• Journal of The Korean Association For Science Education
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• v.41 no.5
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• pp.371-390
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• 2021

The purpose of this study is to develop a neuropsychological model for the spatial ability factor and to divide the brain active area involved in the light & shadow problem solving process into the domain-general ability and the domain-specific ability based on the neuropsychological model. Twenty-four male college students participated in the study to measure the synchronized eye movement and electroencephalograms (EEG) while they performed the spatial ability test and the light & shadow tasks. Neuropsychological model for the spatial ability factor and light & shadow problem solving process was developed by integrating the measurements of the participants' eye movements, brain activity areas, and the interview findings regarding their thoughts and strategies. The results of this study are as follows; first, the spatial visualization and mental rotation factors mainly required activation of the parietal lobe, and the spatial orientation factor required activation of the frontal lobe. Second, in the light & shadow problem solving process, participants use both their spatial ability as a domain-general thought, and the application of scientific principles as a domain-specific thought. The brain activity patterns resulting from a participants' inferring the shadow by parallel light source and inferring the shadow when the direction of the light changed were similar to the neuropsychological model for the spatial visualization factor. The brain activity pattern from inferring an object from its shadow by light from multiple directions was similar to the neuropsychological model for the spatial orientation factor. The brain activity pattern from inferring a shadow with a point source of light was similar to the neuropsychological model for the spatial visualization factor. In addition, when solving the light & shadow tasks, the brain's middle temporal gyrus, precentral gyrus, inferior frontal gyrus, middle frontal gyrus were additionally activated, which are responsible for deductive reasoning, working memory, and planning for action.

• Journal of the Korean earth science society
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• v.30 no.6
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• pp.721-733
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• 2009

A pattern of tropical cyclone (TC) movement in the western North Pacific area was studied using the empirical orthogonal function (EOF) and the best track data from 1951 to 2007. The independent variable used in this study was defined as the frequency of tropical cyclone passage in 5 by 5 degree grid. The $1^{st}$, $2^{nd}$ and $3^{rd}$ modes were the east-west, north-south and diagonal variation patterns. Based on the time series of each component, the signs of first and second mode changed in 1997 and 1991, respectively, which seems to be related to the fact that the passage frequency was higher in the South China Sea for 20 years before 1990s, and recent 20 years in the East Asian area. When the eigen vectors were negative values in the first and second modes and TC moves into the western North Pacific, TC was formed mainly at the east side relatively compared to the case of the positive eigen vectors. The first mode seems to relate to the pressure pattern at the south of Lake Baikal, the second mode the variation pattern around $30^{\circ}N$, and the third mode the pressure pattern around Japan. The first mode was also closely related to the ENSO and negatively related to the $Ni\tilde{n}o$-3.4 index in the correlation analysis with SST anomalies.

• Korean Journal of Cognitive Science
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• v.32 no.1
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• pp.1-53
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• 2021

The aim of this study was to analyze word frequency effects on eye fixation duration in Korean reading with a one-boundary diffusion model and to show how these phenomena differ between adults (20-28yrs) and adolescents (13-14yrs). We predicted that the drift rate parameter in the boundary diffusion model would reflect the information processing of the fovea during silent reading. Through an eye movement tracking experiment while controlling word properties such as the word frequency and the age of acquisition, Experiment 1 and Experiment 2 show that the information processing pertaining to words to be placed in the fovea is connected to the drift rate of the one-boundary diffusion model parameters. In Experiment 1,in the adult group, the mean difference in the fixation time in the response proportion between the presence of high-frequency condition and low-frequency condition in the adult group was higher in quantile 0.9 than it was in the 0.1 quantile, but in the adolescent group, the mean difference in the fixation time in the response proportion between the two conditions was not significantly in the 0.9 quartile.In Experiment 2, the mean difference in the fixation time in the response proportion between early-acquired condition and late-acquired condition in both groups was also higher in the quantile 0.9 than in the 0.1 quantile. The distribution of the two conditions in the both groups was positively skewed, and the difference showed the same pattern found in the results of Ratcliff(Ratcliff & McKoon, 2008). Based on the experimental results, we propose one-boundary diffusion model as a tool to explain word property effects and individual differences in reading. In particular, we suggest that the drift rate parameter in the boundary diffusion model reflects the information processing of the fovea during reading. In addition, the results show that one-boundary diffusion model can be used to predict the aforementioned phenomena in reading.

