• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.2
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• pp.7-16
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• 2000

In this paper, IEEE 802.11 MAC layer protocol is modeled by p-persistent CSMA method. And We introduce performance analysis model based on Basic CSMA/CA protocol, CTS/RTS protocol and hidden node effect reflected Basic CSMA/CA Protocol, Which is mathematically assayed by renewal theory. In this throughput, the result shown that Basic CSMA/CA protocol is profitable when the number of active node is smaller, or the length of packet is shorter, and CTS/RTS protocol is lucrative when the number of active node is larger, or the length of packet is longer. Also the result shown that hidden node less affected when the active node has small one, rather than when the active node has larger one.

• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.61-74
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• 1993

A new three-dimensional transition solid element was presented for the automated three-dimensional adaptive h-refinement or the local mesh refinement where the steep stress gradient exists. The proposed transition element was established by adding variable nodes(element nodes) to basic 8-node for an effective connection between the refined region and the coarse region with minimum degrees of freedom possible. To be consistent in accuracy with 8-node solid element with nonconforming modes, this transition element was also improved through the addition of the modified nonconforming modes. Numerical examples show that the performance of the element and the applicability to 3D adaptations are satisfactory.

• Korean Journal of Head & Neck Oncology
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• v.20 no.1
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• pp.13-18
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• 2004

Objectives: Cancer lethality is usually the result of local invasion and metastasis of neoplastic cell from the primary tumor. Because of their ability to degrade extracellular matrix components, matrix metalloproteinases (MMPs) and basic fibroblast growth factor (bFGF) have been implicated in the breakdown of basement membrane and underlying stroma, thereby facilitating tumor growth and invasion. It has been well established that MMPs and bFGF expression correlate with cervical lymph node metastasis, but studies on expression in the metastatic cervical lymph node itself are not enough. We have analyzed matrix metalloproteinases (MMPs) and basic fibroblast growth factor (bFGF) in squamous cell carcinoma of the head and neck and metastatic cervical lymph node, and evaluated their relationship and clinicophathologic significance. Material and Methods: 20 cases of squamous cell carcinoma of the head and neck were entered on the study of immunohistochemical stains for MMP-9 and bFGF in the obtained tissue from primary tumor and metastatic cervical lymph node. We analyzed the relationship between MMP-9, bFGF expression of the primary tumor and metastatic node with age, sex, T-stage, N-stage, histologic grade, pathologic stage and disease free survival. Results: Expression of MMP-9 and bFGF in cancer cell and metastatic lymph node was higher than that in normal cell and lymph node. According to histologic differentiation, expression of MMP-9 of the metastatic cervical lymph node was higher than primary tumor. Considering to other clinicopathologic factor, no statistical significance was seen in MMP-9 and bFGF. Conclusion: We found that expression of MMP-9 is higher in the metastatic lymph node than primary tumor in the poorly differentiated squamous cell carcinoma. But we don't find out the statistical significance in relation between bFGF and clinical factors. So we guess that some different mechanism of MMP-9 and bFGF in Head & Neck squamous cell carcinoma exist. Further studies will be necessary to establish their pathogenesis in the Head and Neck cancer.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.1
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• pp.40-46
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• 2009

This paper presents a self-sustaining system, and an effective method in enhancing overall energy efficiency. The proposed system consists of the two major nodes: a slave node, which contains the environment information (e.g., temperature, humidity, etc.); and a master node, which communicates with the slave nodes, and transmit the slave node's information to users. All slave nodes are under control of the master node. Each slave node uses two power sources: the piezoelectric power generator (PPG); and the continuous wave from the master node. The paper highlights the basic operational principle, each node's specifications, and experimental data for performance verification. The two nodes successfully communicate each other in a range of 3.3m (maximal range), where the user's computer is wired the master node.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.3766-3788
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• 2017

A blockchain is an underlying technology and basic infrastructure of the Bitcoin system. At present, blockchains and their applications are developing rapidly. However, the basic research of blockchain technology is still in the early stages. The efficiency and reliability of blockchain communication is one of the research problems that urgently need to be studied and addressed. Existing algorithms may be less feasible for blockchain-based communication because they only consider a single communication factor (node communication capability or node trust degree) and only focus on a single communication performance parameter(communication time or communication reliability). In this paper, to shorten the validation time of blockchain transactions and improve the reliability of blockchain-based communication, we first establish a multi-link concurrent communication model based on trust degree, and then we propose a novel integrated factor communication tree algorithm (IFT). This algorithm comprehensively considers the node communication link number and the node trust degree and selects several nodes with powerful communication capacity and high trust as the communication sources to improve the concurrency and communication efficiency. Simulation results indicate that the IFT algorithm outperforms existing algorithms. A blockchain communication routing scheme based on the IFT algorithm can increase communication efficiency by ensuring communication reliability.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.560-564
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• 2007

