• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.1
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• pp.10-21
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• 2010

Equations of chordwise and flapwise bending motions for the vibration analysis of rotating pre-twisted blades having tapered cross section and setting angle are derived by using hybrid deformation variable modeling. The two motions are couples to each other due to the pre-twisted angle of the beam cross section. The derived equations are transformed into dimensionless forms in which dimensionless parameters are identified. The effects of the dimensionless parameters on the modal characteristics of rotating pre-twisted blades having tapered cross section and orientation angle are investigated. The eigenvalue loci veering phenomena are also investigated and discussed in this work.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.288-295
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• 2009

Equations of chordwise and flapwise bending motions for the vibration analysis of rotating pre-twisted blades having tapered cross section and orientation angle are derived by using hybrid deformation variable modeling. The two motions are couples to each other due to the pre-twisted angle of the beam cross section. The derived equations are transformed into dimensionless forms in which dimensionless parameters are identified. The effects of the dimensionless parameters on the modal characteristics of rotating pre-twisted blades having tapered cross section and orientation angle are investigated. The eigenvalue loci veering phenomena is also investigated and discussed in this work.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.119-125
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• 2015

Interspecific crosses between rapeseed (Brassica napus L.) and chinese cabbage (B. campestris var. pekinensis Makino) and turnip (B. rapa L.) were made in order to examine the cross possibility and morphological phenotype of $F_1$ hybrid. The growth of pollen tube of cross between rapeseed and chinese cabbage was more rapid than cross between rapeseed and turnip. Silique formation and seed setting in silique were relatively high in the cross between rapeseed and chinese cabbage. The percentage of silique set from interspecific cross between rapeseed and chinese cabbage was 90.6% and higher 23.3% than the percentage of silique from interspecific cross rapeseed and turnip. The average number of seed per silique obtained from the cross rapeseed and chinese cabbage, and rapeseed and turnip reached 15.5 and 11.6, respectively. The morphological phenotypes of $F_1$ hybrid plants obtained from seeds in the cross between rapeseed and chinese cabbage resembled rapeseed mainly, but leaf length and leaf width were increased. The size, shape and lobation of leaves of $F_1$ hybrid plants from interspecific cross between rapeseed and turnip were intermediated between their parent species, but color of leaves was dark-green.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.6 s.336
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• pp.17-22
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• 2005

Organic-inorganic hybrid type thin films are the next generation candidates as low-k materials. SiOC films are analyzed the bonding structure by the red and blue chemical shift using the fourier transform infraredspectra. Conventional chemical shift of organic chemistry is a red shift, but hybrid type SiOC films were observed the red and blue shift. The chemical shift originates from the interaction between the C-H bond and high electronegative atoms, and the blue shift in SiOC films is caused by the porosity due to the increase of the electron rich group such as much methyl radicals. The bonding structures of SiOC films are also divided into the Si-O-C cross-link structure and the Si-O-C cage-link structure due to the chemical shifts. The Si-O-C cross-link structure progressed the adhesion attributed to the C-H bond elongation in the reason of the red shift, and the dielectric constant also decreases.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.223-228
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• 2009

Efficient service discovery mechanism is a crucial feature for a hybrid ad-hoc network supporting extension of a wireless ad-hoc network to the Internet. We propose an efficient cross-layer service discovery mechanism using non-disjoint multi-path source routing protocol for hybrid ad-hoc networks. Our scheme has advantages of multi-path routing protocol and cross-layer service discovery. Intuitively, it is not difficult to imagine that the cross-layer service discovery mechanism could result in a decreased number of messages compared to the traditional approach for handling routing independently from service discovery. By simulation, we show that faster route recovery is possible by maintaining multiple routing paths in each node, and the route maintenance overhead can be reduced by limiting the number of multiple routing paths and by maintaining link/node non-disjoint multi-path.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.201-204
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• 2005

The bond characteristics of two types hybrid FRP (fiber reinforced polymer) reinforcing bars with different rib geometry were analyzed experimentally. Two types of hybrid FRP. reinforcing bars such as spiral and cross type with different relative rib area were considered in this test. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the recommendations of CSA Standard S806-02. From the test results, it was found' that cross type hybrid FRP reinforcing bars showed the higher bond strength than that of spiral type's due to the higher relative rib area.

• Earthquakes and Structures
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• v.15 no.4
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• pp.351-360
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• 2018

Energy-based methodology is utilized to design novel timber-steel hybrid core wall system. The timber-steel core wall system consists of cross laminated timber (CLT), steel columns, angled brackets and t-stub connections. The CLT wall panels are stiff and strong, and ductility is provided through the steel t-stub connections. The structural system was modelled in SAP2000 finite element program. The hybrid system is explained in detail and validated using first principles. To evaluate performance of the hybrid core system, a 7-story building was designed using both forced-based design and energy based design (EBD) approaches. Performance of the structure was evaluated using 10 earthquakes records selected for 2500 return period and seismicity of Vancouver. The results clearly served as a good example of the benefits of EBD compared to conventional forced based design approaches.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.214-218
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• 2011

In order to survive in turbulent and competitive markets, automotive part manufacturers try efforts to develop new manufacturing technologies for ultra-lightweight, high-intensity and environmentally-friendly parts. Most of front lower arm is manufactured by welding process between upper- and lower panel which are produced by press stamping process. Because lower arm mounted on the cross member parts is one of the important complementary parts. So, to improve safety and lightweight of these parts, hybrid technologies are used in this paper. As hybrid technologies are applied to be front sub-frame, rear cross member and other chassis parts as well as front lower arm, the 20% lightweight has been achieved compared with existing steel parts.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.629-632
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• 2006

The various rib geometry of hybrid fiber reinforced polymer (FRP) reinforcing bars were analyzed by finite element method. From the analysis result, two types of hybrid FRP reinforcing bars such as spiral and cross type with the same dimension of rib geometry were fabricated in this study. To evaluate the bond properties of them, direct pull-out test was performed. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made in accordance with the recommendations of CSA Standard S806-02. From the test results, it was found that cross type hybrid FRP reinforcing bars showed the highest bond strength than that of the others due to the higher relative rib area.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.4
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• pp.37-45
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• 2022

In this paper, a multi agent-multi task assignment problem, which is a representative problem of combinatorial optimization, is presented. The objective of the problem is to determine the coordinated agent-task assignment that maximizes the sum of the achievement rates of each task. The achievement rate is represented as a concave down increasing function according to the number of agents assigned to the task. The problem is expressed as an NP-hard problem with a non-linear objective function. In this paper, to solve the assignment problem, we propose a hybrid cross-entropy algorithm as an effective and efficient solution methodology. In fact, the general cross-entropy algorithm might have drawbacks (e.g., slow update of parameters and premature convergence) according to problem situations. Compared to the general cross-entropy algorithm, the proposed method is designed to be less likely to have the two drawbacks. We show that the performances of the proposed methods are better than those of the general cross-entropy algorithm through numerical experiments.