• Journal of Environmental Health Sciences
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• v.41 no.2
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• pp.61-70
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• 2015

Objectives: The purpose of this research was to examine radon exposure in terms of the relationship between the living environment and indoor radon concentrations among vulnerable households. Methods: Nationwide, 1,129 subjects were selected using personal questionnaires for adequately understanding the living environment, installation of E-PERM radon gas detectors, and investigation of the structure of the housing. Results: The mean concentration of indoor radon for all subjects was $130.2Bq/m^3$ (GM=101.7), and a total of 438 subjects (38.8%) exceeded the recommended standards ($148Bq/m^3$) for public facilities by the Ministry of the Environment. By location, the highest concentrations ($164.3Bq/m^3$, GM=124.1) were seen in North Chungcheong Province. In the case of the Seoul/Gyeonggi Province metropolitan area, they showed $125.6Bq/m^3$ (GM=105.1) and $118.9Bq/m^3$ (GM=96.5), respectively. By type of housing, indoor radon concentrations in single-family housing were higher than in row/multi-family housing (p<0.01). Although indoor radon concentrations raised in accordance with year of construction (p<0.05), the difference between indoor radon concentrations in underground residences was not observed to be statistically significant (p=0.633). Conclusion: More studies are necessary in the future regarding the difference in indoor radon concentrations that may occur due to different of types of indoor construction, building materials, and the amount of building materials.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.833-838
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• 2011

RFID system in manufacturing industry is used to collect, categorize, and process the data of products. To install RFID system for a large factory, a large amount of wired data communication network is necessary for RS232 communication. If the installed location of RFID system in the factory is changed or extended, a reinstallment is required for the already installed wired data network. A large amount of time/financial reinvestment is necessary for such reinstallation. By using wireless data communication network, however, the initial installation and reinstallation are very simple. In this paper, we implemented a wireless communication system and RFID system. We used the CC1020 chip for wireless communication system and EM4095 chip for RFID system. CC1020 chip enables highly-reliable data communication, and by setting a simple status register, it can switch between transmitting/receiving status and it can choose the desired frequency of either 400 MHz or 900 MHz. Also, Communication range is 50 m, if external antenna is used. EM4095 is a chip for RFID reader system with the carrier frequency of 125 KHz. This chip can implement the reader system by connecting a small number of components. And EM4100 was used for RFID system. EM4100 is read-only type. Atmega128 is used to control a wireless communication system and RFID system. We confirm that the system can communicate without error up to 50 m from sender. In the paper, the circuit diagram and operation program for CC1020 and RFID system are presented. The system used in the experiment is shown in pictures, and the data movement pattern of CC1020 is shown in the diagram, and the performance of each transmission method is presented.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.629-636
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• 2017

Urban railway are the most widely used means of transportation in the metropolitan area. It is difficult to draw out problems through the quantitative analysis technique because most of the research results show that most of the guide signs are installed with many or few guide signs. In this study, we propose a method to evaluate the information load and proper installation location at the main decision point in the transfer passageway for Suseo Station by applying Positive Guidance. As a result of analyzing the information load using this technique, it is suggested that the necessary information should be provided centered on the copper node because it provides confusion of the users by providing the same information in the transfer line. It is necessary to obtain guidance on how to remove the sign (advertising, high ceilings, etc). The study will be regarded as a key for the basis and placement of the guidelines for determining the appropriateness of the in the future urban railway station sign guide.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.501-511
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• 2018

As a result of the recent revision of the 'Guideline for Installation and Management of Fire Prevention Facility in Road Tunnels', the thermal buoyancy has to be taken into account when calculating the capacity of jet fans for smoke control in tunnel fires. However, there is no detailed methodologies for considering thermal buoyancy, so further study is needed. In this study, the thermal buoyancy in the tunnel is calculated by 3-D numerical simulation to consider the thermal buoyancy in case of fire in tunnels, and the relationship between heat buoyancy and vehicle drag, And the method of calculating the capacity of the jet fan for smoke control in tunnels. According to the analysis results, heat buoyancy acts as a resistance force in the case of a down-slope tunnel, and the pressure rise of jet fan for smoke control is not simply determined by the value of heat buoyancy at the entrance of the tunnel and the value of the vehicle drag at the exit. And it is analyzed that it is necessary to carry out a comprehensive review according to the location of the fire vehicle in tunnels.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.2
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• pp.164-172
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• 2015

Seoul subway plays an important part for the public transportation service in Seoul metropolitan area. As the subway system is typically a closed environment, frequent air pollution problems occurred and passengers get malhealth impact. Especially particulate matters (PM) is well known as one of the major pollutants in subway environments. The purpose of this study was to compare the concentrations of $PM_{10}$ and $PM_{2.5}$ in the Seoul subway system and to provide fundamental data in order to management of subway system. $PM_{10}$ and $PM_{2.5}$ samples were collected in the M station platform and tunnel of Subway Line 4 in Seoul metropolitan and in an outdoor location close to it from Apr. 21, 2010~Oct. 27, 2013. The samples collected on teflon filters using $PM_{10}$ and $PM_{2.5}$ mini-volume portable samplers and PM sequential sampler. The PM contributions were $48.6{\mu}g/m^3$ (outdoor), $84.6{\mu}g/m^3$ (platform) and $204.8{\mu}g/m^3$ (tunnel) for $PM_{10}$, and $34.6{\mu}g/m^3$ (outdoor), $49.7{\mu}g/m^3$ (platform) and $83.1{\mu}g/m^3$ (tunnel) for $PM_{2.5}$. The $PM_{10}$ levels inside stations and outdoors are poorly correlated, indicating that $PM_{10}$ levels in the metro system are mainly influenced by internal sources. In this study, we compared PM concentrations before and after operation of ventilation and Electrostatic Precipitator (EP). Despite the increased PM concentration at outdoor, $PM_{10}$ concentration at platform and tunnel showed the 31.2% and 32.3% reduction efficiency after operation the reduction system. The overall results of this study suggest that the installation and operation of the ventilating system and EP should have served as one of the important components for maintaining the air quality in the subway system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.778-786
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• 2012

