• Journal of Institute of Control, Robotics and Systems
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• v.21 no.4
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• pp.378-384
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• 2015

Indoor localization is becoming one of the most important technologies for smart mobile applications with different requirements from conventional outdoor location estimation algorithms. Fingerprinting location estimation techniques based on neural networks have gained increasing attention from academia due to their good generalization properties. In this paper, we propose a novel location estimation algorithm based on an ensemble of multiple neural networks. The neural network ensemble has drawn much attention in various areas where one neural network fails to resolve and classify the given data due to its' inaccuracy, incompleteness, and ambiguity. To the best of our knowledge, this work is the first to enhance the location estimation accuracy in indoor wireless environments based on a neural network ensemble using fingerprinting training data. To evaluate the effectiveness of our proposed location estimation method, we conduct the numerical experiments using the TGn channel model that was developed by the 802.11n task group for evaluating high capacity WLAN technologies in indoor environments with multiple transmit and multiple receive antennas. The numerical results show that the proposed method based on the NNE technique outperforms the conventional methods and achieves very accurate estimation results even in environments with a low number of APs.

• Spatial Information Research
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• v.16 no.4
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• pp.455-465
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• 2008

Augmented reality (AR) has tremendous potential in visualizing geospatial information, especially on the actual physical scenes. However, to utilize augmented reality in mobile system, many researches have undergone with GPS or ubiquitous marker based approaches. Although there are several papers written with vision based markerless tracking, previous approaches provide fairly good results only in largely under "controlled environments." Localization and tracking of current position become more complex problem when it is used in indoor environments. Many proposed Radio Frequency (RF) based tracking and localization. However, it does cause deployment problems of large RF-based sensors and readers. In this paper, we present a noble markerless AR approach for indoor (possible outdoor, too) navigation system only using monoSLAM (Monocular Simultaneous Localization and Map building) algorithm to full-fill our grand effort to develop mobile seamless indoor/outdoor u-GIS system. The paper briefly explains the basic SLAM algorithm, then the implementation of our system.

• Journal of KIISE
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• v.44 no.7
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• pp.733-741
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• 2017

LPWAN(Low Power Wide Area Network) technology is M2M (Machine to Machine) networking technology for the Internet of Things. The technology is designed to support low-power, long-distance and low-speed communications that are typical of LoRaWAN(Long Range Wide Area Network). To exchange inter-object information using a LoRaWAN, the link performances for various environments must be known. however, active performance analysis research that is based on an empirical environment is nonexistent. Therefore, this paper empirically evaluates the performance of the LoRa (Long Range) link, a physical communication technology of the LoRaWAN for various variables that may affect the link quality in indoor and outdoor environments. To achieve this, a physical performance monitoring system was designed and implemented. A communication experiment environment was subsequently constructed based on the indoor and outdoor conditions. The SNR(Signal to Noise Ratio), RSSI(Received Signal Strength Indication), and the PDR(Packet Delivery Ratio) were evaluated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.524-539
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• 2014

To investigate schemes of secret key generation from Ultra-wideband (UWB) channel, we study a statistical characterization of UWB outdoor channel for a campus playground scenario based on extensive measurements. Moreover, an efficient secret key generation mechanism exploiting multipath relative delay is developed, and verification of this algorithm is conducted in UWB Line-of-sight (LOS) outdoor channels. For the first time, we compare key-mismatch probability of UWB indoor and outdoor environments. Simulation results demonstrate that the number of multipath proportionally affects key generation rate and key-mismatch probability. In comparison to the conventional method using received signal strength (RSS) as a common random source, our mechanism achieves better performance in terms of common secret bit generation. Simultaneously, security analysis indicates that the proposed scheme can still guarantee security even in the sparse outdoor physical environment free of many reflectors.

• Journal of Life Science
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• v.22 no.8
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• pp.1085-1091
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• 2012

The purpose of this study is to investigate the effects of indoor and outdoor exercise environments on bone mineral density and body composition in old women. A total of 26 old women were randomly divided into two groups: an indoor exercise group (IE, n=13) and an outdoor exercise group (OE, n=13). The exercise groups performed moderate exercise (HR max 50~70%; RPE 11-15) three times a week for 60 minutes over 20 weeks. After exercise training, bone mineral density was significantly improved in the OE group as compared with the IE group. Body fat mass was significantly decreased in the IE group. Weight, lean body mass, and body fat mass were significantly decreased in the OE group. Body mass index was significantly decreased in the outdoor exercise group as compared to the IE group. Our findings show that a 20-week program of outdoor exercise training improves bone mineral density and body composition in old women. As mentioned above, it has been found that engaging in an outdoor exercise program for 20 weeks has a positive effect on bone mineral density and body composition in old women. In conclusion, engaging in the outdoor exercise program, including aerobic and resistance exercises, for 20 weeks improved bone mineral density and inhibited bone loss in old women and had a positive influence on vitamin D levels, thereby potentially lowering the risk of osteoporosis.

