• The korean journal of orthodontics
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• v.50 no.6
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• pp.373-382
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• 2020

Objective: To compare computer-aided design and computer-aided manufacturing (CAD/CAM) customized nitinol retainers with standard stainless-steel fixed retainers over a 12-month study period. Methods: This randomized controlled trial (RCT) was conducted on 62 patients randomly allocated to a control group that received stainless-steel retainers or a test group that received customized CAD/CAM nickel-titanium retainers. Four time points were defined: retainer placement (T0) and 1-month (T1), 6-month (T2), and 12-month (T3) follow-up appointments. At each time point, Little's irregularity index (LII) (primary endpoint) and dental stability measurements such as intercanine width were recorded in addition to assessment of periodontal parameters. Radiological measurements such as the incisor mandibular plane angle (IMPA) were recorded at T0 and T3. Failure events (wire integrity or debonding) were assessed at each time point. Results: From T0 to T3, LII and other dental measurements showed no significant differences between the two groups. The data for periodontal parameters remained stable over the study period, except for the gingival index, which was slightly, but significantly, higher in the test group at T3 (p = 0.039). The IMPA angle showed no intergroup difference. The two groups showed no significant difference in debonding events. Conclusions: This RCT conducted over a 12-month period demonstrated no significant difference between customized CAD/CAM nickel-titanium lingual retainers and standard stainless-steel lingual retainers in terms of dental anterior stability and retainer survival. Both retainers eventually appeared to be equally effective in maintaining periodontal health.

• Journal of Ginseng Research
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• v.42 no.1
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• pp.90-97
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• 2018

Background: Antihyperglycemic effects of Panax ginseng berry have never been explored in humans. The aims of this study were to assess the efficacy and safety of a 12-wk treatment with ginseng berry extract in participants with a fasting glucose level between 100 mg/dL and 140 mg/dL. Methods: This study was a 12-wk, randomized, double-blind, placebo-controlled clinical trial. A total of 72 participants were randomly allocated to two groups of either ginseng berry extract or placebo, and 63 participants completed the study. The parameters related to glucose metabolism were assessed. Results: Although the present study failed to show significant antihyperglycemic effects of ginseng berry extract on the parameters related to blood glucose and lipid metabolism in the total study population, it demonstrated that ginseng berry extract could significantly decrease serum concentration of fasting glucose by 3.7% (p = 0.035), postprandial glucose at 60 min during 75 g oral glucose tolerance test by 10.7% (p = 0.006), and the area under the curve for glucose by 7.7% (p = 0.024) in those with fasting glucose level of 110 mg/dL or higher, while the placebo group did not exhibit a statistically significant decrease. Safety profiles were not different between the two groups. Conclusion: The present study suggests that ginseng berry extract has the potential to improve glucose metabolism in human, especially in those with fasting glucose level of 110 mg/dL or higher. For a more meaningful benefit, further research in people with higher blood glucose levels is required.

• The Journal of Internal Korean Medicine
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• v.28 no.2
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• pp.346-353
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• 2007

Background : Over a thousand years of clinical preparation of Ephedrain traditional Korean medicine has confirmed effectiveness and security. Recently. Ephedra-containing herbal preparations to treat obesity are common. The aim of this study is to identify effects of Ephedra on psychological anxiety. Objectives : To determine effects of Ephedraon psychoactivity and autonomic nervous system. Methods : The study design was a double-blind randomized controlled trial. The subjects of this study were healthy adults. They were allocated to either the Ephedragroup (N =66) or the placebo group (N =32), Ephedra(8 g) or a placebo in similar opaque capsules was given twice a day for 2 weeks. Anxiety score was estimated with State-Trait Anxiety Inventory before first and after last medication. 36 of the Ephedragroup and 24 of the placebo group finished the trial and were analyzed. Paired samples T-test and independent samples T-test were applied to statistical analysis. Results : The following result was obtained: After taking Ephedra. state anxiety increased significantly. In the placebo group. both state and trait anxiety increased although significance was not reached. Conclusions : It is concluded that the intake of Ephedraplays a significant role in the increase of anxiety in healthy adults. It is suggested that anxiety level change should be considered when using Ephedra in clinics.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.318-320
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• 2018

When a ship sails on sea, it may be influenced by the environmental disturbance such as wind, wave, sea surface temperature, etc. These affect on the ship's speed, fuel consumption, safety and operating performance. It is necessary to find the optimal weather route of a ship to avoid adverse weather conditions which can put the crews in serious danger or cause structural damage to the vessel, machinery, and equipment. This study introduced how to apply A* algorithm based on sea trial test data for determining the optimal ship routes. The path cost function was modelled as a function of minimum arrival time or minimum energy depending on the time of various environment conditions. The specially modelled path-cost function and the safety constraints were applied to the A* algorithm in order to find the optimal path of the ship. The comparison of ship performances estimated by real sea trial's path and estimated optimal route during the voyage of the ship was investigated. The result of this study can be used to create a schedule to ensure safe operation of the ship with short passage time or minimum energy. In addition, the result of this study can be integrated into an on-board decision supporting expert system and displayed in Electronic Chart Display and Information System (ECDIS) to provide all the useful information to ship master.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.453-459
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• 2020

