• Journal of the Korea Society of Computer and Information
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• 제21권3호
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• pp.91-96
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• 2016

We have surrounded undesired living noises in our life. One of biggest noises coming out of range hood during cooking in the kitchen. A range hood is one of the most important appliances in the kitchen because it ventilates polluted air out during cooking, and maintains air quality in the kitchen. But current kitchen range hoods bring up some issues; First, the range hoods consume massive amount of standby power not in use condition. Second, current models have designed manual fan operating system with sudden onset of noise with starting. In this paper, we propose an auto control system entire processes from air ventilation to noise reduction. Our system is consist of three parts (Eco-sensors pack, Main Controller and Active Noise Controller); Eco-sensors pack detects air pollution of kitchen areas and sends the detection values to Main Controller. Main Controller determines operation of range hood by detected values. Active Noise Controller is located inside of the range hood. It received starting signals from Main Controller which elicits degrees of polluted air condition and fan operating speed from 1 to 3. Once Active Noise Controller detected the signals, it runs a ventilating fan until new value from Main Controller becomes 0. while the range hood works, A noise cancellation algorithm inside of Active Noise Controller become activated to reduce levels of noise. As a result, the proposed system clearly shows reduction in power consumption include standby power and decreases in levels of noise.

• Journal of the Korean Home Economics Association
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• 제35권2호
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• pp.173-186
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• 1997

The purpose of this study is to find out understand the resident's subjective responses to physical indoor environment. The questionnaire survey was carried out to measure form Jan. 8th to Feb. 2th in 1996, the typical external climate of winter in Korea. The subjects were four hundred and eleven housewives, living in apartments of RC structure I Ilsan apartment complex. As the result, residents usual ventilate once or twice a day by opening outward windows for about ten minutes. Unpleasant smell producted by cooking and wet garbage made most of them negatively respond to kitchen's air quality. regression analysis of relativeness between sense of air freshness smell, dust and comfort revealed that sense of comfort was the most highly related with the extent of bad smell. Housing factors such as size of apartments and ventilating, smoking and gas usage had significant effects on indoor air quality and the subjective responses in winter. Therefore it is especially important to consider air pollution problem from the beginning stage when planning small apartments. It is required that the government of environment has to emphasize the importance of ventilation to residents, and makes an effort to establish the design criteria on indoor air quality in house.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 한국마린엔지니어링학회 2011년도 전기공동학술대회 논문집
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• pp.7-10
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• 2011

According to the requirement of Res.MSC.285(86) for natural gas-fueled engine installations in ships, pump and compressor rooms should be fitted with effective mechanical ventilation system of the under pressure type, providing a ventilation capacity of at least 30 air changes per hour. It generally considered that gas leakage is more likely from a Fueled Gas Supply System(FGS) room as compared to other places, where installed in many kind of machinery or equipments like gas supply high-pressure pipes, valves, flanges and etc. Furthermore, leaked gas may be dispersed in a short time in an enclosed space, especially a FGS room, due to high pressure. However, the present requirement in Res.MSC.285(86) just considers the ventilating capacity of air changes per hour but the capacity of leaked gas. Hence, the current requirements may not meet effectively when enforcing the new propulsion systems as marine fuel. This study is conducted for the purpose of safety evaluation about the dispersion and ventilation efficiency with estimated leakage scenario. Numerical analysis predictions as the result of this paper are explained to know the features of flow pattern and the diffusion of natural gas concentration.

• Journal of the Korean Society of Visualization
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• 제7권1호
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• pp.3-8
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• 2009

Most vehicles have a heating, ventilating and air conditioning (HVAC) device to control the thermal condition and to make comfortable environment in the passenger compartment. The improvement of ventilation flow inside the passenger compartment is crucial for providing comfortable environment. For this, better understanding on the variation of flow characteristics of ventilation air inside the passenger compartment with respect to various ventilation modes is strongly required. Most previous studies on the ventilation flow in a car cabin were carried out using computational fluid dynamics (CFD) analysis or scale-down water-model experiments. In this study, whole ventilation flow discharged from the air vent of a real passenger car was measured using a special PIV (particle image velocimetry) system for large-size FOV (field of view). Under real recirculation ventilation condition, the spatial distributions of stream-wise turbulence intensity and mean velocity were measured in the vortical panel-duct center plane under the panel ventilation mode. These experimental data would be useful for understanding the detailed flow structure of real ventilation flow and validating numerical predictions.

• Journal of KSNVE
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• 제8권5호
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• pp.870-878
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• 1998

The cross-flow fan which constitutes a fan-duct system with a stabilizer and a scroll casing is widely used in many air-ventilating and air-conditioning devices. Its ooperating points of high efficiency and loading conditions frequently induce a annoying sharp tonal component of discrete frequency on the noise spectrum, which is open called as a BPF(Blade-Passing-Frequency) noise and degrades the sound quality of the devices. this BPF tone has been one of the defects of the cross-flow fan. This study proposes two methods in order to reduce this tonal noise component, which are the random distributions of the fan blades and the skewed shapes of the stabilizer. The proposed methods are verified by a simple analytical model and are applied in manufacturing the cross-flow fan and the stabilizer samples. Some experiments are carried out to verify the reduction capability of BPF tones of above two schemes and the experimental results are analyzed. The comparison between two method is also carried out.

