• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.29-34
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• 2002

This study presents the process of the continuous-time system identification for unknown nonlinear systems. The Radial Basis Function(RBF) error filtering identification model is introduced at first. This identification scheme includes RBF network to approximate unknown function of nonlinear system which is structured by affine form. The neural network is trained by the adaptive law based on Lyapunov synthesis method. The identification scheme is applied to engine and the performance of RBF error filtering Identification model is verified by the simulation with a three-state engine model. The simulation results have revealed that the values of the estimated function show favorable agreement with the real values of the engine model. The introduced identification scheme can be effectively applied to model-based nonlinear control.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.702-704
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• 2022

자율주행 시뮬레이터를 위한 대체재로 게임 엔진을 통한 가상 환경 모의 연구가 수행되고 있다. 하지만 게임 엔진에서는 자율 주행에 필요한 센서를 기기에 맞게 사용자가 직접 모델링을 해줘야 하기 때문에 개발 비용이 크게 작용된다. 특히, Ray 를 활용한 3D LIDAR 는 GPU(Graphics Processing Unit) 사용량이 많은 작업이기 때문에 저비용 시뮬레이터를 위해서는 저비용 3D LIDAR 모의가 필요하다. 본 논문에서는 낮은 컴퓨터 연산을 사용하는 C++ 기반 3D LIDAR 모의 프레임 워크를 제안한다. 제안된 3D LIDAR 는 다수의 언덕으로 이루어진 비포장 Map 에서 성능을 검증 하였으며, 성능 검증을 의해 본 논문에서 생성된 3D LIDAR 로 간단한 LPP(Local Path Planning) 생성 방법도 소개한다. 제안된 3D LIDAR 프레임 워크는 저비용 실시간 모의가 필요한 자율 주행 분야에 적극 활용되길 바란다.

• The KIPS Transactions:PartD
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• v.12D no.7 s.103
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• pp.1007-1016
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• 2005

A key issue for process language design is balancing the need for semantic richness with the need for ease of use. Most process modeling languages fail to satisfy above two conflicting aspects, which is an impediment to the widespread adoption of process modeling languages in the software industry despite of a variety of software process language studies. This paper describes a process modeling language RAiSE attempting to resolve such problem and presents the result of applying RAiSE to a well-known benchmark process, ISPW-6 software process example. RAiSE provides rigorous, yet clear semantics through combing essential features in various modeling paradigms and defining them in a well-structured graphical notation. Process models represented in RAiSE are interpreted and enacted by process engine implemented using CLiPS, a rule based expert system tool.

• Spatial Information Research
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• v.9 no.2
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• pp.185-206
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• 2001

Cellular Automata(CA) have been investigated and utilized as a theoretical framework and/or methodology for analyzing and simulating the properties and behaviors of many complex systems in various physical science and engineering field. Due to the conceptual elegance and effectiveness of implementing spatio-temporal dynamic models and the compatibility with raster GISs, recently a variety of modeling works using both CA and GIS have been published in GIS fields Most of spatial dynamic models introduced in previous research, however, were very limited and furthermore integrated CA-GIS system for practical modeling purpose are not developed yet. This study aims to develop an integrated CA-GIS system in which a CA simulator is used as an analytical engine for GIS providing a multipurpose spatial dynamic modeling functionalities. This integrated CA-GIS system is anticipated radically enhancing the current lacking dynamic modeling functionalities of GIS and being utilized as an powerful and effective tool for practical spatial dynamic modeling research.

• The Journal of the Acoustical Society of Korea
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• v.30 no.5
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• pp.281-294
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• 2011

Physics-based sound synthesis usually requires high computational costs and this results in a restriction of its use in real-time applications. This motivates us to implement the sound synthesis algorithm of plucked-string instruments using multi-core processor architectures and determine the optimal processing element (PE) configuration for the target instruments. To determine the optimal PE configuration, we evaluate the impacts of a sample-per-processing element (SPE) ratio that is defined as the amount of sample data directly mapped to each PE on system performance and both area and energy efficiencies using architectural and workload simulations. For the acoustic guitar, the highest area and energy efficiencies are achieved at a SPE ratio of 5,513 and 2,756, respectively, for the synthesis of musical sounds sampled at 44.1 kHz. In the case of the classical guitar, the maximum area and energy efficiencies are achieved at a SPE ratio of 22,050 and 5,513, respectively. In addition, the synthetic sounds were very similar to original sounds in their spectra. Furthermore, we conducted MUSHRA subjective listening test with ten subjects including nine graduate students and one professor from the University of Ulsan, and the evaluation of the synthetic sounds was excellent.

