• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.8-13
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• 2003

In this paper, suitablility of 1 GHz CISPR limits establishment fur broadcast communication quality protection is examined and the optimum turn step resolution of EUT for spurious measurement of frequency above 1 GHz to increase the accuracy of maximum values extraction is examined. As a result of 500 MHz and 1.7 GHz clock speed personal computer of micro-processor measurement, optimum turn step resolution extracted by National Institution of National Instrument of Standard & Technology(NIST) Koepke method is estimated 40 table positions per polarization in 500 MHz. And in case of 1.7 GHz, step size is 36 table positions. Prediction of turn step size required for fully scan method in gjgahertz measurement will increase measurement accuracy and reduce considerable measurement time as well.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.719-724
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• 2004

Recently, since the number of internet users is increasing rapidly and, by using the public hacking tools, general network users can intrude computer systems easily, the hacking problem is getting more serious. In order to prevent the intrusion, it is needed to detect the sign in advance of intrusion in a positive prevention by detecting the various foms of hackers' intrusion trials to know the vulnerability of systems. The existing network-based anomaly detection algorithms that cope with port- scanning and the network vulnerability scans have some weakness in intrusion detection. they can not detect slow scans and coordinated scans. therefore, the new concept of algorithm is needed to detect effectively the various forms of abnormal accesses for intrusion regardless of the intrusion methods. In this paper, SPAD(Session Pattern Anomaly Detector) is presented, which detects the abnormal service patterns by comparing them with the ordinary normal service patterns.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.6 s.312
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• pp.16-26
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• 2006

In this paper, we propose a 3D shape restoration system which measures height and surface shape of transparent ITO glass and delivers errors in focal length and incident angle of laser beam to femto-second laser micromachining. The proposed system is composed of a line scan laser, a high resolution camera, a linear motion guide synchronized to image capturing, and a control station. Also, we define the sensitivity indices that represent a relation between measurement error and a position of a camera and scan laser, and utilize it for optimum design. The results of the proposed system are compared with results of SPM(Scanning Probe Microscope) and prove the usefulness of the system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.32-39
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• 2011

When the laws about the security of ships are revised, or voyage conditions are changed, ship owners have converted rather than built new passenger ships including cruise ships recently. As conversion causes a lot of changes in principal dimension, structural strength, hydrodynamic performance, the number of passengers, and cargo capacity, detailed pre-review is needed. But any studies on conversion have not been carried out yet, this study investigated and analyzed the trend of consulting companies' reports (Delta Marine Report, 2005, 2008). As a result, it was found that lengthening conversion brought about the main changes in principal dimension, and performance. Also it was suggested that there be factors for consideration like hull scantling, hull form, and cutting point to minimize side effects when ship owners build ships having lengthening conversion in mind.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.195-200
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• 2021

With the development of transportation and mobiles demand for tourism travel is increasing and related industries are also developing significantly. The combination of augmented reality and tourism contents one of the areas of digital media technology, is also actively being studied, and artificial intelligence is already combined with the tourism industry in various directions, enriching tourists' travel experiences. In this paper, we propose a system that scans miniature models produced by reducing tourist areas, finds the relevant tourist sites based on models learned using deep learning in advance, and provides relevant information and 3D models as AR services. Because model learning and object detection are carried out using YOLOv3 neural networks, one of various deep learning neural networks, object detection can be performed at a fast rate to provide real-time service.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.80-90
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• 2022

With the development of digital dentistry, it is being applied in various ways of dental treatment. This case report presents the definitive prosthesis designed in advance with a re-established vertical dimension and the digital technology, which determined the amount of tooth preparation, in order to preserve as much tooth structure as possible in a patient with pathological wear of the posterior teeth and loss of vertical dimension. For accurate tooth preparation, the guides of the occlusal and axial surfaces were digitally and additively manufactured. Then, aesthetics and anterior guidance were established at the provisional stage. The information of the provisional restoration was delivered to the definitive stage by double scanning. The digital technology, including the virtual planning and the guided tooth removal, produced the definitive restorations satisfactory to both the patient and clinician.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.492-501
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• 2007

