• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.314-323
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• 2002

The routing protocols designed for wired networks can hardly be used for mobile ad-hoc networks due to limited bandwidth of wireless transmission and unpredictable topological change. Recently, several routing protocols for mobile ad-hoc networks have been Proposed. However, when theme protocols are applied to support real time services like multimedia transmission, they still have problems in ad-hoc networks, where the topology changes drastically. In this paper, we propose a new route selection algorithm which selects the most reliable route that is impervious to route failures by topological changes by mobile hoots. For reliable route selection, the concept of virtual zone (stable zone and caution zone) is proposed. The zone is located in a mobile node'transmission range and determined by mobile node's mobility information received by Global Positioning System (GPS). The proposed algorithm is applied to the route discovery procedure of the existing on-demand routing protocol, AODV, and evaluated by simulation in various traffic conditions and mobility patterns.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.224-232
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• 2002

The routing protocols designed for wired networks can hardly be used for mobile ad-hoc networks due to limited bandwidth of wireless transmission and unpredictable topological change. Recently, several routing protocols for mobile ad-hoc networks have been proposed. However, when these protocols are applied to support real time services like multimedia transmission, they still have problems in ad-hoe networks, where the topology changes drastically. In this paper, we propose a new route selection algorithm which selects the most reliable rouse that is impervious to route failures by topological changes by mobile hosts. For reliable route selection, the concept of virtual zone (stable lone and caution zone) is proposed. The lone is located in a mobile node's transmission range and determined by mobile node's mobility information received by Global Positioning System (GPS). The proposed algorithm is applied to the route discovery procedure of the existing on-demand routing protocol, AODV, and evaluated by simulation in various traffic conditions and mobility patterns.

• Journal of architectural history
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• v.17 no.6
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• pp.7-27
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• 2008

The primary object of this study lies in reilluminating the meaning of the Baroque, through studying arts and architecture by means of the features of Baroque aesthetics suggested by Deleuze in his writing 'Le Pli' on the basis of Leibniz's 'Pli' concept. Through this study we can see the following. In the first place, the six features - pli, separation between the inner and the exterior, highs and lows, unfolding, texture and paradigm presented as the features of Baroque aesthetics - have to be understood not as being independent features but as those derived from a series of continuous process of folding and unfolding. In the second place, Deleuze's thinking ranging from the 'Pli' of the Baroque to the paradigm derived on the ground of Leibniz thinking is a dynamic world of folding and unfolding, ultimately seeking unity through the topological changes and succession repeating deterritorization and reterritorization. In the third place, most architectural trends claiming 'Fold Architect' or the 'Pli' of Deleuze as their architectural philosophy are committing errors of mass-producing standardized designs by confining the meaning of Deleuze's 'Pli' concept into a simple reproduction of plied superficial things. With this finding in mind, the concept of folding and unfolding examined through reilluminating the Baroque Architecture where the 'Pli' concept is embodied, suggests to us that the problems of contemporary architecture should be rightened, and shows us that it can become an architectural philosophy which can be concretely realized in architecture.

• Korean Institute of Interior Design Journal
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• no.16
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• pp.22-28
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• 1998

The purpose of this study is to analyze the architectural space of modern and contemporary architecture which has been changed by the aesthetic cognition on space. The intention of considering architectural space aesthetically is to convert the viewpoint of seeing space as simple physical structure into different viewpoint of regarding 'space' as 'cultural place' However this does not means to apply aesthetic theory to architectural space. The aesthetic cognition on space is one of the main subjects of the expression of art from ancient to today however the appearance of space concept as architectural aesthetics accelerated by G. Semper theory after the latter half of 19th century. On the standpoint of perpetuity in architecture the aesthetics of scientific rationalism in modernism based on the reasonable thinking regards the variety of inherent characteristic in architectural space as 'Transferential Space'. On the other hand, in regarding to architectural trend, the nature in architectural space has been considered as 'Existential Space' starting from the conscious construction of environments to help human existence in the existentialism. The Conclusion logic of follows as belows; first, the concept of space structure in architecture has been exchanged from Enclosed Space to Topological Space. Second, the concept of architectural space has been changed and developed to the Deterministic, Profound, Dissipative, and Recognizable Space according to the change of expression in architecture.

