• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.593-600
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• 2014

Information supporting system which is based on real-time prediction of currents to be applicable to the sea trial test of ship is developed. In the system, the spatial distribution of currents at specific time and the trends of variability of currents occurring at specific sites are also given as valuable information for sea trial test of ship. In addition, the system has a capability to connect with a GPS which provides information including speed loss of the ship caused by currents on the way of voyage. With information from the sea trial test, the system is also capable of delivering optimum time and pathways by considering calculated speed loss of ship at specific time and its pathway. Having information described as above, the real-time current prediction system supports and provides functions of not only running the test in an efficient way but also providing valuable information which is encouraged to be used during the test by installing at the ship.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.203-209
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• 2016

Digital tourism is the digital support of the tourist experience before, during and after the tourist activity[1]. The GPS-enabled mobile phones provide location-based mobile applications such as tour guide and storytelling services. In this paper, we propose the smart tour guide service platform based on GIS and develop the mobile application to provide the smart tour guide service. The proposed smart tour guide service platform consists of CMS, the multi-modal navigation system, the tour attraction content creation and management system, the tour commodity creation and management system, the smart search system, and the user terminal. The smart tour guide application supports digital tourism in the pre-tour, during tour, and post-tour using the proposed smart tour guide service platform in the popular tourist attractions in Jeju.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.283-290
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• 2011

A Raman LIDAR system has been designed and constructed for quantitative measurement of water vapor mixing ratio. The comparison with commercial microwave radiometer and global navigation satellite system(GNSS) was performed for the precipitable water vapor(PWV) profile and total PWV. The result shows that the total GNSS-PWV and LIDAR-PWV have good correlation with each other. But, there is small difference between the two methods because of maximum measurement height in LIDAR and the GNSS method. There are some significant differences between Raman and MWR when the water vapor concentration changes quickly near the boundary layer or at the edge of a cloud. Finally we have decided that MWR cannot detect spatial changes but LIDAR can measure spatial changes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.165-170
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• 2015

The topic of this paper is the advanced absolute altitude determination for 3-D positioning using barometric altimeter and the reference station. Barometric altimeter does not provide absolute altitude because atmosphere pressure always varies over the time and geographical location. Also, since Global Navigation Satellites system such as GPS, GLONASS has geometric error, the altitude information is not available. It is the reason why we suggested the new method to improve the altitude accuracy. This paper shows 3-D positioning algorithm using absolute altitude determination method and evaluates the algorithm by real field tests. We used an accurate altitude from RTK system in Seoul as a reference data and acquired the differential value of pressure data between a reference station and a mobile station equipped in low cost barometric altimeter. In addition, the performance and advantage of the proposed method was evaluated by 3-D experiment analysis of PNS and CNS. We expect that the proposed method can expand 2-D positioning system 3-D position determination system simply and this 3-D position determination technique can be very useful for the workers in the field of fire-fighting and construction.

• Korean Journal of Remote Sensing
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• v.24 no.2
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• pp.153-164
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• 2008

According to the economic growth, many highways are constructed for increasing need of better life style. Especially roads and roadside facilities are used for accident prevention and offering mobility for drivers. For these purpose, roads and roadside facilities should be well maintained and managed. Now, many roads and roadside facilities are constructed in many areas. Because of traditional surveying method requires much time and surveying efforts, we designed and developed mobile mapping system for highway maintenance and management purpose using multi sensors. We tested our mobile mapping system and data management process. Using developed database, road managers can easily check the information of facility conditions, positions, and attributes. We are expecting low cost and efficient road maintenance process by using our system.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.409-417
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• 2013

Mu-communication board supported by multi-communication is designed with Atxmega 128A1 which is a low power energy consuming of 8-bit microcontroller. ATxmega128A1 microcontroller consists of 8 UART(Universal asynchronous receiver/transmitter) ports which can be setting appropriate user interface having command line interpreter(CLI) program with each port, 2 kbytes EEPROM, 128 kbytes flash memory, 8 kbytes SRAM. 8 URAT ports are used for the multi communication modem, GPS module, etc. and EEPROM is used for saving a configuration for program running, and flash memory of 128 kbytes is used for storing a Firm Ware, and 8 kbytes SRAM is used for stack, storing memory of global variables while program running. If we uses the hybrid communication of path optimization of VHF, TRS and CDMA to remote control AtoN(aid to navigation), it is able to remove the communication shadow area. Even though there is a shadow area for individual communication method, we can select an optimum communication method. The compatibility of data has been enhanced as using of same data frame per communication devices. For the test, 8640 of data has been collected from the each buoy during 30 days in every 5 minutes and the receiving rate of the data has shown more than 99.4 %.

