• 한국IT서비스학회지
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• 제13권3호
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• pp.77-92
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• 2014

Korean entertainment companies like SM entertainment, YG and JYP contribute enormously to the recent K-pop fever. They expand their businesses aggressively to foreign markets which has been successful. This paper seeks to find out their precise strategies to succeed in the global market. Our study focus on SM entertainment which manages successively in the Asian market. As a result, one of their successful strategies on the global market is localization. They rearrange a group with in the members to suit into the local market : for instance, Super Junior, representative boy group, has rearranged and reformed to Super Junior M (mandarin), Super Junior happy (for Japan market), etc. Coopration with SNS (Social Network Service) is another successful strategies of SM Entertainment : page views of K-pop on Youtube achieved more than 0.8 billion in 2013. Furthermore, for marketing, many members play an advertizing model for global products.

• Korean Journal of Mathematics
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• 제22권3호
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• pp.429-441
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• 2014

In this work we study two a posteriori error estimators of hierarchical type for lowest-order mixed finite element methods. One estimator is computed by solving a global defect problem based on the splitting of the lowest-order Brezzi-Douglas-Marini space, and the other estimator is locally computable by applying the standard localization to the first estimator. We establish the reliability and efficiency of both estimators by comparing them with the standard residual estimator. In addition, it is shown that the error estimator based on the global defect problem is asymptotically exact under suitable conditions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.831-833
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• 2004

In this paper, an obstacle avoidance algorithm is proposed for a network-based robot considering network delay by distribution. The proposed algorithm is based on the VFH(Vector Field Histogram) algorithm, and for the network-based robot system, in which it is assumed robot localization information is transmitted through network communication. In this paper, target vector for the VFH algorithm is estimated through the robot localization information and the measurement of its delay by distribution. The delay measurement is performed by time-stamp method. To synchronize all local clocks of the nodes distributed on the network, a global clock synchronization method is adopted. With the delay measurement, the robot localization estimation is performed by calculating the kinematics of the robot. The validation of the proposed algorithm is performed through the performance comparison of the obstacle avoidance between the proposed algorithm and the existing VFH algorithm on the network-based autonomous mobile robot.

• IEIE Transactions on Smart Processing and Computing
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• 제1권2호
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• pp.106-116
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• 2012

The huge success of location-aware applications has called for the rapid development of an alternative positioning system to the global positioning system (GPS) for indoor localization based on existing technologies, such as 802.11 wireless networks. This paper proposes the Wireless MAC Processor Positioning System (WMPS), which is a localization system running on off-the-shelf 802.11 Access Points and based on the time-of-flight ranging of users' standard terminals. This paper proves through extensive experiments that the propagation delays can be measured with the accuracy required by indoor applications despite the different noise components that can affect the result: latencies of the hardware transreceivers, multipath, ACK jitters and timer quantization. Key to this solution is the choice of the Wireless MAC Processor architecture, which enables a straightforward implementation of the ranging subsystem directly inside the commercial cards without affecting the basic DCF channel access algorithm. In addition to the proposed measurement framework, this study developed a simple and effective localization algorithm that can work without requiring any preliminary calibration or device characterization. Finally, the architecture allows the measurement methodology to be adjusted as a function of the network load or propagation environments at the run time, without requiring any firmware update.

• 로봇학회논문지
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• 제15권4호
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• pp.357-364
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• 2020

Indoor localization using an artificial marker plays a key role for a robot to be used in a service environment. A number of researchers have predefined the positions of markers and attached them to the positions in order to reduce the error of the localization method. However, it is practically impossible to attach a marker to the predetermined position accurately. In order to visualize the position of an object in the environment based on the marker attached to them, it is necessary to consider a change of marker's position or the addition of a marker because of moving the existed object or adding a new object. In this paper, we studied the method to estimate the artificial marker's global position for the visualization of environment. The system calculates the relative distance from a reference marker to others repeatedly to estimate the marker's position. When the marker's position is changed or new markers are added, our system can recognize the changed situation of the markers. To verify the proposed system, we attached 12 markers at regular intervals on the ceiling and compared the estimation result of the proposed method and the actual distance. In addition, we compared the estimation result when changing the position of an existing marker or adding a new marker.

• Journal of Positioning, Navigation, and Timing
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• 제9권3호
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• pp.183-189
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• 2020

In emergency rescue situations, the localization accuracy of the rescue requestor is a very important factor in determining the success or failure of the rescue. Indoors where Global Navigation Satellite System (GNSS) is not operated, there is no choice but to use Wi-Fi or LTE signals. However, the performance of the current emergency rescue system utilizing those RF signals is exceedingly low. In this study, the effectiveness of the surface correlation technology using the accumulated signal pattern of RF signals was verified in relation to the emergency localization technology. To validate the proposed system, we configured and tested an emergency rescue scenario in multi-floors building. When the emergency rescue was requested, it was confirmed that the initial localization error was large owing to the short length of the accumulated signal pattern. However, the localization error decreased over time, which eventually led to the accurate location information being delivered to the rescuer.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1606-1611
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• 2005

