• 대한가정학회지
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• 제44권2호
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• pp.103-112
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• 2006

This study followed the standardization study pool of K-BSID-II to examine the stability of K-BSID-II. One hundred and ninety five infants aged from 1-42 months tested twice with intervals of 5-16 month between tests. All participants had been full-term babies without any medical complications. There were no significant differences between the groups which were divided in terms of demographic variables such as mothers' education, infants' birth order and gender. The stability of K-BSID-II was significant and that of the mental scale was lower than that of the psycho-motor scale: There were high stabilities between raw scores in two sessions(r=.91 for the mental scale and r=.89 for the psycho-motor scale) but there were significant but low correlations between mental index scores(r=.18, p<.05) and psycho-motor index scores(r=.17, p<.05). The stability was increased with initial test age and mothers' education. It was recommended for testers and researchers to use both raw scores and index scores for better interpretations in future research.

• 제어로봇시스템학회논문지
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• 제16권7호
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• pp.646-654
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• 2010

This paper describes an integrated chassis control for a maneuverability, a lateral stability and a rollover prevention of a vehicle by the using of the ESC and AFS. The integrated chassis control system consists of a supervisor, control algorithms and a coordinator. From the measured and estimation signals, the supervisor determines the vehicle driving situation about the lateral stability and rollover prevention. The control algorithms determine a desired yaw moment for lateral stability and a desired longitudinal force for the rollover prevention. In order to apply the control inputs, the coordinator determines a brake and active front steering inputs optimally based on the current status of the subject vehicle. To improve the reliability and to reduce the operating load of the proposed control algorithms, a multi-core ECU platform is used in this system. For the evaluation of this system, a closed loop simulations with driver-vehicle-controller system were conducted to investigate the performance of the proposed control strategy.

• 한국항해학회지
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• 제7권1호
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• pp.63-81
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• 1983

A vessel encountered heavy weather is face to two kinds of danger ; the danger of upset due to the lack of stability and the lack of the longitudinal strength. Generally a small vessel is face to the former and the large vessel to the latter. Most of people do not consider the danger of upset by the latter but the former. But many ships missed at sea, the exact causes being not known. This pper investigated and analyzed the causes of accidents. The result was that the lohgitudinal strength of the hull is not enough to cope with heavy weather, and the particular cautions are needed to handle a ship in heavy weather.

• International Journal of Automotive Technology
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• 제8권3호
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• pp.351-359
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• 2007

In this study, a hierarchical switching control scheme based on robust control theory is proposed for tracking control of vehicle longitudinal acceleration in the presence of large uncertainties. A model set consisting of four multiplicative-uncertainty models is set up, and its corresponding controller set is designed by the LMI approach, which can ensures the robust performance of the closed loop system under arbitray switching. Based on the model set and the controller set, a switching index function by estimating the system gain of the uncertainties between the plant and the nominal model is designed to determine when and which controller should be switched into the closed loop. After theoretical analyses, experiments have also been carried out to validate the proposed control algorithm. The results show that the control system has good performance of robust stability and tracking ability in the presence of large uncertainties. The response time is smaller than 1.5s and the max tracking error is about $0.05\;m/S^2$ with the step input.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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• pp.80-85
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• 1992

A nonlinear second-order analysis program that properly describes the nonlinear behavior of concrete was developed by using the layering technique. As the slenderness ratio of column is increased, the peaks of P-M curve lie remote from the section interaction diagram for the same eccentricities. But the peaks of P-M curve lie rather close to the section interaction diagram for very large eccentricities. In this study , the effects of compressive strength of concrete, longitudinal steel ratio, and yield strength of steel on second-order moment of concrete columns were analyzed. As the compressive strength of concrete and the yield strength of steel are increased, the ratio of peak axial force to maximum axial strength for concentrically loaded short column( Pu/Po) is decreased. But as the longitudinal steel ratio is increased, the ratio , Pu/Po increases.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권1호
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• pp.31-37
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• 2001

A robust adaptive technique for the longitudinal control of a platoon of automated vehicles is presented. A nonlinear model is used to represent the dynamics of each vehicle within the platoon. The external disturbances such as wind gust and a disturbance term due to engine transmission variations and so on are considered. The state observer is used to avoid direct measurement of the relative velocity or acceleration between the controlled and leading vehicles or the controlled vehicles's acceleration. The proposed controller guarantees to recover platoon stability in operation even if a speed dependent spacing policy is adopted, which incorporates a constant time headway in addition to the constant distance. It is shown that the proposed observer is exponentially stable, and the at the robust adaptive controller is stable. The simulation results demonstrate excellent tracking even in the presence of disturbances.

• 아동학회지
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• 제36권5호
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• pp.75-94
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• 2015

This study examined short-term longitudinal reciprocal relationships between maternal parenting behavior and preschoolers' compliance/noncompliance, as well as stability in both maternal parenting behavior and preschoolers' compliance/noncompliance over time. The sample which was used for this study was taken from a two-wave (one year apart) longitudinal study of preschool-aged children and their mothers (N = 53 dyads). At both times, mothers and their children were invited to a laboratory and engaged in 25 minutes of play involving three episodes of mother-child interaction. Maternal parenting behavior and preschoolers' compliance/noncompliance during play were coded using the Dyadic Parent-Child Interaction Coding System-III (DPICS-III). Maternal codes included positive, neutral, and negative parenting behaviors and child codes were comprised of compliance and noncompliance. The results revealed that during the play session, maternal neutral and negative parenting behavior and preschoolers' compliance were stable over time. In addition, T1 maternal negative parenting behavior was significantly related to T2 child compliance/noncompliance. However, T1 child compliance/noncompliance were not significantly associated with T2 maternal parenting behavior. These findings suggest that during the preschool period, there are unidirectional effects from mothers to children.

