• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.629-633
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• 2008

Recently, there has been great interest in the application of short-range wireless communication system. In this paper, the miniaturized FM transmitter with low power is developed, and laboratory tests have been carried out. The FM transmitter uses FM radio waves to send sound from any system (MP3, PMP, PDA, MP3 Phone et.) to any nearby radio or stereo system. The transmitter is designed with $2.6cm{\times}2.6cm{\times}2.6cm$ system size. The operating voltage is 3.7 V and used the built-in storage battery. The system can use continuously during 7 hour with once charging. The transmission frequency can select one of 88.1 MHz, 88.3 MHz, or 88.5 MHz in compliance with utility condition. The channel separation ability is 40 dB. The operating temperature is $-10{\sim}+85^{\circ}C$, which use in the industry environment. Consequently, this system sis used conveniently with short distance information transmitter system at the industry field.

• The KIPS Transactions:PartA
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• v.11A no.6
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• pp.413-418
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• 2004

According as computer hardware became smaller and its performing power became improved due to the developed computer technology, clients demand more powerful accessibility to various information through getting the information at every time and every place. These needs led to the Ubiquitous computing technology which makes it possible to have access to a specific information regardless of clients' physical location. In this paper, we propose an approach that mobile host can get data from proper contents server by applying Contents Distributing Network to wireless network. By simulation, this paper proves that this approach can Improve performance by using contents server selection in wireless network. This research will contribute to realizing the Ubiquitous computing technology.

• Journal of Biomedical Engineering Research
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• v.27 no.1
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• pp.14-21
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• 2006

As information technologies are developing, the improvement of the quality of life becomes worldwide issues. Especially, to improve the quality of life of a patient suffering intermittent diseases, in addition to the some portable equipments for measuring, analyzing, and notifying the status of the patients, methods of communication for seamless transmission of the measured data over to the remote site, such as an emergency center or a hospital, are required. In this paper, we address a seamless transmission of patient monitoring data such as ECG from a moving patient to a remote site, wherever the patient may be. We divide the whole environments into two wireless communication environments: an indoor one based on WLAN and an outdoor one based on CDMA cellular network in which the patient is assumed to move anywhere. We develop algorithms, implement them on a PDA-based hardware platform, and show some of the results for handover between the two environments in addition to the data transmission for each of the two environments.

• Spatial Information Research
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• v.12 no.2
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• pp.165-179
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• 2004

With the spread of wireless internet, the interest in mobile applications and services is increasing. Korea Wireless Internet Standardization Forum has been establishing the standards for mobile platform and map service in the wireless internet environment. This study aims to present a paragon of mapping middleware that plays the role of broker for wireless internet map service: in particular, it focuses on the interoperability with generic map servers. In this study, we developed a method for applying current map servers to the wireless internet map service, and analyzed the request/response structure of the map servers which have different operation characteristics in order to allow our middleware to fully utilize the functionalities of the map servers. The middleware we developed is composed of .NET-based XML Web Services: it has a lightweight module for image map and a map representation module for choropleth map, symbol map, chart map, etc. This mapping middleware is a broker between mobile client and generic map server, and supports .NET clients and Java clients as well. Its component-based interoperability grants the extensibility for the wireless internet dedicated map servers of the future in addition to the current generic map servers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.89-95
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• 2008

The introduction of wireless information technology gives rise to new mobile services in all kinds of areas of out daily life. Mobile healthcare system is a production of composite ICT (Information and Communication Technology) which focused on signal sensing, processing, and communication in wireless environment. The mobile and wireless revolution promises not only expanded access to patient health information, but also improved patient care. In this paper, we describe a surrogate host based mobile healthcare information system which utilized Grid computing for real-time ECG signal processing. The surrogate host provides seamless interface between mobile device and Medical Grid portal. The security extension of GSI (Grid Security Infrastructure) allows mobile users to access Grid portal in a secure and convenient manner. The presented system architecture can be used as a secure enterprise mobile healthcare system for hospital physicians.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1150-1156
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• 2009