• Journal of the Ergonomics Society of Korea
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• v.34 no.3
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• pp.265-278
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• 2015

Objective:To study the sources of indoor noise, its effects on human health, noise assessment and regulation through the use of standards, and techniques used to reduce noise. Background: Noise significantly affects the living environment, and there are an increasing number of reports of its impacts on human health. Method: We reviewed domestic and foreign data regarding environmental noise, and examined its effects and the standards used to regulate noise levels. Results: We describe the major sources of indoor noise and suggest possible legal standards, as well as recommended criteria for the control of noise. Conclusion: South Korea has higher legal standards of environmental noise than international standards in terms of threshold values. People in Korea are exposed to various sources of noise, and therefore the reduction of noise is urgently required. Application: Depending on the features of indoor spaces, an appropriate degree of indoor noise can be determined and techniques to reduce excess noise are required.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.273-277
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• 2009

This study was conducted to develop standards for evaluating what extant the physical environments of housing which can cope with the needs of the aging society. This study was consisted through literature investigation research mainly, and research target literature limits keyword to elderly housing environment and chose connected domestic various literatures. The scope of evaluation was limited to the indoor spaces and outdoor spaces of housing as it was thought that the elderly spend much more time at indoor, outdoors, considering their physical characteristics. The study are as follows ; First, in outdoor only area from design environment element accessibility, and safety emphasized from equipment element, health of community territory was expose from design environment element that supportiveness is emphasized from equipment element. Second, in living room safety emphasized from design environment element in bedroom and bathroom of indoor individuation space, vestibule, balcony supportiveness, health was expose that is emphasized kitchen and mess. Also, was expose that supportiveness is emphasized from equipment element of all individuation spaces. Third, was expose that design environment element in corridor that is indoor official business space, stair, lobby, elevator and safety from equipment element and supportiveness are emphasized.

• Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.250-265
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• 2016

Owing to our rapidly aging society, accessibility evaluation to enhance the ease and safety of access to indoor and outdoor environments for the elderly and disabled is increasing in importance. Accessibility must be assessed not only from the general standard aspect but also in terms of physical and cognitive friendliness for users of different ages, genders, and abilities. Meanwhile, human behavior simulation has been progressing in the areas of crowd behavior analysis and emergency evacuation planning. However, in human behavior simulation, environment models represent only "as-planned" situations. In addition, a pedestrian model cannot generate the detailed articulated movements of various people of different ages and genders in the simulation. Therefore, the final goal of this research was to develop a virtual accessibility evaluation by combining realistic human behavior simulation using a digital human model (DHM) with "as-is" environment models. To achieve this goal, we developed an algorithm for generating human-like DHM walking motions, adapting its strides, turning angles, and footprints to laser-scanned 3D as-is environments including slopes and stairs. The DHM motion was generated based only on a motion-capture (MoCap) data for flat walking. Our implementation constructed as-is 3D environment models from laser-scanned point clouds of real environments and enabled a DHM to walk autonomously in various environment models. The difference in joint angles between the DHM and MoCap data was evaluated. Demonstrations of our environment modeling and walking simulation in indoor and outdoor environments including corridors, slopes, and stairs are illustrated in this study.

• Tuberculosis and Respiratory Diseases
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• v.86 no.1
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• pp.23-32
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• 2023

Everyone is aware that air and environmental pollutants are harmful to health. Among them, indoor air quality directly affects physical health, such as respiratory rather than outdoor air. However, studies that have examined the correlation between environmental and health information have been conducted with public data targeting large cohorts, and studies with real-time data analysis are insufficient. Therefore, this research explores the research with an indoor air quality monitoring (AQM) system based on developing environmental detection sensors and the internet of things to collect, monitor, and analyze environmental and health data from various data sources in real-time. It explores the usage of wearable devices for health monitoring systems. In addition, the availability of big data and artificial intelligence analysis and prediction has increased, investigating algorithmic studies for accurate prediction of hazardous environments and health impacts. Regarding health effects, techniques to prevent respiratory and related diseases were reviewed.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1691-1710
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• 2020

We measured PM2.5 and PM10 (particulate matter less than 2.5 ㎛ and 10 ㎛ in diameter, respectively) simultaneously at 16 locations around an elementary school and classrooms in Busan and Pyeongtaek, South Korea. In this study, we compared the results of this field intensive with those in the literature (144 cases of 30 studies), focusing on I/O (Indoor/Outdoor) ratios. We also reviewed the results of previous studies, categorizing them into related sub-categories for indoor-activities, seasons, building-uses, and the surrounding environment. We conclude that indoor PM10 is affected more by indoor-sources (e.g., physical activities) than PM2.5 in the absence of combustion sources like smoking and cooking. Additionally, PM10 and PM2.5 likely have different indoor-outdoor infiltration efficiencies. Conclusively, PM10 in classrooms can be more sensitively affected by both indoor activities and ambient concentrations, and mechanical ventilation can be more efficient in reducing PM concentrations than natural ventilation.