• Journal of Korean Academy of Nursing
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• v.31 no.1
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• pp.31-42
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• 2001

This study was done to evaluate the effect reducing artificial dead space on intubated children. Data were collected from July 1st, 1998 to August 31st, 1999. The subjects were selected from a pediatric intensive care unit of 'S' hospital and intubated with 3.5 mm or 4.5 mm endotracheal tube after open heart surgery. They were composed of 34 patients : 17 patients were assigned to the experimental group and the rest of them were placed in the control group. The artificial airway volume was minimized in the experimental group, and the control group maintained the artificial airway volume. ETCO2, PaCO2, SPO2 were measured as indicators of pulmonary ventilation. The tools of this study were GEM-Premier and Space-Lab patient monitors. The data were analyzed using the SPSS/PC+ program. The $\chi$2 -test was used to find general characteristics. The t-test was used to test the homogenety of the pulmonary ventilation status and mechanical ventilation setting before intervention between the two groups. Also, the paired t-test was used to examine the hypothesis. The results can be summerized as : 1. CO2 can be expelled effectively from the body in case artificial dead space was decreased. 2. As the artificial dead space was reduced, the difference between ETCO2 and PaCO2 was decreased, in other words pulmonary ventilation was improved. 3. If the artificial dead space occupied above 15 percent of tidal volume, the effect of CO2 was retention revealed in the body. 4. If the artificial dead space occupied below effect. Based on the results, the following is suggested to be applied practically : 1. A kind of the ventilator circuit acting artificial dead space should be removed from the intubated children with mechanical ventilaion. 2. The endotracheal tube should not be cut because extra-body space of the endotracheal tube did not have an effect on the dead space of the intubated children. Since the researcher could not cover this aspect in the study, they recommend the following. 1. The study should be extended to the other pulmonary disease patients for the effect of improving pulmonary ventilation. 2. Also, further studying with a more narrow interval in the extra-body space of the artificial airway will be able to explain the point of artificial dead space with proper ventilation.

• Journal of Chest Surgery
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• v.18 no.4
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• pp.771-779
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• 1985

It has been recognized that the proper matching of ventilation and perfusion within the lung is essential for the efficient exchange of gases following open heart surgery. Physiologic shunt reflects the amount of blood going to lung units with inadequate ventilation and these are also areas of the lung with adequate ventilation but inadequate blood flow. This can be quantified by measuring physiological dead space. From January to August 1985, The physiologic dead space and shunt during postoperative course had been taken in 30 patients of open heart surgery in Soonchunhyang University Hospital. Twenty cases had congenital heart disease and acquired valvular heart disease were noticed in 10 cases. The physiological dead space and shunt during postoperative periods were calculated and we made 5 items of conclusion: 1. There is high probability of ventilation-perfusion mismatch in the acquired heart disease group compared to the congenital group. 2. Duration of the CPB can exert significant influences in the physiological dead space but less in the shunt fraction. 3. There is positive relationship between Qs/Qt and Vd/Vt in the group B [CPB>90 min.] but less reliable in correlation. 4. Perfusion impairment is more significant in the diminished pulmonic blood flow group compared to the increased pulmonic blood flow [Qp/Qs>2.0] group. 5. There is no significant ventilation-perfusion mismatch within the lung during all postoperative courses.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.265-269
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• 1994

The switching dead time avoiding a bridge leg short circuit in PWM voltage source inverter produces distortions of the controlling inverter output performance such as current waveform, voltage vector, and torque. In this paper, the influence of dead time is investigated. The on-line space voltage vector modulation method is used for current controller. It is possible to compensate dead time by space voltage vector modulation which generates additional pulse compensating voltage distortion caused by dead time. In addition, narrow pulse which is generally neglected can be compensated. All the algorithms, including field-oriented control are performed by one chip microprocessor 80C196MC and DSP TMS320C31. Experimental results probe that the proposed scheme provides a good inverter output performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.81-82
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• 2009

• Journal of Power Electronics
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• v.15 no.2
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• pp.431-442
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• 2015

Dead-time element must be set into space vector pulsed width modulation signals to avoid short circuits of the inverter. However, the dead-time element distorts the output voltage vector, which deteriorates the performance of electrical machine drive system. In this paper, dead-time effect and its compensation control strategy are analyzed. Based on the analysis, the voltage distortion caused by dead-time is regarded as two disturbances imposed on dq axes in the rotor reference frame, which degenerates the current tracking performance. To inhibit the adverse effect caused by the dead-time, a control scheme using two linear extended state observers is proposed. This method provides a strong ability to suppress dead-time effects. Simulations and experiments are conducted on a permanent magnet synchronous motor drive system to demonstrate the effectiveness of the proposed method.

• 순환기질환의공학회:학술대회논문집
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• 2006.10a
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• pp.32-33
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• 2006

• Journal of Veterinary Clinics
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• v.27 no.3
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• pp.299-301
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• 2010

An acellular human dermal matrix (ADM) was applied to wounds from dogs with significant dead space and delayed healing. This treatment is typically effective for the treatment of wounds with subcutaneous dead space and injuries between muscular planes. The size of the dead space defect and the amount of wound discharge decreased rapidly with ADM treatment in the present study. The average time to disappearance of the dead space defect was 10 days. In addition, complications including severe inflammation were not seen in this case report.

• Proceedings of the KIEE Conference
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• summer
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• pp.1169-1171
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• 2004

Voltage source inverters are required dead time to prevent the short current in the dc link. In recent years, the dead time effect has been investigated in many literatures. This paper presents on the novel space vector PWM inverter without dead time. The proposed inverter don't need to sense load current and to calculate for dead time compensation. Transformers are inserted each leg in the proposed inverter. The proposed method is analyzed each mode and then the simulation results verify the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.4
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• pp.453-459
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• 1995

In this paper, a novel dead time compensation method is presented which produces inverter output voltages equal to reference voltages. An experimental result is also presented to demonstrate the validity of the proposed method. It shows that the compensation of the dead time is possible up to a sub-microsecond range. And the reference voltage can be used as a feedback value, which is essential for sensorless vector control and flux estimation. The method is based on space vector PWM strategy and can be carried out automatically by an inverter controller for initial set-up without any extra hardware.

• KIEAE Journal
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• v.11 no.5
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• pp.31-42
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• 2011

This study aimed at exploring the cultural ways to develope the under-space of overpass in the downtown area which has been considered as a dead, unhealthy place. The study process consists of 4 methodological stages. literature review, case study on environmental design of under-space of overpass, questionnaire and statistical analysis and specific study on regional context were conducted to understand the problems of the space and the needs of the community and visitors. The final suggestion based on the research are the natural rest settings including pocket parks with trees and fountain as well as cultural settings with small sized outdoor gallery and open performance stage which can be managed by the community members. The findings of this study would help the dead space in the center of the city regenerate the community in terms of physical, cultural and social environments. Also, this study will show the importance and the methodological approach of the research for the development of the hidden potential space of the city.