• 대한가정학회지
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• 제48권5호
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• pp.25-48
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• 2010

The purpose of this study was to employ the Latent Growth Curve Model(LGM) to investigate the developmental trajectories of children's internalizing and externalizing problem behaviors and to identify predictors that might have an effect on change and the level of developmental trajectories. Furthermore, we classified the developmental trajectories of children's internalizing and externalizing problem behaviors, and also analyzed factors which caused differences in developmental trajectories by Semi-Parametric Group-based Modeling. This study used data from wave 1-4(2004~2008) of elementary school fourth grade panel of the Korea Youth Panel Survey(KYPS). The results showed that children's internalizing and externalizing problem behaviors changed significantly from the fourth grade of elementary school to the first grade of middle school. The predictors for developmental trajectories of children's internalizing problem behaviors were gender, self-control, parental conflict, deviant peers, and attachment to teachers. The predictors for the developmental trajectories of children's externalizing problem behaviors were gender, self-esteem, self-control, and deviant peers. The developmental trajectories of children's internalizing problem behaviors was classified into three groups. The developmental trajectories of children's externalizing problem behaviors was classified into four groups.

• 한국공간정보시스템학회 논문지
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• 제9권3호
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• pp.51-65
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• 2007

도로 네트워크 상의 이동 객체 궤적을 분석하기 위해서는 그것의 표현이 명확하게 정의되어야 한다. 도로 네트워크 상의 이동 객체 궤적을 표현하는 기존의 대부분의 방법들은 이동 객체 궤적을 그 궤적이 통과한 위치와 시간의 집합으로 복잡하게 표현한다. 이것은 이동 객체 궤적의 검색 등과 같은 분석을 처리할 시 많은 시간이 요구된다. 본 논문에서는 도로 네트워크 상의 관심 있는 지점(POI: Points of Interest)들에 초점을 두어 도로 네트워크 상의 이동 객체 궤적을 효율적으로 간략화 하는 방법을 제시한다. 본 논문에서 제시하는 방법은 도로 네트워크 상의 이동 객체 궤적이 통과한 POI의 수를 줄임으로써 궤적을 간략화 하며, 궤적이 간략화 된 후에도 그 궤적의 형태를 그대로 유지하도록 한다.

• 대한가정학회지
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• 제48권10호
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• pp.89-103
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• 2010

The purpose of this study was to examine the developmental trajectories of adolescents' internalizing problem behaviors. The data came from 3,188 middle school students through their participation in the Korea Youth Panel Survey(KYPS). Adolescents with a high level of internalizing problem behaviors in the first year showed a rapid decline in these behaviors over time, whereas for adolescents with a low level of these behaviors in the first year the decline was slow. The predictors of the developmental trajectories were related to individual variables, such as gender, self-esteem, self-control, stress, self-stigmatization, and academic achievement. The developmental trajectories of adolescents' internalizing problem behaviors were classified into four groups. The predictors of the patterns of developmental trajectories in adolescents' internalizing problem behaviors appeared to be related to individual variables.

• International Journal of Aeronautical and Space Sciences
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• 제3권1호
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• pp.39-49
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• 2002

This paper presents a robust tracker design method that is specific to the trajectories of target aircraft. This method assumes that representative trajectories of the target aircraft are available. The exact trajectories known to the tracker enables the incorporation of the exact data in the tracker design instead of the measurement data. An estimator is designed to have acceptable performance in tracking a finite number of different target trajectories with a capability to trade off the mean and maximum errors between the exact trajectories and the estimated or predicted trajectories. Constant estimator gains that minimize the cost functions related to the estimation or prediction error are computed off-line from an iterative algorithm. This tracker design method is applied to the longitudinal motion tracking of target aircraft.

• 아동학회지
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• 제36권4호
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• pp.209-227
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• 2015

The present study investigated maternal parenting stress trajectories, using data gathered from the Korean Children Panel Survey. Four factors-monthly income, maternal depression levels, infants' negative emotionality, marital conflict-which were taken from reports made by the mothers' used in this study, were examined as predictors of maternal parenting stress trajectories. The effects of maternal parenting stress trajectories, parenting styles and toddlers' peer interruptive behaviors were also examined. The findings were as follows: First, maternal parenting stress trajectories somewhat increased from the 1st year period to the 4th year period. Second, infants' negative emotionality and marital conflict within the first year were observed to have a connection to the initial level and slope of maternal parenting stress trajectories. Third, maternal parenting stress trajectories predicted positive parenting styles, and parenting styles had a longitudinal impact on toddlers' peer interruptive behaviors at the 5th year period.

