• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.91-99
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• 2017

The purpose of this paper is to evaluate the flexural performance of reinforced concrete (RC) beams repaired with polymer mortar. The repaired and non-repaired 13th beams which was fabricated by considering repair position, repair depth, and curing age of polymer mortar as test variables were tested under three point loading. All specimens repaired in compressive and tensile zone did not fail due to interfacial failure between polymer mortar and concrete but failed when the strain of repaired mortar exceeded the ultimate tensile strain of polymer mortar. Maximum load of specimens repaired in compressive zone was similar to that of non-repaired specimen, reference specimen. Additionally, their ductility index was higher than that of reference specimen. On the other hand, specimens repaired in tensile zone failed very brittlely and have a lower ductility index than reference specimen. Nonlinear analysis by using OpenSees was performed to predict the behavior of RC beam repaired with polymer mortar. Two dimension frame element was used to simplify an analysis model and fiber model was applied to consider the material non-linearity. It was confirmed from the analysis results that nonlinear analysis properly predicts the behavior of specimens repaired in compressive zone and overestimates the behavior of specimens repaired in tensile zone.

• Survey Research
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• v.5 no.1
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• pp.51-78
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• 2004

This paper examines political leaders' image based on the concepts of social identity and distance. These concepts come from the two ideas: (1) Individuals create events to confirm the sentiments that they have about themselves and others in the current situation. (2) During this process structured sets of beliefs (social identity) about attributes of various entities are formed. Statistical analysis of the data from college students in Seoul offers three main findings. First, attributes clustered into four major groups-sociability, responsibility, power and activity. Sociability concerns as sense of approval or disapproval that can elaborated into closeness and intimacy. Responsibility relates to the judgement of morality, public obligation, or other standards. Power refers to social power, physical magnitude and so on. Activity indexes an entity's spontaneity, which can be elaborate into judgements of agency, speed and so on, Second, respondents evaluate negatively political leaders at the dimensions of sociability, responsibility, and activity, They are positively evaluated only at the dimension of power. Third, political leaders who are felt to be closer than others seem to have more political support nowadays.

• The korean journal of orthodontics
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• v.40 no.5
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• pp.334-341
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• 2010

Objective: The purpose of this study was to evaluate morphologic differences in the mandibular arch between Egyptian and Korean subjects. Methods: The Egyptian sample consisted of 94 mandibular casts (35 Class I, 32 Class II and 27 Class III). The Korean sample consisted of 462 mandibular casts (114 Class I, 119 Class II, and 135 Class III). The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth. The subjects were grouped according to arch form to compare the frequency distribution of the 3 arch forms between the ethnic groups in each Angle classification. Results: Egyptians had significantly narrower intermolar and intercanine widths ($p$ < 0.001), and shallower intermolar and intercanine depths ($p$ < 0.001) than Koreans. There was an even frequency distribution of the 3 arch forms within the Egyptian group ($p$ = 0.46). However, in the Korean group, the most frequent arch form was the square arch form (46.7%), while the frequency of the tapered arch form was significantly lower (18.8%). Conclusions: These results might provide helpful information in evaluating morphologic differences between ethnic groups in selection of preformed superelastic archwires.

• Korean Security Journal
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• no.15
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• pp.107-128
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• 2008

It was started that Shiwe-goon was organized from Shilla-end to Goryeo foundation a country in powerful families existence merely royal household by stably plan means in the reign of Taejo. Generally Shiwe-goon was dutie king' personal danger of protection. Shiwe-goon was organized castle of guarding, stand by king and royal household side armed strength to going on a trip and general armed-organization was collapsed for Goryeo-end continued existence. Goryeo era of Shiwe-organization was divided central army and region army. Two-goon(Eungyang-goon, Yongho-goon) was undertaken king of Shiwe army and six-we(Chunwoo-we, Geumoh-we, Gammoon-we, Jeoawoo-we, Shinoh-we, Hongwe-we) was undertaked capital of guard and the border of defense duty. Central army of commanders was called Sangjanggoon, Daejanggoon. Sangjanggoon and Daejanggoon was discussed military officer of conference apparatus in Jungbang. Jungbang was got afterward Mooshinjungbeon happened military of statesman grasping political power with authority a main stay. Mooshinjungkwen era was appeared modernistic mean of privately guarding organization in Dobang and Naedobang. According as Shiwe-organization was charged military organization as a part of sovereign power and grasping strength of authority- maintenance for security and guarding duty. As a conclusion, national sovereign of guard was achieved not only personal life and body guard protection but also country of welfare protection in country-welfare dimension an inch of non-error. Also national sovereign of guard was considered guarding apparatus of allowance the largest duty and country-welfare direct connection with actual fact recognition in constancy effort.

