• Journal of Educational Research in Mathematics
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• v.17 no.1
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• pp.1-31
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• 2007

Negative numbers have been one of the most difficult mathematical concepts, and it was only 200 years ago that they were recognized as a real object of mathematics by mathematicians. It was because it took more than 1500 years for human beings to overcome the quantitative notion of numbers and recognize the formality in negative numbers. Understanding negative numbers as formal ones resulted from the Copernican conversion in mathematical way of thinking. we first investigated the historic and the genetic process of the concept of negative numbers. Second, we analyzed the conceptual fields of negative numbers in the aspect of the additive and multiplicative structure. Third, we inquired into the levels of thinking on the concept of negative numbers on the basis of the historical and the psychological analysis in order to understand the formal concept of negative numbers. Fourth, we analyzed Korean mathematics textbooks on the basis of the thinking levels of the concept of negative numbers. Fifth, we investigated and analysed the levels of students' understanding of the concept of negative numbers. Sixth, we analyzed the symbolizing process in the development of mathematical concept. Futhermore, we tried to show a concrete way to teach the formality of the negative numbers concepts on the basis of such theoretical analyses.

• Journal of Korean Public Health Nursing
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• v.21 no.1
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• pp.37-45
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• 2007

Purpose: A diverse range of measurement methods to evaluate the effect of smoking is more powerful than using a single measure. The objectives of this study were to examine the relationships among smoking pack year, self-reported smoking dependence, and urinary cotinine levels, and to investigate the psychological variables in working men. Method: In this cross-sectional study, we surveyed men working in an electronic company who participated in a smoking cessation program. Among 57 men who completed questionnaires, 25 participate in a test for cotinine levels. Results: Smoking pack year was significantly and positively correlated with the FTND-K (Korean version of Fagerstrom test for nicotine dependence) sum scores (r=0.631, p=0.000) and with the levels of urine cotinine (r=0.463, p=0.023). The relationship between FTND-K sum scores and urinary cotinine levels was also significantly positive (r=0.639, p=0.001). Those with higher social support, especially family support, tended to perceive a higher self-efficacy to smoking cessation. Conclusion: These findings suggest that self-reported smoking pack year and nicotine dependence in working men may be a valid way to evaluate the effect of smoking. A supportive family may influence smoking cessation in working men as it increases self-efficacy to avoid smoking.

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.376-383
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• 2012

A number of scientific researches are currently being conducted on the potential health hazards of power frequency electric and magnetic field (EMF). There exists a non-objective and psychological belief that they are harmful, although no scientific and objective proof of such exists. This possible health risk from ELF magnetic field (MF) exposure, especially for children under 17 years of age, is currently one of Korea's most highly contested social issues. Therefore, to assess the magnetic field exposure levels of those children in their general living environments, the personal MF exposure levels of 436 subjects were measured for about 6 years using government funding. Using the measured database, estimation formulas were developed to predict personal MF exposure levels. These formulas can serve as valuable tools in estimating 24-hour personal MF exposure levels without directly measuring the exposure. Three types of estimation formulas were developed by applying evolutionary computation methods such as genetic algorithm (GA) and genetic programming (GP). After tuning the database, the final three formulas with the smallest estimation error were selected, where the target estimation error was approximately 0.03 ${\mu}T$. The seven parameters of each of these three formulas are gender (G), age (A), house type (H), house size (HS), distance between the subject's residence and a power line (RD), power line voltage class (KV), and the usage conditions of electric appliances (RULE).

• Archives of Pharmacal Research
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• v.29 no.7
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• pp.566-569
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• 2006

This study examined whether or not acute stress is linked to increases in the neurosteroid levels, which is a well-known neurotransmitters associated with stress stimuli. The ginsenoside, Rb1, was tested in order to better understand its potential effects on altering the neurosteroid levels and ultimately attenuating stress. The optimal stressed condition was checked by measuring the 5a-dihydroprogesterone (DHP) and allopregnanolone (THP) levels in the brain after immobilization stress at various times. Based on this result, an acute stress model was set up to give 30 min of immobilization stress. The DHP and THP brain levels of the stressed mice were then investigated after administering Rb1 orally (10 mg/kg). These results were compared with the neurosteroid level in the stressed mice not given Rb1. Saline was administered orally to the nonstressed mice to check the placebo effect. Acute immobilization stress induced an increase in the THP and DHP concentration in the frontal cortex and cerebellum. When Rb1 was administered orally prior to immobilization stress, the THP level in the frontal cortex and cerebellum was significantly lower than that in the stressed animals not given Rb1. On the other hand, the DHP level was lower in the cerebellum only. This suggests that the metabolism of the brain neurosteroids is linked to psychological stress, and Rb1 attenuates the stressinduced increase in neurosteroids.

• Journal of Ginseng Research
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• v.43 no.3
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• pp.402-407
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• 2019

Background: To investigate the neurobiological evidence supporting the adaptogenic effects of Korean Red Ginseng in reducing the harmful consequences of stress using a double-blind, placebo-controlled trial. Method: Sixty-three subjects with high stress levels were randomized to receive an orally administered, double-blind, 6-week treatment with Korean Red Ginseng (n = 32) or placebo (n = 31). All participants underwent a comprehensive psychological evaluation using Beck Depression Inventory and Stress Response Inventory, cognitive evaluation using the continuous performance test, biological evaluation by measuring blood levels of lipids, catecholamines, inflammation markers, and heart rate variability at baseline and after 6 weeks. Results: At baseline, both groups showed no significant differences in age, sex, years of education, Beck Depression Inventory, and Stress Response Inventory. After 6 weeks, triglyceride levels were significantly increased within the normal limit in the Korean Red Ginseng group (F = 4.11, p = 0.048), and the epinephrine level was decreased in this group (F = 4,35, p = 0.043). The triglyceride increase was significantly associated with epinephrine decrease (B = 0.087, p = 0.041), suggesting that Korean Red Ginseng may stabilize the sympathetic nervous system. In addition, we detected a significant group by time effect in the visually controlled continuous performance test, suggesting positive effects of Korean Red Ginseng on cognition. Conclusion: Korean Red Ginseng might help to stabilize the sympathetic nervous system and improve cognition in individuals with high stress.

