• Journal of the Korean earth science society
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• v.29 no.6
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• pp.495-505
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• 2008

The main purposes of this study are to: (1) to develop astronomy observation program based on a standardized coefficient decision program; and (2) to apply the developed program to after-school or club activities. As a first step, we analyzed activities related to astronomy in the authorized textbooks that are currently adopted in high schools. based on the analysis, we developed an astronomy observation program according to the standardized coefficient decision program, and the program was applied to students' astronomical observations as part of the club activities. Specifically, this program used a 102 mm refracting telescope and digital camera. we took into account the observation site's environment of the urban areas in which many school were located and then developed a the computer program for observation activities. The results of this study are as follows. First, the current astronomical education in schools was based off of the textbooks. Specifically, it was mostly about analyzing the materials and making simulated experiments. Second, most schools participated in this study were located in urban areas where students had more difficulty in observation than in rural areas. Third, an exemplary method was investigated in order to make an astronomical observation efficiently in urban areas with the existing devices. In addition, the standardized coefficient decision program was developed to standardize the magnitude of stars according to the observed value. Finally, based on the students' observations, we found that there was no difference between the magnitude of a star in urban sites and in rural sites. The current astronomical education in schools lacks an activity of practical experiments, and many schools have not good observational sites because they are located in urban areas. However, use of this program makes it possible to collect significant data after a series of standardized corrections. In conclusion, this program not only helps schools to create an active astronomy observation activity in fields, but also promotes students to be more interested in astronomical observation through a series of field-based activities.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.43-50
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• 2000

Objectives: Obstructive sleep apnea syndrome(OSAS) is known to be associated with the changes of autonomic nervous system (ANS). Nasal continuous positive airway pressure(nCPAP) treatment was found to correct abnormal ANS changes in OSAS but it remains to be further clarified. We aimed to assess the effects of nCPAP on ANS manifested on electrocardiogram, using spectrum analysis in the subjects with OSAS. Methods: Digital polysomnography was performed in 18 patients with OSAS(mean age $43.7{\pm}16.6$ years ; 17 males, 1 female ; mean respiratory disturbance index (RDI) $48.6{\pm}20.9$) for one baseline and another CPAP nights. From each night, 300 continuous beats of ECGs without artifact were chosen from both stage 2 sleep and REM sleep and they were used for power spectrum analysis. We compared between baseline and CPAP nights the heart rate variability including VLF(very low frequency power), LF (low frequency power), HF(high frequency power), R-R means, R-R variance, and LF/HF ratio, using Wilcoxon signed ranks test. Results: In all patients, nCPAP proved to be effective in relieving apneas and snoring. During nCPAP night compared with baseline night, decreases in VLF(p<0.05), LF(p<0.01), and R-R variance(p<0.05) were found in stage 2 sleep, and decreased LF(p<0.05) was found in REM sleep. No significant differences in each sleep stage were found in other variables between the two nights. Conclusion: Our findings suggest that OSAS increases the activity of sympathetic nervous system and nCPAP application effectively decreases the activity. And nCPAP does not appear to influence the parasympathetic nervous activity in OSAS.

• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.105-112
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• 2014

Purpose: The aim of present investigation was to find out the influence of several times iatrogenic mobilization in the initial stage of implant installation on bone-implant osteointegration. Materials and methods: The experimental implants (3.75 mm in diameter, 8.0 mm in length) were made of commercially pure (Grade IV) titanium, and were treated with RBM ($MegaGen^{(R)}$: Ca-P) on lower 4.0 mm part. Only lower part of implant was inserted to bone and the implants were nonsubmerged. The 130 implants (two in each tibia) were inserted into the monocortical tibias of 33 rabbits which each weighed more than 3.5 kg (Female, New Zealand White). According to the removal torque interval, the groups were divided into 13 groups, group I (1 day), group II (1 day + 2 days), group III (1 day + 2 days + 3 days), group IV (1 day + 2 days + 3 days + 4 days), group V (2 days), group VI (2 days + 4 days), group VII (2 days + 4 days + 6 days), group VIII (2 days + 4 days + 6 days + 8 days), group IX (4 days), group X (4 days + 7 days), group XI (4 days + 7 days + 10 days), group XII (4 days + 7 days + 10 days + 14 days) and control group. In the control group, the removal torque was measured at 8 weeks with a digital torque gauge (Mark-10, USA). In the experimental groups, the removal torque was given once, twice, three times or four times by experiment design before the final removal torque and the value was measured each time. The implants were then screwed back to their original positions. All the experimental groups were given a final healing time of 8 weeks after placement, in which values were compared with the control groups and the 1st, 2nd, 3rd or 4th removal torque values in each experimental group. Results: In comparison of the final removal torque tests among experimental groups, the removal torque value of experimental groups except group XII were not statistically different that of control group. And the values of group I and II were significantly higher than the values of group VI, VIII, X, XI, and XII. In addition, the values of group III, IV, and V were significantly higher than group XI and XII. In comparison of the removal torque in the each experimental group, the final removal torque were significantly higher in all groups except group VIII, X, XI, and XII. Conclusion: If sufficient healing time was allowed, a few mobilization of fixture at the very early stage after the implant placement in the rabbits didn't interrupt the final bone to implant osseointegration.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.391-399
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• 2004

