• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 추계학술대회 논문
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• pp.150-155
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• 1996

This paper presents a new approach to the design of self-tuning adaptive control system that is robust to the changing dynamic configuration as well as to the load variation factors using digital signal processors for robot manipulators. TMS3200C50 is used in implementing real-time adaptive control algorithms provide advanced performance for robot manipulator. In this paper an adaptive control scheme is proposed in order to design the pole-placement self-tuning controller which can reject the offset due to any load disturbance without a detailed description of robot dynamics. parameters of discrete-time difference model are estimated by the recursive least-square identification algorithm and controller parameters are detemined by the pole-placement method. Performance of self-tuning adaptive controller is illusrated by the simulation and experiment for a SCARA robot.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.235-239
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• 2001

The bogie of high speed freight car running on conventional line is welded bogie modeled on Y25 bogie developed in Europe. Y25 bogie has speed limit of 110km/h. But it has limiting factors to speed-up as increasing maintenance cost and friction parts pedestal. And also it was reported that cracks are found in the parts where center beam meet bolster and endbeam near bracket for braking part. This study includes stress analysis improved structure of welded bogie for strength evaluation by numerical method and experimental method. According to the study, new configuration bogie shows improvement in strength.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.123-128
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• 2007

To predict the fire and smoke hazards of rail car with a evacuation model is essential for achieving life safety of all passengers in the event of fire. Currently, more than 30 different evacuation models are available and expected increasing demand in high population density areas as a metro train station. This paper includes brief history of evacuation models and review some key factors of design egress scenario, these are pre-movement time, egress route, location of fire, overturned carriage, and configuration of rail car. Applying the egress model for rail passenger car, users need to confirm the model's ability of physiological, psychological responses effecting to pre-movement time of individual or crowd unit, representation of complexity of carriage layout, and evaluation of effects of smoke.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.110-116
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• 1997

The tribological behaviour of WS$_2$ solid lubricant was investigated using a ball-on-disk type tester. The WS$_2$ powder was spray-coated at room temperature and the effects of specimen configuration, atmosphere, applied load and rotating spccd on the friction coefficient was examined. WS$_2$ coated ball and disk showed the lowest friction coefficient of 0.05 in the nitrogen atmosphere under 0.3 kgf and 100 rpm, whereas relatively high coefficient of 0.1 - 0.15 was observed in air atmosphere. This confirmed that the spray-coated WS$_2$ solid lubricant was effective in reducing the friction coefficient and improving wear life in nitrogen atmosphere.

• Journal of Welding and Joining
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• 제21권6호
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• pp.26-32
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• 2003

Arc welding process has indicated that it suffers from many flaws. It's because requirement of products is diverse and factors which affects the quality is also various. Therefore, in order to stabilize the welding process, it is important to choose a proper welding machine for the each process, and to evaluate the welding process capability of each machine. In this study, rational and simple index to evaluate the welding machine was set the coefficient of resistance variation through the arc stability examination such as spatter generation weight and bead configuration uniformity etc. And the method to evaluate the process capability index was developed by application of 6$\sigma$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.671-672
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• 2008

Hybrid intelligent technique is used in ship steering control. It can make full use of the advantage of all kinds of intelligent algorithms. This provides an efficient way for this paper. An RBF neural network and GA optimization are employed in a fuzzy neural controller to deal with the nonlinearity, time varying and uncertain factors. Utilizing the designed network to substitute the conventional fuzzy inference, the rule base and membership functions can be auto-adjusted by GA optimization. The parameters of neural network can be decreased by using union-rule configuration in the hidden layer of the network. The ship control quality is effectively improved in case of appending additional sea state disturbance. The performance of controller is evaluated by the system simulation using Matlab.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.502-505
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• 2008

Due to continuous difficulty of human power supply, it is necessary to develop an equipment which is good to saving cost and time at a construction site. A quick pipe coupling method is the kind of mechanical joint system using split-sleeve and sealing-pad at pipe groove without welding. In hence, it provides restrained pipe joint which is simple, safe, and dependable without environmental pollutions. It is more useful scheme than the other ones. The purpose of this study is to find out the main design factors and the optimum shape of split-sleeve. The stress analyses were carried out under various shapes of pipe groove configuration, materials and internal pressures with a commercial software, ANSYS workbench which uses FEM(finite element method). Results are graphically depicted with various parameters.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.87-90
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• 2003

In this paper, the electromechanical displacements of curved actuators such as THUNDER are calculated by finite element method to design the optimal configuration of curved actuators. To predict the pre-stress in the device due to the mismatch in coefficients of thermal expansion, the adhesive as well as metal and PZT ceramic is also numerically modeled by using hexahedral solid elements. Because the modeling of these thin layers causes the numbers of degree of freedom to increase, large-scale structural analyses are performed in a cluster system in this study. The curved shape and pre-stress in the actuator are obtained by the cured curvature analysis. The displacement under the piezoelectric force by an applied voltage is also calculated to compare the performance of curved actuator. The thickness of metal and adhesive, the number of metal layer are chosen as design factors.

• 경영정보학연구
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• 제3권2호
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• pp.277-288
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• 2001

Of critical importance to the success of any e-commerce site are the two factors: rapid application development and quick response time. A three-tier architecture composed of presentation layer, business layer, and data access layer emerges to allow rapid changes in user interface, business logic, and database structures. Too often, such a logical three-tier architecture is considered as requiring a three-tier physical architecture: Web server, application server, and database server running on separate computers. Contrary to the common belief, a Web stress test reveals that the three-tier logical architecture implemented on a two-tier physical platform guarantees a quicker response time due to the reduction in cross-machine communications. This would lead business firms to economize their spending on e-commerce: increasing the number of physical servers to expedite transaction is not necessarily the best solution. Before selecting a particular hardware configuration, a Web stress test needs to be conducted to compare the relative merits of alternative physical architectures. Together with capacity planning, Web stress test emerges as a powerful tool to build robust, yet economical e-commerce sites.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.930-932
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• 2002

We have carried a theoretical study on e-beam addressed liquid crystal projection display in which the liquid crystal is switched by the electric field of the charge, produced by an electron beam, on the surface of the display. We calculated the electric field produced by the surface charge, the liquid crystal director configuration and the profile of the transmitted light. We studied the factors affecting the resolution of the display. We also studied the effect of pretilt angle on the performance of the display. The e-beam addressed liquid crystal projection display potentially has the advantages of high resolution and high brightness.