• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.313-321
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• 1996

Our laboratoy has been participated in Proficiency Analytical Testing (PAT) program which is operated by the Americal Industrial Hygiene Association in cooperation with the National Institute for Occupational Safety and Health (NIOSH). The program is designed to assist a laboratory improve its analytical performance by providing samples on a quarterly basis, evaluating the results, and providing reports on how well the laboratory performed. Evaluation of the results reported here covers five rounds of the PAT program (round 121~round 125). The way a laboratory is evaluated by PAT program is as follows: 1) There is no overall proficiency rating given to a laboratory. 2) A proficiency rating is given for each type of analyze (i.e., metals, silica, asbestos, solvents) that a laboratory analyzed. 3) Proficiency is rated acceptable ("A") if Z score lies between -3 and +3, and unacceptable if Z score is either higher than +3 ("H") or lower than -3 ("Lo"). Z score = (reported data - reference value) / standard deviation 4) For a laboratory to be rated proficient it must either have had no outliers over the most recent two rounds or of the samples actually analyzed over the past year (past four rounds), 75 % or more of the analyze sample results must be acceptable. According to the above rating criteria of PAT program, performance of metals including cadmium, lead, chromium and zinc, and asbestos sample analyses were rated acceptable ("A"). For silica analyses, all samples except one out of four samples in round 122 was rated high("H") were acceptable showing 95 % of ing 95 % of acceptance rate (19/20) throughout the rounds. Analyses of organic solvents were done on 52 samples in 9 types including methanol(MOH), 1,1,1-trichloroethane(MCM), tetrachloroethylene(PCE), trichloroethylene(TCE), benzene(BNZ), o-xylene(OXY), toluene(TOL), chloroform(CFM), 1,2-dichloroethane(DCE). All samples analyzed were rated acceptable except 2 samples that were rated high; one out of each four MCM and TCE samples in round 121, and one that was low out of four o-xylene analyses in round 122 indicating 94 % of acceptance rate(49/52) throughout the rounds. According to the laboratory rating criteria, our laboratory is rated proficient so far for all types of contaminants.

• The Korean Journal of Blood Transfusion
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• v.23 no.2
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• pp.162-168
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• 2012

Background: Potassium, the most common cation in the intracellular space, plays a critical role in our physiology. Potassium imbalance may cause life-threatening problems, ranging from general weakness to cardiac arrest due to ventricular fibrillation. For emergency physicians, detection of such derangement within a short period of time is of critical importance. In this study, we wanted to determine whether analysis of whole blood samples can be used as a screening tool for potassium imbalance by comparative analysis of whole blood and serum samples. Methods: Two samples were drawn from 227 patients. The whole blood sample was taken from the radial artery and contained in a commercially available arterial blood collection syringe with a lithium-heparin coating. The serum sample was contained in a commercially available vacuum bottle in a non-additive silicone coated tube and transported to the laboratory. The study population was divided into three groups, patients with normal whole blood potassium, patients with decreased whole blood potassium, and patients with elevated whole blood potassium. Potassium levels for each group were coupled with serum potassium levels and compared. Results: No significant difference in potassium values was observed between whole blood and serum samples (P<0.05). Strong associations were observed among the three groups (normal range, hypokalemia, and hyperkalemia group). Compared to the normal group (r=0.851), the hyperkalemia group showed a stronger association between variables (r=0.897), and the hypokalemia group showed a weaker association (r=0.760). Their correlation coefficients were highly significant (P<0.05). Conclusion: Our study illustrates that point-of-care testing using whole blood with whole blood can be a reliable screening tool when treating patients with suspicious potassium abnormality, especially in hyperkalemia patients.

