일반적으로 전기 패널은 용접이나 앵커링을 통해 기초에 설치된다. 콘크리트 기초-앵커 시스템에서 고려해야 할 열화 요인에 는 콘크리트 기초의 균열이 포함된다. 콘크리트 균열은 전기 패널의 앵커에 영향을 미치는 열화 현상 중 하나로 간주될 수 있다. 또한 독립반 및 열반된 전기 패널의 동적 특성은 상당히 다를 수 있다. 그러나 많은 연구자들이 하나의 전기 캐비닛 시편으로 진동대실험을 수행하였다. 따라서 열반 구성을 고려하여 동적 특성을 평가할 필요가 있다. 본 연구에서는 0.5 mm 및 1.0 mm 균열 폭을 고려하여 콘크리트 기초-앵커 시스템을 설계하였다. 콘크리트 기초-앵커 시스템을 진동대에 고정하고 1∼3개의 열반으로 구성된 단순화된 캐비 닛 모델을 설치하였다. 열반 수와 콘크리트 균열을 매개변수로 고려하여 진동대에 의한 공진주파수 검색 실험을 수행했으며 각 실험편 의 공진 주파수를 비교하였다.

Background: Stroke patients commonly experience functional declines in balance and gait due to decreased muscle strength and coordination issues caused by brain damage. Through repetitive training, robot-assisted gait training (RAGT) can aid in promoting neuroplasticity in stroke patients and help them acquire effective gait patterns. Additionally, convalescent rehabilitation hospitals help to ensure rapid recovery through intensive rehabilitation training. Objects: This study investigated the effects of RAGT frequency on gait and balance recovery in stroke patients in convalescent rehabilitation hospitals, providing data to optimize rehabilitation efficiency, enhance functional recovery, and support the development of personalized strategies to ensure safer and more rapid returns to daily life. Methods: This study compared the frequency of RAGT by analyzing a group receiving two units of RAGT per day for 5 days per week with a group receiving two units of RAGT per week as part of a comprehensive rehabilitation program, totaling 16 units daily, in a convalescent rehabilitation hospital. Results: In the 10-minute walking test, statistical significance was observed both within and between groups, whereas the Functional Ambulation Category, Fugl-Meyer Assessment–lower extremities, Berg Balance Scale, and timed up-and-go tests showed significance only within groups. Conclusion: End-effector RAGT and traditional gait training significantly improve gait ability, balance, and lower limb function in stroke patients.

This study compared and analyzed fish communities and mortality rates based on different survey methods (mesh size and retrieval frequency) of stationary nets, which are actively used in freshwater fish surveys in Korea, and proposed an appropriate survey method. Field surveys were conducted on the mainstream of the Nakdong River from May to June 2022 through a total of 10 times of fyke net surveys. The number of species and individuals collected varied significantly depending on the mesh size of the net (5 mm vs. 15 mm) (P<0.001), and larger species with an average total length of over 9 cm were mainly collected in the 15 mm mesh. However, the number of species (P=0.684) and individuals (P=0.100) collected did not show statistically significant differences depending on retrieval frequency (once/24 hours vs. twice/24 hours). In contrast, the mortality rate of fish differed based on all survey methods (mesh size, P<0.001; retrieval frequency, P<0.05), with mortality decreasing as the mesh size increased and retrieval frequency increased. Fyke nets are one of the standard fishing gears used in freshwater fish research in Korea, and to ensure species diversity, it is recommended to maintain the current standard mesh size of 5 mm. However, reducing the current 48-hour deployment time or increasing the retrieval frequency could lower the mortality rate. Furthermore, future research should focus on the differences in fish communities based on the combination of fishing gears commonly used in Korea to improve fish survey methodologies suitable for domestic freshwater environments.

This study aims to analyze the natural frequency characteristics of multi-cracked extensible beams. The model and governing equations of the multi-cracked beam were derived using Hamilton's principle while considering crack energy. The eigenmode functions were obtained through eigenvalue analysis by applying the patching conditions of the cracks, and the equations for the discretized cracked beam were formulated and solved. The displacement responses from nonlinear system analysis were used to calculate frequencies via Fast Fourier Transform (FFT), and the frequency characteristics were systematically analyzed with respect to the number of cracks, crack depth, and cross-sectional loss. Additionally, the natural frequencies and orthonormal bases of the linear system were derived by exploring the solutions of the characteristic equation reflecting the cracks. Numerical analyses showed that the natural frequency of a cracked extensible beam was higher than that of a cracked EB beam. However, as the number or depth of cracks increased, the natural frequency gradually decreased. Notably, in extensible beams with large deflections, the dynamic changes caused by cracks demonstrated results that could not be obtained through the EB beam model.

