• International Journal of Aeronautical and Space Sciences
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• 제13권3호
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• pp.369-376
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• 2012

A nonlinear robust guidance law is designed for missiles against a maneuvering target by incorporating sliding-mode and optimal control theories based on the state dependent Riccati equation (SDRE) to achieve robustness against target accelerations. The guidance law is derived based on three-dimensional nonlinear engagement kinematics and its robustness against disturbances is proved by the second method of Lyapunov. A new switching surface is considered in the sliding-mode control design. The proposed guidance law requires the maximum value of the target maneuver, and therefore opposed to the conventional augmented proportional navigation guidance (APNG) law, complete information about the target maneuver is not necessary, and hence it is simple to implement in practical applications. Considering different types of target maneuvers, several scenario simulations are performed. Simulation results confirm that the proposed guidance law has much better robustness, faster convergence, and smaller final time and control effort in comparison to the sliding-mode guidance (SMG) and APNG laws.

• Journal of Power Electronics
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• 제18권5호
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• pp.1380-1397
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• 2018

The synchronous reluctance motor (SynRM) servo-drive system has highly nonlinear uncertainties owing to a convex construction effect. It is difficult for the linear control method to achieve good performance for the SynRM drive system. The nonlinear backstepping control system using upper bound with switching function is proposed to inhibit uncertainty action for controlling the SynRM drive system. However, this method uses a large upper bound with a switching function, which results in a large chattering. In order to reduce this chattering, a nonlinear backstepping control system using an adaptive law is proposed to estimate the lumped uncertainty. Since this method uses an adaptive law, it cannot achiever satisfactory performance. Therefore, a nonlinear backstepping control system using a reformed recurrent Hermite polynomial neural network with an adaptive law and an error estimated law is proposed to estimate the lumped uncertainty and to compensate the estimated error in order to enhance the robustness of the SynRM drive system. Further, the reformed recurrent Hermite polynomial neural network with two learning rates is derived according to an increment type Lyapunov function to speed-up the parameter convergence. Finally, some experimental results and a comparative analysis are presented to verify that the proposed control system has better control performance for controlling SynRM drive systems.

• Journal of Sport and Applied Science
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• 제3권1호
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• pp.19-25
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• 2019

Purpose: Children's swimming pools are picking up faster than the other types of swimming pool. Yet, safety law-related studies are still lack. This study is to review legal status of children's swimming pool in Korea and to discuss the related legal issues for safety management of children's swimming pool. Research design, data, and methodology: The study reviewed law and clauses for sport facility management and related legal clauses with chilren's swimming pool management, and sport facility-related articles. Results: Safety management of children's swimming pool should currently follow law for sport and physical education facility management because of no its own legal norm for children's swimming pool. Given this, specific law and clauses for children's pool management need to be legislated to prevent risks for children and to satisfy specific safety factors considering careless behavior of children. Conclusions: Regarding this, the study points out five suggestions. First, law should be established to make notification of safety rules mandatory and this notification should be placed in the pool. This notification would be better effective if it is visualized. Second, according to law, safety 7 rules of children' s swimming pool need to be legistrated and educated for pool managers to obey them. Pool managers could also add their own rules to the 7 rules. Finally, preparation of emergency kits and safety devices need to be mandatory in the pool. Further implications were discussed.

• 융합보안논문지
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• 제16권2호
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• pp.55-62
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• 2016

최근 국내 국가연구개발사업(R&D)을 진행하는 과정에서 연구성과물 유출사고가 빈번하게 발생하고 있다. 이러한 유출사고를 대비하기 위해 연구보안 관련법과 매뉴얼 등의 보안체계를 마련하여 시행하고 있지만, 단순한 기술적 조치의 단편적 방법으로는 한계점이 존재하고 있다. 따라서 본 연구에서는 연구개발 생애주기 관점에 근거하여, 보안조치 방법을 다차원적으로 설계함으로서 통합적인 연구보안 관리체계를 구축하고자 한다. 세부적으로 관련법령에 근거하여 다양한 통제영역들을 구성하고, 연구보안 평가항목의 적용가능성을 검토하고자 한다.

• 한국산업융합학회 논문집
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• 제10권3호
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• pp.149-155
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• 2007

Damage assessment and Damage index for RC members failed in flexure was investigated by using the nonlinear finite element analysis, included with nonlocal constitutive law, which is analyzed for the localization of the failure on the post-peak region. In the nonlcal constitutive law, The local strains obtained at gauss points were averaged over a particular length, i.e. characteristic length and it was used to evaluate the damage of RC column member. As the analysis results, The value of nonlocal strain shows less mesh sensibility. In the damage assessment, It was confirmed that evaluations of damage of RC member were able to use nonlocal compressive strain on a cover concrete and a core concrete of the member. Moreover it was confirmed that damage process for the statically indeterminate structure was able to evaluate the damage context of the component members of the structure.

• 대한수학회보
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• 제59권4호
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• pp.879-895
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• 2022

This paper establishes the Baum-Katz type theorem and the Marcinkiewicz-Zymund type strong law of large numbers for sequences of coordinatewise negatively associated and identically distributed random vectors {X, X_n, n ≥ 1} taking values in a Hilbert space H with general normalizing constants $b_n=n^{\alpha}{\tilde{L}}(n^{\alpha})$, where ${\tilde{L}}({\cdot})$ is the de Bruijn conjugate of a slowly varying function L(·). The main result extends and unifies many results in the literature. The sharpness of the result is illustrated by two examples.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2024년도 제69차 동계학술대회논문집 32권1호
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• pp.403-406
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• 2024

본 논문에서는 비눗방울에 나타나는 반사와 굴절 효과를 상용 게임엔진인 유니티 쉐이더(Unity shader)를 사용하여 구현하고 다양한 배경에서 합성할 수 있는 효율적인 프레임워크를 제안한다. 본 논문에서 제안하는 방법은 계산량이 큰 유체 시뮬레이션을 이용하지 않고, 스넬(Snell)의 법칙을 이용하여 박막 내부의 굴절 벡터를 계산하고, 막 표면의 표현을 위해 다양한 텍스처(Texture)를 적용하였으며, vertex의 조정을 통해 비눗방울 자체의 움직임을 나타낼 수 있다. 결과적으로 실시간으로 높은 품질의 비눗방울을 표현할 수 있기 때문에 게임뿐만 아니라 가상현실 및 다양한 실시간 애플리케이션에 활용될 수 있다.

• 대한수학회지
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• 제42권5호
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• pp.949-957
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• 2005

For weighted sum of a sequence {X, X$\_{n}$, n $\geq$ 1} of identically distributed, negatively orthant dependent random variables such that |r| > 0, has a finite moment generating function, a strong law of large numbers is established.

• Journal of the Korean Data and Information Science Society
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• 제4권
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• pp.53-63
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• 1993

We consider various types of weak convergence for sums of sign-invariant random variables. Some results show a similarity between independence and sign-invariance. As a special case, we obtain a result which strengthens a weak law proved by Rosalsky and Teicher [6] in that some assumptions are deleted.

• Journal of the Korean Statistical Society
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• 제33권1호
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• pp.99-106
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• 2004

Let {X, $X_{n}, n\;{\geq}\;1$} be a sequence of identically distributed, negatively associated (NA) random variables and assume that $│X│^{r}$, r > 0, has a finite moment generating function. A strong law of large numbers is established for weighted sums of these variables.