• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.985-987
• /
• 2011

This paper includes a development of a starting time prediction model for a derivative engine. For this derivative engine design, a new map expansion method, Modified Pump Scaling Law(MPS), has been applied and expand the maps to sub-idle range. From loss characteristics of the reference engine, loss models for the derivative engine have been developed considering different pressure, temperature, and engine configurations. Starting time predictions of the derivative engine shows preferable results comparing test results.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.1
• /
• pp.36-43
• /
• 1999

This paper proposes a new hybrid genetic algorithm for auto-tuning fuzzy controllers improving the performance. In general, fuzzy controllers use pre-determined moderate membership functions, fuzzy rules, and scaling factors, by trial and error. The presented algorithm estimates automatically the optimal values of membership functions, fuzzy rules, and scaling factors for fuzzy controllers, using a hybrid genetic algorithm. The object of the proposed algorithm is to promote search efficiency by the hybrid optimization technique. The proposed hybrid genetic algorithm is based on both the standard genetic algorithm and a modified gradient method. If a maximum point is not be changed around an optimal value at the end of performance during given generation, the hybrid genetic algorithm searches for an optimal value using the the initial value which has maximum point by converting the genetic algorithms into the MGM(Modified Gradient Method) algorithms that reduced the number of variables. Using this algorithm is not only that the computing time is faster than genetic algorithm as reducing the number of variables, but also that can overcome the disadvantage of genetic algoritms. Simulation results verify the validity of the presented method.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.9
• /
• pp.74-81
• /
• 2002

Recently tube hydroforming has been widely applied to the automotive industries due to its several advantages over conventional methods. In this paper, attention is paid to comparison of an implicit and an explicit finite element method widely used for numerical simulation of a hydroforming process. For an explicit FEM, a huge amount of computational time is required because of the very small time increment to solve a quasi-static problem. Hence, when an explicit FEM is used fDr a hydroforming process, it is general to convert the real problem to a virtual problem with a different processing time and mass density by appropriate scaling factor. However it is difficult to figure out how large the scaling should be adopted enough to ignore the dynamic effects and maintain the desired accuracy. In this paper, the comparison of the results obtained from both methods focus on the accuracy of the predicted geometrical shape and the stress with various scaling factors which are applied to analyze hydroforming process of an automobile lower arm.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.5
• /
• pp.887-892
• /
• 2003

In this paper, we propose a simple scaling algorithm for CDMA mobile communications where a voice traffic signals are transmitted by individual one of several data rates at every frames. The traditional method is based on using look-up table called SMT(symbol metric table), but the proposed algorithm is real-time direct scaling method through simple bit manipulations without lookup table. The bit error rate performance is calculated by computer simulation over AWGN and Rayleigh fading channels. From the results, it is shown that the proposed algorithm outperforms the traditional SMT method on Rayleigh channel by 0.3∼0.8dB, while achieving the less H/W complexity.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.1
• /
• pp.213-224
• /
• 2010

In this paper, we propose an algorithm both geometric correction using a grid point image and radiometric adaptive projection that dependent upon the luminance of the input image and that of the background. This method projects and captures the grid point image then calculates the geometrically corrected position by difference between the two images. Next, to compensate color, a corrected image is calculated by the ratio divided luminance of an input image by luminance of arbitrary surface. In addition, we found the scaling factor which controls the contrast to avoid clipping error. At this time, the scaling factor is dependent on mean image lightness when background is determined. Experimental results show that the proposed method achieves good performance and is able to reduce the perceived color clipping and artifacts, better approximating the projection on a white screen.

• Proceedings of the KIEE Conference
• /
• 1992.07a
• /
• pp.261-264
• /
• 1992

In designing the fuzzy rule-based system, it has effected by the four significant factors such as the choice of membership function, scaling factor, the numbers of fuzzy control rule, the method of defuzzification. In this paper we design the fuzzy rule based system and evaluate by three factors, as followes reaching time, overshoot, and amplitude. And then we wiII show that the significant factors are the choice of scaling factor and the numbers of fuzzy control rule, and the system performance can be improved by the proper selection of the scaling factors.

