• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.119-126
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• 2000

In this paper. a simple high-speed crash test rig for members of vehicle was developed for the improvement of crashworthiness of vehicle's side rail. The cart hanging the specimen is accelerated up to 35 mph by the force of freely dropping weight and 1:3 accelerating pulleys. The cart with shock absorbers travels on the rail roads, so it does not transfer any additional vibration to the specimen. To measure the test results, two types of accelerator are considered. the one is a strain gage type and the other is a piezo type. The test rig is rated good to test the specimen like a side rail of vehicle as developing the vehicle's structures in the early design stage.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.203-206
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• 1998

In reinforced concrete carbonation of concrete leads to depassivation of the reinforcement, and hence to initiation of corrosion. As a result of carbonation accelerating experiment with using effect of wet-dry cycle and 15% concentration of CO ₂, the carbonation rate shows very distinct difference according to W/C ratio. OPC-40 estimated no carbonation depth, whereas OPC-60 estimated rapidly the carbonation rate. The comparative analysis of the carbonation rate accelerating depends on different kinds of cement shows fastest FAC-20. Also, highly W/C ratio's concrete shows low half-cell potential value and fast corrosion rate. During period for 14 weeks. corrosion rate was not severe. So, it can be concluded that only carbonation attack on concrete doesn't severly deteriorated except very poor qualitified concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1989.10a
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• pp.9-13
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• 1989

The purpose of this paper is to propose a method predetermining the 28-days strength of concrete. In this paper, it was predicted by regression analysis of the relation between 7-days and 28-days strength of fresh concrete and the strength of concrete early cured at $70^{\circ}C$ for rour hours after wet screening and addition of accelerating agent. It is concluded that the formula predeterming the 28-days strength of concrete using 25M/M rubbles from Sam-Cheok and sands from Yon-Gok, by the strength of concrete early cured for 4 hours is Y=-11.45 + 3.686X, where the coefficient of determination of regression-expression is r2=0.938, S=17.94(kg/$\textrm{cm}^2$).

• Journal of Environmental Science International
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• v.16 no.4
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• pp.495-503
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• 2007

In this study, we took the geometrical character of the river channel junction and hydrologic conditions as independent variables, and hydraulic behavior characteristics as an independent variable. The result, after multiple analysis was carried out, proved that, except for the generating area of the accelerating zone of velocity the accelerating zone and both the main channel and the tributary zone of stagnation the stagnation zone, there was correlation of over 90%. Also, derived presumed expression of the hydraulic characteristics of the junction was applied to the real natural channel - the river channel of the Guem-ho main channel(the A-yang bridge to the Guem-ho bridge). As the result, it proved that it represented hydraulic characteristics relatively well.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.1
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• pp.21-28
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• 2005

This paper proposes a new method for accelerating the search speed of genetic algorithms by taking derivative evaluation and conditional random selection into account in their evolution process. Derivative evaluation makes genetic algorithms focus on the individuals whose fitness is rapidly increased. This accelerates the search speed of genetic algorithms by enhancing exploitation like steepest descent methods but also increases the possibility of a premature convergence that means most individuals after a few generations approach to local optima. On the other hand, derivative evaluation under a premature convergence helps genetic algorithms escape the local optima by enhancing exploration. If GAs fall into a premature convergence, random selection is used in order to help escaping local optimum, but its effects are not large. We experimented our method with one combinatorial problem and five complex function optimization problems. Experimental results showed that our method was superior to the simple genetic algorithm especially when the search space is large.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.3
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• pp.21-27
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• 2002

In this paper, a simple test rig of high-speed crash for the front members of vehicles was developed for the improvement of crashworthiness of vehicle's side rail. The cart hanging the specimen is accelerated up to 35 mph by the traction wire and by the force of freely dropping weight and 1:3 accelerating pulleys. The cart with shock absorbers travels on the rail roads, so it does not transfer any additional vibration to the specimen. In order to measure the energy absorbed by the specimen when it collapse to the wall and during it deform, the two strain gage type load cells are used at the wall place. The test rig rated good to test the specimen like a side rail of vehicle as developing the vehicle's structures in the early design stage.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.1
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• pp.37-41
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• 2014

FFT (Fast Fourier Transform) has been widely used in various fields such as image processing, voice processing, physics, astronomy, applied mathematics and so forth. Much research has been conducted due to the importance of the FFT and recently new FFT algorithms using a GPU (Graphics Processing Unit) have been developed for the purpose of much faster processing. In this paper, the new optimal FFT algorithm using the Pease FFT algorithm has been proposed reflecting the hardware configuration of a GPGPU (General Purpose computing of GPU). According to the experiments, the proposed algorithm outperformed by between 3% to 43% compared to the CUFFT algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.51-65
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• 1991

This paper describes computer-integrated manufacturing (CIM) systems as strategic information systems for business which play an important role in accelerating the speed of business, and develops a measure showing a degree of business tendency to be CIM which enables the business to check on its present status as far as CIM is concerned. It is well known that the productivity of knowledge workers is lower than that of other workers. Nowadays, a great deal of effort goes into the productivity improvement of knowledge workers. In this respect, this paper also develops a quantitative model for the productivity of knowledge workers. Finally, this paper deals with following four steps which our small business should follow through its process of CIM: [Step 1] Using expert knowledge; [Step 2] Invention of technological information; [Step 3] Feedback of factory information to the management; and, [Step 4] Accelerating the speed of business.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.470-475
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• 1998

A robust control technique is presented for a high performance control of a permanent-magnet(PM) synchronous motor. In order to deal with the internal and external disturbances of a PM synchronous motor drive system, a new feedback control structure is proposed. Since the dynamic behavior of the PM synchronous motor drive system is mainly concerned with the difference between the electro-magnetically developed torque and the load torque which generally referred to as an accelerating torque, the estimation and control techniques of this torque are introduced. The simulations and experiments are carried out for the DSP-based PM synchronous motor drive system and the results well demonstrate the effectiveness of the proposed control technique.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.409-420
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• 2015

Purpose: This study is to estimate the life of elevator wire rope by using the accelerated degradation test with two accelerating variables of applied load and corrosion. Methods: Linear regression method is used to find the pseudo life of elevator wire rope at each combination of accelerating variables and the median life of elevator wire rope at use condition is estimated under the assumption that the life of elevator wire rope follows lognormal distribution. Results: The particular case study demonstrated that the results of the elevator wire life estimation by using the proposed method can provide the better solutions than existing methods. Conclusion: It can be economical to use accelerated degradation model for estimating the life of elevator wire rope.