• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.130-135
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• 2014

In this paper, a new estimation method is proposed to calculate steering rack axial force using a 3 dimensional tire mesh model when a car is standing on the road. This model is established by considering changes of camber angle and contact patch between the tires and the ground according to steering angle. The steering rack bar axial force is estimated based on the static equilibrium equations of forces and moments. A tire friction force is supposed to act on the center point of the contact patch, and the proportional coefficient of friction depending on contact patch is suggested. Using the proposed estimation method, rack axial force sensitivity analysis is evaluated according to changes of suspension geometry. Then optimal motor power of Motor Driven Power Steering(MDPS) is evaluated using suggested rack forces.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.2
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• pp.66-72
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• 1992

A computational method of the Michell integral for water of finite depth is developed and the method makes use of the expansion of the hull form by the Legendre polynomial in both the longitudinal and the vertical directions. The wave resistance coefficient is given as a quadruple summation of the product of the shape factor and the hydrodynamic factor. The shape factor depends only upon the geometry of the hull form, and the hydrodynamic factor upon the depth-based Froude number and the ratios of the water depth and the draft to the ship length. Example calculations are done for the Wigley parabolic hull and the Series 60 $C_B$ 0.6, and the comparison of our results with the existing experimental data is shown.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.5
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• pp.396-409
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• 2019

In this paper, a comparative study on the radiation techniques for the motion analysis of the three dimensional floating structure with the forward speed was carried out. The Sommerfeld radiation condition, the damping technique, and the point shift technique were used for the comparative study. Radiated wave patterns and hydrodynamic coefficients of the heave motion of floating structure with the forward speed were compared and analyzed. The characteristics and limitations of each radiation technique were analyzed through the calculation results. To overcome the limitations of conventional radiation techniques, the hybrid radiation technique combining the Sommerfeld radiation condition with the damping technique was proposed. It is confirmed that the proposed method, the Hybrid radiation technique, improves the limitation of the speed range and the dissipation of the wave of the conventional radiation technique. The motion analysis code of the three dimensional floating structure with the forward speed based on the Rankine source method with hybrid radiation technique was developed. In order to validate the developed code, hydrodynamic analyses were carried and compared with published experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1423-1431
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• 2001

Based on the exponential intervening variable, a new two-point approximation method is presented. This introduces the shifting level into each exponential intervening variable to avoid the lack of def inition of the conventional exponential intervening variables due to zero-or negative-valued design variables. Then a new quadratic approximation whose Hessian matrix has only diagonal elements of different values is proposed in terms of these intervening variables. These diagonal elements are determined in a closed form that corrects the typical error in the approximate gradient of the TANA series due to the lack of definition of exponential type intervening variables and their incomplete second-order terms. Also, a correction coefficient is multiplied to the pre-determined quadratic term to match the value of approximate function with that of the previous point. Finally, in order to show the numerical performance of the proposed method, a sequential approximate optimizer is developed and applied to solve six typical design problems. These optimization results are compared with those of TANA-3. These comparisons show that the proposed method gives more efficient and reliable results than TANA-3.

• YAKHAK HOEJI
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• v.28 no.2
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• pp.61-67
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• 1984

A method is described for the spectrophotometric determination of platinum (IV) with 2-oximino-1-indanone based on solvent extraction of Pt:2-oximino-1-indanone complex. The 2-oximino-1-indanone reacted with Pt(IV) to form a dark-orange complex which shows a characterisic maximum absorption at 342nm. The optimum PH for the platinum extraction lies between 5.4~8.0. Beer's law obeys up to 0.98-16.3ppm of platinum (IV) and the molar absorption coefficient is $1.06{\times}10^{-4}L.mol^{-1}.cm^{-1}$. The relative standard deviation of the method was $\times2.1%$. The composition of the complex is estimated to be Pt : In= 1 : 1, by the mole ratio method and ion exchange resin experiment. The optimum condition for the determination of platinum has been studied in detail. The 2-oximin-1-indanone is found to be a selectivereagent for the determination of platinum, since the synthesixed 2-oximino-1-indanone did not react with other metals such as cobalt, cadmium, copper, manganese nickel, iron, lead and zinc, to form the complex. In this studies, we have also clarified Sindhwani and Singh's spectrophotometric determination data of various metals with acenaphthenequinone monooxime (Talanta 20,248, 1973), whose results were not correct.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.5 s.305
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• pp.165-172
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• 2005

