• Restorative Dentistry and Endodontics
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• 제18권1호
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• pp.84-94
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• 1993

The purpose of this study was to evaluate flexure strength of composite resin inlay according to heat treatment and duration in comparasion with visible light-cured resin. In this study, materials were used 1 visible light-cured resin and 3 kinds of composite resin inlays. Control group was visible light cured resin (Photo Clearfil Posterior) and experimental groups were composite resin inlays (Brilliant Dentin, Brilliant Enamel and Clearfil CR Inlay). Experimental groups were divided 3 groups: First group was Brilliant Dentin and second group was Brilliant Enamel and -third group was Clearfil CR Inlay. Used experimental groups were calculated flexural strength according to heat treatment and duration. The following results were obtained: 1. Experimental groups were higher flexural strength than control group. 2. At $100^{\circ}C$ when heat treatment carried out 7 minutes flexural strength elevated third group, second group, first group in turn and when heat treatment carried out 15 minutes flexural strength elevated third group, second group, first group in turn but no difference was showed between first and second group. 3. At $125^{\circ}C$ when heat treatment was carried out 7 minutes flexural strength elevated third group, second group, first group in turn and when heat treatment was carried out 15 minutes flexural strength elevated third group, first group, second group in turn but no difference was showed between first and second group. 4. In spite of heat treatment and duration the third group was highest flexural strength in the others groups.

• 한국가정과교육학회지
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• 제13권3호
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• pp.69-84
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• 2001

The purpose of the present study is to investigate the relationship between self-concept and clothing behavior of elementary school children. For this purpose. 301 third and sixth graders two schools in Daegu-city were sampled. The \`Test of Self-Concept\` and \`Questionnaire on the Clothing Behavior\` were administered purpose of this study. The collected data were analyzed by the SPSS/PC Windows programs according to the research issues. Means and standard deviations were calculated and a three-way analysis of variance was applied to analyze the effects of grades, sex(gender) and self-concept on the clothing behavior. The major results of this study were as follows: 1. It was found that the mean score of the clothing behavior was significantly different depending the level of self-concept (group). The mean scores of manageability. psychological dependency interest and conformity of the high self-concept. group were significantly higher than those of the low self-concept group. But. there was no significant difference between the high and low self-concept groups in the mean score of comformity. 2. There were statistically significant differences between the sex of children in the mean score of the clothing behavior. It was found that the mean score of manageability, psychological dependency and interest of the female students were significantly higher than those of the male students. However the mean score of the comfortability of male students was significantly higher than that of the female students. In the meantime there was no significant difference between the sex of students in the mean score of comformity. 3. There were statistically significant differences in the mean score of the clothing behavior according to the graders of children . It was found that the mean scores of manageability, psychological dependency, interest and comfortability of the third graders were significantly higher those that of the sixth graders. But, there was no significant difference depending the grades of students in the mean score of conformity. 4. There were statistically significant interaction effects between the sex and the grade of children on the mean score of interest and comfortability. It was found that the mean score of interest of male third graders was higher than that of male sixth graders. The mean score of comfortability of the female third graders higher than that of sixth graders.

• 대한예방한의학회지
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• 제5권1호
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• pp.10-30
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• 2001

