• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.41-49
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• 2010

Digital broadcasting system has various affecting factors unlike analog broadcasting system, and has possibility of no signal reception in case of errors due to characteristics of digital system. And, digital broadcasting system has monitoring system for error occurrences handling various factors. ATSC mobile DTV system uses legacy frequency and provides mobile broadcasting services, and also requires monitoring systems for monitoring online broadcasting services and reporting to administrator about interference or influence with legacy systems, and error situations. In this paper, we propose efficient monitoring system which monitors online broadcasting status of ATSC mobile DTV, reports on poor signal reception, video streaming failures to administrator, and maintains reliable digital broad ca sting system.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.372-377
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• 2012

In this paper, we propose an implementation of a real-time operating system for the two-wheel mobile robot. With this implementation, we have the ability to control the complex embedded systems of the two-wheel mobile robot. The advantage of the real-time operating system is increasing the reliability and stability of the two-wheel mobile robot when they work in critical environments such as military and industrial applications. The real-time operating system which was ported to this implementation is open systems and the corresponding interfaces for automotive electronics (OSEK/VDX). It is known as the set of specifications on automotive operating systems, published by a consortium founded by the automotive industry. The mechanical design and kinematics of the two-wheel mobile robot are described in this paper. The contributions of this paper suggest a method for adapting and porting OSEK/VDX real-time operating system to the two-wheel mobile robot with the differential drive method, and we are also able to apply the real-time operating system to any complex embedded system easily.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1117-1124
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• 2015

This paper explains a web session management system for mobile web environment with BYOD(Bring Your Own Device). This system operates by enhanced secure session token. This system consists of an unique identifier, time stamp, and encryption algorithm. The Unique identifier in this system classifies each mobile device for web security based on mobile environment with BYOD. And the Time stamp in this system that determine session effectiveness for web security. Also the Cipher algorithm in this system that protects session token information for web security. This paper analysis a security of session management system running on mobile web environment using the simulation techniques. The proposed method is more suitable than the other methods under enviroment mobile web environment with BYOD.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.11
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• pp.1139-1145
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• 2008

A robust position sensing system is proposed in this paper for a ubiquitous mobile robot which moves indoors as well as outdoors. The Differential GPS (DGPS) which has a position estimation error of less than 5 m is a general solution when the mobile robot is moving outdoor, while an active beacon system (ABS) with embedded ultrasonic sensors is reliable as an indoor positioning system. The switching from the outdoor to indoor or vice versa causes unstable measurements on account of the reference coordinates and algorithm changes. To minimize the switching time in the position estimation and to stabilize the measurement, a robust position sensing system is proposed. In the system, to minimize the switching delay, the door positions are stored and updated in a database. Using the database, the approaching status of the mobile robot from indoor to outdoor or vice versa has been checked and the switching conditions are prepared before the mobile robot actually moves out or moves into the door. The reliability and accuracy of the robust positioning system based on DGPS and ABS are verified and demonstrated through the real experiments using a mobile robot prepared for this research.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.82-89
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• 2015

This study proposes a new approach to design and control for autonomous mobile robots. In this paper, we describes a fuzzy logic based visual servoing system for an autonomous mobile robot. An existing system always needs to keep a moving object in overall image. This mes difficult to move the autonomous mobile robot spontaneously. In this paper we first explain an autonomous mobile robot and fuzzy logic system. And then we design a fuzzy logic based visual servoing system. We extract some features of the object from an overall image and then design a fuzzy logic system for controlling the visual servoing system to an exact position. We here introduce a shooting robot that can track an object and hit it. It is illustrated that the proposed system presents a desirable performance by a computer simulation and some experiments.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.39-42
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• 1998

In this paper is design of signal discriminatior system for the third generation mobile telecommunication system (IMT-2000 : International mobile telecommunication service-2000) This system is basically using multiplexing method of CDMA, TDMA and FDMA that this system can be solved third generation systems problems-Frequency bandwidth, international roaming and development new architecture of mobile telecommunication systems. Designed signal discriminator system is perfectly separated three styles multiplexing method signals that more easily, nearly and economically implementation of third generation telecommunication systems. As we develop signal discriminator we will contribute to technical evolution of mobile telecommunication for third generation and stay ahead in the interior technical accumulation in addition to international intercourse as to mobile telecommunication.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.231-233
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• 2005

For the low-power design of the mobile multimedia system architecture, this paper modeling the mobile multimedia system and analysis the power consumption profile about the whole communication environment. The mobile system model consist of air interface, RIP front-end, base-band processing module and human interface. For the result of power consumption profile analysis, the power consumption of multimedia processing is above 60% compare to the whole power consumption in mobile multimedia system. To minimize the power consumption in processing module which consumes the large power, this paper proposed the Microscopic DVS technique which applies the optimum voltage for the each multimedia frame. For the simulation result, proposed power minimization technique reduce the power consumption about 30%.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.7
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• pp.679-685
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• 2006

In this paper, development of an omni-directional mobile robot with rocker-bogie link structure is addressed. The overall mobile robot system consists of the robot mechanism with embedded control architecture, wireless communication with host graphic monitoring system, and the joy stick tole-controller. In the cluttered environment with various sizes of obstacles, the omni-directionality and the traversality are required for a mobile robot, so that the robot call go around or climb over the obstacles according to the size. The mobile robot mechanism developed in this paper has both of the omni-directionality and the traversality by 4 steerable driving wheels and the 2 additional passive omni-directional wheels linked with the rocker-bogie structure. The kinematic modeling for the mobile robot is described based on the well-known Sheth-Uicker convention and the instantaneous coordinate system.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.113-115
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• 2010

We studied the methods to utilize vehicle-based mobile mapping system for field investigation work of digital map generation process. Map layers which should be checked by field investigation were analyzed to find the possibility of being checked with data from vehicle-based mobile mapping system. Also new process for digital map generation were suggested to adopt field investigation by vehicle-based mobile mapping system. We performed field investigation work on the Kangneung area by vehicle-based mobile mapping on a trial bases and compared the results with a results from usual field investigation method.

• 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.