• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.67-74
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• 2008

This paper proposes two peak-windowing algorithms for peak-to-average power reduction(PAPR) of orthogonal frequency division multiple access(OFDMA) downlink systems. The Proposed algorithms mitigate the effect of excessive suppression due to successive peaks or relatively high peaks of the signal. First, multi-stage peak windowing algorithm is proposed, which exploits multiple threshold of target PAPR in order to step down the peaks gradually. Secondary, variable-length peak windowing algorithm is proposed, which adapts the window length with respect to the existence of successive peaks within a half of window length. Therefore, the proposed method reduces the distortion of signal amplitude caused by window overlapping. The proposed algorithms outperform the conventional peak windowing with the aid of window-length adaptation or sequential peak power reduction. Simulation results show the efficiency of the proposed algorithms over OFDMA downlink systems, especially WiBro systems.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1025-1032
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• 2005

This paper presents experimental and analytical studies on long-term behavior of square CFT columns with diaphragm. In order to investigate the effect of the diaphragm on the long~term behavior, experiments for six specimens with two diaphragms and three different column length, and three-dimensional finite element analysis for each specimen have been performed. The finite element models considering the interface behavior between the steel tube and the inner concrete were verified from comparison of the test results with the analysis results. From the test and the analysis results, the following conclusions were obtained. The confinement effect created by the diaphragm does not depends on column length and influences only a part of the whole column that is from the end to the depth which is the same to the width of the column. The shortening of the column with diaphragm which covers more than a half of the cross sectional area of the inner concrete is the same as that of the column under a load applied on the steel tube and the entire section of the inner concrete.

• Journal of Korean Academy of Nursing
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• v.46 no.6
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• pp.804-812
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• 2016

Purpose: This research was done to identify the hospital arrival rate and factors related to prehospital delay in arriving at an emergency medical center within the golden time after symptom onset in patients with acute myocardial infarction (AMI). Methods: Data used in the research was from the National Emergency Department Information System of the National Emergency Medical Center which reported that in 2014, 9,611 patients went to emergency medical centers for acute myocardial infarction. Prehospital time is the time from onset to arrival at an emergency medical center and is analyzed by subdividing arrival and delay based on golden time of 2 hour. Results: After onset of acute myocardial infarction, arrival rate to emergency medical centers within the golden time was 44.0%(4,233), and factors related to prehospital delay were gender, age, region of residence, symptoms, path to hospital visit, and method of transportation. Conclusion: Results of this study show that in 2014 more than half of AMI patients arrive at emergency medical centers after the golden time for proper treatment of AMI. In order to reduce prehospital delay, new policy that reflects factors influencing prehospital delay should be developed. Especially, public campaigns and education to provide information on AMI initial symptoms and to enhance utilizing EMS to get to the emergency medical center directly should be implemented for patients and/or caregivers.

• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.531-541
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• 1996

Periodontal disease is characterized by destruction of supporting tissues caused by invasion of plaque bacteria and defense mechanism of host. Many dentists are very interested in laser therapy on various intraoral soft tissue lesions including inflammatory periodontal pocket. In order to determine the therapeutic effect of intrapocket irradiation of a pulsed- Nd : YAG laser on the inflammatory periodontal pockets, bilateral 60 teeth with 4-6mm in probing pocket depth and gingival inflammation were selected and evaluated by sulcus bleeding index(SBI), and plaque index(pI) for baseline record. Intrapocket irradiation($300{\mu}m$ fiber optic, I.5W power, for 2 min.) of a pulsed-Nd : YAG laser(EL.EN.EN060, Italy) was applied on half of them. As the control group, the same procedure except power-off was repeated on the contralateral 30 teeth. At 1-, 2-, 3-, and 4-week after intrapocket manipulation, every tooth was reevaluated by the same clinical indices. And the difference between the lased group and control group was statistically analyzed by paired t-test and Chi-square test in Microstat program. Following results were obtained: 1. Until I-week and 2-week after intrapocket manipulation, SBI was lowered in both lased group and control group, compared to baseline SBI, but from 3-week after, the recovering tendency toward baseline was noted, and at only 2-week after, the number of teeth showing lowered SBI was significantly more in lased group than in control group(p<0.05). 2. PI of both lased group and control group was lowered through whole experimental period from I-week to 4-week after, compared to baseline PI(p<0.05), but there was no significant difference between lased group and control group(p>0.1). The results suggest that intrapocket irradiation of a pulsed-Nd:YAG laser may lead somewhat remission of gingival inflammation, but for more favorable therapeutic result the thorough root planing should be necessarily accompanied with gingival curettage.

