• Journal of Navigation and Port Research
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• v.42 no.1
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• pp.1-8
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• 2018

This study covers the selection of systems measuring the behaviour of the slender structure in the underwater environment and its performance assessment. From a comparison of an instrumentation system that can measure the continuous behaviour along the entire length of the slender structure, the underwater camera system is finally selected as the most appropriate semi-permanent measurement system for Deep-sea Ocean Engineering Basin of KRISO. An experiment on the rigid pipes for a basic performance evaluation of the underwater camera is conducted in this study. The motion of a top excited rigid pipe is measured with the utilization of the underwater camera system. The performance of the underwater camera is evaluated by comparing the movement of a pipe measured by the underwater camera with the measured input signals. Through the top excitation experiment for the slender structure, the real-time three-dimensional measurement of the underwater camera system is qualitatively evaluated in this case. The developed underwater camera system can apply to the system to measure dynamic behaviour of a slender structure and mooring line in Deep Ocean Engineering Basin.

• The Transactions of the Korea Information Processing Society
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• v.5 no.8
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• pp.2013-2026
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• 1998

In optical passive star interconnections, all packets are transmitted between nodes ina broadcast and-select manner. It is assumed that each node has a innable transmitter and a fixed-savelength receiver, ad that all packet lengths are equal so that each transmission can be done in a unit time. The tuning delay, denoted by $\delta$, means the amount of time for transmitter to change its wavelength to another one. The problec is , given ay value of the mumber of nodes N and the number of wavelengths $\kappa$ according to WDM implementations, to find transmission schedules with minimum cycle length for all-to all brondcaxt where no one sends any packet to itself. In this paper, we prove that the cycle length of optimal transcission schedules should be at least $max[[{\frac{N}{k}](N-1)}]$,$k\delta$$+N-1$. A novel algorithm for optimal transmission schedules is then presented when N-1 is divisible by $\kappa$. This algorithm also can be used for any values of N and $\kappa$ if the tuning delay $\delta$ does not affect strictly the cycle length of transmission schedules, i,e, $[\frac{N}{k}](N-1)$ > $\kappa\delta$+N-1.

• Membrane Journal
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• v.8 no.2
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• pp.77-85
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• 1998

To treat effectively EDIR (electrodeposition ion removal) wastewater in terms of CO$_{Mn}$ 1,500~2,000 ppm generated from aluminum painting process, a RO (reverse osmosis) process was designed and installed to recover and reuse the concentrated solvent sent back to the electrocodeposition tank while the permeate reused as rinse water. A RO system in which three polyamide-spiral wound modules ($102\Phi \times 1,016L$ mm) connnected in series had been running to treat 20 m$^3$ in waste volume in 3 days batch operation at the condition of system recovery of 30 %, applied pressure 11.5 $kg_f/cm^2$ and room temperature. During 42 hours continuous operation leading to 5-fold decrease in waste volume, nearly constant permeation flux of 390 l/m$^2$-hr was maintained and the permeate with average CO$_{Mn}$, 300 ppm was obtained which could be used for washing the remaining paint solution in ion-exchange tower instead of demineralized water. Also COD$_{Mn}$ rejection as a function of running time was observed to be in the range of 78~87 % and the observed solvent rejections for ethyl cellusolve, buthyl cellusolve and n-butanol were 79 %, 87 % and 70 %, respectively.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.231-240
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• 2018

Bamboo is one of the major biomass resources that have many advantages such as fast growing, easy cultivation, short rotation, and a relatively lower price. In this study, the anatomical characteristics of Moso bamboo (Phyllostachys pubescens) by age from one-year-old to five-year-old were examined by optical and scanning electron microscopy. Also, the crystalline properties such as relative crystallinity and crystallite width were investigated by an X-ray diffraction method. In one-year-old bamboo xylem, a few vascular bundles showed missing bundle sheath in near the intercellular space. Moreover, one-year-old bamboo had the shortest fiber length and the smallest values in vessel diameter, width of vascular bundle, and thickness of inner layer. One-year-old bamboo also showed the smallest values in the crystallinity and crystallite width. Near epidermis samples had longer fiber length and greater vascular bundle spacing than near pith samples. Relative crystallinity and crystallite width near the epidermis were also higher than near the pith. This study revealed significant differences in qualitative and quantitative anatomical characteristics between one-year-old and two-year- or more old Moso bamboos. It is concluded that the structural differences by bamboo age can be used to differentiate the characteristics of juvenile and mature bamboo.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.72-72
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• 2019

