• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.852-862
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• 2013

This paper proposes a target tracking control method for wheeled mobile robots with nonholonomic constraints by using a backstepping-like feedback linearization. For the target tracking, we apply a vision system to mobile robots to obtain the relative posture information between the mobile robot and the target. The robots do not use the sensors to obtain the velocity information in this paper and therefore assumed the unknown velocities of both mobile robot and target. Instead, the proposed method uses only the maximum velocity information of the mobile robot and target. First, the pseudo command for the forward linear velocity and the heading direction angle are designed based on the kinematics by using the obtained image information. Then, the actual control inputs are designed to make the actual forward linear velocity and the heading direction angle follow the pseudo commands. Through simulations and experiments for the mobile robot we have confirmed that the proposed control method is able to track target even when the velocity sensors are not used at all.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2004.11a
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• pp.323-330
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• 2004

As mobile market grows more and more fast, the mobile contents market, especially music contents for mobile phones have recorded remarkable growth. In spite of this rapid growth, mobile web users experience high levels of frustration to search the desired music. New musics are very profitable to the content providers, but the existing collaborative filtering (CF) system can't recommend them. To solve these problems, we propose an extended CF system to reflect the user's real preference by representing the characteristics of users and musics in the feature space. We represent the musics using the music contents based acoustic features in multi-dimensional feature space, and then select a neighborhood with the distance based function. Furthermore, this paper suggests a recommendation for procedure for new music by matching new music with other users' preference. The suggested procedure is explained step by step with an illustration example.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.592-595
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• 2004

Recently the numbers of patent about the technology for mobile payment with Ie or bluetooth-chip are being increased more and more. The reasons of patent increment for mobile payment are advancement of wireless internet technology and rising of customer's request for it. The customer wants to be able to pay for purchase, tax and aid with own mobile phone. So every mobile service provider applies for patents about that competitively. And in the near future the biometrics is generalized in the mobile payment system. Especially the payment service of iris recognition is significant technique in this area for the future prospect. The biometrics of iris is an accurate authentication method because it has about 250 distinguish parameters to the finger print's 30. The biometrics of iris can recognize and identify a person for 2 seconds. But the image of iris is changed by transformation of body in the life. And the existing iris authentication system has problem that can be miss-recognized. In this paper, we propose the new method that reduces miss-recognizing rate with Renewable Iris Authentication Algorithm(RIAA) in mobile system.

• Journal of Information Technology Services
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• v.13 no.4
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• pp.245-254
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• 2014

Payment system is defined as the various contracts and operating facilities for the transfer of monetary value to clear the relationship between credit and debt. Payment systems essentially require the efficient and reliable operations. Card-based payment systems are developed practically and creatively in accordance with the progress of ICT. Especially in mobile environment with intelligent mobile devices such as smart-phones and tablets, a variety of payment services are provided. Existing card-based payment services are configured by the payment transaction initiated by the merchants card acceptance and then swiping into the CAT (Card Authorization Terminal) to begin the transaction. The merchant initiated payment services are now applied to the Wireless CAT (W-CAT) for mobile environment. That kind of payment services cause many problems such the illegal card information leaks and the lingering threat of W-CAT theft. Also, the use of many W-CATs increased cost to the merchant. In this paper, we propose the card holder initiated card payment system using the intelligent mobile devices in mobile environment for solving problems of the existing merchant initiated card payment system and coping effectively with the activation of a wireless data network and changes of information technology.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1677-1680
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• 2003

In this paper, we propose the multimedia tutoring system that provides multimedia learning contents for english Loaming on mobile environment. In order to design and implement the system, we have developed mobile multimedia contents from contents modeling based on the types of item, but also mobile interface to provide learning contents for learners effectively under limitation of mobile environment. The contents server in this system creates multimedia learning contents as XML document for each learner and provides those to learners through mobile interface using Wireless Application Protocol at anytime and anyplace.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.245-247
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• 2011

For the mobile meteorological services, sensed data should be gathered at a server from various clients like as USN, mobile phone or public traffic vehicle by wireless network. The gathered data have huge volume and increase continuously, a special query method and data structure are considered. This paper studies on all query type and processing steps for the mobile meteorological services and proposes effective system structure.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.281-285
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• 2009

Mobile robot has various sensors for describing the external world. The ultrasonic sensor widely applied to the most mobile robot to detect the obstacle and environment owing to low cost, its easy to use. However, ultrasonic sensor has major problems: the uncertainty information of sensor, false readings caused by specular reflection, multi path effect, low angular resolution and sensitivity to changes in temperature and humidity. This paper describes a sensor system for map building of mobile robot. It was made of low cost PSD (Position Sensitive Detector) sensor array and high speed RISC MPU. PSD sensor is cost effective and light weighting but its output signal has many noises. We propose heuristic S/W filter to effectively remove these noises. The developed map building sensor system was equipped on a mobile robot and was compared with ultrasonic sensor through field test.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1889-1892
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• 2002

In this paper, we propose the self-autonomous algorithm for mobile robot system (MRS). The proposed mobile robot system which is learned by learning with the neural network can trace the target at the same distances. The mobile robot can use ultrasonic sensors and calculate the distance between target and mobile robot. By teaming the setup distance, current distance and command velocity, the robot can do intelligent self-autonomous drive. We use the neural network and back-propagation algorithm as a tool of learning. As a result, we confirm the ability of tracing the target with proposed mobile robot.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.71-76
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• 2019

In this paper, we propose a simple one-click marketing solution for mobile devices which can advertise a product which is embedded in a mobile video while watching the video on a smartphone. If a specific product of interest appears in the video to the user, one can simply click on the product in the video and a pop-up window with information about the product is proposed. The implementation of the system is expected to enable users to gain real-time information about the product while watching the video without having to search for the product again after watching the movie, and thereby facilitating more mobile commerce. We use a two-fold system to prevent the failure of tracking which often occurs on a single online tracking system, so that the user cannot always get the commercial product information.

• 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.