• Particle and aerosol research
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• v.13 no.4
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• pp.151-158
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• 2017

Electrostatic precipitator is widely used to remove particulate matters in indoor air and industrial flue gas due to low pressure drop and high collection efficiency. However, it has a low collection efficiency for the submicrometer sized particles. Electrospraying is a potential method to increase the particle charging efficiency, which results in increased collection efficiency. Although particle charging efficiency is highly dependent upon droplet size, the effective measuring method of the droplets is still uncertain. Tap water was electrosprayed in this study, and the images of electrosprayed droplets were taken with a high speed camera coupled with several visualization methods in order to measure the droplets size. The droplet size distribution was determined by an image processing with an image-J program. As a result, a droplet measured by a laser visualization, had a half size of that by a Xenon light visualization. In addition, the experimentally measured droplet sizes were a good agreement with the predicted values suggested by $Fern{\acute{a}}ndez$ de la Mora and Loscertales(1994).

• Journal of the Korean Home Economics Association
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• v.24 no.4
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• pp.57-68
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• 1986

The present survey was designed to investigate correlations among blood pressure, nutritional intakes, and various environmental factors in Korean adult males, and to observe the difference in dietary intakes between hypertensive patients and normotensive subjects. Two hundred forty-three adult men from Seoul and rural areas were interviewed about their food intakes, dietary patterns, food habits, and general environmental factors from December 20, 1982 to February 15, 1983. Their dietary intakes were surveyed by means of 24-hour recall diet method. Dietary score card was used in order to evaluate the quality of routine diet of the subject. Variables of environmental factors and factors related to hypertension were expressed as percentage, and the differences in nutrient intake and food score of each sub-group were examined by means of t-test. Correlation of all the variables were analyzed by Pearsons Correlation Coefficient. The results obtained are summarized as follows: 1. 38% of the subjects were between the ages of 40~49, and about one-half of the subjects were middle or high school graduates. 28% of the subjects earned 210, 000~350, 000 Won per month, and income distribution was almost identical to that of the urban population of Korea. 2. There was more overweight or obese found in the hypertensive patients than in the normotensive subjects. About 40% of the hypertensive patients reported a family history of hypertension, and their knowledge about hypertension was rather poor, but slightly better than the normotensive subjects. The patient group had less adherence to smoking and alcohol compared with the normotensive subjects, but no difference was observed in coffee drinking. The mean value of the blood pressure for the normotensive subjects was 127/86mmHg and 175/109mmHg for the hypertensive group. 3. Nutrient intake for the hypertensive group was lower for most of nutrients than in the healthy group. Hypertensive patients on diet therapy consumed less calories and carbohydrates compared with those who do not follow diet therapy. 4. There was no difference intake of these food groups between patients and the healthy group. Food score was strongly related to consumption of animal protein, saturated fats, Calcium, Iron, Vitamin A, Riboflavin, and Vitamin C, which are prone to be deficient in the typical Korean diet. 5. Blood pressure had a strong positive correlation with age, body weight, and socioeconomic level. In addition, monthly income was positively related with age and education level. 6. Three was a positive relationship between blood pressure and consumption of vegetable protein, and a negative relationship with consumption of Calories, Carbohydrates, Calcium, Iron, Vitamin A, Vitamin B1, Niacin, and Vitamin C. Animal protein intake increased as income and education levels increased, but this tendency was opposite for carbohydrates. In summary, nutritional intakes are strongly correlated with various environmental factors and the level of blood pressure. There was no difference between normotensive and hypertensive subjects with respect to the quality of food consumed except restricting energy and carbohydrate in the patient group.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.92-100
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• 2015

For the purpose of improving the efficiency of the radiation impact assessment of dry interim storage facilities for the spent nuclear fuel of pressurized water reactors (PWRs), radiation impact assessment was performed after the application of sensitivity assessment according to the radiation source term designation method, development of a 2-step calculation technique, and cooling time credit. The present study successively designated radiation source terms in accordance with the cask arrangement order in the shielding building, assessed sensitivity, which affects direct dose, and confirmed that the radiation dosage of the external walls of the shielding building was dominantly affected by the two columns closest to the internal walls. In addition, in the case in which shielding buildings were introduced into storage facilities, the present study established and assessed the 2-step calculation technique, which can reduce the immense computational analysis time. Consequently, results similar to those from existing calculations were derived in approximately half the analysis time. Finally, when radiation source terms were established by adding the storage period of the storage casks successively stored in the storage facilities and the cooling period of the spent nuclear fuel, the radiation dose of the external walls of the buildings was confirmed to be approximately 40% lower than the calculated values; the cooling period was established as being identical. The present study was conducted to improve the efficiency of the Monte Carlo shielding analysis method for radiation impact assessment of interim storage facilities. If reliability is improved through the assessment of more diverse cases, the results of the present study can be used for the design of storage facilities and the establishment of site boundary standards.

