• Journal of radiological science and technology
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• v.26 no.2
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• pp.57-61
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• 2003

The purpose of this study is to compare both 1.5T and 4.7T in Praietal White matter material Phantom using the same methodology at both field strengths. Data at both field strengths are compared in terms of $T_2$ relaxation times, line widths and SNRs MR imaging and $^1H$ MR spectroscopy were performed on GE 1.5T SIGNA system and Broker Biospec 4.7T/30 MRI/MRS system. After phantom axial scan $^1H$ MRS was obtained from T2 weighted image by 3-dimensional localization technique(PRESS : Point RE solved spectroscopy Sequence) this phantom is composed of an aqueous solution 36.7 mmol/L of NAA, 25.0 mmol/L of Cr, 6.3 mmol/L of choline chloride, 30.0 mmol/L or Glu, and 22.5 mmol/L of MI(adjusted to a pH of 7,15 in a phosphate buffet). Data processed using software developed inhouse. At 1.5T, T2 relaxation times for Cho, Cr, and NAA were $0.41{\pm}0.07,\;0.26{\pm}0.04,\;0.46{\pm}0.07$ while at 4.7T they were $0.17{\pm}0.03,\;0.14{\pm}0.05,\;0.20{\pm}0.03$ respectively. At 1.5T, line widths for water, Cho, Cr and NAA were $2.9{\pm}0.7,\;1.6{\pm}0.7,\;1.7{\pm}0.8,\;2.2{\pm}0.02Hz$ while at 4.7T they were $5.2{\pm}1.1,\;4.6{\pm}1.9,\;4.01{\pm}1.8,\;4.8{\pm}1.9Hz$ respectively. It can be seen that $T_2$ relaxation times were significantly shorter at 4.7 compared to 1.5T and that the line widths were also broader. The average SNRs for NAA for subjects at short and long TEs were $23.5{\pm}11.3$ at TE=20 msec ; $15.4{\pm}7.7$ at TE=272 msec at 1.5T and $40{\pm}8.3$ and $17{\pm}3.5$ respectively at 4.7T higher field strength is superior because of improved sensitivity and chemical shift dispersion. However these improvements are partially offset by increased line widths and decrease $T_2$ relaxation times, which act to reduce both sensitivity and resolution. In our experiments with the equipment available to us, 4.7T proton spectra at short TEs exhibit moderately improved sensitivity compared to 1.5T.

• The Journal of Korean Society for School & Community Health Education
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• v.9 no.2
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• pp.15-31
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• 2008

Objective: This study is a quasi-experimental study by nonequivalent control group pretest-posttest design, performed in order to identify whether the program developed on the basis of Ajzen(1988, 1991)'s theory of planned behavior (TPB) for predicting the safety behavior of students of department of dental technology affects intention toward safety behavior and general behavior. Therefore, the purpose of this study is to identify whether the safety education in laboratories in which knowledge is reinforced on the basis of the TPB theory affects safety behavior. Methodology: The theoretical framework of this study was established on the basis of the TPB by Ajzen(1988, 1991). This study was performed between May 20 and December 5, 2006, and the subjects included 101 in the experimental group and 98 in the control group, a total of 199. The experimental group was educated through six 50-minute sessions (twice a week) for three weeks. The experimental group was pretested, educated, and then asked to answer the pro-questionnaire after finishing the sixth session, but the control group was free from intervention. The research tool in this study was developed by the authors with reference to the process of tool development used in Schifter and Ajzen (1985) based on Ajzen and Fishbein(1980)'s tool development guide. Results: The data were analyzed through SPSS 14.0 version. The reliability test of attitude, subjective norm, perceived norm, intention, and behavior toward safety behavior as TPB variables was calculated of Cronbach's alpha coefficient, and general characteristics and the homogeneity test of the experimental and the control groups were analyzed through t test and $X^2$ test. According to the results of the analysis, the experiment group may be higher than the control group after the safety education in the scores of attitude, the subjective norm, the perceived norm, and the intention toward safety behavior as TPB independent variables showed no significant difference, but there was significant difference in the behavior and the knowledge. Meanwhile, according to the results of the pretest and posttest, eleven items in the experimental group and two items in the control group showed significant difference in the behaviors, and twelve in the former and four in the latter were significantly different in the knowledge. Conclusion: The safety education program developed on the basis of TPB was identified to enhance safety behavior and knowledge. Therefore, the safety education program used in this study for students of department of dental technology may be utilized as database for safety education in the department of dental technology.