• Sleep Medicine and Psychophysiology
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• v.25 no.2
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• pp.51-57
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• 2018

Objectives: Previous studies have shown that periodic limb movements in sleep (PLMS) could be one of risk factors for cardiovascular morbidity. The purpose of this study was to investigate the association between PLMS and blood pressure changes during sleep. Methods: We analyzed data from 358 adults (176 men and 182 women) aged 18 years and older who were free from sleep apnea syndrome (Respiratory Disturbance Index < 5) and sleep disorders such as REM sleep behavior disorder or narcolepsy. Demographic characteristics, polysomnography records, and clinical variable data including blood pressure, body mass index, alcohol, smoking, and current medications were collected. In addition, self-report questionnaires including the Beck Depression Index, Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index were completed. Blood pressure change from bedtime to awakening was compared between the two periodic limb movement index (PLMI) groups [low PLMI ($PLMI{\leq}15$) and high PLMI (PLMI > 15)]. Blood pressure change patterns were compared using repeated measures analysis of variance. Results: Systolic blood pressure in the high PLMI group was lower than that in the low PLMI group (p = 0.036). These results were also significant when adjusted for gender and age, but were not statistically significant when adjusted for BMI, alcohol, smoking, anti-hypertension medication use and sleep efficiency (p = 0.098). Systolic blood pressure dropped by 9.7 mm Hg in the low PLMI group, and systolic blood pressure in the high PLMI group dropped by 2.9 mm Hg. There was a significant difference in delta systolic blood pressure after sleep between the two groups in women when adjusted for age, BMI, alcohol, smoking, antihypertensive medication use and sleep efficiency (p = 0.023). Conclusion: PLMS was significantly associated with a decreasing pattern in nocturnal BP during sleep, and this association remained significant in women when adjusted for age, BMI, alcohol, smoking, antihypertension medication use and sleep efficiency related to blood pressure. We suggest that PLMS may be associated with cardiovascular morbidity.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.1
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• pp.15-21
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• 2012

Purpose: Image Guided Radiation Therapy (IGRT) has been carried out using On-Board Imager system (OBI) in Asan Medical Center. For this reason, This study was to analyze and evaluate the impact on Cone-Beam CT according to variation of material and respiration. Materials and Methods: This study was to acquire and analyze Cone-Beam CT three times for two material: Cylider acryl (lung equvalent material, diameter 3 cm), Fiducial Marker (using clinic) under Motion Phantom able to adjust respiration pattern randomly was varying period, amplitude and baseline vis-a-vis reference respiration pattern. Results: First, According to a kind of material, when being showed 100% in the acryl and 120% in the Fiducial Marker under the condition of same movement of the motion phantom. Second, According to the respiratory alteration, when being showed 1.13 in the baseline shift 1.8 mm and 1.27 in the baseline shift 3.3 mm for acryl. when being showed 1.01 in 1 sec of period and 1.045 in 2.5 sec of period for acryl. When being showed 0.86 in 0.7 times the standard of amplitude and 1.43 in 1.7 times the standard of amplitude for acryl. when being showed 1.18 in the baseline shift 1.8 mm and 1.34 in the baseline shift 3.3 mm for Fiducial Marker. when being showed 1.0 in 1 sec of period and 1.0 in 2.5 sec of period for Fiducial Marker. When being showed 0.99 in 0.7 times the standard of amplitude and 1.66 in 1.7 times the standard of amplitude for Fiducial Marker. Conclusion: The effect of image size of CBCT was 20% in the case of Fiducial marker. The impact of changes in breathing pattern was minimum 13% - maximum 43% for Arcyl, min. 18% - max. 66% for Fiducial marker. This difference makes serious uncertainty. So, Must be stabilized breathing of patient before acquiring CBCT. also must be monitored breathing of patient in the middle of acquire. If you observe considerable change of breathing when acquiring CBCT. After Image Guided, must be need to check treatment site using fluoroscopy. If a change is too big, re-acquiring CBCT.

• PNF and Movement
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• v.19 no.3
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• pp.423-433
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• 2021

