• Journal of the Society of Naval Architects of Korea
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• v.61 no.4
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• pp.226-235
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• 2024

A method for quantifying the adaptability of ship maneuver scenarios for data-driven modeling of ship dynamics is developed based on the principal component analysis. A random maneuver scenario is suggested as a reference for ship dynamics, which can obtain the converged principal components of ship dynamics features by the Monte Carlo simulation. Principal components of conventional maneuver scenarios defined by the International Maritime Organization (IMO) are compared to that of the random maneuver. A conventional ship dynamics model for a container carrier vessel for four degrees of freedom dynamics is introduced to simulate the random and IMO maneuver scenarios. It is confirmed that the IMO tests follow the tendency of random maneuver scenario in terms of execution time and adaptability.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.576-579
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• 2008

The purpose of study is a development of the high reliance electric driven water-pump that fuction is forcing the movement of water using basic design, proto sample and test at the cooling system. It was important to supply a coolant quickly and accurately for the requirement of flow rate at the system when we carried out the designs for BLDC Moter, Controller and water pump(Impeller, Volute Casing, Sealing Device) First, we attained ours purpose that the target efficiency for water pump was over 40% and then we are doing the optimum design for Brushless Motor and Controller that its target is over 55% of efficiency.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.217-220
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• 2007

The purpose of study is a development of the high reliance electric driven water-pump that fuction is forcing the movement of water using basic design, proto sample and test at the cooling system. It was important to supply a coolant quickly and accurately for the requirement of flow rate at the system when we carried out the designs for BLDC Motor, Controller and water pump(Impeller, Volute Casing, Sealing Device) First, we attained ours purpose that the target efficiency for water pump was over 40% and then we are doing the optimum design for Brushless Motor and Controller that its target is over 55% of efficiency.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.394-403
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• 1991

This paper described the development of input driven multilayer perceptron(IDMLP) neural network and it's application to the Korean spoken digit recognition. The IDMPLP neural network used here and the learning algorithm for this network was proposed newly. In this model, weight value is integer and transfer function in the neuron is hard limit function. According to the result of the network learning for the some kinds of input data, the number of network layers is one or more by the difficulties of classifying the inputs. We tested the recognition of binaried data for the spoken digit 0 to 9 by means of the proposed network. The experimental results are 100% and 96% for the learning data and test data, respectively.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.208-210
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• 2005

A lot of conventional automotive components driven by mechanical power source are being replated with electrical ones to comply with the demands of market and customer, therefore the amount of electric energy used in a vehicle will be increased continuously. The increment of electric power demand causes interest on new higher power system such as 42V Power Net, and furthermore necessity for development of energy storage device is highlighted recently. This paper presents the design of the BLDC motor drive for Cooling Fan in 42V automotive system. Test results confirmed the feasibility of the proposed motor drive system design.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.6
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• pp.39-46
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• 2010

Linear induction motor is adopted as an actuator of the planar stage. An inherently poor characteristic at zero or ultra-low speed zone of the induction motor is remarkably improved due to a recent development of power electronic semiconductor technology and a spatial vector control theory. At present, a servo response speed of the induction motor reaches 90 percent of one of PM synchronous or BLDC motor. Specially, as a secondary of the induction motor can be constructed using uniform conducting sheets, there is no periodic force ripple as in PM motors. So, the induction motor can be superior to another driving means under a certain condition. This paper discusses the overall development procedure of non-contact planar stage with a big workspace using linear induction motors.

• 연구논문집
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• s.29
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• pp.57-67
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• 1999

This paper presents the status quo of the development of a piecewise bendable switch system for the urban transit MagLev. MagLev system as well as railroad requires switch systems to reach its destination. Requirements of the switch system for commercial lines are high speed operation satisfying about 2-3 minute headway and system reliability, etc. Parallel moving type switch system was installed on the test track of urban transit MagLev in KIMM. In this system, switch operation from one position to another can be done in about 90 seconds. Therefore, we concluded that this system can not satisfy the headway for the commercial lines. We decided to develop a high speed piecewise bendable switch system in which switching can be done in 20 seconds. Designed switch system is very complicated in view of operating mechanism. It consists of 11 segmented girder beams driven by hydraulic cylinders. To gain the idea of a piecewise bendable switch system, we manufactured and tested a 1/5 scale switch model. We are going to construct a full scale piecewise bendable switch system next year.

• Journal of Mechanical Science and Technology
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• v.19 no.8
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• pp.1621-1631
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• 2005

In this paper, making the best use of the features of the electro-rheological (ER) valve, a two-port pressure control valve using ER fluids is proposed and manufactured. The ER-Valve characteristics are evaluated by changing the intensity of the electric field and the number of electrode. As only with electrical signal change to the ER-Valve in which ER fluid flowing, ER fluid flow is controlled, so development of simple ER-Valves have been tried. The ER-Valves and pressure drop check method are considered to be applied to the fluid power industry. Using the manufactured pressure control valve, a one-link manipulator with FHA (Flexible Hydraulic Actuator) is driven. As a result, it is experimentally confirmed that the pressure control valve using ER fluids is applicable to use in driving actuator. If it applies characteristics of the ER fluids, it will be able to apply in the control system for the ER Valve which occurs from industrial controller. After having durability test, shear stress increased regularly because of starch particles crushed by pump and particle size that was almost the same. Moreover, Ra of copper electrode increased about 1.56 times rather than before those of performing durability test, and Rz increased about 2.2 times.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.199-206
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• 2006

Automatic grease lubricator is equipment that provides adequate amount of fresh grease constantly to the shaft and the bearings of machines. It minimizes the friction heat and reduces the friction loss of machines to the least. This research is to develop automatic grease lubricator by gear driven mechanism with controlled operation time. The ultimate design of this equipment is to lubricate an adequate amount of grease by a simple switch clicking according to the advanced set cycle. The backlash of the gear was minimized to increase the output power. To increase the power of gear mechanism, the binding frequency and the thickness of the coil were changed. To control the rotating cycles of the main shaft according to its set numbers, different resistance and chips were used to design the circuit to controls electrical signals with pulse. The body of the lubricator was analyzed by stress analysis with different constructed angle. The stress analysis for differing loading pressures applied to the exterior body of grease lubricator due to the setup angle, was found that the maximum stress was distributed over the outlet part where the grease lubricator suddenly narrowed contracts. Digital mock-up was analyzed and the rapid prototyping(RP) trial products were tested with PCB circuit and grease. The evaluation of the outlet capacity for RP trial products was conducted, because the friction caused by the outlet on the wall surface was an important factor in the operation of the equipment. Finally, the finishing process was applied to decrease the roughness of the surface to a comparable level and was able to test the performance examination for the product.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.99-110
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• 2001

Open-ended pipe piles are often used for the foundations of both land and offshore structures because of their relatively low driving resistance. In this study, load tests were performed on model pipe piles installed in calibration chamber samples in order to investigate the effects of pile installation method on soil plugging and bearing capacity. Results of the test program showed that the incremental filling ratio (IFR), which is used to indicate the degree of soil plugging in open-ended piles, decreased (i) with increasing hammer weight for the same driving energy and (ii) with increasing hammer weight at the same fall height. The base and shaft resistance of the piles were observed to increase (i) with increasing hammer weight for the same driving energy and (ii) with increasing hammer weight at the given same fa11 height. The jacked pile was found to be have higher bearing capacity than an identical driven pile under similar conditions, mostly due to the more effective development of a soil plug in jacking than in driving.