A compact vibratory bowl feeder system is proposed to transport lightweight annular film components. Vibration analysis was conducted to calculate its natural frequencies, and the motion characteristics of the bowl and transported parts were analyzed under resonance excitation at varying supply voltage levels. The natural frequencies of the proposed system were found to be 157Hz, 249Hz, and 505Hz. At these resonance frequencies, significant rotational vibrations occurred, while vertical vibrations were relatively small. Especially at 505Hz, bending of the leaf spring caused large rotational motion of the bowl. The part feeding speed increased linearly with the applied voltage, reaching 4mm/sec at 100V and 18mm/sec at 200V. At 157Hz and 249Hz excitation frequencies, large rotational and vertical vibrations were observed, respectively. Under rotational vibration, the parts moved forward via jumping motion when the bowl's velocity amplitude was relatively large, or via slipping when smaller. Minor backward slipping was also observed. Under vertical vibration, parts exhibited forward jumping motion without back-and-forth slipping.

이 논문은 소비자 설문조사를 통해 여름철 대표 과일인 수박과 참외의 소비자 구매 행태와 구매 빈도에 영향을 미치는 요인을 분석하여 수박·참외 산업의 지속 가능한 발전 방향을 탐구하고자 하였다. 소비자 구매 행태를 분석하고, 구매 빈도에 영향을 미치는 주요 요인을 규명하기 위해 순위형 로짓 분석을 실시하였다. 연구 결과에 따르면 수박은 맛, 외형이 가격보다 더 중요한 요소로 나타나, 고당도 수박 생산, 품종 개선 및 유통 방식 개선의 필요성이 제기되었다. 참외는 맛, 신선도, 외형이 구매시 중요한 요소로 분석되었으며, 고령층 소비자에 비해 젊은층 선호도가 상대적으로 낮아 참외 시장 확대를 위해서는 다양한 소비 계층이 관심을 가질 수 있는 차별화된 판매 전략이 필요하다는 점을 시사하였다.

본 연구는 신속보기 기반 안구운동 과제에서 시선추적 장비의 샘플링 주파수가 시선의 이동 및 고정 지표와 반응 분류 성능에 미치는 영향을 규명하고자 하였다. 고령 성인 30명을 대상으로 정방향과 역방향의 혼합형 신속보기 과 제를 수행하는 동안 기준 주파수인 300Hz로 수집된 시선 데이터를 30∼200Hz 범위로 다운샘플링하여 분석하였다. 조건별 안구운동 주요 지표 분석 결과, 샘플링 주파수가 감소함에 따라 잠복기는 27ms 이상 증가하였고, 이동크기는 2∼3deg, 최대속도는 90∼120deg/s 감소하였다. 시선고정 지속시간은 최대 397ms 증가하였으며, 위치 분산은 정방향에서 약 3배, 역방향에서 최대 10배 증가하였다. 반면, 시표적과의 위치 오차는 큰 변동 없이 유지되었다. 안구운동 반응 분류 성능 비교 결과, 샘플링 주파수 90Hz 이상에서는 정확도 .98, 정밀도 .99, F1 점수 .99, 일치도 계수 .95 이상을 유지하였으나, 60Hz 이하에서는 F1 점수가 .91 이하, 일치도 계수는 .63 이하로 급격히 저하되었다. 본 연구 결과는 신속보기 안구운동 연구에서 시선추적 장비의 샘플링 주파수가 분석 정확도와 신뢰도에 실질적인 영향을 미 친다는 점을 시사하며, 300Hz 기준의 시선 데이터 분석 수준을 안정적으로 유지하기 위해서는 최소 90Hz 이상의 샘플링 주파수 확보가 필요함을 제안한다.

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.

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.

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.

In this research, we examined the shifts in determinants influencing the frequency of eco-friendly food purchases pre- and post-COVID-19. Our analysis utilized filtered 2019-2021 Consumption Behavior Survey data from the Korea Rural Economic Institute Food, excluding any irrational responses. Given the nature of the dependent variable, a multinomial logistic regression model was employed with demographic factors, variables pertaining to food consumption behavior, and variables concerning food consumption awareness as predictors. Following the onset of the COVID-19 pandemic, an individual's level of education was observed to positively influence the frequency of eco-friendly food purchases. In contrast, income level and fluctuations in food consumption expenditure did not appear to have a discernible impact on the purchasing frequency of such eco-friendly products. Irrespective of the advent of COVID-19, variables such as the frequency of online food purchases, the utilization of early morning delivery services, dining out frequency, and the intake of health-functional foods consistently demonstrated a positive correlation with the propensity to purchase eco-friendly foods. Overall, consumers prioritizing safety, quality, and nutrition over price, taste, and convenience in their procurement decisions for rice, vegetables, meat, and processed foods exhibit an increased inclination toward the acquisition of eco-friendly food products.

This study applied the text frequency method to analyze the crops prevalent during the Chosunwangjoshilrok dynasty, and categorized the results by each king. Contemporary perception of grains was observed by examining the staple crop types. Staple species were examined using the word cloud and semantic network analysis. Totally, 101,842 types of crop consumption were recorded during the Chosunwangjoshilrok period. Of these, 51,337 (50.4%) were grains, 50,407 (49.5%) were beans, and 98 (0.1%) were seeds. Rice was the most frequently consumed grain (37.1%), followed by pii (11.9%), millet (11.3%), barley (4.5%), proso (0.8%), wheat (0.6%), buckwheat (0.1%), and adlay (0.05%). Grain chronological frequency in the Choseon dynasty was determined to be 15,520 cases in the 15th century (30.2%), 11,201 cases in the 18th century (21.8%), 9,421 cases in the 17th century (18.4%), 9,113 cases in the 16th century (17.8%), and 6,082 cases in the 19th century (11.8%). Interest in grain amongst the 27 kings of Choseon was evaluated based on the frequency of records. The 15th century King Sejong recorded the maximum interest with 13,363 cases (13.1%), followed by King Jungjo (8,501 cases in the 18th century; 8.4%), King Sungjong (7,776 cases in the 15th century; 7.6%).

