• Journal of IKEEE
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• v.17 no.3
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• pp.371-377
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• 2013

This thesis propose an efficient parallel structure method for implementing a FAST and BRIEF algorithm based Augmented Reality. SURF algorithm that is well known in the object recognition algorithms is robust in object recognition. However, there is a disadvantage for real time operation because, SURF implementation requires a lot of computation. Therefore, we used a FAST and BRIEF algorithm for object recognition, and we improved Conventional Parallel Structure based on OpenMP Library. As a result, it achieves a 70%~100% improvement in execution time on the embedded system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1706-1711
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• 2013

This paper presents the filter of a resonator comprising a shorted open gap ring(SOGR) and interdigital lines. The proposed filter has the ultra wideband characteristic operating from 3 GHz to 10.5 GHz. In order to achieve the remarkable improvement in the size-reduction of the overall filter structure, only one cell of the SOGR with the inter-digital lines is adopted. It is shown that this filter has the size of $18mm{\times}15mm$ using a metamaterial, the fractional bandwidth over 100%, the insertion loss much less than 1dB, an acceptable return loss performance in the results.

• Journal of Magnetics
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• v.18 no.2
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• pp.130-134
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• 2013

Most electrical machines like motor, generator and transformer are symmetric in terms of magnetic field distribution and mechanical structure. In order to analyze these problems effectively, many coupling techniques have been introduced. This paper deals with a coupling scheme for open boundary problem of symmetric and periodic structure. It couples an analytical solution of Fourier series expansion with the standard finite element method. The analytical solution is derived for the magnetic field in the outside of the boundary, and the finite element method is for the magnetic field in the inside with source current and magnetic materials. The main advantage of the proposed method is that it retains sparsity and symmetry of system matrix like the standard FEM and it can also be easily applied to symmetric and periodic problems. Also, unknowns of finite elements at the boundary are coupled with Fourier series coefficients. The boundary conditions are used to derive a coupled system equation expressed in matrix form. The proposed algorithm is validated using a test model of a bush bar for the power supply. And the each result is compared with analytical solution respectively.

• Water Engineering Research
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• v.6 no.3
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• pp.101-112
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• 2005

This paper presents the state of the art of the CFD applications to vegetated open-channel flows. First, important aspects of the physics of vegetated flows found through the laboratory experiments are briefly reviewed. Then, previous CFD applications to one-dimensional vertical structure, partly-vegetated flows, compound open-channel flows with floodplain vegetation, and fully three-dimensional numerical simulations are reviewed. Finally, topics for further researches such as relationship between the resistance and flexural rigidity, additional drag due to foliages, and melting the experience of CFD with the depth-averaged modeling, are suggested.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.2
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• pp.250-253
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• 2011

In this paper, we study characterizations of fuzzy weakly r-M continuous function on r-minimal structures in terms of generalized fuzzy r-minimal open sets.

• Knowledge Management Research
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• v.18 no.4
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• pp.287-306
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• 2017

This research focus on the effect of developers' participation structure in knowledge creation and knowledge sharing activities in open source software development projects. Based on preferential selection theory, hypotheses of relationship between a developers' concentration of knowledge creation/sharing activities and collaboration performance was derived. To verify the hypotheses, we use the Gini coefficient in the commit contribution of the developers (knowledge creation) and the centralization index in the repository issue network (knowledge sharing network). Using social network analysis, this paper calculates centralization index from developers in the issue boards in each repository based on data from 837 repositories in GitHub, a leading open source software development platform. As a result, instead of all developers creating and sharing knowledge equally, only a few of developers creating and sharing knowledge intensively further improve the performance of the open collaboration. In other words, a few developers predominantly providing commit and actively responding to issues raised from other developers enhance the project performance. The results of this study are expected to be used by developers who manage open source software project as a governance strategy, which could improve the performance of open collaboration.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.6
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• pp.37-43
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• 2013

In this paper, an UWB (Ultra Wide Band) band-pass filter with open stubs using SIR (Stepped Impedance Resonator) structure is presented. The proposed band pass filter (BPF) has SIR structure instead of open stubs for UWB application with low insertion loss. The bandwidth of the proposed BPF is 103 % at the center frequency of 5.8GHz and the insertion and return losses are 0.17dB and 13.1dB, respectively. Also, the entire size of the proposed band-pass filter is $21.6{\times}17.8mm^2$.

