• Women's Health Nursing
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• v.28 no.3
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• pp.174-186
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• 2022

Purpose: This study aimed to investigate the effects of virtual reality used in maternal-child nursing clinical practicums on nursing students' competencies through a systematic review. Methods: The inclusion criteria were peer-reviewed papers in English or Korean presenting analytic studies of maternal-child nursing practicums using virtual reality. An electronic literature search of the Cochrane Library, CINAHL, EMBASE, ERIC, PubMed, and Research Information Sharing System databases was performed using combinations of the keywords "nursing student," "virtual reality," "augmented reality," "mixed reality," and "virtual simulation" from February 4 to 15, 2022. Quality appraisal was performed using the RoB 2 and ROBINS-I tools for randomized controlled trials (RCTs) and non-RCTs, respectively. Results: Of the seven articles identified, the RCT study (n=1) was deemed to have a high risk of bias, with some items indeterminable due to a lack of reported details. Most of the non-RCT studies (n=6) had a moderate or serious risk of bias related to selection and measurement issues. Clinical education using virtual reality had positive effects on knowledge, skills, satisfaction, self-efficacy, and needs improvement; however, it did not affect critical thinking or self-directed learning. Conclusion: This study demonstrated that using virtual reality for maternal-child nursing clinical practicums had educational effects on a variety of students' competencies. Considering the challenges of providing direct care in clinical practicums, virtual reality can be a viable tool that supplements maternal-child nursing experience. Greater rigor and fuller reporting of study details are required for future research.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.45-52
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• 2016

This paper suggests a new method of finding regularization parameter for image restoration problems. Wiener filter requires priori information such that power spectrums of original image and noise. Constrained least squares restoration also requires knowledge of the noise level. If the prior information is not available, separate optimization functions for Tikhonov regularization parameter are suggested in the literature such as generalized cross validation and L-curve criterion. In this paper, self-regularization method that connects bias term of augmented linear system and smoothing term of Tikhonov regularization is introduced in the frequency domain and applied to the image restoration problems. Experimental results show the effectiveness of the proposed method.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.4
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• pp.1-9
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• 2020

PURPOSE: The current generation has shortened hamstrings due to a sedentary lifestyle, resulting in reduced flexibility of the hamstring and dysfunction. This study was undertaken to compare effects of three different release exercises on hamstring flexibility, in participants with short hamstrings. METHODS: Totally, 20 subjects having short hamstrings were involved in this study. The inclusion criterion for study participation was active knee extension test (AKET) less than 60°. All participants were subjected to 3 methods: hamstring foam roller release (HFRR), sitting self myofascial release (sitting SMR), and standing self myofascial release (Standing SMR). All participants randomly performed all three methods to avoid bias caused by learning or fatigue. Passive knee extension test (PKET), AKET, finger to floor distance test (FTFT), and pelvic tilting angle test (PTAT) were measured pre- and post-exercises. RESULTS: The PKET, AKET and FTFT were significantly increased after HFRR, sitting SMR, and standing SMR exercise (p < .05). However, PTAT was not significantly increased after the three exercises (p > .05). Furthermore, no significant differences were observed between PKET, AKET, FTFT and PTAT subsequent to HFRR, sitting SMR, and standing SMR (p > .05). CONCLUSION: Our results indicate that HFRR, sitting SMR and standing SMR were immediately effective in improving hamstring flexibility in participants with short hamstrings.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.281-285
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• 2011

We investigated the effects of tunneling current on scanning tunneling microscopy (STM) images of 1-octanethiol (OT) and 1-decanethiol (DT) self-assembled monolayers (SAMs). At a low tunneling current, the domain boundaries and ordered alkanethiol molecules were clearly resolved. As the tunneling current was increased at a constant bias voltage, however, the STM images showed disordered structures of the OT and DT SAMs. As the tunneling current was reduced back to low values, the ordered structures of the alkanethiol molecules reappeared. The reversibility of the process suggests that the sulfur head groups did not rearrange under any of the tunneling current conditions. On the basis of our observations, which are inconsistent with the standard model for STM imaging of molecules on metal surfaces, we consider the STM imaging mechanism in terms of a two-region tunneling junction model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.678-681
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• 2009

A single-pixel photon counter is designed using a folded cascode CMOS operational amplifier which is self-biased. Since there is no need for a voltage bias circuit, the layout area and power consumption of the designed counter are reduced. The signal voltage of the designed charge sensitive amplifier (CSA) with the MagnaChip $0.18{\mu}m$ CMOS process is simulated to be 138mv, near the theoretical voltage of 151mV. And the layout area of the designed counter is $100{\mu}m{\times}100{\mu}m$.

