• The Korean Journal of Nuclear Medicine Technology
• /
• v.20 no.1
• /
• pp.20-23
• /
• 2016

Purpose Because of heart movement, PET image of heart is very blur. So, PET scan gated with ECG is necessary to improve a spatial resolution of heart PET image. In this study, we will evaluate a image quality of both gated $^{13}N-ammonia$ PET scan and non-gated one. Materials and Methods Before start a heart PET, we attached a ECG electrode on patients (n = 5, $aged=54{\pm}17$). And we started a list mode PET scan that used by a mCT40 PET/CT (siemens, germany) during 10 minute, injected $^{13}N-ammonia$ ($378{\pm}50MBq$) to a patients at same time. By using this list mode data, we reconstructed both gated PET image and non-gated PET image. Then we analysed a profiles of those images, performed a blind test, and subtracted a gated image on non-gated image. Results FWHM of a gated image is improved about 23% and there is a differency count distribution at a subtracted image from non-gated image to a gated image. But in case of blind test, everybody select the gated image as a better quality among each images. Conclusion As a result, we can find that image quality will improve by using gated PET scan. In additional, we can calculate a EF valve, apply QGS, QPS of PET. Therefore, the gated PET scan help improving an accuracy, applying a more information for a diagnosis.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.4 s.316
• /
• pp.26-34
• /
• 2007

Intelligent projection system indicates a system that displays desired images on an arbitrary screen in an arbitrary environment using projector without noticeable image distortion. In recent years, projectors have become widespread and ubiquitous due to their increasing capabilities and declining cost. Moreover, the size of projectors is getting smaller and handhold projectors are emerging. Thanks to these advances, the demand for intelligent projection system has been significantly increased and the demand has led to remarkable progress of the related techniques or technologies to intelligent projection system However, there are still some environments (or conditions, mainly dynamic ones) that intelligent projections systems cannot handle and they have limited the application area of intelligent projection systems. This paper exemplifies such environments (e.g. specular screen, dynamic screen) and propose effective solutions (i.e. multiple overlapping projectors, complementary pattern embedding) for thor And the usefulness of the solutions is verified through experimental results and user evaluation. Notice that the environments are considered not simultaneously but independently because it is impossible to consider them simultaneously by simply combining the solutions for each. Acually, a totally different solution would be necessary to consider them simultaneously. Therefore, we expect that the proposed methods would largely extend the application area of intelligent projection systems except for severely arbitrary environment.

• Journal of Navigation and Port Research
• /
• v.34 no.3
• /
• pp.213-220
• /
• 2010

Following the application of Formal Safety Assessment(FSA) to bulk carriers, crude oil tankers and large passenger ships, an urgent need to consider the safety of general cargo ships has recently been raised through the International Maritime Organization(IMO)(IMO, 2006a), and related FSA studies are being carried out by International Association of Classification Societies(IACS) as a preparatory work for the discussion on the issue of general cargo ship safety in the IMO committee. FSA is a structured and systematic methodology which is based on the techniques of risk analysis and cost benefit assessment to assist in the decision-making process, and aims at enhancing maritime safety, including protection of life, health, the marine environment and property. FSA can be used as a tool to facilitate the development of regulatory changes equitable to the various parties, with a view to aiding the achievement of consensus, and to help in the evaluation of new regulations and in making a comparison between existing and possibly improved regulations(IMO, 2007). This study aims at verifying the usefulness of FSA methods as a tool to conduct a safety assessment of general cargo ships flying the Korean flag, and providing useful information on 'the safety of general cargo ships' for IMO committee's discussion on the matter at a future session. FSA comprises five steps, however, steps 1(Hazard identification) and 2 (Risk analysis) from the FSA study for the Korean-flagged general cargo ships are discussed in this paper.

