• Title/Summary/Keyword: regional image

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Neural network with occlusion-resistant and reduced parameters in stereo images (스테레오 영상에서 폐색에 강인하고 축소된 파라미터를 갖는 신경망)

  • Kwang-Yeob Lee;Young-Min Jeon;Jun-Mo Jeong
    • Journal of IKEEE
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    • v.28 no.1
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    • pp.65-71
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    • 2024
  • This paper proposes a neural network that can reduce the number of parameters while reducing matching errors in occluded regions to increase the accuracy of depth maps in stereo matching. Stereo matching-based object recognition is utilized in many fields to more accurately recognize situations using images. When there are many objects in a complex image, an occluded area is generated due to overlap between objects and occlusion by background, thereby lowering the accuracy of the depth map. To solve this problem, existing research methods that create context information and combine it with the cost volume or RoIselect in the occluded area increase the complexity of neural networks, making it difficult to learn and expensive to implement. In this paper, we create a depthwise seperable neural network that enhances regional feature extraction before cost volume generation, reducing the number of parameters and proposing a neural network that is robust to occlusion errors. Compared to PSMNet, the proposed neural network reduced the number of parameters by 30%, improving 5.3% in color error and 3.6% in test loss.

Evaluation and Prediction of Post-Hepatectomy Liver Failure Using Imaging Techniques: Value of Gadoxetic Acid-Enhanced Magnetic Resonance Imaging

  • Keitaro Sofue;Ryuji Shimada;Eisuke Ueshima;Shohei Komatsu;Takeru Yamaguchi;Shinji Yabe;Yoshiko Ueno;Masatoshi Hori;Takamichi Murakami
    • Korean Journal of Radiology
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    • v.25 no.1
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    • pp.24-32
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    • 2024
  • Despite improvements in operative techniques and perioperative care, post-hepatectomy liver failure (PHLF) remains the most serious cause of morbidity and mortality after surgery, and several risk factors have been identified to predict PHLF. Although volumetric assessment using imaging contributes to surgical simulation by estimating the function of future liver remnants in predicting PHLF, liver function is assumed to be homogeneous throughout the liver. The combination of volumetric and functional analyses may be more useful for an accurate evaluation of liver function and prediction of PHLF than only volumetric analysis. Gadoxetic acid is a hepatocyte-specific magnetic resonance (MR) contrast agent that is taken up by hepatocytes via the OATP1 transporter after intravenous administration. Gadoxetic acid-enhanced MR imaging (MRI) offers information regarding both global and regional functions, leading to a more precise evaluation even in cases with heterogeneous liver function. Various indices, including signal intensity-based methods and MR relaxometry, have been proposed for the estimation of liver function and prediction of PHLF using gadoxetic acid-enhanced MRI. Recent developments in MR techniques, including high-resolution hepatobiliary phase images using deep learning image reconstruction and whole-liver T1 map acquisition, have enabled a more detailed and accurate estimation of liver function in gadoxetic acid-enhanced MRI.

Evaluation of Zone 2 Thoracic Endovascular Aortic Repair Performed with and without Prophylactic Embolization of the Left Subclavian Artery in Patients with Traumatic Aortic Injury

  • Miju Bae;Chang Ho Jeon;Hoon Kwon;Jin Hyeok Kim;Seon Uoo Choi;Seunghwan Song
    • Korean Journal of Radiology
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    • v.22 no.4
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    • pp.577-583
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    • 2021
  • Objective: To report the authors' experience in performing thoracic endovascular aortic repair (TEVAR) for zone 2 lesions after traumatic aortic injury (TAI). Materials and Methods: This retrospective review included 10 patients who underwent zone 2 TEVAR after identification of aortic isthmus injury by CT angiography (CTA) upon arrival at the emergency room of a regional trauma center from 2016 to 2019. Patients were classified into two groups: those who underwent left subclavian artery (LSA) embolization concurrently with the main TEVAR procedure, and those in whom LSA embolization was not performed during the main procedure, but was planned as a bailout treatment if type II endoleak was noted on follow-up CTA images. Pre-procedural and procedure-related factors and post-procedure prognosis were compared between the groups. Results: There were no differences in pre-procedural factors, occurrence of endoleaks, and post-procedure prognosis (including mortality) between patients in the two groups. The duration of the procedure was shorter in the non-LSA embolization group (61 minutes vs. 27 minutes, p = 0.012). During follow-up, type II endoleak did not occur in either group. Conclusion: Delaying preventative LSA embolization until stabilization of the patient would be desirable when performing zone 2 TEVAR for TAI, in the absence of endoleak on the completion aortography image taken after complete deployment of the stent graft.

