• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6254-6259
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• 2015

On the optical system and the system itself of the noise of the noise from the outside always present. This noise is to function as reducing performance of the optical system. Therefore, the probability of error, thereby changing the system. In this paper, the error probability of the optical system due to changes in various values by introducing the characteristic variable the value of the optical system was calculated using the ${\kappa}$-square method. Was confirmed also in accordance with the calculation result is an error probability of the optical system changes, it was confirmed that when the value of the holding case for holding the standard about 400 Lux on the probability of the optical system. This case was found to be an optical system using a light source with a low output, so that means the smaller output is no problem to maintain the error probability value of the optical system is large. This means that more effective and less expensive to implement because it means that the optical system does not require the use of pre-amplifier for amplifying the signal at the receiving end of an optical system using a light source with a low output when the normal case.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.6
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• pp.535-544
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• 2018

Autonomous driving can be limited by only using sensors if the sensor is blocked by sudden changes in surrounding environments or large features such as heavy vehicles. In order to overcome the limitations, the precise road-map has been used additionally. This study was conducted to segment and classify road objects using 3D point cloud data acquired by terrestrial mobile mapping system provided by National Geographic Information Institute. For this study, the original 3D point cloud data were pre-processed and a filtering technique was selected to separate the ground and non-ground points. In addition, the road objects corresponding to the lanes, the street lights, the safety fences were initially segmented, and then the objects were classified using the support vector machine which is a kind of machine learning. For the training data for supervised classification, only the geometric elements and the height information using the eigenvalues extracted from the road objects were used. The overall accuracy of the classification results was 87% and the kappa coefficient was 0.795. It is expected that classification accuracy will be increased if various classification items are added not only geometric elements for classifying road objects in the future.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.3
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• pp.185-195
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• 2002

The purpose of this study is to evaluate and seek the best suitable band and threshold boundary level on the change detection of image differencing method using Landsat TM data(20 May 1987 and 20 May 1993) in Pyeongtaeg City. The change detection images differencing method were evaluated by using normal reference data with an optimal threshold level{$mean{\pm}(SD{\times}T$ value). The normal reference data consisted of positive change{change dark into light in image pattern, that is, it changed arable land(paddy, upland, forest and so on) to artificial area(buildings, vinyl-house and roads, etc)} and negative change(change light into dark in image pattern, that is, it changed artificial area into arable land). As the result, the kappa coefficients of visible bands(D1, D2 and D3) were higher than those of infrared bands(D4, D5 and D7), and than D1 image with 1.0 thresholding and normal reference data was a improved result in the land-surface change detection such as kappa coefficient : 68.4%, overall accuracy : 89.2%, negative change : 6.6%, positive change : 10.6%.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.52-60
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• 2003

Objectives: Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. The lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, utilization of simultaneous EEG and EOG processing and analyses to detect stage 1 sleep automatically were attempted. Methods: Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. A relative power of alpha waves less than 50% or relative power of theta waves more than 23% was regarded as stage 1 sleep. SEM(slow eye movement) was defined as the duration of both-eye movement ranging from 1.5 to 4 seconds, and was also regarded as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results were compared to the manual rating results done by two polysomnography experts. Results: A total of 169 epochs were analyzed. The agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3% and Cohen’s Kappa was 0.586 (p<0.01). A significant portion (32%) of automatically detected stage 1 sleep included SEM. Conclusion: Generally, digitally-scored sleep staging shows accuracy up to 70%. Considering potential difficulty in stage 1 sleep scoring, accuracy of 79.3% in this study seems to be strong enough. Simultaneous analysis of EOG differentiates this study from previous ones which mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnari remains a valid one in this study.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.383-389
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• 2005