• Journal of computational fluids engineering
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• v.18 no.4
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• pp.17-24
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• 2013

In this study, we consider the characteristics of channel flow in the presence of an infinite streamwise array of equispaced identical rotating circular cylinders. This flow configuration can be regarded as a model representing a micro channel or an internal heat exchanger with cylindrical vortex generators. A numerical parametric study has been carried out by varying Reynolds number based on the bulk mean velocity and the cylinder diameter, and the gap between the cylinders and the channel wall for some selected angular speeds. An immersed boundary method was employed to facilitate implementing the cylinders on a Cartesian grid system. No-slip condition is employed at all solid boundaries including the cylinders, and the flow is assumed to be periodic in the streamwise direction. The presence of the rotating circular cylinders arranged periodically in the streamwise direction causes a significant topological change of the flow, leading to increase of mean friction on the channel walls. More quantitative results as well as qualitative physical explanations are presented to justify the effectiveness of rotating cylinders to modify flow topology, which might be used to enhance heat transfer on the channel walls.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.1
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• pp.28-33
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• 1985

A modified directed product graph (DPGm) is proposed for the numerator of the network functions of a given non-reciprocal network. By this, the numerator can be obtained topologically and systematically without the sign rule of the Mason's formula and without the change of topological prcperties of the net work throughout the processes. And by taking the subgraph of the DPGm for each vertex, a number of cancelling terms can be removed mechanically from the DPGm beforehand and there(ore the above can be acquired more simply and rapidly.

• Journal of Information Technology Applications and Management
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• v.11 no.2
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• pp.205-214
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• 2004

Internet evolves into the huge network with new nodes inserted or deleted depending on specific situations. A new model of network topology is needed in order to analyze time-varying Internet more realistically and effectively. In this study the non-monotony models are proposed which can describe topological changes of Internet such as node insertion and deletion, and can be used for predicting its future topology. Simulation is performed to analyze the topology generated by our model. Simulation results show that our proposed model conform the power law of realistic Internet better than conventional ones. The non-monotony model can be utilized for designing Internet protocols and networks with better security.

• Journal of the Korean Mathematical Society
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• v.54 no.2
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• pp.399-415
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• 2017

Given a topological space X and a non-negative integer k, we study the self-homotopy equivalences of X that do not change maps from X to n-sphere $S^n$ homotopically by the composition for all $n{\geq}k$. We denote by ${\varepsilon}^{\sharp}_k(X)$ the set of all homotopy classes of such self-homotopy equivalences. This set is a dual concept of ${\varepsilon}^{\sharp}_k(X)$, which has been studied by several authors. We prove that if X is a finite CW complex, there are at most a finite number of distinguishing homotopy classes ${\varepsilon}^{\sharp}_k(X)$, whereas ${\varepsilon}^{\sharp}_k(X)$ may not be finite. Moreover, we obtain concrete computations of ${\varepsilon}^{\sharp}_k(X)$ to show that the cardinal of ${\varepsilon}^{\sharp}_k(X)$ is finite when X is either a Moore space or co-Moore space by using the self-closeness numbers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.182-189
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• 1996

The focus of this study is on the problem of the design of structure of undetermined topology. This problem has been regarded as being the most challenging of structural optimization problems, because of the difficulty of allowing topology to change. Conventional approaches break down when element sizes approach to zero, due to stiffness matrix singularity. In this study, a novel nonlinear Programming formulation of the topology Problem is developed and examined. Its main feature is the ability to account for topology variation through zero element sizes. Stiffness matrix singularity is avoided by embedding the equilibrium equations as equality constraints in the optimization problem. Although the formulation is general, two dimensional plane elasticity examples are presented. The design problem is to find minimum weight of a plane structure of fixed geometry but variable topology, subject to constraints on stress and displacement. Variables are thicknesses of finite elements, and are permitted to assume zero sizes. The examples demonstrate that the formulation is effective for finding at least a locally minimal weight.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.784-788
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• 2004

A visualization study of shock formation of the supersonic jet nozzle using a Shadowgraph Method (SM) was carried out to investigate the effect of the longitudinal variation of coaxial pipe end tip position inside the supersonic nozzle. The experiment was performed for the Mach number range from 1.1 to 1.2 at nozzle exit. The well known shock cell structure was shown with the pipe end located deep inside the nozzle for the studied Mach number. With the pipe end approaches nozzle exit, it was found that the shock cell structure disappeared and turned into complex formation. In order to understand the mechanism of the shock structural change, computational simulation was carried out using the Navier-Stokes solver, FLUENT. Topological sketch was added with an aid of the visualization and the numerical simulation.