• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.475-478
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• 2006

본 논문에서는 소형 무인항공기의 정확한 위치, 속도, 자세 정보를 제공하기 위해 저급의 MEMS IMU를 이용한 항법 시스템을 제안한다. 제안하는 시스템은 비행체의 직선운동과 회전운동을 측정할 수 있는 관성측정기와 위성신호를 수신하여 항체의 위치, 속도 정보를 제공하는 GPS 수신기, 지구 자기장 정보를 이용하여 방향각 정보를 제공하는 지자기 센서들로 구성되었다. SDINS와 약결합 방식의 칼만필터를 이용한 항법 시스템은 초기정렬 알고리즘과 센서 오차 보상 알고리즘, 자력계 보상 알고리즘 및 복합항법 알고리즘으로 나뉘며, 설계된 항법 알고리즘들은 시뮬레이션과 차량 실험을 통해서 성능을 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.843-845
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• 2012

전기자동차 또는 로봇의 자율 주행에 필요한 여러 가지 기술 가운데 위치 인식과 진행 방향을 결정하는 외부 환경인지 능력은 매우 중요하다. 본 논문에서는 GPS 수신 장치와 각종센서를 내장한 안드로이드 폰을 활용하여 자율 운행 중인 골프카트의 위치 정보를 획득하고 도로이탈 여부를 판별할 수 있는 시뮬레이션 시스템을 개발한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.1330-1332
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• 2012

휴대전화에 인터넷 통신과 정보검색 등 컴퓨터 지원 기능을 추가한 스마트폰이라 불리는 지능형 단말기가 등장하여 우리의 일상생활에 깊이 관여하고 생활의 패턴을 바꾸는 큰 변화를 불러왔다. 현재 음식추천 어플리케이션들은 대부분 주변의 음식점의 위치나 메뉴 정보 등을 제공하고 있다. 본 논문에서는 음식 추천방식에 룰렛을 이용하여 게임 형식의 음식추천이 가능하게 하였으며 구글 맵 기능을 활용하여 현재위치에서 내가 찾는 음식점 중에 반경을 입력하면 그 반경 안에 있는 음식점들을 검색하도록 Android 운영체제를 기반으로 한 어플리케이션을 개발하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.176-179
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• 2013

본 연구는 최근 활성화된 스마트폰 내비게이션의 교통정보를 이용 시 상대적으로 품질이 취약한 지방지역의 빠른길 및 통행시간 정확도를 개선하는 방안에 대한 연구이다. 본 연구에서는 Hadoop기술을 이용하여 교통데이터에 대한 방대한 양의 데이터를 분석 처리한다. 특히, 실시간 교통정보가 제대로 수집되지 않는 지역의 도로 속도 정보에 대한 개선 방안으로 고객 단말로부터 올라오는 위치 데이터를 실시간으로 수집하여 전자지도 기본 속성값을 실시간 통계 데이터로 교체 반영하여 상대적으로 취약한 지방지역의 경로 품질 및 경로 탐색을 개선하는 방안을 제시하였다. 단말로부터 올라오는 많은 양의 GPS 위치정보등 대용량 데이터 처리를 위해 오픈소스프로젝트인 Hadoop플랫폼 환경에서 빅데이터 처리용 오픈소스를 활용하여 고가의 RDBMS를 대체하는 효과와 시간 단축의 효과를 기대할 수 있게 되었다.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.271-281
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• 2006

Recently the need for Location-Based Service (LBS) has increased due to the development and widespread use of the mobile devices (e.g., PDAs, cellular phones, labtop computers, GPS, and RFID etc). The core technology of LBS is a moving-objects database that stores and manages the positions of moving objects. To search for information quickly, the database needs to contain an index that supports both real-time position tracking and management of large numbers of updates. As a result, the index requires a structure operating in the main memory for real-time processing and requires a technique to migrate part of the index from the main memory to disk storage (or from disk storage to the main memory) to manage large volumes of data. To satisfy these requirements, this paper suggests a unified index scheme unifying the main memory and the disk as well as migration policies for migrating part of the index from the memory to the disk during a restriction in memory space. Migration policy determines a group of nodes, called the migration subtree, and migrates the group as a unit to reduce disk I/O. This method takes advantage of bulk operations and dynamic clustering. The unified index is created by applying various migration policies. This paper measures and compares the performance of the migration policies using experimental evaluation.

