• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.150-155
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• 1997

Modelling and Simulation of the activation process for the myocardium is meaningful to understand special excitation conduction system in the heart and to study cardiac functions. In this paper, we propose two dimensional cellular automata model for the activation process of the myocardium and simulated by means of discrete time and discrete event algorithm. In the model, cells are classified into anatomically similar characteristic parts of heart; SA node, internodal tracks, AV node, His bundle, bundle branch and four layers of the ventricular muscle, each of which has a set of cells with preassigned properties, that is, activation time, refractory duration and conduction time between neighbor cell. Each cell in this model has state variables to represent the state of the cell and has some simple state transition rules to change values of state variables executed by state transition function. Simulation results are as follows. First, simulation of the normal and abnormal activation process for the myocardium has been done with discrete time and discrete event formalism. Next, we show that the simulation results of discrete time and discrete event cell space model is the same. Finally, we compare the simulation time of discrete event myocardium model with discrete time myocardium models and show that the discrete event myocardium model spends much less simulation time than discrete time myocardium model and conclude the discrete event simulation method Is excellent in the simulation time aspect if the interval deviation of event time is large.

• Korean Journal of Computational Design and Engineering
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• v.5 no.4
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• pp.327-335
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• 2000

The spent fuel rod extracting machine is automatically operated in high radioactive environment, so high reliability of operation is required. In this paper, to enhance the reliability of this machine by providing a close monitoring capability. a real time graphic simulation method is suggested. This method utilizes conventional IGRIP (Interactive Graphics Robot Instruction Program) 3D graphic simulation tool to visualize and simulate the 3D graphic model of this machine. Also, the dedicated protocol is defined for transmission of the operational data of the machine. The real time graphic simulation is realized by developing the socket module between a graphic workstation and a machine control computer through the TCP/IP network and by dividing the 3D graphic simulation GSL(Graphic Simulation Language) program as a small sized sub routine. The suggested method is implemented while automatically operating the rod extracting machine. The result of implementation shows that the real time 3D graphic simulation is well synchronized with the actual machine according to the operational data.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.71-80
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• 2008

In this study, a simulation framework, which can support developing various simulation systems for the improvement of process planning in shipbuilding such as the block erection, the block turn-over, and so on, is proposed. In addition, a simulation kernel, which is a key component of the simulation framework, is implemented according to the concept of the combined discrete event and discrete time simulation. To evaluate the efficiency and applicability of the proposed simulation framework, it is applied to the block erection process in shipbuilding. The result shows that the proposed simulation framework can provide the consistent, integrated development environment for a simulation system, as compared with existing studies and commercial simulation systems.

• Proceedings of the Korea Society for Simulation Conference
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• 2004.05a
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• pp.109-117
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• 2004

In this paper, we consider the aortic sinus baroreceptor, which is the most representative baroreceptor sensing the variance of pressure in the cardiovascular system, and propose heart activity control model to observe the effect of delay time in heart period and stroke volume under the regulation of baroreflex in the aortic sinus. The proposed heart activity baroreflex regulation model contains electric circuit sub-model. We constituted the time delay sub-model to observe sensitivity of heart activity baroreflex regulation model by using the variable value to represent the control signal transmission time from the output of baroreflex regulation model to efferent nerve through central nervous system. The simulation object of this model is to observe variability of the cardiovascular system by variable value in time delay sub-model. As simulation results, we observe three patterns of the cardiovascular system variability by the time delay, First, if the time delay over 2.5 second, aortic pressure and stroke volume and heart rate is observed nonperiodically and observed. Finally, if time delay under 0.1 second, then heart rate and aortic pressure-heart rate trajectory is maintained in stable state.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.187-187
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• 2000

This paper presents the comparison of Euler-Rodrigues quaternion and Euler Angles using attitude kinematics for aircraft flight simulation. It is hard for PC-Level to accomplish real-time simulation. The purpose of this paper is to accomplish real-time simulation of the aircraft dynamics modeling parts and the graphics parts. The computation time is more reduced in case of applying quaternions than Euler Angles. This paper provides a quaternions algorithm and it's applications for the real-time simulation.

