• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.335-342
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• 2007

A propulsion and lift shafting system in an air cushion vehicle is flexible multi-elements system which consists of two aeroderivative gas turbines with own bevel gears, four stage lift fan reduction gear, two stage propulsion reduction gear air propellers and high capacity of lifting fans. In addition, the system includes the multi-branched shafting with multi-gas turbine engines and thin walled shaft with flexible coupling. Such a branched shafting system has very intricate vibrating characteristics and especially, the thin walled shaft with flexible couplings can lower the torsional natural frequencies of shafting system to the extent that causes a resonance in the range of operating revolution. In this study, to evaluate vibrational characteristics some analytical methods for the propulsion and lift shafting system are studied. The analysis, including natural frequencies and mode shapes, for five operation cases of the system is conducted using ANSYS code with a equivalent mass-elastic model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.792-812
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• 2022

Multi-agent systems often need to achieve the goal of learning more effectively for a task through coordination. Although the introduction of deep learning has addressed the state space problems, multi-agent learning remains infeasible because of the joint action spaces. Large-scale joint action spaces can be sparse according to implicit or explicit coordination structure, which can ensure reasonable coordination action through the coordination structure. In general, the multi-agent system is dynamic, which makes the relations among agents and the coordination structure are dynamic. Therefore, the explicit coordination structure can better represent the coordinative relationship among agents and achieve better coordination between agents. Inspired by the maximization of social group utility, we dynamically construct a factor graph as an explicit coordination structure to express the coordinative relationship according to the utility among agents and estimate the joint action values based on the local utility transfer among factor graphs. We present the application of such techniques in the scenario of multiple intelligent vehicle systems, where state space and action space are a problem and have too many interactions among agents. The results on the multiple intelligent vehicle systems demonstrate the efficiency and effectiveness of our proposed methods.

• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.1-8
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• 2023

This paper presents the control strategy of Auto-leveling equipment (ALE) of Multi-function radar (MFR) for vehicle using Embedded System. MFR implements surveillance patrol missions such as surface-to-air missiles and fighters with constant rotation. ALE consists of 4 Auto-leveling modules (ALM) and retains the stability with maintaining level. The gradient of vehicle can be measured and controlled by embedded systems. This paper contributes for improvement the system design with the ALM 1 set modeling. The validity of the modeling is verified using MATLAB/Simulink.

• Journal of Auto-vehicle Safety Association
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• v.14 no.1
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• pp.32-38
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• 2022

In the automobile industry, lamps are frequently used as a mean to emphasize each company's brand identity. Therefore, many detailed design models have emerged in order to realize a differentiated image in preparation for competitive vehicles. Among them, the design of a multi compartment lighting image concept that realizes light divided in multiple space also being introduced by various manufacturers. In this study, in order to solve the problem of cost and weight rise that the existing multi compartment image lamp has, using TRIZ method such as functional analysis modeling and trimming. Through this process, an idea to minimize cost and weight was derived. As the idea was designed in detail, the formation of light did not go as desired, and the diffusion of light also proceeded differently than intended. In order to overcome this problem, a new concept of corrosion and diffusion structure was applied. Eventually, it overcomes various problems and successfully applied it to a real vehicle. The idea was actually reflected in the "Santa Fe" model. Later, the media focused on the lamps to which the idea was applied, and contributed to the sale of a large number of vehicles by providing consumers with a new light sensibility. During the research process, it was possible to secure a number of patents and knowledge of new design concepts.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1244-1255
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• 2015

This paper presents a new multi-machine robust control based on an electric differential system for electric vehicle (EV) applications which is composed of four in-wheel permanent magnet synchronous motors. It is based on a new master-slave direct torque control (DTC) algorithm, which is used for the control of bi-machine traction systems based on a speed model reference adaptive system observer. The use of an electric differential in the design of a new EV constitutes a technological breakthrough. A classical system with a multi-inverter and a multi-machine comprises a three-phase inverter for each machine to be controlled. Another approach consists of only one three-phase inverter for several permanent magnet synchronous machines. The control of multi-machine single-inverter systems is the subject of this study. Several methods have been proposed for the control of multi-machine single-inverter systems. In this study, a new master-slave based DTC strategy is developed to generate an electric differential system. The entire system is simulated by Matlab/Simulink. The simulation results show the effectiveness of the new multi-machine robust control based on an electric differential system for use in EV applications.

• Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.179-190
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• 2016

A kind of modified epoxy resin sheet molding compounds of the impeller has been designed. Through the test, the non-metal impeller has a better environmental aging performance, but must do the waterproof processing design. In order to improve the stability of the impeller vibration design, the influence of uncertainty factors is considered, and a multi-objective robust optimization method is proposed to reduce the weight of the impeller. Firstly, based on the fluid-structure interaction, the analysis model of the impeller vibration is constructed. Secondly, the optimal approximate model of the impeller is constructed by using the Latin hypercube and radial basis function, and the fitting and optimization accuracy of the approximate model is improved by increasing the sample points. Finally, the micro multi-objective genetic algorithm is applied to the robust optimization of approximate model, and the Monte Carlo simulation and Sobol sampling techniques are used for reliability analysis. By comparing the results of the deterministic, different sigma levels and different materials, the multi-objective optimization of the SMC molding impeller can meet the requirements of engineering stability and lightweight. And the effectiveness of the proposed multi-objective robust optimization method is verified by the error analysis. After the SMC molding and the robust optimization of the impeller, the optimized rate reached 42.5%, which greatly improved the economic benefit, and greatly reduce the vibration of the ventilation system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.711-714
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• 2001

As the life cycle of the vehicle become shorter, the method that reduce the development time of new model become more important. In this reason, the development of the simulator that provides similar environment with the actual vehicle road characteristics is increasing. In this paper, the multi-axis simulator is designed and analyzed by kinematic method. The simulator has a function simulating the 3 load elements; vertical, longitudinal, and lateral force respectively and simultaneously. The result of this paper can be used for developing the multi-axis simulator linkage.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.741-746
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• 2007

In this study, transfer path identification and output estimation are simulated by multi-dimension spectral analysis method (MDSA). Multi -input/single-output system give expression the vehicle suspension which each inputs are correlated reciprocally. In case of correlating with inputs, the system needs separating the each input signal by MDSA. Main simulations are about finding effective input by coherent output spectrum and selecting optimal input's number by multiple coherence function. Also, by shielding transfer path of each input, transfer path characteristic is identified in terms of overall integrated contribution level.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.8-19
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• 2023

This paper presents advancement in multi- unmanned aerial vehicle (UAV) cooperative area surveillance, focusing on optimizing UAV route planning through the application of genetic algorithms. Addressing the complexities of comprehensive coverage, two real-time dynamic path planning methods are introduced, leveraging genetic algorithms to enhance surveillance efficiency while accounting for flight constraints. These methodologies adapt multi-UAV routes by encoding turning angles and employing coverage-driven fitness functions, facilitating real-time monitoring optimization. The paper introduces a novel path planning model for scenarios where UAVs navigate collaboratively without predetermined destinations during regional surveillance. Empirical evaluations confirm the effectiveness of the proposed methods, showcasing improved coverage and heightened efficiency in multi-UAV path planning. Furthermore, we introduce innovative optimization strategies, (Foresightedness and Multi-step) offering distinct trade-offs between solution quality and computational time. This research contributes innovative solutions to the intricate challenges of cooperative area surveillance, showcasing the transformative potential of genetic algorithms in multi-UAV technology. By enabling smarter route planning, these methods underscore the feasibility of more efficient, adaptable, and intelligent cooperative surveillance missions.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.51.2-51
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• 2001

A vehicle driving simulator is a virtual reality device which makes a human being feel as if the one drives a vehicle actually. The driving simulator is effectively used for studying interaction of a driver-vehicle and developing the vehicle system of new concepts. The driving simulator consists of a motion platform, a motion controller, a visual and audio system, a vehicle dynamic analysis system, a vehicle operation system and etc. The vehicle dynamic analysis system supervises overall operation of the simulator and also simulates dynamic motion of a multi-body vehicle model in real-time. In this paper, the main procedures to develop the driving simulator are classified by 4 parts. First, a vehicle motion platform and a motion controller, which generates realistic motion using a six degree of freedom Stewart platform driven hydraulically. Secondly, a visual system generates high fidelity visual scenes which are displayed on a screen ...