• Journal of Sensor Science and Technology
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• v.9 no.4
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• pp.288-296
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• 2000

Thin-film chromel-alumel multijunction thermal converters with a low output resistance of $64{\sim}85\;{\Omega}$ showed approximately the square law-dependent input-output relation. The voltage responsivities were very low with $0.34{\sim}0.67\;V/W$ in air and $1.15{\sim}1.48\;V/W$ in vacuum, respectively, and the ac-dc voltage transfer error was very large with about +340 ppm in the frequency range of $40\;Hz{\sim}10\;kHz$ in the case of 1 V-input sinewave rms voltage. It can be concluded that the large transfer error of the thermal converter was mainly caused by the low voltage responsivity and the large heat loss due to low output resistance, which implies that the optimization for small ac-dc transfer error is required.

• International Journal of Highway Engineering
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• v.17 no.5
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• pp.25-31
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• 2015

PURPOSES: The objective of this study is to analyze the relationship between the FWD back-calculated modulus and dynamic modulus of asphalt layers for existing asphalt pavements. METHODS: To evaluate the dynamic modulus of the asphalt mixture in the existing and new asphalt layers, the uniaxial direct tension test was conducted on small asphalt specimens obtained from the existing asphalt-covered pavements. A dynamic modulus master curve was estimated by using the uniaxial direct tension test for each asphalt layer. The falling weight deflectometer (FWD) testing was conducted on the test sections, and the modulus values of pavement layers were back-calculated using the genetic algorithm and the finite element method based back-calculation program. The relationship between measured and back-calculated asphalt layer moduli was examined in this study. The normalized dynamic modulus was adopted to predict the stiffness characteristics of asphalt layers more accurately. RESULTS: From this study, we can conclude that there is no close relationship between dynamic modulus of first layer and back-calculated asphalt modulus. The dynamic moduli of second and third asphalt layers have some relation with asphalt stiffness. Test results also showed that the normalized dynamic modulus of the asphalt mixture is closely related to the FWD back-calculated modulus with 0.73 of R square value. CONCLUSIONS: The back-calculated modulus of asphalt layer can be used as an indicator of the stiffness characteristics of asphalt layers in the asphalt-covered pavements.

• Korean Journal of Remote Sensing
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• v.34 no.4
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• pp.625-638
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• 2018

In this paper, we derive i) a function to estimate snow cover fraction (SCF) from a MODIS satellite image that has a wide observational area and short re-visit period and ii) a function to determine snow depth from the estimated SCF map. The SCF equation is important for estimating the snow depth from optical images. The proposed SCF equation is defined using the Gaussian function. We found that the Gaussian function was a better model than the linear equation for explaining the relationship between the normalized difference snow index (NDSI) and the normalized difference vegetation index (NDVI), and SCF. An accuracy test was performed using 38 MODIS images, and the achieved root mean square error (RMSE) was improved by approximately 7.7 % compared to that of the linear equation. After the SCF maps were created using the SCF equation from the MODIS images, a relation function between in-situ snow depth and MODIS-derived SCF was defined. The RMSE of the MODIS-derived snow depth was approximately 3.55 cm when compared to the in-situ data. This is a somewhat large error range in the Republic of Korea, which generally has less than 10 cm of snowfall. Therefore, in this study, we corrected the calculated snow depth using the relationship between the measured and calculated values for each single image unit. The corrected snow depth was finally recorded and had an RMSE of approximately 2.98 cm, which was an improvement. In future, the accuracy of the algorithm can be improved by considering more varied variables at the same time.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.1077-1081
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• 2010

In this work, we report the diagnostic relations among some primary pulse conditions such as the floating/sunken, deficient/forceful, large/fine, and the long/short pulses. For this purpose, we carried out a clinical test, in which 11 Oriental medical doctors had participated to diagnose the pulses for 1566 healthy subjects. The subjects were divided into 11 subgroups and each subgroup was allocated to an individual doctor. It resulted in that, for 847 subjects (54%), two or more than two pulse conditions were felt simultaneously, for which we counted the frequency of the pairs of the pulse conditions. For the statistical analysis, we used a Chi-square test. As a result, at high frequency, the forceful, large, and the long pulses were diagnosed in pairs or in their triplet, and a similar close relation was found between the deficient, fine, and the short pulses. The pairwise diagnoses of the pulse conditions between the forceful, large, and the long pulses, and between the deficient, fine, and the short pulses imply their close relatedness in clinics. This result is supported by the theory of deficiency/excess syndromes. Moreover, we show that the close relatedness among the pulse conditions can be understood in terms of the geometric features of the radial artery near the prominent bone. This is the first work which reports the relatedness between the primary pulses by an objective clinical test.