• Korean Journal of Plant Resources
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• v.22 no.1
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• pp.96-101
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• 2009

Dokdo was formed since when four million six hundred thousand to two million five hundred thousand. Dokdo, Ulreung Island and the mainland in Korea are not touch each other since the formation, therefore, Dokdo are very important island for discussion of plant evolution from plant geography point of view. Plants of Dokdo was enlisted as 60 taxa, 27 families, 52 genera, 50 species and 10 varieties. The naturalized plants of a wide sense is composed of 25 taxa, two tree species as Lonicera morrowii and Elaeagnus macrophylla, and 23 herbs. The naturalized plants were identified of 5 species as Sonchus oleraceus, Brassica juncea var. integrifolia, Rumex crispus, Chenopodium album, and Bromus unioloides. Total naturalized plants are 32 taxa, ratio of total naturalized plants per a existing species was 60 percentage. Accordingly Vegetational environment of Dokdo was interpreted very incomplete state as well as severe ecological disturb by invade species. Preparation of a regulating plan on naturalized plants and concern of a policy decision are requested in the conservational dimension for native species in Dongdo. For the conservation of native species in Dokdo, there are prepared that a regulating plan as block of the influx and eradication etc. and a policy decision of naturalized plants are prepared for view of the conservation for native species in Dokdo.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.135-140
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• 1998

Drag reduction produced by dilute solution of water soluble ionic polymer-surfactant complex under turbulent flow in a rotating disk apparatus(RDA) was investigated in this study. Three different molecular weights of polyacrylic acid(PAA) were adopted as drag reducing additives, and distilled water was used as a solvent. Experiments were undertaken to observe the dependence of drag reduction on various factors such as polymer molecular weight, molecular expansions and flexibility, rotating speed of the disk and polymer concentration. Specific considerations were put on conformational difference between surfactant and polymer, and effect of pH on ionic polymer possessing various molecular conformation through pH. The complex of ionic polymer and surfactant(Sodium Dodecyl Sulfate) behaves like a large polyelectrolyte. Surfactant changes the polymer conformation and then increases the dimension of the polymer. The radius of gyration, hydrodynamic volume and relative viscosity of the polymer-surfactant system are observed to be greater than those of polymer itself. Such surfactant-polymer complex has enhanced drag reduction properties.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.2 s.16
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• pp.61-69
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• 2000

Until now, the extraction of information on geographic features and the compilation of maps from satellite imagery has had many limitations because of its lower resolution compared to aerial photos to the recent. However, it is expected that the availability of high resolution satellite imagery whose spatial resolution is about 1m will reduce such limitations. Currently, a compilation of national-wide digital base maps is going on to construct the National Geographic Information Systems in Korea. It will be used for many application field of the social welfare. Therefore, in this study, we suggest that satellite imagery can help it and we have experimented on the possibility of detecting and interpreting geographic data using satellite imagery of various spatial resolutions. The interpretability and detectability of 46 features in 6 categories was experimented with 6 kinds of images of different resolutions. As a subsequent procedure, we have performed the fractal analysis for a quality test of the texture information. Through the fractal analysis, we could show that texture information and probability of discrimination increases as the spatial resolution of the image increases. Based on the results of this experiment, we could suggest the possibility of the renewal and construction of the National-wide Geographic Information Systems database using satellite imagery, as well as of examining appropriate spatial resolutions for objects of interest.

