• The Journal of Korean Physical Therapy
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• v.33 no.2
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• pp.106-113
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• 2021

Purpose: This study examined the effectiveness of action observation training (AOT) and mirror therapy in improving the electroencephalograms (EEG) of stroke patients. Methods: Patients were allocated randomly to three groups: an action observation training with activity (AOTA) group (n=12), a mirror therapy with activity (MTA) group (n=11), and an AOT-only group (n=12). All groups received conventional physiotherapy in five 60-minute sessions over six weeks. The AOTA, MTA, and AOT groups practiced AOTA, MTA, and AOT, respectively, in three 30-minute sessions over six weeks. The differences between the pre- and post-treatment EEGs were assessed using a paired t-test. Comparisons between the groups were performed using one-way ANOVA. Results: The participants in the AOTA and MTA groups showed significant improvement in the EEG. AOTA improved the alpha waves of the prefrontal, temporal, and parietal lobes significantly (p<0.05). MTA improved the alpha waves of the temporal lobe significantly (p<0.05). AOT did not result in significant improvement Conclusion: AOTA and MTA improve stroke patients' EEGs. Mirror neuron activation combined with conventional stroke physiotherapy promotes motor recovery and functioning. The effect is enhanced when the actions are executed after observation. Further research into mirror neuron activation will be needed to develop methods to improve the EEGs of stroke patients.

• Journal of Digital Convergence
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• v.13 no.6
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• pp.205-212
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• 2015

The purpose of this study was to find out the effect that muscle activity of upper extremity and functional test in the case of the stroke patient by using the feedback mirror therapy. Sixteen subjects were recruited and randomly divided into two groups. one group was trained feedback mirror therapy and other group was action observation training. This process was carried out five times a week for eight weeks. To upper extremity test was used to MFT, FMA and in order to test UT, DM, BB, FCR, ECRL used to muscle activity. After the training, exclude FCR an upper extremity motor function of target showed significant difference between two groups and especially an experimental group showed significant muscle activity and MFT, FMA score improvement of UT, DM, BB, ECRL. Therefore, feedback mirror therapy is more upper extremity motor function and muscle activity improvement effect than action observation training.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.11
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• pp.575-580
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• 2001

In this paper, using $500\mum-thickness\; (100)\; silicon\; wafer,\; flat\; 65\mum-thickness$ silicon mirror plates were fabricated through dry etching and wet etching, and $45\mum-depth$ grooved driving electrodes were fabricated through UV-LIGA process. Four shapes of the driving electrode were fabricated: twenty four grooves of the $50\mum-width$, twelve grooves of the $100\mum-width$, six grooves of the $200\mum-width$, and no grooves on the driving electrode. Fabricated mirror plate size and spring size are $2400\times2400\times65\mum3\; and \;500\times10\times65\mum3,$ respectively. Mirror plate parts and driving electrodes were assembled into the scanning mirrors. Measured natural resonance frequencies were about 600Hz which have error within $\pm 2%$ to calculated value. Due to the squeeze effect in the narrow gap between the mirror plate and the driving electrode, measured resonance frequencies were reduced as raising the amplitude of the mirror plate. In a case of driving electrode without grooves, the resonance frequency was reduced largely, compared with a case of driving electrode with grooves. According to the experimental results, squeeze effect was smaller in the driving electrode with smaller-width and many grooves. Therefore, the driving electrode with smaller-width and many grooves was effective in low voltage and high speed operation.

• Journal of Welding and Joining
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• v.21 no.7
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• pp.65-70
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• 2003

Thermal emissivity is generally affected by surface situation of material such as roughness. In this study, the effect of surface roughness on measuring thermal emissivity is experimented. And emissivity measurement method and equipment using hemisperical mirror is also reviewed. As the result of this research, thermal emissivity increased as long as increasing surface roughness. So, surface roughness is a essential check point when we measure the emissivity.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.2
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• pp.53-60
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• 2018

