• /
• v.8 no.2
• /
• pp.129-137
• /
• 2001

Objectives: The purpose of this study is to investigate the effects of 38-hour sleep deprivation on fine motor performance. The Motor Performance Series (MPS) in the Vienna Test System (computerized neurocognitive function tests) was used in this study. Methods: Twenty four subjects participated in this study. Subjects had no past history of psychiatric disorders and physical illness. Subjects had normal sleep-waking cycle without current sleep disturbances and were all right-handed (Annett's Hand Preference Questionnaire: above +9 points). To minimize the learning effects, familiarization with the Vienna Test System was performed one day before the study. Subjects were to get up at 6:00 in the morning after getting enough sleep according to his or her usual sleep-wake cycle. After awakening, subjects remained awake for 38 hours under continuous surveillance. During two consecutive study days, the subjects tested MPS at 7 AM and 7 PM each day, which means the MPS was done four times in total. During the experiment, anything that could affect the subjects' sleep such as coffee, tea, alcohol, a nap, tiring sports, and all medications were prohibited. Results: In MPS, the fine motor functions of both hands decreased after 38 hours of sleep deprivation. The decrement in motor performance was prominent in the dominant right hand. In the right hand, the total number of tapping was reduced (p<.005), and the number of misses (p<.05) and the length of misses (p<.05) of line tracking, the total length of inserting a short pin (p<.01), the total length of inserting a long pin (p<.05), and the number of misses in aiming (p<.05) increased. Such performance decrement was distinct in the morning sessions. Conclusions: These results suggest that fine motor performance decrement during sleep deprivation is predominant in the right hand, which exerts maximal motor function. The finding of decrement in motor function in tapping during sleep deprivation also suggested that the time required for exhaustion of muscles is shortened during sleep deprivation. More deterioration of motor performance was shown in the morning, which could be explained as circadian rhythm effects.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.05a
• /
• pp.215-218
• /
• 2001

태핑 검사법을 이용한 복합재료 구조물의 손상검사 과정을 수치해석을 이용하여 모사하였다. 타격체에 의한 태핑을 모사하기 위해 동적접촉 알고리듬을 이용한 유한요소법을 이용하였다. 손상의 유무를 판별하는데 사용되는 척도로서 타격체와 구조물의 접촉하중의 시간이력을 계산하였다. 손상이 없는 복합재료 평판과 층간 분리 손상이 있는 복합재료 평판에 대한 해석을 통하여 접촉특성의 변화를 고찰하였다. 또한 태핑 검사법의 민감도에 대한 해석도 수행하였다.

• Sleep Medicine and Psychophysiology
• /
• v.1 no.1
• /
• pp.76-86
• /
• 1994

Objectives: This research was performed in order to observe the neuropsychological implication and functional anatomical source of event related potentials(ERP) by studying of correlations between event related potentials and neuropsychological tests. Methods: The latency and voltage of P100 of visual evoked potential (VEP), and N120 and P300 of event related potentials were studied in 56 patients and their correlations with neuropsychological tests were computed. Results: The tests showing significant correlation with latency P100 were visual continous performance test(VCPT) and contingent continous performance test(CCPT) without any significant correlation with voltage of P100. In latency of N120 category test and verbal IQ of KWIS showed significant correlation, and in voltage of N120, finger tapping test, VCPT, CCPT and digit symbol test displayed significant correlations. The latency of P300 had significant correlation with trail making A test and Stroop test. In the voltage of P300 significant correlations were shown with trail making B test, digit symbol test and Wechsler memory scale, finger tapping test, stroop test, VCPT and CCPT. Conclusion : N120 may be considered to reflect the function of medial frontal lobe and P300 may be considered to be developed from the subcortical connection of medial temporal lobe, hippocampus, thalamus, basal ganglia and medial frontal lobe.

• Journal of Preventive Medicine and Public Health
• /
• v.27 no.3 s.47
• /
• pp.487-504
• /
• 1994

A cross-sectional study was performed to evaluate the effects of chronic low-dose solvent on neurobehavioral performance of 118 male car painters. A control group of 113 workers matched for age was selected from different sections of the factory. The mean age and the mean duration of employment were 33 years and 6.7 years in both groups. Mean years of education were 11.4 years in car painters and 11.8 years in controls. Each worker completed a medical and occupational questionnaire and four tests of Swedish performance evaluation system. These included simple reaction time, symbol digit, digit span and finger tapping speed. Althougth the mean duration of employment was 6.7 years, comparison of mean performance showed a significantly poorer performance on simple reaction time (p<0.05), symbol digit(p<0.01) and digit span(p<0.05) in car painters. In univariate analysis, age and educational level contributed to poorer performance on symbol digit and digit span. Smoking appeared to slow finger tapping speed in car painters. Performance of four tests of car painters exposed to high level of solvent was poorer than that of car painters exposed to low level. In multiple regression models, controlling for age, alcohol, smoking and shift work, solvent exposure was found to be associated with performance of simple reaction time, symbol digit and digit span and exposure to high level of solvent was related to poorer performance of symbol digit and digit span.

