• Research in Mathematical Education
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• v.13 no.2
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• pp.151-170
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• 2009

This study reports a research which was conducted on how frequently and where the students use the unit circle method while dealing with trigonometric functions in solving the trigonometry questions. Moreover, the reasons behind the choice of the methods, which could be the unit circle method, the ratio method, or the use of trigonometric identities, are also investigated to get an insight about their understanding. In this study, the relationship between the students' choices of methods in solving questions is examined in terms of instrumental or relational understanding. This is a multi-method research which involves a range of research strategies. The research techniques used in this study are test, verbal protocol (think aloud), and interview. The test has been applied to ten tenth grade students of a public school to get students' solution processes on the paper. Later on, verbal protocol has been performed with three students of these ten who were of the upper, middle and lower sets in terms of their performance in the test. The aim was to get much deeper data on the students' thinking and reasoning. Finally, interview questions have been asked both these three students and other three from the initial ten students to question the reasons behind their answers to the trigonometry questions. Findings in general suggest that students voluntarily choose to learn instrumentally whose reasons include teachers' and students' preference for the easier option and the anxiety resulting from the external exam pressure.

• Journal of Labour Economics
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• v.35 no.1
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• pp.111-136
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• 2012

This paper investigates effects of family size on private tutoring expenditures, using a data set drawn from the Korean Longitudinal Survey of Women & Families (KLoWF). To deal with endogeneity of family size, the paper employs an instrumental variable (IV) method in which the sex of the first-born of the family is used as an IV. The results suggest that quantity-quality trade-offs of children within a family function in a way that varies by the sex of the child. While the effect of an increase in family size on private turoring expenditures of a second-born daughter is negative, the effect for a second-born son is indeterminate. The result for daughters implies that high costs of raising a child are likely to explain low birth rates of Korea.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.11 no.2
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• pp.166-176
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• 2004

Purpose: The purpose of this study was to identify the factors that affect depression among elderly people with, and without, dementia. Method: The participants were 903 people who were 65 or older and resided in Sungnam City. Data were collected from April to July 2002 using a questionnaire. The collected data were analyzed using descriptive statistics and hierarchical multiple regression aided by SPSS/PC. Result: The variables at the final step of the regression equation accounted for 28.2% of variance in the dementia group, 21.4% in the group with suspicious dementia, and 18.9% in the normal group. The multiple regression analysis revealed that ADL and instrumental support were related significantly to depression in the dementia group. Self-rated health, IADL, social activity support, and instrumental support were significantly related to depression in the group with suspicious dementia. In the normal group, education, self-rated health, and living arrangement with family were significantly related to depression. Conclusion: Social support and health condition are important to decrease depression in elderly people with dementia.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.16.1-16.9
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• 2014

Objectives Rapid increase in engineered nanoparticles (ENPs) in many goods has raised significant concern about their environmental safety. Proper methodologies are therefore needed to conduct toxicity and exposure assessment of nanoparticles in the environment. This study reviews several analytical techniques for nanoparticles and summarizes their principles, advantages and disadvantages, reviews the state of the art, and offers the perspectives of nanometrology in relation to ENP studies. Methods Nanometrology is divided into five techniques with regard to the instrumental principle: microscopy, light scattering, spectroscopy, separation, and single particle inductively coupled plasma-mass spectrometry. Results Each analytical method has its own drawbacks, such as detection limit, ability to quantify or qualify ENPs, and matrix effects. More than two different analytical methods should be used to better characterize ENPs. Conclusions In characterizing ENPs, the researchers should understand the nanometrology and its demerits, as well as its merits, to properly interpret their experimental results. Challenges lie in the nanometrology and pretreatment of ENPs from various matrices; in the extraction without dissolution or aggregation, and concentration of ENPs to satisfy the instrumental detection limit.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.24 no.1
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• pp.1-15
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• 2011

Objective : To establish the fundament for EBM of Traditional Korean Medicine, the papers on Bangpungtongseong-san (Fangfengtongsheng-san) frequently used in medical institutions of Traditional Korean Medicine were analyzed through researching domestic and international papers. Methods : The papers were classified by the registration of domestic or international journals, the year of publishment, experimental fields and the kinds of studies on biological activities. Results : Among 324 volumes of papers on Bangpungtongseong-san (Fangfengtongsheng-san), 38 volumes were selected according to selective criteria. 18 volumes were published in domestic journals, 20 volumes were in Japanese journal. The papers on instrumental analyses reported the quantification of standard compounds of herbal medicines in Bangpungtongseong-san (Fangfengtongsheng-san) using HPLC method. The papers on biological activities of Bangpungtongseong-san (Fangfengtongsheng-san) showed inhibitory effect to obesity, arteriosclerosis, allergic response, inflammation, pain, hyperlipidemia, hypertension, atopy, diabete mallatus and improvement of gastrointestinal activity and cerebral blood circulation. Among biological activities, papers on anti-obesity effect were reported mostly. Conclusions : Further studies including anti-obesity activity need to be preceeded to establish the fundament for EBM of Bangpungtongseong-san (Fangfengtongsheng-san).