The goal of this paper is to develop a self localization of mobile robot using UHF RFID landmark. We present landmark, a location sensing archetype system that uses UHF Radio Frequency Identification (UHF RFID) technology for locating objects inside buildings. The major advantage of landmark is that it improves the overall accuracy of locating objects by utilizing the concept of reference tags. Based on experimental analysis, we demonstrate that passive UHF RFID is a viable and cost-effective candidate for indoor location sensing. We conduct a series of experiments to evaluate performance of the positioning of the landmark System. In the standard setup, we place RF Reader which has two antennas and 25 tags in our lab. This research uses the assumption-based coordinates (ABC) algorithm[3] for determining the localization of robot. Also, we show how Radio Frequency Identification (UHF RFID) can be used in robot-assisted indoor navigation for the visually impaired. The experiments illustrate that passive UHF RFID tags can act as reliable landmark that trigger local navigation behaviors to achieve global navigation objectives.

• 한국정보통신학회논문지
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• 제12권2호
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• pp.385-390
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• 2008

무선 센서 노드의 거대한 네트워크를 통해서 환경을 감시하려는 연구가 매우 활발히 진행되고 있다. 무선 센서 노드들은 매우 작고, 가볍고, 비용이 저렴하여야 한다. 네트워크 안에서 주어진 노드가 어디에 물리적으로 놓여져 있는지를 알아내는 위치인식은 무선 센서 네트워크에서 아주 중요한 문제들 중의 하나이다. 그러나 노드의 크기 제한, 비용 등의 제약조건에 의해 GPS사용을 배제한 간단한 위치인식 방법이 요구된다. 본 논문에서는 RF 통신을 사용하는 건물 밖의 환경에서 위치인식을 위한 아주 단순한 접속성를 이용한 방법을 제안한다. 제안된 방법은 모의실험을 통해 그 효용성을 입증한다.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제1권1호
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• pp.43-54
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• 2012

본 논문에서는 야지 환경에서 동작하는 무인이동로봇에서 획득한 3차원 LIDAR (Light Detection and Ranging) 센서 정보와 로봇이 이동하는 지형의 3차원 DSM (Digital Surface Map)에서 정사윤곽선(Ortho-edge) 특징영상을 생성하고 정합하여 로봇의 현재 위치를 추정하는 기술을 제안한다. 최근의 무인이동로봇의 위치 인식에 대한연구는 GPS (Global Positioning System), IMU (Inertial Measurement Unit), LIDAR 등의 위치인식 센서를 융합하는 경우가 많아지고 있다. 특히 LIDAR에서 획득한 거리정보를 ICP(Iterative Closest Point) 기반의 기하정합으로 로봇의 위치를 추정하는 기술이 개발되고 있다. 그러나 이동로봇에서 획득한 센서 정보는 DSM의 센싱 방향과 큰 차이차이가 있어 기존의 기하정합 기술을 사용하는데 어려움이 있다. 본 논문에서는 서로 다른 센싱 방향에서 획득한 3차원 LIDAR 거리정보와 DSM에서 정사윤곽선이라는 특징 영상을 생성하고 이들을 정합하여 로봇의 위치를 추정하는 새로운 기술을 제안한다. DSM으로부터 현재 시점의 정사윤곽선 영상을 생성하는 방법, 전방향 LIDAR 거리센서에서 정사윤곽선 영상을 생성하는 방법, 그리고 정사윤곽선 영상의 정합 기술을 설명하였다. 실험에서는 다양한 주행 경로에 대한 위치 추정의 오차를 분석하고 제안 기술의 성능의 우수성을 보였다.

• Journal of Positioning, Navigation, and Timing
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• 제6권4호
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• pp.159-166
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• 2017

The position of autonomous driving vehicle is basically acquired through the global positioning system (GPS). However, GPS signals cannot be received in tunnels. Due to this limitation, localization of autonomous driving vehicles can be made through sensors mounted on them. In particular, a 3D Light Detection and Ranging (LIDAR) system is used for longitudinal position error correction. Few feature points and structures that can be used for localization of vehicles are available in tunnels. Since lanes in the road are normally marked by solid line, it cannot be used to recognize a longitudinal position. In addition, only a small number of structures that are separated from the tunnel walls such as sign boards or jet fans are available. Thus, it is necessary to extract usable information from tunnels to recognize a longitudinal position. In this paper, fire hydrants and evacuation guide lights attached at both sides of tunnel walls were used to recognize a longitudinal position. These structures have highly distinctive reflectivity from the surrounding walls, which can be distinguished using LIDAR reflectivity data. Furthermore, reflectivity information of tunnel walls was fused with the road surface reflectivity map to generate a synthetic reflectivity map. When the synthetic reflectivity map was used, localization of vehicles was able through correlation matching with the local maps generated from the current LIDAR data. The experiments were conducted at an expressway including Maseong Tunnel (approximately 1.5 km long). The experiment results showed that the root mean square (RMS) position errors in lateral and longitudinal directions were 0.19 m and 0.35 m, respectively, exhibiting precise localization accuracy.