The performance of various types of silencers used to reduce the micropressure waves radiated from ventilation holes and inclined shafts, which are being studied as measures to reduce micropressure waves in railway tunnels, was evaluated to find an effective silencer. In order to find the optimal silencer, the magnitude and frequency characteristics of the pressure waves emitted from the inclined shaft were analyzed to find an excellent silencer. The evaluation showed that the model with a porous cylinder and a small diameter outer tube was the simplest but performed the best.

Cu-Ti thin films were fabricated using a combinatorial sputtering system to realize highly sensitive surface acoustic wave (SAW) devices. The Cu-Ti sample library was grown with various chemical compositions and electrical resistivity, providing important information for selecting the most suitable materials for SAW devices. Considering that acoustic waves generated from piezoelectric materials are significantly affected by the resistivity and density of interdigital transducer (IDT) electrodes, three types of Cu-Ti thin films with different Cu contents were fabricated. The thickness of the Cu-Ti thin films used in the SAW-IDT electrode was fixed at 150 nm. As the Cu content of the Cu-Ti films was increased from 31.2 to 71.3 at%, the resistivity decreased from 10.5 to 5.8 × 10-5 ohm-cm, and the density increased from 5.5 to 7.3 g/cm3, respectively. A SAW device composed of Cu-Ti IDT electrodes resonated at exactly 143 MHz without frequency shifts, but the full width at half maximum (FWHM) values of the resonant frequency gradually increased as the Cu content increased. This means that although the increase in Cu content in the Cu-Ti thin film helps to improve the electrical properties of the IDT electrode, the increased density of the IDT electrode deteriorates the acoustic performance of SAW devices.

In this article, improvement of heat screen failure for battle tank is proposed. The heat screen applied to protect a cam sensor from engine heat was cracked by vibrations generated in the engine. To solve this problem, the configuration of the heat screen was changed to a structure that can avoid engine vibration levels. The improved heat screen has first mode frequency at 4,000 RPM band outside the main operating range of the engine, and heat dissipation is at the same level as conventional heat screen. As a result, the improved heat screen secured reliability by improving vibration effects by approximately 163% while maintaining heat dissipation performance.

Accurate seismic vulnerability assessment requires high quality and large amounts of ground motion data. Ground motion data generated from time series contains not only the seismic waves but also the background noise. Therefore, it is crucial to determine the high-pass cut-off frequency to reduce the background noise. Traditional methods for determining the high-pass filter frequency are based on human inspection, such as comparing the noise and the signal Fourier Amplitude Spectrum (FAS), f2 trend line fitting, and inspection of the displacement curve after filtering. However, these methods are subject to human error and unsuitable for automating the process. This study used a deep learning approach to determine the high-pass filter frequency. We used the Mel-spectrogram for feature extraction and mixup technique to overcome the lack of data. We selected convolutional neural network (CNN) models such as ResNet, DenseNet, and EfficientNet for transfer learning. Additionally, we chose ViT and DeiT for transformer-based models. The results showed that ResNet had the highest performance with R2 (the coefficient of determination) at 0.977 and the lowest mean absolute error (MAE) and RMSE (root mean square error) at 0.006 and 0.074, respectively. When applied to a seismic event and compared to the traditional methods, the determination of the high-pass filter frequency through the deep learning method showed a difference of 0.1 Hz, which demonstrates that it can be used as a replacement for traditional methods. We anticipate that this study will pave the way for automating ground motion processing, which could be applied to the system to handle large amounts of data efficiently.

본 연구는 미래로 나아갈수록 창의적 인재가 요구되는 사회에서 청소년의 창의성을 어떻게 발현시키고 발달시킬 것인가에 대한 건강한 정신건강과 문화예술교육의 함의를 시사하고자 하였다. 본 연구의 연구 방법은 한국교육개발 원에서 제공하는 한국교육종단연구(KELS) 패널 데이터 자료를 부분 추출하여 SPSS 23.0 프로그램을 사용하여 정신 건강과 창의성의 관계를 살펴보았고 정신건강과 창의성의 관계에서 문화활동참여 빈도, 문화예술활동 경험 각각의 매개효과를 분석하였다. 연구 결과, 정신건강과 창의성의 관계는 유의미한 정적 관계로 나타났으며 부분매개효과를 확인했고 편안함, 즐거움, 행복함의 긍정적 정신건강과 문화예술교육, 문화예술활동이 청소년의 창의성에 긍정적인 영향을 미친다는 결과를 본 연구에서 검증하였다. 따라서 청소년의 창의성 발달을 위해 마음의 편안함, 즐거움, 행복 함과 같은 심리·정서적 정신건강 증진이 우선 되어야 하며 촉진 수단의 매개로 문화예술활동에 참여하는 방법을 활용할 수 있으며 청소년 문화예술활동 경험의 활성화를 위한 지역사회와 교육 현장의 다양한 문화예술교육 프로그램 개발 및 제공은 미래 사회의 창의융합형 인재를 양성하기 위한 주요한 과제가 될 것이다.

