• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.12-19
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• 2020

The clustered heterogeneous wireless sensor network is comprised of sensor nodes and cluster heads, which are hierarchically organized for different objectives. In the network, we should especially take care of managing node resources to enhance network performance based on memory and battery capacity constraints. For instances, if some interesting events occur frequently in the vicinity of particular sensor nodes, those nodes might receive massive amounts of data. Data congestion can happen due to a memory bottleneck or link disconnection at cluster heads because the remaining memory space is filled with those data. In this paper, we utilize drones as mobile sinks to resolve data congestion and model the network, sensor nodes, and cluster heads. We also design a cost function and a congestion indicator to calculate the degree of congestion. Then we propose a data congestion map index and a data congestion mapping scheme to deploy drones at optimal points. Using control variable, we explore the relationship between the degree of congestion and the number of drones to be deployed, as well as the number of drones that must be below a certain degree of congestion and within communication range. Furthermore, we show that our algorithm outperforms previous work by a minimum of 20% in terms of memory overflow.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.321-329
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• 1997

Purpose : It is well known that the risk of lymph nodes metastases to head and neck cancers are influenced by the location and size of the Primary tumor. as well as the degree and types of histological differentiation. However, data on the statistical analyses of lymph node metastases from the head and neck cancers among Korean Population are not available at present. In order to obtain current status of such data, we have analyzed cancer patients at the department of radiation oncology, korea universityhospital for radiation treatment. Materials and Methods : We have evaluated nine-hundred and ninetyseven (997) head and neck cancer Patients who visited to the Department of radiation oncology, between November 1981 to December 1995. After careful physical examinations and CAT scan, Patients were divided into two groups, those with positive lymph node metastases and with negative lymph node metastases. The nodal status were classified according to the TNM system of American Joint Committee on Cancer (AJCC) Besults : Four-hundred and sixteen Patients out of the 997 patients were lymph node positive $(42\%)$ and 581 patients were lymph node negative $(58\%)$ when they were first presented at the department of radiation oncelogy. According to the AJCC classification, the distribution of positive lymph node is as follow: Nl:106 $(25.5\%),\;N2a:100\;(24\%),\;N2b:68\;(16.4\%),\;N2c:69\;(16.6\%),\;3:73\;(15\%).$ respectively. The frequency of lymph node metastases according to the primary sites is as follow : larynx 283 $(28.5\%)$, paranasal sinuses: 182 $(18\%),\;oropharynx:144\;(14.5\%)\;nasopharynx:122(12\%),\;oral\;cavity\;92\;(9\%),\;hypopharynx:71\;(7\%),\;falivary\;gland:58\;(6\%)$ unknown primary:31 $(3\%),\;skin:\;14(2\%)$,. The most frequent Primary site for the positive Iymph node metastases was nasopharynx $(71\%)$ followed by hypopharynx $(69\%),\;oropharynx\;(64\%),\;oral\;cavity\;(39\%)$ The most common histologic type was squamous cell carcinoma (652/997: $65.4\%$). followed by malignant lymphoma $(109/997:11\%)$. Conclusion : Statistical results of lymph node metastases from head and neck cancer at our department were very similar to those obtained from other countries. It is concluded that the location of Primary cancer influences sites of metastases on head and neck, and stage of the primary cancer also influences the development of metastatic lesions. Since the present study is limited on the data collected from one institute. further statistical analyses on Korean cancer Patients are warrented.

• Journal of Gastric Cancer
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• v.5 no.2
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• pp.101-105
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• 2005

