• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.147-155
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• 2005

The purpose of this paper is to develop a method for estimation of reliable path-travel time using data obtained from the toll collection system on freeways. The toll collection system records departure and arrival time stamps as well as the identification numbers of arrival and destination tollgates for all the individual vehicles traveling between tollgates on freeways. Two major issues reduce accuracy when estimating path-travel time between an origin and destination tollgate using transaction data collected by the toll collection system. First, travel time calculated by subtracting departure time from arrival time does not explain path-travel time from origin tollgate to destination tollgate when a variety of available paths exist between tollgates. Second, travel time may include extra time spent in service and/or rest areas. Moreover. ramp driving time is included because tollgates are installed before on-ramps and after off-ramps. This paper describes an algorithm that searches for arrival time when departure time is given between tollgates by a Progressive Iterative Forward and Backward (PIFAB) search method. The algorithm eventually produces actual path-travel times that exclude any time spent in service and/or rest areas as well as ramp driving time based on a link-based procedure.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.468-472
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• 2004

In this paper a VLSI design for the automatic magnetizing system has been presented. This is the design of a peripheral controller, which magnetizes CRTs and computers monitors and controls the automatic inspection system. We implemented a programmable peripheral interface(PPI) circuit of the control and protocol module for the magnetizer controller by using a O.8um CMOS SOG(Sea of Gate) technology of ETRI. Most of the PPI functions has been confirmed. In the conventional method, the propagation/ramp delay model was used to predict the delay of cells, but used to model on only a single cell. Later, a modified "apos;Linear delay predict model"apos; was suggested in the LODECAP(LOgic Design Capture) by adding some factors to the prior model. But this has not a full model on the delay chain. In this paper a new "apos;delay predict equationapos;" for the design of the timing control block in PPI system has been suggested. We have described the detail method on a design of delay chain block according to the extracted equation and applied this method to the timing control block design.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.68-74
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• 2005

Optimal shape of a typical ramjet intake is examined numerically to maximize the total pressure recovery. A response surface method is introduced to approximately predict its performance with respect to the design parameters over the each design domain. The first deflection angle of ramp, the area of inlet throat, and the diffuser angle are chosen as a design parameter. ANOVA is used to verify the trustability of the achieved response surface. The total pressure recovery of the optimum model, compared to that of the base model, is increased by 36%. The loss of viscosity through the diffuser is estimated less than 5%.

• IE interfaces
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• v.21 no.3
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• pp.294-301
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• 2008

Agile and flexible manufacturing systems make it mandatory that a control program should have features such as agility, flexibility, and reusability in order to run manufacturing unit smoothly. PLCs are the most frequently used control program in manufacturing systems. PLC programs are mostly programmed by subcontraction, which makes correction of code very difficult. As a result, it may cause delay during down time and ramp up time which leads to big loss of revenue and goodwill. To prevent delay during the times, this paper proposes systematic process analysis and application method for programmable logic controller like LLD (Ladder Logic Diagram). The proposed method uses modified human-error investing techniques for documentation and transforming technique to program LLD from the documentation. Furthermore, this paper demonstrates an example of piston mechanism to explain the proposed method.

• Transactions of the Society of Information Storage Systems
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• v.2 no.3
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• pp.169-177
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• 2006

In this study, we present the optimization of a head slider using kriging method in order to reduce lift-off force during unloading process with satisfying reliable flying attitude in steady state. To perform an optimization process efficiently, a simplified lift-off force model, which is a function of air bearing suction force and flying attitudes, is created by kriging method. The EMDIOS, which is the process integration and design optimization software developed by iDOT, is used to automatically wrap the analysis with the optimization and efficiently implements the repetitive works between analyzer and optimizer. An optimization problem is formulated to reduce the lift-off force during unloading process while satisfying the flying attitude in reliable range over the entire recording band and reducing the probability of contact between slider and disk. The simulation result shows that the amplitude of lift-off force of optimized L/UL slider is reduced about 62%, compared with that of initial slider model. It is demonstrated by the dynamics L/UL simulation that the optimum slider incorporated with the suspension is not only smoothly loaded onto disk but also properly unloaded onto the ramp.

