• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2644-2657
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• 2018

To utilize the energy of sensor nodes efficiently and extend the network lifetime maximally is one of the primary goals in wireless sensor networks (WSNs). Thus, designing an energy-efficient protocol to optimize the determination of cluster heads (CHs) in WSNs has become increasingly important. In this paper, we propose a novel energy-efficient protocol based on an improved Grey Wolf Optimizer (GWO), which we refer to as Fitness value based Improved GWO (FIGWO). It considers a fitness value to improve the finding of the optimal solution in GWO, which ensures a better distribution of CHs and a more balanced cluster structure. According to the distance to the CHs and the BS, sensor nodes' transmission distance are recalculated to reduce the energy consumption. Simulation results demonstrate that the proposed approach can prolong the stability period of the network in comparison to other algorithms, namely by 31.5% in comparison to SEP, and even by 57.8% when compared with LEACH protocol. The results also show that the proposed protocol performs well over the above comparative protocols in terms of energy consumption and network throughput.

• Journal of the Korean Professional Engineers Association
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• v.38 no.1
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• pp.35-43
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• 2005

What are main contents of Balanced National Development Five Years Plan? We will study for contents and policies of the plan's six themes. Six themes of the plan are the drive strategy, the rearing of the worldwide progressive cluster, the local promotion in the strategic industry, the formation of the square national circulation road network, the consolidation of the metropolitan area and the independent drop-out region, and the fund and raising plan. And especially, we will study the details of the national land-structure network formation.

• Journal of Korea Multimedia Society
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• v.21 no.6
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• pp.667-677
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• 2018

Since sensor networks consist of sensor nodes with limited energy resources, so efficient energy use of sensor nodes is very important in the design of sensor networks. Sensor nodes consume a lot of energy for data transmission. Clustering technique is used to efficiently use energy in data transmission. Recently, mobile sink techniques have been proposed to reduce the energy load concentrated on the cluster header near a sink node. The CMS(Cluster-based Mobile sink) technique minimizes the generation of control messages by creating a data transmission path while creating clusters, and supports the inter-cluster one-hop transmission. But, there is a case where there is no connectivity between neighbor clusters, it causes a problem of having a long hop data transmission path regardless of local distance. In this paper, we propose a SCBC(Strong connection balancing cluster) to support the path of the minimum number of hops. The proposed scheme minimizes the number of hops in the data transmission path and supports efficient use of energy in the cluster header. This also minimizes a number of hops in data transmission paths even when the sink moves and establishes a new path, and it supports the effect of extending the life cycle of the entire sensor network.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.2
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• pp.40-51
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• 2021

The purpose of this study is to diagnose urban spatial structures using spatial modeling techniques for balanced urban development as part of sustainable urban growth management. Since urban spatial structure is an interaction of various activities, it is necessary to interpret the analysis results in conjunction with the analysis of changes in spatial structural elements. In this study, population and transportation were approached for research purposes. Population data were applied to the Getis-Ord G_i^* method, a spatial statistical technique, to analyze the concentration-decreasing region of the population. Traffic data analyzed the trend of centrality change by applying commuting traffic O-D data to Social Network Analysis techniques. The analysis showed that urban imbalance was growing, and the centrality of transportation was changing. The results of the analysis of spatial structure elements could be interpreted by linking the results of each factor to each neighborhood unit, predicting changes in urban spatial structure and suggesting directions for sustainable urban growth management.These results could also be used as a decision-making tool for various urban growth management policies introduced to cope with rapid urban development and uncontrollable development in many cities around the world.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.277-284
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• 2007

The routing algorithm many used in the wireless sensor network features the clustering method to reduce the amount of data transmission from the energy efficiency perspective. However, the clustering method results in high energy consumption at the cluster head node. Dynamic clustering is a method used to resolve such a problem by distributing energy consumption through the re-selection of the cluster head node. Still, dynamic clustering modifies the cluster structure every time the cluster head node is re-selected, which causes energy consumption. In other words, the dynamic clustering approaches examined in previous studies involve the repetitive processes of cluster head node selection. This consumes a high amount of energy during the set-up process of cluster generation. In order to resolve the energy consumption problem associated with the repetitive set-up, this paper proposes the Round-Robin Cluster Header (RRCH) method that fixes the cluster and selects the head node in a round-robin method The RRCH approach is an energy-efficient method that realizes consistent and balanced energy consumption in each node of a generated cluster to prevent repetitious set-up processes as in the LEACH method. The propriety of the proposed method is substantiated with a simulation experiment.

