• Journal of the Korean Geographical Society
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• v.48 no.6
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• pp.944-966
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• 2013

This study attempts to highlight the cultural importance of urban public space by analyzing the changes Tap-Gol Park from late 1990's to early 2000's, a park located in the heart of Seoul, underwent in its meanings and uses. Public space, a product of modern urban planning, is characterized by its openness and accessibility and represents the vitality of modern city, serving as a meeting place for citizens with different social backgrounds at such occasions as gatherings and festivals. While the government or a few dominant groups try to control the public and their behavior in public space by giving a specific meaning to it and specifying its use, people constantly set their foot in it and view the space as a place differently for each individual's personal or social reasons. It is therefore not very surprising that the meaning of public space has never been successfully defined. Following the traces of attempts to define the meaning of public space and considering how public space can be efficiently used will shed light on what types of groups, especially ages and classes participated in the contest for the use of public space and expressed their own cultures in urban society through various negotiations.

• Journal of Korean Home Economics Education Association
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• v.20 no.2
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• pp.1-14
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• 2008

This study was performed to evaluate the effect of the e-Learning application on the teaching learning method in Technology-Home Economics of Middle School. For e-Learning of clothing part, diverse teaching programs and contents were reconstructed and provided in cyber-space. Among the uploaded diverse materials including advanced and supplementary materials, students could make a choice which depends on their own levels. Since the results of assignments could be uploaded in cyber-space and easily accessible to all students, the reliablity of estimation was increased and self-directed learning ability was improved. Also, more effective teaching learning activity could be expected through the mutual exchange of opinion between students and teacher, and among students. Besides, counselling and advices on overall aspect of student's life were also possible. The students were generally satisfied to e-Learning instruction. The interest and understanding about clothing part were increased, and the academic attitude and habit were positively changed. Also they responded that e-Learning instruction were very helpful because learning was possible even after school, diverse materials for learning were available, and submitting the results of assignments was very convenient. In conclusion, the application of e-Learning on the teaching learning method was very effective and should be encouraged. The development and supplement of diverse programs and contents will be necessary for more successful e-Learning instructions.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.131-136
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• 2008

Silica- or titania-filled poly (vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolytes were prepared by phase inversion technique using N-methyl-2-pyrrolidone and dimethyl acetamide as solvent and water as non-solvent. The polymer electrolytes were adopted to the lithium metal polymer battery using high-capacity cathode $Li[Ni_{0.15}Co_{0.10}Li_{0.20}Mn_{0.55}]O_2$ and lithium metal anode. After the repeated charge-discharge test for the cell, it was proved that the cell adopting the polymer electrolyte based on the phase-inversion membrane containing 40~50 wt% silica showed the highest discharge capacity (180 mAh/g) until 80th cycle and then abrupt capacity fade was just followed. The capacity fade might be due to the deposition of lithium dendrite on the polymer electrolyte, in which the capacity retention was no longer sustainable.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.127-131
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• 2008

Ambrosia beetle, Platypus koryoensis, is a vector of oak wilt disease caused by Raffaelea sp. in Korea. The degree of damage by oak wilt disease was dependent on the density of the beetles in the oak trunk, a relationship between the degree of damage by oak wilt disease and the density of beetle on the basis of the number of entry hole was studied. Entry hole distribution within tree trunk was analyzed by the nearest neighbor method. Thirty four oak trees (Quercus mongolica) located in survey area were selected and then degree of damage, the number of attack hole/$623cm^2$ in upper (50cm from the surface) and lower (surface) trunk and the nearest neighbor distance between the holes were measured. The number of hole and the nearest neighbor distance in upper and lower part were positively correlated with each other. As the degree of damage was severer, the number of the holes increased, whereas the nearest neighbor distance decreased. The distribution pattern of the hole was changed from clumped one to uniform as the severity of damage increased. These results suggested that Platypus koryoensis attacked the oak tree in concentrative manner at initial stage of attack but at final stage, it distributed uniformly to reduce intraspecific competition between the beetles.

