• Journal of the Semiconductor & Display Technology
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• v.15 no.1
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• pp.47-51
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• 2016

Human visual system infers 3D vision through stereo disparity in the stereoscopic images, and stereo visioning are recently being used in consumer electronics which has resulted in much research in the application field. Basically, stereo vision system consists of four processes, which are cost computation, cost aggregation, disparity calculation, and disparity refinement. In this paper, we present and evaluate the existing various methods, focusing on cost aggregation for stereo vision system to comparatively analyze the performance of their algorithms for a given set of resources. Experiments show that Normalized Cross Correlation and Zero-Mean Normalized Cross Correlation provide higher accuracy, however they are computationally heavy for embedded system in the real time systems. Sum of Absolute Difference and Sum of Squared Difference are more suitable selection for embedded system, but they should be required on improvement to apply to the real world system.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.13.1-13.7
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• 2015

Background: This study evaluated Somatosensory evoked potentials (SEP), Quantitative sensory testing (QST), and thermography as diagnostic methods for nerve injury. Methods: From 2006 through 2011, 17 patients (mean age: 50.1 years) from ${\bigcirc}{\bigcirc}{\bigcirc}{\bigcirc}$ Hospital who sought care for altered sensation after dental implant treatment were identified. The mean time of objective assessment was 15.2 months after onset. Results: SEP of Inferior alveolar nerve(IAN) was $15.87{\pm}0.87ms$ on the normal side and $16.18{\pm}0.73ms$ on the abnormal side. There was delayed N20 latency on the abnormal side, but the difference was not statistically significant. In QST, the abnormal side showed significantly higher scores of the current perception threshold at 2 KHz, 250 Hz, and 5 Hz. The absolute temperature difference was $0.55^{\circ}C$ without statistically significance. Conclusion: These results indicate that QST is valuable as an objective method for assessment of nerve injury.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.1
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• pp.89-97
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• 2007

Simple regression models for pollutants load estimation of paddy developed by the Ministry of Environment in 1995 were tested with the data (T-N, T-P, $COD_{Mn}$, and SS) collected from Yeongsan and Seomjin river watersheds, and improvement measures were suggested. Overall, the simulated values showed a great difference from the measured values except for T-P according to the statistical analyses (RMSE, root mean square error; RMAE, root mean absolute error; RB, relative bias; EI, efficiency index). Such difference was assumed due to the fact that the models use only hydrologic factors (quantity factor) associated with precipitation and run-off as input parameters, but do not consider other factors which are likely to affect pollutant concentration (quality factor) including days after fertilization. In addition, in terms of accessibility of the models, some parameters in the models such as run-off depth and run-off amount which can not be obtained from the weather database but should be collected by on-site measurements need to be replaced with other variables.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.312-318
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• 2013

PURPOSE. The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS. A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of ${\alpha}$=.05. RESULTS. The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 ${\mu}m/m$ at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION. Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.

• Journal of Korea Water Resources Association
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• v.57 no.9
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• pp.615-626
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• 2024

To accurately and efficiently monitor soil moisture (SM) across South Korea, this study developed a SM estimation model that integrates the cloud computing platform Google Earth Engine (GEE) and Automated Machine Learning (AutoML). Various spatial information was utilized based on Terra MODIS (Moderate Resolution Imaging Spectroradiometer) and the global precipitation observation satellite GPM (Global Precipitation Measurement) to test optimal input data combinations. The results indicated that GPM-based accumulated dry-days, 5-day antecedent average precipitation, NDVI (Normalized Difference Vegetation Index), the sum of LST (Land Surface Temperature) acquired during nighttime and daytime, soil properties (sand and clay content, bulk density), terrain data (elevation and slope), and seasonal classification had high feature importance. After setting the objective function (Determination of coefficient, R² ; Root Mean Square Error, RMSE; Mean Absolute Percent Error, MAPE) using AutoML for the combination of the aforementioned data, a comparative evaluation of machine learning techniques was conducted. The results revealed that tree-based models exhibited high performance, with Random Forest demonstrating the best performance (R² : 0.72, RMSE: 2.70 vol%, MAPE: 0.14).