• Journal of Internet Computing and Services
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• v.15 no.6
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• pp.27-34
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• 2014

Todays, the rapid technical progress of smart device has been used for various social (wall-fare) services in our lives. Especially, most of these services are based on the Local-based Services (LBS) and this technology is getting popular more and more compared with before. Basically, LBS is able to support various types of geographical services such as vehicles' navigation services, Augmented reality services as using extensional local information such as GPS. However, LBS has serious mathematical vulnerability on the services frequently because of its miscalculated GPS data under interior and ambiguous geographical environment such like shadowed area. So, to overcome this limitation, iBeacon, which would be able to mitigate LBS miscalculation process, has been proposed recently among network experts. Compared with other wireless technologies, iBeacon is able to determine the accurate geographical data of certain local positions easily because it is not only designed based on low-powered data transmitting technology, but also, it can be much easy to be deployed. As users' dependency of smart devices are getting higher and higher and the use of smart device is also getting complex more and more, the users prefer to use various types of smart devices at one time. Therefore, in this paper, we propose the loss prevention system that is able to interwork smart devices networks as using iBeacon technology for users' better conveniences.

• The Journal of Society for e-Business Studies
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• v.21 no.3
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• pp.15-28
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• 2016

This paper proposes a system recommending spatial information what user wants with collecting and analyzing tweets around the user's location by using the GPS information acquired in mobile. This system has built an emotion dictionary and then derive the recommendation score of morphological analyzed tweets to provide not just simple information but recommendation through the emotion analysis information. The system also calculates distance between the recommended tweets and user's latitude-longitude coordinates and the results showed the close order. This paper evaluates the result of the emotion analysis in a total of 10 areas with two keyword 'Restaurants' and 'Performance.' In the result, the number of tweets containing the words positive or negative are 122 of the total 210. In addition, 65 tweets classified as positive or negative by analyzing emotions after a morphological analysis and only 46 tweets contained the meaning of the positive or negative actually. This result shows the system detected tweets containing the emotional element with recall of 38% and performed emotion analysis with precision of 71%.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.800-808
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• 2008

This paper presents a localization algorithm of the outdoor wheeled mobile robot using the sensor fusion method based on indirect Kalman filter(IKF). The wheeled mobile robot considered with in this paper is approximated to the two wheeled mobile robot. The mobile robot has the IMU and encoder sensor for inertia positioning system and GPS. Because the IMU and encoder sensor have bias errors, divergence of the estimated position from the measured data can occur when the mobile robot moves for a long time. Because of many natural and artificial conditions (i.e. atmosphere or GPS body itself), GPS has the maximum error about $10{\sim}20m$ when the mobile robot moves for a short time. Thus, the fusion algorithm of IMU, encoder sensor and GPS is needed. For the sensor fusion algorithm, we use IKF that estimates the errors of the position of the mobile robot. IKF proposed in this paper can be used other autonomous agents (i.e. UAV, UGV) because IKF in this paper use the position errors of the mobile robot. We can show the stability of the proposed sensor fusion method, using the fact that the covariance of error state of the IKF is bounded. To evaluate the performance of proposed algorithm, simulation and experimental results of IKF for the position(x-axis position, y-axis position, and yaw angle) of the outdoor wheeled mobile robot are presented.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.52-60
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• 2010

It is generally important to get a precise position information for autonomous unmanned vehicle(AUV) to run safely. For getting the position of AUV, the GPS has been using to navigation in a vehicle. Though it is useful to finding a position, it is difficult to precisely control a trajectory of the AUV due to large measuring error which may reach over 10 meters. Therefore to apply AUV it needs to compensate for the error. This paper proposes a method to more precisely localize AUV using three low-cost differential global positioning systems (DGPS). The distance errors between each DGPS are minimized as using the least square method (LSM) and the Kalman filter to eliminate a Gaussian white noise. The selected DGPS is cheaper and easier to set up than the RTK-GPS. It is also more precise than the general GPS. The proposed method can compensate the relatively position error according to stationary and moving distance of the AUV. For evaluating the algorithm by simulation, the DGPS signal with the Gaussian white noise to any points is generated by the AR model and compared with the measurement signal. It is confirmed that the proposed method can effectively compensate the position error as comparing with the measurement signal. The compensated position signal can be used to localize and control the AUV in the road.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.709-718
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• 2021

In this paper, it can be seen that the number of abandoned dogs increases every year through the statistics on the occurrence of abandoned animals. With the goal of reducing the number of stray dogs, a smart pet dog shoulder strap is implemented based on a real-time location tracking system using the ESP32 module and GPS sensor. It is an ESP32 module with a built-in Bluetooth module. It is input to the MCU using various sensors, and finally outputs to a smart-phone application, and communicates through the built-in blue-tooth module. In addition, it uses Neopixels to compensate the weaknesses at night through LED light emission, and automatically sets the warning distance to design a music playback system through the LED flashing effect and MP3 module. In addition, a smart pet dog shoulder strap was designed to help pet dog health care by measuring the moving distance according to the amount of activity through the gyro sensor.