• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.117-122
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• 2015

The holes with a diameter of $35{\mu}m$ inside the GMR-SV (giant magnetoresistance-spin valve) film were patterned by using the photolithography process and ECR (electron cyclotron resonance) Ar-ion milling. From the magnetoresistance curves of the GMR-SV film with holes measuring by 4-electrode method, the MR (magnetoresistance ratio) and MS (magnetic sensitivity) are almost same as the values of initial states. On other side hand, the $H_{ex}$ (exchange bias coupling field) and $H_c$ (coercivity) dominantly increased from 120 Oe and 10 Oe to 190 Oe and 41 Oe as increment of the number of holes inside GMR-SV film respectively. These results were shown to be attributed to major effect of EMD (easy magnetic domian) having a region positioned between two holes perpendicular to the sensing current. On the basis of this study, the fabrication of GMR-SV applying to the hole formation improved the magnetoresistance properties having the thermal stability and durability of bio-device.

• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.196-202
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• 2000

Top synthetic spin valves with structure Ta/NiFe/CoFe/Cu/CoFe(P1)/Ru/CoFe(P2)/FeMn/Ta on Si(100) substrate with natural oxide were prepared by dc magnetron sputtering system, and investigated on the magnetoresistance properties and effective exchange bias field. As the thickness of FeMn increased above 150 $\AA$, MR ratio was decreased due to the current shunting effect. As the thickness of free layer decreased below 40$\AA$, MR ratio was reduced rapidly. In case of 40 $\AA$ thick of free layer, spin valve film with a structure Si(100)/Ta(50 $\AA$)/NiFe(27 $\AA$)/CoFe(13 $\AA$)/Cu(26 $\AA$)/CoFe(30 $\AA$)/Ru(7 $\AA$)/CoFe(15 $\AA$)/FeMn(100 $\AA$)/Ta(50 $\AA$) exhibited maximum MR ratio of 7.5 % and an effective exchange bias field of 600 Oe, respectively. Thickness difference dependence in this synthetic spin valve structure on effective exchange field was investigated and interpreted by the analytical method. It should be noted that thickness increase of CoFe(P 1) and decrease of CoFe(P2) in synthetic antiferromagnet leaded to the decrease in effective exchange bias field by experimentally and analytically.

• Journal of Korea Technology Innovation Society
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• v.14 no.1
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• pp.22-39
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• 2011

This study examines the wage level from a viewpoint of major-job match as part of an analysis on the skill mismatch problem in 4-year college graduates. The empirical analysis explicitly incorporate the sample selection bias as an econometric problem not only suggested but merely introduced in the earlier studies. This study also set up a major-job match variable, which was usually handled as a binary variable for analytical convenience, as a polychotomous choice variable in selection equation as provided by the survey. In particular, it considered multi-cohort survey on graduates of the years 1982, 1992, and 2002 for the empirical analysis. As a result of empirical analysis, the wage premium of a major-job match was identified. This result was consistent after the consideration of a sample selection bias and also after modeling the major-job match variable as polychotomously selective. Through an analysis classified by the major, this study identified a relatively high wage premium among Social Science, Engineering, and Science majors. However, there was a difference in the effect of selection among these majors. Also, by assessing cohort effects this study found that the skill mismatch had rapidly progressed in 1992, while difference between 1992 and 2002 cohorts are insignificant. The analysis suggests that wage level is better understood within the context of both sample selection and major-job match, and regardless of model specification the major-job match affects wage strongly.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.33 no.3
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• pp.45-68
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• 2020

Objectives : This study aims to evaluate the effectiveness and safety of manual and electroacupuncture on glaucoma. Method : We searched 11 electronic databases using index words to identify randomized clinical trials. Meta-analysis of weighted mean difference (WMD) or standardized mean difference (SMD) were used to evaluate the outcomes. Cochrane bias risk assessment tool was used to assess the risk of bias in each clinical study. The collected data was analyzed using RevMan software (ver. 5.3). Results : At the initial stage of data retrieval, 549 papers were searched. After reviewing 37 full texts, a total of 10 RCT studies (426patients, 715 eyes) were selected and 8 RCT studies (357 people, 617 eyes) were involved in meta-analysis. Meta-analysis of 8 RCTs showed that acupuncture alone was more effective in reducing intraocular pressure(IOP) than conventional treatment (WMD = -5.73, 95% CI: [-12.30, 0.83], P = 0.09, I² = 97%) The combination of acupuncture or electroacupuncture with conventional treatment was also effective in lowering IOP (WMD = -1.84, 95% CI: [-2.31, -1.37], P <0.00001, I² = 45%). It was estimated that the combination of acupuncture with conventional treatment was also effective for improving visual field (VF) (WMD = -2.17, 95% CI: [-4.32, -0.02], P = 0.05, I² = 89%) but improvement in visual acuity (VA) was not significant (MD = 0.06, 95% CI: [-0.03, 0.15], P = 0.23, I² = 0%). Subgroup analyzes were performed only for the studies that used open glaucoma as the study's disease and combination of acupuncture or electroacupuncture with conventional therapy would have an effect on lowering intraocular pressure (WMD = -1.68)., 95% CI: [-2.46, -0.90], P <0.0001, I² = 29%). Conclusion : This study suggests that acupuncture treatment for glaucoma may be effective in reducing intraocular pressure and helpful in improving visual field defects. However, due to the small sample size, high risk of bias and high heterogeneity in the methodology, it is expected that further studies will be needed to verify the results. Further studies in large-scale samples based on a minimized biased methodology would be necessary.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1561-1569
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• 2006

