• Journal of Bio-Environment Control
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• v.10 no.4
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• pp.251-257
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• 2001

This experiment was conducted to investigate the effect of chitosan on the growth and yield of fall-planted potatoes. The research was carried out in fall-planted potatoes from August 2000 to Aprial 2001 at the height of 250m above sea level in Jeju Island. Soaking for 30 min. of seed potatoes in 200 times diluted solution of 3% liquid chitosan shortened days to emergence by 4 to 6 days. Stem length, number of stems and number of stolons per plant were 56.5 cm, 4.3, and 19.0, respectively, when seed potatoes were soaked for 30 min. in 200 times diluted solution of 3% liquid chitossan. Total potato yield in this treatment reached 2,963 kg per 10a and was significantly greater than in other treatments. Yield of marketable tubers (greater than 30g) per 10a for treatment of seed potatoes soaking in 200 times diluted solution of 3% liquid chitosan and for treatment of foliage spray with 200 times diluted solution of 3% liquid chitosan plus chitosna power (10 kg per 10a) miximg with soil was 2,761 kg and 2,628 kg, respectively. Contents of Mg, Fe and B were the greatest in the treatment of 30 min. soaking of seed potatoes in 200 times diluted solution of 3% liquid chitosanm. The increased contents of these elements are considered to have caused yield increase as a result of increased chlorophyll content for photosynthesis.

• Journal of Music and Human Behavior
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• v.12 no.1
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• pp.1-21
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• 2015

This study examined the effects of a tablet PC-based music-making program on the executive function of adolescents with intellectual disabilities. Four adolescents with intellectual disabilities participated in this program. Each participant received 45-minute individual sessions twice a week for a total of 16 sessions. The music-making program was designed in the sequence of planning; learning table PC operations; exploring musical elements; making rhythm, melody, and lyrics; composing loop sections; and presentation of the completed music. The Stroop test, Children's Color Trails Test, and Digit Span and Letter-Number sequencing tests were measured at pretest, midtest, and posttest in order to examine changes in executive function. The participants showed increased scores on all three tests. The participants' attention span also increased and their attempts to correct errors during tasks occurred more frequently at posttest. This study supports the effects of the technology-based program on the executive function of adolescents with intellectual disabilities and presents its expanded applicability for adolescents who show low cognitive function and limited motivation for cognitive engagement.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.1-11
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• 2019

The purpose of this study is to examine the effects of different group incentive type on performance under two types of interdependence in a task structure. One hundred twenty college and graduate students were recruited and asked to perform group typing task. Each typing groups organized three members. Participants were randomly assigned to one of four experimental conditions: equally-distributed incentive and differentially-distributed under two different task interdependence. In this study, the dependent variable was the number of correctly typed characters. We found the significant interaction effects between group incentive type and task interdependence. Specifically, under interdependent task, the work performance of participants in equally-distributed group incentive condition was higher than the performance in differentially-distributed group incentive condition.

• The Journal of the Korea Contents Association
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• v.12 no.7
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• pp.261-272
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• 2012

This study was conducted so as to examine which change tDCS (Transcranial Direct Current Stimulation) for improving working memory can make on the EEC of stroke patients. Among the patients who suffered for more than 6 months by hemiparalysis caused by stroke, 20 patients selected by MMSE and DST were randomly divided into I group (10 patients) fulfilled by only CCT and II group (10 patients) fulfilled by both tDCS and CCT for total 4 weeks, 30 minutes per a day, three times per a week. For examining EEC variation, the absolute spectrum power was calculated by three bands (${\theta}$; 4~8 Hz, lower ${\alpha}$; 8~10.5 Hz, upper ${\alpha}$;10.5~13 Hz) during the task of words, photos and mental calculation with EEC test, before the arbitration, after 2 weeks and after 4 weeks, so the rate of increase and decrease (%) for the reference EEC was obtained. As the results, the first, particular aspects different one another in three bands were detected according to the measuring period and task. The second, in the forth week, there was only a significant difference in lower ${\alpha}$-power of all tasks. Therefore, through the procedure measuring EEC of this study, the degree of working memory's damage can be expressed by numerical value and tDCS should be additionally helpful for brain damaged patients' perception rehabilitation.

