• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.323-334
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• 2008

Present study examined the functionality of the solitary wave (tsunami) control of the two-rowed porous submerged breakwater by numerical experiments, using a numerical wave tank which is based on the Navier-Stokes equation to explain fluid fields and uses a Volume of Fluid (VOF) method to capture the free water surface. Solitary wave was generated by the internal wave source installed within the computational zone in the numerical wave tank and its wave transformations by structure were compared with those in the previous study. Comparisons with the precious numerical results showed a good agreement. Based on these results, several tow-dimensional numerical modeling investigations of the water fields, including wave transformations, reflection, transmission and energy flux, by the one- and two-rowed permeable submerged breakwater under solitary waves were performed. Even if, it is a research of the limited scope, in case of two-rowed permeable submerged breakwater with $h_0/h=0.925$ ($h_0$ is height of submerged breakwater and h is water depth), the wave height damping in range of $l/L_{eff}>0.4$($L_{eff}$ is effective distance of solitary wave) can reach nearly 60% of the incident wave height. In addition, it is found that reflection coefficient increases nearly 47% and transmission coefficient decreases nearly 18% than one-rowed one. The numerical results revealed that the tow-rowed submerged breakwater can control the incident solitary wave economically and more efficiently than the one-rowed one.

• Journal of Navigation and Port Research
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• v.48 no.3
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• pp.192-199
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• 2024

Wave overtopping is a significant natural hazard that occurs in coastal areas, primarily driven by high waves, particularly those generated during typhoons, which can cause coastal flooding. The development of residential and commercial areas along the coast, driven by increasing social and economic demands, has led to a concentration of people and assets in these vulnerable areas. This, coupled with long-term sea level rise and an increase in typhoon frequency, has heightened the risk of coastal hazards. Traditionally, the evaluation of wave overtopping volumes has relied on directly measuring the collected volume of water that exceeds the crest height of structures through hydraulic model experiments. These experiments are averaged over a specific measurement period. However, in this study, we propose a new method for estimating individual wave overtopping volumes. We utilize the temporal variation of wave overtopping heights to develop an observation system that can quantitatively assess wave overtopping volumes in actual coastal areas. To test our method, we conducted hydraulic model experiments on rubble mound breakwaters, which are commonly installed along the Korean coast. We introduce wave overtopping discharge coefficients, assuming that the inundation velocity from the structure's crest is the long-wave velocity. We then predict overtopping volumes based on wave overtopping heights and compare and review the results with experimental data. The findings of our study confirm the feasibility of estimating wave overtopping volumes by applying the overtopping discharge coefficients derived in this study to wave overtopping heights.

• Korean Journal of Environment and Ecology
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• v.38 no.3
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• pp.324-337
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• 2024

Aquatic macrophytes are important factors in determining species diversity and abundance of cladocerans, but the effects of cladocerans on plant species composition or structure have not been fully considered. In South Korea, wetlands and reservoirs that are prone to covering aquatic macrophytes are scattered across the country, so it is necessary to consider on aquatic macrophytes study, when aquatic animals including cladoceran were studied. in this study, the species and abundance of cladocerans community in six microhabitat types are investigated, and based on these results, habitat conservation and efficient management are suggested. The high species numbers and abundance of cladocerans communities were found in mixed plant communities consisting of free-floating, floating-leaved, and submerged plants. The inclusion of submerged plants in plant communities contributes significantly to the complexity of habitat structures, and may increase species and abundance of cladocenran communities. This can be compared to a plant community consisting only of free-floating and floating-leaved plants in the absence of submerged plants, thereby identifying the efficiency of submerged plants. In the mixed plant communities, species diversity was the highest due to the emergence of cladoceran species (Graptoleveris testudinaria, Ilyocryptus spinifer, and Leydigia acanthococcides) absent from other plant communities. The gradual increase in the biomass (g) of submerged plants in the mixed plant communities significantly increased the species numbers and abundance of cladoceran communities (p<0.05). This is strong evidence that the increase of submerged plants in mixed plant communities has a positive effect on efficiency as a habitat for cladocerans. Although submeged plants do not contribute significantly to their landscape/aesthetic value because they are submerged in water, they have the effect of increasing species diversity in terms of biology, so they should be considered important when creating/restoring wetlands.

