• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.1
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• pp.38-44
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• 2007

Using the mathematical model suggested by Bennet et al.(1992), the reflection and transmission coefficients by a circular pile breakwater has been investigated in the framework of potential theory. Flow separation due to sudden contraction and expansion is generated and is the main cause of significant energy loss. Therefore, evaluation of exact energy loss coefficient is critical to enhance the reliability of mathematical model. To obtain the energy loss coefficient, 2-dimensional turbulent flow is analyzed using the FLUENT commercial code. The energy loss coefficient can be obtained from the pressure difference between upstream and downstream. Energy loss coefficient is the function of porosity and the relation equation between them is suggested throughout the curve fitting processing. To validated the suggested relation, comparison between the analytical results and the experimental results is made for four different porosities with good agreement.

• The Journal of Korean Medical History
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• v.28 no.2
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• pp.47-58
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• 2015

Objectives : The purpose of this study was to investigate Wang Lun (王綸)'s assertion on Ginseng and Astragali Radix and its related arguments that had shown critical or advocative point of views about Wang lun's theory. It was expected that this study would help understand the history of arguments on the usage of Ginseng and Astragali Radix that had been triggered by Wang lun's assertion. Methods : In the process of investigation, this study first looked into the assertions of Wang Lun and the representative arguments about it, which includes Yu Tuan, Wang Ji (汪機), Sun Yikui (孫一奎). And secondly, this study also examined the other following additional arguments that had shown the conclusional aspects of this disputes. Results & Conclusions : Wang Lun (王綸)'s assertion on Ginseng and Astragali Radix proclaimed that in the symptoms of fevers in lung or lack of blood (血) the use of Ginseng and Astragali Radix must be prohibited. This assertion later faced severe criticism by opposers like Yu Tuan, Wang Ji. These opposers asserted that Yang (陽) has the ability of creating Yin (陰), and Ginseng and Astragali Radix could be the right drugs to the symptoms by lack of Yin. But a few approvers like Sun Yikui (孫一奎) had tried to advocate Wang Lun's assertion and casted the question of true meaning of Wang Lun. And In the other following arguments, it could be said that the influence of Wang Lun's assertion had gradually waned but could have been reciprocally accepted in the opposite point of view.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.83-88
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• 2013

Progressive collapse is a chain reaction of failures propagating throughout a portion of a structure that is disproportionate to the original local failure. When column members are subjected to unexpected load (compression load), they will buckle if the applied load is greater than the critical load that induces buckling. The post-buckling strength of the columns will decrease rapidly, but if there is enough residual strength, the members will absorb the potential energy generated by the impact load to prevent progressive collapse. Thus, it is necessary to identify the relationship of the load-deformation of a column member in the progressive collapse of a structure up to final collapse. In this study, we carried out nonlinear FEM analysis and based on deflection theory, we investigated the load-deformation relationship of H-section steel columns when both ends were fixed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.19 no.1
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• pp.79-84
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• 1983

The test specimen, designated the double cantilever beam, was employed for a fracture mechanics study of stress corrosion cracking (SCC) of type 5083 Al-alloy in seawater. Stress intensities for this DCB specimen were calculated by using compliance, strain energy release rate and relation between stress intensity and strain energy release rate. Analytical expression for compliance as a function of crack length was obtained by applying beam theory. It was investigated that the polarization potentials affected the growth rate and surface of stress corrosion cracking. The results are as follows, The critical stress intensity was 134.81-148.38kg/mm super(3/2) and K sub(Ii) under polarization potentials was 75.92-145.78kg/mm super(3/2). The minimum stress corrosion crack growth rate was occurred at-987mV SCE. Insoluble compound on $\beta$ phase was looked into through SCC. The greater anodic potential is, the larger insoluble compound on $\beta$ phase becomes.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.606-614
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• 2006

The conventional on-demand mobile ad hoc routing algorithms (DSR and AODV) initiate route discovery only after a path breaks, incurring a significant cost and time in detecting the disconnection and establishing a new route. In this theory, we investigate adding proposed pro-active route selection and maintenance to the conventional on-demand mobile ad hoc routing algorithms(DSR and AODV). The key idea is to be only considered likely to be a path break when the received packet power becomes close to the minimum critical power and to be generated the forewarning packet when the signal power of a received packet drops below a optimal threshold value. After generated the forewarning packet, the source node can initiate rout discovery in advance; potentially avoiding the disconnection altogether. Our extensive simulation study shows that the proposed advance-active route selection and maintenance algorithms outperforms the conventional on-demand routing protocol based on DSR and AODV in terms of packet delivery ratio, packet latency and overhead.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.2
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• pp.75-86
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• 2002