• Korean Journal of Plant Taxonomy
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• v.47 no.2
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• pp.137-153
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• 2017

Fruit and seed morphological characteristics were investigated in 36 taxa of 20 genera of Korean Ranunculaceae. As a result, fruits were classified as the achene, berry, or follicle type. In the taxa with achene, the presence of trichomes and stoma on the surface of the fruit and a feature in which the endocarp distinctively develops into a one-layer sclereid were considered as useful characteristics. Moreover, in the taxa with follicles, the composition of the seed coat (bitegmic vs. unitegmic), the cell shape of the seed coat, the presence of trichomes, and the type of seed coat were useful for taxonomic characteristics in Korean Ranunculaceae. Based on the fruit and seed characteristics, Adonis is likely to be classified into Helleboroideae rather than Ranunculoideae, as it has bitegmic ovules. In addition, Enemion is similar to Eranthis in unitegmic ovule and the seed coat structure which has non-sclereid exotesta; therefore, it is reasonable to be placed in Helleboroideae. According to the results of this study, more in-depth research is needed regarding the taxonomic positions of Callianthemum and Actaea, which has the only berry fruit type.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.219-223
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• 2005

Torymus geranii was found to be a ectoparasitoid attacking the larvae of Dryocosmus kuriphilus. T. geranii has longevity of a $42.8{\pm}9.8$ days at $20^{\circ}C$ and $26.5{\pm}11.0$ day at $25^{\circ}C$ under conditions supplied with 100% honeydew. Oviposition numbers at 20 and $25^{\circ}C$ were $22.3{\pm}12.5$ and $42.2{\pm}18.4$, respectively. The eggs were oval in shape, measuring $0.56{\pm}0.33$ mm in length. The larvae, $2.94{\pm}0.18mm$ in length, was white and length of male and female pupae were $2.01{\pm}0.18mm$ and $2.73{\pm}0.09mm$, respectively. T. geranii had two generations with overwintering generation emerged on late May to early June at Chunchon, central part of Korea, however showed three generations with overwintering generation emerged on middle May to early June, the first one on late June to early July, and the second one on late July to earlyl August.

• Journal of Industrial Technology
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• v.9
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• pp.21-28
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• 1989

For the study of the fatigue behavior, high-strength bolted connections on a small scale were manufactured, and carried on fatigue tests. Its experimental values were analysed by stress-fatigue life (S-N) curve. Three types of specimens : the base metal, the cireular hole and the welded sperimens had same net section were made. Through the same tests those experimental values were compared with those of the high-strength bolted conneetions. The results of these studies are as followings. It was found that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the high-strength bolted conneetions were much more about 14% and 16% than that of the base metal specimen. It was thought that this trend was due to frictional force increasing fatigue strength. It was known that fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the welded joints were less 29% and 21% than that of base metal specimen. It was thought that that trend was due to weld flaw. It was appeared that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the high-strength bolted connections were much more about 38% and 30% than that of welded joint. It was thought that it was due to both frictional force increasing the fatigue strength in bolted connections and weld flaw decreasing the fatigue strength in welded connections. It was found that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the B3 specimens were much more 2% and -2% than that of the B4 specimen. It was thought that that trend was due to the frictional force, which concerned with shape of specimen. It was known that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the specimen with circular hole was less 61% and 65% than that of base metal. It was known that the allowable stress for bolted joint was higher than that of welded Joints. If that research is continued and more data are accumulated it can be expected that a basic pattern to provided the indicator of the fatigue design of the bolted connections of steel structures and persume the safety and lifeproof of existing structures is given.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.295-300
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• 2020

Since China opened its door to the world in 1978, its economic development had been concentrated in the Eastern and Western area compared with the middle area. From 2000s, the Chinese government started to develop the middle area in terms of balanced development. With this goal, "Plan on Zhengzhou Airport Economy Zone", and "One Belt and One Road" has implemented in Zhengzhou, where is the an important traffic center in middle area. Meanwhile, the foreign trade of Zhengzhou has been increased about 10 times between 2009 and 2018. In particular, its growth is the fastest among six central cities in 2018 from the lowest in 2009. This study investigates whether the Chinese government policy has an effect on the foreign trade of Zhengzhou. We find that based on the regression analysis of the Principal Component Analysis (PCA), the government policies has a positive impact on the development of Zhengzhou's foreign trade. It is meaningful that the government policy focused on the advantage of Zhengzhou contributes its development of foreign trade.