• Journal of Korean Elementary Science Education
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• v.43 no.1
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• pp.122-135
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• 2024

The purpose of this study was to analyze the examples presented in the "Separation of Mixtures" section of the 2015 revised science authorized textbook introduced in elementary schools in 2022 and to see how the teachers and students understand the concept. To do that, 96 keywords were extracted through three cleansing processes to separate the elements of the mixture presented in the textbook. In order to analyze the teachers' perceptions, 32 teachers at elementary schools in Gyeonggi-do received responses to a survey, and a survey of 92 fourth graders who learned the separation of the mixture with an authorized textbook in 2022 was used for the analysis. As a result, as for the solids, 54 out of 96 separations (56.3%) showed the highest ratio, and the largest number of cases were presented according to the characteristics of the development stage of students. It was followed by living things, liquids, other objects and substances, and gasses. By analyzing the mixture, the structure and the interrelationships between the 96 extracted keywords were systematized through the network analysis, and the connection between the keywords, which were a part of the mixture was analyzed. The teachers partially responded to the separation of the complex mixture presented in the textbook, but most of the students did not recognize it. Because the analysis of the teachers' and students' perceptions of the seven separate categories presented in the survey was not based on a clear conceptual perception of the separation of the mixture, but rather they tended to respond differently for each characteristic of each individual category, it was decided that it was necessary to present clearer examples of the separation of the mixture, so that the students could better understand the concept of separation of mixtures that could be somewhat abstract.

• Asia pacific journal of information systems
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• v.18 no.1
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• pp.145-162
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• 2008

One of the big concerns in e-society is privacy issue. In special, in developing robust ubiquitous smart space and corresponding services, user profile and preference are collected by the service providers. Privacy issue would be more critical in context-aware services simply because most of the context data themselves are private information: user's current location, current schedule, friends nearby and even her/his health data. To realize the potential of ubiquitous smart space, the systems embedded in the space should corporate personal privacy preferences. When the users invoke a set of services, they are asked to allow the service providers or smart space to make use of personal information which is related to privacy concerns. For this reason, the users unhappily provide the personal information or even deny to get served. On the other side, service provider needs personal information as rich as possible with minimal personal information to discern royal and trustworthy customers and those who are not. It would be desirable to enlarge the allowable personal information complying with the service provider's request, whereas minimizing service provider's requiring personal information which is not allowed to be submitted and user's submitting information which is of no value to the service provider. In special, if any personal information required by the service provider is not allowed, service will not be provided to the user. P3P (Platform for Privacy Preferences) has been regarded as one of the promising alternatives to preserve the personal information in the course of electronic transactions. However, P3P mainly focuses on preserving the buyers' personal information. From time to time, the service provider's business data should be protected from the unintended usage from the buyers. Moreover, even though the user's privacy preference could depend on the context happened to the user, legacy P3P does not handle the contextual change of privacy preferences. Hence, the purpose of this paper is to propose a mutual P3P-based negotiation mechanism. To do so, service provider's privacy concern is considered as well as the users'. User's privacy policy on the service provider's information also should be informed to the service providers before the service begins. Second, privacy policy is contextually designed according to the user's current context because the nomadic user's privacy concern structure may be altered contextually. Hence, the methodology includes mutual privacy policy and personalization. Overall framework of the mechanism and new code of ethics is described in section 2. Pervasive platform for mutual P3P considers user type and context field, which involves current activity, location, social context, objects nearby and physical environments. Our mutual P3P includes the privacy preference not only for the buyers but also the sellers, that is, service providers. Negotiation methodology for mutual P3P is proposed in section 3. Based on the fact that privacy concern occurs when there are needs for information access and at the same time those for information hiding. Our mechanism was implemented based on an actual shopping mall to increase the feasibility of the idea proposed in this paper. A shopping service is assumed as a context-aware service, and data groups for the service are enumerated. The privacy policy for each data group is represented as APPEL format. To examine the performance of the example service, in section 4, simulation approach is adopted in this paper. For the simulation, five data elements are considered: $\cdot$ UserID $\cdot$ User preference $\cdot$ Phone number $\cdot$ Home address $\cdot$ Product information $\cdot$ Service profile. For the negotiation, reputation is selected as a strategic value. Then the following cases are compared: $\cdot$ Legacy P3P is considered $\cdot$ Mutual P3P is considered without strategic value $\cdot$ Mutual P3P is considered with strategic value. The simulation results show that mutual P3P outperforms legacy P3P. Moreover, we could conclude that when mutual P3P is considered with strategic value, performance was better than that of mutual P3P is considered without strategic value in terms of service safety.

