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        검색결과 464

        381.
        2011.10 KCI 등재 서비스 종료(열람 제한)
        디벤바키아, 벤자민고무나무, 그리고 아레카야자를 이용하여 화분의 지피물질에 따른 포름알데히드 제거 효율을 측정하였다. 화분 지피물질로는 가는 자갈, 모래, 수태, 셀라지넬라를 이용하였다. 셀라지넬라 지피가 포름알데히드 제거 효율이 가장 높았고, 모래 지피가 가장 낮았다. 가스 처리 2시간 후 셀라지넬라 지피의 포름알데히드 제거율은 모래에 비해 25% 높게 나타났다. 지피 방법과는 상관없이 식물 종류별로 포름알데히드 제거율을 비교하면 디벤바키아가 가장 우수하였고 그 다음이 벤자민고무나무, 아레카야자 순이었다. 지피 방법별 초기 가스 농도의 절반에 도달하는 T50%은 자갈, 모래, 수태 그리고 셀라지넬라가 각각 88, 118, 81, 53(분)이었다. 이러한 결과는 지피물질에 따라 오염된 공기가 근권부에 도달하는 양이 다르기 때문으로 보인다. 결과적으로 지피물질별 포름알데히드 제거 효율은 셀라지넬라가 가장 우수하였다.
        382.
        2011.10 KCI 등재 서비스 종료(열람 제한)
        라돈(222Rn)은 지각의 암석이나 토양 또는 건축자재 중에 들어 있는 우라늄(238U)과 토륨(232Th)이 몇 단계의 방사성붕괴 과정을 거친 후 생성되는 무색무취의 불활성기체로 광산이나 지하같이 밀폐된 공간에 잘 축적된다. 호흡기를 통하여 폐로 유 입되고 라돈의 딸핵종이 폐나 기관지에 침적되어 폐암을 일으키는 원인이 된다. 사람의 생명을 다루는 의료기관에서의 라돈피 폭은 평상시 방사선피폭량이 많은 방사선관계종사자와 면역력이 약한 환자에게 큰 위험이 될 수 있다는 판단에 이 실험을 실 시하였다. 실험에 쓰인 계측기는 실시간 라돈측정기인 Professional Continuous Radon monitor이며 계측장소는 두 개의 병원 지하1 층에서 지상2층까지 층별로 오전 10시부터 오후 3시까지 측정 하였다. Professional Continuous Radon monitor계측결과는 최 소 14.8 Bq/㎥에서 최대 70.3 Bq/㎥로 국내기준치인 148 Bq/㎥이하로 나타났으며 유효선량은 최소 0.296 mSv에서 최대 1.406 mSv로 일년간 자연방사선으로부터 피폭되는 방사선량인 2.4 mSv의 10~58.3% 수준으로 나타났다.
        383.
        2011.08 KCI 등재 서비스 종료(열람 제한)
        This paper presents a localization system using ceiling images in a large indoor environment. For a system with low cost and complexity, we propose a single camera based system that utilizes ceiling images acquired from a camera installed to point upwards. For reliable operation, we propose a method using hybrid features which include natural landmarks in a natural scene and artificial landmarks observable in an infrared ray domain. Compared with previous works utilizing only infrared based features, our method reduces the required number of artificial features as we exploit both natural and artificial features. In addition, compared with previous works using only natural scene, our method has an advantage in the convergence speed and robustness as an observation of an artificial feature provides a crucial clue for robot pose estimation. In an experiment with challenging situations in a real environment, our method was performed impressively in terms of the robustness and accuracy. To our knowledge, our method is the first ceiling vision based localization method using features from both visible and infrared rays domains. Our system can be easily utilized with a variety of service robot applications in a large indoor environment.
        384.
        2011.04 KCI 등재 서비스 종료(열람 제한)
        본 연구는 실내식물의 시각적 이미지가 주는 심리적 효과와 식물에 대한 관심도와의 관계, 식불에 대한 관심도와 중요도가 충성도에 미치는 영향을 분석하기 위해 실시히였다. 9종의 실내 식물에 대한 14쌍의 이미지 감성형용사 어휘는 평가적인, 활동적인 그리고 정서적인 요인의 세 가지 주요인이 추출되었다. 추출된 세 가지 이미지 감성요인 중 활동적인 요인보디는 평가적인 요인이, 평가적인 요인보다는 정서적인 요인이 실내 식물의 관심도에 미치는 영향이 상대적으로 더 높은 것으로 나타났다(p<.05). 또한 대상자들의 실내식물을 키우는 것에 대한 관심도는 충성도에 매우 긍정적인 영향을 주는 것으로 나타났으나(p<.05) , 연간 구입 개수,구입 비용,실내 식물을 키우는 형태와 같은 행동적 요소는 경우에 따라 유의한 차이가 없는 것으로 나타났다. 실내 식물에 대한 중요성의 인식에 있어서 실내식물에 대한 22항목의 중요도는 6가지 주요인이 추출되었다. 추출된 요인 종 삶의 질적 향상을 위한 "정서이완성”,“심미성”의 개념에 해당하는 항목들의 경우 다른 요인에 비해 충성도에 더 긍정적인 영향을 주는 것으로 나타났다(p<.05). 그러나 5가지 충성도의 항목 중 “실내 식물 구입에 더 많은 비용을 투자할 용의가 있다"는 항목은 다른 항목에 비해 충성도가 상대적으로 낮은 것으로 나타났다. 본 연구를 통해 각 식물의 시각적 이미지가 주는 심리적 효과, 실내식물에 대한 관심도,그리고 중요성 인식은 거주자의 정서적 건강 증진과 실내 식물의 소비를 높이는 데 긍정적인 영향을 줄 수 있는 실내식물에 대한 충성도를 향상시킬 수 있을 것으로 판단된다.
