• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.425-432
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• 2024

In this study, we propose a self-restoring friction slit damper by combining the concepts of self-restoring dampers, friction dampers, and steel dampers that are currently used and researched. For this purpose, an innovative damper structure was designed using superelastic shape memory alloy for automatic recovery and combining the concepts of friction damper and slit damper. Afterwards, detailed design was carried out and variables such as material, with of strut, and bolt fastening force were set. Modeling was performed using the ABAQUS program for a total of 12 dampers, and finite element analysis was performed by substituting the designed loading protocol. As a result, the self-recovering friction slit damper using superelastic shape memory alloy was excellent in terms of load, but the energy dissipation ability was not significantly secured due to the excellent recovery performance. However, friction slit dampers made of Gr.50 steel have dramatically improved performance in terms of load and energy dissipation through innovative structural improvements. Through this, the innovative structure of the damper, which combines the mechanisms of a friction damper and a steel damper, was demonstrated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.2
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• pp.43-48
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• 2016

Operational applications such as service restoration, voltage control and protection coordination are calculated based on the active and reactive power loading of the sections in the distribution networks. Loadings of the sections are estimated using the voltage and current measured from the automatic switches deployed along the primary feeders. But, due to the characteristics of the potential transformer attached to the switches, accuracy of the voltage magnitude is not acceptable to be used for section loading calculation. This paper proposes a new accurate section loading estimation method through voltage measurement error compensation by calculating voltage drop of the distribution line. In order to establish feasibility of the proposed method, various case studies based on Matlab simulation have been performed.

• Journal of Korea Multimedia Society
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• v.7 no.12
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• pp.1639-1649
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• 2004

In this paper, a method for detection of forged signatures based on spectral analysis of directional gradient density function and a weighted fuzzy classifier is proposed. The well defined outline of an incoming signature image is extracted in a preprocessing stage which includes noise reduction, automatic thresholding, image restoration and erosion process. The directional gradient density function derived from extracted signature outline is highly related to the overall shape of signature image, and thus its frequency spectrum is used as a feature set. With this spectral feature set, having a property to be invariant in size, shift, and rotation, a weighted fuzzy classifier is evaluated for the verification of freehand and random forgeries. Experiments show that less than 5% averaged error rate can be achieved on a database of 500 signature samples.

• KIEE International Transactions on Power Engineering
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• v.4A no.1
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• pp.42-47
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• 2004

This paper presents the various application programs for the Distribution Automation System (DAS) of the Korea Electric Power Corporation (KEPCO)'s distribution system. These programs are developed to allow for optimal operation in the areas of feeder automation, relay coordination, loss minimization and so on. They are single line diagram auto creation programs for the feeder, service restoration program, protection coordination program, data error detection program, and optimal network reconfiguration program. The details of these programs are presented for validity and effectiveness.

• Journal of the Speleological Society of Korea
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• no.85
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• pp.15-17
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• 2008

This paper is attempted to review a cave restoration and preservation plan against environmental destruction and pollution as a preliminary survey for preservation of cave environment. Consequently, it's important to throw an indirect light rather than direct light on cave formations, keeping distance of 2m at least. The already existing moss should be removed using wet cloth or sponge as soon as possible. If it's washed off, be careful not to splash it or water on nearby subjects. Based on an automatic switch-off system, light will automatically turn off when no one is left in the cave. It's also recommended to dualize the cave passage and partially close the cave by taking turns to give a time to recover.

• Korean Journal of Remote Sensing
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• v.3 no.1
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• pp.25-39
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• 1987

The purpose of this research is to develop the Automatic Fingerprint Verfication System by digital computer based on specially in PC level. Fingerprint is used as means of personal identity verification in view of that it has the high reliability and safety. Fingerprint pattern recognition algorithm is constitute of 3 stages, namely of the preprocessing, the feature extraction and the recognition. The preprocessing stage includes smoothing, binarization, thinning and restoration. The feature extraction stage includes the extraction of minutiae and its features. The recognition stage includes the registration and the matching score calculation which measures the similarity between two images. Tests for this study with 325 pairs of fingerprint resulted in 100% of separation which which in turn is turned out to be the reliability of this algorithm.

• International Journal of Advanced Culture Technology
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• v.7 no.1
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• pp.64-69
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• 2019

With the advent of the fourth industry, the need for office automation with automatic character recognition capabilities is increasing day by day. Therefore, in this paper, we study a character recognition algorithm that effectively recognizes a new experimental data character by using learning data characters. The proposed algorithm computes the degree of similarity that the structural regions of learning data characters match the corresponding regions of the experimental data character. It has been confirmed that satisfactory results can be obtained by selecting the learning data character with the highest degree of similarity in the matching process as the final recognition result for a given experimental data character.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.89-96
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• 2021

In various areas of the 4th industry, a big issue is software quality enhancement for stability and reliability of the smart software systems. After revising software promotion law at 2020, we must clearly define requirements and separate design parts and implementation parts of an all public software development contracts. In this study, we need to validate whether the final implementation of software is followed by the original design or not. To do this, we consider the design restoration through software visualization based on reverse engineering. Therefore we propose an UML design extraction and visualization method based on reverse engineering. Based on this, we may validate whether it is implemented according to the original design, and how much visualizes and includes the code the internal complexity for improvement of software quality.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.118-123
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• 2021

Recently, digital crime is becoming more intelligent, and efficient digital forensic techniques are required to collect evidence for this. In the case of important files related to crime, a specific person may intentionally delete the file. In such a situation, data recovery is a very important procedure that can prove criminal charges. Although there are various methods to recover deleted files, we focuses on the recovery technique using HxD editor. When recovering a deleted file using the HxD editor, check the file structure and access the file data area through calculation. However, there is a possibility that errors such as arithmetic errors may occur when a file approach through calculation is used. Therefore, in this paper, we propose an algorithm that automatically calculates the header and footer of a file after checking the file signature in the root directory for efficient file recovery. If the algorithm proposed in this paper is used, it is expected that the error rate of arithmetic errors in the file recovery process can be reduced.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.6 s.312
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• pp.26-33
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• 2006

Film restoration is to detect the location and extent of defected regions from a given movie film, and if present, to reconstruct the lost information of each region. It has gained increasing attention by many researchers, to support multimedia service of high quality. In general, an old film is degraded by dust, scratch, flick, and so on. Among these, the most frequent degradation is the scratch. So far techniques for the scratch restoration have been developed, but they have limited applicability when dealing with all kinds of scratches. To fully support the automatic scratch restoration, the system should be developed that can detect all kinds of scratches from a given frame of old films. This paper presents a neurual network (NN)-based texture classifier that automatically detect all kinds of scratches from frames in old films. To facilitate the detection of various scratch sizes, we use a pyramid of images generated from original frames by having the resolution at three levels. The image at each level is scanned by the NN-based classifier, which divides the input image into scratch regions and non-scratch regions. Then, to reduce the computational cost, the NN-based classifier is only applied to the edge pixels. To assess the validity of the proposed method, the experiments have been performed on old films and animations with all kinds of scratches, then the results show the effectiveness of the proposed method.