• The Korean Journal of Pesticide Science
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• v.8 no.3
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• pp.151-161
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• 2004

Three dimensional quantitative structure-activity relationships (3D-QSAR) studies for the protox inhibition activities against root and shoot of rice plant (Orysa sativa L.) and barnyardgrass (Echinochloa crus-galli) by a series of new A=3,4,5,6-tetrahydrophthalimino, B=3-chloro-4,5,6,7-tetrahydro-2H-indazolyl and C=3,4-dimethylmaleimino group, and R-group substituted on the phenyl ring in 1-(5-methyl-3-phenylisoxazolin-5-yl)methoxy-2chloro-4-fluorobenzene derivatives were performed using comparative molecular field analyses (CoMFA) methodology with Gasteiger-Huckel charge. Four CoMFA models for the protox inhibition activities against root and shoot of the two plants were generated using 46 molecules as training set and the predictive ability of the each models was evaluated against a test set of 8 molecules. And the statistical results of these models with combination (SIH) of standard field, indicator field and H-bond field showed the best predictability of the protox inhibition activities based on the cross-validated value $r^2_{cv.}$ $(q^2=0.635\sim0.924)$, conventional coefficient $(r^2_{ncv.}=0.928\sim0.977)$ and PRESS value $(0.091\sim0.156)$, respectively. The activities exhibited a strong correlation with steric $(74.3\sim87.4%)$, electrostatic $(10.10\sim18.5%)$ and hydrophobic $(1.10\sim8.30%)$ factors of the molecules. The steric feature of molecule may be an important factor for the activities. We founded that an novel selective and higher protox inhibitors between the two plants may be designed by modification of X-subsitutents for barnyardgrass based upon the results obtained from CoMFA analyses.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.82-88
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• 2005

3D QSAR studies for the fungicidal activities against resistive phytophthora blight (RPC; 95CC7303) and sensitive phytophthora blight (Phytopthora capsici) (SPC; 95CC7105) by a series of new 2-alkoxyphenyl-3-phenylthioisoindoline-1-one derivatives (X: A=propynyl & B=2-chloropropenyl) were studied using comparative molecular field analyses (CoMFA) methodology. The CoMFA models were generated from the two different alignment, atom based fit (AF) alignment and field fit (FF) alignment. The atom based alignment exhibited a higher statistical results than that of field fit alignment. The best models, A3 and A7 using combination fields of H-bond field, standard field, LUMO and HOMO molecular orbital field as additional descriptors were selected to improve the statistic of the present CoMFA models. The statistical results of the two models showed the best predictability of the fungicidal activities based on the cross-validated value $q^2\;(r^2_{cv.}=RPC:\;0.625\;&\;SPC:\;0.834)$, non cross-validated value $(r^2_{ncv.}=RPC:\;0.894\;&\;SPC:\;0.915)$ and PRESS value (RPC: 0.105 & SPC: 0.103), respectively. Based on the findings, the predictive ability and fitness of the model for SPC was better than that of the model for RPC. The fugicidal activities exhibited a strong correlation with steric $(66.8{\sim}82.8%)$, electrostatic $(10.3{\sim}4.6%)$ and molecular orbital field (SPC: HOMO, 12.6% and RPC: LUMO, 22.9%) factors of the molecules. The novel selective character for fungicidal activity between two fungi depend on the positive charge of ortho, meta-positions on the N-phenyl ring and size of hydrophilicity of a substituents on the S-phenyl ring.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.3
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• pp.81-92
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• 2019

