• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.362-371
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• 2013

This paper presents a framework of real-time augmented reality on 3-D mobile display with stereo camera tracking. In the framework, camera poses are jointly estimated with the geometric relationship between stereoscopic images, which is based on model-based tracking. With the estimated camera poses, the virtual contents are correctly augmented on stereoscopic images through image rectification. For real-time performance, stereo camera tracking and image rectification are efficiently performed using multiple threads. Image rectification and color conversion are accelerated with a GPU processing. The proposed framework is tested and demonstrated on a commercial smartphone, which is equipped with a stereoscopic camera and a parallax barrier 3-D display.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.10
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• pp.49-54
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• 2007

As digital contents based on 3D graphics are increased, the requirement for low power 3D graphic hardware for mobile devices is increased. We design a transformation engine for mobile 3D graphic processor. We propose a simplified transformation engine for mobile 3D graphic processor. The area of the transformation engine is reduced by merging a mapping transformation unit into a projective transformation unit and by replacing a clipping unit with a selection unit. It consists of a viewing transformation unit a projective transformation unit a divide by w nit, and a selection unit. It can process 32 bit floating point format of the IEEE-754 standard or a reduced 24 bit floating point format. It has a pipelined architecture so that a vertex is processed every 4 cycles except for the initial latency. The RTL code is verified using an FPGA.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.133-138
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• 2011

RFID system can be used to improve object recognition, map building and localization for robot area. A novel method of indoor navigation system for a mobile robot is proposed using RFID technology. The mobile robot With a RFID reader and antenna is able to find what obstacles are located where in circumstance and can build the map similar to indoor circumstance by combining RFID information and distance data obtained from sensors. Using the map obtained, the mobile robot can avoid obstacles and finally reach the desired goal by $A^*$ algorithm. 3D map which has the advantage of robot navigation and manipulation is able to be built using z dimension of products. The proposed robot navigation system is proved to apply for SLAM and path planning in unknown circumstance through numerous experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1455-1461
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• 2008

We implemented a subminiature internal antenna that is around 1 cc volume for the mobile phone. The fundamental type of studied antenna is IFA(Inverted F Antenna), and this antenna is designed to be improved efficiency and gain due to minimum current cancellation by the avoidance of multiple bending pattern. For the implementation of multiple band, helix is applied to compensate for short antenna length for low frequency band, and a 3 dimensional pattern is used for high frequency band. We made two kinds of 3D structure antenna. One is a 1 cc volume antenna for GSM/DCS band on the bare board set, and the other is a 1.5 cc volume for the GSM/USPCS mobile phone set. Measurements showed good gain performance that average gain of two antenna on each band are $-3.46{\sim}-0.45\;dBi$ and $-4.80{\sim}-3.29\;dBi$ respectively.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.31-36
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• 2018

The survival game is characterized by the ability to survive until the item is collected and the game is completed at the specified time, and the inventory function to store the item is the core of the game. Typical survival games include 'Don't Starve', 'H1Z1', and 'Lust'. The purpose of this paper is to design a 2.5D survival game that can be enjoyed by the smart device using Unity 3D engine. Because it is designed as a mobile platform, designing light inventory function using two lists rather than existing inventory function makes it easier to design than existing inventory and light design suitable for mobile. In general, it is characterized by designing a mobile game so that it does not depend on the place of the survival game.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.1020-1022
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• 2014

In this paper, we present a method for smartphone users to have a better user experience when playing 3D mobile games using the gyro sensor. We designed the rotation of the virtual camera in the game world to be proportional to the real-world's rotation. We have also made the sensitivity configuration possible for users to manipulate.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.43-52
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• 2010

In this paper, the mobile-WiMAX (m-WiMAX) using the Smart antenna technique is implemented. Experiments are performed to compare Smart antenna system with conventional single antenna system. To implement the m-WiMAX smart antenna system there are many considerations, key issues of which are symbol time acquisition, beamforming, calibration. In the paper, symbol time acquisition, beamforming, calibration are implemented in WiMAX Smart antenna system and we verified that Smart antenna system is superior to single antenna system. The experimental results show 5.5 dB performance enhancement of implemented Smart antenna system in throughput compared with a single antenna system. The experimental result is almost same as theoretical result of 6 dB.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.225-230
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• 2005

The proposed Triple-band Compact Chip Antenna using Coupled Meander line and stacked meander Structure for Mobile RFID/PCS/WiBro. The proposed antenna is designed to operate at 900, 1800, and 2350 MHz, and is realized by parasitic coupled and stacked a meander line. Meander lines are using extend length of effective current path more than monopole and contribute miniaturization. The coupled meander line controls the excitations of the Mobile RFID and PCS, stacked meander line controls the excitation of the WiBro. The proposed antenna size is $11mm\times22.5mm\times1mm$. The antenna supports 900MHz, 1800MHz and 2350MHz operations simultaneously with bandwidths of 33MHz, 230MHz and 100MHz, respectively. The proposed antenna gains are result of simulation to be -0.8dBi, 3dBi and 3.8dBi, respectively.

• The KIPS Transactions:PartD
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• v.10D no.3
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• pp.375-386
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• 2003

A rapid growth of mobile devices and a proliferation of wireless networks lead to changing the existing environment into a mobile environment. Expansion of mobile environment makes a pressing need of mobile databases, and there are several solutions to achieve it. But they still accompany with some problems. Especially, the current synchronization server that manages consistently many mobile database management systems is based on the centralized method to synchronize data between the mobile database systems. It is the major factor that causes the lower performance of the whole system. Furthermore, the fault tolerance has not been considered in the existing systems. Therefore, we suggest the mobile agent-based mobile database system in order to resolve the problems. The system, we propose in this paper, provides the high-performance of the whole system by mobile grouping, and also may support a fault-tolerance management method.

• The KIPS Transactions:PartD
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• v.12D no.3 s.99
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• pp.493-498
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• 2005

With the advances of wireless technologies and mobile computing, m-commerce is being realized for several mobile devices such as PDAs and mobile phones. Currently, service contents in m-commerce are usually newly written to meet specific characteristics of the target mobile devices, thus requiring formidable efforts. Therefore, we should exploit the Internet product information currently being provided for e-commerce. However, bringing the Internet product to mobile devices is far from straightforward due to the many limitations of mobile devices such as little memory, small displays, low processing speeds, and so forth. In this paper, we first suggest a new model to effectively adapt the Internet product information for mobile phones. We then suggest a mobile system to implement the model. We then design and implement the system. Finally, we give experiments on the system.