• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.33-41
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• 2007

With the development of the multicast technology, the realtime strategy among the group applications using the multicast routing is getting more important. An essential factor of these real-time application is to optimize the Delay- and delay Variation-Bounded Multicast Tree(DVBMT) problem. This problem is to satisfy the minimum delay variation and the end-to-end delay within an upper bound. The DVBMT problem is known as NP-complete problem. The representative algorithms for the problem are DVMA, DDVCA, and so on. In this paper, we show that the proposed algorithm outperforms any other algorithm. The efficiency of our algorithm is verified through the prerformance evaluation and the enhancement is up to about 9% to 29% in terms of the multicast delay variation. The time complexity of our algorithm is $O(mn^2)$M.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.253-258
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• 2012

The effects of active sites and valence states were investigated over $Pd/TiO_2$ catalyst on simultaneous oxidation of $CH_4$ and CO. The Pd species (PdO) crystallite size increased with increasing Pd loadings, which results in enhancement of the activity of $CH_4$ oxidation. Different results from the activity of $CH_4$ and CO oxidation were shown to be dependent on the Pd valence state on the surface of the catalyst prepared through a thermal treatment. XRD and $H_2-TPR$ analysis confirmed that $Pd^{2+}$species was predominated in the calcination catalyst, while $Pd^0$species was predominated in the reduction catalyst. Additionally, it could be found that the valence state of Pd was a more important factor on the catalytic activity than that of factors as the surface area and pore volume. The reaction mechanism of $CH_4$ and CO followed by the valence state of Pd could be identified using FT-IR analysis.

• Journal of Hospice and Palliative Care
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• v.18 no.4
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• pp.306-313
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• 2015

Purpose: This study was performed to explore factors that influence attitudes toward terminal care in nursing students. Methods: Data were collected using a self-reported questionnaire filled by 175 nursing students at a university in a metropolitan city B. Data were analyzed using descriptive analysis, t-test, ANOVA, Pearson correlation coefficients and stepwise multiple regression with the SPSS/WIN 22.0 program. Results: Attitudes toward terminal care in nursing students was significantly correlated with communication competence (r=0.438, P<0.001), spirituality (r=0.374, P<0.001), and gratitude (r=0.318, P<0.001). Communication competence explained 18.7% of the variance in attitudes toward terminal care. Conclusion: The study shows communication competence is an important factor for attitudes toward terminal care in nursing students. Therefore, it is necessary to develop a communication competence enhancement program to foster nursing students with appropriate attitudes toward terminal care.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.27-32
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• 2002

The purpose of this study was to evacuate the effects of the number of tied hollow fibers in a novel membrane oxygenator that satisfied the limiting factor of minimizing the friction loss in the intravascular blood flow Pattern. The membrane oxygenator is a bundle consisted of several hundred ho1low fibers haying the outside diameter of 380 $\mu m$ and the axial jacket length of 600 mm. The eight different variation of tied hollow fibers in a bundle were designed. and the liquid flow pattern was controlled by a pump. The liquid pressure drop was measured by in vitro experiments using water and g1ycero1. Uniform blood flow pattern was observed for each number of tied hollow fibers. Pressure drop was 13-16 mmHg outside of the membrane oxygenator consisting of up to 700 ho1low fibers. More effective contact of liquid with the tied ho1low fibers was observed as a decrease in the number of the tied hollow fibers. and resulted in the enhancement of the friction tractor

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.118-124
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• 2017

An air cooling, open cathode type polymer electrolyte membrane fuel cell (PEMFC) has the advantages of system simplification and cost effectiveness. Open cathode PEMFC could suffer from reduced performance due to the membrane dehydration in low humidity of air. Effects of the cathode air flow rate, anode purge interval and long term storage on PEMFC performance were investigated in this work. Fan voltage is an important factor on air cooling PEMFC performance because the cathode air flow rate and stack temperature were controlled by fan voltage. The dead ended anode (DEA) method was applied to increase hydrogen usage. Periodical purge was used to discharge accumulated water and gas. The influence of long term non-operating condition on PEMFC performance degradation due to the membrane dehydration was also studied and the quick recovery method was developed.

• Journal of Life Science
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• v.16 no.6
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• pp.1066-1070
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• 2006

Smooth muscle cell (SMC) proliferation is important in the pathogenesis of vascular proliferative disorders. Understanding of the molecular mechanism underlying SMC growth after arterial injury would have therapeutic implications. Here we report that receptor activator of $NF-{\kappa}B$ ligand (RANKL), a member of tumor necrosis factor (TNF) family, promotes the proliferation of SMC, leading to decreased expression of p21 and enhancement of SMC growth. ERK and p38 phosphorylation was enhanced after RANKL treatment in SMC. Inhibition of ERK/p38 MAPK activity by PD98059/SB203580 completely abolished RANKL-induced proliferation of SMC, indicating ERK and p38 MAPK are essential for RANKL-induced SMC proliferation. Taken together, our findings demonstrate that RANK-RANKL-ERK/p38 pathway is important for proliferation of SMC and that these molecules may be the new therapeutic targets for the prevention of vascular diseases.

