• Journal of Ecology and Environment
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• v.38 no.3
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• pp.343-352
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• 2015

The landscape setting of a habitat strongly influences the distribution, abundance, and species composition of waterfowl. Thus, habitat assessment is very important to understand the habitat characteristics that sustain waterfowl assemblages. In this study, we hypothesized that the excessive use of artificial materials when new wetlands are constructed negatively influences wintering waterfowl. To test this hypothesis, we measured environmental factors, assessed habitat, and investigated waterfowl at 13 artificial wetlands in the Nakdong River Basin. There were greater numbers of waterfowl species and individuals in artificial wetlands with high habitat assessment scores. In contrast, environmental factors did not affect waterfowl distribution. In particular, features of natural habitats, such as macrophytes and sandbars, and the surrounding land-use patterns were important factors for sustaining waterfowl assemblages in each created wetland. Our results show that promoting naturalness in wetlands and surrounding areas would increase the species diversity and abundance of waterfowl. Further, complex habitats, such as wetlands and some terrestrial habitats, support both aquatic and terrestrial species because mixed habitats feature a larger array of food sources than more limited habitats do.

• Korean Journal of Adult Nursing
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• v.29 no.2
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• pp.131-142
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• 2017

Purpose: The aims of the study were to investigate relationships among intensive care unit (ICU) nurses' attitude, role perception, and nursing stress related to life sustaining treatment (LST), and secondly, to identify factors influencing nursing stress about LST. Methods: Participants were 202 conveniently sampled ICU nurses from general hospitals in Korea with over 300 beds. From December 1, 2015 to January 31, 2016, data were collected using structured questionnaires. The questionnaire was designed to measure nursing stress related to LST. Content validity and reliability was established for the instrument. Results: Relationships were found between attitude and role perception, and between role perception and nursing stress about LST. Participants' role perception, gender, education level, and the experience of dealing with family members of patients receiving LST accounted for 13% of variance in nursing stress about LST. Conclusion: Results confirmed that ICU nurses' role perception affects nursing stress about LST. Accordingly, the nursing education programs related to LST should aim to enhance role perception of nurses, and strategies to reduce the nursing stress about LST of the nurses in ICU need to be further developed.

• Journal of Korean Academy of Nursing
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• v.31 no.2
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• pp.279-291
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• 2001

Rapid progress in modern medical technology has made it possible to sustain life and/or delay death using 'heroic' treatments. The availability of life-sustaining treatment brings several issues in end-of-life care such as 'dying with dignity' and an radical increase in health care costs. The use of Advance Directives(AD) have been widely heralded by health care providers, gerontologists, and advocacy groups as means of protecting patients' right to accept or refuse life-sustaining treatment in end-of-life care. The use of AD can not only improve patients' autonomy and quality of life but also bring efficiency in distributing health care resources. The proportion of older persons in Korean population has been increasing. Those 65 years of age or over were about 7 percent of the population. Death and dying is not limited to older persons, but it is more prevalent among them. In conjunction with an aging population and the increasing prevalence of death, the issues of death and dying will become crucial in near future in terms of 'dying with dignity', 'autonomy', and 'self-control'. This paper attempts to explode and establish the concept of advance directives (AD) based on literature review. Data sources are computer searches with the MEDLINE database. Due to the lack of prior study on AD for a Korean cases, studies abroad are reviewed. This paper suggests the need for future study on the possibility of the use of AD in Korea.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.352-355
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• 2006

A new PWM-controlled quasi-resonant converter for high efficiency PDP sustaining power module is proposed in this paper. The load regulation of the proposed converter can be achieved by controlling the ripple of the resonant voltage across the resonant capacitor with hi-directional auxiliary circuit, while the main switches are operating at the fixed duty ratio and fixed switching frequency. Hence, the waveform of currents can be expected to be optimized on the conduction loss. Furthermore, the proposed converter shows the good ZVS capability, simple control circuits, no high voltage ringing problem of rectifier diodes, no DC offset of the magnetizing current and low voltage stress of power switches. In this paper, operational principles, analysis and design considerations are presented. Experimental results demonstrate that the output voltage can be controlled well by the auxiliary circuit as PWM method.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.46-49
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• 2006

The LLC series resonant converter with a LLT(Inductor-Inductor-Transformer) transformer for PDP V sustaining power supply is presented. LLT transformer used to combine the inductor and transformer into one unit has the increased leakage inductance in the primary and secondary due to the winding method and the use of the gaped core. The increased leakage inductance in the primary and secondary of LLT transformer can be impacted on the DC voltage gain characteristics of LLC series resonant converter. In this paper, DC gain characteristics and the experimental results of the LLC series resonant converter with a LLT transformer are verified on the simulation based on the theoretical analysis and the 400W experimental prototype.

