• Journal of Adhesion and Interface
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• v.8 no.4
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• pp.14-22
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• 2007

In the present study, the effect of milled glass powder and liquid-type nitrile rubber (NBR) on the thermal stability of phenolic resin and the dynamic mechanical properties of glass braid/phenolic composites has been investigated by means of thermogravimetric analysis and dynamical mechanical analysis. It was found that both milled glass power and NBR filled in the waterborne phenolic resin significantly influenced the thermal stability of phenolic resins and the storage modulus and tan delta of the composites. The presence of glass powder increased the thermal stability of the phenolic resin, whereas the presence of NBR resulted in the weight loss in the specific temperature range. The thermal stability of the phenolic resins without and with the fillers was dependent not only on the cure temperature but also on the cure time. The variation of the storage modulus and tan ${\delta}$ of strip-type glass braid/phenolic composites was also influenced with the introduction of glass powder and NBR to the phenolic matrix as well as by the cure conditions given.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.219-227
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• 2008

As found in research on constraint satisfaction problems, the choice of variable ordering heuristics is crucial for effective solving of constraint optimization problems. For the special problems such as energy-efficient clustering in heterogeneous wireless sensor networks, in which cluster heads have an inclination to be near a base station, we propose a new approach based on the static preferences variable orderings and provide a pnode heuristic algorithm for a specific application. The pnode algorithm selects the next variable with the highest Preference. In our problem, the preference becomes higher when the cluster heads are closer to the optimal region, which can be obtained a Priori due to the characteristic of the problem. Since cluster heads are the most dominant sources of Power consumption in the cluster-based sensor networks, we seek to minimize energy consumption by minimizing the maximum energy dissipation at each cluster heads as well as sensor nodes. Simulation results indicate that the proposed approach is more efficient than other methods for solving constraint optimization problems with static preferences.

• Journal of Korean Clinical Nursing Research
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• v.17 no.2
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• pp.204-214
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• 2011

Purpose: This study was aimed to provide information on the awareness of patient safety culture and safety care activities among operating room (OR) nurses and to analyze the factors influencing the safety care activities. Methods: For this descriptive research, self-reported questionnaires were administered to 168 OR nurses who were working at the university-affiliated and general hospitals. The collected data were analyzed using descriptive statistics, t-test, ANOVA, $Scheff{\grave{e}}$ test, Pearson's correlation coefficient and Stepwise multiple regression with SPSS/WIN 17.0. Results: The mean score of the awareness on patient safety culture was 3.27 out of 5 points and that of safety care activity was 4.31 out of 5. The statistically significant difference was found between experience of safety education and the awareness on patient safety culture. Also, the scores of safety care activities were significantly different according to OR nurses' position, education levels, and experience of safety education. There was a positive correlation between the awareness of patient safety culture and safety care activity. Their explanatory power on safety care activity was 8.8%, which includes working environment in operating room 3.3% and nursing position 5.5%. Conclusion: Compared to the level of patient safety activities, the OR nurses' awareness on patient safety culture was low. Given the specific characteristics and conditions in each hospital, it needs to increase the OR nurses' awareness on patient safety culture and activities related to patient safety.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.182-193
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• 2021

The purpose of this study is to grasp the influence of incivility and stress experienced by Dental Hygiene (Department) students in clinical practice upon professional identity. The research subjects are totally 297 people. As a result of the analysis, The professional identity had a significant difference in a reason for application, in the academic department satisfaction, and in the satisfaction with the training institution among general characteristics. It was indicated that the incivility and the clinical-practice stress have a positive correlation and that the clinical-practice stress and the professional identity have a negative correlation. The influential element upon professional identity was a conflict with a patient among sub-factors of the academic department satisfaction and the clinical-practice stress. The explanation power accounted for 17.9%. Accordingly, to improve the professional identity, there is a need to develop and apply a program of reducing and coping with the clinical-practice stress. And a specific plan is necessary for increasing the satisfaction with the academic department.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2427-2444
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• 2021

The lack of plant-side energy storage analysis to support nuclear power plants (NPP), has setup this research endeavor to understand the characteristics and role of specific storage technologies and the integration to an NPP. The paper provides a qualitative review of a wide range of configurations for integrating the energy storage system (ESS) to an operating NPP with pressurized water reactor (PWR). The role of ESS technologies most suitable for large-scale storage are evaluated, including thermal energy storage, compressed gas energy storage, and liquid air energy storage. The methods of integration to the NPP steam cycle are introduced and categorized as electrical, mechanical, and thermal, with a review on developments in the integration of ESS with an operating PWR. By adopting simplified off-design modeling for the steam turbines and heat exchangers, the results show the performance of the PWR steam cycle changes with respect to steam bypass rate for thermal and mechanical storage integration options. Analysis of the integrated system characteristics of proposed concepts for three different ESS suggests that certain storage technologies could support steady operation of an NPP. After having reviewed what have been accomplished through the years, the research team presents a list of possible future works.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.8
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• pp.845-854
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• 2019