• Journal of the Korea Society for Simulation
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• v.12 no.2
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• pp.45-53
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• 2003

This paper presents a retargetable compiled assembly simulation technique for fast ASIP(application specific instruction processor) simulation. Development of ASIP which satisfies design requirements in various fields of applications such as telecommunication, wireless network, etc. needs formal design methodology and high-performance relevant software environments such as compiler and simulator In this paper, we employ the architecture description language(ADL) named ${HiXR}^2$ to automatically synthesize an instruction-level compiled assembly simulator. A compiled simulation has benefit of time efficiency to interpretive one because it performs instruction fetching and decoding at compile time. Especially, in case of assembly simulation, instruction decoding is usually a time-consuming job(string operation), so the compiled simulation of assembly simulation is more efficient than that of binary simulation. Performance improvement of the compiled assembly simulation based on ${HiXR}^2$ is exemplified with an ARM9 architecture and a CalmRISC32 architecture. As a result, the compiled simulation is about 150 times faster than interpretive one.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.519-522
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• 1998

The Constructive Battle simulation Model is very important to the recent military training for the substitution of the field training. However, real battlefield systems operate under rea-time conditions, they are inherently distributed, concurrent and dynamic. In order to reflect these properties by the computer-based simulation systems which represent real world processes, we have been developing constructive simulation model for several years. The constructive simulation system is one of the famous real-time system software, nd the one common feature of all real-time systems is defined as the correctness of the system depend not only on the logical result of computation, but also on the time at which the results are produced. Conventionally, scheduling and resource allocation activities which have timing constraints are major problem of real-time computing systems. To overcome these constraints, we elaborated on these issues and developed the simulation system on commercially available hardware and operating system with lock-free resource allocation scheme and rae monotonic scheduling.

• Structural Engineering and Mechanics
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• v.75 no.4
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• pp.425-434
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• 2020

Practical non-synoptic fluctuating wind often exhibits nonstationary features and should be modeled as nonstationary random processes. Generally, the coherence function of the fluctuating wind field has time-varying characteristics. Some studies have shown that there is a big difference between the fluctuating wind field of the coherent function model with and without time variability. Therefore, it is of significance to simulate nonstationary fluctuating wind field with time-varying coherent function. However, current studies on the numerical simulation of nonstationary fluctuating wind field with time-varying coherence are very limited, and the proposed approaches are usually based on the traditional spectral representation method with low simulation efficiency. Especially, for the simulation of multi-variable wind field of large span structures such as transmission tower-line, not only the simulation is inefficient but also the matrix decomposition may have singularity problem. In this paper, it is proposed to conduct the numerical simulation of nonstationary fluctuating wind field in one-spatial dimension with time-varying coherence based on the wavenumber-frequency spectrum. The simulated multivariable nonstationary wind field with time-varying coherence is transformed into one-dimensional nonstationary random waves in the simulated spatial domain, and the simulation by wavenumber frequency spectrum is derived. So, the proposed simulation method can avoid the complicated Cholesky decomposition. Then, the proper orthogonal decomposition is employed to decompose the time-space dependent evolutionary power spectral density and the Fourier transform of time-varying coherent function, simultaneously, so that the two-dimensional Fast Fourier transform can be applied to further improve the simulation efficiency. Finally, the proposed method is applied to simulate the longitudinal nonstationary fluctuating wind velocity field along the transmission line to illustrate its performances.

• Journal of Drive and Control
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• v.16 no.1
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• pp.22-28
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• 2019

This paper develops ABS braking real - time simulator to develop vehicle braking system by simulation. Recently, real-time simulation is widely used in the development of vehicles to decrease development time. In the field of electronic braking, real-time simulation is actively underway. In order to simulate electronic braking model in real time, a vehicle model, a hydraulic model, and a control S/W model are required. These models must be calculated in one platform. Therefore, in this paper, a vehicle model composed of CarSim and a hydraulic model composed of SimulationX using S/W in actual ABS controller was developed as a Simulink model base and linked with Matlab real time model. Using this real-time model, design effects of the electronic braking controller were simulated according to road surface condition to verify its operability.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.3
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• pp.146-152
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• 2004

Cost effective simulation schemes for Wind Power Generation Systems (WPGS) considering wind turbine types, generators and load capacities have been strongly investigated by researchers. As an alternative, a true weather condition based simulation method using a real-time digital simulator (RTDS) is experimented in this paper for the online real-time simulation of the WPGS. A stand-alone WPGS is, especially, simulated using the Simulation method for WPGS using Real Weather conditions (SWRW) in this work. The characteristic equation of a wind turbine is implemented in the RTDS and a RTDS model component that can be used to represent any type of wind turbine in the simulations is also established. The actual data related to weather conditions are interfaced directly to the RTDS for the purpose of online real-time simulation of the stand-alone WPGS. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation scheme. The results also signify that the cost effective verification of efficiency and stability for the WPGS is possible by the proposed real-time simulation method.