• English Language & Literature Teaching
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• v.17 no.4
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• pp.375-393
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• 2011

Many aspects of e-러닝 and m-러닝 have been conducted in language learning settings while few studies have examined learners'psychological attitudes in both Internet-based languages learning environment. Althoughe-Learning and m-Learningin the content of language learningshares many common aspects, the study that particularly examinesEnglish learners' psychological attitudes from both learning environments has not been conducted. Thus, the purpose of this study is to investigate group difference between e-러닝 and m-러닝 in terms of characteristics of both learning environments, including Contextual Offer, Interactivity, Enjoyment, Usefulness, Easiness, Variety, Connectivity, Satisfaction, and Learning Performance. Results showed that even if there was little difference within and among groups in English learners' feelings, learners have different attitude on Enjoyment, Easiness, and Connectivity.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.65-66
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• 2016

최근 과학의 발달로 사물에 대한 다양한 센서와 통신 기능을 부여하여 사람 대 사람 또는 사물 대 사물 서로 교류하는 개념인 IoT(Internet of Things)가 화제이다. IoT를 구성하는 요소 중에 하나인 Wireless Sensor Networks(WSN)에 대한 연구를 한다. WSN은 전쟁터의 정찰과 같은 가혹한 환경에 적용되며 이를 구성하는 센서는 제한된 자원을 가지고 있기 때문에 고장에 취약한 특성이 있다. 따라서 상호 통신이 외부 요인에 의해 단절된 네트워크의 연결 복구에 대한 연구가 지속적으로 이루어지고 있다. 본 논문에서는 이러한 WSN 네트워크의 연결 복구 방식, 연결 복구기법 및 알고리즘의 연구 동향에 대해서 서술한다.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.99-108
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• 2002

Users location management and handoff management is constructed more effective for giving satisfaction to QoS of multimedia service in Mobility network. For this, We have the HLR of IMT-2000, difference of the HLR of PCS, and connectivity Artificial Intelligent network and to provide data service of packet that is analyze to effect on the HLR. We have a study on effective for satisfaction of QoS, that is the VHE of full concepts for provide of service in the IMT-2000, packet data service for internet connectivity, for satisfaction of QoS on basis mobility network technologies of the 2nd generation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3B
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• pp.212-218
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• 2012

An Internet worm is a self-replicating malware program which uses a computer network. As the network connectivity among computers increases, Internet worms have become widespread and are still big threats. There are many approaches to model the propagation of Internet worms such as Code Red, Nimda, and Slammer to get the insight of their behaviors and to devise possible defense methods to suppress worms' propagation activities. The influence of the network characteristics on the worm propagation has usually been modeled by medical epidemic model, named SI model, due to its simplicity and the similarity of propagation patterns. So far, SI model is still dominant and new variations of the SI model, called SI-style models, are being proposed for the modeling of new Internet worms. In this paper, we elaborate the problems of SI-style models and then propose a new accurate stochastic model using an occupancy problem.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.217-219
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• 2016

The Internet of Things (IoT) is the interconnection of uniquely identifiable embedded computing devices within the existing Internet infrastructure. IoT is expected to offer advanced connectivity of devices, systems, and services that goes beyond machine-to-machine communications and covers a variety of protocols, domains, and applications. Time information is a critical piece in the IoT to support its requirements. This paper reviews conventional time keeping mechanisms in the Internet and presents issues to be considered for combining time and data in the IoT.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.65-72
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• 2020

The Internet of Things(IoT) is to build a hyper-connected society through interconnection, and on this basis, to improve the quality of life and productivity, including solving social problems, and to become the next growth engine for the nation. The open common eco-system pursued by the IoT can start with the under- standing of the word 'open'. The IoT can achieve the expected effect of lowering the barriers to entry of technology development, and in these changes, OSSW and OSHW play a very important role in accelerating IoT eco-system maturity and breaking the boundaries between industries to promote convergence. Recently, it has developed into an intelligent IoT that combines artificial intelligence (AI) with the connectivity of the IoT. Here, I will analyze the direction of development of the IoT through understanding and analysis of open source.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.25-34
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• 2006

In this paper DynaMoNET is suggested as a novel IPv6-based multi-homed mobile network architecture which is composed of nested mobile ad hoc networks dynamically coming together through wireless personal area networks. Each ad hoc network has a mobile router which may work as a root mobile router instead of fixed mobile routers in a DynaMoNET. A root mobile router provides the reliable Internet connectivity for the entire mobile network. This paper includes a innovative handover protocol for multi-homed mobile networks, network switchover algorithm considering multiple decision factors, root mobile router election process based on token-based algorithm fast root mobile router discovery algorithm and fault avoidance mechanism to support reliable Internet connectivity. Finally the system architecture of a mobile router is given in detail.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.47-52
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• 2018

Wi-Fi enabled Internet of Things (IoTs) had a substantial impact on society, economy and industry. However wireless connectivity technologies in unlicensed band such as Wi-Fi are vulnerable to interferences. They also face difficulty providing wireless connectivity over long range in dense networks due to the dynamically changed interference effect and asymmetric interference conditions. In this paper, robust acknowledgement transmission scheme is proposed for long range IoTs. According to the proposed scheme, it is possible to control the transmission rate of the transmission success rate of the response frame by adjusting the transmission rate of the response frame when the interference is present asymmetrically. It is also possible to use higher data rate when high quality link is guaranteed. The evaluation results demonstrated the proposed scheme improves the aggregate throughput by at most 9 Mbps when 20 MHz bandwidth transmission mode was adopted.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1250-1264
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• 2017

This paper presents the architecture design, implement, experimental validation of a bistatic backscatter wireless communication system in Wi-Fi network. The operating principle is to communicate a tag's data by detecting the power level of the power modulated Wi-Fi packets to be reflected or absorbed by backscatter tag, in interconnecting with Wi-Fi device and Wi-Fi AP. This system is able to provide the identification and sensor data of tag on the internet connectivity without requiring extra device for reading data, because this uses an existing Wi-Fi AP infrastructure. The backscatter tag consists of Wi-Fi energy harvesting part and a backscatter transmitter/a power-detecting receiver part. This tag can operate by harvesting and generating energy from Wi-Fi signal power. Wi-Fi device decodes information of the tag data by recognizing the power level of the backscattered Wi-Fi packets. Wi-Fi device receives the backscattered Wi-Fi packets and generates the tag's data pattern in the time-series of channel state information (CSI) values. We believe that this system can be achieved wireless connectivity for ultra- low-power IoT and wearable device.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.244-247
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• 2016

Internet of Things spotlighted by the recent growth of the country: the interest in (IoT Internet pf Things) is being maximized. According to the scale of the 2013 Machina Research 2022 yireundago IoT market it is predicting about $ 1.2 trillion. Also the number of IoT devices connected simultaneously to the 2020 worldwide reached about 2.1 billion, and is expected to require about 200 million communications link. Many of these devices in order to manage and operate them efficiently IEEE 802.15.4e, D2D, Beacon, supporting protocols such as Zigbee gateway and network Connectivity to the urgent need for a proactive response to M2M -based operating convert it to a standard protocol being. This paper supports a variety of devices with different protocols and propose the design of intelligent Gateway with integrated features to manage operations.