• Neonatal Medicine
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• v.18 no.2
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• pp.353-358
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• 2011

Purpose: The goal of this study was to compare the efficacy of oral 25% dextrose treatment or/and pacifier for analgesia in healthy newborns during intramuscular injection of a hepatitis B vaccine. Methods: A prospective, randomized, partially blinded, clinical trial was performed in 132 healthy newborns. They were assigned randomly to 4 treatment groups: control group (2 mL distilled water), dextrose group (2 mL 25% dextrose), pacifier group, dextrose+pacifier group (pacifier coating with 25% dextrose) during intramuscular injection of hepatitis B vaccine. For all groups, Neonatal Infant Pain Scale (NIPS), Neonatal Facial Coding System (NFCS), Premature Infant Pain Profile (PIPP) scores were evaluated before the injection, during the injection, and at 2 minutes after the injection. Pain scores were compared among the 4 groups. Results: Maternal and neonatal characteristics were similar among the 4 groups. 25% dextrose treatment led to lower NIPS pain scores during injection (6.4${\pm}$0.9 vs. 5.5${\pm}$1.7, P=0.01) and after injection (1.6${\pm}$2.0 vs. 0.6${\pm}$0.9, P=0.01) and NFCS pain scores after injection (1.5${\pm}$2.3 vs. 0.7${\pm}$0.8, P=0.04) than control group. The number of neonates who feel the pain (indication of scores: NIPS${\geq}$4, NFCS${\geq}$3) decreased (9 (23.1%) vs. 0 (0%), P=0.04 via NIPS, 7 (17.9%) vs. 0 (0%), P=0.02 via NFCS). However, all treatment groups did not decreased PIPP scores, compared with the control group. Conclusion: Oral 25% dextrose is effective than distilled water or using pacifier with or without 25% dextrose in reducing pain during intramuscular injection of hepatitis B vaccinations. Further study based on this preliminary study need about nonpharmacologic management of pain in newborns.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.51-59
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• 2000

Objectives: It is been reported that sleep patterns change significantly during the adolescent years. In Korea, the sleep patterns of adolescents have not been investigated systematically. The authors performed preliminary study about sleep patterns of middle and high school students in Seoul before nationwide study. Methods: The authors selected one of middle and high schools located in typical middle class area in Seoul. The study was performed during the periods when examination or vacation did not affect the sleep cycle. Fifty to one hundred male and female students were selected from one school year each. One of investigators explained the purposes and methods of this study to the students and gave additional explanation to the teachers in charge. We designed a questionnaire for subjects to describe the nap time, bedtime, sleep latency, total sleep time, rise time and sleep efficiency, and the students recorded sleep logs for seven days including weekend. Eight hundred three students answered the questionnaires. Among them, we selected the subjects who recorded sleep logs at least three days and filled up the questionnaires completely. Finally, seven hundred seventy one subjects were included in this study. Weekend was defined as the time from Saturday morning to Sunday morning, and Sunday sleep patterns were treated separately. Results: Across the six school years, school-night bedtimes were delayed one hundred twenty four minutes and school-ight rise times were advanced by thirty five minutes. School-night total sleep times were decreased by one hundred fifty eight minutes, and weekend bedtimes were delayed by one hundred twenty five minutes. The students tended to oversleep on weekends, and the mean of weekend oversleep was ninety six minutes. But, bedtime in weekends was not delayed. Daytime sleep, sleep latency and sleep efficiency were not changed greatly across six school years. Total sleep time of female students was decreased significantly between third middle school year and first high school year, but time of male students was decreased between first and second high school year. Conclusion: It is supposed that sleep deficiency of middle and high school students in Seoul was due to delayed bedtimes and advanced rise times across the school years.

