• Sleep Medicine and Psychophysiology
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• v.29 no.1
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• pp.15-20
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• 2022

Objectives: Suicide is the major public mental health concerns all over the world. The comparison of suicide attempters and suicide completers could be the fundamental evidence for the suicide prevention. The aim of this study is to explore the differences between suicide attempters and suicide completers in terms of the stressors, suicide methods, and psychiatric diagnosis. Methods: Two types of secondary data were collected for the analyses. Data of the suicide attempters (n = 680) were gathered by intensive reviewing the medical records of Samsung Medical Center, Seoul, Republic of Korea. Data of suicide completers (n = 11,722) were collected by the psychological autopsy data which were gathered by Korean Foundation for Suicide Prevention. Suicidal methods, psychiatric disorders and stressors before suicidal attempt were compared between suicide attempter and completers. Results: Suicide completers were older and male predominant compared to suicidal attempt. Hanging or gas intoxication were more commonly used in the suicide completion, while wrist cutting or drug intoxication were more common in suicide attempters. All types of stressors were found to be high in suicide completers than suicide attempters. However, the proportion of economic and physical stress were greater in suicide completers, while the proportion of family stress were greater in suicide attempters. According to the recorded diagnoses, the rates of depressive disorders, sleep-wake disorders, substance-related disorders were higher in suicide completers, while the rates of anxiety disorders and trauma- and stressor-related disorders, bipolar and related disorders and somatic symptom disorders were higher in suicide attempters. However, after controlling the gender and age, there were no significant differences in diagnosis between suicide attempters and suicide completers. Conclusion: These findings implicate that suicide attempters and completers differed in suicide methods and type of stress. The results suggests that economic stressors, physical illness might raise the risk of suicide completion.

• Analytical Science and Technology
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• v.20 no.4
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• pp.261-267
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• 2007

The 20 L small chamber test method is to evaluate pollutants such as TVOC, formaldehyde emitted from building materials. This method was only designed to evaluate the surface emission of sample exposed in the chamber. In this method, building materials cut with a fixed standard size are fixed in a sample sealing box. The sample sealing box is put into the 20 L test chamber. This chamber is ventilated at a standard air change rate with purified air for 7 days then the sample from the chamber is collected and analyzed to measure the emission rate of TVOC and formaldehyde. In this method, however, if the sealing box does not guarantee airtightness, accurate evaluation for the building materials can not be achieved due to the pollutants emitted from edge of the sample so called, edge effect. This edge effect can be much greater when evaluating panels such as plywood, flooring due to their surface treatment. In this study, flooring was tested to check airtightness of the sample sealing box with analytic results between 1L and 20 L test chamber. Furniture materials like LPM coated one side surface treatment and MDF coated both sides surface treatment with LPM were tested to identify whether the improvement of the sample sealing box airtightness is possible with the comparison between existing and improved test method that low VOC emission tape was used to seal the sample edge. After 7 days, MDF TVOC emission rate was different according to the existence and nonexistence of tape. The emission rate of the existing test method was $0.009mg/m^2h$ and that of improved test method was $0.003mg/m^2h$. Relative standard deviation for the existing test method was $0.004mg/m^2h$ and relative standard deviation for the improved test method was $0.002mg/m^2h$ when the same sample was analyzed three times. The improved test method in this study using low VOC emission tape was effective and able to reduce the heterogeneous effect of the edge from the sample sealing box.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.17-24
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• 2023

