• Korean Journal of Environmental Agriculture
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• v.28 no.2
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• pp.125-130
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• 2009

The aim of this study was to investigate whether differences in the distribution of soil invertebrates among different vegetation types (forest, reservoir, and crop land types) in rural area. A total of 18 orders and 137 species were collected by pitfall traps. Species numbers were the lowest (33 species) at the Chamaecyparis obtusa plantation (St. 6). On the forest sites, the individual number of Hymenoptera was the most abundant, and Acari and Coleoptera was the relatively more abundant than the other sites. On the reservoir sites (Salix chaenomeloides community), the individual number of Collembola was the most abundant, and Diptera was the relatively more abundant than the other sites. On the crop land sites, the individual numbers of Collembola, Hymenoptera, and Araneae were the relatively more abundant than the other orders. The density of Araneae was higher in the reservoir and crop land sites than in the forest sites. From a point of view of biodiversity, although the diversity index(H') was the highest in the mixed broad-leaved forest type (St. 2) with Quercus serrata and Q. acutissima, and the lowest in the upland levee of crop land(St. 11), there was no significant difference among the habitat or vegetation types. According to the community analysis, the soil invertebrates could be divided into 4 groups, the mixed broad-leaved forest type (A group), the plantation or pure forest type (B group), the reservoir type (C group), and the crop land type (D group).

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.595-603
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• 2005

Incomplete removal of bacteria contaminated dentin or enamel associated with caries is a potential problem in restorative dentistry Secondary or residual caries, pulpal inflammation and hypersensitivity may result from bacteria left after the initial preparation, especially if an adequate seal against microleakage is not obtained. A possible solution to eliminate residual bacteria left in a cavity preparation would be to treat the cavity with cavity disinfectant wash. But a potential problem with using a cavity disinfectant with dentin bonding agents could be their interference with the ability of the resin to bond to the tooth micromechanically. The purpose of this study was to evaluate the effect of 2% chlorhexidine containing cavity disinfectant ($Consepsis^{(R)}$) on shear bond strength and microleakage of dentin bonding agents, $Adper ^{TM}$ $Scotchbond^{TM}$ Multi-Purpose, $Adper^{TM}$ Single Bond and $Adper^{TM}\;Prompt^{TM}\; L-Pop^{TM}$ Sixty and sixty sound human third molar teeth, respectively, were used for shear bond strength and microleakage test. For experimental group, cavity disinfectant was applied before dentin bonding agents, and was not applied for the control group. The result from the this study can be summarized as follows ; 1. Use of 2% chlorhexidine containing cavity disinfectant($Consepsis^{(R)}$) does not significantly affect the shear bond strength of dentin bonding agents. 2. Use of 2% chlorhexidine containing cavity disinfectant($Consepsis^{(R)}$) does not significantly affect the microleakage of dentin bonding agents.

• Journal of Intelligence and Information Systems
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• v.16 no.4
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• pp.67-84
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• 2010

In terms of business, forecasting is a work of what is expected to happen in the future to make managerial decisions and plans. Therefore, the accurate forecasting is very important for major managerial decision making and is the basis for making various strategies of business. But it is very difficult to make an unbiased and consistent estimate because of uncertainty and complexity in the future business environment. That is why we should use scientific forecasting model to support business decision making, and make an effort to minimize the model's forecasting error which is difference between observation and estimator. Nevertheless, minimizing the error is not an easy task. Case-based reasoning is a problem solving method that utilizes the past similar case to solve the current problem. To build the successful case-based reasoning models, retrieving the case not only the most similar case but also the most relevant case is very important. To retrieve the similar and relevant case from past cases, the measurement of similarities between cases is an important key factor. Especially, if the cases contain symbolic data, it is more difficult to measure the distances. The purpose of this study is to improve the forecasting accuracy of case-based reasoning approach using fuzzy relation and composition. Especially, two methods are adopted to measure the similarity between cases containing symbolic data. One is to deduct the similarity matrix following binary logic(the judgment of sameness between two symbolic data), the other is to deduct the similarity matrix following fuzzy relation and composition. This study is conducted in the following order; data gathering and preprocessing, model building and analysis, validation analysis, conclusion. First, in the progress of data gathering and preprocessing we collect data set including categorical dependent variables. Also, the data set gathered is cross-section data and independent variables of the data set include several qualitative variables expressed symbolic data. The research data consists of many financial ratios and the corresponding bond ratings of Korean companies. The ratings we employ in this study cover all bonds rated by one of the bond rating agencies in Korea. Our total sample includes 1,816 companies whose commercial papers have been rated in the period 1997~2000. Credit grades are defined as outputs and classified into 5 rating categories(A1, A2, A3, B, C) according to credit levels. Second, in the progress of model building and analysis we deduct the similarity matrix following binary logic and fuzzy composition to measure the similarity between cases containing symbolic data. In this process, the used types of fuzzy composition are max-min, max-product, max-average. And then, the analysis is carried out by case-based reasoning approach with the deducted similarity matrix. Third, in the progress of validation analysis we verify the validation of model through McNemar test based on hit ratio. Finally, we draw a conclusion from the study. As a result, the similarity measuring method using fuzzy relation and composition shows good forecasting performance compared to the similarity measuring method using binary logic for similarity measurement between two symbolic data. But the results of the analysis are not statistically significant in forecasting performance among the types of fuzzy composition. The contributions of this study are as follows. We propose another methodology that fuzzy relation and fuzzy composition could be applied for the similarity measurement between two symbolic data. That is the most important factor to build case-based reasoning model.

