• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.840-866
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• 2014

Visibility in underwater images is usually poor because of the attenuation of light in the water that causes low contrast and color variation. In this paper, a new approach for underwater image quality improvement is presented. The proposed method aims to improve underwater image contrast, increase image details, and reduce noise by applying a new method of using contrast stretching to produce two different images with different contrasts. The proposed method integrates the modification of the image histogram in two main color models, RGB and HSV. The histograms of the color channel in the RGB color model are modified and remapped to follow the Rayleigh distribution within certain ranges. The image is then converted to the HSV color model, and the S and V components are modified within a certain limit. Qualitative and quantitative analyses indicate that the proposed method outperforms other state-of-the-art methods in terms of contrast, details, and noise reduction. The image color also shows much improvement.

• Journal of the Korean institute of surface engineering
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• v.39 no.2
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• pp.82-86
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• 2006

Diamond films were deposited on 10.0$\times$10.0$mm^2$ pretreated (100) Si substrate using $CH_4$, $H_2$ and $O_2$ source gases in a horizontal-type microwave plasma enhanced chemical vapor deposition system. We introduced a cyclic on/off modulation of $CH_4$ and/or $O_2$ flows is a function of the reaction time during the initial deposition stage. Surface morphology and diamond quality of the films were investigated as a function of the different cyclic modulation process of the source gases flows: For the enhancement of the nucleation density, there is an optimal process for the incorporation of oxygen. Diamond qualities of the films were improved by introducing oxygen gas during the initial deposition stage.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.2
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• pp.220-225
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• 2010

This paper deals with the robust stability analysis of STATCOM (Static Synchronous Compensator) power system for power quality enhancement and power system stability. The STATCOM plays an important role in controlling the reactive power flow to the power network and hence the system voltage fluctuations and stability. The control areas of this plant are very large and the overall composition of the system is nonlinear. Also, STATCOM is influence of the uncertainties so that it is necessary to apply the new control technique. For solving these problems, we perform the fuzzy modeling and robust analysis for STATCOM system.

• Journal of IKEEE
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• v.26 no.2
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• pp.292-298
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• 2022

There is a limit to improving the image quality through global processing of images taken under backlighting because too bright and dark parts are mixed in one scene. This paper introduces a method to improve the quality of a photo by making two virtual images that improve the dark and bright areas of a backlit photo, and fusing them with the original image into a Laplacian pyramid. The proposed method reduces the computational burden by using histogram stretching and gamma transformation that can be simplified with LUT when creating the two virtual images. In addition, in order to obtain a color-enhanced image, contrast conversion was performed only on the luminance using the HSV coordinate system. The proposed technique showed its effectiveness by calculating several NIQA indicators using standard image data sets.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.2
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• pp.117-129
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• 2024

In this paper, we survey recent trends of International Global Navigation Satellite System (GNSS) organizations such as the International Committee on GNSS (ICG), International Civil Aviation Organization (ICAO), International Maritime Organization (IMO), and International Telecommunication Union (ITU), and investigate their impact on the maritime and aviation sectors. Each international organization promotes international cooperation, improvement of service quality, assurance of security, compliance with international regulations, and technological innovation and development. ICG develops a variety of satellite navigation enhancement systems. ICAO establishes international aviation regulations and standards to enhance aviation safety and security. IMO establishes international shipping conventions and rules to protect and regulate the shipping environment. Lastly, ITU establishes international communication regulations and standards. Investigation of such international organizations plays an important role in increasing the efficiency and reliability of GNSS systems. Each international organization promotes international cooperation, improvement of service quality, assurance of security, compliance with international regulations, and technological innovation and development. In the future, interoperability and compatibility with new satellite navigation systems and other GNSS and satellite navigation enhancement systems must be secured, so and thus investigation of international organizations must be conducted first.

• Journal of KIISE:Software and Applications
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• v.29 no.4
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• pp.235-247
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• 2002

For an efficient indexing and retrieval of digital video data, research on video caption extraction and recognition is required. This paper proposes methods for extracting artificial captions from video data and enhancing their image quality for an accurate Hangul and English character recognition. In the proposed methods, we first find locations of beginning and ending frames of the same caption contents and combine those multiple frames in each group by logical operation to remove background noises. During this process an evaluation is performed for detecting the integrated results with different caption images. After the multiple video frames are integrated, four different image enhancement techniques are applied to the image: resolution enhancement, contrast enhancement, stroke-based binarization, and morphological smoothing operations. By applying these operations to the video frames we can even improve the image quality of phonemes with complex strokes. Finding the beginning and ending locations of the frames with the same caption contents can be effectively used for the digital video indexing and browsing. We have tested the proposed methods with the video caption images containing both Hangul and English characters from cinema, and obtained the improved results of the character recognition.

