• Journal of the Korean Graphic Arts Communication Society
• /
• v.25 no.1
• /
• pp.43-52
• /
• 2007

Offset printing is one of the well known printing technique of lithographic process and consists of image area and 'non-image area on a flat image carrier. The surface tension of dampening water can be controlled by adding IPA after mixing of raw water and etching solution. The etching solution contains a surfactant for reducing surface energy, a clean agent for non-imaging area, wetting agent for protecting non-imaging area from oil components like ink and also an emulsifying agent for controlling emulsification. In this study, the present situation of dampening water maintenance has examined by collecting dampening water using at domestic companies. The pH related to dampening water, conductivity, contact angle, emulsification curve are measured to define the current situation of dampening water control of each companies and to analyze the relationship among measured properties. In the study most of companies among 16 printing companies tested controlling dampening water through pH value. However, the quality of printing has varied depending upon conductivity, contact angle, IPA content, and emulsification value. The control of dampening water should be carry at the state of the standard when adding proper ratio of etching solution. It would be more effective when pH or conductivity control carries out in parallel with controlling dampening water. Therefore the concept that pH5.5 is correct is based concept. Based on these initial tests it is defined that the standardization of dampening water control is required.

• School Mathematics
• /
• v.15 no.4
• /
• pp.995-1013
• /
• 2013

The purpose of this paper was to investigate mathematics teachers' mathematical content knowledge about quadratic curves. Three components of mathematical knowledge are needed for teaching: (i) knowing school mathematics, (ii) knowing process of school mathematics, (iii) making connections between school mathematics and advanced mathematics. 24 mathematics teachers were asked to perform 10 questions based on mathematics curriculum. The results showed that mathematics teachers had some difficulties in conic section definitions and eccentricity definitions of ellipse and hyperbola. And they also got difficulty in Dandellin sphere proof of the equivalence of conic section definitions and quadratic curve definitions. Especially, no one answered correctly to the question about the definition of eccentricity. The ratio of correct answer for the question about constructing tangent lines of quadratic curves is less than that for the question about the applications of the properties of tangent lines. These findings suggests that it is needed that to provide plenty of opportunities to learn mathematical content knowledge in teacher education programs.

• Journal of Korea Technology Innovation Society
• /
• v.16 no.1
• /
• pp.303-322
• /
• 2013

A relevance of supporting business of technology financing for technologically innovative SMEs is strongly required for its continuous expansion and development. This study analyzes empirically whether the selection of recipient firms from technology financing have been performed in accordance with its objectives and purposes. Results show that the probability of receiving technology financing is more likely to increase with higher technology rankings and higher operating income ratio. On the other hand, the probability of obtaining financing might be decreased gradually, as the size of capital and age of the firm are increasing. Results also show that technology rankings and firm's major characteristics are found to affect significantly on the decision-making of technology financing. Several useful comments are suggested to improve the relevance of the technology financing since the correct classification rate, which explains the appropriateness of the model, is not at high level. In addition, technology rankings are not uncorrelated with the amount of financing in regression analysis. These research results will contribute to ensure the appropriateness and credibility of the technology financing decision-making.

• Journal of Nutrition and Health
• /
• v.42 no.4
• /
• pp.327-337
• /
• 2009

University students tend to have various dietary problems including undesirable dietary behaviors, inadequate intakes of nutrients and biased habits of liquid consumption. This study was conducted to find dietary behaviors (n = 357) by questionnaire survey and to examine dietary nutrient intakes (n = 60) and liquid consumption (n = 853) by food record method for 3-days among university students attended in K University of Chungnam province in Korea. Most subjects lived in the dormitory or self-boarding house, and they skipped breakfast most frequently and took breakfast most irregularly among three meals. Dietary mean intakes of energy, Ca, vitamin B2 and folate were lower than the KDRI (37-85%), and those of males were poorer than those of females. Ratios of energy intake among three meals and snacks were not distributed evenly, so the mean energy intake from snacks was higher and that from breakfast was lower than the ideal ratio, respectively. Daily mean consumption of liquid was 1,526.4 mL/d for males and 1,151.5 mL/d for females, and these intakes were more than the KDRI (1,300 mL/d for males and 1,100 mL/d for females). However, their sources of liquid consumption were not desirable because alcohol, soda, juice of fruit or vegetable and beverage mixed with fruit juice and/or vegetable juice were major sources of liquid as well as drinking water. These findings show that university students have poor dietary behaviors including frequent skipping of breakfast, irregularity of meals, inadequate intakes of nutrients and undesirable pattersirablliquid consumption including high portion of alcohol and soda as alliquid source, and these trends were stronger for males than for females. Therefore, we should endeavor to correct their meal problems id ated to dietary behaviors, nutrient intakes and liquid consumptions through nutrition education.