        385.
        2011.02 KCI 등재 서비스 종료(열람 제한)
        This paper proposes a technique of indoor localization for mobile robot by so called indoor GPS and EKF. Basically the concept of indoor GPS is similar outdoor GPS, and the indoor GPS gets distances between Anchors and Tag by a ranging method of CSS and then estimates the coordinate by distances and known Anchor positions. After we performed performance test of indoor GPS system in ideal and multipath environment, we configured that the indoor GPS has internal error factors and external error factors. This paper handled a multipath problem belonging to external error factors. At first various direct physical method are introduced to fix the multipath problems, and as expected we got errors corrected considerably. And then the method of selective anchors for indoor GPS is applied. With these two level improvement of indoor GPS performance, EKF(Extended Kalman Filter) is applied to mobile robot in indoor environment. The usefulness of the proposed methods are shown by a series of experiments in a environment giving contaminated data by multipath.
        386.
        2011.02 KCI 등재 서비스 종료(열람 제한)
        The human-following is one of the significant procedure in human-friendly navigation of mobile robots. There are many approaches of human-following technology. Many approaches have adopted various multiple sensors such as vision system and Laser Range Finder (LRF). In this paper, we propose detection and tracking approaches for human legs by the use of a single LRF. We extract four simple attributes of human legs. To define the boundary of extracted attributes mathematically, we used a Support Vector Data Description (SVDD) scheme. We establish an efficient leg-tracking scheme by exploiting a human walking model to achieve robust tracking under occlusions. The proposed approaches were successfully verified through various experiments.
        387.
        2011.01 KCI 등재 서비스 종료(열람 제한)
        Perceived air quality (PAQ) is defined as evaluation of indoor air satisfaction and comfortable sensory by occupants. However, there are differences between criteria of indoor pollutants and lowest sensory thresholds. In this study, we compared indoor PAQ by questionnaire with measured benzene, toluene and nitrogen dioxide (NO2) concentrations in home indoors. The NO2 concentration was the highest in Seoul, while benzene and toluene were the highest in Asan. Average PAQ score in winter was higher than that in summer. Significant correlations between PAQs of home indoor air pollution and measured pollutant concentrations were not shown and correlation coefficients (r) ranged between -0.453<r<0.258. Several groups have been divided to analyze what may affect PAQ scores such as gender, city, home indoor smoking, passive smoking, and self-reported respiratory symptoms. Gender, city, and self-reported respiratory symptoms by indoor air quality were associated with high PAQ scores by using of logistic regression analysis. We are confirmed that no association between concentrations of home indoor pollutant and PAQ scores. Therefore we further need to develop new indicator indoor air pollutants, measurement, and evaluation by PAQ.
        388.
        2010.11 KCI 등재 서비스 종료(열람 제한)
        A gradient method can provide a global optimal path in indoor environments. However, the optimal path can be often generated in narrow areas despite a sufficient wide area which lead to safe navigation. This paper presents a novel approach to path planning for safe navigation of a mobile robot. The proposed algorithm extracts empty regions using a ray-casting method and then generates temporary waypoints in wider regions in order to reach the goal fast and safely. The experimental results show that the proposed method can generate paths in the wide regions in most cases and the robot can reach the goal safely at high speeds.
        391.
        2010.08 KCI 등재 서비스 종료(열람 제한)
        For indoor mobile robots, the performance of autonomous navigation is affected by a variety of factors. In this paper, we focus on the characteristics of indoor absolute positioning systems. Two commercially available sensor systems are experimentally tested under various conditions. Mobile robot navigation experiments were carried out, and the results show that resultant performance of navigation is highly dependent upon the characteristics of positioning systems. The limitations and characteristics of positioning systems are analyzed from both quantitative and qualitative point of view. On the basis of the analysis, the relationship between the positioning system characteristics and the controller design are presented.
