• 한국멀티미디어학회논문지
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• 제12권2호
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• pp.165-177
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• 2009

센서노드(sensor node)에서의 데이터 기록을 위해 NAND 플래시 메모리 기반의 임베디드 데이터베이스 시스템이 널리 사용되고 이다. 플래시 메모리의 쓰기 및 삭제연산은 읽기 연산에 비해 시간이 많이 소모되고 기억 소자를 마모시킨다. 따라서 이러한 연산들을 줄이는 것은 데이터베이스 시스템의 성능 향상과 메모리의 수명 증대 측면에서 중요하다. 본 논문에서는 이를 위해 지연쓰기 기법을 제안한다. 이 기법은 데이터페이스 페이지의 갱신 영역을 별도의 지연쓰기 레코드로 저장하여 데이터베이스 페이지 쓰기를 줄임으로써 플래시 메모리에 대한 쓰기연산과 삭제 연산을 감소시킨다. 따라서 제안하는 기법은 데이터 기록의 비중이 높은 센서노드 데이터베이스 시스템의 성능을 높이고 플래시 메모리의 수명을 늘리게 된다.

• 한국통신학회논문지
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• 제37권7A호
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• pp.503-511
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• 2012

이 논문은 지연프레임 시간다이버시티(DFTD)를 외부코드로 사용하고 RS 코드를 내부코드로 사용하는 원격측정방식의 성능분석에 대하여 기술한다. DFTD는 탑재장치에서 실시간 프레임과 더불어 임의 시간동안 지연된 프레임을 함께 전송하고 지상에서 각 프레임을 병합하는 방식이다. RS 코드는 DFTD에 직렬로 연결되어지는 FEC(forward error correction) 코드이다. 이 방식을 원격측정장치 설계에 적용하여 깊은 페이딩이 존재하는 통신환경에서 비행시험을 수행하였다. 비행시험 결과를 사용하여 코드적용이 없을 경우, DFTD만 적용할 경우, RS 코드만 적용할 경우와 DFTD와 RS 코드를 함께 적용할 경우에 대하여 각각의 성능을 분석한다. 시간지연 모의는 모든 프레임오류 제거 가능성을 보여주고 12회 비행시험 결과는 새로운 원격측정방식의 성능 우수성을 RS코드만 적용하였을 경우와 비교하여 보여준다.

• 전자공학회논문지CI
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• 제41권4호
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• pp.1-8
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• 2004

PCI 2.2 버스 마스터가 메모리 읽기 명령으로 타겟 장치에 데이터 전송을 요구하면 타겟 장치는 내부적으로 데이터 준비하는데 시간이 필요하므로 데이터 전송 없이 장시간 PCI 버스를 점유하는 상황이 발생할 수 있다. 이는 PCI 버스 사용 효율 및 데이터 전송 효율을 떨어뜨리게 되며 이를 해결하기 위해 PCI 2.2에서는 지연 트랜잭션 메커니즘을 이용한다. 그러나 이 방법은 타겟 장치가 프리페치해야 할 정확한 데이터의 양을 알 수 없기 때문에 데이터 전송 효율이 떨어진다. 본 논문에서는 메모리 읽기 명령을 수행하고자 하는 버스 마스터가 메모리 쓰기 명령어를 이용하여 타겟 장치에게 읽어올 데이터의 양을 미리 알려주는 프리페치 요구를 이용해 보다 효율적으로 데이터를 전송하는 방법을 제안한다. 모의실험 결과 제안된 방법이 지연 트랜잭션에 비해 데이터 전송 효율이 평균 10 % 향상되었다.

• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.145-152
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• 2021

Environmental change due to construction of large offshore wind farm has been a debate for a long time in Korea. There are various data acquired on hydrodynamics around this area before and during construction of offshore wind farm but no data during operation could be made due to delayed schedule. In this study, environmental change such as bathymetry change and scouring was forecasted using MIKE, numerical hydrodynamics model, and its results were validated using the observation data before and during construction.