• Proceedings of the International Union of Geodesy And Geophysics Korea Journal of Geophysical Research Conference
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• 2003.05a
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• pp.20-20
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• 2003

In the summers of 1997 and 1998 and in February of 2000 we made 570 measurements of the ambient geomagnetic field 120 cm above the pavement surface of State Route 130, south of Pahoa, the island of Hawaii using a three-component fluxgate magnetometer. We measured at every 15.2 m (50 feet) interval covering a distance of 6, 310 m (20, 704 ft) where both historic and pre-historic highly magnetic basalt flows underlie. We also collected 197 core samples from eight road cuts, 489 specimens of which were subject to AF demagnetizations at 5 - 10 mT level up to a maximum field of 60 mT. We observed significant inclination anomalies ranging from a minimum of $31^{\circ}$ to a maximum $40^{\circ}$ where a uniform inclination value of $36.7^{\circ}$ (International Geomagnetic Reference Field, IGRF) was expected. Since the mean of the observed inclinations is approximately $35^{\circ}$ we assume that the study area is slightly affected by the magnetic terrain effect to a systematically shallower inclinations for being located in the regionally sloping surface of the southern side of the island (Baag, et al., 1995). We observed inclination anomalies showing wider (spacial) wavelength (160 - 600 m) and higher amplitudes in the historic lava flows area than in the northern pre-historic flows. Our observations imply that preexisting inclination anomalies such as those that we observed would have been interpreted as paleosecular variation (PSV). These inclination anomalies can best be attributed to concealed underground highly magnetic dikes, channel type lava flows, on-and-off hydrothermal activities through fissure-like openings, etc. Both the within- and between-site dispersions of natural remanent magnetization (NRM) are largest (up to ${\pm}7^{\circ}$) above the flows of 1955, while the area of pre-historic flows in the northern part of the study area exhibit the smallest dispersion. Nevertheless, mean inclinations of each historic flow of 1955 and 1790 are almost identical to that of the corresponding present field, whereas mean of NRM (after AF demagnetization) inclinations for each of the four pre-historic lava flow units is twelve to thirteen degrees lower than the present field inclination. We observed three cases of very large inclination variations from within a single flow, the best fitting curves of which are linear, second and third order polynomials each from within a single flow, whereas no present field variations are observed. This phenomena can be attributed to the notion that local magnetic anomalies on the surface of an active volcano are not permanent, but are transient. Therefore we believe that local magnetic anomalies of an active volcano may be constantly modified due to on going subsurface injections and circulations of hot material and also due to wide spacial and temporal distribution of highly magnetic basaltic flows that will constantly modify the topography which will in turn modify the local ambient geomagnetic field (Baag, et al., 1995). Our observations bring into question the general reliability of PSV data inferred from volcanic rocks, because on-going various geologic and geophysical activities associated with active volcano would continuously deflect and modify the ambient geomagnetic field.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.191-201
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• 2016

A stochastic process has been used to develop a condition-based model for preventive maintenance of armor units of rubble-mound breakwaters that can make a decision the optimal interval at which some repair actions should be performed under the perfect maintenance. The proposed cost model in this paper based on renewal reward process can take account of the interest rate, also consider the unplanned maintenance cost which has been treated like a constant in the previous studies to be a time-dependent random variable. A function for the unplanned maintenance cost has been mathematically proposed so that the cumulative damage, serviceability limit and importance of structure can be taken into account, by which a age-based maintenance can be extended to a condition-based maintenance straightforwardly. The coefficients involved in the function can also be properly estimated using a method expressed in this paper. Two stochastic processes, Wiener process and gamma process have been applied to armor stones of rubble-mound breakwaters. By evaluating the expected total cost rate as a function of time for various serviceability limits, interest rates and importances of structure, the optimal period of preventive maintenance can easily determined through the minimization of the expected total cost rate. For a fixed serviceability limit, it shows that the optimal period has been delayed while the interest rate increases, so that the expected total cost rate has become lower. In addition, the gamma process tends to estimate the optimal period more conservatively than the Wiener process. Finally, it is found that the more crucial the level of importance of structure becomes, the more often preventive maintenances should be carried out.