• Progress in Medical Physics
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• v.9 no.1
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• pp.11-21
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• 1998

Circular metal electrodes were vacuum-deposited with chromium on the both sides of Teflon-FEP and PET film characteristic of electret and the physical properties of the two polymers were observed during an irradiation by gamma-ray from $\^$60/Co. With the onset of irradiation of output 25.0 cGy/min the induced current increased rapidly for 2 sec, reached a maximum, and subsequently decreased. A steady-state induced current was reached about in 60 second. The dielectric constant and conductivity of Teflon-FEP were changed from 2.15 to 18.0 and from l${\times}$l0$\^$-17/ to 1.57${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/, respectively. For PET the dielectric constant was changed from 3 to 18.3 and the conductivity from 10$\^$-17/ to 1.65${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/. The increase of the radiation-induced steady state current I$\^$c/, permittivity $\varepsilon$ and conductivity $\sigma$ with output(4.0 cGy/min, 8.5 cGy/min, 15.6 cGy/min, 19.3 cGy/min) was observed. A series of independent measurements were also performed to evaluate reproducibility and revealed less than 1% deviation in a day and 3% deviation in a long term. Charge and current showed the dependence on the interval between measurements, the smaller the interval was, the bigger the difference between initial reading and next reading was. At least in 20 minutes of next reading reached an initial value. It may indicate that the polymers were exhibiting an electret state for a while. These results can be explained by the internal polarization associated with the production of electron-hole pairs by secondary electrons, the change of conductivity and the equilibrium due to recombination etc. Heating to the sample made the reading value increase in a short time, it may be interpreted that the internal polarization was released due to heating and it contributed the number of charge carriers to increase when the samples was again irradiated. The linearity and reproducibility of the samples with the applied voltage and absorbed dose and a large amount of charge measured per unit volume compared with the other chambers give the feasibility of a radiation detector and make it possible to reduce the volume of a detector.

• Journal of Intelligence and Information Systems
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• v.16 no.3
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• pp.77-97
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• 2010

Market timing is an investment strategy which is used for obtaining excessive return from financial market. In general, detection of market timing means determining when to buy and sell to get excess return from trading. In many market timing systems, trading rules have been used as an engine to generate signals for trade. On the other hand, some researchers proposed the rough set analysis as a proper tool for market timing because it does not generate a signal for trade when the pattern of the market is uncertain by using the control function. The data for the rough set analysis should be discretized of numeric value because the rough set only accepts categorical data for analysis. Discretization searches for proper "cuts" for numeric data that determine intervals. All values that lie within each interval are transformed into same value. In general, there are four methods for data discretization in rough set analysis including equal frequency scaling, expert's knowledge-based discretization, minimum entropy scaling, and na$\ddot{i}$ve and Boolean reasoning-based discretization. Equal frequency scaling fixes a number of intervals and examines the histogram of each variable, then determines cuts so that approximately the same number of samples fall into each of the intervals. Expert's knowledge-based discretization determines cuts according to knowledge of domain experts through literature review or interview with experts. Minimum entropy scaling implements the algorithm based on recursively partitioning the value set of each variable so that a local measure of entropy is optimized. Na$\ddot{i}$ve and Booleanreasoning-based discretization searches categorical values by using Na$\ddot{i}$ve scaling the data, then finds the optimized dicretization thresholds through Boolean reasoning. Although the rough set analysis is promising for market timing, there is little research on the impact of the various data discretization methods on performance from trading using the rough set analysis. In this study, we compare stock market timing models using rough set analysis with various data discretization methods. The research data used in this study are the KOSPI 200 from May 1996 to October 1998. KOSPI 200 is the underlying index of the KOSPI 200 futures which is the first derivative instrument in the Korean stock market. The KOSPI 200 is a market value weighted index which consists of 200 stocks selected by criteria on liquidity and their status in corresponding industry including manufacturing, construction, communication, electricity and gas, distribution and services, and financing. The total number of samples is 660 trading days. In addition, this study uses popular technical indicators as independent variables. The experimental results show that the most profitable method for the training sample is the na$\ddot{i}$ve and Boolean reasoning but the expert's knowledge-based discretization is the most profitable method for the validation sample. In addition, the expert's knowledge-based discretization produced robust performance for both of training and validation sample. We also compared rough set analysis and decision tree. This study experimented C4.5 for the comparison purpose. The results show that rough set analysis with expert's knowledge-based discretization produced more profitable rules than C4.5.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.255-261
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• 2016

