• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.669-672
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• 2015

Recent Internet of Things (IoT, Internet of Things) that can be applied to various fields as the development of technology has been developed a lot of service and has been developed with the service also for crop management. To manage the essential elements of soil moisture in the crop growth but existing a direct person measuring the fluid point to carry the measuring instrument, if you take advantage of the WPAN (Wireless Personal Area Network) in this paper to manage sensor data, a fixed 3 points (30, 60, 90 cm) and can be managed can be scientifically analyzed the state of growth of the crop. Open field environment is utilized as it is less disturbance of the interference and the frequency of the radio frequency signal of the structure provides a relatively comfortable environment. Therefore, WPAN building and data transmission scheme of the minimum cost is to be developed. In addition, the operation to enter low power mode, the algorithm is necessary because a lot of restrictions on the power supply applied to the sensor nodes and the gateway is constructed in the open field. In the experiment, verifying the effectiveness by using a network configuration of each of the sensor nodes and the gateway, and provides a method for time synchronization of the operation and a low power mode. The study protocol for the RF communication with the LoRa and to enhance communication efficiency is needed in the future.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.309-318
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• 2005

In order to present wireless Internet users with previously created HTML contents and applications, it is essential to research and develop the technology to efficiently convert HTML documents into documents and further provide a way to edit the WML documents. This paper describes the design and development of a WML converter and WML editor The WML converter can convert HTML pages in real time into WML documents that are suitable for the WAP environment. The WML editor enables creation and modification of WML documents in a WYSIWYG fashion. These tools enable the previous services based on HTML documents to be easily adapted to the wireless environment. The developed WML converter can be installed on a proxy server to support real time conversion of Web contents. It is superior to other converters in terms of the various image formats it supports and the improvements on the conversion of the link and frame tags. Users can continuously browse via links and also view frames. Automatic dividing of large WML documents into WML cards md user defined conversion rules are also supported. The WML editor is also integrated with the converter and provides an integrated WYSIWYG environment for creating, converting and publishing WML documents.

• The KIPS Transactions:PartA
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• v.10A no.5
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• pp.539-550
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• 2003

As the service of mobile internet has been expended, student users are increase. The computers have been widely used in a education field as the teaching tool by improvement of the multimedia contents processing and user interface. The English learning using the computers in the restricted education environment provides motivations and effective learning to learners, but still have some problem such as teaching and evaluating without consideration for differences of individual levels. In order to solve the problems and take the advantages, we propose the intelligent tutoring system for english learning with mobile technology. Overcoming limitations of the mobile environment and using proper treacher's roles,. We have applied the conventional estimation method of the intellectual learner level for students. Also, we have proposed the diagnostic function in order to determine the method of teaching-learing and item disposition that each leaner prefers. Then we have designed and implemented the expert module, providing the feedback for teaching, of the intelligent turoring system for mobile english learning. This system will be able to support the interaction between teachers and students and replace some roles of teacher in the mobile english learning.

• The Journal of Society for e-Business Studies
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• v.16 no.4
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• pp.197-220
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• 2011

The smartphone is simply beyond the means of communication equipment, to line up the turning point of mobile convergence, is recognized as a service tool of new concept the camera, game, multimedia function, digital multimedia broadcasting, mobile internet etc, that use of smartphone is working toward developed a variety and new business models. The study is empirically studied casualties that self-determination influences flow and satisfaction which is intrinsic motivation of smartphone. There are many studies on flow, is intrinsic motivation, influencing satisfaction and Loyalty, but there are little studies which variables influences flow. this study is explore causality of autonomy, competence, relatedness which are major variables of self-determination theory that studied factors effecting intrinsic motivation influencing flow and satisfaction. This study developed a research model to explain the use of smartphone, and collected 670 survey responses from the office workers of seoul S company who had experiences with such smartphone. To prove the validity of the proposed research model, SEM analysis is applied with valid 670 questionnaires. The results, firstly, autonomy positively influences flow. secondly, competence significantly influences flow. thirdly, relatedness significantly influenced flow. also, upper above results shows that flow influences satisfaction.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.53-60
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• 2006