Purpose: Some gastric cancer patients in whom the cancer has infiltrated up to the muscularis propria (mp) have a good postoperative course similar to that of early gastric cancer (EGC) patients (this does not match the general classification of gastric cancer). Therefore, we performed a retrospective analysis of 125 patients with mp gastric cancer based on the degree of mp invasion. Materials and Methods: The clinicopathologic features of 125 cases of mp gastric cancer were subdivided according to depth of invasion, and were retrospectively reviewed and compared with the surgical features of 222 patients with gastric cancer invading the submucosa (sm). For each tumor, using the section that showed the greatest extent of invasion, we evaluated the degree of tumor invasion into the mp layer at a magnification of $\times$100. The patients were classified into 2 groups: mp1, the tumor was limited to the first of the 3 mp layers, and mp2, the tumor had expanded beyond the first layer. Results: Patients with mp1 (n=50) had a significantly lower incidence of lymph node metastasis, and a smaller tumor size than patients with mp2 (n=75) (P=0.01 and P=0.029, respectively). The 5-year survival rate of mp1 patients was significantly better than that of mp2 patients ($95.3\%\;vs.\;77.6\%$, P=0.0282), but was similar to that ($91.2\%$) of the 222 sm patients. The 5-year survival rate of mp patients without lymph node metastasis (n=55) was significantly better than that of those with lymph node metastasis (n=70)($93.3\%\;vs.\;78.2\%$, P=0.0192). Patients with mp1 had a significantly higher incidence of lymph node metastasis ($42.5\%\;vs\;23\%$, P=0.006) than patients with sm. Conclusion: There were clear differences in clinical features between the mp1 and the mp2 patients. Subdivision of mp gastric cancer according to the depth of invasion may enable a more precise prognosis and a more pertinent treatment plan for mp patients. In particular, as the clinicopathological findings and surgical outcomes for mp1 patients were akin to those of the sm patients, mp1 patients may require treatment analogous to that administered to patients with sm gastric cancer. (J Korean Gastric Cancer Assoc 2005;5:101-105)

• Tuberculosis and Respiratory Diseases
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• v.38 no.3
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• pp.297-303
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• 1991

Subacute necrotizing lymphadenitis is characterized by cervical lymphadenpathy in young patients and mistaken for malignant disease both clinically and histologically. Microscopically, there is a varying degree of effacement of the lymph node architecture and necrosis with an infiltrate of histiocytic cells and absence of polymorphs. We have experienced 4 cases of cervical lymphadenopathy accompanied by fever. All cases had complete recovery to conservative treatment only. The excised lymph nodes were moderately enlarged and typically showed varying degree of necrotizing lesions, and abundant karyorrhectic debris, scattered fibrin deposits, aggregates of large mononuclear cells, and a paucity of plasma cell and neutrophils. For investigating the etiology and pathogenesis of this lesion, further clinical study and stepwise pathologic and immunologic planning would be valuable.

• ETRI Journal
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• v.46 no.4
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• pp.604-618
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• 2024

In wireless sensor network (WSN) monitoring systems, redundant data from sluggish environmental changes and overlapping sensing ranges can increase the volume of data sent by nodes, degrade the efficiency of information collection, and lead to the death of sensor nodes. To reduce the energy consumption of sensor nodes and prolong the life of WSNs, this study proposes a dual layer intracluster data fusion scheme based on ring buffer. To reduce redundant data and temporary anomalous data while guaranteeing the temporal coherence of data, the source nodes employ a binarized similarity function and sliding quartile detection based on the ring buffer. Based on the improved support degree function of weighted Pearson distance, the cluster head node performs a weighted fusion on the data received from the source nodes. Experimental results reveal that the scheme proposed in this study has clear advantages in three aspects: the number of remaining nodes, residual energy, and the number of packets transmitted. The data fusion of the proposed scheme is confined to the data fusion of the same attribute environment parameters.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.5
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• pp.1333-1353
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• 2012

The robustness of a network is usually measured by error tolerance and attack vulnerability. Significant research effort has been devoted to determining the network design with optimal robustness. However, little attention has been paid to the problem of how to improve the robustness of existing networks. In this paper, we investigate how to optimize attack tolerance and communication efficiency of an existing network under the limited link addition. A survival fitness metric is defined to measure both the attack tolerance and the communication efficiency of the network. We show that network topology reconfiguration optimization with limited link addition (NTRLA) problem is NP-hard. Two approximate solution methods are developed. First, we present a degree-fitness parameter to guide degree-based link addition method. Second, a preferential configuration node-protecting cycle (PCNC) method is developed to do trade-off between network robustness and efficiency. The performance of PCNC method is demonstrated by numerical experiments.

• Journal of the Korean Society for information Management
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• v.32 no.2
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• pp.7-23
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• 2015

While there are several measures for node centralities, such as betweenness and degree, few centrality measures for local centralities in weighted networks have been suggested. This study developed a generalized centrality measure for calculating local centralities in weighted networks. Neighbor centrality, which was suggested in this study, is the generalization of the degree centrality for binary networks and the nearest neighbor centrality for weighted networks with the parameter ${\alpha}$. The characteristics of suggested measure and the proper value of parameter ${\alpha}$ are investigated with 6 real network datasets and the results are reported.

• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.625-634
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• 2003

More than a decade after its initial proposal, deployment of IP Multicast has been limited due to the problem of traffic control in multicast routing, multicast address allocation in global internet, reliable multicast transport techniques etc. Lately, according to increase of multicast application service such as internet broadcast, real time security information service etc., overlay multicast is developed as a new internet multicast technology. In this paper, we describe an overlay multicast protocol and propose fast join mechanism that considers switching of the tree. To find a potential parent, an existing search algorithm descends the tree from the root by one level at a time, and it causes long joining latency. Also, it is try to select the nearest node as a potential parent. However, it can't select the nearest node by the degree limit of the node. As a result, the generated tree has low efficiency. To reduce long joining latency and improve the efficiency of the tree, we propose searching two levels of the tree at a time. This method forwards joining request message to own children node. So, at ordinary times, there is no overhead to keep the tree. But the joining request came, the increasing number of searching messages will reduce a long joining latency. Also searching more nodes will be helpful to construct more efficient trees. In order to evaluate the performance of our fast join mechanism, we measure the metrics such as the search latency and the number of searched node and the number of switching by the number of members and degree limit. The simulation results show that the performance of our mechanism is superior to that of the existing mechanism.

• The Journal of Korean Society for School & Community Health Education
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• v.24 no.1
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• pp.1-15
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• 2023

Objectives: The purpose of this study was to identify the major influencing factors of breast cancer death and to suggest policy measures to promote the health of breast cancer patients. Methods: The method of this study performed statistical analysis by applying weights to 2,300 cases of breast cancer registration statistics in Korea collected in 2018 due to the relatively small number of mortality data compared to survival. Statistical processing of the collected data was analyzed using SPSS 26.0. Results: The epidemiologic characteristics of death in breast cancer patients were 31.8% in those aged 70 years or older, and the mortality rate was 5.25 times higher in patients aged 70 years or older than those aged 39 years or younger. The anatomical site code was 36.4% in C50.4~C50.6, and the mortality rate was 1.82 times higher in C50.4~C50.6 than in C50.0~C50.1. The tumor size was 40.4% and larger than 4cm, and the mortality rate was 4.53 times higher in tumors larger than 4cm than those smaller than 1cm. The degree of differentiation was 13.9% in the poorly differentiated group, and the mortality rate was 4.38 times higher in the poorly differentiated group than in the highly differentiated group. In the hormone receptor test, non-triple negative cases were 59.6%, and the mortality rate was 0.57 times lower in non-triple negative cases than in triple negative cases. As for lymph node involvement, the presence or absence of lymph node involvement was 78.8%, and the mortality rate with lymph node involvement was 1.36 times higher than that without lymph node involvement. The survival period of 13 to 24 months was the highest at 26.5%, and the average survival period was 25.68 months (±14.830). Conclusion: A policy to advance the timing of national health examinations for early detection of breast cancer is necessary. In addition, a bill for the mandatory placement of health educators in medical institutions for patients with special diseases such as breast cancer should be prepared.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.513-514
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• 2006

Recently intradiscal electrothermal therapy is introduced, which is a new and minimally invasive technique fer the treatment of discogenic low back pain. This procedure involves the percutaneous threading of a flexible catheter into the disc under fluoroscopic guidance. The catheter, composed of thermal resistive coil, heats the posterior annulus of the disc, causing contraction of collagen fibers and destruction of afferent nociceptors. This study tries to investigate the effects of the important factors of this procedure such as heat source temperature and heat applying time on the temperature distribution within the intervertebral disc. This study utilized both computer simulation and the experiment for the verification of finite element analysis. FE analysis was carried out with ANSYS v7.0 (ANSYS Inc, USA) using 10,980 number of brick element and 12,551 number of node. The functional spinal units of 5 month old swine were used for the experiment and the temperature was monitored using 10 channel temperature measurement device MV200. Through this study, it was able to analyze the temperature range of inner intervertebral disc by two mechanisms which are known to alleviate pain clinically. The results showed that when the heat source temperature was kept up 80 degree for 1,020 seconds, the temperature of inner annulus reached at 45 degree up to the distance of 15.6mm from heat source, which explains coagulation of inner annulus by heat. When the same heat source was used, the temperature of inner nucleus reached at 60 degree up to the distance of 9mm from heat source, which explains contraction of inner nucleus by heat.