A post-processing technique for the measurement signal of a solenoid-type sensor is introduced. The solenoid-type sensor nondestructively evaluates an external tendon of prestressed concrete using the total flux leakage (TFL) method. The TFL solenoid sensor consists of primary and secondary coils. AC electricity, with the shape of a sinusoidal function, is input in the primary coil. The signal proportional to the differential of the input is induced in the secondary coil. Because the amplitude of the induced signal is proportional to the cross-sectional area of the tendon, sectional loss of the tendon caused by ruptures or corrosion can be identified by the induced signal. Therefore, it is important to extract amplitude information from the measurement signal of the TFL sensor. Previously, the amplitude was extracted using local maxima, which is the simplest way to obtain amplitude information. However, because the sampling rate is dramatically decreased by amplitude extraction using the local maxima, the previous method places many restrictions on the direction of TFL sensor development, such as applying additional signal processing and/or artificial intelligence. Meanwhile, the proposed method uses amplitude demodulation to obtain the signal amplitude from the TFL sensor, and the sampling rate of the amplitude information is same to the raw TFL sensor data. The proposed method using amplitude demodulation provides ample freedom for development by eliminating restrictions on the first coil input frequency of the TFL sensor and the speed of applying the sensor to external tension. It also maintains a high measurement sampling rate, providing advantages for utilizing additional signal processing or artificial intelligence. The proposed method was validated through experiments, and the advantages were verified through comparison with the previous method. For example, in this study the amplitudes extracted by amplitude demodulation provided a sampling rate 100 times greater than those of the previous method. There may be differences depending on the given situation and specific equipment settings; however, in most cases, extracting amplitude information using amplitude demodulation yields more satisfactory results than previous methods.

• Analytical Science and Technology
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• v.22 no.6
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• pp.504-513
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• 2009

In this study, the safety of commercial herbal medicines was evaluated by determining concentration of hazardous heavy metals. 3,152 samples (244 types) purchased by individual packing unit from market in Seoul, were analyzed using ICP-MS and mercury analyzer. As a result, the content (mg $kg^{-1}$) of Pb was higher in the above-ground part (0.92) than underground part (0.43). But in case of As and Cd contents, there is slightly higher in the underground-parts (0.26, 0.13) than the above-ground parts (0.18, 0.08). There were many herbal medicines exceeding regulatory limits of Cd comparing with other metals. The levels of Hg seemed to be different between above-ground part(0.009) and underground part (0.008) but there was no sample exceeding tolerance limits. In the comparison of imported samples with domestic herbal medicines, it was shown that Pb, As, and Hg were measured highly in the imported ones, Cd was not significantly different (t-test, p<0.05). The significant correlation was observed between Pb and As (r=0.386, p<0.01) but there was no difference in other parts. The heavy metal contamination of herbal medicines measured in total amount of respective heavy metals (mg $kg^{-1}$) was high in Flos (6.241) and Caulis (2.238), and decreased in the order of Cortex (1.634), Herba (1.154), Perithecium (0.861), Rhizoma (0.828), Radix (0.825), Fructus (0.475), and was low in Semen (0.422) (ANOVA-test, p<0.05).

• Analytical Science and Technology
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• v.21 no.5
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• pp.383-391
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• 2008

International Agency for Research on Cancer (IARC) has classified it as a possible carcinogen and World Health Organization (WHO) has suggested 50 ng/mL as a guideline value for 1,4-dioxane. Considering the toxicity of 1,4-dioxane and ingestion rate of drinking water, the monitoring of 1,4-dioxane in drinking water in Nakdong river is very important. We analyzed 1,4-dioxane four times per year for the 12 samples of treated water and 4 samples of raw water in Nakdong river in Korea from 2000 to 2007 and surveyed the trend of concentrations of 1,4-dioxane. As a results of analysis, 1,4-dioxane was detected from 0.24 to 240.2 ng/mL in treated water and from 0.39 to 81.9 ng/mL in raw water from 2000 to 2007. The average concentrations are 22.68 ng/mL and 19.15 ng/mL in treated water and raw water, respectively. The detected concentrations was decreased but frequency of detection was not changed since establishment of regulation in 2004. Results of comparison of 95 percentile excessive cancer risk of 1,4-dioxane in treated and raw water were each $6.63{\times}10^{-6}$, $3.17{\times}10^{-6}$ before 2004 and $2.10{\times}10^{-6}$, $1.22{\times}10^{-6}$ after 2004. Also, comparing the detected concentration and frequency for each season, these were more detected the concentration and frequency for 1,4-dioxane in treated and raw water from winter to spring.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.57-70
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• 2009

