• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2443-2449
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• 2014

The recent increase in the number of network RTK users has led to a longer wait time for connecting to the existing VRS service, and consequently caused inconvenience such as a longer turnaround time for surveys. To resolve such issue, the NGII has developed the FKP service that involves a one-way communication. However, it is not spreading across the market as fast as anticipated, due to accuracy problems in the field. This study uses eight unified control points for a reliability assessment to compare and analyze the survey results obtained through the VRS and FKP services in various ways. The analysis reveals that the standard deviation of the FKP service is ${\pm}0.02m$, which is two times larger than that of the VRS, whilst its standard errors are X:-0.025m and Y:0.011m, proving that it is reliable to be used in the field. Therefore, we expect that the FKP service is going to be more broadly utilized for field surveys in the future.

• Journal of Biomedical Engineering Research
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• v.33 no.1
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• pp.25-31
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• 2012

The audio vision system was developed for visually impaired people and usability was verified. In this study ten normal volunteers were included in the subject group and their mean age was 28.8 years old. Male and female ratio was 7:3. The usability of audio vision system was verified by as follows. First, volunteers learned distance of obstacles and up-down discrimination. After learning of audio vision system, indoor and outdoor walking examination was performed. The test was scored by ability of up-down and lateral discrimination, distance recognition and walking without collision. Each parameter was scored by 1 to 5. The results were 93.5 +- SD(ranges, 86 to 100) of 100. In this study, we could convert visual information to auditory information by audio-vision system and verified possibility of applying to daily life for visually impaired people.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1262-1268
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• 2012

The present investigation was designed to determine whether supplementation of different level of vitamin E for 12 months to arsenic exposed goats (50 ppm as sodium arsenite) affords protection against the blood hemato-biochemical parameters caused by the metalloid. A total of 24 crossbred (Alpine${\times}$Beetal) lactating goats were assigned randomly into 4 equal groups (control, $T_1$, $T_2$ and $T_3$) of 6 in each, on the basis of average body weight ($36.10{\pm}0.11$ kg) and milk yield ($1.61{\pm}0.04$ kg/d). The animals in $T_1$, $T_2$ and $T_3$ were given 50 ppm arsenic, while in $T_2$ and $T_3$, additionally; vitamin E at the rate of 100 IU and 150 IU/kg dry matter (DM) respectively was additionally supplemented for the period of 12 months. Hemoglobin (Hb), total leukocyte (TLC) and blood lymphocyte % were decreased (p<0.05) in arsenic fed groups and vitamin E supplementation in the experimental group showed a protective potential. Significant increases (p<0.05) in aspertate transaminase (AST) and alanine transaminase (ALT) activities among arsenic supplemented groups were recorded, however vitamin E supplementation at higher doses showed a protective effect (p<0.05) against AST but in the case of ALT no ameliorating effect was found in either of the doses. Plasma total protein was decreased (p>0.05) but creatinine level was periodically increased in all As supplemented groups and vitamin E supplementation did not produce any protective effect. It can be concluded that arsenic exposure resulted in varying degree of changes in hemato-biochemical parameters and activities of antioxidant enzymes in goats but concomitant treatment with Vitamin E is partially helpful in reducing the burden of arsenic induced effect.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.21-30
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• 2020

In this paper, we predicted the propagation loss for the air-to-ground (A2G) channel between the ground control system and the unmanned aerial vehicle (UAV) using the prediction model for the aircraft recommended by the International Telecommunication Union (ITU). We analyzed the network coverage of the aerial relay system based on the medium altitude UAVs by expanding it into the air-to-air (A2A) channel. Climate and geographic factors in Korea were used to predict propagation loss due to atmospheres. We used the measured data published by the Telecommunication Technology Association (TTA) for regional rainfall-rate and effective earth radius factors to increase accuracy. In addition, the aerial relay communication system used the key parameter of the common data link (CDL) system developed in Korea recently. Prediction results show that the network coverage of the aerial relay system broadens at higher altitude.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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• pp.615-624
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• 2014

In this paper, we explore the electrical properties and high-frequency performance of carbon nanotube field-effect transistors (CNTFETs), based on the non-equilibrium Green's functions (NEGF) solved self - consistently with Poisson's equations. The calculated results show that CNTFETs exhibit superior performance compared with graphene nanoribbon field-effect transistors (GNRFETs), such as better control ability of the gate on the channel, higher drive current with lower subthreshold leakage current, and lower subthreshold-swing (SS). Due to larger band-structure-limited velocity in CNTFETs, ballistic CNTFETs present better high-frequency performance limit than that of Si MOSFETs. The parameter effects of CNTFETs are also investigated. In addition, to enhance the immunity against short - channel effects (SCE), hetero - material - gate CNTFETs (HMG-CNTFETs) have been proposed, and we present a detailed numerical simulation to analyze the performances of scaling down, and conclude that HMG-CNTFETs can meet the ITRS'10 requirements better than CNTs.

• Earthquakes and Structures
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• v.19 no.1
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• pp.17-28
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• 2020

In this paper, a modified and improved seismic isolation system called suspension columns for seismic isolation was investigated. An experimental study of the proposed isolation method, together with theoretical and numerical analyses, has thoroughly been conducted. In the proposed method, during the construction of the foundation, some cavities are created at the position of the columns inside the foundation and the columns are placed inside the cavities and hanged from the foundation by flexible cables rather being directly connected to the foundation. Since the columns are suspended and due to the gap between the columns and walls of the cavities, the structure is able to move freely to each side thus, the transmitted seismic actions are reduced. The main parameter of this isolation technique is the length of the suspension cable. As the cable length is changed, the natural frequency of the structure is also changed, thus, the desired frequency can be achieved by means of an appropriate cable length. As the experimental phase of the study, a steel frame structure with two floors was constructed and subjected to the acceleration of three earthquakes using a shaking table with different hanging cable lengths. The structural responses were recorded in terms of acceleration and relative displacement. The experimental results were compared to the theoretical and numerical ones, obtained from the MATLAB programming and the finite element software ABAQUS, showing a suitable agreement between them. The results confirm the effectiveness of the proposed isolation method in reducing the seismic effects on the structure.