• The Journal of Korean Academic Society of Nursing Education
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• v.27 no.1
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• pp.5-15
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• 2021

Purpose: This study aimed to provide a systematic review and meta-analysis of research on flipped learning effects applied to university students. Methods: The random effect model was applied to 21 papers to calculate the effect size. To verify the moderation effect, a meta regression analysis and meta ANOVA were performed. Publication bias was verified through a funnel plot, and then an Egger's regression test was conducted. Results: The overall average effect size was .69 (95% CI: .51-.87), showing a median effect size, which was statistically significant. The outcome variables were in the order of learning motivation (Hedges' g=.83), self-directed learning (Hedges' g=.78), learning achievement (Hedges' g=.66), and efficacy (Hedges' g=.50), which were statistically significant. Conclusion: Flipped learning was found to be statistically significant in improving self-directed learning, learning motivation, efficacy, and learning achievement amng university students. It is suggestd that this method be actively applied in university education.

• Journal of Preventive Medicine and Public Health
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• v.37 no.2
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• pp.127-132
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• 2004

Objectives : Cotinine, the major metabolite of nicotine, is a useful marker of exposure to tobacco smoke and self-reporting of smoking status is thought not to be reliable. This study aimed to evaluate the agreement between the smoking self-report among adolescents and the urinary cotinine test. Methods : The study subjects were 1226 middle and high school students in Hanam city, who were selected by stratified random sampling. The self-report about smoking behavior was compared with urine cotinine value measured with PBM $AccuSign^{\circledR}fi$ Nicotine(Princeton BioMeditech Corporation, USA). The percentage agreement, kappa and 95% confidence interval(CI) were calculated. Results : The overall percentage agreement was 88.6%, and those for boys, girls, middle school, general school and vocational school students were 87.3%, 90.1%, 93.7%, 85,5%, 90.7%, and 78.4%, respectively. The overall kappa index was 0.46(95% CI=0.39-0.54)for overall, .and those for boys, girls, middle school, general school and vocational school students were 0.56(95% CI=0.48-0.65), 0.20(95% CI=0.07-0.32), 0.21(95% CI=0.09-0.34), 0.55(95% CI=0.47-0.64), 0.42(95% CI=0.33-0.52), and 0.48(95% CI=0.36-0.60), respectively. Conclusion : The percentage agreement was relatively high but the kappa values very low for girls, and middle school students. Though the prevalence bias can be influenced by these results, the self-report was not a sufficient tool for the evaluation of adolescents' smoking status, especially in girls or middle school students.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.7
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• pp.605-613
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• 2014

Scanning white-light interferometry is an important measurement option for many surfaces. However, serious profile measurement errors can be present when measuring free-form surfaces being highly curved or tilted. When the object surface slope is not zero, the object and reference rays are no longer common path and optical aberrations impact the measurement. Aberrations mainly occur at the beam splitter in the interference objective and from misalignment in the optical system. Both effects distort the white-light interference signal when the surface slope is not zero. In this paper, we describe a modified version of white-light interferometry for eliminating these measurement errors and improving the accuracy of white-light interferometry. Moreover, we report systematic errors that are caused by optical aberrations when the object is not flat, and compare our proposed method with the conventional processing algorithm using the random ball test.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.212-218
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• 2001

We experimentally investigated the dependence of extinction ratio and chirp on bias current which was injected into DFB-LD in a directly modulated 2.5 Obitls transmitter. Through the abnormal dispersion transmission, we found that transmission power penalty is minimized at 8-10 dB extinction ratio (bias current at 1.5-1.8 fold above threshold current). Also, we discussed the relation between extinction ratio and self phase modulation (SPM) through the 240 km abnormal dispersion transmission. When SPM takes effect, we obtained the best receiver sensitivity for specific system configuration at 10.4 dB and 8.4 dB extinction ratio, below and above 200km transmission distance, respectively. ively.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.10
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• pp.33-40
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• 1993

A reflection type 16x8 S-SEED array from LP(Low Pressure)-MODVD-grown GaAs/AlGaAs extremely shallow quantum well(ESQW) structures, with 4% Al fraction, has been fabricated. Its intrinsic region consists of 50 pairs of alternating 100.angs. GaAs and 100.angs. $Al_{0.04}$Ga$_{0.96}$As layers. A multilayer reflector stack of $Al_{0.04}$/Ga$_{0.96}$ As(599$\AA$)/AlAs(723$\AA$) was incorporated for the reflection plane below the p-i-n structures. The device processing after the MOCVD growth includes the mesa etching, isolation etching, insulator deposition, p & n metallization, and AR(Anti-Reflection) coating. For switching characteristics of the S-SEED in the form of p-i-n ESQW diode, the maximum optical negative resistance was observed at 856nm. Reflectance measurements showed a change from 15.6% to 43.3% for +0.9V to -6V bias. The maximum contrast ration of the S-SEED array was 2.0 and all the 128 devices showed optical bistability with contrast ratios over 2.4 at 5V reverse bias.