• Journal of Korean Academy of Nursing
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• v.26 no.1
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• pp.223-247
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• 1996

This study was done to provide information which would lead to nursing care of the elderly being more holistically through an understanding of the phenomena of powerlessness based on the lived experience of powerlessness by the elderly, the meaning the elderly give to such phenomena, and what essence of powerlessness is. The methodology used in this study was Max Van Manen's phenomenological method based on the philosophy of Merleu-Ponty and a concerted approach was realized through the 11 steps suggested in the Van Manen's method. Data collection was done from March 2, 1995 to December 30, 1995. The subjects for this study were four elderly persons who lived with their families and who were over 60 years of age. Data were collected about the lived experience of the elderly, this researcher's experience of powerlessness, the linguistic meaning of powerlessness, idioms of the word or a feeling of powerlessness, and descriptions of powerlessness in the elderly as they appeared in the literature, are works, and phenomenological literature. All data were used to provide insights into the phenomena of powerlessness. Data about the experience of powerlessness by the elderly were collected through open interviews, participation, and observation. In the analysis of the theme of this study, the aspects of the theme, powerlessness in the elderly were clarified, thereby abstracting and finding meaningful statements by the elderly about their feeling of powerlessness, and then those significant statements were expressed as linguistic transformations. The summarized findings from the study are as follows : 1. Five meanings of powerlessness in the elderly were defined. 〈weakness〉, 〈dependence〉, 〈frustration〉, 〈worthlessness〉 and 〈giving up〉. 2. 〈Weakness〉 means that the elderly experience, not only their aging but also, their becoming weak and the loss of physical function frequently caused by diseases. 〈Dependence〉 means that the elderly experience dependence without any influence from the surroundings and that elderly patients who are hospitalized lose their autonomy, follow entirely their doctor's prescriptions, use aid equipment and directions, and depend only on those things. 〈Frustration〉 means that the elderly experience the loss of their roles from the past, there by feeling that there is no work for them to do anymore and therefore feel unable to do anything. 〈Worthlessness〉 means that the elderly experience the feeling of losing their social roles from the past, having no financial ability, thereby being a burden to their children or the people around them, and therefore regarding themselves useless. 〈Giving up〉 means that the elderly experience the feeling of closeness to death in the final stage of their lifetime, lose hope to be healed from their disease, and recognize the incontrollability of their own body. 3. From a general view of the meaning of the theme the powerlessness in the elderly-the most essential meaning of the theme is the 〈sense of loss〉. For the elderly are experiencing a sense of loss in the situation of being elderly and therefore being often hospitalized. Brief definitions of the five phenomena could be 〈weakness〉 meaning the loss of physical strength, 〈dependence〉 the loss of mentality caused by disease and hospitalization, 〈frustration〉 and 〈worthlessness〉 the loss of social performance caused by the loss of social functions from the past, and lastly 〈giving up〉 the loss of the controllability of such situations of aging and suffering disease. In light of the discussion above, it is understandable that the hospitalized elderly experience powerlessness not only as it related to their diseases but also to their normal aging, and this related to other characteristics of being elderly means that the 〈sense of loss〉 is the very essence of their powerlessness. 4. While most cases are of the normal elderly experiencing powerlessness in relation to their social network, cases of elderly who are hospitalized are of those experiencing powerlessness in relation to the loss of their physical desire. 5. The findings discussed above can serve as guidelines for nurses who take care of the ill elderly who are hospitalized and that can provide cues to appropriate nursing service, recognizing that the subjective experience of the objective age of the elderly is so important. Nurses can provide highly qualitative nursing service, based on their deep understanding of the suffering of the elderly due to feelings of powerlessness.

• Journal of the Korean earth science society
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• v.39 no.3
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• pp.241-249
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• 2018

As the international trade increases, vessel traffics around the Korean Peninsula are also increasing. Maritime accidents hence take place more frequently in the southern coast of Korea where many big and small ports are located. Accidents involving ship collision and sinking result in a substantial human and material damage as well as the marine environmental pollution. Therefore, it is necessary to locate the ships quickly when such accidents occur. In this study, we suggest a new ship detection index by comparing and analyzing the reflectivity of each channel of the Korea MultiPurpose SATellite-2 (KOMPSAT-2) images of the area around the Gwangyang Bay. A threshold value of 0.1 is set based on a histogram analysis, and all vessels are detected when compared with RGB composite images. After selecting a relatively large ship as a representative sample, the distribution of spatial reflectivity around the ship is studied. Uniform shadows are detected on the northwest side of the vessel. This indicates that the sun is in the southeast, the azimuth of the actual satellite image is $144.80^{\circ}$, and the azimuth angle of the sun can be estimated using the shadow position. The reflectivity of the shadows is 0.005 lower than the surrounding sea and ship. The shadow height varies with the position of the bow and the stern, perhaps due to the relative heights of the ship deck and the structure. The results of this study can help search technology for missing vessels using optical satellite images in the event of a marine accident around the Korean Peninsula.