Oriental medicine needs to be armed with theories on health-improvement concept under it and basic data matching its views, in order to participate in the health-improvement service in industrial work places. The Orient medicine health-improvement program defines factors that determine individuals' lifestyle, and provides information and technologies for workers to practice in life. To that end, this research compares and analyzes health-improvement concept and health care, defines relations between individuals' health state and their lifestyle as the basic data needed to perform health-improvement business for workers. 1. The subjects employed for this research is categorized into; by gender, males 52.1% and females 47.9% with no big difference between them; and by age, 20s, 6.1%, 30s. 33.9%, 40s, 34.1%, and 50s, 24.8% with 30-50 accounting for most of it. By marriage status, unmarried represents 7.1%, and married 79.1% with most of them married; by revenue, under one million won represents 3.0%, 1-2 million won 26.4%, 2-2.49 million won 11.2%, above 2.5 million won 11.2%, and 1-2.5 million won a majority. By living location, owned houses represents 65.4%, rented houses 14.7%, monthly-rented 9.5%; and by education, elementary and middle school represent 16.9%, high school and its dropouts 22.6%, and junior college and higher 51.6%, with high school and higher occupying most of the group. 2. By job, office workers and managerial workers represent 12.3%, part-timers 21.0%, manual workers 11.4%, jobless 0.6%, professionals 35.6%, service 0.6%, housewives 8.4%, and equipment/machinery operation/assemblers 10.1%. Of this, jobless and part-timers, totaling three, are dropped from this research. By years worked, 0-3.9 years represents 9.7%, 4-7.9 years 6.7%, 8-14.9 years 18.4%, above 15 years 28.7%, and no respondents 36.5%. 3. The degree of the subjects practicing life-improvement lifestyle, on a scale of 1 to 4, is an average of 2.69, personal relations 3.04, self-realization 2.92, stress management 2.76, nutritional state 2.73, responsibility for health 2.47, and athletic activities 2.18, with personal relations earning the highest points and athletic activities the lowest. As for factors influencing health-improvement lifestyle, there is no significant difference between gender, age, and marriage status. Meanwhile, there is significant difference between revenue, dwelling pattern, education level, etc. That is, higher income-bracket, owned houses, rented houses, monthly-rented houses, and higher-educated, in this order, show higher average in health-enhancement lifestyle. By job, housewives, manual workers, office workers, professionals, equipment/ machinery operation/ assemblers, and part-timers, in this order show higher points, while there is no difference with significance by years worked. 4. Factors that affect health-improvement lifestyle are shown below. Self-realization is influenced by age, marriage status, type of dwellings, and level of education; responsibility for health by type of dwellings; athletic activities by gender and age; nutrition by age, marriage status and type of dwellings; personal relations by marriage status; and stress management by type of dwellings. 5. Areas with high points by job show this: in self-realization, office workers, manual workers, housewives, professionals, equipment/ machinery operation/ assemblers, in this order, show difference with significance; in the area of responsibility for health, manual workers, housewives, equipment/ machinery operation/ assemblers, professionals, office workers and part-timers, in this order, do. In athletic activities, manual workers, housewives, office workers, professionals, equipment/ machinery operation/ assemblers, and part-timers, in this order, show difference with significance; in nutrition, housewives, office workers, manual workers, professionals, equipment/ machinery operation/ assemblers, and part-timers, in this order do; and in stress, housewives, office workers, manual workers, professionals, equipment/ machinery operation/ assemblers, part-timers, in this order do. By years worked, more years showed higher points in the area of responsibility for health and nutrition; in the area of athletic activities, above 15 years, 4-8 years, below 4 years and 8-14 years, in this order, show higher points; and no difference shows in realization, personal relation, and stress area. 6. To look at correlation between overall and divisional health-improvement practice degree, this researcher has analyzed it using Person's correlation coefficient. Self-realization, responsibility for health, athletic activities, nutrition, support for personal relations, and stress management show significant correlation with the sub-divisions, while all health-improvement lifestyle shows significant correlation with the six sub-divisions.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권3호
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• pp.163-171
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• 2023