• Clean Technology
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• v.24 no.4
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• pp.371-379
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• 2018

The objective of this study is to develop a platinum/hexaaluminate pellet catalyst for the decomposition of eco-friendly liquid propellant. Pellet catalysts using hexaaluminate prepared by ultrasonic spray pyrolysis as a support and platinum as an active metal were prepared by two methods. In the case of the pellet catalyst formed by loading the platinum precursor onto the hexaaluminate powder and then adding the binder (M1 method catalyst), the mesopores were well developed in the catalyst after calcination at $550^{\circ}C$. However, when this catalyst was calcined at $1,200^{\circ}C$, the mesopores almost collapsed and only a few macropores existed. On the other hand, in the case of a catalyst in which platinum was supported on pellets after the pellet was produced by extrusion of hexaaluminate (M2 method catalyst), the surface area and the mesopores were well maintained even after calcination at $1,200^{\circ}C$. Also, the catalyst prepared by the M2 method showed better heat resistance in terms of platinum dispersion. The effects of preparation method and calcination temperature of Pt/hexaaluminate pellet catalysts on the decomposition of liquid propellant composed mainly of ammonium dinitramide (ADN) or hydroxyl ammonium nitrate (HAN) were investigated. It was confirmed that the decomposition onset temperature during the decomposition of ADN- or HAN- based liquid propellant could be reduced significantly by using Pt/hexaaluminate pellet catalysts. Especially, in the case of the catalyst prepared by the M2 method, the decomposition onset temperature did not show a large change even when the calcination temperature was raised at $1,200^{\circ}C$. Therefore, it was confirmed that Pt/ hexaaluminate pellet catalyst prepared by M2 method has heat resistance and potential as a catalyst for the decomposition of the eco-friendly liquid propellants.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.4-21
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• 2021

A stone mold from the Sabi period of Baekje was excavated at the western tombs in Neungsan-ri, Buyeo where there was a recent excavation survey (2016). It was believed and reported that such stone molds were used for copper needles during the early Iron Age; however, a close re-examination of the form revealed that they were used for bifid ornamental hairpins. Given its casting form, the stone mold of Neungsan-ri is estimated to have been used to make bifid ornamental hairpins in a ∩ shape, narrowing down toward the tip. It is considered an artifact of the Goryeo dynasty. The stone used to make the bifid ornamental hairpin mold of Neungsan-ri was chlorite-schist, the principal minerals of which include chlorite, amphibole, and talc. Similar rocks are in nearby Buyeo (Oesan-myeon), Cheongyang, Gongju, and Yesan. They are mainly found between Jiseon-ri, Oesan-myeon, Buyeo, Sucheol-ri, Yesane-up, and Yesan. Nearly 70 bifid ornamental hairpins from the Goryeo dynasty were excavated at Neungsan-ri, Buyeo and the surrounding areas. Among them, the bronze ones excavated from the tombs of Songguk-ri, Buyeo are estimated to have been made using this mold as they closely resemble the Neungsan-ri mold. Stone was likely the preferred material for molds to make bronze artifacts as it was easy to sink a die. Regarding the bifid ornamental hairpin cast excavated in Neungsan-ri, they obtained stones in nearby areas 20~50km from their location, made bronze artifacts, and distributed them to nearby sites during the Goryeo dynasty. These artifacts suggest that the casting technology of using a stone mold was still employed then.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.136-149
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• 2022