• Journal of Power Electronics
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• v.7 no.1
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• pp.28-37
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• 2007

A new PWM-controlled quasi-resonant converter for a high efficiency PDP sustaining power module is proposed in this paper. The load regulation of the proposed converter can be achieved by controlling the ripple of the resonant voltage across the resonant capacitor with a bi-directional auxiliary circuit, while the main switches are operating at a fixed duty ratio and fixed switching frequency. Hence, the waveforms of the currents can be expected to be optimized from the view-point of conduction loss. Furthermore, the proposed converter has good ZVS capability, simple control circuits, no high voltage ringing problem of rectifier diodes, no DC offset of the magnetizing current and low voltage stresses of power switches. In this paper, operational principles, features of the proposed converter, and analysis and design considerations are presented. Experimental results demonstrate that the output voltage can be controlled well by the auxiliary circuit using the PWM method.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.1
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• pp.55-69
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• 2016

In response to drastic environmental changes, companies have been continuously rebalancing their resources and capabilities to sustain their competitive status or to survive difficult times. The aim of this study is to analyze the effect of sudden environmental changes on the competitive status of a firm and to identify the internal factors that differentiate sustainer and non-sustainer groups. To achieve this goal, we selected 85 representative IT and non-IT companies from the S&P 500 companies and investigated them with respect to the change in their five-year competitive status since the 2008 global financial crisis. As a concrete performance measure, the concept of perceived competitive status (PCS) was introduced, and four distinct PCS categories were identified by using the stock price changes during the selected period. The four distinct PCS categories are "sustaining," "drifting," "deep sunken," and "bouncing back." Discriminant analysis was performed on these four distinct PCS categories. The empirical study conducted showed that revenue and cost efficiency are the most discriminating factors, especially in the economic recovery period. In particular, stronger financial liquidity was observed in high-performing "bouncing back" companies than in the other category companies.

• Journal of the Korean Society for Heat Treatment
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• v.26 no.6
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• pp.279-287
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• 2013

Oxide Dispersion Strengthened (ODS) Fe with $Al_2O_3$ dispersoid was successfully produced by reactive milling with a mixture of Fe, $Fe_3O_4$ (Magnetite), $Fe_2O_3$ (Hematite) and Al reactants at cryogenic temperature. The milled powders were consolidated by Vacuum Hot Press (HP) at 1323 K, and the consolidated materials were characterized by Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), and Energy Dispersive Spectroscopy (EDS); the yield strength and the hardness of the consolidated materials were determined by compressive test and Vickers hardness test at room temperature. The grain size of the materials was estimated by X-ray Diffraction technique using the scherrer's formula. The TEM observations showed that the microstructure was comprised with a mixture of nanocrystalline Fe matrix and $Al_2O_3$ nano-dispersoids with a bimodal size distribution; the 0.2% off-set yield strength of the materials was as high as $758{\pm}29$ MPa and the Vickers hardness was $358{\pm}2$. The effect of the cryogenic milling and addition of extra Fe powder was discussed on the suppression of MSR (Mechanically induced Self-sustaining Reaction) for the desired microstructural evolution of ODS alloys.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.130-135
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• 2004

This paper describes the development of the dual-thrust rocket motor, which gets a significant change in thrust level by varying the burning area of the propellant grain. Reduced smoke propellant of low burning rate was formulated and the finocyl type grain was designed to get the boosting- and sustaining-phase of the thrust level. And the motor firing data were analyzed in detail. Developed motor was applied to the missile system to implement the successful flight test and this development helped to upgrade the performance of the missile system. The results will be usefully applied to the development of the similar rocket motors.

• Journal of Medicine and Life Science
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• v.16 no.3
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• pp.80-83
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• 2019

First of all, this study shows the legal issues of hospice and palliative care, and the legal basis for lifelong medical practice is generally derived from medical, civil and criminal law regulations, and is applied to patients who are severely ill and dying in principle. In addition, those what is particularly meaningful about hospice and palliative care in terms of legal aspects are discussed the determination of the purpose of care and the provision of medical adaptability and adult guardianship, in particular the legal criteria for the work and status of patient representatives. As such, the purpose of care is to form part of the contract of care and to be agreed between the patient and the physician. In addition, the patient may not write to his/her agent in advance, and the patient may admit discretionary powers to his/her agent, but the patient's will is to be considered. In conclusion, the medical institutional ethics committee should play an active role, especially in the case of no-agents/family or no intention of the patient.