• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.887-895
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• 1995

Considering that the laser range finder has the excellent resolution with respect to angular and distance measurements, a sophisticated local path planning algorithm is achieved by subgoal and sub-subgoal searching methods. The subgoal searching finds the passable ways between obstacles and selects the optimal pathway in order to reduce the moving distanced from start point to given to given goal. On the other hand, the sub-subgoal searching corrects the path given in subgoal searching in the case of which the mobile robot will collide with obstacles. Also, the effectiveness of the established local path planning and local minimum avoiding algorithm are estimated by computer simulation and experimentation in complex environment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.5
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• pp.63-69
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• 2007

propose a mobile relay structure for vehicles with multiple antennas, which can increase performances of mobile communication systems and broadcasting systems significantly. Since cell searching and DoA estimation are required for the terminal in hard handover cellular system, joint techniques for cell searching and DoA estimation are proposed to apply beamforming technique for the mobile relay with multiple antennas located at the cell boundary. The proposed cell searching and DoA estimation techniques are evaluated by computer simulation under the environment similar to WiBro system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9A
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• pp.664-672
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• 2009

In this paper, joint methods of cell searching and Direction-of-Arrival (DoA) estimation for a mobile relay station with a uniform circular array are proposed. The proposed joint estimation method for the mobile relay station is robust even when there exist symbol timing offsets between the signals received from adjacent base stations. Also, the proposed joint estimation method can reduce computational complexity and processing time, compared with the case where cell searching and DoA estimation are performed separately. Performances of the proposed method are evaluated by computer simulation under Mobile WiMAX environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6C
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• pp.530-538
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• 2010

In this paper, estimation methods of cell searching and DoA (Direction of Arrival) for mobile relay stations with a uniform linear array are proposed. The proposed methods can improve the performance of cell searching and DoA estimation by removing the effect of STOs when there exist symbol timing offsets (STOs) between the signals received from adjacent base stations,. Also, the proposed methods can improve the performance of DoA estimation significantly when there exists Doppler frequency shift caused by movement of the mobile relay station. The performances and computational complexities of the proposed cell searching and DoA methods are evaluated by computer simulation under Mobile WiMAX environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.23-28
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• 2012

Recently, due to the increasing demand for mobile devices, mobile searching market is rapidly growing. However, there is the limit of screen size, when searching for mobile devices, various results should be shown at a glance. The reason is that results are important given that up to 43 percent of people tend to check only first page. In this paper, a set of keywords for searching will be used to find out the users' interests. Users were divided into groups after going through Collaboration filtering. Therefore, the result of this experiment, reduced time for searching and improved quality of searching were confirmed.

• Journal of Communications and Networks
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• v.15 no.2
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• pp.191-197
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• 2013

In this paper, a mobile relay station (MRS) for vehicles with a beamforming antenna is considered to increase the reliability of the transmission link, particularly for the MRS at the cell boundary. A cell searching and direction-of-arrival estimation method for an MRS with a uniform linear array is proposed for OFDM-based cellular systems in a multipath environment, even with the existence of the symbol timing offsets and carrier frequency offsets. The performance of the proposed method is evaluated by computer simulation using the standard profile of IEEE 802.16e.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.429-430
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• 2018

The introduction of mobile devices increased the need to apply limitations such as mobile devices' memory, speed, energy, and bandwidth on the designs of searching images. There is a demand to reduce such limitations on searching images on the mobile phone. Hence, this paper proposes a design that adds tags on pictures to manage the images in mobile environment, allowing efficient searches and deletion of duplicate files based on the similarities of the images. The proposed method does not compromise its efficiency by increasing costs; it also reduces the volume of data needed for mobile devices.

• Journal of Internet of Things and Convergence
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• v.1 no.1
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• pp.11-19
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• 2015

The mobile and ubiquitous environment is experiencing a rapid development of information and communications technology as it provides an ever increasing flow of information. Particularly, GIS is now widely applied in daily life due to its high accuracy and functionality. GIS information is utilized through the tiling method, which divides and manages large-scale map information. The tiling method manages map information and additional information to allow overlay, so as to facilitate quick access to tiled data. Unlike past studies, this paper proposes a new architecture and algorithms for tile searching and indexing management to optimize map information and additional information for GIS mobile applications. Since this involves the processing of large-scale information and continuous information changes, information is clustered for rapid processing. In addition, data size is minimized to overcome the constrained performance associated with mobile devices. Our system has been implemented in actual services, leading to a twofold increase in performance in terms of processing speed and mobile bandwidth.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.6
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• pp.505-510
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• 2016

This paper presents a searching method of corresponding points robust to rotational error for scan-matching used for SLAM(Simultaneous Localization and Mapping) in mobile robot. A differential driving mechanism is one of the most popular type for mobile robot. For driving curved path, this type controls the velocities of each two wheels independently. This case increases a wheel slip of the mobile robot more than the case of straight path driving. And this is the reason of a drifting problem. To handle this problem and improves the performance of scan-matching, this paper proposes a searching method of corresponding points using extraction of a closest point based on rotational radius of the mobile robot. To verify the proposed method, the experiment was conducted using LRF(Laser Range Finder). Then the proposed method is compared with an existing method, which is an existing method based on euclidian closest point. The result of our study reflects that the proposed method can improve the performance of searching corresponding points.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.542-546
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• 2009

This paper introduces a Mixed-Reality based Software technology in Smart-Phone Environment. The field of Mixed-Reality in mobile environment is relatively young. but Cause to develop Mobile infra and improvement of mobile device, open-platform mobile OS, the request extended This paper suggest the method for Marker Detection and Marker Tracking method. This method is the one of some kind of a base-technology in Mixed Reality. this method is to effect to location and registration. This paper suggest the method in low CPU computing power. Using a deformable searching area, the method improve computing power. and Using a Cam-shift algorithm, we suggest a calibration free method.