• The KIPS Transactions:PartD
• /
• v.15D no.4
• /
• pp.485-494
• /
• 2008

Huge amounts of various web items such as keywords, images, and web pages are being made widely available on the Web. The popularities of such web items continuously change over time, and mining temporal patterns in popularities of web items is an important problem that is useful for several web applications. For example, the temporal patterns in popularities of search keywords help web search enterprises predict future popular keywords, enabling them to make price decisions when marketing search keywords to advertisers. However, presence of millions of web items makes it difficult to scale up previous techniques for this problem. This paper proposes an efficient method for mining temporal patterns in popularities of web items. We treat the popularities of web items as time-series, and propose gapmeasure to quantify the similarity between the popularities of two web items. To reduce the computation overhead for this measure, an efficient method using the Fast Fourier Transform (FFT) is presented. We assume that the popularities of web items are not necessarily following any probabilistic distribution or periodic. For finding clusters of web items with similar popularity trends, we propose to use a density-based clustering algorithm based on the gap measure. Our experiments using the popularity trends of search keywords obtained from the Google Trends web site illustrate the scalability and usefulness of the proposed approach in real-world applications.

• Journal of the Korean Society of Radiology
• /
• v.17 no.7
• /
• pp.1033-1039
• /
• 2023

Low-dose chest CT, which is used as a lung screening test, also includes information on coronary artery calcification within the scan range. The purpose of this study was to investigate the usefulness of determining coronary artery calcification using Low-dose chest CT. Those who underwent low-dose chest CT and coronary artery calcification score CT on the same day were eligible. Coronary artery calcium score CT results were divided into 4 groups (Low: 1〈CACS〈10, Mild: 10〈CACS〈100, Moderate: 100〈CACS〈400, High: 400〈CACS) by referring to the Coronary artery calcium score categories and risks. After selecting 30 people each group, five radiotechnologists with more than 15 years of experience in coronary artery calcium measurement retrospectively analyzed the presence or absence of coronary artery calcification in low-dose chest CT images. The results of the five observers' uniform interpretation of the low-dose chest CT image were consistent with the coronary artery calcium score CT results in Low group: 56%, Mild group: 96.6%, Moderate group: 100%, and High group: 100%. appeared. In the Low group, all 5 observers observed calcification in 17 out of 30 cases, and in 7 cases all 5 observers decided that calcification could not be identified. Coronary artery calcification could be observed in 100% of asymptomatic adults with a calcium score of 15 or higher in low-dose chest CT scans. The minimum calcium score that can be identified is 1, and it was found that even very small calcifications can be identified when the subject's body size is small or the scan is performed at a time when heart movement is minimal.

• Journal of Digital Convergence
• /
• v.11 no.12
• /
• pp.599-606
• /
• 2013

The purpose of this study is to know a clinical usefulness for delineation of articular cartilage compared with 2D TSE-SPIR and 3D FFE-PROSET technique. From January 2013 to september 2013, a total of 30 normal volunteers(12 men and 18 women aged between 35 and 55 years; mean 49.48 years) were studied on a philips 3.0T MRI scanner. As a quantitative analysis, SNRs and CNRs were evaluated by using two methods for delineation of articular cartilage. As a qualitative analysis, image quality was evaluated by special radiological technologist of MRI for image delineation on a three grade. As a results, SNRs and CNRs for articular cartilage were significantly greater for the 3D FFE-PROSET(SNRs: 8.40, 114.02, 9.53, CNRs: 104.49, 139.49) technique compared to 2D TSE-SPIR(SNRs: 4.41, 71.63, 7.34, CNRs: 64.30, 58.41) technique, image quality also was higher for evaluation of 3D FFE-PROSET(2.40) technique(p=0.0021). In conclusion, this study showed that a 3D FFE-PROSET MRI has improved SNRs and CNRs for evaluating of the articular cartilage, these conclusions in the future will be provided useful information in diagnosis of articular cartilage.