• Tuberculosis and Respiratory Diseases
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• v.57 no.2
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• pp.168-179
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• 2004

Background : The statistical analysis is an essential procedure ensuring that the results of researches are based on evidences rather than opinion. The purpose of this study is to evaluate which statistical techniques are used and whether these statistical methods are used appropriately or not in the journal of Tuberculosis and Respiratory Diseases. Materials and Methods : We reviewed 185 articles reported in the journal of Tuberculosis and Respiratory Diseases in 1999. We evaluated the validity of used statistical methods based upon the checklist that was developed on the basis of the guideline for statistical reporting in articles for medical journals by International Committee of Medical Journal Editors. Results : Among 185 articles, original articles and case reports were 110 (59.5%) and 61 (33.0%) respectively. In 112 articles excluding case reports and reviews, statistical techniques were used in 107 articles (95.5%). In 94 articles (83.9%) descriptive and inferential methods were used, while in 13 (11.6%) articles only descriptive methods were used. With the types of inferential statistical techniques, comparison of means was most commonly used (64/94, 68.1%), followed by contingency table (43/94, 45.7%) and correlation or regression (18/94, 19.1%). Among the articles in which descriptive methods were used, 83.2% (89/107) showed inappropriate central tendency and dispersion. In the articles in which inferential methods were used, improper methods were applied in 88.8% (79/89) and the most frequent misuse of statistical methods was inappropriate use of parametric methods (35/89, 39.3%). Only 14 articles (13.1%) were satisfactory in utilization of statistical methodology. Conclusion : Most of the statistical errors found in the journal were misuses of statistical methods related to basic statistics. This study suggests that researchers should be more careful when they describe and apply statistical methods and more extensive statistical refereeing system would be needed.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.1
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• pp.87-102
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• 2015

This study attempts to introduce the methodology for accounting real-time population distribution in the urban areas. For the purpose, we utilize the media user's time-space information from the media users' media diaries in the media panel survey databases. We analyze the space-time population rate for each activity space related with everyday urban lifes. Seoul has been selected as a case study area, since space-time information are relatively rich there, and thus the comparisons are available. The space-time population rates have been verified by the comparative analysis with the T-card results. We propose a real time population measurement method by combination of the space-time population rate with geographical data. The real time population of each activity space at each dong in Seoul has been calculated by multiplying the space-time population rates to the numbers of employer of three categories of activity spaces(residential, working, and commercial). By utilizing GIS, we visualize the results of two time points (3AM and 3PM) and then analyze the spacio-temporal characteristics of real time population distribution in Seoul. The Day time population distribution pattern shows strong relationships with the distribution of business and commercial activities, while the night time population distribution pattern can be explained by resident population distribution almost perfectly.

• Journal of Korean Academy of Nursing
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• v.22 no.4
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• pp.506-525
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• 1992