• Journal of Labour Economics
• /
• v.33 no.2
• /
• pp.1-26
• /
• 2010

Introducing a concept of 'the Effect of My Mom's Friend's Son'(MMFS Effect) into the conventional job search theory to develop it further, we try to estimate its effects on the hazard rate of youth pre-employment duration with some proxy variables such as his/her parents' schooling, monthly temporary/daily workers ratio, monthly average wage differentials between the workers of large and small firms. The results confirm us the fact that so called 'MMFS Effect' has been strengthened gradually up to recently. Their policy implications are as followings. Firstly, from the standpoint of shortening job searching period of youth and raising the hazard rate of their unemployment, the trend that the differentials of wages and quality of jobs in the labor market are expanding continuously is not desirable at all. Secondly, the problems of youth unemployment cannot be solved easily only by providing correct and relevant informations about the labor markets simply.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.4
• /
• pp.399-406
• /
• 2000

With the increase of industrialization, leisures, sports activities and traffic, the risk of trauma has increased markedly. Midfacial bones are relatively common sites of trauma, and are difficult sites of correct reduction and reconstruction, because midface is composed of mostly thin cortical bone surrounding cavities filled with either air or fat with discrete areas of bony condensation. A clinical study on 208 patients with midfacial bone fracture who visited Sanggye Paik Hospital during 5 years($1990{\sim}1995$) was done by analyzing sex, age, cause, fracture site, treatment method, complication and involvement of other body part, etc. The results obtained were as follows : 1. The occurrence was more frequent in male than in female with ratio of 2.7 : 1 and most frequently in twenties. 2. Traffic accident was the most common cause of midface fractures. 3. Zygoma was the most frequently occurred site(50%) of midface fractures. 4. Simple fracture(75%) was more frequently occurred than compound fracture(25%). 5. As treatment method, open reduction(76.4%) was used more frequently than closed reduction(23.6%) 6. Generally, operations are done in 5 days after admission(59.1%), and intermaxillary fixation was done in 78.4% of cases. 7. Teeth and alveolar bone damages were occurred in 32.2% of cases. 8. Other injuries that were related to midface fracture occurred in 63.3% of cases. 9. Post-operative complications occurred in 9% of cases.

• Korean Journal of Agricultural Science
• /
• v.46 no.4
• /
• pp.1007-1018
• /
• 2019

In the present study, according to morphological observations followed by recent circumscriptions, we have classified the Korean taxa of the family Linderniaceae into Scrophulariaceae sensu lato has been considered in several works, though the taxa have remained undefined because identification work was mostly done according to vegetative morphological features, such as the leaf shape, leaf margins, and leaf venation. The taxa of Linderniaceae are mostly considered to be weeds and, for correct identification, it is necessary to clarify their taxonomic characteristics. Morphological studies were carried out using samples collected in the field. Micro-morphological observations of the vegetative and floral parts were also performed using light microscopy (LM) and scanning electron microscopy (SEM). We concluded that important characteristics are reproductive morphologies viz. calyx, stamen structure, capsule shape, calyx ratio with capsule, inflorescence morphology, and seed morphology. As a result, we formulated taxa descriptions and provided a key of the genera of Linderniaceae in Korea. Lindernia crustacea (L.) F. Muell. is transferred to Torenia crustacea (L.) Cham. & Schltdl. Lindernia micrantha D. Don and L. angustifolia (Benth.) Wettstein are a synonym of Vandellia micrantha (D. Don) Eb. Fisch., Schäferh. & Kai Müll. Lindernia attenuata Muhl. and L. dubia var. major (Pursh) Pennell are a synonym of Lindernia dubia (L.). Lindernia verbenifolia (Colsm.) Pennell is a synonym of Bonnaya antipoda Druce. Our study reports the presence of four genera: Bonnaya, Lindernia, Torenia, and Vandellia, comprising six taxa under the family Linderniaceae in Korea.

