• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.1
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• pp.139-146
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• 2014

Through numerous mobile device technology advances, various multimedia contents is moving towards mobile devices from existing personal computer (PC). These paradigm has emerged taking into account these idea, the so-called N-Screen, N-Screen is user-centric service to provide running and sharing on everywhere via advanced smart system in C-P-N-T (Content, Platform, Network, Terminal). Therefore we must provide securing of various contents, openended platform, and user-centric service for efficient N-Screen service. For These characteristic of N-Screen, this paper propose design and implementation of user location-based N-Screen service system. The proposed system realize user location through user's smart phone and offer automatic streaming service to user. And also, we provide web service-based extended N-Screen service. Thus, user can access various device, such as laptop, tablet, and mobile device.

• ETRI Journal
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• v.37 no.4
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• pp.707-716
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• 2015

The purpose of a localization system is to estimate the coordinates of the geographic location of a mobile device. The accuracy of wireless localization is influenced by nonline-of-sight (NLOS) errors in wireless sensor networks. In this paper, we present an improved time of arrival (TOA)-based localization method for wireless sensor networks. TOA-based localization estimates the geographic location of a mobile device using the distances between a mobile station (MS) and three or more base stations (BSs). However, each of the NLOS errors along a distance measured from an MS (device) to a BS (device) is different because of dissimilar obstacles in the direct signal path between the two devices. To accurately estimate the geographic location of a mobile device in TOA-based localization, we propose an optimized localization method with a BS selection scheme that selects three measured distances that contain a relatively small number of NLOS errors, in this paper. Performance evaluations are presented, and the experimental results are validated through comparisons of various localization methods with the proposed method.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.1
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• pp.41-46
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• 2006

Ubiquitous location based services, offer helpful services anytime and anywhere by using real-time location information of objects based on ubiquitous network. Particularly, autonomous mobile robots can be a solution for various applications related to ubiquitous location based services, e.g. in hospitals, for cleaning, at airports or railway stations. However, a meaningful and still unsolved problem for most applications is to develop a robust and cheap positioning system. A typical example of position measurements is dead reckoning that is well known for providing a good short-term accuracy, being inexpensive and allowing very high sampling rates. However, the measurement always has some accumulated errors because the fundamental idea of dead reckoning is the integration of incremental motion information over time. The other hand, a localization system using RFID offers absolute position of robots regardless of elapsed time. We construct an absolute positioning system based on RFID and investigate how localization technique can be enhanced by RFID through experiment to measure the location of a mobile robot. Tags are placed on the floor at 5cm intervals in the shape of square in an arbitrary space and the accuracy of position measurement is investigated . To reduce the error and the variation of error, a weighting function based on Gaussian function is used. Different weighting values are applied to position data of tags since weighting values follow Gaussian function.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.7
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• pp.605-613
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• 2013

This research proposes a vibration pattern algorithm to implement the haptic joystick to control a mobile robot at the remote site without watching the navigation environment. When the user cannot watch the navigation environment of the mobile robot, the user may rely on the haptic joystick solely to avoid obstacles and to guide the mobile robot to the target. To generate vibration patterns, there is a vibration motor at the bottom of the joystick which is held by the user to control the motion direction of the mobile robot remotely. When the mobile robot approaches to an obstacle, a pattern of vibration is generated by the motor, and by feeling the vibration pattern which is determined by the relative position of the mobile robot to the obstacle, the user can move the joystick to avoid the collision to the obstacle for the mobile robot. To generate the vibration patterns to convey the relative location of the obstacle near the mobile robot to the user, Fuzzy interferences have been utilized. To measure the distance and location of the obstacle near the mobile robot, ultrasonic sensors with the ring structure have been adopted and they are attached at the front and back sides of the mobile robot. The precise location of the obstacle is obtained by fusing the multiple data from ultrasonic sensors. Effectiveness of the proposed algorithm has been verified through the real experiments and the results are demonstrated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3B
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• pp.224-231
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• 2006

The location information of wired 112, 119 emergency call is provided immediately by subscriber database of KT. But emergency call made by mobile phone should be ask location information to mobile network. This paper proposes the network protocol for mobile emergency service refer to TIA/EIA/J-STD-036-A with reviews about technical issues, legacy factors and related researches. The mobile emergency service is divided to mobile emergency rescue service and mobile emergency alert service. The network reference model for mobile emergency rescue service is released in domestic sector. In this paper, the interfaces between modules of the network reference model, and service scenarios, message flows are defined. Supplement to mobile emergency rescue service, the network reference model, interfaces and message flows for mobile emergency alert service are developed.