• Journal of the Korea Computer Graphics Society
• /
• v.27 no.3
• /
• pp.65-74
• /
• 2021

3D reconstruction means that reconstructing the 3D shape of the object in an image and a video. We proposed a progressive occupancy network architecture that can recover not only the overall shape of the object but also the local details. Unlike the original occupancy network, which uses a feature vector embedding information of the whole image, we extract and utilize the different levels of image features depending on the receptive field size. We also propose a novel network architecture that applies the image features sequentially to the decoder blocks in the decoder and improves the quality of the reconstructed 3D shape progressively. In addition, we design a novel decoder block structure that combines the different levels of image features properly and uses them for updating the input point feature. We trained our progressive occupancy network with ShapeNet. We compare its representation power with two prior methods, including prior occupancy network(ONet) and the recent work(DISN) that used different levels of image features like ours. From the perspective of evaluation metrics, our network shows better performance than ONet for all the metrics, and it achieved a little better or a compatible score with DISN. For visualization results, we found that our method successfully reconstructs the local details that ONet misses. Also, compare with DISN that fails to reconstruct the thin parts or occluded parts of the object, our progressive occupancy network successfully catches the parts. These results validate the usefulness of the proposed network architecture.

• Investigative Magnetic Resonance Imaging
• /
• v.17 no.2
• /
• pp.91-100
• /
• 2013

Purpose : To evaluate the usefulness of cervicothoracic spine sagittal T2-weighted images (CT SAG T2WIs) included in routine lumbar spine MRI. Materials and Methods: Institutional review board approval was obtained and informed consents were waived for this retrospective study. The study group comprised 2,113 patients who underwent lumbar spine MRI from January 2005 to December 2005. CT SAG T2WIs were added in the routine lumbar spine MRIs. Radiologic reports were reviewed retrospectively for pathologic lesions on CT SAG T2WIs by one radiologist. Information of additional cervical or thoracic spine MRI and/or CT for further evaluation of positive findings on CT SAG T2WIs and their treatment were collected by retrospectively reviewing medical records. Results: The CT SAG T2WIs revealed 142 pathologic lesions in 139 (6.58%) of the 2,113 patients. They were easily obtained without positional change in a scan time of less than 2 minutes. Additional cervical or thoracic spine MRI and/or CT for positive findings on CT SAG T2WIs were performed in 13 patients. Seven patients underwent surgical treatment. Conclusion: CT SAG T2WIs included in routine lumbar spine MRI were useful in finding the pathologic lesions in cervicothoracic spine for the patients who assumed to have lesions in lumbar spine.

• Journal of Convergence for Information Technology
• /
• v.8 no.1
• /
• pp.253-263
• /
• 2018

Textile fashion industry is a core foundation industry, having the majority of companies with 10 or more workers, in Northern Gyeonggi Province. however the industry is mostly comprised of small unit-stream enterprises, orders are greatly reduced due to lately accelerated overseas expansion of medium/large-sized vendors and the growth-inhibiting vicious circle has being set in, as this situation causes the reduction of investment. For resolving the problems, this study proposes required political factors and concrete policy proposals by designing AHP research model(4 layers and 36 elements), based on grasp of the transitional aspect of industrial scale and business environment through analysis of various industrial statistics, preceding research such as related literature search and (industrial/academic/R&D/government) specialist opinion investigation, and then calculating relative importance and priority of each factor(element) within each layer. And for raising usefulness and availability of the research result by concretely suggesting the vision, strategies, core tasks and detailed projects in which the research model and deduced result are reflected.

• Journal of KIISE:Databases
• /
• v.29 no.6
• /
• pp.453-463
• /
• 2002

With the prevalence of multi-dimensional data such as images, content-based retrieval of data is becoming increasingly important. To handle multi-dimensional data, multi-dimensional index structures such as the R-tree, Rr-tree, TV-tree, and MVP-tree have been proposed. Numerous research results on how to effectively manipulate these structures have been presented during the last decade. Query processing strategies, which is important for reducing the processing time, is one such area of research. In this paper, we propose query processing algorithms for R-tree based structures. The novel aspect of these algorithms is that they make use of the notion of VP filtering, a concept borrowed from the MVP-tree. The filtering notion allows for delaying of computational overhead until absolutely necessary. By so doing, we attain considerable performance benefits while paying insignificant overhead during the construction of the index structure. We implemented our algorithms and carried out experiments to demonstrate the capability and usefulness of our method. Both for range query and incremental query, for all dimensional index trees, the response time using VP filtering was always shorter than without VP filtering. We quantitatively showed that VP filtering is closely related with the response time of the query.