• 대기
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• 제31권4호
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• pp.445-459
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• 2021

This study uses a cloud-resolving storm simulator (CReSS) to understand the individual effect of determinant meteorological factors on snowfall characteristics in the Yeongdong region based on the rawinsonde soundings for two snowfall cases that occurred on 23 February (Episode 1) and 13 December (Episode 2) 2016; one has a single-layered cloud and the other has two-layered cloud structure. The observed cloud and precipitation (snow crystal) features were well represented by a CReSS model. The first ideal experiment with a decrease in low-level temperature for Episode 1 indicates that total precipitation amount was decreased by 19% (26~27% in graupel and 53~67% in snow) compared with the control experiment. In the ideal experiment that the upper-level wind direction was changed from westerly to easterly, although total precipitation was decreased for Episode 1, precipitation was intensified over the southwestern side (specifically in terrain experiment) of the sounding point (128.855°E, 37.805°N). In contrast, the precipitation for Episode 2 was increased by 2.3 times greater than the control experiment under terrain condition. The experimental results imply that the low-level temperature and upper-level dynamics could change the location and characteristics of precipitation in the Yeongdong region. However, the difference in precipitation between the single-layered experiment and control (two-layered) experiment for Episode 2 was negligible to attribute it to the effect of upper-level cloud. The current results could be used for the development of guidance of snowfall forecast in this region.

• 한국ITS학회 논문지
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• 제18권4호
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• pp.80-95
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• 2019

최근 들어 센서 및 통신기술의 발달로 국내외 연구자들은 장비나 시스템의 상태정보를 수집하여 진단 및 예측 기법을 통한 유지보수를 결정하는 방법론에 대해 연구를 활발히 진행하고 있다. 본 연구에서는 이러한 연구 문헌 고찰을 통해 현시점의 차량부품 상태를 바탕으로 미래 시점까지의 차량부품 상태변화 추이를 예측하여 유지보수 의사결정을 수행하는 시스템 프레임워크를 제시하였다. 또한, 유지보수 활동에 따른 전과 후의 차량부품 상태변화 추적을 통해서 상태 진단 및 예측 데이터 조정이 가능하도록 구성하였다. 향후 본 연구 결과의 적용을 통해 대중버스를 이용하는 시민들의 안전과 차량의 상태기반 유지보수 체계 활성화에 조금이나마 기여할 수 있기를 기대한다.

• Imaging Science in Dentistry
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• 제51권1호
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• pp.17-25
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• 2021

Purpose: This study was performed to investigate mandibular canal displacement in patients with ameloblastoma using a 3-dimensional mirrored-model analysis. Materials and Methods: The sample consisted of computed tomographic scans of patients with ameloblastoma (n=10) and healthy controls (n=20). The amount of mandibular canal asymmetry was recorded as a continuous variable, while the buccolingual (yaw) and supero-inferior (pitch) directions of displacement were classified as categorical variables. The t-test for independent samples and the Fisher exact test were used to compare groups in terms of differences between sides and the presence of asymmetric inclinations, respectively (P<0.05). Results: The length of the mandibular canal was similar on both sides in both groups. The ameloblastoma group presented more lateral (2.40±4.16 mm) and inferior (-1.97±1.92 mm) positions of the mental foramen, and a more buccal (1.09±2.75 mm) position of the middle canal point on the lesion side. Displacement of the mandibular canal tended to be found in the anterior region in patients with ameloblastoma, occurring toward the buccal and inferior directions in 60% and 70% of ameloblastoma patients, respectively. Conclusion: Mandibular canal displacement due to ameloblastoma could be detected by this superimposed mirrored method, and displacement was more prevalent toward the inferior and buccal directions. This displacement affected the mental foramen position, but did not lead to a change in the length of the mandibular canal. The control group presented no mandibular canal displacement.

• Journal of Veterinary Science
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• 제21권5호
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• pp.53.1-53.12
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• 2020

Background: The TightRope System is a device developed to provide extracapsular stabilization of the cranial cruciate ligament (CCL) rupture in canine stifles. I was then also employed for the extra-articular treatment of shoulder instability and for the intra-articular treatment of hip luxation in dogs and cats. Objectives: To evaluate the feasibility of the Mini-TightRope (mTR) System for the intraarticular treatment of CCL rupture in small breed dogs. Methods: A cadaveric canine model was used to record the steps of the surgical procedure. Five client owned dogs weighing from 8 to 10 kg and from 2 to 12 years of age were enrolled in the prospective study in which the mTR device was implanted in the stifle joint to replace the ruptured CCL. The dogs were graded using the Bologna Healing Stifle Injury Index (BHSII) and radiographic osteoarthritis (OA) scores. Results: The outcomes obtained at the time of the surgery (T0) and for the following 12 months (T12) showed an improvement in the functional parameters (BHSII from a median of 74.3 [range, 58.1-82.4] at T0 to 95.6 [range, 94.1-99.3] at T12]). The OA did not change in 3 dogs and increased by only 1 point in 2 dogs. Conclusions: In this preliminary study, the mTR was a successful and repeatable intraarticular surgical procedure for all dogs. Additional studies related to the clinical application of the technique in medium-large dogs should be encouraged.

