• Journal of Korean Society for Atmospheric Environment
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• v.17 no.5
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• pp.395-405
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• 2001

To make an assessment of the compatibility between DOAS and conventional point monitoring system (MCSAM-2: MS2), we investigated the concentrations of three criteria pollutants which include S $O_2$, N $O_2$, and $O_3$from a national monitoring station in Seoul during the periods of June 1999~August 2000. The average concentration values for the whole study period derived from hourly concentration data sets of those three species indicated that the mean differences between the two methods can be approximated as 18%. When the bias structure of two systems was evaluated through the computation of percent difference(PD) between the two such as ( $C_{DOAS}$- $C_{conventional}$ $C_{DOAS}$*100, differences between the two systems appeared to be quite systematic among different compounds. While the mode of bias peaked at 0~20% or 20~40% in terms of PD values, the cause of such positive bias mainly arised from generally enhanced concentration values of DOAS system. The structure of bias among different species was further assessed through linear regression analysis. Results of the analysis indicated that the dominant portions of differences observed from two monitoring systems can be accounted for by the systematic differences in their spanning and zeroing systems. S $O_2$(MS2)=0.6385 S $O_2$(DOAS)+2.0985($r^2$=0.7894) N $O_2$(MS2)=0.6548 N $O_2$(DOAS)+7.437($r^2$=0.7687) $O_3$(MS2)=1.0359 $O_3$(DOAS)-7.7885($r^2$=0.7944) The findings of slope values at around 0.64~0.65 from two species suggest that DOAS should respond more sensitively in upper bound concentration range. The offset values apart from zero indicate that more deliberate comparison needs to be made between these monitoring systems. However, based on the existence of strong correlations from at least 8,000 data points for each species of comparison, we were able to conclude that the compatibility of two monitoring systems is highly significant. With the improvement of calibration techniques for the DOAS system. its applicability for routine monitoring of airborne pollutant species is expected to be quite extendable.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.1
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• pp.1-8
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• 2004

The INS(Inertial Navigation System) provides high rate position, velocity and attitude data with good short-term stability while the GPS(Global Position System) provides position and velocity data with long-term stability. By integrating the INS with GPS, a navigation system can be achieved to Provide highly accurate navigation Performance. For the best performance, time synchronization of GPS and INS data is very important in GPS/INS integrated system But, it is impossible to synchronize them exactly due to the communication and computation time-delay. In this paper, to reduce the error caused by the measurement time-delay in GPS/INS integrated systems, error compensation methods using separate bias Kalman filter are suggested for both the loosely-coupled and the tightly-coupled GPS/INS integration systems. Linearized error models for the position and velocity matching GPS/INS integrated systems are Int derived by linearizing with respect to its time-delay and augmenting the delay-state into the conventional state equations for each case. And then separate bias Kalman Inter is introduced to estimate the time-delay during only initial navigation stage. The simulation results show that the present method is effective enough resulting in considerably less position error.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.33 no.4
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• pp.74-99
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• 2020

Objectives : The purpose of this study is to assess the effectiveness and safety of Socheongryong-tang(SCRT) for allergic rhinitis(AR). Methods : We searched randomized controlled trials(RCTs) that used SCRT for AR in 8 databases(PubMed, Cochrane Library, CNKI, CiNii Articles, OASIS, NDSL, KISS, KMbase) from their inception until August 2019. The primary outcome was effective rate and scores evaluating the improvement of AR symptoms. The secondary outcome was quality of life scale, adverse events, recurrence rate, and laboratory indicators. Two researchers assessed the risk of bias in the included trials through the Cochrane Risk of Bias tool independently. The study synthesized outcomes using RevMan 5.3. Results : Eighteen RCTs involving 1686 participants were included in this review. The risk of bias was unclear for the majority of the included studies. Meta-analysis of 12 RCTs showed that there was no statistically significant difference between the SCRT group and usual care group in the effective rate(RR 1.18, 95% CI(0.98, 1.41), p=0.09, I²=46%). Meta-analysis of 5 RCTs showed that the combination treatment group of SCRT and usual care was significantly higher than the usual care group in the effective rate(RR 1.24, 95% CI(1.12, 1.38), p<0.0001, I²=0%). The SCRT group was more effective in improving nasal symptoms and quality of life than the placebo group according to one RCT. Mild adverse events such as dry mouth were identified in 5 RCTs, but no serious adverse events were reported. Conclusion : This review showed that in terms of the effective rate for AR, there was no statistically significant difference between SCRT and usual care and the combination treatment of SCRT and usual care was more effective than usual care. There were no serious adverse events. However, it is difficult to make a definite conclusion because of few included studies and heterogeneity between studies, and the quality of included studies was mostly insufficient. Further well-designed randomized controlled trials are needed.

