• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.565-573
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• 2022

Current mobile communication system is in the mid-process of conversion from 4G LTE to 5G network. According to the generalization of mobile communication services, personal information such as user's identifiers and location information is transmitted through a mobile communication network. The importance of security technology is growing according to the characteristics of wireless mobile communication networks, the use of wireless shared channels is inevitable, and security technology cannot be applied to all network system elements in order to satisfy the bandwidth and speed requirements. In particular, for security threat analysis, researches are being conducted on various attack types and vulnerability analysis through rogue base stations or attacker UE to make user services impossible in the case of 5G networks. In this paper, we established a 5G network testbed using open sources. And we analyzed three security vulnerabilities related to NAS COUNT and confirmed the validity of two vulnerabilities based on the testbed or analyzing the 3GPP standard.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2014.10a
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• pp.238-256
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• 2014

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.10a
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• pp.182-182
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• 1999

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.403-413
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• 2007

KREN(Korean Education Network), supported by government fur 20 years, had been operated and connected to many educational institutions from elementary schools to universities. From 2001, This network has been operated by a commercial network consignment organization and started to offer superb infrastructures to access various educational information conveniently. This network contributes development of Korean Information technology and promotes solidarity among educational institutions as well. Despite this achievement, KREN's effectiveness is not well recognized. Therefore, performance analysis study was carried out on KREN's achievement to verify its effectiveness, this study was to justify government's continuous support and also to find effective. This study was to justify government's continuous support and also to find effective ways of operations and maintenance fur the next step of KREN. Over 100 organizations were surveyed for performance analysis and we analyzed its results and anticipated effectiveness in this study. Cost, contribution, quality and performance were examined fur satisfaction analysis and each institution's number of students, network experiences were used as independent variables fer regression analysis to figure out effectiveness of the network. This study's result provides much information for further research which will help in the development of educational policies and maximizing KREN's effectiveness.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.654-666
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• 2019

The tactical network has several different characteristics compared with commercial internet network such as hierarchical topology, dynamic topology changing and wireless link based connectivity. For considering IP mobility management in the tactical network, current mobility management using Mobile IP(MIP) is not suitable with some reasons such as non-optimal routing paths and single point of failure. Proxy Mobile IP(PMIP) which supporting network-based mobility in hierarchical manner can provide optimal routing path in the tactical network environment, but centralized anchor is still remained a threat to the stability of the tactical network which changes its topology dynamically. In this paper, we propose PMIP-based distributed mobility management for the tactical network environment. From our design, routing paths are always configured in optimized way, as well as path is recovered quickly when the mobility anchor of user is failed. From numerical analysis, comparing to other mobility scheme, result shows that the proposed scheme can reduce packet transmission cost and latency in tactical network model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.326-328
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• 2016

While hackers in early days intended to disable and devastate the system, these days people hack and attack the network in order to steal customer's private information from the big corporate, which changes the nature of the crime to cyber attack for money, eventually causing a lot of damages. One of the most efficient ways to protect this kind of network attack is VPN, referring to Virtual Private Network. VPN is a private networking technology that makes the public network available for only those who are concerned. This paper will suggest the VPN technology that can be applied to Linux server and related protocols and figure the applicable VPN out.

• Journal of Industrial Technology
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• v.36
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• pp.71-76
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• 2016

In this study, we determined the precise coordinates of TBMs (Tidal Bench Marks), which used as the national reference points in coastal area of Korea, using a GPS data analysis SW for the academic and scientific applications, GAMIT/GLOBK. For accurate 3-D positioning of TBM locations, we performed the GPS point surveying according to the national surveying policy and also acquired the GPS data for 48 TBMs located in the western and southern coastal part of Korea. Considering the results of baseline analysis to each observation session obtained from GAMIT module, the baseline analysis was realized to be done precisely because the values of Normalized RMS (NRMS) were mostly less than ${\pm}0.20mm$. Before the network adjustment using GLOBK module, we evaluated the suitability of observations for each session by applying the chi-squared test (${\chi}^2$ test) to the degree of freedom in observed session. An overall distributions of ${\chi}^2$ test were less than 1.0 for all sessions, and the statistical of ${\chi}^2$ test showed the average, 0.267 with minimum and maximum value, 0.063 and 0.653, respectively. Finally, we analyzed the network adjustment for 48 TBMs to reduce the residuals of baseline analysis on each point by connecting with 42 permanent GPS stations in Korea. In the network adjustment procedure, we set up the weighted values of each permanent station to be allocated between 0.9 and 1.14, and also removed the observed points having residual exceeds 4-times of standard deviation ($4{\sigma}$).

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.9-23
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• 2019

The artificial intelligence speaker market is in a new age of mounting displays. This study aimed to analyze the difference of experience using artificial intelligent speakers in terms of usage context, according to the presence or absence of displays. This was achieved by using semantic network analysis to determine how the online review texts of Amazon Echo Show and Echo Plus consisted of different UX issues with structural differences. Based on the physical context and the social context of the user experience, the ego network was constructed to draw out major issues. Results of the analysis show that users' expectation gap is generated according to the display presence, which can lead to negative experiences. Also, it was confirmed that the Multimodal interface is more utilized in the kitchen than in the bedroom, and can contribute to the activation of communication among family members. Based on these findings, we propose a user experience strategy to be considered in display type speakers to be launched in Korea in the future.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.463-469
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• 2023

The aim of this study is to provide basic data that can contribute to improving successful clinical adaptation and reducing turnover of new graduate nurses by analyzing research related to reality shock experienced by new graduate nurses using text network analysis. The topics of reality shock experienced by new graduate nurses were extracted from 115 papers published in domestic and foreign journals from January 2002 to December 2021. Articles were retrieved from 6 databases (Korean DB: DBpia, KISS, RISS /International DB: Web of science, Springer, Scopus). Keywords were extracted from the abstract and organized using semantic morphemes. Network analysis and topic modeling for subject knowledge structure analysis were performed using NetMiner 4.5.0 program. The core keywords included 'new graduate nurses', 'reality shock', 'transition', 'student nurse', 'experience', 'practice', 'work environment', 'role', 'care' and 'education'. In recent articles on reality shock experienced by new graduate nurses, three major topics were extracted by LDA (Latent Dirichlet Allocation) techniques: 'turnover', 'work environment', 'experience of transition'. Based on this research, the necessity of interventional research that can effectively reduce the reality shock experienced by new graduate nurses and successfully help clinical adaptation is suggested.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.818-825
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• 2016

Network management and anomaly detection are challenges in high-speed networks due to the high volume of packets that has to be analysed. Flow-based analysis is a scalable method which reduces the high volume of network traffic by dividing it into flows. As sampling methods are extensively used in flow generators such as NetFlow, the impact of sampling on the performance of flow-based analysis needs to be investigated. Monitoring using sampled traffic is a well-studied research area, however, the impact of sampling on flow-based anomaly detection is a poorly researched area. This paper investigates flow sampling methods and shows that these methods have negative impact on flow-based anomaly detection. Therefore, we propose an efficient probabilistic flow sampling method that can preserve flow traffic distribution. The proposed sampling method takes into account two flow features: Destination IP address and octet. The destination IP addresses are sampled based on the number of received bytes. Our method provides efficient sampled traffic which has the required traffic features for both flow-based anomaly detection and monitoring. The proposed sampling method is evaluated using a number of generated flow-based datasets. The results show improvement in preserved malicious flows.