• 대한기계학회논문집
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• 제17권8호
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• pp.2061-2068
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• 1993

Condition monitoring technology is of great importance for the maintenance of complex machinery in view of its early monitoring of the abnormal condition and the protection against failure. Several methods have been used for the detection of failure of journal bearings, one of the main elements of mechanical system. The methods most frequently used are vibration and temperature monitoring, but these are unable to monitor the wear conditions exactly. In this study, an ultrasonic measument method, one of the non-destructive testing methods, was introduced as the monitoring technology. Furtermore a pattem recognition method was applied to analyze the ultrasonic signal. The monitoring system using the pattern recognition method is composed of digital signal processing units and uses Hamming net algorithm for the recognition of ultrasonic waves. From the journal bearing wear test, the occurrence of adhesive wear of the white metal in rubbing contact with the shaft was exactly detected by this system, and the wear status of the journal bearing was monitored by measuring the wear thickness.

• 한국지능시스템학회논문지
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• 제20권1호
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• pp.94-100
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• 2010

데이터 마이닝(Data Mining)은 환경으로부터 수집된 데이터에서 패턴을 추출하고 의미 있는 정보를 발견하기 위하여 주로 사용된다. 하지만, 기존의 방법은 데이터의 수집이 완료된 상태에서 분석하는 것을 기반으로 하고 있으며, 시간의 흐름에 따른 패턴의 변화를 반영하기 어렵다. 본 논문은 연속성(Continuity data), 대량성(Large scale) 그리고 패턴의 가변성(Changed pattern)과 같은 특성을 가지는 스트림 데이터(Stream Data)의 분석을 위한 스트리밍 의사결정 나무(Streaming Decision Tree : SDT) 방법을 소개한다. SDT는 연속적으로 발생하는 데이터를 블록으로 정의하고, 각 블록은 의사결정나무 학습 방법을 이용하여 규칙을 추출한다. 추출된 규칙은 발생 시간, 빈도 그리고 모순 등을 고려하여 결합하였다. 실험에서는 시계열 데이터를 이용하여 분석하였고, 적절한 결과를 확인하였다.

• 농업과학연구
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• 제49권4호
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• pp.821-831
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• 2022

American plum line pattern virus (APLPV), a member of the genus Ilarvirus in the family Bromoviridae, is one of the plant quarantine pathogens in Korea. In this study, 15 candidate primer sets were designed and examined to develop a reverse transcription polymerase chain reaction (RT-PCR) assay for plant quarantine inspection of APLPV. Using APLPV-infected and healthy samples, the primer sets were assessed for APLPV detection. To confirm the occurrence of nonspecific reactions, six ilarviruses (Apple mosaic virus, Asparagus virus 2, Blueberry shock virus, Prune dwarf virus, Prunus necrotic ringspot virus, and Tobacco streak virus) and 10 target plants (Prunus mume, P. yedoensis, P. persica, P. armeniaca, P. dulcis, P. tomentosa, P. avium, P. glandulosa, P. salicina, and P. cerasifera) were examined. Finally, two primer sets were selected. These primer sets could generate the expected amplicons even with at least 1 ng of the total RNA template in concentration-dependent amplifications. In addition, a positive clone was developed for use as a positive control in the abovementioned RT-PCR assay.

• 한국응용곤충학회지
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• 제47권3호
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• pp.303-308
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• 2008

복숭아순나방(Grapholita molesta) 성페로몬 트랩에 미동정 나방이 포획되었다. 이들은 주로 봄에 채집되었으며 형태적으로 복숭아순나방과 유사하나 비교적 몸 크기가 커서 육안으로 쉽게 구별할 수 있다. 이들의 발생 패턴도 4-5월의 복숭아순나방 월동세대 발생과 유사하였다. 이 기간 동안 이들은 사과원 내부 보다는 주로 과수원에서 떨어진 곳에 설치된 페로몬 트랩에 집중적으로 포획되었다. 5월 이후 이들 미동정 나방은 복숭아순나방 페로몬 트랩에 더 이상 포획되지 않았다. 이 미동정 나방과 기존의 복숭아순나방과의 계통 분류학적 판별을 위해 분자마커가 개발되었다. 미토콘드리아 cytochrome b 영역을 기반으로 선발된 4종의 PCR-RFLP 분자지표는 이 미동정 나방과 복숭아순나방을 구분할 수 있었다.