PURPOSES : The tire-pavement interaction noise (TPIN) comprises four sources, among which the tire tread vibration noise (TTVN) and air pumping noise (APN) are known to be the most influential. However, when evaluating TPIN, the noise level is estimated based on the overall noise, because general noise measurement methods cannot separate TTVN and APN. Therefore, this study aims to develop a method to separate TTVN and APN in TPIN for quantitative assessment of pavement noise. METHODS : Based on the results of our literature review and frequency band noise data measured in our study, we identified the dominant frequency ranges for TTVN and APN. Additionally, we evaluated TTVN and APN across various pavement types. RESULTS : TTVN was found to be dominant in frequency bands below 800 Hz, while APN was dominant in frequency bands above 800 Hz. Additionally, regardless of the vehicle type, vehicle speed, or pavement type, APN exhibited higher levels compared to TTVN. This result shows that APN has a more significant impact on TPIN than TTVN. CONCLUSIONS : The separation method of TTVN and APN proposed in this study can be utilized to quantitatively assess the relationship between the primary noise sources in TPIN and the characteristics of pavement texture in future research. Furthermore, it is anticipated that characteristics of low TPIN and optimal texture conditions can be proposed to mitigate TPIN, thus contributing to the development of lownoise pavements.

식물기생선충은 식물에 기생하여 식물의 생장을 저하시키거나 심할 경우 식물의 고사를 일으키는 주요 병원 체의 하나이다. 이들 선충은 수입 식물을 통해 국내로 유입될 수 있으며, 이로 인해 식물의 생장이 저하되거나 식물이 죽는 등의 실제적 피해를 야기할 수 있다. 생강은 한국의 대표 음식인 김치를 비롯한 다양한 요리와 음료, 전통약재 등에 사용되는 중요한 식약재료이며, 그 가치와 수요가 매우 높다. 최근 10년(2014-2023년) 동안 종구로 써 사용되는 재식용 생강의 수입량은 총 31,740톤이었는데, 수입 생강 원산지의 대부분은 중국으로써 최근 10년 간 수입량의 99.99%를 차지했다. 동기간 검역처분 내역은 합격 수량이 1,090건(27,637톤), 폐기 수량은 222건 (4,102톤)이었다. 폐기 처분을 받는 주용 원인을 분석해보면, 관리급 선충 검출이 139건, 종구에 흙이 부착된 경우 가 26건 등이었다. 앞으로도 농림축산검역본부는 수입 재식용 생강에 대한 실험실정밀검역을 통해 우리나라의 농업과 자연환경에 위해를 가할 수 있는 식물기생선충의 차단을 위해 최선의 노력을 다하고자 한다.

Background: Self-myofascial release using a foam roller has short-term effects for improving muscle function and joint range of motion (ROM) and reducing delayed onset muscle soreness (DOMS) after exercise. Objectives: The purpose of our study was to examine the muscle physiological changes for each set in self-myofascial release of the hamstring muscles using a foam roller in order to provide basic data for the most effective program composition for improving muscle tension, stiffness, and flexibility of the hamstring muscles. Design: A quasi-experimental clinical trial. Methods: To confirm the effect of self-myofascial release of the hamstring muscles using a foam roller, muscle tone and stiffness of the hamstring muscles were measured. As an intervention method, the study subject performed four sessions of self-myofascial release by moving a foam roller back and forth on the posterior thigh muscle of the right leg. Results: There were statistically significant changes in the stiffness of the biceps femoris and the flexibility of the hamstring muscles. Conclusion: Self-myofascial release with foam rolling is an effective intervention method for increasing hamstring flexibility and ROM, and it is recommended as effective to perform self-myofascial release for three to four sessions to maintain normal muscle tone and stiffness of the hamstring muscles.

This study investigated the effects of exposure frequency, depth of processing, and activity repetition types on vocabulary learning. In total, 78 South Korean fifth-grade students were divided into four conditions. Students in each condition were asked to read a passage with four of the eight target words (exposure: four times) and the other four words (exposure: once) for three days, and to perform the vocabulary activities assigned to each condition. According to the results, exposure frequency and activity repetition type had significant effects on vocabulary learning. Activity repetition type also had a significant interaction effect with exposure frequency and depth of processing. Notably, presenting a word 12 times (4x3) in reading intervals had a more positive impact on vocabulary learning than presenting it three times (1x3), particularly when different vocabulary activities were repeated. Meanwhile, when the same activity was repeated, an activity with a higher depth of processing was more effective for vocabulary learning.

Raman distributed temperature sensor can be used as temperature instruments as well as monitoring abnormalities in next-generation nuclear systems. Since noise reduction and Measuring Frequency enhancement are required, integration time adjustment has been mainly used so far. In this study, a new data processing method using Moving Average Filter was analyzed to see if noise reduction and Measuring Frequency could be reduced, and improvement measures were suggested.

