• Journal of the Korean Society of Radiology
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• v.18 no.6
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• pp.681-690
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• 2024

This study aimed to quantitatively analyze the effect of anode angle on the heel effect and image quality in digital radiography systems. For this purpose, two X-ray devices with anode angles of 12° and 16° (Accuray D6 and INNOVISION-SH) were used to compare the radiation dose distribution and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in thoracic spine images, using a chest phantom under identical imaging conditions. In the radiation dose distribution study, it was observed that the device with a 12° anode angle showed more pronounced dose distribution non-uniformity, with a sharp decrease in dose from the cathode side to the anode side. In contrast, the 16° anode angle device exhibited a more gradual dose decrease and a more uniform distribution than the 12° device. It was confirmed that a smaller anode angle intensified the heel effect, causing the radiation intensity to be distributed unevenly. In the thoracic spine image analysis, it was found that, with an anode angle of 16°, the SNR and CNR improved when the chest phantom was placed in the standard orientation (T12 on the cathode side and T1 on the anode side). This suggests that the anode angle and patient positioning influence the effect of the heel effect on image quality. Compared to the reverse orientation (T1 on the cathode side and T12 on the anode side), the standard orientation provided superior image quality. Based on these findings, it is recommended that, in clinical practice, awareness of the anode angle and accurate differentiation between standard and reverse positioning during thoracic spine imaging with digital radiography systems can enhance image quality and improve diagnostic reliability.

• Journal of Distribution Science
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• v.18 no.1
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• pp.15-26
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• 2020

Purpose: This study is to analyze the image classification using Convolution Neural Network and Transfer Learning for Jeju Island and to suggest related implications. As the biggest tourist destination in Korea, Jeju Island encounters environmental issues frequently caused by marine debris along the seaside. The ever-increasing volume of plastic waste requires multidirectional management and protection. Research design, data and methodology: In this study, the deep learning CNN algorithm was used to train a number of images from Jeju clean and polluted beaches. In the process of validating and testing pre-processed images, we attempted to explore their applicability to coastal tourism applications through probabilities of classifying images and predicting clean shores. Results: We transformed and augmented 194 small image dataset into 3,880 image data. The results of the pre-trained test set were 85%, 70% and 86%, and then its accuracy has increased through the process. We finally obtained a rapid convergence of 97.73% and 100% (20/20) in the actual training and validation sets. Conclusions: The tested algorithms are expected to implement in applications for tourism service distribution aimed at reducing coastal waste or in CCTVs as a detector or indicator for residents and tourists to protect clean beaches on Jeju Island.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.260-262
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• 2002

An accurate measurement of dose distribution is indispensable to perform radiation therapy planning. A measurement technique using a radiographic film, which is called a film dosimetry, is widely used because it is easy to obtain a dose distribution with a good special resolution. In this study, we tried to develop an analyzing system for the film dosimetry using usual office automation equipments such as a personal computer and an image scanner. A film was sandwiched between two solid water phantom blocks (30 ${\times}$ 30 ${\times}$ 15cm). The film was exposed with Cobalt-60 ${\gamma}$-ray whose beam axis was parallel to the film surface. The density distribution on the exposed film was stored in a personal computer through an image scanner (8bits) and the film density was shown as the digital value with NIH-image software. Isodose curves were obtained from the relationship between the digital value and the absorbed dose calculated from percentage depth dose and absorbed dose at the reference point. The isodose curves were also obtained using an Isodose plotter, for reference. The measurements were carried out for 31cGy (exposure time: 120seconds) and 80cGy (exposure time: 300seconds) at the reference point. While the isodose curves obtained with our system were drawn up to 60% dose range for the case of 80cGy, the isodose curves could be drawn up to 80% dose range for the case of 31cGy. Furthermore, the isodose curves almost agreed with that obtained with the isodose plotter in low dose range. However, further improvement of our system is necessary in high dose range.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.58-71
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• 1999

When the same image is displayed in many different devices, the reproduced colors are not same due to the differences in the gamut between devices. Therefore, many gamut mapping method were proposed to solve this problem. In this paper, color discrimination enhancement gamut mapping method using color distribution rearrangement is proposed to reduce the unnecessary distortions by compression mapping and to minimize the decrease of color discrimination by clipping method. The proposed method constructs color distribution, the 3-dimension array of input image's colors. if the maximum of color distribution is within the boundary of printer gamut. the colors are mapped to the same colors. Otherwise, out-of-gamut colors are compressed into the printer gamut with minimum distortion. Consequently, the printer output image was highly consistent with the corresponding monitor image and had an enhanced color discrimination in region where high chroma varied linearly.