• 한국지반환경공학회 논문집
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• 제17권12호
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• pp.5-16
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• 2016

This study aims to assess the influence of rainfall patterns on shallow landslides initiation. Doing so, five typical rainfall patterns with the same cumulative amount and intensity components comprising Advanced (A1 and A2), Centralized (C), and Delayed (D1 and D2) were designed based on a historical rainstorm event in Jinbu. Mt area. Those patterns were incorporated as the hydrological conditions into the Transient Rainfall Infiltration and Grid-based Regional Slope-stability Model (TRIGRS) to assess their influences on groundwater pressure and changes in the stability of the slope. The results revealed that not only the cumulative rainfall thresholds necessary to initiate landslides, but also the rate at which the factor of safety decreases and the time required to reach the critical state, are governed by rainfall patterns. The sooner the peak rainfall intensity, the smaller the cumulative rainfall threshold, and the shorter the time until landslide occurrence. Left-skewed patterns were found to have a greater effect on landslide initiation. Specifically, among five rainfalls, pattern (A1) produced the most critical state. The severity of response was followed by patterns A2, C, D1, and D2. Our conclusion is that rainfall patterns have a significant effect on the cumulative rainfall threshold, the build-up of groundwater pressure, and the occurrence of shallow landslides.

• Earthquakes and Structures
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• 제26권3호
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• pp.175-189
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• 2024

Aiming at studying the plastic hinge (PH) evolution regularities and failure mode of rocking wall moment frame (RWMF) structure in earthquakes, the whole-working history analysis of seismic performance state of RWMF structure based on co-operation performance and PH evolution was carried out. Building upon the theoretical analysis of the elastic internal forces and deformations of RWMF structures, nonlinear finite element analysis (FEA) methods were employed to perform both Pushover analysis and seismic response time history analysis under different seismic coefficients (δ). The relationships among PH occurrence ratios (R_ph), inter-story drifts and δ were established. Based on the plotted curve of the seismic performance states, evaluation limits for the R_ph and inter-story drifts were provided for different performance states of RWMF structures. The results indicate that the R_ph of RWMF structures exhibits a nonlinear evolution trend of "fast at first, then slow" with the increasing of δ. The general pattern is characterized by the initial development of beam hinges in the middle stories, followed by the development towards the top and bottom stories until the beam hinges are fully formed. Subsequently, the development of column hinges shifts from the bottom and top stories towards the middle stories of the structure, ultimately leading to the loss of seismic lateral capacity with a failure mode of partial beam yield, demonstrating a global yielding pattern. Moreover, the limits for the R_ph and inter-story drifts effectively evaluate the five different performance states of RWMF structures.

• 한국환경과학회지
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• 제26권1호
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• pp.47-54
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• 2017

We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. This study aimed to understand how C. suppressalis damages crops and to utilize this basic data for the establishment of environment-friendly control methods like pheromone traps. This study surveyed the changes in occurrence patterns of C. suppressalis, biological characteristics of overwintering larvae, and the efficacy of different types of pheromone traps the years. We found similar occurrence patterns of C. suppressalis in different crops. In addition, occurrence time of the first generation was advanced. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. It was confirmed that larvae of C. suppressalis generally prefer the lower part of the stems of Miscanthus. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. However, it is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The major Miscanthus fields are generally located in the areas protected for sources of drinking water, owing to which spraying of chemical pesticides is very limited. The results of this study provide important inputs for the development of environment-friendly control methods.

• 대한공간정보학회지
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• 제23권2호
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• pp.3-9
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• 2015