• Atmosphere
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• v.26 no.4
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• pp.599-615
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• 2016

This study investigates the accuracy of short-term ocean predictions during the development of ocean stratification for the Korea Meteorological Administration (KMA) Global Seasonal Forecast System version 5 (GloSea5) as well as the effect of atmosphere-ocean coupling on the predictions through a series of sensitive numerical experiments. Model performance is evaluated using the marine meteorological buoys at seas around the Korean peninsular (KP), Tropical Atmosphere Ocean project (TAO) buoys over the tropical Pacific ocean, and ARGO floats data over the western North Pacific for boreal winter (February) and spring (May). Sensitive experiments are conducted using an ocean-atmosphere coupled model (i.e., GloSea5) and an uncoupled ocean model (Nucleus for European Modelling of the Ocean, NEMO) and their results are compared. The verification results revealed an overall good performance for the SST predictions over the tropical Pacific ocean and near the Korean marginal seas, in which the Root Mean Square Errors (RMSE) were $0.31{\sim}0.45^{\circ}C$ and $0.74{\sim}1.11^{\circ}C$ respectively, except oceanic front regions with large spatial and temporal SST variations (the maximum error reached up to $3^{\circ}C$). The sensitive numerical experiments showed that GloSea5 outperformed NEMO over the tropical Pacific in terms of bias and RMSE analysis, while NEMO outperformed GloSea5 near the KP regions. These results suggest that the atmosphere-ocean coupling substantially influences the short-term ocean forecast over the tropical Pacific, while other factors such as atmospheric forcing and the accuracy of simulated local current are more important than the coupling effect for the KP regions being far from tropics during the development of ocean stratification.

• KDI Journal of Economic Policy
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• v.35 no.4
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• pp.95-136
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• 2013

Using Workplace Panel Survey of 2005, 2007 and 2009 waves, this study estimates the effects of trade unions on employment and the proportion of irregular workers, short-term and part-time workers, and agent temporary and outsourced workers. While the estimation result shows that the percentage of hired workers increases under union presence, these results seem to be contaminated with bias because the differences between unionized firms before union establishment and non-unionized firms are not completely controlled even after adjusting for observed characteristics. Meanwhile, unionized firms and non-unionized firms with grievance procedures employ higher proportion of irregular workers. The proportion of short-term and part-time workers increases only when they are entitled to join trade unions. These imply that the rise in the percentage of irregular workers due to unions and grievance procedures is attributed to the increase in the percentage of agent temporary and outsourced workers. Also, when short-term and part-time workers are allowed to join the union, the firm replaces agent temporary and outsourced workers with short-term and part-time workers, so that the proportion of irregular workers do not change.

• Journal of Gastric Cancer
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• v.19 no.4
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• pp.438-450
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• 2019

Purpose: Although linear-shaped gastroduodenostomy (LSGD) was reported to be a feasible and reliable method of Billroth I anastomosis in patients undergoing totally laparoscopic distal gastrectomy (TLDG), the feasibility of LSGD for patients undergoing totally robotic distal gastrectomy (TRDG) has not been determined. This study compared the feasibility of LSGD in patients undergoing TRDG and TLDG. Materials and Methods: All c: onsecutive patients who underwent LSGD after distal gastrectomy for gastric cancer between January 2009 and December 2017 were analyzed retrospectively. Propensity score matching (PSM) analysis was performed to reduce the selection bias between TRDG and TLDG. Short-term outcomes, functional outcomes, learning curve, and risk factors for postoperative complications were analyzed. Results: This analysis included 414 patients, of whom 275 underwent laparoscopy and 139 underwent robotic surgery. PSM analysis showed that operation time was significantly longer (163.5 vs. 132.1 minutes, P<0.001) and postoperative hospital stay significantly shorter (6.2 vs. 7.5 days, P<0.003) in patients who underwent TRDG than in patients who underwent TLDG. Operation time was the independent risk factor for LSGD after intracorporeal gastroduodenostomy. Cumulative sum analysis showed no definitive turning point in the TRDG learning curve. Long-term endoscopic findings revealed similar results in the two groups, but bile reflux at 5 years showed significantly better improvement in the TLDG group than in the TRDG group (P=0.016). Conclusions: LSGD is feasible in TRDG, with short-term and long-term outcomes comparable to that in TLDG. LSGD may be a good option for intracorporeal Billroth I anastomosis in patients undergoing TRDG.