In this study, the performance of a nonlinear mixed-effects (NLME) model used to estimate the stem taper of Pinus densiflora in Gangwon Province was compared with that of a nonlinear fixed-effects (NLFE) model using several performance measures. For the diameters of whole tree stems, the NLME model improved on the performance of the NLFE model by 26.4%, 42.9%, 43.1%, and 0.9% in terms of BIAS, MAB, RMSE, and FI, respectively. For the cross-section areas of whole tree stems, the NLME model improved on the performance of the NLFE model by 67.7%, 44.7%, 45.8%, and 1.0% in terms of BIAS, MAB, RMSE, and FI, respectively. Based on the analysis of 12 relative height classes of tree stems, stem taper estimation performance was also reasonably improved by the NLME model, which showed better MAB, RMSE, and FI at every relative height class compared with those of the NLFE model. In some classes, the NLFE model had better BIAS than the NLME model (stem diameter: 0.05, 0.2, 0.3, and 0.8; stem cross-section area: 0.05, 0.3, 0.5, 0.6, and 1.0). However, the NLME model enhanced the performance of stem diameter and cross-section area estimations at the lowest stem part (0.2 m from the ground). Improvements for stem diameter in terms of BIAS, MAB, RMSE, and FI were 84.2%, 69.8%, 68.7%, and 3.1%, respectively. For stem cross-section areas, the improvements in BIAS, MAB, RMSE, and FI were 98.5%, 70.1%, 68.7%, and 3.1%, respectively. The cross-section area at 0.2 m from the ground occupied 22.7% of total cross-section area. Improvements in estimation of cross-section area at the lowest stem part indicate that stem volume estimation performance could also be enhanced. Although NLME models are more difficult to fit than NLFE models, the use of NLME models as a standard method for the estimating the parameters of stem taper equations should be considered.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.35-43
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• 2023

The purpose of this study is to research digital twin policies for the use of administrative services. The study was conducted through a mobile survey of 1,000 participants, and the results are as follows. First, in order to utilize digital twin technology, it is necessary to first identify appropriate services that can be applied from the perspective of Gyeonggi Province. Efforts to identify digital twin services that are suitable for Gyeonggi Province's field work should be prioritized, and this should lead to increased efficiency in the work. Second, Gyeonggi Province's digital twin administrative services should prevent duplication with central government projects and establish a model that can be connected and utilized. It should be driven around current issues in Gyeonggi Province and the demands of citizens for administrative services. Third, to develop Gyeonggi Province's digital twin administrative services, a standard model development plan through participation in pilot projects should be considered. Gyeonggi Province should lead the project as the main agency and promote it through a collaborative project agreement. It is suggested that a support system for the overall project be established through the Gyeonggi Province Digital Twin Advisory Committee. Fourth, relevant regulations and systems for the construction, operation, and management of dedicated departments and administrative services should be established. To achieve the realization of digital twins in Gyeonggi Province, a dedicated organization that can perform various roles in project promotion and operation, as well as legal and institutional improvements, is necessary. To designate a dedicated organization, it is necessary to consider expanding and reorganizing existing departments and evaluating the operation of newly established departments. The limitation of this study is that it only surveyed participants from Gyeonggi Province, and it is recommended that future research be conducted nationwide. The expected effect of this study is that it can serve as a foundational resource for applying digital twin services to public work.

• The Journal of Korean Society for School & Community Health Education
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• v.25 no.2
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• pp.27-44
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• 2024

Objectives: This study aimed to provide foundational data for preventing adolescents smoking by analyzing the relationship between adolescents' lifestyles and smoking experiences and identifying influencing factors. Methods: Secondary data analysis was conducted using the 17th (2021) Youth Health Behavior Survey data, encompassing 54,848 students from 796 schools. Variables included general characteristics, smoking status, lifestyle habits, physical activity, sleep patterns, and stress perception. Frequency analysis was used to examine general characteristics, while further analysis employed frequency analysis and the Pearson Chi-square test to compare lifestyle differences based on smoking presence. Multinomial logistic regression analysis was employed to determine factors influencing smoking experience, with IBM SPSS Statistics 28 used for all analyses at a significance level of p<.05. Results: Analysis revealed with general characteristics that the group with smoking experience exhibited a higher proportion of male students (67.4%) compared to the non-smoking group (50.1%) (p<.001). Analysis revealed that the smoking group was more likely to skip breakfast (27.7%), not consume fruit (17.8%), and consume fast food more than three times daily (0.9%). Furthermore, a higher percentage of smokers engaged in 60 minutes or more of breathless physical activity (8.4%) seven times a week, reported insufficient fatigue recovery through sleep (21.6%), and experienced very severe normal stress (17.2%) (p<.001). Analysis of the relationship between lifestyle and smoking indicated increased likelihood of smoking with zero breakfast consumption (OR=1.759, p<.001) and increased fruit consumption (OR=1.921, p<.001), while zero fast food consumption decreased smoking likelihood (OR=0.206, p<.001). Adequate sleep-related fatigue recovery reduced smoking likelihood (OR=0.458, p<.001), whereas increased stress elevated it (OR=1.260, p<.05). Conclusion: Adolescents' lifestyle habits significantly correlated with their smoking experiences, highlighting the necessity of considering lifestyle factors in smoking prevention strategies. This study provides crucial insights for promoting healthy lifestyle changes to prevent smoking among youth.

