• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.17-20
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• 2008

A clustering scheme for ad hoc networks is aimed at managing a number of mobile devices by utilizing hierarchical structure of the networks. In order to construct and maintain an effective hierarchical structure in ad hoc networks where mobile devices may move at high mobility, the following requirements must be satisfied. The role of each mobile device for the hierarchical structure is adaptive to dynamic change of the topology of the ad hoc networks. The role of each mobile device should thus change autonomously based on the local information. The overhead for management of the hierarchical structure is small. The number of mobile devices in each cluster should thus be almost equivalent. This paper proposes an adaptive multihop clustering scheme for highly mobile ad hoc networks. The results obtained by extensive simulation experiments show that the proposed scheme does not depend on mobility and node degree of mobile devices in the ad hoc network, which satisfy the above requirements.

• ETRI Journal
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• v.31 no.3
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• pp.327-329
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• 2009

In a network, broadcasting is the dissemination of a message from a source node holding a message to all the remaining nodes through a call. This letter proposes a one-to-all broadcasting algorithm in the Petersen-torus network PT(n, n) for the single-link-available and multiple-link-available models. A PT(n, n) is a regular network whose degree is 4 and number of nodes is $10n^2$, where the Petersen graph is set as a basic module, and the basic module is connected in the form of a torus. A broadcasting algorithm is developed using a divide-and-conquer technique, and the time complexity of the proposed algorithm approximates n+4, the diameter of PT(n, n), which is the lower bound of the time complexity of broadcasting.

• Journal of Korea Multimedia Society
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• v.17 no.6
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• pp.725-732
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• 2014

The Pancake graph is node symmetric and useful interconnection network in the field of data sorting algorithm. The Half Pancake graph is a new interconnection network that reduces the degree of the Pancake graph by approximately half and improves the network cost of the Pancake graph. In this paper, we analyze topological properties of the Half Pancake graph $HP_n$. Fist, we prove that $HP_n$ has maximally fault tolerance and recursive scalability. In addition, we show that in $HP_n$, there are isomorphic graphs of low-dimensional $HP_n$. Also, we propose that the Bubblesort $B_n$ can be embedded into Half Pancake $HP_n$ with dilation 5, expansion 1. These results mean that various algorithms designed for the Pancake graph and the Bubble sort graph can be executed on $HP_n$ efficiently.

• International Journal of Advanced Culture Technology
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• v.1 no.2
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• pp.7-12
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• 2013

Mobility management is an important issue in Mobile Ad Hoc Networks (MANETs) because location information of mobile nodes is frequently changed and it aggravates the performance in MANETs drastically. In this paper, we propose a fuzzy logic based mobility management scheme using group quorum system by considering the mobile nodes' locality in order to manage location information of mobile nodes in MANETs efficiently. The proposed scheme selects mobility databases adaptively from group quorum system by considering the degree of locality of a mobile node. The performance of the proposed scheme is evaluated by an analytical model and compared with that of existing mobility management scheme.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.467-470
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• 1998

In this paper, we propose a matrix star graph which improves the network cost of the well-known star grah as an interconnection network. We analyze its characteristics in terms of the network parameters, such as degree, scalability, routing, and diameter. The proposed matrix star graph MS2,n has the half degrees of a star graph S2n with the same number of nodes and is an interconnection network with the properties of node symmetry, maximum fault tolerance, and recursive structure. In network cost, a matrix star graph MS2,n and a star graph S2n are about 3.5n2 and 6n2 respectively which means that the former has a better value by a certain constant than the latter has.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.6
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• pp.331-338
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• 2012

This paper presents a wireless sensor network protocol aimed for artificial structure monitoring. The proposed protocol enables the sensor network to operate at a low duty cycle for reducing power consumption with a high degree of synchronization accuracy. It also enables event-triggered measurement of environmental information with a high sampling rate and the transmission of the measured data with a low latency. The feasibility of the proposed protocol is demonstrated through experiments involving three sensor nodes and a sink node. Though a tunnel health monitoring was considered in the paper, the proposed protocol can be easily adopted in other areas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1194-1200
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• 1991

The FEM is a computer-aided mathematical technique for obtaining approximate solution to the differential equations. The pointwise convergence defines the relationship between the mesh size and the tolerance. This will play an important role in improving quality of finite element approximate solution. In the paper. We evaluate the convergence on a certain unknown point with a 1-irregular mesh refinement and spectral order enrichment. This means that the degree of freedom is minimized within a tolerance.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.998-1007
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• 2018

The advent of Wireless Sensor Networks (WSN) has led to their use in numerous applications. Sensors are autonomous in nature and are constrained by limited resources. Designing an autonomous topology with criteria for economic and energy conservation is considered a major goal in WSN. The proposed honey-hive clustering consumes minimum energy and resources with minimal transmission delay compared to the existing approaches. The honey-hive approach consists of two phases. The first phase is an Intra-Cluster Min-Max Discrepancy (ICMMD) analysis, which is based on the local honey-hive data gathering technique and the second phase is Inter-Cluster Frequency Matching (ICFM), which is based on the global optimal data aggregation. The proposed data aggregation mechanism increases the optimal connectivity range of the sensor node to a considerable degree for inter-cluster and intra-cluster coverage with an improved optimal energy conservation.

• Journal of the military operations research society of Korea
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• v.22 no.2
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• pp.113-125
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• 1996

'Bowl Phenomenon' refers to allocating the work loads to middle stages slightly less than the outer ones in a series production system. Millier and Boling(1966) first discovered that the output rate of a production line were obtained by deliberately unbalancing, like a bowl-shape, under certain circumstances. So far quite a many researches have been studied either theory-oriented or simulation-oriented on this topic. However the papers concerning assemble production line are rather rare possibly due to the system complexity. In this paper, a simulation work on a 6-node assembly line has been conducted with the help of SLAMSYSTEM software. The simulation results have been turned out that 1) the Bowl phenemenon is still valid in the given system, 2) buffer storage between the work stations are critical measure for determining the degree of work-load unbalancing.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.11-17
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• 1999

A three dimensional finite element generation code has been developed attaching simple blocks. Block can be either a quadrature or a cube depending on the dimension of a subject considered. Finite element serendipity basis functions are employed to map elements between the computational domain and the physical domain. Elements can be generated with wser defined progressive ratio for each block. For blocks to be connected properly, a block should have a consistent numbering scheme for vertices, side nodes, edges and surfaces. In addition the edge information such as the number of elements and the progressive ratio for each direction should also be checked for interfaces to have unique node numbers. Having done so, user can add blocks with little worry about the orientation of blocks, Since the present the present code has been written by a Visual Basic language, it can be developed easily for a user interactive manner under a Windows environment.