Handover of WiBro is based on 802.16e hard handover scheme. When PSS is handover, it is handover that confirm neighbor's cell condition and RAS ID in neighbor advertisement message. Serving RAS transmits HO-notification message to neighbor RAS. Transmiting HO-notification message to neighbor RAS, it occurs many signaling traffics. Also, When WiBro is handover, It occurs many packet loss. Therefore, user suffer service degradation. LPM handover is supporting seamless handover because it buffers data packets during handover. So It is proposed scheme that predicts is LPM handover and reserves target RAS with pre-authentication. These schemes occur many signaling traffics. In this paper, we propose PSS Movement Prediction to solve signaling traffic. Target RAS is decided by old data in history cache. When serving RAS receives HO-notification-RSP message to target RAS, target RAS inform to crossover node. And crossover node bicast data packet. If handover is over, target RAS forward data packet. Therefore, It reduces signaling traffics but increase handover success rate. When history cache success, It decrease about 48% total traffic. But When history cache fails, It increase about 6% total traffic

• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.11-18
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• 2009

As a marine leisure industry has being developed and demands for leisure culture have rapidly increased, the needs for services offering marine safety and related information are growing. Accordingly, in the study I developed the contents providing server to support this with ENC agent who presents geographical information of digitalized Electronic Nautical Chart satisfying with the standard(S-57) by International Hydrographic Organization and a web searching agent who builds a database by collecting marine-related information in order to provide a variety of realtime information such as weather, fishing and news. In addition, I designed and embodied network based mobile contents which can be presented on a WIPI(Wireless Internet Platform for Interoperability) based portable handset by receiving an ENC and other processed information from server. With the results produced by such experiments, I measured a compressibility corresponding to a image compression format of electronic nautical chart transmitted and analyzed the correlation between increase in packets of requested information and the cost.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.701-704
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• 2007

Recently, More and more consumer enjoy the finance service such as settling, account transferring, stocks investment, and so via mobile device. In the mobile environment, data transferring between the devices is formatted as XML. However, the common XML file is exposed to the attack such as hacking and malignity code, to satisfy security of mobile environment is very difficult. The problem is more seriously at the open platform such as WIPI that is developed by our country. So there is enough reason to propose one system to protect the import data. In this paper, we development the system to digital signature and signature the XML document in order to protect data, and the system is observing the recommendation of the XML Signature Syntax and Processing by W3C. When designing and composition the system, we use the digital signature algorithm RSA, DSA, KCDSA, and HMAC, etc. we test the system at the open WIPI platform.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.221-230
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• 2008

We Studied current Flight Information System everyone employing, and this paper designed a next generation Ubiquitous Flight Information System. Studied a Ubiquitous Flight Information System regarding AVOD, game TV, cellular phone, cabin Internet use for a customer, and airline and control of Air Traffic Service, Air Traffic Control, in seat reservation, transportation, ticketing and luggage back-tracking and airplanes in earthly service. We Designed for a Next Generation Ubiquitous Flight Information System and for necessary for network security, system security of information security system, and derived from comparative analysis of improvement point and difference to existing Ubiquitous Flight Information System and Next Generation Ubiquitous Flight Information as was based on result of research. Present vision to aerial the result of research world of this paper related industry, and ensure safety and communication efficiency and a customer and flight satisfaction, efficiency, and will reclaim the new horizon to the Flight Information Industry.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.42-54
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• 2008

In recent years, embedded systems have been expanding their application domains from traditional embedded systems such as military weapons, robots, satellites and digital convergence systems such as celluar phones, PMP(Portable Multimedia Player), PDAs(Personal Digital Assistants) to Next Generation Personal Computers(NGPCs) such as eating PCs, wearable computers. The NGPCs are network-based, human-centric digital information devices diverged from the traditional PCs used mainly for document writing, internet searching and database management. Wearable computers with battery capacity and memory size limitations have to use real-time operating systems with small footprints and low power management techniques to provide user's QoS in spite of hardware constraints. In this paper, we have designed and implemented a low-power RTOS (called eRTOS) for wearable computers. The implemented eRTOS has 18KB footprints and the dynamic power management and the device power management schemes are adapted in it. Experimental results with wearable computer applications show that the low power techniques could save energy up to 47 %.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.403-410
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• 2008

In this paper, we investigate the performance of MMR system in Non-transparent mode. The IEEE 802.16j MMR system has two node of operation, Single-frame (in band) and Multi-frame (out band) mode. In the analysis, we assume that channel interference between MR-BS and RS, or between RSs anywhere in the given area is ignored. The performance is presented in terms of the delay and the frame efficiency by varying number of RS and BS coverage to RS coverage ratio and the maximum coverage area of a BS by varying traffic density. Analytical results show that the Single-frame is more efficient than Multi-frame in frame efficiency and coverage extension.