• The Journal of Korean Academic Society of Nursing Education
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• v.22 no.4
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• pp.549-558
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• 2016

Purpose: The purpose of this study was to develop and validate a Nursing Competency Scale in Simulation (NCSS) for nursing students. Methods: A preliminary version of the NCSS of 14 items was derived from the literature. A panel of seven experts reviewed the preliminary version for content validation and developed 15 items scale. A convenient sample of 195 nursing students completed the survey and two evaluators measured the performances of nine teams in a simulation scenario with NCSS. The data were analyzed using exploratory factor analysis, descriptive statistics, independent t-test and Cronbach's alpha. Intraclass correlation coefficient (ICC) was used in order to estimate the degree of inter-rater reliability. Results: An exploratory factor analysis demonstrated that two factor structures of the NCSS explained 51.1% of the total variance. Two factors were named psychosocial skills and cognitive and psychomotor skills. The mean scores of NCSS between third and 4th grade were significantly different providing support for its known-group validity. Cronbach's alpha was .90 and ranged from .79 to .88. The overall ICC for inter-rater agreement was 0.89 (95% CI 0.03 to 0.98). Conclusion: This scale shows preliminary evidence for validity and reliability. It could be a useful instrument for measuring learning outcome in simulation for nursing students' clinical competency.

• Safety and Health at Work
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• v.11 no.1
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• pp.61-70
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• 2020

Background: This study aims to assess whether the TSI PortaCount (Model 8020) is a measuring instrument comparable with the flame photometer. This would provide an indication for the suitability of the PortaCount for determining the workplace protection factor for particulate filtering facepiece respirators. Methods: The PortaCount (with and without the N95-Companion^TM) was compared with a stationary flame photometer from Moores (Wallisdown) Ltd (Type 1100), which is a measuring instrument used in the procedure for determining the total inward leakage of the particulate filtering facepiece respirator in the European Standard. Penetration levels of sodium chloride aerosol through sample respirators of two brands (A and B) were determined by the two measuring systems under laboratory conditions. For each brand, thirty-six measurements were conducted. The samples were split into groups according to their protection level, conditioning before testing, and aerosol concentration. The relationship between the gauged data from two measuring systems was determined. In addition, the particle size distribution inside the respirator and outside the respirator was documented. Linear regression analysis was used to calculate the association between the PortaCount (with and without the N95-Companion^TM) and the flame photometer. Results: A linear relationship was found between the raw data scaled with the PortaCount (without N95-Companion^TM) and the data detected by the flame photometer (R² = 0.9704) under all test conditions. The distribution of particle size was found to be the same inside and outside the respirator in almost all cases. Conclusion: Based on the obtained data, the PortaCount may be applicable for the determination of workplace protection factor.

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.146-150
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• 2015

PURPOSE. This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading. MATERIALS AND METHODS. Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test. RESULTS. The mean and standard deviations of the failure load were $1,170.1{\pm}90.9$ N for EV design and $1,450.4{\pm}175.7$ N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples). CONCLUSION. There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5
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• pp.42-52
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• 2010

This research analyzed the overall issues pertaining to the questions that appear in the professional landscape architect screening system to assess 1he recognition of test-takers when it comes to the test questions in terms of the question objectivity, appropriateness, difficulty level and so forth The purpose of this is to present a set of recommendations so that the screening system can he improved and the professional landscape architect screening system consolidate its position. This in turn can help the professional landscape architect qualification process consolidate its position and improve the status of the landscape area in the industrial field. The research of this study was conducted for the all-round development of Landscape Architecture. The research method was divided into two stages, and a group of experts was leveraged to study subjects that are tested and subjects allocated. A survey was conducted of candidates and certification holders to assess the questions that appear in the test in terms of their level, objectivity, difficulty level, tendency of questions and so forth. Firstly, the study demonstrated that the subjects tested in the professional landscape architect test are different from the testing subjects that are suggested in the enforcement ordinance of the National Technical Professional Law. In addition, o1her problems include the overvaluation of a subject for testing, a lack of objectivity in testing, and difficulty level adjustment of questions. One main reason for many of these kinds of problems is that the questions appeared without thorough review and there is a lack of management concerning the members of the commtittee that develops the question. Accordingly, to make up for these problems, a viable screening system such as the reorganization of subjects that are tested, assigning suitable subjects, securing of question objectivity, and difficulty level of developed questions are necessary.

