• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.207-210
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• 2017

가시광 통신 환경 내에서 사용자가 데이터를 받을 때, 공격자가 도청하는 위치는 특정할 수 없다. 공격자는 특정되지 않은 위치에서 다양한 행위를 할 수 있다. 공격자는 조명 그 자체를 관측하여 유의미한 데이터를 얻을 수도 있고, 사용자의 근처에서 사용자와 같은 데이터를 얻을 수도 있다. 이와 같은 도청 행위를 방지하기 위해서 암호화가 필요하다. 본 연구에서는 사용자의 통신에 지장을 주지 않는 물리계층 암호화 방법을 제안한다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2345-2347
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• 2001

본 연구에서는 반도체형으로 생산된 가속도센서를 적용하여 거리를 측정하는데 있어 문제점에 대해 언급하고, bias drift error에 따른 적분 누적오차를 줄이기 위한 방법으로 random noise를 감소시키고 위치추정을 위한 데이터 융합에 가장 일반적으로 적용되는 Kalman Filter 알고리즘을 적용하여 가속도 데이터를 상대적 위치 데이터로 변환하여 거리측정에 적용하였다. 또한 가속도센서를 관절형 로봇에 부착시켜 실험하여 이동거리를 산출하는 실험을 수행하였다. 실험 결과 보상 알고리즘을 사용했을 때의 zero drift error과 누적오차가 감소됨을 알 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.498-500
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• 2015

본 논문에서는 가속 센서의 데이터로부터 얻은 정보를 특정 알고리즘을 통해 3D 공간상에서 좌표를 매핑(Mapping)하는 3D 마우스를 제안한다. 손의 움직임에 따라 변화하는 가속도 값을 블루투스 통신을 사용하여 모바일 디바이스(Mobile Device)로 전송한다. 본 논문에서 제안하는 3D 마우스는 손에 든 가속도 센서 데이터를 사용하여 손이 움직이기 전의 위치를 기준으로 가속도 데이터를 토대로 움직인 후의 위치를 추출하여 3D 공간 상에서의 마우스를 구현하였다. 10명의 사용자에게 마우스를 동일한 시작점에서 정해진 목표지점까지 움직이도록 실험해 본 결과 평균 2.23번 만에 성공하였다.

• KIISE Transactions on Computing Practices
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• v.22 no.3
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• pp.145-150
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• 2016

Finding the exact location of faults in a program requires enormous time and effort. Several fault localization methods based on control flows of a program have been studied for decades. Unfortunately, these methods are not applicable to programs based on data-flow languages. A recently proposed mutation-based fault localization method is applicable to data-flow languages, as well as control-flow languages. However, there are no studies on the effectiveness of the mutation-based fault localization method for data-flow based programs. In this paper, we provided an experimental case study to evaluate the effectiveness of mutation-based fault localization on programs implemented in Function Block Diagram (FBD), a widely used data-flow based language in safety-critical systems implementation. We analyzed several real faults in the implementation of FBD programs of a nuclear reactor protection system, and evaluated the mutation-based fault localization effectiveness for each fault.

• Journal of Intelligence and Information Systems
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• v.12 no.3
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• pp.83-93
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• 2006

This paper is wireless location awareness technology using RFID. We investigates the Location of the received Signal strength reported by RF Analyses of the data are performed to understand the underlying features of location fingerprints. The system is performed factors the extreme environmental Emit signal, which consists of a unique 5000 Terminals. The Location Service have become very popular in many service industries, purchasing and distribution logistics, industry, manufacturing companies and a parking place. The Technically optimal Solution would be the storage of Intelligence information in the most common form of electronic data-carrying device in use in everyday life is the smart card based upon a contact field (telephone smart card, bank cards). The method of an indoor positioning experiment system is compared using measured Location data and a charge of service. The result of research showed the following: first, to check out the mechanism between benefit of system installation and operation of Active RFID. Second, it contributed on indoor wireless location intelligence system efficiency.

• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.322-329
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• 2009

Many researches in wireless sensor networks have used a geographic routing to effectively disseminate data between sinks and sources. To know the location information, the geographic routing has proposed two manners. A sink-initiated and a source-initiated are flooding to disseminate its location information in WSN. However, these two manners have two problems. Firstly, whenever they move, they flood their location information. Secondly, their location information is disseminated unnecessary nodes besides nodes which send and receive data in actually. Therefore, this paper proposes a protocol that can solve the two problems and disseminate effectively data between few sinks and few sources. The proposed protocol exploits a location information manager that manages location information of the sinks and the sources. We also compare the performance of the proposed protocol with the existing protocols through a simulation.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.89-96
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• 2015

Location-based social media data have high potential to be used in various area such as big data, location based services and so on. In this study, we applied a series of analysis methodology to figure out how the important keywords in location-based social media are spatially distributed by analyzing text information. For this purpose, we collected tweet data with geo-tag in Gangnam district and its environs in Seoul for a month of August 2013. From this tweet data, principle keywords are extracted. Among these, keywords of three categories such as food, entertainment and work and study are selected and classified by category. The spatial clustering is conducted to the tweet data which contains keywords in each category. Clusters of each category are compared with buildings and benchmark POIs in the same position. As a result of comparison, clusters of food category showed high consistency with commercial areas of large scale. Clusters of entertainment category corresponded with theaters and sports complex. Clusters of work and study showed high consistency with areas where private institutes and office buildings are concentrated.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1515-1526
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• 2022

Image-based 3D reconstruction is to restore the shape and color of real-world objects, and image sensors mounted on mobile platforms are used for positioning and mapping purposes in indoor and outdoor environments. Due to the increase in accidents in underground space, the location accuracy problem of underground spatial information has been raised. Image-based location estimation studies have been conducted with the advantage of being able to determine the 3D location and simultaneously identify internal damage from image data acquired from the inside of pipeline-type underground facilities. In this study, we studied 3D reconstruction based on the images acquired inside the pipe-type underground facility and reference data. An unmanned mobile system equipped with a stereo camera was used to acquire data and image data within a pipe-type underground facility where reference data were placed at the entrance and exit. Using the acquired image and reference data, the pipe-type underground facility is reconstructed to a geo-referenced 3D shape. The accuracy of the 3D reconstruction result was verified by location and length. It was confirmed that the location was determined with an accuracy of 20 to 60 cm and the length was estimated with an accuracy of about 20 cm. Using the image-based 3D reconstruction method, the position and line-shape of the pipe-type underground facility will be effectively updated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.61-69
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• 2006

Position determination accuracy is strongly depending on how much precisely and frequently satellite receiver measures transmitted signals from terminals on target animals when Doppler effect is applied for position determination. ARGOS satellite system has shown relatively high position determination accuracy by operating multiple satellites, which enable operator to get more Doppler shift data from terminals. In case of animal tracking mission with single satellite, however, it is difficult for the satellite receiver to receive transmitted signals from terminals frequently during short period that satellite passes over ground terminals. This is one of the main sources to decrease position accuracy on target animals. In this paper, the Doppler rate estimation is implemented to increase the number of Doppler shift data received by single satellite. It is proved that the relatively high position determination accuracy with increased number of estimated data can be obtained. We also suggest that the Doppler rate estimation is applicable for position determination system with single satellite.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1305-1310
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• 2007

ePosition is a technology that can provide the spacial position of the earth to the information of ePosition ID through the Internet. It is serving the information of land location based on the Internet using the ePosition technology now, but it needs the service technique which can supply the marine data and the information of maritime position. Moreover, to support the information service of marine position, it needs the ENC linked technique based on S-57 that is an IHO transfer standard for digital hydrographic data. In this paper, therefore, it develops a linkage method for applying and utilizing the ePosition technology to ENC data, and supplements the base technology for applying it to marine related fields. As study method, firstly, this paper analyses ENC data model and structure, and converses for processing ENC file to ePosition data. Lastly, it derives the interconnection method with ePosition database and shows the ePosition service application based on the linked data and its validity.