• Journal of the Korean Society for Computer Game
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• v.31 no.4
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• pp.29-36
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• 2018

The purpose of this paper is to examine the temporal and spatial characteristics of mobile games through Mikhail Bakhtin's chronotope concept in order to examine the changes of mobile games and gaming. Based on chronotope, a concept that refers to the inner relation between time and space reproduced in the novel, I examined the inner relation between the space - time experience in the mobile game platform and the reconstruction of the mobile game text. The mobile game builds the present-here world based on the player's will while superimposing the act of playing through the mixed platform of existence based on the player with the time and space of everyday life. The chronotope of a mobile game with players as platforms is created in the current space of now-here rather than connecting to the virtual world. In this paper, I review the role of chronotope reproduction in mobile games, focusing on role-playing games and location based games. In the mobile role-playing game, an unhistorical chronotope appears in which the player has a loose sense of distance around the automatic combat system, while the narrative and relational experience is weakened. In a location-based game, a chronotope of player-driven generation that generates amusing meanings through the overlap of the virtual world and the real world appears.

• Journal of the Korea Society of Computer and Information
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• v.21 no.6
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• pp.63-69
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• 2016

In this paper, we proposed the location tracking system based on MS-Based/Assisted(Mobile Station-Based and Assisted) location trigger service model with context-awareness for the intelligent location tracking of moving objects. It provides the proper resulting value that matches the context of users through the analysis about the situation of the user, physical environment, computing resource and the existing information on user input. In order to provide real-time data, we proposed the location tracking system which realizes the intelligent information such as the expecting arrival time and passing the specific area of the moving object by adopting the location trigger. So, it derives to minimize the costs of communication for the mobile object tracking applications. The proposed location tracking system based on context-awareness can be used for realtime monitoring, intelligent alarm/action, setting up of the optimized moving path, dynamic adjustment of strategies and policies. So it has the advantage to develop the application system which is aimed at optimization of the object tracking and movement.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.67-73
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• 2014

When a mobile robot performs in unknown environments, a location identification is an essential task. In this paper, we propose a location identification system that uses a sensor space without additional devices on the robot. Also the sensor space consists of a matrix of CDS sensor; when a robot was positioned on the CDS sensor, we can estimate the coordinate of the location by sensing a light. Based on KS illumination standard, experiments are performed in various environments. By evaluating the experimental results, we can show that the proposed system can be applicable to the location identification system of a moving robot.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.10-15
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• 2005

In the area of mobile communication, Location Based Services (LBS) using the location of mobile terminal to provide their services are rapidly spreading as communication network and terminal evolves. Despite the LBS are highly demanded in high speed internet area, the services are very rare due to the difficulty locating terminals. In this paper, we propose the method to locate terminals in real time and describe its implementation system. The proposed system is designed to collect the information in real time for more than a terminal connecting internet. And, the system shows high performancecollecting and generating location information through simulation tests.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.84-89
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• 2009

Personal mobile devices such as mobile phone, PMP and MP3 player have advanced incredibly. Such advance in mobile technology ignites the research related to the life-log to understand the daily life of an user. Since life-log collected by mobile sensors can aid memory of the user, many researches have been conducted. This paper suggests a methodology for user-context recognition and visualization based on the outdoor location by GPS as well as indoor location by wireless-lan. When the GPS sensor does not work well in an indoor location, wireless-lan plays a major role in recognizing the location of an user so that the recognition of user-context become more accurate. In this paper, we have also developed the method for visualization of the life-log based on map and blog interfaces. In the experiments, subjects have collected real data with mobile devices and we have evaluated the performance of the proposed visualization and context recognition method based on the data.