• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.490-493
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• 2000

Mesiodens are supernumerary teeth in the region of the maxillary central incisors, a condition which can lead to disorders of the dentition. Their presence may lead to disorders, such as delay in eruption of permanent teeth, development of dentigerous cysts, resorption of adjacent roots and eruption of a supernumerary tooth into nasal cavity. The optimal time for surgical intervention is controversial. Early diagnosis is important so as to enable good prognosis. Diagnosis primarily depends on x-ray films. Panorama film, occlusal film, periapical film have been used for detection of mesiodens. But, all of them have disadvantages. $SCANORA^{(R)}$ is a multimodal radiology system which utilizes the principles of narrow beam radiology and spiral tomography. Pre-programmed imaging procedure are provided for many dental situations An optional personal computer can be connected into the unit to help design the examination. We report two cases diagnosed by $SCANORA^{(R)}$. When compared with tube shift technique, it is simple and exact method of detecting mesiodens.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.327-330
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• 2017

In recent years, Drone(lightweight unmanned aerial vehicle) is used for broadcast shooting, disaster scene, leisure, observation and military purposes. However, as the use of drones increases the threat of hacking is also rising. Especially when a flying drone is seized, a dangerous situation can occur which is abused regardless of the driver's intention. Already in Iran and China, there is a case of hacking and stealing the drones of other countries under reconnaissance. In this paper, we analyze the security vulnerabilities of Wi-Fi and Bluetooth communication in wireless network which are used in drones for stealing the commercial drones. The results provide a countermeasure to safeguard the drones against attempts by the unauthorized attacker to take out the drones.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.92-97
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• 2000

Low-velocity impact damage of a thick pressure vessel by composite materials was studied using the modified Herzian contact radius theory. Impactors of various masses and various tup shapes were dropped freely in the range of 20m to 200mm height. With acceleration gage and strain gage installed on the impactor, impact force and acceleration and Contact radius were measured. After a test, the samples were radiographed to scan the state of damage. Compared with hemispherical tup of 12.7mm diameter, the contact radius of hemispherical tup of 25.4mm diameter was bigger. And the experimental data and the theoretical data was different due to the mechanical properties difference. The acceleration value was changed linearly according to the height.

• Imaging Science in Dentistry
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• v.37 no.2
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• pp.103-110
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• 2007

Purpose: To examine the danger zone of mesial root of mandibular first molar of patient without extraction using CBCT (cone-beam computed tomography) to avoid the risk of root perforation. Materials and Methods: 20 mandibular first molars without caries and restorations were collected, CT images were obtained by CBCT ($PSR9000N^{TM}$, Asahi Roentgen Co., Japan), reformed and analyzed by V-work 5.0 (CyberMed Inc., Korea), Distance between canal orifice and furcation was measured. In cross sectional images at 3, 4 and 5 mm below the canal orifice, distal wall thickness of mesiobuccal canal (MB-D), distal wall thickness of mesiolingual canal (ML-D), distal wall thickness of central part (C-D), mesial wall thickness of mesiobuccal canal (MB-M) and mesial wall thickness of mesiolingual canal (ML-M) were measured, Results: The mean distance between the canal orifice and the furcation of the roots is 2.40 mm, Distal wall is found to be thinner than mesial wall. Mean dentinal wall thickness of distal wall is about 1 mm, The wall thickness is thinner as the distance from the canal orifice is farther. But significant differences are not noted between 4 mm and 5 mm in MB-D and C-D, MB-D is thinner than ML-D although the differences is not significant. Conclusion: The present study confirmed the anatomical weakness of distal surface of the coronal part of the mesial roots of mandibular first molar by CBCT and provided an anatomical guide line of wall thickness during endodontic treatment.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.359-366
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• 2013

Due to the development and market expansion of image analysis and recognition technology, video security such as CCTV cameras and digital storage devices, are required for real-time monitoring systems and intelligent video security systems. This includes the development of more advanced technologies. A rotatable PTZ camera, in a CCTV camera system, has a zoom function so you can acquire a precise picture. However it can cause blind spots, and can not monitor two or more moving objects at the same time. This study concerns, the intelligent tracking of multiple moving objects, CCTV systems, and methods of video surveillance. An intelligent video surveillance system is proposed. It can accurately shoot broad areas and track multiple objects at the same time, much more effectively than using one fixed camera for an entire area or two or more PTZ cameras.

