• Korean Journal of Agricultural Science
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• v.15 no.1
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• pp.82-94
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• 1988

This study was performed to obtain the basic data which can be applied to use of foaming mortars. The results obtained were summarized as follows ; 1. The lowest water-cement ratios were shown at the mixing ratio of 1 : 1. But, it was gradually increased in poorer mixing ratio and decreased in more addition of foaming agent. The water-cement ratios were decreased up to 1.6-53.1% by mix-foaming type and 4.4-24.1% by pre-foamed type than cement mortar. 2. The highest bulk densities were shown at the mixing ratio of 1 : 1. But, it was gradually decreased in poorer mixing ratio and more addition of foaming agent. The decreasing rates of bulk densities were increased in richer mixing ratio and more addition of foaming agent. 3. The bulk densities were decreased up to 38.8-55.9% by mix-foaming type and 9.7-23.6% by pre-foamed type than cement mortar. 4. The lowest absorption rates were shown at the mixing ratio of 1 : 1. But, it was gradually increased in poorer mixing ratio and more addition of foaming agent. The increasing rates of absorption rates were increased in richer mixing ratio and more addition of foaming agent. 5. Absorption rates when immersed in 72hours were shown up to 3.41-5.85 times greater by mix-foaming type and 1.05-1.55 times greater by pre-foamed type than those of cement mortar. it was significantly higher at the early stage of immersed time than cement mortar. 6. The highest strengths were shown at the mixing ratio of 1 : 1. But, it was gradually decreased in poorer mixing ratio and more addition of foaming agent. The decreasing rates of strengths were increased in poorer mixing ratio and more addition of foaming agent. 7. The strengths were decreased up to 77.0-92.8% by mix-foaming type and 36.7-74.4% by pre-foamed type than cement mortar. 8. The lowest air contents were shown at the mixing ratio of 1 : 1. But, it was gradually increased in poorer mixing ratio and more addition of foaming agent. The increasing rates of air contents were increased in richer mixing ratio and more addition of foaming agent. 9. Air contents were shown up to 26.0-63.8 times greater by mix-foaming type and 5.8-17.7 times greater by pre-foamed type than those of cement mortar. 10. The correlations between bulk density, absorption rate, compressive strength and air content were highly significant. The multiple regression equations of bulk density, absorption rate, compressive strength, tensile strength, bending strength and air content were computed depending on a function of mixing ratio and addition of foaming agent. They were generally highly significant.

• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.111-126
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• 2017

Recommender systems based on association rule mining significantly contribute to seller's sales by reducing consumers' time to search for products that they want. Recommendations based on the frequency of transactions such as orders can effectively screen out the products that are statistically marketable among multiple products. A product with a high possibility of sales, however, can be omitted from the recommendation if it records insufficient number of transactions at the beginning of the sale. Products missing from the associated recommendations may lose the chance of exposure to consumers, which leads to a decline in the number of transactions. In turn, diminished transactions may create a vicious circle of lost opportunity to be recommended. Thus, initial sales are likely to remain stagnant for a certain period of time. Products that are susceptible to fashion or seasonality, such as clothing, may be greatly affected. This study was aimed at expanding association rules to include into the list of recommendations those products whose initial trading frequency of transactions is low despite the possibility of high sales. The particular purpose is to predict the strength of the direct connection of two unconnected items through the properties of the paths located between them. An association between two items revealed in transactions can be interpreted as the interaction between them, which can be expressed as a link in a social network whose nodes are items. The first step calculates the centralities of the nodes in the middle of the paths that indirectly connect the two nodes without direct connection. The next step identifies the number of the paths and the shortest among them. These extracts are used as independent variables in the regression analysis to predict future connection strength between the nodes. The strength of the connection between the two nodes of the model, which is defined by the number of nodes between the two nodes, is measured after a certain period of time. The regression analysis results confirm that the number of paths between the two products, the distance of the shortest path, and the number of neighboring items connected to the products are significantly related to their potential strength. This study used actual order transaction data collected for three months from February to April in 2016 from an online commerce company. To reduce the complexity of analytics as the scale of the network grows, the analysis was performed only on miscellaneous goods. Two consecutively purchased items were chosen from each customer's transactions to obtain a pair of antecedent and consequent, which secures a link needed for constituting a social network. The direction of the link was determined in the order in which the goods were purchased. Except for the last ten days of the data collection period, the social network of associated items was built for the extraction of independent variables. The model predicts the number of links to be connected in the next ten days from the explanatory variables. Of the 5,711 previously unconnected links, 611 were newly connected for the last ten days. Through experiments, the proposed model demonstrated excellent predictions. Of the 571 links that the proposed model predicts, 269 were confirmed to have been connected. This is 4.4 times more than the average of 61, which can be found without any prediction model. This study is expected to be useful regarding industries whose new products launch quickly with short life cycles, since their exposure time is critical. Also, it can be used to detect diseases that are rarely found in the early stages of medical treatment because of the low incidence of outbreaks. Since the complexity of the social networking analysis is sensitive to the number of nodes and links that make up the network, this study was conducted in a particular category of miscellaneous goods. Future research should consider that this condition may limit the opportunity to detect unexpected associations between products belonging to different categories of classification.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.53-59
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• 2013