Denaturing gradient gel electrophoresis (DGGE) is one of the most frequently used methods for analysis of soil microbial community structure. Unbiased PCR amplification of target DNA templates is crucial for efficient detection of multiple microbial populations mixed in soil. In this study, DGGE profiles were compared using different pairs of primers targeting different hypervariable regions of thirteen representative soil bacteria and clones. The primer set (1070f-1392r) for the E. coli numbering 1,071-1,391 region could not resolve all the 16S rDNA fragments of the representative bacteria and clones, and moreover, yielded spurious bands in DGGE profiles. For the E. coli numbering 353-514 region, various forward primers were designed to investigate the efficiency of PCR amplification. A degenerate forward primer (F357IW) often yielded multiple bands for a certain single 16S rDNA fragment in DGGE analysis, whereas nondegenerate primers (338f, F338T2, F338I2) differentially amplified each of the fragments in the mixture according to the position and the number of primer-template mismatches. A forward primer (F352T) designed to have one internal mismatch commonly with all the thirteen 16S rDNA fragments efficiently produced and separated all the target DNA bands with similar intensities in the DGGE profiles. This primer set F352T-519r consistently yielded the best DGGE banding profiles when tested with various soil samples. Touchdown PCR intensified the uneven amplification, and lowering the annealing temperature had no significant effect on the DGGE profiles. These results showed that PCR amplification bias could be much improved by properly designing primers for use in fingerprinting soil bacterial communities with the DGGE technique.

• Journal of Korean Medicine Rehabilitation
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• v.29 no.3
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• pp.15-33
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• 2019

Objectives The objective of this study is to provide the evidence of the effectivness of herbal medicine for frozen shoulder. Methods 2 Korean medical on-line databases (Oriental Medicine Advanced Searching Integrated System, Korean Traditional Knowledge), and 3 foreign databases (Pubmed, Cochrane library, China National Knowledge Infrastructure) were searched to find articles concerning herbal medicine for frozen shoulder. We selected randomized controlled trials (RCTs). Several repeated articles and those not relevant to the topic were excluded, as well as review articles and commentaries. The methodological quality of RCTs were evaluated using the Cochrane risk of bias tool and meta-analyes were perfomed. Results Total 474 studies were founded and 22 RCTs were selected for systematic review. Efficiency rate was used as the primary evaluation method. Almost studies reported that herbal medicine has significant effect on pain reduction, increasing shoulder function on frozen shoulder. 3 studies comparing herbal medicine and chuna with chuna and 3 studies comparing herbal medicine with ibuprofen were included in the meta-analysis. At herbal medicine and chuna with chuna meta-analysis, it showed positive results of herbal medicine for efficiency rate (risk ratio: 1.18, 95% confidence interval: 1.09-1.27, p<0.0001). At herbal medicine with ibuprofen medta-analysis, it showed positive results of herbal medicine for efficiency rate (risk ratio: 1.15, 95% confidence interval: 1.05-1.27, p=0.003). Conclusions The studies showed that herbal medicine can significantly effective on frozen shoulder. However, the risk of bias in RCTs were evaluated as uncertain. In the future, further well-designed RCTs are needed to prove the effectiveness of herbal medicine for frozen shoulder and reduce the risk of bias.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.161-171
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• 2021

According to the equity home bias theory, foreign investors are considered to have less information than native investors. However, as the economy becomes liberalized and overseas economic innovation has a great influence on the local economy, it is possible for foreign investors to invest as informed traders. This study analyzes whether information on trade amount by nationality has specific characteristics. The findings are summarized as follows. First, the increase in trading by foreign investors has negative effects on stock returns. There is no significant difference in these negative effects by nationality. This means that foreign investors show strong herd behavior regardless of nationality. Second, foreigners' investment activities increase stock price volatility, but the impact is not significant. Third, the behavior of foreign investors is still positive feedback. However, there are signs that positive feedback behavior may be changing, especially for funds from the United States and the Cayman Islands. Finally, tax haven zone funds have different investment strategies than other foreign investors. However, Cayman Islands funds, which are estimated to be closely related to Korea, are different from Luxembourg and Ireland funds. These findings undermine the fundamentals of the equity home bias theory.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.35 no.4
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• pp.139-162
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• 2022