Older people, because of the psychological and physiological changes related to the aging process are more vulnerable to experiencing powerlessness than any other age group. This self destructive cycle of depression in older people related to the experience of continued and long term powerlessness can lead even to death. The purpose of this study was to measure powerlessness and resources to increase power in older people, and to measure the effectiveness of a psychological rehabilitation program for reducing powerlessness. The research methodology used was a two step process. In the first step, a survey was done of perceived powerlessness and power resources comparing four groups of elderly people ; those living at home, those in hospital, those living in nursing homes and those attending educational programs for the elderly. The total sample size was 236. In the second step, a psychological rehabilitation program was carried out, pre and post measurements were taken related to this program. The sample consisted of 29 residents in a nursing home. The results of the study are as follows : 1. Powerlessness was classified as cognitive, emotional, activity and learning. The lowest score for powerlessness was in the area of activity, that is the people in the sample felt more power concerning their activities. The highest score was in the area of cognition where they felt they had less power. 2. When the different groups of elderly were compared, it was found that the residents of the nursing home had the highest score on perceived powerlessness and the group who were living at home had the lowest score. 3. Among the general characteristics, the factors influencing the powerlessness score were age, sex, level of education, financial resources and health status. In the interaction effects among these factors, it was found that level of education and health status were factors influencing perceived powerlessness. The elderly with lower education and poorer health status had the higher scores for perceived powerlessness. 4. The power resources could be classified into the following areas : physical strength, emotional strength, positive self-image, energy, knowledge, motivation and belief system. Belief system was given the highest score among the power resources and energy, knowledge and motivation were given low scores. 5. The group participating in an educational program for the elderly had the highest score for power resources while the group made up of residents of a nursing home had the lowest score as well as the highest score for perceived powerlessness. 6. The factors influencing the power resource scores were sex, level of education, financial resources and health status. In the analysis of the interaction effect among the factors, it was found that sex, level of education and financial resources were the factors that influenced the power resource score, that is, women, those with a low level of education and those with poor financial resources reported a lower level of power resources. 7. There was a negative correlation between perceived powerlessness and power resources in the elderly in this study. Since power resources explainded 49% of the variance for powerlessness, it can be concluded that the power resources can be used to reduce powerlessness. 8. The psychological rehabilitation program was carried out with the nursing home residents over a period of five weeks. No statistically significant difference was found in the scores on powerlessness between the pre and post tests, but there was a slight decrease in the raw scores on the post test for emotional, activity and learning powerlessness. There was a statistically significant increase in the power resource scores for emotional strength, positive self-image, energy, knowledge and motivation in the post test as compared to the pre test. In conclusion, the study indicates that a psychological rehabilitation program for the elderly could be effective in increasing power resources and this in turn could lead to a decrease in perceived powerlessness.

• Journal of Korean Academy of Nursing
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• v.24 no.4
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• pp.623-634
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• 1994

Although the average menopausal age has not changed, women's life span has increased. Today's women live longer after their menopause than those in the past, and this calls for attention in both nursing and medical fields. Many studies have revealed how women reacted to menopause and suffered from it. But they did not discriminate the menopausal meaning and effects from the climacteric phenomena. So, this author tried to clarify what menopause itself meant to the climacteric women, by means of grounded theory methodology. The interviewees were 21 women, whose ages were between 46 and 60 years. They were selected by theoretical sampling technique, and the author tried to include all levels of important variables such as age, educational background, religion and job. Data were collected by the author through in -depth interviews and observations in July, 1994. The interviews were mostly done in the homes of the subjects, or in some cases at the author's office or in a hospital. Interviews took from 30 minutes to 2 hours. Interviews were tape recorded and transcribed later by a research assistant. Data were analyzed as gathered, by the constant comparative method proposed by Strauss and Corbin. Eleven concepts were discovered from the data, and they were grouped under six higher order categories. These six categories were "to give menopause a meaning", "to experience value change", "to have self-help strategies", "to have no strategies", "to live a life worth living", "to have a sense of powerlessness" Among these "to experionce value change" was . selected as the core category. Five major categories were systematically integrated around the core category. Women's adaptation to menopause was defined as proceeding as follows : Most women felt relief and sorrow at the same time when they faced menopause, and some only sorrow or agony. Then, they consulted with others about menopausal symptoms, or tried to think of them by themselves. Finally, they gave menopause a meaning, which was that menopause and its symptoms were natural phenomena. But menopause made women reflect on them-selves and their past lives. As they reflected on themselves, their value on life began to change. As their value changed, some women seeked self help strategies. Those self help strategies were what they had learned from collegues, professionals or mass media. The quality of their lives depended on whether they practiced self help strategies or not. Three types of lives were found. Twelve women enjoyed a life worth living, and practiced the self help strategies, because they accepted menopause a chance to change. They were characterized by a high educational level, having a professional job and a sincere faith in God. Seven women were living as usual, because they did not have the necessity to change. They were high school graduates and house wives. Two women recognized menopause a chance to change, but they did not try self help strategies. Their characteristic was low educational level. Those who did not try self help strategies complained of powerlessness to varying degrees. The educational background, full-time jobs and faith helped women adapt to menopause positively. But social support was not helpful to women's adaptation to menepause. Three hypotheses were derived from the analysis. (1) The higher the educational level, the more theneed to change. (2) Women with higher educational background will practice self help strategies more than those with lower edcational background. (3) The more women practice self help strategies, the worthier lives they will live. Suggestions for further studies are as follows. (1) Studies to test hypotheses are needed. (2) A study to find the relationship between the degree of practicing self help strategies and locus of control. (3) Spiritual approaches would better be applied to help menopausal women. (4) Education through mass media should be given mere frequently.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.169-179
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• 1999