Since 1990s, the major recycling methods for mechanical recycling of FRP(Fiber Reinforced Plastics)boats has involved shredding and grinding of the scrap FRP in a new recycled product. But still it leads to secondary problem such as air pollution, unacceptable shredding noise level and few limited applications. This study is to propose a newly advanced method which is more efficient and environment friendly waste FRP regenerating system. As extracting FRP layer and making the recycled fiber for recycled-fiber reinforced concrete(RFRC) from waste FRP, the recycling process has some merits in a sense of the recycling energy and the environmental effects. In this study, for those tasks, spectro-chemical differentiation method and coloring water-soluble dye treatment makes the roving layer more distinguishable photophysically. Also that has remarkably reduced safety hazards and energy. Using the mechanical properties of polymers and composite, FRP with the orthotropic and laminated plastic structure has been easily separated in the new extracting system. Also the new method has introduced five kind of separating manuals for the some different compositions of FRP boats. The roving fiber of laminated glass-fiber layer is as good as the polyvinyl fiber which is cost-high commercial fiber to increasing strength of concrete products. The early study has shown the effectiveness of laminated glass-fiber layer which also is chemical-resistant due to the resin coating. These results imply that more efficient and environment friendly recycled glass fiber can be better applied to the fiber reinforced concrete(FRC) substitute and this study also has shown wide concrete applications with RFRC from the waste FRP boat.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.659-666
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• 2012

To secure the thermal crack resistance of mass concrete, researches and the field applications of low heat portland cement (LPC), ternary blended cement (TBC) which is produced by blending ordinary portland cement with blast furnace slag and fly ash, and early strength low heat blended cement (EBC) increased in recent years. Although the model for adiabatic temperature rise is necessary for estimating the risk of thermal cracking of concrete structures, sufficient data have not been accumulated for these mixtures. In addition, the differences in adiabatic test results have been reported for the volume of test specimens. Therefore, the present study evaluated the characteristics of adiabatic temperature rise based on the type of binder and the volume of the adiabatic test specimen. Test results indicated that the maximum temperature rise ($Q_{\infty}$) and the reaction factor (r) of TBC were the lowest. Test results also showed that $Q_{\infty}$ and r changed with respect to the volume of test specimen. $Q_{\infty}$ and r obtained from 6l equipment were lower than those of 50l equipment. Therefore, corrections with respect to this phenomenon was confirmed and the corrections factors are presented.

• The Journal of the Acoustical Society of Korea
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• v.31 no.3
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• pp.115-128
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• 2012

This paper investigates the effects of diffuser on the acoustical parameters in music hall with consideration of the result of scattering coefficient measurement. A scale model hall of 600 seats with orchestra shell was used for experiments. The materials of 1:50 scale model was chosen through absorption coefficient measurement based on ISO 354. The model was matched to the computer simulation model in terms of reverberation time. In order to evaluate the effect of diffuser location, the measurements were accomplished with and without diffusers according to 7 configurations by diffuser-installed region; sidewall, balcony front, ceiling and so on. The following acoustical parameters were extracted from each measurement case; Reverberation time (RT), Early decay time (EDT), Clarity (C80), Center time (Ts), Sound strength (G) and Temporal diffusion (TD) from the auto-correlation function (ACF) of impulse responses. As a result, the absorption power and diffusion power were increased with number of diffusers. Accordingly RT, EDT and G were decreased by diffuser and the redirection of reflections was occurred briskly. Averaged TD was 6.05 to 6.30 by measurement cases. RT was found to be the most related factor to diffusion power (R = 0.94). The correlation between TD and EDT was high (R = 0.73). In addition, the effects of diffuser-installed location were discussed in terms of acoustical parameter variation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.334-346
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• 2017

The purpose of this study was to identify the inner characteristics of nurses that contributed to their overcoming work-related stress and continuing to work in hospitals. We sought to identify strategies nurses used to reduce early turn-over intention and promote job retention. Twelve nurses with at least five years of work experience were recruited from two tertiary-level hospitals and three general hospitals in Seoul and Gyeonggi for focus group interviews. Data were collected from January 27 to April 20, 2016. Qualitative data were analyzed using content analysis. Based on the results, the inner characteristics and strengths of these nurses were classified into four categories and 13 sub-categories. The four categories wereas follows: "efforts to overcome self," "positive attitude," "effective communication and support from surroundings," and "aim to grow as a nursing professional." The results of this study indicate that the strength of nurses should be enhanced to facilitate a continued desire to work. Training for self-reflective practice is recommended to improve resilience, positive attitudes, and communication skills, as well as to establish job identity.