• The KIPS Transactions:PartD
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• v.14D no.7
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• pp.707-718
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• 2007

Recently, much studies for providing mobile users with suitable and useful content services, LBS(Location Based Service) corresponding to the change of users' location, are actively going on. First and foremost, this is basically owing to the progress of location management technologies such as GPS, mobile communication technology and the spread of personal devices like PDA and the cellular phones. Besides, the research scope of LBS has been changed from vehicle tracking and navigation services to intelligent and personalized services considering the changing information of conditions or environment where the users' are located. For example, it inputs the information such as heavy traffic, pollution, and accidents. The query languages which effectively search the stored vehicle and environment information have been studied depending on the increase of the information utilization. However, most of existing moving object query languages are not enough to provide a recommendation service for a user, because they can not be tested and evaluated in real world and did not consider changed environment information. In order to retrieve not only a vehicle location and environment condition but also use them, we suggest a moving object query language for recommendation service and implement a moving object query process system for supporting a query language. It can process a nearest neighbor query for recommendation service which considers various attributes such as a vehicle's location and direction, environment information. It can be applied to location based service application which utilizes the recommended factors based on environmental conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.8
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• pp.663-673
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• 2013

The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalization of LBS is the accurate estimating position for mobile object. Focusing on IMU deployed in smart phone, we develop a hybrid positioning estimation framework with a combination of WPS. The developed approaches can strengthen the advantages of independent indoor applicability of IMU. The estimation of IMU is efficiently compensated by radio fingerprint based Wi-Fi Positioning System. We put a focus especially on the hybrid algorithmic framework. Compared on the existing approaches of WPS or IMU, we achieve the comparable higher performance on both of average error of estimation and deviation of errors. Furthermore test-bed based on smart phone platform is practically developed and all data have been harvested from the actual measurement of test indoor area. This can approve the practical usefulness of proposed framework.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.4
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• pp.324-332
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• 2018

We conducted a questionnaire survey to analyze the current status of the coastal composite fisheries, as well as the improvement point in designing a new type coastal composite fishing boat suitable for Korean fishing environments from April to August 2017. The questionnaire composed of 20 questions about the features of the coastal composite fishing boat and fishing work. The survey sites were selected to cover all parts of the country by considering the geographical position. The significance testing for the response results was accessed by ${\chi}^2$ test and ANOVA. The results revealed that more than half (59.1%) of the fishermen operated one day per voyage and operating alone topped with 22.5% in the number of crews, followed by 2 persons (20.3%) and 5 persons (22.1%). The navigation devices had a high rate of installation and GPS plotter ranked first in the devices. In addition, fish finder ranked first in fishing equipment, followed by net hauler. The most inconvenient work that they felt during the fishing operation was fish handing at 49.8% and other general fishing works like setting and hauling line, deck cleaning accounted for about 25%. The hardest work was the accident by ropes wrapped around propeller and the engine trouble came in second. The most inconvenient facilities to the present design of fishing boat was wheelhouse (76.7%), followed by fish hold (38.5%), and deck (35.1%). Furthermore, inconvenient points related to the movement of fishing gear, noise and vibration of engine, slippery deck and small fish hold exceeded 50%.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.27-28
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• 2011

A solar flares have the 11-year cycle and release a large energy which may produce coronal mass ejections (CME). The NOAA (National Oceanic and Atmospheric Administration) predicted that the sun spot activity will be maximized in 2013-2014. A strong solar flare can cause the disturbance of global positioning system including various communication of TV, radio broadcasting. The actual solar storm in 1989 caused power outages in Canada during 9 hours and about 600 million people had experienced a blackout. Such a solar storm can shorten the GPS satellite's life span about 5 to 10 years which can be resulted in economic loss considering the amount of multi-billion won. This paper analyzed the recent solar storm of X-class occurred on 15th of February about 10:45 this year that was reached Korea (Bohyun observatory) on 18th of February about 10:30 (local time), and compared with the data of before and after a week. The proton data of 18th of February considered that the solar strom reached on earth showed a fluctuation compared to the data of before and after a week. The positioning results at Daejeon also showed higher positioning error compared to the data of before and after a week results.