• Journal of Biomedical Engineering Research
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• v.19 no.2
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• pp.113-118
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• 1998

By their rapid and periodic actions, the cilia of the human respiratory tract play an important role in clearing inhaled noxious particles. Based on the automated image-processing technique, we studied the method analyzing ciliary beat frequency (CBF) objectively and quantitatively. Microscopic ciliary images were transformed into digitized gray ones through an image-grabber, and from these we extracted signals for CBF. By means of a FFT, maximum peak frequencies were detected as CBFs in each partitioned block for the entire digitized field. With these CBFs, we composed distribution maps visually showing the spatial distribution of CBFs. Through distribution maps of CBF, the whole aspects of CBF changes for cells and the difference of CBF of neighboring cells can be easily measured and detected. Histogram statistics calculated from the user-defined polygonal window can show the local dominant frequency presumed to be the CBF of a cell or a crust the region includes.

• Communications for Statistical Applications and Methods
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• v.8 no.2
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• pp.573-579
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• 2001

Wavelet thresholding is a method for he reduction of noise in image. Wavelet coefficients of image are correlated in local characterization. Thee correlations also appear in he original pixel representation of the image, and they do not follow from the characterizations of the wavelet transform. In this paper, we compare noise-free distributions of Bayes approach to improve the classical threshold algorithm.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1390-1393
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• 1987

This paper describes the image data compression based on the image decomposition. We reduced the processing time using the segmentation based on the distribution of grey level, and obtained high compression rate using the Huffman run-length coding for the segmented image, and the 2-Dimensional least square curve fitting and the shift coder for each region.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.373-374
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• 2007

This paper proposes a natural contrast enhancement algorithm that preserves the brightness of an image. In the case that an image has the partially dense distribution of intensity, conventional contrast enhancement algorithms degrade the image quality because they excessively change the intensity values. In contrast to convention algorithms, the proposed method is able to obtain a natural image with the high contrast using the concept of brightness preservation. The experimental results show the effectiveness of our algorithm.

• Journal of Distribution Science
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• v.12 no.1
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• pp.21-28
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• 2014

Purpose - This study aims to examine the Indian consumers'mall shopping patronage with the application of theory of planned behavior (TPB). The research intends to extend the TPB components (attitude, self-efficacy, subjective norms) with the addition of self-image and study their effect on Indian consumers' mall patronage intention. Research design, data and methodology - The research employed factor analysis to verify correct loading of items on corresponding factors and to confirm the applicability of constructs in the Indian context. The model was tested using stepwise regression analysis. Results -The results indicate a positive relationship between self-efficacy and intention to mall patronage. The findings show that self-image, attitude, self-efficacy, subjective norm significantly influence the mall patronage intention. Self-efficacy, which signifies self-competence and confidence in one's ability as a mall shopper indicates that as the self-efficacy increases Indian consumers' will eventually patronize malls. Conclusions - Self-image congruency plays a salient role in predicting mall-shopping patronage. The mall management should ensure that the mall marketing strategies incorporate it along with the other components of TPB to warrant decent footfall.

• Journal of Distribution Science
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• v.16 no.12
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• pp.23-31
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• 2018

Purpose - The purpose of this study was to set brand awareness and brand image as independent variables from Keller's (1993) definition of brand equity and to analyze whether those variables have an influence on customer satisfaction and customer loyalty with perceived quality and value as mediator variables. Research design, data, and methodology - Data is collected through questionnaires from 200 of responders. Survey respondents were young people who use convenience stores. Questionnaires were tested in October 2017. SPSS and AMOS were used for structural equation as an analysis method. Results - The analysis results specified above can be summarized as follows: 1) Brand awareness had statistically significant influence on perceived quality and perceived value; 2) Brand image had a positive (+) influence on perceived quality and had no significant influence on perceived value; 3) Perceived quality and perceived value had a significant influence on customer satisfaction, and customer satisfaction had a statistically significant influence on customers' repurchase intention. Conclusions - Brand awareness and brand image had an influence on young consumers' decision-making process for purchasing PB food products. Convenience stores have to focus on developing food products with brand awareness and brand image more suitable for satisfying consumer preferences.