The purpose of this study was to investigate the relationship between excessive daytime sleepiness (EDS) and blood pressure (BP) in patients with obstructive sleep apnea-hypopnea (OSAH). Patients were classified into four groups based on their severity of polysomnographic data: the snoring group (n=108)-characterized by Apnea-Hypopnea Index (AHI<5); the mild OSA group (n=186)-AHI $5{\leq}AHI$<15; the moderate OSA group (n=179)- AHI $15{\leq}AHI$<30; and the severe OSA group (n=233)-$AHI{\geq}30$. On the same night of polysomnography (PSG), BP levels were measured before sleeping (bedtime BP) and immediately after waking up on the following morning (morning BP). EDS was recognized as ESS (epworth sleepiness scale)${\geq}9$. The differences and correlations between BP and PSG parameters in the EDS and non-EDS groups of OSAH patients were analyzed. MAP was positively correlated with BMI, AHI, and total arousal (r=0.099, r=0.142, r=0.135, p<0.01, p<0.01, p<0.01), while negatively correlated with mean $SaO_2$ (r=-0.258, p<0.01). The EDS group had overall younger population ($47.2{\pm}11.3$ vs $50.3{\pm}11.4$, p=0.023), higher DBP (both bedtime and morning, $83.1{\pm}9.7$ vs $81.4{\pm}8.8$ and $86.4{\pm}9.2$ vs $83.6{\pm}9.7$)(p=0.031, p=0.047), and higher SBP (both bedtime and morning, $126.7{\pm}11.2$ vs $123.4{\pm}12.4$, $128.9{\pm}12.4$ vs $125.3{\pm}12.9$)(p=0.021, p=0.021) than compared with the non-EDS group. In hypertensive OSAH patients, patients with EDS were also younger and had higher total arousal number, as well as higher morning and bedtime DBP and SBP than compared with the non-EDS group (p<0.005, p=0.008, p<0.001 and p<0.001). EDS in OSAHS patients is a special phenotype characterized by younger age, higher DBP, more severe desaturation, and hypertension.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.65-74
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• 2011

Purpose: In this study we investigated improvement degree of reading ability of the student who was in a condition of dyslexia symptoms by wearing $ChromaGen^{TM}$ lenses. Methods: After wearing the $ChromaGen^{TM}$ lens for 3 months, the dyslexia symptoms corrective lens, 52 students who had suspected symptom of dyslexia were asked questions, and we measured the improvement degree of reading ability of the student. Results: The $ChromaGen^{TM}$ wearer read 110.26${\pm}$22.07 words in 1 minute, and naked yeses or glass wearing students read 106.42${\pm}$22.70 words. Reading ability of the student having suspected symptom of dyslexia were measured after wearing $ChromaGen^{TM}$ for 3 months. The results showed improvement reading ability of 3.70${\pm}$0.29 (p=0.01, t=2.26), 4.50%${\pm}$0.10 (p=0.01, t=2.78) for $ChromaGen^{TM}$ wearer with statistical difference. A survey on the satisfaction of reading improvement with wearing $ChromaGen^{TM}$ showed that 88.4% of questioned person answered wearing $ChromaGen^{TM}$ had improved their dyslexia symptoms. Conclusions: With statisical significance (p<0.05). this study suggests that $ChromaGen^{TM}$ lens has an effect on improving reading speed of dyslexia patient. We know from these results that the $ChromaGen^{TM}$ lens which is used to dyslexia had an effect to improvement of reading speed for dyslexia. And the results of this study is statistically different (p<0.05).