• Wind and Structures
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• 제34권2호
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• pp.185-197
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• 2022

This study aimed to analyze the wind-induced mechanical energy (WME) of a proposed super high-rise and long-span transmission tower-line system (SHLTTS), which, in 2021, is the tallest tower-line system with the longest span. Anew index - the WME, accounting for the wind-induced vibration behavior of the whole system rather than the local part, was first proposed. The occurrence of the maximum WME for a transmission tower, with or without conductors, under synoptic winds, was analyzed, and the corresponding formulae were derived based on stochastic vibration theory. Some calculation data, such as the drag coefficient, dynamic parameters, windshielding areas, mass, calculation point coordinates, mode shape and influence function, derived from wind tunnel testing on reducedscale models and finite element software were used in calculating the maximum WME of the transmission tower under three cases. Then, the influence of conductors, wind speed, gradient wind height and wind yaw angle on WME components and the energy transfer relationship between substructures (transmission tower and conductor) were analyzed. The study showed that the presence of conductors increases the WME of transmission towers and changes the proportion of the mean component (MC), background component (BC) and resonant component (RC) for WME; The RC of WME is more susceptible to the wind speed change. Affected by the gradient wind height, the WME components decrease. With the RC decreasing the fastest and the MC decreasing the slowest; The WME reaches the its maximum value at the wind yaw angle of 30°. Due to the influence of three factors, namely: the long span of the conductors, the gradient wind height and the complex geometrical profile, it is important that the tower-line coupling effect, the potential for fatigue damage and the most unfavorable wind yaw angle should be given particular attention in the wind-resistant design of SHLTTSs

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.452-459
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• 2023

The core power control is an important issue for the study of dynamic characteristics in China initiative accelerator driven subcritical system (CiADS), which has direct impact on the control strategy and safety analysis process. The CiADS is an experimental facility that is only controlled by the proton beam intensity without considering the control rods in the current engineering design stage. In order to get the optimized operation scheme with the stable and reliable features, the variation of beam intensity using the continuous and periodic control approaches has been adopted, and the change of collimator and the adjusting of duty ratio have been proposed in the power control process. Considering the neutronics and the thermal-hydraulics characteristics in CiADS, the physical model for the core power control has been established by means of the point reactor kinetics method and the lumped parameter method. Moreover, the multi-inputs single-output (MISO) logical structure for the power control process has been constructed using proportional integral derivative (PID) controller, and the meta-heuristic algorithm has been employed to obtain the global optimized parameters for the stable running mode without producing large perturbations. Finally, the verification and validation of the control method have been tested based on the reference scenarios in considering the disturbances of spallation neutron source and inlet temperature respectively, where all the numerical results reveal that the optimization method has satisfactory performance in the CiADS core power control scenarios.

• Steel and Composite Structures
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• 제50권3호
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• pp.299-318
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• 2024

The main objective of this paper is to compute the far-field acoustic radiation (sound radiation) of functionally graded plates (FGM) loaded by sinusoidally varying point load subjected to the arbitrary boundary condition is carried out. The governing differential equations for thin functionally graded plates (FGM) are derived using classical plate theory (CPT) and Rayleigh integral using the elemental radiator approach. Four cases, segregated on power-law index k=0,1,5,10, are studied. A novel approach is illustrated to compute sound fields of vibrating FGM plates using the physical neutral surface with an elemental radiator approach. The material properties of the FGM plate for all cases are calculated considering the power law indexes. An in-house MATLAB code is written to compute the natural frequencies, normal surface velocities, and sound radiation fields are analytically calculated using semi-analytical formulation. Ansys is used to validate the computed sound power level. The parametric effects of the power law index, modulus ratios, different constituent of FGM plates, boundary conditions, damping loss factor on the sound power level, and radiation efficiency is illustrated. This work is the benchmark approach that clearly explains how to calculate acoustic fields using a solid layered FGM model in ANSYS ACT. It shows that it is possible to asymptotically stabilize the structure by controlling the intermittent layers' stiffness. It is found that sound fields radiated by the elemental radiators approach in MATLAB, ANSYS and literatures are in good agreement. The main novelty of this research is that the FGM plate is analyzed in the low-frequency range, where the stiffness-controlled region governs the whole analysis. It is concluded that a clamped mono-ceramic FGM plate radiates a lesser sound power level and higher radiation efficiency than a mono-metallic or metal-rich FGM plate due to higher stiffness. It is found that change in damping loss factor does not affect the same constituents of FGM plates but has significant effects on the different constituents of FGM plates.

