• Wind and Structures
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• v.21 no.3
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• pp.331-352
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• 2015

A series of wind tunnel tests were conducted on tapered super high-rise buildings with a square cross section by applying synchronous pressure measurement technology. The effects of global strategy of chamfered modification on aerodynamic loads and wind-induced responses were investigated. Moreover, local aerodynamic strategies of opening a ventilation slot in the corner of equipment and refuge floors were carried out. Results show that the global strategy of tapered elevation increased the vortex shedding frequency, but reduced vortex shedding energy, leading to reduction of across-wind aerodynamic loads and responses. Chamfered modification suppressed the across-wind vortex shedding effect on tapered buildings. Opening the ventilation slot further suppressed the strength of vortex shedding and reduced the residual energy related to vortex shedding in aerodynamic loads of chamfered buildings. Finally, the optimized locations of local aerodynamic strategies were suggested.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.5
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• pp.910-920
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• 2016

This study is to understand the problems of current police raincoats for professional policemen and conscripted policemen. Interviews and a survey were completed to investigate the wearing conditions of current police raincoats. The questionnaire was composed of questions on current wearing conditions of raincoat, motional adaptability, dimensional compatibility, design suitability and demographic information on the research target. The results indicated that the wearing frequency of raincoats had significant difference according to duty and age range. The main reason for the low wearing frequency was the uncomfortableness of working while wearing the raincoat, followed by the inconvenience of managing the raincoat after use and feeling hot while wearing the raincoat. The three most important factors when wearing a raincoat was pleasantness, activity capability and the functionality of the fabric. The satisfaction on body parts during motions tended to be evaluated lower as the raincoat size increased. The results of the dissatisfaction factors indicated that the raincoat hood had the most problems. There was inconvenience when using the equipment belt because officers have to wear their belts inside the raincoat. In regards to the fabric satisfaction level, respondents were less satisfied with ventilation, hygroscopicity, and drying time. Therefor it appeared that the current raincoat had problems due a lack of functionality in regards to ventilation, hygroscopicity, and quick drying; in addition, the satisfaction on motional adaptability had a significant difference according to raincoat size.

• Fashion & Textile Research Journal
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• v.16 no.3
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• pp.421-433
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• 2014

The aim of this study was to provide compression wear manufacture brands with information needed for product development. 8 tops and 7 bottoms from widely recognized compression wear manufacture brands were selected, and their product structural elements were analyzed, too. The results showed that most compression wear designs were applications of cutting lines designed considering muscle movements of the human body. The average number of cutting lines for patterns and designs were 14 for tops and 15 for bottoms. Different colored material was mainly used on the top for areas that require ventilation or high movement during sports for tops, and for areas that require muscle and joint support during sports for bottoms. The functionality of top materials were found to be stretch, muscle support, moisture absorption and high speed drying, warmth and ventilation for tops, in order of frequency, and stretch, muscle support, moisture absorption and high speed drying, and pressure for bottoms, in order of frequency. Tops were cut in the direction of the lengthwise grain, and bottoms were not only cut in the direction of the lengthwise grain, but also in the direction of the crosswise grain and bias for many products. Tops consisted of an average of 13 organically connected panels, and bottoms consisted of an average of 18 organically connected panels, which was analyzed to improve functionality. The average clothing surface area stretch rate was 85.7% for tops and 70.0% for bottoms, indicating that bottoms were designed to have higher strain rates compared to tops.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.3
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• pp.232-239
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• 2022

This study performed qualitative and quantitative risk assessment of equipment for evaluating the protocol of hydrogen refueling stations and suggested measures to improve safety. Hazard and operability study was performed for qualitative risk assessment, and Hy-KoRAM was used for quantitative risk assessment. Through a qualitative risk assessment, additional ventilation devices were installed, simultaneous venting of the storage container was prohibited, and the number of repeated refilling of the evaluation equipment was identified to manage the number of fillings of the container. Through quantitative risk assessment, the area around the device was set as a restricted area when evaluating the station, and measures were suggested to reduce the frequency of accidents.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.191-196
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• 2016

Applying diffraction of waves and muffler principle, the theory of macroscopic air ventilation with soundproofing was explained. Soundproofing frequency range can be selected by this method. The sound wave was attenuated at the resonator located between double-layered walls. A soundproof plate was designed and the experiment was processed. There are two air holes of diameter of 5cm and thickness of 8cm on the surfaces per each soundproofing cell. There was a transmission loss of about 25dB and it is more than at least 10dB compared with that of the Comnex technology of wave cancellation by air holes in Japan. Furthermore, there was no soundproof frequency selection in the Comnex technology.

• Tuberculosis and Respiratory Diseases
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• v.79 no.4
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• pp.214-233
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• 2016

There is no well-stated practical guideline for mechanically ventilated patients with or without acute respiratory distress syndrome (ARDS). We generate strong (1) and weak (2) grade of recommendations based on high (A), moderate (B) and low (C) grade in the quality of evidence. In patients with ARDS, we recommend low tidal volume ventilation (1A) and prone position if it is not contraindicated (1B) to reduce their mortality. However, we did not support high-frequency oscillatory ventilation (1B) and inhaled nitric oxide (1A) as a standard treatment. We also suggest high positive end-expiratory pressure (2B), extracorporeal membrane oxygenation as a rescue therapy (2C), and neuromuscular blockage for 48 hours after starting mechanical ventilation (2B). The application of recruitment maneuver may reduce mortality (2B), however, the use of systemic steroids cannot reduce mortality (2B). In mechanically ventilated patients, we recommend light sedation (1B) and low tidal volume even without ARDS (1B) and suggest lung protective ventilation strategy during the operation to lower the incidence of lung complications including ARDS (2B). Early tracheostomy in mechanically ventilated patients can be performed only in limited patients (2A). In conclusion, of 12 recommendations, nine were in the management of ARDS, and three for mechanically ventilated patients.