In speech recognition under a noisy environment, it is necessary to construct a system which reduces the noise and enhances the speech. Then it is effective to imitate the human auditory system which has an excellent analytical spectrum mechanism for speech enhancement. Accordingly, this paper proposes an adaptive method using the auditory mechanism which is called lateral inhibition. This method first estimates the noise intensity by neural network, then adaptively adjusts both the coefficients of the lateral inhibition and the adjusting coefficient of amplitude component according to the noise intensity for each input frame. It is confirmed that the proposed method is effective for speech degraded by white noise, colored noise, and road noise based on the spectral distortion measurement.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.545-548
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• 2008

As the corrosion of reinforcing bar in concrete structures exposed to chloride attack is one of main factors to determine the remaining service life, marine concrete structures have to be designed to protect the chloride penetration. Among the durability design methods such as deterministic method and probabilistic method, design method based on the probabilistic theory has been widely studied. However, the most essential material, data of the material properties related to chloride diffusion, are still insufficient. In this paper, the probabilistic distribution of chloride diffusion coefficients and aging coefficients are derived by the experiment and analysis for the chloride coefficients of concrete containing pozzolans, which are generally used in marine structures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1532-1536
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• 2004

So far, the quantified elasticity data of textile fabrics has not been present because the measurement method depends on the knowledge of measurement operators. In this paper, the special manufactured measurement equipment using road cell is presented to measure the elasticity coefficient of textile fabrics in real time. The measurement method is based on the voltage differency among textile fabrics. The textiles with strong elasticity are high voltage produced from road cell. The others are low. The presented method can be applied to visualize the textile, sew the cloth, control quality of textile fabrics. Also, these measurement datum are used to B2B electronic trading system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.13-13
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• 1998

A simple model of the tip leakage flow models of the rotor downstream flow is developed, based on Lakshminarayana's theoretical concept on the tip clearance flow and the experimental data published in open literature. And new spanwise distribution models of deviation angle and pressure loss coefficient due to the tip leakage flow are formulated for use in association with the streamline curvature method as a through flow analysis. Combining these new models and previous deviation and loss models due to secondary flow, a robust streamline curvature method is established for flow analysis of single-stage, subsonic axial turbines with wide ranges of turning angle, aspect ratio and blading type. At the exit from rotor rows, the flow variables are mixed radially according to a spanwise transport equation. The proposed streamline curvature method is tested against a forced vortex type turbine as well as a free vortex type one. The results show that the spanwise variations of flow angle, axial velocity and loss coefficients at rotor exit are predicted with good accuracy, being comparable to a steady three-dimensional Navier-Stokes analysis. This simple and fast flow analysis is found to be very useful for the turbine design at the initial design phase.

• Structural Engineering and Mechanics
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• v.39 no.1
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• pp.147-168
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• 2011

To ensure safety and long term performance, structural control has rapidly matured over the past decade into a viable means of limiting structural responses to strong winds and earthquakes. Nonlinear response history analysis requires rigorous procedure to compute seismic demands. Therefore the simplified nonlinear analysis procedures are useful to determine performance of the structure. In this investigation, application of improved capacity demand diagram method in the control of structural system is presented for the first time. Developed pole assignment method (DPAM) in structural systems control is introduced. Genetic algorithm (GA) is employed as an optimization tool for minimizing a target function that defines values of coefficient matrices providing the placement of actuators and optimal control forces. The ground acceleration is modified under induced control forces. Due to this, performance of structure based on improved nonlinear demand diagram is selected to threshold of nonlinear behavior of structure. With small energy consumption characteristics, semi-active devices are especially attractive solutions for limiting earthquake effects. To illustrate the efficiency of DPAM, a 30-story steel moment frame structure employing the semi-active control devices is applied. In comparison to the widely used linear quadratic regulation (LQR), the DPAM controller was shown to be just as effective and better in the reduction of structural responses during large earthquakes.