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

• 한국과학기술학회:학술대회논문집
• /
• 2015.12a
• /
• pp.247-278
• /
• 2015

Recently, as DNR prevails more and more in Korea, discussions regarding meaningless medical life-sustaining-treatment (LST) intensified. Some of the Supreme Court decisions are even discussed in mass media, causing public debates. These cases tell us that, as life-sustaining medical technologies are highly developed, more sociological and policy-related analyses are needed on them. Firstly, this study will review 40 previous studies that analyze recent discussions in Korea about LST. Secondly, this study also shows that in bioethical and policy-related perspectives, governance about LST calls for a new implications regarding thanatoethics and thanatopolitics. In this new theoretical framework, death with dignity (DwD) can be understood as a process of giving back the thanatopower to the subject who chooses his way of ending based on his sound and free will. Thirdly, some of the new LST or resuscitation technologies such as automated external defibrillators (AED) are developed in RRI framework. However, if subjects themselves choose not to apply those technologies on them, as in the case of DNR (do not resuscitate) vows, meaning of developing such technologies are to be questioned. But currently such questions regarding the limitations of RRI are seldom asked. I argue that in order to properly apply RRI framework on existing technology, we also need to consider these points.

• Journal of Industrial Convergence
• /
• v.17 no.2
• /
• pp.53-61
• /
• 2019

This study was conducted to explore the effects of Moral Sensitivity(MS), Biomedical Ethics Awareness(BEA) on Attitudes toward Withdrawal of Life-Sustaining Treatment(AWLST) of nursing students. The data were collected from May 1, 2018 to May 20, 2018 for 302 nursing students. The collected data were analyzed using SPSS 22.0. The average degree of MS was 3.45, BEA was 3.69, and AWLST was 3.36. MS was positively correlated with BEA(r=.149, p=.010) and AWLST(r=.223, p<.001). BEA was negatively correlated with AWLST(r=-.129 p=.025). Models including MS(${\beta}=.2.47$, p<.001) and BEA(${\beta}=-.166$, p=.003) explained 7% of variance in the AWLST. It is necessary to provide education that consider the MS, BEA and AWLST level of nursing students to help them establish an acceptable view of AWLST.

• Journal of Power Electronics
• /
• v.5 no.1
• /
• pp.67-75
• /
• 2005

A high efficiency ZVS PWM asymmetrical half bridge converter for a plasma display panel (PDP) sustaining power modules is proposed in this paper. To achieve the ZVS of power switches for the wide load range, a small additional inductor L/sub 1kg/, which also acts as an output filter inductor, is serially inserted into the transformer's primary side. At that point, to solve the problem of ringing in the secondary rectifier caused by L/sub 1kg/, the proposed circuit employs a structure without the output filter inductor, which helps the voltages across rectifier diodes to be clamped at the output voltage. Therefore, no dissipative RC (resistor capacitor) snubber for rectifier diodes is needed and a high efficiency as well as low noise output voltage can be realized. In addition, since it has no large output inductor filter, the asymmetrical half bridge converter features a simpler structure, lower cost, less mass, and lighter weight. In addition, since all energy stored in L/sub 1kg/ is transferred to the output side, the circulating energy problem can be effectively solved. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 425W, 385Vdc/170Vdc prototype are presented.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.723-727
• /
• 2004

A new high-performance and low cost single switch energy recovery display driver for an AC plasma display panel (PDP) is proposed. Since it is composed of only one auxiliary power switch, two small inductors, and eight diodes compared with the conventional circuit consisting of four auxiliary power switches, two small inductors, eight power diodes, and two external capacitors, it features a much simpler structure and lower cost. Nevertheless, since the rootmean-square (RMS) value of the inductor current is very small, it also has very desirable advantages such as n low conduction loss and high efficiency. Furthermore, there are no serious voltage-drops caused by the large gas-discharge current with the aid of the discharge current compensation, which can also greatly reduce the current flowing through power switches and maintain the panel to light at n lower sustaining voltage. In addition, all main power switches are turned on under the zero-voltage switching (ZVS) and thus, the proposed circuit has a improved EMI, increased reliability, and high efficiency. Therefore, the proposed circuit will be well suited to the wall hanging PDP TV. To confirm the validity of the proposed circuit, circuit operations, features,and design considerations are presented and verified experimentally on a 6-inch PDP, 50kHz-switching frequency, and sustaining voltage 141V based prototype.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.537-541
• /
• 2004