• Journal of information and communication convergence engineering
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• v.14 no.4
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• pp.246-251
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• 2016

In this study, we developed a reduced 94 GHz hybrid ring coupler on a GaAs substrate in order to demonstrate the possibility of the integration of various passive components and MMICs in the millimeter-wave range. To reduce the size of the hybrid ring coupler, we used multiple open stubs on the inside of the ring structure. The chip size of the reduced hybrid ring coupler with multiple open stubs was decreased by 62% compared with the area of the hybrid ring coupler without open stubs. Performance in terms of the loss, isolation, and phase difference characteristics exhibited no significant change after the use of the multiple open stubs on the inside of the ring structure. The reduced hybrid ring coupler showed excellent coupling loss of $3.87{\pm}0.33dB$ and transmission loss of $3.77{\pm}0.72dB$ in the measured frequency range of 90-100 GHz. The isolation and reflection were -48 dB and -32 dB at 94 GHz, respectively. The phase differences between two output ports were $180^{\circ}{\pm}1^{\circ}$ at 94 GHz.

• Korean Journal of Computational Design and Engineering
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• v.2 no.4
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• pp.222-236
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• 1997

Conventional solid or surface modeling systems cannot represent both the complete solid model and the abstract model in a unified framework. Recently, non-manifold modeling systems are proposed to solve this problem. This paper describes FlexDesigner, an open kernel system for modeling non-manifold models. It summarizes the data structure for non-manifold models, system design methodology, system modularization, and the typical characteristics of each module in the system. A data structure based on partial-topological elements is adopted to represent the relationship among topological elements. It is efficient in the usage of memory and has topological completeness compared with other published data structures. It can handle many non-manifold situations such as isolate vertices, dangling edges, dangling faces, a mixed dimensional model, and a cellular model. FlexDesigner is modularized hierarchically and designed by the object-oriented methodology for reusability. FlexDesigner is developed using the C++ and OpenGL on both SGI workstation and IBM PC.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.6
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• pp.95-113
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• 2018

We studied the change of wetland vegetation structure to understand ecological restoration process of wetlands through the field survey of ecological restoration projects in Incheon, Iksan and Busan. We compared the vegetation plan at the time of planted with the results of the vegetation monitoring in 2018, and analyzed the changes in wetland vegetation structure. Based on results, we attempted to understand the restoration process of those wetlands and discuss the management measures for sustainable wetland restoration. As a result, in the Incheon Yeonhee restoration wetland, the number of plant species was increased, from 18 species in 2016 to 29 in 2018. The dominant species, Myriophyllum verticillatum, covered the wetland most and its occupied area was increased. On the other hand, the distribution area of the planted emergent hydrophytes was reduced. The area of open water decreased from 71.7% in 2016 to 48.8% in 2018. In Busan Igidae restoration wetland, the number of plant species was increased, from 6 species in 2014 to 31 in 2018. The dominant species was Myriophyllum verticillatum and its occupied area was increased. The area of floating plant communities that planned has decreased. The open water area decreased from 83.9% in 2014 to 31.8% in 2018. In Iksan Sorasan restoration wetland, the number of plant species was increased, from 13 species in 2016 to 36 in 2018. The dominant species was Phragmites communis Trin. and its occupied area was increased. The other planted species showed a tendency to be decreased by Phragmites communis Trin. and its terrestrialization. The open water area decreased from 86.6% in 2016 to 6.7% in 2018. These results suggest that wetlands should be managed by considering the change of vegetation structure and open water areas based on the following succession process, because it affects the habitat suitability of wetland organisms and biodiversity as well. Thus, the continuous monitoring for the ecological structure of restored wetland is important, and it could be possible step to develop sustainable wetland ecological restoration model.