• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.7-13
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• 2015

The number of mobile terminals equipped with a GPS module is steadily increasing today. However, because they using code pseudorange measurements in positioning, the positioning accuracy of mobile terminals is lower than that of those receivers using carrier phases. Especially, the multipath signal causes more significant errors in code pseudoranges. Therefore, the techniques of multipath detection and elimination is necessary. In this study, as an initial analysis of multipath detection and elimination technique development, we tested the feasibility of multipath signal detection using GPS signal strength information. We found that the GPS signal strength increases as the elevation angle gets higher in the open-sky environment. Also, we found that the signal strength decreases when there were some signal reflectors nearby. We checked the repeatability of the signal strength variation characteristics by reflecting repeat time of GPS satellites. As a result, this characteristics repeats almost perfectly when GPS satellites pass the same orbit. Therefore, we found that it is not a temporary phenomenon and the multipath signal detection should be possible by using GPS signal strength information.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.5
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• pp.751-760
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• 2018

Currently, the quality measurement of the work is carried out by the supervisor's visual inspection, as the workers individually judge the number of resolutions, thickness, speed and vibration. After work, we are conducting follow-up work through traditional spot test, which is less representative. Therefore, it is impossible to check the results of the resolution, and there is always the possibility that problems will arise due to poor construction. This study demonstrates the feasibility of using the continuous compaction strength measurement method by comparing the continuous compaction strength measurement method and the conventional compaction strength measurement method after performing the compaction in the actual field scale in various test conditions. The validity is verified by analyzing the Compaction Meter Value of an Intelligent Compaction roller composed of a Global Positioning System and an accelerometer, Based on the proven results, a full range of quality can be confirmed without a single test. The quality confirmation is visualized in the compaction control program developed in this study, This enables the field manager to perform real-time quality monitoring at the same time as compaction.

• Proceedings of the KSRS Conference
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• v.1
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• pp.29-33
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• 2006

The potential impact of past Caribbean tsunamis generated by earthquakes and/or massive submarine slides/slumps, as well as the tsunamigenic potential and population distribution within the Intra-Americas Sea (IAS) was examined to help define the optimal location for coastal sea level gauges intended to serve as elements of a regional tsunami warning system. The goal of this study was to identify the minimum number of sea level gauge locations to aid in tsunami detection and provide the most warning time to the largest number of people. We identified 12 initial, prioritized locations for coastal sea level gauge installation. Our study area approximately encompasses $7^{\circ}N$, $59^{\circ}W$ to $36^{\circ}N$, $98^{\circ}$ W. The results of this systematic approach to assess priority locations for coastal sea level gauges will assist in developing a tsunami warning system (TWS) for the IAS by the National Oceanic and Atmospheric Administration (NOAA) and the Intergovernmental Oceanographic Commission's Regional Sub-Commission for the Caribbean and Adjacent Regions (IOCARIBE-GOOS).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.407-409
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• 2017

Many traditional retailers are losing money due to loss and accidents in managing their carts. Therefore, we intend to solve these problems by installing a raspberry pie with various functions in order to efficiently manage the cart. First, use ultrasonic sensors to measure the distance between the cart and the object, use vibration sensors to vary the number of vibration sensors, change the number of vibrations to the user, and use Beacon to transmit the cart in real time. It also contributes to consumers' spending patterns and revenue generation by identifying consumers' consumption patterns. Problems with lost are also resolved by issuing an audible warning (outside of Mart) if a distance is removed (outside of Mart).

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.56-66
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• 2012

The Recent Specialty Contractor in construction of the reduced quantity due to the recession, but competitive in order to increase the number of companies that are increasingly competitive. The field work of one person to perform the work of employees and multiple sites, workforce supply flow that occurs at each stage of information transfer is not made a late staffing. Therefore this research has proposed a new alternative that can overcome them and the entire industry in recent issue smart phone features that take advantage of GPS(Global Positioning System). This paper presents a Diligence and Indolence Management System using GPS of smart phone. offering the advantage of Web-based PMIS(Project Management Information System) through integration with real-time information transfer and smart phone applications for query by building a prototype of a professional construction company as their own on-site management measures are proposed to contribute time and attendance.

