• Journal of the Korean Data and Information Science Society
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• v.11 no.1
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• pp.91-101
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• 2000

We propose a new method for estimating the mean of a population which has a linear trend. The suggested estimator is based on the centered balanced systematic sampling method and the concept of interpolation and extrapolation. The efficiency of the proposed method is compared with that of existing methods.

• Journal of Korea Water Resources Association
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• v.39 no.6 s.167
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• pp.495-502
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• 2006

The importance of the bandwidth selection has been more emphasized than the kernel function selection for nonparametric frequency analysis since the interpolation is more reliable than the extrapolation method. However, when the extrapolation method is being applied(i.e. recurrence interval more than the length of data or extreme probabilities such as $200{\sim}500$ years), the selection of the kernel function is as important as the selection of the bandwidth. So far, the existing kernel functions have difficulties for extreme value estimations because the values extrapolated by kernel functions are either too small or too big. This paper suggests a Modified Cauchy kernel function that is suitable for both interpolation and extrapolation as an improvement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.3
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• pp.146-151
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• 2018

In this study, we compared the threshold-voltage extraction methods of accumulation-type JLDG (junctionless double-gate) MOSFETs (metal-oxide semiconductor field-effect transistors). Threshold voltage is the most basic element of transistor design; therefore, accurate threshold-voltage extraction is the most important factor in integrated-circuit design. For this purpose, analytical potential distributions were obtained and diffusion-drift current equations for these potential distributions were used. There are the ${\phi}_{min}$ method, based on the physical concept; the linear extrapolation method; and the second and third derivative method from the $I_d-V_g$ relation. We observed that the threshold-voltages extracted using the maximum value of TD (third derivatives) and the ${\phi}_{min}$ method were the most reasonable in JLDG MOSFETs. In the case of 20 nm channel length or more, similar results were obtained for other methods, except for the linear extrapolation method. However, when the channel length is below 20 nm, only the ${\phi}_{min}$ method and the TD method reflected the short-channel effect.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.1
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• pp.25-31
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• 1984

An algorithm on time limited signal extrapolation technique is presented where the total extrapolation process of iteration method is achieved by a single matrix operation. The proposed technique and its implementation has many advantages over iteration method in terms of computational saving and accuracy of the results. As an examples in this paper, appling the proposed technique to ultrasonic diagnosis-device, we prove the excellence of the proposed technique.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.494-501
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• 2009

Probabilistic Ecological risk assessment (PERA) is extensive approach to qualify and quantify risk on the multi species based on species sensitivity distribution (SSD). As a while, deterministic ecological risk assessment (DERA) considers the comparison of predicted no-effect concentration (PNEC) and predicted exposure concentration (PEC). DERA is used to determine if there is potential risk or no risk, and it doesn't consider the nature variability and the species sensitivity. But PERA can be more realistic and reasonable approach to estimate likelihood or risk. In this study, we compared PERA used in developed countries, and proposed PERA applicable for the Korean water environment. Taxonomic groups were classified as "class" level including Actinopterygill, Branchiopoda, Chlorophyceae, Maxillapoda, Insects, Bivalvia, Gastropoda, Secernentea, Polychaeta, Monocotyldoneae, and Chanophyceae in this study. Statistical extrapolation method (SEM), statistical extrapolation method $_{acutechronicratio}$ ($SEM_{ACR}$) and assessment factor method (AFM) were used to calculate the ecological protective concentration based on qualitative and quantitative levels of taxonomic toxicity data. This study would be useful to establish the PERA for the protection of aquatic ecosystem in Korea.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.1014-1017
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• 2012

In this paper, we introduce a method which enhances the azimuth resolution to obtain the high-resolution SAR image. We used ${\omega}-k$ algorithm to obtain the SAR image and extrapolation using auto-regressive(AR) method to enhance the azimuth resolution in the 2-D frequency domain. The AR method is a linear prediction model-based extrapolation technique. In the result, we showed the performance comparison with respect to the target range and the prediction order of Burg algorithm which is one of AR method.

• Journal of Platform Technology
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• v.10 no.3
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• pp.44-50
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• 2022

Research on facial age estimation is being actively conducted because it is used in various application fields. Facial images taken in various environments often have occlusions, and there is a problem in that performance of age estimation is degraded. Therefore, we propose age estimation method by creating an occluded part using image extrapolation technology to improve the age estimation performance of an occluded face image. In order to confirm the effect of occlusion in the image on the age estimation performance, an image with occlusion is generated using a mask image. The occluded part of facial image is restored using SpiralNet, which is one of the image extrapolation techniques, and it is a method to create an occluded part while crossing the edge of an image. Experimental results show that age estimation performance of occluded facial image is significantly degraded. It was confirmed that the age estimation performance is improved when using a face image with reconstructed occlusions using SpiralNet by experiments.

• Steel and Composite Structures
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• v.22 no.1
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• pp.203-216
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• 2016

To study the stress concentration factors (SCFs) of concrete-filled tubular Y-joints subject to in-plane bending, experiments were used to investigate the hot spot stress distribution along the intersection between chord and brace. Three concrete-filled tubular chords forming Y-joints were tested with different reinforcing components, including doubler-plate, sleeve, and haunch-plate reinforcement. In addition, an unreinforced joint was also tested for comparison. Test results indicate that the three different forms of reinforcement effectively reduce the peak SCFs compared with the unreinforced joint. The current research suggests that the linear extrapolation method can be used for chords, whereas the quadratic extrapolation method must be used for braces. The SCF is effectively reduced and more evenly distributed when the value of the axial compression ratio in the chord is increased. Furthermore, the SCFs obtained from the test results were compared to predictions from some well-established SCF equations. Generally, the predictions from those equations are very consistent for braces, but very conservative for concrete-filled chords.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.7-8
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• 2017

Corrosion of reinforced concrete embedded in concrete is a deterioration phenomenon due to intrusion of embodied or Airborne chloride ions. Corrosion of a embedded steel increases the volume of the rebar and causes damage to the structure such as cracking and peeling of the concrete. This causes penetration of various corrosive factors and accelerates the corrosion of reinforcing bars, which has a serious effect on the durability of the structure. Researches on the corrosion phenomenon of these rebars by electrochemical methods have been carried out for a long time, but it is a lack of research in Korea. Therefore, in this study, one of electrochemical experimental methods, Tafel extrapolation method, was used to evaluate the performance of reinforcing bars according to the amount of NaCl and LiNO₂ added to concrete.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.1
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• pp.16-21
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• 2015

Most video services are transmitted in wireless networks. In a network environment, a packet of video is likely to be lost during transmission. For this reason, numerous error concealment (EC) algorithms have been proposed to combat channel errors. On the other hand, most existing algorithms cannot conceal the whole missing frame effectively. To resolve this problem, this paper proposes a new Adaptive Prediction Unit-based Motion Vector Extrapolation (APMVE) algorithm to restore the entire missing frame encoded by High Efficiency Video Coding (HEVC). In each missing HEVC frame, it uses the prediction unit (PU) information of the previous frame to adaptively decide the size of a basic unit for error concealment and to provide a more accurate estimation for the motion vector in that basic unit than can be achieved by any other conventional method. The simulation results showed that it is highly effective and significantly outperforms other existing frame recovery methods in terms of both objective and subjective quality.