• Strategy21
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• s.34
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• pp.93-127
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• 2014

During the four years following the sinking of the Cheonan frigate in 2010, the South Korean public opinion has seen changes in four basic ways. First, public polls with respect to the cause of the sinking show that 70% of the people consider North Korea as the culprit, while 20% maintain that it was not an act carried out by North Korea. Second, the opinions relative to the cause of the incident seem to vary according to age difference, generational difference, and educational difference. From 2011, people in their 20s showed 10% increase in regarding North Korea as the responsible party. People in their 30s and 40s still have a tendency not to believe the result of the investigation carried out by the combined military and civilian group. Third, the most prominent issue that arose aftermath of the Cheonan incident is the fact that political inclination and policy preference are influencing the scientific determination of the cause. In other words, scientific and logical approach is lacking in the process of determining the factual basis for the cause. This process is compromised by the inability of the parties concerned in sorting out what is objective and what is personal opinion. This confused state of affairs makes it difficult to carry on a healthy, productive debate. Fourth, rumors, propaganda, and disinformation generated by pro-North Korea Labor Party groups in the internet and SNS are causing considerable impact in forming the public opinion. Proposed Strategy 1. The administration can ascertain public trust by accurately determining the nature of the provocation based on accurate information in the early stages of the incident. 2. Education in scientific, logical, rational methodologyis needed at home, school, and workplace in order toenhance the people's ability to seek factual truths. 3. In secondary education, the values of freedom, human rights, democracy, and market economy must be reinforced. 4. It is necessary for the educational system to teach the facts of North Korea just as they are. 5. Fundamental strength of free democratic system must be reinforced. The conservative, mainstream powers must recognize the importance of self-sacrifice and societal duties. The progressive political parties must sever themselves from those groups that take instructions from North Korea's Labor Party. The progressives must pursue values that are based on fundamental human rights for all. 6. Korean unification led by South Korea is the genuine means to achieve peace in a nuclear-free Korean peninsula. The administration must recognize that this unification initiative is the beginning of the common peace and prosperity in the Far East Asia, and must actively pursue international cooperation in this regard.

• Food Science and Preservation
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• v.12 no.6
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• pp.578-582
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• 2005

This study was carried out to analyze the quality change of mackerel treated with extracts of Diospyros kaki, Teucerium veronicoides and Z schinifolium during storage to develope the preparation methods and high quality of salted mackerel. It was analyzed to change on th quality of salted mackerel treated with hero extracts. The Hunters color values of salted mackerel was not changed during strange. L, a, and b value of Mackerel treated with hero extracts was lower changed than those of control (mackerel not treated hero extracts). Adhesion of mackerel was higher at $4^{\circ}C$ during storage than those at $25^{\circ}C$, and was higher in the hero extract treated group at early storage than those of control group. Viscosity was showed low changed in all group during storage. Strength of mackerel was decreased during storage. Hardness was salted mackerel treated with hero extracts was higher than those of control group. Mackerel treated with Z schinifolium extracts was the highest scores in sensory evaluation.

• Science of Emotion and Sensibility
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• v.13 no.3
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• pp.449-458
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• 2010

As occasion demands to obtain efficient information from many documents and reviews on the Internet in many kinds of fields, automatic classification of opinion or thought is required. These automatic classification is called sentiment classification, which can be divided into three steps, such as subjective expression classification to extract subjective sentences from documents, sentiment classification to classify whether the polarity of documents is positive or negative, and strength classification to classify whether the documents have weak polarity or strong polarity. The latest studies in Opinion Mining have used N-gram words, lexical phrase pattern, and syntactic phrase pattern, etc. They have not used single word as feature for classification. Especially, patterns have been used frequently as feature because they are more flexible than N-gram words and are also more deterministic than single word. Theses studies are mainly concerned with English, other studies using patterns for Korean are still at an early stage. Although Korean has a slight difference in the meaning between predicates by the change of endings, which is 'Eomi' in Korean, of declinable words, the earlier studies about Korean opinion classification removed endings from predicates only to extract stems. Finally, this study introduces the earlier studies and methods using pattern for English, uses extracted sentimental patterns from Korean documents, and classifies polarities of these documents. In this paper, it also analyses the influence of the change of endings on performances of opinion classification.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.172-176
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• 2008

Purpose: The proper surgical methods for treating acromioclavicular joint dislocation is still controversial. New methods should provide better early motion with sufficient strength. Materials and Methods: We performed arthroscopic stabilization using TightRope$^{(R)}$ (Arthrex, Inc, Naples, FL) in 10 cases of acromioclavicular joint dislocation between April, 2007, and December, 2007, and followup for a minimum of 10 months. We performed radiologic evaluation by comparing the clavicle anteroposterior radiograph with the contralateral one. Clinical evaluation was made for pain, function, and range of joint motion by Imatani's methods. Results: In clinical evaluation, 6 cases were excellent, 3 cases were good, and 1 case was poor. In radiologic evaluation, 9 cases were excellent and 1 case was poor. Redislocation occurred in 1 case. Conclusion: During short-term followup, 9 of 10 patients who underwent arthroscopic stabilization using TightRope$^{(R)}$ had excellent results in Imatini tests and radiologic evaluation, except 1 patient with redislocation.