• Wind and Structures
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• v.19 no.5
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• pp.505-522
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• 2014

While effects of the atmospheric boundary layer flow on engineering infrastructure are more or less known, some local transient winds create difficulties for structures, traffic and human activities. Hence, further research is required to fully elucidate flow characteristics of some of those very unique local winds. In this study, important characteristics of observed vertical velocity profiles along the main wind direction for the gusty Bora wind blowing along the eastern Adriatic coast are presented. Commonly used empirical power-law and the logarithmic-law profiles are compared against unique 3-level high-frequency Bora measurements. The experimental data agree well with the power-law and logarithmic-law approximations. An interesting feature observed is a decrease in the power-law exponent and aerodynamic surface roughness length, and an increase in friction velocity with increasing Bora wind velocity. This indicates an urban-like velocity profile for smaller wind velocities and rural-like velocity profile for larger wind velocities, which is due to a stronger increase in absolute velocity at each of the heights observed as compared to the respective velocity gradient (difference in average velocity among two different heights). The trends observed are similar during both the day and night. The thermal stratification is near neutral due to a strong mechanical mixing. The differences in aerodynamic surface roughness length are negligible for different time averaging periods when using the median. For the friction velocity, the arithmetic mean proved to be independent of the time record length, while for the power-law exponent both the arithmetic mean and the median are not influenced by the time averaging period. Another issue is a large difference in aerodynamic surface roughness length when calculating using the arithmetic mean and the median. This indicates that the more robust median is a more suitable parameter to determine the aerodynamic surface roughness length than the arithmetic mean value. Variations in velocity profiles at the same site during different wind periods are interesting because, in the engineering community, it has been commonly accepted that the aerodynamic characteristics at a particular site remain the same during various wind regimes.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.69-74
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• 2013

In this paper, we propose the pattern classification algorithm of recognizing wrist movements based on electromyogram(EMG) to raise the recognition rate. We consider 30 characteristics of EMG signals wirh the root mean square(RMS) and the difference absolute standard deviation value(DASDV) for the extraction of precise features from EMG signals. To get the groups of each wrist movement, we estimated 2-dimension features. On this basis, we divide each group into two parts with mean to compare and promote the recognition rate of pattern classification effectively. For the motion classification based on EMG, the k-nearest neighbor(k-NN) is used. In this paper, the recognition rate is 92.59% and 0.84% higher than the study before.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.164-169
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• 2004

A spatial interpolation scheme incorporating local geographic potential for cold air accumulation (TOPSIM) was used to test the feasibility of operational frost warning in Chatancheon basin in Yeoncheon County, where the introduction of new crops including temperate zone fruits is planned. Air temperature from April to June 2003 was measured at one-minute intervals at four locations within the basin. Cold-air accumulation potentials (CAP) at 4 sites were calculated for 3 different catchment scales: a rectangular area of 65 x 55 km which covers the whole county, the KOWACO (Korea Water Corporation) hydrologic unit which includes all 4 sites, and the sub-basins delineated by a stream network analysis of the digital elevation model. Daily minimum temperatures at 4 sites were calculated by interpolating the perfect prognosis (i.e., synoptic observations at KMA Dongducheon station) based on TOPSIM with 3 different CAPs. Mean error, mean absolute error, and root mean square error were calculated for 45 days with no precipitation to test the model performance. For the 3 flat locations, little difference was detected in model performance among 3 catchment areas, but the best performance was found with the CAPs calculated for sub-basins at one site (Oksan) on complex terrain. When TOPSIM loaded with sub-basin CAPs was applied to Oksan to predict frost events during the fruit flowering period in 2004, the goodness of fit was sufficient for making an operational frost warning system for mountainous areas.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1102-1110
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• 2006

Sambyun(三變) is standard classification for nine palace. Through sambyun you can define new meaning of 'self' in three perspective ways. First 'self' could mean desire, emotion and memory which are ontological values. second, 'self' could mean id, ego, and superego which are practical values. Third 'self' could mean unconscious, preconscious and conscious which are epistemological values. Samjae(三才) is method that analyze things base on common features. Sa sang is method that analyze things base on difference. They both are device that searching for reason. If you put one's mind in center to observe the universe creativity of great absolute and symmetry distinction of yingyang produces jeung(情), supreme intelligence(神), and soul(魂魄). With these facts identity of the heaven(天), earth(地) and man(人) which is named samjae(三才) generates symbols of independent sasang(四象). And also, sasang generates relations between five element(五行), six energy(六氣). From ten shen(十神) relation comes seven feelings(七情) of man which creates a category of the eight trigrams(八卦) for divination and unification of nine palace(九宮). All these process are united.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.2
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• pp.21-27
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• 2000

In Fast motion estimaion algorithms, they reduce the computational complexity using the assumption that the matching error increases monotonically as the search moves away from the global minimum error In this paper, we first investigate the statistical characteristics of motion vector that the motion vector mostly occures on the side of small MAE (mean absolute error) between the reference search points when the MAE difference of them is large Therefore, we propose a fast motion estimation algorithm using this property and can reduce the number of search points The computer simulation result shows that the proposed method reduces computational complexity compared with conventional fast algorithms.