• Archives of Craniofacial Surgery
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• v.17 no.4
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• pp.198-201
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• 2016

Background: Zygomatic arch is a bony arch constituting the lateral midface, which consists of 25% of all midface fractures. There are a number of ways to evaluate the extent of zygomatic arch fracture. Some authors have reported successful treatment outcomes using ultrasound (U/S). To add to the previous methods, we have considered ways to accurately display the location of the fracture line while using U/S with 23 gauge needle marking. We introduce our method, which provided satisfactory results for reduction using a portable U/S, and it can evaluate the fracture line simultaneously when reduction of an isolated zygomatic arch fracture is necessary, and needle marking, which can easily point out the fracture line on U/S. Methods: We studied 21 patients with an isolated zygomatic arch fracture who underwent closed reduction using U/S and needle marking between 2013 and 2015. Results: We achieved satisfactory results in all our cases with respect to reduction by using the Dingman elevator after performing a temporal approach incision, while confirming relative positioning between needle marking and zygomatic fracture at the same time, after insertion of a 23 gauge needle in the skin above the zygomatic arch fracture line parallel to it. Conclusion: We treated 21 patients with an isolated zygomatic arch fracture using U/S and the needle marking method, which provided satisfactory results because the extent of reduction of the fracture could be evaluated in real-time during the operation and exposure to radiation was reduced.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.71-78
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• 2016

In the paper, we predict the number of multi-GNSS satellites and visible satellites with the navigation satellite launch plans and their nominal orbit parameters. Based on the methodology, the multi-GNSS navigation performance and DOP (Dilution of Precision) variation from 2015 to 2020 were forecasted by the Matlab simulation. To calculate the position using the multi-GNSS constellation, we determined the time-offset between the two different systems. Two different algorithms were considered for the sake of time-offset determination; that of each was applied to system level and user side. Also, the results from two algorithms were compared for evaluating each performance. For the reality, we applied the 3D map information to the simulation, which is expected to contribute for predicting the future navigation performance in urban canyon.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.331-335
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• 2016

When a boating accident, such as a January number three, the customer's risk management issues emerged. Ships and accident risk in confined spaces such as risk management to locate the customer and dangers of probation is available. In this paper, aboard after consent to obtain information for customers to wrist to customers, webbing or portable device embedded in devices and Wireless sensor information Input was attached, disposable consumer information. Customer on board the ship setting for location analysis and positioning according to information communication protocol, ships, each customer's real-time location information on the screen, 3 the foundation of d customers on the floor Can be designed to inform. Threshold designed to reduce the error of the information to analyze the position in current position and errors. Also, to system attacks would control the situation of accident and emergency jaenanguk server with real-time information transmission of information outside the emergency during a disaster, search and Disaster relief to be possible.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.3
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• pp.285-291
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• 2004

GPS photogrammetry or the GPS/INS photogrammetry, which are based on the direct measurement of the projection centers and attitude at the moment of camera exposure time through loading the GPS receiver or INS in aircraft. Both photogrammetric methods can offer us to acquire the exterior orientation parameters with only minimum ground control points, even the ground control process could be completely skipped. Consequently, we can drastically reduce the time and cost for the mapping process. In this thesis, test flight was conducted in Suwon area to evaluate the performance of accuracy and efficiency through the analysis of results among the three photogrammetric methods, that is, traditional photogrammetry, GPS photogrammetry and GPS/INS photogrammetry. Test results shows that a large variety of advantages of GPS photogrammetry and GPS/INS photogrammetry against traditional photogrammetry is to be verified. Especially, the number of ground control points for the exterior orientation could be saved more than 70～80%, respectively.

• Archives of Plastic Surgery
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• v.48 no.5
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• pp.473-482
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• 2021

Background The increasing number of bilateral breast cancer patients has been accompanied by a growing need for bilateral mastectomy with immediate reconstruction. However, little research has investigated the complications and aesthetic outcomes related to bilateral reconstruction. Therefore, we analyzed retrospective data comparing the outcomes of bilateral reconstruction using deep inferior epigastric perforator (DIEP) flaps or implants. Methods This study included 52 patients (24 DIEP group and 28 implant group) who underwent bilateral mastectomy with immediate reconstruction between 2010 and 2020. Patient demographics, surgical characteristics, and complications were recorded. The difference between the left and right position of the nipple-areolar complex with respect to the sternal notch point at the clavicle was measured, and breast symmetry was evaluated. Results The average weight of breasts reconstructed with DIEP flaps (417.43±152.50 g) was higher than that of breasts with implants. The hospitalization period and operation time were significantly longer in the DIEP group. Early complications were significantly more common in the implant group (36.53%) than in the DIEP group. The angles between the nipples and the horizontal line were 1.09°±0.71° and 1.75°±1.45° in the DIEP and implant groups, respectively. Conclusions Although the surgical burden is lower, breast reconstruction using implants requires greater attention with respect to implant positioning, asymmetry, and complications than DIEP flap reconstruction. DIEP flap reconstruction has a prolonged operation time and a high risk of flap failure, but yields excellent cosmetic results and does not require intensive follow-up. Patients should be consulted to determine the most suitable option for them.