Background: Surgical extraction of impacted mandibular third molars is the most common procedure performed by oral surgeons. The procedure cannot be performed effectively without achieving profound anesthesia. During this procedure, patients may feel pain during surgical bone removal (at the cancellous level) or during splitting and luxation of the tooth, despite administration of routine nerve blocks. Administration of intraosseous (IO) lignocaine injections during third molar surgeries to provide effective anesthesia for pain alleviation has been documented. However, whether the anesthetic effect of lignocaine is the only reason for pain alleviation when administered intraosseously remains unclear. This conundrum motivated us to assess the efficacy of IO normal saline versus lignocaine injections during surgical removal of impacted mandibular third molars. The aim of this study was to assess the efficacy of IO normal saline as a viable alternative or adjunct to lignocaine for alleviation of intraoperative pain during surgical removal of impacted mandibular third molars. Methods: This randomized, double-blind, interventional study included 160 patients who underwent surgical extraction of impacted mandibular third molars and experienced pain during surgical removal of the buccal bone or sectioning and luxation of the tooth. The participants were divided into two groups: the study group, which included patients who would receive IO saline injections, and the control group, which included patients who would receive IO lignocaine injections. Patients were asked to complete a visual analog pain scale (VAPS) at baseline and after receiving the IO injections. Results: Of the 160 patients included in this study, 80 received IO lignocaine (control group), whereas 80 received IO saline (study group) following randomization. The baseline VAPS score of the patients and controls was 5.71 ± 1.33 and 5.68 ± 1.21, respectively. The difference between the baseline VAPS scores of the two groups was not statistically significant (P > 0.05). The difference between the numbers of patients who experienced pain relief following administration of IO lignocaine (n=74) versus saline (n=69) was not statistically significant (P > 0.05). The difference between VAPS scores measured after IO injection in both groups was not statistically significant (P >0.05) (1.05 ± 1.20 for the control group vs. 1.72 ± 1.56 for the study group) Conclusion: The study demonstrates that IO injection of normal saline is as effective as lignocaine in alleviating pain during surgical removal of impacted mandibular third molars and can be used as an effective adjunct to conventional lignocaine injection.

• 대한전기학회논문지:전력기술부문A
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• 제51권10호
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• pp.495-501
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• 2002

A difference based current transformer (CT) saturation detection algorithm uses the third difference of a secondary current to detect the instants of the beginning/end of saturation. The third difference of a secondary current contains high frequency components when a CT is saturated. Thus, an effect of an anti-aliasing lowpass filter implemented in digital protection relays on the detection algorithm should be studied. This paper describes performance analysis of a lowpass filter on the CT saturation detection algorithm. The cutoff frequency of the lowpass filter is normally set to be half of a sampling frequency. In this Paper, two sampling frequencies of 3,840 (Hz) corresponding to 64 sample/cycle (s/c) and 1,920 (Hz) corresponding to 32 (s/c) are studied; the cutoff frequencies of the lowpass filters are set to be 1,920 (Hz), 960 (Hz) and 960(Hz), 480(Hz), respectively. And the proposed algorithm is verified by experiment. A 2nd order Butterworth filter is designed as a lowpass filter. The test results and experiment results clearly indicate that the saturation detection algorithm successfully detects the instants of the beginning/end of saturation even though a secondary current is filtered by the designed lowpass filters.

• 한국환경과학회지
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• 제22권11호
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• pp.1443-1449
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• 2013

This was an experimental study to evaluate temperature reduction and evapotranspiration of extensive green roof. Three test cells with a dimension of $1.2(W){\times}1.2(D){\times}1.0(H)$ meters were built using 4-inch concrete blocks. Ten-centimeter concrete slab was installed on top of each cell. The first cell was control cell with no green roof installed. The second and third cells were covered with medium-leaf type Zoysiagrass (Zoysia japonica) above a layer of soil. Soil thickness on the second cell was 10cm and that on the third cell was 20cm. Air temperature, relative humidity and solar irradiance were measured using AWS (automatic weather system). Temperature on top surface and ceiling of the control cell and temperature on top surface, below soil and ceiling of green roof cells was measured. Evapotranspiration of the green roof cells were measured using weight changes. Compared with temperature difference on the control cell, temperature difference was greater on green roof cells. Between two green roof cells, the temperature difference was greater on the third cell with a thicker soil layer. Temperature differences below soil and on ceilings of green roof cells were found greater than those of the control cell. Between the green roof cells, there was no difference in the temperature reduction effects below soil and on ceilings based on substrate depth. In summary, green roof was found effective in temperature reduction due to evapotranspiration and shading effect.

