• Journal of radiological science and technology
• /
• v.42 no.2
• /
• pp.119-130
• /
• 2019

Positron emission tomography (PET) is widely used imaging modality for effective and accurate functional testing and medical diagnosis using radioactive isotopes. However, PET has difficulties in acquiring images with high image quality due to constraints such as the amount of radioactive isotopes injected into the patient, the detection time, the characteristics of the detector, and the patient's motion. In order to overcome this problem, we have succeeded to improve the image quality by using the dynamic image reconstruction method based on singular value decomposition. However, there is still some question about the characteristics of the proposed technique. In this study, the characteristics of reconstruction method based on singular value decomposition was estimated over computational simulation. As a result, we confirmed that the singular value decomposition based reconstruction technique distinguishes the images well when the signal - to - noise ratio of the input image is more than 20 decibels and the feature vector angle is more than 60 degrees. In addition, the proposed methode to estimate the characteristics of reconstruction technique can be applied to other spatio-temporal feature based dynamic image reconstruction techniques. The deduced conclusion of this study can be useful guideline to apply medical image into SVD based dynamic image reconstruction technique to improve the accuracy of medical diagnosis.

• Journal of the Korean Society of Radiology
• /
• v.17 no.2
• /
• pp.215-221
• /
• 2023

Among brain CT scan conditions including the lens, the tube voltage was changed to 80, 100, and 120 kVp and applied. The change in dose was analyzed using lead, lead goggles and barium sulfate silicon shielding materials, and the degree of influence of the shielding materials on image quality was compared and analyzed by applying the SNR, CNR, and SSIM index analysis methods. As a result, it was analyzed that although the dose was reduced by applying all shielding materials, the difference in dose reduction was not large (P > 0.05). In addition, as for the change in image quality due to the application of the shielding material, SNR and CNR were the highest when lead goggles were applied, and the structural similarity was measured to be the best as it was closest to the reference value of 1 in SSIM analysis. Therefore, based on the results of this study, it is thought that if more diverse shielding materials and clinical test results are derived and applied, it will be helpful for the clinical application criteria in the case of shielding utilization inspection.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.16 no.2
• /
• pp.225-233
• /
• 1998

It is necessary to check the water quality of the lake on a continuous basis to determine the appearance of water pollution; however, it not only takes much time and expenses but it is considerably difficult to investigate the wide range of the area. If we use the remote sensing technique through the use of satellites, the status of water quality can be checked covering many wide areas simultaneously; and because the same area can be measured on a periodic basis, it is extremely effective in investigating the water quality. Furthermore, as some of the Landsat sensors carry characteristics which sense objects according to wave length, the distribution of water quality can be checked relatively accurately within a short period of time, while its image can be displayed in color. Hence, this research has attempted to extract water quality elements, such as transparency, water depth, and surface water temperature by utilizing the satellite data, and has prepared the water quality distribution image map of the Lake Hwajinpo by presenting the related empirical formula of the water quality elements. If the water quality distribution image map is prepared after extracting the water quality elements from the DN of the Landsat TM image and then carrying out TIN analysis through the use of GIS, relatively more accurate pattern can be learned covering a wide rage of area than the pattern presented based on the value obtained from actual observation.

• Korean Journal of Remote Sensing
• /
• v.27 no.5
• /
• pp.587-599
• /
• 2011

As one measure of image interpretability, NIIRS(National Imagery Interpretability Rating Scale) has been used. Unlike MTF(Modulation Transfer Function), SNR(Signal to Noise Ratio), and GSD(Ground Sampling Distance), NIIRS can describe the quality of overall image at user's perspective. NIIRS is observed with human observation directly or estimated by edge analysis. For edge analysis specially manufactured artificial target is used commonly. This target, formed with a tarp of black and white patterns, is deployed on the ground and imaged by the satellite. Due to this, the artificial target-based method needs a big expense and can not be performed often. In this paper, we propose a new edge analysis method that enables to estimate NIIRS accurately. In this method, natural targets available in the image are used and characteristics of the target are considered. For assessment of the algorithm, various experiments were carried out. The results showed that our algorithm can be used as an alternative to the artificial target-based method.

• Journal of radiological science and technology
• /
• v.44 no.6
• /
• pp.655-661
• /
• 2021

Positron emission tomography (PET) images is affected by acquisition time, short acquisition times results in low gamma counts leading to degradation of image quality by statistical noise. Noise2Void(N2V) is self supervised denoising model that is convolutional neural network (CNN) based deep learning. The purpose of this study is to evaluate denoising performance of N2V for PET image with a short acquisition time. The phantom was scanned as a list mode for 10 min using Biograph mCT40 of PET/CT (Siemens Healthcare, Erlangen, Germany). We compared PET images using NEMA image-quality phantom for standard acquisition time (10 min), short acquisition time (2min) and simulated PET image (S2 min). To evaluate performance of N2V, the peak signal to noise ratio (PSNR), normalized root mean square error (NRMSE), structural similarity index (SSIM) and radio-activity recovery coefficient (RC) were used. The PSNR, NRMSE and SSIM for 2 min and S2 min PET images compared to 10min PET image were 30.983, 33.936, 9.954, 7.609 and 0.916, 0.934 respectively. The RC for spheres with S2 min PET image also met European Association of Nuclear Medicine Research Ltd. (EARL) FDG PET accreditation program. We confirmed generated S2 min PET image from N2V deep learning showed improvement results compared to 2 min PET image and The PET images on visual analysis were also comparable between 10 min and S2 min PET images. In conclusion, noisy PET image by means of short acquisition time using N2V denoising network model can be improved image quality without underestimation of radioactivity.

