• Journal of Korea Multimedia Society
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• v.24 no.6
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• pp.789-795
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• 2021

In order to provide useful Internet of Things (IoT) services, the locations of IoT devices should be well managed. However, frequent location updates of lots of IoT devices result in signaling overhead in networks. To solve this problem, this paper utilizes the opportunistic fog node (OFN) which is opportunistically available according to the mobility to perform the location updates as a representative of IoT devices. Therefore, the location updates through OFN can reduce the signaling loads of networks. To show the performance of the proposed scheme, we develop an analytic model for the opportunistic location update offloading probability that the location update can be offloaded to OFN from the IoT device. Then, the extensive simulation results are given to validate the analytic model and to assess the performance of the proposed scheme in terms of the opportunistic location update offloading probability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.3
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• pp.133-138
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• 2016

Objectives: To assess the association between muscle invasion by oral squamous cell carcinoma of the posterior mandibular alveolar ridge and cervical lymph node metastasis on the basis of preoperative magnetic resonance imaging (MRI). Materials and Methods: Twenty-six patients with oral squamous cell carcinoma of the posterior mandibular alveolar ridge were evaluated by MRI. The associations between cervical lymph node metastasis and independent factors evaluated by MRI were analyzed. Overall survival was also analyzed in this manner. Representative biopsy specimens were stained with anti-podoplanin and anti-CD34 antibodies. Results: Mylohyoid muscle invasion was associated with cervical lymph node metastasis. A combinational factor of mylohyoid and/or buccinator muscle invasion was also associated with cervical lymph node metastasis. Cervical lymph node metastasis and masticator space invasion had a negative effect on overall survival. No lymphatic vessels were identified near the tumor invasion front within the mandible. In contrast, lymphatic vessels were identified near the front of tumor invasion in the muscles. Conclusion: This study demonstrates an association between muscular invasion by oral squamous cell carcinoma of the posterior mandibular alveolar ridge and cervical lymph node metastasis.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.442-446
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• 2010

In this paper we propose an indexing method supporting the browsing scheme for effective image search on large photo database. The proposed method is based on M-tree, a representative indexing scheme on matrix space. While M-tree focuses on the searching efficiency by pruning, it did not consider browsing efficiency directly. This paper proposes node selection method, node splitting method and node splitting conditions for browsing efficiency. According to test results, node cohesion and clustering precision improved 1.5 and twice the original respectively and searching speed also increased twice the original speed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.3
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• pp.145-151
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• 2012

Objectives: Angiogenesis and lymphangiogenesis are correlated with tumor growth and lymph node metastasis in cases of oral squamous cell carcinoma (OSCC). Endoglin is one of the representative vascular endothelial cell markers. Podoplanin is also a representative marker used in order to detect lymphatic endothelial cells. The aim of this study was to determine the correlation between the expression of endoglin/podoplanin and clinical variables associated with OSCC progression. Materials and Methods: Paraffin embedded tissue specimens from 21 patients diagnosed with OSCC were used in this study. Ten patients were diagnosed with early clinical stage (I or II) and 11 patients with advanced clinical stage (III or IV) OSCC. Five patients had positive lymph node involvement. Primary antibodies for endoglin and podoplanin were used to perform the immunohistochemical detection of the vascular and lymphatic endothelial cells. The expression of endoglin and podoplanin was examined by an image analysis program in the three most highly expressed regions of each specimen. Results: The average endoglin expression was observed to be $1.691{\pm}0.920$ in the advanced stage (III, IV) specimens and $0.797{\pm}0.583$ in the early stage (I, II) specimens (P=0.020). The average expression of podoplanin was $0.286{\pm}0.228$ in the advance stage (III, IV) specimens and $0.374{\pm}0.157$ in the early stage (I, II) specimens (P>0.05). There was no statistically significant difference in the expression of endoglin and podoplanin, regardless of whether or not the lymph node was positive. Conclusion: The expression of endoglin was significantly higher in the advanced stage specimens than that in the early stage specimens. Therefore, we concluded that endoglin is a useful molecular marker for use in the evaluation of the progression of OSCC.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.91-105
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• 2010

A wireless sensor network communication technique has been broadly studied with continuous advances in ubiquitous computing environment. Especially, because the resource of the sensor node is limited, it is important to reduce the communication energy by using an energy-efficient routing protocol. The existing cluster-based routing protocols have a problem that they cannot select a cluster head efficiently by randomly choosing a head. In addition, because the existing cluster-based routing protocols do not support the large scale of network, they cannot be used for various applications. To solve the above problems, we, in this paper, propose a new cluster-based routing protocol using representative paths. The proposed protocol constructs an efficient cluster with distributed cluster heads by creating representative paths based on hop count. In addition, a new routing protocol supports multi-hop routing for data communication between a cluster member node and a cluster head as well as between cluster heads. Finally, we show that our protocol outperforms LEACH and Multihop-LEACH in terms of reliability and scalability.

