• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.1-5
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• 2010

In this paper, we propose for improving QoS in wireless micro cellular network using Cellular-IP/PRC(Paging Route Cache) with Paging Cache and Route Cache in Cellular-IP and propose for performance of realtime and non-real time handoff service using Handoff state machine Paging Route Cache. Although the Cellular-IP/PRC technology is devised for mobile internet communication, it bas its vulnerability in frequent handoff environment. On the other hand, Cellular IP combines the capability of cellular networks to provide high performance handoff and efficient location management of active and idle mobile users with the inherent flexibility, robustness and scalability found in IP networks. Also Cellular-IP/PRC use semi-soft handoff. During semi-soft hand off a mobile host may be in contact with either of the old and new base stations and receive packets from them. Packets intended to the mobile node are sent to both base stations and buffered, so when the mobile host eventually moves to the new location it can continue to receive packets without interruption. It should be suitable for realtime service such as multimedia traffic. But, much waste of resource will occur in this method, especially for non-real time services such as FTP and E-mail. Therefore, a new algorithm that performs different handoff according to characteristic of each traffic by use of reserved field in IP packet is proposed in this thesis. This hand off state machine using differentiated handoff improves quality of services in Cellular-IP/PRC. Suggested algorithm shows better performance than existing technology in wireless mobile internet communication environment. Matlab simulation results are improving QoS, show call drop and call blocking provided to Paging Router Cache during handoff state machine in Cellular-IP/PRC.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.337-343
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• 2014

There have been many efforts to find a new way to combine software reuse and agile software development methods. This paper studies the integration of software reuse techniques in agile methods, such as Scrum. Agile methods have the advantage of accepting frequent requirement changes, while software reuse reduces development time. Despite the rapid acceptance of the Scrum method in industry, not much emphasis has been placed on active reuse in the Scrum method, and most studies have focused on introducing agile practices into software product line engineering. However, the iterative development and backlog refinement activities of the Scrum method present the advantage of facilitating software reuse. In this paper, we identify sprint characteristics and components for reuse and suggest extended backlog refinement steps. Based on the results of this research, we integrate a backlog factoring technique into backlog refinement to support reuse in agile methods. In addition, we apply the proposed technique and demonstrate a prototype of product backlog reuse in backlog refinement for an Internet shopping mall application.

• Journal of Digital Convergence
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• v.16 no.6
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• pp.205-212
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• 2018

This Study aims to propose a new information security governance model design method for streamlining security governance at national strategic level. The research method of this study is to diagnose our operational experience and to derive a new model design method. In the meantime, national information security activities were perceived to be focused on knowledge transfer, and motivation of activities and securing of executive power were weak. As a result, security blind spots and frequent occurrence of large security incidents have become unresolved challenges. National cyber security governance should be grouped together as a whole systematically from the upper policy to the lower level of performance under the responsibility of the national leader. Based on this approach, this study presented the comprehensive framework of Korean security governance model and embodied it into four architectural designs such as vision, goal, process, and performance, thus deriving the foundation for future national governance model design. Further research is needed to diagnose problems in life cycle flow, security policies based on environmental changes, and new frameworks in which all subjects participate.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.103-108
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• 2004

A Home Location Register(HLR) database system manages each subscriber's location information, which continuously changes in a cellular network. For this purpose, the HLR database system provides table management, index management, and backup management facilities. In this thesis, I propose using a two-level index method for the mobile directory number(MDN) as a suitable method and a chained bucket hashing method for the electronic serial number(ESN). Both the MDN and the ESN are used as keys in the HLR database system. I also propose an efficient backup method that takes into account the characteristics of HLR database transactions. The retrieval speed and the memory usage of the two-level index method are better than those of the T-tree index method. The insertion and deletion overhead of the chained bucket hashing method is less than that of the modified linear hashing method. In the proposed backup method, I use two kinds of dirty flags in order to solvethe performance degradation problem caused by frequent registration-location operations. I also propose using additional attributes in the HLR database scheme for location information secrecy as a suitable security method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.47-55
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• 2019