• 한국균학회지
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• 제43권1호
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• pp.33-39
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• 2015

사상성 진균에서 veA 유전자와 연계되어 있는 velvet 복합체는 진균의 분화와 이차 대사산물의 조절에 매우 중요한 기능을 한다. 모델 사상균인 Aspergillus nidulans의 경우 methyltransferase인 VipB와 VipC를 포함한 여러 단백질들이 VeA 단백질과 상호작용하는 것으로 알려져 있다. 본 연구에서는 인간 기회감염 진균인 Aspergillus fumigatus에서 vipB와 vipC 유전자의 상동유전자를 분리하여 각각 AfuvipB와 AfuvipC로 명명하였다. AfuvipB 유전자는 AspGD 데이터베이스에 Afu3g14920으로 등록되어 있으며 1,510 bp 길이에 10개의 인트론을 가지고 있고, 유전자 산물은 336 아미노산 잔기로 구성된 단백질로 methyltransferase 도메인을 가지고 있었다. AfuvipC는 Afu8g01930으로 AfuvipB와 유사하게 10개의 인트론을 가지고 있으며 339개의 아미노산으로 구성된 methyltransferase를 암호화하고 있었다. A. fumigatus에서 각각의 유전자에 대한 기능을 알아보고자 유전자제거 돌연변이 균주들을 제조하고 그들의 표현형을 관찰하였다. AfuvipB 유전자 제거 돌연변이는 점 접종을 하였을 경우 대조군에 비하여 표현형의 차이를 보이지 않았다. 그러나 단일 포자에서 성장한 콜로니를 비교해 보았을 때 대조군에 비하여 그 크기가 작고 분화 속도도 약간 더딘 것을 관찰할 수 있었다. 반면에 AfuvipC 유전자 제거 돌연변이는 대조군과 비교하였을 때 표현형의 차이를 보이지 않았다. 이러한 결과는 두 개의 methyltransferase가 상호 중복적인 역할을 수행하거나 정상적인 실험실 배양조건에서는 중요한 기능을 수행하지 않을 수 있음을 시사한다.

• 전기학회논문지
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• 제67권5호
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• pp.635-643
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• 2018

This paper propose a method to identify the motor parameters and improve input voltage error which affect the low speed position error of the back-emf(back electromotive force) based sensorless algorithm and to secure the operation reliability and stability even in the case where the load fluctuation is severe and the start and low speed operation frequently occurs. In the model-based observer used in this paper, stator resistance, inductance, and input voltage are particularly influential factors on low speed performance. Stator resistance can cause resistance value fluctuation which may occur in mass production process, and fluctuation of resistance value due to heat generated during operation. The inductance is influenced by the fluctuation due to the manufacturing dispersion and at a low speed where the change of the current is severe. In order to find stator resistance and inductance which have different initial values and fluctuate during operation and have a large influence on sensorless performance at low speed, they are commonly measured through 2-point calculation method by 2-step align current injection. The effect of voltage error is minimized by offsetting the voltage error. In addition, when the command voltage is used, it is difficult to estimate the back-emf due to the relatively large distortion voltage due to the dead time and the voltage drop of the power device. In this paper, we propose a simple circuit and method to detect the voltage by measuring the PWM(Pulse Width Modulation) pulse width and compensate the voltage drop of the power device with the table, thereby minimizing the position error due to the exact estimation of the back-emf at low speed. The suitability of the proposed algorithm is verified through experiment.

• 한국산학기술학회논문지
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• 제19권7호
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• pp.337-342
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• 2018

도시유역에서 발생되는 내수침수를 방어하는 수단으로 구조적 대책인 빗물펌프장이 있으나 현실적 적용에 어려움이 있기 때문에 비구조적 대책 등이 보안되어야 한다. 본 연구에서는 빗물펌프장 실무운영 담당자의 의견을 반영한 최소의 월류량을 가지는 펌프의 최적운영수위를 결정하였다. 빗물펌프장의 최적운영수위를 산정하기 위해 최적화 기법인 GA(Genetic Algorithm)을 이용하였으며, 도시유역의 강우-유출 모형인 SWMM(Ver.5.1) DLL과 연계하였다. 제약조건으로는 펌프의 효율을 극대화하는데 까지의 걸리는 시간을 고려하였으며, 최적운영수위를 산정한 결과 전체적으로 기존운영수위보다 낮은 운영 수위에서 월류량이 감소하였다. 대부분 펌프의 경우 각 펌프 호기의 운영 범위에서 가장 낮은 운영 수위가 선정되었다. 초기 펌프의 운영하는 것이 월류량을 저감할 수 있는 것으로 판단되며 이 후 펌프 운영 조건 변경을 하여도 월류 저감에 변화는 없는 것으로 나타났다. 내수침수 저감정도는 약 1%~2%로 산출되었으며, 하류지역에서 발생되는 월류량을 저감하는 정도이지만, 펌프의 운영적 관점에서 기계적 및 실무적 관점의 접근에 따른 효과적인 운영이라 판단된다. 향후, 펌프의 운영조건 등을 고려한다면, 펌프의 효율을 증대하고 내수침수를 저감하는데 도움이 되리라 판단된다.