• Journal of Dental Anesthesia and Pain Medicine
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• 제19권6호
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• pp.379-388
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• 2019

Background: In dentistry, pain is a factor that negatively affects treatments and drug use. The aim of this study was to evaluate the correlations of the postoperative analgesic use with pain catastrophizing and anxiety in patients who underwent removal of an impacted mandibular third molar. Methods: We recruited 92 patients who underwent the extraction of impacted mandibular third molar. In this study, the Pederson index was used to preoperatively determine the difficulty of surgical extraction. Patients were asked to note the number of analgesics used for 7 postoperative days. Patients were divided into two groups based on the Pain Catastrophizing Scale: low and high score groups. State-Trait Anxiety Inventory-trait and State-Trait Anxiety Inventory-state questionnaires were used to determine the anxiety levels of the patients. The obtained data were examined to evaluate the correlations of pain catastrophizing and anxiety with the postoperative analgesic use. Results: In this study, 92 patients, including 60 women and 32 men, were recruited. The analgesic use was higher in women than in men but with no significant difference (P > 0.05). Pain Catastrophizing Scale scores were higher in women than in men but with no significant difference (P > 0.05). The analgesic use was higher in patients with high pain catastrophizing than in those with low pain catastrophizing but with no significant difference (P > 0.05). State-Trait Anxiety Inventory-trait scores were higher in women than in men but with no significant difference. However, state-Trait Anxiety Inventory-state scores were significantly higher in women than in men (P < 0.05). Conclusion: The postoperative analgesic use may be higher in patients who catastrophize pain than in others. Knowing the patient's catastrophic characteristics preoperatively would contribute to successful pain management and appropriate drug selection.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.30.1-30.7
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• 2015

Background: The inferior alveolar nerve (IAN) may be injured during extraction of the mandibular third molar, causing severe postoperative complications. Many methods have been described for evaluating the relative position between the mandibular third molar and the inferior alveolar canal (IAC) on panoramic radiography and computed tomography, but conventional radiography provides limited information on the proximity of these two structures. The present study assessed the benefits of three-dimensional computed tomography (3D-CT) prior to surgical extraction of the mandibular third molar, to prevent IAN damage. Methods: This retrospective study included 4917 extractions in 3555 patients who presented for extraction of the mandibular third molars. The cases were classified into three groups, according to anatomical relationship between the mandibular third molars and the IAC on panoramic radiography and whether 3D-CT was performed. Symptoms of IAN damage were assessed using the touch-recognition test. Data were compared using the chi-square test and Fisher's exact test. Results: Among the 32 cases of IAN damage, 6 cases were included in group I (0.35 %, n = 1735 cases), 23 cases in group II (1.1 %, n = 2063 cases), and 3 cases in group III (0.27 %, n = 1119 cases). The chi-square test showed a significant difference in the incidence of IAN damage between groups I and II. No significant difference was observed between groups I and III using Fisher's exact test. In the 6 cases of IAN damage in group I, the mandibular third molar roots were located lingual relative to the IAC in 3 cases and middle relative to the IAC in 3 cases. The overlap was ${\geq}2mm$ in 3 of 6 cases and 0-2 mm in the remaining 3 cases. The mean distance between the mandibular third molar and IAC was 2.2 mm, the maximum distance 12 mm, and the minimum distance 0.5 mm. Greater than 80 % recovery was observed in 15 of 32 (46.8 %) cases of IAN damage. Conclusions: 3D-CT may be a useful tool for assessing the three-dimensional anatomical relationship and proximity between the mandibular third molar and IAC in order to prevent IAN damage during extraction of mandibular third molars.

• Journal of applied mathematics & informatics
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• 제38권1_2호
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• pp.1-12
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• 2020

In this paper, we solve the difference equation $x_{n+1}={\frac{x_nx_{n-2}}{ax_n-bx_{n-2}}}$, n = 0, 1, …, where a and b are positive real numbers and the initial values x_-2, x_-1 and x₀ are real numbers. We also find invariant sets and discuss the global behavior of the solutions of aforementioned equation.

• 한국공작기계학회논문집
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• 제14권4호
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• pp.1-6
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• 2005

In this study, on automatic ultrasonic testing system is used to detect defects of flawtest specimen. We study the effects of the difference of ultrasonic damped rate of the different materials on the judgment of defects. The results indicate that the difference of sensitivity compensating quantity is 2dB, and the judgment is correct over $90\%$ when a specimen is judged as a defect when it exceeds third grade.