• 한국군사과학기술학회지
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• 제20권1호
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• pp.55-62
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• 2017

For evaluating a large caliber ammunition tests, indoor ballistic test range is required to reduce the noise and fragments occurring during the test. To ensure the reliability of the indoor ballistics test range design, we carried out the analysis of the indoor test range using the AUTODYNE hydrodynamic code before its construction. The 120 mm tank ammunition is adopted as a reference model and we analysed the characteristics of the pressure distribution at fire area, the structure design at impact area, the over-pressure applied to the tunnel, and the sabot stopper design. The results of the analysis were applied to the design of the indoor ballistic test range.

• KIEAE Journal
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• 제1권2호
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• pp.21-28
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• 2001

Naturally-ocurring short-lived decay products of radon gas in indoor air are the dominant source of ionizing radiation exposure to the general public. It is written in BEIR VI Report(l999l the radon progeny were identified as the second cause of lung cancer next to cigarette or 10 % to 14 %(15,400 to 21,800 persons p.a.) of all lung cancer deaths in USA. Indoor radon concentrations in houses typically result from radon gaining access to houses mainly from the underlying soil. In the States, they have "Indoor Radon Abatement Act" which was converted from "Toxic Substance Control Act" in 1988 to establish the national long-term goal that indoor air should be as free of radon as the ambient air outside of buildings. To review and study techniques for controlling radon, two test cells were constructed for a series of tests and are under measuring indoor and soil gas (underneath of floor slab)radon concentrations according to EPA's measurement protocol. In this paper, important theoretical studies are previewed and the following paper will explain the test results and confirm the theories reviewed to find out suitable coefficients. On the basis of test analysis, it will be described and evaluated various techniques that can be used to mitigate elevated indoor concentration of radon including the control of radon and its decay products.

• 한국통신학회논문지
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• 제30권4C호
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• pp.207-214
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• 2005

옥내 무선 통신에서 심한 각도 퍼짐으로 인해 생기는 옥내 페이딩 영향을 극복하기 위해 수신기에 다중 안테나를 사용한 단일입력 다중출력의 옥내 무선 시스템 구조를 생각한다. 옥내 무선 통신의 성능 향상 방법으로 평균 주사 벡터 개념을 제안하고, PC와 무선 통신시스템 알고리즘을 사용한 검증 시스템을 제작하고, 알고리즘 성능을 분석한다. 또한, 전체 옥내 무선 시스템에 대한 검증 시스템의 동작 순서와 구조도 알아보고, 성능 분석을 통해 구현된 각 알고리즘들의 수행시간을 알아본다.

• International journal of advanced smart convergence
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• 제8권3호
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• pp.54-60
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• 2019

In this paper, a localization system for indoor objects is proposed. The proposed system consists of Beacons, LED Cells, Main Cell Controller (MCC), and Display. A Beacon is attached at each indoor object, and each LED cell has Beacon Scanner and VLC Transmitter. The Visual Light Communications (VLC) and Power Line Communications (PLC) methods are used to communicate the signals for localization of indoor objects. And the proposed system is designed, and implemented as a prototype. To certify that our propose d system can exactly localize a given indoor object, we take test for the implemented system as a p rototype. Here the location of the given indoor object is known. Test is done in two ways. The first is to check the operation of the detail of the system, and the second is the position recognition of i ndoor object. The second is the test of the implemented system to correctly detect the location of the indoor object with Beacon, while the object with Beacon is moved from location C to A. The experimental result shows that the system is exactly detect the moving locations. The system has the advantages of using previously installed power lines, and it does not need to use LAN lines or optical cables. The proposed system is usefully applied to indoor object localization area.

• KIEAE Journal
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• 제3권1호
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• pp.13-20
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• 2003

It is highly recognized that there is need for protection against indoor air pollution, as we realize environmental pollution is growing, For example, in an indoor environment, a person spends more than 80 percent of their time inside the building. Thus, concern about indoor decoration materials is growing, since they cause pollution in the rooms of an apartment, as well as in offices. As the indoor decoration materials become more diverse and lusurious, so the effect of VOCs(Volatile Organic Compounds) and HCHO(Formaldehy) is growing. The indoor decoration materials cause the Sick Building Syndrome, such as headaches, dizziness, or lack of concentraion, and they in turn cause serious deterioration in people's health. In this study, I probed the status of the indoor air pollution and carried on an investigation and analysis about the prevention technique. In doing so, I performed experimental tests and an assessment of the indoor decoration materials of an apartment. I also examined elements of the emitted and the emission. Finally, I examined the character of emissions, by changing environmental conditions, such as the temperature, humidity, and ventilation. With respect to VOCs tests, I applied the method of solid state adsorption using the adsorptive tube, based on the measurement of the American EPA TO-17, ASTM 5116-97, and the measurement of the Japanese Wall Decoration Industrial Association. The tested sample was analyzed by High Performance Liquid Chromatography, after going through the process of dissolvent extraction. As subjects of the test, Paint were selected. The process of this test is as follows; first, I figured out the character of the emission, by measuring the emitted concentration of VOCs and HOHC from the indoor decoration materials of an apartment. Second, I made a small-scale chamber and the test was processed in the chamber in order to suggest an environment-friendly prediction modlel development.