• Communications for Statistical Applications and Methods
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• v.19 no.1
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• pp.47-55
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• 2012

The newly revised bioequivalence guideline of Korea allows the add-on test since July 1, 2008 when the initial bioequivalence trial fails to show the equivalence of two drugs. The statistical model of the add-on test and its two stage testing procedures are discussed. Some statistical points of consistency test in the add-on test are considered and the issue on the sample size of add-on test is discussed. Some reasonable alternative like Japan's guideline for bioequivalence studies is recommended to secure the proper use of an add-on study through some simulation studies.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.270-277
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• 2013

PURPOSE. This study was aimed to determine the effect of two chemically distinct denture cleansers and water on the surface hardness of acrylic and silicone based soft denture liners at various time intervals. MATERIALS AND METHODS. Two commonly used commercial resilient liner material were selected based on their chemical composition (silicone- and acrylic-based soft liners) for this investigation. 120 cylindrical specimens were made of $15mm{\times}10mm$ dimensions (according to ASTM: D-2240-64T) in a custom made metal mold. All specimens were stored in artificial saliva throughout the study. Forty specimens were cleansed daily in 0.5% sodium hypochlorite solution; forty were cleansed in sodium perborate and remaining forty specimens were daily rinsed in water. Testing was done at 1 week, 1 month, 3 months and 6 months for surface hardness using a Shore A Durometer. A mean of 3 reading for each sample was subjected to one-way ANOVA, Post Hoc test and pair-t test for statistical analysis. P values of less than 0.05 were taken as statistically significant. RESULTS. Surface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Minor changes were observed between control, sodium hypochlorite and sodium perborate groups with time. Greater change was observed in surface hardness of acrylic-based soft denture liners as compared to silicone-based soft liners for all groups, as time progressed. CONCLUSION. Silicone-based soft denture liners performed significantly better in all cleansing treatments than acrylic-based soft denture liners.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.5
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• pp.412-417
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• 2013

Analytical modeling of photovoltaic power systems has been receiving significant attentions in recent years in that it is easy to apply for prediction of its dynamics and fault detection and diagnosis in advanced engineering technologies. This paper presents a novel probabilistic modeling approach for such power systems with a big data sequence. Firstly, we express input/output function of photovoltaic power systems in which solar irradiation and ambient temperature are regarded as input variable and electric power is output variable respectively. Based on this functional relationship, conditional probability for these three random variables(such as irradiation, temperature, and electric power) is mathematically defined and its estimation is accomplished from ratio of numbers of all sample data to numbers of cases related to two input variables, which is efficient in particular for a big data sequence of photovoltaic powers systems. Lastly, we predict the output values from a probabilistic model of photovoltaic power systems by using the expectation theory. Two case studies are carried out for testing reliability of the proposed modeling methodology in this paper.

• Journal of Families and Better Life
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• v.33 no.5
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• pp.37-53
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• 2015

The purpose of this study is to examine the differences in perceived time pressure between employed and non-employed married women in Korea. The sample of married couple from the Korean Time Use Survey 2009 (n = 6,948 couple diaries) was used to examined the difference in the level of perceived time pressure over the life cycle of two group. This study also investigated the married women's time use, husband's time use as well as hour of domestic outsourcing and whether such factors are associated with lowering perceived time pressure of married women. Results showed employed wives felt almost 3 times more time pressed than non-employed wives, and the gap mostly remained over different life cycles. Total work hours were associated with increasing the time pressure of both groups of women, while regenerating time was associated with ameliorating time pressure. The result suggests that the time pressure gap between employed and non-employed wives can be partly due to the relative length of total labor hours and regenerating time among the two groups. Ordered logit analysis revealed that husband's paid work hours were not associated with wive's feeling rushed, but husband' unpaid work hours were positively linked with time pressure of their wives. Results indicated if employed or non-employed wives are feeling very busy, there is a high chance that husband might give them some help. We found employed wives spend more hours on housework outsourcing, and purchasing goods for housework was not associated with lowering the feeling of pressure of employed wives. There were both similarity and difference in factors associated with women's feeling pressed among employed and non-employed wives. It implies that social process and it's strategies to alleviate the time pressure can be different by women's employment status.