• Smart Structures and Systems
• /
• v.30 no.4
• /
• pp.385-395
• /
• 2022

Detecting cracks on a concrete structure is crucial for structural maintenance, a crack being an indicator of possible damage. Conventional crack detection methods which include visual inspection and non-destructive equipment, are typically limited to a small region and require time-consuming processes. Recently, to reduce the human intervention in the inspections, various researchers have sought computer vision-based crack analyses: One class is filter-based methods, which effectively transforms the image to detect crack edges. The other class is using deep-learning algorithms. For example, convolutional neural networks have shown high precision in identifying cracks in an image. However, when the objective is to classify not only the existence of crack but also the types of cracks, only a few studies have been reported, limiting their practical use. Thus, the presented study develops an image processing procedure that detects cracks and classifies crack types; whether the image contains a crazing-type, single crack, or multiple cracks. The properties and steps in the algorithm have been developed using field-obtained images. Subsequently, the algorithm is validated from additional 227 images obtained from an open database. For test datasets, the proposed algorithm showed accuracy of 92.8% in average. In summary, the developed algorithm can precisely classify crazing-type images, while some single crack images may misclassify into multiple cracks, yielding conservative results. As a result, the successful results of the presented study show potentials of using vision-based technologies for providing crack information with reduced human intervention.

• Journal of Broadcast Engineering
• /
• v.23 no.5
• /
• pp.606-613
• /
• 2018

This study is concerned with implementing an external memory expansion device for large-scale image processing. It consists of an external memory adapter card with a PCI(Peripheral Component Interconnect) Express Gen3 x8 interface mounted on a graphics workstation for image processing and an external memory board with external DDR(Dual Data Rate) memory. The connection between the memory adapter card and the external memory board is made through the optical interface. In order to access the external memory, both Programmable I/O and DMA(Direct Memory Access) methods can be used to efficiently transmit and receive image data. We implemented the result of this study using the boards equipped with Altera Stratix V FPGA(Field Programmable Gate Array) and 40G optical transceiver and the test result shows 1.6GB/s bandwidth performance.. It can handle one channel of 4K UHD(Ultra High Density) image. We will continue our study in the future for showing bandwidth of 3GB/s or more.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.1
• /
• pp.1-8
• /
• 2011

This study is about the limits of GTEM cell using correlation factor between the OATS(Open area Test Site) and the GTEM cell. First, the field strengths at the 10 m distance OATS and in GTEM cell to obtain the experimental correlation factor are measured. Also, the EMI limits of radiated power are derived in GTEM cell as 3 position method is inversely transformed. The field strengths that calculated from theoretical models by 3 and 15 position methods are programmed and compared with measured data at the OATS. As the EMI limits of GTEM cell is newly defined, it will be use to substitute GTEM cell for OATS to efficiently measure EMI(Electromagnetic Interference).

• Journal of Plant Biotechnology
• /
• v.6 no.4
• /
• pp.221-227
• /
• 2004

Protocol was established for production of virus free healthy seeds using meristem ($0.3-0.5\;\cal{mm}$ in size) culture and field management under net house condition in tomato. The isolated meristem was found well established in MS liquid medium containing $0.1\;\cal{mg}\;1^{-1}\;of\;GA_3$. For shoot and root development either from primary meristem or from nodal segment of meristem derived plants, semisolid MS medium having $0.5\;\cal{mg}\;1^{-1}$ of IBA was found most effective. The elimination of the studied viruses (ToMV, CMV, ToLCV) in meristem-derived plants was confirmed by DAS-ELISA test. For field management of the virus eradicated meristem-derived plants, use of net house was found very effective measures to check viral vector visit and eventually infection. The meristem-derived plants were vigor and high yielder than the native seed derived plants and produced healthy seeds. Due to stop vector visit, no viral symptoms were observed in both $R_1\;and\;R_2$ plants cultivated in net house condition. Starting of viral infestation was observed in $R_2$ generation when they were planted in open house condition without control of vector visit. Therefore, for management of viral diseases, use of virus free meristem derived plantlets and their subsequent cultivation in soil under net house condition without using any vector killing insecticide can be recommended for producing healthy seeds in tomato. The developed protocol for environmentally healthy tomato seed production in Bangladesh may be used in the countries having similar tropical like environment conducive for viral vector visit.

