• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.401-410
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• 2003

This study investigates the biomechanical efficacies of various cement augmentation techniques with or without pressurization for varying degrees of osteoporotic femur. For this study, a biomechanical analysis using a finite element method (FEM) was undertaken to evaluate surgical procedures, Simulated models include the non-cemented(i.e., hip screw only, Type I), the cement-augmented(Type II), and the cemented augmented with pressurization(Type III) models. To simulate the fracture plane and other interfacial regions, 3-D contact elements were used with appropriate friction coefficients. Material properties of the cancellous bone were varied to accommodate varying degrees of osteoporosis(Singh indices, II∼V). For each model. the following items were analyzed to investigate the effect surgical procedures in relation to osteoporosis of varying degrees : (a) von Mises stress distribution within the femoral head in terms of volumetric percentages. (b) Peak von Mises stress(PVMS) within the femoral head and the surgical constructs. (c) Maximum von Mises strain(MVMS) within the femoral head, (d) micromotions at the fracture plane and at the interfacial region between surgical construct and surrounding bone. Type III showed the lowest PVMS and MVMS at the cancellous bone near the bone-construct interface regardless of bone densities. an indication of its least likelihood of construct loosening due to failure of the host bone. Particularly, its efficacy was more prominent when the bone density level was low. Micromotions at the interfacial surgical construct was lowest in Type III. followed by Type I and Type II. They were about 15-20% of other types. which suggested that pressurization was most effective in limiting the interfacial motion. Our results demonstrated the cement augmentation with hip screw could be more effective when used with pressurization technique for the treatment of intertrochanteric fractures. For patients with low bone density. its effectiveness can be more pronounced in limiting construct loosening and promoting bone union.

• Journal of the Korean earth science society
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• v.43 no.6
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• pp.691-711
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• 2022

The state-of-the-art Earth system model as a virtual Earth is required for studies of current and future climate change or climate crises. This complex numerical model can account for almost all human activities and natural phenomena affecting the atmosphere of Earth. The Unified Model (UM) from the United Kingdom Meteorological Office (UK Met Office) is among the best Earth system models as a scientific tool for studying the atmosphere. However, owing to the expansive numerical integration cost and substantial output size required to maintain the UM, individual research groups have had to rely only on supercomputers. The limitations of computer resources, especially the computer environment being blocked from outside network connections, reduce the efficiency and effectiveness of conducting research using the model, as well as improving the component codes. Therefore, this study has presented detailed guidance for installing a new version of the UM on high-performance parallel computers (Linux clusters) owned by individual researchers, which would help researchers to easily work with the UM. The numerical integration performance of the UM on Linux clusters was also evaluated for two different model resolutions, namely N96L85 (1.875° ×1.25° with 85 vertical levels up to 85 km) and N48L70 (3.75° ×2.5° with 70 vertical levels up to 80 km). The one-month integration times using 256 cores for the AMIP and CMIP simulations of N96L85 resolution were 169 and 205 min, respectively. The one-month integration time for an N48L70 AMIP run using 252 cores was 33 min. Simulated results on 2-m surface temperature and precipitation intensity were compared with ERA5 re-analysis data. The spatial distributions of the simulated results were qualitatively compared to those of ERA5 in terms of spatial distribution, despite the quantitative differences caused by different resolutions and atmosphere-ocean coupling. In conclusion, this study has confirmed that UM can be successfully installed and used in high-performance Linux clusters.

• Maritime Security
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• v.7 no.1
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• pp.31-60
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• 2023