This study compared the growth characteristics of A. gigas according to the transplanting season, in the cultivation located in Yeongju, Gyeongsangbuk-do, transplanted in the autumn and spring. As a result of that the plant survival rate were observed the highest autumn transplanting (9.4%; autumn-92.2%, spring-82.8%) and bolting rate were observed lowest spring transplanting (7.1%; autumn-37.3%, spring-30.2%). Growth characteristics (height, leaf length and width, stem diameter) were observed the highest autumn transplanting in June and highest spring transplanting in August. The early growth is high growth due to long rooting time in autumn transplanting, but the difference in the ground growth between the two experiments was insignificant when the main growth period was from June to August. Further analysis of the growth characteristics and marker components of roots of A. gigas can be used to determine the optimal planting time and the establishment of high quality cultivation technology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.224-229
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• 2018

Korea is experiencing a rapid increase in electricity consumption due to rapid economic development, and many power transmission towers are installed to provide smooth power supply. The high-voltage transmission line is mainly made of aluminum stranded wire, and the wire is loosely guided so that some deflection is maintained. The degree of deflection has a great influence on the quality of the construction and the life of the cable. As the time passes, the shrinkage and expansion occur repeatedly due to the weight of the cable and the surrounding environment. Therefore, periodic monitoring is essential for the management of the power transmission line. In this study, the power transmission lines were monitored using 3D laser scanning technology. The data of the power transmission line of the study area was acquired and the point cloud type 3D geospatial information of the transmission line was extracted through data processing. The length of the transmission line and deflection amount were calculated using the 3D geospatial information of the transmission line, and the distance from the surrounding obstacles could be calculated effectively. The result of study shows the utilization of 3D laser scanning technology for transmission line management. Future research will contribute to the efficiency of transmission line management if a transmission line monitoring system using 3D laser scanning technology is developed.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.34-42
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• 2019

The existence of different thermodynamic properties results in various undesirable effects, such as thermal deformation and residual stress, in heat-welding processes. The solid-state junction, by using explosive or electromagnetic forces, i.e., high-velocity impact welding without employing heat is advantageous in joining materials with different thermodynamic properties. In the solid-state junction, the joining is performed within a short time, a high velocity and large deformations are accompanied by interfacial surfaces. The numerical analysis models play an important role in the understanding of the mechanism of high-velocity impact welding. However, in the analysis of high velocity and large deformations, the conventional Lagrangian method has low reliability due to the occurrence of entanglements. In this study, high-velocity impact welding between Cu and CP-Ti with different thermodynamic properties was performed using a un-gridded numerical method, SPH (Smoothed Particle Hydrodynamics), and interfacial morphology occurred. As a result of the analysis, the interfacial morphology was confirmed and the compared degree of shape (straight, vortex), period, length, and so on appeared differently depending on the relationship between the parameters (impact angle and speed).

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.181-190
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• 2022

In this paper, we use a LiDAR sensor and an image camera to detect a left-turning waiting vehicle in two ways, unlike the existing image-type or loop-type left-turn detection system, and a left-turn traffic signal corresponding to the waiting length of the left-turning lane. A system that can efficiently assign a system is introduced. For the LiDAR signal transmitted and received by the LiDAR sensor, the left-turn waiting vehicle is detected in real time, and the image by the video camera is analyzed in real time or at regular intervals, thereby reducing unnecessary computational processing and enabling real-time sensitive processing. As a result of performing a performance test for 5 hours every day for one week with an intersection simulation using an actual signal processor, a detection rate of 99.9%, which was improved by 3% to 5% compared to the existing method, was recorded. The advantage is that 99.9% of vehicles waiting to turn left are detected by the LiDAR sensor, and even if an intentional omission of detection occurs, an immediate response is possible through self-correction using the video, so the excessive waiting time of vehicles waiting to turn left is controlled by all lanes in the intersection. was able to guide the flow of traffic smoothly. In addition, when applied to an intersection in the outskirts of which left-turning vehicles are rare, service reliability and efficiency can be improved by reducing unnecessary signal costs.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.69-69
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• 2020