Objectives : The review was conducted to validate the effectiveness of herbal medicines on acne. Methods : Randomized controlled trials(RCTs) reporting the effects of herbal medicine treatment on acne were searched through seven electronic databases from the time of application of the material to October 2021. Cochrane Collaboration's Risk of Bias was used to assess the risk of bias. Analysis was performed using Review Manager 5.4 and R 4.1.0 Meta, Metafor program. Results : 34 RCTs was selected and meta-analysis was performed with 30 studies. The inflammatory lesion count of the herbal medicine(MD=0.29, 95% CI:-0.59-0.01, p<0.01, I²=80%) and the non inflammatory lesion count of herbal medicine(MD=-0.30, 95% CI:-0.70-0.10, p<0.01, I²=78%) were seen. The score of IGA(RR=1.43, 95% CI:0.90-2.27, p<0.91, I²=0%), VISIA(MD=0.36, 95% CI:0.21-0.51, p=0.07, I²=40%), effective rate(RR=1.23, 95% CI:1.05-1.44, p<0.01, I²=98%), DLQI(MD : 0.59, 95% CI:0.14-1.04, p=0.07, I²=63%) and recurrence rate(RR=0.36, 95% CI:0.23-0.58, p=0.73, I²=0%) were seen. The effective rate of herbal medicine were statistically higher that of the control group(WM)(RR=1.19, 95% CI:1.04-1.37, p<0.01, I²=97%). As a result of dividing the treatment groups into OHM, EHM, and OEHM, the EHM group(RR=1.17, 95% CI:0.79-1.72, p<0.01, I²=99%) showed the most statistically significant effect. The overall risk of bias of the included studies was some concerns. No serious adverse effects were observed. Conclusions : This review found the effectiveness of herbal medicine for acne.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.6
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• pp.222-232
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• 2022

In this study we investigated the characteristics of long-term tidal constituents based on 30 tidal gauge data along the coasts of Korea and its the effects on total water level (TWL) forecasts. The results show that the solar annual (Sa) and semiannual (Ssa) tides were dominant among long-term tidal constituents, and they are relatively large in western coast of Korea peninsula. To investigate the effect of long-term tidal constituents on TWL forecasts, we produced predicted tides in 2021 with and without long-term tidal constituents. The TWL forecasts with and without long-term tidal constituents are then calculated by adding surge forecasts into predicted tides. Comparing with the TWL without long-term tidal constituents, the results with long-term tidal constituents reveals small bias in summer and relatively large negative bias in winter. It is concluded that the large error found in winter generally caused by double-counting of meteorological factors in predicted tides and surge forecasts. The predicted surge for 2021 based on the harmonic analysis shows seasonality, and it reduces the large negative bias shown in winter when it subtracted from the TWL forecasts with long-term tidal constituents.

• Journal of Korean Medicine Rehabilitation
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• v.33 no.3
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• pp.135-148
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• 2023

Objectives To investigate the effectiveness of acupuncture in the treatment of post-disaster musculoskeletal pain by reviewing relevant clinical studies. Methods A systematic search was conducted across 10 electronic databases to identify relevant clinical studies on acupuncture treatment for post-disaster musculoskeletal pain until May 2023. The methodological quality was evaluated using the Cochrane Risk of Bias 2 and Risk of Bias Assessment tool for non-randomized studies tools. Results Six articles were analyzed, including two randomized controlled trials (RCTs), two before-after studies, one qualitative research, and one case series. Overall, acupuncture therapy showed some improvement in pain scale among musculoskeletal pain survivors. However, no significant improvement was observed in the Short-Form McGill Pain Questionnaire (SF-MPQ-2). Subgroup analysis of participants who completed at least four acupuncture sessions revealed a significant effect on the SFMPQ-2. Additionally, a significant improvement in 36-Item Short Form Survey (SF36P) was observed after 6 months of treatment, but the 2-month treatment period did not show statistically significant effects on SF-36P improvement. The evaluation of the methodological quality of the RCTs identified some concerns of bias. Conclusions The results suggest that acupuncture is effective in alleviating post-disaster musculoskeletal pain. However, considering the limited number of selected studies and the inclusion of subjective evaluation measures, caution should be exercised in interpreting the results. Further large-scale follow-up studies are needed to determine the optimal frequency and duration of acupuncture treatment. Well-designed controlled trials should be conducted to provide more robust evidence regarding the effectiveness of acupuncture for post-disaster musculoskeletal pain.