This study proposes a new convergence weapon system that combines the covert placement and detection abilities of a self-propelled mobile mine with the rapid tracking and attack abilities of supercavitating rocket torpedoes. This innovative system has been designed to counter North Korea's new underwater weapon, 'Haeil'. The concept behind this convergence weapon system is to maximize the strengths and minimize the weaknesses of each weapon type. Self-propelled mobile mines, typically placed discreetly on the seabed or in the water, are designed to explode when a vessel or submarine passes near them. They are generally used to defend or control specific areas, like traditional sea mines, and can effectively limit enemy movement and guide them in a desired direction. The advantage that self-propelled mines have over traditional sea mines is their ability to move independently, ensuring the survivability of the platform responsible for placing the sea mines. This allows the mines to be discreetly placed even deeper into enemy lines, significantly reducing the time and cost of mine placement while ensuring the safety of the deployed platforms. However, to cause substantial damage to a target, the mine needs to detonate when the target is very close - typically within a few yards. This makes the timing of the explosion crucial. On the other hand, supercavitating rocket torpedoes are capable of traveling at groundbreaking speeds, many times faster than conventional torpedoes. This rapid movement leaves little room for the target to evade, a significant advantage. However, this comes with notable drawbacks - short range, high noise levels, and guidance issues. The high noise levels and short range is a serious disadvantage that can expose the platform that launched the torpedo. This research proposes the use of a convergence weapon system that leverages the strengths of both weapons while compensating for their weaknesses. This strategy can overcome the limitations of traditional underwater kill-chains, offering swift and precise responses. By adapting the weapon acquisition criteria from the Defense force development Service Order, the effectiveness of the proposed system was independently analyzed and proven in terms of underwater defense sustainability, survivability, and cost-efficiency. Furthermore, the utility of this system was demonstrated through simulated scenarios, revealing its potential to play a critical role in future underwater kill-chain scenarios. However, realizing this system presents significant technical challenges and requires further research.

• Journal of Chest Surgery
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• v.36 no.9
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• pp.638-645
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• 2003

The purposes of this study were to evaluate the effect of myocardial protection with our cold blood cardioplegic solution and to observe the relationship between ultrastructural study and other evaluation methods and its effectiveness. Material and Method: We evaluated the changes of myocardial ultrastructure using semi-quantitative scoring system, CK-MB fraction, SGOT and LDH1/LDH2, and EKG in 18 patients undergoing valvular heart surgery and coronary artery bypass grafting (CABG). Right atrial auricular biopsies were taken before the cardiopulmonary bypass (CPB) and shortly after the end of CPB. Myocardium-related serum enzymes ＆ EKG were checked for 3 days of postoperative period and their postoperative peak enzyme value and observed new Q wave ＆ ST segment elevation in EKG were choosen. Result: There were 8 males and 10 females, and their mean age was 55.6$\pm$13. Eight patients underwent valvular heart surgery and ten coronary artery bypass grafting, The mean CPB time was 119$\pm$29 minutes and the mean aortic cross-clamp (ACC) time was 75.4$\pm$24 minutes. Before the start of CPB, the mean mitochondrial score was 4.28$\pm$0.53 and after the end of CPB, it significantly increased to 2.35$\pm$0.79. There was no evidence of perioperative myocardial infarction in terms of myocardiumrelated serum enzyme value and Q wave and ST change in EKG. There was no significant relationship between pre-CPB and post-CPB mitochondrial score and the mean time of CPB and ACC, and the mean value of postoperative peak CK-MB, SGOT and LDH1/LDH2, but there was relatively positive correlation of CPB time with peak LDH1/LDH2. Conclusion: Despite the apparent satisfactory results in myocardium-related serum enzymes ＆ EKG, with this study using the cold blood cardioplegic solution, there were many changes in myocardial ultrastructures, and more studies are needed to obtain further information.

• Progress in Medical Physics
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• v.15 no.3
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• pp.161-166
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• 2004

A simplistic quality assurance (QA) method was designed for a Linac built-in enhanced dynamic wedge (EDW), which can be utilized to make wedged beam distributions. For the purpose of implementing the EDW symmetry QA, a film dosimetry system, low speedy dosimetry film, film densitometer and 3D RTP system were used, and the films irradiated by means of a 60$^{\circ}$ Reversed wedge pair (REWP) method. The profiles were then analyzed in terms of their symmetries, including partial treatment, which is the case of stopping it abruptly during EDW irradiation, and the measured and calculated values compared using the Cad Plan Golden Segmented Treatment Table (Golden STT). The result of this experiment was in good agreement, within 1 %, of the 'reversed wedge pair counterbalance effect'. For the QA of the effective wedge factor (EWF), the authors measured EWFs in relation to the 10$^{\circ}$, 15$^{\circ}$, 20$^{\circ}$, 25$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$ and 60$^{\circ}$ EDW, which were compared with the calculated values using the correction factor derived from the Golden STT and the log files produced automatically during the process of EDW irradiation. By means of this method it was capable of check up the safety of effective wedge factor without any other dosimetry system. The EDW QA was able to be completed within 1 hour from irradiation to analysis as a consequence of the simplified QA procedure, with maximized effectiveness. Unlike the metal wedge system, the EDW system was heavily dependent on the dose rates and jaw movements; therefore, its features could potentially cause inaccuracy. The frequent simplistic QA for the EDW is essential, and could secure against the flaw of dynamic treatment that uses the EDW.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.494-501
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• 2010

