• KIEAE Journal
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• v.2 no.3
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• pp.55-62
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• 2002

While cognition about an environment pollution becomes important recently, the intense pollution measures about an indoor air environment is required. In the case of building indoor environment, over 80% of modem people is living in building and these days an interest of building interior materials which becomes a reason for indoor environmental pollution in public house, office, is increasing. An experimental measurement method of this study is as follows. (1) American EPA TO-17, ASTMD5116-97, measurement method in VOCs experiment of Japanese closet industrial association (2) 2.4-DNPH cartridge method in HCHO experiment, based on American EPA TO-11 and measurement method of Japanese closet industrial association (3) standard compound is analyzed by using HPLC after solvent extraction process (4) paint and furniture are selected as measurement objects (5) we also made small chamber to grasp an emission characteristic of HCHO and VOCs and to get an environment-amicable forecast model through it, then we developed the model which can forecast emission rate by chamber experiment.

• KIEAE Journal
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• v.9 no.1
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• pp.85-90
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• 2009

The indoor air quality is one of the most important issues of designing ventilation in high rise apartment buildings. This study suggested proper ventilation rate in the apartment bedroom where mechanical ventilation system has installed. Six university students(four male and two female) were participating in the experiment. Experiments were performed in environmental chamber. Experimental conditions were combinations from three ventilation rate 0, 0.4 and 0.7. Measurement items during 8 hours of experimental time were temperature, humidity, carbon dioxide concentrations and questionnaire surveyed aftrer sleeping. The concentration of Carbon Dioxide depending on ventilation rate in the chamber was analyzed for proper ventilation rate. The results of this paper can be summarized as follows. (1) When two persons experiment, 0.7 ventilation rate was in excess of 1000ppm. (2) When one person experiment, 0.7 and 0.4 ventilation rates were satisfied the criteria of IAQ. (3) It compared 0.4 with 0.7 in the ventilation rate, 0.4 ventilation rate could reduced about 80% of the power by fan similarity law.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.447-452
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• 2009

The objectives of this paper are to study the effects of thermal and geometric conditions on the performance of indoor heat exchanger with R410A. This study carried out experimental and numerical analysis for indoor heat exchangers. In the experimental study, capacity of the indoor unit was estimated 8.3 kWh with the valve opening rate of 95% for the 50% partial operation condition. The air temperatures were measured using 80 thermocouples. This study also compared experimental data with the calculated data for the outlet temperature and the tube length. It is found that the relative errors between the experiment data and the calculated result are 4.2% and 0.5% for the outlet temperature and the tube length, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.226-227
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• 2018

Recently, as the interest of the government and the public on energy saving has increased, the airtightness of buildings has been improved to improve the insulation performance of buildings. However, indoor air pollution due to increase of pollution source in indoor space and lack of ventilation is increasing and interest in indoor air quality is increasing. In 2003, the Ministry of Environment enacted and promulgated the Act on Indoor Air Quality Control in Multi-use Facilities. Radon is a naturally occurring radioactive inert gas with colorless, tasteless and odorless nature. The concentration is high in a room where radon can not escape. Although lononggas is naturally occurring, it is not interested in living environment, but it is easily inhaled through human body through respiration and causes lung cancer in long-term exposure. Therefore, this study intends to carry out an experiment for the reduction of radon gas, which is the first carcinogen in indoor air pollution sources.

• KIEAE Journal
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• v.10 no.6
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• pp.67-72
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• 2010

This study was conducted to examine the change of heating environment with the creation of an indoor water space. Living environments and comfort of dwellers can be improved by utilizing the physical properties of water effectively. This study focuses on the basic examination of the effect of water space and the environmental effects of water space by experiment. Two identical models were fabricated to compare the changes in indoor temperature and humidity with and without a water space. With the water space, temperature was reduced by an average of $0.55^{\circ}C$ a day and moisture content increased by an average of 4%. As a result, it was possible to obtain quantitative data on water space's temperature reduction and humidity control capacities. This study is expected to provide basic information for further studies on the effect of water spaces in various buildings.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.5
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• pp.195-200
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• 2021

