• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.261-267
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• 2013

In this paper, the effective information transfer technique between computing device and portable device that is connected through USB interface has been studied. The proposed technique is realized by the method which portable device is perceived into optical media such as CD-ROM or CD-R/W through SCSI commands on USB interface. Through the proposed system in this study, we maximized user convenience by executing diverse works using stored data in a portable device without installing extra USB driver corresponding to portable device, when user data is transmitted between computing device and portable device. We conducted experimental tests to verify the performance of the proposed system through implementing of test system. As a result, we confirmed the technique is comparatively superior to existing method in transmitting speed and user convenience.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1786-1795
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• 2006

Portable Internet extended from wireless LAN has a large cell size, similar to a wireless mobile communication. and can provide the seamless service which offers middle-low speed mobility. IEEE 802.16e, the international standard of Portable Internet, uses PKMv2 protocol for authorization and key exchange between a MSS and a BS. This paper proposes a new protocol based on PKMv2, which can provide that MSS is able to do fast authorization with a new BS when soft handover is occurred in a MSS. Our protocol can carry out fast authorization because of reducing the number of messages and parameter exchange, public key encryption and signature in wireless network more than the previous works. It also prevents eavesdropping from an external attacker and keeps the security against impersonation attacks for both a MSS and a BS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6C
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• pp.457-464
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• 2005

Recently, Portable Internet being standardized provides fast movement with wider service range than wireless LAN does. If Portable Internet service starts, many people will use Portable Internet and thus wireless traffic is going to increase. In Portable Internet, it is important to reduce handover latency to provide user with satisfactory service when handover occurs. In IEEE 802.16e, MSS sends its own security context information to one Base Station which it will move to reduce handover latency. But this is not suitable in the situation that the BS doesn't know the security context. To reduce handover latency of proactive caching method that is to send security context information to adjacency Base Stations in advance has been proposed by[4]. In this paper we propose effective traffic management algorithm to reduce signaling network traffic caused by proactive caching method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.399-403
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• 2004

In this paper, we have analyzed the TCP throughput of Portable Internet system in 2.3GHz wireless environment with considering user's mobility speed. As the Portable Internet uses large cells compared to wireless LAM and supports user's nobility, we have adapted different wireless channel model to derive the TCP throughput of the system. We have assumed wireless channel is Rayleigh fading channel and the channel is modeled as two-state Markov model with which user's nobility speed can be considered by varying transition matrix of the model. from the simulation results, we have known that higher TCP throughput under the slow fading than under the fast fading. Because the TCP throughput is closely related to the sender's congestion control, the more congestion control is done by the sender, the lower TCP throughput we have. The more congestion control is caused in the sender under the fast fading than the slow fading so the lower TCP throughput is resulted in the fast fading environment.

• Journal of Biosystems Engineering
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• v.33 no.5
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• pp.333-339
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• 2008

The purpose of this study was to develop a portable electronic nose system to measure volatile components of agricultural and food products. Also, a graphical operating software to control the electronic nose system and to acquire signals through the Internet was developed. An array of five commercial metal oxide gas sensors was used to detect various volatile gas components of target samples. Transient and steady state signals were analyzed to extract variables related to sample states, To find optimal operating conditions of the system, several experiments were performed with different gas chambers, vacuum pumps, gas sampling temperatures, and sample container sizes. The patterns of gas sensor signals were analysed to find effects of the various conditions.

• Journal of the Korea Society for Simulation
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• v.15 no.2
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• pp.41-50
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• 2006

The high-speed portable internet service will be served in Korea sooner or later. However, the scheduling method for the packets of various service classes has not been determined clearly yet. An effective packet scheduling for various service classes requiring different QoS is necessary to increase the efficiency of radio channels that are the limiting resource. This paper proposes an improved uplink scheduling method to accommodate more calls and enhance channel efficiency. Suggested scheduling method reflects different channel conditions considering terminal's location within a cell to increase the transmission rate and utility of the channels. According to our simulation results, our proposed scheduling method shows a good performance in the aspect of throughput and capacity of uplink channels.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.51-58
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• 2020

With the emergence of the words Personal Mobility (P.M.) or Smart Mobility (S.M.), which are terms for personal transportation, the activities of related technologies are increasing with the research. Personal transportation is basically used as a short distance transportation method using electrical energy. As personal mobility became more popular, the resulting products and studies are spreading throughout the country. Most of the electric scooters, which are personal vehicles, are mostly imported from China. This is due to the fact that the price competitiveness of major components of electric scooters is owned in China. At this point, the domestic research direction is considered to be desirable in terms of composition and design of the electric scooter body. In this study, the models of portable electric scooters according to the number of wheels mounted on portable electric scooters were presented and the prototypes were produced accordingly. The number of wheels applied to the electric scooter was 2 and 3 and 4; the contents and advantages and disadvantages of the proposed portable electric scooter models were reviewed.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.39-42
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• 2004

We have designed a portable electronic nose(e-nose) system using an array of commercial gas sensors for recognition and analyzing the various odours. In this paper, we have implemented a portable e-nose system using an array gas sensors and personal digital assistants(PDA) for recognizing and analyzing volatile organic compounds(VOCs) in the field. Field screening for pollutants has been a target of instrumental development for number of year. A portable e-nose system can be substantial benefit to rapidly localize the spacial extent of a pollution or to find pollutants source. And, by using PDA, E-nose have a better function such as the easy user-interface and data transfer by internet from on- site to remote computer. We adapted the Levenberg-Marquardt algorithm based on the back-propagation and proposed the method that could be predicted concentration levels of VOCs gases after classification by separating neural network into two parts.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.3
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• pp.145-154
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• 2006

WiBro (Wireless Broadband Internet) system is going to be 9ot down to commercialization. The high portable internet system is able to be connected to the high-speed internet using 2.3 GHz frequency bandwidth, anytime and anywhere. An effective scheduling for UGS, rtPS, nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that are the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities with each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.347-353
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• 2005

WiBro (Wireless Broadband Internet) system is going to be commercialized before long. The high portable internet system is abie to be connected to the high-speed internet using 2.3 CHz frequency bandwidth, anytime and anywhere. An effective scheduling for UCS, rtPS. nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that arc the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities With each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.