Purpose: Proprioceptive neuromuscular facilitation (PNF) is a method for promoting functional movements by facilitating neuromuscular responses through the stimulation of proprioceptors in the body using spiral and diagonal patterns. Irradiation, a basic principle of PNF, is a phenomenon in which the muscle activity of a body part caused by resistance is increased or spread into muscles in other parts via their connected muscles. Resistance training can be divided by body alignment into closed and open chain exercises. Methods: In this study, 19 healthy men in their 20s and 30s were selected as subjects. They performed PNF hip flexion, abduction, and internal rotation motions on their dominant side in an open chain exercise posture in which the nondominant sole was away from the wall, and in a closed chain exercise posture in which the sole was fixed to the wall. The nondominant leg's muscle activity was measured while resistance was maintained with applied pressure at 0%, 25%, 50%, 75%, and 100% of the maximum muscle strength in the last range of motions. A two-way analysis of variance (ANOVA) was conducted for a comparative analysis of the contralateral leg's muscle activity according to the chain exercise postures and the intensity of resistance intensity during PNF hip flexion, abduction, and internal rotation. In addition, an independent sample T-test was conducted for a comparative analysis of each chain exercise posture according to the intensity of resistance. A one-way ANOVA and a Scheffe post-hoc test were also performed to analyze the contralateral leg's muscle activity according to the intensity of resistance in the closed and open chain exercise postures. Results: Results of the two-way ANOVA found that the gluteus medius and the biceps femoris had statistically significant differences in both the chain exercise postures and resistance intensity (p<0.05), and that the vastus medialis and the gastrocnemius did not exhibit statistically significant differences in the chain exercise postures (p>0.05) but showed statistically significant differences in resistance intensity (p<0.05). As a result of the independent sample T-test, the application of the PNF hip flexion-abduction-internal rotation pattern led to a statistically significant difference in the contralateral gluteus medius during the closed chain exercise posture (p<0.05). According to the results of the one-way ANOVA and the Scheffe post-analysis, statistically significant differences were observed in the gluteus medius at 50%, biceps femoris at 75%, vastus medialis at 100%, and gastrocnemius at 100% during the closed chain exercise posture based on a resistance intensity of 0% (p<0.05). In the open chain exercise posture, statistically significant differences were found in the gluteus medius at 50%, biceps femoris at 50%, and vastus medialis at 75% based on the resistance intensity of 0% (p<0.05). In the same posture, there was no significant difference in the gastrocnemius's resistance intensity (p>0.05). Conclusion: When the PNF leg pattern is applied, each muscle requires effective chain exercise postures and resistance intensity to generate the contralateral leg muscle's irradiation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.848-857
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• 2018

Recently, around the world, active development of new renewable energy sources including solar power, waves, and fuel cells, etc. has taken place. Particularly, floating offshore wind farms have been developed for saving costs through large scale production, using high-quality wind power and minimizing noise damage in the ocean area. The development of floating wind farms requires an evaluation of the Maritime Safety Audit Scheme under the Maritime Safety Act in Korea. Floating wind farms shall be assessed by applying the line and area concept for systematic development, management and utilization of specified sea water. The development of appropriate evaluation methods and standards is also required. In this study, proper standards for marine traffic surveys and assessments were established and a systemic treatment was studied for assessing marine spatial area. First, a marine traffic data collector using AIS or radar was designed to conduct marine traffic surveys. In addition, assessment methods were proposed such as historical tracks, traffic density and marine traffic pattern analysis applying the line and area concept. Marine traffic density can be evaluated by spatial and temporal means, with an adjusted grid-cell scale. Marine traffic pattern analysis was proposed for assessing ship movement patterns for transit or work in sea areas. Finally, conceptual design of a Marine Traffic and Safety Assessment Solution (MaTSAS) was competed that can be analyzed automatically to collect and assess the marine traffic data. It could be possible to minimize inaccurate estimation due to human errors such as data omission or misprints through automated and systematic collection, analysis and retrieval of marine traffic data. This study could provides reliable assessment results, reflecting the line and area concept, according to sea area usage.

• Journal of Intelligence and Information Systems
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• v.26 no.2
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• pp.131-145
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• 2020

In line with the trend of industrial innovation, IoT technology utilized in a variety of fields is emerging as a key element in creation of new business models and the provision of user-friendly services through the combination of big data. The accumulated data from devices with the Internet-of-Things (IoT) is being used in many ways to build a convenience-based smart system as it can provide customized intelligent systems through user environment and pattern analysis. Recently, it has been applied to innovation in the public domain and has been using it for smart city and smart transportation, such as solving traffic and crime problems using CCTV. In particular, it is necessary to comprehensively consider the easiness of securing real-time service data and the stability of security when planning underground services or establishing movement amount control information system to enhance citizens' or commuters' convenience in circumstances with the congestion of public transportation such as subways, urban railways, etc. However, previous studies that utilize image data have limitations in reducing the performance of object detection under private issue and abnormal conditions. The IoT device-based sensor data used in this study is free from private issue because it does not require identification for individuals, and can be effectively utilized to build intelligent public services for unspecified people. Especially, sensor data stored by the IoT device need not be identified to an individual, and can be effectively utilized for constructing intelligent public services for many and unspecified people as data free form private issue. We utilize the IoT-based infrared sensor devices for an intelligent pedestrian tracking system in metro service which many people use on a daily basis and temperature data measured by sensors are therein transmitted in real time. The experimental environment for collecting data detected in real time from sensors was established for the equally-spaced midpoints of 4×4 upper parts in the ceiling of subway entrances where the actual movement amount of passengers is high, and it measured the temperature change for objects entering and leaving the detection spots. The measured data have gone through a preprocessing in which the reference values for 16 different areas are set and the difference values between the temperatures in 16 distinct areas and their reference values per unit of time are calculated. This corresponds to the methodology that maximizes movement within the detection area. In addition, the size of the data was increased by 10 times in order to more sensitively reflect the difference in temperature by area. For example, if the temperature data collected from the sensor at a given time were 28.5℃, the data analysis was conducted by changing the value to 285. As above, the data collected from sensors have the characteristics of time series data and image data with 4×4 resolution. Reflecting the characteristics of the measured, preprocessed data, we finally propose a hybrid algorithm that combines CNN in superior performance for image classification and LSTM, especially suitable for analyzing time series data, as referred to CNN-LSTM (Convolutional Neural Network-Long Short Term Memory). In the study, the CNN-LSTM algorithm is used to predict the number of passing persons in one of 4×4 detection areas. We verified the validation of the proposed model by taking performance comparison with other artificial intelligence algorithms such as Multi-Layer Perceptron (MLP), Long Short Term Memory (LSTM) and RNN-LSTM (Recurrent Neural Network-Long Short Term Memory). As a result of the experiment, proposed CNN-LSTM hybrid model compared to MLP, LSTM and RNN-LSTM has the best predictive performance. By utilizing the proposed devices and models, it is expected various metro services will be provided with no illegal issue about the personal information such as real-time monitoring of public transport facilities and emergency situation response services on the basis of congestion. However, the data have been collected by selecting one side of the entrances as the subject of analysis, and the data collected for a short period of time have been applied to the prediction. There exists the limitation that the verification of application in other environments needs to be carried out. In the future, it is expected that more reliability will be provided for the proposed model if experimental data is sufficiently collected in various environments or if learning data is further configured by measuring data in other sensors.