The present study was undertaken to classify and describe the spring naturalized plant communities in old-Andong city by the methodology of the ZM school of phytosociology. As a result, the vegetation was classified into the six communities and two subcommunities: A. Bromus tectorum community A-a. Bromus japonicus subcommunity, A-b. Melica onoei subcommunity; B. Poa pratensis community; C. Rumex crispus community; D. Oenothera lamarckiana community; E. Ambrosia artemisiifolia var. eiatior community; F. Rumex conglomeratus community. The total taxa of the naturalized plant communities consisted of 31 families, 86 genera, 114 species and 13 varieties. Of which the taxa of the naturalized plant species consisted of 8 families, 21 genera, 25 species and 1 variety. The result of Bray-Curtis ordination revealed that the plots suveyed were arranged according largely to the vegetation units of' the communities. Also the interspecific affinity was examined by an analysis of interspecific association and the main component species in the communities were divided into two groups. The naturalized rate was higher in the communitise affected by strong human impacts, while was lower in the communities affected relatively less by human impacts. On the other hand the seasonal changes of the communities and the naturalized rate between the spring and the autumn were investigated. Many naturalized communities present in Spring were replaced by the other native ruderal communitues in the Autumn. The naturalized rate based on the dominance was largely decreased over from the spring to the Autumn.

• The Korean Journal of Financial Management
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• v.24 no.2
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• pp.41-79
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• 2007

This study examines the expiration-day effects of stock index futures and options in the Korean stock market. The so-called 'expiration-day effects', which are the abnormal stock price movements on derivatives expiration days, arise mainly from cash settlement. Index arbitragers have to bear the risk of their positions unless they liquidate their index stocks on the expiration day. If many arbitragers execute large buy or sell orders on the expiration day, abnormal trading volumes are likely to be observed. If a lot of arbitragers unwind positions in the same direction, temporary trading imbalances induce abnormal stock market volatility. By contrast, if some information arrives at market, the abnormal trading activity must be considered a normal process of price discovery. Stoll and Whaley(1987) investigated the aggregate price and volume effects of the S&P 500 index on the expiration day. In a related study, Stoll and Whaley(1990) found a similarity between the price behavior of stocks that are subject to program trading and of the stocks that are not. Thus far, there have been few studies about the expiration-day effects in the Korean stock market. While previous Korean studies use the KOSPI 200 index data, we analyze the price and trading volume behavior of individual stocks as well as the index. Analyzing individual stocks is important for two reasons. First, stock index is a market average. Consequently, it cannot reflect the behavior of many individual stocks. For example, if the expiration-day effects are mainly related to a specific group, it cannot be said that the expiration of derivatives itself destabilizes the stock market. Analyzing individual stocks enables us to investigate the scope of the expiration-day effects. Second, we can find the relationship between the firm characteristics and the expiration-day effects. For example, if the expiration-day effects exist in large stocks not belonging to the KOSPI 200 index, program trading may not be related to the expiration-day effects. The examination of individual stocks has led us to the cause of the expiration-day effects. Using the intraday data during the period May 3, 1996 through December 30, 2003, we first examine the price and volume effects of the KOSPI 200 and NON-KOSPI 200 index following the Stoll and Whaley(1987) methodology. We calculate the NON-KOSPI 200 index by using the returns and market capitalization of the KOSPI and KOSPI 200 index. In individual stocks, we divide KOSPI 200 stocks by size into three groups and match NON-KOSPI 200 stocks with KOSPI 200 stocks having the closest firm characteristics. We compare KOSPI 200 stocks with NON-KOSPI 200 stocks. To test whether the expiration-day effects are related to order imbalances or new information, we check price reversals on the next day. Finally, we perform a cross-sectional regression analysis to elaborate on the impact of the firm characteristics on price reversals. The main results seem to support the expiration-day effects, especially on stock index futures expiration days. The price behavior of stocks that are subject to program trading is shown to have price effects, abnormal return volatility, and large volumes during the last half hour of trading on the expiration day. Return reversals are also found in the KOSPI 200 index and stocks. However, there is no evidence of abnormal trading volume, or price reversals in the NON-KOSPI 200 index and stocks. The expiration-day effects are proportional to the size of stocks and the nearness to the settlement time. Since program trading is often said to be concentrated in high capitalization stocks, these results imply that the expiration-day effects seem to be associated with program trading and the settlement price determination procedure. In summary, the expiration-day effects in the Korean stock market do not exist in all stocks, but in large capitalization stocks belonging to the KOSPI 200 index. Additionally, the expiration-day effects in the Korean stock market are generally due, not to information, but to trading imbalances.