• Journal of the Mineralogical Society of Korea
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• v.2 no.1
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• pp.26-36
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• 1989

Clinopyroxene in the Geodo mine belongs to diopside-hedenbergite series. It is widely distributed throughout the mine area together with garnet and is also closely related with Fe-mineralization. Clinopyroxenes in the Geodo mine including two samples from the sangdong and Ulchin Mines are studied using polarized microscope, EPMA, XRD, and IR spectroscopy for occurrence, chemistry, structure, and crystal chemistry. Especially, variations in unit-cell parameters are examined in relation with the substitution scheme between Fe and Mg cations. Clinopyroxenes in the Geodo mine occur in both endoskarn and exoskarn zone. It is mostly anhedral to subhedral with fine- to medium-grained in texture, but some have bigger crystals of short prismatic or columnar habits. Clinopyroxene occurs as monomineralic or is associated with mostly garnet and sometimes with actinolite, magnetite, epidote, and chlorite. Chemical analysis reveals that the Geodo clinopyroxene is diopsidic in composition (Di: 65-96%). This fact is in good contrast with garnet chemistry showing mostly andraditic (An: 41-82%). Especially, clinopyroxene coexisting with magnetite belongs to nearly end member diopside (Di: 97-99%). Thus, diopside-andradite pair indicates that Geodo skarns were formed under the reduced environment. X-ray diffraction analysis shows unit-cell parameters vary with increase of Fe contents: a = 9.765-9.838$\AA$, b = 8.943-9.020$\AA$, c= 5.240-5.253$\AA$.$\beta$ = 105.70-104.83$^{\circ}$, and V =440.64-448.19$\AA$3. It is noted from the least square regression that a, b and V increase linearly with increase of Fe content, while $\beta$ slightly decreases and c remains nearly unchanged as change in Fe content. These trends are to difference between synthetic and natural clinopyroxenes. This fact is also recognized in IR spectra which show a slight shift of several absorption bands toward lower wavenumber region with increasing Fe content.

• Food Quality and Culture
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• v.3 no.1
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• pp.20-26
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• 2009

The purpose of this study was to investigate the characteristics of dining-out customers by their behaviors based on geographical regions and visiting days in relation to restaurant attraction at ski resorts in Korea. The data were collected from six ski resorts. Three of the ski resorts were located in Kyunggi Province close to a metropolitan area, namely Seoul. The other three resorts were located in Kangwon Province, which is considered to be distant from the Seoul metropolitan area. A total of 599 usable questionnaires were utilized in the data analysis. Descriptive statistics and a cross tabulation analysis with chi square were used to examine the demographic characteristics of the respondents and the significant differences between geographical regions as well as between weekdays and weekends. The responding customers consisted of 57.3% (n=343) males and 42.7% (n=256) females. With respect to age, 15.5% were less than 20 yr., 44.6% were $20{\sim}30$ yr., and 28.0% were $30{\sim}40$ yr. The most recognizable occupations were student (32.9%) followed by office worker (33.2%). Twenty-seven percent of the respondents had less than one year of skiing experience and the majority (32.9%) had more than $1{\sim}3$ yr of experience. The major findings obtained from this study include statistically significant differences in the customers' demographical characteristics of age, occupation, skiing experience, and residential area according to the geographical regions of Kyunggi Province and Kangwon Province (p<0.05). All six of the customers' behavioral attributes, including transportation, reason to visit, staying days, purpose of visit, spending expenses, and usage of discount programs, showed significant differences between geographical groups (p<0.05). Finally, restaurant attraction was associated with the purpose of visiting and spending expenses by customers at the ski resorts (p<0.001).

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.77-84
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• 1988

This experiment was conducted to investigate the morphological and structual characters and the dry weight of plant (DW/pl.) concerned vegetational structure of orchardgrass pastures by the times of year, from 1 year to 7 year previous, 1986 through 1980, alternately. This experiment was carried out on the experimental fields of Yonsei University. The results are summarized as follows: 1. Population density (PD) was extremely decreased by the times of year. 2. Pasture productivity was highest at 3 year old pasture, was lowest at 5 year old pasture and was recovered at 7 year old pasture. 3. Recovery of pasture productivity was followed the increase of dry weight of plant (DW/pl.) and number of tillers per plant (NT/pl.). 4. The population density of 7 year old pasture was 14 plants per square meter. 5. The number of tillers per plant (NT/pl.), dry weight of plant (DW/pl.) piant length (PL), and plant size (PS) was frequently showed the highest values by the times of established year. 6. The stubble diameter (DIA), stubble area (SB), plant size (PS), distance between neibour plant (DIS) and leaf alea index (LAI) was increased according to the times of year. 7. The dry weight of plant (DW/pl.) was positively significant correlations with the number of tillers per plant (NT/pl.) all of the established pastures, but the dry weight of a tiller (WT) was tended to increase of correlations with the dry weight of plant (DW/pl.) by the times of year. 8. Differences between morphological and structual characters was recognized according to the times of year.

