• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.4
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• pp.81-93
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• 2000

In a methodological approach to improve the processing performance of modulo exponentiation which is the primary arithmetic in RSA crypto algorithm, we present a new RSA hardware architecture based on high-radix modulo multiplication and CRT(Chinese Remainder Theorem). By implementing the modulo multiplier using radix-16 arithmetic, we reduced the number of PE(Processing Element)s by quarter comparing to the binary arithmetic scheme. This leads to having the number of clock cycles and the delay of pipelining flip-flops be reduced by quarter respectively. Because the receiver knows p and q, factors of N, it is possible to apply the CRT to the decryption process. To use CRT, we made two s/2-bit multipliers operating in parallel at decryption, which accomplished 4 times faster performance than when not using the CRT. In encryption phase, the two s/2-bit multipliers can be connected to make a s-bit linear multiplier for the s-bit arithmetic operation. We limited the encryption exponent size up to 17-bit to maintain high speed, We implemented a linear array modulo multiplier by projecting horizontally the DG of Montgomery algorithm. The H/W proposed here performs encryption with 15Mbps bit-rate and decryption with 1.22Mbps, when estimated with reference to Samsung 0.5um CMOS Standard Cell Library, which is the fastest among the publications at present.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.47-54
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• 2020

A brittle fracture is one of the source of structural damage and can bring a fatal accident. The inner shell of LNG storage tank should be designed and applied to construction by ensure that no brittle crack will occur under -162℃ condition. In point of view of fracture mechanics brittle fracture in the structure could be referred as crack initiation and crack arrest. It should be designed no crack initiation. However, in the unlikely event of a brittle fracture occurring, a back-up function of arresting the brittle crack should be included for the design. In this paper investigated the characteristics of 9% Ni steel thick plates of having a capability of arresting brittle cracks under the thickness of 33 mm, 37mm, 40 mm. First, charpy test has performed to evaluate the fundamental brittle impact fracture property of 9% Ni steel under the temperature of 24℃, -162℃ and -196℃. In addition, Duplex ESSO tests were also performed under -196℃ to evaluate the capability of crack arrest for 9% Ni steel. From the experiments results, it was confirmed that all the thickness of 9% Ni steel plates exhibits sufficient brittle crack arrest fracture toughness for the application of LNG storage tank as a inner shell.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.135-149
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• 2021

Purpose - I analyzes risk-to-performance evaluated in the market using data from sale and lease back. Specifically, I analyze from the perspective of financial institutions that purchase sale and lease back based on the cases of investment by ship investment companies and acquisition of ships. Design/methodology/approach - I use 49 sale and lease back data from 2017 to 2019 for empirical analysis. Findings - The main results of this paper are as follows. First, after sale and lease back of domestic ships, the average amount of sales by the leased shipping company is 25.1 billion won, the average amount of investment by the purchased financial institution is 14.6 billion won (60%) and the average length of the ship is nine years. In ship finance, sale and lease back is deemed to be appropriately used as a means of restructuring for a large amount of money. Second, the main risk factor for sale and lease back of domestic ships is credit risk and can be measured in VaR in practice. As a result of the empirical analysis, the average credit risk burden ratio is 9%. As a major risk factor, low creditworthiness of restructuring companies is the key. Third, as a result of measuring the profitability of financial institutions that purchase sale and lease back of domestic ships at a net current price, it has an average value of 300 million won, but the deviation by case is very large. Fourth, the risk adjusted performance of sale and lease back of domestic ships is 0.54 on average compared to the total risk capital, and 0.52 compared to the stock-risk capital, and as with profitability earlier, the deviation of each case is very large and misaligned. In order to boost the sale and lease back market for large and long-term assets, in order to overcome low profitability as a prerequisite for future participation of commercial purchased financial institutions, it is expected that purchase decisions based on expectations versus risk will be necessary. Research implications or Originality - The results of this paper are expected to broaden the understanding of sale and lease back and foster the ability to assess long-term risk and performance. Based on this, it is believed that rapid restructuring of companies through sale and lease back of large amounts of long-term assets will greatly increase the utility of the domestic financial market.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.445-453
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• 2021