• 정보처리학회논문지D
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• 제13D권3호
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• pp.337-346
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• 2006

이동 객체들의 행동을 분석하기 위해서는 그 이동 객체 궤적들 간의 유사성 측정을 정의하는 것이 필요하다. 비록 유클리디언 공간 상에서 이동 객체들의 유사한 궤적들을 검색하는 몇몇 연구가 있었지만, 도로 네트워크 공간 상에서 이동 객체들의 궤적에 대한 유사성 연구는 거의 관심을 끌지 못 했다. 실제 응용에서, 대부분의 이동 객체들은 유클리디언 공간보다 도로 네트워크 공간 상에 존재한다. 그러나 궤적들 간의 유사성 측정에서, 기존의 방법들은 유클리디언 거리를 기반으로 하고 있으며, 오직 공간적 유사성만을 고려하고 있다. 본 논문에서, 우리는 도로네트워크 상에서 POI와 TOI를 기반으로 유사성 측정을 정의한다. 이러한 정의를 바탕으로, 우리는 궤적들 간의 시공간 유사성을 사용하여 유사한 궤적을 검색하는 방법들을 제시한다. 그리고 유사한 궤적들에 대하여 클러스터링을 수행한 결과를 보인다. 실험 결과는 각 방법에 의해 검색된 유사한 궤적들과 그 검색된 궤적 결과들이 각 방법 간에 얼마나 일치하는지를 보인다.

• 아동학회지
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• 제30권3호
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• pp.113-125
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• 2009

This study advances knowledge of developmental patterns in poverty and delinquency; data was obtained from waves 1-5 (2003-2007) of the Korea Youth Panel Survey. Semi-parametric group-based modeling (SGM) identified 4 trajectories of poverty from age 13 to 17 : non-poor, poverty increasing, low-level continuous poverty and chronic poverty groups and five developmental trajectories of delinquency : non-offending, late onset, low-level continuous, desisting, and chronic groups. A joint trajectory method predicted patterns of delinquency conditional on poverty trajectories. Chronic and low-level continuous poverty groups were more likely than others to follow chronic trajectories of delinquency; the non-poor group was more likely to be non-offending. Implications of this study for youth welfare were discussed to reduce risk for delinquency.

• 말소리와 음성과학
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• 제4권1호
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• pp.21-28
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• 2012

Many previous studies reported acoustic parameters of English vowels produced by a clear speaking style. In everyday usage, we actually produce speech sounds with various speaking styles. Different styles may yield different acoustic measurements. This study attempts to examine pitch and formant trajectories of eleven English vowels produced by nine American males in order to understand acoustic variations depending on clear and conversational speaking styles. The author used Praat to obtain trajectories systematically at seven equidistant time points over the vowel segment while checking measurement validity. Results showed that pitch trajectories indicated distinct patterns depending on four speaking styles. Generally, higher pitch values were observed in the higher vowels and the pitch was higher in the clear speaking styles than that in the conversational styles. The same trend was observed in the three formant trajectories of front vowels and the first formant trajectories of back vowels. The second and third trajectories of back vowels revealed an opposite or inconsistent trend, which might be attributable to the coarticulation of the following consonant or lip rounding gestures. The author made a tentative conclusion that people tend to produce vowels to enhance pitch and formant differences to transmit their information clearly. Further perceptual studies on synthesized vowels with varying pitch and formant values are desirable to address the conclusion.

• 말소리와 음성과학
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• 제11권1호
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• pp.1-8
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• 2019

Formant trajectories reflect the continuous variation of speakers' articulatory movements over time. This study examined formant trajectories of English vowels produced by ninety-three American men and women; the values were normalized using the scale function in R and compared using generalized additive mixed models (GAMMs). Praat was used to read the sound data of Hillenbrand et al. (1995). A formant analysis script was prepared, and six formant values at the corresponding time points within each vowel segment were collected. The results indicate that women yielded proportionately higher formant values than men. The standard deviations of each group showed similar patterns at the first formant (F1) and the second formant (F2) axes and at the measurement points. R was used to scale the first two formant data sets of men and women separately. GAMMs of all the scaled formant data produced various patterns of deviation along the measurement points. Generally, more group difference exists in F1 than in F2. Also, women's trajectories appear more dynamic along the vertical and horizontal axes than those of men. The trajectories are related acoustically to F1 and F2 and anatomically to jaw opening and tongue position. We conclude that scaling and nonlinear testing are useful tools for pinpointing differences between speaker group's formant trajectories. This research could be useful as a foundation for future studies comparing curvilinear data sets.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.254-259
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• 1992

In this paper, we propose an optimal method for the tracking a trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint equations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation of flexible planner manipulator is presented.