• Journal of Family Resource Management and Policy Review
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• v.19 no.1
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• pp.139-161
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• 2015

The number of Healthy Family Support Centers has increased and the services for enhancement of family strength have extended during the past ten years since the Framework Act on Healthy Families was enacted. It is time to pay attention to the empowerment for Healthy Family Specialist because their capability is directly linked to improve the quality of services, which means the satisfaction of family services and the quality of family policy. In this context, this study investigate organizational experience of Healthy Family Specialists and suggest the empowerment plan to enhance their capability. We conducted in-depth interviews for 9 Healthy Family Specialists who is currently working at Healthy Family Support Centers as a manager status during June 2014. We analyzed organizational experiences through job commitment and job satisfaction and empowerment plans through their strength and weakness. Our findings revealed that job commitment and job satisfaction of Healthy Family Specialist are relatively low due to a poor working condition and a low brand awareness. Also, the capability of Healthy Family Specialists is an important factor to determine their job commitment and job satisfaction, and it can impact on the long service. These results suggest that the payroll system, increment of salary, career recognition, employee benefit, systematic operation, and motivation are needed to improve their job satisfaction. There are various ways to improve professional capability of Healthy Family Specialists besides education program. This study contributes to make the plan of empowerment for Healthy Family Specialists and it also contributes to improve the service quality of family policy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1259-1266
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• 2010

M2M communication is considered as a key enabling technology to monitor the status of objects, vehicles, humans through auto-configuring wireless networks. In M2M network, there are active research activities to enhance the reliability on data while being collected from wireless sensor network. The reliability issue becomes more important as wireless sensor networks carry multimedia data, which is delay sensitive. The interference caused by the adjacent neighbor sensor nodes is a major factor in network performance degradation, which becomes more severe in multi-hop routing environment. In this paper, we propose inerfernce-free multipath routing protocol for M2M wireless network for enhancement of packet delay performance. The simulation results show that the proposed routing algorithm outperforms the existing routing protocols in terms of packet delay and throughput.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.786-795
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• 1999

To detect the precise of arrival of target signal in real ocean environments, Inverse beamformnig(IBF) solutions to the Inverse beamforming integral equation are surveyed theoretically and the performance properties of the IBF are analyzed with simulations. IBF-Cardioid beamforming algorithm is proposed for port/starboard discrimination and the performance gains are studied with simulations. It is shown that IBF has a 3 dB array noise gain advantage over CBF under ideal conditions. This 3 dB array noise gain advantage is proven by theocratical studies and simulations. This array noise gain advantage leads to a minimum detectable level advantage for IBF output compared with CBF output. The fact that the IBF beamwidth is narrower than the CBF beamwidth by a factor of 0.68 proves the performance of detection and spatial resolution improvement. Comparing the simulation results of IBF-Cardioid beamforming and Conventional Cardioid beamforming, it is shown that IBF-Cardioid beamformer have performance enhancement in minimum detection level, detection accuracy and resolution.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.31-40
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• 2013

For the matter of elevator, one of the multi-use facilities for unspecified public, the JIS has re-established and reformed to apply to the environment in South Korea for the past 20 years. In the aspect of safety assurance, it was inevitable to suggest improved measures. The government, Ministry of Public Administration and Security has secured the safety by enhancing the safety management functions in the elevator inspection standards and expanding its safety device measures. Further, the international inspection standard has been introduced, which is about unifying inspection standard system into the international standard code. In March 14th 2012, the international standard (EN) has been amended and fully announced. Escalator and passenger conveyor among lift devices have several common danger factor that cause safety accident. First, the accident caused by decreased braking power of brake. Second, the accident caused by the rate difference between handrail and tread-board. Third, the accident caused by defects of contraflow preventing device or carelessness inspection. Fourth, the accident caused by wet tread-board or wet floor of platform which makes passenger slip and fall. As the improvements to prevent and reduce these negligent accidents, the inspection list to check and methods should be subdivided and applied for each accident likelihood cause for safety management enhancement and safety assurance of existing escalator and passenger conveyors. The escalators and passenger conveyors without safety devices in existence should be obliged to modify the part of the system or install additional safety device. With making these measures obligations, it requires to improve the system to be suitable for the international inspection standard and to have measures to prevent safety accidents. It also needs to arrange improvements for skid accident of tread-board by the external environment factors such as snow and rain.