• Composites Research
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• v.28 no.4
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• pp.155-161
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• 2015

A composite structure was fabricated with embedded impact detection capabilities for applications in Structural Health Monitoring (SHM). By embedding sensor functionality in the composite, the structure can successfully perform impact localization in real time. Smart resin, composed of $Pb(Ni_{1/3}Nb_{2/3})O_3-Pb(Zr,\;Ti)O_2$ (PNN-PZT) powder and epoxy resin with 1:30 wt%, was used instead of conventional epoxy resin in order to activate the sensor function in the composite structure. The embedded impact sensor in the composite was fabricated using Hand Lay-up and Vacuum Assisted Resin Transfer Molding(VARTM) methods to inject the smart resin into the glass-fiber fabric. The electrodes were fabricated using silver paste on both the upper and bottom sides of the specimen, then poling treatment was conducted to activate the sensor function using a high voltage amplifier at 4 kV/mm for 30 min at room temperature. The composite's piezoelectric sensitivity was measured to be 35.13 mV/N by comparing the impact force signals from an impact hammer with the corresponding output voltage from the sensor. Because impact sensor functionality was successfully embedded in the composite structure, various applications of this technique in the SHM industry are anticipated. In particular, impact localization on large-scale composite structures with complex geometries is feasible using this composite embedded impact sensor.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.549-558
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• 2021

In order to keep infrastructures such as tunnels and underground facilities safe, cracks of concrete lining in tunnel should be detected by regular inspections. Since regular inspections are accomplished through manual efforts using maintenance lift vehicles, it brings about traffic jam, exposes works to dangerous circumstances, and deteriorates consistency of crack inspection data. This study aims to provide methodology to automatically extract cracks from tunnel concrete lining images generated by the existing tunnel image acquisition system. Specifically, we train a deep learning based semantic segmentation model with open dataset, and evaluate its performance with the dataset from the existing tunnel image acquisition system. In particular, we compare the model performance in case of using all of a public dataset, subset of the public dataset which are related to tunnel surfaces, and the tunnel-related subset with negative examples. As a result, the model trained using the tunnel-related subset with negative examples reached the best performance. In the future, we expect that this research can be used for planning efficient model training strategy for crack detection.

• Journal of Internet of Things and Convergence
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• v.10 no.2
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• pp.69-75
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• 2024

This paper proposes an IoT-based indoor autonomous driving system that applies SLAM (Simultaneous Localization And Mapping) and Navigation techniques in a ROS (Robot Operating System) environment based on TurtleBot3. The proposed autonomous driving system can be applied to indoor autonomous wheelchairs and robots. In this study, the operation was verified by applying it to an indoor self-driving wheelchair. The proposed autonomous driving system provides two functions. First, indoor environment information is collected and stored, which allows the wheelchair to recognize obstacles. By performing navigation using the map created through this, the rider can move to the desired location through autonomous driving of the wheelchair. Second, it provides the ability to track and move a specific logo through image recognition using OpenCV. Through this, information services can be received from guides wearing uniforms with the organization's unique logo. The proposed system is expected to provide convenience to passengers by improving mobility, safety, and usability over existing wheelchairs.

• Journal of Astronomy and Space Sciences
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• v.22 no.1
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• pp.1-12
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• 2005

The Korean VLBI Network (KVN) will open a new field of research in astronomy, geodesy and earth science using the newest three Elm radio telescopes. This will expand our ability to look at the Universe in the millimeter regime. Imaging capability of radio interferometry is highly dependent upon the antenna configuration, source size, declination and the shape of target. In this paper, imaging simulations are carried out with the KVN system configuration. Five test images were used which were a point source, multi-point sources, a uniform sphere with two different sizes compared to the synthesis beam of the KVN and a Very Large Array (VLA) image of Cygnus A. The declination for the full time simulation was set as +60 degrees and the observation time range was -6 to +6 hours around transit. Simulations have been done at 22GHz, one of the KVN observation frequency. All these simulations and data reductions have been run with the Astronomical Image Processing System (AIPS) software package. As the KVN array has a resolution of about 6 mas (milli arcsecond) at 220Hz, in case of model source being approximately the beam size or smaller, the ratio of peak intensity over RMS shows about 10000:1 and 5000:1. The other case in which model source is larger than the beam size, this ratio shows very low range of about 115:1 and 34:1. This is due to the lack of short baselines and the small number of antenna. We compare the coordinates of the model images with those of the cleaned images. The result shows mostly perfect correspondence except in the case of the 12mas uniform sphere. Therefore, the main astronomical targets for the KVN will be the compact sources and the KVN will have an excellent performance in the astrometry for these sources.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.1
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• pp.73-77
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• 2004