• Journal of the Society of Naval Architects of Korea
• /
• v.55 no.1
• /
• pp.56-65
• /
• 2018

Pressure oscillation caused by the compressibility of entrapped air in dam break flow is analyzed using an open source code, which is a two-phase compressible code for non-isothermal immiscible fluids. Since compressible flows are computed based on a pressure-based method, the code can handle the equation of state of barotropic fluid, which is virtually incompressible. The computed time variation of pressure is compared with other experimental and computational results. The present result shows good agreements with other results until the air is entrapped. As the entrapped air bubbles pulsate, pressure oscillations are predicted and the pressure oscillations damp out quickly. Although the compressibility parameter of water has been varied for a wide range, it has no effects on the computed results, because the present equation of state for water is so close to that of incompressible fluid. Grid independency test for computed time variation of pressure shows that all results predict similar period of pressure oscillation and quick damping out of the oscillation, even though the amplitude of pressure oscillation is sensitive to the velocity field at the moment of the entrapping. It is observed that as pressure inside the entrapped air changes quickly, the pressure field in the neighboring water adjusts instantly, because the sound of speed is much higher in water. It is confirmed that the period of pressure oscillation is dominated by the added mass of neighboring water. It is found that the temperature oscillation of the entrapped air is critical to the quick damping out of the oscillations, due to the fact that the time averaged temperature inside the entrapped air is higher than that of surrounding water, which is almost constant.

• Research in Community and Public Health Nursing
• /
• v.13 no.3
• /
• pp.423-432
• /
• 2002

This study was conducted to test the validity of characteristics of family nursing phenomena in Korea identified in a previous study by Yoon, S. Y, et al. (1999). Data for this study were collected from 355 (first measurement 186, second measurement 169) nurses whose family nursing careers were more than one year using a cross sectional survey method. The distribution per one characteristic ranged between 0 to 5. The phenomena that had two or more characteristics and had a score of 3.0 points or more included disturbance in marital role', 'disturbance in family communication', 'inappropriate family coping', 'lack of family intimacy', 'unhealthy life style', 'deficit of financial management skill and support', 'inadequate care management sick member', and' inadequate home-making'. The essential characteristics of the 8 phenomena presented above included 27 items. Further studies on family nursing phenomena in Korea are needed to support the evidence through surveys of families in the field. A reconfirmation study, as well as qualitative research on the low validity of the characteristics, needs to be more performed in the future.

• Applied Biological Chemistry
• /
• v.43 no.4
• /
• pp.291-297
• /
• 2000

This study was conducted to find out the environmental factors affecting the differences in the half-life of the insecticide cyfluthrin in soil between field and laboratory tests carried out in 1998. Degradation and leaching of cyfluthrin in soil were examined under various environmental conditions that were considered to affect the residuality. Cyfluthrin was degraded 1.9 times faster in non-sterilized soil than in sterilized soil and 1.2 times at $25^{\circ}C$ than at $15^{\circ}C$. The half-lives of cyfluthrin were 61.4 days under the dark condition and 4.5 days under sunlight, and those were 11.8 days under the open condition and 23.8 days under the closed condition. The half-lives of the authentic compound and the commercial product of cyfluthrin were 15 and 1 day in the field test and 26 and 3 days in the laboratory test, respectively. Cyfluthrin was rapidly degraded with an increase in soil moisture content and decomposed faster in the alkaline solution of pH 12 than in the acidic solution of pH 3, but the half-life of cyfluthrin did not make any difference between pH 6.4 of the field test soil and pH 5.6 of the laboratory test soil. Cyfluthrin was immobile in soil from the results that $81{\sim}94%$ of the initial amount remained in the $0{\sim}2\;cm$ layer of the soil column regardless of the amount and time of rainfall after the chemical treatments. From viewing the abovementioned results, soil moisture content, sunlight and formulation type affected greatly soil microbes and volatilization affected slightly, and temperature, pH and rainfall did not affect the big difference in the half-life of cyfluthrin in soil between the field and laboratory tests in the year of 1998.