• 한국환경보건학회지
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• 제49권6호
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• pp.324-333
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• 2023

Background: Human exposure to phthalates in indoor environments occurs via dermal absorption, oral ingestion of indoor dust, and inhalation of indoor air. However, systematic studies to investigate the exposure rate to phthalates among the three exposure routes in indoor environments are currently limited. Objectives: A theoretical exposure ratio between inhalation and oral exposure was calculated based on the total amount of di(2-ethyl-hexyl) phthalate (DEHP) emitted into indoor air and deposited into floor dust in a test house. Methods: Flooring and wallpaper containing DEHP were installed in a test house and the concentration of DEHP in both indoor air and floor dust were monitored for five months. Based on the measured DEHP concentrations, the theoretical total amount ratio of DEHP that could be exposed through inhalation and oral ingestion was calculated. Results: Considering the period of operation in the test house, the theoretical total amount of DEHP through inhalation and oral ingestion exposures in the entire test house space was calculated to be 0.014 mg and 5.5 mg, respectively. The exposure ratio of the two routes between inhalation and oral exposure corresponding to the total DEHP amount in flooring and wallpaper was 6.0×10^-7% and 2.3×10^-4%, indicating that theoretical oral exposure to DEHP is approximately 380 times higher than inhalation. Conclusions: Monitoring results from a test house has shown that oral exposure is the main exposure route for DEHP in indoor environments. The experimental design employed in this study and theoretical exposure ratio obtained can be applied to investigate actual exposure to DEHP and to determine the exposure characteristics of various types of semi-volatile organic compounds.

• 한국환경보건학회지
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• 제43권4호
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• pp.267-272
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• 2017

Objectives: The purposes of the study were to analyze the temporal variation of carbon dioxide ($CO_2$) and particulate matter (PM) in daycare centers and evaluate the appropriateness of the official test method of one-time measurement. Methods: Indoor air quality in 46 daycare centers in the Seoul Metropolitan Area was measured as specified in the official test method of Indoor Air Quality Management law. In addition, indoor air quality in the 46 daycare centers was measured over 37 days using a real-time monitor (AirGuard K). Results: The daily means of $CO_2$ and PM in the 46 daycare centers were $1042.74{\pm}134.45ppm$ and $67.60{\pm}18.25{\mu}g/m^3$, respectively. Indoor air quality in the daycare centers showed significant temporal fluctuation. Measurements for single days were significantly different from the 37-day average exposure. Relative error of short term exposure decreased with an increase in the number of sampling days. The noncompliance rate for $CO_2$ using the official testing method was 2.17%, and none exceeded the $PM_{10}$ standard of $100{\mu}g/m^3$. With monitoring over 37 days, the daily noncompliance rate for $CO_2$ was 50.4% and the daily noncompliance rate for PM was 13.8%. Conclusions: When the official test method evaluates the indoor air at daycare centers one day per year, the results may not represent actual indoor air quality over a longer period of time. Real-time monitoring devices could be an alternative for managing indoor air quality.

• 한국환경보건학회지
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• 제32권4호
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• pp.292-303
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• 2006

The Volatile Organic Compounds(VOCs) are emitted from various sources and have lots of different form. Recently human are spending the many times at indoor area and indoor air pollution is issued the important social problem. The emission sources of indoor air pollutants are very various, also indoor building materials are composed of very complex chemical compounds, these indoor building materials discharge very much VOCs and other hazardous compounds. In this study, we performed the small chamber test to investigate the VOCs emission concentration and characteristics involving five kinds of the indoor building materials(furniture material, wooden floor, wall paper, paint and tile) under different conditions of four temperature and relative humidity as account of the air flow rate(AFR), air exchange rate(AER), loading factor and air velocity respectively. As the result, It was showed that building materials are emitted the highest VOCs concentration at the beginning of experiment and furniture material is emitted the highest VOCs concentration. Most of the materials were affected by temperature, but paint and tile material were affected by humidity.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.356-366
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• 2021

Objective: This study aimed to compare gait ability through gait evaluations in indoor and outdoor environments according to the general characteristics and walking ability of stroke patients. Design: Crossed-sectional study. Methods: The subjects of this study were 57 hospitalized stroke patients.The study subjects were asked to select an indoor environment and an outdoor environment in random order, and the Timed Up and Go Test (TUG), 10-Meter Walk Test (10MWT), Figure-Eight Walk Test (F8WT) and the Functional Gait Assessment (FGA) were used to assess each environment. Results: The TUG, 10MWT, F8WT time and number of steps, and FGA showed a significant decrease in gait ability in the outdoor environment compared to the indoor environment (p<0.05). Although the TUG, 10MWT, and the time required for the F8WT were statistically higher in the outdoor compared to the indoor environment at points 2, 3, and 4, but not 5 of the functional ambulatory category (FAC), significant increases in the number of steps of the F8WT were found in the outdoor compared to the indoor environment for only points 2 and 3 of the FAC (p<0.05). In the FAC 3 and 4, there was a statistically significant decrease in the outdoor compared to the indoor environment only in the FGA (p<0.05). Conclusions: Therefore, it has been shown that the gait ability of stroke patients is reduced in the outdoor environment compared to the gait ability in the indoor environment.

• 항공우주기술
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• 제13권2호
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• pp.73-79
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• 2014

큐브위성 비행 소프트웨어 개발과정에서 큐브위성과 지상국간 데이터 송수신 시험이 필요한데 지상국 구축 비용과 공간성 등을 고려해 야외용 안테나를 사용하지 않는 실내용 지상국이 적합하다. 실내용 지상국 구축시 송신 출력이 높으면 큐브위성 통신시스템의 고장을 유발할 수 있음으로 지상국의 송신 출력이 큐브위성 통신시스템의 수신 허용범위 안에 있도록 설계하고, 이를 검증해야 한다. 본 논문에서는 UHF 및 VHF 주파수를 사용하는 큐브위성과의 데이터 송수신을 위한 실내용 지상국 구축에 대해 기술한다. 특히, 송신 출력을 저감하기 위한 방법으로 감쇄기를 사용하였는데, 송신단에 감쇄기를 연결하여 송신 출력과 감쇄기 수에 따른 감쇄 정도를 측정하고 이의 결과를 분석하여 기술하였다.