Sensors that are used on wireless sensor networks can be divided into two types: directional sensors, such as PIR, image, and electromagnetic sensors; and non-directional sensors, such as seismic, acoustic and magnetic sensors. In order to guarantee the line-of-sight of a directional sensor, the installation location of the sensor must be higher than ground level. Among non-directional sensors, seismic sensors should be installed on the ground in order to ensure the maximal performance. As a result, seismic sensors may have network connectivity problems due to communication failure. In this paper, we propose a 3D node deployment method to maximize the coverage and the network connectivity considering the sensor-specific properties. The proposed method is for non-directional sensors to be placed on the ground, while the directional sensor is installed above the ground, using trees or poles, to maximize the coverage. As a result, through the topology that the detection data from non-directional sensors are transmitted to the directional sensor, we can maximize the network connectivity. Simulation results show that our strategy improves sensor coverage and network connectivity.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.2
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• pp.53-59
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• 2008

As cities become more industrial and modern, they become overcrowded and the construction zones increase accordingly. In particular, the demand for panel-type planting methods has gradually increased due to early planting and easy installation. However, studies on panel-type planting have strictly concentrated on the vegetation sub system or irrigation system without any interest in landscape-centered system. Factors of preference will be made through landscape evaluation on the panel-type facade planting. A questionnaire survey was conducted in a location where panel-type facade planting was available. In terms of responses to the facade planting, 'natural (3.80)' was the highest, followed by 'friendly (3.70),' 'comfortable (3.65),' 'beautiful (3.65),' and 'peaceful (3.50).' On the contrary, negative responses such as 'too quiet,' 'simple,' 'heavy,' 'gloomy,' 'dark,' and 'dirty' were also received. It is thought that these responses refer to the poor management of the area. The results of this study will be useful as basic data for the development and distribution of panel-type facade planting.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.164-175
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• 2019

Installation of digital tachograph, black box, and ADAS have been enforced to commercial vehicles for preventing violent driving and accidents by the Traffic Safety Act in Korea. Nevertheless, the damage caused by road hazards has increased 1.5 times in 2016 compared to 2013. So, developing new technologies that can identify road hazard using the sensors installed in commercial vehicles are conducting by the Ministry of Land, Infrastructure and Transport. As a part of the technologies, this research analyze the error range of GPS installed in commercial vehicles that vary according to the driving speed. As a result, the average error was 9.72m at the driving speed of 100km/h, and the error was 2.1 times larger than the average error of 4.69m at the driving speed of 40km/h. The event point proper integration/separation range(m) was analyzed to be 20m with a recognition rate of 90% or more at the same point regardless of driving speed. The results of this research can be used as basic data for improving the accuracy of location-based data would be collected using commercial vehicles.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.525-529
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• 2015

Depending on the field of smart industry has become increasingly widespread, the digital signage industry as advertising and content industry is emerging. However, this industry is growing rapidly it is not the reason for that is lack of a legal definition or system. The current legal system merely existing laws that apply to the use of outdoor advertising such as advertising and outdoor advertising Electrical, according to a separate law on digital signage is still is not enough. Most of the current legal system between a size that it is put in the control object, its type, the installation location and details and locations of areas in accordance with the regulation member of the law which can reduce the effectiveness of such a business to control them collectively There is concern that the differences are caused by unification can be difficult. In reality, the institutions of the new law was necessary, organized under the existing regulation rather than promoting new laws to screen the effectiveness of the national business media industry through a kind of standardization and unification of the digital signage industry in the future creation of a jurisdiction other than safety administration Science It is important to foster.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.922-929
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• 2005

This paper proposes an adaptive pilot beacon equipment for mobile communication systems based on direct spread spectrum technology which generates the pilot channel for handoff between base stations by using the information acquired from the downstream wireless signal regarding the overhead channel information. Such an adaptive pilot beacon equipment will enable low power operation since among the wireless signals, only the pilot channel will be generated and transmitted. The pilot channel in the downstream link of the CDMA receiver is used to acquire time and frequency synchronization and this is used to calibrate the offset for the beacon, which implies that time synchronization using GPS is not required and any location where forward receive signal can be received can be used as the installation site. The downstream link pilot signal searching within the CDMA receiver is performed by FPGA and DSP. The FPGA is used to perform the initial synchronization for the pilot searcher and DSP is used to perform the offset correction between beacon clock and base station clock. The CDMA transmitter the adaptive pilot beacon equipment will use the timing offset information in the pilot channel acquired from the CDMA receiver and generate the downstream link pilot signal synchronized to the base station. The intermediate frequency signal is passed through the FIR filter and subsequently upconverted and amplified before being radiated through the antenna.