• Journal of Advanced Marine Engineering and Technology
• /
• v.21 no.2
• /
• pp.101-107
• /
• 1997

고전제어와 현대제어의 이론을 선형제어론을 중심으로 각각의 특징을 간략히 살펴보았다. 21세기의 문턱에 서 있는 현재, 과학의 발전은 급진전하고 있음은 주지하는 바이며, 이러한 시점에서 천학비재한 필자가 제어계의 미래를 전망한다는 것은 대단히 어려운 일이지만, 현재 상황으로 볼 때 짧은 기간의 미래에는 강인성에 중점을 둔 제어기의 설계에 관한 연구가 계속 되어지리라고 본다. 그리고 컴퓨터 기술의 발달과 더불어 복잡한 제어 알고리즘도 쉽게 실현될 수 있으므로 뉴럴네트워크 및 인공지능에 의한 제어 기술도 크게 발전될것으로 생각된다. 한편 일반적인 제어기의 설계 순서는 대상으로 하는 플란트의 동특성을 고려하여 플란트를 수학적으로 모델링하고, 모델링된 공칭모델을 기초로 하여 제어기를 설계한 다음, 시뮬레이션 및 실험을 통하여 설계된 제어계의 타당성을 검토하여 불만족스러운 경우는 제어계를 재설계하거나, 나아가 모델링을 다시 하는 것이 통상적으로 이용되어온 설계 순서였다. 이 경우는 플란트의 모델링 과정과 제어기 설계 과정이 완전히 독립적으로 이루어졌다. 그러나 최근 모델링과 제어기 설계의 불가분(나눌수 없음) 성이 제기되면서, 시스템의 동정(identification)과 보상기(compensator)의 통합화 설계기법이 제안되고 있으며, 앞으로 이 연구 테마도 흥미있는 한 분야가 될 것으로 생각된다.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.404-405
• /
• 2011

원전구조물의 방사성 폐기물 처분시설의 경우 지하수에 해수가 유입되어 콘크리트에 염소이온 침투가 발생할 수 있으며, 콘크리트 내부에 존재하는 인장철근의 부식에 의한 내구성 저하 및 수명 단축이 주된 문제가 된다. 본 논문에서는 원전콘크리트 구조물에서의 확산에 의한 염소이온 침투에 대한 수학적 모델을 제시하였다. 콘크리트 중의 염소이온의 침투는 콘크리트의 노출환경, 습윤상태에 따라 확산(Diffusion), 대류(Absorption), 전기적 이동(Migration)에 의해 발생한다. 이러한 조건을 모두 고려하여 제시한 방정식에 의해 염소이온의 침투를 예측할 수 있다.

• Journal of Advanced Navigation Technology
• /
• v.17 no.3
• /
• pp.292-297
• /
• 2013

In this paper, The design of digital circuits for chaotic composition function which is used for the key-stream generator is studied in this work. The overall design concept and procedure due to the mathematical model of chaotic key-stream generator is to be the explained in detail, and also the discretized truth table of chaotic composition function is presented in this paper. consequently, a composition state machine based on the compositive map with connecting two types of one dimensional and two dimensional chaotic maps together is designed and presented.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2021.06a
• /
• pp.271-274
• /
• 2021

Fisheye 카메라로 촬영된 영상은 일반 영상보다 넓은 시야각을 갖는 장점으로 여러 분야에서 활용되고 있다. 그러나 fisheye 카메라로 촬영된 영상은 어안렌즈의 곡률로 인하여 영상의 중앙 부분은 팽창되고 외곽 부분은 축소되는 방사 왜곡이 발생하기 때문에 영상을 활용함에 있어서 어려움이 있다. 이러한 방사 왜곡을 보정하기 위하여 기존 영상처리 분야에서는 렌즈의 곡률을 수학적으로 계산하여 보정하기도 하지만 이는 각각의 렌즈마다 왜곡 파라미터를 추정해야 하기 때문에, 개별적인 GT (Ground Truth) 영상이 필요하다는 제한 사항이 있다. 이에 본 논문에서는 렌즈의 종류마다 GT 영상을 필요로 하는 기존 기술의 제한 사항을 극복하기 위하여, fisheye 영상만을 입력으로 하여 왜곡계수를 계산하는 딥러닝 네트워크를 제안하고자 한다. 또한, 단일 왜곡계수를 왜곡모델로 활용함으로써 layer 수를 크게 줄일 수 있는 경량화 네트워크를 제안한다.

• Geotechnical Engineering
• /
• v.14 no.1
• /
• pp.5-14
• /
• 1998

In refuse landfill, long-term settlement is considerably dependent upon the biological decomposition of refuse which is distinguished from typical soil behavior. Two equations are combined in order to model long-term settlement behavior of refuse landfill caused by mechanical secondary compression and secondary compression caused by the decomposition of biolegradable refuse. It is suggested that mechanical secondary compression is linear with respcet to the logarithm of time. In order to estimate the settlement that occurs due. to the decomposition of biodegradable refuse, a mathematical model is used which theoretically conoiders the decomposition process related to the solubilization stage of biodegradable refuse solid. This model is based on hydrolysis process and expressed as first order kinetics. The proposed model is applied to Lysimeter compression data of an old refuse. This paper intends to propose the simplest mathematical model which effectively represents settlement caused by the solubilization stage of biodegradable refuse solid on decomposition process.