Tb3+-doped CaNb2O6 (CaNb2O6:Tb3+) thin films were deposited on quartz substrates at a growth temperature of 300 °C using radio-frequency magnetron sputtering. The deposited thin films were annealed at several annealing temperatures for 20 min and characterized for their structural, morphological, and luminescent properties. The experimental results showed that the annealing temperature had a significant effect on the properties of the CaNb2O6:Tb3+ thin films. The crystalline structure of the as-grown CaNb2O6:Tb3+ thin films transformed from amorphous to crystalline after annealing at temperatures greater than or equal to 700 °C. The emission spectra of the thin films under excitation at 251 nm exhibited a dominant emission band at 546 nm arising from the 5D4 → 7F5 magnetic dipole transition of Tb3+ and three weak emission bands at 489, 586, and 620 nm, respectively. The intensity of the 5D4 → 7F5 (546 nm) magnetic dipole transition was greater than that of the 5D4 → 7F6 (489 nm) electrical dipole transition, indicating that the Tb3+ ions in the host crystal were located at sites with inversion symmetry. The average transmittance at wavelengths of 370~1,100 nm decreased from 86.8 % at 700 °C to 80.5 % at an annealing temperature of 1,000 °C, and a red shift was observed in the bandgap energy with increasing annealing temperature. These results suggest that the annealing temperature plays a crucial role in developing green light-emitting CaNb2O6:Tb3+ thin films for application in electroluminescent displays.

본 연구의 목적은 인지적 안녕감 수준에 따라 감정 경험에 차이를 보이는지 확인하고, 인지적 안녕감 수준을 강하 게 예측하는 대표적인 구체적 감정들이 무엇인지 확인함으로써 일상에서 사람들이 어떠한 감정을 관리하는 것이 전 체적인 삶의 만족도 증진에 효과적인지에 대한 실용적 방안을 모색하고자 함에 있다. 이를 위해 참가자간 요인설계 (between-subjects factorial design)를 채택하여 학부생 438명을 대상으로 인지적 안녕감 수준에 따른 감정 경험 빈도 를 측정하였다. 인지적 안녕감은 생활만족도 척도(SWLS)로 측정하였으며, 감정 빈도는 PANAS-X 척도로 측정하였고, 조사 후 인지적 안녕감의 평균값을 기준으로 집단을 나누어 감정 프로파일을 살펴보았다. 연구결과, 첫째, 인지적 안녕감이 높은 집단은 낮은 집단에 비해 전반적으로 긍정감정, 놀람감정의 경험빈도가 높았고 부정감정 경험빈도가 낮았다. 둘째, 인지적 안녕감에 영향을 미치는 대표적인 감정은 긍정 8개, 부정 7개, 놀람 1개임을 확인하였다. 특히 긍정은 ‘즐거운(happy)’, ‘자신감 있는(confident)’, 부정은 ‘나 자신에게 만족하지 못하는(dissatisfied with self)’, ‘나 자신이 역겨운(disgusted with self)’, 놀람은 ‘경탄을 자아내는(amazed)’ 감정이 인지적 안녕감에 가장 큰 영향력을 미쳤다. 본 결과를 통해 일상에서 경험하는 감정을 무조건 긍정-부정으로만 살펴볼 것이 아니라, 인지적 안녕감을 증진시키기 위해서는 특정한 감정들의 경험 빈도는 높이고(ex. 즐거움, 자신감), 특정한 감정의 경험 빈도는 줄이는 것(ex. 자신에 대한 불만족, 역겨움)이 더 효과적일 수 있음을 시사한다.

The purpose of this study was to analyse factors related to Home Meal Replacement (HMR) use among university students and to determine the dietary quality according to its consumption. A survey on the consumption of HMR and Nutrition Quotient (NQ) was conducted from September to November 2021. The study included 232 university students (88 males, 144 females) from Chungcheong. The proportion of consumption at least once a week was 71.55% for ready-to-eat foods, 55.60% for ready-to-cook foods, 40.95% for fresh-cut products, and 21.12% for meal-kits. The preference ratings were as follows: ready-to-eat foods, 3.77 out of 5 points, meal-kits, 3.53 points, fresh-cut products, 3.52 points, and ready-to-cook foods, 3.45 points. In terms of satisfaction, convenience (4.06 out of 5 points), taste (3.71 points), variety (3.67 points), and food hygiene (3.62 points) were rated the highest. The scores in the moderation NQ were significantly lower in the groups that consumed ready-to-eat foods (p=0.0002), ready-to-cook foods (p=0.0002), and meal-kits (p=0.0068) at least once a week compared to the groups that consumed them less than once a week. In conclusion, the results will serve as basic data for nutrition education for proper consumption of HMR among university students.