• Korean Journal of Social Welfare Studies
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• no.36
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• pp.81-101
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• 2008

The purpose of this study is to analyze characteristics of welfare level for the persons with disabilities in Korean local governments. The study adopted multidimensional scaling and cluster analysis. Based on prior studies and comparative importance research, three indicators were extracted from the welfare circumstance index for the disabled. They are the ratio of the registered disabled population, the ratio of the disabled household in poor households, the ratio of dependence on public finance. Also, nine dimensions and twenty seven indicators were extracted from the welfare level index. The dimensions are as follows : Education, income & economic activities support, welfare services infra-structure, health & welfare service support, movement convenience & safety, rights protection, culture, leisure & information accessibility, welfare administration & budget for the disabled. The findings from the welfare circumstance index show that local governments are divided into three groups and all indicators are statistically significant. On the other hand, the findings from the welfare level index, show that local governments are divided into four groups and five indicators are statistically significant. Based on these findings, the study proposes improvement in the disabled welfare level, and balanced development of local governments.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.3
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• pp.232-242
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• 2021

The aim of this article is to examine the role of Gyeonggi Province in the industrial development in the Republic of Korea by taking a case study of the program of the national innovative cluster (NIC). In such program which has been for the purpose of the regional industrial development for non-Seoul metropolitan regions (N-SMRs) since 2018, the total firms' transactions were highly focused upon Gyeonggi Province and other Seoul metropolitan regions (SMRs). Especially, firms' transactions in 5 clusters of the total 14 clusters concentrated on Gyeonggi Province. Within this context, the future direction of this policy program for the regional industrial development and the national balanced development is more focused upon a win-win strategy between the SMR and N-SMRs rather than the dichotomy between them.

• Journal of Power Electronics
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• v.14 no.5
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• pp.946-956
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• 2014

Cascaded H-Bridge (CHB) converters can be directly connected to medium-voltage grids without using transformers and they possess the advantages of large capacity and low harmonics. They are significant tools for providing grid connections in large-capacity renewable energy systems. However, the reliability of a grid-connected CHB converter can be seriously influenced by the number of power switching devices that exist in the structure. This paper proposes a fault-tolerant control strategy based on double zero-sequence voltage injection and DC voltage optimization to improve the reliability of star-connected CHB converters after one or more power units have been bypassed. By injecting double zero-sequence voltages into each phase cluster, the DC voltages of the healthy units can be rapidly balanced after the faulty units are bypassed. In addition, optimizing the DC voltage increases the number of faulty units that can be tolerated and improves the reliability of the converter. Simulations and experimental results are shown for a seven-level three-phase CHB converter to validate the efficiency and feasibility of this strategy.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.2
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• pp.16-27
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• 2011

Embryo is a very early stage of the development of multicellular organism such as animals and plants. It is an important research target for studying ontogeny because the fundamental body system of multicellular organism is determined during an embryo state. Researchers in the developmental biology have a large volume of embryo image databases for studying embryos and they frequently search for an embryo image efficiently from those databases. Thus, it is crucial to organize databases for their efficient search. Hierarchical clustering methods have been widely used for database organization. However, most of previous algorithms tend to produce a highly skewed tree as a result of clustering because they do not simultaneously consider both the size of a cluster and the number of objects within the cluster. The skewed tree requires much time to be traversed in users' search process. In this paper, we propose a method that effectively organizes a large volume of embryo image data in a balanced tree structure. We first represent embryo image data as a similarity-based graph. Next, we identify clusters by performing a graph partitioning algorithm repeatedly. We check constantly the size of a cluster and the number of objects, and partition clusters whose size is too large or whose number of objects is too high, which prevents clusters from growing too large or having too many objects. We show the superiority of the proposed method by extensive experiments. Moreover, we implement the visualization tool to help users quickly and easily navigate the embryo image database.

• The Research Journal of the Costume Culture
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• v.1 no.2
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• pp.159-179
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• 1993

The purpose of this study is to collect data for he improvement of the accuracy of upper garments construction of the old whose bodies have been changed due to their age. In this study the body measurements with 61 items were taken from 226 men(aged fro m 60 to 80) living in Seoul by the R. Martin's method in 1992. The data were calculate by computer and analyzed by the multivariate method, especially factor and cluster analysis. The results of the study were as follows; 1. The average stature of elderly males was 163.6cm, chest circumference 91.6cm, waist circumference 9\\85.5cm. hip circumference 92.8cm, neck circumference 37cm, arm length 55.4 cm, back length 42.6cm, shoulder breadth 42.9cm and the Roher's Index 1.39, which was a standard body shape. 2. The items of factor analysis were explained to seven, namely, the degree of fatness of the upper body, the size of the frame of body, the length of the upper body, the degree of curve of the front body, the size of shoulder, the shape of the back, and the slope of shoulder. 3. The body types of subjects were classified into four types. The majority was type 4, which was 67% of subjects and considered as balanced body type. The distinctive features of those types are as follows; Type 1. The subjects of this type had a slight skeletal structure and were the thinnest of all the subjects with thin and forward-bent arm. Type 2. The subjects of this type were the tallest of all the subjects. they had the straightest side of body and a well-developed upper arm. The thigh length of this type was longer than the length of trunk. Type. 3. The subjects of this type was only one, so ti could be excluded. Type 4. The subjects of this type had a long trunk, well-developed shoulder, and a crook in their neck and back. The arm length and thigh of this type were short and those circumferences were thick. Type 5. The subjects of this type were the shortest of all, but had the highest degree of fatness in the waist and abdominal. They had well-developed front muscles of body and projected hip.