In IoT environment, an intelligent agent is an autonomous entity with computing power that interacts with various things for specific purposes without human intervention. Recently, as the development of Internet technology has increased the size of resources and services that intelligent agents can utilize, an environment where intelligent agents can collaborate with each other is needed. To effectively support these changes, a method is needed to provide workspaces where intelligent agents can form various groups and collaborate on them. In this paper, we present TSpace which is an Ethereum-based group workspace for effective collaboration among intelligent agents. In TSpace, intelligent agents in IoT environment can use group service based on the Ethereum blockchain through the developed CoAP/RESTful web service. TSpace also introduces a new mechanism for managing Ethereum wallets of agents accessing group services and for creating Ethereum transactions using them.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.7
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• pp.884-889
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• 2021

The number of people infected with Covid-19 in Korea seemed to be gradually decreasing thanks to various efforts such as social distancing and vaccines. However, just as the number of infected people increased after a particular incident on February 20, 2020, the number of infected people has been increasing rapidly since December 2020 by approximately 500 per day. Therefore, the future Covid-19 is predicted through the Prophet algorithm using Kaggle's dataset, and the explanatory power for this prediction is added through the coefficient of determination, mean absolute error, mean percent error, mean square difference, and mean square deviation through Scikit-learn. Moreover, in the absence of a specific incident rapidly increasing the cases of Covid-19, the proposed method predicts the number of infected people in Korea and emphasizes the importance of implementing epidemic prevention and quarantine rules for future diseases.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1417-1427
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• 2019

In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a $20mm{\times}20mm{\times}5mm$ CZT crystal with $8{\times}8$ pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes $^{57}Co$, $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59%, 9.56%, 6.08%, and 5%-4.61%, 2.94%, 2.08%, and 2.2%, respectively. For the Compton imaging, simulations and experiments using one $^{137}Cs$ source with various angular positions and two $^{137}Cs$ sources were performed. Individual and multiple sources of $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the $^{137}Cs$ experiments were approximately $7^{\circ}-9^{\circ}$ and $5{\times}10^{-4}-7{\times}10^{-4}$, respectively. The distortions of the source distribution were proportional to the offset angle.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.1-8
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• 2019

Due to the major role played by several species of Streptococcus in the etiology of periodontitis, it is important to assess the pattern of Streptococcus pathogenic pathways within the infected subgingival pockets using a bacterial specific 16S rRNA fragment. From the total of 50 patients with periodontitis included in the study, only 23 Streptococcal isolates were considered for further analyses, in which their 16S rRNA fragments were amplified and sequenced. Then, a comprehensive phylogenetic tree was constructed and in silico prediction was performed for the observed Streptococcal species. The phylogenetic analysis of the subgingival Streptococcal species revealed a high discrimination power of the 16S rRNA fragment to accurately identify three groups of Streptococcus on the species level, including S. salivarius (14 isolates), S. anginosus (5 isolates), and S. gordonii (4 isolates). The employment of state-of-art in silico tools indicated that each Streptococcal species group was characterized with particular transcription factors that bound exclusively with a different 16S rRNA-based secondary structure. In conclusion, the observed data of the present study provided in-depth insights into the mechanism of each Streptococcal species in its pathogenesis, which differ in each observed group, according to the differences in the 16S rRNA secondary structure it takes, and the consequent binding with its corresponding transcription factors. This study paves the way for further interventions of the in silico prediction, with the main conventional in vitro microbiota identification to present an interesting insight in terms of the gene expression pattern and the signaling pathway that each pathogenic species follows in the infected subgingival site.

• Korean Journal of Clinical Oncology
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• v.14 no.2
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• pp.120-127
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• 2018

Purpose: The purpose of this study was to determine the immunologic role of lymph node (LN) and stage migration by assessing LN count and metastatic LN count. Methods: A total of 2,117 patients with gastric adenocarcinoma located in the body and antrum who underwent distal/subtotal gastrectomy with D2 LN dissection between January 1, 1998 and December 31, 2008 were enrolled. LN count and number of metastases were determined in the N1 tier (area of D1 dissection) and N2 tier (area of D2 dissection). The lower and upper quartiles of LN counts in the same pN stage were grouped to compare the prognosis and LN positivity according to the LN tier. Results: Stage migration from N1 tier to N2 tier occurred in 3.2% of cases. The 5-year disease-specific survival rates of the upper and lower LN count groups within the N1 tier were 91.0% and 86.7% (P=0.01), respectively. LN positivity in the N2 tier of the lower LN count group was higher than that of the upper LN count group (14.1% vs. 8.2%, P<0.01). Stage migration in the N2 tier of the lower LN count group was also higher than that of the upper LN count group (4.6% vs. 1.8%, P<0.01). Conclusion: The lower LN count group had a decreased survival rate compared to that of the upper LN count group, suggesting that perigastric LN has an immunological defense role in weakening the disseminating power of metastatic tumor cells, as indicated by the LN count.