• Journal of the Korea Society of Computer and Information
• /
• v.4 no.2
• /
• pp.1-7
• /
• 1999

World-Wide Web(WWW) is a protocol for changing information exchanges which is central to text documents in the existing network to make a multimedia data exchanges. It is possible for a beginner to search and access data which he wants to find as data were stored in the form of hypertext. The easiness for searching and accessing the multimedia data in WWW makes a important role for obscene materials to be toward generalization and multimedia and occurs social problems for them to be commercialized, while other researchers have actively studied the way to block effectively the site providing obscene materials for solving such problems. This paper presents and implements the blocking method for the sites having obscene material as it effectively search them. The proposed model was based on Link-Based information retrieval method and proved that it accomplished more efficient retrieval of relevant documents than probabilistic model when compared the one with the other which is known to generate the most correct results. The improvements in the average recall and precision ratio were shown as 12% and 8% respectively. Especially, the retrieval capability of relevant documents which include non-text data and have a few links increased highly.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2008.11a
• /
• pp.125-130
• /
• 2008

The new apartments has been rapidly built through the outskirts of Cheong-ju city since the latter half of 1980's. So, the population decreased in Seong-an dong and Jung-ang dong which are located in traditional urban area of Cheong-ju. Also, residential areas became obsolete and residential buildings happened to be vacant and empty. For urban rehabilitation, the city authorities will construct the high-rise complex housings with stores in the traditional urban area. We have doubts about whether the rapid change of new housing construction is right or not. Therefore, It is necessary to give a correct diagnosis of the present state from urban atrophy, keeping this area sustainable with traditionality and locality. This study is to examine and analysis in detail distribution patterns and habitable floor area by house types in Seong-an dong and Jung-ang dong which are located in traditional urban area of Cheong-ju. The result are as follows; the residential buildings as the 2,680 houses(including detached and apartment houses) and the 804 shop houses are distributed with 3,484(67%) of the whole 5,183 buildings and form 28percent of the whole floor areas. A distribution and area ratio of houses to shop houses is irrespectively about 76 : 24percent. The average floor area is represented with $66m^2$/household and $28.5m^2$/person. It shows that a hollowing out of urban area has caused the surplus of residential buildings and floor areas.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1044-1053
• /
• 2010

Transmitting correct train control information is important in a train control system which demands safety. The train control information includes the maximum speed of trains, position of preceding trains, incline of tracks and curve sections etc. A radio frequency-communication based train control system is influenced by the noise and interference because the train control information is transmitted by wireless between a on-board system and wayside system. The radio frequency-communication based train control system is a mobile communication system due to moving trains. The inter symbol interference(ISI) occurs by the multipath fading in the mobile ommunication system. As signal-to-noise ratio(SNR) is decreased by the ISI, the train control information is not received correctly. In case of tunnel section, numerous reflected waves exist. Therefore, the power density of receiver is decreased by difference among the received times, magnitudes, phases through the multipath. So, the train suddenly is stopped by the fail-safe operation in the train control system on account of decreasing the power density of receiver. In this paper, a line of sight model-(Additive White Gaussian noise(AWGN) channel), rayleigh and rician fading model are presented. Probability density functions which are related to the SNR are derived from the models. The fading phenomenon severely occurs as a result of analyzing the probability density functions. So, the space diversity method is used in order to reduce the fading effect and it is demonstrated by using Matlab program.