• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1329-1335
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• 2009

In this paper, we propose a new medium access control protocol referred to as DCTW (Dual Channel Transmission Scheme for wireless body area networks). Wireless body area networks (WBANs) requires prioritization mechanism for life-critical data to transmit the data as early as possible. The proposed DCTW exploits a narrow band for transmitting life-critical data while it uses a broadband channel to transmit normal data. Since the narrow band is dedicated to life-critical data, the DCTW can effectively reduce the delay of life-critical data transmission. Through extensive simulation, we show the DCTW outperforms other existing schemes.

• Journal of Korean Critical Care Nursing
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• v.1 no.1
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• pp.59-71
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• 2008

Purpose: This study was to identify the effects of simulation-based training for advanced cardic life support on the competence of nurses in critical care settings. Methods: In this study, a nonequivalent control pretest-post test quasi-experimental design was used. Data were collected from May 1 to June 1, 2006 at one general hospital in W city. Among 40 nurses in critical care settings, twenty were assigned to the experimental group and twenty to the control group. Nurses in the experimental group received simulation-based training for advanced cardiac life support. Measurement tool were ACLS related knowledge and skills developed by AHA & Mega Code (2005) and some items were modified. The collected data were statistically processed using SPSS version 12.0 for Windows, and analyzed using descriptive statistics, $X^2$test, t-test, paired ttest, Pearson correlation coefficients. Results: 1) Hypothesis 1“: Nurses who received simulationbased training would have more knowledge of advanced cardiac life support than nurses who received traditional training”, was supported (t=11.51, p=.00). 2) Hypothesis 2: “Nurses who received simulation-based training would have better advanced cardiac life support skills than nurses who received traditional training”, was supported (t=2.38, p=.00). Conclusion: Simulation-based training for advanced cardiac life support is an effective strategy for increasing the competence of nurses in advanced cardiac life support in critical care settings.

• Journal of Korean Critical Care Nursing
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• v.16 no.3
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• pp.73-86
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• 2023

Purpose : This study aimed to identify the factors affecting the quality of life of lung transplant patients. Method : The participants were patients who received lung transplants at a general hospital in City Y. Data were collected through structured questionnaires from June 2023 to August 2023. General characteristics, lung transplantation-related characteristics, quality of life, functional disability, treatment compliance, social support, anxiety, and depression-were measured. For data analysis, hierarchical multiple regression was performed using SPSS/WIN 29.0. Results : In the final model, quality of life was associated with income, self-help group attendance, functional disability, social support, treatment compliance, and anxiety and depression. Together, they explained 61.2% of the total variance in the results. Conclusion : Our findings suggest that improving lung transplant patients' quality of life requires active intervention in stress management to perform treatment instructions well, a social support system that can help them financially, and encouraging and participating in social activities as patients.

• Journal of Mechanical Science and Technology
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• v.18 no.6
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• pp.915-923
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• 2004

This study investigated the fatigue lives and mechanical properties of the carbon black filled natural rubber for the vibration-proof parts of the railway vehicle and automobile. The carbon blacks were one of the sources of crack nucleation and crack propagation in the rubber matrix, like the cementite and the maganese sulfide in iron matrix. Different kinds of carbon blacks resulted in different fatigue lives, critical J-values, and fracture morphologies. It was noticed that the critical J-value remained almost the same regardless of the length of a pre-crack. In addition, different kinds of carbon blacks generated different fracture morphologies, and microscopic and macroscopic roughnesses. The critical J-value has linear relations to the roughness, and it seemed related to the size distribution of carbon black particles. By reviewing all the experi-mental data, we found the factors that were related to the fatigue lives, and the logarithmic value of the fatigue life could be linearly expressed by the combination of the critical J-value and the macroscopic roughness. We also proposed a new estimative equation of fatigue life.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1887-1894
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• 2001

The effects of carbon black on the material properties and the fatigue life of the carbon-black filled natural rubbers were investigated. Different kinds of carbon blacks resulted in different fatigue lives, hysteresis, and critical J-values. It was noticed that the hysteresis was inversely proportional to the difference between DBPA and CTAB, and the critical J-value was almost the same regardless of the length of a precrack. In addition, different kinds of carbon blacks resulted in different fracture morphologies, and micro-scale and macro-scale roughnesses. The critical J-value was proportional to the micro-scale roughness. and it seemed relate to the size distribution of carbon black particles. By reviewing all the experimental data. it was finally noticed that the logarithmic value of the fatigue life could be linearly expressed by a multiplication of the critical J-value and the logarithmic value of the hysteresis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.410-418
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• 2004

The multiaxial fatigue test under in-phase and out-of$.$phase load were performed to study what degradation phenomenon affects fatigue life with virgin and 3600 hrs degraded materials. The various kind of fatigue data fur fatigue life prediction were acquired under pure axial and pure torsional load of fully reversal condition. The models which was investigated are: 1) the von Mises equivalent strain range, 2) the critical shear plane approach method of Fatemi-Socie(FS) parameter, 3) the modified Smith-Watson-Topper(SWT) parameter. The result showed that, fatigue life by material degradation are decreased and life prediction which was used the FS parameter is not conservative but the best result.