• Journal of Institute of Control, Robotics and Systems
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• 제13권7호
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• pp.616-623
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• 2007

A dual micro gas sensor array was fabricated using nano sized $SnO_2$ thin films which had good sensitivities to CO and combustible gases, or $H_2S$ gas for air quality sensors in automobile. The already existed air quality sensor detects oxidizing gases and reducing gases, the air quality sensor(AQS), located near the fresh air inlet detected the harmful gases, the fresh air inlet door/ventilation flap was closed to reduce the amount of pollution entering the vehicle cabin through HVAC(heating, ventilating, and air conditioning) system. In this study, to make $SnO_2$ thin film AQS sensor, thin tin metal layer between 1000 and $2000{\AA}$ thick was oxidized between 600 and $800^{\circ}C$ by thermal oxidation. The gas sensing layers such as $SnO_2$, $SnO_2$(pt) and $SnO_2$(+CuO) were patterned by metal shadow mask for simple fabrication process on the silicon substrate. The micro gas sensors with $SnO_2$(+Pt) and $SnO_2$(CuO) showed good selectivity to CO gas among reducing gases and good sensitivity to $H_2S$ that is main component of bad odor, separately.

• Journal of Environmental Health Sciences
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• 제41권3호
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• pp.216-221
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• 2015

Since Patient Zero of MERS was diagnosed in May 20, 2015, cases of MERS continued to grow. The current situation, which people have been confirmed to be infected, suggested that contaminated indoor air could be the potential cause of hospital-acquired infections. It is important to address the indoor air quality in hospitals because pathogens can spread through air. While the heating, ventilating and air conditioning(HVAC) system is useful managing indoor air quality in hospitals, it can transmit the pathogens if operated improperly. Therefore, it is necessary to remove contaminants in hospitals and operate the HVAC system according to the guidelines, in order to maintain clean indoor air.

• Journal of the Korean Society of Safety
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• 제29권2호
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• pp.1-6
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• 2014

In this paper, safety certification products and safety condition of small transformer is analyzed in industries field and educational facilities. In transformer of 50places, absolute majority is step down transformer to measure of instrument. Most transformers were below 5kVA and 1~3kVA capacity was the mainstream. In industries field, 5 transformers were found without safety certification according to the Electrical Appliances Safety Control Act as cheap product prefer and lack of safety consciousness. Mark & number, voltage, date of manufacture of safety certification must show item of certification. However date of manufacture showed in product of 18%, 9places. As result of thermal imaging camera, running temperature of transformer was showed in below of target temperature. However as a narrow space of transformer and wall, power cable was touched on a ventilating flue in transformer. It was simple carelessness case that surface fouling and temperature ageing of transformer accelerate. Power poor connection, neglect of transformer in production equipment, fall damage by setup incongruity and ground omission were found in case of illogicality item of transformer.

• Journal of Korean Tunnelling and Underground Space Association
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• 제14권6호
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• pp.607-616
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• 2012

The need for management of tunnel air quality is imminent considering the rapid increase of number and span of tunnels in Korea. To investigate spatial distribution of $CO_2$ within tunnels, $CO_2$ were measured and model simulations were performed in Namsan 1 tunnel. Results show that $CO_2$ concentrations were 250 ppm to 400 ppm higher in the exit than tunnel entrance. Also, $CO_2$ concentrations were 200 ppm to 300 ppm lower inside no ventilating vehicle than in the tunnel. Both experimental and model simulation results show that spatial distribution and concentration gradient of air pollutant inside tunnel are highly dependent on traffic density.

• Women's Health Nursing
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• 제18권4호
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• pp.257-267
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• 2012

Purpose: This study was conducted to identify the caring experience of the mothers of childhood burn patients. Methods: Data were collected from 28 mothers of childhood burn patients, through semi-structured in-depth interviews. Data were categorized and coded by using content analysis. Results: 27 categories and 102 statements were drawn from 4 domains. The analyzed domains were psychological sufferings, confronted harsh reality, coping method, and future concerns. Psychological sufferings were categorized heartache, sense of guilt, confusion, regret, depression, sorriness, getting hurt, frustration and upset feeling. Confronted harsh nature were categorized economic difficulty, physical burn-out, lack of caring other children and family troubles. Coping method were categorized positive thinking, having hope, ventilating feelings, accepting the situations, demanding help from family members, changing patterns of the burned child rearing, collecting information for burn treatment, refusing accept the condition of burned child, avoiding personal and social relationship, and reliance on religion. Concerns were categorized concerns of growth and adaptation of the burned child, anxiety for scar, concerns of adapting school life and vague future concerns. Conclusion: The nursing interventions for early assessing psychological problems and providing social supports for caring both burn patients and other siblings should be provided to the mothers of childhood burn patients.