The purpose of this study was to compare curing efficiency of newly developed curing units to traditional halogen curing unit by measuring thermal change and surface microhardness according to curing light system. Materials and mathods : The types of curing units were traditional low intensity halogen light(Optilux 360), plasma arc light(Flipo), low heat plasma arc light(Aurys), low intensity LED(Starlight), and high intensity LED(Freelight2). Temperature at the tip of light guide was measured by a digital thermometer using K-type thermocouple. And after resin was filled to 2, 3, 4mm teflon mold, bottom temperature measured during curing. After 24 hours, microhardness of top surface and bottom surface of each resin specimen were measured. Results : The result of this study can be summarized as follows, 1. As measuring temperature of curing unit tips, Flipo is the highest as $52.4^{\circ}C,\;Freelight2(37.86^{\circ}C),\;Optilux360(32.68^{\circ}C),\;Aurys(32.34^{\circ}C),\;and\;Starlight(26.14^{\circ}C)$ were followed. 2. Flipo and Freelight2 were the highest similarly and Optilux360 and Aurys were similarly next and Starlight was lowest in temperature of bottom surface of resin mold. 3. Microhardness of top surface were generally similar, and Aurys was relatively low. 4. Optilux 360 and Freelight2 were the highest, and Flipo, Starlight, and Aurys were followed in microhardness of bottom surface. Conclusions : The results suggest that careful use of Flipo and Freelight2 might be able to cure greater depth of resin composite and do not cause thermal problems than other curing units.

• Korean Journal of Remote Sensing
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• v.36 no.5_2
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• pp.893-906
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• 2020

This paper reports on the analysis of the location accuracy of a precision image generation system manufactured for CAS 500. The planned launch date of the CAS 500 is 2021, and since it has not yet been launched, the analysis was performed using KOMPSAT-3A satellite images having similar specifications to the CAS 500. In this paper, we have checked the geolocation accuracy of initial sensor model, the model point geolocation accuracy of the precise sensor model, the geolocation accuracy of the precise sensor model using the check point, and the geolocation accuracy of the precise orthoimage using 30 images of the Korean Peninsula. In this study, the target geolocation accuracy is to have an RMSE within 2 pixels when an accurate ground control point is secured. As a result, it was confirmed that the geolocation accuracy of the precision sensor model using the checkpoint was about 1.85 pixels in South Korea and about 2.04 pixels in North Korea, and the geolocation accuracy of the precise orthoimage was about 1.15 m in South Korea and about 3.23 m in North Korea. Overall, it was confirmed that the accuracy of North Korea was low compared to that of South Korea, and this was confirmed to have affected the measured accuracy because the GCP (Ground Control Point) quality of the North Korea images was poor compared to that of South Korea. In addition, it was confirmed that the accuracy of the precision orthoimage was slightly lower than that of precision sensor medel, especially in North Korea. It was judged that this occurred from the error of the DTM (Digital Terrain Model) used for orthogonal correction. In addition to the causes suggested by this paper, additional studies should be conducted on factors that may affect the position accuracy.

• Progress in Medical Physics
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• v.18 no.2
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• pp.98-106
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• 2007