• Journal of Power Electronics
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• v.17 no.3
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• pp.811-820
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• 2017

The reliability issue of IGBT is a concern for researchers given the critical role the device plays in the safety of operations of the converter system. The reliability of power devices can be estimated from the intermittent life test, which aims to simulate typical applications in power electronics in an accelerated manner to obtain lifetime data. However, the test is time-consuming, as testing conditions are not well considered and only rough provisions have been made in the current standards. Acceleration of the test by changing critical test conditions is controversial due to the activation of unexpected failure mechanisms. Therefore, full investigations were conducted on critical test conditions of intermittent life test. A design optimization process for IGBT intermittent life testing program was developed to save on test times without imposing additional failure mechanisms. The applicability of the process has been supported by a number of tests and failure analysis of the test results. The process proposed in this paper can guide the test process for other power semiconductors.

• The Korean Journal of Emergency Medical Services
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• v.24 no.1
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• pp.57-66
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• 2020

Purpose: The purpose of this study was to test the effect of simulation-based learning on knowledge, confidence, and critical thinking of paramedical students enrolled in the Korean Advanced Life Support (KALS) program. This study used a one group, pre-post test design. Methods: The subjects of this study were 79 paramedical students in D city. Data were collected before and after the simulation-based training using a structured questionnaire. The data were analyzed using SPSS version 22.0. Results: After the simulation-based KALS education, knowledge (t=-6.88, p<.001) and confidence (t=-10.12, p<.001) increased among paramedical students. There was a positive correlation between confidence and critical thinking disposition (r=0.37, p=.001). Conclusion: A practical module for simulation-based education that can improve knowledge, confidence, and critical thinking disposition related to professional resuscitation is needed for use with paramedical students. Additionally, follow-up studies should be conducted to verify the educational effects of such a program.

• Journal of Information Technology Applications and Management
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• v.20 no.4
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• pp.127-149
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• 2013

Competitiveness of service industry in Korea is relatively lower than OECD countries'. Korean government, therefore, has been trying to improve the competitiveness of service industry by accelerating information technology (IT) adoption. Even though most of factors of IT can be contributed to improve the financial performance, it may be affected differently among various industry types and life cycles of companies. Therefore, it is one of very important research issues to analyze the influential effect of IT considering industry types and organizational life cycles in service industries. The purpose of this study is to find out critical success factors of IT which influence financial performance considering different types and life cycles of service industries. We developed the model and identified key success factors of IT adoption as IT system quality, Information quality, IT maintenance, CEO support, IT education of organization, and IT competence of user. Additional analysis of moderating effect by organizational life-cycle and types of service industry are conducted. For data sampling 856 companies are participated and total 2,000 questionnaires are collected. Structural equation modeling method is conducted for statistical analysis. The results show that the model is valid and most of success factors of it are very useful for improving financial performance of service industries except organizational IT education. Moderating effect of industry types and organizational life cycles is valid but partially accepted. The results might be able to provide useful directions and guide lines of IT acceleration in service industries.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.965-970
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• 2005

In our previous study [14], we found that heat-shock exposure did not stimulate the neutral trehalase activity in Sacchromyces cerevisiae KNU5377, but did in ATCC24858. Consequently, the trehalose content in KNU5377 became 2.6 times higher than that in ATCC24858. Because trehalose has been shown to stabilize the structure and function of some macromolecules, the present work was focused to elucidate the relationship between trehalose content of these strains and thermal stabilities of whole cells, through differential scanning calorimetry (DSC), and to predict critical targets calculated from the hyperthermic cell killing rates. These analyses showed that the prominent DSC transition of both strains gave identical $T_m$ (transition temperature) values in exponentially growing cells, and that the $T_m$ values of critical targets was about $3^{\circ}C$ higher in KNU5377 than in ATCC24858. Both heat-shocked KNU5377 and ATCC24858 cells displayed similar shifts in their DSC transition profiles. On the other hand, the $T_m$ value of the critical target of KNU5377 was decreased by $2.1^{\circ}C$, which was still higher than ATCC24858 showing no changes. In view of these results, the intrinsic thermotolerance of KNU5377 did not appear to result from the stability of entire cellular components, but rather possibly from that of particular macromolecules, including critical targets, even though it should be investigated in more details. Although the trehalose levels in heat-shocked cells are significantly different, as described in our previous study [14], the overall pattern of thermal stabilities and their predicted critical targets in two heat-shocked strains seemed to be identical. These data suggest that the trehalose levels examined before and after heat shock of exponentially growing cells are not closely correlated with the stabilities of whole cells and/or critical targets in both yeast strains.