The Roles of Shop Owners in Boosting Conventional Markets (상권활성화에 있어서 상업자의 역할에 관한 연구)

  • Park, Seung-Je
    • Journal of Distribution Science
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    • v.9 no.4
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    • pp.93-102
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    • 2011
  • With the increasing interest in boosting conventional markets, many authors have paid considerable attention to the roles of shop owners, store image improvement, and how to attract or maintain customers. Nevertheless, it is not easy to find papers related to the relationship between shop owners and their contribution to trading areas, directly or indirectly, in the academic world. Accordingly, research for answering the following question has been initiated: what kind of roles do shopkeepers should play in revitalizing poor conventional markets? Based on the previous studies focusing on enhancing traditional markets, this research was approached from the new insights that have been obtained concerning how to boost conventional markets, that is, from the perspectives of a shop owner and a trader. Therefore, this research aims at identifying some resolutions associated with the roles of shop owners to enhance a shopping district in a specific area, classifying their business roles into a few categories, depending on the degree of their participation in improving the shopping environment. Compared with previous studies focusing on emphasizing the importance of improving customer services from a shopkeeper's perspective, this research provides a new insight as far as how to boost conventional markets. It is, furthermore, necessary to note how market participants, particularly shop owners as they are the key players, can contribute to rebuilding their business area together with their customers. As a research technique for effectively achieving the research goal, the authors adopted a documentation methodology based on a large amount of the existing literature for studying how to rebuild traditional markets. Concerned about the ways to revitalize conventional markets, many authors have proposed a variety of strategies, and have suggested more detailed action plans from a practitioner's perspective. By analyzing these research results, the authors will have accomplished the research aim. Rather than simply identifying the roles of shop owners, the author found that they had to understand their social contribution for enhancing their trading areas, as well as their functional roles, in forming a regional society. The conventional market should be, thus, regarded as the place to share regional culture. Consequently, the authors draw some conclusions from the research results. In order to answer the above question, it was found that the roles of shop owners have been considered as one of the most important ways for revitalizing traditional markets. With respect to their roles, it is evident that their business activities are closely related to the improvement of the trading area in terms of sociality, regional development, and market revitalization, by selling products or services to the customers visiting that area. In a word, this implies that shop owners have to actively take part in boosting conventional markets as a core player. Although the authors have properly achieved the research aim, this study has a limitation, like most other research, in adopting a documentation method. Because the research is based on existing data results provided by the prior research conducted a long time ago, whether the research findings are applicable in a contemporary market should be re-examined in future research from a practitioner's perspective, rather than from an academic's perspective.

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Clinical Significance of Reverse Redistribution Phenomenon on Delayed Tc-99m Tetrofosmin Myocardial Perfusion Imaging in Patients with Acute Myocardial Infarction (급성 심근경색 환자의 Tc-99m Tetrofosmin 심근 관류 지연영상에서 관찰되는 역재분포 현상의 임상적 의의)

  • Park, Soon-Ah;Kim, Dae-Weung;Kim, Chang-Guhn;Jeong, Jin-Won;Kim, Nam-Ho;Yun, Kyeong-Ho
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.2
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    • pp.112-119
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    • 2009
  • Purpose: This study was performed to investigate the clinical significance of reverse redistribution(RR) phenomenon detected on delayed Tc-99m tetrofosmin myocardial single photon emission computed tomography(SPEG) in patients with acute myocardial infarction after revascularization. Materials and Methods: A Tc-99m tetrofrosmin myocardial SPECT was performed in 67 consecutive patients after revascularization for acute myocardial infarction. Myocardial SPECT imaging was performed for early imaging at 40 min and for delayed imaging at 180 min after reinjection at myocardial stress. Regional myocardial uptakes were scored by 4-point scoring in the left ventricular wall divided into 17 segments. Reverse redistribution was defined as an increase of more than 2 point in the activity score on the delayed image. Follow-up myocardial SPECT and coronary angiography(CAG) were performed 9 months later. Results: On myocardial SPECT performed following revascularization, RR was observed in 100 of all 319 segments(31%) and in 43 patients(64%). The abnormalities of perfusion and regional wall motion were more severe in the patients with RR compared to those without RR(p<0.05). On follow-up myocardial SPECT, the myocardial perfusion, regional wall motion, and myocardial thickness were significantly improved in the patients with RR(p<0.05) however, these changes were not significant in those without RR. There was no significant difference between the patients with RR and those without RR in the occurrence of restenosis on CAG. Conclusions: In patients with acute myocardial infarction, the regions showing the RR phenomenon on delayed Tc-99m tetrofosmin SPECT may reflect viable myocardium and indicate recovery of salvaged myocardium.

