• Journal of Industrial Technology
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• v.28 no.B
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• pp.245-250
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• 2008

Recently, mobile devices have supported wireless LAN as well as bluetooth, where the services such as heterogeneous network access and seamless mobility connection are important. Even though the mobility and physical network might be varied, an efficient communication mechanism for the network access and a robust mobility management of mobile devices are needed. In this paper, we design and implement a Bluetooth system with mobile LAN access capability. The proposed system has the following features; 1) IP connection is enabled by BENP in the link layer, 2) The networks devices of heterogeneous mobile devices are integrated into a single virtual network interface, 3) IP mobility between the bluetooth and wireless LAN is supported by mobile IP. The experimented results show that the packet loss and delay time during the handover duration is reduced by predicting the handover among different networks followed by the setup of any required parameters in advance.

• Journal of Environmental Impact Assessment
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• v.5 no.1
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• pp.79-85
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• 1996

Simultaneous monitoring in many locations is necessary to evaluate the air quality and analyze future trend of a city, For this purpose, it is essential to install air pollution monitoring network. The first automatic air pollution monitoring network was introduced Seoul in 1973. As of 1995, 20 monitoring stations are now in operation. Concerning the management of the air pollution monitoring network, there was some argument among the relavant scholars, non-governmental organization(NGO) and the government organization. So far, there was no extensive evaluation and analysis about the network. The purpose of this study was to evaluate the representativeness of air quality monitoring network through actual measurement of the concentration of the air pollutant. The concentration of NOx was extensively measured widely in Seoul area three times using the TEA simple measuring technique. Even the judgement level for the area representativeness was lowered to 80%, Ssangmun-dong monitoring station tend to overestimate the pollutant concentration of the covered area. While, Sinlimdong monitoring station tend to underestimate the pollutant concentration of the covered area.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.234-237
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• 2016

Address Resolution Protocol (ARP) is used for mapping a network address to physical address in many network technologies. However, since ARP protocol has no security feature, it always abused by attackers for performing ARP-based attacks. Researchers presented many technologies to improve ARP protocol, but most of them require a high implementation cost or scarify the network performance for using ARP protocol securely. In this paper, we present an ARP-disabled network system to neutralize the ARP-based attacks. "ARP-disabled" means suppress the ARP messages like request, response and broadcast messages, but not the ARP table. In our system, ARP tables are used for managing static ARP entries without prior knowledge (e.g. IP, MAC list of client devices). This is possible because the MAC address was designed to be derived from IP address. In general, our system is safe from the ARP-based attacks even the attacker has a strong power. Moreover, we saved network bandwidth by disabling the ARP messages.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.187-188
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• 2006

In CDMA based mobile communication network, signaling messages are routed through Signaling Transfer Point(STP) which is responsible for MTP layer 3 switching. As WCDMA based UMTS network is considered as next generation technology allowing global roaming services, all nodes in networks have their own identity number called Global Title(GT). Therefore, it is essential to introduce Signaling Gateway(SG) responsible for SCCP layer switching to solve the problem each node has all GT tables including even all overseas nodes. In this paper, we propose the signaling network architecture in UMTS networks using SG and we show that we can reduce CAPEX and OPEX in each node. To show the validity of the proposed method some simulations are given in which the results can be expected by intuitive observation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.11
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• pp.51-57
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• 2014

This paper presents an algorithmic type computing technique of process coefficient in predicting model of temperature for reheating furnace and also suggests a design method of neural network model to find an adequate value of process coefficient for arbitrary operating conditions including test conditons. The proposed neural network use furnace temperature, line speed and slab information as input variables, and process coefficient is output variable. Reasonable process coefficients can be obtained by an algorithmic procedure proposed in this paper using process data gathered at test conditons. Also, neural network model output equal process coefficient under same input conditions. This means that adquate process coefficients can be found by only computing neural network model without additive test even if operating conditions vary.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.301-302
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• 2013

LTE is the outstanding technology to transfer the data and voice. LTE consists of several nodes to transfer data. In case of the failure in the node of LTE, it could not support the service. So telecommunication-providers set up the back-up system for the simultaneous service-provision. But there is still the problem it comes to the network. Even though there is a back-up system, it would be useless the network is down. We propose the scheme to support the service in the case of this network problem in the LTE network. This scheme reduces 23% load in the LTE network in the case of the HSS node's failure or the network to the HSS nodes.

• Journal of Korean Society of Forest Science
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• v.84 no.1
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• pp.63-70
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• 1995

This paper discusses applications of neural network to stand stocking control problems. The scope of this research was to develop a neural network model for finding optimal stand management regimes and examining the performance of the model for field application. Performance was analyzed in consideration of the number of training examples and structural aspects of neural network. Research on network performance was based on extensive optimization studies for pure longleaf pine(Pinus palustris) stands. For experimental purposes. an existing nonlinear even-aged stand optimization model with a whole-stand growth and yield simulator was used to generate data samples required for the performance analysis.

• International Journal of Internet, Broadcasting and Communication
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• v.6 no.1
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• pp.5-8
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• 2014

Social networking services that connect a person to other people are attracting our attention and various types of on-the-network services are provided. Library has been playing a role of social media by providing with materials such as books and magazines, and with a place for reading, studying, getting lectures, etc. In this paper, we present a method for finding candidates of groups of the library's patrons who share interest areas by utilizing the loan records, which are obtainable by every library. Such a homogeneous group can become a candidate for a study group, a community for exchange ideas, and other activity group. We apply the method to a collection of loan records of a university library, find some problem to be solved, and propose measures for more detailed solutions. Even though the potential group finding problem still remains a lot of problems to be solved, its potential importance is very high and thus to be studies even more for future applications.

• Journal of The Korean Association For Science Education
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• v.7 no.2
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• pp.61-70
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• 1987

This paper was made for the purpose of examining middle school student's conception about force and motion. Using questionaire method. this research was executed to 180 students at a middle school in Seoul. Questions were as following; 3 questions about relation of the direction of force and that of motion in case of throwing a ball up, 2 questions about parabolic motion. 1 question about inertia. and 1 question about action and reaction. The way of answering was both selecting and explaining the students' thought about questions. Network analysis was used for analyzing students' various responses. Through the analysis. some types of students' thought were revealed. As a result the representation of their response was motion implies force which had been discovered by earlier researchers. Even though students had learned about force and motion in the classroom. their ideas were unchanged or even reinforced wrongly in some case.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.75-82
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• 2022

Medical data is one of the data that must be kept in safe containers, far from intrusion, viewing and modification. With the technological developments in hospital systems and the use of cloud computing, it has become necessary to save, encrypt and even hide data from the eyes of attackers. Medical data includes medical images, whether they are x-ray images of patients or others, or even documents that have been saved in the image format. In this review, we review the latest research and the latest tools and algorithms that are used to protect, encrypt and hide these images, and discuss the most important challenges facing these areas.