• Journal of KIISE
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• v.42 no.1
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• pp.107-113
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• 2015

In a database system, updates on pages that are made by a transaction should be stored in a secondary storage before the commit is complete. Generic secondary storages have volatile DRAM caches to hide long latency for non-volatile media. However, as logs that are only written to the volatile DRAM cache don't ensure durability, logging latency cannot be hidden. Recently, a flash SSD with capacitor-backed DRAM cache was developed to overcome the shortcoming. Storage devices, like those with a non-volatile cache, will increase transaction throughput because transactions can commit as soon as the logs reach the cache. In this paper, we analyzed performance in terms of transaction throughput when the SSD with capacitor-backed DRAM cache was used as log storage. The transaction throughput can be improved over three times, by committing right after storing the logs to the DRAM cache, rather than to a secondary storage device. Also, we showed that it could acquire over 73% of the ideal logging performance with proper tuning.

• Journal of Chest Surgery
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• v.45 no.5
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• pp.287-294
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• 2012

Background: Biologic valved grafts are important in cardiac surgery, and although several types of graft are currently available, most commercial xenografts tend to cause early disfiguration due to intimal proliferation and calcification. We studied the graft failure patterns on non-fixed and glutaraldehyde-fixed pulmonary xenograft in vivo animal experiment. Materials and Methods: Pulmonary valved conduits were obtained from the right ventricular outflow tract of eleven miniature pigs. The grafts were subjected to 2 different preservation methods; with or without glutaraldehyde fixation: glutaraldehyde fixation (n=7) and non-glutaraldehyde fixation (n=4). The processed explanted pulmonary valved grafts of miniature pig were then transplanted into eleven goats. Calcium quantization was achieved in all of the explanted xenograft, hemodynamic, histopathologic and radiologic evaluations were performed in the graft which the transplantation period was over 300 days (n=7). Results: Grafts treated with glutaraldehyde fixation had more calcification and conduit obstruction in mid-term period. Calcium deposition also appeared much higher in the glutaraldehyde treated graft compared to the non-glutaraldehyde treated graft (p<0.05). Conclusion: The present study suggests that xenografts prepared using glutaraldehyde fixation alone appeared to have severe calcification compared to the findings of non-glutaraldehyde treated xenografts and to be managed with proper anticalcification treatment and novel preservation methods. This experiment gives the useful basic chemical, histologic data of xenograft failure model with calcification for further animal study.

• Journal of The Korean Society of Clinical Toxicology
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• v.12 no.2
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• pp.54-62
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• 2014

Purpose: The purpose of this study was to compare prescription patterns and clinical features according to clinical departments in sedative-hypnotic intoxication. Methods: This was a retrospective study of histories, substances of poisoning, acquisition routes, clinical courses, and outcomes of patients treated for acute intoxication in a single emergency medical center from January, 2011 to December, 2013. Results: A total of 769 patients were treated for acute intoxication, 281 patients ingested sedative hypnotics during the study period. Among 281 patients, 155 patients were prescribed by psychiatric department and 80 patients were prescribed by non-psychiatric department. Benzodiazepines were more likely to be prescribed by psychiatrists, and zolpidem was preferred by non-psychiatrists (p<0.001). Non-psychiatrists were more likely to prescribe short acting benzodiazepines than psychiatrists (p<0.001). However, there was no statistically significant difference in the clinical outcomes, including prevalence of admission to ICU, ventilator care, and length of stay in ICU. In patients prescribed by non-psychiatrists, there were more patients prescribed without psychiatric diagnosis and diagnosed as major depression disorder after hospitalization. Conclusion: To promote rational prescribing of sedative hypnotics, proper psychiatric evaluation should be performed before prescribing, and educational programs including the contents of interactions and side effects of sedative hypnotics are needed.

• The Journal of the Acoustical Society of Korea
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• v.40 no.2
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• pp.109-120
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• 2021

This paper proposes the H∞ norm based data association gate method to apply robustly the data association gate of passive sonar automatic target tracking which is on non-linear targets in dense cluttered environment. For target tracking, data association method selects the measurements within validated gate, which means validated measuring extent, as candidates for the data association. If the extent of the validated gate in the data association is not proper or the data association executes under dense cluttered environment, it is difficult to maintain the robustness of target tracking due to interference of clutter measurements. To resolve this problem, this paper proposes a novel gating method which applies H∞ norm based bisection algorithm combined with 3-σ gate method under Gaussian distribution assumption and tracking error covariance. The proposed method leads to alleviate the interference of clutters and to track the non-linear maneuvering target robustly. Through analytic method and simulation to utilize simulated data of horizontal and vertical bearing measurements, improvement of data association robustness is confirmed contrary to the conventional method.

• Journal of Powder Materials
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• v.28 no.2
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• pp.103-109
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• 2021

High-entropy alloys have excellent mechanical properties under extreme environments, rendering them promising candidates for next-generation structural materials. It is desirable to develop non-equiatomic high-entropy alloys that do not require many expensive or heavy elements, contrary to the requirements of typical high-entropy alloys. In this study, a non-equiatomic high-entropy alloy powder Fe_49.5Mn₃₀Co₁₀Cr₁₀C_0.5 (at.%) is prepared by high energy ball milling and fabricated by spark plasma sintering. By combining different ball milling times and ball-to-powder ratios, we attempt to find a proper mechanical alloying condition to achieve improved mechanical properties. The milled powder and sintered specimens are examined using X-ray diffraction to investigate the progress of mechanical alloying and microstructural changes. A miniature tensile specimen after sintering is used to investigate the mechanical properties. Furthermore, quantitative analysis of the microstructure is performed using electron backscatter diffraction.