        392.
        2010.07 KCI 등재 서비스 종료(열람 제한)
        The study is about variations in Carbonyl compounds concentration within apartment buildings according to pre-residence and residence. We consecutively investigated indoor air pollutants in 120 households in 6 cities at pre-residence and residence. Carbonyl compounds were collected using the 2,4-DNPH cartridge and were analyzed using HPLC. The carbonyls concentration of indoor air in the new apartments before occupation measured formadlehyde(76.0㎍/㎥), acetone(85.9㎛/㎥), acetaldehyde(13.8㎍/㎥). The carbonyls concentration of indoor air in the new apartments after occupation measured formadlehyde(233.1㎍/㎥), acetone(128.9㎍/㎥), acetaldehyde(29.8㎍/㎥), respectively. As a result, the mean concentration of carbonyl compounds within the pre-occupancy stage was lower than those of residence.
        393.
        2010.06 서비스 종료(열람 제한)
        ○ 실내식물 92종에 대해 5그룹으로 분류하여 새집증후군의 대표적인 원인 물질인 포름알데히드의 시간당 제거 효율을 조사하여 값을 표시하고 순위에 따라 배열하였다. - 양치류의 포름알데히드 제거 효율이 가장 우수하였으며, 그 다음이 허브류이었다. 또한 목본성과 초본성 관엽식물, 자생식물 및 난의 포름알데히드 제거효율은 큰 차이를 보이지 않았다. ○ 실내식물 92종 중에 고비, 부처손, 넉줄고사리의 포름알데히드 제거효율이 가장 우수하였다. - 자생식물에서는 남천, 황칠나무, 백량금, 월계수, 마삭줄의 제거 효율이 우수였다. - 목본성 관엽식물 중에는 구아바, 관음죽, 메시코소철, 디지고데카, 인도고무나무 등이 우수하고, 초본성 관엽식물 중에는 접란, 디펜바키아, 틸란드시아, 안스리움, 싱고니움 등의 제거효율이 우수하였다. - 허브식물 중에서는 라벤더, 제라니움, 로즈마리 그리고 난류에서는 나도풍란, 덴파레, 호접란의 제거 효율이 우수하였다.
        394.
        2010.02 KCI 등재 서비스 종료(열람 제한)
        The most important factors relating to the indoor air environment are temperature, airflow, humidity, and contaminant concentration. A sensitivity analysis of indoor environment factors was carried out to grasp influences along with changes of atmospheric conditions. An integrated multizone model was used to predict these sensitivities. This model was applied to an apartment with six zones. Airflow rates are influenced very seriously by changes of wind direct or wind velocity, but are influenced very slightly by changes of outdoor air temperature and are not influenced at all by changes of outdoor air humidity or contaminant concentration. Indoor air temperatures are influenced very directly by changes of outdoor air temperature, but are influenced very slightly by wind direction or wind velocity and are not influenced at all by changes of outdoor air humidity or contaminant concentration. Indoor air humidities are influenced very directly by changes of outdoor air humidity, but are not influenced at all by changes of outdoor air contaminant concentration and have little or no influence by changes of wind direction, wind velocity, or outdoor air temperature. Indoor air contaminant concentrations are influenced very seriously by changes of wind direct or wind velocity, but are influenced somewhat by changes of outdoor air contaminant concentration and are influenced very slightly by changes of outdoor air temperature and are not influenced at all by changes of outdoor air humidity.
        395.
        2009.12 KCI 등재 서비스 종료(열람 제한)
        실내조경용 화분에서 사용되는 관수방법별 배지의 수분분포 및 심지종류별 수분흡수 특성을 구명하였다. 심지 종류는 극세사, 관수용 부직포, 면제품 그리고 관수방법은 물뿌리개, 점적핀, 그리고 심지 관수로 처리하였다. 관수용 심지 3종류의 수분흡수 높이는 제품 간에 큰 차이가 있었으나, 배지로 이동되는 수분 공급 높이는 15일 동안 약 20 cm로 처리 간에 차이가 없었다. 또한 심지의 수분 흡수속도는 초기 30분 동안(약 20 cm 높이) 빠른 속도로 흡수된 후 느려지는 특성을 보였다. 관수용 심지는 1차, 2차 흡수지대로 구분되며 1차 흡수지대는 심지가 침지된 물에 의해 직접 흡수되며 흡수속도가 빨랐다. 2차 흡수지대는 1차 흡수지대에 의해 공급된 배지의 물이 공급원이 되어 다시 심지에 흡수되는 곳으로, 흡수 속도가 느리고 흡수된 후 배양토로 이동이 어려운 것으로 보인다. 물뿌리개를 이용한 관수는 많은 물이 짧은 시간에 수평으로 공급되지만 점적관수의 경우 원형으로 공급되고(Snyder 1990) 심지관수의 경우에는 천천히 적은 물이 옆으로 공급되는 특성을 나타낸다. 결과적으로 관수용 심지는 재질에 관계없이 배양토 높이 약 15 cm까지가 수분 공급이 가장 원활히 이루어지며, 높이 약 20 cm에 수분 이용한계선이 존재한다. 또한 건물내에 식물의 증발산양이 적은 곳에서 사용되는 미세관수에는 심지 관수방법이 적합한 것으로 보인다.