식물체가 건조 스트레스를 받으면 각 기관 물질 생산의 변이, 분화 및 발달 억제를 통해서 식물의 생산활동을 현저히 저하시켜, 식물의 생장, 형태, 개체발생 및 대사생리에 영향을 미치는 것으로 연구되어 왔다. 최근 기후 온난화로 인해 온도가 점진적으로 상승하고 가뭄과 같은 이상기상이 빈번하게 발생함에 따라 많은 노지 작물의 농업 생산성이 약화되고 있다. 배추는 우리나라의 대표적인 식품 중 하나인 김치의 주재료로 연중 안정적인 생산과 공급이 필요시 되지만, 배추의 경우 건조 조건에서 엽육조직의 붕괴와 같은 생리장해가 발생되기 때문에 최근 발생되고 있는 이상 기후의 영향으로 안정적인 생산이 어려워지고 있는 실정이다. 하지만, 배추에서는 이상 기후에 대응이 가능한 내건성 품종의 육성을 위한 연구는 미흡한 실정이다. 따라서 본 연구에서는 내건성이 높은 배추 개발을 위한 기초소재를 찾는 것을 목적으로 농촌진흥청 유전자원센터에서 보존하고 있는 재래종 배추 30계통을 분양받아 강릉원주대학교 생명과학대학 내의 조직배양실을 이용하여 연구를 수행하였다. 배지는 Tissue Culture Square Dish(125×125×20mm)에 Agar를 녹여 40ml씩 분주하여 고체배지를 조성한 후, 건조 처리구 Polyrthylene glycol 6000(PEG) 0%(Control), 20%(Mild Stress), 30%(Severe Stress)를 설정하여 60ml씩 추가 분주하여 배양기 28℃에서 15시간 처리를 하였다. 분양받은 각 계통의 종자는 1% 차아염소산 나트륨으로 10분간 종자표면을 살균한 후, 5번 정도 멸균수로 헹군 후, 표면 살균한 재래종 종자를 고체배지 시험관에 6립씩 치상하였다. 식물체 생육은 각 처리구별 3반복으로 하였으며 주간 12시간 주기, 광도 2,400Lux, 온도 20℃의 조직배양실에서 치상 후 7일간 생육하였다. 치상 후 7일간 생육시킨 식물체를 채취하여 지상부생체중, 지하부 생체중, 뿌리 길이를 측정하였으며, 지상부와 지하부로 나누어 50℃에서 72시간 건조시킨 후, 건물 생산량을 조사하였다. 본 실험 결과 건조 처리(PEG-6000)는 배추의 생장을 저해하였지만, 생육 저해 정도는 계통간의 차이가 있는 것을 관찰할 수 있었으며 무처리구와 스트레스 처리구간의 생장량 변화 정도를 기반으로 군집분석을 수행한 결과 'IT110483'과 'IT104903' 계통이 실험에 공시된 계통들 중 상대적으로 강한 건조 내성을 가진 것을 확인할 수 있었다. 따라서, 재래종 배추 계통 중 일부는 건조내성이 강한 새로운 배추 품종을 육성하는데 있어 유용하게 이용될 수 있을 것으로 사료된다.

• Phonetics and Speech Sciences
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• v.15 no.4
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• pp.45-51
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• 2023

Voice issues such as voice weakness that arise with age can have social and emotional impacts, potentially leading to feelings of isolation and depression. This study aimed to investigate the changes in acoustic characteristics resulting from aging, focusing on voice quality and spoken fluency. To this end, tasks involving sustained vowel phonation and paragraph reading were recorded for 20 elderly and 20 young participants. Voice-quality-related variables, including F0, jitter, shimmer, and Cepstral Peak Prominence (CPP) values, were analyzed along with speech-fluency-related variables, such as average syllable duration (ASD), articulation rate (AR), and speech rate (SR). The results showed that in voice quality-related measurements, F0 was higher for the elderly and voice quality was diminished, as indicated by increased jitter, shimmer, and lower CPP levels. Speech fluency analysis also demonstrated that the elderly spoke more slowly, as indicated by all ASD, AR, and SR measurements. Correlation analysis between voice quality and speech fluency showed a significant relationship between shimmer and CPP values and between ASD and SR values. This suggests that changes in spoken fluency can be identified early by measuring the variations in voice quality. This study further highlights the reciprocal relationship between voice quality and spoken fluency, emphasizing that deterioration in one can affect the other.