• Structural Engineering and Mechanics
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• v.45 no.6
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• pp.759-777
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• 2013

In this paper, a topology optimization method based on the element independent nodal density (EIND) is developed for continuum solids with multiple load cases and multiple constraints. The optimization problem is formulated ad minimizing the volume subject to displacement constraints. Nodal densities of the finite element mesh are used a the design variable. The nodal densities are interpolated into any point in the design domain by the Shepard interpolation scheme and the Heaviside function. Without using additional constraints (such ad the filtering technique), mesh-independent, checkerboard-free, distinct optimal topology can be obtained. Adopting the rational approximation for material properties (RAMP), the topology optimization procedure is implemented using a solid isotropic material with penalization (SIMP) method and a dual programming optimization algorithm. The computational efficiency is greatly improved by multithread parallel computing with OpenMP to run parallel programs for the shared-memory model of parallel computation. Finally, several examples are presented to demonstrate the effectiveness of the developed techniques.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.119-131
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• 2019

Among the themes for CSR(Corporate Social Responsibility), consumer issues include protecting the health and safety of consumers who purchase and use the products. In particular, ensuring product safety is a major theme of consumer issues for corporate social responsibility. Currently, the government implements the Electrical Appliances and Consumer Products Safety Control Act for product safety management and selects products that may harmful to consumers as safety control items, and manages the products by designating them as 4 types of safety certification, safety confirmation, supplier conformity verification, and safety standard compliance. In this paper, we propose management plans for the establishment of a more reasonable classification type of safety management target for 48 items of consumer products to be controlled by the act, and confirm the validity of the plan. First, we perform cluster analysis using data for CISS (Consumer Injury Surveillance System) to derive a new classification type of the safety management target. Next, we compare the results of the cluster analysis with the classification type of the act and the existing scenario classification method RAS (Risk Assessment by Scenario) and the causal network method RAMP (Risk Assessment Method based on Probability). Based on these results, we propose two new plans of safety management target classification and verify its validity.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1532-1534
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• 1999

Electrical treeing phenomenon, regarded as pre-breakdown which accelerates aging process leading an insulation to the complete breakdown, is with no doubt extremely fatal to the performance of the insulation. Investigated in this paper is electrical treeing representing local dielectric failure according to flow pattern, the flow history of liquid polyethylene formed during the extrusion process. Experiments of electrical tree initiation by means of ramp tests were conducted using newly developed electrode system with point-to-point structure. Constant voltage tests were also carried out with the electrode system to estimate the life time of the insulation. Results were analyzed using statistical method such as Weibull distribution.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.1
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• pp.99-104
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• 2013

Configuration design, analysis, and wind tunnel test of a vane-type multi-function air data probe (MFP) was described. First, numerical analysis was conducted for the initial configuration of the MFP in order to investigate aerodynamic characteristics. Then, the design was modified to improve static and dynamic stability for better response characteristics. The modified configuration design was verified through wind tunnel tests. The test results are also used to verify the accuracy of the analytical method. The analytically estimated aerodynamic damping provided by the Navier-Stokes equation solver correlated well with the wind tunnel test results. According to the calculation, the damping coefficient estimated from ramp motion analysis yielded a better correlation with the wind tunnel test than pitch oscillation analysis.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.370-373
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• 1991

This paper considers the linear multivariable model following servo system synthesis method in which linear optimal regulator problem is used to design controllers that make the response of the plant should be kept close to a specified ideal response of the model. The characteristics of this system is that the constructed system is robust in the presence of the constant disturbances or the parameter perturbations of the plant. Especially, the steady state offset is excluded for the ramp response of the model by direct feedforward compensator from the reference input.