본 연구에서는 우리나라에 태풍이 내습할 때 먼저 피해를 받는 남해안 지역을 대표하는 Quantile을 제안하고, 각 지점들의 재 현기간에 따른 극치 풍속을 추정하기 위하여 연 최대풍속 자료와 Hosking이 제안한 선형-모멘트 방법(L-moments)을 이용한 지역빈도 해석을 수행하였다. 모든 기상관측 지점에서는 비정상적인 값이 존재하지 않았고 이질성 검정을 통해서 하나의 동질 한 지역을 나타 낼 수 있음을 확인하였다. 또한 적합도 과정을 통해서 Generalized Normal (GNO) 및 Generalized Extreme Value(GEV) 분포를 남해안 지역을 대표하는 빈도분포로 선택하였다. 상대 오차(RB)와 상대 평균제곱근 오차(RRMSE)를 이용하여 두 분포의 안정성을 평가한 결 과, GNO 분포가 GEV 분포보다 더 안정한 것을 알 수 있었다. 마지막으로 남해안 지역을 대표하는 Quantile과 각 지점들의 평균, 중앙 값, 그리고 위치 매개변수를 이용하여 지점들의 극치 풍속을 추정하였다. 본 연구에서 적용한 지역빈도해석이 자료가 부족하거나 계측 되지 않은 지점들에 대한 극치 풍속을 추정하기 위한 방법으로서 도입이 필요하다고 생각된다.

This paper takes six Chinese Textbooks in the late Korean Dynasty compiled by Wang Weihui and others as the research object, selects and counts the high-frequency words, and analyzes their characteristics from the aspects of syllable number, part of speech, use in modern Chinese, meaning content, dialect background and so on. It is found that only monosyllabic words and disyllabic words appear in the high-frequency words in the late Korean Chinese textbooks, and the parts of speech are mainly verbs and nouns. Modern Chinese uses some words of high-frequency words, and some high-frequency words are no longer used. In terms of meaning and content, high-frequency words are highly related to commercial and trade activities. At the same time, there are some spoken words and a large number of northeast dialect words.

The purpose of this study was to estimate the influence of the determinants for home meal replacement (HMR) purchase frequency before and after COVID-19. Multinomial logistic regression was applied to the 2018~2020 Consumer Behavior Survey for Food data from the Korea Rural Economic Institute (KREI). Gender, age, number of households, monthly income, use of eating out, delivery and takeout order service, HMR food safety concern, the frequency of cooking at home, grocery shopping, and eating alone were applied as the explanatory variables to explain HMR purchase frequency. The results are as below. Compared to the previous year, the growth rate of HMR purchase frequency in 2020 was relatively high, indicating that the COVID-19 outbreak acted as a catalyst. Unlike in 2018 and 2019, there was no statistical difference in the HMR purchase frequency between single- and multi-person households in 2020, with indicating multi-person households began to emerge as one of the major HMR consumption groups. Unlike 2018, the 2020 HMR purchase frequency showed a statistically positive relationship with those of grocery shopping and eating alone. There was a positive relationship between the frequency of eating out/food delivery orders and HMR purchases. The more often cooking at home occurred, the less HMR food was purchased.

Nuclear power plants in Korea were designed and evaluated based on the NRC's Regulatory Guide 1.60, a design response spectrum for nuclear power plants. However, it can be seen that the seismic motion characteristics are different when analyzing the Gyeongju earthquake and the Pohang earthquake that has recently occurred in Korea. Compared to the design response spectrum, seismic motion characteristics in Korea have a larger spectral acceleration in the high-frequency region. Therefore, in the case of equipment with a high natural frequency installed in a nuclear power plant, seismic performance may be reduced by reflecting the characteristics of domestic seismic motions. The failure modes of the equipment are typically structural failure and functional failure, with an anchorage failure being a representative type of structural failure. In this study, comparative analyses were performed to decide whether to consider the inelastic behavior of the anchorage or not. As a result, it was confirmed that the seismic performance of the anchorages could be increased by considering the inelastic behavior of an anchorage.

Seismic qualification of instruments and devices mounted on electrical cabinets in a nuclear power plant is performed in this study by means of the in-cabinet response spectrum (ICRS). A simple method and two rigorous methods are proposed in the EPRI NP-7146-SL guidelines for generating the ICRS. The simple method of EPRI can give unrealistic spectra that are excessively conservative in many cases. In the past, the time domain analysis (TDA) methods have been mostly used to analyze a structure. However, the TDA requires the generation of an artificial earthquake input motion compatible to the target response spectrum. The process of generating an artificial earthquake may involve a great deal of uncertainty. In addition, many time history analyses should be performed to increase the accuracy of the results. This study developed a numerical analysis program for generating the ICRS by frequency domain analysis (FDA) method. The developed program was validated by the numerical study. The ICRS calculated by FDA thoroughly matched with those obtained from TDA. This study then confirms that the method it proposes can simply and efficiently generate the ICRS compared to the time domain method.