• Journal of Digital Convergence
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• v.13 no.9
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• pp.489-495
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• 2015

Image availability evaluated by the degree of agreement and sensitive using the process improve visualization according to the Algorithm modification in Image Post-Processing. Reliability measured by the Breast Imaging Reporting and Data System. 172 patients visit same period divided by BI-RADS, category five stages, and contents of breast parenchyma into Calcification, Nodule and Mass. Evaluated the TE/PV image reliability, visualization sensitive, agreement of diagnosis. Convergence analysis was an in various fields. According to the result of this research, PV has higher sensitive and accuracy about lesions than TE visual and there is a difference insensitive by contents of breast parenchyma. Therefore, practical use of Algorithm Modification(Tissue Equalization: TE, Premium View: PV) is expected to improve more accurate, useful diagnosis, which has not been easy until now.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.1
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• pp.27-34
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• 2020

Human access is restricted to environment where radiation sources are used, however observation equipment should be radiation-resistant as it is exposed. Therefore, if tungsten with the highest specific gravity and melting point and the lowest lead were selected to reduce the dose to the Cobalt 60 radiation source to 1/8, Tu had a volume of 432.6cm3, a thickness of 2.4cm, and Pb had a volume of 961cm3,, a thickness of 3.6cm. By applying this method, produced a radiation resistant CMOS camera with a camera module using a CMOS Image sensor and a radiation shielding structured housing. As a result of applying the head detachable 2M AHD camera (No. ①) that survived the experiment to select the optimal shielding thickness, when shielding the associated equipment such as cameras, adapters, etc. is achieved, it was confirmed that the design of the structure is appropriate by operating well at doses higher than 1.88×106rad. Therefore, it is expected to secure the camera technology and business feasibility that can be applied to high radiation environments.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.517-526
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• 2023

To avoid arbitrary design and excessive braces of system supports with high reusability in the field, this study aimed to propose connection conditions for the vertical and horizontal joints of the system supports based on performance evaluation. Disk-type and pocket-type connection materials, widely used in domestic construction sites, were selected for evaluation of rotational stiffness based on load directions(vertical and horizontal) and loading methods (monotonic and cyclic). Contrary to the current design standards specifying a rotational stiffness of "0" for connection materials, the experimental results revealed that, contrary to the current design standards specifying a rotational stiffness of "0" for connection materials, all specimens exhibited rotational stiffness values. The maximum rotational stiffness was observed to be 19.624 kNm/rad in specimens subjected to repeated loading in the vertical direction using disk-type connection materials.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.3-14
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• 2023

Breast Imaging Reporting and Data System (BI-RADS) is a communication and data tracking system that standardizes and controls the quality of reporting by presenting lexicon descriptors, assessment categories, and recommendations for managing breast lesions. Using standardized terminology recommended by BI-RADS, radiologists can concisely and reproducibly communicate breast imaging results to clinicians. They can also provide the estimated malignant probability of the lesions found and guide management for them by determining the final assessment category. The limitations of BI-RADS 5th edition currently in use are that there are some areas for which standardized terminologies still need to be established, and that the diagnostic criteria of MRI assessment categories 3 and 4 are ambiguous compared to those for mammography or ultrasound. The next revision of BI-RADS is expected to include solutions for overcoming current limitations.

• Journal of Space Technology and Applications
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• v.4 no.3
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• pp.232-243
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• 2024

In order to perform various missions in space, including planetary exploration, estimating the position of a satellite in orbit is a very important factor because it is directly related to the success rate of mission performance. As a study for autonomous satellite navigation, this study estimated the satellite's attitude and real time orbital position using a star sensor algorithm with two star trackers and earth sensor. To implement the star sensor algorithm, a simulator was constructed and the position error of the satellite estimated through the technique presented in the paper was analyzed. Due to lens distortion and errors in the center point finding algorithm, the average attitude estimation error was at the level of 2.6 rad in the roll direction. And the position error was confirmed by attitude error, so average error in altitude direction was 516 m. It is expected that the proposed satellite attitude and position estimation technique will contribute to analyzing star sensor performance and improving position estimation accuracy.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.607-613
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• 1984

Thirty seven patients with ostium secundum atrial septal defect, operated from January, 1976 to September, 1984 at the Department of Thoracic and Cardiovascular Surgery, Kyungpook National University Hospital, were given clinical assessment. The following results were obtained. 1.Ostium secundum atrial septal defect was comprised of 18% of congenital heart disease. Their mean age was 15.7\ulcorner.42. Sex ratio [male:female] was 1:1.1. 2.Most frequent clinical symptom was dyspnea on exertion occurred in 26 patients [76.5%]. Only one patient had no symptom [2.9%]. 3.Pre-operative EKG findings revealed RVH in 61.8%, ICRBBB in 29.4%, and RAD in 41.2%. 4.Mean value of systolic pulmonary arterial pressure in patients over 20 years old was 37.8\ulcorner4.4mmHg and it was 28.1\ulcorner10.2mmHg in patients under 20 years old, but the difference between two groups was not statistically significant. 5. In large defect group [>3cm in diameter], Qp/Qs was significantly increased than small defect group [<3cm in diameter], but systolic pulmonary arterial pressure and Rp/Rs were not different between two groups. 6. Overall operative mortality was 5.4%.

