• Journal of applied mathematics & informatics
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• 제8권1호
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• pp.165-180
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• 2001

This paper presents a new difference scheme for numerical solution of stiff system of ODE’s. The present study is mainly motivated to develop an absolutely stable numerical method with a high order of approximation. In this work a double implicit A-stable difference scheme with the sixth order of approximation is suggested. Another purpose of this study is to introduce automatic choice of the integration step size of the difference scheme which is derived from the proposed scheme and the one step scheme of the fourth order of approximation. The algorithm was tested by means of solving the Kreiss problem and a chemical kinetics problem. The behavior of the gas explosive mixture (H₂+ O₂) in a closed space with a mobile piston is considered in test problem 2. It is our conclusion that a hydrogen-operated engine will permit to decrease the emitted levels of hazardous atmospheric pollutants.

• 한국수학사학회지
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• 제29권6호
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• pp.353-363
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• 2016

In mathematical population ecology which is an academic field that studies how populations of biological species change as times flows at specific locations in their habitats, PDE models have been studied in many aspects and found to have different properties from the classical ODE models. And different approaches to PDE type models in mathematical biology are still being tried currently. This article investigate various forms to express diffusion effects and review the history of PDE models involving diffusion terms in mathematical ecology. Semi-linear systems representing the spatial movements of each individual as random simple diffusion and quasi-linear systems describing more complex diffusions reflecting interspecific interactions are studied. Also it introduce a few of important problems to be solved in this field.

• 한국정밀공학회지
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• 제14권8호
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• pp.108-114
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• 1997

A simple and efficient method is presented for the dynamics of interconnected flexible beams having large rigid body rotations. A simple mass matrix is obtained by interpolating the displacements in the global inertia frame, and the elastic force is also simply computed by using linear finite element technique with the moving frame attached to the beam. For the beams connected by revolute joints, kinematic constraints and relative rotations between the beans are not required and the equations of motions are time integrated by a simple ODE technique. Numerical simulations are conducted to demonstrate the accuracy and efficiency of the present technique.

• 한국CDE학회논문집
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• 제14권2호
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• pp.69-76
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• 2009

The development of a simulation system requires many sub modules such as a dynamic module, a visualization module, etc. If a different freeware is used for each sub modules, it is hard to develop the simulation system by incorporating them because they use their own data structures. To solve this problem, a high-level data structure, called Dynamics Scene Graph Data structure (DSGD) is proposed, by wrapping data structures of two freeware; an Open Dynamics Engine (ODE) for the dynamic module and an Open Scene Graph (OSG) for the visualization module. Finally, to evaluate the applicability of the proposed data structure, it is applied to the block erection simulation in shipbuilding. The result shows that it can be used for developing the simulation system.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제17권2호
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• pp.129-138
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• 2013

A spatio-temporal models as systems of ODE which describe two-species Beddington - DeAngelis type predator-prey system living in a habitat of two identical patches linked by migration is investigated. It is assumed in the model that the per capita migration rate of each species is influenced not only by its own but also by the other one's density, i.e. there is cross diffusion present. We show that a standard (self-diffusion) system may be either stable or unstable, a cross-diffusion response can stabilize an unstable standard system and destabilize a stable standard system. For the diffusively stable model, numerical studies show that at a critical value of the bifurcation parameter the system undergoes a Turing bifurcation and the cross migration response is an important factor that should not be ignored when pattern emerges.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제25권4호
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• pp.262-295
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• 2021

This paper introduces mono-implicit general linear methods, a special class of general linear methods, which are implicit in the output solution for the numerical integration of differential algebraic equations. We show how L-stable inherent Runge-Kutta members can be derived. The procedures for implementation have been discussed. The numerical test on the problem considered shows that the methods have improved accuracy when compared to RADAU IIA and the results from MATLAB ode15s, which have been taken as our reference solution.