A sea trial of the speed performance test is the one of the most important means of verifying a ship's performance, and the International Organization for Standardization established a standard for this test in 2015. Environmental disturbances such as wind and waves are always present under real sea conditions, however, so it is impossible to accurately estimate delivered horsepower under ideal conditions. These disruptive influences also make it difficult to evaluate the positive effect of recently developed energy-saving devices. In this study, uncertainty analysis of improved speed performance was carried out using Monte Carlo simulation to confirm the energy-saving efficiency of a ship equipped with an air-lubrication system. The findings showed the average power saving to be 3.2%, with the expanded uncertainty of ± 2.7% at a 95% confidence level (k=2).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.259-269
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• 2019

The purpose of this study is to investigate the necessity and activation plan of trial work to increase the re-employment of injured industrial workers. This study applied an internet and paper questionnaire method to 1,058 employers listed in the Korea Workers' Compensation and Welfare Services. The employers were asked about their experiences with trial work and their preferences for supports. From September 2018, the survey was conducted for 6 weeks and a total of 201 questionnaires were analyzed. Descriptive analysis and t-tests were applied. The results of the study showed that the trial work system satisfied the employers who participated in it. In order for this system to operate smoothly for injured workers, it is necessary to simplify the system's procedures, increase the amount of the trial work subsidy, and improve the amount of support after the workers convert to full time employment. In order for employers to use the new system, $750 per month will be provided for 8 months when hiring one injured worker. Eighty percent of employers stated that they would hire injured workers if the subsidy and application period are accepted. Future study and suggestions for applying the trial work system for injured industrial workers are also discussed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.9-16
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• 2017

This study describes the development of a 1-inch cryogenic glove valve for an LNG pumping system and localization development achieved through the performance test. The cryogenic valve used in the LNG pumping system plays an important role in maintaining a flow rate by LNG transportation. This trial manufactured goods, which was achieved through reverse engineering and developing the assembly process. The result of the leak test satisfied the internal pressure condition using the 78-bar normal temperature test and maintained the anti-leakage condition. Also, the result of the cryogenic leak test (BS 6364: low temperature test procedure) maintained anti-leakage at -196 and 52 bar, which satisfied the test standards.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1557-1565
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• 2009

According to the GM/RT2141, to assess the safety of vehicle, the validated the vehicle dynamic model should be applied. The validation of the vehicle model is against the static test, some kind of vehicle type test results have been used to determine the suspension characteristics and the vehicle dynamic characteristics. To validate the vehicle model and the test results, first the test results has been analysed as to specified the suspension characteristics and than the parameters to related with the test result has to be adjusted to show the same results of the test. In this process the parameters of vehicle model have been determined to show the coherence of the two results of the simulation and the test by trial & error. In this report, the optimization tool has been introduced in this model validation process and shows the efficient and well validated model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1554-1558
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• 2012

Method development and validation of ellagic acid for the standardization of Gochang Bokbunja as a functional ingredient and health food were accomplished. A Symmetry$^{(R)}$ (C18, $4.6{\times}250mm$, $5.0{\mu}m$) column was used with a gradient elution system of 1% formic acid in water and acetonitrile. This method was validated according to specificity, linearity, accuracy, precision test, and recovery test. Specificity was confirmed with identical retention time, and calibration curves of ellagic acid showed good linear regression ($R^2$ >0.9996). Relative standard deviations (RSD) of data from the intra- and inter-day experiments were less than 2.28% and 2.84%, except in the low limit of quality control (LLOQ, $1{\mu}g/mL$) sample. The results of the recovery test were from 89.17% to 97.92% with RSD values from 0.05 to 0.14%. Therefore, we performed analysis of ellagic acid as a marker compound in Gochang Bokbunja extracts. The amount of ellagic acid in Gochang Bukbunja was about $1.918{\mu}g/mg$ (0.192%) in the three times analysis, and RSD was less than 2.36% by the validated method. These results suggest that the developed HPLC method is simple, efficient, and could contribute to the quality control of Gochang Bokbunja extract as a functional ingredient.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.298-306
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• 2014

The railway signalling system for safe train operation regulates the train speed to ensure the safety distance between consecutive trains by using wayside facilities such as track circuits and interlocking systems. In addition, this signalling system controls the trackside equipment such as a railway point along the train line. This ground-equipment-based train control systems require high CAPEX and OPEX. To deal with these problems, the train control system using the on-board controller has been recently proposed and its related technologies have been widely studied. The on-board-controller-based train control system is that the on-board controller can directly control the trackside equipment on the train line. In addition, if this system is used, the wayside facilities can be simplified, and as a result, the efficient and cost-effective train control system can be realized. To this end, we have developed the prototypes of the on-board controller and wayside object control units which control the point and crossing gate and performed the integrated operation simulation in a testbed. In this paper, before the field test of the on-board-controller-based train control system, we perform the preliminary field trial including the installation test, wireless access test, interface test with other on-board devices, and normal operation test.