• Korean Business Review
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• v.19 no.2
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• pp.261-274
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• 2006

Airline business operates in the 21st century within fast changing market environment and fierce competition. Management of airline companies has faced the need for vast adaptation to new trends in the growth of world economy that are cardinal changes in marketing environment due to quick development of Internet and IT, transport price competition and, as a consequence, low profit margin, diversified customer wants and needs, lack of investment needed for new aircraft equipped with the latest high tech innovations, unpredictable oil price changes, and exchange rate fluctuations. This study is aimed to evaluate the quality performance of cabin service, to analyse, further, the issues that appeared to be the most significant among customers' answers to questionnaire, to explore the relationships between these issues and customer satisfaction, to highlight the essential questions to address, and to provide some practical suggestions. The five dimensions (such as tangible, reliability, responsiveness, assurance, and empathy) were adopted to examine the relationship between the service quality and customer satisfaction of Mongolian and non-Mongolian passengers travelling by the MIAT. According to findings of analysis made with use of the SERVPERF model, it can be concluded that Mongolian travellers' satisfaction was effected by 'Tangible' and 'Responsiveness' dimensions of service quality, whereas the 'Empathy' dimension has more impact on the satisfaction of non-Mongolian.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.149-158
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• 2005

This paper describes design, fabrication, and application of the silicon based temperature controllable micro reactor. In order to achieve fast temperature variation and low energy consumption, reaction chamber of the micro reactor was thermally isolated by etching the highly conductive silicon around the reaction chamber. Compared with the model not having thermally isolated structure, the thermally isolated micro reactor showed enhanced thermal performances such as fast temperature variation and low energy consumption. The performance enhancements of the micro reactor due to etched holes were verified by thermal experiment and numerical analysis. Regarding to 42 percents reduction of the thermal mass achieved by the etched holes, approximately 4 times faster thermal variation and 5 times smaller energy consumption were acquired. The total size of the fabricated micro reactor was $37{\times}30{\times}1mm^{3}$. Microchannel and reaction chamber were formed on the silicon substrate. The openings of channel and chamber were covered by the glass substrate. The Pt electrodes for heater and sensor are fabricated on the backside of silicon substrate below the reaction chamber. The dimension of channel cross section was $200{\times}100{\mu}m^{2}$. The volume of reaction chamber was $4{\mu}l$. The temperature of the micro reactor was controlled and measured simultaneously with NI DAQ PCI-MIO-16E-l board and LabVIEW program. Finally, the fabricated micro reactor and the temperature control system were applied to the thermal denaturation and the trypsin digestion of protein. BSA(bovine serum albumin) was chosen for the test sample. It was successfully shown that BSA was successfully denatured at $75^{\circ}C$ for 1 min and digested by trypsin at $37^{\circ}C$ for 10 min.

• Journal of the Economic Geographical Society of Korea
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• v.6 no.2
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• pp.443-470
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• 2003

This study is to consider economic, political, socio-cultural and environmental characteristics of the new urbanization process and its spatial structures and urban policy of Seoul in the 1990s. Some experimental findings which have been identified throughout this study can be summarized as follows. First of all, Seoul, the largest city in S.Korea has experienced a restructuring process of economy, which has been promoted by the development of producer services as well as knowledge- based or high tech industries. Secondly, the autonomy of Seoul has increased after the introduction of local self-government, with relatively higher self-management of local finance than other cities, strengthening the tendency of enterpreneurialism, empowering civil movements, and increasing the political participation of women. Thirdly, in the socio-cultural aspect, the material wants to gain a certain identity through consumption, using urban environments culturally, varying consuming attitudes and ways of leisure times in relation with the rapid development of transportation and information communication. Fourthly, in the environmental aspect, Seoul has tried to introduce the concept of sustainable development in terms of increasing wants on the quality of life, and to develop a pro-environmental eco-city with environmental rehabilitation, constructing green space and eco-park. Finally, in the spatial dimension, Seoul has shown a structuration of multi-centers, with highly spectacular urban landscapes and seemingly authentic urban planning. These results make us confirm that Seoul has been in the process of new urbanization which can be distinguished from the previous one.