• The Southeast Asian review
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• v.27 no.2
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• pp.37-76
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• 2017

$Nguy{\tilde{\hat{e}}}n$ Cư Trinh has two faces in the history of territorial expansion of Vietnam into the Mekong delta. One is his heroic contribution to the $Nguy{\tilde{\hat{e}}}n$ family gaining control over the large part of the Mekong delta. The other is his role to make the eyes of readers of Vietnamese history be fixed only to the present territory of Vietnam. To the readers, $Nguy{\tilde{\hat{e}}}n$ Cư Trinh's achievement of territorial expansion was the final stage of the nam $ti{\acute{\hat{e}}n$ of Vietnam. In fact, however, his achievement was partial. This study pays attention to the King $V{\tilde{o}}$ instead of $Nguy{\tilde{\hat{e}}}n$ Cư Trinh in the history of the territorial expansion in the Mekong delta. King's goal was more ambitious. And the ambition was propelled by his dream to build a new world, and its order, in which his new capital, $Ph{\acute{u}}$ $Xu{\hat{a}}n$ was to be the center with his status as an emperor. To improve my assertion, three elements were examined in this article. First is the nature of $V{\tilde{o}}$ Vương's new kingship. Second is the preparation and the background of the military operation in the Mekong Delta. The nature of the new territory is the third element of the discussion. In 1744, six years after this ascending to the throne, $V{\tilde{o}}$ Vương declared he was a king. Author points out this event as the departure of the southern kingdom from the traditional dynasties based on the Red River delta. Besides, the government system, northern custom and way of dressings were abandoned and new southern modes were adopted. $V{\tilde{o}}$ Vương had enough tributary kingdoms such as Cambodia, Champa, Thủy $X{\tilde{a}}$, Hoả $X{\tilde{a}}$, Vạn Tượng, and Nam Chưởng. Compared with the $L{\hat{e}}$ empire, the number of the tributary kingdoms was higher and the number was equivalent to that of the Đại Nam empire of the 19th century. In reality, author claims, the King $V{\tilde{o}}^{\prime}s$ real intention was to become an emperor. Though he failed in using the title of emperor, he distinguished himself by claiming himself as the Heaven King, $Thi{\hat{e}}n$ Vương. Cambodian king's attack on the thousands of Cham ethnics in Cambodian territory was an enough reason to the King $V{\tilde{o}}^{\prime}s$ military intervention. He considered these Cham men and women as his amicable subjects, and he saw them a branch of the Cham communities in his realm. He declared war against Cambodia in 1750. At the same time he sent a lengthy letter to the Siamese king claiming that the Cambodia was his exclusive tributary kingdom. Before he launched a fatal strike on the Mekong delta which had been the southern part of Cambodia, $V{\tilde{o}}$ Vương renovated his capital $Ph{\acute{u}}$ $Xu{\hat{a}}n$ to the level of the new center of power equivalent to that of empire for his sake. Inflation, famine, economic distortion were also the features of this time. But this study pays attention more to the active policy of the King $V{\tilde{o}}$ as an empire builder than to the economic situation that has been told as the main reason for King $V{\tilde{o}}^{\prime}s$ annexation of the large part of the Mekong delta. From the year of 1754, by the initiative of $Nguy{\tilde{\hat{e}}}n$ Cư Trinh, almost whole region of the Mekong delta within the current border line was incorporated into the territory of $V{\tilde{o}}$ Vương within three years, though the intention of the king was to extend his land to the right side of the Mekong Basin beyond the current border such as Kampong Cham, Prey Vieng, and Svai Rieng. The main reason was $V{\tilde{o}}$ Vương's need to expand his territory to be matched with that of his potential empire with the large number of the tributary kingdoms. King $V{\tilde{o}}^{\prime}s$ strategy was the variation of 'silkworm nibbling' and 'to strike barbarians by barbarians.' He ate the land of Lower Cambodia, the region of the Mekong delta step by step as silkworm nibbles mulberry leave(general meaning of $t{\acute{a}}m$ thực), but his final goal was to eat all(another meaning of $t{\acute{a}}m$ thực) the part of the Mekong delta including the three provinces of Cambodia mentioned above. He used Cham to strike Cambodian in the process of getting land from Long An area to $Ch{\hat{a}}u$ Đốc. This is a faithful application of the Dĩ Man $C{\hat{o}}ng$ Man (to strike barbarians by barbarians). In addition he used Chinese refugees led by the Mạc family or their quasi kingdom to gain land in the region of $H{\grave{a}}$ $Ti{\hat{e}}n$ and its environs from the hand of Cambodian king. This is another application of Dĩ Man $C{\hat{o}}ng$ Man. In sum, author claims a new way of looking at the origin of the imperial world order which emerged during the first half of the 19th century. It was not the result of the long history of Đại Việt empires based on the Red River delta, but the succession of the King $V{\tilde{o}}^{\prime}s$ new world based on $Ph{\acute{u}}$ $Xu{\hat{a}}n$. The same ways of Dĩ Man $C{\hat{o}}ng$ Man and $T{\acute{a}}m$ Thực Chi $K{\acute{\hat{e}}}$ were still used by $V{\tilde{o}}^{\prime}s$ descendents. His grandson Gia Long used man such as Thai, Khmer, Lao, Chinese, and European to win another man the '$T{\hat{a}}y$ Sơn bandits' that included many of Chinese pirates, Cham, and other mountain peoples. His great grand son Minh Mạng constructed a splendid empire. At the same time, however, Minh Mạng kept expanding the size of his empire by eating all the part of Cambodia and Cham territories.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.21-25
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• 2010

