• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.92-100
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• 2004

A service robot is expected to be useful in indoor environment such as a hotel, a hospital and so on. However, many service robots are driven by wheels so that they cannot climb stairs to move to other floors. If the robot cannot use elevators. In this paper, the mobile manipulator system was developed, which can operate numeral buttons on the operating panel in the elevator. To perform this task, the robot is composed of an image recognition module, an ultrasonic sensor module and a manipulator. The robot can recognize numeral buttons and an end-effector in manipulator by the vision system. The Learning vector quantization (LVQ) algorithm is used to recognize the number on the button. The barcode mark on the end-effector is used to recognize the end-effector. The manipulator can push numeral buttons using informations captured by the vision system. The proposed method is evaluated by experiments.

• The Journal of Society for e-Business Studies
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• v.12 no.2
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• pp.1-16
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• 2007

Recently the computing environment has been moved to open architectures that include Web technologies. Web Service is one of import component of the new paradigm. This paper presents a design and implementation of GIS Web Service for mobile devices. As many mobile devices are equipped with GPS (Global Positioning System), it is required to handle the position information more effectively. We have extended the proxy program in the client device to actively send the context information to the server. Based on the context information the server determines the optimal service mode to a particular client. A working example of location?based GIS Web Service is also presented. By using Web Service standards and XML messages we can achieve the maximal interoperability for heterogeneous mobile devices.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.12
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• pp.907-917
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• 2006

In this paper, we propose a strategy to improve fault-tolerance and scalability of replicated services in mobile agent systems by applying an appropriate passive replication protocol for each replicated service according to whether the service is deterministic or non-deterministic. For this purpose, two passive replication protocols, PRPNS and PRPDS, are designed for non-deterministic and deterministic services respectively. They both allow visiting mobile agents to be forwarded to and execute their tasks on any node performing a service agent, not necessarily the primary agent. Especially, in the protocol PRPDS, after a backup service agent has received each mobile agent request and obtained its delivery sequence number from the primary service agent, the backup is responsible for processing the request and coordinating with the other replica service agents. Therefore, our strategy using the two proposed protocols can promise high scalability of replicated services a large number of mobile agents attempt to access in mobile agent systems. Our simulation results show that the proposed strategy performs much better than the one using only the traditional passive replication protocol.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.371-375
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• 2007

In this paper, we have implemented the device management system to upgrade T-PAK software in mobile phone. The hybrid scheduling method and selective upgrade method are proposed. Hybrid scheduling method is based on distribution of delivery data in accordance with network traffic load and service priority from device management server to mobile phone. Selective upgrade method manages DSL classified by T-PAK software version to be upgrade using version management established in OMA DM SCOMO. Key mechanism of selective upgrade method is to only deliver DSL to be replaced to the mobile phone. We made an experiment on two methods using MS-700T terminals. The experimental result shows that the proposed method is faster than normal from delivery time standpoint.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.591-597
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• 2008

With the established voice service, the data service is increasing in the field of mobile telecommunications in these days. Also, the data service develops into the form of multimedia service which combines various media. However, it is limited to provide QoS(Quality of Service) for the multimedia using the established network which manages all the data in sam: rule. So, this paper suggests the network architecture which assures QoS of multimedia data by applying MPLS(Multi-Protocol Label Switching) to the core network. Especially, we analyze the efficiency of the network combining Mobile IP network based on the WLAN(Wireless LAN) and core network based on MPLS through by network simulations using QualNet.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.125-128
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• 2004

Although the current VoIP service is limited within the wire network, the future network will be a united network of wire/wireless. It is required that the study on the granting plan of numbering system by not considering the simple VoIP service but considering the entire network of wire/wireless. In this paper, we proposed a desirable VoIP service activation plan in mobile network suited to the future network by considering on VoIP service and mobile VoIP service.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.335-338
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• 2005

In this paper, we propose a downlink power control scheme to apply in the unequal error protection multi-code CDMA mobile medicine system. The mobile medicine system contains (i) blood pressure and body temperature measurement value, (ii) ECG medical signals measured by the electrocardiogram device, (iii) mobile patient's history, (iv) G.729 audio signal, MPEG-4 CCD sensor video signal, and JPEG2000 medical image. By the help of the multi-code CDMA spread spectrum communication system with downlink power control scheme and unequal error protection strategy, it is possible to transmit mobile medicine media and meet the quality of service. Numerical analysis and simulation results show that the system is a well transmission platform in mobile medicine.

• The Journal of Society for e-Business Studies
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• v.7 no.1
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• pp.35-50
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• 2002

Recently, payment method is one of the most hot issues for transaction of contents in mobile and internet markets. Many kinds of mobile contents services are rapidly growing with the combination of internet application services. Payment method algorithms are demanded for the stable transaction between producer and consumer. Security protocol algorithms are widely adapted for mobile Platform terminals. In this Paper, we described security mechanism for the current wireless internet services and compared with the performance result. There are security protocols that based on java machine platform or WAP protocols. The system is based on J2ME technology for the java mobile platform. Based on this technology, a security system is proposed for the service of mobile commerce electronic payment. The system is designed for the stability of transaction so that it enables to apply into many kinds of internet payment system.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.717-719
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• 2004

Currently mobile devices change rapidly our life and they have considerable influences over many parts of our society. If the mobile device is applied to a control system, the usability of the control system is increased with its convenient accessibility and mobility. This paper realizes a motor control system by using a mobile device. The device uses Intel Xscale PXA-250 in which Widows CE is ported. The device is very popular at the applications of mobile devices. Also we consider its application to a mobile robot such as home service robot.

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.126-138
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• 2008

This paper proposes the preservation method that can effectively process short messages at mobilePOST SMSC(Short Message Service Center) platform on CDMA(Code Division Multiple Access). There are three techniques for the preservation method. First one is shared memory technique where several processes within the system share same memory to process transmission of short messages with maximum performance. Second one is to back-up messages in shared memory to the file system to prevent lost during system initialization or other unstable period. Third technique is that when transmission of short message was completed, finished message is moved from the shared memory to relational database for accounting purposes.