• Communications of Mathematical Education
• /
• v.26 no.1
• /
• pp.137-154
• /
• 2012

Approximation' is one of central conceptions in calculus. A basic conception for explaining 'approximation' is 'tangent', and 'tangent' is a 'line' with special condition. In this study, we will study pedagogically these mathematical knowledge on the ground of a viewpoint on the teaching of secondary geometry, and in connection with these we will suggest the teaching program and the chief end for the probable teaching. For this, we will examine point, line, circle, straight line, tangent line, approximation, and drive meaningfully mathematical knowledge for algebraic operation through the process translating from the above into analytic geometry. And we will construct the stream line of mathematical knowledge for approximation from a view of modern mathematics. This study help mathematics teachers to promote the pedagogical content knowledge, and to provide the basis for development of teaching model guiding the mathematical knowledge. Moreover, this study help students to recognize that mathematics is a systematic discipline and school mathematics are activities constructed under a fixed purpose.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.18 no.1
• /
• pp.7-13
• /
• 2008

This paper suggests a Path-planning algorithm for mobile agents. While there are a lot of studies on the path-planning for mobile agents, mathematical modeling of complex environment which constrained by spatio-temporally is very difficult and it is impossible to obtain the optimal solutions. In this paper, an optimal path-planning algorithm based on the graphic technique is presented. The working environment is divided into two areas, the one is free movable area and the other is not permissible area in which there exist obstacles and spatio-temporally constrained, and an optimal solution is obtained by using a new algorithm which is based on the well known ACO algorithm.

• School Mathematics
• /
• v.11 no.2
• /
• pp.243-260
• /
• 2009

In this paper, we have designed a teaching unit for the learning mathematising of secondary pre-service teachers by exploring generalized fibonacci sequences. First, we have found useful formulas for general terms of generalized fibonacci sequences which are expressed as combinatoric notations. Second, by using these formulas and CAS graphing calculator, we can help secondary pre-service teachers to conjecture and discuss the limit of the sequence given by the rations of two adjacent terms of an m-step fibonacci sequence. These processes can remind secondary pre-service teachers of a series of some mathematical principles.

• Journal of the Korea Convergence Society
• /
• v.3 no.4
• /
• pp.35-44
• /
• 2012

In this study, a simulation program is developed in order to investigate non steady-state cornering performance of 6WD/6WS special-purpose vehicles. 6WD vehicles are believed to have good performance on off-the-road maneuvering and to have fail-safe capabilities. But the cornering performances of 6WS vehicles are not well understood in the related literature. In this paper, 6WD/6WS vehicles are modeled as a 18 DOF system which includes non-linear vehicle dynamics, tire models, and kinematic effects. Then the vehicle model is constructed into a simulation program using the MATLAB/SIMULINK so that input/output and vehicle parameters can be changed easily with the modulated approach. Cornering performance of the 6WS vehicle is analyzed for brake steering and pivoting, respectively. Simulation results show that cornering performance depends on the middle-wheel steering as well as front/rear wheel steering. In addition, a new 6WS control law is proposed in order to minimize the sideslip angle. Lane change simulation results demonstrate the advantage of 6WS vehicles with the proposed control law.

• Korean Journal of Food Science and Technology
• /
• v.36 no.2
• /
• pp.349-354
• /
• 2004

Predictive growth model of Vibrio parahaemolyticus in modified surimi-based imitation crab broth was investigated. Growth curves of V. parahaemolyticus were obtained by measuring cell concentration in culture broth under different conditions ($Initial\;cell\;level,\;1{\times}10^{2},\;1{\times}10^{3},\;and\;1{\times}10^{4}\;colony\;forming\;unit\;(CFU)/mL$; temperature, 15, 25 37, and $40^{\circ}C$; pH 6, 7, and 8) and applying them to Gompertz model. Microbial growth indicators, maximum specific growth rate (k), lag time (LT), and generation time (GT), were calculated from Gompertz model. Maximum specific growth rate (k) of V. parahaemolyticus increased with increasing temperature, reaching maximum rate at $37^{\circ}C$. LT and GT were also the shortest at $37^{\circ}C$. pH and initial cell number did not influence k, LT, and GT values significantly (p>0.05). Polynomial model, $k=a{\cdot}\exp(-0.5{\cdot}((T-T_{max}/b)^{2}+((pH-pH_{max)/c^{2}))$, and square root model, ${\sqrt{k}\;0.06(T-9.55)[1-\exp(0.07(T-49.98))]$, were developed to express combination effects of temperature and pH under each initial cell number using Gauss-Newton Algorism of Sigma plot 7.0 (SPSS Inc.). Relative coefficients between experimental k and k Predicted by polynomial model were 0.966, 0.979, and 0.965, respectively, at initial cell numbers of $1{\times}10^{2},\;1{\times}10^{3},\;and\;1{\times}10^{4}CFU/mL$, while that between experimental k and k Predicted by square root model was 0.977. Results revealed growth of V. parahaemolyticus was mainly affected by temperature, and square root model showing effect of temperature was more credible than polynomial model for prediction of V. parahaemolyticus growth.