• Korean Journal of Social Welfare
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• v.56 no.2
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• pp.195-213
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• 2004

The purpose of this study is to explore and understand the meaning of 'Good Death' that the Korean aged people are generally thinking based on their values and the sentiments. For this purpose, we carried out individual and in-depth interviews with 40 aged persons living in Seoul taking their genders and social-economic status into consideration from March to May 2003. We applied qualitative research method to this study. Eight graduate students were responsible for the interviews. They majored in gerontology or had experiences of field work with old persons. It took an average of one and a half hour and maximum of two hours for each of the interviews. All of the processes of each interview were tape-recorded under the agreement with each interviewee. The main and sub themes from the data can be classified to seven categories according to the Phenomenological Approach designed by Colaizzi(1978). The main theme of good death that most of the interviewees considered was 'Blessed Death', very similar to 'Death Fortune' in the five good fortunes found in Korean tradition and the Confucianism. Also, the main concept is classified to seven sub-themes: (1) Not seeing their children's death; (2) Dying in front of their children; (3) Not to be a burden of their children during their lives; (4) Dying after doing all of their duties as parents; (5) Dying with no pain; (6) Completing the natural span of their lives; and (7) Prepared death. Thus, 'Blessed Death' that Korean aged people consider seems to be very closely related with the lives, health, happiness and success of their children. Based on the findings, we concluded that both social policy makers and social service providers are required to keep in mind the meanings of 'Good death' that most of the Korean aged people consider in order to help them enjoy successful aging during their remaining lives.

• Journal of Home Health Care Nursing
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• v.13 no.1
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• pp.24-32
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• 2006

The purpose of this study is to predict the degree of taking the complementary & alternative therapy in the home care nursing service and provide basic data for the application of it. To accomplish this, degree of general recognition of the complementary & alternative therapy, experiences, degree of concern, applicability of the therapy, and educational need should be studied. This study is a descriptive research survey on the home care nurses working at 73 medical centers out of 125 nationwide who provide hospital based home nursing care. The data was collected from Sep. 20, to Oct. 20, 2004 by ChoiHeyran's questionaries (2002). The data was analyzed by the frequency and the percentage. The results of this study are as follows ; 1. The degree of pre-cognition on the complementary & alternative therapy is very high. Information about the therapy was mostly obtained through medias. Home care nurses understand that he desirable treatment is to practice medical treatment and complementary & alternative therapy simultaneously. While 50% of them have already practiced complementary & alternative therapy among their patients. The most commonly used therapy is Acupressure. And Home care nurses have open and positive attitudes about the complementary & alternative therapy as to answer they aye ready to recommend it to their patients. 2. Over half of the Home care nurses met patients taking complementary & alternative therapy. 94.5% of them think scientific diagnosis on the effect of the therapy. advice from the doctor. and the special working staff is required to apply it on to the home care nursing. 3. 68.5% of the Home care nurses have taken education on the therapy through general comprehensive instructions and supplementary. Most of them want to have a opportunity education on the therapy because they want to provide comprehensive nursing and diversified nursing service. The preferred educations are Hand acupuncture, Acupressure & Massage and Aromatherapy, in that order. Based on the above results, the followings are recommended. 1. A study that stipulates the types, applications, and efficiency assessment of the complementary & alternative therapy practiced by Home care nurses in the home care nursing care procedure. And systematic and scientific nursing intervention be developed.

• KDI Journal of Economic Policy
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• v.14 no.2
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• pp.155-187
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• 1992

The Korean economy has sustained high growth rate for almost three decades, that have been associated with the rapid expansion of manufacturing industries. In the beginning stage of development, the high growth of the Korean economy has been based on improvements in productivity obtained by the economies of scale. In that period, the improvements in productivity could be secured by the economies of scale in the export-oriented industries which are the labor- and material-intensive industries. In the latter half of the 1980s, the Korean economy went through rapid transition. Now Korea is at another juncture in its development process, where economic restructuring is critical to sustain high growth. However, economic restructuring in the 1990s call for much more concerted effort than before, since changes in internal and external conditions have profoundly altered the environment for economic development. If Korea is to sustain high growth in the 1990s, it has to promote balanced economic and social development in coordination with the smooth facilitation of industrial restructuring. There are no inherent conflicts among the issues involved, so they can be resolved by restructuring the economy to facilitate, in a global context, the development of knowledge- and technology-intensive activities and to ensure that the benefts of growth are reflected of qualitative improvements in national living standards. In this paper, we examined a scenario of structural changes using a mid- and long-term multisector model, in order to understand the conditions needed for realizing the growth potential. This examination explains the important features of the development course and policy directions that will help sustain high growth in the 1990s.