• Journal of applied mathematics & informatics
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• 제40권5_6호
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• pp.1199-1215
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• 2022

This article aims to study the dynamical behaviours of a two species model in which non-selective harvesting of a prey-predator system by using a reasonable catch-rate function instead of usual catch-per-unit-effort hypothesis is used. A system of two ordinary differential equations(ODE's) has been proposed and analyzed with the predator functional response to prey density is considered as Hassell-Varley type functional responses to study the dynamics of the system. Positivity and boundedness of the system are studied. We have discussed the existence of different equilibrium points and stability of the system at these equilibrium points. We also analysed the system undergoes a Hopf-bifurcation around interior equilibrium point for a various parametric values which has very significant ecological impacts in this work. Computer simulation are carried out to validate our analytical findings. The biological implications of analytical and numerical findings are discussed critically.

• 한국게임학회 논문지
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• 제9권5호
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• pp.43-52
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• 2009

본 연구는 게임 물리 엔진을 실시간 물리 기술의 관점으로 고찰한다. 실시간 물리 기술이란 물리 시뮬레이션 기술을 게임에 적용하기 위해서 간략화 하는 기술을 말한다. 조사 대상으로 상용 물리 엔진인 Havok Physics SDK와 NVIDIA PhysX SDK를 선택하였고, 오픈 소스기반 물리 엔진인 ODE와 Bullet을 선택하였다. 그 결과 물리 엔진은 강체 역학, 변형체 시뮬레이션, 유체 시뮬레이션을 구현하고 있었고, 실시간 시뮬레이션을 위해서 수식의 간략화, 충돌 처리의 효율성 재고 등 소프트웨어 측면의 기술과 멀티 코어 CPU의 이용, PPU, GPU 활용 등 병렬처리 하드웨어 기술을 사용하고 있었다.

• Journal of the Korean Wood Science and Technology
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• 제47권4호
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• pp.451-458
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• 2019

Jabon (Anthocephalus cadamba Miq.) is a fast-growing species that exhibits a lower natural resistance than that exhibited by the timber sourced from natural forests. Jabon's resistance to termite attack can be improved by impregnating its wood structure with poisonous organic materials. This study examined jabon's resistance to termite attack when impregnated with wood vinegar and an animal adhesive. The wood specimens were impregnated using sengon wood vinegar and an animal adhesive (8% and 10%, respectively) using a vacuum pressure machine. The specimens were tested for their resistance to subterranean and dry-wood termites according to Indonesian National Standard (SNI 7207-2014). The results denoted that jabon impregnated with wood vinegar and an animal adhesive concentration of at least 8% with the addition of 4% borate was effective to resist termite attacks. The impregnated jabon exhibited a lower weight loss and higher termite mortality when compared with those exhibited by the control specimens. Thus, the resistance class improved from class IV to class I.

• 한국콘텐츠학회논문지
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• 제18권1호
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• pp.289-304
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• 2018

보수와 진보, 이념적 갈등이 빚어내는 정치 정서의 팬덤현상은 문화매체인 영화를 해석하고 수용하는 데에 있어 우리사회의 갈등을 증폭시키는 요인이 되고 있다. 이 글은 우리나라 정치의식구조가 왜 팬덤화되고 있나, 무엇이 영화 수용을 정치 이념의 논란의 중심에 서게 하였는가, 그렇다면 바람직한 영화 수용의 태도는 무엇인가를 점검해 보고자 수행되었다. 당시 영화를 두고 보수와 진보의 논란이 되었던 <변호인>,(2013)과 <국제시장>,(2014) 관련 논문과 기사 그리고 인터넷상의 논쟁들을 면밀히 살펴보는 담론분석을 실시하였다. 연구 결과, 첫째, 보수 진보 양진영은 두 영화를 해석하고 수용함에 있어서 다른 시선으로 같은 세계를 보고 있으며, 두 영화의 공식기억을 정치정서의 양극화와 기억투쟁의 이데올로기, 진영화를 구축하는 기재로 이용하고 있다는 것을 알 수 있었다. 둘째, 근현대사에 대한 합의된 기억의 구성이 되지 못함으로써 양세력 간에 서로의 공과를 인정치 않으며 자기 진영의 의미와 가치성만을 외치는 이기성이 갈등을 증폭시키고 있었다. 셋째, 영화 해석과 의미생산은 결국 관객들의 몫이며 거기에는 다양성이 중요한 가치성을 지닌다. 영화 수용은 관객 개인들이 현재의 현실에서 어떻게 해석하고 이상을 이성적으로 성찰하는 계기로 삼는 것이 바람직한 태도일 것이다.