• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.387-387
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• 2006

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.4 s.235
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• pp.570-577
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• 2005

In this study a complete 3D surface reconstruction method is proposed based on the concept that the vertices of surface model can be completely matched to the unstructured point cloud. In order to generate the initial mesh model from the point cloud, the mesh subdivision of bounding box and shrink-wrapping algorithm are introduced. The control mesh model for well representing the topology of point cloud is derived from the initial mesh model by using the mesh simplification technique based on the original QEM algorithm, and the parametric surface model for approximately representing the geometry of point cloud is derived by applying the local subdivision surface fitting scheme on the control mesh model. And, to reconstruct the complete matching surface model, the insertion of isolated points on the parametric surface model and the mesh optimization are carried out Especially, the fast 3D surface reconstruction is realized by introducing the voxel-based nearest-point search algorithm, and the simulation results reveal the availability of the proposed surface reconstruction method.

• International Journal of CAD/CAM
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• v.4 no.1
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• pp.11-17
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• 2004

In this paper, an exponential bound of the distance between a Loop subdivision surface and its control mesh is derived based on the topological structure of the control mesh. The exponential bound is independent of the process of recursive subdivisions and can be evaluated without subdividing the control mesh actually. Using the exponential bound, we can predict the depth of recursion within a user-specified tolerance as well as the error bound after n steps of subdivision. The error-estimating approach can be used in many engineering applications such as surface/surface intersection, mesh generation, NC machining, surface rendering and the like.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3470-3493
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• 2019

IEEE 802.11s-based infrastructure Wireless Mesh Networks (iWMNs) are envisaged as a promising solution to provide ubiquitous wireless Internet access. The limited network capacity is a problem mainly caused by the medium contention between mesh users and the mesh access points (MAPs), which gets worst when the mesh clients employ the Transmission Control Protocol (TCP). To mitigate this problem, we use wireless network coding (WNC) in the MAPs. The aim of this proposal is to take advantage of the network topology around the MAPs, to alleviate the contention and maximize the use of the network capacity. We evaluate WNC when is used in MAPs. We model the formation of coding opportunities and, using computer simulations, we evaluate the formation of such coding opportunities. The results show that as the users density grows, the coding opportunities increase up to 70%; however, at the same time, the coding delay increments significantly. In order to reduce such delay, we propose to adaptively adjust the time that a packet can wait to catch a coding opportunity in an MAP. We assess the performance of moving-average estimation methods to forecast this adaptive sojourn time. We show that using moving-average estimation methods can significantly decrease the coding delay since they consider the traffic density conditions.

• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.253-261
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• 2004

A simple and effective filtering method to control the member size of an optimized structure is proposed for topology optimization. In the present approach, the original objective sensitivities are replaced with their relative values evaluated within a filtering area. By adjusting the size of the filtering area, the member size of an optimized structure or the level of its topological complexity can be controlled even within a given finite element mesh. In contrast to the checkerboard-free filter, the present filter focuses on high-frequency components of the sensitivities. Since the present filtering method does not add a penalty term to the objective function nor require additional constraints, it is not only efficient but also simple to implement. Mean compliance minimization and eigenfrequency maximization problems are considered to verify the effectiveness of the present approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.572-580
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• 2010

The Wireless Mesh Network uses a wireless communication technology with transmission rates simular to a cable which is used as a backbone networks. The topology structure is in a Mesh form which resembles an Ad-hoc networks. However, a metric is needed in order to set the channel access control method to operate intentions and interior motions are different. In this document, an efficient channel for delivering datas to improve access controls to a wireless mesh networks. The improved performance of the proposed plan is for a hidden and exposed mesh client through an exclusive channels to perform a proposed and analyzed methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.872-882
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• 2006

The Wireless Mesh Network uses a wireless communication technology with transmission rates similar to that of a cable, which is used as a backbone network. The topology structure is in a Mesh form which resembles an Ad-hoc network, however a metric is needed in order to set the channel and channel methods since the operation intentions and interior motions are different. This thesis proposes a metric(ETR : Expected Transmission Rate) that sets the channel with physical link performance and multi hop transmission capabilities. This metric will also be based on multi channel creation methods and Hop-by-hop routing techniques for an effective multi hop transmission with no loops.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.11
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• pp.984-990
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• 2016

In wireless mesh sensor networks (WMSNs), sensor nodes are connected in the form of a mesh topology and transfer sensor data by multi-hop routing. A data aggregation method for WMSNs is required to minimize the number of routing hops and the energy consumption of each node with limited battery power. This paper presents a shortest path data aggregation method for WMSNs. The proposed method utilizes a simple hash function based on shuffled row major indexing for addressing sensor nodes. This allows sensor data to be aggregated without complex routing tables and calculation for deciding the next hop. The proposed data aggregation algorithms work in a fractal fashion with different mesh sizes. The method repeatedly performs gathering and moves sensor data to sink nodes in higher-level clusters. The proposed method was implemented and simulations were performed to confirm the accuracy of the proposed algorithms.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.8
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• pp.393-398
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• 2005

In interconnection networks, a Hamiltonian path has been utilized in many applications such as the implementation of linear array and multicasting. In this paper, we consider the Hamiltonian properties of mesh networks which are used as the topology of parallel machines. If a network is strongly Hamiltonian laceable, the network has the longest path joining arbitrary two nodes. We show that a two-dimensional mesh M(m, n) is strongly Hamiltonian laceabie, if $m{\geq}4,\;n{\geq}4(m{\geq}3,\;n{\geq}3\;respectively)$, and the number of nodes is even(odd respectively). A mesh is a spanning subgraph of many interconnection networks such as tori, hypercubes, k-ary n-cubes, and recursive circulants. Thus, our result can be applied to discover the fault-hamiltonicity of such networks.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.382-386
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• 2004

This paper presents an algorithm for the triangular mesh intersection problem. The key aspect of the proposed algorithm is to reduce the number of triangle pairs to be checked for intersection. To this end, it employs two different approaches, the Y-group approach and the space partitioning approach. Even though both approaches have the same objective of reducing the number of triangular-triangular intersection (TTI) pairs, their inherent characteristics are quite different. While the V-group approach works by topology (reduces TTI pairs by guaranteeing no intersection among adjacent triangles), the space partitioning approach works by geometry (reduces TTI pairs by guaranteeing no intersection among distant triangles). The complementary nature of the two approaches brings substantial improvement in reducing the number TTI pairs.