The purpose of this study was to examine the presence of Bacillus cereus, aerobic bacteria and coliforms in the raw material of infant formulas and investigate the manufacturing process in terms of microbial safety. Among ten kinds of raw infant formula material samples (n=20), Bacillus cereus appeared in two (n=4). Aerobic bacteria were not detected in raw infant formula material or maximum 4.15 log CFU/g. Eleven species of aerobic bacteria were isolated and 76% of them were Sphingomonas paucimobilis, Pseudomonas fluorescens, Rhizobium radiobactor, or Stenotrophomonas maltophilia. A Pearson's correlation analysis revealed that the most influential factors for detecting Bacillus cereus were aerobic bacteria and coliforms. In other words, when the measured values of aerobic bacteria and coliforms were higher, the possibility that Bacillus cereus would appear increased. In a regression model to predict Bacillus cereus, the rate of appearance was correlated with aerobic bacteria and coliforms, and its contribution rate for effectiveness was 86%. Improving microbial quality control by pasteurization, spray dry, popping and extrusion resulted in a decrease in the numbers of Bacillus cereus, aerobic bacteria and coliforms in the raw materials. The results suggest that a hazard analysis and critical control point system might be effective for reducing microbiological contamination.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.169-179
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• 2011

There are two types of nuclear reactors in Korea and they are PWR type and CANDU type. The safe management of the spent fuels from these reactors is very important factor to maintain the sustainable energy supply with nuclear power plant. In Korea, a reference disposal system for the spent fuels has been developed through a study on the direct disposal of the PWR and CANDU spent fuel. Recently, the research on the demonstration and the efficiency analyses of the disposal system has been performed to make the disposal system safer and more economic. PWR spent fuels which include a lot of reusable material can be considered being recycled and a study on the disposal of HLW from this recycling process is being performed. CANDU spent fuels are considered being disposed of directly in deep geological formation, since they have little reusable material. In this study, based on the Korean Reference spent fuel disposal System (KRS) which was to dispose of both PWR type and CANDU type, the more effective CANDU spent fuel disposal systems were developed. To do this, the disposal canister for CANDU spent fuels was modified to hold the storage basket for 60 bundles which is used in nuclear power plant. With these modified disposal canister concepts, the disposal concepts to meet the thermal requirement that the temperature of the buffer materials should not be over $100^{\circ}C$ were developed. These disposal concepts were reviewed and analyzed in terms of disposal effective factors which were thermal effectiveness, U-density, disposal area, excavation volume, material volume etc. and the most effective concept was proposed. The results of this study will be used in the development of various wastes disposal system together with the HLW wastes from the PWR spent fuel recycling process.

• Journal of The Korean Association For Science Education
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• v.36 no.5
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• pp.757-768
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• 2016

This study developed an SSI (Socio-Scientific Issue) discussion program that applies a creative technique called six thinking hats, and then investigated the differences in argumentation patterns and effects on the decision-making abilities of each character feature of students between SNS debate and existing face to face debate. There were three SSI themes - Designer Babies, embryonic stem cell study, and legitimacy of abortion. Students were divided into two groups, the debate group using SNS and face to face debate group. The character patterns of students were divided to 'extraversion,' 'agreeableness,' and 'conscientiousness' through test sheets for character features for each student. Both groups were educated for creative discussion methods using six thinking hats and then, the class progressed. As a result of analyzing argumentation patterns used in SNS debate and face to face debate, the most used argumentation pattern was the "cause pattern." But comparing to face to face debate, other patterns (mark, inference, authority, motive) were also used in SNS debate. The study analyzed three factors of decision-making ability for each character feature of students such as complexity, perspectives, and inquiry. As a result, for 'complexity' factor, there was a significant difference between SNS debate group and face to face debate group only in the student group of Agreeableness. For 'perspectives' factor, there were significant differences between SNS debate group and face to face debate group in all three characters. Finally, for inquiry, there were no significant differences between SNS debate group and face to face debate group in all three characters. Accordingly it would be necessary to apply SNS debate using the six thinking hats in SSI education to enhance perspectives.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.206-214
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• 2002

