• Journal of the Korean Magnetics Society
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• v.18 no.4
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• pp.147-153
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• 2008

It has been well-known that the Fe/GaAs heterostructure has a small lattice mismatch of 1.4% between Fe and GaAs, and the Fe layer is grown epitaxially on the the GaAs substrate. There are rich physics are observed in the GaAs/Fe interface, and the spininjection is actively studied due to its potential applications for spintronics devices. We fabricated Fe wedge layer in the thickness range $0{\sim}3.4$ nm on the GaAs(100) surface with 5-nm thick Au capping layer. The magnetic anisotropy of the Fe/GaAs system was investigated by employing Brillouin light scattering(BLS) measurements in this study. The spin wave excitation of Fe layer was studied as the function of intensity and the in-plane angle of external magnetic field, and thickness of Fe layer. Also these various dependences were analyzed with analytic expression of spin wave surface mode in order to determine the magnetic anisotropies. It has been found that the GaAs/Fe/Au system has additional uniaxial magnetic anisotropy, while the bulk Fe has biaxial anisotropy. The uniaxial anisotropy shows increasing dependency respected to decreasing thickness of Fe layer while biaxial anisotropy is reduced with Fe film thickness. This result allows the analysis that the uniaxial anisotropy is originated from interface between GaAs surface and Fe layer.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.606-612
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• 2003

The self-imaging effect or lensless imaging effect of a phase line grating is theoretically analyzed by using Fresnel diffraction theory, then experimentally investigated. The self-imaging distance $z_{T,p}$, that is the imaging distance being perfectly copied from the phase distribution of the phase grating to its intensity distribution with the magnification of 1X, can be uniquely defined as the (4n-3) $z_{T,a}$/4(n=positive integers), where rte is the well-known self-imaging distance of an amplitude grating. When the coherent laser beam is illuminated at the phase grating, the self-imaged images were obtained at $z_{T,p}$= $z_{T,a}$/4 and $z_{T,p}$=5 $z_{T,a}$/4 without any optics. On the other side, the phase-reversed self-imaging was obviously observed at $z_{T,p}$ = 3 $z_{T,a}$/4. The visibility of self-imaged images of a phase line grating as a function of the number of slits of the input grating was measured by the FFT(Fast Fourier Transform) results of the self-imaging images. As a result a stationary maximum visibility of V = 0.10 can be obtained from a grating with more than 15 slit pairs.n 15 slit pairs.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1096-1107
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• 2018

The purpose of this study was to investigate the effects of combined exercise on blood inflammatory factors, DHEA-s and arterial stiffness in elderly women. The subjects were 42 elderly females volunteers, aged 70 to 85 years, composed of the combined exercise group (n=21) and control group (n=21). The 60 minute combined exercise program(aquarobics 1 time/week, strength exercise 2 times/week) was performed 3 times per week for 12 weeks, and the intensity was progressively increased every 4 weeks(1-4 weeks: RPE 12 to 13, 5-8 weeks: RPE 13 to 14, 9-12weeks: RPE 14 to 15). The test data were analyzed by two-way repeated measures ANOVA, paired t-test, independent t-test and the alpha level of .05 was set for all tests of significance. As a result, the combined exercise for 12 weeks reduced the inflammatory response of elderly women, and DHEA-s was found to have a positive effect on aging hormone. The arterial stiffness decreased the central arterial blood pressure (systolic and diastolic), prevented the increase of the pulse pressure and the wave increase index, and decreased the pulse wave velocity. These results suggest that regular and continuous combined exercise may be recommended for the healthy aging and longevity of elderly women by inducing anti-inflammation effect and improving the aging hormonal function and the vascular health.

