• Journal of KIISE
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• v.42 no.2
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• pp.264-271
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• 2015

The general way to use a triangulation method is based on PTMP communication between an object and wireless modules in an environment, which is established by more than three wireless modules, to recognize the location of an object. Thus, this method has a problem that the PTMP-based system can only be applied in an environment where the wireless infra is already established. In order to solve this problem, the PTP communication schemes have been proposed but they are insufficient to generalize because they lack specific verification. In this paper, problems of an existed location estimation algorithm based on PTP communication are analyzed, and we propose a location estimation algorithm of a fixed object that satisfyies the condition of a single receiver being substituted to multiple receivers. A location estimation system we designed and implemented using CSS wireless communication modules to evaluate the proposed algorithm. We verify, by experimental results, that the optimum moving interval for the location estimation is 3m in indoor environment of $10m{\times}16m{\times}1m$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.302-313
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• 2018

As the demand for indoor location recognition system has been rapidly increased in accordance with the increasing use of smart devices and the increasing use of augmented reality, indoor positioning systems(IPS) using BLE (Bluetooth Lower Energy) beacons and UWB (Ultra Wide Band) have been developed. In this paper, a positioning plate is generated by using trilateration technique based on BLE Beacon and using RSSI (Received Signal Strength Indicator). The resultant value is used to calculate the PDR-based coordinates using the positioning element of the Inertial Measurement Unit sensor, We propose a precise indoor positioning algorithm that combines RSSI and PDR technique. Based on the plate algorithm proposed in this paper, the experiment have done at large scale indoor sports arena and airport, and the results were successfully verified by 65% accuracy improvement with average 2.2m error.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.33-39
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• 2014

Domestic and international researches, about intelligent systems based on a variety of location recognitions using location information, have actively proceeded. The representative location recognition method based on PTMP(Point To Multi Point) communication uses TOA(Time Of Arrival) to calculate distances to a fixed node that you want to recognize a position. The method is used to obtain the fixed node location information from three nodes location information that is applied by the triangulation method. There are disadvantages, an infrastructure should be established at a specific space and the system established cost is needed, in the location recognition method based on the PTMP communication, In this paper, the ranging based PTP(Point To Point) location recognition method is proposed to revise the disadvantage of PTMP location recognition method. And then it is compared with PTMP communication location recognition to evaluate performance. In this way, PTMP and PTP communication location recognition systems based on ranging were constructed and tested in an indoor environment. Experiment results show that the proposed PTP location recognition method could be confirmed to improve accuracy more than 3 times when it was compared with the existed PTMP location recognition method.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1207-1212
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• 2008

The purpose of this study is to evaluate the location of the outlets in the mechanical ventilation system installed in apartment. We performed the numerical analysis to estimate the ventilation effectiveness and the indoor $CO_2$ concentration considering the occupants and the condition with inlet and outlet in each room. From the numerical results, modified location of the outlets is about 10% high than designed one with respect to the ventilation effectiveness when the occupants are not considered. But designed location of inlet and outlet in living room and kitchen is better than modified one with respect to the reduction of $CO_2$ concentration in the living room and kitchen with occupants. In case of our model, Air change per hour (0.7) is not enough to sustain the acceptable criteria of $CO_2$ concentration (1000ppm) in the room with the occupants

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.1-8
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• 2013

Wireless Visible Light Communication is the technology that enables communication using LED illumination Infrastructure instead of existing illumination such as incandescent lamp or fluorescent light. Because VLC uses light for communication, it has no problem of frequency permission and is harmless to human body. It is also possible to check the communication through eye. So VLC can be used as a supplement to the Radio Frequency communication, Infrared in indoor environment. So far, researchers on the LED Visible light communication have focused on the increasing transmission speed, transmission distance, modulation method. However, there is few research of main factors that influence on system performance. System performance has been mainly predicted through simulation. In this paper, I recognized that these factors such as outside light noise, obstacle, LED panel position or emitted angle have a great impact on wireless communication system. So I experimented VLC system by changing distance and position to discover location suitable for BER regulation.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.9-20
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• 2005