CT scan is reported to have a high risk of cancer due to a relatively high dose among medical radiological examinations. In particular, exposure to radiation to the breast, which is sensitive to radiation, is inevitable during a chest CT scan for female patient. In this study, the dose reduction effect of wearing a compression band during chest CT scans in women was evaluated, and the lifetime attributable risk due to the effective dose exposed during the CT scan was estimated. As a result, when the compression band was used, the effective tube current decreased as the outer perimeter of the chest became smaller, and it was analyzed that the CT dose index and effective dose were also reduced. In addition, the lifetime attributable risk by chest CT scan was found to reduce the cancer risk by 3.2 per 100,000 for all cancers, 0.2 per 100,000 for solid cancer, and 0.8 per 100,000 for breast cancer, based on women in their 30s when using a compression band. It is judged that the risk of cancer can be reduced through the use of appropriate scan parameters and dose optimization measures such as compression bands for future CT examinations.

• Journal of Korea Foundry Society
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• v.41 no.6
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• pp.505-515
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• 2021

Creep properties of directionally solidified Ni-based superalloy CM247LC under various temperature and stress conditions have been investigated. In the heat-treated specimen, some portion of eutectic γ-γ' remained, and uniform cubic γ' was observed in the dendrites. At low temperature (750℃) and high stress condition, a large amount of deformation occurred during the primary creep, while the tertiary creep region accounted for most of the creep deformation under high temperature and low stress condition. γ' particles are sheared by dislocation dissociated into super lattice partial dislocations separated by stacking faults at 750℃. No stacking faults in γ' were found at and above 850℃ due to the temperature dependence of the stacking fault energy. Raft structure of γ' was found after creep test at high temperature of 950℃ and 1000℃. At 850℃, the deformation mechanism was shown to be dependent on the stress condition, and so rafting was observed only under low stress condition.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.319-325
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• 2022

The Study In order to obtain a sharpness Image from Skull PA axial projection (Haas) in a head axial X-ray Examination, this study changed the posture angle using Skull Phantom and evaluated the image subjectively to 5 radiologists who worked in the Department of Imaging at University Hospital. In the prone position, the head was lowered 4 cm from the back of the head, entered 25° toward the head, and the image evaluation score was high with 20 points, such as the back bone, dorsum sellae projected in the large hole, and posterior clinoid process. In addition, the score significance was verified, and the Cronbach Alpha value was evaluated to have good reliability of 0.789. As a result of calculating the signal-to-noise ratio (SNR) by setting the region of interest (ROI) of the image, it was the highest at 5.957 for 25° incident at the back of the head and 6.430 for 30° incident at the back of the head. As a result of the study, in order to obtain a sharp image of the back of the head bone, dorsum sellae, and posterior clinoid process when shooting in the axial direction after the head, it is filmed by tilting 25° toward the head from 4 cm below the back of the head. In order to obtain a sharp image of rock pyramid symmetry, petrous ridge, sagittal suture, and lambdoid suture, it is thought that it will be helpful for clinical use if you shoot it 8cm down from the back of the head and tilt it 30° toward the head.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.197-210
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• 2022

Entomopathogenic fungi can be used to control a variety of sucking and chewing insects, with little effect on beneficial insects and natural enemies. Approximately 170 entomopathogenic fungal insecticides have been registered and used worldwide, with the recent focus being on the mode of action and mechanism of insect-fungal interactions. During the initial period of research and development, the industrialization of entomopathogenic fungi focused on the selection of strains with high virulence. However, improvement in productivity, including securing resistance to environmental stressors, is a major issue that needs to be solved. Although conidia are the primary application propagules, efforts are being made to overcome the limitations of blastospores to improve the economic feasibility of the production procedure. Fungal transformation is also being conducted to enhance insecticidal activity, and molecular biology is being used to investigate functions of various genes. In the fungi-based pest management market, global companies are setting up cooperative platforms with specialized biological companies in the form of M&As or partnerships with the aim of implementing a tank-mix strategy by combining chemical pesticides and entomopathogenic fungi. In this regard, understanding insect ecology in the field helps in providing more effective fungal applications in pest management, which can be used complementary to chemicals. In the future, when fungal applications are combined with digital farming technology, above-ground applications to control leaf-dwelling pests will be more effective. Therefore, for practical industrialization, it is necessary to secure clear research data on intellectual property rights.