Considerable advance has been made on research on effect of steel pipe Umbrella Arch Method (UAM) and mechanical reinforcement mechanism through numerical analyses and experiments. Due to long analysis time of three-dimensional analysis and its complexity, un-quantitative two-dimensional analysis is dominantly used in the design and application, where equivalent material properties of UAM reinforced area and ground are used, For this reason, development of reasonable, theoretical, quantitative and easy to use design and analysis method is required. In this study, both field UAM tests and laboratory tests were performed in the residual soil to highly weathered rock; field tests to observe the range of reinforcement, and laboratory tests to investigate the change of material properties between prior to and after UAM reinforcement. It has been observed that the increase in material property of neighboring ground is negligible, and that only stiffness of steel pipe and cement column formed inside the steel pipe and the gap between steel pipe and borehole contributes to ground reinforcement. Based on these results and concept of Convergence Confinement Method (CCM), two dimensional axisymmetric analyses have been performed to obtain the longitudinal displacement profile (LDP) corresponding to arching effect of tunnel face, UAM effect and effect of supports. In addition, modified load distribution method in two dimensional plane-strain analysis has been suggested, in which effect of UAM is transformed to internal pressure and modified load distribution ratios are suggested. Comparison between the modified method and conventional method shows that larger displacement occur in the conventional method than that in the modified method although it may be different depending on ground condition, depth and size of tunnel, types of steel pipe and initial stress state. Consequently, it can be concluded that the effect of UAM as a beam in a longitudinal direction is not considered properly in the conventional method.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.189-197
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• 2023

Purpose. This study aimed to compare and evaluate the shear bond strength between various temporary prostheses resin blocks fabricated by subtractive and additive manufacturing methods bonded to self-curing reline resin. Materials and methods. The experimental groups were divided into 4 groups according to the manufacturing methods of the resin block specimens and each specimen was fabricated by subtractive manufacturing (SM), additive manufacturing stereolithography apparatus manufacturing (AMS), additive manufacturing digital light processing manufacturing (AMD) and conventional self-curing (CON). To bond the resin block specimens and self-curing resin, the reline resin was injected and polymerized into the same location of each resin block using a silicone mold. The shear bond strength was measured using a universal testing machine, and the surface of the adhesive interface was examined by scanning electron microscopy. To compare between groups, one-way ANOVA was done followed by Tukey post hoc test (α = 0.05). Results. The shear bond strength showed higher values in the order of CON, SM, AMS, and AMD group. There were significant differences between CON and AMS groups, as well as between CON and AMD groups. but there were no significant differences between CON and SM groups (P > .05). There were significant differences between SM and AMD groups, but there were no significant differences between SM and AMS groups. The AMS group was significantly different from the AMD group (P < .001). The most frequent failure mode was mixed failures in CON and AMS groups, and adhesive failures in SM and AMD groups. Conclusion. The shear bond strength of SM group showed lower but not significant bond strength compared to the CON group. The additive manufacturing method groups (AMS and AMD) showed significantly lower bond strength than the CON group, with the AMD group the lowest. There was also a significant difference between the AMD and SM group.

• Journal of Korea Entertainment Industry Association
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• v.13 no.3
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• pp.213-220
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• 2019