• Journal of the Korea Computer Graphics Society
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• v.27 no.3
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• pp.31-42
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• 2021

We propose a deep learning-based method that can estimate an appropriate lighting of both indoor and outdoor images. The method consists of two networks: Crop-to-PanoLDR network and LDR-to-HDR network. The Crop-to-PanoLDR network predicts a low dynamic range (LDR) environment map from a single partially observed normal field of view image, and the LDR-to-HDR network transforms the predicted LDR image into a high dynamic range (HDR) environment map which includes the high intensity light information. The HDR environment map generated through this process is applied when rendering virtual objects in the given image. The direction of the estimated light along with ambient light illuminating the virtual object is examined to verify the effectiveness of the proposed method. For this, the results from our method are compared with those from the methods that consider either indoor images or outdoor images only. In addition, the effect of the loss function, which plays the role of classifying images into indoor or outdoor was tested and verified. Finally, a user test was conducted to compare the quality of the environment map created in this study with those created by existing research.

• Journal of Korean Society of Disaster and Security
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• v.13 no.4
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• pp.25-36
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• 2020

An increasing frequency and intensity of natural disasters have been observed due to climate change. To better prepare for these, the MOIS (ministry of the interior and safety) announced a comprehensive plan for minimizing damages associated with natural disasters, including drought and heavy snowfall. The spatial-temporal pattern of snowfall is greatly influenced by temperature and geographical features. Heavy snowfalls are often observed in Gangwon-do, surrounded by mountains, whereas less snowfall is dominant in the southern part of the country due to relatively high temperatures. Thus, snow depth data often contains zeros that can lead to difficulties in the selection of probability distribution and estimation of the parameters. A generalized mixture distribution approach to a maximum snow depth series over the southern part of Korea (i.e., Changwon, Tongyeoung, Jinju weather stations) are located is proposed to better estimate a threshold (𝛿) classifying discrete and continuous distribution parts. The model parameters, including the threshold in the mixture model, are effectively estimated within a Bayesian modeling framework, and the uncertainty associated with the parameters is also provided. Comparing to the Daegwallyeong weather station, It was found that the proposed model is more effective for the regions in which less snow depth is observed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.7
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• pp.787-797
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• 2020

The marine officer plays a pivotal role in the shipping organization as a professional who performs a complex and diverse function. On the sea, unlike land duty, the possibility of turnover increases due to characteristics such as living in isolated spaces, continuous shift work during a set sailing period, high intensity work tension, stress, and social isolation. In this study, the impact of the organization's civic actions on the intention of turnover as a mediator of organizational immersion was divided into three groups of large companies, small and medium-sized enterprises, and public enterprises to check the differences between each category in a structural manner. Analysis showed that there were statistically significant differences between the groups in loyalty and turnover intention when the sub-factors of organizational commitment and organizational citizen behavior of the marine officer, and the size of turnover intention were included. Organization citizen behavior did not directly affect turnover intention, but when indirect effects were included, there was an effect through loyalty, and relationship-oriented organizational citizen behavior negatively affected turnover intention through loyalty. Excluding public enterprises, the non-standardization path coefficients were -0.229±0.117 and -0.319±0.068, respectively, showing a statistically significant effect in large companies and SMEs. These results indicate that in order to lower the employee turnover intention in large corporations and small and medium-sized shipping companies, it is necessary to consider not only organizational citizen behavior but also measures to increase organizational commitment.

• Korean Journal of Optics and Photonics
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• v.32 no.1
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• pp.1-8
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• 2021

We have studied a tiled-aperture coherent-beam-combining system based on constructive interference, as a way to overcome the power limitation of a single laser. A 1-watt-level, 3-channel coherent fiber laser and a 3-channel fiber array of triangular tiling with tip-tilt function were developed. A monitoring system, phase controller, and 3-channel phase modulator formed a closed-loop control system, and the SPGD algorithm was applied. Eventually, phase-locking with a rate of 5-67 kHz and peak-intensity efficiency comparable to the ideal case of 53.3% was successfully realized. We were able to develop the essential elements for a tiled-aperture coherent-beam-combining system that had the potential for highest output power without any beam-combining components, and a multichannel coherent-beam-combining system with higher output power and high speed is anticipated in the future.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.555-564
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• 2021

