• Journal of Digital Convergence
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• v.11 no.4
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• pp.243-249
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• 2013

In this paper, GPS(Global Positioning System) that can be used outdoors and GPS(Global Positioning System) is not available for indoor Wi-Fi(Wireless Fidelity) using the Android-based location information system has been designed and implemented. Pedestrians in a room in order to estimate the location of the pedestrian's position, regardless of need to obtain the absolute position and relative position, depending on the movement of pedestrians in a row it is necessary to estimate. In order to estimate the initial position of the pedestrian Wi-Fi Fingerprinting was used. Most existing Wi-Fi Fingerprinting position error small WKNN(Weighted K Nearest Neighbor) algorithm shortcoming EWKNN (Enhanced Weighted K Nearest Neighbor) using the algorithm raised the accuracy of the position. And in order to estimate the relative position of the pedestrian, the smart phone is mounted on the IMUInertial Measurement Unit) because the use did not require additional equipment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.6
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• pp.531-539
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• 2013

Fingerprinting technique uses the radio signal strength measured reference locations is typically used, although there are many Wi-Fi based location tracking techniques. However, it needs numerous reference locations for precision and accuracy. This paper the analyzes problems of previous techniques and proposes a fingerprinting system using reliability based on a signal strength map. The system collects the signal strength data from a number of reference locations designated by the developer. And then it generates path-loss models to one of the access points for each reference location. These models calculate the predicted signal strength and reliability for a lattice. To evaluate proposed method and system performance, We perform experiments in a $20m{\times}22m$ real indoor environment installed access points. According to the result, the proposed system reduced distance error than RADAR. Comparing the existing system, it reduced about 1.74m.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.3
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• pp.46-56
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• 2001

The present study concerns the numerical simulation of a supply airflow control in a variable air volume (VAY) system. A stratified thermal model (multi-zone model) is suggested to predict a local thermal response of an air-conditioned space. The effects of various thermal parameters such as the cooling system capacity, the thermal mass of an air-conditioned space, the time delay of thermal effect, and the building envelope heat transmission are investigated. Further, the influence of control parameters such as the supply air temperature, the PI control factor and the thermostat location on a VAV system is quantitatively delineated. The results obtained show that the previous homogeneous lumped thermal model (single zone model) may overestimate the time taken to the set point temperature. It is also found that there exist the appropriate ranges of the control parameters for the optimal airflow control of the VAV system.

• Journal of the Korea Society of Computer and Information
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• v.24 no.7
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• pp.93-100
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• 2019

In this paper, we propose an intelligent marketing service system that can provide custom advertisements and events to both businesses and customers by identifying the location and contents using the ultrasonic signals and feature information in voice signals. We also develop the encoding and decoding algorithm of ultrasonic signals for this system and analyze the performance evaluation results. With the development of the hyper-connected society, the on-line marketing has been activated and is growing in size. Existing store marketing applications have disadvantages that customers have to find out events or promotional materials that the headquarters or stores throughusing the corresponding applications whenever they visit them. To solve these problems, there are attempts to create intelligent marketing tools using GPS technology and voice recognition technology. However, this approach has difficulties in technology development due to accuracy of location and speed of comparison and retrieval of voice recognition technology, and marketing services for customer relation are also much simplified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1376-1383
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• 2020

Although studies on fire evacuation systems are increasing, studies on the evacuation of evacuees in indoor spaces are insufficient. According to the latest research, it has been suggested that the use of high frequency might be effective for identifying the location of evacuees indoors. Accordingly, in this paper, the authors intend to develop evacuation location recognition technology and fire evacuation guidance system using high-frequency and a smartphone. The entire system was developed, including an app server, evacuees location recognition unit, an evacuation route search, an output unit, and a speaker unit based on Wi-Fi communication. The experimental results proved the possibility of the effectiveness of the system in the fire situation data. It is expected that this study could be used as an essential study of a fire evacuation guidance system using high frequency data in case of fire.

• Journal of KIBIM
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• v.6 no.3
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• pp.15-23
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• 2016

The purpose of this study is to present the possibility of adopting beacons to implement the fire evacuation guidance system in order to reduce the evacuation time for a fire in complex buildings. A beacon-based evacuation system can quickly detect a fire's origin, optimal path of evacuation involved with the exits and the location of evacuees using information collected by the proposed system. The assessment is conducted by integrating different scenario models including fire simulation. Based on the research result, beacon is an effective tool to warn potential hazards or to provide early detection and a safe escape.

• Journal of the Korea Safety Management & Science
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• v.14 no.4
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• pp.117-123
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• 2012

For an effective energy management in intelligent buildings it is necessary to gather information about position/absence of people and the level of population. In this paper the smart occupancy detection system using the active RFID is developed to satisfy such a demand based on the results of previous research. First of all the design considerations and functions of the system are introduced. In sequence the functions of the system is presented, and then the performance of the developed system is tested and verified through various field tests. The developed core technology can be also applied to other fields such as security, healthcare, smart home, etc.

• Journal of IKEEE
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• v.15 no.1
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• pp.76-85
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• 2011

In this paper, we analysed RSS characteristics by external factors and presented an efficient algorithm for real-time location tracking and its hardware system. The proposed algorithm enhanced the ranging accuracy using Kalman Filter based on the RSS DB. The location tracking system that consists of the tag, AP(Access Point), a data collector(Data Receiver) with IEEE 802.15.4(ZigBee) network environment, and location tracking application that reveal locations of each tag is implemented for the test environment. The location tracking system presented in this paper is implemented with MSP430 microprocessor manufactured by TI(Texas Instrument), CC2420 RF chipset and the location tracking application. With the results of the experiment, the proposed algorithm and the system can achieve the efficiency and the accuracy of location tracking with the average error of 19.12cm, and its standard deviation of 5.31cm in outdoor circumstance. Also, the experimental result shows that exact tracking of position in indoor circumstance cannot achieve because of vulnerable RSS with external circumstance.

• Journal of the Korean Professional Engineers Association
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• v.41 no.5
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• pp.55-58
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• 2008

GPS is the global Navigation Satellite System which is developed by the United States Department of Defense as an abbreviation of the Global Positioning System. The GPS uses a constellation of 24 Medium Earth Orbit satellites that transmit precise microwave signals, that enable GPS receivers to determine their location, speed, direction, and time. Following, the shooting down of Korean Air Lines Flight 007 in 1983. President Ronald Reagan issued a directive making the system available free for civilian use as a common good. Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, scientific uses, and hobbies such as geocaching. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.87-95
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• 2016

Recently, the interests of the precise localization are rapidly increasing, which are linked to IoT(Internet of Things) sensors. The precise localization in indoor environment can be utilized in navigation, security, anti-collision, and various location based services etc. However, conventional positioning sensors, such as PIR, ultrasonic, microwave etc. are vulnerable to weather or insensitive to direction of subject movement or low precision performance. In this paper we implement a UWB-IR localization system for long distance and high-precision localization, which is not affected by temperature, light and weather. The proposed system was divided and designed by H/W, Antenna, S/W parts, each of which was designed based on an accurate analysis and simulation. As a result, we can implemented and verified UWB IR system with precise localization performance.