• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.1
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• pp.70-76
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• 2008

Periodic cellular metals (PCMs) are actively being investigated because of their excellent specific strength and stiffness, and multi-functionality such as a heat disperse structure bearing external loading. The Kagome truss PCM has been proved that it has higher resistance to plastic buckling and lower anisotropy than other truss PCMs. In this paper, the out-of-plane compressive responses of the WBK specimens have been measured, theoretically predicted and numerically analyzed. Three specimens of two-layered WBK are fabricated and tested for measuring the responses. The peak stress of compressive behavior and effective elastic modulus are predicted based on the equilibrium equation and elastic energy conservation. Moreover, the structure of the specimen is modeled using the commercial mesh generation code, PATRAN and the finite element analysis for the model under the compression is carried out using the commercial FE code, ABAQUS. Finally, the obtained results are compared with each other to analyze the compressive characteristics of Wire-woven Bulk Kagome (WBK).

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.456-463
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• 2009

The preconsolidation pressure has been commonly determined by oedometer test. However, it can also be determined by in-situ test, such as piezocone test with theoretical and(or) empirical correlations. Recently, Neural Network(NN) theory was applied and some models were proposed to estimate the preconsolidation pressure or OCR. However, since the optimization process of synaptic weights of NN model is dependent on the initial synaptic weights, NN models which are trained with different initial weights can't avoid the variability on prediction result for new database even though they have same structure and use same transfer function. In this study, Committee Neural Network(CNN) model is proposed to improve the initial weight dependency of multi-layered neural network model on the prediction of preconsolidation pressure of soft clay from piezocone test result. It was found that even though the NN model has the optimized structure for given training data set, it still has the initial weight dependency, while the proposed CNN model can improve the initial weight dependency of the NN model and provide a consistent and precise inference result than existing NN models.

• The Journal of Korean Medical History
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• v.28 no.1
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• pp.1-10
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• 2015

This study examines the meaning of medical-text publication in the Joseon Dynasty by applying anthropological notions of "health care system" and "popular health care sector" to the social and political contexts of the pre-modern state. The present study focuses on the social network of senders and receivers in which medical knowledge is communicated and shared. Exploring the multi-layered structure of the network among the state, the author-practitioners, and populace, this study argues that the network of knowledge sharing system by publication of medical texts itself is a core structure in the health care system of the Joseon Dynasty. This pre-modern health care system aimed to vitalize and reinforce the "popular health care sector" by sharing medical knowledge with populace through the book-publication system. Foucault's notion of "biopolitics" provides a comparative window between the modern health care system and the health care system of the Joseon period, articulating the particularity of the pre-modern health care system.

• International Journal of Highway Engineering
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• v.18 no.1
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• pp.85-90
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• 2016

PURPOSES : The objective of this paper is to understand the deterioration phenomenon and causes in the pavement of a ramp area. METHODS : Ramp areas need to be sloped because of the centrifugal force, which depends on the vehicle speed and grade of the ramp area. As a result, vertical and horizontal forces are applied on the pavement surface of the ramp area. Furthermore, the horizontal force depends on the vehicle speed and grade of the ramp area. In order to analyze the pavement structure of a ramp area, a multi-layered elastic analysis program was used to evaluate the weakest link of fatigue cracking deterioration, according to the simultaneously applied vertical and horizontal forces. RESULTS : From case studies related to the bonding conditions between the surface and base layer in a ramp area, it was found that the partially bonded cases resulted in a critical potential of fatigue cracking deterioration, in a comparison of 50%, 70%, and fully bonded cases. CONCLUSIONS : According to the results of the case studies, the pavement structure system should be reinforced by upgrading the material or increasing the thickness compared to the general pavement areas, in order to provide a performance life similar to the mainline pavements in the ramp areas.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.201-209
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• 2023