• Restorative Dentistry and Endodontics
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• v.39 no.3
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• pp.164-171
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• 2014

Objectives: Designing in situ models for caries research is a demanding procedure, as both clinical and laboratory parameters need to be incorporated in a single study. This study aimed to construct an informative guideline for planning in situ models relevant to preexisting caries studies. Materials and Methods: An electronic literature search of the PubMed database was performed. A total 191 of full articles written in English were included and data were extracted from materials and methods. Multiple variables were analyzed in relation to the publication types, participant characteristics, specimen and appliance factors, and other conditions. Frequencies and percentages were displayed to summarize the data and the Pearson's chi-square test was used to assess a statistical significance (p < 0.05). Results: There were many parameters commonly included in the majority of in situ models such as inclusion criteria, sample sizes, sample allocation methods, tooth types, intraoral appliance types, sterilization methods, study periods, outcome measures, experimental interventions, etc. Interrelationships existed between the main research topics and some parameters (outcome measures and sample allocation methods) among the evaluated articles. Conclusions: It will be possible to establish standardized in situ protocols according to the research topics. Furthermore, data collaboration from comparable studies would be enhanced by homogeneous study designs.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.5 s.153
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• pp.807-817
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• 2006

The purpose of this study was to investigate the buying behavior of sports apparel brand in relation to the involvement of specific professional football teams. A total of 256 adults in their 20s and 30s who residing in Seoul, Suwon, Inchon, and Daejeon completed questionnaires. Data were analyzed by using SPSS 11.0. Major statistical methods were frequency analysis, t-test and Chi square analysis. The results of this study were as follows; 1. The high involvement group of the specific professional football team showed a higher degree in the recognition, the preference, and the buying intention on sports apparel brands than the low involvement group did. Results showed statistically significant differences in responses to preferred items and store types between the low- and high involvement group. 2. With regard to the preference of sponsored apparel brands and the number of own items according to the preference of specific professional football teams, the group who preferred FC Seoul and Suwon Samsung Bluewings had a higher preference and own more items than the less preferred group did. 3. Male respondents were found to have a higher degree in the recognition, the preference and the buying intention than female respondents were. Also, there were differences in responses to a preferred store type between males and females.

• Korean journal of food and cookery science
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• v.24 no.3
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• pp.294-303
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• 2008

The purpose of this study was to investigate middle school students` perceptions on foodborne illness prevention in relation to their personal hygiene practices. The survey was administered in July, 2007 at one middle school, with a total of 390 students participating. The self-completed questionnaire consisted of several questions regarding the students` awareness of foodborne illness, perceptions of foodborne illness prevention, and personal hygiene practices. T-tests were used to identify the differences in their perceptions of foodborne illness prevention based on gender and Chi square tests were used to identify the relationships between their perceptions of foodborne illness prevention and personal hygiene practices. Eight percent of the respondents experienced foodborne illness at least once a year and 33.8% of them have stopped eating certain foods due to anxiety towards foodborne illness. The students perceived school foods (26.0%) and street foods(17.9%) as the main sources of foodborne illness, and dairy products(20.0%) and fresh fish (19.7%) were considered foods having the greatest potential for causing foodborne illness. Many students were aware of Escherichia coli O157(43.1%) and Hepatitis A(23.3%), but only a few recognized Clostridium botulinum(4.1%) and Salmonella(7.9%), even though these are major foodborne illness-causing pathogens. The students considered foodborne illness prevention very important(mean = 4.33); also, the results showed that many washed their hands 3-4 times (34.1%) and 5-6 times(29.2%) per day. Hand washing frequency was significantly related to the perceived importance of personal hygiene practice as well as to education on safety and sanitation. However, the students` perception on the importance of personal hygiene practices were not significantly different based on having received safety and sanitation education. Ultimately, these results will be used to develop guidelines for effective education on safety and sanitation.