Purpose of the radio-therapy is maximize the radiation dose to the tumor while minimizing the dose to the critical organ. Carcinoma of the uterine cervix treatment are external irradiation or an interstitial brachtheraphy make use of isotope. Brachytherapy is a method of radiotherapy in advantage to achieve better local control with minimum radiation toxicity in comparison with external irradiation because radiation dose is distributed according to the inverse square low of gamma-ray emitted from the implanted sources. Authors make use of the patients data which 192Ir gives medical treatment intrcavity. Intracavitary radiation of the uterine cervix cancer, critical organ take $20\%$ below than exposure dose of A point in the ICRU report. None the less of the advice, Radiation proctitis and radiation cystitis are frequent and problematic early complications in patients treated with radiation for the uterine cervix cancer. In brachytherapy of uterine cervical cancer using a high dose rate remote afterloading system, it is of prime importance to deliver a accurate dose in each fractionated treatment by minimizing the difference between the pre-treatment planned and post-treatment calculated doses. Use of packing to reduce late complications intracavitary radiation of the uterine cervix cancer. Bladder and rectum changes exposure dose rate by radiotherphy make use of packing.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.242-281
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• 2010

There are a large number of Buddhist cultural relics in Mt. Namsan. The cultural relics carry the spirit of people of Shila who dream of Buddhist Elysium and the establishment of Buddhist nation. In the valley and the top of the mountain and on various rock cliff, stone statues of Buddha and stone pagodas stand in harmony with nature. For that reason, Mt. Namsan is called an open-air museum. And it played an important role in establishing 'The UNESCO World Heritage' status for Gyeongdju in December 2000. But sadly, there are many stone relics that have eroded away and damaged from collapsing in the passage of time. The seated stone statue of Buddha in Samreoung valley of Mt. Namsan is one of them. It was created between the 8th and 9th century, and restored without much care nor extensive historical research in 1923. As a result, The face of the Buddha remained with concrete mortar and its nimbus fallen backward and destroyed. Therefore, restoration and repair as well as creation of a statue environment for the statue were urgent. So we immediately started in restoration and repair. First, through the archaeological excavation around the stone Buddha, we carried the stone Buddha on the original position. In order to restore the statues to its original glory created by the Unified Shila Dynasty, we created a restoration plan in corporation with art historians and historians, then restored the jaw and the damage nimbus. Second, we made the weathering & damage map of the stone Buddha. In order to prevent second damage, we cleaned the surface of contaminants with distilled water. Third, we studied restoration method to prevent artificial damage. We recreated parts of his face and halo. Then each parts of the statue were restored to their original position. In the whole process of restoration, we tried to use traditional techniques.

• MISULJARYO - National Museum of Korea Art Journal
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• v.99
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• pp.50-71
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• 2021

The Five-story Stone Pagoda from the Dongsa-ri Temple Site in Buyeo, dated to early Goyeo Dynasty, is valuable in that it is the southernmost example of the capital Kaesong pagoda style. This pagoda exhibits characteristics of the central Goryeo style featured in the pagodas built in and around the capital Kaesong, such as the diagonally curved section of the support for the cover stone above the upper stereobate. It also shares stylistic affinities with eleventh-century stone pagodas. The ansangmun (elephant eye patterns) in the lower stereobate of the Dongsa-ri Five-story Stone Pagoda resemble those in the pedestal of the Stone Seated Buddha (which was likely repaired in 1028 during the reign of King Hyeonjong), at the Jeongrimsa Temple site in Buyeo. It also reflects elements found in the flagpole supports from the Cheonheungsa Temple site in Cheonan. The sculpting techniques used in these patterns are also similar. Such congruencies suggest that the Dongsa-ri Five-story Stone Pagoda was built in the eleventh century. The Dongsa-ri Temple Site in Buyeo, located near the Geumgang River, served as a principal route for transporting grain-tax during the Goryeo Dynasty. It was also situated along the way to the Goryeo royal temple, Gaetaesa Temple. The geographical significance of the site and the extensive repairs undertaken at Jeongrimsa Temple during the reign of King Hyeonjong (r. 1009-1031) of the Goryeo Dynasty appear to have impacted the production of the Dongsa-ri Five-story Stone Pagoda. The Dongsa-ri Five-story Stone Pagoda also bears stylistic resemblances to the stone pagoda and flagpole supports found at neighboring Cheonheungsa Temple, which is presumed to be related to the establishment of Honggyeongsa (or Honggyeongwon) Temple in 1021 in Cheonan. This indicates the route of the transmission of the Kaesong pagoda style. The Five-story Stone Pagoda from the Dongsa-ri Temple Site pays testimony to the cultural accomplishments of eleventh-century stone artworks in Buyeo and adjacent regions. This pagoda embodies the majestic and assertive aesthetics that define of the Goryeo Dynasty, as do early Goryeo colossal Buddhist sculptures, including the Stone Standing Maitreya Bodhisattva at Daejosa Temple in Buyeo, the Stone Standing Buddha Triad at Gaetaesa Temple in Nonsan, and the Stone Standing Maitreya Bodhisattva at Gwanchoksa Temple in Nonsan. All of these bear similarities to the massive stone lantern and pagoda at Hyeonhwasa Temple in the capital Kaesong. The production of the light, sleek, sharp, and sophisticated Dongsa-ri Five-story Stone Pagoda is presumed to reflect the maturity of the cultural competence of the people in Dongsa-ri, Buyeo under the influence of Buddhist culture from the capital Kaesong during the eleventh century, a time marked by active cultural exchanges among regions.