• Journal of Drive and Control
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• v.13 no.4
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• pp.59-67
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• 2016

This paper proposes a model-prediction-based collision-avoidance algorithm for excavators for which the recursive-least-squares (RLS) estimation of the excavator's rotational inertia is used. To estimate the rotational inertia of the excavator, the RLS estimation with multiple forgetting and two updating rules for the nominal parameter and the forgetting factors was conducted based on the excavator-swing dynamics. The average value of the estimated rotational inertia that is for the minimizing effects of the estimation error was computed using the recursive-average method with forgetting. Based on the swing dynamics, the computed average of the rotational inertia, the damping coefficient for braking, and the excavator's braking angle were predicted, and the predicted braking angle was compared with the detected-object angle for a safety evaluation. The safety level defined in this study consists of the three levels safe, warning, and emergency braking. The analytical rotational-inertia-based performance evaluation of the designed estimation algorithm was conducted using a typical working scenario. The results of the safety evaluation show that the predictive safety-evaluation algorithm of the proposed model can evaluate the safety level of the excavator during its operation.

• Journal of Environmental Health Sciences
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• v.42 no.4
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• pp.280-292
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• 2016

Objectives: The objective of this study was to build COD regression models for the Han River and evaluate water quality. Methods: Water quality data sets for the dry season (as of January) during a four-year period (2012-2015) were collected from the database of the Han River automatic water quality monitoring stations. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR) were used to build five-descriptor COD models. Multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis (CA) are useful tools for extracting meaningful information. Results: The $r^2$ of the best COD models provided significant high values (> 0.8) between 2012 and 2015. Total organic carbon (TOC) was a surrogate indicator for COD (as COD/TOC) with high reliability ($r^2=0.63$ in 2012, $r^2=0.75$ for 2013, $r^2=0.79$ for 2014 and $r^2=0.85$ for 2015). The ratios of COD/TOC were calculated as 2.08 in 2012, 1.79 in 2013, 1.52 and 1.45 in 2015, indicating that biodegradability in the water body of the Han River was being sustained, thereby further improving water quality. The BOD/COD ratio supported these findings. The cluster analysis revealed higher annual levels of microorganisms and phosphorous at stations along the Hangang-Seoul and Hantangang areas. Nevertheless, the overall water quality over the last four years showed an observable trend toward continuous improvement. These findings also suggest that non-point pollution control strategies should consider the influence of upstreams and downstreams to protect water quality in the Han River. Conclusion: This data analysis procedure provided an efficient and comprehensive tool to interpret complex water quality data matrices. Results from a trend analysis provided much important information about sources and parameters for Han River water quality management.

• Atmosphere
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• v.25 no.1
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• pp.1-18
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• 2015

The most objective way to overcome the limitation of numerical weather prediction model is to represent the uncertainty of prediction by introducing probabilistic forecast. The uncertainty of the numerical weather prediction system developed due to the parameterization of unresolved scale motions and the energy losses from the sub-scale physical processes. In this study, we focused on the growth of model errors. We performed ensemble forecast to represent model uncertainty. By employing the multi-physics scheme (PHYS) and the stochastic kinetic energy backscatter scheme (SKEBS) in simulating typhoon Rusa (2002), we assessed the performance level of the two schemes. The both schemes produced better results than the control run did in the ensemble mean forecast of the track. The results using PHYS improved by 28% and those based on SKEBS did by 7%. Both of the ensemble mean errors of the both schemes increased rapidly at the forecast time 84 hrs. The both ensemble spreads increased gradually during integration. The results based on SKEBS represented model errors very well during the forecast time of 96 hrs. After the period, it produced an under-dispersive pattern. The simulation based on PHYS overestimated the ensemble mean error during integration and represented the real situation well at the forecast time of 120 hrs. The displacement speed of the typhoon based on PHYS was closest to the best track, especially after landfall. In the sensitivity tests of the model uncertainty of SKEBS, ensemble mean forecast was sensitive to the physics parameterization. By adjusting the forcing parameter of SKEBS, the default experiment improved in the ensemble spread, ensemble mean errors, and moving speed.

• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.7-14
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• 1996

A particle system is defined as a collection of primitive particles that together represent irregular and ever-changing objects such as smoke, clouds, waterfalls, and explosions. A particle system can be a powerful tool for modeling a deformable object's motion and change of form since it has dynamic properties with time. As an object becomes more complicated and shows more chaotic behavior, however, we need much more parameters for describing its characteristics completely. Consequently, the conventional particle system leads to difficulty in managing all of the parameters properly since one parameter can affect the others. Moreover, motion equations for representing particles' behavior are usually approximated to gain speed-ups. The inevitable errors in calculating the equations can cause an unexpected outcome. In this paper, we present a new approach of applying fuzzy contol to mage particles' motion and attributes changes over time. We also give an implementation result of a fuzzy particle system to show the feasibility of the proposed method. Applications of the system to explosions, nebulae, volcanos, and grass are presented.