• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.117-128
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• 2013

u-safety service system inter-works with the diverse operation agencies, through CCTV network, such as the emergency call terminal with built-in GPS, the mobile communication network, u-safety service provider, relay system and CCTV control center. In the case of the emergency call, this service searches the location of caller in real time, and then continues to search the location of caller through the control of CCTV in the searched place, and can provide the several agencies like guardian, police office, fire station, hospitals, relief organizations and municipalities, with the diverse information necessary for the secure rescue through SMS and wired network. In this paper, a new protocol and specification for u-safety service relay system is designed and implemented. The effectiveness of presented protocol is verified by computer simulation. The designed protocol of u-safety service is applied to real 3GPP and 3GPP2 mobile communication networks to verify its performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.10
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• pp.40-45
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• 2009

In this paper, we introduce a mobile-type tiny sensor device that can classify the activities of daily living based on the state-dependent motion analysis using a 3-axial accelerometer in real-time. The device consists of an accelerometer, GPS module, 32bit micro-controller for sensor data processing and activity classification, and a bluetooth module for wireless data communication. The size of device is 50*47*14(mm) and lasts about 10 hours in operation-mode and 160 hours in stand-by mode. Up to now, the device can recognize three user activities ("Upright", "Running", "Walking") based on the decision tree. This tree is constructed by the pre-learning process to activities of subjects. The accuracy rate of recognizing activities is over 90% for various subjects.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.2
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• pp.39-47
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• 2017

Although motorcycle safety studies to date have identified the causes of motorcycle accidents in general, very few have investigated postal motorcycle accidents by studying the delivery postmen's specific work environment. To better understand postal motorcyclists' driving behavior associated with their delivery workload, we developed a system using V-World platform which visualizes driving behavior in real time along the driver's delivery route throughout an entire work day. We conducted a field test to examine the feasibility of our system by involving six delivery postmen currently working in Songpa, Seocheongju, and Gangseo, respectively. To show the potential of our system for nationwide comparison of postal motorcyclists' driving behavior and their workloads, we present several sample analyses using the collected field data. Although ideally, postmen's workloads should be standardized nationwide, we found large variation depending on regional characteristics of work area which affects postmen's driving behavior.

• Journal of Information Technology Services
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• v.16 no.2
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• pp.111-127
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• 2017

Computing Performance, sensor, storage, memory, and network costs have been steadily declining, and IoT services have recently become more active. The Internet of Things is linked with Big Data to create new business, and public institutions and corporations are hurry to import Internet of things. As the importance of the Internet of things has increased, the number of devices supporting the IoT has rapidly increased. With the development of the Internet of Things, various types of Internet services are being developed. For this reason, there is an increasing demand for IoT service designers and developers for IoT service case automatic search technology. IoT service designers can avoid duplication with existing services through service case retrieval and developers can save cost and time by combining existing reusable service equipment. This paper proposes IoT-Lite ontology for IoT and Semantic Web service to solve the above-mentioned problems. The existing ontologies for IoT, despite its many advantages, are not widely used by developers because it has not overcome the relatively slow drawbacks of increasing complexity and searching for development. To complement this, this study uses the IoT-Lite ontology introduced by W3C as a model and a semantic web service for automatic system retrieval. 3D camera, GPS, and 9-axis sensor, and IoT-Lite designed by IoT-Lite technique are integrated with the semantic technique and implemented directly.

• Journal of Korean Society of Transportation
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• v.32 no.5
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• pp.452-461
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• 2014

Conventional parking survey has been usually performed by a person, which has a lot of problems such as decreased mobility, data input error, longer time and expensiveness. Therefore, this study attempted to develop an automatic parking survey method using lately commercialized equipments that were highly efficient imagery interpretation equipments, GPS, and infrared lighting fixtures. In addition, this study developed a parking analysis software that enables to modify and save data, and analyze survey data by the automatic parking survey method. When parking survey is conducted using automatic parking survey method, surveying accuracy is influenced by the running speed of a surveying vehicle, the photographing angle of an imagery interpretation equipment, the gap between parking vehicles and the distance of a surveying vehicle to parking vehicles. Therefore, this study drew optimum conditions by testing on each items for accuracy improvement, and developed a parking analysis software for systematic storage and management of parking survey data, supporting the parking analysis and output the parking analysis result.