Coastal disasters have become one of the most important issues in every coastal country. In Korea, coastal disasters such as storm surge, sea level rise and extreme weather have placed many coastal regions in danger of being exposed or damaged during subsequent storms and gradual shoreline retreat. A storm surge is an onshore gush of water associated with a tow pressure weather system, typically in typhoon season. However, it is very difficult to predict storm surge height and inundation due to the irregularity of the course and intensity of a typhoon. To provide a new scheme of typhoon damage prediction model, the scenario which changes the central pressure, the maximum wind radius, the track and the proceeding speed by corresponding previous typhoon database, was composed. The virtual typhoon scenario database was constructed with individual scenario simulation and evaluation, in which it extracted the result from the scenario database of information of the hereafter typhoon and information due to climate change. This virtual typhoon scenario database will apply damage prediction information about a typhoon. This study performed construction and analysis of the simulation system with the storm surge/coastal inundation model at Masan coastal areas, and applied method for predicting using the scenario of the storm surge.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.330-337
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• 2018

In edentulous patients, implant - supported fixed prosthesis treatment has been proved to be useful, but involves complex treatment process. On the other hand, in the modern dentistry, digital technology has been developed day by day and it has expanded its range to the implant restoration of edentulous patients. In this case, a digital system was used for all stages of diagnosis, surgery, design and fabrication of provisional implants fixed prosthesis restoration in 66-year-old mandibular edentulous patients. In the preoperative diagnosis stage, a provisional restoration was designed based on the mucosal scan using the intraoral scanner and the stable occlusion of prefabricated complete denture of the patient. After flapless implant surgery using the surgical guide, the prefabricated interim restoration was connected to the implant and used as immediate provisional restoration. The final restoration was designed and fabricated by transferring the vertical dimension and the centric relation of the provisional restoration with stable occlusion using digital technology. We report a simple protocol of implant treatment in edentulous patients by using digital techniques to preserve the patient's vertical dimension and occlusion.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.55-65
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• 2016

Detecting an object which is located at seabed is an important issue for various areas. This paper presents an approach to detection of an object that is placed at seabed in the shallow water. A conventional scheme is to employ a side-scan sonar to obtain images of a detection area and to use image processing schemes to recognize an object. Since this approach relies on high frequency signals to get clear images, its detection range becomes shorter and the processing time is getting longer. In this paper, we consider an active sonar system that is repeatedly sending a linear frequency modulated signal of 6~20 kHz in the shallow water of 100m depth. The proposed approach is to model consecutively received reflected signals and to measure their modeling error magnitudes which decide the existence of an object placed on seabed depending on relative magnitude with respect to threshold value. The feature of this approach is to only require an assumption that the seabed consists of an homogeneous sediment, and not to require a prior information on the specific properties of the sediment. We verify the proposed approach in terms of detection probability through computer simulation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.4
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• pp.311-319
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• 2013

As heavy rains occur more frequently due to the recent climate change, slope collapses are increasing, and damage to human life and properties is accordingly increasing every year. The most proper method to take preventive measures against slope collapses is to remove the cause after understanding the cause of slope collapse in advance, and for such, slope safety inspection is implemented for preventive purposes, to investigate the cause, and as a measure for restoration. Thus, this Research was able to reach the following conclusion after utilizing LiDAR, which obtains detailed topographic information in a short period of time with point cloud data on slopes subject to safety inspection. First, as a result of analyzing the errors after installing a check point in the subject area, the RMSE of the horizontal location error appeared to be ${\pm}2.2cm$ and the RMSE of the vertical location error appeared to be ${\pm}3.0cm$, which shows a practically satisfactory result. Second, the economic feasibility was outstanding and obtaining accurate topographic information was available. Third, an area once scanned allowed to accurately obtain an unprescribed cross-sectional diagram in a short period of time, thus, appeared to be convenient for experts to detect dangerous sections.