• Journal of IKEEE
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• v.23 no.4
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• pp.1461-1464
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• 2019

In this paper, we propose the development of embedded board for integrated radiation exposure protection fireman's life-saving alarm capable of location tracking and radiation measurement. The proposed techniques consist of signal processing unit, communication unit, power unit, main control unit. Signal processing units apply shielding design, noise reduction technology and electromagnetic wave subtraction technology. The communication unit is designed to communicate using the wifi method. In the main control unit, power consumption is reduced to a minimum, and a high performance system is formed through small, high density and low heat generation. The proposed techniques are equipment operated by exposure to poor conditions, such as disaster and fire sites, so they are designed and manufactured for external appearance considering waterproof and thermal endurance. The proposed techniques were tested by an authorized testing agency to determine the effectiveness of embedded board. The waterproof grade has achieved the IP67 rating, which can maintain stable performance even when flooded with water at the disaster site due to the nature of the fireman's equipment. The operating temperature was measured in the range of -10℃ to 50℃ to cope with a wide range of environmental changes at the disaster site. The battery life was measured to be available 144 hours after a single charge to cope with emergency disasters such as a collapse accident. The maximum communication distance, including the PCB, was measured to operate at 54.2 meters, a range wider than the existing 50 meters, at a straight line with the command-and-control vehicle in the event of a disaster. Therefore, the effectiveness of embedded board for embedded board for integrated radiation exposure protection fireman's life-saving alarm has been demonstrated.

• Progress in Medical Physics
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• v.19 no.2
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• pp.102-112
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• 2008

We developed a high-resolution micro-CT system based on rotational gantry and flat-panel detector for live mouse imaging. This system is composed primarily of an x-ray source with micro-focal spot size, a CMOS (complementary metal oxide semiconductor) flat panel detector coupled with Csl (TI) (thallium-doped cesium iodide) scintillator, a linearly moving couch, a rotational gantry coupled with positioning encoder, and a parallel processing system for image data. This system was designed to be of the gantry-rotation type which has several advantages in obtaining CT images of live mice, namely, the relative ease of minimizing the motion artifact of the mice and the capability of administering respiratory anesthesia during scanning. We evaluated the spatial resolution, image contrast, and uniformity of the CT system using CT phantoms. As the results, the spatial resolution of the system was approximately the 11.3 cycles/mm at 10% of the MTF curve, and the radiation dose to the mice was 81.5 mGy. The minimal resolving contrast was found to be less than 46 CT numbers on low-contrast phantom imaging test. We found that the image non-uniformity was approximately 70 CT numbers at a voxel size of ${\sim}55{\times}55{\times}X100\;{\mu}^3$. We present the image test results of the skull and lung, and body of the live mice.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.387-395
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• 2018

This study was conducted to identify DNA markers related to resistance to herbicide containing mesotrione in Tongil type rice. Two Tongil type elite lines; Milyang154 and Suweon382, showed resistance to mesotrione, whereas the others were susceptible at 20 days after mesotrione application, and severe growth inhibition was observed in the remaining 13 lines. As a result of analysis of mesotrione resistance using 190 $F_2$ populations derived from a cross of Hanareum2 (susceptible) and Milyang154 (resistant), the mesotrione resistance locus was shown to be a single dominant gene with a 3:1 segregation ratio ($X^2=1.19$, P=0.31). To identify a DNA marker closely linked to the mesotrione resistance gene, bulked segregant analysis (BSA) was adopted. The DNA marker RM3501 was identified on chromosome 2 with a recombinant value of 0.53 to the mesotrione resistance gene. Mst1(t) was located between SSR (simple sequence repeat) markers RM3501 and RM324 with a physical map distance of 10.2 Mb-11.4 Mb on chromosome 2. The band pattern of agarose gel electrophoresis of the SSR marker RM3501 showed the same segregation pattern with respect to mesotrione treatment in 20 Tongil type varieties and a $BC_2F_2$ segregation population derived from a cross between Unkwang (resistant) and Hanareum2 (susceptible). Thus, the RM3501 DNA marker could be used in breeding programs for Marker Assisted Selection in mesotrione resistant rice breeding.