• Journal of Korea Multimedia Society
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• v.18 no.7
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• pp.793-805
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• 2015

Nowadays the amount of data obtained from advanced weather radars is growing to provide higher spatio-temporal resolution. Accordingly radar data compression is important to use limited network bandwidth and storage effectively. In this paper, we proposed a hierarchical compression method for weather radar data having high spatio-temporal resolution. The method is applied to radar reflectivity and evaluated in aspects of accuracy of quantitative rainfall intensity. The technique provides three compression levels from only 1 compressed stream for three radar user groups-signal processor, quality controller, weather analyst. Experimental results show that the method has maximum 13% and minimum 33% of compression rates, and outperforms 25% higher than general compression technique such as gzip.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.113-121
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• 2002

The distribution of volume fraction, mean diameter and number density of soot particles are measured quantitatively in a co-flow ethylene diffusion flame using a simultaneous LII/LIS measurement technique. The LII/LIS system and the measured values are, respectively, calibrated and evaluated by comparing to the informations obtained from laser light. extinction/scattering experiments, LII signal shows some sensitivity to the laser light intensity when laser power density exceeds a certain value(threshold). It is also found that there is an optimal laser intensity and a delay time in order to obtain the best result using the simultaneous LII/LIS measurement technique.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.167-174
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• 1997

The penetration depth and the size distribution of the droplets of fuel sprays are important in the operation of spark-ignition MPI engines. A fluorescence/scattering image technique for droplet sizing was applied to measure th edroplet size distribution in non-evaporating gasoline sprays. The fluorescence and scattering lights were imaged simultaneously by the two-dimensional visualization system composed of a laser sheet, a doubling prism, optical filters, and a CCD camera. Quantitative droplet size distributions were extracted from evaluating the ratio of the two light densities. The mean droplet size measured by the fluorescence/scattering technique was compared with the result obtained by the enlarged photographs of droplets. The fluorescence/scattering image technique also gives the useful information of the characteristics of droplet impingement in a inclined wall.

• Culinary science and hospitality research
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• v.5 no.1
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• pp.89-101
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• 1999

This study attempts to identify the most accurate quantitative forecasting technique for measuring the future level of demand for food ＆ beverage in super deluxe hotel in Seoul, which will subsequently lead to determining the optimal level of purchasing food ＆ beverage. This study, in detail, examines the food purchasing system of H hotel, reviews three rigorous univariate time series models and identify the most accurate forecasting technique. The monthly data ranging from January 1990 to December 1997 (96 observations) were used for the empirical analysis and the 1998 data were left for the comparison with the ex post forecast results. In order to measure the accuracy, MAPE, MAD and RMSE were used as criteria. In this study, Box-Jenkins model was turned out to be the most accurate technique for forecasting hotel food ＆ beverage demand among selected models generating 3.8％ forecast error in average.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.150-159
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• 2016

This paper presents a study on the design optimization of a 5 kW plasma discharger for driving plasma reactor. The proposed study is composed of a high-frequency inverter based on the full-bridge circuit using soft switching techniques for high-frequency switching. The switching frequency in the operating region is the area of 130-200 kHz. By applying the LC resonance technique and a variable switching frequency, control technique is designed to be stable under changes in the load characteristics of the plasma reactor. This paper presents a quantitative analysis technique for design optimization. Experiments are performed according to load characteristic variations depending on the vacuum of the plasma reactor. This paper has verified the topology and design method for the 5 kW plasma discharger design.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.92-97
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• 2003

There are many and various problems due to a disease in the work. These problems result in serious social Problems such as individual and family Problem, economical loses of company. The objective of this study is to analyze the worker's consciousness and provide the precautionary measures far prevention of a disease in the work. Also, this paper presents quantitative value of priorities for prevention of a disease in the work using QFD technique. The samples for this study are chosen from the companies with less than 300 employees under charge of the Kangnung Ministry of Labor during three months (2002. 3. 2 - 2002. 5. 31).

• Transactions of Materials Processing
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• v.14 no.6 s.78
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• pp.541-546
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• 2005

Apparent mechanical properties in structural components can be different from the initially designed values due to the formation of the residual stress in metal forming and welding. Therefore, the evaluation of residual stress has great importance in the reliability diagnosis of structural components. A nondestructive continuous indentation technique has been proposed to evaluate various strength concerning mechanical properties from the analysis of load-depth curve. In this study, quantitative residual stress estimation on API X65 welded joints for natural gas pipeline was performed by analyzing the variation of indentation loading curve by residual stress through a new proposed theoretical model. The residual stress from the indentation method was compared with that from the saw-cutting method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.126-129
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• 2005

Apparent mechanical properties in structural components can be different from the initially designed values due to the formation of the residual stress in metal forming and welding. Therefore, the evaluation of residual stress has great importance in the reliability diagnosis of structural components. A nondestructive continuous indentation technique has been proposed to evaluate various strength concerning mechanical properties from the analysis of load-depth curve. In this study, quantitative residual stress estimation on API X65 welded joints for natural gas pipeline was performed by analyzing the variation of indentation loading curve by residual stress through a new proposed theoretical model. The residual stress from the indentation method was compared with that from the saw-cutting method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.870-874
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• 2004

This work presents a study on development of a practical and quantitative technique for assessment of the structural health condition by Piezoelectric impedance-based technique associated with longitudinal wave propagation method. The bolt fastening condition is adjusted by torque wrench. In order to estimate the damage condition numerically, three damage indices, impedance peak frequency shift ${\Delta}F$, peak amplitude ratio $\delta$ and quality factor ratio $\gamma$, are proposed in this paper. Furthermore, an assessment method is described for estimation of the damage by using these three damage indices.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.109-116
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• 2005

In this paper, we investigate the visual and quantitative analysis at the same time with an electronic tongue(e-tongue) system using an array of ISE(ion-selective electrode). We apply the FCM(fuzzy c-means) algorithm combined with PCA(principal component analysis), which can be reduced multi-dimensional data to third-dimensional data, to classify data patterns detected by E-Tongue system. The proposed technique can be designed to solve the cluster centers and membership grade of patterns combined with the output results obtained by PCA method. According to the proposed technique, the membership grade of unknown pattern, which does not shown previously can be determined and analyzed visually. Conclusionally, the relationship between the standard patterns and unknown pattern can be easily analyzed. Throughout the experimental trials, the proposed technique has been confirmed using developed E-Tongue system.