In June 2005, Yonsei University Medical Center, Severance Hospital upgraded a full-PACS system by adding twenty (5 mega pixels) Totoku ME511L flat panel LCD display devices for diagnostic interpretation purposes. Here we report upon the quantitative (or visual) acceptance testing of the twenty Totoku ME511L display devices for reflection, luminance response, luminance spatial dependency, resolution, noise, veiling glare, and display chromaticity based on AAPM TG 18 report. The tools used in the tests included a telescopic photometer, which was used as a colorimeter, illuminance meter, light sources for reflection assessment, light-blocking devices, and digital TG18 test patterns. For selected 8 flat panel displays, mean diffuse reflection coefficient ($R_d$) was $0.019{\pm}0.02sr^{-1}$. In the luminance response test, luminance ratio (LR), maximum luminance difference ($L_{max}$), and deviation of contrast response were $550{\pm}100,\;2.0{\pm}1.9%\;and\;5.8{\pm}1.8%$, respectively. In the luminance uniformity test, maximum luminance deviation was $14.3{\pm}5.5%$ for the 10% luminance of the TG18-UNL10 test pattern. In the resolution test with luminance measurement method, percent luminance (${\Dalta}L$) at the center was $0.94{\pm}0.64%$. In all cases of noise testing, rectangular target In every square in the three quadrants was visible and all 15 targets except the smallest one in the every corner pattern and the center pattern. The glare ratio (GR) was $12,346{\pm}1,995$. The color uniformity, (u',v'), was $0.0025{\pm}0.0008$. Also, the research results of qualify control guideline of primary disply devices suitable for domestic circumstance are presented All test results are in-line with the criteria recommended by AAPM TG18 report and are thus fully acceptable for diagnostic image interpretation. As a result, the acceptance testing schedule described provides not only an acceptance standard but also guidelines for quality control, optimized viewing conditions, and a means for determining the upgrading time of LCD display devices for diagnostic interpretation.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.77-81
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• 2014

Purpose : In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. Materials and Methods : In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made ??up to 5mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. Results : When there was the Optimold mask in the eyeball part, it was measured at $10.2cGy{\pm}1.5$ in the simulation therapy, and at $24.8cGy{\pm}2.7$ in the treatment, and when the Optimold mask was removed in the eye part, it was measured at $12.9cGy{\pm}2.2$ in the simulation therapy, and at $17.6cGy{\pm}1.5$ in the treatment. Conclusion : In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3 cGy in the simulation therapy and was reduced approximately 7 cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause cataracts and side effects was considered to be reduced due to decrease of the absorbed dose to the eye lens which had the high sensitivity on the radiation.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.145-152
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• 2012

Whenever pediatric dentists choose the preformed stainless steel crowns for restoration of primary molars, we usually prefer the crown forms that most fit to the abutment teeth. Despite some previous reports on significant ethnic difference in the size and shape of tooth crowns in primary dentition, only the imported products have been available to date, which might show some discrepancy with tooth anatomy of Korean. However, a domestic product of preformed stainless steel crown has been marketed recently that is expected to show more accurate fit to the primary tooth of Korean. To investigate the morphological characteristics of primary molars of Korean children, their mesiodistal and buccolingual diameters from the dental casts of 263 children in Pusan and Kyungsangnamdo province were measured by digital calipers. The measured data were compared with those of the three types of preformed stainless steel crowns(3M ESPE Stainless Steel Primary Molar Crown, Kids Crown, Sankin Anatom Primary Crown) by statistical processes with regression analysis. The results were as follows: 1. In every primary molar crown of three brands, the bucco-lingual width to mesio-distal width ratio (MD-BL ratio) showed higher values compared with those of natural teeth. 2. While the products of 3M ESPE and Shinhung showed similar features, those of Sankin showed some difference from both, and these difference was more marked in mandibular primary molars. 3. The nearer is the mesio-distal width of the crown to the average, the better was the adaptation of the preformed crown, and the reverse was true. 4. The teeth which revealed more discrepancy between preformed crown and natural tooth were upper and lower first primary molars.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.287-294
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• 2014

The purpose of this study is to use basic data of dental hygiene curriculum with a new technique called motivational interviewing of communication skill to demonstrate the effectiveness of the method of oral health care. In this study, we performed oral health care program that has been made in dental hygiene department to university students. It was assigned to the control group and 66 and 32 experimental group based on the date of the first visit time. It conducted motivational interviewing of a total of three times in the experimental group. The analytical results of the measurements obtained in the oral examination and questionnaires. The results were as follows: The experimental group measured value was reduced after the intervention compared to before the PSR to evaluate the state of periodontal, gingival index, calculus index, plaque control record (PCR; O'Leary plaque index), simple plaque scor of Quantitative Light Induced Fluorescnece Digital measurement value (p<0.05). Experimental group decreased more and more the result of changes in the reduction of the average of the PCR. But control group was reduced to 3 weeks and increased back to the middle 16 weeks. There was also support interaction between the measurement point and the groups (p<0.05). Re-visit adherence of fit, 12.1% in the control group, the experimental group was 43.7% in the period of participation in the oral health care program. Thus, visit adherence of the experimental group was higher. In this study, a group that has motivational interviewing, It was able to confirm the improvement of oral health state. Discussion of the motivational interviewing can be applied to oral health care program.