• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.17-26
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• 2008

The 1st order level network of Korea was adjusted simultaneously in 1987. After that, the 1 st order level network of Korea was adjusted simultaneously by National Geographic Information Institute in 2006. The levelling data were acquired by digital level with invar staff from 2001 through 2006. The 1st order level network consists of 36 level lines. Among them, 34 level lines comprise 11 level loops. Among 36 level lines, 4 level lines have fore & back error larger than the regulations for the 1st order levelling of NGII, Korea. Also, the closing error of 3 loops of level network exceed the regulation for the 1st order levelling of NGII. The standard error of fore and back leveling between bench marks(${\eta}_1$) are distributed between 0.2 $mm/{\surd}km$ and 1.7 $mm/{\surd}km$. The standard error of loop closing(${\eta}_2$) is 2.0 $mm/{\surd}km$. This result means that the 1st order level network of Korea qualifies for the high precision leveling defined by International Geodetic Association in 1948. As the result of the 1st order level network adjustment, the reference standard error($\hat{{\sigma}_0}$) of the level network was 1.8 $mm/{\surd}km$, which is twice as good as that of the 1st adjustment of level networks in 1987.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.199-208
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• 2021

This is an era of technology and with the rapid growth of the Internet, networks are continuously growing. Companies are shifting from simple to more complex networks. Since networks are responsible to transmit huge data which is often sensitive and a point of concern for hackers. Despite the sizes of the networks, all networks are subject to several threats. Companies deploy several security measures to protect their networks from unauthorized access. These security measures are implemented from the device level to the network level. Every security layer adds more to the security of the company's network. Firewalls are the piece of software that provides internal and external security of the network. Firewalls aim to enhance the device level as well as network-level security. This paper aims to investigate the different types of firewalls, their architecture, and vulnerabilities of the firewall. This paper improves the understanding of firewall and its various types of architecture.

• Health Policy and Management
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• v.21 no.4
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• pp.493-510
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• 2011

Objectives : This study aims to explore how social support and social network are related with health behavior. Methods : The target population was 12,449 people in Chungcheongbuk-do. The sample was accrued for the period of 3 months in 2008 by face to face interview of direct visiting from systematic sampling method. The instruments used in this study were social support, social network and health behavior. Results : There was significant difference in the level of social support and social network by sex, age, educational level, occupation, and monthly income(p<0.05). There was significant difference in the level of social support by alcohol drinking, physical exercise. There was significant difference in the level of social network by smoking, alcohol drinking, physical exercise, obesity(p<0.05). Multivarite analysis shows significant difference in the level of social instrumental support by smoking, physical exercise. It shows significant difference in the level of social emotional support by smoking. It also shows significant difference in the level of social network by smoking, physical exercise. Conclusion : These results suggest that social support and social network may be associated with health behavior. Because this study was cross sectional research, the order was not found between social support, social network and health behavior. Through a study on monitoring, we will obtain more information for relationship.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.103-113
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• 1985

This is the first part of the four-part paper describing the development of a packet-switched computer network named the KORNET In this paper, we present the overview of the KORNET, and discuss various aspects on the development of the netwo management center (NMC). The NMC acts as a nerve center of the network, performing such functions as network monitoring, subscriber and network management and routing manage-ment using operator dialogues. In the implementation of the NMC, we have developed various application softwares that include operator interface, primary/srcondary pan, session layer and packet level adaptor. As for packet, link and physical level protocols, we have modified the XODIAC X.25 originally developed by Data General, Inc. All the net-work protocols we have developed comply completely with the CCITT recommendations.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.3
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• pp.161-166
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• 2011

In this paper, for analysing the major factors giving the effect to the quality of HD level video on the multicasting service, we tried this test experiment on the College school network similar to the real service network environment. We measure the video quality distortion on the multicasting HD level video according to generating and increasing the broadcasting traffic on the situation that apply the QoS technique to the test network and not apply the QoS technique and then find out the threshold value of network factors giving the effect to the video quality distortion on the multicasting HD level video service. This paper can be used for guaranteeing the constant video quality and reducing the video quality distortion on the multicasting HD level video service.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.752-757
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• 2014

This paper attempts to evaluate the impact of power plant penetration on constraints of a transmission network and proposes a methodology based on risk level, which can evaluate the condition of the network and facilities intuitionally. Furthermore, based on this methodology, RLII(Risk Level Improvement Index) is proposed in order to establish comprehensive TNEP(Transmission Network Expansion Planning) from a viewpoint of ISO(Independent System Operator). In order to verify the proposed methods in this paper, real power systems in Incheon and Shiheung areas, south Korea are applied to the case study.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.169-178
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• 2019

Due to the characteristics of an ad hoc network without a control center, self-organization, and flexible topology, the trust evaluation of the nodes in the network is extremely difficult. Based on the analysis of ad hoc networks and the blockchain technology, a blockchain-based node-level trust evaluation model is proposed. The concepts of the node trust degree of the HASH list on the blockchain and the perfect reward and punishment mechanism are adopted to construct the node trust evaluation model of the ad hoc network. According to the needs of different applications the network security level can be dynamically adjusted through changes in the trust threshold. The simulation experiments demonstrate that ad-hoc on-demand distance vector(AODV) Routing protocol based on this model of multicast-AODV(MAODV) routing protocol shows a significant improvement in security compared with the traditional AODV and on-demand multipath distance vector(AOMDV) routing protocols.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.755-764
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.33-51
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, Maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.87-97
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• 2009

Internet network routing system is used to prevent spread and distribution of malicious data traffic. This study is based on analysis of diagnostic weakness structure in the network security domain. We propose an improved integrated multi-level protection domain for in the internal route of groupware. This paper's protection domain is designed to handle the malicious data traffic in the groupware and finally leads to lighten the load of data traffic and improve network security in the groupware. Infrastructure of protection domain is transformed into five-stage blocking domain from two or three-stage blocking. Filtering and protections are executed for the entire server at the gateway level and internet traffic route ensures differentiated protection by dividing into five-stage. Five-stage multi-level network security domain's malicious data traffic protection performance is better than former one. In this paper, we use a trust evaluation metric for measuring the security domain's performance and suggested algorithm.