The spread of wireless Internet technology development and applications with location information in the form of location-based services are more varied. In particular, where you recognize the location of objects such as people and things, and to provide valuable services based on ubiquitous, location-based services (Ubiquitous Location Based Services: u-LBS) is emerging as an important service. In this paper precise location data to the car crash through the location and offers related service system. In this paper the precise location tracking proposed by the concept of the Rail, road, to extract the location Data Matching Data and the current location is obtained. System used in GPS Packet and information about the location of the vehicle collision and the collision time, the vehicle consists of NodeID is about. Using these data, a packet is to be created when the conflict between vehicles in the vehicle will be sent to Gateway. Gateway to the packets that were sent from the Server to determine whether the conflict is that in an emergency situation, Emergency Center for location information and let me know whether or not the conflict will be measured. Also, for those on the outside of an emergency such as a family related to the wireless terminal wireless (PDA, cell phone) is to let me know. Server get into the conflict that was configured to store information on the Database. Additionally, the proposed u-LBS system to verify the validity of the experiment was performed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.831-840
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• 2010

While Wireless Internet services were activated, many users got possible to use various Internet services without limitation in location. In particular, the demands to Wireless Internet Services are getting expanded because mobile devices that support high mobility are getting smarter. However, if a user uses various wireless networks, much limitation occurs in network setting when they move to another network. This is because there are few appropriate Handover Mechanisms to support Heterogeneous Network. So, this paper propose that Fast-Handover for Vertical Network Handover with MIH in PMIPv6 to support heterogeneous network and to reduce the handover latency time. Analysis result presented in this paper shows that by carefully selecting suitable system configuration model and parameters, suggestion has reduced latency time of 26% and packet losses of 90% (Avg.) at the maximum in comparison with original PMIPv6 handover.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.865-868
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• 2007

Recently, wireless LANs are often applied in home or office because of its various of convenience. Frequency range of wireless LANs specified by IEEE 802.11b is at 2.4 GHz. The bluetooth, the microwave oven, and the PDA(Personal Digital Assistants) uses, however, the same frequency band. So problems will be produced in these environments, such as multi-pass interference and system-to-system interference. These problems can be eliminated by using EM wave absorber. In this paper, we designed and fabricated EM wave absorber using MnZn-Ferrite, Sendust, and CPE( Chlorinated Polyethylene). The EM wave absorber with the ratio of material (MnZn-Ferrite : Sendust : CPE = 64 : 16 : 20 wt.%) has thickness of 3.7 mm and absorption ability more than 17 dB at 2.4 GHz.

• Asia Marketing Journal
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• v.15 no.3
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• pp.1-14
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• 2013

Our research brings managerial insights for developing new digital convergence of devices and services. To explain the phenomenon of device and service convergence, we combine two different approaches from separate research fields: a perceptual mapping technique generally used for segmentation in marketing and associative network analysis mobilized to understanding network structure of core and peripheral as well as the information mediating role of nodes in network science. By combining these two approaches, we provide an in-depth analysis of the associations among devices and services by assessing the centrality of device and service nodes in an associative network. This is done by examining the connections between these services and devices as well as investigating the role of mediation in the combined device-service associative network. Our results based on bi-partite network analysis of survey responses from 250 Internet Protocol (IP) television viewers show which device and which service will play the major role in future device and service convergence as well as which characteristics and functionalities have to be incorporated into future convergence. Among the devices, the mobile handset with the betweenness centrality of 0.26 appears to be the device that would lead future device convergence. Among the services, wireless broadband with the betweenness centrality of 0.276 appears to be the service on which future service convergence needs to be developed. This result is quite unexpected, since wireless broadband has a lower penetration rate than other services, such as fixed broadband and cable TV. In addition, we indicate the possibility of converging devices, such as personal digital assistant (PDA) and mobile handset, and services, such as IPTV and mobile Internet, into wireless broadband services in the future.

• The Journal of Korean Association of Computer Education
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• v.8 no.1
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• pp.25-32
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• 2005

An analysis of the case study was reported to pioneer the perceptions of teachers, students, and parents for the educational use of tablet computers. The findings showed that the amount of learning, various learning activities, interest, and motivation of learners increased and that the teachers perceived the potentiality of the tablet computer and the necessity of a training for designing mobile-based instructions.