• 한국터널지하공간학회 논문집
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• 제13권6호
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• pp.501-517
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• 2011

일반적으로 터널 시공현장에서는 계측된 천단 및 내공변위와 계측관리기준을 비교하여 터널의 안정성을 판단한다. 현재 계측관리기준은 지반조건, 터널단면의 크기, 시공방법, 지보재량 등을 고려한 경험을 통해 세워지고 있는 실정이다. 따라서 새로운 계측관리기준으로 한계변형률을 이용하는 방법에 대한 연구가 다수 수행되었다. 그러나 대부분의 연구는 일축압축강도실험에서 얻어진 한계변형률을 기준으로 삼고 있어 실제 터널 굴착 시 발생하는 응력의 증가 및 종방향 아칭에 의한 암반 손상을 고려하지 않는 문제점을 가지고 있다. 따라서 본 연구에서는 국내 대표 암종인 화강암과 편마암의 한계변형률 특성을 조사하기 위하여 일축압축강도실험과 응력의 증가 및 종방향 아칭을 고려한 손상제어실험을 수행하였다. 손상제어실험에서 얻어진 한계변형률은 일축압축강도실험에서 얻어진 한계변형률보다 다소 작게 나타났다. 이는 일축압축강도실험에서 얻은 한계변형률은 터널 굴착 시의 응력이력을 고려하여 다소 감소시켜야 한다는 것을 의미한다. 또한 대심도 터널에서 흔히 발생하는 취성파괴를 평가하기 위한 손상한계변형률을 제안하였다.

• 한국산림과학회지
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• 제89권3호
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• pp.397-404
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• 2000

임도 옆도랑침식에 영향을 미치는 요인의 평가 및 안정도 판별을 위하여 광릉시험림의 임도를 대상으로 조사를 실시한 결과 침식에 미치는 기여순위는 종단물매, 시설위치, 절토사면경사, 절토사면구성물질, 유하거리, 노면형태, 노면재료, 절토사면피복도, 절토사면길이 순으로 나타났다. 임도 옆도랑침식을 유발하는 요인을 평가하면, 종단물매는 8% 이상, 임도시설위치는 산록(山麓)과 중복(中腹), 절토사면경사는 $50^{\circ}$ 이상, 절토사면토성은 견질토사, 자갈섞인 토사, 호박돌섞인 토사, 유하거리는 80m 이상의 지역에서, 그리고 노면재료는 토사도(土砂道)와 자갈부설도에서, 노면형태의 경우에는 철(凸)형과 직선형, 절토사면 피복도(被覆度)는 피복도가 중(中)이상인 곳에서 임도 옆도랑침식이 발생할 가능성이 높은 것으로 예측(豫測)되었다.

• 한국지반공학회논문집
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• 제20권9호
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• pp.133-144
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• 2004

NATM터널 시공 중 강관이나 FRP관을 이용하여 터널 막장을 선행보강하는 방법은 RPUM이나 UAM 등으로 알려져 있으며, 얕은 터널 및 연약지반내 터널 굴착 시 굴진면의 안정성을 확보해주거나 지반 침하를 감소시켜주는 역할을 한다. 특히 굴진지반이 연약하여 자립이 어려운 경우 최근에는 굴진면 천단뿐 아니라 굴진면 수평보강을 실시하여 굴착에 따른 터널안정을 확보하게 된다. 일반적으로 터널굴착이 진행됨에 따라 굴진면 전후에는 종방향 아칭현상이 발생하며 이는 NATM 터널 지보재 작용원리의 근간이 된다. 따라서 터널 천단과 굴진면 수평보강을 실시하는 경우도 굴진에 따른 종방향 아칭의 관점에서 해석되어야 하나 이에 대한 연구는 현재까지 거의 없는 실정이다. 본 연구에서는 토사터널 굴진면에 RPUM(천단보강)이나 굴진면 수평보강이 실시된 경우, 종방향 아칭특성을 2차원 실내시험을 통해 살펴보았다. 실험결과, 연직토압의 변화를 토대로 한 종방향아칭 영향범위는 무보강의 경우 굴진면 전${\cdot}$후방으로 각각 2.5D와 1.5D(D는 터널직경), 천단보강 및 수평보강의 경우 2.0D와 1.5D, 천단과 수평보강이 동시에 적용된 경우는 2.0D와 1.0D까지로 측정되어 굴진면 보강에 따라 아칭의 영향범위가 감소함을 알 수 있었다. 반면 연직토압의 변화량은 굴진면 보강에 따라 증가하는 것으로 나타나 역학적으로 천단 및 수평보강재가 터널의 안정에 중요한 역할을 하고 있는 것으로 판단된다.