Researching and estimating the ecological characteristics of target fish species is crucial for fisheries resource management. The results of these estimates significantly influence stock assessments and management reference points such as size limit and closed seasons. Recently, ecological characteristics have been changing due to overfishing, climate change, and marine pollution, making continuous estimation and monitoring essential. This study analyzed the ecological changes in small yellow croaker (Larimichthys polyactis) resources in Korea over 24 years (2000-2023) using biological data (growth and gonad traits). By estimating the annual length-weight relationship and length at maturity (L50 and L95), we interpreted the numerical trends of early maturation due to resource depletion. The parameter b of the length-weight relationship, indicating the nutritional status of the resources, showed a slight increase over the years, suggesting relatively good nutritional status (b > 3.0) during most periods. Trend analysis between length at maturity and biomass indicated that as biomass decreased, maturity length also decreased.
In recent automated manufacturing systems, compressed air-based pneumatic cylinders have been widely used for basic perpetration including picking up and moving a target object. They are relatively categorized as small machines, but many linear or rotary cylinders play an important role in discrete manufacturing systems. Therefore, sudden operation stop or interruption due to a fault occurrence in pneumatic cylinders leads to a decrease in repair costs and production and even threatens the safety of workers. In this regard, this study proposed a fault detection technique by developing a time-variant deep learning model from multivariate sensor data analysis for estimating a current health state as four levels. In addition, it aims to establish a real-time fault detection system that allows workers to immediately identify and manage the cylinder’s status in either an actual shop floor or a remote management situation. To validate and verify the performance of the proposed system, we collected multivariate sensor signals from a rotary cylinder and it was successful in detecting the health state of the pneumatic cylinder with four severity levels. Furthermore, the optimal sensor location and signal type were analyzed through statistical inferences.
San-ja is one of the main members consisting of the roof of traditional wooden buildings in Korea. In this study, the regional characteristics of the materials used in San-ja and changes of the materials over time were examined. To this end, 123 documents on the repair of wooden architectural heritage recorded since the 1950s were reviewed. It was found that there was a difference in the San-ja material by region because of the diversity in the conditions of material supply. For instance, bamboo was the most frequently used material in Jeollanam-do province because it was readily available. However, with the development of transportation and vehicle, the regional characteristics have disappeared. As a result, the material has been unified with bamboo now. This is because bamboo is specified as a representative material in the specification or the convenience of construction is prioritized. In addition, the social and economic conditions at the time of repair had an influence on the selection of the San-ja materials.
Yekeo Yuhae vocabulary has 62 categories, including 4651 Chinese words. We think these words, with the characteristics of the same time, systematicness and richness are active in the late Ming and early Qing Dynasties. We searched five vocabulary categories, including 544 Chinese words, finding Chinese words in Yekeo Yuhae mainly from Ancient Chinese times, Middle Chinese period and period of Tang Song and Yuan Dynasties. The amount of words coming from the Ming and Qing Dynasties is the least, which reflects the inheritance and stability of the vocabulary
품종별 수확시기에 따른 떫은 감의 품질변화를 분석하고 이를 이용한 곶감제조를 통해 고품 질의 곶감 생산을 위한 곶감의 식품학적 특성을 분석 하였다. 고품질의 곶감 생산을 위해서는 품종별 떫은 감의 적절한 선택과 적정숙도를 갖춘 과육을 선별하는 것이 매우 중요하다. 미숙과의 경우 수분함 량, 색도값이 적숙과 및 완숙과에 비해 낮은 값을 보인 반면 경도는 높게 나타났다. 고품질의 곶감의 생 산하기 위해서는 최소한 적황색 혹은 녹황색인 적숙과 이상의 떫은 감을 사용해야 한다.
본 연구는 중고령자 고용에서 중요한 비중을 차지하고, 최근 증가하는 경향을 보이는 중고령 여성 시간제 일자리의 질을 향상시키기 위하여 기존의 시간제 일자리 연구에서 간과되었던 중고령 여성의 시간제 일자리 특성을 분석하였다. 이를 위하여 시간제 일자 리 중고령 여성의 인구사회학적 특성을 파악하고, 시간제 일자리의 직업 특성과 근로여 건 특성을 국민노후보장패널 4차(2011년) 자료를 통해 분석하였다. 연구결과, 시간제 일자리 중고령 여성은 인구사회학적 특성 면에서 상당히 취약하였으며, 시간제 일자리는 업종과 직종, 종사상 지위, 정규직 여부, 임금, 근속기간, 고용안정성과 국민연금, 고용보험, 산재보험의 사회보험제도 가입율 면에서 전일제 일자리와 유의미한 차이를 보였고, 일자리의 질이 훨씬 낮은 것을 확인할 수 있었다. 이러한 연구결 과를 토대로 중고령 여성 시간제 일자리의 질 개선을 위한 시사점을 제시하였다.
본 실험은 볏짚 수거시기에 따른 물리적 특성, 사료가치, 소화율 및 기호성에 미치는 영향을 구명하기 위하여 볏짚 수거시기를 9처리 3반복(T1: 벼 수확 후 10일, T2: 벼 수확 후 25일, T3: 벼 수확 후 40일, T4: 벼 수확 후 51일, T5: 벼 수확 후 70일, T6: 벼 수확 후 85일, T7: 벼 수확 후 100일, T8: 벼 수확 후 115일, T9: 벼 수확 후 130일)으로 하여 2007년 10월부터 2008년 2월까지 경북대
최근까지도 많은 시간이력 지진해석이 연약지반의 증폭영향을 고려하지 않고 연약지반 위 지표면에서 기록된 지진거동으로 수행되었다. 그러나 합리적인 구조물의 지진해석을 위해서는 지반조건을 고려하고 암반지진기록을 이용하는 것이 중요하다. 이 연구에서는 연구를 위해 태평양지진연구센터(PEER)에서 제공하는 공개된 1557개의 지진기록 중에서 26개 암반지진기록을 선정하고 암반지진 기록의 특성을 분석하였다. 연구결과에 의하면, 지반조건을 고려하지 않고 지진규모로부터 지진가속도를 추정하는 것은 합리적이지 못하며, PEER 데이터베이스 암반지진기록으로는 지진가속도, 지진규모, 진앙거리 사이의 일반적인 상관관계를 추정하는 것도 어려운 것으로 평가되었다. 그러나 이 연구에서 선정한 26개 암반지진기록은 구조물-지반체계의 시간이력 지진해석을 위해 암반지진기록으로 사용할 수는 있지만, 이 지진기록을 사용할 때에도 지진가속도, 지진규모, 진앙거리 및 지반조건이 유사한 지진기록을 사용하는 것이 필요하다는 것을 확인할 수 있었다.
A* algorithm is a global path generation algorithm, and typically create a path using only the distance information. Therefore along the path, a moving vehicle is usually not be considered by driving characteristics. Deceleration at the corner is one of the driving characteristics of the vehicle. In this paper, considering this characteristic, a new evaluation function based path algorithm is proposed to decrease the number of driving path corner, in order to reduce the driving cost, such as driving time, fuel consumption and so on. Also the potential field method is applied for driving of UGV, which is robust against static and dynamic obstacle environment during following the generated path of the mobile robot under. The driving time and path following test was occurred by experiments based on a pseudo UGV, mobile robot in downscaled UGV’s maximum and driving speed in corner. The experiment results were confirmed that the driving time by the proposed algorithm was decreased comparing with the results from A* algorithm.