Xerostomia is defined as a subjective complaint of dry mouth that may be perceived when there is insufficient mucosal wetting. However, the diagnosis and treatment of xerostomia is not that simple because of the fact that the subjective awareness of dry mouth is not always correlated with a diminution in the flow of saliva and there is always a difference between individuals in salivary flow rates needed for normal oral function. In the present study, the aim was to develop a questionnaire to evaluate the dry mouth symptoms and to analyze its reliability and usability as a diagnostic and analytic tool for xerostomia. The questionnaire which consists of 6 Visual Analogue Scale(VAS) type questions to evaluate the subjective oral dryness and 4 questions to evaluate behavior to avoid oral dryness was developed and administered twice with 1 week's interval to the healthy 88 young adults without dry mouth symptoms(44 males and 44 females; mean age was $25.6{\pm}3.1$ years in male and $24.3{\pm}2.1$ years in female). The results were as follows. 1 The intraclass correlation coefficients of 6 questions to evaluate the subjective oral dryness were as significantly high as 0.767 for the degree of oral dryness at other times of the day, 0.850 for the amount of saliva in the mouth, and 0.791 for the degree of effect on daily life due to oral dryness and as high as 0.563 for the degree of oral dryness at night or on awakening, 0.674 for the degree of oral dryness during eating, and 0.641 for the degree of difficulty in swallowing foods. 2. Cronbach's alpha value of 6 questions was 0.982. It can be concluded that the series of questions to evaluate the subjective oral dryness has high internal consistency. 3. Cohen's kappa values of 4 questions to evaluate behavior to relieve oral dryness were as significantly high as 0.850 for the frequency of keeping a glass of water at the bedside and as high as 0.506 the frequency of awakening during sleeping due to oral dryness, 0.419 for the frequency of sipping liquids to aid in eating dry foods, and 0.407 for the frequency of using a candy or chewing gum due to oral dryness. From the results, it can be concluded that the questionnaire consisting of 6 VAS type questions to evaluate the subjective oral dryness and 4 questions to evaluate behavior to relieve oral dryness has reliability of good to excellent level, and that the series of 6 VAS type questions has significantly high internal consistency to evaluate the subjective oral dryness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.62-70
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• 2016

This study investigated the development of a Korean version of the Ayurvedic constitution questionnaire and sought to verify its validity and reliability. Each study subject completed a self-administered questionnaire consisting of 63 questions. The Ayurvedic constitutions were placed into 7 categories. The results from 271 subjects revealed that the internal consistency reliability (Cronbach's ${\alpha}$) in the 41 item biometric signature part of the questionnaire was 0.757. The Cronbach's ${\alpha}$ for the 22 item psychological part was 0.616, whereas the Cronbach's ${\alpha}$ for the entire 63 items was 0.840. Taken together, the results indicate that the Korean version of the Ayurvedic questionnaire was valid. Within the questionnaire, the fourth item about body and the ninth item about psychological showed item-total correlations with negative total values, thereby indicating inconsistent (less reliable) responses. The remaining 61 items had a 0.864 degree of reliability. The results for the pure Vata Pitta and Kapha body types showed a high level of internal consistency reliability, presumably because those participants were of a pure constitution type. The Kappa factor for inter-item coincidence between the judgment of Ayurvedic constitution experts and the judgment derived from the written test scores was 0.619, thereby indicating questionnaire validity. The results of this study may be useful in further development of a Korean version of the Ayurveda constitution questionnaire.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.197-201
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• 2017

Most fishing vessels use an ice cooling system to manage and store captured fish. However, it is difficult to maintain an adequate temperature and salt concentration as well as operating time limitations in ice cooling systems. The purpose of this study is to investigate the heat transfer characteristics of flooded-type evaporators for a seawater cooling system to maintain proper seawater temperature in a fish tank. Experiments were conducted to investigate the heat transfer characteristics by changing the seawater temperature, flow rate, and saturation temperature of the refrigerant. It was confirmed that the heat transfer coefficient of an aluminum-brass tube was approximately 10% higher than that of a copper-nickel tube at the same heat flux. Furthermore, it was confirmed that applying the aluminum-brass tube to the heat transfer tube of a seawater heat exchanger was effective in terms of heat transfer. A comparison of the overall heat transfer coefficient of a single-tube heat exchanger and the flooded-type multi-tube heat exchanger for an 18-kW cooling system showed that the heat transfer coefficient of the single-tube heat exchanger was 25% higher under the same conditions. These results are considered to be important data for designing a flooded-type multi-tube heat exchanger.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.2
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• pp.120-132
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• 2009

