• Korean Journal of Metals and Materials
• /
• v.56 no.12
• /
• pp.861-869
• /
• 2018

To determine the origin of the inhomogeneous microstructure and texture observed in drawn and annealed high purity copper wires, two kinds of drawing process conditions and their influence was investigated. The regular condition, based on a symmetric die, and a condition designed intentionally to produce an inhomogeneous shear deformation using an asymmetric die were employed. The difference in intensity of <111>-<100> distributed texture between the two wires confirmed that the wire drawn under the asymmetric die condition experienced a higher amount of shear deformation. The extensive shear strain in the wire drawn under the asymmetric die condition gave rise to inhomogeneous primary and secondary recrystallization behavior. After annealing at $200^{\circ}C$, grains with <100> texture, which were larger than the surrounding recrystallized grains, were extensively present on one half circle of the wire drawn under the asymmetric die condition, while larger grains with <100> were sparsely observed around the middle region of the wire drawn under the regular condition. Interestingly, the area where the larger grains with <100> texture existed was identical to the area where the high shear strain occurred during drawing in both wires. During annealing at $400^{\circ}C$, grains with <112> texture started to grow abnormally at the center of both wires as a result of secondary recrystallization. After annealing at $900^{\circ}C$ grains with <112> due to secondary recrystallization occupied the entire region of the wire drawn under the regular condition. On the other hand, in the wire drawn under the asymmetric die condition and then annealed at $900^{\circ}C$, the <100> oriented grains as a result of the normal grain growth of the larger <100> grains which were observed after annealing at $200^{\circ}C$, coexisted with the abnormally grown <112> grains. These results indicate that dynamic recrystallization induced by the shear strain during drawing plays an important role in the inhomogeneity of the microstructure and texture of wires after annealing.

• Journal of Convergence for Information Technology
• /
• v.11 no.6
• /
• pp.33-39
• /
• 2021

Speech recognition technology is being combined with deep learning and is developing at a rapid pace. In particular, voice recognition services are connected to various devices such as artificial intelligence speakers, vehicle voice recognition, and smartphones, and voice recognition technology is being used in various places, not in specific areas of the industry. In this situation, research to meet high expectations for the technology is also being actively conducted. Among them, in the field of natural language processing (NLP), there is a need for research in the field of removing ambient noise or unnecessary voice signals that have a great influence on the speech recognition recognition rate. Many domestic and foreign companies are already using the latest AI technology for such research. Among them, research using a convolutional neural network algorithm (CNN) is being actively conducted. The purpose of this study is to determine the non-voice section from the user's speech section through the convolutional neural network. It collects the voice files (wav) of 5 speakers to generate learning data, and utilizes the convolutional neural network to determine the speech section and the non-voice section. A classification model for discriminating speech sections was created. Afterwards, an experiment was conducted to detect the non-speech section through the generated model, and as a result, an accuracy of 94% was obtained.

• Korean Journal of Food Science and Technology
• /
• v.53 no.3
• /
• pp.260-266
• /
• 2021

This study aimed to identify the hepatoprotective effects of a fermented Chrysanthemum indicum L. water extract. The extraction yield, antioxidant activities (ABTS and DPPH), and content of luteolin and luteolin-7-glucoside were significantly higher in the fermented C. indicum L. water extract (FCI) than in the C. indicum L. water extract. Treatment with FCI (200 ㎍/mL) significantly reduced the activities of gamma(γ)-glutamyl transferase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in HepG2 cells treated with 3% ethanol. Furthermore, FCI did not affect the viability of the HepG2 cells. These results suggest that FCI can be useful for the development of an effective hepatoprotective agent.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.16 no.2
• /
• pp.95-108
• /
• 2021

Technology innovation activities are very important for companies to secure technological competitiveness and continue to grow. Korea operates a certification system at the national level to promote corporate innovation activities, and strives to enhance SMEs' global technological competitiveness. Among these, the representative system related to technological innovation is the New Excellent Technology (NET) certification. NET is certified through a strict three-stage screening process, and is operated for the purpose of commercialization of new technology, technology trading, and promotion of early market entry by companies. Acquiring NET certification means that the company has a certain level of technological competitiveness. Therefore, this study attempted to conduct an empirical analysis on which technology innovation activities of companies affect the success of R&D projects and improvement of management performance, centering on NET certification system. To verify this, technology strategy, technology planning, systematic R&D process, internal cooperation, and external cooperation activities were set as major variables. As a result of the empirical analysis, it was confirmed that all variables set in this study individually contributed to the success of the R&D project and improvement of management performance. However, when looking at a comprehensive level that considers all variables, it was analyzed that systematic R&D process management and cooperation activities with external organizations have a statistically significant effect on R&D project success, and technology strategy establishment and technology planning activities, which are the initial stages of R&D, have a statistically significant effect on management performance. This study was conducted on innovation-oriented SMEs that have established and operated corporate R&D centers and are actively conducting R&D activities, and multiple regression analysis was used as an analysis method.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.24 no.5
• /
• pp.69-76
• /
• 2020

Global warming is a very important problem as it causes rapid climate change and natural disasters. Therefore, researches related to renewable energy are being actively conducted while promoting policies such as reducing carbon dioxide emission and increasing the proportion of renewable energy. Solar power generation is being applied in urban areas like BIPV as well as existing idle areas outside the city. Therefore, in this study, precast concrete blocks developed for paving roadways capable of solar power generation were designed and constructed. For the evaluation of field applicability for 6 months, skid resistance and block settlement were measured. As a result of the experiment, it was found that skid resistance satisfies the standard of general roadway in Korea, but not the standard of highway. The skid resistance tended to decrease as time passed. In addition, the settlement of the block gradually increased slightly, but it is much smaller than the allowable settlement of the roadway. Therefore, it is necessary to establish a maintenance period and method based on the periodic measurement results in the future.