In this paper, we propose ubiTrack, a system which tracks users' location in indoor environments by employing infrared-based proximity method. Most of recently developed systems have focussed on performance and accuracy. For this reason, they adopted the idea of centralized management, which gathers all information in a main system to monitor users' location. However, these systems raise privacy concerns in ubiquitous computing environments where tons of sensors are seamlessly embedded into environments. In addition, centralized systems also need high computational power to support multiple users. The proposed ubiTrack is designed as a passive mobile architecture to relax privacy problems. Moreover, ubiTrack utilizes appropriate area as a unit to efficiently track users. To achieve this, ubiTrack overlaps each sensing area by utilizing the TDM (Time-Division Multiplexing) method. Additionally, ubiTrack exploits various filtering methods at each receiver and utilization module. The filtering methods minimize unexpected noise effect caused by external shock or intensity weakness of ID signal at the boundary of sensing area. ubiTrack can be applied not only to location-based applications but also to context-aware applications because of its associated module. This module is a part of middleware to support communication between heterogeneous applications or sensors in ubiquitous computing environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.551-560
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• 2011

Recently, There has been increasing concern about WLAN-based indoor positioning system. Most of the existing WLAN-based positioning systems use a fingerprinting method as a main approach. In the fingerprinting approach, the accuracy of the location of a mobile objects is proportional to the number of reference points. However, depending on the increasing number of reference points in the training phase, it requires more time and effort to create fingerprint database. To solve these problems, we propose the new indoor positioning algorithm that calculate the distance between a mobile objects and an AP using the information of surrounding environment WLAN based APs and applied the particle filter to the proposed algorithm in order to improve the accuracy of the estimated location in this paper. To implement this algorithm, at first environmental information database such as wall, iron door, glass door, partition etc. existing in the periphery of the AP should be established. The positioning use attenuation model and path loss model. Our experimental results with proposed algorithm are verified that the positioning accuracy was low but solved the problems with fingerprinting, compared with other positioning algorithms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.264-266
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• 2022

In order to apply the RNN model to the radio fingerprint-based indoor path generation technology, the data set must be continuous and sequential. However, Wi-Fi radio fingerprint data is not suitable as RNN data because continuity is not guaranteed as characteristic information about a specific location at the time of collection. Therefore, continuity information of sequential positions should be given. For this purpose, clustering is possible through classification of each region based on signal data. At this time, the continuity information between the clusters does not contain information on whether actual movement is possible due to the limitation of radio signals. Therefore, correlation information on whether movement between adjacent clusters is possible is required. In this paper, a deep learning network, a recurrent neural network (RNN) model, is used to predict the path of a moving object, and it reduces errors that may occur when predicting the path of an object by generating continuous location information for path generation in an indoor environment. We propose a method of giving correlation between clustering for generating an improved moving path that can avoid erroneous path prediction that cannot move on the predicted path.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.638-646
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• 2006

유비쿼터스 시대가 도래함에 따라 사회적으로 실내 위치 추적 시스템에 대한 관심이 증가되었다. 하지만 기존 실내 위치 추적 시스템은 실내 환경의 빈번한 변화에 능동적으로 대응하지 못하고, 실내 환경의 NLOS 특성으로 인하여 이동 객체의 정확한 위치 측정이 어려운 문제점이 있다. 본 연구의 목적은 앞으로 유비쿼터스 시대가 도래함에 따라 다양한 사용자의 요구를 만족시키기 위한 서비스를 제공하는데 필수 요소인 실내 이동 객체의 위치를 효과적으로 파악하고, 이동 객체의 위치 정확도를 향상시킨 환경 적응형 위치 추적시스템을 제안한다.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.610-618
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• 2011

For improved localization around the indoor/outdoor transit area of buildings, this paper proposes an efficient algorithm combining the measurements from the WLAN (Wireless Local Area Network) and the GPS (Global Positioning System) for. The proposed hybrid localization algorithm considers both multipath errors and NLOS (Non-Line-of-Sight) errors, which occur in most wireless localization systems. To detect and isolate multipath errors occurring in GPS measurements, the propose algorithm utilizes conventional multipath test statistics. To convert WLAN signal strength measurements to range estimates in the presence of NLOS errors, a simple and effective calibration algorithm is designed to compute conversion parameters. By selecting and combining the reliable GPS and WLAN measurements, the proposed hybrid localization algorithm provides more accurate location estimates. An experiment result demonstrates the performance of the proposed algorithm.