• The KIPS Transactions:PartD
• /
• v.10D no.6
• /
• pp.935-948
• /
• 2003

An online scaling method adds new nodes to the shared-nothing database cluster and makes tables be reorganized while the system is running. The objective is to share the workload with many nodes and increase the capacity of cluster systems. The existing online scaling method, however, has two problems. One is the degradation of response time and transactions throughput due to the additional overheads of data transfer and replica's condidtency. The other is and inefficient recovery mechanism in which the overall scaling transaction is aborted by a fault. These problems deteriorate the availability of shared-nothing database cluster. To avoid the additional overheads throughout the scaling period, our scalingmethod consists of twophases : a parallel data transfer phase and a combination phase. The parallel data transferred datausing reduces the size of data transfer by dividing the data into the number of replicas. The combination phase combines the transferred datausing resources of spare nodes. Also, our method reduces the possibility of failure throughout the scaling period and improves the availability of the database cluster.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.3
• /
• pp.559-566
• /
• 2012

In this paper, we propose a fast fractal image coding algorithm to shorten long time to take on fractal image encoding. For its performance evaluation, the algorithm compares with other traditional fractal coding methods. In the traditional fractal image coding methods, an original image is contracted by a factor in order to make the corresponding image to be compared with. Then, the whole area of the contracted image is searched in order to find the fixed point of contractive transformation of the original image corresponding to the contracted image. It needs a lot of searching time on encoding. However, the proposed algorithm considerably reduces encoding time by using scaling method and limited search area method. On comparison of the proposed algorithm with Jacquin's method, the proposed algorithm is dozens of times as fast as that of Jacquin's method on encoding time with a little degradation of the decoded image quality and a little increase of the compression rate. Therefore, it is found that the proposed algorithm largely improves the performance in the aspect of encoding time when compared with other fractal image coding methods.

• Korean Journal of Health Education and Promotion
• /
• v.22 no.1
• /
• pp.1-16
• /
• 2005

The study was performed to examine the scaling behavior about dental health. The subjects of this study were 700 workers selected in Daegu. This survey was carried out during 2003. 7. 15 - 2003. 7. 31. The results of this study can be summarized as follows. 1. Distribution of respondent's class was male of $53.5\%, female of $46.2\%, and 30's age of $36.2\%, 20's age of $28.2\%. Concerning about dental health was appeared that female was higher rate than male. also, difference was related in their age, working department and residence. 2. In case of no experience to scaling for past 3 years was appeared that male of $67.6\% was higher rate than female of $56.8\%. The frequency of treat scaling was appeared that $46.2\% of the subjects was treated scaling per year. 3. The root cause of no treatment by regular was appeared that 'high expensive' was most high with $38.0\% and 2nd, 'didn't felt importance' was $24.2\%, 3rd 'lack of spare time' was $20.7\%, the last ranking 'only be frightened' was $14.3\%. 4. Method of learning knowledge about scaling was appeared that male and female were similar with their method of it. knowledge level of scaling was learned by internet were higher in worker of 20's age than any other age. also, other difference was related in school career and residence. Opinion about necessity of scaling answer which need or surely need were similar to male of $67.1\% and female of $72.6\%. 5. As for knowledge of scaling was appeared that male of $94.3\% and female of $87.1\% had corrective knowledge. The right answer was significantly different by ages, school career, working department and residence.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.12
• /
• pp.1089-1096
• /
• 2015

A marine helicopter should remain sufficiently upright to permit safe evacuation of all personnel with a flotation system. And the rule requires that after ditching in water, the adequate flotation time will allow the occupants to leave the rotorcraft. To this end, stability test of the emergency flotation system for Korean marine helicopter was performed by using "Froude scaling method" in water tank. Test configuration and conditions were determined in consideration of the helicopter loading condition and related specifications. Test results meet the stability requirements at sea state code 4 and sea state code 2 with puncture conditions.