• Journal of the Korean Chemical Society
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• v.65 no.4
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• pp.268-278
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• 2021

The purpose of this study is to subdivide responsive teaching types proposed in the previous study in order to observe the change in the responsive teaching types in teacher educational programs, and to identify factors that impede changes in responsive teaching types. To this end, an educational program including introduction of responsive teaching, case analysis of responsive teaching, individual assignments and group discussions on facilitator type educational scenarios is provided for chemistry teachers who participated in a chemistry education course established in a graduate school of education. Based on previous research, when the teacher's teaching method was analyzed as evaluator, transfer, guide and facilitatore, a type that could not be classified was observed. In this study, responsive teaching types were added by adding two types: explorer and interpreter. In addition, through individual assignments and group discussion data, we could observe the factors that hinder teachers' responsive teaching changes. The obstacles that impede the change to responsive teaching were classified into teacher factors, student factors, and environmental factors. Among the obstacles, teacher factors include a belief in teacher-led instruction, a belief in the role of a teacher as a transfer of knowledge, a belief that the curriculum should be followed, a lack of understanding of the teacher about students, and a lack of the teacher's ability to lead student-led expansion. The student factor was distrust of the student's competence. Also, as an environmental factor, there was an educational environment such as multi-students class. Effective teacher education on responsive teaching can be achieved only when the perception related to these obstacles can be removed.

• Journal of Life Science
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• v.32 no.5
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• pp.375-390
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• 2022

Influenza viruses are zoonotic respiratory pathogens, and influenza infections have caused a substantial burden on public health systems and the livestock industry. Although currently approved seasonal influenza vaccines have shown potent protection efficacy against antigenically well-matched strains, there are considerable unmet needs for the efficient control of viral infections. Enormous efforts have been made to develop broadly protective universal influenza vaccines to tackle the huge levels of genetic diversity and variability of influenza viruses. In addition, antiviral drugs have been considered important interventions for the treatment of viral infections. The viral neuraminidase inhibitor oseltamivir is the most widely used antiviral medication to treat influenza A and influenza B viruses. However, unsatisfactory clinical outcomes resulting from side effects and the emergence of resistant variants have led to greater attention being paid to plants as a natural resource for anti-influenza drugs. In particular, the recent COVID-19 pandemic has underpinned the need for safe and effective antiviral drugs with a broad spectrum of antiviral activity to prevent the rapid spread of viruses among humans. This review outlines the results of the antiviral activities of various natural products isolated from plants against influenza viruses. Special focus is paid to the virucidal effects and the immune-enhancing effects of antiviral natural products, since the products have broad applications as inactivating agents for the preparation of inactivated vaccines and vaccine adjuvants.

• Journal of Korean Clinical Nursing Research
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• v.28 no.3
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• pp.223-232
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• 2022

Purpose: The purpose of this study was to apply patient-engaged bedside handoffs in comprehensive care units, and to evaluate the effects of bedsides to nurses and patients. Methods: This study employed a cluster randomized cross-over design.Electrical Medical Record (EMR)-based handoffs and patient-engaged bedside handoffs were alternatively applied to 104 patients, who were assigned to a total of 30 clusters (nursing handoff teams) in 4 comprehensive care units at the S medical center in Seoul, and the patients evaluated each type of handoffs. A total of 139 nurses were also participated in the same units and evaluated each type of handoffs. Data were analyzed using t-test, Wilcoxon rank sum test, ANOVA, and Kruskal-Walls test. Results: The patient's satisfaction of the patient-engaged bedside handoffs was higher than that of the EMR-based handoffs (Z=-5.16, p<.001). On the other hand, the nurse's satisfaction of the patient-engaged bedside handoffs was significantly lower than that of the EMR-based handoffs (t=13.21, p<.001). There were no differences in length of the reporting time between two types of handoffs (t=-0.48, p=.634). Conclusion: Patient satisfaction with the patient-engaged bedside handoffs was higher than that of EMR-based handoffs, and nurses' satisfaction with the patient-engaged bedside handoffs was significantly lower than that of EMR-based handoffs. Future studies are needed regarding the impacts of patient-engaged bedside handoffs on the quality of healthcare by identifying the benefits of the handoffs.