PURPOSE: This study aimed to identify the effect of a backward walking exercise using a mirror on balance and gait in patients with stroke. METHODS: Twenty subjects with post-stroke hemiparesis volunteered to participate in this study. The experimental and control groups performed backward walking exercise plus conventional therapy or conventional physical therapy, respectively, for 6 weeks. Assessment instruments included the Berg Balance Scale (BBS), timed up and go test (TUG), and 10-m walking test (10MWT). Evaluation was performed before and after the 6-week training period. We conducted a paired t-test to compare the within-group changes before and after the intervention. An independent t-test was used to compare between-group differences. The statistical significance level was set at ${\alpha}=.05$ for all variables. RESULTS: The experimental group showed a significant within-group change in the BBS, TUG, and 10MWT (p<.05). The control group also showed a significant change (p<.05). A significant difference was observed between the experimental and control groups with regard to changes in the BBS, TUG, and 10MWT results after the interventions (p<.05). CONCLUSION: This study demonstrated that backward walking exercise using a mirror may be valuable for future research. Further studies with a wider range of pathology and longer experiment duration are required to validate the results of the present study.

• Korean Journal of Remote Sensing
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• v.27 no.3
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• pp.369-377
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• 2011

Since well-calibrated satellite data is critical for their applications, calibration and validation of COMS science data was one of the key activities during the IOT. COMS MI radiometric calibration process was divided into two phases according to the out-gassing of the sensor: calibrations of the visible (VI) and infrared (IR) channels. Different from the VIS calibration, the calibration steps for the IR channels followed additional processes to secure their radiometric performances. Primary calibration steps of the IR were scan mirror emissivity correction, midnight effect compensation, slope averaging and 1/f noise compensation after a nominal calibration. First, the scan mirror emissivity correction was conducted to compensate the variability of the scan mirror emissivity driven by the coating material on the scan mirror. Second, the midnight effect correction was performed to remove unreasonable high spikes of the slope values caused by the excessive radiative sources during the local midnight. After these steps, the residual (difference between the previous slope and the given slope) was filtered by a smoothing routine to eliminate the remnant random noises. The 1/f noise compensation was also carried out to filter out the lower frequency noises caused from the electronics in the Imager. With through calibration processes during the entire IOT period, the calibrated IR data showed excellent performances.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.189-196
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• 1996

We have studied sngle-frequency yield of 1.55${\mu}$m DFB lasers with uniform sinusoidal grating using an effective index transfer matrix method considering both threshold gain difference and spatial hole-burning effect. Optimum grating height and mirror reflectivities that maximize the single-frequency yield are found for a low-reflection (LR)/high-reflection(HR) mirror structure and a LR/as-cleaved miror structure for an assumed basic waveguide structure. LR/HR structure has a high yield of about 80% in a narrow range of grating height while LR/as-cleaved mirror structure has a low yield of about 50% in a relatively wide range of grating height. The effect of the low-reflection facet reflectivity is also studied.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.130-136
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• 2010

The microbolometer array sensor with fine pitch pixel array has been implemented to the released amorphous silicon layer supported by two contact pads. For the design of focal plane mirror with geometrical flatness, the simple beam test structures were fabricated and characterized. As the beam length decreased, the effect of beam width on the bending was minimized, Mirror deformation of focal plane in a real pixel showed downward curvature by residual stress of a-Si and Ti layer. The mirror tilting was caused by the mis-align effect of contact pad and confirmed by FEA simulation results. The properties of bolometer have been measured as such that the NETD 145 mK, the TCR -2 %/K, and thermal time constant 1.99 ms.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.397-401
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• 2003

In this work, diamond turning process is used to produce mirror surface on a Al cone. The Al cone as used as a mirror which can reflect a laser beam without scattering and, hence, it is critical to minimize the surface roughness of a Al cone. During diamond turning, feedrate and tool nose radius are changed to investigate characteristics of the ultra precision machined surface of a Al cone. A laser beam of 633 nm is applied to examine the effect of surface roughness on the characteristics of reflectivity. It is found that surface roughness is not significantly affected by feedrate. The main factor influencing surface roughness is tool nose radius. The line patterns of reflected laser beams show that the minimum surface roughness of 0.08 $\mu\textrm{m}$ (Ra) is required to avoid scattering phenomena of reflectivity.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.72-76
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• 2003

We developed a polarimetric fiber-optic current sensor using a length of twisted fiber and a Faraday rotator mirror which was used to suppress the linear birefringence effect. A gold coated mirror was also used as the sensor coil reflector, and the results were compared with the case of FRM. From the experimental results, it is clear that the FRM greatly enhances the stability of the fiber optic current sensor output..