• Journal of Internet Computing and Services
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• v.9 no.4
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• pp.51-59
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• 2008

In wireless sensor networks, one of most common location detection methods that do not require additional devices such as GPS and ultrasonic sensor, is the location detection method based on received signal strength. However, measured received signal strength will fluctuate over time mainly due to physical radio channel characteristics between nodes, which subsequently will cause errors to measured distance between nodes. Since these contaminated distance data are utilized to detect the location of unknown node, there will be accumulated errors in the location of unknown node. In order to overcome the limitation of the location detection method based on received signal strength, we propose a location scheme in which reliability information of distance data as well as distance data between nodes are utilized to estimate the location of unknown node. Through simulation, it is shown that the proposed scheme can accomplish 30% capacity improvement.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.301-306
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• 2010

Recently GIS is not only displaying and servicing data on the 2D, but also is changing rapidly to display and service 3D data. Also 3D related technology is developing actively. For display of 3D data, terrain DTM has become a basis. Generally, to acquire DTM, users are using LIDAR data or digital map's contour line. However, if using these data for producing DTM, users need to additional cost and data lead time. And hard to update terrain data. For possibility of solving these problem, this study did DTM extraction with automatic matching for aerial photograph, and analysed the result with measurement of Orthometric height and excuted accuracy through DTM(which extracted from digital photogrammetric technique). As a result, we can get a high accuracy of RMSE (0.215m).

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.13-20
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• 2010

Currently, NGII(National Geographic Information Institute) provides VRS(Virtual Reference System) service using 44 CORS(Continuously Operating Reference Stations). Since the VRS provides high-precision coordinate in a short time, the users and applications are expected to be rapidly increasing. The accuracy analysis on the VRS service, however, was not sufficiently performed yet. Therefore, in this study, the VRS data is acquired from various circumstances and its accuracy is analyzed. According to analysis, it was concluded that the VRS could be applied to public control point survey. Furthermore, it was found that the PQ(Position Quality) which represents variance of estimated coordinates rather than GDOP(Geometric Dilution of Precision) is more relevant as a factor to determine the accuracy of coordinates. Based on the analysis of data from four manufacturers (TRIMBLE, MAGELLAN, LECIA, TOPCON), it was confirmed that the standard deviations better than 3cm. Therefore, VRS Survey apply to public control point survey.

• Korean Journal of Remote Sensing
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• v.34 no.1
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• pp.101-115
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• 2018

The Long Valley area and its surroundings are part of a major volcano system where inflation occurred in the resurgent dome in the 1990s. We used ENVISAT data to monitor surface deformation of the Long Valley area and its surroundings after the inflation, from 2003-2010. To retrieve the time series of the deformation, we applied the refined Small BAseline Subset (SBAS) algorithm which is improved using an iterative approach to minimize unwrapping error. Moreover, ascending and descending data were used to decompose the horizontal and vertical deformation in detail. To confirm refined SBAS results, we used GPS dataset. The InSAR errors are estimated as ${\pm}1.0mm/yr$ and ${\pm}0.8mm/yr$ from ascending and descending tracks, respectively. Compare to the previous study of 1990s over the Long Valley and its surroundings, Paoha Island and CASA geothermal area still subside. The deformation pattern in the Long Valley area during the study period (2003-2010) went through both subsidence (2003-2007) and slow uplift(2007-2010) episodes. Our research also shows no deformation signal near McGee Creek. Our study provided a better understanding of the surface changes of the indicators in the 1990s and 2000s.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.257-263
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• 2012

Smart phones become popular all over the world recently. At the same time, demand of various additional services, such as SNS by utilizing low-cost reliable Wi-Fi network and position information, is expected to keep growing. In this paper, Implementation of SNS based on an Open Wi-Fi & Position Information was proposed. This service is achieved by constructing an Open Wi-Fi network based on a built AP access information database. And in order to provide durable connection in mobile environment, RSS detect AP switching module and mobile IP are utilized in the proposed service. Furthermore, with the utilization of GPS information of AP, AP providers could delivery various information such as advertisements, promotion events. In addition, it is possible for AP users to communicate with each other, thus a position information based SNS was also proposed in this paper.