• Speech Sciences
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• v.12 no.2
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• pp.89-99
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• 2005

The purpose of the present study were (1) to assess differences in tongue performances and speech intelligibility between normal and dysarthric speakers; and (2) to analyze the possible interrelationships between tongue strength, range of motion, and speech intelligibility in dysarthric patients. In order to measure maximum strength of anterior and lateral tongue strength, a force transducer has been designed. And a ruler was used for guaging range of motion. 'Word intelligibility test' was administered to each group. The results were analyzed by a quantitative statistical method(t test, Pearson product- moment correlation, and one-way ANOVA). The results were as follows; (1) dysarthric speakers showed significantly poorer performance than the normal in the tongue strength, range of motion, and speech intelligibility tasks; (2) the correlation between speech intelligibility and instrumental tongue performance was high in the dysarthric group; and (3) instrumental assessment was coincide with perceptual judgement of dysarthric tongue performance. The present investigation demonstrated that tongue weakness is causally related to articulation deficits in dysarthric. The clinical use of the force transducer would help a speech pathologist to quantify the degree of tongue weakness.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.14 no.2
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• pp.221-229
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• 2007

Purpose: To investigate the instrumental activities of daily living (IADL), leg muscle strength, cognitive and visual functions according to the participants' demographic characters and experiences of falling in Korean elder who are residents in the community. Method: Data were collected from 351 participants aged 65 or more, who were ambulatory, A structured questionnaire and several physical function measurements were used to collect the data which were analyzed using the SAS program. Results: The participants' IADL scores were significantly different according to their age, educational level and living situation. The leg muscle strength of the elders were significantly different according to gender and age, and were also related the risk of falling. Cognitive scores were significantly different according to gender, age, education level and marital status. Visual acuity and depth perception were significantly different according to age, education level, and marital status. Conclusion: Demographic variables and experience of falling were identified as variables related to IADL, leg muscle strength, cognitive and visual function of elders. Further study with a larger and nation-wide sample is needed to identify the variables related to the physical and cognitive functions of elders.

• The Journal of Engineering Geology
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• v.5 no.1
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• pp.45-58
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• 1995

A probabilistic seismic risk in the Korean Peninsula is calculated from the instrumental eaathquake data. For the purpose, an instrumental earthquake catalogue since 1905 m which parameters are readjusted to have uniformity and homogeneity in description is cornpiled through the review of all available data. The maximum potential earthquake expected in the Korean Peninsula for 100, 1000, and 4000 years are estimated to be 6.3, 7.2 and 7.8 in magnitude, respectively, from Gumbel's extreme value theory. In addition, contour rnaps representing the maximum ground acceleration expected for 100 and 1000 years are prepared using the return period method. Seismic hazart] curves in which maximum ground acceleration expressed in terms of probability of occurrence are also presented for the major populated areas.

• Journal of the Korean Chemical Society
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• v.56 no.3
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• pp.357-362
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• 2012

5-Nonylsalicylaldoxime and salicylaldehyde are two derivatives of phenolic compounds which are very applicable materials in industries. Formerly the formylation of phenolic derivatives were carried out by Rimer-Tiemann method. In this work both of these two materials were synthesized by magnesium meditated formylation technique and their structural characterizations were compared by instrumental analysis technique. In order to achieve a selectively orthoformylated product, the hydroxyl group of nonylphenol (or phenol) was first modified by magnesium methoxide. The nonylphenol magnesium salt was then formylated by paraformaldehyde. The oximation reaction was finally applied to the prepared nonylsalicylaldehyde magnesium salt by liquid extracting via water and acid washing and other extractions. The solvent was finally removed by evaporation under reduced pressure. Some instrumental analysis such as $^1H$-NMR, GC/MS and FT-IR spectra were taken on the product in order to interpret the reaction characterization quantitatively and qualitatively. The formaldehyde and oxime functional groups of two compounds were investigated through $^1H$-NMR and FT-IR spectra and were compared. The yield of methoxilation was very good and the yields of formylation and oximation reactions were about 90%and 85% respectively. The orthoselectivity of formylation reaction were evaluated by comparing of the relevant spectra. The GC/MS spectra also confirmed the obtained results.

• Journal of Educational Research in Mathematics
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• v.24 no.3
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• pp.311-331
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• 2014

For preservice teachers' instrumental-to-relational pedagogical content knowledge transformations, this research designed several didactical tasks based on Kinach's cognitive strategies. The researcher identified preservice teachers' understanding about what is a definition and how to teach it. By challenging their fixed ideas about definitions, the researcher could motivate them to embrace the new teaching approach which guides reinvention of definitions. The PCK development was not the simple process of filling their tabular rasa PCK with theories of mathematics education, but the dialectical process of identifying, challenging, changing and extending preservice teachers' existent PCK. This research will contribute to explore new directions of mathematics teachers' PCK development and the method of teacher education.