• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.157-162
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• 2018

Tracking the location of patients in medical facilities is important to guarantee the patients' safety and to improve the service quality. Previous studies related to location tracking systems based on Bluetooth communication need numerous prerequisite information and multiple devices to improve the accuracy. In this paper, we propose a beacon-based space partition scheme that assigns different arrangement patterns of beacons to different spaces and composes groups with the similar value of RSSI to minimize prerequisite information and the number of beacons. The proposed scheme considers a pattern arrangement scheme to minimize intereference between neighbor patterns. We also verified the applicability of our scheme to monitor the patient location by using experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.605-612
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• 2008

This paper researches the estimating location using repeater effect adjustment method in CDMA based system. Repeaters are commonly used by commercial and amateur radio operators to extend signals in the radio frequency range from one receiver to another. The repeater signals are increasing arrival time from base station to mobile station. So if we calculates the mobile station using repeater signals, the estimating position error is increased. However nobody researched about adjusting repeater effects. This paper proposes repeater effect adjustment algorithm. For adjusting repeater effects, we make the triangle using mobile station, reference base station and neighbor base station, and then detect the repeater effects using the triangle characteristic. The proposed method system showed the improved performance in estimating parameters and locating positions by computer simulations.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.109-117
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• 2010

With the advent of new technologies such as HSDPA, WiBro(Wireless Broadband) and personal devices, we can access various contents and services anytime and anywhere. A location based service(LBS) is essential for providing personalized services with individual location information in ubiquitous computing environment. In this paper, we propose mapping algorithm for error compensation of indoor localization system. Also we explain filter and indoor localization system. we have developed mapping algorithms composed of a map recognition method and a position compensation method. The map recognition method achieves physical space recognition and map element relation extraction. We improved the accuracy of position searching. In addition, we reduced position errors using a dynamic scale factor.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.3
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• pp.87-94
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• 2006

For realizing an ubiquitous home network(uHome-net), various sensors should be able to be connected to an integrated wire/wireless sensor network. This paper describes an application case of applying LonWorks technology being widely used in control network to wire/wireless sensor network in uHome-net and the design and application of LonRF device that consists of a neuron chip including LonTalk protocol, a 433.92MHz RF transceiver, a sensor, and application programs. As an application example of the LonRF device, the LonRF smart badge that can measure the 3D location of objects in indoor environment and interwork with the uHome-net was developed. LonRF device based home network services were realized on the uHome-net testbed such as indoor positioning service, remote surveillance service and remote metering service were realized. This research shows that LonWorks technology based sensor network could be applicable to the control network in an ubiquitous home network and the LonRF device can be used as a wireless node in various sensor networks.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.66-77
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• 2006

In this paper, we researched the searching and tracking locations of a home resident using ON/OFF switches and sensors and designed a remote monitoring system. As an implementation environment, this system is developed on the base of the distributed object group framework we have developed from previous works. In order to trace the moving locations of a home resident, we firstly showed a home structure which attaches ON/OFF switches and sensors to home appliances and indoor facilities being fixed in home. Whenever a home resident opens/closes these objects, the signals operated from ON/OFF switches and sensors are sent to a home server system. In this time, the real locations of ON/OFF switches and sensors that the signals are being occurred must be the current location that he/she stays. A home server system provides the functionalities that map the real location of a resident in home to virtual location designed on remote desk-tops or terminals like PDAs, and that construct a healthcare database consisted of moving patterns, moving ranges, momentum for analyzing the given searching locations and times Finally, this system provides these information for remotely monitoring services.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.33-42
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• 2016

In Korea, the address-point matching technique has been used to provide geocoding services. In fact, this technique brings the high positional accuracy. However, the quality of geocoding result can be limited, since it is significantly affected by data quality. Also, it cannot be used for the 3D address geocoding and the reverse geocoding. In order to alleviate issues, the paper has implemeted proposed geocoding methods, based on street-based addresses matching technique developed by US census bureau, for street-based addresses in Korea. Those proposed geocoding methods are illustrated in two ways; (1) street address-matching method, which of being used for not only 2D addresses representing a single building but also 3D addresses representing indoor space or underground building, and (2) reverse geocoding method, whichas converting a location point to a readable address. The result of street-based address geocoding shows 82.63% match rates, while the result of reverse geocoding shows 98.5% match rates within approximately 1.7(m) the average position error. According to the results, we could conclude that the proposed geocoding techniques enable to provide the LBS(Location Based Service). To develop the geocoding methods, the study has perfoermed by ignoring the parsing algorithms for address standardization as well as the several areas with unusual addresses, such as sub-urban areas or subordinate areas to the roads, etc. In the future, we are planning the improved geocoding methods for considering these cases.

• Journal of Korea Multimedia Society
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• v.12 no.1
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• pp.156-167
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• 2009

Computing environment is evolving rapidly to ubiquitous environment. It thus makes people access and utilize any resource on the move and makes location of objects rise to the rank of the most important information. However provision of location information is too restrictive in small environments such as a home or building. In this paper we propose a home entertainment system which supports user mobility based on sensor networks and distributed devices. The proposed system estimates a user location by using signal strength received from Bluetooth ad-hoc networks. This estimated location information can tell which device a user can take advantage of while moving. In order to prove possibility of user mobility support, the system is implemented on our UPnP A/V framework home entertainment system to provide content streaming and the result shows that a provision of service for mobile users could be possible in small ubiquitous computing environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2677-2682
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• 2015

Smart factory has the function of integrated management of production process management, logistics management as a intelligent factory, it is also emerging as the core of new industry which converges ICT and manufacturing business. We suggested Smart factory logistics management system which embedded position tracking technology and the system converges ICT and IoT. This suggested system can manage all the processes from production to release by tracking route and position based on signal strength of bluetooth 4.0 beacon tag. For the more, we will expect to apply to the various type of factory environments like detachable installation, optimized management using sensor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.4
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• pp.315-325
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• 2014

In ubiquitous environment, User's location information is very important to serve personalized service to user. Previous works consider only User's locations in the big buildings and assume APs are fixed. Normal home environment, However, is consists of small spaces. And the state of APs is highly fluid. Previous research has focused on indoor localization in the building where has stationary AP environment. However, in this paper, we propose as User's Location Predicting System that finds out a space where a user is located based on Wi-Fi Fingerprint approach in home environments. The results that conducted real home environments are using the system show more than 80% accuracy.