도시공간에서 토지이용변화는 교통량을 유발하고 이에 따른 교통사고발생이 상호 밀접한 관계를 갖고 있으므로 토지이용변화에 따른 교통사고발생원인 분석은 교통사고저감대책 수립에 중요한 요소로 판단된다. 이에 지방 중소도시인 진주시를 대상으로 5년간(2009년~2013년)의 교통사고 데이터를 주거지역과 상업지역의 사고 발생빈도와 최근린 분석기법에 의한 군집도를 분석한 결과 다음과 같은 결론을 얻었다. 교통사고의 발생빈도는 봄에 가장 많았고 겨울이 가장 작게 발생하였다. 또한 주간과 야간의 교통사고 발생빈도는 주간이 야간에 비해 조금 더 많이 발생하였으나 교통사고발생 군집도는 야간이 주간에 비해 강하게 나타났다. 그리고 토지용도에 따른 교통사고 군집도 분석에서 상업지역은 계절에 따른 변화가 크지 않았으나 주거지역은 겨울철에 군집밀도가 크게 낮아지는 경향을 보였다. 교통사고 유형에 따른 분석 결과 차 대 차의 측면직각추돌사고가 가장 높은 발생빈도를 보였으며 상업지역과 주거지역에 모두 광범위하게 발생되는 것으로 나타났다. 이상의 결과는 도시공간구조에서 교통사고 발생패턴을 파악하는데 중요한 정보가 될 수 있으며, 향후 교통사고저감대책을 수립하는데 유용하게 활용될 것으로 예상된다.

• 한국노년학
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• 제36권3호
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• pp.633-648
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• 2016

본 연구는 재가 노인들의 수면 양상을 확인하고 이와 관련된 우울과 인지기능의 관계에 대하여 확인하고 알아보기 위한 목적으로 실시하였다. 연구 방법은 2008년도 실시된 전국 노인 생활 실태 및 복지 요구 조사(보건복지부, 2008)의 원자료를 활용하였고, 대상자는 만 65세 이상의 남녀 12,087명이었으며 연구에 사용된 도구들은 연령, 성별, 나이, 기상 시 숙면 정도, 하루의 총 수면시간, 우울, 인지 기능의 자료를 활용하여 이차 자료분석(secondary data analysis)으로 설계하였다. 연구 결과 인구학적으로는 나이가 많은 여성들이 수면 양상이 좋지 않았으며 양적 수면의 형태인 하루의 총 수면 시간과 우울과 인지기능의 관계에서는 하루의 총 수면 시간이 6시간 이하이거나 9시간을 넘을 경우 우울 증상이 더 많았으며 질적 수면의 형태인 기상 시 숙면 정도와 우울과 인지기능의 관계에서는 숙면의 횟수가 적을수록 우울, 인지기능이 저하되었다. 이상의 결과에 근거하여 수면 양상의 변화가 노인들에게서 병적이라고 할 수는 없지만 위의 결과들을 볼 때 일차 보건 현장에서 노인들의 일상생활에서 수면의 역할을 이해하기 위해서 수면의 시간과 같은 수면의 양, 숙면 정도와 같은 수면의 질에도 초점을 두어 다각적인 접근을 통하여 노인들의 수면 양상을 확인하고 수면 장애를 관리하기 위하여 대상자 개개인에게 맞는 여러 방법의 중재 프로그램을 연구하고 개발하는 것이 필요하다고 하겠다.

• 대기
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• 제29권4호
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• pp.451-461
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• 2019

Medium-range forecast is highly dependent on ensemble forecast data. However, operational weather forecasters have not enough time to digest all of detailed features revealed in ensemble forecast data. To utilize the ensemble data effectively in medium-range forecasting, representative weather patterns in East Asia in this study are defined. The k-means clustering analysis is applied for the objectivity of weather patterns. Input data used daily Mean Sea Level Pressure (MSLP) anomaly of the ECMWF ReAnalysis-Interim (ERA-Interim) during 1981~2010 (30 years) provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). Using the Explained Variance (EV), the optimal study area is defined by 20~60°N, 100~150°E. The number of clusters defined by Explained Cluster Variance (ECV) is thirty (k = 30). 30 representative weather patterns with their frequencies are summarized. Weather pattern #1 occurred all seasons, but it was about 56% in summer (June~September). The relatively rare occurrence of weather pattern (#30) occurred mainly in winter. Additionally, we investigate the relationship between weather patterns and extreme weather events such as heat wave, cold wave, and heavy rainfall as well as snowfall. The weather patterns associated with heavy rainfall exceeding 110 mm day^-1 were #1, #4, and #9 with days (%) of more than 10%. Heavy snowfall events exceeding 24 cm day^-1 mainly occurred in weather pattern #28 (4%) and #29 (6%). High and low temperature events (> 34℃ and < -14℃) were associated with weather pattern #1~4 (14~18%) and #28~29 (27~29%), respectively. These results suggest that the classification of various weather patterns will be used as a reference for grouping all ensemble forecast data, which will be useful for the scenario-based medium-range ensemble forecast in the future.