        396.
        2009.11 KCI 등재 서비스 종료(열람 제한)
        This paper proposes a low-complexity indoor localization method of mobile robot under the dynamic environment by fusing the landmark image information from an ordinary camera and the distance information from sensor nodes in an indoor environment, which is based on sensor network. Basically, the sensor network provides an effective method for the mobile robot to adapt to environmental changes and guides it across a geographical network area. To enhance the performance of localization, we used an ordinary CCD camera and the artificial landmarks, which are devised for self-localization. Experimental results show that the real-time localization of mobile robot can be achieved with robustness and accurateness using the proposed localization method.
        397.
        2009.11 KCI 등재 서비스 종료(열람 제한)
        FastSLAM is a factored solution to SLAM problem using a Rao-Blackwellized particle filter. In this paper, we propose a practical FastSLAM implementation method using an infrared camera for indoor environments. The infrared camera is equipped on a Pioneer3 robot and looks upward direction to the ceiling which has infrared tags with the same height. The infrared tags are detected with the infrared camera as measurements, and the Nearest Neighbor method is used to solve the unknown data association problem. The global map is successfully built and the robot pose is predicted in real time by the FastSLAM2.0 algorithm. The experiment result shows the accuracy and robustness of the proposed method in practical indoor environment.
        399.
        2009.10 KCI 등재 서비스 종료(열람 제한)
        This study was designed to evaluate qualitatively and quantitatively the pollutant compositions, which were emitted from three types of mosquito repellents(MRs)(mat-, liquid-vaporized, and coil-type) by utilizing a 50-L environmental chamber. A qualitative analysis revealed that 42 compounds were detected on the gas chromatography/ mass spectrometer system, and that the detection frequency depended upon chemical types. Nine of the 42 compounds exhibited a detection frequency of 100%. Four aromatic compounds(benzene, ethyl benzene, toluene, and xylene) were detected in all test MRs. The concentration equilibriums in the environmental chamber were achieved within 180 min after sample introduction. The coil-type MR represented higher chamber concentrations as compared with the mat- or liquid-vaporized-type MR, with respect to the target compounds except for naphthalene. In particular, the chamber concentrations of ethyl benzene, associated with the use of coil-type MR, were between 0.9 and 65 mg m-3, whereas those of mat- and liquid-vaporized-type MRs were between 0.5 and 2.0 mg m-3and 0.3 and 1.4 mg m-3, respectively. However, naphthalene concentrations in the chamber, where a liquid-vaporized-type MR was placed, were measured as between 17.8 and 56.3 mg m-3, but not detected in the chamber, where a mat- or coil-type MR was placed. The empirical model fitted well with the time-series concentrations in the environmental chamber(in most cases, determination coefficient, R2 ≳ 0.9), thereby suggesting that the model was suitable for testing emissions. In regards to the target compounds except for benzene, although they were emitted from the MRs, health risk from individual exposure to them were estimated not to be significant when comparing exposure levels with no observed adverse exposure levels or lowest observed adverse exposure levels of corresponding compounds. However, it was concluded that the use of MRs could be an important indoor source as regards benzene.
        400.
        2009.06 KCI 등재 서비스 종료(열람 제한)
        The living performances of crews and passengers in cabins have been less received attention, while Korea is a top leading country in ship building industry. To develop a high value added ships like 5-star cruisers, researches on the comfort and productivity in cabins should be carried out with urgent. The purpose of this study is to measure and analyze of the ship's indoor thermal conditions in spring, summer and winter, and also to compare the seasonal differences, of which conditions are supplied from and controlled by marine HVAC The temperature, humidity and air supply volume of 5 different needs of cabins on a training ship were measured through a year, which was launched at Dec. 2005 and totally 246 crews can go on board for education. The following results were obtained: (1)In the spring, the temperature in cabins was measured as 20~25℃ and humidity was below 30%. (2)In the summer, the temperatures was controlled at 21~27℃ in almost cabins and humidity was between 40~60% which is known as comfort conditions. (3)In the winter, temperature and humidity was maintained between 19~26℃, and humidity was between 10~50%. (4)It is clear that the humidity conditions in cabins are not properly controlled at all through a year to satisfy the Comfort Standards provided by ASHRAE and/or ISO, In conclusion, humidification and dehumidification of cabins must be treated with importance for more comfort living and working environments for crews and passengers.