Desire for a happy life becomes the will that man instinctively desires. In that the conditions of happiness are subjective and varied, the will of subjective desires has been studied with the attention of objective tendencies. The positive and meaningful will of life in the desire for happiness leads us to be the functionaries who act. These wills can be the driving force of a happy life, which allows one to have a hopeful reflective will in one's inner life, connecting oneself with others, and working in relationships with others. In addition, those who become lazy or lose their orientation in life can instill a will to be the main character of life, and furthermore, to give the ultimate meaning and goals of life. To understand and analyze these wills for happy lives more specifically, structural model compatibility and confirmatory factors were conducted. relatively reliable α=.855 value, the coefficient of correlation between recognition and will **p<.01, *p<.05 statistically significant measuring tool of not less than 05 was used. The study results of the structural model suitability of the factors of will and the confirmatory factor analysis showed that the model set by the researcher could reflect the characteristics of the data collected, and that the χ²(Chi-square) value was .126, which was consistent with the model by satisfying the acceptance criteria, and that the comparison of the reference values of the study model showed a relatively high level of suitability. To identify the relationship between cognitive and defined and behavioral factors of subjective will and existent will variables, the results of a verification factor analysis show that the χ²(Chi-square) value is 2.36 and the model and data are consistent with the acceptance criteria, and that the test data is consistent with the model and data set by the researcher are consistent with the model5.0 Through structural model analysis of human will, it was confirmed that the variables of subjective and existential, sensible and reflective will directly and indirectly influence and form a complex relationship. Our will is recognized as the subjective will, and the structure of the subjective will consists of the sensible and reflective will, and the relationship between the cognitive and just action elements and the subjective will of the human life and the will to exist is shown to be very meaningful, so we should conduct the education of the happy will of the emotional and just areas of life as well as the reestablishment of the cognitive educational direction that can lead to action.

• 한국노년학
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• v.39 no.4
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• pp.921-939
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• 2019

According to the social selectivity theory (SST), despite the disadvantages of life conditions, older adults experience less negative emotions because they regulate their emotions by avoiding negative stimuli or situations. Based on the SST, this study attempted to find out whether older adults are better able to regulate negative emotions than young adults in the Ultimatum Game (UG). In an UG, if the proposer proposes to distribute a portion of the money to the responder, the responder must decide whether to accept or reject it. If the responder accepts the offer, the proposer and the responder can each have their own share as proposed, but if s/he reject the offer, both get nothing. Thus, if the responder considers own economic benefits, it is a more reasonable decision to accept the unfair offer no matter how low, than to reject it. To accept an unfair offer, the responder must regulate the anger felt at the proposer. If older adults could regulate anger better than young adults, they would be less likely to reject the unfair offer than young adults. Fifty-seven olders and 60 university students participated in this study. Both the older and young adults accepted most of the fair offers. In contrast, older adults accepted unfair offers at a significantly higher rate than young adults. In addition, compared to young adults, older adults reported anger less frequently at the unfair offers. Accepting unfair offers was negatively correlated with anger report, but positively correlated with the emotion regulation measured by ERQ. The ERQ score was negatively correlated with anger report. Emotion regulation partially mediated the relationship between the age groups and acceptance of unfair offers. The present results showed that older adults accepted the unfair offers at a higher rate than young adults because they could regulate the negative emotions felt at the unfair offer better than young adults. This study provided new evidence for the claim that improving emotional regulation is a major developmental change in adulthood.

• 한국노년학
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• v.39 no.2
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• pp.199-211
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• 2019

The purpose of this study is to analyze leisure satisfaction and leisure performance according to whether elderly people are performing their preferred leisure activities. For the analysis, we used sample from the 6th (2015) panal data as Korean Retirement and Income Study(KReIS). The results of this study were as follows. First, the total data of 4,197 elderly (2,212 young-old and 1,985 old-old) were analyzed. As a result, weekday and weekend leisure time of the old-old (7.64 hours / 7.81 hours) than the young-old (6.83 hour / 7.39 hour) was increased and resting activites (over 70% of watching TV and listening to the radio) accounted for more than 80% of the both elderly leisure activities. Leisure performance were higher in old-old who did not perform preferred leisure activities during weekdays. Leisure performance on weekends was higher in old-old regardless of whether they had preferred leisure time. Average of leisure performance was high in both groups and they responded leisure satisfaction was moderate. In the case of need for leisure change, young-old was higher than oid-old regardless of preference leisure performance and day of the week. However, the responses of the both groups are closed to those that do not want to change. Based on the results of this study, it should be practiced such as develomenting program and introduction of health management system considering leisure constraints to improve leisure satisfaction and continuance of leisure activities for young-old and old-old. We also emphasize the need for a systematic survey scale that takes into account the qualitative aspects of leisure activities as well as the subjective factors influencing leisure participation.