• 대한간호학회지
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• 제27권2호
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• pp.389-400
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• 1997

This study examined the effects of group social support on the reduction of burden and increase in well-being of mothers of developmentally delayed children. The research used a one group pre-pose experimental design. The independent variable in the experiment was group social support. Two series of 4-weekly meetings for group social support were conducted by the researcher with the intention of developing a self-help group. The dependent variables were burden and well-being. Well-being was operationalized as physical symptoms and quality of life. Thirty mothers of developmentally delayed infants from the rehabilitation center of a medical center participated in the study. Data were collected by interviews and a self-administered questionnaire. The mean age of the subjects was 29.9 years. Changes of the dependent variables between pre and post tests were compared using the t-test. Even though there was a slight improvement in the scores for the dependent variables, they were not statistically significant. The items, "I resent my baby". "I feel angry about my interactions with my baby", "I feel guilty in my relationship with my baby" showed a significant decrease in burden score and were statistically significant. Symptoms of loneliness, constipation, anxiety, restlessness were less and feeling of happiness was greater after participation in the group social support, than on the pretest. The mothers showed emotional instability and frustrations during the group sessions but their reactions in general were positive. Emotional support, stress management and information provided were identified as the most valuable content of the sessions. However, participation was not active due to the mother's denial, delayed acceptance and /or avoidance of their infants' problems. It can be seen that group social support for the mothers with developmentally delayed children should be provided after infancy when the mothers have time to accept their children's conditions and are ready to receive support. The use of comprehensive instruments which measure burden in both families and mothers needs to be developed for future research.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.548-553
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• 1992

In this paper and recursive version of orthogonal ARMA identification algorithm is proposed. The basic algorithm is based on Gram-Schmidt orthogonalization of automatically selected basis functions from specified function space, but does not require explicit creation of orthogonal functions. By using two dimensional autocorrelations and crosscorrelations of input and output with constant data length, identification algorithm is extended to cope slowly time-varying or order-varying delayed system.

• 전자공학회논문지B
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• 제31B권4호
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• pp.48-54
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• 1994

A recursive on-line algorithm with orthogonal ARMA identification is proposed for linear systems with unkonwn time delay, order, and parameters. The algorithm is based on the Gram-Schmidt orthogonalization of basis functions, and extendedto recursive form by using two dimensional autocorrelations and crosscorrelations of input and output with constant data length. The proposed algorith can cope with slowly time-varying or order-varying delayed system. Various simulations reveal the performance of the algorithm.

• 한국전문물리치료학회지
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• 제6권1호
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• pp.47-61
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• 1999

The purpose of this study was to investigate factors influencing on the early treatment of children with developmental disability. Data was collected from 102 mothers of children with developmental disability who were treated at 4 rehabilitation facilities in Kyunggi-Do and Kangwon-Do. The results were as follows: 1) Of a total of 102, 63 children began to receive rehabilitation therapy during the period 0~12 months (early treatment group), 38 children after 1 year of age (delayed early treatment group). 2) There were statistically significant differences between the early treatment group and delayed early treatment group for prematurity, low birth weight, the time to discover developmental abnormalities, the time of first diagnosis, and first treatment (p<0.05). 3) There were no statistically significant differences in the two groups for level of education, economic status, risk factors (except prematurity and birth weight), home care, family's cooperation and commuting time (p>0.05). Based on this study, the important factors for early treatment were early detection, early diagnosis and constant follow-up for high-risk babies.

• 말소리와 음성과학
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• 제9권4호
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• pp.115-122
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• 2017

This study attempts to determine the extent to which late talkers are at the risk of delayed phonological development, in order to identify groups at risk and to find factors affecting delayed phonological development. A group of 1,452 children (51% boys, 49% girls) were recruited from the nationwide Panel Study on Korean Children. The current study collected data from 418 children who were previously identified as late-talkers (LT) at their age of three on average (Time 1: expressive vocabulary test) and three years later (Time 2: phonological test). Their phonological outcomes of the Time 2 were analyzed and then compared to those of a group of 1,056 children with typical language development (NLT: no late-talkers) at the age of three in terms of the number of incorrect consonants, and the speech sound disorders rating scores. LT showed a lower articulation score than NLT, and boys showed a lower score than girls. These findings indicate that the late onset of speech and the gender of young children could be potential risk factors of speech sound disorders.

• 한국안전학회지
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• 제33권3호
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• pp.83-91
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• 2018

This paper suggests a weibull time delay model to evaluate failure risks in FMEA(failure modes and effects analysis). Assuming three types of loss functions for delayed time in failure cause detection, the risk of each failure cause is evaluated as its occurring frequency and expected loss. Since the closed form solution of the risk metric cannot be obtained, a statistical computer software R program is used for numerical calculation. When the occurrence and detection times have a common shape parameter, though, some simple results of mathematical derivation are also available. As an enormous quantity of field data becomes available under recent progress of data acquisition system, the proposed risk metric will provide a more practical and reasonable tool for evaluating the risks of failure causes in FMEA.