The robot is the creation of new markets and various cooperation according to the manufacturing paradigm shift. Cooperative management easy for existing industrial robots, robots work on productivity, manpower to replace the robot in every industry cooperation for the purpose of and demand increases.to exist But the industrial robot at the scene of the cooperation working due to accidents are frequent, threatening the safety of the operator. Of industrial site is configured with a robot in an environment ensuring the safety of the operator to and confidence to communicate that can do the possibility of action.Robot guard system of the need for development cooperation. The robot's cooperation through the sensors and computer vision task within a radius of the double to prevent accidents and accidents should reduce the risk. International protocol for a variety of industrial production equipment and communications opc ua system based on ultrasonic sensors and cnn to (Convolution Neural Network) for video analytics. We suggest the cooperation with the robot guard system. Robots in a proposed system is unsafe situation of workers evaluating the possibility of control.

• Journal of Digital Convergence
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• v.18 no.2
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• pp.183-195
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• 2020

Non-verbal communication cues seem to be increasingly used in social media, such as emoticon, like, follow, etc. A Q methodology study is conducted to explore this phenomenon. Via a series of focus group activities with Facebook heavy users, 34 Q statements concerning online non-verbal communication cues are derived. Different Facebook users conduct Q sorts of these statements based on frequent use basis. Analysis of Q sort result reveals three distinctive usage patterns of non-verbal communication cues in Facebook: 'safe distance keeping' type, 'observing hermit' type and 'fully dedicated aficionado' type. Discussions are made concerning different components of non-verbal communication cues utilized in these groups, respectively, which can provide a theoretical basis for social media design.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.245-258
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• 2016

This paper aims to present the way to bring about significant results through performance improvement of learning algorithm in the research applying to machine learning. Research papers showing the results from machine learning methods were collected as data for this case study. In addition, suitable machine learning methods for each field were selected and suggested in this paper. As a result, SVM for engineering, decision-making tree algorithm for medical science, and SVM for other fields showed their efficiency in terms of their frequent use cases and classification/prediction. By analyzing cases of machine learning application, general characterization of application plans is drawn. Machine learning application has three steps: (1) data collection; (2) data learning through algorithm; and (3) significance test on algorithm. Performance is improved in each step by combining algorithm. Ways of performance improvement are classified as multiple machine learning structure modeling, $+{\alpha}$ machine learning structure modeling, and so forth.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.39-55
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• 2011

Since telecommunications reforms began around world in the 1980s, many scholars have attempted to uncover its effects on the telecommunications sector. Nevertheless, research focusing largely on the impact of privatization on universal service has been relatively less frequent than other research on telecommunications reform such as the effect of competition on efficiency, investment, and universal service, and the impact of privatization on efficiency. From this perspective, this study attempted to explain the impact of the privatization of a state-owned telecommunications enterprise on universal service in Korea. This work may contribute to providing policy-makers and scholars in telecommunications with some useful policy suggestions by concretely illustrating how the privatization of Korea Telecom has influenced universal service policy formulation and the universal service system in Korea.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.13-23
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• 2016

The purpose of this study is to examine the perceptions and attitudes of pre-service early childhood education teachers about the introduction and utilization of smart education. We selected 262 pre-service early childhood education teachers. The Focus Group Interview and questionnaire were used to measure the perceptions and attitudes about the introduction and utilization of smart education. As a result, most of pre-service early childhood education teachers use smart phones and they use extra two more hours except phone calls. The most frequent usage is text. It is affected to device utilization experience in class, impact on childhood development. FGI results of pre-service early childhood education teachers for the introduction and utilization of smart education were analyzed by 2 subjects, 4 categories, 18 items.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.499-511
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• 2016

The aim of this study was to find out effect of the orthographic representation on speech sound segmentation performance. Children's performances of the orthographic representation task and the speech sound segmentation task had positive correlation in words of phoneme-grapheme correspondence and negative correlation in words of phoneme-grapheme non-correspondence. In the case of words of phoneme-grapheme correspondence, there was no difference in performance ability between orthographic representation high level group and low level group, while in the case of words of phoneme-grapheme non-correspondence, the low level group's performance was significantly better than the high level group's. The most frequent errors of both groups were orthographic conversion errors and such errors were significantly more noticeable in the high level group. This study suggests that from the time of learning orthographic knowledge, children utilize orthographic knowledge for the performance of phonological awareness tasks.