• Journal of Korean Society of Forest Science
• /
• v.109 no.1
• /
• pp.31-40
• /
• 2020

This study aimed to investigate the effects of climate change on the survival and growth performance of Pinus densiflora and Larix kaempferi seedlings using open-field experimental warming and precipitation manipulation. We measured the survival rate, root-collar diameter, and height, and then calculated the seedling quality index (SQI) of 2-year-old seedlings under 6 treatments [2 temperatures (TC: Control; TW: Warming) × 3 precipitation manipulations (PC: Control; PD: Decreased; PI: Increased)] and performed a two-way ANOVA to test for differences.The air temperature of the warming plots was 3℃ higher than that of the control plots, while the precipitation manipulation plots received ±40% of the precipitation received by the control plots. Temperature and precipitation treatments did not significantly affect the survival rate of P. densiflora; however, the SQI of P. densiflora decreased with increasing precipitation. In contrast, the mortality rate of L. kaempferi increased with increasing temperature and decreasing precipitation. Furthermore, in L. kaempferi, TC × PI treatment resulted in the lowest SQI with a significant interaction effect observed between the two factors. In summary, low seedling production and quality should be expected in P. densiflora as precipitation increases and in L. kaempferi as temperature increases or precipitation decreases. These results indicate species-specific sensitivities to climate change of two plant species at the nursery stage. With the occurrence of global warming, the frequencies of drought and heavy rainfall events are increased, and this could affect the survival and seedling quality of tree species. Therefore, it is necessary to improve nursery techniques by establishing new adaptation strategies based on species-specific growth performance responses.

• Journal of Korean Medicine Rehabilitation
• /
• v.19 no.2
• /
• pp.1-25
• /
• 2009

Objectives : The purpose of this study was to investigate the effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang, YGKT) and electrical acupuncture treatment in spinal cord injury(SCI)-induced rats. Methods : The subjects were divided into 5 groups ; Normal, Control-no treatment after SCI, Experimental I(Exp. I)-taken with YGKT 500 mg/kg $0.5m{\ell}$ daily after SCI. Experimental II(Exp. II)-taken with electrical acupuncture after SCI and Experimental III(Exp. III)-taken with YGKT 500 mg/kg $0.5m{\ell}$ and electrical acupuncture after SCI. After each operation, the present author observed cytological changes, the motor behavior recovery and nerve regeneration by analysis of the motor behavior tests, EMG, hematological(AST, ALT, WBC), histological and immunological changes. Rats were tested by Motor behavior test at 1st, 3rd, 7th, 14th and 21st day. Results : 1. All the experimental groups were improved compared with control group in the motor behavior tests including Tarlov test, Basso-Beattle-Bresnahan locomotor rating scale, modified inclined plane test, open field test, grid walk test and narrow beam test. Especially Exp. III was significantly improved among other groups. 2. In EMG test, H and M wave were significantly increased in Exp. III. 3. All the experimental groups were significantly decreased compared with control group in AST, ALT and WBC. 4. NGF, BDNF and Trk B of spinal cord gray matter in all the experimental groups were increased compared with control group. Especially, Exp. III was more effective. 5. In histological observations, muscle contraction and denaturation of gastrocnemius muscle of all the experimental groups were inhibited. Especially, those of Exp. III was more effective. On the observations of liver and kidney, cell atrophy and apoptosis of all the experimental groups were decreased compared with control group. Especially, those of Exp. III was more effective. Conclusions : It can be suggested that YGKT and electrical acupuncture may improve motor behavior, EMG, hematological, histological and immunological findings in SCI-induced rats. Especially, combination of these two treatments will be somewhat better in spinal nerve recovery and motor function improvement.

• Journal of the Korean Society for Railway
• /
• v.17 no.3
• /
• pp.165-170
• /
• 2014

The resistance to motion of the Korean next-generation high-speed train (HEUM-430X) was assessed on the basis of 12 coasting test runs at coasting speeds up to approximately 380km/h. Two different methods, a linear regression method and a time-integral method, were employed to calculate decelerations from the time-velocity data and the time-distance data, respectively, and an equation of resistance to motion was devised from the deceleration data calculated at each time section. The effect of an improvement of the aerodynamic shape on the resistance to motion was investigated, with the results showing that the running resistance was reduced by about 15% due to these improvements. An increase of approximately 28% of the running resistance was also noted when running in a tunnel relative to running through an open field.