Purpose: For better PET imaging with accuracy the transmission scanning is inevitably required for attenuation correction. The attenuation is affected by condition of acquisition and patient position, consequently quantitative accuracy may be decreased in emission scan imaging. In this paper, the present study aims at providing the measurement for attenuation varying with the positions of the patient's arm in whole body PET/CT, further performing the comparative analysis over its SUV changes. Materials and Methods: NEMA 1994 PET phantom was filled with $^{18}F$-FDG and the concentration ratio of insert cylinder and background water fit to 4:1. Phantom images were acquired through emission scanning for 4min after conducting transmission scanning by using CT. In an attempt to acquire image at the state that the arm of the patient was positioned at the lower of ahead, image was acquired in away that two pieces of Teflon inserts were used additionally by fixing phantoms at both sides of phantom. The acquired imaged at a were reconstructed by applying the iterative reconstruction method (iteration: 2, subset: 28) as well as attenuation correction using the CT, and then VOI was drawn on each image plane so as to measure CT number and SUV and comparatively analyze axial uniformity (A.U=Standard deviation/Average SUV) of PET images. Results: It was found from the above phantom test that, when comparing two cases of whether Teflon insert was fixed or removed, the CT number of cylinder increased from -5.76 HU to 0 HU, while SUV decreased from 24.64 to 24.29 and A.U from 0.064 to 0.052. And the CT number of background water was identified to increase from -6.14 HU to -0.43 HU, whereas SUV decreased from 6.3 to 5.6 and A.U also decreased from 0.12 to 0.10. In addition, as for the patient image, CT number was verified to increase from 53.09 HU to 58.31 HU and SUV decreased from 24.96 to 21.81 when the patient's arm was positioned over the head rather than when it was lowered. Conclusion: When arms up protocol was applied, the SUV of phantom and patient image was decreased by 1.4% and 9.2% respectively. With the present study it was concluded that in case of PET/CT scanning against the whole body of a patient the position of patient's arm was not so much significant. Especially, the scanning under the condition that the arm is raised over to the head gives rise to more probability that the patient is likely to move due to long scanning time that causes the increase of uptake of $^{18}F$-FDG of brown fat at the shoulder part together with increased pain imposing to the shoulder and discomfort to a patient. As regarding consideration all of such factors, it could be rationally drawn that PET/CT scanning could be made with the arm of the subject lowered.