• Korean Journal of Psychosomatic Medicine
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• v.22 no.1
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• pp.23-30
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• 2014

Objectives : Homocysteine has been associated with cognitive impairment and various psychiatric symptoms. This study was designed to examine the relationship exists between plasma homocysteine concentration and behavioral and psychological symptoms of dementia(BPSD). Methods : 41 subjects with dementia of Alzheimer's type were included in this study. We carried out history taking, physical examination, and cognitive assessment for the diagnosis of dementia of Alzheimer's type based on DSM-IV. We scored the Mini Mental State Examination(MMSE), Global Deterioration Scale(GDS), Clinical Dementia Rating(CDR), and the Korean Neuropsychiatric Inventory(K-NPI). We also measured levels of homocysteine, folate, and vitamin $B_{12}$ in the plasma. Results : We found statistically significant positive correlations between homocysteine concentration with NPI total score, and with scores of several sub-domains such as delusion, agitation/aggression, depression/dysphoria, and elation/euphoria. No significant correlation existed between homocysteine levels and scores of MMSE, GDS, and CDR. Conclusions : This study shows that plasma homocysteine levels are associated with BPSD. Further research is necessary to identify pathophysiologic mechanisms underlying these relationships.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.215-222
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• 2017

The study aimed to determine the characteristics of human brains and to identify the students' aptitude and interests by developing and applying the program for recognizing students' desired future careers. A total of 135 students (59 elementary school children and 76 middle school adolescents) were surveyed for 2 days and 1 night. The study conclusions are as follows. First, the program proved effective in forming the constructive recognition for their future jobs because they could explore careers in the future and because they could raise their consciousness of perspectives on careers. Second, the program makes it possible to explore future jobs that are appropriate to them based on their aptitude and interests and to enhance their career competencies. Further research is required because more consideration is needed. First, the present research applied the same program to all student participants despite the differences in developmental levels. Therefore, future research needs to involve elements that reflect their distinct psychological proficiency levels. Second, to show the evidence of the effectiveness, further studies need to focus on diverse dependent variables that may influence the results other than their distinct psychological proficiency levels.

• Journal of The Korea Institute of Healthcare Architecture
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• v.24 no.1
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• pp.41-49
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• 2018

Purpose: It is recently reported that the increasing noise in the hospitals has caused psychological and physiological stress problems with patients, and medical staffs. This study intends to investigate and analyze the noise levels in the sub stations in comparison with those in the wards in general. This study tries also to find some alterative solutions to the immediate problems. Methods: Noise measurements are conducted in advance prior to analyzing their results at two general hospitals with more than 900 beds, in the comprehensive nursing service wards and in the main/ sub stations located in the general wards Results: Although the noise level in the comprehensive nursing service wards has been slightly lower than that in the general wards, this result is over the recommended noise levels. Therefore it is recommended that efforts should be made to low down the noise level as an alternative and to replace the aged carts as well. Implications: The comprehensive nursing service wards are required to take measures against the various noise sources.

• Korean Journal of Child Studies
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• v.37 no.4
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• pp.129-143
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• 2016

Objective: This study aimed to examine the mediating effects of internalized shame and rejection sensitivity in the relationship between covert narcissism and displaced aggression in late childhood. Methods: The participants included 1,060 children (grades 5 and 6; 547 boys and 513 girls) from four elementary schools located in Seoul, Gyeonggi-do, and Chungcheong-do. Results: The primary results of this study were as follows. First, child covert narcissism had a direct effect on displaced aggression; children who perceived higher levels of covert narcissism exhibited more displaced aggression. Second, child covert narcissism had an indirect effect on their displaced aggression through internalized shame and rejection sensitivity. Children who perceived higher levels of covert narcissism reported more internalized shame and rejection sensitivity, which led to more displaced aggression. Conclusion: The findings of this research indicate that individual and interpersonal psychological factors need to be considered to explain displaced child aggression. Further, it is important that we help children to gain positive relationships with family and peers. It will help them break away their negative self or others representation, especially their internalized shame and rejection sensitivity.

• Journal of Korean Academy of Nursing
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• v.47 no.2
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• pp.233-241
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• 2017

Purpose: The purpose of this study was to examine the effects of parental stress, social support, and coping behavior on burnout among mothers caring for children with cerebral palsy. Methods: Participants in this cross-sectional, descriptive study were 185 mothers who completed a self-report structured questionnaire. The data were analyzed using descriptive statistics, t-test, one-way ANOVA, correlation and multiple linear regression analyses with IBM SPSS Win 22 program. Results: Parental stress and coping behavior were strong predictors of burnout among mothers of children with cerebral palsy. These variables explained 50.0% of the variance in burnout. Social support was not a predictor of burnout. A higher level of burnout was associated with higher levels of parental stress and lower levels of social support and coping behavior. Conclusion: Mothers of children with cerebral palsy are vulnerable to burnout. These results show that effective strategies for reducing parental stress and improving positive coping behavior are needed to reduce burnout in these mothers.