Purpose: We diagnosed pediatric functional gastrointestinal disorders in Korean children and adolescents using Rome III criteria and investigated the clinical validity of QPGS-Rome III. Methods: Diagnosis based on QPGS was compared with the physician's diagnosis based on Rome III criteria. One hundred and thirty eight children and their parents completed the QPGS. Agreement rates were measured using Kappa method. Results: In physician's diagnoses, the most prevalent disorders were functional dyspepsia (39.1%), irritable bowel syndrome (38.4%), and functional abdominal pain (18.8%). Among QPGS based diagnoses, the most prevalent disorders were irritable bowel syndrome (39.1%), functional dyspepsia (29.7%), and functional abdominal pain (21.7%). The agreement rate was substantial (${\kappa}$=0.72, p=0.00). Diagnostic disagreements probably resulted from different patient responses to bowel movement form and bowel frequency. Conclusion: Functional dyspepsia, irritable bowel syndrome, and functional abdominal pain were the most common disorders by Rome III criteria in the Korean pediatric and adolescent patients. The agreement rate between physician's diagnoses and QPGS based diagnoses supported the validity of the QPGS-Rome III in Korean pediatric and adolescent patients. QPGS seems to be useful in diagnosis of patients with functional gastrointestinal disorders by Rome III criteria.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.395-432
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• 2021

Groundwater recharge rates vary widely by location and with time. They are difficult to measure directly and are thus often estimated using simulations. This study employed frequency and regression analysis and a classification and regression tree (CART) algorithm in a machine learning method to estimate groundwater recharge. CART algorithms are considered for the distribution of precipitation by subbasin (PCP), geomorphological data, indices of the relationship between vegetation and landuse, and soil type. The considered geomorphological data were digital elevaion model (DEM), surface slope (SLOP), surface aspect (ASPT), and indices were the perpendicular vegetation index (PVI), normalized difference vegetation index (NDVI), normalized difference tillage index (NDTI), normalized difference residue index (NDRI). The spatio-temperal distribution of groundwater recharge in the SWAT-MOD-FLOW program, was classified as group 4, run in R, sampled for random and a model trained its groundwater recharge was predicted by CART condidering modified PVI, NDVI, NDTI, NDRI, PCP, and geomorphological data. To assess inter-rater reliability for group 4 groundwater recharge, the Kappa coefficient and overall accuracy and confusion matrix using K-fold cross-validation were calculated. The model obtained a Kappa coefficient of 0.3-0.6 and an overall accuracy of 0.5-0.7, indicating that the proposed model for estimating groundwater recharge with respect to soil type and vegetation cover is quite reliable.

• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.107-119
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• 1996

To understand vegetation changes along environmental gradients in the natural forests in the east side of the Cascade Range in Washington state, USA, line transects were used to sample six different forest environments in the Wenatchee National Forest in the north-facing and south-facing sites at 975, 1280 and 1700m elevation. Data were analyzed using ordination by detranded correspondence analysis. Pseudotsuga menziesii was found as one of the dominant species on all the six sites regardless of elevation or aspect, while Pinus ponderosa was dominant on south slopes only. Abies grandis and A. lasiocarpa were dominant species on north slopes at elevations of 1280 and 1700m, respectively. Moisture, as it related to aspect, was identified as one of the most important environmental gradients for explaining the variation of vegetation types. On north-facing slopes, compared to south-facing slopes, where moisture was not as limiting and canopies could grow denser, probably, elevation or competitive interaction was more important. Species diversity tended to decrease with increasing environmental severity, with south slopes having less diversity than north slopes due to extended water stress and harsher temperature extremes on south slopes. The age structure on north-facing and south-facing slopes was different. Light intensity, moisture and climate were different between these two slopes. Large scale disturbances(e.g., big fire or insects) were major causes in changing age structure. Younger trees showed a closer relationship between size and age than adult trees. DBH values of shade intolerant species in south-facing slope were bigger than those of north-facing slope, which suggested that aspect of stands be the most important factor for age and size.