• The Journal of the Acoustical Society of Korea
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• v.40 no.3
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• pp.234-240
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• 2021

In this paper, the mask-based speech enhancement is improved for effective speech recognition in noise environments. In the mask-based speech enhancement, enhanced spectrum is obtained by multiplying the noisy speech spectrum by the mask. The VoiceFilter (VF) model is used as the mask estimation, and the Spectrogram Inpainting (SI) technique is used to remove residual noise of enhanced spectrum. In this paper, we propose a combined loss to further improve speech enhancement. In order to effectively remove the residual noise in the speech, the positive part of the Triplet loss is used with the component loss. For the experiment TIMIT database is re-constructed using NOISEX92 noise and background music samples with various Signal to Noise Ratio (SNR) conditions. Source to Distortion Ratio (SDR), Perceptual Evaluation of Speech Quality (PESQ), and Short-Time Objective Intelligibility (STOI) are used as the metrics of performance evaluation. When the VF was trained with the mean squared error and the SI model was trained with the combined loss, SDR, PESQ, and STOI were improved by 0.5, 0.06, and 0.002 respectively compared to the system trained only with the mean squared error.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.4
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• pp.120-127
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• 2005

Quality system management adapted by small and medium enterprises in Kangwon province to enhance the competitiveness was studied. Variance analysis on several questionnaire answers was performed. Motives for acquiring the accreditation, such as product export, adjustment to international trend, enhancement of brand/product recognition, CEO's mind change, and management innovation, have been changed significantly among business types. Mind changes after the accreditations were setting company's first priority on quality, enhanced recognition on compliance of in-house standards and regulations, employee's performance with the recognition of quality. Amongst service problems to maintain the accreditations were difficulties in maintaining the recognition of the company's quality management, labor increase to maintain the ISO 9000 enforcement team, and financial burden to keep the accreditation. Quality recognition after the accreditations was significantly improved in setting company's first priority on quality, enhanced recognition on compliance of in-house standards and regulations, employee's performance with the recognition of quality.

• Journal of Korea Multimedia Society
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• v.21 no.9
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• pp.1027-1034
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• 2018

CCTV has been known to possess high level of objectivity and utility. Hence, the government has recently focused on replacing low quality CCTV with higher quality ones or even by adding high resolution CCTV. However, converting all existing low-quality CCTV to high quality can be extremely costly. Furthermore, low quality videos prior to CCTV replacement are likely to be of poor quality and thus not utilized correctly. In order to solve these problems, this paper proposes a method to improve videos quality of images using SRGAN(Super Resolution Generative Advisory Networks). Through experiments, we have proven that it is possible to improve low quality CCTV videos clearly. For this experiment, a total of 4 types of CCTV videos were used and 10,000 images were sampled from each type. Those images could then be used for machine learning. The fact that the pre-process for machine learning has been done manually and the long time that required for machine learning seems to be complementary.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.327-340
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• 2015

Purpose : Recently, many quality issues are aroused in military forces, such as failures in K-series weapons, combat uniforms' defects and 40mm ammunition explosion accident. To address these problems, Defense Agency for Technology and Quality(DTaQ) introduced new systems such as Manufacturing Readiness Assessment(MRA), Test Report Information System(TRIS) and so on. However, these activities require the human and time resources which cannot be increased in short period. In this paper, we suggest more practical and efficient product examination method. Methods : The most popular and widely used government's quality assurance technique is a sampling method to examine the product. In this research, we first reviewed the DTaQ's quality assurance regulation, then identified several possible problems and finally suggested more efficient and effective sampling plans. Results : We have suggested new sampling framework and evaluated its performance on two military supplies by comparing with other sampling method, and observed that the number of tested samples can be substantially reduced. Therefore, required quality assurance time can be saved. Conclusion : In this paper, we first reviewed the product examination frameworks of DTaQ, PPQMS and DCMA. Then we identified several possible problems which can cause the loss of objectivity and time. To handle these problems, we suggested the new product examination framework and tested the framework to verify the performance.