• Journal of IKEEE
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• v.19 no.4
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• pp.535-540
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• 2015

A microstrip gas chamber (MSGC), applied to digital radiography system, was designed and constructed. The microstrip electrodes were fabricated with Chrome(Cr.). by photolithography process on Silicon(Si) wafer and glass substrate. The width of anode and cathode electrodes was $10{\mu}m$, and $290{\mu}m$, respectively. The distance of the electrodes was $100{\mu}m$, and the active area was $50{\times}50mm^2$. And the number of anode was 80. The microstrip electrodes were damaged when discharges occurred over the 600 V of anode voltage. As the result of experiments. It detected the typical output signals of the pulse width, 20 ns, under the condition that the detecting gas was Ar(90%) + $CH_4$(10%), X-ray tube voltage was 42 kV, and tube current was 1 mA.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.217-239
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• 1999

Investigation methods of cut slope are conducted generally only geological surface survey to gain engineering geological data of cut slopes. These methods have many problems such as limitation of investigation for a special area. So geophysical investigations such as geotomography, seismic and electrical resistivity methods have been used to search for failure surface in potential failure slopes or failed slopes. But investigation method using the borehole camera is recently a used method and it is thought that this method is more reliable method than other investigation methods because of being able to see by the eyes. Therefore, this paper was conducted investigations of 4 boleholes and BIPS (Borehole Image Processing System) to search for potential sliding surfaces and was applied to obtain information of discontinuity on failed highway slope. As the results of BIPS, we could decide potential sliding surface in the slope and conducted to check slope stability. And decided slope stability measures.

• 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.

• Journal of radiological science and technology
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• v.43 no.4
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• pp.259-264
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• 2020

Radiation causes radiation hazards in the human body. In Korea, a case of radiation necrosis occurred in 2014. In this study, the scatter and shielding efficiency according to lead shielding were classified into epidermis and dermis for 0.511 MeV used in nuclear medicine. In this study, experiments were conducted using the slab phantom that represents calibration and the dose of human trunk. Experimental results showed that the shielding rate of 0.25 mmPb was 180% in the epidermis and 96% in the dermis. Shielding at 0.5mmPb showed shielding rates of 158%in the epidermis and 82% in the dermis. As a result of measuring the absorbed dose by subdividing the thickness of the dermis into 0.5 mm intervals, when the shielding was carried out at 0.25 mmPb, the dose appeared to be about 120% at 0.5 mm of the dermis surface, and the dose was decreased at the subsequent depth. Shielding at 0.5 mmPb, the dose appeared to be about 101% at the surface 0.5 mm, and the dose was measured to decrease at the subsequent depth. This result suggests that when lead aprons are actually used, the scattering rays would be sufficiently removed due to the spaces generated by the clothes and air, Therefore, the scattered ray generated from lead will not reach the human body. The ICRU defines the epidermis (0.07), in which the radiation-induced damage of the skin occurs, as the dose equivalent. If the radiation dose of the dermis is considered in addition, it will be helpful for the evaluation of the prognosis for radiation hazard of the skin.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.506-511
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• 2017

LED lighting, which many companies are pursuing commercialization, is a representative green energy technology. However, the LED lighting for broadcasting image should have high output and easy portability compared with general LED lighting devices for street lamps, advertisement or transportation devices. Therefore, while shooting a broadcast image if you use LEDs as a substitute light source for halogen lamps and fluorescent lamps that are large in size and uncomfortable to handle it is expected that the lightening of the equipment will activate the broadcasting image lighting equipment industry. After considering the mass production of the LED module board and the SMT production size of the chip mounter, the board size was determined considering the overall size of the product by model. In this paper, four 20W LED boards are arranged vertically in order to produce an 80W board. In other words, by sharing LED module board size by model, high power LED lighting equipments of 120W and 200W can be selected as an increase in the number of boards.