• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.466-474
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• 2014

According to wireless network technology and mobile processors performance were improved, the small wireless mobile device such as smart phones has been widely utilized. The mobile devices can be used GPS information, thereby the services based on location information was increased. GPS was impossible to provide location information in indoor and signal shading environment, and the tracking systems based on short distance wireless communication are required infrastructure. The IEEE 802.11 based tracking system is possible estimation using APs, however the tracking device is exhausted battery power seriously. In this paper, we propose IEEE 802.11 based low-power tracking system. We reduced power consumption from channel scanning and network connection. For performance evaluation, we designed and implemented the tracking tag device, and measured power consumption of the device. As the simulation result, we confirmed that the power consumption was reduced 46% compare to the standard execution.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.5
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• pp.265-278
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• 2021

When a dangerous event arises for people inside a building and an immediate evacuation is required, it is important that suitable routes have been previously defined. These situations can happen especially when buildings are crowded, making the occupants have a very high vulnerability and can be trapped if they do not evacuate quickly and safely. However, in most cases, routes are considered based just on their proximity or short distance to the exit areas, and evacuation simulations that include more variables are not performed. This work aims to propose a methodology for building's indoor evacuation activities under the premise of processing simulation scenarios in multi-agent environments. In the methodology, importance indexes of simplified and validated geometry data from a BIM (Building Information Modeling) are considered as heuristic input data in a proposed algorithm. The algorithm is based on AP-Theta^* pathfinding and collision avoidance machine learning techniques. It also includes conditioning variables such as the number of people, speed of movement as well as reaction ability of the agents that influence the evacuation times. Moreover, collision avoidance is applied between people or with objects along the route. The simulations using the proposed algorithm are tested in NetLogo for diverse scenarios, showing feasible evacuation routes and calculating evacuation times in a multi-agent environment. The experimental results are obtained by applying the method in a study case and demonstrate the level of effectiveness of the algorithm, and the influence of the conditioning variables analyzed together when performing safe evacuation routes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.3
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• pp.448-458
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• 2020

Indoor positioning based on trilateration using common chord estimates location of a mobile subject by using intersection points between each circles which the radius is same as distance between the mobile subject and each radio-frequency transmitter. However, if the intersection points are not found due to error of the distance measurement, it causes failure of estimating the mobile subject's location. To prevent this case, numbers which is proportionate to radius of each circles, are temporarily added to each distances in order to lengthen radius of the circles. Although the estimated location includes error due to the radius extension, it is corrected again by the added value and distance from reference point. With introduction of the advanced correction algorithm, potential issues of existing trilateration such as failure of estimating location and distance measurement error will be minimized.

• Journal of Naturopathy
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• v.11 no.1
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• pp.18-30
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• 2022

Background: It was to develop an air purification system (APS) using an underground air purification layer to verify the effect of basalt forest's underground air (sumgol) on a volcanic Jeju. Finally, it is necessary to analyze these purified air components and their usefulness to the human body in an air experience center. Purpose: It was to collect basalt forest air, analyze its composition, and explore its effect on the human body. Methods: We APS devices installed at four points in the Papaville area of Jeju. The air discharged from the APS was collected and analyzed the recycling components. An installed experience room filled with negative ions is about 5,000 ions/m³. After allowing the participants to stay for 60 to 120 minutes, we investigated the state of blood vessels. Results: In the analysis of the underground air, the O₂ concentration was 21.18%, which was higher than the average oxygen concentration of 20.94% in the atmosphere. However, Formaldehyde was not detected, and the CO₂ was 419 ppm, which was lower than that of indoor air. The PM2.5 concentration was less than 24 ㎍/m³ and detected anions over 5.000 /m³. The experiencer's vascular states improved, and the increase in pulse rate and stress relief were high. Conclusions: The valuable ingredients identified by analyzing the air were precious for natural healing. The experience results showed that it effectively improved the pulse rate, blood vessels, and stress. These conditions may be highly beneficial as a new area for expanding the basalt lava forest in the Jeju area into the natural healing and wellness industry.