Thalamus is known to play an important role in the regulation of nerve function. Thalamus, located in the center of the brain, is involved in sleep, arousal, and emotional regulation, and has been reported to be associated with multiple sclerosis, essential tremors, and neurodegenerative diseases such as Parkinson's disease. In addition, it has been reported that iron deposits in the thalamus can cause depressive symptoms with age. Although there are discrepancies between studies, it can be deduced that the thalamus region has a clear effect on neurological disorders due to a strong relationship between the thalamus and neurological functions such as emotional control and processing. Through tractography analysis, the connectivity between the detailed areas of each subcortical region was investigated in the form of a matrix, showing strong connectivity and weak interhemispheric connectivity. In the 59> group, the WM connectivity of thalamus was found to be weaker than those of the two groups. Comparisons between the two groups showed that the young groups (10-39 and 40-59) had higher connection intensity than the 59> group and that statistically significant differences in 3 connection pathways were found in each hemisphere. A decrease in thalamus-related connection strength in aging has shown that it can affect emotional and neurological disorders such as anxiety and depression, and network measurements can help assess cognitive impairment across clinical conditions.

• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.117-126
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• 2020

Total knee arthroplasty is performed widely in degenerative arthritis of the knee joint, and the frequency of use is increasing. Efforts should be made to achieve functional recovery, such as returning to daily life, and the recovery of strength and range of motion after surgery. The procedure should be approached from a range of perspectives, such as patient factors, surgical technique and rehabilitation. The patient's age, degree of obesity, sex, and strength of the quadriceps muscle can affect the functional recovery after surgery. In addition, the patient's mental state, such as expectation value and satisfaction, can also have an effect. For functional recovery, patient education, pain control, and strengthening of the quadriceps muscle can be performed prior to surgery. Postoperative physiotherapy, such as icing and compression, transcutaneous electrical nerve stimulation therapy, neuromuscular electrical stimulation therapy, low frequency low intensity magnetic field therapy, strengthening of quadriceps muscle, and range of motion exercise can also be applied. In recent years, hydrotherapy, which restores the strength and balance of the leg, is being performed increasingly. These treatments are not only performed shortly after surgery, but are also performed continuously. In addition, the surgeon should apply it appropriately considering the patient's condition, compliance, and social and psychological conditions.

• Therapeutic Science for Rehabilitation
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• v.12 no.4
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• pp.67-80
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• 2023

Objective : This study aimed to investigate the current status of physical therapy in children and adolescents. Methods : Sixty questionnaires from physical therapists treating children and adolescents with disabilities were analyzed. The questionnaire consisted of questions on physical therapy, participants, satisfaction, and the assessment of pediatric and adolescent physical therapy. Descriptive statistics and frequencies were used to investigate the current status, participants, and satisfaction. Differences between physical therapy participation difficulty, importance-ability of major aspects of pediatric and adolescent physical therapy, and therapy goal frequency were analyzed using paired T-test. Results : 11 to 15 cases (66.7%) and one-on-one treatment (95.0%) were performed independently (95.0%). The main ages of the subjects were preschool and school, the diagnoses were brain lesions and developmental delay, and treatment was conducted for up to 20 years or older. Satisfaction with pediatric and adolescent physical therapy was high (70.0%), as was the intensity of work (71.7%). Neurodevelopmental therapy, gait training, and goal-directed rehabilitation were the main treatments, and Gross Motor Function Measures of 88 and 66, respectively, were used. Respondents said that current fee system is inadequate (66.1%) and appropriate fee system is needed. Conclusion : This study extensively investigated the content of and factors related to pediatric and adolescent physical therapy. Based on the current situation, efforts to improve the expertise and continuity of pediatric and adolescent physical therapists and apply the latest treatment techniques are required.