The application of photographs resources for constructive social studies (구성주의적 사회과 교육을 위한 사진자료 활용방안)

  • Lee, Ki-Bok;Hwang, Hong-Seop
    • Journal of the Korean association of regional geographers
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    • v.6 no.3
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    • pp.117-138
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    • 2000
  • This study is, from the view point of constructive social studies which is the foundation of the 7th curriculum, to explore whether there is any viable program and to investigate it by which students, using photo resources in social studies, can organize their knowledge in the way of self-directed thinking. The main results are as follows: If it is a principle of knowledge construction process of constructive social studies that individual construction (cognitive construction) develops into communal construction(social construction) and yet communal construction develops itself, interacting with individual construction, it will be meet the objectives of social studies. In social studies, photos are a powerful communication tool. communicating with photos enables to invoke not only the visual aspects but also invisible aspects of social phenomena from photos. It, therefore, can help develop thinking power through inquiry learning, which is one of the emphasis of the 7th curriculum. Having analyzed photo resources appeared on the regional textbooks in elementary social studies, they have been appeared that even though the importance and amount of space photo resources occupy per page is big with regard to total resources, most of the photos failed to lad to self-directed thinking but just assistant material in stead. Besides, there appeared some problems with the title, variety, size, position, tone of color, visibility of the photos, and further with the combination of the photos. Developing of photo resources for constructive social studies is to overcome some problems inherent in current text books and to reflect the theoretical background of the 7th curriculum. To develop the sort of photo that can realize the point just mentioned, it would be highly preferable to provide photo database to facilitate study with homepage through web-based interaction. To take advantage of constructive photo resources, the instruction is strategized in four stages, intuition, conflict, accommodation, and equilibration stage. With the advancement of the era of image culture, curriculum developers are required to develop dynamic, multidimensional digital photos rather than static photos when develop text books.

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Principle and Recent Advances of Neuroactivation Study (신경 활성화 연구의 원리와 최근 동향)

  • Kang, Eun-Joo
    • Nuclear Medicine and Molecular Imaging
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    • v.41 no.2
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    • pp.172-180
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    • 2007
  • Among the nuclear medicine imaging methods available today, $H_2^{15}O-PET$ is most widely used by cognitive neuroscientists to examine regional brain function via the measurement of regional cerebral blood flow (rCBF). The short half-life of the radioactively labeled probe, $^{15}O$, often allows repeated measures from the same subjects in many different task conditions. $H_2^{15}O-$ PET, however, has technical limitations relative to other methods of functional neuroimaging, e.g., fMRI, including relatively poor time and spatial resolutions, and, frequently, insufficient statistical power for analysis of individual subjects. However, recent technical developments, such as the 3-D acquisition method provide relatively good image quality with a smaller radioactive dosage, which in turn results in more PET scans from each individual, thus providing sufficient statistical power for the analysis of individual subject's data. Furthermore, the noise free scanner environment $H_2^{15}O$ PET, along with discrete acquisition of data for each task condition, are important advantages of PET over other functional imaging methods regarding studying state-dependent changes in brain activity. This review presents both the limitations and advantages of $^{15}O-PET$, and outlines the design of efficient PET protocols, using examples of recent PET studies both in the normal healthy population, and in the clinical population.

Developments of Local Festival Mobile Application and Data Analysis System Applying Beacon (비콘을 활용한 위치기반 지역축제 모바일 애플리케이션과 데이터 분석 시스템 개발)

  • Kim, Song I;Kim, Won Pyo;Jeong, Chul
    • Korea Science and Art Forum
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    • v.31
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    • pp.21-32
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    • 2017
  • Local festivals form the regional cultures and atmosphere of communication; they increase the demand of domestic tourism businesses and thus, have an important role in ripple effects (e.g. regional image improvement, tourist influx, job creation, regional contents development, and local product sales) and economic revitalization. IoT (Internet of Thing) technologies have been developed especially, beacon-one of the IoT services has been applied as plenty of types and forms both domestically and internationally. However, notwithstanding expansion of current digital mobile technologies, it still remains as difficult for the individual to track the information about all the local festivals and to fulfill the tourists' needs of enjoying festivals given the weak strategic approaches and advertisement activities. Furthermore, current festival-related mobile applications don't function well as delivering information and have numerous contents issues (e.g. ways of information delivery within the festival places, independent application usage for each festival, one time usage due to one time event). This research, based on the background mentioned above, aims to develop the local festival mobile application and data analysis system applying beacon technology. First of all, three algorithms were developed, namely, 'festival crowding algorithm', 'visitor stats algorithm', and 'customized information algorithm', and then beta test was followed with the developed application and data analysis system. As a result, they could form the database of visitors' types and behaviors, and provide functions and services, such as personalized information, waiting time for festival contents, and 'hot place' function. Besides, in Google Play store, they also got the titles given with more than 13,000 downloads within first three months and as the most exposed application related with festivals; and, thus, got credited with their marketability and excellence. This research follows this order: chapter 2 shows the literature review of local festival related with technology development, beacon service, and festival application. In Chapter 3, design plans and conditions are described of developing local festival mobile application and data analysis system with beacon. Chapter 4 evaluates the results of the beta performance test to verify applicability of the developed application and data analysis system, and lastly, chapter 5 explains the conclusion and suggests the future research.