• Clinical and Experimental Pediatrics
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• v.48 no.4
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• pp.401-405
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• 2005

Purpose : The use of mechanically-assisted ventilators at home reduces morbidity and improves the quality of life in children with chronic respiratory failure. But in Korea there is no clinical data of children with home mechanical ventilation. We investigated ventilator types, duration, the causes of failure or death, and the cost needed for care. Methods : We retrospectively analyzed the medical records of 21 children who were admitted and who applied for home mechanical ventilation at the Pediatric Intensive Care Unit in Asan Medical Center. Phone interviews took place after discharge. and interviewed by phone after discharge. Results : The median age was 31 months; the median duration with ventilator was 25 months. Underlying diseases were 16 neuromuscular diseases, one metabolic disease and four chronic respiratory diseases. The types of ventilator were pressure and volume type(16 and five patients, respectively). The frequency of ventilation failure was once per 19 months. Weaning could be performed in three cases. Frequencies of admission after receiving ventilators were 1.7 times per year; the most common cause was pneumonia. Nine patients(43%) died; four of them died because of endotracheal tube obstruction. The costs for medical care were about 1,110,000 won per month. Conclusion : There is an increment in the numbers of individuals who need mechanical ventilation support. The most common cause of death was endotracheal tube obstruction. The most important problem for the patients was medical cost. There needs to be more interest in patients with ventilator and social welfare systems to support their families need to be prepared.

• Clinical and Experimental Pediatrics
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• v.46 no.11
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• pp.1073-1079
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• 2003

Purpose : Recently there has been a decrease in ventilator care rate and duration of very low birth weight infants(VLBWI) in Fatima Hospital. The aims of this study were to survey the frequency and duration of ventilation in VLBWI and to develop a non-invasive neonatal intensive care unit (NICU) policy. Methods : We performed a retrospective study of 284 newborn of infants less than 1,500 gm admitted to NICU and discharged from January 1998 to December 2001. Patients were intubated or applied continuous positive airway pressure(CPAP) via nasal prong immediately after presenting signs of respiratory distress. We analyzed epidemiologic data to study the changes in ventilator care rate, duration and outcome of ventilator care groups. Results : Of 284 newborn infants, 146 required invasive management, such as endotracheal intubation and assisted ventilation. The characteristics, the severity of clinical symptoms and laboratory findings in ventilator care groups at birth showed no significant differences. The annual proportion of infants requiring assisted ventilation decreased according to increasing gestational age. The median duration of ventilation decreased markedly from 6.0 days in 1998 to 2.7 days in 2001. Final complications and outcomes in ventilator care groups showed no significant differences. Conclusion : Our study shows a significant reduction in the invasiveness of the treatment of VLBW infants, which was not associated with an increased mortality or morbidity. A non-invasive strategy for the VLBW infant with minimal to moderate respiratory distress after birth in NICU is better than immediate invasive management. Non-invasive nasal CPAP is a simpler and safer method than invasive assisted ventilation.

• Fire Science and Engineering
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• v.33 no.6
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• pp.53-62
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• 2019

A recent trend shows that more buildings are being constructed as mixed-use (residential and commercial) properties for efficient land use. This has led to an increased frequency in the occurrence of fires and the associated potential risks. In particular, in case of high-rise apartments, at least one of the elevators in each building is installed for evacuation purposes separately from the emergency elevator; therefore, for a combined ancillary room and emergency elevator platform situation, the structure is inevitably in series with the evacuation elevator platform. Thus, a proposal for a new type of ventilation zone based on existing national fire safety codes is required to achieve smoke control performance. To this end, the air egress velocity and differential pressure of each ventilation zone are checked using the "CONTAM" software; further, an alternative is proposed to secure smoke control performance for series structures.

• Journal of Yeungnam Medical Science
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• v.5 no.1
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• pp.105-110
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• 1988

The study was undertaken to determine the most adequate tidal volume when used volume preset ventilator during anesthesia. The thirty patients were received controlled mechanical ventilation with constant inspiratory pressure of 10cmH2O and respiratory frequency of 12/minute. The results were as follows : 1) The PH was $7.39{\pm}0.01$ and it is within normal limit. 2) The $PaCO_2$ was $34.0{\pm}0.6$ mmHg and it is a slightly hyperventilatory state. 3) The $PaO_2$ was $228.0{\pm}8.2$ mmHg. 4) The Buffer base was $20.7{\pm}0.3mEql$ and it is a slightly buffer base deficient state. From the above results. We concluded that if patients were fully relaxed during general anesthesia, it is desirable to maintain the inspiratory pressure of anesthetic mechanical ventilator to $10cmH_2O$ for adeguate alveolar ventilation.