• Journal of Korea Society of Industrial Information Systems
• /
• v.25 no.6
• /
• pp.47-54
• /
• 2020

The acupressure is a treatment that applies pressure to certain parts of the body and has been mainly used for pain relief in the field of oriental medicine. However, the treatment effect is often different depending on the practitioner's ability, experience, and physical strength, so standardized acupressure is needed. In this regard, the equipment is being released, but this is mainly a rolling massage method, which reduces energy concentration and poses a risk of injury. Therefore, in this study, a device that provides vertical acupressure based on variable bogie (wheel truck) was implemented. As a result of experimenting with load and body pressure distribution and desirability to validate the device's bearing pressure, the acupressure rod held up to 150kg, the body pressure ratio was measured lower than the body pressure ratio of the comparison item in section 0%

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.1
• /
• pp.67-72
• /
• 2022

Concrete prevents corrosion of reinforcing bars due to its strong alkalinity. However, in the sea, strong alkali components with a pH of 12 to 13 are eluted, which adversely affects the ecological environment and growth of marine organisms. In this study, the mechanical properties and durability of the low alkali mortar were evaluated for the development of a low alkali mortar for the 3D printed artificial reefs. As a result of evaluation of strength characteristics, the α-35 mixture, which were produced with fly ash, silica fume and α-hemihydrate gypsum, satisfied the strength requirement 27 MPa in terms of compressive strength. As a result of pH measurement, it was found that mixing with alpha-type hemihydrate gypsum resulted in minimizing pH due to the the formation of calcium sulfate instead of calcium hydroxide production. As a result of the chloride ion penetration resistance test, the α-35 mixture exhibited the best performance, 3844C. As a result of measuring the length change over time, the α-35 mixture showed the shrinkage 33.5% less compared to the Plain mix.

• Journal of Navigation and Port Research
• /
• v.46 no.3
• /
• pp.209-215
• /
• 2022

On the Jeju coast, international cruise ships, passenger ships, and other ships pass frequently, as well as many fishing boats. Thus, there is a high risk of marine accidents and frequent ship collisions. Accordingly, it is urgent to establish a coastal VTS for systematic safety management of ships passing through the coastal waters of Jeju. The purpose of this study was to set the area of the VTS to be newly established. In this study, to calculate the workload of the VTS operators, a formula was proposed that reflects the monitoring workload considering the monitoring frequency and required time for target as well as non-target ships and the workload for ship collision situations. The proposed formula was applied to the newly established VTS area in Jeju. Three control sectors were set up in each VTS center. The average number of workstations per hour was approximately 1, so the division between sectors was appropriate. Thus, it was deduced that there would be no workload for the VTS operators. It is expected that the method proposed in this study can be used as primary data for calculating the appropriate number of workstations for the current VTS, and setting the VTS area for a new coastal VTS in the future.

• Korean Journal of Remote Sensing
• /
• v.38 no.6_1
• /
• pp.1245-1255
• /
• 2022

Terra Nova Bay polynya (TNBP) is a representative coastal polynya in East Antarctica, which is formed by strong katabatic winds. As the TNBP is one of the major sea ice factory in East Antarctica and has a great impact on regional ocean circulation and surrounding marine ecosystem, it is very important to analyze its area change and development characteristics. In this study, we detected the TNBP from synthetic aperture radar (SAR) and optical images obtained from April 2007 to April 2022 by visually analyzing the stripes caused by the Langmuir circulation effect and the boundary between the polynya and surrounding sea ice. Then, we analyzed the area change and development characteristics of the TNBP. The TNBP occurred frequently but in a small size during the Antarctic winter (April-July) when strong katabatic winds blow, whereas it developed in a large size in March and November when sea ice thickness is thin. The 12-hour mean wind speed before the satellite observations showed a correlation coefficient of 0.577 with the TNBP area. This represents that wind has a significant effect on the formation of TNBP, and that other environmental factors might also affect its development process. The direction of TNBP expansion was predominantly determined by the wind direction and was partially influenced by the local ocean current. The results of this study suggest that the influences of environmental factors related to wind, sea ice, ocean, and atmosphere should be analyzed in combination to identify the development characteristics of TNBP.

• Korean Journal of Remote Sensing
• /
• v.38 no.6_2
• /
• pp.1643-1652
• /
• 2022

Deposited Marine Debris(DMD) can negatively affect marine ecosystems, fishery resources, and maritime safety and is mainly detected by sonar sensors, lifting frames, and divers. Considering the limitation of cost and time, recent efforts are being made by integrating underwater images and artificial intelligence (AI). We conducted a comparative study of You Only Look Once Version 5 (YOLOv5) and You Only Look Once Version 7 (YOLOv7) models to detect DMD from underwater images for more accurate and efficient management of DMD. For the detection of the DMD objects such as glass, metal, fish traps, tires, wood, and plastic, the two models showed a performance of over 0.85 in terms of Mean Average Precision (mAP@0.5). A more objective evaluation and an improvement of the models are expected with the construction of an extensive image database.