Comparison of Algorithms for Generating Parametric Image of Cerebral Blood Flow Using ${H_2}^{15}O$ PET Positron Emission Tomography (${H_2}^{15}O$ PET을 이용한 뇌혈류 파라메트릭 영상 구성을 위한 알고리즘 비교)

  • Lee, Jae-Sung;Lee, Dong-Soo;Park, Kwang-Suk;Chung, June-Key;Lee, Myung-Chul
    • The Korean Journal of Nuclear Medicine
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    • v.37 no.5
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    • pp.288-300
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    • 2003
  • Purpose: To obtain regional blood flow and tissue-blood partition coefficient with time-activity curves from ${H_2}^{15}O$ PET, fitting of some parameters in the Kety model is conventionally accomplished by nonlinear least squares (NLS) analysis. However, NLS requires considerable compuation time then is impractical for pixel-by-pixel analysis to generate parametric images of these parameters. In this study, we investigated several fast parameter estimation methods for the parametric image generation and compared their statistical reliability and computational efficiency. Materials and Methods: These methods included linear least squres (LLS), linear weighted least squares (LWLS), linear generalized least squares (GLS), linear generalized weighted least squares (GWLS), weighted Integration (WI), and model-based clustering method (CAKS). ${H_2}^{15}O$ dynamic brain PET with Poisson noise component was simulated using numerical Zubal brain phantom. Error and bias in the estimation of rCBF and partition coefficient, and computation time in various noise environments was estimated and compared. In audition, parametric images from ${H_2}^{15}O$ dynamic brain PET data peformed on 16 healthy volunteers under various physiological conditions was compared to examine the utility of these methods for real human data. Results: These fast algorithms produced parametric images with similar image qualify and statistical reliability. When CAKS and LLS methods were used combinedly, computation time was significantly reduced and less than 30 seconds for $128{\times}128{\times}46$ images on Pentium III processor. Conclusion: Parametric images of rCBF and partition coefficient with good statistical properties can be generated with short computation time which is acceptable in clinical situation.

A Study on the Quality Improvement of Brain Perfusion SPECT Image (뇌혈류 단일광자방출단층촬영 영상 품질 향상에 대한 연구)

  • Kil, Sang-Hyeong;Lim, Yung-Hyun;Park, Gwang-Yeol;Cho, Seong-Mook
    • The Korean Journal of Nuclear Medicine Technology
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    • v.23 no.2
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    • pp.13-19
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    • 2019
  • Purpose Tc-99m HMPAO is widely used radiopharmaceutical for brain perfusion SPECT. Tc-99m HMPAO is chemically unstable and is liable to show deterioration of labeling efficiency due to high incidence of secondary Tc-99m HMPAO complex, free pertechnetate and reduced-hydrolyzed Tc-99m. In this study, we investigated whether sialogogues administration could reduce the impurities of Tc-99m HMPAO. Materials and Methods In thirty subjects(20 male and 10 female, age range 19~89 years, mean age $60.7{\pm}14.5years$), brain perfusion SPECT were performed at basal and citric acid stimulation states consecutively after injection of 555 MBq of Tc-99m HMPAO. In the salivary glands, the uptake coefficient was calculated using Siemens processing program. Statistical comparison between before and after the citric acid stimulation performed paired t-test. P value less than 0.05 was regarded as statistically significant. Results Salivary glands uptake was $12900{\pm}3101$ counts in basal and $10677{\pm}2742$ counts in citric acid stimulation states. Unnecessary impurities in the body is much decreased after citric acid administration(t=10.78, P<0.05). The image quality was much improved after administration of citric acid and the regional cerebral perfusion was clearly from demarcated the background. Conclusion The impurity is distributed throughout the body particularly in the salivary glands and nasal mucosa when Tc-99m HMPAO brain perfusion SPECT is performed. If this impurities is not removed, the quality of the image may deteriorate, resulting in errors in visual evaluation. The use of sialogogues could be helpful for decreasing unnecessary impurities in the body.