• Journal of The Korean Association For Science Education
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• v.29 no.2
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• pp.253-266
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• 2009

This study was focused on analyzing students' informal reasoning patterns and their considerations in decision-making on socioscientific issues. This study involved 20 undergraduate students (10 biology majors and 10 non-biology majors) and showed how the two groups responded on socioscientific issues. Semi-structured interviews were conducted twice respectively based on six scenarios of gene therapy and human cloning. The result showed 93% of the total number of participants' decisions were made by rationalistic reasoning, whereas emotional reasoning was 49%, and intuitive reasoning was 27%. Students usually used two or three informal reasoning patterns together. Most of the students took more consideration on social factors. Some perceived ethical and moral implications of the issues, but they did not consider them seriously. They made their decisions depending on their own values, etc. 65% of the participants got their information on socioscientific issues from the mass media. Biology majors hardly used intuitive reasoning compared to non-biology majors. The Biology major group took into deep considerations on socioscientific issues while the non-biology major group seemed to interpret the given scenarios simply. This implied that the content knowledge was a significant factor of their decision-making. Therefore, it is necessary to develop proper science courses for non-major students to improve their decision-making on socioscientific issues. So, when we develop educational materials or programs, we should consider students' reasoning patterns, their considerations in decision-making, and their content knowledge. And because the mass media has the potential to play a key role for an effective education, we need to make a plan to make a practical application.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.405-412
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• 2009

The purpose of this study investigated the effect of Au coating on adhesion between porcelain matrix and metal substructure interface. Titanium, Ni-Cr alloy and Co-Cr alloy are well known as proper metal for the dental restorations. The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. However, adhesion between dental alloys and porcelain is related to diffusion of oxygen during ceramic firing. The excessive oxidized layers make hard adhesion between dental alloy and ceramic. Ni-Cr and Co-Cr specimens were divided into test and a control group and Titanium specimens were divided into three test groups and a control group. Each group had 20 specimens. The adhesion characteristics of porcelain and metal with Au coating layer and without Au coating layer were observed with scanning electron microscopy(SEM). The adhesion was evaluated by a biaxial flexure test and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that Au coating layer is effective barrier to diffuse oxide layer completely protect non-precious alloys from oxidation during the porcelain firing. The SEM photomicrographs of cross-section specimens showed a smooth interface between Au coating layer and metals and porcelain which suggested proper chemical bonding, and no gap, porosity were observed. The mode of failure was mainly adhesive for Ti tested specimens, but mixed failures with adhesive and cohesive were observed in Ni-Cr and Co-Cr specimens. The adhesion between non-precious metals and porcelain would not be improved by Au coating agent. However, It is suggested that the continuous study is required further investigation and development.

• The Journal of Korean Medicine
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• v.35 no.3
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• pp.22-31
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• 2014

Objectives: The aim of this study was to identify the complementary and substitute relationships between the use of Korean medicine (KM) and that of Western medicine (WM) in the treatment of musculoskeletal disease. Methods: We analyzed the 2009 Korea Health Panel dataset. General characteristics and the medical utilization of respondents were analyzed descriptively. Logistic regression, negative binominal regression, and Tobit regression analysis were used to identify the relationships between the use of KM and the use, visit frequency, and expenses of WM, respectively. Results: In the treatment of musculoskeletal disease, KM use and non-herbal treatments with Korean medicine significantly reduced WM use. Herb medication use significantly increased WM visit frequency. There were no significant relationships between KM use and WM expenses. Conclusions: There are substitute relationships between WM use and KM use, especially non-herbal treatments in KM. Therefore we need to develop the clinical protocols of KM and WM treatments in the treatment of musculoskeletal disease for proper distribution medical resources.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.427-431
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• 2013

Angioedema is defined as self-limited, localized swelling. The swelling is asymmetric, non-pitting, and non-tender. Common locations of swelling include periorbital area, lips, tongue, extremities, and bowel wall. A 54-year-old woman visited our hospital with the clinical complaint of left maxillary swelling. Swelling of the left maxillary area was diffuse and temperature of the involved area was normal. No infectious source was found on panoramic radiography and cone-beam computed tomography. After considering the patient's medical history and assessing clinical examination, we suspected angioedema and administered corticosteroid only. In the oral and maxillofacial area, proper diagnosis and prompt treatment of angioedema is important because angioedema of the tongue or larynx may lead to airway obstruction or a life-threatening condition.

• Structural Engineering and Mechanics
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• v.49 no.5
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• pp.631-644
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• 2014

Seismic assessment and retrofitting of existing structure is a complicated work that typically requires more sophisticated analyses than performing a new design. Before the implementation of a Code for seismic design of buildings (GBJ 11-89), not enough attention has been paid on seismic performance of structures and a great part of the existing reinforced concrete structures built in China have been poorly designed according to the new version of the same code (GB 50011-2010). This paper presents a case study of seismic assessment of a non-seismically designed reinforced concrete building in China. The structural responses are evaluated using the nonlinear static procedure (the so-called pushover analysis), which requires its introduction within a process that allows the estimation of the demand, against which the capacity is then compared with. The capacity of all structural members can be determined following the design code. Based on the structural performance, suitable retrofitting strategies are selected and implemented to the existing system. The retrofitted structure is analyzed again to check the effectiveness of the rehabilitation. Different types of retrofitting strategy are discussed and classified according to their complexity and benefits. Finally, a proper intervention methodology is utilized to upgrade this typical low-rise non-ductile building.