• The Journal of Society for e-Business Studies
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• v.26 no.3
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• pp.67-80
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• 2021

The node embedding technique for learning graph representation plays an important role in obtaining good quality results in graph mining. Until now, representative node embedding techniques have been studied for homogeneous graphs, and thus it is difficult to learn knowledge graphs with unique meanings for each edge. To resolve this problem, the conventional Triple2Vec technique builds an embedding model by learning a triple graph having a node pair and an edge of the knowledge graph as one node. However, the Triple2 Vec embedding model has limitations in improving performance because it calculates the relationship between triple nodes as a simple measure. Therefore, this paper proposes a feature extraction technique based on a graph convolutional neural network to improve the Triple2Vec embedding model. The proposed method extracts the neighborliness vector of the triple graph and learns the relationship between neighboring nodes for each node in the triple graph. We proves that the embedding model applying the proposed method is superior to the existing Triple2Vec model through category classification experiments using DBLP, DBpedia, and IMDB datasets.

• ETRI Journal
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• v.27 no.1
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• pp.1-12
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• 2005

We propose a heuristic buffer management scheme that uses both positive and negative acknowledgments to provide scalability and reliability. Under our scheme, most receiver nodes only send negative acknowledgments to their repair nodes to request packet retransmissions while some representative nodes also send positive acknowledgments to indicate which packets can be discarded from the repair node's buffer. Our scheme provides scalability because it significantly reduces the number of feedbacks sent by the receiver nodes. In addition, it provides fast recovery of transmission errors since the packets requested from the receiver nodes are almost always available in their buffers. Our scheme also reduces the number of additional retransmissions from the original sender node or upstream repair nodes. These features satisfy the original goal of treebased protocols since most packet retransmissions are performed within a local group.

• International journal of advanced smart convergence
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• v.3 no.2
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• pp.1-5
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• 2014

Sensor nodes depend on batteries for energy source in Wireless Sensor Networks (WSNs). Low Energy Adaptive Clustering Hierarchy (LEACH) is a representative cluster-based routing protocol designed to ensure energy use efficiency whereas the virtual cluster exchange routing (VCR) information only with its closest node to build a network. In this paper, a protocol scheme was proposed wherein member nodes are designed to compare the currently sensed data with the previously sensed one and to switch to sleep mode when a match is achieved. The design is to help improve the transmission energy efficiency too.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.235-249
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• 2008

On-demand routing protocol in ad hoc network is that establishes a route to a destination node only when it is required by a source node. But, it is necessary to reestablish a new route when an active route breaks down. The reconstruction process establishes another route by flooding messages from the source to the destination, cause not only heavy traffic but also long delays in route discovery. A good method for analyzing performance of protocols is important for deriving better systems. In this paper, we suggest the numerical formulas of a representative on-demand routing protocol AODV, ARMP, and RRAODV to estimate the performance of these routing protocols for analyzing the performance of these protocols. The proposed analytical models are very simple and straightforward. The results of analysis show good agreement with the results of computer simulations.

• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.205-213
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• 2021

The properties of a scale-free network are little known; its node degree following a power-law distribution is among its few known properties. By selecting real-field scale-free networks from a network dataset and comparing them to other networks, such as random and non-scale-free networks, the topology characteristics of scale-free networks are identified. The assortative coefficient is identified as a key metric of a scale-free network. It is also identified that most scale-free networks have negative assortative coefficients. Traditional generation models of scale-free networks are evaluated based on the identified topology characteristics. Most representative models, such as BA and Holme&Kim, are not effective in generating real-field scale-free networks. A link-rewiring method is suggested that can control the assortative coefficient while preserving the node degree sequence. Our analysis reveals that it is possible to effectively reproduce the assortative coefficients of real-field scale-free networks through link-rewiring.