• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.15-19
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• 2019

In this study, Theta Gamma Coupling (TGC) analysis was carried out after performing simple and repeated upper limb exercise and comparative experiment to observe changes in the motor cortex of the brain through TGC and to see if mobile rehabilitation therapy is actually effective. As a result, exercise using mobile devices showed higher TGC values in motor cortex as compared with simple repeat upper limb exercise. In addition, paired t-test using SPSS showed statistically significant difference between exercise using mobile devices and simple repeat exercise at P3(t=3.390, df(degree of freedom)=12, p value=0.005). Exercise using mobile devices is effective for rehabilitation because it increases the Theta-Gamma Coupling and activates the motor cortex. Also, since the mobile game contents required the subject to detailed athletic ability adjustment with immersion in the task, it may be thought that brain activation is stronger than simple rehabilitation.

• Food Engineering Progress
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• v.21 no.1
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• pp.36-41
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• 2017

The release profiles of nisin from nisin-incorporating gel foods and the antimicrobial activities of the gels on the growth of Brochothrix thermosphacta in an aqueous system containing the gels have been investigated. A linear regression model was applied to determine the diffusion coefficient (D) for the diffusion of nisin in the gel. The antimicrobial activities of nisin released from 1, 2 and 3% (w/v) agar gels on the growth of B. thermosphacta in a broth medium with and without nisin were investigated. The D decreased from $1.2{\times}10^{-2}$ to $8.2{\times}10^{-3}$ and $6.4{\times}10^{-3}cm^2/s$ as the agar concentration in the gel increased from 1 to 2 and 3% (w/v), demonstrating the diffusion rate in the gels can be controlled by the agar concentration in gel. The agar gel incorporating nisin inhibited the B. thermosphacta growth in the broth medium by prolonging the lag phase. The growth inhibition was enhanced by the addition of nisin in the medium. The results of this study exhibited that the gel food is a feasible nisin delivery system with a controlled release achieved by the adjustment of agar concentration in the system, demonstrating the potential of nisin-incorporating gel for preserving particulate-containing drinks.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.639-640
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• 2015

Traditional construction planning based on historical data and heuristic adjustment can no longer incorporate all the operational details and guarantee the expected performance. The variation between the expected and the actual production leads to cost overruns or delay. Although predicting reliable productivity on construction site is getting more important, the difficulty of this increases. In this regard, this paper suggested to develop BIM-integrated simulation framework. This framework could predict productivity dynamics by considering factors affecting on construction productivity at operational phase. We developed the following processes; 1) enabling a BIM model to produce input data for simulation; 2) developing the construction operation simulation; 3) running simulation using BIM data and obtaining productivity results. The BIM-integrated simulation framework was tested with structural steel erection model because steel erection work is one of the most critical process influencing on the whole construction budget and duration. We could improve to predict more dynamic productivity from this framework, and this reliable productivity helps construction managers to optimize resource allocation, increase schedule reliability, save storage cost, and reduce material loss.

• Corrosion Science and Technology
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• v.22 no.6
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• pp.393-398
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• 2023

Properties of hafnium nitride (HfN) coatings are affected by deposition conditions, most often by the sputtering technique. Appropriate use of different magnetron sputtering modes allows control of the structural development of the film, thereby enabling adjustment of its properties. This study compared properties of HfN coatings deposited by direct current magnetron sputtering (dcMS), mid-frequency direct current magnetron sputtering (mfMS), and inductively coupled plasma-assisted magnetron sputtering (ICPMS) systems. The microstructure, crystalline, and mechanical properties of these HfN coatings were investigated by field emission electron microscopy, X-ray diffraction, atomic force microscopy, and nanoindentation measurements. HfN coatings deposited using ICPMS showed smooth and highly dense microstructures, whereas those deposited by dcMS showed rough and columnar structures. Crystalline structures of HfN coatings deposited using ICPMS showed a single δ-HfN phase, whereas those deposited using dcMS and mfMS showed a mixed δ-HfN and HfN_0.4 phases. Their performance were increased in the order of dcMS < mfMS < ICPMS, with ICPMS achieving a value of 47.0 GPa, surpassing previously reported results.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.1
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• pp.103-110
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• 2024

In this paper, a test bed for real-time network Real-Time Kinematic (RTK) research was constructed using reference stations of the NGII. A group of candidate station networks was derived, including three stations in Seoul. The group consisted of four stations with a distance of less than 100 km between them. Among several candidates, a network composed of stations with short distances between them and demonstrating good data quality for all reference stations was selected as the test bed. After collecting real-time data in Radio Technical Committee for Maritime services (RTCM) format from the selected stations and conducting a noise analysis on measurements, mm-level carrier phase measurement noise was confirmed. Afterwards, the user set the reference station inside the test bed and analyzed the network RTK positioning performance of the MAC method using the GPS L1 frequency as post-processing. From the result of the analysis it was confirmed that the residual error for all users was within 10 cm after applying the correction. Additionally, after determining integer ambiguities through Least-squares AMBiguity Decorrelation Adjustment (LAMBDA), it was confirmed that the fix rate was 100%, and all ambiguities were resolved as true values.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.15-25
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• 2012