Recently, fiber-reinforced composites have been widely used in various industrials fields. In this study, the mechanical behavior, especially fracture behavior, of biomimetic fiber-reinforced composites subjected to pressure loading was analyzed using finite element analysis (FEA). The fiber alignments in the biomimetic composites formed a helicoidal structure, wherein a stacking sequence involved a gradual rotation of each ply in the multi-layered laminated composites. For comparison, cross-ply composite samples with fibers arranged at 0° and 90° were prepared and analyzed. In addition, the mechanical behavior was analyzed based on combinations of the stacking sequence of carbon-fiber composites and glass-fiber composites. The FEA results showed that, when compared with the cross-ply samples, the mechanical properties of the biomimetic composites were considerably improved under pressure loading, which was applied to one side of the composites. Thus, the biomimetic helicoidal structure significantly improved the mechanical properties of the composites. Placing materials having high elasticity and strength in the outermost layers (the layer of the side on which pressure was applied and the opposite side layer) of the composites also significantly contributed to improving the mechanical properties of the composites.

• Korean Journal of Environment and Ecology
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• v.25 no.2
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• pp.211-226
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• 2011

The purpose of this paper was to ensure the basis for effective management of Tricholoma matsutake mountain province, to perform biotope mapping of Pinus densiflora based on growth environment of Tricholoma matsutake, target a cluster of Yangyang-gun, Kang Won-do. Study Methods were to review on growth and environmental characteristics of Tricholoma matsutake through internal and external documents and to identify vegetational structure and soil characteristics. This paper studied growth structure and soil environment of Pinus densiflora forest where a farm of production area for Tricholoma matsutake of in order to set the standard of Pinus densiflora biotope. Mapping standards were derived by separating of landform conditions, soil conditions, vegetation conditions. Biotope types were divided into possible production area for Tricholoma matsutake and potential production area for Tricholoma matsutake, possible production area for Tricholoma matsutake were Pinus densiflora biotope in landform and soil structure that enables Tricholoma matsutake production and Single-layered Pinus densiflora biotope of less than 30cm(DBH)-Tree species that other shrub is dominant in shrub layer, Multi-layered Pinus densiflora biotope that Pinus densiflora forest was predominant in understrory layer. Potential production area for Tricholoma matsutake were single-layered Pinus densiflora biotope of more than 30cm(DBH) in landform that enables Tricholoma matsutake production, Pinus densiflora biotope with Quercus predominant in the understrory layer, single-layered Pinus densiflora biotope with Quercus predominant in shrub layer, inappropriate vegetation structure area that the induction of production of Tricholoma matsutake was possible through future vegetation management. According to the research results, Pinus densiflora forest were divided into 16 types; 6 types of possible Tricholoma matsutake production areas, 9 potential Tricholoma matsutake production areas and 16 types of areas where Tricholoma matsutake production was impossible. Possible production areas account for 15.48%, or $9.8km^2$ out of the total Pinus densiflora forest while potential production areas take up 32.42%, or $20.52km^2$, and areas where Tricholoma matsutake production was impossible was 52.10%, or $32.97km^2$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.891-899
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• 2013

This paper suggests a test and evaluation procedure of conformal load-bearing antenna structure(CLAS) for high speed military jet application. A log periodic patch type antenna was designed for multi-band communication and navigation antenna. Carbon/Glass fiber reinforced polymer was used as a structure supporting aerodynamic loads and honeycomb layer was used to improve antenna performance. Multi-layers were stacked and cured in a hot temperature oven. Gain, VSWR and polarization pattern of CLAS were measured using anechoic chamber within 0.15~2.0 GHz frequency range. Tension, shear, fatigue and impact load test were performed to evaluate structural strength of CLAS. Antenna performance test after every structural strength test was conducted to check the effect of structural test to antenna performance. After the application of new test and evaluation procedure to validate a new CLAS, a design improvement was found.

• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.583-594
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• 2002

Assuring the security of group communications such as tole-conference and software distribution requires a common group key be shared among the legal members in a secure manner. Especially for large groups with frequent membership change, efficient rekey mechanism is essential for scalability. One of the most popular ways to provide sealable rekey is to partition the group into several subgroups. In this paper, we propose a two-layered key management scheme which combines DEP and CBT, a protocol in which subgroup manager cannot access the multicast data and another that has a multi-core, respectively. We also select sub-group key management protocols suitable for our structure and design new rekey protocols to exclude the subgroup managers from the multicast data. Compared to previous protocols based on CBT, our scheme provides forward secrecy, backward secrecy and scalability. This would reduce the number of encryption and decryption for a rekey message and would improve the efficiency number of rekey messages and the amount of information related to group members that group managers must maintain compared to DEP.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.5
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• pp.20-30
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• 2003

This study is aimed at establishing the categories and items for ecological assessment and evaluation of the environmental friendliness of golf courses in the capital region of Korea. The categories and items for the assessment have been derived based on the existing literature and interviews with golf experts. This study covers 32 golf courses in the capital region of Korea that are available in terms of data and on-site surveys. In order to conduct a comprehensive assessment of the environmental friendliness of the golf courses, the assessment area was divided into 4 categories that include a total of 14 sub-categories. The 4 categories encompass 1) location, 2) topography, 3) vegetation, and 4) construction. As its sub-categories, the location category includes current land use and zoning in the National Land Use Management Law. Topography has 2 sub-categories in the damage ratio of existing topography, gradient, cut area, and slope height. The assessment of vegetation is largely based on site surveys in the categories of preservation of the existing vegetation, the use of natural resources and existing trees, the component ratio of native tree species, the multi-layered structure of vegetation, and the utilization of water purification plants. In the aspect of construction, afforestation on tile slopes and the utilization of existing surface soil were evaluated. The examination of comparative analysis among the 10 items as a ratio measure showed that the scores were low in the sub-categories of current land we, the use of existing trees, and the multi-layered structure of vegetation. However, the rating results were satisfactory in the 2 sub-categories including cut area, and the utilization of native tree species. Those proved to be contributing factors in the ecological health of the golf courses. According to correlation analysis of the 10 items to the overall ecological rating of each golf course, the sizes of the 32 golf courses were mainly affected by the damage ratio of existing topography, gradient, preservation of vegetation and slope height. This study has the initiative to conduct an ecological assessment of golf courses in the country based on site surveys. The study results revealed that location factors such as current land use, damage ratio of topography and gradient and topographical factors were the main factors affecting the environmental friendliness of golf courses. This indicates indicating the significance of these factors in the future construction practices of golf courses. Furthermore, this study raises the need for follow-up studies to establish more detailed assessment criteria and to develop assessment techniques for areas such as slope afforestation and water purification plants that need a qualitative approach.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.150-160
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• 2014

In this study, the analysis carried out on characteristic of planting species and planting density of parks and green spaces in downtown city of Haengjeong-dong in Wonju, Gangwon Province. We found that 8,050 coniferous trees (19 species), 6,037 deciduous trees (61 species) and 77,609 shrubs 103 species were planted in the parks and green space in Haengjeong-dong. However, a conifer Pinus strobus is highly concentrated in all four kinds of places which are neighborhood park, children's park, green buffer zone and landscape green space regardless of their period of construction and usage of surrounding land and other trees were planted in order of Pinus koraiensis, Prunus yedoensis, Acer palmatum, Zelkova serrata, Pinus densiflora. Average planting density of parks and green spaces is $0.03tree/m^2$ for a tall tree and $0.18tree/m^2$ for a shrub, which shows low planting density in most parks and green spaces of Wonju. Also, understory vegetation was not planted enough. Since area of lawn is wide in green spaces, planting density is needed to be increased and tall trees should be planted more. Therefore, we suggest planting more trees in an area where trees are not planted, multi-layered vegetation and increasing in planting density through shrub planting etc., by identifying spaces for trees to be planted within parks and green spaces.