• Journal of Radiation Protection and Research
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• v.10 no.2
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• pp.137-143
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• 1985

To study the relationships among the frequency of chromosomal aberration induced by radiation, mouse age at the time of exposure and elapsed time after the irradiation, the 40, 150 and 300 day old mice were irradiated by gamma rays to 200 rad of acute whole body doses. The bone marrow chromosomes were observed in 8 experimental groups such as 1, 2, 3, 4, 8, 16, 30, 60 and 90 days after irradiation. In the 40 day old mice the frequencies of cell with chromosomal aberration were 53.0%, 21.5%, 8.4%, 8.4%, 12.0%, 8.0%, 7.0% and 5.0% in 8 experimental groups, in the 150 day old mice 32.5%, 12.1%, 10.5%, 12.8%, 0.03%, 9.7%, 7.0% and 4.2%. The 300 day old mice showed that the frequencies of cells with chromosomal aberration were 27.7%, 13.6%, 9.0%, 9.3%, 13.3%, 14.4%, 7.5% and 9.5% in each experimental group. There were tendencies that the frequencies of cell with chromosomal aberration were higher in the young mice than the old ones within 2 days after the irradiation but in the old mice than the young ones after 4 days.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.3
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• pp.269-274
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• 2002

statement of problem The viscoelastic property is the most important and peculiar characteristics of soft liners. But the authorized standard is not certainly established than other dental materials. purpose of study This study is aimed to compare the initial flow of gelation of the modified soft liner with 4-META with that of PMMA soft liners using dynamic method and evaluate the clinical acceptance of the trial materials. materials and method This study consists of 3 groups with the given % of 4-META powder in the Coe soft liquid; 0%, 5%, 10% Each group was tested for 10 times to record the change of G′values during 3 hours. the gelation time was recorded by the oscillating rheometer with parallel plate with 1 rad/sec. results As the results of this study, the gelation time of modified soft liner was elongated by 5 to 6 minutes. conclusion The mean gelation time of modified soft liner could be within the range of clinically acceptable.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.4
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• pp.361-367
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• 2014

Ultra-precision positioning plays a crucial role in emerging technologies such as electronics, bioengineering, optics, and various nanofabrication technologies. As a result, various nanopositioning methods have been presented. In particular, nanopositioning using a flexure mechanism and piezo-electric actuator is one of the most valuable methods because of its friction-free motion and subnanometer-scale motion resolution. In this study, a rotational nanoactuator based on a right-circular flexure mechanism and piezo-electric actuator was developed through a consideration of the kinematics and structural deformation. An experimental setup was constructed to verify the performance expectation. Consequently, it was demonstrated that the developed system had a maximum rotational angle of about 0.01 rad, as well as sufficient linearity with respect to the input voltage.

• Journal of Radiation Protection and Research
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• v.9 no.2
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• pp.67-75
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• 1984

As a part of studies on acute effects of high dose irradiation the present report was carried out to evaluate the changes of the leukocyte life span in the Newzealand white male rabbits by a single whole body exposure to gamma rays from $^{60}Co$ teleirradiation unit. The exposure was done in dose levels of 100, 300, 550 and 1,000 rad to each experimental group of 10 rabbits. The life span and apparent half survival time of leukocytes, and the elution rate of leukocytes in the circulating blood were measured by McMillan method using $^{51}Cr$. 1. As a critical indicator of radiation hazards of the Newzealand male rabbits, the LD 50/30 and LD 100/30 after whole body exposure was estimated as 550 and 1,000 rads respectively. 2. The life span of leukocyte in the circulation after irradiation was slightly shortened in the 100 rad irradiated group, as compared with the unirradiated control group, but markedly shortened in the 300, 550 and 1,000 rads irradiated group. 3. After irradiation, decrease of leukocyte half survival time in the circulation showed the same pattern as that of leukocytes life span. 4. As the irradiation doses increased, the elution rate of $^{51}Cr$ loss from $^{51}Cr$ tagged leukocytes in the circulation were markedly increased gradually. 5. The life span shortening of leukocytes in the circulation after irradiation seems to occure by two processes of senescence acceleration and early destruction.