• Research in Community and Public Health Nursing
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• v.33 no.3
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• pp.340-355
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• 2022

Purpose: This study aimed to examine the effects of non-pharmacological sleep intervention programs in improving sleep quality among older adults in long-term care facilities. Methods: A literature search and selection was performed on nine different databases using the guidelines of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Overall, 14 studies met the inclusion criteria and were systematically reviewed. For the meta-analysis, the effect size was estimated using the random-effects model in Review Manager (RevMan) desktop version 5.4 of the Cochrane Library. Results: The meta-analysis of overall non-pharmacological interventions obtained a total effect size of 1.0 (standardized mean difference [SMD]=1.0, 95% confidence interval [CI]: 0.64~1.35), which was statistically significant (Z=5.55, p<.001). The most frequently studied non-pharmacological intervention was aroma therapy, with an effect size of 0.61 (SMD=0.61, 95% CI: 0.14~1.08), which was statistically significant (Z=2.55, p=.010). In the subgroup analysis, group-based interventions, interventions for >4 weeks, and untreated control studies were more effective. Conclusion: This study confirms that non-pharmacological interventions are effective in improving sleep quality among older adults in long-term care facilities. However, the sample size was small and the risk of bias in assessing the interventions of individual studies was unclear or high, thereby limiting the generalizability of the results. Further reviews that evaluate randomized control trials, evidence-based interventions that consider older adult participants' physical activity levels, different intervention methods and durations, and different control group intervention types are needed to obtain more conclusive evidence.

• Journal of Korea Water Resources Association
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• v.46 no.8
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• pp.833-842
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• 2013

The quantile mapping is utilized to reproduce reliable GCM(Global Climate Model) data by correct systematic biases included in the original data set. This scheme, in general, projects the Cumulative Distribution Function (CDF) of the underlying data set into the target CDF assuming that parameters of target distribution function is stationary. Therefore, the application of stationary quantile mapping for nonstationary long-term time series data of future precipitation scenario computed by GCM can show biased projection. In this research the Nonstationary Quantile Mapping (NSQM) scheme was suggested for bias correction of nonstationary long-term time series data. The proposed scheme uses the statistical parameters with nonstationary long-term trends. The Gamma distribution was assumed for the object and target probability distribution. As the climate change scenario, the 20C3M(baseline scenario) and SRES A2 scenario (projection scenario) of CGCM3.1/T63 model from CCCma (Canadian Centre for Climate modeling and analysis) were utilized. The precipitation data were collected from 10 rain gauge stations in the Han-river basin. In order to consider seasonal characteristics, the study was performed separately for the flood (June~October) and nonflood (November~May) seasons. The periods for baseline and projection scenario were set as 1973~2000 and 2011~2100, respectively. This study evaluated the performance of NSQM by experimenting various ways of setting parameters of target distribution. The projection scenarios were shown for 3 different periods of FF scenario (Foreseeable Future Scenario, 2011~2040 yr), MF scenario (Mid-term Future Scenario, 2041~2070 yr), LF scenario (Long-term Future Scenario, 2071~2100 yr). The trend test for the annual precipitation projection using NSQM shows 330.1 mm (25.2%), 564.5 mm (43.1%), and 634.3 mm (48.5%) increase for FF, MF, and LF scenarios, respectively. The application of stationary scheme shows overestimated projection for FF scenario and underestimated projection for LF scenario. This problem could be improved by applying nonstationary quantile mapping.

• 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 Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.174-179
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• 1999

In this paper, we propose an optimal algorithm for finding the shortest connection of two kinds of parts to pairs. If total part numbers are of size N, then there are order 2ㆍ(N/2)$^{N}$ possible solutions, of which we want the one that minimizes the energy function. The appropriate dynamic rule and parameters used in network are proposed by a new energy function which is minimized when 3-constraints are satisfied. This dynamic nile has three important parameters, an enhancement variable connected to pairs, a normalized distance term and a time variable. The enhancement variable connected to pairs have to a perfect connection of two kinds of parts to pairs. The normalized distance term get rids of a unstable states caused by the change of total part numbers. And the time variable removes the un-optimal connection in the case of distance constraint and the wrong or not connection of two kinds of parts to pairs. First of all, we review the theoretical basis for Hopfield model and present a new energy function. Then, the connection matrix and the offset bias created by a new energy function and used in dynamic nile are shown. Finally, we show examples through computer simulation with 20, 30 and 40 parts and discuss the stability and feasibility of the resultant solutions for the proposed connection algorithm.m.