• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1360-1363
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• 1996

EPD(End Point Detection) is used to decide etching degree of layer which must be removed at wafer etching process in plasma etching process which is one of the most important process in semiconductor manufacturing. In this thesis, the method which detects malfunction of etching process in real-time will be discussed. Several EPD signal traces are collected in normal plasma etching condition and used as reference EPD signal traces. Critical points can be detected by applying differentiation and zero-crossing techniques to reference EPD signal. Mean and standard deviation of critical parameters which is memorized from reference EPD signal are calculated and these determine the lower and higher limit of control chart. And by applying statical control chart to EPD signals which are collected in real etching process malfunctions of process are detected in real-time. By means of applying this method to the real etching process we prove our method can accurately detect the malfunction of etching process and can compensate disadvantage of current industrial method.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2079-2081
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• 2002

R/C helicopter has been used to several fields of military affairs, investigation searching and toys because it has small size hovering and vortical take-off characteristics etc. Therefore it needs more realizable control method. The paper introduces simulation and experimental results for control of a helicopter training simulator by self tuning control method. To realize the disturbance rejection and the given reference tracking, a least common multiple polynomial between the reference and disturbance model polynomials is operated to the plant model. The effectiveness of the method is shown by simulation and experimental results for a helicopter training simulator with two degree of freedom.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1235-1241
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• 2001

An engineering estimation equation for the crack opening displacement(COD) is proposed for a complex cracked pipe, based on the reference stress approach. To define the reference stress, a simple plastic limit load analysis for the complex cracked pipe subjected to combined bending and tension is performed considering the crack closure effect in the compressive-stressed region. Comparison with ten published test data and the results from existing method shows that the present method not only reduces non-conservatism associated with the existing method, but also provides consistent and overall satisfactory results.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.10
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• pp.454-463
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• 2001

This paper presents a method for real-time estimation of TCSC reference quantity in order to enhance the power system transient stability energy margin using artificial neural network in multi-machine system. This paper has the three parts, the first part is to determine the lines to be installed by TCSC. The seconds is to estimate the energy margin using by ANN. To get the critical energy for training, we use the potential energy boundary surface(PEBS) method which is one of the transient energy function(TEF) method. And the last is to determine the TCSC reference quantity. In order to make training data for ANN in this step, we use genetic algorithm(GA). The proposed method is applied to 39-bus, 46-line. 10-machine model system to show its effectiveness.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.1
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• pp.11-19
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• 2010

Register transfer level power macromodeling is well known as a promising technique for accurate and efficient power estimation. This paper proposes effective approaches based on the tablebased method for the RTL power macro-modeling. The new parameter SD, which characterizes the distribution of switching activities for each gate in the circuit, is one of the contributions. The new parameter SD has strong correlation with power consumption. We also propose an accurate table reference method considering the circuit characteristics. The table reference method is applicable for every table-based method and outputs more accurate power value. The experimental results show that the combination of the proposed methods reduces max error 30.36% in the best case, comparing conventional methods. The RMS error is also improved 1.70% in the best case.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.5
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• pp.478-484
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• 1990

An automatic tuning method of a PID controller which is used for single input single output processes is proposed. In the proposed tuning method, the frequency response data model is adopted along with the performance index which is an integral of time weighted square error between reference model and process frequency response data model for tuning. This method is easier to retune when either the process dynamics is changed or the reference model is changed. Finally, an example is provided to show the usefulness of the method.

• Journal of radiological science and technology
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• v.41 no.1
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• pp.13-24
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• 2018