Korea Basic Science Institute(KBSI) has three general electron microscopes including High Voltage Electron Microscope(HVEM) which is the only one in Korea. Observed images through an electron microscope are what they are tilted by each step and saved, offering the more better circumstances for observers, a reconstruction to 3D could be a essential process. In this process, a warping method decreases distortions maximumly of avoided parts of a camera's focus. All these image treatment processes and 3D reconstruction processes are based on an accompaniment of a highly efficient computer, a number of Grid Node Personal computers share this process in a short time and dispose of it. Grid Node Personal computers' purpose is to make an owner can share different each other and various computing resources efficiently and also Grid Node Personal computers is applying to solve problems like a role scheduling needed for a constructing system, a resource management, a security, a capacity measurement, a condition monitoring and so on. Grid Node Personal computers accomplish roles of a highly efficient computer that general individuals felt hard to use, moreover, a image treatment using the warping method becomes a foundation for reconstructing to more closer shape with an real object of observation. Construction of the electron microscope volume 랜더링 system based on Grid Node Personal computer through the warping process can offer more convenient and speedy experiment circumstances to observers, and makes them meet with experiment outcome that is similar to real shapes and is easy to understand.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.2995-3006
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• 1993

An automatic mesh generation scheme has been developed for finite element analysis with two-dimensional, quadrilateral elements. The basic strategies of the method are to transform the analysis domain into loops with key nodes and the loops are recursively subdivided into subloops with the use of best split lines. Finally by using the basic loop operators, the meshes are completed. In this algorithm an eight-node loop operator is proposed, which is useful in the area where the change of element size is large and the splitting criteria for subdividing the loops have also been modified to the existing algorithms. Lines, arcs, and cubic spline curves are used to define the boundaries of analysis domain. Sample meshes for several geometries are presented to demonstrate the robustness of the algorithm.

• Journal of Distribution Science
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• v.3 no.1
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• pp.113-131
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• 2005

This study aims to look into how we Korean ports can improve NODE competitiveness among northern-east region of Asia, and to examine a conceptual as well as practical methodology approach to be applied in terms of cluster. Also many other researches have done to take out the conclusion, which is environmental aspects as economic and logistical one in terms of northern-east region of Asia, basic concept with NODE, and matters concerning seaport from the viewpoint of hub-spoke, etc. Then finally it is suggested that we Korea has to concentrate on seaport, which is equipped with logistics cluster provide into value added logistics, in order to keep and gain the NODE competitiveness in northern-east region of Asia.

• Steel and Composite Structures
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• v.20 no.4
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• pp.869-887
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• 2016

The socket-spigot template supporting system is widely used in engineering applications in China. As a newer type of support structure, there has been growing research interest in its bearing capacity. In this paper, four vertical bearing capacity tests were carried out on the basic mechanical unit frame of a socket-spigot template supporting system. The first goal was to explore the influence of the node semi-rigid degree and the longitudinal spacing of the upright tube on the vertical bearing capacity. The second objective was to analyze the displacement trend and the failure mode during the loading process. This paper presents numerical analysis of the vertical bearing capacity of the unit frames using the finite element software ANSYS. It revealed the relationship between the node semi-rigid degree and the vertical bearing capacity, that the two-linear reinforcement model of elastic-plastic material can be used to analyze the socket-spigot template supporting system, and, through node entity model analysis, that the load transfer direction greatly influences the node bearing area. Finally, this paper indicates the results of on-site application performance experiments, shows that the supporting system has adequate bearing capacity and stability, and comments on the common work performance of a socket and fastener scaffold.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.643-651
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• 1996

In this paper, to provide the possibility of various multimedia services, especially the collaborative work using the centralized control feature of the Service Node, is studied. We focused on the telewriting as the upper layer application to confirm the basic functions of the collaborative work. For this, we implement and add telewriting collaborative work function to the Service Node emulator, and terminals operating in the Windows environment are also developed. Through the tests on the system, we verify the basic functions related to the collaborative work are performed adequately, and confirm the concept of Service Node can support various type of multimedia conference services.