• The Korean Journal of Petroleum Geology
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• v.5 no.1_2 s.6
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• pp.36-47
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• 1997

This study presents multi-variable sequence model for a broader application of sequence concept proposed by Exxon group. The concept of the multi-variable model is based on the fact that internal organization and boundary type of the sequences are determined by three varying factors including 3rd-order cycles of eustasy, and tectonic movement and sediment influx with 2nd-order changes. Instead of Exxon group's systems tracts, this model adopts parasequence sets as the fundamental building blocks of the sequence, because they are descriptive stratigraphic units simply defined by internal stacking pattern, reflecting interactions of accommodation and sediment influx. Seven sequence types which vary in number and type of internal parasequence sets are formulated as associations of four types of accommodation development and three grades of sediment influx. In the southwestern margin of Ulleung Basin, the multi-variable sequence analysis of shelf-slope sequence shows systematic changes in stratal patterns and the numbs, of constituent parasequence sets (i.e. sequence type). These changes are interpreted to reflect temporal and spatial changes in type and rate of tectonic movement and sediment influx, as a result of back-arc opening and closing. During the back-arc opening, rapid subsidence, continuous rise of relative sea level, and high sediment influx gave rise to sequences dominantly of single progradational parasequence set. In the early stage of back-arc closing accompanied by local contractional deformation, different types of sequences contemporaneously formed depending on the spatial changes in tectonically-controlled accommodation and influx rates. During the subsequent slow back-arc subsidence, rise-dominated relative sea-level cycle was coupled with moderate to high sedimentation rate to have resulted in sequences consisting of $2~3$ parasequence sets.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.553-563
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• 2000

Horseshoe Expander is one of Slow Maxillary Expansion(SME) which aims to accommodate the contra- lateral expansion and midpalatal suture expansion or the palate. The appliance consists of skeleton type strew embedded in split Horseshoe appliance. It is the objectives of the presentation to manifest the changes in dental & craniofacial components subsequent to the application of Horseshoe Expander. The subjects for this study consisted of 32 patients (mean age : 12.7). frontal, lateral cephalometric headfilm were taken and study casts were fabricated before and after expansion. 24 items were measured, compared preexpansion with postexpansion. Especially, palatal volume was measured by means of 'Hydro-measurement method'. Tooth axis measurement on the dental casts were made with Universal bevel protractor, and Horseshoe Expander group were compared with RME group. This study of changes to maxillary expansion with Horseshoe Expander revealed the following significant results. 1. Triangular-shaped expansion pattern appeared in frontal cephalometric headfilm. 2. Palatal plane, occlusal plane, mandibular plane and upper incisor to FH increased in lateral cephalometrir headfilm. 3. Palatal volume increased significantly. A slight bite opening, reduction of occlusal contact points showed in dental casts. 4. A 2.2:1 ratio of the amount of intermolar width in maxilla(orthodontic movement) to maxillary width (orthopedic movement) was determined. 5. Horseshoe Expander group has less buccal tipping tendency than RME group, by taking high correlation coefficients in the upper second premolar and first molar. It was suggested that Horseshoe Expander showed less orthodontic changes, less buccal tipping tendency. In addition, it was effective in maxillary expansion.