A high efficiency ZVS PWM asymmetrical half bridge converter for a plasma display panel (PDP) sustaining power module is proposed in this paper. To achieve the ZVS of power switches for the wide fond range, n small additional inductor $L_{lkg}$, which also acts as an output filter inductor, is serially inserted to the transformer primary side. Then, to solve the problem related to ringing in the secondary rectifier caused by $L_{lkg}$, the proposed circuit employs a structure without the output filter inductor, which helps the voltages across rectifier diodes to be clamped at the output voltage. Therefore, no dissipative RC (resistor capacitor) snubber for rectifier diodes is needed and n high efficiency as well as low noise output voltage can be realized. In addition, since it has no large output inductor filter, it features a simpler structure, lower cost, less mass, and lighter weight. Moreover, since all energy stored in $L_{lkg}$ is transferred to the output side, the circulating energy problem can be effectively solved. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 425W, 385Vdc/170Vdc prototype are presented.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.380-384
• /
• 2005

Plasma display panel (PDP) has a serious thermal problem, because the luminance efficiency of the conventional PDP is about 1.5 lm/W and it is less than $3{\sim}5$ lm/W of cathode ray tube (CRT). Thus there is a need for improving the luminance efficiency of the PDP There are several approaches to improve the luminance efficiency of the PDP and we adopt the driving PDP at high frequency range from 400 kHz up to over 700 kHz. Since a PDP is regarded as an equivalent inherent capacitance, many types of sustaining drivers have been proposed and widely used to recover the energy stored in the PDP. However, these circuits have some drawbacks for driving PDP at high frequency range. In this paper, we investigate the effect of the parasitic components of PDP itself and driver when the reactive energy of panel is recovered. Various drivers are classified and evaluated whether it is suitable for high frequency driver, and finally current-fed type with do input voltage biased is proposed. This driver overcomes the effect of parasitic component in panel and driver and fully achieves ZVS of all full-bridge switches and reduces the transition time of the panel polarity.

• Research in Community and Public Health Nursing
• /
• v.32 no.4
• /
• pp.445-456
• /
• 2021

Purpose: This study was conducted to investigate the effects of a community-based death education program for older adults. Methods: The study was conducted as a quasi-experimental study with a non-equivalent control group and pretest-posttest design. The subjects were community elders aged over 65 registered at a community health center and were convenience sampled. The experimental group consisted of 33 participants and the control group consisted of 32 participants. Experiments are conducted from June 18 to July 24, 2020. We tested our hypothesis using an independent t-test, and paired t-test. Results: The experimental group had significantly higher scores for psychological well-being than the control group after treatment (t=2.24, p=.028). In general attitude toward the use of life-sustaining technology, however, only the experimental group had a significant difference before and after the experiment with lower scores compared to the control group (t=-5.41, p<.001). Conclusion: We found that the community-based death education program developed in this study was partially effective in improving older adults' psychological well-being and general attitude toward the use of life-sustaining technology.

• Journal of Korean Neurosurgical Society
• /
• v.42 no.2
• /
• pp.135-140
• /
• 2007

It is not the best way to treat a hopeless patient with life-sustaining medical devices until the heart beats stop. Advanced medical technology may prolong the life for a significant period without recovery from the disease. However, it would give an unbearable economic burden to the family and the society. In 2006, we decided not to operate 9 patients with traumatic intracranial hematomas. We examined those patients with special references to possible legal and ethical problems. It is reasonable to withhold a treatment after documentation that the family never wants any life sustaining treatment when the treatment does not guarantee the meaningful life.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.9 no.5
• /
• pp.565-575
• /
• 2019

This study aimed to examine the influence of physical environment, microclimate, and comfort on sustaining outdoor activities. This study has identified the main factors that influence sustaining outdoor activities as physical environment, comfort in the physical environment, microclimate and microclimate comfort. For analysis, the study conducted the investigation on pedestrian walkability during spring, summer and winter of the year 2017. The microclimate levels were also recorded at the same time. The method of logit regression analysis was used to analyze these outcomes. The result showed that the comfort and safety of the physical environment as well as the ideal climatic conditions, in terms of temperature, wind level, and solar insolation, were related to sustaining outdoor activities. Also, walking and shopping in the physical and climatic environment were the factors that were found to be more influenced than the act of remaining in a place and forming conversations.