In this paper, we propose a method for a mobile robot to estimate a specific location of a service provision target using a beacon-tag for the purpose of providing location-based services (LBS) to users in an indoor environment. To estimate the location, the irregular characteristics and error factors of the received signal strength indicator (RSSI) generated from the beacon are analyzed, and the distance conversion function is derived from the RSSI data extracted by applying a Gaussian filter. Then, the distance data converted from the plurality of beacons estimates an indoor location through a triangulation technique. After that, the improvement in the location estimation is analyzed by applying the temporal confidence reasoning technique. The possibility of providing a LBS of a mobile robot was confirmed through a location estimation experiment for a plurality of designated locations in an indoor environment.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.1
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• pp.45-49
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• 2022

In this paper, we propose a method for estimating the error of the Ultra-Wideband (UWB) distance measurement using the channel impulse response (CIR) of the UWB signal based on machine learning. Due to the recent demand for indoor location-based services, wireless signal-based localization technologies are being studied, such as UWB, Wi-Fi, and Bluetooth. The constructive obstacles constituting the indoor environment make the distance measurement of UWB inaccurate, which lowers the indoor localization accuracy. Therefore, we apply machine learning to learn the characteristics of UWB signals and estimate the error of UWB distance measurements. In addition, the performance of the proposed algorithm is analyzed through experiments in an indoor environment composed of various walls.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.717-720
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• 2020

An indoor localization system that uses Wi-Fi RSSI signals for localization gives accurate user position results. The conventional Wi-Fi RSSI signal based localization system uses raw RSSI signals from access points (APs) to estimate the user position. However, the RSSI values of a particular location are usually not stable due to the signal propagation in the indoor environments. To reduce the RSSI signal fluctuations, shadow fading, multipath effects and the blockage of Wi-Fi RSSI signals, we propose a Wi-Fi localization system that utilizes the advantages of Wi-Fi RSSI heat maps. The proposed localization system uses a regression model with deep convolutional neural networks (DCNNs) and gives accurate user position results for indoor localization. The experiment results demonstrate the superior performance of the proposed localization system for indoor localization.

• Journal of Environmental Impact Assessment
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• v.14 no.4
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• pp.147-155
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• 2005

This study was designed to investigate the effect of plant as a botanical air purification on the indoor pollution by formaldehyde. Three indoor plants such as Dracaena marhginata, Spathiphyllum and Dracaena reflexa, were placed in the artificially contaminated reactor under laboratory condition. Both plant and soil effects on removal of formaldehyde from contaminated indoor air were observed. Reductions in the formaldehyde levels appeared to have been associated with soil medium factors as well as plant factors. The effect of soil on formaldehyde reduction was high in the early stage of the experiment and the results suggest that sorption could be more important factor than microbial degradation in the initial dissipation of contaminants in the soil. It was suggested that the effect of plant on formaldehyde reduction might be related to the plant species, total leaf surface area of plant, degree of contribution of soil medium, and exposed concentration level. The results of this study showed that air purification using plants is an effective means of reduction on indoor formaldehyde level, though, utilization of soil media with high sorption capacity and/or supplementary purifying aids were also suggested when the source is continuous or exposed concentration level is high.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.330-333
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• 2003

In this thesis. the application of the synchronizing control of the intelligent indoor lift system is showed. The separate axes of the indoor lift system are driven independently. PID controller, synchronous flexible logic compensating method and tilt sensor are applied to enhance the performance of the intelligent indoor lift system. the tilt sensor senses the horizontal error of the whole system. PID controller and synchronous flexible logic are used to compensate the synchronous errors of both the separate axes and whole system to be zero. Namely, using not the hardware coupling but the software algorithm. the indoor life system is operated without the error. Before applying the real system, the simulation using matlab testifies the possibility of the lift system. And the realization of the system is demonstrated with two DC servo motors. In the experiment test, flexible logic to compensate the synchronous error is chosen by the comparative method. the indoor lift system has to be considered the loading factor as the disturbance. Because the intelligent indoor lift system is developed to support the patients who don't change for themselves to move. finally, the system which considers the weight of the patient as the disturbance can carry the patients safely without synchronous and position error.