• 한국위성정보통신학회논문지
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• 제7권1호
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• pp.92-96
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• 2012

본 논문은 복잡한 신호처리 기능을 포함하는 리턴 링크 복조 알고리즘이 낮은 SNR에서도 안정적으로 동작하도록 하기 위해 하드웨어에 적합하도록 설계하여 HDL로 구현하는 것을 목적으로 한다. 모의실험 결과 Uncoded BER $10^{-3}$ 지점에서의 Es/$N_0$가 이상적인 QPSK 신호 대비 0.5dB 이내로의 성능개선을 이룬 것을 확인할 수 있다. 또한 이에 대한 Fixed-Point Simulation 및 HDL 구현 성능이 모의실험 대비 차이가 없음을 확인할 수 있다.

• 오토저널
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• 제8권1호
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• pp.75-86
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• 1986

This paper describes a simulation program of intake and exhaust processes in a 4-stroke S.I. engine and also studies the relationship among various engine parameters under different engine speed and load conditions. This simulation program includes the engine cylinder model for the intake and exhaust processes and its formulation and evaluates the system characteristics such as inlet mass, pumping work and residual gas in the cylinder-which influence on power output, fuel economy and exhaust emissions. In order to evaluate the accuracy of the simulation program, predicted results were compared with the experimental data obtained on the 4-stroke, 4-cylinder gasoline engine and satisfactory agreement was obtained.

• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.61-69
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• 2010

This paper presents a study of a DFIG wind power generation system for real-time simulations. For real-time simulations, the Real-Time Digital Simulator (RTDS) and its user friendly interface simulation software RSCAD are used. A 2.2MW grid-connected variable speed DFIG wind power generation system is modeled and analyzed in this study. The stator-flux oriented vector control scheme is applied to the stator/rotor side converter control, and the back-to-back PWM converters are implemented for the decoupled control. The real-wind speed signal extracted by an anemometer is used for a realistic, reliable and accurate simulation analysis. Block diagrams, a mathematical presentation of the DFIG and a control scheme of the stator/rotor-side are introduced. Real-time simulation cases are carried out and analyzed for the validity of this work.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.9-12
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• 2005

The rapid thermal response (RTR) molding is a novel process developed to raise the temperature of mold surface rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly to the ejection temperature. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filing difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. In order to take into account the effects of thermal boundary conditions of the RTR mold, coupled analysis with transient heat transfer simulation is suggested and compared with conventional isothermal analysis. The proposed coupled simulation approach based on solid elements provides reliable thin wall flow estimation fur both the conventional molding and the RTR molding processes

• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.877-882
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• 2001

The solvent effects on the relative free energies of Eu3+ to Yb3+ ion mutation in solution have been investigated using a Monte Carlo simulation of statistical perturbation theory (SPT). Our results agree well with available data that were obtained by others. Particularly, the results of water (SPC/E) solvent are almost identical with experimental data. For the present Eu3+ and Yb3+ ions, the relative free energies of solvation vs. Born’s function of bulk solvents decrease with increasing Born’s function of bulk solvents. There is also good agreement between the calculated structural properties in this study and the published works obtained by computer simulation and experimental work.

• 한국항공운항학회지
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• 제27권3호
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• pp.1-14
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• 2019

Cooperative systems among various unmanned vehicles are widely used in various field and emerging. Unmanned vehicles are able to operate various missions without operator onboard and they are highly stable. Collaborative work of multiple unmanned vehicles is emphasized due to the difficulty of recent missions such as SEAD (Suppression of the Enemy Air Defenses), MUSIC (Manned Unmanned Systems Integration Capability), goldentime in the rescue mission. In this study, ROS and Pixhawk were proposed as a method of construction of a collaboration system and framework for an integrated simulation environment for heterogeneous unmanned vehicles is proposed. Totally 5 unmanned vehicles were set for the simulation for the observation of illegal fishing boats. This paper shows the feasibility of the cooperative system using ROS and Pixhawk through the simulation and the experiment.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.149-150
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• 2021

Earthwork is the starting work of construction process, which has the greatest impact on the productivity of the construction project among the works. However, it is difficult to derive accurate productivity becuase the earthwork plan is affected by geological condition of the jobsite. Therefore, a simulation model for productivity analysis of earthwork was developed using CYCLONE modeling method in this study. In this paper, simulation model was made considering the impact factors of earthwork productivity. The proposed model can be utilized for sensitivity analysis in future studies.

• 한국CDE학회논문집
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• 제21권1호
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• pp.9-19
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• 2016

Applying human engineering simulation to analyzing work capability and movements of operators during manufacturing is highly demanded. However, difficulty in modeling digital human required for simulation makes engineers to be reluctant to utilize human simulation for their tasks. This paper addresses such problem on human engineering simulation by developing the technology to automatize human modeling with multiple Kinects at different depths. The Kinects enable us to acquire the movements of digital human which are essential data for implementing human engineering simulation. In this paper, we present a system for modeling automation of digital human. Especially, the system provides a way of generating the digital model of workers' movement and position using multiple Kinects which cannot be generated by single Kinect. Lastly, we verify the effects of the developed system in terms of modeling time and accuracy by applying the system to four different scenarios. In conclusion, the proposed system makes it possible to generate the digital human model easily and reduce costs and time for human engineering simulation.

• 한국철도학회논문집
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• 제10권2호
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• pp.231-242
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• 2007

As railroad industry faces the new Renaissance era, effective and efficient maintenance methods for rolling stock operation are required with advanced railroad technology. All kinds of railroad systems such as high-speed long-distance train, metropolitan mass transit and light rail require systematic maintenance technology in order to maintain the safe railroad operation. Simulation models for regular operations of the example maintenance center are developed. In this study, standard maintenance procedures, layout, equipments, and number of workers of Siheung Metropolitan Railroad Maintenance Rolling Stock Depot are considered. The proposed simulation models are developed using simulation package ARENA. After simulation, four types of observations are analyzed. First, the bottleneck operation is identified. Second, the relationship between maintenance center size, number of workers and cycle time is analyzed. Third, the scheduling performances between PERT/CPM and Critical Chain Project Management(CCPM) are compared. Lastly, the simulation results according to worker's working coverage shows expanding the worker's coverage decreases the cycle time and increases throughput per train. However, workers are to be fully trained to do multiple skill work.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.3-8
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• 2006

The application of three-dimensional (3-D) CAD has been popularized for design and production and digital manufacturing has been spreading in many industrial fields. By simulation of the production process using 3-D digital models, which are the core of CIM (Computer Integrated Manufacturing) system, the efficiency and safety of production are improved at each stage of work, and optimization of manufacturing can be achieved. This paper firstly describes the concept of "simulation based production" in shipbuilding and also digital manufacturing; the 3-D CAD system is indispensable for effective simulation because ship structure is three dimensionally complex. By simulation, "computer optimized manufacturing" can be possible. The most effective fields of simulation in shipbuilding are in jobs where many parties have to cooperate, while existing two-dimensional drawings are hardly observed the whole structures due to interference between structures or equipment of complex shape. In this paper some examples of the successful application in IHIMU (IHI Marine United Inc.) are shown: assembly of a pipe unit, erection of a complex hull block, carriage of equipment, installation of a propeller, and access in an engine room.