• 한국지구물리탐사학회:학술대회논문집
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• 2009.10a
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• pp.75-80
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• 2009

Despite its flexibility to complex geometry, three-dimensional (3D) electromagnetic(EM) modeling schemes using finite element method (FEM) have been faced to practical limitation due to the resulting large system of equations to be solved. An efficient 3D FEM modeling scheme has been developed, which can adopt either direct or iterative solver depending on the problems. The direct solver PARDISO can reduce the computing time remarkably by incorporating parallel computing on multi-core processor systems, which is appropriate for single frequency multi-source configurations. When limited memory, the iterative solver BiCGSTAB(1) can provide fast and stable convergence. Efficient 3D simulations can be performed by choosing an optimum solver depending on the computing environment and the problems to be solved. This modeling includes various types of controlled-sources and can be exploited as an efficient engine for 3D inversion.

• Journal of the Korea Society for Simulation
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• v.23 no.4
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• pp.211-218
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• 2014

The Test and Evaluation (T&E) system became more important due to its advancement and complexity of the weapon system. Time and cost saving T&E related studies are in progress mainly with advanced countries. By utilizing the Modeling and Simulation (M&S) technology recently, we may save time and money. Also, overcome security and safety limitations. There are many M&S based research activities in South Korea but it is way behind of the system that some countries already have developed. i.e.; United States. This area of study requires new way of developing strategies in the T&E system of Korea. This study is to design the Operational T&E system for weapon systems based on modeling of processes. And we modeled the processes of operational performance evaluation through utilizing resources and performance modules of weapon systems and combined it with the simulation engine for 3D visualization. Through this, we propose the Operational T&E system for weapon systems based on modeling of processes that represent operational performances visually.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.157-159
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• 2004

본 논문에서는 분산 일시간 객체 엔진을 내장하는 TMO-LINUX/ARM 커널 상에서, 각종 센서 및 모터 제어로 구성되는 로봇 제어 시스템을 동적 분산 실시간 객체인 TMO로 모델링하고 구현하였다. TMO(Time-triggered Message-triggered Object)는 시간적 조건에 의해 구동되는 객체 내의 실시간 스레드와 메시지에 의해 구동되어 주어진 데드라인 안에 작업을 수행하는 메시지 구동 실시간 스레드들의 동적 멤버들로 구성되는 실시간 객체로, 외부의 입출력에 반응하며 내부 장치에 대한 실시간 작업을 병행해야 하는 로봇 제어 시스템에 대해 매우 적합한 모델이다. 본 논문에서는 이러한 로봇 제어 시스템 설계에의 TMO의 적용이 잘 정의되고 규격적인 설계 모델을 제공함을 보인다.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.564-569
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• 2001

본 논문은 기존의 3D게임엔진에 실시간으로 상호작용이 가능하고 3D MMORPG(Massive Multi-play Outline Role Playing Game) 게임에 적합한 가상공간을 표현하기 위한 필요한 기술을 분석하고 이를 활용하려 한다. 기존의 머드 게임에 3차원 기술적용하고, 3차원 물체를 모델링하는데 있어서 메쉬나 버텍스, 혹은 폴리곤으로 사실적인 지형처리와 렌드링 속도향상을 위하여 3차원 개체의 폴리곤을 동적으로 생성시키기 위한 방법으로 Height field처리 기법과 거리에 따라 다르게 모델링된 데이터를 선택적으로 사용하는 LOD(Level of Detail)처리기법과 가시성 판단이나 충돌 검출을 위한 입체 컬링 방법으로 옥트리를 이용하여 가상공간을 분해 하기 위한 자료 구조로 사용한다. 본 논문은 기존의 3차원 공간을 표현하기 위하여 사용되고 있는 옥트리 구조를 이용하여 공간을 분할하고, 이를 세부수준으로 나누어 처리하기 위한 LOD 개념을 이용하여 외부지형을 폴리곤으로 표현하는 방법에 대한 처리 기법을 제시하려고 한다.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.174-183
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• 2004

In this paper, the performance improvement and modeling of small onboard generator were described. As the characteristics of the field coil which are a major parameters of generator were improved, the system bandwidth could be increased, therefore the generator could also be satisfied with fast characteristic loads. Established the brief control model of the generator, it could be possible to do the analysis of generator performance, and improve the operational stability of the generator system using the control model.