• Steel and Composite Structures
• /
• v.7 no.1
• /
• pp.35-52
• /
• 2007

The cold formed light-gauge profiled steel sheeting can offer considerable shear resistance acting in the steel building frame. This paper conducted the full-scale test on the shear behavior of stressed skin diaphragm using profiled sheeting connected by the self-tapping screws. A three-dimensional finite element model that simulates the stressed skin diaphragm was developed. The sheet was modeled using thin element model while the supporting members were simulated using beam elements. Fasteners were represented in the numerical model as equivalent springs. A joint test program was conducted to characterize the properties of these springs and results were reported in this study. Finite element model of the full-scale test was analyzed by use of the ANSYS package, considering nonlinearity caused by the large deflection and slip of fasteners. The experimental data was compared with the results acquired by the EUR formulas and finite element analysis.

• Journal of Korean Academy of Nursing
• /
• v.39 no.1
• /
• pp.107-115
• /
• 2009

Purpose: The purpose of this study was to identify the effects of an exercise program on frontal lobe cognitive function in seniors. Methods: The participants were 42 seniors using a health center in Seoul (experimental group) and 28 seniors using a facility for elders in Seoul (control group). The exercise program was carried out for 16 weeks from April to August 2007. The frontal lobe cognitive function, which includes short term memory, attention, immediate memory, delayed memory, verbal fluency and motor function, was measured by the Digit Span Forward test, Trail Making test, Immediate recall words test, Delayed recall words, Controlled oral word association test and Finger tapping test. The collected data were analyzed by Fisher's exact test, Chi-square, t-test, and ANCOVA using the SAS program. Results: The major findings of this study were as follows: Attention (p=.009), immediate memory (p=.005), delayed memory (p=.009), and verbal fluency (p=.004) improved after the exercise program. Conclusion: In this study, the exercise program was effective in improving frontal lobe cognitive function in elders. So it provides basic information for further nursing education on exercise programs which will be effective for prevention of early cognitive function decline in normally aging elders.

• The Journal of Korean Academy of Sensory Integration
• /
• v.14 no.2
• /
• pp.1-10
• /
• 2016

Objective: This study aims investigating the effects of functional electrical stimulation (FES) on hand function of children with spastic cerebral palsy. Methods: The participants of this study are 20 children with spastic cerebral palsy aged between 11 to 16 years old. All the subjects underwent 24 sessions of FES during 8 weeks. Each FES was 20 minutes per session, and 3 sessions of FES were provided in a week. Measurements used to assess hand function are Jebsen Hand Function Test, Modified Ashworth Scale and 3D Motion Analysis. After establishment of the baseline for each client by all the measurements, reevaluations were performed every 2 weeks using Jebsen Hand Function Test and the Modified Ashworth Scale. The 3D Motion Analysis was performed only before- and after the 8 weeks of FES treatment. Results: After the FES, there was significant decrease in completed time for the all 6 subtasks of Jebsen Hand Function Test were (p<.05) and also significant decrease in spasticity score of Modified Ashworth Scale as well (p<.05). 3D Motion Analysis showed that the hand tapping and the finger tapping has been significantly improved (p<.05), and the pronation-supination movement of lower arm has been significantly improved as well. Conclusion: Based on the results of this study, it is evidenced that functional electrical stimulation is effective treatment for hand function of children with cerebral palsy. For future research, it is recommended to examine various protocols of FES including impact of long-term application.

• The Journal of Korean society of community based occupational therapy
• /
• v.7 no.1
• /
• pp.25-35
• /
• 2017

Objective : The aims of this study was to investigate the effects of modified constraint induced movement therapy(CIMT) on upper extremities function of children with hemiplegic cerebral palsy. Methods : The participants of this study are 4 children with hemiplegic cerebral palsy aged between 8 to 11 years old. During the modified CIMT period, the unaffected hand of the subjects was restrained by a hand splint for 8 weeks, five days per week, five hours a day. And the affected upper extremity was strongly trained by performing functional tasks, which were individually structured use of the affected arm. Measurements used to assess hand function are Jebsen Hand Function Test, and 3D Motion Analysis. The Jebsen Hand Function Test was performed repeatedly every two weeks. The 3D Motion Analysis was performed before and after the 8 weeks of modified constraint induced movement therapy. Results : After the modified CIMT, there was a significant improvement in completed time for the 6 tasks of Jebsen Hand Function Test(p<.05). 3D Motion Analysis was that the finger tapping and the hand tapping has been significantly decreased (p<.05), and the pronation-supination movement has been significantly increased as well(p<.05). Conclusion : In the results of this study, it is evidenced that modified CIMT is effective treatment for upper extremities function of children with hemiplegic cerebral palsy. For future research, it is recommended to examine various periods and protocol of modified CIMT including impact of long periods application.