The selection of the optimal checkpointing interval has been a very critical issue to implement a checkpointing recovery scheme for the fault tolerant distributed system. This paper presents a new scheme that allows a process to select the proper checkpointing interval dynamically. A process in the system evaluates the cost of checkpointing and possible rollback for each checkpointing interval and selects the proper time interval for the next checkpointing Unlike the other scheme, the overhead incurred by both of the checkpointing and rollback activities are considered for the cost evaluation and current communication pattern is reflected in the selection of the checkpointing interval. Moreover, the proposed scheme requires no extra message communication for the checkpointing interval selection and can easily be incorporated into the existing checkpointing coordination schemes.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.300-308
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• 2009

This article analyzed the crisis and emergency management research trend in the field of public administration in Korea from 1987 to 2007. The research purpose of this paper is to empirically evaluate the state of art in the crisis and emergency management research trend and explore research topics and methodology for future studies. According to empirical analysis, the main research results are as follows. First, almost all research papers over 80% have been written after 1998 and, especially, 67.6% of all papers have been published from 2003-2007. Second, recently lots of scholars are more interested in the problem solving prescriptive topics than normative and theory orientation. Third, in the Korean public administration, 74.6% of research papers which dealt with crisis, have investigated the disaster crisis including natural and man-made disasters, among conventional security crisis, disaster crisis, critical infrastructure crisis, and living safety crisis. Finally, so far, crisis and emergency management research trend in Korean public administration have consisted mainly of the papers with more descriptive approach and literature survey than empirical approach and survey research.

• The Journal of Art Theory & Practice
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• no.3
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• pp.9-34
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• 2005

Contemporary Korean art in the 1960s and the 1970s reflects the social and political contexts in Korea from the 5 16 revolution through the Yoo Shin period. This paper investigates whether art has been free from power or not. It examines the power embedded in contemporary Korean art in the 1960s and the 1970s. This paper examines the historical moments of the Korean Art Exhibition, focusing on the complications between the abstract and figurative artworks of the 1960s. One of the significant art exhibitions since the 8 15 liberation of Korea, the Korean Art Exhibition witnessed conflict among Korean artists who wanted to have power in the art world of Korea. Institutional contradiction based on factionalism and conservatism prevailed in the Korean Art Exhibition was attacked by the avant-garde young artists in the 1960s. With the contact of Abstract Expressionism, young artists' generation participated in the The Wall Exhibition. This exhibition challenged and established moral principles and visualized individual expression and creation similar to the Informal movement in the West. In the world of the traditional painting of Korea, the Mook Lim Exhibition of 1960, organized by young artists of traditional painting, advocated the modernization of Soo Mook paintings. Additionally, abstract sculptures in metal engraving were the new trends in the Korean Art Exhibition. In the 1970s, the economic development and establishment of a dictatorial government made the society stiffen. Abstract expression died out and monochrome painting was the most influential in the 1970s. After the exhibition of Five Korean Artists, Five White Colors in the Tokyo Central Art Museum in 1976, monochrome paintings were formally discussed in Korea. 'Flatness' 'physicality of material' 'action' 'post-image' 'post-subjectivity' and 'oriental spirituality' were the critical terms in mentioning the monochrome paintings of the 1970s. 'Korean beauty' was discussed, focusing on the beauty of white which was addressed by not only Yanagi Muneyoshi but also the policy of national rehabilitation under the Yoo Shin government. At this time, the monochrome paintings of the 1970s in Korea, addressing art for art's sake, cutting of communication with the masses, and elitism, came to be authorized.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.2
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• pp.65-74
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• 2002

Recently star networks are considered as attractive alternatives to the widely used hypercube for interconnection networks in parallel processing systems by many researchers. One of the fundamental communication problems on star graph networks is broadcasing In this paper we consider the broadcasting problems in star graph networks using wormhole routing. In wormhole routed system minimizing link contention is more critical for the system performance than the distance between two communicating nodes. We use Hamiltonian paths in star graph to set up link-disjoint communication paths We present a broadcast algorithm in n-dimensional star graph of N(=n!) nodes such that the total completion time is no larger than $([long_n n!]+1)$ steps where $([long_n n!]+1)$ is the lower bound This result is significant improvement over the previous n-1 step broadcasting algorithm.

• Computers and Concrete
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• v.25 no.4
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• pp.311-325
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• 2020

In this research work, the hygrothermal and mechanical buckling responses of simply supported FG sandwich plate seated on Winkler-Pasternak elastic foundation are investigated using a novel shear deformation theory. The current model take into consideration the shear deformation effects and ensures the zero shear stresses on the free surfaces of the FG-sandwich plate without requiring the correction factors "Ks". The material properties of the faces sheets of the FG-sandwich plate are assumed varies as power law function "P-FGM" and the core is isotropic (purely ceramic). From the virtual work principle, the stability equations are deduced and resolved via Navier model. The hygrothermal effects are considered varies as a nonlinear, linear and uniform distribution across the thickness of the FG-sandwich plate. To check and confirm the accuracy of the current model, a several comparison has been made with other models found in the literature. The effects the temperature, moisture concentration, parameters of elastic foundation, side-to-thickness ratio, aspect ratio and the inhomogeneity parameter on the critical buckling of FG sandwich plates are also investigated.