Liver size is an important component in the diagnosis and follow-up of diffuse liver disease when testing for liver disease using ultrasonography. However, difficulties lies in determining the presence of hepatomegaly and liver atrophy because the method used for measuring liver size differs from one examiner to another and there is no relevant standard based on body build. The present study aims to propose a more objective method for liver size measurement and a reference range based on body build. A total of 260 normal adults (130 males, 130 females) participated in the study. Ultrasonography was performed in all participants to measure the size of the right lobe, left lobe, quadrate lobe, and caudate lobe of liver. Based on Physique Index(PI), a value derived from multiplying weight(kg) by height($m^2$), size of physique was divided into three groups including Group I with PI<150, Group II with $150{\leq}PI{\leq}250$, and Group III with PI>250. Thus, mean liver size by PI and a reference range with 95% reliability were suggested. The superoinferior diameter of right lobe was $12.34{\pm}1.18cm$ in males and $11.07{\pm}0.93cm$ in females, and its reference range was 10.64~11.0cm for Group I, 11.78~12.12cm for Group II, and 13.02~13.84cm for Group III. The anteroposterior diameter(T) of left lobe was $5.93{\pm}1.09cm$ in males and $5.18{\pm}0.99cm$ in females, and its reference range was 4.77~5.17cm for Group I, 5.49~5.79cm for Group II, and 6.68~7.44cm for Group III. The transverse diameter was $3.51{\pm}0.60cm$ in male participants and $3.42{\pm}0.49cm$ in female participants and its reference range was 3.29~3.51cm for Group I, 3.36~3.55cm for Group II, and 3.52~4.0cm for Group III. The caudate lobe index was $11.65{\pm}2.88cm^2$ in males and $9.62{\pm}2.18cm^2$ in females and its reference range was $8.83{\sim}9.75cm^2$ for Group I, $10.62{\sim}11.47cm^2$ for Group II, and $11.89{\sim}14.26cm^2$ for Group III. As a basic measurement method of liver size, the present study suggests measuring the superoinferior diameter for right liver lobe, the anteroposterior diameter for left liver lobe, the transverse diameter for quadrate lobe, and the caudate lobe index for caudate lobe. It is expected that this method along with its relevant reference range can be used as useful indicators in determining hepatomegaly and liver atrophy upon the diagnosis and follow-up testing of diffuse liver disease.

• Spatial Information Research
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• v.8 no.1
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• pp.171-182
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• 2000

Random sampling or systematic sampling method is commonly used to assess the accuracy of classification results. In remote sensing, with these sampling method, much time and tedious works are required to acquire sufficient ground truth data. So , a more effective sampling method that can retain the characteristics of the population is required. In this study, fractal analysis is adopted as an index for reference sampling . The fractal dimensions of the whole study area and the sub-regions are calculated to choose sub-regions that have the most similar dimensionality to that of whole-area. Then the whole -area s classification accuracy is compared to those of sub-regions, respectively, and it is verified that the accuracies of selected sub regions are similar to that of full-area . Using the above procedure, a new kind of reference sampling method is proposed. The result shows that it is possible to reduced sampling area and sample size keeping up the same results as existing methods in accuracy tests. Thus, the proposed method is proved cost-effective for reference data sampling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.165-170
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• 2015

The topic of this paper is the advanced absolute altitude determination for 3-D positioning using barometric altimeter and the reference station. Barometric altimeter does not provide absolute altitude because atmosphere pressure always varies over the time and geographical location. Also, since Global Navigation Satellites system such as GPS, GLONASS has geometric error, the altitude information is not available. It is the reason why we suggested the new method to improve the altitude accuracy. This paper shows 3-D positioning algorithm using absolute altitude determination method and evaluates the algorithm by real field tests. We used an accurate altitude from RTK system in Seoul as a reference data and acquired the differential value of pressure data between a reference station and a mobile station equipped in low cost barometric altimeter. In addition, the performance and advantage of the proposed method was evaluated by 3-D experiment analysis of PNS and CNS. We expect that the proposed method can expand 2-D positioning system 3-D position determination system simply and this 3-D position determination technique can be very useful for the workers in the field of fire-fighting and construction.

• Geophysics and Geophysical Exploration
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• v.22 no.2
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• pp.49-55
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• 2019

In this study, we presented a reference-shot subset method for stable convergence of full waveform inversion using a cyclic-shot subsampling technique. Full waveform inversion needs repetitive modeling of wave propagation and thus its calculation time increases as the number of sources increases. In order to reduce the computation time, we can use a cyclic-shot subsampling method; however, it makes the cost function oscillate in the early stage of the inversion and causes a problem in applying the convergence criteria. We introduced a method in which the cost function is calculated using a fixed reference-shot subset while updating the model parameters using the cyclic-shot subsampling method. Through the examples of full waveform inversion using the Marmousi velocity model, we confirmed that the convergence of cost function becomes stable even under the cyclic-shot subsampling method if using a reference-shot subset.