This study was conducted to establish vegetation structure characteristics and vegetation management plan of the cultural landscape forests located around Unmun Temple in Cheongdo-gun and to provide the basic data needed to manage the cultural landscape forests. The landscape characteristics are analyzed in two perspectives including the landscape as viewed from inside and outside of Unmun Temple and eight landscape views are selected. Main views are Pinus densiflora forest and Abies holophylla forest around Unmun Temple. As a result of the survey of existing vegetation around Cheongdo-gun Unmun Temple, P. densiflora forests and P. densiflora-A. holophylla forests are widely distributed, occupying 79.2% of the forest. The plant community structure was classified into seven types according to the three topographic characteristics, flat forests, slope forests, and lower forests, Which were divided into a total of 30 survey plots and the average relative importance percentage was determined. The P. densiflora community on the flat are dominated by Carpinus tschonoskii in Under-canopy. The P. densiflora-A. holophylla community on the flat had a relatively high rate of domination in the shrubs. There were no competing species for the A. holophylla community on the plat. The large standard P. densiflora and the small standard P. densiflora were expected to be confined by P. serrulata var. pubescens and the Quercus variabilis on the slopes. The managed P. densiflora community had a relatively high rate of P. densiflora domination in the shrubs. The P. densiflora community on the lowland was dominated by Styrax japonicus and P. serrulata var. pubescens. The Shannon species diversity index was 0.2360 to 1.4088. The results of the correlation analysis with P. densiflora, A. holophylla and other species were P. densiflora had negative correlation with Acer mono, Corylus heterophylla var. heterophylla, Zelkova serrata and A. holophylla, and A. holophylla have negative correlation with S. japonicus and P. densiflora. Landscape characteristics and plant community structures are analyzed to propose management methods of maintaining and restoring The P. densiflora and A. holophylla cultural forest landscapes around Unmun Temple.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.677-684
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• 2000

This study was conducted to investigate the relationship of development of root and soil condition and also to elucidate the difference between stands for mechanical and physical stability according to distribution of roots in the Norway Spruce (Picea abies [L.] Karst.) stands of 30 to 40 year of ages with different soil condition. In the root structure, remarkably different root pattern was shown among the three stands; Eberg$\ddot{o}$tzen stand showed large number f roots with much fine roots which deeply in vertical direction while Barbis stands had thicker root and small number of root than Eberg$\ddot{o}$tzen stand. The Weidenbrunnen stand showed differently half-vertical and plate root structure and the root developed not to be deeply compared to the other two stands. In the total number of root, Eberg$\ddot{o}$tzen stand had the most number of 74 and Barbis stand 33, Weidenbrunnen stand 57 respectively. Eberg$\ddot{o}$tzen stand had much more number of vertical root with 57 than the other two stand; Barbis 21 and Weidenbrunnen 36. In the total length of root, Weidenbrunnen stand showed to be longer than the other two stands and the length of horizontal root also showed longer. Regarding to the rates of horizontal root against vertical root, Eberg$\ddot{o}$tzen stand showed comparatively higher value as 1,2 than other two stands(0.5). In the total weight of root, Weidenbrunnen stand showed very high value compared with the other stands and ratio of vertical root against horizontal root was 0,16 which is very lower than the other two stands(0,4). The remarkable differences of root pattern of Norway spruce stands appeared in this study are through to be caused more by chemical property of soil such as acidity den the mechanical or physical factor of soil conditions.

• Korean Journal of Environment and Ecology
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• v.16 no.3
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• pp.321-337
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• 2002

This study was carried out to draw up the planting plan of bridge type ecological corridor for animals migration at Hakgogae(ridge) destroyed by road construction in Yongin, Gyeonggi-do, South Korea. It was conducted with two steps, survey and planting master plan. We surveyed the structure of topography, plant community, and animal habitat. We also selected the target species migrate ecological corridor and suggested a concept of each planting area, the planting species, and the planting density based on the analyzed data and finally drew up the planting plan. The structure of topography was a steep slope due to the mountain ridge destruction so the bridge type ecological corridor was could be applied in this study and we supposed that the animals migrate along the both edge of corridor. As the results of analyzed plant community structure in two sides, the dominant woody species, Quercus serrata and Q. variabilis were distributed on the bottom and the belly of a mountain, while Pinus densiflora community was distributed on the mountain ridge as edaphic climax. The similarity between Q. serrata -Q. mongolica -Q. variabilis community on the West of survey site and Q. serrata -Q. mongolica community on the East of survey site was high in 71.0 percentages. As the results of surveying birds and some mammalia, seven species and fifty-seven individuals of birds were founded in survey area, and two species and two individuals of rodents were founded. We selected birds and some mammals for the migration species that supposed to migrate ecological corridor in drawing up the planting plan. And then we divided the planting areas into bird corridor and habitat, and mammals corridor, also suggested the planting areas in detail as follows: community planting area of shrub at slope adjacent to the bridge exit as a buffer zone, screen planting area, community planting area of herb at steep slope connected with mountain areas, inducement planting area of the animals, community planting area for bird migration, community planting area for mammals migration, and community planting area for bird habitat. We selected the planting woody species which were the constancy ratio based on the analyzed data of plant community around mountain areas was high, and suggested the planting master plan each space.