The relationship between occlusion and periodontal health has been extensively studied. However, reports on the effects of passive eruption using occlusal reduction has not been sufficient. The purpose of the present randomized clinical trial was to assess the influence of passive eruption using occlusal reduction on the clinical periodontal parameters consisting of attachment level, pocket depth, tooth mobility, width of keratinized gingiva and osseous defect. The study was performed on 40 teeth of 16 subjects who have been treated for the moderate periodontitis at the Department of Periodontology, Pusan National University Hospital. At the baseline examination, after hygienic-phase and after 6 month from passive eruption using occlusal reduction, clinical parameters were monitored and radiographs were taken. The 20 teeth in the test group received passive eruption using occlusal reduction while the 20 control teeth did not receive any occlusal reduction. The results were as follows; 1) Degree of inflammation of periodontium was improved by initial therapy 2) Teeth received passive eruption using occlusal reduction demonstrated significantly greater reduction in pocket depth, tooth mobility and amount of bone loss, and increase in the width of keratinized gingiva, but no significant changes in the attachment level compared to the control teeth 3) There was significantly greater reduction in pocket depth, mobility, amount of bone loss and attachment level in the test teeth after initial hygienic phase when compared with baseline data. Taken together, these results suggest that the passive eruption using occlusal reduction would be helpful to improve periodontal health.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.761-768
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• 2010

This paper presents an effective method to achieve the wideband waveform for high resolution SAR(Synthetic Aperture Radar) using the frequency multiplication technique. And also this paper analyzes the root causes for the spectral regrowth due to 3rd-order intermodulation in chirp bandwidth expansion scheme using quadrature modulator and frequency multipliers. The amplitude and phase imbalance requirement are defined based on the simulation results in terms of quadrature channel imbalance. This minimizes the degradation of range resolution, peak sidelobe ratio and integrated sidelobe ratio. The wideband chirp generator using the frequency multiplier and memory map scheme was manufactured and the compensation technique was presented to reduce the spectral regrowth of SAR waveform by minimizing the amplitude and phase imbalance. After I and Q channel imbalance adjustment, the carrier level reduces －28.7 dBm to －53.4 dBm. Chirp signal with 150 MHz bandwidth at S-band expands to 600 MHz bandwidth at X-band. The sidelobe levels are reduced by about 8 to 9 dB by compensating the amplitude balance between I and Q channels.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.4
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• pp.401-406
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• 1992

Antifungal substances against three plant pathogenic fungi, Phytophthora capsici, Phytophthora nicotianae var. parasitica and Rhizoctionaia solani were fractionated cultures of Streptomyces sp. A-2 strain isolated in Korean soils. Characterizations of active substances related with antagonistic effects were follows : 1. The excellent media which showed the transfer efficiency of antagonistic substances from Streptomyces sp. A-2 strain G.Y.B and B.H.I. among four that are glucose yeast broth (G.Y.B), $M\ddot{u}eller$, brain heart infusion(B.H.I.) and Czapek media. Active substances which were transfered into ethylacetate or left in residual aqueous phase did not lose antagonistic activity in spite of autoclavation. This indicated that bonds of these compounds were rigid enough to keep activity under such conditions. 2. Antagonistic substances were extracted according to adjustment of pH 3 or pH12 to 5 day-old B.H.I. broth cultures of Streptomyces sp. A-2 strain. Comparative analysis fluorescent bands on HPTLC to antagonsitic spectra against three phytopathogenic fungi indicated that major substances with antagonistic activity were extracted regardless of different pH adjustment to broth cultures. Since UV spectrum of these fractions scanned from 500nm to 200nm was similiar to that of polyene macrolide, major substances related with antagonistic activities were assumed to be polyene derivatives antibiotics.

• Environmental Engineering Research
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• v.12 no.1
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• pp.16-20
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• 2007

Toxicity of metal plating wastewater was evaluated by using acute toxicity tests on Daphnia magna. To identify toxicants of metal plating wastewater, several manipulations such as solid phase extraction (SPE), ion exchange and graduated pH adjustment were used. The SPE test had no significant effect on baseline toxicity, suggesting absence of toxic non-polar organics in metal plating wastewater. However, anion exchange largely decreased the baseline toxicity by 88%, indicating the causative toxicants were inorganic anions. Considering high concentration of chromium in metal plating wastewater, it is thought the anion is Cr(VI) species. Graduated pH test showing independence of the toxicity on pH change strongly supports this assumption. However, as revealed by toxicity confirmation experiment, the initial toxicity of metal plating wastewater (24-h TU=435) was not explained only by Cr(VI) (24-h TU = 725 at $280\;mg\;L^{-1}$). Addition of nickel($29.5\;mg\;L^{-1}$) and copper ($26.5\;mg\;L^{-1}$) largely decreased the chromium toxicity up to 417 TU, indicating antagonistic interaction between heavy metals. This heavy metal interaction was successfully predicted by an equation of 24-h $TU\;=\;3.67\;{\times}\;\ln([Cu]\;+\;[Ni])\;+\;79.44$ at a fixed concentration of chromium.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.374-374
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• 2011

Recently the construction of railway sections passing the central area of cities and stations under railway lines are increasing, and then it is urgently required to take the countermeasures against the railway vibration and the second-phase noise radiated from it. The most efficient countermeasure, out of technologies developed up to now, is the floating slab track which is the track system isolated from the sub-structure by springs. In other countries, the source technologies for anti-vibration design and vibration isolator - one of key components - have been developed and many installation experiences have been accumulated. However, in Korea, since the system design technology and technologies for key components are not yet developed, the foreign system are being introduced without any adjustment, and the key component, vibration isolator, depends on imports. In this study, based on the results of previous studies of the dust-control device installation using the slab and go through time after lifting impressive when stepped on power generated by the cross-section of the slab and shear connection re-examined the structural stability.