• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.1-6
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• 2009

Localization of nodes is a key technology for application of wireless sensor network. Having a GPS receiver on every sensor node is costly. In the past, several approaches, including range-based and range-free, have been proposed to calculate positions for randomly deployed sensor nodes. Most of them use some special nodes, called anchor nodes, which are assumed to know their own locations. Other sensors compute their locations based on the information provided by these anchor nodes. This paper uses a single mobile anchor node to move in the sensing field and broadcast its current position periodically. We provide a weighted centroid localization algorithm that uses coefficients, which are decided by the influence of mobile anchor node to unknown nodes, to prompt localization accuracy. We also suggest a criterion which is used to select mobile anchor node which involve in computing the position of nodes for improving localization accuracy. Weighted centroid localization algorithm is simple, and no communication is needed while locating. The localization accuracy of weighted centroid localization algorithm is better than maximum likelihood estimation which is used very often. It can be applied to many applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.817-820
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• 2009

Recently, various integrated service comes true by a development of a mobile internet technology and Internet. However, much mobile internet contents should be developed to provide integrated service of good quality and does. Existing Internet contents consists of contents of a HTML base and uses in a mobile internet environment by restriction of mobile internet device, but there is a difficulty. In this paper, we was compatible with existing Internet contents in mobile internet, and wire Internet and wireless Internet contents came, and a conversion was able and designed a XML-based on mobile document conversion system that it was possible with various mobile contents.

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.1177-1190
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• 2009

In this paper, we propose a fuzzy proxy cache scheme for caching web documents in mobile base stations. In this scheme, a mobile cache model is used to facilitate data caching and data replication. Using the proposed cache scheme, the individual proxy in the base station makes cache decisions based solely on its local knowledge of the global cache state so that the entire wireless proxy cache system can be effectively managed without centralized control. To improve the performance of proxy caching, the proposed cache scheme predicts the direction of movement of mobile hosts, and uses various cache methods for neighboring proxy servers according to the fuzzy-logic-based control rules based on the membership degree of the mobile host. The performance of our cache scheme is evaluated analytically in terms of average response delay and average energy cost, and is compared with that of other mobile cache schemes.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.2
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• pp.62-67
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• 2011

Embedded device that can support mobile computing environment has been popular recently. In this study, we propose a new robot application based on embedded device to control a mobile robot using a touch-based remote interface with information display of robot trajectory and sensors. We developed the robot application using Microsoft's.Net Compact Framework and Zigbee data communication with Windows CE kernel based embedded device. In experiment, we evaluated the feasibility and the effectiveness of the proposed system by showing a remote robot control using touch interface and a information display of the robot.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.47-54
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• 2015

The popularity and adoption of smart-phones has greatly stimulated the spread of mobile malware, especially on the popular platforms such as Android. The fluidity of application markets complicate smart-phone security. There is a pressing need to develop effective solutions. Although recent efforts have shed light on particular security issues, there remains little insight into broader security characteristics of smart-phone application. Now, the analytical methods used mainly are the reverse engineering-based analysis and the sandbox-based analysis. Such methods are can be analyzed in detail. but, they take a lot of time and have a one-time payout. In this study, we develop a system to monitor that mobile application permissions at application update. We had to overcome a one-time analysis. This study is a service-based malware analysis, It will be based will be based on the mobile security study.

• Journal of the Korea Society of Computer and Information
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• v.22 no.12
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• pp.17-25
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• 2017

In this paper, we have implemented a low-cost mobile robot supporting the person tracking by detection using RGB-D cameras and ROS(Robot Operating System) framework. The mobile robot was developed based on the Kobuki mobile base equipped with 2's Kinect devices and a high performance controller. One kinect device was used to detect and track the single person among people in the constrained working area by combining point cloud data filtering & clustering, HOG classifier and Kalman Filter-based estimation successively, and the other to perform the SLAM-based navigation supported in ROS framework. In performance evaluation, the person tracking by detection was proved to be robustly executed in real-time, and the navigation function showed the accuracy with the mean distance error being lower than 50mm. The mobile robot implemented has a significance in using the open-source based, general-purpose and low-cost approach.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.4
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• pp.281-286
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• 2010

We propose a space and time based sensor fusion method and a robust landmark detecting algorithm based on sensor fusion for mobile robot navigation. To fully utilize the information from the sensors, first, this paper proposes a new sensor-fusion technique where the data sets for the previous moments are properly transformed and fused into the current data sets to enable an accurate measurement. Exploration of an unknown environment is an important task for the new generation of mobile robots. The mobile robots may navigate by means of a number of monitoring systems such as the sonar-sensing system or the visual-sensing system. The newly proposed, STSF (Space and Time Sensor Fusion) scheme is applied to landmark recognition for mobile robot navigation in an unstructured environment as well as structured environment, and the experimental results demonstrate the performances of the landmark recognition.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.490-493
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• 2020

Using AR technology, which has recently emerged as an innovative technology, AR mobile application for infants was planned. In the form of combining play and education, children's interest is aroused and access to education to various fields is increased. Unity 3D Engine and Vuforia SDK were mainly used to design Android-based mobile applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.802-804
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• 2017

Nowadays the development of mobile systems occupies significant part of our life, and users using mobile phones are demanding the utilization of differentiated spatial information. A study on application which provides information according to individual location information such as mobile advertisement is conducted for the location-based mobile service. In order to allow mobile phone users to share information based on local information, this paper proposes a mobile sharing system which combines social networks and location-based service to provide efficient information based on location information in mobile phones. The application can be provided with information associated with its location when the mobile phone user arrives at a specific location. Another proposed method focuses on providing more appropriate services for individual situations compared to other applications, and can contribute to expanding social networking functions to facilitate information sharing among users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1876-1889
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• 2013

Packet-based mobile multimedia services for the Internet differ with respect to their resource requirements, performance objectives, and resource usage efficiencies. Nonetheless, each mobile terminal should support a variety of multimedia services, sometimes even simultaneously. This paper proposes a sub-channel allocation scheme based on multi-level priority for supporting mobile multimedia services in an Orthogonal Frequency Division Multiple Access (OFDMA) system. We attempt to optimize the system for satisfying the Quality of Service (QoS) requirements of users and maximize the capacity of the system at the same time. In order to achieve this goal, the proposed scheme considers the Signal-to-Interference-plus-Noise Ratio (SINR) of co-sub-channels in adjacent cells, the Signal-to-Noise Ratio (SNR) grade of each sub-channel in the local cell on a per-user basis, and the characteristics of the individual services before allocating sub-channels. We used a simulation to evaluate our scheme with the performance measure of the outage probabilities, delays, and throughput.