• The Journal of the Korea Contents Association
• /
• v.16 no.7
• /
• pp.681-688
• /
• 2016

This study assess their quality of radiation on analysis of the spectrum of resolution suggesting IEC 61267 in radiation quality that RQA3, RQA5, RQA7, RQA9 and combination of clinical condition using several quality of radiation. In experiments edge method first, the spatial resolution assessment used image of the additional filter and SID is obtained the IEC 62220-1, spatial resolution and sharpness of the obtained image was evaluated in the MTF value 10%(0.1), MTF value 50%(0.5) using a Matlab program. Second, MCNPX simulation used spatial resolution analysis was radiation quality particle fluence and spectrum analysis in energy. As a result, make use of additional filter, image quality evaluation of SID that RQA3 radiation quality combination qualification is higher spatial resolution and sharpness make unused of additional filter and SID 100cm. RQA7 radiation quality combination qualification is higher that spatial resolution make unused of additional filter and SID 150cm. RQA9 radiation quality combination qualification is higher that spatial resolution and sharpness make used of additional filter and SID 180cm. spectrum analysis of radiation quality by reducing consequent errors occurring in the experiment that error due to the reproducibility of the X-ray tube, occur in an error of correction the detector suggest ideal conditions from spectrum analysis through MCNPX simulation. In conclusion, by suggesting spatial resolution and sharpness of result for various radiation quality, It provide basic data that radiation quality condition and quantitative assessment method for laboratory in clinical using detector evaluation.

• Culinary science and hospitality research
• /
• v.22 no.7
• /
• pp.47-57
• /
• 2016

This study was conducted to verify the relationships among the image of middle-low price chain hotels, service quality, consumption value, and customer emotion by using the AMOS 22.0 statistic package program. Confirmatory factor analysis and structural equation modeling methods employed for identifying the formulated hypothesis model. According to results, first, it is seen that the image of middle-low price chain hotels has positive effect on the service quality. Second, the image of middle-low price chain hotels has positive effect on the consumption value, and the consumption value has positive effect on the service quality. Third, the service quality does not have positive effect on the customer emotion. Last, the image of middle-low price chain hotels has positive effect on the customer emotion. In this study, we attempted to establish the management strategy device of middle-low price chain hotels by analyzing how the image of middle-low price chain hotels affect the service quality, consumption value, and customer emotion. As a result, when it comes to the service quality according to the image of middle-low price chain hotels, the conviction, in other words, the belief of the hotel staffs was the biggest one. In addition, when it comes to the consumption value according to the image of middle-low price chain hotels, the functional value, the kind service of the hotel staffs was seen as the highest satisfaction. More practical and theoretical implications for developing marketing strategy in context of middle-low price chain hotels has been suggested in conclusions.

• Proceedings of the Korean Society for Quality Management Conference
• /
• 2004.04a
• /
• pp.25-30
• /
• 2004

This study analyzes a change and an effect that brand image gets in product choose. Purpose of this study present the suggestion under the influence of degree that brand image gets in product purchase to cosmetic customer. Consumers investigate the product or trademark when purchase goods. They purchase goods through the comparison and analysis and evaluate the satisfaction and dissatisfaction with the contentment. Consumers complicate while compare the products and the consumer's choose the products. The purpose of this study is find various requirement of consumers and present efficient marketing activity through theoretical verification and actual proof analysis.

• Journal of Distribution Science
• /
• v.19 no.5
• /
• pp.61-68
• /
• 2021

Purpose: Retailing is one of the fastest-growing sectors in Vietnam. In the sight of foreign investors, the Vietnamese retailing market is very prospective. However, the current competition is very intensive, and retailers are keen on gaining new customers. Hence, Vietnamese retailers have paid more attention to customer loyalty. Saigon Co.op is one of the largest retailers in Vietnam, but its consumers have more choices over a retailer. As a result, Saigon Co.op has realized the significance of customer loyalty. This study aims to determine the factors impacting customer loyalty of Saigon Co.op supermarket in Vietnam. Research design, data and methodology: this study applied the multiple regression analysis with 250 samples collected from Saigon Co.op customers. The questionnaire is provided to respondents via Google Form, and the link is sent to the fan page of Co.op mart on Facebook. Two hundred eighty-seven samples were collected, but 37 samples were removed due to missing values. Exploratory Factor Analysis (EFA) and regression analysis are used for data analysis on SPSS software version 20. Results: The findings show all four determinants of Saigon Co.op's customer loyalty, including Product Quality, Brand Image, Price Strategy and Service Quality. Conclusions: managerial recommendations are provided for supermarkets to improve their customer loyalty in Vietnam and other emerging markets. Limitations and suggestions for further research are also discussed.

• The Research Journal of the Costume Culture
• /
• v.22 no.4
• /
• pp.640-653
• /
• 2014

The purpose of this study was to investigate the effect of store attributes on brand equity of and brand attitude toward Korean SPA brands. Data were collected from women living in Seoul in ages from 18 to 39 with purchasing experience at Korean SPA brands. A total of 554 questionnaires were used in the statistical analysis including factor analysis and structure equation analysis. The results were as follows: For store attributes, 8 factors were extracted: product assortment, fashionability, price, quality, store environment, service, convenience in location and advertisement. Two factors, brand awareness, brand image were extracted for brand equity, and brand attitude was derived as a single dimension. Product-related store attributes such as product assortment, price, quality have positive effects on brand awareness, brand image and brand attitude. Other attribute such as store environment has positive effect on brand awareness and brand image, Attribute such as advertisement has positive effect on brand awareness and service, convenience in location have positive effect on brand attitude. Moreover, brand image and brand awareness have positive effect on brand attitude. These results indicate the product-related attributes are important factors to consider for improving brand equity and brand attitude for Korean SPA brands.