Purpose : The aim of this study was to assess the effectiveness, survival rate and complications of radiation therapy and chemoradiation treatment in hypopharyngeal cancer. Methods and Materials : From January 1984 to December 1999, 56 patients who had hypopharyngeal carcinoma treated with curative radiation therapy were retrospectively studied. Twenty four patients $(42.9\%)$ were treated with radiation therapy alone (Group I) and $32\;(57.1\%)$ treated with a combination of chemotherapy and radiation (Group II). Total radiation dose ranged from 40.5 to 83. 5 Gy (median 67.9 Gy). Radiotherapy was given with conventional technique in 9 patients $(16.4\%)$, with hyperfractionation I ($1.15\~1.2$ Gy/fr., BID) in 26 $(47.2\%)$, hyperfractionation II (1.35 Gy/fr., BID) in 18 $(32.7\%)$, and accelerated fractionation (1.6 Gy/fr., BID) in 2 $(3.6\%)$. In chemotherapy, 5-FU ($1,000\;mg/m^2$ daily for 5 consecutive days) and cisplatin ($100\;mg/m^2$ on day 1) were administered in a cycle of 3 weeks interval, and a total of 1 to 3 cycles (average 2..3 cycles) were given prior to radiation therapy. Follow up duration was $1\~195$ months (median 28 months). Results : Overall 2 and 5 year survival rates were $40.6\%\;and\;27.6\%;\;50.0\%\;and\;30.0\%$ in Group I, and $36.4\%\;and\;26.3\%$ in Group II, respectively. Complete local control rates in Group I and II were $70.0\%\;and\;67.7\%$, respectively. The response to radiotherapy and nodal stage were statistically significant prognostic factors. The complication rate was increased in Group II and was decreased in hyperfractionation. Conclusion : The response to radiotherapy and nodal stage were valid factors to indicate the degree of control over the hypopharyngeal cancer. The induction cisplatin, 5-Fu chemotherapy was not valid in terms of local control rate and survival rate, but did contribute to an increased complication rate. The use of hyperfractionation was valid to reduce the late radiation complications.

• Horticultural Science & Technology
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• v.17 no.5
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• pp.572-577
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• 1999

Research was initiated to evaluate plant growth regulator effects on the vertical shoot growth of Korean lawngrass and to determine desirable growth regulator and its rate. The experiments were conducted twice at different sites in 1995. All the tested growth regulators inhibited the growth, but the inhibition period was variable among the product in Experiments I and II. During the first week after treatment, there was approximately 10 to 20% growth reduction in most of the treated plots. In the amidochlor-treated plots, growth suppression was effective for 3 to 4 weeks at low to medium rates ($0.60mL{\cdot}m^{-2}$). A Type II growth regulator, trinexapac-ethyl exceeding the medium rate of $0.08mL{\cdot}m^{-2}$ consistently tended to suppress vertical shoot growth for 8 weeks, being above 35% reduction in both experiments. In the plots applied with mefluidide, growth suppression appeared with foliar discoloration 3 or 4 days earlier than the other growth regulators and continued to work till the 8 weeks after treatment. Suppression intensity on vertical shoot growth increased with time after treatment up to a certain period of time, depending on growth regulators. Generally, the higher the application rate, the greater the suppression intensity. Seasonal variation of activity and effectiveness of growth regulators was observed, resulting in lower suppression intensity in July than in June. It is expected to reduce mowing requirements by 30 to up to 60% for a certain period with a specific growth regulator. In low to medium maintenance of Korean lawngrass turf, a long-term suppression may be more effectively accomplished with trinexapac-ethyl rather than mefluidide and amidochlor in terms of vertical shoot growth inhibition. Therefore, turf managers will need to select proper growth regulator and determine optimum rate of application for turfgrass management, based on a defined period of mowing reduction.